Sample records for future freshwater availability
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Osland, Michael J.; Enwright, Nicholas M.; Stagg, Camille L.
2014-01-01
Climate gradient-focused ecological research can provide a foundation for better understanding critical ecological transition points and nonlinear climate-ecological relationships, which is information that can be used to better understand, predict, and manage ecological responses to climate change. In this study, we examined the influence of freshwater availability upon the coverage of foundation plant species in coastal wetlands along a northwestern Gulf of Mexico rainfall gradient. Our research addresses the following three questions: (1) what are the region-scale relationships between measures of freshwater availability (e.g., rainfall, aridity, freshwater inflow, salinity) and the relative abundance of foundation plant species in tidal wetlands; (2) How vulnerable are foundation plant species in tidal wetlands to future changes in freshwater availability; and (3) What is the potential future relative abundance of tidal wetland foundation plant species under alternative climate change scenarios? We developed simple freshwater availability-based models to predict the relative abundance (i.e., coverage) of tidal wetland foundation plant species using climate data (1970-2000), estuarine freshwater inflow-focused data, and coastal wetland habitat data. Our results identify regional ecological thresholds and nonlinear relationships between measures of freshwater availability and the relative abundance of foundation plant species in tidal wetlands. In drier coastal zones, relatively small changes in rainfall could produce comparatively large landscape-scale changes in foundation plant species abundance which would affect some ecosystem good and services. Whereas a drier future would result in a decrease in the coverage of foundation plant species, a wetter future would result in an increase in foundation plant species coverage. In many ways, the freshwater-dependent coastal wetland ecological transitions we observed are analogous to those present in dryland terrestrial ecosystems.
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Fisheries indicators, freshwater
Kwak, Thomas J.
2010-01-01
Freshwater fisheries exist among diverse ecosystems and fauna, provide societal benefits, and are influenced by human activities. Fisheries scientists assess the status and sustainability of fisheries by multiple approaches, including abundance and condition indices, population parameters, community indices, modeling, and surveys of habitat and human dimensions. The future sustainability of freshwater fisheries is limited not by available methods but by society’s will.
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Reist, James D; Wrona, Frederick J; Prowse, Terry D; Dempson, J Brian; Power, Michael; Köck, Günter; Carmichael, Theresa J; Sawatzky, Chantelle D; Lehtonen, Hannu; Tallman, Ross F
2006-11-01
Fisheries for arctic freshwater and diadromous fish species contribute significantly to northern economies. Climate change, and to a lesser extent increased ultraviolet radiation, effects in freshwaters will have profound effects on fisheries from three perspectives: quantity of fish available, quality of fish available, and success of the fishers. Accordingly, substantive adaptation will very likely be required to conduct fisheries sustainably in the future as these effects take hold. A shift to flexible and rapidly responsive 'adaptive management' of commercial fisheries will be necessary; local land- and resource-use patterns for subsistence fisheries will change; and, the nature, management and place for many recreational fisheries will change. Overall, given the complexity and uncertainty associated with climate change and related effects on arctic freshwaters and their biota, a much more conservative approach to all aspects of fishery management will be required to ensure ecosystems and key fished species retain sufficient resiliency and capacity to meet future changes.
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Comment on ‘Water footprint of marine protein consumption—aquaculture’s link to agriculture’
NASA Astrophysics Data System (ADS)
Troell, Max; Metian, Marc; Beveridge, Malcolm; Verdegem, Marc; Deutsch, Lisa
2014-10-01
In their article ‘Freshwater savings from marine protein consumption’ (2014 Environ. Res. Lett. 9 014005), Gephart and her colleagues analyzed how consumption of marine animal protein rather than terrestrial animal protein leads to reduced freshwater allocation. They concluded that future water savings from increased marine fish consumption would be possible. We find the approach interesting and, if they only considered marine capture fisheries, their analysis would be quite straightforward and show savings of freshwater. However, both capture fisheries and aquaculture are considered in the analysis, and the fact that marine aquaculture is assumed to have a zero freshwater usage, makes the analysis incomplete. Feed resources used in marine aquaculture contain agriculture compounds, which results in a freshwater footprint. To correct this shortcoming we complement the approach taken by Gephart and her colleagues by estimating the freshwater footprint (WF) for crops used for feeding marine aquaculture. We show that this is critically important when estimating the true freshwater footprint for marine aquaculture, and that it will be increasingly so in the future. We also further expand on aquaculture’s dependency on fish resources, as this was only briefly touched upon in the paper. We do so because changes in availability of fish resources will play an important role for feed development and thereby for the future freshwater footprint of marine aquaculture.
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NASA Astrophysics Data System (ADS)
White, D. M.; Strang, E. T.; Alessa, L.; Hinzman, L.; Kliskey, A.
2005-12-01
The objective of this research is to understand how humans rely on freshwater at local and regional scales in selected parts of the Arctic, how these dependencies have changed in the recent past, and how they are likely to change in the future. The study seeks to incorporate likely effects of climate change on the hydrologic cycle and water availability to humans in the Arctic. The human demand for freshwater has risen dramatically over the past hundred years. Communities on the Seward Peninsula currently rely on both treated and traditional water sources for their drinking water. In many cases, availability of freshwater limits the use of both of these types of water sources. Future water demand predictions suggest that the demand for treated water will increase significantly as water systems are upgraded and the population of the area increases. Preliminary research indicates that water quality may by impacted by hydrologic changes, and further research is underway to determine the extent of these changes and how they will affect drinking water supplies on the Seward Peninsula. Understanding how climate change will impact the hydrology of this area will help minimize the impact these changes have on both engineered water systems and traditional water uses in the future. This presentation provides the most recent results of this research program. This study is being funded under the NSF Arctic System Science Program, Human Dimensions of the Arctic (OPP-0328686).
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Risk to Water Security on Small Islands
NASA Astrophysics Data System (ADS)
Holding, S. T.; Allen, D. M.
2013-12-01
The majority of fresh water available on small islands is shallow groundwater that forms a freshwater lens. Freshwater lenses are generally limited in extent and as such are vulnerable to many stressors that impact water security. These include stressors related to climate change, such as sea level rise, as well as those related to human impacts, such as contamination. Traditionally, water security assessments have focussed on indicators that provide a snapshot of the current condition. However, recent work suggests that in order to effectively manage the water system, it is also important to consider uncertain future impacts to the system by evaluating how different stressors might impact water security. In this study, a framework for assessing risk to water security was developed and tested on Andros Island in The Bahamas. The assessment comprises two main components that characterise the water system: numerical modelling studies and a hazard survey. A baseline numerical model of the freshwater lens throughout Andros Island was developed to simulate the morphology of the freshwater lens and estimate the freshwater resources currently available. The model was prepared using SEAWAT, a density-dependent flow and solute transport code. Various stressors were simulated in the model to evaluate the response of the freshwater lens to predicted future shifts in climate patterns, sea level rise, and changes in water use. A hazard survey was also conducted on the island to collect information related to the storage of contaminants, sanitation infrastructure, waste disposal practices and groundwater abstraction rates. The results of the survey form a geo-spatial database of the location and associated hazards to the freshwater lens. The resulting risk framework provides a ranking of overall risk to water security based on information from the numerical modelling and hazard survey. The risk framework is implemented in a Geographic Information System (GIS) and provides a map of the risk to water security throughout Andros Island. It evaluates risk to water security for current and future scenarios and will enable water resource managers to effectively adapt to future impacts on water security.
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Future Freshwater Stress on Small Islands: Population, Aridity and Global Warming Targets
NASA Astrophysics Data System (ADS)
Karnauskas, K. B.; Schleussner, C. F.; Donnelly, J. P.; Anchukaitis, K. J.
2017-12-01
Small island developing states (SIDS) face multiple threats from anthropogenic climate change, including potential changes in freshwater resource availability. Future freshwater stress, including geographic and seasonal variability, has important implications for climate change adaptation scenarios for vulnerable human populations living on islands across the world ocean. Due to a mismatch in spatial scale between SIDS landforms and the horizontal resolution of global climate models (GCMs), SIDS are mostly unaccounted for in GCMs that are used to make future projections of global climate change and its regional impacts. Specific approaches are required to address this gap between broad-scale model projections and regional, policy-relevant outcomes. Here we apply a recently developed methodology to project future changes in aridity in combination with population projections associated with different shared socioeconomic pathways (SSPs) to evaluate overall changes in freshwater stress in SIDS at warming levels of 1.5°C and 2°C above pre-industrial levels. By accounting for evaporative demand a posteriori, we reveal a robust yet spatially variable tendency towards increasing aridity for 16 million people living on islands by mid-century. Although about half of the islands are projected to experience increased rainfall—predominantly in the deep tropics—projected changes in evaporation are more uniform, shifting the global distribution of changes in island freshwater balance towards greater aridity. In many cases, the magnitude of projected drying is comparable to the amplitude of the estimated observed interannual variability, with important consequences for extreme events. While we find that future population growth will dominate changes in projected freshwater stress especially towards the end of the century, projected changes in aridity are found to compound freshwater stress for the vast majority of SIDS. Particularly across the Caribbean region, a substantial fraction ( 25%) of the large overall freshwater stress projected under 2°C at 2030 can be avoided by limiting global warming to 1.5°C. Our findings add to a growing body of literature on the difference in climate impacts between 1.5°C and 2°C and underscore the need for regionally specific analysis.
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Venteris, Erik R; Skaggs, Richard L; Coleman, Andre M; Wigmosta, Mark S
2013-05-07
A key advantage of using microalgae for biofuel production is the ability of some algal strains to thrive in waters unsuitable for conventional crop irrigation such as saline groundwater or seawater. Nonetheless, the availability of sustainable water supplies will provide significant challenges for scale-up and development of algal biofuels. We conduct a partial techno-economic assessment based on the availability of freshwater, saline groundwater, and seawater for use in open pond algae cultivation systems. We explore water issues through GIS-based models of algae biofuel production, freshwater supply (constrained to less than 5% of mean annual flow per watershed) and costs, and cost-distance models for supplying seawater and saline groundwater. We estimate that, combined, these resources can support 9.46 × 10(7) m(3) yr(-1) (25 billion gallons yr(-1)) of renewable biodiesel production in the coterminous United States. Achievement of larger targets requires the utilization of less water efficient sites and relatively expensive saline waters. Despite the addition of freshwater supply constraints and saline water resources, the geographic conclusions are similar to our previous results. Freshwater availability and saline water delivery costs are most favorable for the coast of the Gulf of Mexico and Florida peninsula, where evaporation relative to precipitation is moderate. As a whole, the barren and scrub lands of the southwestern U.S. have limited freshwater supplies, and large net evaporation rates greatly increase the cost of saline alternatives due to the added makeup water required to maintain pond salinity. However, this and similar analyses are particularly sensitive to knowledge gaps in algae growth/lipid production performance and the proportion of freshwater resources available, key topics for future investigation.
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NASA Astrophysics Data System (ADS)
Davies, F. J.; Goosse, H.; Renssen, H.
2012-04-01
The influence of freshwater on the long term climatic variability of the Arctic region is currently of significant interest. Alterations to the natural variability of the oceanic, terrestrial and atmospheric sources of freshwater to the Arctic ocean, caused by anthropogenic induced warming, are likely to have far reaching effects on oceanic processes and climate. A number of these changes are already observable, such as an intensification of the hydrological cycle, a 7% increase in Eurasian river runoff (1936-1999), a 9% reduction of sea-ice extent per decade (1979-2006), a 120km northward migration of permafrost in Northern Canada (1968-1994), and air temperatures 6°C warmer, in parts, from 2007 to 2010, when compared to the 1958-1996 average. All of these changes add another layer of complexity to understanding the role of the freshwater budget, and this makes it difficult to say with any certainty how these future changes will impact freshwater fluxes of the Arctic gateways, such as the Bering Strait, Fram Strait, Canadian Arctic Archipelago and the Barents Sea inflow. Despite these difficulties, there have been studies that have integrated the available data, from both in situ measurements and modelling studies, and used this as a basis to form a picture of the current freshwater budget, and then project upon these hypotheses for the future (Holland et al., 2007). However, one particular aspect of these future projections that is lacking is the accountability of how much future variance is attributable to both natural variability and anthropogenic influences. Here we present results of a mid to late (6-0ka) Holocene transient simulation, using the earth model of intermediate complexity, LOVECLIM (Goosse et al., 2010). The model is forced with orbital and greenhouse gas forcings appropriate for the time period. The results will highlight the natural variability of the oceanic, terrestrial and atmospheric components of the freshwater budget, over decadal and centennial timescales. When computing the freshwater budget for the period, where in situ measurements are available, LOVECLIM has been shown to perform reasonably well. The intention here is not to present a fully quantitative assessment of the freshwater budget of the Arctic Ocean as such, but to highlight the natural variability of the freshwater budget and its individual components. We hope that this inspires other modelling groups to take a similar approach and work towards understanding the natural variability of the freshwater budget over timescales longer than current measurements allow, and modelling studies have previously attempted. Goosse, H., Brovkin, V., Fichefet, T., Haarsma, R., Huybrechts, P., Jongma, J., Mouchet, A., Selten, F., Barriat, P-Y., Campin, J-M., Deleersnijder, E., Driesschaert, E., Goelzer, H., Janssens, I., Loutre, M-F., Morales Maqueda, M.A., Opsteegh, T., Mathieu, P-P., Munhoven, G., Pettersson, E.J., Renssen, H., Roche, D.M., Schaeffer, M., Tartinville, B., Timmermann, A., Weber, S.L. (2010) Description of the Earth System Model of Intermediate Complexity LOVECLIM Version 1.2, Geoscientific Model Development, 3:603-633 doi: 10.5194/gmd-3-603-2010. Holland, M.M., Finnis, J., Barrett, A.P., Serreze, M.C. (2007) Projected Changes in Arctic Ocean Freshwater Budgets, Journal of Geophysical Research, 112, G04S55, doi:10.1029/2006JG000354, 2007
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Estimated water use in Mississippi, 1980
Callahan, J.A.
1980-01-01
Large quantities of good quality ground and surface water are readily available in nearly all parts of Mississippi, and there is also an abundant supply of saline water in the estuaries along the Mississippi Gulf Coast. The total estimated water use in the State in 1980 from groundwater and surface water was 3532 million gallons/day (mgd), including 662 mgd of saline water. Freshwater used from all sources in Mississippi during the period 1975 through 1980 increased from 2510 mgd to > 2870 mgd, a 14% increase. Although modest increases of freshwater use may be expected in public, self-supplied industrial, and thermoelectric supplies, large future increases in the use of freshwater may be expected primarily as a result of growth in irrigation and aquaculture. Management and protection of the quantity and quality of the available freshwater supply are often problems associated with increased use. Water use data, both temporal and spatial, are needed by the State of Mississippi to provide for intelligent, long-term management of the resources; one table gives data on the principal categories of water use, sources, and use by county. (Lantz-PTT)
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Pope, Kevin L.; Hamel, Martin J.; Pegg, Mark A.; Spurgeon, Jonathan J.
2016-01-01
Age information derived from calcified structures is commonly used to estimate recruitment, growth, and mortality for fish populations. Validation of daily or annual marks on age structures is often assumed, presumably due to a lack of general knowledge concerning the status of age validation studies. Therefore, the current status of freshwater fish age validation studies was summarized to show where additional effort is needed, and increase the accessibility of validation studies to researchers. In total, 1351 original peer-reviewed articles were reviewed from freshwater systems that studied age in fish. Periodicity and age validation studies were found for 88 freshwater species comprising 21 fish families. The number of age validation studies has increased over the last 30 years following previous calls for more research; however, few species have validated structures spanning all life stages. In addition, few fishes of conservation concern have validated ageing structures. A prioritization framework, using a combination of eight characteristics, is offered to direct future age validation studies and close the validation information gap. Additional study, using the offered prioritization framework, and increased availability of published studies that incorporate uncertainty when presenting research results dealing with age information are needed.
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Martinuzzi, Sebastián; Januchowski-Hartley, Stephanie R; Pracheil, Brenda M; McIntyre, Peter B; Plantinga, Andrew J; Lewis, David J; Radeloff, Volker C
2014-01-01
Freshwater ecosystems provide vital resources for humans and support high levels of biodiversity, yet are severely threatened throughout the world. The expansion of human land uses, such as urban and crop cover, typically degrades water quality and reduces freshwater biodiversity, thereby jeopardizing both biodiversity and ecosystem services. Identifying and mitigating future threats to freshwater ecosystems requires forecasting where land use changes are most likely. Our goal was to evaluate the potential consequences of future land use on freshwater ecosystems in the coterminous United States by comparing alternative scenarios of land use change (2001-2051) with current patterns of freshwater biodiversity and water quality risk. Using an econometric model, each of our land use scenarios projected greater changes in watersheds of the eastern half of the country, where freshwater ecosystems already experience higher stress from human activities. Future urban expansion emerged as a major threat in regions with high freshwater biodiversity (e.g., the Southeast) or severe water quality problems (e.g., the Midwest). Our scenarios reflecting environmentally oriented policies had some positive effects. Subsidizing afforestation for carbon sequestration reduced crop cover and increased natural vegetation in areas that are currently stressed by low water quality, while discouraging urban sprawl diminished urban expansion in areas of high biodiversity. On the other hand, we found that increases in crop commodity prices could lead to increased agricultural threats in areas of high freshwater biodiversity. Our analyses illustrate the potential for policy changes and market factors to influence future land use trends in certain regions of the country, with important consequences for freshwater ecosystems. Successful conservation of aquatic biodiversity and ecosystem services in the United States into the future will require attending to the potential threats and opportunities arising from policies and market changes affecting land use. © 2013 John Wiley & Sons Ltd.
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Current and future effects of global change on a hotspot's freshwater diversity.
Gallardo, Belinda; Bogan, Arthur E; Harun, Sahana; Jainih, Leonardo; Lopes-Lima, Manuel; Pizarro, Manuel; Rahim, Khairul Adha; Sousa, Ronaldo; Virdis, Salvatore G P; Zieritz, Alexandra
2018-04-19
Deforestation, climate change and invasive species constitute three global threats to biodiversity that act synergistically. However, drivers and rates of loss of freshwater biodiversity now and in the future are poorly understood. Here we focus on the potential impacts of global change on freshwater mussels (Order Unionida) in Sundaland (SE Asia), a vulnerable group facing global declines and recognized indicators of overall freshwater biodiversity. We used an ensemble of distribution models to identify habitats potentially suitable for freshwater mussels and their change under a range of climate, deforestation and invasion scenarios. Our data and models revealed that, at present, Sundaland features 47 and 32 Mha of habitat that can be considered environmentally suitable for native and invasive freshwater mussels, respectively. We anticipate that by 2050, the area suitable for palm oil cultivation may expand between 8 and 44 Mha, representing an annual increase of 2-11%. This is expected to result in a 20% decrease in suitable habitat for native mussels, a drop that reaches 30% by 2050 when considering concomitant climate change. In contrast, the habitat potentially suitable for invasive mussels may increase by 44-56% under 2050 future scenarios. Consequently, native mussels may compete for habitat, food resources and fish hosts with invasive mussels across approximately 60% of their suitable range. Our projections can be used to guide future expeditions to monitor the conservation status of freshwater biodiversity, and potentially reveal populations of endemic species on the brink of extinction. Future conservation measures-most importantly the designation of nature reserves-should take into account trends in freshwater biodiversity generally, and particularly species such as freshwater mussels, vital to safeguard fundamental ecosystem services. Copyright © 2018 Elsevier B.V. All rights reserved.
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Lamsal, Pramod; Kumar, Lalit; Atreya, Kishor; Pant, Krishna Prasad
2017-12-01
Climate change (CC) threatens ecosystems in both developed and developing countries. As the impacts of CC are pervasive, global, and mostly irreversible, it is gaining worldwide attention. Here we review vulnerability and impacts of CC on forest and freshwater wetland ecosystems. We particularly look at investigations undertaken at different geographic regions in order to identify existing knowledge gaps and possible implications from such vulnerability in the context of Nepal along with available adaptation programs and national-level policy supports. Different categories of impacts which are attributed to disrupting structure, function, and habitat of both forest and wetland ecosystems are identified and discussed. We show that though still unaccounted, many facets of forest and freshwater wetland ecosystems of Nepal are vulnerable and likely to be impacted by CC in the near future. Provisioning ecosystem services and landscape-level ecosystem conservation are anticipated to be highly threatened with future CC. Finally, the need for prioritizing CC research in Nepal is highlighted to close the existing knowledge gap along with the implementation of adaptation measures based on existing location specific traditional socio-ecological system.
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A review of water use in the U.S. electric power sector: insights from systems-level perspectives
Thermoelectric power production comprised 41% of total freshwater withdrawals in the U.S., surpassing even agriculture. This review highlights scenarios of the electric sector’s future demands for water, including scenarios that limit both CO2 and water availability. A number o...
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NASA Astrophysics Data System (ADS)
Rotzoll, K.; Izuka, S. K.; Nishikawa, T.; Fienen, M. N.; El-Kadi, A. I.
2016-12-01
Some of the volcanic-rock aquifers of the islands of Hawaii are substantially developed, leading to concerns related to the effects of groundwater withdrawals on saltwater intrusion and stream base-flow reduction. A numerical modeling analysis using recent available information (e.g., recharge, withdrawals, hydrogeologic framework, and conceptual models of groundwater flow) advances current understanding of groundwater flow and provides insight into the effects of human activity and climate change on Hawaii's water resources. Three island-wide groundwater-flow models (Kauai, Oahu, and Maui) were constructed using MODFLOW 2005 coupled with the Seawater-Intrusion Package (SWI2), which simulates the transition between saltwater and freshwater in the aquifer as a sharp interface. This approach allowed coarse vertical discretization (maximum of two layers) without ignoring the freshwater-saltwater system at the regional scale. Model construction (FloPy3), parameter estimation (PEST), and analysis of results were streamlined using Python scripts. Model simulations included pre-development (1870) and recent (average of 2001-10) scenarios for each island. Additionally, scenarios for future withdrawals and climate change were simulated for Oahu. We present our streamlined approach and results showing estimated effects of human activity on the groundwater resource by quantifying decline in water levels, rise of the freshwater-saltwater interface, and reduction in stream base flow. Water-resource managers can use this information to evaluate consequences of groundwater development that can constrain future groundwater availability.
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NASA Astrophysics Data System (ADS)
de Souza, Gabriel Fernandes; Tan, Lippong; Singh, Baljit; Ding, Lai Chet; Date, Abhijit
2017-04-01
The paper presents a sustainable hybrid system, which is capable of generating electricity and producing freshwater from seawater using low grade heat source. This proposed system uses low grade heat that can be supplied from solar radiation, industrial waste heat or any other waste heat sources where the temperature is less than 150°C. The concept behind this system uses the Seebeck effect for thermoelectricity generation via incorporating the low boiling point of seawater under sub-atmospheric ambient pressure. A lab-test prototype of the proposed system was built and experimentally tested in RMIT University. The prototype utilised four commercial available thermoelectric generators (Bi2Te3) and a vacuum vessel to achieve the simultaneous production of electricity and freshwater. The temperature profiles, thermoelectric powers and freshwater productions were determined at several levels of salinity to study the influence of different salt concentrations. The theoretical description of system design and experimental results were analysed and discussed in detailed. The experiment results showed that 0.75W of thermoelectricity and 404g of freshwater were produced using inputs of 150W of simulated waste heat and 500g of 3% saline water. The proposed hybrid concept has demonstrated the potential to become the future sustainable system for electricity and freshwater productions.
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The future of the ogallala aquifer: We can measure it, but can we manage it?
USDA-ARS?s Scientific Manuscript database
Ensuring the availability of fresh water resources in sufficient quantity and quality to support human populations and surrounding ecosystems represents one of the grand challenges of our time. The Ogallala Aquifer, one of the largest freshwater aquifers in the world, is a prime example of the chall...
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Urban growth, climate change, and freshwater availability
McDonald, Robert I.; Green, Pamela; Balk, Deborah; Fekete, Balazs M.; Revenga, Carmen; Todd, Megan; Montgomery, Mark
2011-01-01
Nearly 3 billion additional urban dwellers are forecasted by 2050, an unprecedented wave of urban growth. While cities struggle to provide water to these new residents, they will also face equally unprecedented hydrologic changes due to global climate change. Here we use a detailed hydrologic model, demographic projections, and climate change scenarios to estimate per-capita water availability for major cities in the developing world, where urban growth is the fastest. We estimate the amount of water physically available near cities and do not account for problems with adequate water delivery or quality. Modeled results show that currently 150 million people live in cities with perennial water shortage, defined as having less than 100 L per person per day of sustainable surface and groundwater flow within their urban extent. By 2050, demographic growth will increase this figure to almost 1 billion people. Climate change will cause water shortage for an additional 100 million urbanites. Freshwater ecosystems in river basins with large populations of urbanites with insufficient water will likely experience flows insufficient to maintain ecological process. Freshwater fish populations will likely be impacted, an issue of special importance in regions such as India's Western Ghats, where there is both rapid urbanization and high levels of fish endemism. Cities in certain regions will struggle to find enough water for the needs of their residents and will need significant investment if they are to secure adequate water supplies and safeguard functioning freshwater ecosystems for future generations. PMID:21444797
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Why are freshwater fish so threatened?
Closs, Gerard P.; Angermeier, Paul; Darwall, William R.T.; Balcombe, Stephen R.
2015-01-01
Understanding why so many freshwater fish species are threatened requires some understanding of their biology, diversity, distribution, biogeography and ecology, but also some appreciation of the social, economic and political forces that are causing humans to destroy the natural ecosystems upon which we all ultimately depend. To begin to understand the diversity of freshwater fishes, we first need to consider the processes that generated and continue to sustain the diversity of species we see today. Based on an understanding of how freshwater fish diversity is generated and sustained, we consider how vulnerable or resilient various freshwater fishes are to the range of anthropogenic impacts that impinge on freshwater ecosystems. Finally, we discuss how social, political and economic drivers influence human impacts on natural systems, and the changes needed to current models of development that can lead to a sustainable future for humans and the diverse range of freshwater fish species with which we share our planet. The aim of this chapter is to provide an overview of the key issues and threats driving the declines in freshwater fish diversity identified in Chapter 1; subsequent chapters provide more detail on the key issues and address our options for developing a sustainable future for freshwater fishes.
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NASA Astrophysics Data System (ADS)
Knouft, J.; Ficklin, D. L.; Bart, H. L.; Rios, N. E.
2017-12-01
Streamflow and water temperature are primary factors influencing the traits, distribution, and diversity of freshwater species. Ongoing changes in climate are causing directional alteration of these environmental conditions, which can impact local ecological processes. Accurate estimation of these variables is critical for predicting the responses of species to ongoing changes in freshwater habitat, yet ecologically relevant high-resolution data describing variation in streamflow and water temperature across North America are not available. Considering the vast amount of web-accessible freshwater biodiversity data, development and application of appropriate hydrologic data are critical to the advancement of our understanding of freshwater systems. To address this issue, we are developing the "HydroClim" database, which will provide web-accessible (www.hydroclim.org) historical and projected monthly streamflow and water temperature data for stream sections in all major watersheds across the United States and Canada from 1950-2099. These data will also be integrated with FishNet 2 (www.fishnet2.net), an online biodiversity database that provides open access to over 2 million localities of freshwater fish species in the United States and Canada, thus allowing for the characterization of the habitat requirements of freshwater species across this region. HydroClim should provide a vast array of opportunities for a greater understanding of water resources as well as information for the conservation of freshwater biodiversity in the United States and Canada in the coming century.
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Vegetative community control of freshwater availability: Phoenix Islands case study
NASA Astrophysics Data System (ADS)
Engels, M.; Heinse, R.
2014-12-01
On small low islands with limited freshwater resources, terrestrial plant communities play a large role in moderating freshwater availability. Freshwater demands of vegetative communities are variable depending on the composition of the community. Hence, changes to community structure from production crop introductions, non-native species invasions, and climate change, may have significant implications for freshwater availability. Understanding how vegetative community changes impact freshwater availability will allow for better management and forecasting of limited freshwater supplies. To better understand these dynamics, we investigated three small tropical atolls in the Phoenix Island Protected Area, Kiribati. Despite their close proximity, these islands receive varying amounts of rainfall, are host to different plant communities and two of the islands have abandoned coconut plantations. Using electromagnetic induction, ground penetrating radar, soil samples, climate and satellite data, we present preliminary estimates of vegetative water demand for different tropical plant communities.
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Jeremias, Guilherme; Barbosa, João; Marques, Sérgio M; Asselman, Jana; Gonçalves, Fernando J M; Pereira, Joana L
2018-07-01
Freshwater ecosystems are amongst the most threatened ecosystems on Earth. Currently, climate change is one of the most important drivers of freshwater transformation and its effects include changes in the composition, biodiversity and functioning of freshwater ecosystems. Understanding the capacity of freshwater species to tolerate the environmental fluctuations induced by climate change is critical to the development of effective conservation strategies. In the last few years, epigenetic mechanisms were increasingly put forward in this context because of their pivotal role in gene-environment interactions. In addition, the evolutionary role of epigenetically inherited phenotypes is a relatively recent but promising field. Here, we examine and synthesize the impacts of climate change on freshwater ecosystems, exploring the potential role of epigenetic mechanisms in both short- and long-term adaptation of species. Following this wrapping-up of current evidence, we particularly focused on bringing together the most promising future research avenues towards a better understanding of the effects of climate change on freshwater biodiversity, specifically highlighting potential molecular targets and the most suitable freshwater species for future epigenetic studies in this context. © 2018 John Wiley & Sons Ltd.
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Conservation status of freshwater mussels in Europe: state of the art and future challenges.
Lopes-Lima, Manuel; Sousa, Ronaldo; Geist, Juergen; Aldridge, David C; Araujo, Rafael; Bergengren, Jakob; Bespalaya, Yulia; Bódis, Erika; Burlakova, Lyubov; Van Damme, Dirk; Douda, Karel; Froufe, Elsa; Georgiev, Dilian; Gumpinger, Clemens; Karatayev, Alexander; Kebapçi, Ümit; Killeen, Ian; Lajtner, Jasna; Larsen, Bjørn M; Lauceri, Rosaria; Legakis, Anastasios; Lois, Sabela; Lundberg, Stefan; Moorkens, Evelyn; Motte, Gregory; Nagel, Karl-Otto; Ondina, Paz; Outeiro, Adolfo; Paunovic, Momir; Prié, Vincent; von Proschwitz, Ted; Riccardi, Nicoletta; Rudzīte, Mudīte; Rudzītis, Māris; Scheder, Christian; Seddon, Mary; Şereflişan, Hülya; Simić, Vladica; Sokolova, Svetlana; Stoeckl, Katharina; Taskinen, Jouni; Teixeira, Amílcar; Thielen, Frankie; Trichkova, Teodora; Varandas, Simone; Vicentini, Heinrich; Zajac, Katarzyna; Zajac, Tadeusz; Zogaris, Stamatis
2017-02-01
Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life-history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is unevenly distributed with considerable differences in data quality and quantity among countries and species. To make conservation more effective in the future, we suggest greater international cooperation using standardized protocols and methods to monitor and manage European freshwater mussel diversity. Such an approach will not only help conserve this vulnerable group but also, through the protection of these important organisms, will offer wider benefits to freshwater ecosystems. © 2016 Cambridge Philosophical Society.
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Spatially explicit scenario analysis for hydrologic services in an urbanizing agricultural watershed
NASA Astrophysics Data System (ADS)
Qiu, J.; Booth, E.; Carpenter, S. R.; Turner, M.
2013-12-01
The sustainability of hydrologic services (benefits to people generated by terrestrial ecosystem effects on freshwater) is challenged by changes in climate and land use. Despite the importance of hydrologic services, few studies have investigated how the provision of ecosystem services related to freshwater quantity and quality may vary in magnitude and spatial pattern for alternative future trajectories. Such analyses may provide useful information for sustaining freshwater resources in the face of a complex and uncertain future. We analyzed the supply of multiple hydrologic services from 2010 to 2070 across a large urbanizing agricultural watershed in the Upper Midwest of the United States, and asked the following: (i) What are the potential trajectories for the supply of hydrologic services under contrasting but plausible future scenarios? (ii) Where on the landscape is the delivery of hydrologic services most vulnerable to future changes? The Nested Watershed scenario represents extreme climate change (warmer temperatures and more frequent extreme events) and a concerted response from institutions, whereas in the Investment in Innovation scenario, climate change is less severe and technological innovations play a major role. Despite more extreme climate in the Nested Watershed scenario, all hydrologic services (i.e., freshwater supply, surface water quality, flood regulation) were maintained or enhanced (~30%) compared to the 2010 baseline, by strict government interventions that prioritized freshwater resources. Despite less extreme climate in the Investment in Innovation scenario and advances in green technology, only surface water quality and flood regulation were maintained or increased (~80%); freshwater supply declined by 25%, indicating a potential future tradeoff between water quality and quantity. Spatially, the locations of greatest vulnerability (i.e., decline) differed by service and among scenarios. In the Nested Watershed scenario, although freshwater supply and surface water quality were sustained or enhanced overall, these hydrologic services declined in ~60% and 20% of the landscape, respectively. The greatest improvement for most hydrologic services corresponded to areas of restored wetland, forest and perennial crops, which were less vulnerable to future degradation. In the Investment in Innovation scenario, freshwater supply declined in almost the entire watershed; improvement of surface water quality and flood regulation occurred mainly in urban areas, where highly engineered systems made them less vulnerable. Overall, our results indicated that hydrologic services will respond differently to future climate and land-use change, and sustaining one may involve tradeoffs of another. Technological progress can conserve particular services but might not be the panacea for the future. How society reacts in the face of changes can have an important role in determining the pathways to the future and the provision and spatial patterns of ecosystem services.
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Rivera-Monroy, Victor H.; Twilley, Robert R.; Davis, Stephen E.; Childers, Daniel L.; Simard, Marc; Chambers, Randolph; Jaffe, Rudolf; Boyer, Joseph N.; Rudnick, David T.; Zhang, Keqi; Castañeda-Moya, Edward; Ewe, Sharon M.L.; Price, Rene M.; Coronado-Molina, Carlos; Ross, Michael; Smith, Thomas J.; Michot, Beatrice; Meselhe, Ehab; Nuttle, William; Troxler, Tiffany G.; Noe, Gregory B.
2011-01-01
The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional processes, mediated by water flow, control population and ecosystem dynamics across the EMER landscape. Tree canopies with maximum height -1) in the calcareous marl substrate and long hydroperiod. Phosphorus limits the EMER and its freshwater watersheds due to the lack of terrigenous sediment input and the phosphorus-limited nature of the freshwater Everglades. Reduced freshwater delivery over the past 50 years, combined with Everglades compartmentalization and a 10 cm rise in coastal sea level, has led to the landward transgression (~1.5 km in 54 years) of the mangrove ecotone. Seasonal variation in freshwater input strongly controls the temporal variation of nitrogen and P exports (99%) from the Everglades to Florida Bay. Rapid changes in nutrient availability and vegetation distribution during the last 50 years show that future ecosystem restoration actions and land use decisions can exert a major influence, similar to sea level rise over the short term, on nutrient cycling and wetland productivity in the EMER.
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Xanthos – A Global Hydrologic Model
DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Xinya; Vernon, Chris R.; Hejazi, Mohamad I.
Xanthos is an open-source hydrologic model, written in Python, designed to quantify and analyse global water availability. Xanthos simulates historical and future global water availability on a monthly time step at a spatial resolution of 0.5 geographic degrees. Xanthos was designed to be extensible and used by scientists that study global water supply and work with the Global Change Assessment Model (GCAM). Xanthos uses a user-defined configuration file to specify model inputs, outputs and parameters. Xanthos has been tested using actual global data sets and the model is able to provide historical observations and future estimates of renewable freshwater resourcesmore » in the form of total runoff.« less
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Xanthos – A Global Hydrologic Model
Li, Xinya; Vernon, Chris R.; Hejazi, Mohamad I.; ...
2017-09-11
Xanthos is an open-source hydrologic model, written in Python, designed to quantify and analyse global water availability. Xanthos simulates historical and future global water availability on a monthly time step at a spatial resolution of 0.5 geographic degrees. Xanthos was designed to be extensible and used by scientists that study global water supply and work with the Global Change Assessment Model (GCAM). Xanthos uses a user-defined configuration file to specify model inputs, outputs and parameters. Xanthos has been tested using actual global data sets and the model is able to provide historical observations and future estimates of renewable freshwater resourcesmore » in the form of total runoff.« less
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Different ecophysiological responses of freshwater fish to warming and acidification.
Jesus, Tiago F; Rosa, Inês C; Repolho, Tiago; Lopes, Ana R; Pimentel, Marta S; Almeida-Val, Vera M F; Coelho, Maria M; Rosa, Rui
2018-02-01
Future climate change scenarios predict threatening outcomes to biodiversity. Available empirical data concerning biological response of freshwater fish to climate change remains scarce. In this study, we investigated the physiological and biochemical responses of two Iberian freshwater fish species (Squalius carolitertii and the endangered S. torgalensis), inhabiting different climatic conditions, to projected future scenarios of warming (+3°C) and acidification (ΔpH=-0.4). Herein, metabolic enzyme activities of glycolytic (citrate synthase - CS, lactate dehydrogenase - LDH) and antioxidant (glutathione S-transferase, catalase and superoxide dismutase) pathways, as well as the heat shock response (HSR) and lipid peroxidation were determined. Our results show that, under current water pH, warming causes differential interspecific changes on LDH activity, increasing and decreasing its activity in S. carolitertii and in S. torgalensis, respectively. Furthermore, the synergistic effect of warming and acidification caused an increase in LDH activity of S. torgalensis, comparing with the warming condition. As for CS activity, acidification significantly decreased its activity in S. carolitertii whereas in S. torgalensis no significant effect was observed. These results suggest that S. carolitertii is more vulnerable to climate change, possibly as the result of its evolutionary acclimatization to milder climatic condition, while S. torgalensis evolved in the warmer Mediterranean climate. However, significant changes in HSR were observed under the combined warming and acidification (S. carolitertii) or under acidification (S. torgalensis). Our results underlie the importance of conducting experimental studies and address species endpoint responses under projected climate change scenarios to improve conservation strategies, and to safeguard endangered freshwater fish. Copyright © 2017 Elsevier Inc. All rights reserved.
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NASA Astrophysics Data System (ADS)
Rogstad, S.; Condron, A.; DeConto, R.; Pollard, D.
2017-12-01
Observational evidence indicates that the West Antarctic Ice Sheet (WAIS) is losing mass at an accelerating rate. Impacts to global climate resulting from changing ocean circulation patterns due to increased freshwater runoff from Antarctica in the future could have significant implications for global heat transport, but to-date this topic has not been investigated using complex numerical models with realistic freshwater forcing. Here, we present results from a high resolution fully coupled ocean-atmosphere model (CESM 1.2) forced with runoff from Antarctica prescribed from a high resolution regional ice sheet-ice shelf model. Results from the regional simulations indicate a potential freshwater contribution from Antarctica of up to 1 m equivalent sea level rise by the end of the century under RCP 8.5 indicating that a substantial input of freshwater into the Southern Ocean is possible. Our high resolution global simulations were performed under IPCC future climate scenarios RCP 4.5 and 8.5. We will present results showing the impact of WAIS collapse on global ocean circulation, sea ice, air temperature, and salinity in order to assess the potential for abrupt climate change triggered by WAIS collapse.
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Assessing the Nation's Brackish Groundwater Resources
NASA Astrophysics Data System (ADS)
Stanton, J.; Anning, D. W.; Moore, R. B.; McMahon, P. B.; Bohlke, J. K.; McGuire, V. L.
2014-12-01
Declines in the amount of groundwater in storage as a result of groundwater development have led to concerns about the future availability of freshwater to meet drinking-water, agricultural, industrial, and environmental needs. Industry and public drinking-water suppliers have increasingly turned to nontraditional groundwater sources, such as moderately saline (brackish) groundwater, to supplement or replace the use of freshwater. Despite the growing demand for alternative water sources, a significant potential nontraditional water resource, brackish groundwater, was last assessed almost 50 years ago. The recently (2013) initiated USGS National Brackish Groundwater Assessment, which is part of the National Water Census, will provide an updated systematic national assessment of the distribution of significant brackish groundwater resources and critical information about the hydrogeologic and chemical characterization of brackish aquifers. As part of this study, updated national-scale maps of total dissolved-solids concentrations and chemical water types will be created using data from about 400,000 sites that have been compiled from over 30 national, regional, and state sources. However, available data are biased toward freshwater and shallow systems. Preliminary analysis indicates that about 75 percent of the dissolved-solids concentrations are from freshwater aquifers, and more than 80 percent represent depths less than 500 feet below land surface. Several techniques are used to extend the information contained in the compiled data. For about half of the sites, dissolved-solids concentration was estimated from specific conductance using statistical relations. In addition, for areas where chemical data are not available, regression models are being developed to predict the occurrence of brackish groundwater based on geospatial data such as geology and other variables that are correlated to dissolved-solids concentrations.
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The future of the North American carbon cycle - projections and associated climate change
NASA Astrophysics Data System (ADS)
Huntzinger, D. N.; Chatterjee, A.; Cooley, S. R.; Dunne, J. P.; Hoffman, F. M.; Luo, Y.; Moore, D. J.; Ohrel, S. B.; Poulter, B.; Ricciuto, D. M.; Tzortziou, M.; Walker, A. P.; Mayes, M. A.
2016-12-01
Approximately half of anthropogenic emissions from the burning of fossil fuels is taken up annually by carbon sinks on the land and in the oceans. However, there are key uncertainties in how carbon uptake by terrestrial, ocean, and freshwater systems will respond to, and interact with, climate into the future. Here, we outline the current state of understanding on the future carbon budget of these major reservoirs within North America and the globe. We examine the drivers of future carbon cycle changes, including carbon-climate feedbacks, atmospheric composition, nutrient availability, and human activity and management decisions. Progress has been made at identifying vulnerabilities in carbon pools, including high-latitude permafrost, peatlands, freshwater and coastal wetlands, and ecosystems subject to disturbance events, such as insects, fire and drought. However, many of these processes/pools are not well represented in current models, and model intercomparison studies have shown a range in carbon cycle response to factors such as climate and CO2 fertilization. Furthermore, as model complexity increases, understanding the drivers of model spread becomes increasingly more difficult. As a result, uncertainties in future carbon cycle projections are large. It is also uncertain how management decisions and policies will impact future carbon stocks and flows. In order to guide policy, a better understanding of the risk and magnitude of North American carbon cycle changes is needed. This requires that future carbon cycle projections be conditioned on current observations and be reported with sufficient confidence and fully specified uncertainties.
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Future land use threats to range-restricted fish species in the United States
Januchowski-Hartley, Stephanie R.; Holtz, Lauren A.; Martinuzzi, Sebastian; ...
2016-03-04
Land use change is one major threat to freshwater biodiversity, and land use change scenarios can help to assess threats from future land use change, thereby guiding proactive conservation decisions. Furthermore, our goal was to identify which range-restricted freshwater fish species are most likely to be affected by land use change and to determine where threats to these species from future land use change in the conterminous United States are most pronounced.
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Future land use threats to range-restricted fish species in the United States
DOE Office of Scientific and Technical Information (OSTI.GOV)
Januchowski-Hartley, Stephanie R.; Holtz, Lauren A.; Martinuzzi, Sebastian
Land use change is one major threat to freshwater biodiversity, and land use change scenarios can help to assess threats from future land use change, thereby guiding proactive conservation decisions. Furthermore, our goal was to identify which range-restricted freshwater fish species are most likely to be affected by land use change and to determine where threats to these species from future land use change in the conterminous United States are most pronounced.
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Global Change and Human Consumption of Freshwater Driven by Flow Regulation and Irrigation
NASA Astrophysics Data System (ADS)
Jaramillo, F.; Destouni, G.
2015-12-01
Recent studies show major uncertainties about the magnitude and key drivers of global freshwater change, historically and projected for the future. The tackling of these uncertainties should be a societal priority to understand: 1) the role of human change drivers for freshwater availability changes, 2) the global water footprint of humanity and 3) the relation of human freshwater consumption to a proposed planetary boundary. This study analyses worldwide hydroclimatic changes, as observed during 1900-2009 in 99 large hydrological basins across all continents. We test whether global freshwater change may be driven by major developments of flow regulation and irrigation (FRI) occurring over this period. Independent categorization of the variability of FRI-impact strength among the studied basins is used to identify statistical basin differences in occurrence and strength of characteristic hydroclimatic signals of FRI. Our results show dominant signals of increasing relative evapotranspiration in basins affected by flow regulation and/or irrigation, in conjunction with decreasing relative intra-annual variability of runoff in basins affected by flow regulation. The FRI-related increase in relative evapotranspiration implies an increase of 4,688 km3/yr in global annual average water flow from land to the atmosphere. This observation-based estimate extends considerably the upper quantification limits of both FRI-driven and total global human consumption of freshwater, as well as the global water footprint of humanity. Our worldwide analysis shows clear FRI-related change signals emerging directly from observations, in spite of large change variability among basins and many other coexisting change drivers in both the atmosphere and the landscape. These results highlight the importance of considering local water use as a key change driver in Earth system studies and modelling, of relevance for global change and human consumption of freshwater.
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Water management: Current and future challenges and research directions
NASA Astrophysics Data System (ADS)
Cosgrove, William J.; Loucks, Daniel P.
2015-06-01
Water distinguishes our planet compared to all the others we know about. While the global supply of available freshwater is more than adequate to meet all current and foreseeable water demands, its spatial and temporal distributions are not. There are many regions where our freshwater resources are inadequate to meet domestic, economic development and environmental needs. In such regions, the lack of adequate clean water to meet human drinking water and sanitation needs is indeed a constraint on human health and productivity and hence on economic development as well as on the maintenance of a clean environment and healthy ecosystems. All of us involved in research must find ways to remove these constraints. We face multiple challenges in doing that, especially given a changing and uncertain future climate, and a rapidly growing population that is driving increased social and economic development, globalization, and urbanization. How best to meet these challenges requires research in all aspects of water management. Since 1965, the journal Water Resources Research has played an important role in reporting and disseminating current research related to managing the quantity and quality and cost of this resource. This paper identifies the issues facing water managers today and future research needed to better inform those who strive to create a more sustainable and desirable future.
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Water supply as a constraint on transmission expansion planning in the Western interconnection
NASA Astrophysics Data System (ADS)
Tidwell, Vincent C.; Bailey, Michael; Zemlick, Katie M.; Moreland, Barbara D.
2016-12-01
Consideration of water supply in transmission expansion planning (TEP) provides a valuable means of managing impacts of thermoelectric generation on limited water resources. Toward this opportunity, thermoelectric water intensity factors and water supply availability (fresh and non-fresh sources) were incorporated into a recent TEP exercise conducted for the electric interconnection in the Western United States. The goal was to inform the placement of new thermoelectric generation so as to minimize issues related to water availability. Although freshwater availability is limited in the West, few instances across five TEP planning scenarios were encountered where water availability impacted the development of new generation. This unexpected result was related to planning decisions that favored the development of low water use generation that was geographically dispersed across the West. These planning decisions were not made because of their favorable influence on thermoelectric water demand; rather, on the basis of assumed future fuel and technology costs, policy drivers and the topology of electricity demand. Results also projected that interconnection-wide thermoelectric water consumption would increase by 31% under the business-as-usual case, while consumption would decrease by 42% under a scenario assuming a low-carbon future. Except in a few instances, new thermoelectric water consumption could be accommodated with less than 10% of the local available water supply; however, limited freshwater supplies and state-level policies could increase use of non-fresh water sources for new thermoelectric generation. Results could have been considerably different if scenarios favoring higher-intensity water use generation technology or potential impacts of climate change had been explored. Conduct of this exercise highlighted the importance of integrating water into all phases of TEP, particularly joint management of decisions that are both directly (e.g., water availability constraint) and indirectly (technology or policy constraints) related to future thermoelectric water demand, as well as, the careful selection of scenarios that adequately bound the potential dimensions of water impact.
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Water supply as a constraint on transmission expansion planning in the Western interconnection
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tidwell, Vincent C.; Bailey, Michael; Zemlick, Katie M.
Here, consideration of water supply in transmission expansion planning (TEP) provides a valuable means of managing impacts of thermoelectric generation on limited water resources. Toward this opportunity, thermoelectric water intensity factors and water supply availability (fresh and non-fresh sources) were incorporated into a recent TEP exercise conducted for the electric interconnection in the Western United States. The goal was to inform the placement of new thermoelectric generation so as to minimize issues related to water availability. Although freshwater availability is limited in the West, few instances across five TEP planning scenarios were encountered where water availability impacted the development ofmore » new generation. This unexpected result was related to planning decisions that favored the development of low water use generation that was geographically dispersed across the West. These planning decisions were not made because of their favorable influence on thermoelectric water demand; rather, on the basis of assumed future fuel and technology costs, policy drivers and the topology of electricity demand. Results also projected that interconnection-wide thermoelectric water consumption would increase by 31% under the business-as-usual case, while consumption would decrease by 42% under a scenario assuming a low-carbon future. Except in a few instances, new thermoelectric water consumption could be accommodated with less than 10% of the local available water supply; however, limited freshwater supplies and state-level policies could increase use of non-fresh water sources for new thermoelectric generation. Results could have been considerably different if scenarios favoring higher-intensity water use generation technology or potential impacts of climate change had been explored. Conduct of this exercise highlighted the importance of integrating water into all phases of TEP, particularly joint management of decisions that are both directly (e.g., water availability constraint) and indirectly (technology or policy constraints) related to future thermoelectric water demand, as well as, the careful selection of scenarios that adequately bound the potential dimensions of water impact.« less
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Water supply as a constraint on transmission expansion planning in the Western interconnection
Tidwell, Vincent C.; Bailey, Michael; Zemlick, Katie M.; ...
2016-11-21
Here, consideration of water supply in transmission expansion planning (TEP) provides a valuable means of managing impacts of thermoelectric generation on limited water resources. Toward this opportunity, thermoelectric water intensity factors and water supply availability (fresh and non-fresh sources) were incorporated into a recent TEP exercise conducted for the electric interconnection in the Western United States. The goal was to inform the placement of new thermoelectric generation so as to minimize issues related to water availability. Although freshwater availability is limited in the West, few instances across five TEP planning scenarios were encountered where water availability impacted the development ofmore » new generation. This unexpected result was related to planning decisions that favored the development of low water use generation that was geographically dispersed across the West. These planning decisions were not made because of their favorable influence on thermoelectric water demand; rather, on the basis of assumed future fuel and technology costs, policy drivers and the topology of electricity demand. Results also projected that interconnection-wide thermoelectric water consumption would increase by 31% under the business-as-usual case, while consumption would decrease by 42% under a scenario assuming a low-carbon future. Except in a few instances, new thermoelectric water consumption could be accommodated with less than 10% of the local available water supply; however, limited freshwater supplies and state-level policies could increase use of non-fresh water sources for new thermoelectric generation. Results could have been considerably different if scenarios favoring higher-intensity water use generation technology or potential impacts of climate change had been explored. Conduct of this exercise highlighted the importance of integrating water into all phases of TEP, particularly joint management of decisions that are both directly (e.g., water availability constraint) and indirectly (technology or policy constraints) related to future thermoelectric water demand, as well as, the careful selection of scenarios that adequately bound the potential dimensions of water impact.« less
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Responses of pink salmon to CO2-induced aquatic acidification
NASA Astrophysics Data System (ADS)
Ou, Michelle; Hamilton, Trevor J.; Eom, Junho; Lyall, Emily M.; Gallup, Joshua; Jiang, Amy; Lee, Jason; Close, David A.; Yun, Sang-Seon; Brauner, Colin J.
2015-10-01
Ocean acidification negatively affects many marine species and is predicted to cause widespread changes to marine ecosystems. Similarly, freshwater ecosystems may potentially be affected by climate-change-related acidification; however, this has received far less attention. Freshwater fish represent 40% of all fishes, and salmon, which rear and spawn in freshwater, are of immense ecosystem, economical and cultural importance. In this study, we investigate the impacts of CO2-induced acidification during the development of pink salmon, in freshwater and following early seawater entry. At this critical and sensitive life stage, we show dose-dependent reductions in growth, yolk-to-tissue conversion and maximal O2 uptake capacity; as well as significant alterations in olfactory responses, anti-predator behaviour and anxiety under projected future increases in CO2 levels. These data indicate that future populations of pink salmon may be at risk without mitigation and highlight the need for further studies on the impact of CO2-induced acidification on freshwater systems.
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Groundwater availability in the United States: the value of quantitative regional assessments
Dennehy, Kevin F.; Reilly, Thomas E.; Cunningham, William L.
2015-01-01
The sustainability of water resources is under continued threat from the challenges associated with a growing population, competing demands, and a changing climate. Freshwater scarcity has become a fact in many areas. Much of the United States surface-water supplies are fully apportioned for use; thus, in some areas the only potential alternative freshwater source that can provide needed quantities is groundwater. Although frequently overlooked, groundwater serves as the principal reserve of freshwater in the US and represents much of the potential supply during periods of drought. Some nations have requirements to monitor and characterize the availability of groundwater such as the European Union’s Water Framework Directive (EPCEU 2000). In the US there is no such national requirement. Quantitative regional groundwater availability assessments, however, are essential to document the status and trends of groundwater availability for the US and make informed water-resource decisions possible now and in the future. Barthel (2014) highlighted that the value of regional groundwater assessments goes well beyond just quantifying the resource so that it can be better managed. The tools and techniques required to evaluate these unique regional systems advance the science of hydrogeology and provide enhanced methods that can benefit local-scale groundwater investigations. In addition, a significant, yet under-utilized benefit is the digital spatial and temporal data sets routinely generated as part of these studies. Even though there is no legal or regulatory requirement for regional groundwater assessments in the US, there is a logical basis for their implementation. The purpose of this essay is to articulate the rationale for and reaffirm the value of regional groundwater assessments primarily in the US; however, the arguments hold for all nations. The importance of the data sets and the methods and model development that occur as part of these assessments is stressed. These high-value data sets and models should be available in readily accessible formats for use today and in the future. Examples of advances in and accomplishments of two regional groundwater assessments are presented to demonstrate their function, relevance, and value for determining the sustainability of the groundwater resources of the US.
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Draft genome of the American Eel (Anguilla rostrata).
Pavey, Scott A; Laporte, Martin; Normandeau, Eric; Gaudin, Jérémy; Letourneau, Louis; Boisvert, Sébastien; Corbeil, Jacques; Audet, Céline; Bernatchez, Louis
2017-07-01
Freshwater eels (Anguilla sp.) have large economic, cultural, ecological and aesthetic importance worldwide, but they suffered more than 90% decline in global stocks over the past few decades. Proper genetic resources, such as sequenced, assembled and annotated genomes, are essential to help plan sustainable recoveries by identifying physiological, biochemical and genetic mechanisms that caused the declines or that may lead to recoveries. Here, we present the first sequenced genome of the American eel. This genome contained 305 043 contigs (N50 = 7397) and 79 209 scaffolds (N50 = 86 641) for a total size of 1.41 Gb, which is in the middle of the range of previous estimations for this species. In addition, protein-coding regions, including introns and flanking regions, are very well represented in the genome, as 95.2% of the 458 core eukaryotic genes and 98.8% of the 248 ultra-conserved subset were represented in the assembly and a total of 26 564 genes were annotated for future functional genomics studies. We performed a candidate gene analysis to compare three genes among all three freshwater eel species and, congruent with the phylogenetic relationships, Japanese eel (A. japanica) exhibited the most divergence. Overall, the sequenced genome presented in this study is a crucial addition to the presently available genetic tools to help guide future conservation efforts of freshwater eels. © 2016 John Wiley & Sons Ltd.
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Groundwater resources of Mosteiros basin, island of Fogo, Cape Verde, West Africa
Heilweil, Victor M.; Gingerich, Stephen B.; Plummer, Niel; Verstraeten, Ingrid M.
2010-01-01
Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.
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NASA Astrophysics Data System (ADS)
Czajkowski, Jeffrey; Villarini, Gabriele; Montgomery, Marilyn; Michel-Kerjan, Erwann; Goska, Radoslaw
2017-02-01
The most recent decades have witnessed record breaking losses associated with U.S. landfalling tropical cyclones (TCs). Flood-related damages represent a large portion of these losses, and although storm surge is typically the main focus in the media and of warnings, much of the TC flood losses are instead freshwater-driven, often extending far inland from the landfall locations. Despite this actuality, knowledge of TC freshwater flood risk is still limited. Here we provide for the first time a comprehensive assessment of the TC freshwater flood risk from the full set of all significant flood events associated with U.S. landfalling TCs from 2001 to 2014. We find that the areas impacted by freshwater flooding are nearly equally divided between coastal and inland areas. We determine the statistical relationship between physical hazard and residential economic impact at a community level for the entire country. These results allow us to assess the potential future changes in TC freshwater flood risk due to changing climate pattern and urbanization in a more heavily populated U.S. Findings have important implications for flood risk management, insurance and resilience.
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Czajkowski, Jeffrey; Villarini, Gabriele; Montgomery, Marilyn; Michel-Kerjan, Erwann; Goska, Radoslaw
2017-01-01
The most recent decades have witnessed record breaking losses associated with U.S. landfalling tropical cyclones (TCs). Flood-related damages represent a large portion of these losses, and although storm surge is typically the main focus in the media and of warnings, much of the TC flood losses are instead freshwater-driven, often extending far inland from the landfall locations. Despite this actuality, knowledge of TC freshwater flood risk is still limited. Here we provide for the first time a comprehensive assessment of the TC freshwater flood risk from the full set of all significant flood events associated with U.S. landfalling TCs from 2001 to 2014. We find that the areas impacted by freshwater flooding are nearly equally divided between coastal and inland areas. We determine the statistical relationship between physical hazard and residential economic impact at a community level for the entire country. These results allow us to assess the potential future changes in TC freshwater flood risk due to changing climate pattern and urbanization in a more heavily populated U.S. Findings have important implications for flood risk management, insurance and resilience. PMID:28148952
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The Differential Warming Response of Britain’s Rivers (1982–2011)
Jonkers, Art R. T.; Sharkey, Kieran J.
2016-01-01
River water temperature is a hydrological feature primarily controlled by topographical, meteorological, climatological, and anthropogenic factors. For Britain, the study of freshwater temperatures has focussed mainly on observations made in England and Wales; similar comprehensive data sets for Scotland are currently unavailable. Here we present a model for the whole of mainland Britain over three recent decades (1982–2011) that incorporates geographical extrapolation to Scotland. The model estimates daily mean freshwater temperature for every river segment and for any day in the studied period, based upon physico-geographical features, daily mean air and sea temperatures, and available freshwater temperature measurements. We also extrapolate the model temporally to predict future warming of Britain’s rivers given current observed trends. Our results highlight the spatial and temporal diversity of British freshwater temperatures and warming rates. Over the studied period, Britain’s rivers had a mean temperature of 9.84°C and experienced a mean warming of +0.22°C per decade, with lower rates for segments near lakes and in coastal regions. Model results indicate April as the fastest-warming month (+0.63°C per decade on average), and show that most rivers spend on average ever more days of the year at temperatures exceeding 10°C, a critical threshold for several fish pathogens. Our results also identify exceptional warming in parts of the Scottish Highlands (in April and September) and pervasive cooling episodes, in December throughout Britain and in July in the southwest of England (in Wales, Cornwall, Devon, and Dorset). This regional heterogeneity in rates of change has ramifications for current and future water quality, aquatic ecosystems, as well as for the spread of waterborne diseases. PMID:27832108
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The Differential Warming Response of Britain's Rivers (1982-2011).
Jonkers, Art R T; Sharkey, Kieran J
2016-01-01
River water temperature is a hydrological feature primarily controlled by topographical, meteorological, climatological, and anthropogenic factors. For Britain, the study of freshwater temperatures has focussed mainly on observations made in England and Wales; similar comprehensive data sets for Scotland are currently unavailable. Here we present a model for the whole of mainland Britain over three recent decades (1982-2011) that incorporates geographical extrapolation to Scotland. The model estimates daily mean freshwater temperature for every river segment and for any day in the studied period, based upon physico-geographical features, daily mean air and sea temperatures, and available freshwater temperature measurements. We also extrapolate the model temporally to predict future warming of Britain's rivers given current observed trends. Our results highlight the spatial and temporal diversity of British freshwater temperatures and warming rates. Over the studied period, Britain's rivers had a mean temperature of 9.84°C and experienced a mean warming of +0.22°C per decade, with lower rates for segments near lakes and in coastal regions. Model results indicate April as the fastest-warming month (+0.63°C per decade on average), and show that most rivers spend on average ever more days of the year at temperatures exceeding 10°C, a critical threshold for several fish pathogens. Our results also identify exceptional warming in parts of the Scottish Highlands (in April and September) and pervasive cooling episodes, in December throughout Britain and in July in the southwest of England (in Wales, Cornwall, Devon, and Dorset). This regional heterogeneity in rates of change has ramifications for current and future water quality, aquatic ecosystems, as well as for the spread of waterborne diseases.
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Asquith, W.H.; Mosier, J. G.; Bush, P.W.
1997-01-01
The watershed simulation model Hydrologic Simulation Program—Fortran (HSPF) was used to generate simulated flow (runoff) from the 13 watersheds to the six bay systems because adequate gaged streamflow data from which to estimate freshwater inflows are not available; only about 23 percent of the adjacent contributing watershed area is gaged. The model was calibrated for the gaged parts of three watersheds—that is, selected input parameters (meteorologic and hydrologic properties and conditions) that control runoff were adjusted in a series of simulations until an adequate match between model-generated flows and a set (time series) of gaged flows was achieved. The primary model input is rainfall and evaporation data and the model output is a time series of runoff volumes. After calibration, simulations driven by daily rainfall for a 26-year period (1968–93) were done for the 13 watersheds to obtain runoff under current (1983–93), predevelopment (pre-1940 streamflow and pre-urbanization), and future (2010) land-use conditions for estimating freshwater inflows and for comparing runoff under the three land-use conditions; and to obtain time series of runoff from which to estimate time series of freshwater inflows for trend analysis.
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Pfrender, M.E.; Ferrington, L.C.; Hawkins, C.P.; Hartzell, P.L.; Bagley, M.; Jackson, S.; Courtney, G.W.; Larsen, D.P.; Creutzburg, B.R.; Levesque, C.A.; Epler, J.H.; Morse, J.C.; Fend, S.; Petersen, M.J.; Ruiter, D.; Schindel, D.; Whiting, M.
2010-01-01
Assessing the biodiversity of macroinvertebrate fauna in freshwater ecosystems is an essential component of both basic ecological inquiry and applied ecological assessments. Aspects of taxonomic diversity and composition in freshwater communities are widely used to quantify water quality and measure the efficacy of remediation and restoration efforts. The accuracy and precision of biodiversity assessments based on standard morphological identifications are often limited by taxonomic resolution and sample size. Morphologically based identifications are laborious and costly, significantly constraining the sample sizes that can be processed. We suggest that the development of an assay platform based on DNA signatures will increase the precision and ease of quantifying biodiversity in freshwater ecosystems. Advances in this area will be particularly relevant for benthic and planktonic invertebrates, which are often monitored by regulatory agencies. Adopting a genetic assessment platform will alleviate some of the current limitations to biodiversity assessment strategies. We discuss the benefits and challenges associated with DNA-based assessments and the methods that are currently available. As recent advances in microarray and next-generation sequencing technologies will facilitate a transition to DNA-based assessment approaches, future research efforts should focus on methods for data collection, assay platform development, establishing linkages between DNA signatures and well-resolved taxonomies, and bioinformatics. ?? 2010 by The University of Chicago Press.
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Long-term chloride concentrations in North American and European freshwater lakes
Dugan, Hilary A.; Summers, Jamie C.; Skaff, Nicholas K.; Krivak-Tetley, Flora E.; Doubek, Jonathan P.; Burke, Samantha M.; Bartlett, Sarah L.; Arvola, Lauri; Jarjanazi, Hamdi; Korponai, János; Kleeberg, Andreas; Monet, Ghislaine; Monteith, Don; Moore, Karen; Rogora, Michela; Hanson, Paul C.; Weathers, Kathleen C.
2017-01-01
Anthropogenic sources of chloride in a lake catchment, including road salt, fertilizer, and wastewater, can elevate the chloride concentration in freshwater lakes above background levels. Rising chloride concentrations can impact lake ecology and ecosystem services such as fisheries and the use of lakes as drinking water sources. To analyze the spatial extent and magnitude of increasing chloride concentrations in freshwater lakes, we amassed a database of 529 lakes in Europe and North America that had greater than or equal to ten years of chloride data. For each lake, we calculated climate statistics of mean annual total precipitation and mean monthly air temperatures from gridded global datasets. We also quantified land cover metrics, including road density and impervious surface, in buffer zones of 100 to 1,500 m surrounding the perimeter of each lake. This database represents the largest global collection of lake chloride data. We hope that long-term water quality measurements in areas outside Europe and North America can be added to the database as they become available in the future. PMID:28786983
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Long-term chloride concentrations in North American and European freshwater lakes.
Dugan, Hilary A; Summers, Jamie C; Skaff, Nicholas K; Krivak-Tetley, Flora E; Doubek, Jonathan P; Burke, Samantha M; Bartlett, Sarah L; Arvola, Lauri; Jarjanazi, Hamdi; Korponai, János; Kleeberg, Andreas; Monet, Ghislaine; Monteith, Don; Moore, Karen; Rogora, Michela; Hanson, Paul C; Weathers, Kathleen C
2017-08-08
Anthropogenic sources of chloride in a lake catchment, including road salt, fertilizer, and wastewater, can elevate the chloride concentration in freshwater lakes above background levels. Rising chloride concentrations can impact lake ecology and ecosystem services such as fisheries and the use of lakes as drinking water sources. To analyze the spatial extent and magnitude of increasing chloride concentrations in freshwater lakes, we amassed a database of 529 lakes in Europe and North America that had greater than or equal to ten years of chloride data. For each lake, we calculated climate statistics of mean annual total precipitation and mean monthly air temperatures from gridded global datasets. We also quantified land cover metrics, including road density and impervious surface, in buffer zones of 100 to 1,500 m surrounding the perimeter of each lake. This database represents the largest global collection of lake chloride data. We hope that long-term water quality measurements in areas outside Europe and North America can be added to the database as they become available in the future.
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Sustainable water management under future uncertainty with eco-engineering decision scaling
NASA Astrophysics Data System (ADS)
Poff, N. Leroy; Brown, Casey M.; Grantham, Theodore E.; Matthews, John H.; Palmer, Margaret A.; Spence, Caitlin M.; Wilby, Robert L.; Haasnoot, Marjolijn; Mendoza, Guillermo F.; Dominique, Kathleen C.; Baeza, Andres
2016-01-01
Managing freshwater resources sustainably under future climatic and hydrological uncertainty poses novel challenges. Rehabilitation of ageing infrastructure and construction of new dams are widely viewed as solutions to diminish climate risk, but attaining the broad goal of freshwater sustainability will require expansion of the prevailing water resources management paradigm beyond narrow economic criteria to include socially valued ecosystem functions and services. We introduce a new decision framework, eco-engineering decision scaling (EEDS), that explicitly and quantitatively explores trade-offs in stakeholder-defined engineering and ecological performance metrics across a range of possible management actions under unknown future hydrological and climate states. We illustrate its potential application through a hypothetical case study of the Iowa River, USA. EEDS holds promise as a powerful framework for operationalizing freshwater sustainability under future hydrological uncertainty by fostering collaboration across historically conflicting perspectives of water resource engineering and river conservation ecology to design and operate water infrastructure for social and environmental benefits.
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Sustainable water management under future uncertainty with eco-engineering decision scaling
Poff, N LeRoy; Brown, Casey M; Grantham, Theodore E.; Matthews, John H; Palmer, Margaret A.; Spence, Caitlin M; Wilby, Robert L.; Haasnoot, Marjolijn; Mendoza, Guillermo F; Dominique, Kathleen C; Baeza, Andres
2015-01-01
Managing freshwater resources sustainably under future climatic and hydrological uncertainty poses novel challenges. Rehabilitation of ageing infrastructure and construction of new dams are widely viewed as solutions to diminish climate risk, but attaining the broad goal of freshwater sustainability will require expansion of the prevailing water resources management paradigm beyond narrow economic criteria to include socially valued ecosystem functions and services. We introduce a new decision framework, eco-engineering decision scaling (EEDS), that explicitly and quantitatively explores trade-offs in stakeholder-defined engineering and ecological performance metrics across a range of possible management actions under unknown future hydrological and climate states. We illustrate its potential application through a hypothetical case study of the Iowa River, USA. EEDS holds promise as a powerful framework for operationalizing freshwater sustainability under future hydrological uncertainty by fostering collaboration across historically conflicting perspectives of water resource engineering and river conservation ecology to design and operate water infrastructure for social and environmental benefits.
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Acute toxicity and effects analysis of endosulfan sulfate to freshwater fish species.
Carriger, John F; Hoang, Tham C; Rand, Gary M; Gardinali, Piero R; Castro, Joffre
2011-02-01
Endosulfan sulfate is a persistent environmental metabolite of endosulfan, an organochlorine insecticide-acaricide presently registered by the United States Environmental Protection Agency. There is, however, limited acute fish toxicity data for endosulfan sulfate. This study determines the acute toxicity (LC₅₀s and LC₁₀s) of endosulfan sulfate to three inland Florida native fish species (mosquitofish [Gambusia affinis]; least killifish [Heterandria formosa]; and sailfin mollies [Poecilia latipinna]) as well as fathead minnows (Pimephales promelas). Ninety-six-h acute toxicity tests were conducted with each fish species under flow-through conditions. For all of the above-mentioned fish species, 96-h LC₅₀ estimates ranged from 2.1 to 3.5 μg/L endosulfan sulfate. The 96-h LC₁₀ estimates ranged from 0.8 to 2.1 μg/L endosulfan sulfate. Of all of the fish tested, the least killifish appeared to be the most sensitive to endosulfan sulfate exposure. The above-mentioned data were combined with previous acute toxicity data for endosulfan sulfate and freshwater fish for an effects analysis. The effects analysis estimated hazardous concentrations expected to exceed 5, 10, and 50% of the fish species' acute LC₅₀ or LC₁₀ values (HC₅, HC₁₀, and HC₅₀). The endosulfan sulfate freshwater-fish acute tests were also compared with the available freshwater-fish acute toxicity data for technical endosulfan. Technical endosulfan is a mixture of α- and β-endosulfan. The LC₅₀s had a wider range for technical endosulfan, and their distribution produced a lower HC₁₀ than for endosulfan sulfate. The number of freshwater-fish LC₅₀s for endosulfan sulfate is much smaller than the number available for technical endosulfan, reflecting priorities in examining the toxicity of the parent compounds of pesticides. The toxicity test results and effects analyses provided acute effect values for endosulfan sulfate and freshwater fish that might be applied in future screening level ecologic risk assessments. The effects analyses also discussed several deficiencies in conventional methods for setting water-quality criteria and determining ecologic effects from acute toxicity tests.
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Misut, Paul E.; Schubert, Christopher E.; Bova, Richard G.; Colabufo, Steven R.
2004-01-01
Ground water is the sole source of freshwater on the North Fork of Long Island. Future demands for the limited freshwater supply during a prolonged drought could cause drawdowns that induce saltwater intrusion and render the supply unusable. The freshwater system on the North Fork contains several localized, hydraulically isolated aquifers bounded by salty water. The need for information on the ability of these aquifers to meet future demands prompted a 4-year study to develop a ground-water flow model to simulate several proposed pumping scenarios under long-term average conditions and during a hypothetical drought, and to delineate the resulting ground-water levels and movement of the freshwater-saltwater interface. The model code selected was SHARP, a quasi-three-dimensional finite-difference method of simulating freshwater and saltwater flow simultaneously.Two sets of four proposed pumping scenarios were evaluated. The first represented average recharge from precipitation during 2006-20; the second represented the same period and conditions except for a 5-year period of drought conditions. The average-recharge simulations used the long-term (1959-99) rate of recharge; the drought simulations applied a 20-percent reduction in recharge rate and a 20-percent increase in the 1999 rate of agricultural pumpage during 2011–15.The simulated movement of the freshwater-saltwater interface in future withdrawal and recharge scenarios indicates that the interface may rise beneath pumped wells at Inlet Drive, Brecknock Hall, Main Bayview Road, Islands End, North Road, and Alvah's Lane. Either (1) movement of the interface to within 50 feet of the well screen, (2) a large percent change in the distance between the interface and the well screen, or (3) movement of the interface through a clay layer is a cause for concern. Wellfields in which saltwater intrusion does not appear to be a cause for concern were those at Ackerly Pond, Kenney's Road, Middle Road, Rocky Point Road, and hypothetical sites where future wellfields have been proposed.
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Groundwater resources of Ribeira Paúl basin, island of Santo Antão, Cape Verde, West Africa
Heilweil, Victor M.; Gingerich, Stephen B.; Verstraeten, Ingrid M.
2010-01-01
Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.
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Groundwater resources of Ribeira Fajã basin, island of São Nicolau, Cape Verde, West Africa
Heilweil, Victor M.; Gingerich, Stephen B.; Plummer, Niel; Verstraeten, Ingrid M.
2010-01-01
Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.
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Enhancing protection for vulnerable waters
Governments worldwide do not adequately protect their limited freshwater systems and therefore place freshwater functions and attendant ecosystem services at risk. The best available scientific evidence compels enhanced protections for freshwater systems, especially for impermane...
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Modeling impacts of climate change on freshwater availability in Africa
NASA Astrophysics Data System (ADS)
Faramarzi, Monireh; Abbaspour, Karim C.; Ashraf Vaghefi, Saeid; Farzaneh, Mohammad Reza; Zehnder, Alexander J. B.; Srinivasan, Raghavan; Yang, Hong
2013-02-01
SummaryThis study analyzes the impact of climate change on freshwater availability in Africa at the subbasin level for the period of 2020-2040. Future climate projections from five global circulation models (GCMs) under the four IPCC emission scenarios were fed into an existing SWAT hydrological model to project the impact on different components of water resources across the African continent. The GCMs have been downscaled based on observed data of Climate Research Unit to represent local climate conditions at 0.5° grid spatial resolution. The results show that for Africa as a whole, the mean total quantity of water resources is likely to increase. For individual subbasins and countries, variations are substantial. Although uncertainties are high in the simulated results, we found that in many regions/countries, most of the climate scenarios projected the same direction of changes in water resources, suggesting a relatively high confidence in the projections. The assessment of the number of dry days and the frequency of their occurrences suggests an increase in the drought events and their duration in the future. Overall, the dry regions have higher uncertainties than the wet regions in the projected impacts on water resources. This poses additional challenge to the agriculture in dry regions where water shortage is already severe while irrigation is expected to become more important to stabilize and increase food production.
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Consequences of Groundwater Development on Water Resources of Hawai`i
NASA Astrophysics Data System (ADS)
Rotzoll, K.; Izuka, S. K.; El-Kadi, A. I.
2017-12-01
The availability of fresh groundwater for human use is limited by whether the impacts of withdrawals are deemed acceptable by community stakeholders and water-resource managers. Quantifying the island-wide hydrologic impacts of withdrawal—saltwater intrusion, water-table decline, and reduction of groundwater discharge to streams, nearshore environments and downgradient groundwater bodies—is thus a key step for assessing fresh groundwater availability in Hawai`i. Groundwater-flow models of the individual islands of Kaua`i, O`ahu, and Maui were constructed using MODFLOW 2005 with the Seawater-Intrusion Package (SWI2). Consistent model construction among the islands, calibration, and analysis were streamlined using Python scripts. Results of simulating historical withdrawals from Hawai`i's volcanic aquifers show that the types and magnitudes of impacts that can limit fresh groundwater availability vary among each islands' unique hydrogeologic settings. In high-permeability freshwater-lens aquifers, saltwater intrusion and reductions in coastal groundwater discharge are the principal consequences of withdrawals that can limit groundwater availability. In dike-impounded groundwater and thickly saturated low-permeability aquifers, reduced groundwater discharge to streams, water-table decline, or reduced flows to adjacent freshwater-lens aquifers can limit fresh groundwater availability. The numerical models are used to quantify and delineate the spatial distribution of these impacts for the three islands. The models were also used to examine how anticipated changes in groundwater recharge and withdrawals will affect fresh groundwater availability in the future.
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Luangpipat, Tiyaporn; Chisti, Yusuf
2017-09-10
Five nominally freshwater microalgae (Chlorella vulgaris, Choricystis minor, Neochloris sp., Pseudococcomyxa simplex, Scenedesmus sp.) with a known ability to produce high-levels of lipids for possible use as fuel oils were evaluated for their ability to thrive and produce lipids in seawater and brackish water. Only C. vulgaris was found to thrive and produce lipids in full strength seawater. Seawater tolerant strains of C. vulgaris are unusual. Lipid productivity in nutrient sufficient seawater exceeded 37mgL -1 d -1 and was nearly 2-fold greater than in freshwater. Although other microalgae such as C. minor had higher lipid productivities (e.g. 45mgL -1 d -1 ), they did not thrive in seawater. The lipid content of the C. vulgaris biomass was nearly 16% by dry weight. The calorific value of the seawater-grown C. vulgaris biomass exceeded 25kJg -1 . Compared to continuously illuminated cultures, a 12/12h light-dark cycle reduced lipid productivity of C. vulgaris by ∼30%, but did not affect the lipid content of the biomass. Biomass yield on phosphate was nearly 27% higher in seawater compared to in freshwater. While C. vulgaris has been extensively studied in freshwater, it has not been examined to any detail in full strength seawater. Studies in seawater are essential for any future large scale production of algal oils for biofuels: seawater is available cheaply and in large amounts whereas there is a global shortage of freshwater. Copyright © 2016 Elsevier B.V. All rights reserved.
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Leduc, Antoine O. H. C.; Munday, Philip L.; Brown, Grant E.; Ferrari, Maud C. O.
2013-01-01
For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory-mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2 with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2 levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2 levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices. PMID:23980246
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Leduc, Antoine O H C; Munday, Philip L; Brown, Grant E; Ferrari, Maud C O
2013-01-01
For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Whereas the ecological impacts of impaired olfactory-mediated behaviour may be similar between freshwater and marine ecosystems, the underlying mechanisms are quite distinct. In acidified freshwater, molecular change to chemical cues along with reduced olfaction sensitivity appear to be the primary causes of olfactory-mediated behavioural impairment. By contrast, experiments simulating future ocean acidification suggest that interference of high CO2 with brain neurotransmitter function is the primary cause for olfactory-mediated behavioural impairment in fish. Different physico-chemical characteristics between marine and freshwater systems are probably responsible for these distinct mechanisms of impairment, which, under globally rising CO2 levels, may lead to strikingly different consequences to olfaction. While fluctuations in pH may occur in both freshwater and marine ecosystems, marine habitat will remain alkaline despite future ocean acidification caused by globally rising CO2 levels. In this synthesis, we argue that ecosystem-specific mechanisms affecting olfaction need to be considered for effective management and conservation practices.
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Governance conditions for adaptive freshwater management in the Vietnamese Mekong Delta
NASA Astrophysics Data System (ADS)
Ha, T. P.; Dieperink, Carel; Dang Tri, Van Pham; Otter, Henriëtte S.; Hoekstra, Piet
2018-02-01
The Vietnamese Mekong Delta (VMD) is a region of utmost importance to Vietnam's national food security. However, the availability of required freshwater resources (from both surface and groundwater sources) is currently under great threats due to dry season salinity intrusion, surface water pollution, and over-exploitation of groundwater. Global climate change, sea level rise, and upstream and in situ development activities may worsen the situation. Assuming that adaptive management could be a promising strategy to address the increasingly complex and unpredictable water-related problems in the VMD, we design and apply a framework to identify the extent to which the governance regime in this region exhibits conditions that are likely to promote adaptive freshwater management. Using both primary and secondary data, our analysis reveals that the prospects for adaptive water management in the study area are limited since several conditions were not present. We observe among others limitations in vertical and horizontal integration and public participation, restraints in knowledge and information sharing, inadequate policy development and implementation, and insufficient diversification of financial resources. Following our findings, we conclude the paper with recommendations both for national, regional and local policy interventions and for future research.
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The Impacts of Modern Warfare on Freshwater Ecosystems
NASA Astrophysics Data System (ADS)
Francis, Robert A.
2011-11-01
There is increasing recognition and concern regarding the impacts of modern industrial warfare on the environment. Freshwater ecosystems are perhaps the most vulnerable to warfare-related impacts, which is of concern given that they provide so many essential environmental resources and services to society. Despite this, there has been little work to establish and quantify the types of impacts (both negative and positive) that warfare may have on such systems. This paper firstly highlights why rivers and lakes may be susceptible to warfare-related impacts, before synthesizing the available literature to explore the following main themes: intensification of wartime resource acquisition, use of water as an offensive or defensive weapon, direct and indirect effects of explosive ordnance, increased pollution, introduction of invasive alien species, and positive ecological impacts. This is then followed by a discussion of the implications of such impacts in relation to future warfare, including a consideration of the efficacy of existing legal instruments to protect the environment during conflict, and the trend for war to become more localized and `informal', and therefore less regulated. Finally, the paper identifies key research foci for understanding and mitigating the effects of warfare on freshwater ecosystems.
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Sustaining healthy freshwater ecosystems
Baron, Jill S.; Poff, N.L.
2004-01-01
Functionally intact and biologically complex freshwater ecosystems provide many economically valuable commodities and services to society. The services supplied by freshwater ecosystems include flood control, transportation, recreation, purification of human and industrial wastes, habitat for plants and animals, and production of fish and other foods and marketable goods. These human benefits are called ecological services, defined as “the conditions and processes through which natural ecosystems, and the species that make them up, sustain and fulfill human life” (Daily 1997). Over the long term, healthy freshwater ecosystems are likely to retain the adaptive capacity to sustain production of these ecological services in the face of future environmental disruptions such as climate change.
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Freshwater Education: The Need, The Tools, and The "Vital Link."
ERIC Educational Resources Information Center
Shroeder, Linda
1984-01-01
Freshwater education programs are beginning to instill in young people a sense of awareness and a sense of responsibility regarding the future of water resources. Several of these programs are discussed, including Project COAST (Coastal, Oceanic, and Aquatic Studies) and "Acid Precipitation Learning Materials, Grades 7-12." (JN)
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The consequences of tourism for sustainable water use on a tropical island: Zanzibar, Tanzania.
Gössling, S
2001-02-01
Many developing countries in the tropics have focused on tourism to generate additional income sources and to diversity the economy. Coastlines in particular have been on the forefront of tourist infrastructure development. Here, the presence of a large number of tourists has often had negative consequences for the sustainable use of the available resources, which in turn has had an effect on the integrity of the ecosystems. In this paper, the situation is described for the use of freshwater resources on the east coast of Zanzibar, Tanzania. This region is water poor, relying on freshwater derived from seasonal rains and stored in less efficient aquifers, which consist of freshwater lenses floating on the underlying seawater. Tourism in the area has grown rapidly in recent years and is expected to further increase in the future. This development is expected to put additional pressure on the freshwater resources of the east coast, which show already signs of over-use. The consequences of overexploitation can include the lowering of the groundwater table, land subsidence, deteriorating groundwater quality, and saltwater intrusion. These, in turn, determine the living conditions in coastal areas and the effects will be felt both by the local populations and the tourist industry. An investigation is made into the causes and consequences of water abstraction by the tourist industry. The results show that present levels of withdrawal are not sustainable, and parts of the local populations are already experiencing water deficits on a daily basis. In the future, if the expected increase in tourist numbers occurs, the pressure on the aquifers will correspondingly increase. The results could be that the tourism in the area becomes unsustainable, which could have an adverse effect on the national economy and also on the local population and environment. Therefore, a precautionary water-management approach is suggested.
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Davis, Jenny; Pavlova, Alexandra; Thompson, Ross; Sunnucks, Paul
2013-01-01
Refugia have been suggested as priority sites for conservation under climate change because of their ability to facilitate survival of biota under adverse conditions. Here, we review the likely role of refugial habitats in conserving freshwater biota in arid Australian aquatic systems where the major long-term climatic influence has been aridification. We introduce a conceptual model that characterizes evolutionary refugia and ecological refuges based on our review of the attributes of aquatic habitats and freshwater taxa (fishes and aquatic invertebrates) in arid Australia. We also identify methods of recognizing likely future refugia and approaches to assessing the vulnerability of arid-adapted freshwater biota to a warming and drying climate. Evolutionary refugia in arid areas are characterized as permanent, groundwater-dependent habitats (subterranean aquifers and springs) supporting vicariant relicts and short-range endemics. Ecological refuges can vary across space and time, depending on the dispersal abilities of aquatic taxa and the geographical proximity and hydrological connectivity of aquatic habitats. The most important are the perennial waterbodies (both groundwater and surface water fed) that support obligate aquatic organisms. These species will persist where suitable habitats are available and dispersal pathways are maintained. For very mobile species (invertebrates with an aerial dispersal phase) evolutionary refugia may also act as ecological refuges. Evolutionary refugia are likely future refugia because their water source (groundwater) is decoupled from local precipitation. However, their biota is extremely vulnerable to changes in local conditions because population extinction risks cannot be abated by the dispersal of individuals from other sites. Conservation planning must incorporate a high level of protection for aquifers that support refugial sites. Ecological refuges are vulnerable to changes in regional climate because they have little thermal or hydrological buffering. Accordingly, conservation planning must focus on maintaining meta-population processes, especially through dynamic connectivity between aquatic habitats at a landscape scale. PMID:23526791
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Davis, Jenny; Pavlova, Alexandra; Thompson, Ross; Sunnucks, Paul
2013-07-01
Refugia have been suggested as priority sites for conservation under climate change because of their ability to facilitate survival of biota under adverse conditions. Here, we review the likely role of refugial habitats in conserving freshwater biota in arid Australian aquatic systems where the major long-term climatic influence has been aridification. We introduce a conceptual model that characterizes evolutionary refugia and ecological refugees based on our review of the attributes of aquatic habitats and freshwater taxa (fishes and aquatic invertebrates) in arid Australia. We also identify methods of recognizing likely future refugia and approaches to assessing the vulnerability of arid-adapted freshwater biota to a warming and drying climate. Evolutionary refugia in arid areas are characterized as permanent, groundwater-dependent habitats (subterranean aquifers and springs) supporting vicariant relicts and short-range endemics. Ecological refugees can vary across space and time, depending on the dispersal abilities of aquatic taxa and the geographical proximity and hydrological connectivity of aquatic habitats. The most important are the perennial waterbodies (both groundwater and surface water fed) that support obligate aquatic organisms. These species will persist where suitable habitats are available and dispersal pathways are maintained. For very mobile species (invertebrates with an aerial dispersal phase) evolutionary refugia may also act as ecological refugees. Evolutionary refugia are likely future refugia because their water source (groundwater) is decoupled from local precipitation. However, their biota is extremely vulnerable to changes in local conditions because population extinction risks cannot be abated by the dispersal of individuals from other sites. Conservation planning must incorporate a high level of protection for aquifers that support refugial sites. Ecological refuges are vulnerable to changes in regional climate because they have little thermal or hydrological buffering. Accordingly, conservation planning must focus on maintaining meta-population processes, especially through dynamic connectivity between aquatic habitats at a landscape scale. © 2013 Blackwell Publishing Ltd.
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Phytoplankton Assemblages in Selected Freshwaters of New Jersey
NASA Astrophysics Data System (ADS)
Caraballo, Y. A.; Wu, M. S.
2017-12-01
Characterizing phytoplankton assemblages in freshwaters is crucial for future management and monitoring of drinking and recreational freshwaters of New Jersey. New Jersey freshwater phytoplankton assemblages are poorly known and there is no list of freshwater phytoplankton taxa in New Jersey. This study seeks to describe phytoplankton assemblages of freshwaters in New Jersey. Results will help address public health, economic and environmental threats related to harmful algal blooms in New Jersey. A total of 49 freshwater sites, including ponds, rivers and reservoirs, were used for this study. Overall results showed 66 taxa of freshwater phytoplankton in 6 major groups and 29 different orders. Green algae had the highest number of taxa, followed by diatoms and blue-greens (cyanobacteria). The most common freshwater taxa in NJ are Synedra spp., Fragilaria spp., Selenastrum capricornutum, Scenedesmus spp., and Anabaena spp. Cyanobacteria species are present in more than half of the sites examined in this study. All ten cyanobacteria taxa present in New Jersey freshwaters are capable of producing the endotoxin lipopolysaccharides (LPS), eight can produce the hepatotoxins and six can produce neutoroxins. In addition, some taxa such as Anabaena spp. are capable of simultaneously producing endotoxins, hepatotoxins, neurotoxins and taste and odor compounds. The presence of taxa capable of producing multiple toxins infers the difficulty of management and treatment as well as increased public health effects.
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Flitcroft, Rebecca; Burnett, Kelly; Christiansen, Kelly
2013-07-01
Diadromous aquatic species that cross a diverse range of habitats (including marine, estuarine, and freshwater) face different effects of climate change in each environment. One such group of species is the anadromous Pacific salmon (Oncorhynchus spp.). Studies of the potential effects of climate change on salmonids have focused on both marine and freshwater environments. Access to a variety of estuarine habitat has been shown to enhance juvenile life-history diversity, thereby contributing to the resilience of many salmonid species. Our study is focused on the effect of sea-level rise on the availability, complexity, and distribution of estuarine, and low-freshwater habitat for Chinook salmon (Oncorhynchus tshawytscha), steelhead (anadromous O. mykiss), and coho salmon (O. kisutch) along the Oregon Coast under future climate change scenarios. Using LiDAR, we modeled the geomorphologies of five Oregon estuaries and estimated a contour associated with the current mean high tide. Contour intervals at 1- and 2-m increments above the current mean high tide were generated, and changes in the estuary morphology were assessed. Because our analysis relied on digital data, we compared three types of digital data in one estuary to assess the utility of different data sets in predicting the changes in estuary shape. For each salmonid species, changes in the amount and complexity of estuarine edge habitats varied by estuary. The simple modeling approach we applied can also be used to identify areas that may be most amenable to pre-emptive restoration actions to mitigate or enhance salmonid habitat under future climatic conditions.
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Implications of climate change for potamodromous fishes.
Beatty, Stephen J; Morgan, David L; Lymbery, Alan J
2014-06-01
There is little understanding of how climate change will impact potamodromous freshwater fishes. Since the mid 1970s, a decline in annual rainfall in south-western Australia (a globally recognized biodiversity hotspot) has resulted in the rivers of the region undergoing severe reductions in surface flows (ca. 50%). There is universal agreement amongst Global Climate Models that rainfall will continue to decline in this region. Limited data are available on the movement patterns of the endemic freshwater fishes of south-western Australia or on the relationship between their life histories and hydrology. We used this region as a model to determine how dramatic hydrological change may impact potamodromous freshwater fishes. Migration patterns of fishes in the largest river in south-western Australia were quantified over a 4 year period and were related to a number of key environmental variables including discharge, temperature, pH, conductivity and dissolved oxygen. Most of the endemic freshwater fishes were potamodromous, displaying lateral seasonal spawning migrations from the main channel into tributaries, and there were significant temporal differences in movement patterns between species. Using a model averaging approach, amount of discharge was clearly the best predictor of upstream and downstream movement for most species. Given past and projected reductions in surface flow and groundwater, the findings have major implications for future recruitment rates and population viabilities of potamodromous fishes. Freshwater ecosystems in drying climatic regions can only be managed effectively if such hydro-ecological relationships are considered. Proactive management and addressing existing anthropogenic stressors on aquatic ecosystems associated with the development of surface and groundwater resources and land use is required to increase the resistance and resilience of potamodromous fishes to ongoing flow reductions. © 2013 John Wiley & Sons Ltd.
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Jung, Hyungtaek; Yoon, Byung-Ha; Kim, Woo-Jin; Kim, Dong-Wook; Hurwood, David A; Lyons, Russell E; Salin, Krishna R; Kim, Heui-Soo; Baek, Ilseon; Chand, Vincent; Mather, Peter B
2016-05-07
The giant freshwater prawn, Macrobrachium rosenbergii, a sexually dimorphic decapod crustacean is currently the world's most economically important cultured freshwater crustacean species. Despite its economic importance, there is currently a lack of genomic resources available for this species, and this has limited exploration of the molecular mechanisms that control the M. rosenbergii sex-differentiation system more widely in freshwater prawns. Here, we present the first hybrid transcriptome from M. rosenbergii applying RNA-Seq technologies directed at identifying genes that have potential functional roles in reproductive-related traits. A total of 13,733,210 combined raw reads (1720 Mbp) were obtained from Ion-Torrent PGM and 454 FLX. Bioinformatic analyses based on three state-of-the-art assemblers, the CLC Genomic Workbench, Trans-ABySS, and Trinity, that use single and multiple k-mer methods respectively, were used to analyse the data. The influence of multiple k-mers on assembly performance was assessed to gain insight into transcriptome assembly from short reads. After optimisation, de novo assembly resulted in 44,407 contigs with a mean length of 437 bp, and the assembled transcripts were further functionally annotated to detect single nucleotide polymorphisms and simple sequence repeat motifs. Gene expression analysis was also used to compare expression patterns from ovary and testis tissue libraries to identify genes with potential roles in reproduction and sex differentiation. The large transcript set assembled here represents the most comprehensive set of transcriptomic resources ever developed for reproduction traits in M. rosenbergii, and the large number of genetic markers predicted should constitute an invaluable resource for future genetic research studies on M. rosenbergii and can be applied more widely on other freshwater prawn species in the genus Macrobrachium.
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Jung, Hyungtaek; Yoon, Byung-Ha; Kim, Woo-Jin; Kim, Dong-Wook; Hurwood, David A.; Lyons, Russell E.; Salin, Krishna R.; Kim, Heui-Soo; Baek, Ilseon; Chand, Vincent; Mather, Peter B.
2016-01-01
The giant freshwater prawn, Macrobrachium rosenbergii, a sexually dimorphic decapod crustacean is currently the world’s most economically important cultured freshwater crustacean species. Despite its economic importance, there is currently a lack of genomic resources available for this species, and this has limited exploration of the molecular mechanisms that control the M. rosenbergii sex-differentiation system more widely in freshwater prawns. Here, we present the first hybrid transcriptome from M. rosenbergii applying RNA-Seq technologies directed at identifying genes that have potential functional roles in reproductive-related traits. A total of 13,733,210 combined raw reads (1720 Mbp) were obtained from Ion-Torrent PGM and 454 FLX. Bioinformatic analyses based on three state-of-the-art assemblers, the CLC Genomic Workbench, Trans-ABySS, and Trinity, that use single and multiple k-mer methods respectively, were used to analyse the data. The influence of multiple k-mers on assembly performance was assessed to gain insight into transcriptome assembly from short reads. After optimisation, de novo assembly resulted in 44,407 contigs with a mean length of 437 bp, and the assembled transcripts were further functionally annotated to detect single nucleotide polymorphisms and simple sequence repeat motifs. Gene expression analysis was also used to compare expression patterns from ovary and testis tissue libraries to identify genes with potential roles in reproduction and sex differentiation. The large transcript set assembled here represents the most comprehensive set of transcriptomic resources ever developed for reproduction traits in M. rosenbergii, and the large number of genetic markers predicted should constitute an invaluable resource for future genetic research studies on M. rosenbergii and can be applied more widely on other freshwater prawn species in the genus Macrobrachium. PMID:27164098
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Hydrologic conditions in the South Coast aquifer, Puerto Rico, 2010–15
Torres-Gonzalez, Sigfredo; Rodriguez, Jose M.
2016-01-15
Water level declines reduce the thickness of freshwater in the unconfined parts of the South Coast aquifer. Additionally, the pumping-induced migration of poor-quality water from deep or seaward areas of the aquifer can contribute to reductions in the thickness of freshwater in the aquifer. The reduction in the freshwater saturated thickness of the aquifer in areas near Ponce, Juana Díaz, Salinas, and Guayama is of particular concern because the total saturated thickness of the aquifer is thinner in these areas. Total dissolved solids concentration in groundwater samples indicates a small positive trend in Ponce, Santa Isabel, Salinas, and Guayama. Diminished aquifer recharge during 2012 to 2015 and, to a lesser extent, increased groundwater withdrawals have resulted in a reduction in the freshwater saturated thickness of the aquifer. The reduction in freshwater saturated thickness of the aquifer may affect freshwater resources available for agriculture and public water supply. A prolonged time period with reduced aquifer recharge may have substantial implications for groundwater levels and fresh groundwater availability.
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Rivera-Monroy, V. H.; Twilley, R.R.; Davis, S.E.; Childers, D.L.; Simard, M.; Chambers, R.; Jaffe, R.; Boyer, J.N.; Rudnick, D.T.; Zhang, K.; Castaneda-Moya, E.; Ewe, S.M.L.; Price, R.M.; Coronado-Molina, C.; Ross, M.; Smith, T.J.; Michot, B.; Meselhe, E.; Nuttle, W.; Troxler, T.G.; Noe, G.B.
2011-01-01
The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional processes, mediated by water flow, control population and ecosystem dynamics across the EMER landscape. Tree canopies with maximum height <3 m cover 49% of the EMER, particularly in the SE region. These scrub/dwarf mangroves are the result of a combination of low soil phosphorus (P < 59 ??g P g dw-1) in the calcareous marl substrate and long hydroperiod. Phosphorus limits the EMER and its freshwater watersheds due to the lack of terrigenous sediment input and the phosphorus-limited nature of the freshwater Everglades. Reduced freshwater delivery over the past 50years, combined with Everglades compartmentalization and a 10 cm rise in coastal sea level, has led to the landward transgression (???1.5 km in 54 years) of the mangrove ecotone. Seasonal variation in freshwater input strongly controls the temporal variation of nitrogen and P exports (99%) from the Everglades to Florida Bay. Rapid changes in nutrient availability and vegetation distribution during the last 50years show that future ecosystem restoration actions and land use decisions can exert a major influence, similar to sea level rise over the short term, on nutrient cycling and wetland productivity in the EMER. Copyright ?? 2011 Taylor & Francis Group, LLC.
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Sustainable water future with global implications: everyone's responsibility.
Kuylenstierna, J L; Bjorklund, G; Najlis, P
1997-01-01
The current use and management of freshwater is not sustainable in many countries and regions of the world. If current trends are maintained, about two-thirds of the world's population will face moderate to severe water stress by 2025 compared to one-third at present. This water stress will hamper economic and social development unless action is taken to deal with the emerging problems. The Comprehensive Assessment of the Freshwater Resources of the World, prepared by the UN and the Stockholm Environment Institute, calls for immediate action to prevent further deterioration of freshwater resources. Although most problems related to water quantity and quality require national and regional solutions, only a global commitment can achieve the necessary agreement on principles, as well as financial means to attain sustainability. Due to the central and integrated role played by water in human activities, any measures taken need to incorporate a wide range of social, ecological and economic factors and needs. The Assessment thus addresses the many issues related to freshwater use, such as integrated land and water management at the watershed level, global food security, water supply and sanitation, ecosystem requirements, pollution, strengthening of major groups, and national water resource assessment capabilities and monitoring networks. Governments are urged to work towards a consensus regarding global principles and guidelines for integrated water management, and towards their implementation in local and regional water management situations. The alternative development options available to countries facing water stress, or the risk thereof, needs to be considered in all aspects of development planning.
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ASSESSMENT AND MANAGEMENT OF TOXICS IN THE WATERSHED
The demand for water is beginning to outstrip the available supply of water. The truly insidious insult to freshwater supplies comes from anthropogenic impacts that pollute freshwater supplies and the surrounding watersheds, making even less water available for use.
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Contribution of glacier runoff to freshwater discharge into the Gulf of Alaska
Neal, E.G.; Hood, E.; Smikrud, K.
2010-01-01
Watersheds along the Gulf of Alaska (GOA) are undergoing climate warming, glacier volume loss, and shifts in the timing and volume of freshwater delivered to the eastern North Pacific Ocean. We estimate recent mean annual freshwater discharge to the GOA at 870 km3 yr-1. Small distributed coastal drainages contribute 78% of the freshwater discharge with the remainder delivered by larger rivers penetrating coastal ranges. Discharge from glaciers and icefields accounts for 47% of total freshwater discharge, with 10% coming from glacier volume loss associated with rapid thinning and retreat of glaciers along the GOA. Our results indicate the region of the GOA from Prince William Sound to the east, where glacier runoff contributes 371 km3 yr -1, is vulnerable to future changes in freshwater discharge as a result of glacier thinning and recession. Changes in timing and magnitude of freshwater delivery to the GOA could impact coastal circulation as well as biogeochemical fluxes to near-shore marine ecosystems and the eastern North Pacific Ocean. Copyright ?? 2010 by the American Geophysical Union.
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Biomarkers of Type II Synthetic Pyrethroid Pesticides in Freshwater Fish
2014-01-01
Type II synthetic pyrethroids contain an alpha-cyano group which renders them more neurotoxic than their noncyano type I counterparts. A wide array of biomarkers have been employed to delineate the toxic responses of freshwater fish to various type II synthetic pyrethroids. These include hematological, enzymatic, cytological, genetic, omic and other types of biomarkers. This review puts together the applications of different biomarkers in freshwater fish species in response to the toxicity of the major type II pyrethroid pesticides and assesses their present status, while speculating on the possible future directions. PMID:24868555
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Biomarkers of type II synthetic pyrethroid pesticides in freshwater fish.
Kaviraj, Anilava; Gupta, Abhik
2014-01-01
Type II synthetic pyrethroids contain an alpha-cyano group which renders them more neurotoxic than their noncyano type I counterparts. A wide array of biomarkers have been employed to delineate the toxic responses of freshwater fish to various type II synthetic pyrethroids. These include hematological, enzymatic, cytological, genetic, omic and other types of biomarkers. This review puts together the applications of different biomarkers in freshwater fish species in response to the toxicity of the major type II pyrethroid pesticides and assesses their present status, while speculating on the possible future directions.
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TRANSLOCATION OF NUTRIENTS BY FRESHWATER MUSSELS – ALTERATION OF ECOSYSTEM AND COMMUNITY PROCESSES
Nutrient demand and availability is a major driver of ecosystem processes. We examined the impact of freshwater mussels, a highly imperiled faunal group, on nitrogen (N) and phosphorus (P) cycling and storage in three Oklahoma streams. We found that filter-feeding by freshwater m...
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Water security-National and global issues
Tindall, James A.; Campbell, Andrew A.
2010-01-01
Potable or clean freshwater availability is crucial to life and economic, environmental, and social systems. The amount of freshwater is finite and makes up approximately 2.5 percent of all water on the Earth. Freshwater supplies are small and randomly distributed, so water resources can become points of conflict. Freshwater availability depends upon precipitation patterns, changing climate, and whether the source of consumed water comes directly from desalination, precipitation, or surface and (or) groundwater. At local to national levels, difficulties in securing potable water sources increase with growing populations and economies. Available water improves living standards and drives urbanization, which increases average water consumption per capita. Commonly, disruptions in sustainable supplies and distribution of potable water and conflicts over water resources become major security issues for Government officials. Disruptions are often influenced by land use, human population, use patterns, technological advances, environmental impacts, management processes and decisions, transnational boundaries, and so forth.
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NASA Astrophysics Data System (ADS)
Shuster, W.
2016-12-01
The comparatively uncertain rainfall catch and rising seas in isolated North Pacific atoll communities has presented serious challenges to maintain human communities with freshwater volume. Moreover, the feudal hierarchy, which structures social and economic relationships among local governance and citizens contributes equally to problems and potential solutions. These relationships modulate the availability of critical ecosystem services generated by freshwater, with additional constraints contributed by climate change, rainfall variability (e.g., current El Niño climate pattern), and continuous threat of drought. The major freshwater resources for an atoll are the groundwater freshwater lens, residential and commercial rainwater harvesting, large-scale rainfall catchments (e.g., an airport runway), imported-virtual water, or desalinization subsidies. The significance of each of these resources scale across different atolls according to size, topography, soils, population, infrastructure, and land ownership. The potential integration and coordination of these water resources is largely unrealized due to land ownership, the lack of a contiguous catchment area, uneven and fractured governance. The situational aspects are further characterized by feuding among families and communities (some resource rich, some resource poor), and conflicting land use priorities where agriculture placement and practice can compromise the quality of already limited freshwater resources. This presentation uses the example of Majuro atoll (Republic of the Marshall Islands), field data and other observations, to illustrate sociohydrologic-drivers of freshwater availability, and suggests approaches that may improve on current and ongoing threats to public health and well-being.
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Extinction rates in North American freshwater fishes, 1900-2010
Burkhead, Noel M.
2012-01-01
Widespread evidence shows that the modern rates of extinction in many plants and animals exceed background rates in the fossil record. In the present article, I investigate this issue with regard to North American freshwater fishes. From 1898 to 2006, 57 taxa became extinct, and three distinct populations were extirpated from the continent. Since 1989, the numbers of extinct North American fishes have increased by 25%. From the end of the nineteenth century to the present, modern extinctions varied by decade but significantly increased after 1950 (post-1950s mean = 7.5 extinct taxa per decade). In the twentieth century, freshwater fishes had the highest extinction rate worldwide among vertebrates. The modern extinction rate for North American freshwater fishes is conservatively estimated to be 877 times greater than the background extinction rate for freshwater fishes (one extinction every 3 million years). Reasonable estimates project that future increases in extinctions will range from 53 to 86 species by 2050.
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The onshore influence of offshore fresh groundwater
NASA Astrophysics Data System (ADS)
Knight, Andrew C.; Werner, Adrian D.; Morgan, Leanne K.
2018-06-01
Freshwater contained within the submarine extensions of coastal aquifers is increasingly proposed as a freshwater source for coastal communities. However, the extent to which offshore freshwater supports onshore pumping is currently unknown on a global scale. This study provides the first attempt to examine the likely prevalence of situations where offshore freshwater influences onshore salinities, considering various sites from around the world. The groundwater conditions in twenty-seven confined and semi-confined coastal aquifers with plausible connections to inferred or observed offshore freshwater are explored. The investigation uses available onshore salinities and groundwater levels, and offshore salinity knowledge, in combination with analytical modelling, to develop simplified conceptual models of the study sites. Seven different conceptual models are proposed based on the freshwater-saltwater extent and insights gained from analytical modelling. We consider both present-day and pre-development conditions in assessing potential modern contributions to offshore fresh groundwater. Conceptual models also include interpretations of whether offshore freshwater is a significant factor influencing onshore salinities and well pumping sustainability. The results indicate that onshore water levels have declined between pre-development and present-day conditions in fourteen of the fifteen regions for which pre-development data are available. Estimates of the associated steady-state freshwater extents show the potential for considerable offshore fresh groundwater losses accompanying these declines. Both present-day and pre-development heads are insufficient to account for the observed offshore freshwater in all cases where adequate data exist. This suggests that paleo-freshwater and/or aquifer heterogeneities contribute significantly to offshore freshwater extent. Present-day heads indicate that active seawater intrusion (SWI) will eventually impact onshore pumping wells at fourteen of the twenty-seven sites, while passive SWI is expected onshore in an additional ten regions. Albeit the number of field sites is limited, there is sufficient evidence to indicate that when offshore freshwater has an onshore linkage, it is being mined either passively or actively by onshore use. Thus, offshore freshwater should be assessed in coastal water balances presuming that it serves as an existing freshwater input, rather than as a new potential freshwater resource.
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Bloom, Devin D; Weir, Jason T; Piller, Kyle R; Lovejoy, Nathan R
2013-07-01
Freshwater habitats make up only ∼0.01% of available aquatic habitat and yet harbor 40% of all fish species, whereas marine habitats comprise >99% of available aquatic habitat and have only 60% of fish species. One possible explanation for this pattern is that diversification rates are higher in freshwater habitats than in marine habitats. We investigated diversification in marine and freshwater lineages in the New World silverside fish clade Menidiinae (Teleostei, Atherinopsidae). Using a time-calibrated phylogeny and a state-dependent speciation-extinction framework, we determined the frequency and timing of habitat transitions in Menidiinae and tested for differences in diversification parameters between marine and freshwater lineages. We found that Menidiinae is an ancestrally marine lineage that independently colonized freshwater habitats four times followed by three reversals to the marine environment. Our state-dependent diversification analyses showed that freshwater lineages have higher speciation and extinction rates than marine lineages. Net diversification rates were higher (but not significant) in freshwater than marine environments. The marine lineage-through time (LTT) plot shows constant accumulation, suggesting that ecological limits to clade growth have not slowed diversification in marine lineages. Freshwater lineages exhibited an upturn near the recent in their LTT plot, which is consistent with our estimates of high background extinction rates. All sequence data are currently being archived on Genbank and phylogenetic trees archived on Treebase. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.
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NASA Astrophysics Data System (ADS)
Rotzoll, K.; Izuka, S. K.; Nishikawa, T.; Fienen, M. N.; El-Kadi, A. I.
2015-12-01
The volcanic-rock aquifers of Kauai, Oahu, and Maui are heavily developed, leading to concerns related to the effects of groundwater withdrawals on saltwater intrusion and streamflow. A numerical modeling analysis using the most recently available data (e.g., information on recharge, withdrawals, hydrogeologic framework, and conceptual models of groundwater flow) will substantially advance current understanding of groundwater flow and provide insight into the effects of human activity and climate change on Hawaii's water resources. Three island-wide groundwater-flow models were constructed using MODFLOW 2005 coupled with the Seawater-Intrusion Package (SWI2), which simulates the transition between saltwater and freshwater in the aquifer as a sharp interface. This approach allowed relatively fast model run times without ignoring the freshwater-saltwater system at the regional scale. Model construction (FloPy3), automated-parameter estimation (PEST), and analysis of results were streamlined using Python scripts. Model simulations included pre-development (1870) and current (average of 2001-10) scenarios for each island. Additionally, scenarios for future withdrawals and climate change were simulated for Oahu. We present our streamlined approach and preliminary results showing estimated effects of human activity on the groundwater resource by quantifying decline in water levels, reduction in stream base flow, and rise of the freshwater-saltwater interface.
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NASA Astrophysics Data System (ADS)
Ruhi, A.; Olden, J. D.; Sabo, J. L.
2015-12-01
In the American Southwest, hydrologic drought has become a new normal as a result of increasing human appropriation of freshwater resources and increased aridity associated with global warming. Although drought has often been touted to threaten freshwater biodiversity, connecting drought to extinction risk of highly-imperiled faunas remains a challenge. Here we combine time-series methods from signal processing and econometrics to analyze a spatially comprehensive and long-term dataset to link discharge variation and community abundance of fish across the American Southwest. This novel time series framework identifies ongoing trends in daily discharge anomalies across the Southwest, quantifies the effect of the historical hydrologic drivers on fish community abundance, and allows us to simulate species trajectories and range-wide risk of decline (quasiextinction) under scenarios of future climate. Spectral anomalies are declining over the last 30 years in at least a quarter of the stream gaging stations across the American Southwest and these anomalies are robust predictors of historical abundance of native and non-native fishes. Quasiextinction probabilities are high (>50 %) for nearly ¾ of the native species across several large river basins in the same region; and the negative trend in annual anomalies increases quasiextinction risk for native but reduces this risk for non-native fishes. These findings suggest that ongoing drought is causing range-wide collapse and replacement of native fish faunas, and that this homogenization of western fish faunas will continue given the prevailing negative trend in discharge anomalies. Additionally, this combination of methods can be applied elsewhere as long as environmental and biological long-term time-series data are available. Collectively, these methods allow identifying the link between hydroclimatic forcing and ecological responses and thus may help anticipating the potential impacts of ongoing and future hydrologic extremes in freshwater ecosystems.
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Risser, D.W.
1988-01-01
The quantity of freshwater available in the Post Headquarters well field, White Sand Missile Range, New Mexico, is limited and its quality is threatened by saltwater enroachment. A three-dimensional, finite-difference, groundwater flow model and a cross-sectional, density-dependent solute-transport model were constructed to simulate possible future water level declines and water quality changes in the Post Headquarters well field. A six-layer flow model was constructed using hydraulic-conductivity values in the upper 600 ft of saturated aquifer ranging from 0.1 to 10 ft/day, specific yield of 0.15, and average recharge of about 1,590 acre-ft/yr. Water levels simulated by the model closely matched measured water levels for 1948-82. Possible future water level changes for 1983-2017 were simulated using rates of groundwater withdrawal of 1,033 and 2 ,066 acre-ft/year and wastewater return flow of 0 or 30% of the groundwater withdrawal rate. The cross-sectional solute-transport model indicated that the freshwater zone is about 1,500 to 2,000 ft thick beneath the well field. Transient simulations show that solutes probably will move laterally toward the well field rather than from beneath the well field. (USGS)
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The Future of Water Security in Metropolitan Region of Sao Paulo Through Different Climate Scenarios
NASA Astrophysics Data System (ADS)
Gesualdo, G. C.; Oliveira, P. T. S.; Rodrigues, D. B. B.
2017-12-01
Achieving a balance between water availability and demand is one of the most pressing environmental challenges in the twenty-first century. This challenge is exacerbated by, climate change, which has already affected the water balance of landscapes globally by intensifying runoff, reducing snowpacks, and shifting precipitation regimes. Understanding these changes is crucial to identifying future water availability and developing sustainable management plans, especially in developing countries. Here, we address the developing country water balance challenge by assessing the influence of climate change on the water availability in the Jaguari basin, Southeastern Brazil. The Jaguari basin is one of the main sources of freshwater for 9 million people in the Metropolitan Region of São Paulo. This region represents about 7% of the Brazil's Gross Domestic Product. The critical importance of the water balance challenge in this area has been highlighted recently when a major drought in southeastern Brazil revealed the vulnerability of current water management systems. Still today, the per capita water availability in the region remains severely limited. To help address this water balance challenge, we use a modeling approach to predict future water vulnerabilities of this region under different climate scenarios. Here, we calibrated and validated a lumped conceptual model using HYMOD to evaluate future scenarios using downscaled climate models resulting from HadGEM2-ES and MIROC5 GCMs forced by RCP4.5 and RCP8.5 scenarios. We also present future directions which include bias correction from long-term weather station data and an empirical uncertainty assessment. Our results provide an important overview of climate change impacts on streamflow and future water availability in the Jaguari basin, which can be used to guide the basin`s water security plans and strategies.
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Hermoso, Virgilio; Januchowski-Hartley, Stephanie Renee; Linke, Simon; Dudgeon, David; Petry, Paulo; McIntyre, Peter
2017-09-01
The IUCN Red List is the most extensive source of conservation status assessments for species worldwide, but important gaps in coverage remain. Here, we demonstrate the use of a spatial prioritization approach to efficiently prioritize species assessments to achieve increased and up-to-date coverage efficiently. We focus on freshwater fishes, which constitute a significant portion of vertebrate diversity, although comprehensive assessments are available for only 46% of species. We used marxan to identify ecoregions for future assessments that maximize the coverage of species while accounting for anthropogenic stress. We identified a set of priority regions that would help assess one-third (ca 4000 species) of all freshwater fishes in need of assessment by 2020. Such assessments could be achieved without increasing current investment levels. Our approach is suitable for any taxon and can help ensure that species threat assessments are sufficiently complete to guide global conservation efforts in a rapidly changing world. © 2017 John Wiley & Sons Ltd.
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NASA Astrophysics Data System (ADS)
Houben, Georg; Noell, Ursula; Vassolo, Sara; Grissemann, Christoph; Geyh, Mebus; Stadler, Susanne; Dose, Eduardo J.; Vera, Sofia
2014-12-01
The occurrence of a freshwater lens in the Paraguayan Chaco, 900 km away from the ocean, is reported. It is located underneath sandstone hills, surrounded by lowlands with predominantly saline groundwater. Its geometry was delineated using geoelectrical and electromagnetic investigations. The unusual height of the fresh groundwater level can be attributed to the presence of a confining layer at depth. The lens receives its recharge exclusively from rainfall during the hot and humid summer months. It predominantly contains water predating the atmospheric atomic bomb tests, some of it probably up to a thousand or more years old. The water balance shows that extraction currently does not exceed recharge in normal years. However, the available volume of groundwater leaves little room for a further increase of extraction in the future. Recharge is augmented by return flow from thousands of latrines and cess pits, and this has lead to widespread contamination of the groundwater by faecal bacteria.
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Merritt, Michael L.
1997-01-01
This paper presents and interprets data from three cycles of injection, storage, and recovery of freshwater in a brackish aquifer through wells drilled at the Hialeah Water Treatment Plant in northeastern Dade County, Florida. Also described is an application of solute-transport modeling techniques to depict the hypothetical movement of the freshwater mass and to simulate the increasing salinity of the recovered water during the withdrawal phases. This paper also reports results of use of the calibrated model to predict recovery efficiencies in hypothetical future operational schedules of injection and recovery.
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NASA Astrophysics Data System (ADS)
Schmidt-Kloiber, Astrid; De Wever, Aaike; Bremerich, Vanessa; Strackbein, Jörg; Hering, Daniel; Jähnig, Sonja; Kiesel, Jens; Martens, Koen; Tockner, Klement
2017-04-01
Species distribution data is crucial for improving our understanding of biodiversity and its threats. This is especially the case for freshwater environments, which are heavily affected by the global biodiversity crisis. Currently, a huge body of freshwater biodiversity data is often difficult to access, because systematic data publishing practices have not yet been adopted by the freshwater research community. The Freshwater Information Platform (FIP; www.freshwaterplatform.eu) - initiated through the BioFresh project - aims at pooling freshwater related research information from a variety of projects and initiatives to make it easily accessible for scientists, water managers and conservationists as well as the interested public. It consists of several major components, three of which we want to specifically address: (1) The Freshwater Biodiversity Data Portal aims at mobilising freshwater biodiversity data, making them online available Datasets in the portal are described and documented in the (2) Freshwater Metadatabase and published as open access articles in the Freshwater Metadata Journal. The use of collected datasets for large-scale analyses and models is demonstrated in the (3) Global Freshwater Biodiversity Atlas that publishes interactive online maps featuring research results on freshwater biodiversity, resources, threats and conservation priorities. Here we present the main components of the FIP as tools to streamline open access freshwater data publication arguing this will improve the capacity to protect and manage freshwater biodiversity in the face of global change.
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Development of a coastal drought index using salinity data
Paul Conrads; Lisa Darby
2016-01-01
The location of the freshwater-saltwater interface in surface-water bodies is an important factor in the ecological and socio-economic dynamics of coastal communities. It influences community composition in freshwater and saltwater ecosystems, determines fisheries spawning habitat, and controls freshwater availability for municipal and industrial water intakes. These...
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Ronald S. Zalesny Jr.; John A. Stanturf; Steven R. Evett; Nabil F. Kandil; Christopher Soriano
2011-01-01
The Nile River provides nearly 97% of Egypt's freshwater supply. Egypt's share of Nile waters is fixed at 55.5 billion cubic meters annually. As a result, Egypt will not be able to meet increasing water demand using freshwater from the Nile and has been developing non-conventional wastewater reuse strategies to meet future demands. The USAID Mission in Cairo...
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Fitzpatrick, Faith A.; Boufadel, Michael C.; Johnson, Rex; Lee, Kenneth W.; Graan, Thomas P.; Bejarano, Adriana C.; Zhu, Zhenduo; Waterman, David; Capone, Daniel M.; Hayter, Earl; Hamilton, Stephen K.; Dekker, Timothy; Garcia, Marcelo H.; Hassan, Jacob S.
2015-01-01
Although much is known about oil-particle interactions in coastal marine environments, there remains a need for additional science on methods to detect and quantify the presence of OPAs and to understand their effects on containment and recovery of oil spilled under various temperature regimes and in different aquatic habitats including freshwater environments.
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Tracking animals in freshwater with electronic tags: past, present and future
Cooke, Steven J.; Midwood, Jonathan D.; Thiem, Jason D.; Klimley, Peter; Lucas, Martyn C.; Thorstad, Eva B.; Eiler, John; Holbrook, Chris; Ebner, Brendan C.
2013-01-01
Considerable technical developments over the past half century have enabled widespread application of electronic tags to the study of animals in the wild, including in freshwater environments. We review the constraints associated with freshwater telemetry and biologging and the technical developments relevant to their use. Technical constraints for tracking animals are often influenced by the characteristics of the animals being studied and the environment they inhabit. Collectively, they influence which and how technologies can be used and their relative effectiveness. Although radio telemetry has historically been the most commonly used technology in freshwater, passive integrated transponder (PIT) technology, acoustic telemetry and biologgers are becoming more popular. Most telemetry studies have focused on fish, although an increasing number have focused on other taxa, such as turtles, crustaceans and molluscs. Key technical developments for freshwater systems include: miniaturization of tags for tracking small-size life stages and species, fixed stations and coded tags for tracking large samples of animals over long distances and large temporal scales, inexpensive PIT systems that enable mass tagging to yield population- and community-level relevant sample sizes, incorporation of sensors into electronic tags, validation of tag attachment procedures with a focus on maintaining animal welfare, incorporation of different techniques (for example, genetics, stable isotopes) and peripheral technologies (for example, geographic information systems, hydroacoustics), development of novel analytical techniques, and extensive international collaboration. Innovations are still needed in tag miniaturization, data analysis and visualization, and in tracking animals over larger spatial scales (for example, pelagic areas of lakes) and in challenging environments (for example, large dynamic floodplain systems, under ice). There seems to be a particular need for adapting various global positioning system and satellite tagging approaches to freshwater. Electronic tagging provides a mechanism to collect detailed information from imperilled animals and species that have no direct economic value. Current and future advances will continue to improve our knowledge of the natural history of aquatic animals and ecological processes in freshwater ecosystems while facilitating evidence-based resource management and conservation.
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A subtropical fate awaited freshwater discharged from glacial Lake Agassiz
Condron, Alan; Winsor, Peter
2011-02-10
The 8.2 kyr event is the largest abrupt climatic change recorded in the last 10,000 years, and is widely hypothesized to have been triggered by the release of thousands of kilometers cubed of freshwater into the North Atlantic Ocean. Using a high-resolution (1/6°) global, ocean-ice circulation model we present an alternative view that freshwater discharged from glacial Lake Agassiz would have remained on the continental shelf as a narrow, buoyant, coastal current, and would have been transported south into the subtropical North Atlantic. The pathway we describe is in contrast to the conceptual idea that freshwater from this lake outburstmore » spread over most of the sub-polar North Atlantic, and covered the deep, open-ocean, convection regions. This coastally confined freshwater pathway is consistent with the present-day routing of freshwater from Hudson Bay, as well as paleoceanographic evidence of this event. In this study, using a coarse-resolution (2.6°) version of the same model, we demonstrate that the previously reported spreading of freshwater across the sub-polar North Atlantic results from the inability of numerical models of this resolution to accurately resolve narrow coastal flows, producing instead a diffuse circulation that advects freshwater away from the boundaries. To understand the climatic impact of freshwater released in the past or future (e.g. Greenland and Antarctica), the ocean needs to be modeled at a resolution sufficient to resolve the dynamics of narrow, coastal buoyant flows.« less
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Seasonal comparison of aquatic macroinvertebrate assemblages in a flooded coastal freshwater marsh
Kang, Sung-Ryong; King, Sammy L.
2013-01-01
Marsh flooding and drying may be important factors affecting aquatic macroinvertebrate density and distribution in coastal freshwater marshes. Limited availability of water as a result of drying in emergent marsh may decrease density, taxonomic diversity, and taxa richness. The principal objectives of this study are to characterize the seasonal aquatic macroinvertebrate assemblage in a freshwater emergent marsh and compare aquatic macroinvertebrate species composition, density, and taxonomic diversity to that of freshwater marsh ponds. We hypothesize that 1) freshwater emergent marsh has lower seasonal density and taxonomic diversity compared to that of freshwater marsh ponds; and 2) freshwater emergent marsh has lower taxa richness than freshwater marsh ponds. Seasonal aquatic macroinvertebrate density in freshwater emergent marsh ranged from 0 organisms/m2 (summer 2009) to 91.1 ± 20.53 organisms/m2 (mean ± SE; spring 2009). Density in spring was higher than in all other seasons. Taxonomic diversity did not differ and there were no unique species in the freshwater emergent marsh. Our data only partially support our first hypothesis as aquatic macroinvertebrate density and taxonomic diversity between freshwater emergent marsh and ponds did not differ in spring, fall, and winter but ponds supported higher macroinvertebrate densities than freshwater emergent marsh during summer. However, our data did not support our second hypothesis as taxa richness between freshwater emergent marsh and ponds did not statistically differ.
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Genetic studies of freshwater turtle and tortoises: a review of the past 70 years
FitzSimmons, Nancy N.; Hart, Kristen M.
2007-01-01
Powerful molecular techniques have been developed over many decades for resolving genetic relationships, population genetic structure, patterns of gene flow, mating systems, and the amount of genetic diversity in animals. Genetic studies of turtles were among the earliest and the rapid application of new genetic tools and analytical techniques is still apparent in the literature on turtles. At present, of the 198 freshwater turtles and tortoises that are listed as not extinct by the IUCN Red List, 69 species worldwide are listed as endangered or critically endangered, and an additional 56 species are listed as vulnerable. Of the ca. 300 species of the freshwater turtles and tortoises in the world, ca. 42% are considered to be facing a high risk extinction, and there is a need to focus intense conservation attention on these species. This includes a need to (i) assess our current state of knowledge regarding the application of genetics to studies of freshwater turtles and tortoises and (ii) determine future research directions. Here, we review all available published studies for the past 70 years that were written in English and used genetic markers (e.g. karyotypes, allozymes, DNA loci) to better understand the biology of freshwater turtles and tortoises. We review the types of studies conducted in relation to the species studied and quantify the countries where the studies were performed. We rack the changing use of different genetic markers through time and report on studies focused on aspects of molecular evolution within turtle genomes. We address the usefulness of particular genetic markers to answer phylogenetic questions and present data comparing population genetic structure and mating systems across species. We draw specific attention to whether authors have considered issues to turtle conservation in their research or provided new insights that have been translated into recommendations for conservation management.
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Ng, Ting Hui; Dulipat, Jasrul; Foon, Junn Kitt; Lopes-Lima, Manuel; Alexandra Zieritz; Liew, Thor-Seng
2017-01-01
Abstract Sabah, a Malaysian state at the north-eastern tip of Borneo, is situated in one of the Earth’s biodiversity hotspots yet its freshwater gastropod diversity remains poorly known. An annotated checklist of the freshwater gastropods is presented, based on specimens deposited in the BORNEENSIS collection of the Institute for Tropical Biology and Conservation at Universiti Malaysia Sabah, Malaysia. A KMZ file is also provided, which acts as a repository of digital images and complete collection data of all examined material, so that it can be shared and adapted to facilitate future research. PMID:28769673
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Transitioning to Zero Freshwater Withdrawal for Thermoelectric Generation
NASA Astrophysics Data System (ADS)
Macknick, J.; Tidwell, V. C.; Zemlick, K. M.; Sanchez, J.; Woldeyesus, T.
2013-12-01
The electricity sector is the largest withdrawer of freshwater in the United States. The primary demand for water from the electricity sector is for cooling thermoelectric power plants. Droughts and potential changes in water resources resulting from climate change pose important risks to thermoelectric power production in the United States. Power plants can minimize risk in a variety of ways. One method of reducing risk is to move away from dependency on freshwater resources. Here a scoping level analysis is performed to identify the technical tradeoffs and initial cost estimates for retrofitting all existing steam-powered generation to achieve zero freshwater withdrawal. Specifically, the conversion of existing freshwater-cooled plants to dry cooling or a wet cooling system utilizing non-potable water is considered. The least cost alternative is determined for each of the 1,178 freshwater using power plants in the United States. The use of non-potable water resources, such as municipal wastewater and shallow brackish groundwater, is considered based on the availability and proximity of those resources to the power plant, as well as the costs to transport and treat those resources to an acceptable level. The projected increase in levelized cost of electricity due to power plant retrofits ranges roughly from 0.20 to 20/MWh with a median value of 3.53/MWh. With a wholesale price of electricity running about 35/MWh, many retrofits could be accomplished at levels that would add less than 10% to current power plant generation expenses. Such retrofits could alleviate power plant vulnerabilities to thermal discharge limits in times of drought (particularly in the East) and would save 3.2 Mm3/d of freshwater consumption in watersheds with limited water availability (principally in the West). The estimated impact of retrofits on wastewater and brackish water supply is minimal requiring only a fraction of the available resource. Total parasitic energy requirements to achieve zero freshwater withdrawal are estimated at 140 million MWh or roughly 4.5% of the initial production from the retrofitted plants.
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Wesley, Neal J.; Lilyestrom, Craig G.; Kwak, T.J.
2009-01-01
Anthropogenic effects including river regulation, watershed development, contamination, and fish introductions have substantially affected the majority of freshwater habitats in Europe and North America. This pattern of resource development and degradation is widespread in the tropics, and often little is known about the resources before they are lost. This article describes the freshwater resources of Puerto Rico and identifies factors that threaten conservation of native fishes. The fishes found in freshwater habitats of Puerto Rico represent a moderately diverse assemblage composed of 14 orders, 29 families, and 82 species. There are fewer than 10 species of native peripherally-freshwater fish that require a link to marine systems. Introductions of nonindigenous species have greatly expanded fish diversity in freshwater systems, and native estuarine and marine species (18 families) also commonly enter lowland rivers and brackish lagoons. Environmental alterations, including land use and development, stream channelization, pollution, and the impoundment of rivers, combined with nonnative species introductions threaten the health and sustainability of aquatic resources in Puerto Rico. Six principal areas for attention that are important influences on the current and future status of the freshwater fish resources of Puerto Rico are identified and discussed.
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Meeting ecological and societal needs for freshwater
Baron, Jill S.; Poff, N.L.; Angermeier, P.L.; Dahm, Clifford N.; Gleick, P.H.; Hairston, N.G.; Jackson, R.B.; Johnston, C.A.; Richter, B.D.; Steinman, A.D.
2002-01-01
Human society has used freshwater from rivers, lakes, groundwater, and wetlands for many different urban, agricultural, and industrial activities, but in doing so has overlooked its value in supporting ecosystems. Freshwater is vital to human life and societal well-being, and thus its utilization for consumption, irrigation, and transport has long taken precedence over other commodities and services provided by freshwater ecosystems. However, there is growing recognition that functionally intact and biologically complex aquatic ecosystems provide many economically valuable services and long-term benefits to society. The short-term benefits include ecosystem goods and services, such as food supply, flood control, purification of human and industrial wastes, and habitat for plant and animal life—and these are costly, if not impossible, to replace. Long-term benefits include the sustained provision of those goods and services, as well as the adaptive capacity of aquatic ecosystems to respond to future environmental alterations, such as climate change. Thus, maintenance of the processes and properties that support freshwater ecosystem integrity should be included in debates over sustainable water resource allocation.The purpose of this report is to explain how the integrity of freshwater ecosystems depends upon adequate quantity, quality, timing, and temporal variability of water flow. Defining these requirements in a comprehensive but general manner provides a better foundation for their inclusion in current and future debates about allocation of water resources. In this way the needs of freshwater ecosystems can be legitimately recognized and addressed. We also recommend ways in which freshwater ecosystems can be protected, maintained, and restored.Freshwater ecosystem structure and function are tightly linked to the watershed or catchment of which they are a part. Because riverine networks, lakes, wetlands, and their connecting groundwaters, are literally the “sinks” into which landscapes drain, they are greatly influenced by terrestrial processes, including many human uses or modifications of land and water. Freshwater ecosystems, whether lakes, wetlands, or rivers, have specific requirements in terms of quantity, quality, and seasonality of their water supplies. Sustainability normally requires these systems to fluctuate within a natural range of variation. Flow regime, sediment and organic matter inputs, thermal and light characteristics, chemical and nutrient characteristics, and biotic assemblages are fundamental defining attributes of freshwater ecosystems. These attributes impart relatively unique characteristics of productivity and biodiversity to each ecosystem. The natural range of variation in each of these attributes is critical to maintaining the integrity and dynamic potential of aquatic ecosystems; therefore, management should allow for dynamic change. Piecemeal approaches cannot solve the problems confronting freshwater ecosystems.Scientific definitions of the requirements to protect and maintain aquatic ecosystems are necessary but insufficient for establishing the appropriate distribution between societal and ecosystem water needs. For scientific knowledge to be implemented science must be connected to a political agenda for sustainable development. We offer these recommendations as a beginning to redress how water is viewed and managed in the United States: (1) Frame national and regional water management policies to explicitly incorporate freshwater ecosystem needs, particularly those related to naturally variable flow regimes and to the linking of water quality with water quantity; (2) Define water resources to include watersheds, so that freshwaters are viewed within a landscape, or systems context; (3) Increase communication and education across disciplines, especially among engineers, hydrologists, economists, and ecologists to facilitate an integrated view of freshwater resources; (4) Increase restoration efforts, using well-grounded ecological principles as guidelines; (5) Maintain and protect the remaining freshwater ecosystems that have high integrity; and (6) Recognize the dependence of human society on naturally functioning ecosystems.
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Opportunities for woody crop production using treated wastewater in Egypt
R.S. Zalesny; S.R. Evett; N.F. Kandil; C. Soriano; John Stanturf
2011-01-01
The Nile River provides nearly 97% of Egyptâs freshwater supply. Egyptâs share of Nile waters is fixed at 55.5 billion cubic meters annually. As a result, Egypt will not be able to meet increasing water demand using freshwater from the Nile and has been developing non-conventional wastewater reuse strategies to meet future demands. The USAID Mission in Cairo began...
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Horton, Alice A; Walton, Alexander; Spurgeon, David J; Lahive, Elma; Svendsen, Claus
2017-05-15
Plastic debris is an environmentally persistent and complex contaminant of increasing concern. Understanding the sources, abundance and composition of microplastics present in the environment is a huge challenge due to the fact that hundreds of millions of tonnes of plastic material is manufactured for societal use annually, some of which is released to the environment. The majority of microplastics research to date has focussed on the marine environment. Although freshwater and terrestrial environments are recognised as origins and transport pathways of plastics to the oceans, there is still a comparative lack of knowledge about these environmental compartments. It is highly likely that microplastics will accumulate within continental environments, especially in areas of high anthropogenic influence such as agricultural or urban areas. This review critically evaluates the current literature on the presence, behaviour and fate of microplastics in freshwater and terrestrial environments and, where appropriate, also draws on relevant studies from other fields including nanotechnology, agriculture and waste management. Furthermore, we evaluate the relevant biological and chemical information from the substantial body of marine microplastic literature, determining the applicability and comparability of this data to freshwater and terrestrial systems. With the evidence presented, the authors have set out the current state of the knowledge, and identified the key gaps. These include the volume and composition of microplastics entering the environment, behaviour and fate of microplastics under a variety of environmental conditions and how characteristics of microplastics influence their toxicity. Given the technical challenges surrounding microplastics research, it is especially important that future studies develop standardised techniques to allow for comparability of data. The identification of these research needs will help inform the design of future studies, to determine both the extent and potential ecological impacts of microplastic pollution in freshwater and terrestrial environments. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Venteris, Erik R.; Skaggs, Richard; Coleman, Andre M.
2013-03-15
A key advantage of using microalgae for biofuel production is the ability of some algal strains to thrive in waters unsuitable for conventional crop irrigation such as saline groundwater or seawater. Nonetheless, the availability of sustainable water supplies will provide significant challenges for scale-up and development of algal biofuels. We conduct a limited techno-economic assessment based on the availability of freshwater, saline groundwater, and seawater for use in open pond algae cultivation systems. We explore water issues through GIS-based models of algae biofuel production, freshwater supply, and cost models for supplying seawater and saline groundwater. We estimate that combined, withinmore » the coterminous US these resources can support production on the order of 9.46E+7 m3 yr-1 (25 billion gallons yr-1) of renewable biodiesel. Achievement of larger targets requires the utilization of less water efficient sites and relatively expensive saline waters. Geographically, water availability is most favorable for the coast of the Gulf of Mexico and Florida peninsula, where evaporation relative to precipitation is moderate and various saline waters are economically available. As a whole, barren and scrub lands of the southwestern US have limited freshwater supplies so accurate assessment of alternative waters is critical.« less
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NASA Astrophysics Data System (ADS)
Segarra, Katherine E. A.; Comerford, Christopher; Slaughter, Julia; Joye, Samantha B.
2013-08-01
Methane, a powerful greenhouse gas, is both produced and consumed in anoxic coastal sediments via microbial processes. Although the anaerobic oxidation of methane (AOM) is almost certainly an important process in coastal freshwater and salt marsh sediments, the factors that control the rates and pathways of AOM in these habitats are poorly understood. Here, we present the first direct measurements of AOM activity in freshwater (0 PSU) and brackish (25 PSU) wetland sediments. Despite disparate sulfate concentrations, both environments supported substantial rates of AOM. Higher sulfate reduction (SR) rates were measured in the freshwater site and SR at both sites was of sufficient magnitude to support the observed AOM activity. Laboratory incubations of freshwater and brackish tidal, wetland sediments amended with either nothing [control], sulfate, nitrate, manganese oxide (birnessite) or iron oxide (ferrihydrite) and supplied with a methane headspace were used to evaluate the impact(s) of electron acceptor availability on potential AOM rates. Maximum AOM rates in brackish slurries occurred in the sulfate amendments. In contrast, addition of sulfate and several possible electron acceptors to the freshwater slurries decreased AOM rates relative to the control. High ratios of AOM activity relative to SR activity in the nitrate, birnessite, and ferrihydrite treatments of both the brackish and freshwater slurries provided evidence of AOM decoupled from SR. This study demonstrates that both freshwater and brackish coastal wetland sediments support considerable rates of anaerobic methanotrophy and provides evidence for sulfate-independent AOM that may be coupled to nitrate, iron, or manganese reduction in both environments.
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NASA Astrophysics Data System (ADS)
Gephart, Jessica A.; Troell, Max; Henriksson, Patrik J. G.; Beveridge, Malcolm C. M.; Verdegem, Marc; Metian, Marc; Mateos, Lara D.; Deutsch, Lisa
2017-12-01
Freshwater use for food production is projected to increase substantially in the coming decades with population growth, changing demographics, and shifting diets. Ensuring joint food-water security has prompted efforts to quantify freshwater use for different food products and production methods. However, few analyses quantify freshwater use for seafood production, and those that do use inconsistent water accounting. This inhibits water use comparisons among seafood products or between seafood and agricultural/livestock products. This 'seafood gap' in the food-water nexus literature will become increasingly problematic as seafood consumption is growing globally and aquaculture is one of the fastest growing animal food sectors in the world. Therefore, the present study 1) reviews freshwater use concepts as they relate to seafood production; 2) provides three cases to highlight the particular water use concerns for aquaculture, and; 3) outlines future directions to integrate seafood into the broader food-water nexus discussion. By revisiting water use concepts through a focus on seafood production systems, we highlight the key water use processes that should be considered for seafood production and offer a fresh perspective on the analysis of freshwater use in food systems more broadly.
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NASA Astrophysics Data System (ADS)
Rawlins, M. A.; Adam, J. C.; Vorosmarty, C. J.; Serreze, M. C.; Hinzman, L. D.; Holland, M.; Shiklomanov, A.
2007-12-01
It is expected that a warming climate will be attended by an intensification of the global hydrological cycle. While there are signs of positive trends in several hydrological quantities emerging at the global scale, the scope, character, and quantitative significance of these changes are not well established. In particular, long-term increases in river discharge across Arctic Eurasia are assumed to represent such an intensification and have received considerable attention. Yet, no change in long-term annual precipitation across the region can be related with the discharge trend. Given linkages and feedbacks between the arctic and global climate systems, a more complete understanding of observed changes across northern high latitudes is needed. We present a working definition of an accelerated or intensified hydrological cycle and a synthesis of long-term (nominally 50 years) trends in observed freshwater stocks and fluxes across the arctic land-atmosphere-ocean system. Trend and significance measures from observed data are described alongside expectations of intensification based on GCM simulations of contemporary and future climate. Our domain of interest includes the terrestrial arctic drainage (including all of Alaska and drainage to Hudson Bay), the Arctic Ocean, and the atmosphere over the land and ocean domains. For the terrestrial Arctic, time series of spatial averages which are derived from station data and atmospheric reanalysis are available. Reconstructed data sets are used for quantities such as Arctic Ocean ice and liquid freshwater transports. Study goals include a comprehensive survey of past changes in freshwater across the pan-arctic and a set of benchmarks for expected changes based on an ensemble of GCM simulations, and identification of potential mechanistic linkages which may be examined with contemporary remote sensing data sets.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Ping; Omani, Nina; Chaubey, Indrajeet
Drought is one of the most widespread extreme climate events with a potential to alter freshwater availability and related ecosystem services. Given the interconnectedness between freshwater availability and many ecosystem services, including food provisioning, it is important to evaluate the drought implications on freshwater provisioning and food provisioning services. Studies about drought implications on streamflow, nutrient loads, and crop yields have been increased and these variables are all process-based model outputs that could represent ecosystem functions that contribute to the ecosystem services. However, few studies evaluate drought effects on ecosystem services such as freshwater and food provisioning and quantify thesemore » services using an index-based ecosystem service approach. In this study, the drought implications on freshwater and food provisioning services were evaluated for 14 four-digit HUC (Hydrological Unit Codes) subbasins in the Upper Mississippi River Basin (UMRB), using three drought indices: standardized precipitation index (SPI), standardized soil water content index (SSWI), and standardized streamflow index (SSI). The results showed that the seasonal freshwater provisioning was highly affected by the precipitation deficits and/or surpluses in summer and autumn. A greater importance of hydrological drought than meteorological drought implications on freshwater provisioning was evident for the majority of the subbasins, as evidenced by higher correlations between freshwater provisioning and SSI12 than SPI12. Food provisioning was substantially affected by the precipitation and soil water deficits during summer and early autumn, with relatively less effect observed in winter. A greater importance of agricultural drought effects on food provisioning was evident for most of the subbasins during crop reproductive stages. Results from this study may provide insights to help make effective land management decisions in responding to extreme climate conditions in order to protect and restore freshwater provisioning and food provisioning services in the UMRB.« less
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Li, Ping; Omani, Nina; Chaubey, Indrajeet; Wei, Xiaomei
2017-05-08
Drought is one of the most widespread extreme climate events with a potential to alter freshwater availability and related ecosystem services. Given the interconnectedness between freshwater availability and many ecosystem services, including food provisioning, it is important to evaluate the drought implications on freshwater provisioning and food provisioning services. Studies about drought implications on streamflow, nutrient loads, and crop yields have been increased and these variables are all process-based model outputs that could represent ecosystem functions that contribute to the ecosystem services. However, few studies evaluate drought effects on ecosystem services such as freshwater and food provisioning and quantify these services using an index-based ecosystem service approach. In this study, the drought implications on freshwater and food provisioning services were evaluated for 14 four-digit HUC (Hydrological Unit Codes) subbasins in the Upper Mississippi River Basin (UMRB), using three drought indices: standardized precipitation index ( SPI ), standardized soil water content index ( SSWI ), and standardized streamflow index ( SSI ). The results showed that the seasonal freshwater provisioning was highly affected by the precipitation deficits and/or surpluses in summer and autumn. A greater importance of hydrological drought than meteorological drought implications on freshwater provisioning was evident for the majority of the subbasins, as evidenced by higher correlations between freshwater provisioning and SSI 12 than SPI 12. Food provisioning was substantially affected by the precipitation and soil water deficits during summer and early autumn, with relatively less effect observed in winter. A greater importance of agricultural drought effects on food provisioning was evident for most of the subbasins during crop reproductive stages. Results from this study may provide insights to help make effective land management decisions in responding to extreme climate conditions in order to protect and restore freshwater provisioning and food provisioning services in the UMRB.
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Li, Ping; Omani, Nina; Chaubey, Indrajeet; Wei, Xiaomei
2017-01-01
Drought is one of the most widespread extreme climate events with a potential to alter freshwater availability and related ecosystem services. Given the interconnectedness between freshwater availability and many ecosystem services, including food provisioning, it is important to evaluate the drought implications on freshwater provisioning and food provisioning services. Studies about drought implications on streamflow, nutrient loads, and crop yields have been increased and these variables are all process-based model outputs that could represent ecosystem functions that contribute to the ecosystem services. However, few studies evaluate drought effects on ecosystem services such as freshwater and food provisioning and quantify these services using an index-based ecosystem service approach. In this study, the drought implications on freshwater and food provisioning services were evaluated for 14 four-digit HUC (Hydrological Unit Codes) subbasins in the Upper Mississippi River Basin (UMRB), using three drought indices: standardized precipitation index (SPI), standardized soil water content index (SSWI), and standardized streamflow index (SSI). The results showed that the seasonal freshwater provisioning was highly affected by the precipitation deficits and/or surpluses in summer and autumn. A greater importance of hydrological drought than meteorological drought implications on freshwater provisioning was evident for the majority of the subbasins, as evidenced by higher correlations between freshwater provisioning and SSI12 than SPI12. Food provisioning was substantially affected by the precipitation and soil water deficits during summer and early autumn, with relatively less effect observed in winter. A greater importance of agricultural drought effects on food provisioning was evident for most of the subbasins during crop reproductive stages. Results from this study may provide insights to help make effective land management decisions in responding to extreme climate conditions in order to protect and restore freshwater provisioning and food provisioning services in the UMRB. PMID:28481311
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Li, Ping; Omani, Nina; Chaubey, Indrajeet; ...
2017-05-08
Drought is one of the most widespread extreme climate events with a potential to alter freshwater availability and related ecosystem services. Given the interconnectedness between freshwater availability and many ecosystem services, including food provisioning, it is important to evaluate the drought implications on freshwater provisioning and food provisioning services. Studies about drought implications on streamflow, nutrient loads, and crop yields have been increased and these variables are all process-based model outputs that could represent ecosystem functions that contribute to the ecosystem services. However, few studies evaluate drought effects on ecosystem services such as freshwater and food provisioning and quantify thesemore » services using an index-based ecosystem service approach. In this study, the drought implications on freshwater and food provisioning services were evaluated for 14 four-digit HUC (Hydrological Unit Codes) subbasins in the Upper Mississippi River Basin (UMRB), using three drought indices: standardized precipitation index (SPI), standardized soil water content index (SSWI), and standardized streamflow index (SSI). The results showed that the seasonal freshwater provisioning was highly affected by the precipitation deficits and/or surpluses in summer and autumn. A greater importance of hydrological drought than meteorological drought implications on freshwater provisioning was evident for the majority of the subbasins, as evidenced by higher correlations between freshwater provisioning and SSI12 than SPI12. Food provisioning was substantially affected by the precipitation and soil water deficits during summer and early autumn, with relatively less effect observed in winter. A greater importance of agricultural drought effects on food provisioning was evident for most of the subbasins during crop reproductive stages. Results from this study may provide insights to help make effective land management decisions in responding to extreme climate conditions in order to protect and restore freshwater provisioning and food provisioning services in the UMRB.« less
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Ecophysiology of Freshwater Verrucomicrobia Inferred from Metagenome-Assembled Genomes
He, Shaomei; Stevens, Sarah L. R.; Chan, Leong-Keat; Bertilsson, Stefan; Glavina del Rio, Tijana; Tringe, Susannah G.; Malmstrom, Rex R.
2017-01-01
ABSTRACT Microbes are critical in carbon and nutrient cycling in freshwater ecosystems. Members of the Verrucomicrobia are ubiquitous in such systems, and yet their roles and ecophysiology are not well understood. In this study, we recovered 19 Verrucomicrobia draft genomes by sequencing 184 time-series metagenomes from a eutrophic lake and a humic bog that differ in carbon source and nutrient availabilities. These genomes span four of the seven previously defined Verrucomicrobia subdivisions and greatly expand knowledge of the genomic diversity of freshwater Verrucomicrobia. Genome analysis revealed their potential role as (poly)saccharide degraders in freshwater, uncovered interesting genomic features for this lifestyle, and suggested their adaptation to nutrient availabilities in their environments. Verrucomicrobia populations differ significantly between the two lakes in glycoside hydrolase gene abundance and functional profiles, reflecting the autochthonous and terrestrially derived allochthonous carbon sources of the two ecosystems, respectively. Interestingly, a number of genomes recovered from the bog contained gene clusters that potentially encode a novel porin-multiheme cytochrome c complex and might be involved in extracellular electron transfer in the anoxic humus-rich environment. Notably, most epilimnion genomes have large numbers of so-called “Planctomycete-specific” cytochrome c-encoding genes, which exhibited distribution patterns nearly opposite to those seen with glycoside hydrolase genes, probably associated with the different levels of environmental oxygen availability and carbohydrate complexity between lakes/layers. Overall, the recovered genomes represent a major step toward understanding the role, ecophysiology, and distribution of Verrucomicrobia in freshwater. IMPORTANCE Freshwater Verrucomicrobia spp. are cosmopolitan in lakes and rivers, and yet their roles and ecophysiology are not well understood, as cultured freshwater Verrucomicrobia spp. are restricted to one subdivision of this phylum. Here, we greatly expanded the known genomic diversity of this freshwater lineage by recovering 19 Verrucomicrobia draft genomes from 184 metagenomes collected from a eutrophic lake and a humic bog across multiple years. Most of these genomes represent the first freshwater representatives of several Verrucomicrobia subdivisions. Genomic analysis revealed Verrucomicrobia to be potential (poly)saccharide degraders and suggested their adaptation to carbon sources of different origins in the two contrasting ecosystems. We identified putative extracellular electron transfer genes and so-called “Planctomycete-specific” cytochrome c-encoding genes and identified their distinct distribution patterns between the lakes/layers. Overall, our analysis greatly advances the understanding of the function, ecophysiology, and distribution of freshwater Verrucomicrobia, while highlighting their potential role in freshwater carbon cycling. PMID:28959738
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Housen Chu; Johan F. Gottgens; Jiquan Chen; Ge Sun; Ankur R. Desai; Zutao Ouyang; Changliang Shao; Kevin Czajkowski
2015-01-01
Freshwater marshes are well-known for their ecological functions in carbon sequestration, but complete carbon budgets that include both methane (CH4) and lateral carbon fluxes for these ecosystems are rarely available. To the best of our knowledge, this is the first full carbon balance for a freshwater marsh where vertical gaseous [carbon dioxide (CO2) and CH4] and...
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Gingerich, Stephen B.
2013-01-01
Owing to population growth, freshwater demand on Guam has increased in the past and will likely increase in the future. During the early 1970s to 2010, groundwater withdrawals from the limestone Northern Guam Lens Aquifer, the main source of freshwater on the island, tripled from about 15 to 45 million gallons per day. Because of proposed military relocation to Guam and expected population growth, freshwater demand on Guam is projected to increase further. The expected increased demand for groundwater has led to concern over the long-term sustainability of withdrawals from existing and proposed wells. A three-dimensional numerical groundwater flow and transport model was developed to simulate the effects of hypothetical withdrawal and recharge scenarios on water levels and on the transition zone between freshwater and saltwater. The model was constructed by using average recharge during 1961–2005 and withdrawals from 2010. Hydraulic properties used to construct the model were initially based on published estimates but ultimately were adjusted to obtain better agreement between simulated and measured water levels and salinity profiles in the modeled area. Two hypothetical groundwater withdrawal scenarios were simulated: no withdrawal to simulate predevelopment conditions and withdrawal at 2010 rates under a 5-year drought. Simulation results indicate that prior to pumping; the fresh-water lens was 10 to 50 feet thicker in the Yigo-Tumon basin and more than 50 feet thicker in the Hagåtña basin. Results also indicate that continuing the 2010 withdrawal distribution during a 5-year drought would result in decreased water levels, a thinner freshwater lens, and increased salinity of water pumped from wells. The available water with an acceptable salinity (chloride concentration less than 200 milligrams per liter) would decrease from about 34 million gallons per day to 11.5 million gallons per day after 5 years but recover to pre-drought levels 5 years after the return of average recharge conditions. Five additional scenarios were simulated to assess groundwater demand projections and proposed new well sites for the Department of Defense and Guam Water Authority wells under average and drought conditions. Simulation results from these projected withdrawal scenarios indicate decreased water levels, a thinner freshwater lens, increased water salinity, and unacceptable salinity at several current withdrawal sites. However, for the scenario including projected U.S. Marine Corps demands (46.62 million gallons per day, including 10 proposed wells) more than 40 million gallons per day of the withdrawn groundwater remains in the acceptable category. During a 5-year drought, this same pumping distribution results in only about 15 million gallons per day of withdrawn groundwater having acceptable salinity. A scenario in which groundwater withdrawal was redistributed in an attempt to maximize withdrawal while maintaining acceptable salinities in the withdrawn water was simulated. The redistributed withdrawal simulates about 47 million gallons per day of withdrawal with more than 41 million gallons per day of withdrawal with acceptable salinity.
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Extinction rates in North American freshwater fishes, 1900-2010
Burkhead, Noel M.
2012-01-01
Widespread evidence shows that the modern rates of extinction in many plants and animals exceed background rates in the fossil record. In the present article, I investigate this issue with regard to North American freshwater fishes. From 1898 to 2006, 57 taxa became extinct, and three distinct populations were extirpated from the continent. Since 1989, the numbers of extinct North American fishes have increased by 25%. From the end of the nineteenth century to the present, modern extinctions varied by decade but significantly increased after 1950 (post-1950s mean = 7.5 extinct taxa per decade). The modern extinction rate for North American freshwater fishes is conservatively estimated to be 877 times greater than the background extinction rate for freshwater fishes (one extinction every 3 million years). Reasonable estimates project that future increases in extinctions will range from 53 to 86 species by 2050.
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Effects of salinity on freshwater fishes in coastal plain drainages in the southeastern U.S.
Peterson, Mark S.; Meador, Michael R.
1994-01-01
This review focuses on the influence of salinity on freshwater fishes in coastal rivers and estuaries of the southeastern U.S. Influences of salinity on freshwater fish species can be explained partly through responses evidenced by behavior, physiology, growth, reproduction, and food habits during all aspects of life history. Factors influencing the rate of salinity change affect the community structure and dynamics of freshwater fishes in brackish environments. Our understanding of the relation between salinity and the life history of freshwater fishes is limited because little ecological research has been conducted in low-salinity habitats that we consider an “interface” between freshwater streams and the estuary proper. Much of the available data are descriptive in nature and describe best general patterns, but more specific studies are required to better determine the influence of salinity on freshwater fishes. Improved understanding of the influence of human-induced changes on the productivity and viability of these important systems will require a new research focus.
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Inland capture fishery contributions to global food security and threats to their future
Youn, So-Jung; Taylor, William W.; Lynch, Abigail J.; Cowx, Ian G.; Beard, T. Douglas; Bartley, Devin; Wu, Felicia
2014-01-01
Inland fish and fisheries play important roles in ensuring global food security. They provide a crucial source of animal protein and essential micronutrients for local communities, especially in the developing world. Data concerning fisheries production and consumption of freshwater fish are generally inadequately assessed, often leading decision makers to undervalue their importance. Modification of inland waterways for alternative uses of freshwater (particularly dams for hydropower and water diversions for human use) negatively impacts the productivity of inland fisheries for food security at local and regional levels. This paper highlights the importance of inland fisheries to global food security, the challenges they face due to competing demands for freshwater, and possible solutions.
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Wright, Daniel William; Nowak, Barbara; Oppedal, Frode; Crosbie, Phil; Stien, Lars Helge; Dempster, Tim
2018-06-25
Freshwater bathing is one of the main treatment options available against amoebic gill disease (AGD) affecting multiple fish hosts in mariculture systems. Prevailing freshwater treatments are designed to be long enough to kill Neoparamoeba perurans, the ectoparasite causing AGD, which may select for freshwater tolerance. Here, we tested whether using shorter, sublethal freshwater treatment durations are a viable alternative to lethal ones for N. perurans (2-4 hr). Under in vitro conditions, gill-isolated N. perurans attached to plastic substrate in sea water lifted off after ≥2 min in freshwater, but survival was not impacted until 60 min. In an in vivo experiment, AGD-affected Atlantic salmon Salmo salar subjected daily to 30 min (sublethal to N. perurans) and 120 min (lethal to N. perurans) freshwater treatments for 6 days consistently reduced N. perurans cell numbers on gills (based on qPCR analysis) compared to daily 3 min freshwater or seawater treatments for 6 days. Our results suggest that targeting cell detachment rather than cell death with repeated freshwater treatments of shorter duration than typical baths could be used in AGD management. However, the consequences of modifying the intensity of freshwater treatment regimes on freshwater tolerance evolution in N. perurans populations require careful consideration. © 2018 John Wiley & Sons Ltd.
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Linking water resources to food security through virtual water
NASA Astrophysics Data System (ADS)
Tamea, Stefania
2014-05-01
The largest use of global freshwater resources is related to food production. While each day we drink about 2 liters of water, we consume (eating) about 4000 liters of ''virtual water'', which represents the freshwater used to produce crop-based and livestock-based food. Considering human water consumption as a whole, most part originates from agriculture (85.8%), and only minor parts come from industry (9.6%) or households (4.6%). These numbers shed light on the great pressure of humanity on global freshwater resources and justify the increasing interest towards this form of environmental impact, usually known as ''water footprint''. Virtual water is a key variable in establishing the nexus between water and food. In fact, water resources used for agricultural production determine local food availability, and impact the international trade of agricultural goods. Trade, in turn, makes food commodities available to nations which are not otherwise self-sufficient, in terms of water resources or food, and it establishes an equilibrium between food demand and production at the global scale. Therefore, food security strongly relies on international food trade, but also on the use of distant and foreign water resources, which need to be acknowledged and investigated. Virtual water embedded in production and international trade follows the fate of food on the trade network, generating virtual flows of great magnitude (e.g., 2800 km3 in 2010) and defining local and global virtual water balances worldwide. The resulting water-food nexus is critical for the societal and economic development, and it has several implications ranging from population dynamics to the competing use of freshwater resources, from dietary guidelines to globalization of trade, from externalization of pollution to policy making and to socio-economic wealth. All these implications represent a great challenge for future research, not only in hydrology but in the many fields related to this interdisciplinary topic. Virtual water and water footprint accounting provide the tools for understanding such implications and to describe, quantify, and investigate the inextricable link existing between water resources and food security.
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Conrads, Paul; Edwin Roehl, Jr.
2017-01-01
Natural-resource managers and stakeholders face difficult challenges when managing interactions between natural and societal systems. Potential changes in climate could alter interactions between environmental and societal systems and adversely affect the availability of water resources in many coastal communities. The availability of freshwater in coastal streams can be threatened by saltwater intrusion. Even though the collective interests and computer skills of the community of managers, scientists and other stakeholders are quite varied, there is an overarching need for equal access by all to the scientific knowledge needed to make the best possible decisions. This paper describes a decision support system, PRISM-2, developed to evaluate salinity intrusion due to potential climate change along the South Carolina coast in southeastern USA. The decision support system is disseminated as a spreadsheet application and integrates the output of global circulation models, watershed models and salinity intrusion models with real-time databases for simulation, graphical user interfaces, and streaming displays of results. The results from PRISM-2 showed that a 31-cm and 62-cm increase in sea level reduced the daily availability of freshwater supply to a coastal municipal intake by 4% and 12% of the time, respectively. Future climate change projections by a global circulation model showed a seasonal change in salinity intrusion events from the summer to the fall for the majority of events.
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Oki, Delwyn S.
2002-01-01
An estimate of ground-water availability in the Hawi area of north Kohala, Hawaii, is needed to determine whether ground-water resources are adequate to meet future demand within the area and other areas to the south. For the Hawi area, estimated average annual recharge from infiltration of rainfall, fog drip, and irrigation is 37.5 million gallons per day from a daily water budget. Low and high annual recharge estimates for the Hawi area that incorporate estimated uncertainty are 19.9 and 55.4 million gallons per day, respectively. The recharge estimates from this study are lower than the recharge of 68.4 million gallons per day previously estimated from a monthly water budget. Three ground-water models, using the low, intermediate, and high recharge estimates (19.9, 37.5, and 55.4 million gallons per day, respectively), were developed for the Hawi area to simulate ground-water levels and discharges for the 1990?s. To assess potential ground-water availability, the numerical ground-water flow models were used to simulate the response of the freshwater-lens system to withdrawals at rates in excess of the average 1990?s withdrawal rates. Because of uncertainty in the recharge estimate, estimates of ground-water availability also are uncertain. Results from numerical simulations indicate that for appropriate well sites, depths, and withdrawal rates (1) for the low recharge estimate (19.9 million gallons per day) it may be possible to develop an additional 10 million gallons per day of fresh ground water from the Hawi area and maintain a freshwater-lens thickness of 160 feet near the withdrawal sites, (2) for the intermediate recharge estimate (37.5 million gallons per day) it may be possible to develop an additional 15 million gallons per day of fresh ground water from the Hawi area and maintain a freshwater-lens thickness of 190 feet near the withdrawal sites, and (3) for the high recharge estimate (55.4 million gallons per day) it may be possible to develop at least an additional 20 million gallons per day of fresh ground water from the Hawi area and maintain a freshwater-lens thickness of 200 feet near the withdrawal sites. Other well-field configurations than the ones considered potentially could be used to develop more fresh ground water than indicated by the scenarios tested in this study. Depth, spacing, and withdrawal rates of individual wells are important considerations in determining ground-water availability. The regional models developed for this study cannot predict whether local saltwater intrusion problems may occur at individual withdrawal sites. Results of this study underscore the importance of collecting new information to better constrain the recharge estimates.
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Ginger, Luke; Cage, Marcy; David, Kyle T.; Chakrabarty, Prosanta; Johnston, Mark; Matamoros, Wilfredo A.
2017-01-01
The distributions of many Northern Hemisphere organisms have been influenced by fluctuations in sea level and climatic conditions during Pleistocene interglacial periods. These cycles are associated with range contraction and refugia for northern-distributed organisms as a response to glaciers. However, lower sea levels in the tropics and sub-tropics created available habitat for expansion of the ranges of freshwater organisms. The goal of this study was to use ecological niche modeling to test the hypothesis of north to south range expansion of Vieja maculicauda associated with Pleistocene glacial cycles. Understanding the biogeography of this widespread species may help us better understand the geology and interconnectivity of Central American freshwaters. Occurrence data for V. maculicauda was based on georeferencing of all museum records of specimens recovered from FishNet2. General patterns of phylogeographic structure were assessed with mtDNA. Present day niche models were generated and subsequently projected onto paleoclimatic maps of the region during the Last Interglacial, Last Glacial Maximum, and mid-Holocene. Phylogenetic analysis of mtDNA sequence data showed no phylogeographic structure throughout the range of this widespread species. Present day niche models were congruent with the observed distribution of V. maculicauda in Central America. Results showed a lack of suitable freshwater habitat in northern Central America and Mexico during the Last Interglacial, with greatest range expansion during the Last Glacial Maximum and mid-Holocene. Results support the hypothesis of a north to south range expansion of V. maculicauda associated with glacial cycles. The wide distribution of this species compared to other closely related cichlids indicates the latter did not respond to the degree of V. maculicauda in expansion of their distributions. Future work aimed at comparisons with other species and modeling of future climatic scenarios will be a fruitful area of investigation. PMID:28558052
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Elías-Gutiérrez, Manuel; Valdez-Moreno, Martha; Topan, Janet; Young, Monica R; Cohuo-Colli, José Angel
2018-03-01
Currently, freshwater zooplankton sampling and identification methodologies have remained virtually unchanged since they were first established in the beginning of the XX century. One major contributing factor to this slow progress is the limited success of modern genetic methodologies, such as DNA barcoding, in several of the main groups. This study demonstrates improved protocols which enable the rapid assessment of most animal taxa inhabiting any freshwater system by combining the use of light traps, careful fixation at low temperatures using ethanol, and zooplankton-specific primers. We DNA-barcoded 2,136 specimens from a diverse array of taxonomic assemblages (rotifers, mollusks, mites, crustaceans, insects, and fishes) from several Canadian and Mexican lakes with an average sequence success rate of 85.3%. In total, 325 Barcode Index Numbers (BINs) were detected with only three BINs (two cladocerans and one copepod) shared between Canada and Mexico, suggesting a much narrower distribution range of freshwater zooplankton than previously thought. This study is the first to broadly explore the metazoan biodiversity of freshwater systems with DNA barcodes to construct a reference library that represents the first step for future programs which aim to monitor ecosystem health, track invasive species, or improve knowledge of the ecology and distribution of freshwater zooplankton.
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NASA Astrophysics Data System (ADS)
Tidwell, Vincent C.; Moreland, Barbie D.; Shaneyfelt, Calvin R.; Kobos, Peter
2018-01-01
The availability of freshwater supplies to meet future demand is a growing concern. Water availability metrics are needed to inform future water development decisions. With the help of water managers, water availability was mapped for over 1300 watersheds throughout the 31 contiguous states in the eastern US complimenting a prior study of the west. The compiled set of water availability data is unique in that it considers multiple sources of water (fresh surface and groundwater, wastewater and brackish groundwater); accommodates institutional controls placed on water use; is accompanied by cost estimates to access, treat and convey each unique source of water; and is compared to projected future growth in consumptive water use to 2030. Although few administrative limits have been set on water availability in the east, water managers have identified 315 fresh surface water and 398 fresh groundwater basins (with 151 overlapping basins) as areas of concern (AOCs) where water supply challenges exist due to drought related concerns, environmental flows, groundwater overdraft, or salt water intrusion. This highlights a difference in management where AOCs are identified in the east which simply require additional permitting, while in the west strict administrative limits are established. Although the east is generally considered ‘water rich’ roughly a quarter of the basins were identified as AOCs; however, this is still in strong contrast to the west where 78% of the surface water basins are operating at or near their administrative limit. Little effort was noted on the part of eastern or western water managers to quantify non-fresh water resources.
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The Influence of Volcanic and Solar forcings on the Freshwater Budget of the Arctic Ocean
NASA Astrophysics Data System (ADS)
Davies, F. J.; Goosse, H.; Renssen, H.
2012-04-01
In recent decades the quantity and spatial extent of measurements for the atmospheric, terrestrial and oceanic sources and sinks, that comprise the freshwater budget of the Arctic Ocean has increased. This has been driven by a need to understand the variability of the freshwater budget, as a response to anthropogenically induced climate change, and the effects upon climate. However, the natural variability of the system due to specific forcings over a number of temporal scales, is yet to be clearly defined. This is due to several factors. A lack of a reliable freshwater proxy, coupled with a truncated instrumental record, make it difficult to elicit meaningful trends from the data that is currently available. In addition, modelling studies have not taken up the opportunity to evaluate the historical freshwater budget, instead focusing all their efforts in ascertaining the future response of the system. Therefore, when it comes to understanding the role individual forcings, such as volcanic and solar, have upon the natural variability of the freshwater budget, a noticeable void is evident. In order to understand the natural variations over the recent past one has to first consider the effects that natural forcings have upon the system, both independently and simultaneously. Therefore, in this study we seek to understand the effects solar and volcanic forcings have upon the freshwater budget of the Arctic, and by association, the climate. Here we present results of a series of transient simulations spanning the last 2000 years, performed with the earth model of intermediate complexity, LOVECLIM (Goosse et al., 2010). These series of simulations use a combination of orbital parameters, greenhouse gas concentrations, total solar irradiance and volcanic forcings. By comparing the simulation with only long-term forcings (orbital and greenhouse gas), to experiments in which the impacts of short-term forcings (solar and volcanic) are added incrementally to the effect of these long-term forcings, we are able to assess to what extent solar and volcanic forcings influence the variability of the Arctic freshwater budget. Time-series analysis will be applied to the output of the different experiments to evaluate the changes in the different frequency domains. Goosse, H., Brovkin, V., Fichefet, T., Haarsma, R., Huybrechts, P., Jongma, J., Mouchet, A., Selten, F., Barriat, P-Y., Campin, J-M., Deleersnijder, E., Driesschaert, E., Goelzer, H., Janssens, I., Loutre, M-F., Morales Maqueda, M.A., Opsteegh, T., Mathieu, P-P., Munhoven, G., Pettersson., E.J., Renssen, H., Roche, D.M., Schaeffer, M., Tartinville, B., Timmermann, A., Weber, S.L. (2010) Description of the Earth System Model of Intermediate Complexity LOVECLIM Version 1.2, Geoscientific Model Development, 3:603-633 doi: 10.5194/gmd-3-603-2010.
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Craig, Laura S.; Olden, Julian D.; Arthington, Angela; Entrekin, Sally; Hawkins, Charles P.; Kelly, John J.; Kennedy, Theodore A.; Maitland, Bryan M.; Rosi, Emma J.; Roy, Allison; Strayer, David L.; Tank, Jennifer L.; West, Amie O.; Wooten, Matthew S.
2017-01-01
Human activities create threats that have consequences for freshwater ecosystems and, in most watersheds, observed ecological responses are the result of complex interactions among multiple threats and their associated ecological alterations. Here we discuss the value of considering multiple threats in research and management, offer suggestions for filling knowledge gaps, and provide guidance for addressing the urgent management challenges posed by multiple threats in freshwater ecosystems. There is a growing literature assessing responses to multiple alterations, and we build off this background to identify three areas that require greater attention: linking observed alterations to threats, understanding when and where threats overlap, and choosing metrics that best quantify the effects of multiple threats. Advancing science in these areas will help us understand existing ecosystem conditions and predict future risk from multiple threats. Because addressing the complex issues and novel ecosystems that arise from the interaction of multiple threats in freshwater ecosystems represents a significant management challenge, and the risks of management failure include loss of biodiversity, ecological goods, and ecosystem services, we also identify actions that could improve decision-making and management outcomes. These actions include drawing insights from management of individual threats, using threat attributes (e.g., causes and spatio-temporal dynamics) to identify suitable management approaches, testing management strategies that are likely to be successful despite uncertainties about the nature of interactions among threats, avoiding unintended consequences, and maximizing conservation benefits. We also acknowledge the broadly applicable challenges of decision-making within a socio-political and economic framework, and suggest that multidisciplinary teams will be needed to innovate solutions to meet the current and future challenge of interacting threats in freshwater ecosystems.
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Glacial runoff strongly influences food webs in Gulf of Alaska fjords
NASA Astrophysics Data System (ADS)
Arimitsu, M.; Piatt, J. F.; Mueter, F. J.
2015-12-01
Melting glaciers contribute large volumes of freshwater to the Gulf of Alaska coast. Rates of glacier volume loss have increased markedly in recent decades, raising concern about the eventual loss of glaciers as a source of freshwater in coastal waters. To better understand the influence of glacier melt water on fjord ecosystems, we sampled oceanography, nutrients, zooplankton, forage fish, and seabirds within four fjords in the coastal Gulf of Alaska. We used generalized additive models and geostatistics to identify the range of influence of glacier runoff in fjords of varying estuarine and topographic complexity. We also modeled the responses of chlorophyll a concentration, copepod biomass, fish and seabird abundance to physical, nutrient and biotic predictor variables. Physical and nutrient signatures of glacial runoff extended 10-20 km into coastal fjords. Glacially modified physical gradients and among-fjord differences explained 66% of the variation in phytoplankton abundance, which drives ecosystem structure at higher trophic levels. Copepod, euphausiid, fish and seabird distribution and abundance were also related to environmental gradients that could be traced to glacial freshwater input. Seabird density was predicted by prey availability and silica concentrations, which may indicate upwelling areas where this nutrient is in excess. Similarities in ecosystem structure among fjords were due to influx of cold, fresh, sediment and nutrient laden water, while differences were due to fjord topography and the relative importance of estuarine vs. ocean influences. We anticipate continued changes in the volume and magnitude of glacial runoff will affect coastal marine food webs in the future.
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Decadal-timescale estuarine geomorphic change under future scenarios of climate and sediment supply
Ganju, N.K.; Schoellhamer, D.H.
2010-01-01
Future estuarine geomorphic change, in response to climate change, sea-level rise, and watershed sediment supply, may govern ecological function, navigation, and water quality. We estimated geomorphic changes in Suisun Bay, CA, under four scenarios using a tidal-timescale hydrodynamic/sediment transport model. Computational expense and data needs were reduced using the morphological hydrograph concept and the morphological acceleration factor. The four scenarios included (1) present-day conditions; (2) sea-level rise and freshwater flow changes of 2030; (3) sea-level rise and decreased watershed sediment supply of 2030; and (4) sea-level rise, freshwater flow changes, and decreased watershed sediment supply of 2030. Sea-level rise increased water levels thereby reducing wave-induced bottom shear stress and sediment redistribution during the wind-wave season. Decreased watershed sediment supply reduced net deposition within the estuary, while minor changes in freshwater flow timing and magnitude induced the smallest overall effect. In all future scenarios, net deposition in the entire estuary and in the shallowest areas did not keep pace with sea-level rise, suggesting that intertidal and wetland areas may struggle to maintain elevation. Tidal-timescale simulations using future conditions were also used to infer changes in optical depth: though sea-level rise acts to decrease mean light irradiance, decreased suspended-sediment concentrations increase irradiance, yielding small changes in optical depth. The modeling results also assisted with the development of a dimensionless estuarine geomorphic number representing the ratio of potential sediment import forces to sediment export forces; we found the number to be linearly related to relative geomorphic change in Suisun Bay. The methods implemented here are widely applicable to evaluating future scenarios of estuarine change over decadal timescales. ?? The Author(s) 2009.
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Arctic climatechange and its impacts on the ecology of the North Atlantic.
Greene, Charles H; Pershing, Andrew J; Cronin, Thomas M; Ceci, Nicole
2008-11-01
Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global- to basin-scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends in sea ice, freshwater export, and surface ocean salinity continue. It is more difficult to predict ecological responses to abrupt climate change in the more distant future as tipping points in the Earth's climate system are exceeded.
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Jenkins, Jill A.; Jeske, Clinton W.; Allain, Larry K.
2011-01-01
The implementation of freshwater diversions in large-scale coastal restoration schemes presents several scientific and management considerations. Large-scale environmental restructuring necessitates aquatic biomonitoring, and during such field studies, photographs that document animals and habitat may be captured. Among the biomonitoring studies performed in conjunction with the Davis Pond freshwater diversion structure south of New Orleans, Louisiana, only postdiversion study images are readily available, and these are presented here.
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Developing a Resource for Implementing ArcSWAT Using Global Datasets
NASA Astrophysics Data System (ADS)
Taggart, M.; Caraballo Álvarez, I. O.; Mueller, C.; Palacios, S. L.; Schmidt, C.; Milesi, C.; Palmer-Moloney, L. J.
2015-12-01
This project developed a comprehensive user manual outlining methods for adapting and implementing global datasets for use within ArcSWAT for international and worldwide applications. The Soil and Water Assessment Tool (SWAT) is a hydrologic model that looks at a number of hydrologic variables including runoff and the chemical makeup of water at a given location on the Earth's surface using Digital Elevation Models (DEM), land cover, soil, and weather data. However, the application of ArcSWAT for projects outside of the United States is challenging as there is no standard framework for inputting global datasets into ArcSWAT. This project aims to remove this obstacle by outlining methods for adapting and implementing these global datasets via the user manual. The manual takes the user through the processes of data conditioning while providing solutions and suggestions for common errors. The efficacy of the manual was explored using examples from watersheds located in Puerto Rico, Mexico and Western Africa. Each run explored the various options for setting up a ArcSWAT project as well as a range of satellite data products and soil databases. Future work will incorporate in-situ data for validation and calibration of the model and outline additional resources to assist future users in efficiently implementing the model for worldwide applications. The capacity to manage and monitor freshwater availability is of critical importance in both developed and developing countries. As populations grow and climate changes, both the quality and quantity of freshwater are affected resulting in negative impacts on the health of the surrounding population. The use of hydrologic models such as ArcSWAT can help stakeholders and decision makers understand the future impacts of these changes enabling informed and substantiated decisions.
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Prospects for monitoring freshwater ecosystems towards the 2010 targets
Revenga, C; Campbell, I; Abell, R; de Villiers, P; Bryer, M
2005-01-01
Human activities have severely affected the condition of freshwater ecosystems worldwide. Physical alteration, habitat loss, water withdrawal, pollution, overexploitation and the introduction of non-native species all contribute to the decline in freshwater species. Today, freshwater species are, in general, at higher risk of extinction than those in forests, grasslands and coastal ecosystems. For North America alone, the projected extinction rate for freshwater fauna is five times greater than that for terrestrial fauna—a rate comparable to the species loss in tropical rainforest. Because many of these extinctions go unseen, the level of assessment and knowledge of the status and trends of freshwater species are still very poor, with species going extinct before they are even taxonomically classified. Increasing human population growth and achieving the sustainable development targets set forth in 2002 will place even higher demands on the already stressed freshwater ecosystems, unless an integrated approach to managing water for people and ecosystems is implemented by a broad constituency. To inform and implement policies that support an integrated approach to water management, as well as to measure progress in halting the rapid decline in freshwater species, basin-level indicators describing the condition and threats to freshwater ecosystems and species are required. This paper discusses the extent and quality of data available on the number and size of populations of freshwater species, as well as the change in the extent and condition of natural freshwater habitats. The paper presents indicators that can be applied at multiple scales, highlighting the usefulness of using remote sensing and geographical information systems technologies to fill some of the existing information gaps. Finally, the paper includes an analysis of major data gaps and information needs with respect to freshwater species to measure progress towards the 2010 biodiversity targets. PMID:15814353
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Adaptive management in the context of barriers in European freshwater ecosystems.
Birnie-Gauvin, Kim; Tummers, Jeroen S; Lucas, Martyn C; Aarestrup, Kim
2017-12-15
Many natural habitats have been modified to accommodate for the presence of humans and their needs. Infrastructures - such as hydroelectric dams, weirs, culverts and bridges - are now a common occurrence in streams and rivers across the world. As a result, freshwater ecosystems have been altered extensively, affecting both biological and geomorphological components of the habitats. Many fish species rely on these freshwater ecosystems to complete their lifecycles, and the presence of barriers has been shown to reduce their ability to migrate and sustain healthy populations. In the long run, barriers may have severe repercussions on population densities and dynamics of aquatic animal species. There is currently an urgent need to address these issues with adequate conservation approaches. Adaptive management provides a relevant approach to managing barriers in freshwater ecosystems as it addresses the uncertainties of dealing with natural systems, and accommodates for future unexpected events, though this approach may not be suitable in all instances. A literature search on this subject yielded virtually no output. Hence, we propose a step-by-step guide for implementing adaptive management, which could be used to manage freshwater barriers. Copyright © 2017 Elsevier Ltd. All rights reserved.
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A Guide to the Natural History of Freshwater Lake Bacteria†
Newton, Ryan J.; Jones, Stuart E.; Eiler, Alexander; McMahon, Katherine D.; Bertilsson, Stefan
2011-01-01
Summary: Freshwater bacteria are at the hub of biogeochemical cycles and control water quality in lakes. Despite this, little is known about the identity and ecology of functionally significant lake bacteria. Molecular studies have identified many abundant lake bacteria, but there is a large variation in the taxonomic or phylogenetic breadths among the methods used for this exploration. Because of this, an inconsistent and overlapping naming structure has developed for freshwater bacteria, creating a significant obstacle to identifying coherent ecological traits among these groups. A discourse that unites the field is sorely needed. Here we present a new freshwater lake phylogeny constructed from all published 16S rRNA gene sequences from lake epilimnia and propose a unifying vocabulary to discuss freshwater taxa. With this new vocabulary in place, we review the current information on the ecology, ecophysiology, and distribution of lake bacteria and highlight newly identified phylotypes. In the second part of our review, we conduct meta-analyses on the compiled data, identifying distribution patterns for bacterial phylotypes among biomes and across environmental gradients in lakes. We conclude by emphasizing the role that this review can play in providing a coherent framework for future studies. PMID:21372319
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Biota connect aquatic habitats throughout freshwater ecosystem mosaics
Schofield, Kate A.; Alexander, Laurie C.; Ridley, Caroline E.; Vanderhoof, Melanie; Fritz, Ken M.; Autrey, Bradley; DeMeester, Julie; Kepner, William G.; Lane, Charles R.; Leibowitz, Scott; Pollard, Amina I.
2018-01-01
Freshwater ecosystems are linked at various spatial and temporal scales by movements of biota adapted to life in water. We review the literature on movements of aquatic organisms that connect different types of freshwater habitats, focusing on linkages from streams and wetlands to downstream waters. Here, streams, wetlands, rivers, lakes, ponds, and other freshwater habitats are viewed as dynamic freshwater ecosystem mosaics (FEMs) that collectively provide the resources needed to sustain aquatic life. Based on existing evidence, it is clear that biotic linkages throughout FEMs have important consequences for biological integrity and biodiversity. All aquatic organisms move within and among FEM components, but differ in the mode, frequency, distance, and timing of their movements. These movements allow biota to recolonize habitats, avoid inbreeding, escape stressors, locate mates, and acquire resources. Cumulatively, these individual movements connect populations within and among FEMs and contribute to local and regional diversity, resilience to disturbance, and persistence of aquatic species in the face of environmental change. Thus, the biological connections established by movement of biota among streams, wetlands, and downstream waters are critical to the ecological integrity of these systems. Future research will help advance our understanding of the movements that link FEMs and their cumulative effects on downstream waters.
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Assessing exposure risks for freshwater tilapia species posed by mercury and methylmercury.
Cheng, Yi-Hsien; Lin, Yi-Jun; You, Shu-Han; Yang, Ying-Fei; How, Chun Ming; Tseng, Yi-Ting; Chen, Wei-Yu; Liao, Chung-Min
2016-08-01
Waterborne and dietborne exposures of freshwater fish to mercury (Hg) in the forms of inorganic (Hg(II)) and organic (methylmercury or MeHg) affect their growth, development, and reproduction. However, an integrated mechanistic risk model framework to predict the impact of Hg(II)/MeHg on freshwater fish is lacking. Here, we integrated biokinetic, physiological and biogeographic data to calibrate and then establish key risk indices-hazardous quotient and exceedance risk-for freshwater tilapia species across geographic ranges of several major rivers in Taiwan. We found that Hg(II) burden was highest in kidney followed by gill, intestine, liver, blood, and muscle. Our results showed that Hg was less likely to pose mortality risk (mortality rate less than 5 %) for freshwater tilapia species. However, Hg is likely to pose the potential hazard to aquatic environments constrained by safety levels for aquatic organisms. Sensitivity analysis showed that amount of Hg accumulated in tilapia was most influenced by sediment uptake rate. Our approach opens up new possibilities for predicting future fish population health with the impacts of continued Hg exposure to provide information on which fish are deemed safe for human consumption.
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Mechanistic understanding of sunlight-induced natural processes for
production of dissolved gaseous mercury (DGM) in freshwaters has remained
limited, and few direct field tests of the mechanistic hypotheses are available.
We exposed ferric iron salt-spiked fresh s... -
On the representation of subsea aquitards in models of offshore fresh groundwater
NASA Astrophysics Data System (ADS)
Solórzano-Rivas, S. C.; Werner, A. D.
2018-02-01
Fresh groundwater is widespread globally in offshore aquifers, and is particularly dependent on the properties of offshore aquitards, which inhibit seawater-freshwater mixing thereby allowing offshore freshwater to persist. However, little is known of the salinity distribution in subsea aquitards, especially in relation to the offshore freshwater distribution. This is critical for the application of recent analytical solutions to subsea freshwater extent given requisite assumptions about aquitard salinity. In this paper, we use numerical simulation to explore the extent of offshore freshwater in simplified situations of subsea aquifers and overlying aquitards, including in relation to the upward leakage of freshwater. The results show that available analytical solutions significantly overestimate the offshore extent of upwelling freshwater due to the presumption of seawater in the aquitard, whereas the seawater wedge toe is less sensitive to the assumed aquitard salinity. We also explore the use of implicit, conductance-based representations of the aquitard (i.e., using the popular SEAWAT code), and find that SEAWAT's implicit approach (i.e., GHB package) can represent the offshore distance of upwelling freshwater using a novel parameterization strategy. The results show that an estimate of the upward freshwater flow that is required to freshen the aquitard is associated with the dimensionless Rayleigh number, whereby the critical Rayleigh number that distinguishes fresh and saline regions (based on the position of the 0.5 isochlor) within the aquitard is approximately 2.
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The First Detailed 2H and 18O Isoscapes of Freshwater in Scotland
NASA Astrophysics Data System (ADS)
Meier-Augenstein, W.; Hoogewerff, J.; Kemp, H. F.; Frew, D.
2012-04-01
Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwater quality by the Scottish Environmental Protection Agency (SEPA) fulfils the legislative requirements but new scientific methods involving stable isotope analysis present an opportunity for delivering on current and nascent government policies [1] and gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and the aforementioned functions. In brief, 2H and 18O isoscapes of Scottish freshwater could be used to support fundamental and applied research in: • Climate change - These first ever isoscapes will provide a baseline against which future environmental impact can be assessed due to changes in the characteristic isotope composition of freshwater lochs and reservoirs. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish berries and Scottish Whisky. During 2011, freshwater samples were collected with the support of SEPA from more than 80 freshwater lochs and reservoirs across Scotland. Here we present the result of the 2H and 18O stable isotope analyses of these water samples together with the first isoscapes generated based on these data. [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland's National Food and Drink Policy (2009); Scottish Planning Policy Environmental Report (2009); Scottish Planning Policy (SPP) 15 Planning for Rural Development (2005); National Planning Policy Guideline (NPPG) 14: Natural Heritage (1999).
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Anthropogenic Litter in Urban Freshwater Ecosystems: Distribution and Microbial Interactions
Hoellein, Timothy; Rojas, Miguel; Pink, Adam; Gasior, Joseph; Kelly, John
2014-01-01
Accumulation of anthropogenic litter (i.e. garbage; AL) and its ecosystem effects in marine environments are well documented. Rivers receive AL from terrestrial habitats and represent a major source of AL to marine environments, but AL is rarely studied within freshwater ecosystems. Our objectives were to 1) quantify AL density in urban freshwaters, 2) compare AL abundance among freshwater, terrestrial, and marine ecosystems, and 3) characterize the activity and composition of AL biofilms in freshwater habitats. We quantified AL from the Chicago River and Chicago's Lake Michigan shoreline, and found that AL abundance in Chicago freshwater ecosystems was comparable to previously reported data for marine and terrestrial ecosystems, although AL density and composition differed among habitats. To assess microbial interactions with AL, we incubated AL and natural substrates in 3 freshwater ecosystems, quantified biofilm metabolism as gross primary production (GPP) and community respiration (CR), and characterized biofilm bacterial community composition via high-throughput sequencing of 16S rRNA genes. The main driver of biofilm community composition was incubation location (e.g., river vs pond), but there were some significant differences in biofilm composition and metabolism among substrates. For example, biofilms on organic substrates (cardboard and leaves) had lower GPP than hard substrates (glass, plastic, aluminum and tiles). In addition, bacterial communities on organic substrates were distinct in composition from those on hard substrates, with higher relative abundances of bacteria associated with cellulose decomposition. Finally, we used our results to develop a conceptual diagram designed to unite the study of AL in terrestrial and freshwater environments with the well-established field of marine debris research. We suggest this broad perspective will be useful for future studies which synthesize AL sources, ecosystem effects, and fate across multiple ecosystem types, and will benefit management and reduction of global AL accumulations. PMID:24955768
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Anthropogenic litter in urban freshwater ecosystems: distribution and microbial interactions.
Hoellein, Timothy; Rojas, Miguel; Pink, Adam; Gasior, Joseph; Kelly, John
2014-01-01
Accumulation of anthropogenic litter (i.e. garbage; AL) and its ecosystem effects in marine environments are well documented. Rivers receive AL from terrestrial habitats and represent a major source of AL to marine environments, but AL is rarely studied within freshwater ecosystems. Our objectives were to 1) quantify AL density in urban freshwaters, 2) compare AL abundance among freshwater, terrestrial, and marine ecosystems, and 3) characterize the activity and composition of AL biofilms in freshwater habitats. We quantified AL from the Chicago River and Chicago's Lake Michigan shoreline, and found that AL abundance in Chicago freshwater ecosystems was comparable to previously reported data for marine and terrestrial ecosystems, although AL density and composition differed among habitats. To assess microbial interactions with AL, we incubated AL and natural substrates in 3 freshwater ecosystems, quantified biofilm metabolism as gross primary production (GPP) and community respiration (CR), and characterized biofilm bacterial community composition via high-throughput sequencing of 16S rRNA genes. The main driver of biofilm community composition was incubation location (e.g., river vs pond), but there were some significant differences in biofilm composition and metabolism among substrates. For example, biofilms on organic substrates (cardboard and leaves) had lower GPP than hard substrates (glass, plastic, aluminum and tiles). In addition, bacterial communities on organic substrates were distinct in composition from those on hard substrates, with higher relative abundances of bacteria associated with cellulose decomposition. Finally, we used our results to develop a conceptual diagram designed to unite the study of AL in terrestrial and freshwater environments with the well-established field of marine debris research. We suggest this broad perspective will be useful for future studies which synthesize AL sources, ecosystem effects, and fate across multiple ecosystem types, and will benefit management and reduction of global AL accumulations.
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Vulnerability of European freshwater catchments to climate change.
Markovic, Danijela; Carrizo, Savrina F; Kärcher, Oskar; Walz, Ariane; David, Jonathan N W
2017-09-01
Climate change is expected to exacerbate the current threats to freshwater ecosystems, yet multifaceted studies on the potential impacts of climate change on freshwater biodiversity at scales that inform management planning are lacking. The aim of this study was to fill this void through the development of a novel framework for assessing climate change vulnerability tailored to freshwater ecosystems. The three dimensions of climate change vulnerability are as follows: (i) exposure to climate change, (ii) sensitivity to altered environmental conditions and (iii) resilience potential. Our vulnerability framework includes 1685 freshwater species of plants, fishes, molluscs, odonates, amphibians, crayfish and turtles alongside key features within and between catchments, such as topography and connectivity. Several methodologies were used to combine these dimensions across a variety of future climate change models and scenarios. The resulting indices were overlaid to assess the vulnerability of European freshwater ecosystems at the catchment scale (18 783 catchments). The Balkan Lakes Ohrid and Prespa and Mediterranean islands emerge as most vulnerable to climate change. For the 2030s, we showed a consensus among the applied methods whereby up to 573 lake and river catchments are highly vulnerable to climate change. The anthropogenic disruption of hydrological habitat connectivity by dams is the major factor reducing climate change resilience. A gap analysis demonstrated that the current European protected area network covers <25% of the most vulnerable catchments. Practical steps need to be taken to ensure the persistence of freshwater biodiversity under climate change. Priority should be placed on enhancing stakeholder cooperation at the major basin scale towards preventing further degradation of freshwater ecosystems and maintaining connectivity among catchments. The catchments identified as most vulnerable to climate change provide preliminary targets for development of climate change conservation management and mitigation strategies. © 2017 John Wiley & Sons Ltd.
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Bistability of mangrove forests and competition with freshwater plants
Jiang, Jiang; Fuller, Douglas O; Teh, Su Yean; Zhai, Lu; Koh, Hock Lye; DeAngelis, Donald L.; Sternberg, L.D.S.L.
2015-01-01
Halophytic communities such as mangrove forests and buttonwood hammocks tend to border freshwater plant communities as sharp ecotones. Most studies attribute this purely to underlying physical templates, such as groundwater salinity gradients caused by tidal flux and topography. However, a few recent studies hypothesize that self-reinforcing feedback between vegetation and vadose zone salinity are also involved and create a bistable situation in which either halophytic dominated habitat or freshwater plant communities may dominate as alternative stable states. Here, we revisit the bistability hypothesis and demonstrate the mechanisms that result in bistability. We demonstrate with remote sensing imagery the sharp boundaries between freshwater hardwood hammock communities in southern Florida and halophytic communities such as buttonwood hammocks and mangroves. We further document from the literature how transpiration of mangroves and freshwater plants respond differently to vadose zone salinity, thus altering the salinity through feedback. Using mathematical models, we show how the self-reinforcing feedback, together with physical template, controls the ecotones between halophytic and freshwater communities. Regions of bistability along environmental gradients of salinity have the potential for large-scale vegetation shifts following pulse disturbances such as hurricane tidal surges in Florida, or tsunamis in other regions. The size of the region of bistability can be large for low-lying coastal habitat due to the saline water table, which extends inland due to salinity intrusion. We suggest coupling ecological and hydrologic processes as a framework for future studies.
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Origins of Semisulcospira libertina (gastropoda: semisulcospiridae) in Taiwan.
Chiu, Yuh-Wen; Bor, Hor; Kuo, Po-Hsun; Hsu, Kui-Ching; Tan, Mian-Shin; Wang, Wei-Kuang; Lin, Hung-Du
2017-07-01
The most accepted hypothesis has suggested that the fauna in Taiwan Island originated from South China, but some studies supported the Japan, Ryukyu Archipelago, and Taiwan Islands as a unique biogeographical district. This study examines whether the populations of freshwater snail Semisulcospira libertina in Taiwan are closer to those in Japan based on the mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. Our study shows the populations in North Taiwan originated from Japan and the cyclic glacial caused the migrations among islands and continent repeatedly; the populations in South Taiwan might originate from South China or South Asia. Our results will not only affect the conclusions in phylogeography of freshwater species in Taiwan but also change the sampling plans in the future studies about evolutionary of freshwater species in East Asia.
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Climatic vulnerability of the world’s freshwater and marine fishes
NASA Astrophysics Data System (ADS)
Comte, Lise; Olden, Julian D.
2017-10-01
Climate change is a mounting threat to biological diversity, compromising ecosystem structure and function, and undermining the delivery of essential services worldwide. As the magnitude and speed of climate change accelerates, greater understanding of the taxonomy and geography of climatic vulnerability is critical to guide effective conservation action. However, many uncertainties remain regarding the degree and variability of climatic risk within entire clades and across vast ecosystem boundaries. Here we integrate physiological estimates of thermal sensitivity for 2,960 ray-finned fishes with future climatic exposure, and demonstrate that global patterns of vulnerability differ substantially between freshwater and marine realms. Our results suggest that climatic vulnerability for freshwater faunas will be predominantly determined by elevated levels of climatic exposure predicted for the Northern Hemisphere, whereas marine faunas in the tropics will be the most at risk, reflecting their higher intrinsic sensitivity. Spatial overlap between areas of high physiological risk and high human impacts, together with evidence of low past rates of evolution in upper thermal tolerance, highlights the urgency of global conservation actions and policy initiatives if harmful climate effects on the world’s fishes are to be mitigated in the future.
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Assessment of water availability and demand in Lake Guiers , Senegal.
NASA Astrophysics Data System (ADS)
Sambou, D.; Weihrauch, D.; Hellwing, V.; Diekkrüger, B.; Höllermann, B.; Gaye, A. T.
2015-12-01
Assessment of water availability and demand in Lake Guiers, SenegalWater resources are critical to economic growth and social development. In most African countries, supply of drinking water to satisfy population needs is a key issue because of population growth and climate and land use change. During the last three decades, increasing population, changing patterns of water demand, and concentration of population and economic activities in urban areas has pressurize Senegal's freshwater resources. To overcome this deficit, Senegal turned, to the exploitation of the Lake Guiers. It is the sole water reservoir which can be used extensively as a stable freshwater. Its water is use for irrigating crops and sugar refinery and as a drinking water resource for urban centres, including Dakar, the capital city of Senegal, as well as for the local population and animal herds. To ensure sustainability, a greater understanding of Lake Guiers's water resources and effective management of its use will be required. In this study we developed and quantified future water situation (water availability and demand) in Lake Guiers under scenarios of climate change and population growth until 2050, using the water management model WEAP (Water Evaluation And Planning system). The results show that the pressure on Lake Guiers's water resources will increase, leading to greater competition between agriculture and municipal demand site. Decreasing inflows due to climate change will aggravate this situation. WEAP results offer basis to assister lake Guiers water resources manager for an efficient long-term planning and management. Keywords: climate change, population growth , IWRM, Lake Guiers, Senegal
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Swanson, Kathleen M.; Drexler, Judith Z.; Fuller, Christopher C.; Schoellhamer, David H.
2015-01-01
In this paper, we report on the adaptation and application of a one-dimensional marsh surface elevation model, the Wetland Accretion Rate Model of Ecosystem Resilience (WARMER), to explore the conditions that lead to sustainable tidal freshwater marshes in the Sacramento–San Joaquin Delta. We defined marsh accretion parameters to encapsulate the range of observed values over historic and modern time-scales based on measurements from four marshes in high and low energy fluvial environments as well as possible future trends in sediment supply and mean sea level. A sensitivity analysis of 450 simulations was conducted encompassing a range of eScholarship provides open access, scholarly publishing services to the University of California and delivers a dynamic research platform to scholars worldwide. porosity values, initial elevations, organic and inorganic matter accumulation rates, and sea-level rise rates. For the range of inputs considered, the magnitude of SLR over the next century was the primary driver of marsh surface elevation change. Sediment supply was the secondary control. More than 84% of the scenarios resulted in sustainable marshes with 88 cm of SLR by 2100, but only 32% and 11% of the scenarios resulted in surviving marshes when SLR was increased to 133 cm and 179 cm, respectively. Marshes situated in high-energy zones were marginally more resilient than those in low-energy zones because of their higher inorganic sediment supply. Overall, the results from this modeling exercise suggest that marshes at the upstream reaches of the Delta—where SLR may be attenuated—and high energy marshes along major channels with high inorganic sediment accumulation rates will be more resilient to global SLR in excess of 88 cm over the next century than their downstream and low-energy counterparts. However, considerable uncertainties exist in the projected rates of sea-level rise and sediment avail-ability. In addition, more research is needed to constrain future rates of aboveground and belowground plant productivity under increased CO2 concentrations and flooding.
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Restricted-Range Fishes and the Conservation of Brazilian Freshwaters
Nogueira, Cristiano; Buckup, Paulo A.; Menezes, Naercio A.; Oyakawa, Osvaldo T.; Kasecker, Thais P.; Ramos Neto, Mario B.; da Silva, José Maria C.
2010-01-01
Background Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms) and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geographic resolution. Brazil harbors the richest freshwater ichthyofauna in the world, but knowledge on endemic areas and conservation in Brazilian rivers is still scarce. Methodology/Principal Findings Using data on environmental threats and revised species distribution data we detect and delineate 540 small watershed areas harboring 819 restricted-range fishes in Brazil. Many of these areas are already highly threatened, as 159 (29%) watersheds have lost more than 70% of their original vegetation cover, and only 141 (26%) show significant overlap with formally protected areas or indigenous lands. We detected 220 (40%) critical watersheds overlapping hydroelectric dams or showing both poor formal protection and widespread habitat loss; these sites harbor 344 endemic fish species that may face extinction if no conservation action is in place in the near future. Conclusions/Significance We provide the first analysis of site-scale conservation priorities in the richest freshwater ecosystems of the globe. Our results corroborate the hypothesis that freshwater biodiversity has been neglected in former conservation assessments. The study provides a simple and straightforward method for detecting freshwater priority areas based on endemism and threat, and represents a starting point for integrating freshwater and terrestrial conservation in representative and biogeographically consistent site-scale conservation strategies, that may be scaled-up following naturally linked drainage systems. Proper management (e. g. forestry code enforcement, landscape planning) and conservation (e. g. formal protection) of the 540 watersheds detected herein will be decisive in avoiding species extinction in the richest aquatic ecosystems on the planet. PMID:20613986
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Restricted-range fishes and the conservation of Brazilian freshwaters.
Nogueira, Cristiano; Buckup, Paulo A; Menezes, Naercio A; Oyakawa, Osvaldo T; Kasecker, Thais P; Ramos Neto, Mario B; da Silva, José Maria C
2010-06-30
Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms) and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geographic resolution. Brazil harbors the richest freshwater ichthyofauna in the world, but knowledge on endemic areas and conservation in Brazilian rivers is still scarce. Using data on environmental threats and revised species distribution data we detect and delineate 540 small watershed areas harboring 819 restricted-range fishes in Brazil. Many of these areas are already highly threatened, as 159 (29%) watersheds have lost more than 70% of their original vegetation cover, and only 141 (26%) show significant overlap with formally protected areas or indigenous lands. We detected 220 (40%) critical watersheds overlapping hydroelectric dams or showing both poor formal protection and widespread habitat loss; these sites harbor 344 endemic fish species that may face extinction if no conservation action is in place in the near future. We provide the first analysis of site-scale conservation priorities in the richest freshwater ecosystems of the globe. Our results corroborate the hypothesis that freshwater biodiversity has been neglected in former conservation assessments. The study provides a simple and straightforward method for detecting freshwater priority areas based on endemism and threat, and represents a starting point for integrating freshwater and terrestrial conservation in representative and biogeographically consistent site-scale conservation strategies, that may be scaled-up following naturally linked drainage systems. Proper management (e. g. forestry code enforcement, landscape planning) and conservation (e. g. formal protection) of the 540 watersheds detected herein will be decisive in avoiding species extinction in the richest aquatic ecosystems on the planet.
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Tidwell, Vincent; Moreland, Barbara D.; Shaneyfelt, Calvin; ...
2017-11-08
The availability of freshwater supplies to meet future demand is a growing concern. Water availability metrics are needed to inform future water development decisions. Furthermore, with the help of water managers, water availability was mapped for over 1300 watersheds throughout the 31-contiguous states in the eastern U.S. complimenting a prior study of the west. The compiled set of water availability data is unique in that it considers multiple sources of water (fresh surface and groundwater, wastewater and brackish groundwater); accommodates institutional controls placed on water use; is accompanied by cost estimates to access, treat and convey each unique source ofmore » water, and; is compared to projected future growth in consumptive water use to 2030. Although few administrative limits have been set on water availability in the east, water managers have identified 315 fresh surface water and 398 fresh groundwater basins (with 151 overlapping basins) as Areas of Concern (AOCs) where water supply challenges exist due to drought related concerns, environmental flows, groundwater overdraft, or salt water intrusion. This highlights a difference in management where AOCs are identified in the east which simply require additional permitting, while in the west strict administrative limits are established. Although the east is generally considered "water rich" roughly a quarter of the basins were identified as AOCs; however, this is still in strong contrast to the west where 78% of the surface water basins are operating at or near their administrative limit. There was little effort noted on the part of eastern or western water managers to quantify non-fresh water resources.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Tidwell, Vincent; Moreland, Barbara D.; Shaneyfelt, Calvin
The availability of freshwater supplies to meet future demand is a growing concern. Water availability metrics are needed to inform future water development decisions. Furthermore, with the help of water managers, water availability was mapped for over 1300 watersheds throughout the 31-contiguous states in the eastern U.S. complimenting a prior study of the west. The compiled set of water availability data is unique in that it considers multiple sources of water (fresh surface and groundwater, wastewater and brackish groundwater); accommodates institutional controls placed on water use; is accompanied by cost estimates to access, treat and convey each unique source ofmore » water, and; is compared to projected future growth in consumptive water use to 2030. Although few administrative limits have been set on water availability in the east, water managers have identified 315 fresh surface water and 398 fresh groundwater basins (with 151 overlapping basins) as Areas of Concern (AOCs) where water supply challenges exist due to drought related concerns, environmental flows, groundwater overdraft, or salt water intrusion. This highlights a difference in management where AOCs are identified in the east which simply require additional permitting, while in the west strict administrative limits are established. Although the east is generally considered "water rich" roughly a quarter of the basins were identified as AOCs; however, this is still in strong contrast to the west where 78% of the surface water basins are operating at or near their administrative limit. There was little effort noted on the part of eastern or western water managers to quantify non-fresh water resources.« less
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March, F.A.; Dwyer, F.J.; Augspurger, T.; Ingersoll, C.G.; Wang, N.; Mebane, C.A.
2007-01-01
The state of Oklahoma has designated several areas as freshwater mussel sanctuaries in an attempt to provide freshwater mussel species a degree of protection and to facilitate their reproduction. We evaluated the protection afforded freshwater mussels by the U.S. Environmental Protection Agency (U.S. EPA) hardness-based 1996 ambient copper water quality criteria, the 2007 U.S. EPA water quality criteria based on the biotic ligand model and the 2005 state of Oklahoma copper water quality standards. Both the criterion maximum concentration and criterion continuous concentration were evaluated. Published acute and chronic copper toxicity data that met American Society for Testing and Materials guidance for test acceptability were obtained for exposures conducted with glochidia or juvenile freshwater mussels. We tabulated toxicity data for glochidia and juveniles to calculate 20 species mean acute values for freshwater mussels. Generally, freshwater mussel species mean acute values were similar to those of the more sensitive species included in the U.S. EPA water quality derivation database. When added to the database of genus mean acute values used in deriving 1996 copper water quality criteria, 14 freshwater mussel genus mean acute values included 10 of the lowest 15 genus mean acute values, with three mussel species having the lowest values. Chronic exposure and sublethal effects freshwater mussel data available for four species and acute to chronic ratios were used to evaluate the criterion continuous concentration. On the basis of the freshwater mussel toxicity data used in this assessment, the hardness-based 1996 U.S. EPA water quality criteria, the 2005 Oklahoma water quality standards, and the 2007 U.S. EPA water quality criteria based on the biotic ligand model might need to be revised to afford protection to freshwater mussels. ?? 2007 SETAC.
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USDA-ARS?s Scientific Manuscript database
Freshwater prawn Macrobrachium rosenbergii culture in the Western Hemisphere is primarily, if not entirely, based on thirty-six individual prawn introduced to Hawaii from Malaysia in 1965 and 1966. Little information is available regarding the genetic background or current population status of cult...
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Night-time lights as a proxy of human pressure on freshwater resources
NASA Astrophysics Data System (ADS)
Ceola, Serena; Montanari, Alberto; Laio, Francesco
2017-04-01
The presence and availability of freshwater resources at the global scale control the dynamics and the biodiversity of river ecosystems, as well as the human development and the security of people and economies. The increasing human pressure on freshwater is known to potentially drive significant alterations on both ecohydrological and social dynamics. To date, a spatially-detailed snapshot (i.e. single in time) analysis of human water security and river biodiversity threats revealed that the majority of the world's population and river ecosystems are exposed to high levels of endangerment. However, the temporal evolution of these effects at the global scale is still unexplored. To this aim, moving from the recent progress on remote sensing techniques, we employed yearly averaged night-time light images available from 1992 to 2013 as a proxy of anthropogenic presence and activity and we investigated how threats to human water security and river biodiversity evolved in time in 405 major river basins. Our results show a consistent correlation between nightlights and ecohydrological and threats, providing innovative support for freshwater resources management.
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Heathwaite, A.L.; Johnes, P.J.; Peters, N.E.
1996-01-01
The roles of nitrogen (N) and phosphorus (P) as key nutrients determining the trophic status of water bodies are examined, and evidence reviewed for trends in concentrations of N and P species which occur in freshwaters, primarily in northern temperate environments. Data are reported for water bodies undergoing eutrophication and acidification, especially water bodies receiving increased nitrogen inputs through the atmospheric deposition of nitrogen oxides (NOx). Nutrient loading on groundwaters and surface freshwaters is assessed with respect to causes and rates of (change, relative rates of change for N and P, and implications of change for the future management of lakes, rivers and groundwaters. In particular, the nature and emphasis of studies for N species and P fractions in lakes versus rivers and groundwaters are contrasted. This review paper primarily focuses on results from North America and Europe, particularly for the UK where a wide range of data sets exists. Few nutrient loading data have been published on water bodies in less developed countries; however, some of the available data are presented to provide a global perspective. In general, N and P concentrations have increased dramatically (>20 times background concentrations) in many areas and causes vary considerably, ranging from urbanization to changes in agricultural practices.
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Organic carbon in glacial fjords of Chilean Patagonia
NASA Astrophysics Data System (ADS)
Pantoja, Silvio; Gutiérrez, Marcelo; Tapia, Fabián; Abarzúa, Leslie; Daneri, Giovanni; Reid, Brian; Díez, Beatriz
2016-04-01
The Southern Ice Field in Chilean Patagonia is the largest (13,000 km2) temperate ice mass in the Southern hemisphere, yearly transporting ca. 40 km3 of freshwater to fjords. This volume of fresh and cold water likely affects adjacent marine ecosystems by changing circulation, productivity, food web dynamics, and the abundance and distribution of planktonic and benthic organisms. We hypothesize that freshwater-driven availability of inorganic nutrient and transport of organic and inorganic suspended matter, as well as microbes, become a controlling factor for productivity in the fjord associated with the Baker river and Jorge Montt glacier. Both appear to be sources of silicic acid, but not of nitrate and particulate organic carbon, especially during summer, when surface PAR and glacier thawing are maximal. In contrast to Baker River, the Jorge Montt glacier is also a source of dissolved organic carbon towards a proglacial fjord and the Baker Channel, indicating that a thorough chemical description of sources (tidewater glacier and glacial river) is needed. Nitrate in fiord waters reaches ca. 15 μM at 25 m depth with no evidence of mixing up during summer. Stable isotope composition of particulate organic nitrogen reaches values as low as 3 per mil in low-salinity waters near both glacier and river. Nitrogen fixation could be depleting δ15N in organic matter, as suggested by the detection at surface waters of nif H genes belonging to diazotrophs near the Montt glacier. As diazotrophs have also been detected in other cold marine waters (e.g. Baltic Sea, Arctic Ocean) as well as glaciers and polar terrestrial waters, there is certainly a potential for both marine and freshwater microbes to contribute and have a significant impact on the Patagonian N and C budgets. Assessing the impact of freshwater on C and N fluxes and the microbial community structure in Patagonian waters will allow understanding future scenarios of rapid glacier melting. This research was funded by COPAS Sur-Austral (PFB-31).
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Gibson, C.A.; Meyer, J.L.; Poff, N.L.; Hay, L.E.; Georgakakos, A.
2005-01-01
We examined impacts of future climate scenarios on flow regimes and how predicted changes might affect river ecosystems. We examined two case studies: Cle Elum River, Washington, and Chattahoochee-Apalachicola River Basin, Georgia and Florida. These rivers had available downscaled global circulation model (GCM) data and allowed us to analyse the effects of future climate scenarios on rivers with (1) different hydrographs, (2) high future water demands, and (3) a river-floodplain system. We compared observed flow regimes to those predicted under future climate scenarios to describe the extent and type of changes predicted to occur. Daily stream flow under future climate scenarios was created by either statistically downscaling GCMs (Cle Elum) or creating a regression model between climatological parameters predicted from GCMs and stream flow (Chattahoochee-Apalachicola). Flow regimes were examined for changes from current conditions with respect to ecologically relevant features including the magnitude and timing of minimum and maximum flows. The Cle Elum's hydrograph under future climate scenarios showed a dramatic shift in the timing of peak flows and lower low flow of a longer duration. These changes could mean higher summer water temperatures, lower summer dissolved oxygen, and reduced survival of larval fishes. The Chattahoochee-Apalachicola basin is heavily impacted by dams and water withdrawals for human consumption; therefore, we made comparisons between pre-large dam conditions, current conditions, current conditions with future demand, and future climate scenarios with future demand to separate climate change effects and other anthropogenic impacts. Dam construction, future climate, and future demand decreased the flow variability of the river. In addition, minimum flows were lower under future climate scenarios. These changes could decrease the connectivity of the channel and the floodplain, decrease habitat availability, and potentially lower the ability of the river to assimilate wastewater treatment plant effluent. Our study illustrates the types of changes that river ecosystems might experience under future climates. Copyright ?? 2005 John Wiley & Sons, Ltd.
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Impacts of climate variability and future climate change on harmful algal blooms and human health
Stephanie K. Moore; Vera L. Trainer; Nathan J. Mantua; Micaela S. Parker; Edward A. Laws; Lorraine C. Backer; Lora E. Fleming
2008-01-01
Anthropogenically-derived increases in atmospheric greenhouse gas concentrations have been implicated in recent climate change, and are projected to substantially impact the climate on a global scale in the future. For marine and freshwater systems, increasing concentrations of greenhouse gases are expected to increase surface temperatures, lower pH, and cause changes...
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Conner, William H.; Krauss, Ken W.; Shaffer, Gary P.; Stanturf, John A.; Madsen, Palle; Lamb, David
2012-01-01
Freshwater forested wetlands commonly occur in the lower Coastal Plain of the southeastern US with baldcypress (Taxodium distichum [L.] L.C. Rich.) and water tupelo (Nyssa aquatica L.) often being the dominant trees. Extensive anthropogenic activities combined with eustatic sea-level rise and land subsidence have caused widespread hydrological changes in many of these forests. In addition, hurricanes (a common, although aperiodic occurrence) cause wide-spread damage from wind and storm surge events, with impacts exacerbated by human-mediated coastal modifications (e.g., dredging, navigation channels, etc.). Restoration of forested wetlands in coastal areas is important because emergent canopies can greatly diminish wind penetration, thereby reducing the wind stress available to generate surface waves and storm surge that are the major cause of damage to coastal ecosystems and their surrounding communities. While there is an overall paucity of large-scale restoration efforts within coastal forested wetlands of the southeastern US, we have determined important characteristics that should drive future efforts. Restoration efforts may be enhanced considerably if coupled with hydrological enhancement, such as freshwater, sediment, or sewage wastewater diversions. Large-scale restoration of coastal forests should be attempted to create a landscape capable of minimizing storm impacts and maximizing wetland sustainability in the face of climate change. Planting is the preferred regeneration method in many forested wetland sites because hydrological alterations have increased flooding, and planted seedlings must be protected from herbivory to enhance establishment. Programs identifying salt tolerance in coastal forest tree species need to be continued to help increase resilience to repetitive storm surge events.
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Increased risk of a shutdown of ocean convection posed by warm North Atlantic summers
NASA Astrophysics Data System (ADS)
Oltmanns, Marilena; Karstensen, Johannes; Fischer, Jürgen
2018-04-01
A shutdown of ocean convection in the subpolar North Atlantic, triggered by enhanced melting over Greenland, is regarded as a potential transition point into a fundamentally different climate regime1-3. Noting that a key uncertainty for future convection resides in the relative importance of melting in summer and atmospheric forcing in winter, we investigate the extent to which summer conditions constrain convection with a comprehensive dataset, including hydrographic records that are over a decade in length from the convection regions. We find that warm and fresh summers, characterized by increased sea surface temperatures, freshwater concentrations and melting, are accompanied by reduced heat and buoyancy losses in winter, which entail a longer persistence of the freshwater near the surface and contribute to delaying convection. By shortening the time span for the convective freshwater export, the identified seasonal dynamics introduce a potentially critical threshold that is crossed when substantial amounts of freshwater from one summer are carried over into the next and accumulate. Warm and fresh summers in the Irminger Sea are followed by particularly short convection periods. We estimate that in the winter 2010-2011, after the warmest and freshest Irminger Sea summer on our record, 40% of the surface freshwater was retained.
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Andrew L. Rypel
2009-01-01
The role of climate variability in the ecology of freshwater fishes is of increasing interest. However, there are relatively few tools available for examining how freshwater fish populations respond to climate variations. Here, I apply tree-ring techniques to incremental growth patterns in largemouth bass (Micropterus salmoides Lacepe`de) otoliths to explore...
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In brief: Climate change and water: Perspectives from the Forest Service
USDA Forest Service
2008-01-01
Freshwater availability is an increasing concern across the globe and it may be the most important natural resource issue of the century. Climate change and its effects on water are expected to intensify freshwater scarcity and conflict. A forthcoming Forest Service, U.S. Department of Agriculture report will highlight the importance of managing forests to provide...
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Wendell R. Haag; Melvin L. Warren
1995-01-01
Little is known about the distribution of freshwater mussels in Mississippi national forests. Review of the scant available information revealed that the national forests harbor a diverse mussel fauna of possibly 46 or more species (including confirmed, probable, and potential occurrences). Occurrence of 33 species is confirmed. Because of the geographic, physiographic...
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Filling gaps in a large reserve network to address freshwater conservation needs.
Hermoso, Virgilio; Filipe, Ana Filipa; Segurado, Pedro; Beja, Pedro
2015-09-15
Freshwater ecosystems and biodiversity are among the most threatened at global scale, but efforts for their conservation have been mostly peripheral to terrestrial conservation. For example, Natura 2000, the world's largest network of protected areas, fails to cover adequately the distribution of rare and endangered aquatic species, and lacks of appropriate spatial design to make conservation for freshwater biodiversity effective. Here, we develop a framework to identify a complementary set of priority areas and enhance the conservation opportunities of Natura 2000 for freshwater biodiversity, using the Iberian Peninsula as a case study. We use a systematic planning approach to identify a minimum set of additional areas that would help i) adequately represent all freshwater fish, amphibians and aquatic reptiles at three different target levels, ii) account for key ecological processes derived from riverscape connectivity, and iii) minimize the impact of threats, both within protected areas and propagated from upstream unprotected areas. Addressing all these goals would need an increase in area between 7 and 46%, depending on the conservation target used and strength of connectivity required. These new priority areas correspond to subcatchments inhabited by endangered and range restricted species, as well as additional subcatchments required to improve connectivity among existing protected areas and to increase protection against upstream threats. Our study should help guide future revisions of the design of Natura 2000, while providing a framework to address deficiencies in reserve networks for adequately protecting freshwater biodiversity elsewhere. Copyright © 2015 Elsevier Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Reinfried, S.; Tempelmann, S.; Aeschbacher, U.
2012-02-01
"Water knowledge" has now become a socio-political and future-orientated necessity. Erroneous notions or preconceptions of hydrology can have a deleterious effect on our understanding of the scientific facts and their interrelations that are of relevance to sustainable water management. This explorative pilot study shows that erroneous and naïve ideas about the origin of freshwater springs are common at the lower secondary level. The purpose of this study was two-fold: (1) to investigate the nature of misconceptions about freshwater springs among 13-year-old students, and (2) to develop an efficient instructional tool that promotes conceptual reconstruction in the learners' minds. To assess students' naïve ideas we conducted interviews, examined student work, and asked students to fill in a questionnaire. The identified naïve ideas were used to construct an instructional tool based on the findings of learning psychology aiming at promoting deep learning, thus facilitating a lasting conceptual reconstruction of the concept of freshwater springs.
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Molluscs for Sale: Assessment of Freshwater Gastropods and Bivalves in the Ornamental Pet Trade.
Ng, Ting Hui; Tan, Siong Kiat; Wong, Wing Hing; Meier, Rudolf; Chan, Sow-Yan; Tan, Heok Hui; Yeo, Darren C J
2016-01-01
The ornamental pet trade is often considered a key culprit for conservation problems such as the introduction of invasive species (including infectious diseases) and overharvesting of rare species. Here, we present the first assessment of the biodiversity of freshwater molluscs in the ornamental pet trade in Singapore, one of the most important global hubs of the ornamental aquarium trade, and discuss associated conservation concerns. We recorded freshwater molluscs from ornamental pet shops and major exporters including non-ornamental species (e.g., hitchhikers, molluscs sold as fish feed). We recorded an unexpectedly high diversity-59 species-of freshwater bivalves and gastropods, with the majority (38 species or 64%) being from the Oriental region. In addition to morphological examination, we sequenced the DNA barcode region of mitochondrial CO1 and 16S genes to provide molecular data for the confirmation of the identification and for future re-identification. DNA barcodes were obtained for 50 species, and all but four were separated by > 3% uncorrected pairwise distances. The trade has been considered a main introduction pathway for non-native species to Singapore, and we found that out of 15 species in the trade as well as in the wild in Singapore, 12 are either introduced or of unknown origin, representing almost half of the known non-native freshwater molluscs in Singapore. Particularly prevalent are non-ornamental species: six hitchhikers on aquarium plants and six species sold as fish feed. We found that a quarter of the trade species have a history of introduction, which includes 11 known or potentially invasive species. We conclude that potential overharvesting is difficult to assess because only half of the trade species have been treated by IUCN. Of these, 21 species are of Least Concern and three are Data Deficient. Our checklist, with accompanying DNA barcodes, images, and museum vouchers, provides an important reference library for future monitoring, and constitutes a step toward creating a more sustainable ornamental pet trade.
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Tougas-Tellier, Marie-Andrée; Morin, Jean; Hatin, Daniel; Lavoie, Claude
2015-01-01
Climate change will likely affect flooding regimes, which have a large influence on the functioning of freshwater riparian wetlands. Low water levels predicted for several fluvial systems make wetlands especially vulnerable to the spread of invaders, such as the common reed (Phragmites australis), one of the most invasive species in North America. We developed a model to map the distribution of potential germination grounds of the common reed in freshwater wetlands of the St. Lawrence River (Québec, Canada) under current climate conditions and used this model to predict their future distribution under two climate change scenarios simulated for 2050. We gathered historical and recent (remote sensing) data on the distribution of common reed stands for model calibration and validation purposes, then determined the parameters controlling the species establishment by seed. A two-dimensional model and the identified parameters were used to simulate the current (2010) and future (2050) distribution of germination grounds. Common reed stands are not widespread along the St. Lawrence River (212 ha), but our model suggests that current climate conditions are already conducive to considerable further expansion (>16,000 ha). Climate change may also exacerbate the expansion, particularly if river water levels drop, which will expose large bare areas propitious to seed germination. This phenomenon may be particularly important in one sector of the river, where existing common reed stands could increase their areas by a factor of 100, potentially creating the most extensive reedbed complex in North America. After colonizing salt and brackishwater marshes, the common reed could considerably expand into the freshwater marshes of North America which cover several million hectares. The effects of common reed expansion on biodiversity are difficult to predict, but likely to be highly deleterious given the competitiveness of the invader and the biological richness of freshwater wetlands. PMID:26380675
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Molluscs for Sale: Assessment of Freshwater Gastropods and Bivalves in the Ornamental Pet Trade
Tan, Siong Kiat; Wong, Wing Hing; Meier, Rudolf; Chan, Sow-Yan; Tan, Heok Hui; Yeo, Darren C. J.
2016-01-01
The ornamental pet trade is often considered a key culprit for conservation problems such as the introduction of invasive species (including infectious diseases) and overharvesting of rare species. Here, we present the first assessment of the biodiversity of freshwater molluscs in the ornamental pet trade in Singapore, one of the most important global hubs of the ornamental aquarium trade, and discuss associated conservation concerns. We recorded freshwater molluscs from ornamental pet shops and major exporters including non-ornamental species (e.g., hitchhikers, molluscs sold as fish feed). We recorded an unexpectedly high diversity—59 species—of freshwater bivalves and gastropods, with the majority (38 species or 64%) being from the Oriental region. In addition to morphological examination, we sequenced the DNA barcode region of mitochondrial CO1 and 16S genes to provide molecular data for the confirmation of the identification and for future re-identification. DNA barcodes were obtained for 50 species, and all but four were separated by > 3% uncorrected pairwise distances. The trade has been considered a main introduction pathway for non-native species to Singapore, and we found that out of 15 species in the trade as well as in the wild in Singapore, 12 are either introduced or of unknown origin, representing almost half of the known non-native freshwater molluscs in Singapore. Particularly prevalent are non-ornamental species: six hitchhikers on aquarium plants and six species sold as fish feed. We found that a quarter of the trade species have a history of introduction, which includes 11 known or potentially invasive species. We conclude that potential overharvesting is difficult to assess because only half of the trade species have been treated by IUCN. Of these, 21 species are of Least Concern and three are Data Deficient. Our checklist, with accompanying DNA barcodes, images, and museum vouchers, provides an important reference library for future monitoring, and constitutes a step toward creating a more sustainable ornamental pet trade. PMID:27525660
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Modeling water resources as a constraint in electricity capacity expansion models
NASA Astrophysics Data System (ADS)
Newmark, R. L.; Macknick, J.; Cohen, S.; Tidwell, V. C.; Woldeyesus, T.; Martinez, A.
2013-12-01
In the United States, the electric power sector is the largest withdrawer of freshwater in the nation. The primary demand for water from the electricity sector is for thermoelectric power plant cooling. Areas likely to see the largest near-term growth in population and energy usage, the Southwest and the Southeast, are also facing freshwater scarcity and have experienced water-related power reliability issues in the past decade. Lack of water may become a barrier for new conventionally-cooled power plants, and alternative cooling systems will impact technology cost and performance. Although water is integral to electricity generation, it has long been neglected as a constraint in future electricity system projections. Assessing the impact of water resource scarcity on energy infrastructure development is critical, both for conventional and renewable energy technologies. Efficiently utilizing all water types, including wastewater and brackish sources, or utilizing dry-cooling technologies, will be essential for transitioning to a low-carbon electricity system. This work provides the first demonstration of a national electric system capacity expansion model that incorporates water resources as a constraint on the current and future U.S. electricity system. The Regional Electricity Deployment System (ReEDS) model was enhanced to represent multiple cooling technology types and limited water resource availability in its optimization of electricity sector capacity expansion to 2050. The ReEDS model has high geographic and temporal resolution, making it a suitable model for incorporating water resources, which are inherently seasonal and watershed-specific. Cooling system technologies were assigned varying costs (capital, operations and maintenance), and performance parameters, reflecting inherent tradeoffs in water impacts and operating characteristics. Water rights supply curves were developed for each of the power balancing regions in ReEDS. Supply curves include costs and availability of freshwater (surface and groundwater) and alternative water resources (municipal wastewater and brackish groundwater). In each region, a new power plant must secure sufficient water rights for operation before being built. Water rights constraints thus influence the type of power plant, cooling system, or location of new generating capacity. Results indicate that the aggregate national generating capacity by fuel type and associated carbon dioxide emissions change marginally with the inclusion of water rights. Water resource withdrawals and consumption, however, can vary considerably. Regional water resource dynamics indicate substantial differences in the location where power plant-cooling system technology combinations are built. These localized impacts highlight the importance of considering water resources as a constraint in the electricity sector when evaluating costs, transmission infrastructure needs, and externalities. Further scenario evaluations include assessments of how climate change could affect the availability of water resources, and thus the development of the electricity sector.
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Besser, John M.; Brumbaugh, William G.; Kemble, Nile E.; Ivey, Chris D.; Kunz, James L.; Ingersoll, Christopher G.; Rudel, David
2011-01-01
This report summarizes data from studies of the toxicity and bioavailability of nickel in nickel-spiked freshwater sediments. The goal of these studies was to generate toxicity and chemistry data to support development of broadly applicable sediment quality guidelines for nickel. The studies were conducted as three tasks, which are presented here as three chapters: Task 1, Development of methods for preparation and toxicity testing of nickel-spiked freshwater sediments; Task 2, Sensitivity of benthic invertebrates to toxicity of nickel-spiked freshwater sediments; and Task 3, Effect of sediment characteristics on nickel bioavailability. Appendices with additional methodological details and raw chemistry and toxicity data for the three tasks are available online at http://pubs.usgs.gov/sir/2011/5225/downloads/.
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A physically based model of global freshwater surface temperature
NASA Astrophysics Data System (ADS)
Beek, Ludovicus P. H.; Eikelboom, Tessa; Vliet, Michelle T. H.; Bierkens, Marc F. P.
2012-09-01
Temperature determines a range of physical properties of water and exerts a strong control on surface water biogeochemistry. Thus, in freshwater ecosystems the thermal regime directly affects the geographical distribution of aquatic species through their growth and metabolism and indirectly through their tolerance to parasites and diseases. Models used to predict surface water temperature range between physically based deterministic models and statistical approaches. Here we present the initial results of a physically based deterministic model of global freshwater surface temperature. The model adds a surface water energy balance to river discharge modeled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff, and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by shortwave and longwave radiation and sensible and latent heat fluxes. Also included are ice formation and its effect on heat storage and river hydraulics. We use the coupled surface water and energy balance model to simulate global freshwater surface temperature at daily time steps with a spatial resolution of 0.5° on a regular grid for the period 1976-2000. We opt to parameterize the model with globally available data and apply it without calibration in order to preserve its physical basis with the outlook of evaluating the effects of atmospheric warming on freshwater surface temperature. We validate our simulation results with daily temperature data from rivers and lakes (U.S. Geological Survey (USGS), limited to the USA) and compare mean monthly temperatures with those recorded in the Global Environment Monitoring System (GEMS) data set. Results show that the model is able to capture the mean monthly surface temperature for the majority of the GEMS stations, while the interannual variability as derived from the USGS and NOAA data was captured reasonably well. Results are poorest for the Arctic rivers because the timing of ice breakup is predicted too late in the year due to the lack of including a mechanical breakup mechanism. Moreover, surface water temperatures for tropical rivers were overestimated, most likely due to an overestimation of rainfall temperature and incoming shortwave radiation. The spatiotemporal variation of water temperature reveals large temperature differences between water and atmosphere for the higher latitudes, while considerable lateral transport of heat can be observed for rivers crossing hydroclimatic zones, such as the Nile, the Mississippi, and the large rivers flowing to the Arctic. Overall, our model results show promise for future projection of global surface freshwater temperature under global change.
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Large-scale degradation of Amazonian freshwater ecosystems
NASA Astrophysics Data System (ADS)
Castello, L.; Macedo, M.
2016-12-01
The integrity of freshwater ecosystems depends on their hydrological connectivity with land, water, and climate systems. Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. However, the hydrological connectivity of Amazonian freshwater ecosystems is increasingly disrupted by construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation; evaluates their impacts on hydrological connectivity; and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 155 large hydroelectric dams in operation, 21 dams under construction, and there will be only three free-flowing tributaries if all 277 planned dams for the Basin are built. Land-cover changes driven by mining, dam and road construction, and agriculture and cattle ranching have already affected 20% of the Basin and up to 50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g. droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and do not consider the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basin-wide research and policy framework to understand and manage hydrological connectivity across multiple spatial scales and jurisdictional boundaries.
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Simulating Freshwater Availability under Future Climate Conditions
NASA Astrophysics Data System (ADS)
Zhao, F.; Zeng, N.; Motesharrei, S.; Gustafson, K. C.; Rivas, J.; Miralles-Wilhelm, F.; Kalnay, E.
2013-12-01
Freshwater availability is a key factor for regional development. Precipitation, evaporation, river inflow and outflow are the major terms in the estimate of regional water supply. In this study, we aim to obtain a realistic estimate for these variables from 1901 to 2100. First we calculated the ensemble mean precipitation using the 2011-2100 RCP4.5 output (re-sampled to half-degree spatial resolution) from 16 General Circulation Models (GCMs) participating the Coupled Model Intercomparison Project Phase 5 (CMIP5). The projections are then combined with the half-degree 1901-2010 Climate Research Unit (CRU) TS3.2 dataset after bias correction. We then used the combined data to drive our UMD Earth System Model (ESM), in order to generate evaporation and runoff. We also developed a River-Routing Scheme based on the idea of Taikan Oki, as part of the ESM. It is capable of calculating river inflow and outflow for any region, driven by the gridded runoff output. River direction and slope information from Global Dominant River Tracing (DRT) dataset are included in our scheme. The effects of reservoirs/dams are parameterized based on a few simple factors such as soil moisture, population density and geographic regions. Simulated river flow is validated with river gauge measurements for the world's major rivers. We have applied our river flow calculation to two data-rich watersheds in the United States: Phoenix AMA watershed and the Potomac River Basin. The results are used in our SImple WAter model (SIWA) to explore water management options.
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Skovrind, Mikkel; Olsen, Morten Tange; Vieira, Filipe Garrett; Pacheco, George; Carl, Henrik; Gilbert, M Thomas P; Møller, Peter Rask
2016-02-01
Climate change experts largely agree that future climate change and associated rises in oceanic water levels over the upcoming decades, will affect marine salinity levels. The subsequent effects on fish communities in estuarine ecosystems however, are less clear. One species that is likely to become increasingly affected by changes in salinity is the ide (Leuciscus idus). The ide is a stenohaline freshwater fish that primarily inhabits rivers, with frequent anadromous behavior when sea salinity does not exceed 15%. Unlike most other anadromous Baltic Sea fish species, the ide has yet to be subjected to large-scale stocking programs, and thus provides an excellent opportunity for studying the natural population structure across the current salinity gradient in the Danish Belts. To explore this, we used Genotyping-by-Sequencing to determine genomic population structure of both freshwater resident and anadromous ide populations in the western Baltic Sea region, and relate the results to the current salinity gradient and the demographic history of ide in the region. The sample sites separate into four clusters, with all anadromous populations in one cluster and the freshwater resident populations in the remaining three. Results demonstrate high level of differentiation between sites hosting freshwater resident populations, but little differentiation among anadromous populations. Thus ide exhibit the genomic population structure of both a typical freshwater species, and a typical anadromous species. In addition to providing a first insight into the population structure of north-western European ide, our data also (1) provide indications of a single illegal introduction by man; (2) suggest limited genetic effects of heavy pollution in the past; and (3) indicate possible historical anadromous behavior in a now isolated freshwater population.
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Eerkes-Medrano, Dafne; Thompson, Richard C; Aldridge, David C
2015-05-15
Plastic contamination is an increasing environmental problem in marine systems where it has spread globally to even the most remote habitats. Plastic pieces in smaller size scales, microplastics (particles <5 mm), have reached high densities (e.g., 100,000 items per m(3)) in waters and sediments, and are interacting with organisms and the environment in a variety of ways. Early investigations of freshwater systems suggest microplastic presence and interactions are equally as far reaching as are being observed in marine systems. Microplastics are being detected in freshwaters of Europe, North America, and Asia, and the first organismal studies are finding that freshwater fauna across a range of feeding guilds ingest microplastics. Drawing from the marine literature and these initial freshwater studies, we review the issue of microplastics in freshwater systems to summarise current understanding, identify knowledge gaps and suggest future research priorities. Evidence suggests that freshwater systems may share similarities to marine systems in the types of forces that transport microplastics (e.g. surface currents); the prevalence of microplastics (e.g. numerically abundant and ubiquitous); the approaches used for detection, identification and quantification (e.g. density separation, filtration, sieving and infrared spectroscopy); and the potential impacts (e.g. physical damage to organisms that ingest them, chemical transfer of toxicants). Differences between freshwater and marine systems include the closer proximity to point sources in freshwaters, the typically smaller sizes of freshwater systems, and spatial and temporal differences in the mixing/transport of particles by physical forces. These differences between marine and freshwater systems may lead to differences in the type of microplastics present. For example, rivers may show a predictable pattern in microplastic characteristics (size, shape, relative abundance) based on waste sources (e.g. household vs. industrial) adjacent to the river, and distance downstream from a point source. Given that the study of microplastics in freshwaters has only arisen in the last few years, we are still limited in our understanding of 1) their presence and distribution in the environment; 2) their transport pathways and factors that affect distributions; 3) methods for their accurate detection and quantification; 4) the extent and relevance of their impacts on aquatic life. We also do not know how microplastics might transfer from freshwater to terrestrial ecosystems, and we do not know if and how they may affect human health. This is concerning because human populations have a high dependency on freshwaters for drinking water and for food resources. Increasing the level of understanding in these areas is essential if we are to develop appropriate policy and management tools to address this emerging issue. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Heijerick, D G; Regoli, L; Carey, S
2012-10-01
The REACH Molybdenum Consortium initiated an extensive research program in order to generate robust PNECs, based on the SSD approach, for both the freshwater and marine environments. This activity was part of the REACH dossier preparation and to form the basis for scientific dialogues with other national and international regulatory authorities. Chronic ecotoxicity data sets for the freshwater and marine environments served as starting point for the derivation of PNECs for both compartments, in accordance with the recommended derivation procedures established by the European Chemicals Agency (ECHA). The HC(5,50%)s that were derived from the generated Species Sensitivity Distributions were 38.2 mg Mo/L and 5.75 mg Mo/L for the freshwater and marine water compartment, respectively. Uncertainty analysis on both data sets and available data on bioaccumulation at high exposure levels justified an assessment factor of 3 on both HC(5,50%) leading to a PNEC(freshwater) of 12.7 mg Mo/L and a PNEC(marine) of 1.92 mg Mo/L. As there are currently insufficient ecotoxicological data available for the derivation of PNECs in the sediment compartment, the equilibrium partitioning method was applied; typical K(D)-values for both the freshwater and marine compartments were identified and combined with the respective PNEC, leading to a PNEC(sediment) of 22,600 mg/kg dry weight and 1980 mg/kg dry weight for freshwater and marine sediments, respectively. The chronic data sets were also used for the derivation of final chronic values using the procedures that are outlined by the US Environmental Protection Agency for deriving such water benchmarks. Comparing PNECs with FCVs showed that both methodologies result in comparable protective concentration levels for molybdenum in the environment. Copyright © 2012 Elsevier B.V. All rights reserved.
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Pandit, Shubha N; Maitland, Bryan M; Pandit, Laxmi K; Poesch, Mark S; Enders, Eva C
2017-11-15
Climate change is affecting many freshwater species, particularly fishes. Predictions of future climate change suggest large and deleterious effects on species with narrow dispersal abilities due to limited hydrological connectivity. In turn, this creates the potential for population isolation in thermally unsuitable habitats, leading to physiological stress, species declines or possible extirpation. The current extent of many freshwater fish species' spatio-temporal distribution patterns and their sensitivity to thermal impacts from climate change - critical information for conservation planning - are often unknown. Carmine shiner (Notropis percobromus) is an ecologically important species listed as threatened or imperilled nationally (Canada) and regionally (South Dakota, United States) due to its restricted range and sensitivity to water quality and temperature. This research aimed to determine the current distribution and spatio-temporal variability in projected suitable habitat for Carmine shiner using niche-based modeling approaches (MaxEnt, BIOCLIM, and DOMAIN models). Statistically downscaled, bias-corrected Global Circulation Models (GCMs) data was used to model the distribution of Carmine shiner in central North America for the period of 2041-2060 (2050s). Maximum mean July temperature and temperature variability were the main factors in determining Carmine shiner distribution. Patterns of projected habitat change by the 2050s suggest the spatial extent of the current distribution of Carmine shiner would shift north, with >50% of the current distribution changing with future projections based on two Representative Concentrations Pathways for CO 2 emissions. Whereas the southern extent of the distribution would become unsuitable for Carmine shiner, suitable habitats are predicted to become available further north, if accessible. Importantly, the majority of habitat gains for Carmine shiner would be in areas currently inaccessible due to dispersal limitations, suggesting current populations may face an extinction debt within the next half century. These results provide evidence that Carmine shiner may be highly vulnerable to a warming climate and suggest that management actions - such as assisted migration - may be needed to mitigate impacts from climate change and ensure the long-term persistence of the species. Copyright © 2017 Elsevier B.V. All rights reserved.
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Interbasin water transfer, riverine connectivity, and spatial controls on fish biodiversity
Grant, Evan H. Campbell; Lynch, Heather J.; Muneepeerakul, Rachata; Muthukumarasamy, Arunachalam; Rodríguez-Iturbe, Ignacio; Fagan, William F.
2012-01-01
Background Large-scale inter-basin water transfer (IBWT) projects are commonly proposed as solutions to water distribution and supply problems. These problems are likely to intensify under future population growth and climate change scenarios. Scarce data on the distribution of freshwater fishes frequently limits the ability to assess the potential implications of an IBWT project on freshwater fish communities. Because connectivity in habitat networks is expected to be critical to species' biogeography, consideration of changes in the relative isolation of riverine networks may provide a strategy for controlling impacts of IBWTs on freshwater fish communities Methods/Principal Findings Using empirical data on the current patterns of freshwater fish biodiversity for rivers of peninsular India, we show here how the spatial changes alone under an archetypal IBWT project will (1) reduce freshwater fish biodiversity system-wide, (2) alter patterns of local species richness, (3) expand distributions of widespread species throughout peninsular rivers, and (4) decrease community richness by increasing inter-basin similarity (a mechanism for the observed decrease in biodiversity). Given the complexity of the IBWT, many paths to partial or full completion of the project are possible. We evaluate two strategies for step-wise implementation of the 11 canals, based on economic or ecological considerations. We find that for each step in the project, the impacts on freshwater fish communities are sensitive to which canal is added to the network. Conclusions/Significance Importantly, ecological impacts can be reduced by associating the sequence in which canals are added to characteristics of the links, except for the case when all 11 canals are implemented simultaneously (at which point the sequence of canal addition is inconsequential). By identifying the fundamental relationship between the geometry of riverine networks and freshwater fish biodiversity, our results will aid in assessing impacts of IBWT projects and balancing ecosystem and societal demands for freshwater, even in cases where biodiversity data are limited.
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Interbasin Water Transfer, Riverine Connectivity, and Spatial Controls on Fish Biodiversity
Grant, Evan H. Campbell; Lynch, Heather J.; Muneepeerakul, Rachata; Arunachalam, Muthukumarasamy; Rodríguez-Iturbe, Ignacio; Fagan, William F.
2012-01-01
Background Large-scale inter-basin water transfer (IBWT) projects are commonly proposed as solutions to water distribution and supply problems. These problems are likely to intensify under future population growth and climate change scenarios. Scarce data on the distribution of freshwater fishes frequently limits the ability to assess the potential implications of an IBWT project on freshwater fish communities. Because connectivity in habitat networks is expected to be critical to species' biogeography, consideration of changes in the relative isolation of riverine networks may provide a strategy for controlling impacts of IBWTs on freshwater fish communities. Methods/Principal Findings Using empirical data on the current patterns of freshwater fish biodiversity for rivers of peninsular India, we show here how the spatial changes alone under an archetypal IBWT project will (1) reduce freshwater fish biodiversity system-wide, (2) alter patterns of local species richness, (3) expand distributions of widespread species throughout peninsular rivers, and (4) decrease community richness by increasing inter-basin similarity (a mechanism for the observed decrease in biodiversity). Given the complexity of the IBWT, many paths to partial or full completion of the project are possible. We evaluate two strategies for step-wise implementation of the 11 canals, based on economic or ecological considerations. We find that for each step in the project, the impacts on freshwater fish communities are sensitive to which canal is added to the network. Conclusions/Significance Importantly, ecological impacts can be reduced by associating the sequence in which canals are added to characteristics of the links, except for the case when all 11 canals are implemented simultaneously (at which point the sequence of canal addition is inconsequential). By identifying the fundamental relationship between the geometry of riverine networks and freshwater fish biodiversity, our results will aid in assessing impacts of IBWT projects and balancing ecosystem and societal demands for freshwater, even in cases where biodiversity data are limited. PMID:22470533
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Interbasin water transfer, riverine connectivity, and spatial controls on fish biodiversity.
Grant, Evan H Campbell; Lynch, Heather J; Muneepeerakul, Rachata; Arunachalam, Muthukumarasamy; Rodríguez-Iturbe, Ignacio; Fagan, William F
2012-01-01
Large-scale inter-basin water transfer (IBWT) projects are commonly proposed as solutions to water distribution and supply problems. These problems are likely to intensify under future population growth and climate change scenarios. Scarce data on the distribution of freshwater fishes frequently limits the ability to assess the potential implications of an IBWT project on freshwater fish communities. Because connectivity in habitat networks is expected to be critical to species' biogeography, consideration of changes in the relative isolation of riverine networks may provide a strategy for controlling impacts of IBWTs on freshwater fish communities. Using empirical data on the current patterns of freshwater fish biodiversity for rivers of peninsular India, we show here how the spatial changes alone under an archetypal IBWT project will (1) reduce freshwater fish biodiversity system-wide, (2) alter patterns of local species richness, (3) expand distributions of widespread species throughout peninsular rivers, and (4) decrease community richness by increasing inter-basin similarity (a mechanism for the observed decrease in biodiversity). Given the complexity of the IBWT, many paths to partial or full completion of the project are possible. We evaluate two strategies for step-wise implementation of the 11 canals, based on economic or ecological considerations. We find that for each step in the project, the impacts on freshwater fish communities are sensitive to which canal is added to the network. Importantly, ecological impacts can be reduced by associating the sequence in which canals are added to characteristics of the links, except for the case when all 11 canals are implemented simultaneously (at which point the sequence of canal addition is inconsequential). By identifying the fundamental relationship between the geometry of riverine networks and freshwater fish biodiversity, our results will aid in assessing impacts of IBWT projects and balancing ecosystem and societal demands for freshwater, even in cases where biodiversity data are limited.
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Liu, Wen-Cheng; Chan, Wen-Ting
2015-12-01
Climate change is one of the key factors affecting the future microbiological water quality in rivers and tidal estuaries. A coupled 3D hydrodynamic and fecal coliform transport model was developed and applied to the Danshuei River estuarine system for predicting the influences of climate change on microbiological water quality. The hydrodynamic and fecal coliform model was validated using observational salinity and fecal coliform distributions. According to the analyses of the statistical error, predictions of the salinity and the fecal coliform concentration from the model simulation quantitatively agreed with the observed data. The validated model was then applied to predict the fecal coliform contamination as a result of climate change, including the change of freshwater discharge and the sea level rise. We found that the reduction of freshwater discharge under climate change scenarios resulted in an increase in the fecal coliform concentration. The sea level rise would decrease fecal coliform distributions because both the water level and the water volume increased. A reduction in freshwater discharge has a negative impact on the fecal coliform concentration, whereas a rising sea level has a positive influence on the fecal coliform contamination. An appropriate strategy for the effective microbiological management in tidal estuaries is required to reveal the persistent trends of climate in the future.
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NASA Astrophysics Data System (ADS)
Krusche, A. V.; Ballester, M. V.; Neill, C.; Elsenbeer, H.; Johnson, M. S.; Coe, M. T.; Garavello, M.; Molina, S. G.; Empinotti, V.; Reichardt, F.; Deegan, L.; Harris, L.
2014-12-01
The main goal of this project is to identify how impacts from land conversion, cropland expansion and intensification of both crop and animal production interact to affect regional evapotranspiration, rainfall generation, river flooding, and water quality and stream habitats, allowing us to identify thresholds of change that will endanger agricultural production, livelihoods of non-agricultural settlers and the region's new urban population and infrastructure. We will survey the effects of this on (1) soybean farmers, (2) cattle ranchers, (3) small-scale farm families, (4) rural non-agriculturists, including fishers, and (5) urban residents and map their roles as stakeholders. We will also conduct current water use surveys among the different stakeholder groups, accompanied by questions on desired aspects for future freshwater security to identify targets for desirable outcomes of water governance strategies. These targets, together with the information on land use drivers, water quantity and quality and predicted scenarios for global changes will be incorporated into a fully integrated and interactive geospatially oriented socio-ecological model that can serve as framework for future water governance that enhances Freshwater Security in such systems. This is an international cooperation initiative lead by Brazil and with the participation of Canada, Germany and United States of America.
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Sectoral contributions to surface water stress in the coterminous United States
K. Averyt; J. Meldrum; P. Caldwell; G. Sun; S. McNulty; A. Huber-Lee; N. Madden
2013-01-01
Here, we assess current stress in the freshwater system based on the best available data in order to understand possible risks and vulnerabilities to regional water resources and the sectors dependent on freshwater. We present watershed-scale measures of surface water supply stress for the coterminous United States (US) using the water supply stress index (WaSSI) model...
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Growth and longevity in freshwater mussels: evolutionary and conservation implications
Wendell R. Haag; Andrew L. Rypel
2010-01-01
The amount of energy allocated to growth versus other functions is a fundamental feature of an organismâs life history. Constraints on energy availability result in characteristic trade-offs among life-history traits and reflect strategies by which organisms adapt to their environments. Freshwater mussels are a diverse and imperiled component of aquatic ecosystems but...
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Tuning fresh: radiation through rewiring of central metabolism in streamlined bacteria
Eiler, Alexander; Mondav, Rhiannon; Sinclair, Lucas; ...
2016-01-19
Most free-living planktonic cells are streamlined and in spite of their limitations in functional flexibility, their vast populations have radiated into a wide range of aquatic habitats. Here we compared the metabolic potential of subgroups in the Alphaproteobacteria lineage SAR11 adapted to marine and freshwater habitats. Our results suggest that the successful leap from marine to freshwaters in SAR11 was accompanied by a loss of several carbon degradation pathways and a rewiring of the central metabolism. Examples for these are C1 and methylated compounds degradation pathways, the Entner-Doudouroff pathway, the glyoxylate shunt and anapleuretic carbon fixation being absent from themore » freshwater genomes. Evolutionary reconstruc tions further suggest that the metabolic modules making up these important freshwater metabolic traits were already present in the gene pool of ancestral marine SAR11 populations. The loss of the glyoxylate shunt had already occurred in the common ancestor of the freshwater subgroup and its closest marine relatives, suggesting that the adaptation to freshwater was a gradual process. Furthermore, our results indicate rapid evolution of TRAP transporters in the freshwater clade involved in the uptake of low molecular weight carboxylic acids. We propose that such gradual tuning of metabolic pathways and transporters toward locally available organic substrates is linked to the formation of subgroups within the SAR11 clade and that this process was critical for the freshwater clade to find and fix an adaptive phenotype.« less
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Groschen, George E.
1994-01-01
Results of the projected withdrawal simulations from 1984-2000 indicate that the general historical trend of saline-water movement probably will continue. The saline water in the Rio Grande alluvium is the major source of saline-water intrusion into the freshwater zone throughout the historical period and into the future on the basis of simulation results. Some saline water probably will continue to move downward from the Rio Grande alluvium to the freshwater below. Injection of treated sewage effluent into some wells will create a small zone of freshwater containing slightly increased amounts of dissolved solids in the northern area of the Texas part of the Hueco bolson aquifer. Many factors, such as well interference, pumping schedules, and other factors not specifically represented in the regional simulation, can substantially affect dissolved-solids concentrations at individual wells.
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Freshwater biodiversity and aquatic insect diversification.
Dijkstra, Klaas-Douwe B; Monaghan, Michael T; Pauls, Steffen U
2014-01-01
Inland waters cover less than 1% of Earth's surface but harbor more than 6% of all insect species: Nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Little is known about how this remarkable diversity arose, although allopatric speciation and ecological adaptation are thought to be primary mechanisms. Freshwater habitats are highly susceptible to environmental change and exhibit marked ecological gradients. Standing waters appear to harbor more dispersive species than running waters, but there is little understanding of how this fundamental ecological difference has affected diversification. In contrast to the lack of evolutionary studies, the ecology and habitat preferences of aquatic insects have been intensively studied, in part because of their widespread use as bioindicators. The combination of phylogenetics with the extensive ecological data provides a promising avenue for future research, making aquatic insects highly suitable models for the study of ecological diversification.
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Freshwater Biodiversity and Insect Diversification
Dijkstra, Klaas-Douwe B.; Monaghan, Michael T.; Pauls, Steffen U.
2016-01-01
Inland waters cover less than one percent of Earth’s surface, but harbor more than six percent of all insect species: nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Little is known about how this remarkable diversity arose, although allopatric speciation and ecological adaptation are thought to be primary mechanisms. Freshwater habitats are exceptionally susceptible to environmental change, and exhibit marked ecological gradients. The amphibiotic lifestyles of aquatic insects result in complex contributions of extinction and allopatric and non-allopatric speciation in species diversification. In contrast to the lack of evolutionary studies, the ecology and habitat preferences of aquatic insects have been intensively studied, in part because of their widespread use as bio-indicators. The combination of phylogenetics with the extensive ecological data provides a promising avenue for future research, making aquatic insects highly suitable models for the study of ecological diversification. PMID:24160433
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Sensitivity ranking for freshwater invertebrates towards hydrocarbon contaminants.
Gerner, Nadine V; Cailleaud, Kevin; Bassères, Anne; Liess, Matthias; Beketov, Mikhail A
2017-11-01
Hydrocarbons have an utmost economical importance but may also cause substantial ecological impacts due to accidents or inadequate transportation and use. Currently, freshwater biomonitoring methods lack an indicator that can unequivocally reflect the impacts caused by hydrocarbons while being independent from effects of other stressors. The aim of the present study was to develop a sensitivity ranking for freshwater invertebrates towards hydrocarbon contaminants, which can be used in hydrocarbon-specific bioindicators. We employed the Relative Sensitivity method and developed the sensitivity ranking S hydrocarbons based on literature ecotoxicological data supplemented with rapid and mesocosm test results. A first validation of the sensitivity ranking based on an earlier field study has been conducted and revealed the S hydrocarbons ranking to be promising for application in sensitivity based indicators. Thus, the first results indicate that the ranking can serve as the core component of future hydrocarbon-specific and sensitivity trait based bioindicators.
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Wu, Jui-Pin; Chen, Hon-Cheng; Li, Mei-Hui
2012-08-01
Although toxic responses of freshwater planarians after exposure to environmental toxicants can be observed through external toxicological end points, physiological responses inside the bodies of treated planarians have rarely been investigated. The present study was designed, using cadmium (Cd) as a reference toxicant, to determine its bioaccumulation and toxicodynamics in the freshwater planarian, Dugesia japonica, after acute toxicity was obtained. Accumulated Cd concentrations, metallothionein levels, and the oxidative status in planarians were determined after exposure to Cd. Furthermore, we hypothesized that the acute death of Cd-treated planarians was associated with increased oxidative stress. After Cd-treated planarians were coexposed to antioxidant, N-acetylcysteine (NAC), we found that NAC protected planarians from Cd lethality by maintaining the oxidative status and decreasing the bioaccumulation of Cd. The results of the present study support planarians being used as a practical model for toxicological studies of environmental contaminants in the future.
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Melo, Bruno F.; Benine, Ricardo C.; Britzke, Ricardo; Gama, Cecile S.; Oliveira, Claudio
2016-01-01
Abstract The Amazon Basin occupies a vast portion of northern South America and contains some of the highest species richness in the world. The northern Brazilian state of Amapá is delimited by the Amazonas River to the south, the Oyapock River to the northern boundary with French Guyana, and the Atlantic northeastern coast to Amazon estuary. Despite several expeditions to the Amazon in recent decades, little is known about the freshwater ichthyofauna from Amapá, with records limited to local inventories and species descriptions. This paper presents a compilation of the freshwater fish diversity sampled in fifteen sites covering two major Amapá ecoregions during the dry season of 2015. 120 species representing eight orders and 40 families are reported upon in this work. Eight species appear for the first time in the Brazilian territory providing new information for future conservation status evaluations. PMID:27551225
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Assessing and managing freshwater ecosystems vulnerable to global change
Angeler, David G.; Allen, Craig R.; Birge, Hannah E.; Drakare, Stina; McKie, Brendan G.; Johnson, Richard K.
2014-01-01
Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change.
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Seasonal cycle of the mixed-layer heat and freshwater budget in the eastern tropical Atlantic
NASA Astrophysics Data System (ADS)
Rath, Willi; Dengler, Marcus; Lüdke, Jan; Schmidtko, Sunke; Schlundt, Michael; Brandt, Peter; Partners, Preface
2016-04-01
A new seasonal mixed-layer heat flux climatology is used to explore the mechanisms driving seasonal variability of sea surface temperature and salinity in the eastern tropical Atlantic (ETA) with a focus on the eastern boundary upwelling regions. Until recently, large areas at the continental margins of the ETA were not well covered by publically available hydrographic data hampering a detailed understanding of the involved processes. In a collaborative effort between African and European partners within the EU-funded PREFACE program, a new seasonal climatology for different components of the heat and freshwater budget was compiled for the ETA using all publically available hydrographic data sets and a large trove of previously not-publically available hydrographic measurements from the territorial waters of western African countries, either from national programs or from the FAO supported EAF-Nansen program. The publically available data includes hydrographic data from global data repositories including most recent ARGO floats and glider measurements. This data set was complemented by velocity data from surface drifter and ARGO floats to allow determining horizontal heat and freshwater advection. Monthly means of air-sea heat fluxes were derived from the TropFlux climatology while precipitation rates were derived from monthly mean fields of the Global Precipitation Climatology Project. Finally, microstructure data from individual measurement campaigns allow estimating diapycnal heat and salt fluxes for certain regions during specific months. A detailed analysis of the seasonal cycle of mixed-layer heat and freshwater balance in previously poorly covered regions in the eastern tropical Atlantic upwelling is presented. In both eastern boundary upwelling region, off Senegal/Mauritania and off Angola/Namibia, average net surface heat fluxes warm the mixed layer at a rate between 50 and 80 W/m2 with maxima in the respective summer seasons. Horizontal advection contributed to cooling of the mixed layer but a residual cooling term remains in both upwelling regions. A surprising result is that this residual is largest in the Angolan upwelling region, where upwelling-favourable winds are generally weaker than off Namibia and in the north-eastern upwelling region. The contributions of windstress-derived vertical advection and diapycnal heat and freshwater fluxes are discussed. In addition, the TropFlux climatology is evaluated against radiative and turbulent ocean-atmosphere heat and freshwater fluxes derived from ship-board observations.
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Pietsch, Renée B; Vinatzer, Boris A; Schmale, David G
2017-01-01
The bacterium Pseudomonas syringae is found in a variety of terrestrial and aquatic environments. Some strains of P. syringae express an ice nucleation protein (hereafter referred to as Ice+) allowing them to catalyze the heterogeneous freezing of water. Though P. syringae has been sampled intensively from freshwater sources in France, little is known about the genetic diversity of P. syringae in natural aquatic habitats in North America. We collected samples of freshwater from three different depths in Claytor Lake, Virginia, USA between November 2015 and June 2016. Samples were plated on non-selective medium (TSA) and on medium selective for Pseudomonas (KBC) and closely related species to estimate the total number of culturable bacteria and of Pseudomonas , respectively. A droplet freezing assay was used to screen colonies for the Ice+ phenotype. Ice+ colonies were then molecularly identified based on the cts (citrate synthase) gene and the 16S rDNA gene. Phylogenetic analysis of cts sequences showed a surprising diversity of phylogenetic subgroups of P. syringae . Frequencies of Ice+ isolates on P. syringae selective medium ranged from 0 to 15% per sample with the highest frequency being found in spring. Our work shows that freshwater lakes can be a significant reservoir of Ice+ P. syringae . Future work is needed to determine the contribution of P. syringae from freshwater lakes to the P. syringae populations present in the atmosphere and on plants and, in particular, if freshwater lakes could be an inoculum source of P. syringae -caused plant disease outbreaks.
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Sources, variability and fate of freshwater in the Bellingshausen Sea, Antarctica
NASA Astrophysics Data System (ADS)
Regan, Heather C.; Holland, Paul R.; Meredith, Michael P.; Pike, Jennifer
2018-03-01
During the second half of the twentieth century, the Antarctic Peninsula was subjected to a rapid increase in air temperatures. This was accompanied by a reduction in sea ice extent, increased precipitation and a dramatic retreat of glaciers associated with an increase in heat flux from deep ocean water masses. Isotopic tracers have been used previously to investigate the relative importance of the different freshwater sources to the adjacent Bellingshausen Sea (BS), but the data coverage is strongly biased toward summer. Here we use a regional model to investigate the ocean's response to the observed changes in its different freshwater inputs (sea ice melt/freeze, precipitation, evaporation, iceberg/glacier melt, and ice shelf melt). The model successfully recreates BS water masses and performs well against available freshwater data. By tracing the sources and pathways of the individual components of the freshwater budget, we find that sea ice dominates seasonal changes in the total freshwater content and flux, but all sources make a comparable contribution to the annual-mean. Interannual variability is dominated by sea ice and precipitation. Decadal trends in the salinity and stratification of the ocean are investigated, and a 20-year surface freshening from 1992 to 2011 is found to be predominantly driven by decreasing autumn sea ice growth. These findings will help to elucidate the role of freshwater in driving circulation and water column structure changes in this climatically-sensitive region.
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NASA Astrophysics Data System (ADS)
Kitagawa, Takashi; Aoki, Yoshinori
2017-03-01
When discussing the evolution of fish migration, it is necessary to consider the total benefit fish acquire over their entire life history. With diadromous migration, for instance, some fish species migrate from freshwater and feed in the ocean (anadromous species), and others migrate from the ocean and feed in freshwater (catadromous). These contrasting directions of migration can largely be explained by the relative availability of food resources in ocean and freshwater habitats [1]. However, there are few examples that measure or quantify total energy as a concrete value that a single fish acquires through migration.
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NASA Astrophysics Data System (ADS)
Yun, Jin-Ho
Extensive efforts have been made to evaluate the potential of microalgae as a biofuel feedstock during the past 4-5 decades. However, filamentous freshwater macroalgae have numerous characteristics that favor their potential use as an alternative algal feedstock for biofuels production. Freshwater macroalgae exhibit high rates of areal productivity, and their tendency to form dense floating mats on the water surface imply significant reductions in harvesting and dewater costs compared to microalgae. In Chapter 1, I reviewed the published literature on the elemental composition and energy content of five genera of freshwater macroalgae. This review suggested that freshwater macroalgae compare favorably with traditional bio-based energy sources, including terrestrial residues, wood, and coal. In addition, I performed a semi-continuous culture experiment using the common Chlorophyte genus Oedogonium to investigate whether nutrient availability can influence its higher heating value (HHV), productivity, and proximate analysis. The experimental study suggested that the most nutrient-limited growth conditions resulted in a significant increase in the HHV of the Oedogonium biomass (14.4 MJ/kg to 16.1 MJ/kg). Although there was no significant difference in productivity between the treatments, the average dry weight productivity of Oedogonium (3.37 g/m2/day) was found to be much higher than is achievable with common terrestrial plant crops. Although filamentous freshwater macroalgae, therefore, have significant potential as a renewable source of bioenergy, the ultimate success of freshwater macroalgae as a biofuel feedstock will depend upon the ability to produce biomass at the commercial-scale in a cost-effective and sustainable manner. Aquatic ecology can play an important role to achieve the scale-up of algal crop production by informing the supply rates of nutrients to the cultivation systems, and by helping to create adaptive production systems that are resilient to environmental change. In Chapter 2, I performed a review and an analysis of data from the published literature on the large-cultivation of freshwater macroalgae. This study revealed that the large-scale cultivation of freshwater macroalgae is feasible at relatively low cost using currently available technologies such as the Algal Turf Scrubber system (ATS). In addition, graphical analyses of published data obtained from ATS systems of varying sizes in operation worldwide revealed that both macroalgal biomass productivity and nutrient removal rates are hyperbolically related to the areal loading rates of both total nitrogen and total phosphorus. An assessment of the limited existing literature on carbon dioxide amendments suggested that the effectiveness and need for CO2 supplementation of macroalgal production systems like the ATS has not yet been conclusively demonstrated. Overall, this thesis demonstrates that filamentous freshwater macroalgae have great potential as a feedstock for both liquid and solid fuels, especially if nutrient-rich wastewater can be used as the supply of water and mineral nutrients. In addition, this thesis highlights the importance of studying the algal cultivation conditions that influence trade-offs between nutrient loading, biomass productivity, and biomass energy content. In particular, the hyperbolic relationship between algal biomass productivity and the areal loading rates of both total nitrogen and total phosphorus should provide critical insight when considering the production costs of macroalgal biomass at the commercial-scale.
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Emerging trends in global freshwater availability.
Rodell, M; Famiglietti, J S; Wiese, D N; Reager, J T; Beaudoing, H K; Landerer, F W; Lo, M-H
2018-05-01
Freshwater availability is changing worldwide. Here we quantify 34 trends in terrestrial water storage observed by the Gravity Recovery and Climate Experiment (GRACE) satellites during 2002-2016 and categorize their drivers as natural interannual variability, unsustainable groundwater consumption, climate change or combinations thereof. Several of these trends had been lacking thorough investigation and attribution, including massive changes in northwestern China and the Okavango Delta. Others are consistent with climate model predictions. This observation-based assessment of how the world's water landscape is responding to human impacts and climate variations provides a blueprint for evaluating and predicting emerging threats to water and food security.
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Nematodes from terrestrial and freshwater habitats in the Arctic
2014-01-01
Abstract We present an updated list of terrestrial and freshwater nematodes from all regions of the Arctic, for which records of properly identified nematode species are available: Svalbard, Jan Mayen, Iceland, Greenland, Nunavut, Northwest territories, Alaska, Lena River estuary, Taymyr and Severnaya Zemlya and Novaya Zemlya. The list includes 391 species belonging to 146 genera, 54 families and 10 orders of the phylum Nematoda. PMID:25197239
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Will water scarcity in semiarid regions limit hydraulic fracturing of shale plays?
NASA Astrophysics Data System (ADS)
Scanlon, Bridget R.; Reedy, Robert C.; Nicot, Jean Philippe
2014-12-01
There is increasing concern about water constraints limiting oil and gas production using hydraulic fracturing (HF) in shale plays, particularly in semiarid regions and during droughts. Here we evaluate HF vulnerability by comparing HF water demand with supply in the semiarid Texas Eagle Ford play, the largest shale oil producer globally. Current HF water demand (18 billion gallons, bgal; 68 billion liters, bL in 2013) equates to ˜16% of total water consumption in the play area. Projected HF water demand of ˜330 bgal with ˜62 000 additional wells over the next 20 years equates to ˜10% of historic groundwater depletion from regional irrigation. Estimated potential freshwater supplies include ˜1000 bgal over 20 yr from recharge and ˜10 000 bgal from aquifer storage, with land-owner lease agreements often stipulating purchase of freshwater. However, pumpage has resulted in excessive drawdown locally with estimated declines of ˜100-200 ft in ˜6% of the western play area since HF began in 2009-2013. Non-freshwater sources include initial flowback water, which is ≤5% of HF water demand, limiting reuse/recycling. Operators report shifting to brackish groundwater with estimated groundwater storage of 80 000 bgal. Comparison with other semiarid plays indicates increasing brackish groundwater and produced water use in the Permian Basin and large surface water inputs from the Missouri River in the Bakken play. The variety of water sources in semiarid regions, with projected HF water demand representing ˜3% of fresh and ˜1% of brackish water storage in the Eagle Ford footprint indicates that, with appropriate management, water availability should not physically limit future shale energy production.
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A Blue/Green Water-based Accounting Framework for Assessment of Water Security
NASA Astrophysics Data System (ADS)
Rodrigues, D. B.; Gupta, H. V.; Mendiondo, E. M.
2013-12-01
A comprehensive assessment of water security can incorporate several water-related concepts, including provisioning and support for freshwater ecosystem services, water footprint, water scarcity, and water vulnerability, while accounting for Blue and Green Water (BW and GW) flows defined in accordance with the hydrological processes involved. Here, we demonstrate how a quantitative analysis of provisioning and demand (in terms of water footprint) for BW and GW ecosystem services can be conducted, so as to provide indicators of water scarcity and vulnerability at the basin level. To illustrate the approach, we use the Soil and Water Assessment Tool (SWAT) to model the hydrology of an agricultural basin (291 sq.km) within the Cantareira water supply system in Brazil. To provide a more comprehensive basis for decision-making, we compute the BW provision using three different hydrological-based methods for specifying monthly Environmental Flow Requirements (EFRs) for 23 year-period. The current BW-Footprint was defined using surface water rights for reference year 2012. Then we analyzed the BW- and GW-Footprints against long-term series of monthly values of freshwater availability. Our results reveal clear spatial and temporal patterns of water scarcity and vulnerability levels within the basin, and help to distinguish between human and natural reasons (drought) for conditions of insecurity. The Blue/Green water-based accounting framework developed here can be benchmarked at a range of spatial scales, thereby improving our understanding of how and where water-related threats to human and aquatic ecosystem security can arise. Future investigation will be necessary to better understand the intra-annual variability of blue water demand and to evaluate the impacts of uncertainties associated with a) the water rights database, b) the effects of climate change projections on blue and green freshwater provision.
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Crowe, S J; Newton, A E; Gould, L H; Parsons, M B; Stroika, S; Bopp, C A; Freeman, M; Greene, K; Mahon, B E
2016-11-01
Toxigenic strains of Vibrio cholerae serogroups O1 and O139 have caused cholera epidemics, but other serogroups - such as O75 or O141 - can also produce cholera toxin and cause severe watery diarrhoea similar to cholera. We describe 31 years of surveillance for toxigenic non-O1, non-O139 infections in the United States and map these infections to the state where the exposure probably originated. While serogroups O75 and O141 are closely related pathogens, they differ in how and where they infect people. Oysters were the main vehicle for O75 infection. The vehicles for O141 infection include oysters, clams, and freshwater in lakes and rivers. The patients infected with serogroup O75 who had food traceback information available ate raw oysters from Florida. Patients infected with O141 ate oysters from Florida and clams from New Jersey, and those who only reported being exposed to freshwater were exposed in Arizona, Michigan, Missouri, and Texas. Improving the safety of oysters, specifically, should help prevent future illnesses from these toxigenic strains and similar pathogenic Vibrio species. Post-harvest processing of raw oysters, such as individual quick freezing, heat-cool pasteurization, and high hydrostatic pressurization, should be considered.
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Wongsawad, Chalobol; Wongsawad, Pheravut; Sukontason, Kom; Maneepitaksanti, Worawit; Nantarat, Nattawadee
2017-02-01
This study aimed to investigate the morphology and reconstruct the phylogenetic relationships of Centrocestus formosanus originating from 5 species of freshwater fish, i.e., Esomus metallicus, Puntius brevis, Anabas testudineus, Parambassis siamensis , and Carassius auratus , in Chiang Mai province, Thailand. Sequence-related amplified polymorphism (SRAP) and phylogeny based on internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (CO1) were performed. The results showed similar morphologies of adult C. formosanus from day 5 after infection in chicks. C. formosanus originated from 4 species of freshwater fish had the same number of circumoral spines on the oral sucker, except for those from C. auratus which revealed 34 circumoral spines. The phylogenetic tree obtained from SRAP profile and the combination of ITS2 and CO1 sequence showed similar results that were correlated with the number of circumoral spines in adult worms. Genetic variability of C. formosanus also occurred in different species of freshwater fish hosts. However, more details of adult worm morphologies and more sensitive genetic markers are needed to confirm the species validity of C. formosanus with 34 circumoral spines originating from C. auratus in the future.
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Wongsawad, Chalobol; Wongsawad, Pheravut; Sukontason, Kom; Maneepitaksanti, Worawit; Nantarat, Nattawadee
2017-01-01
This study aimed to investigate the morphology and reconstruct the phylogenetic relationships of Centrocestus formosanus originating from 5 species of freshwater fish, i.e., Esomus metallicus, Puntius brevis, Anabas testudineus, Parambassis siamensis, and Carassius auratus, in Chiang Mai province, Thailand. Sequence-related amplified polymorphism (SRAP) and phylogeny based on internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (CO1) were performed. The results showed similar morphologies of adult C. formosanus from day 5 after infection in chicks. C. formosanus originated from 4 species of freshwater fish had the same number of circumoral spines on the oral sucker, except for those from C. auratus which revealed 34 circumoral spines. The phylogenetic tree obtained from SRAP profile and the combination of ITS2 and CO1 sequence showed similar results that were correlated with the number of circumoral spines in adult worms. Genetic variability of C. formosanus also occurred in different species of freshwater fish hosts. However, more details of adult worm morphologies and more sensitive genetic markers are needed to confirm the species validity of C. formosanus with 34 circumoral spines originating from C. auratus in the future. PMID:28285504
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Ground-Water Availability in the Wailuku Area, Maui, Hawai'i
Gingerich, Stephen B.
2008-01-01
Most of the public water supply in Maui, Hawai'i, is from a freshwater lens in the Wailuku area of the island. Because of population growth, ground-water withdrawals from wells in this area increased from less than 10 Mgal/d during 1970 to about 23 Mgal/d during 2006. In response to increased withdrawals from the freshwater lens in the Wailuku area, water levels declined, the transition zone between freshwater and saltwater became shallower, and the chloride concentrations of water pumped from wells increased. These responses led to concern over the long-term sustainability of withdrawals from existing and proposed wells. A three-dimensional numerical ground-water flow and transport model was developed to simulate the effects of selected withdrawal and recharge scenarios on water levels, on the transition zone between freshwater and saltwater, and on surface-water/ground-water interactions. The model was constructed using time-varying recharge, withdrawals, and ocean levels. Hydraulic characteristics used to construct the model were initially based on published estimates but ultimately were varied to obtain better agreement between simulated and measured water levels and salinity profiles in the modeled area during the period 1926-2006. Scenarios included ground-water withdrawal at 2006 and 1996 rates and locations with average recharge (based on 2000-04 land use and 1926-2004 rainfall) and withdrawal at redistributed rates and locations with several different recharge scenarios. Simulation results indicate that continuing 1996 and 2006 withdrawal distributions into the future results in decreased water levels, a thinner freshwater lens, increased salinity from pumped wells, and higher salinity at several current withdrawal sites. A redistributed withdrawal condition in which ground-water withdrawal was redistributed to maximize withdrawal and minimize salinities in the withdrawn water was determined. The redistributed withdrawal simulates 27.1 Mgal/d of withdrawal from 14 wells or well fields in the Wailuku area. Simulation results from the five scenarios that include redistributed withdrawal conditions indicate the following for the Wailuku Aquifer Sector: (1) withdrawal during times of average recharge rates cause average water levels to decrease 2-3 ft and the transition zone to become more than 200 ft shallower after 150 years; (2) a 5-yr drought condition similar to the 1998-2002 drought results in additional salinity increases after 30 years (12.5 years of normal recharge after drought conditions) but only one well has salinity increases of concern; (3) additional recharge from restored streamflow significantly increases water levels, thickens the freshwater body, and decreases salinity at withdrawal sites in the Waihe'e and 'Iao Aquifer Systems; and (4) a complete removal of irrigation recharge decreases water levels and increases salinity in the central isthmus where irrigation is reduced, but recharge through restored streams still significantly increases water levels, thickens the freshwater body, and decreases salinity at withdrawal sites in the Waihe'e and 'Iao Aquifer Systems.
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Essaid, Hedeff I.
1990-01-01
A quasi three-dimensional, finite difference model, that simulates freshwater and saltwater flow separated by a sharp interface, has been developed to study layered coastal aquifer systems. The model allows for regional simulation of coastal groundwater conditions, including the effects of saltwater dynamics on the freshwater system. Vertically integrated freshwater and saltwater flow equations incorporating the interface boundary condition are solved within each aquifer. Leakage through confining layers is calculated by Darcy's law, accounting for density differences across the layer. The locations of the interface tip and toe, within grid blocks, are tracked by linearly extrapolating the position of the interface. The model has been verified using available analytical solutions and experimental results. Application of the model to the Soquel-Aptos basin, Santa Cruz County, California, illustrates the use of the quasi three-dimensional, sharp interface approach for the examination of freshwater-saltwater dynamics in regional systems. Simulation suggests that the interface, today, is still responding to long-term Pleistocene sea level fluctuations and has not achieved equilibrium with present day sea level conditions.
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Iijima, Hiroko; Nakaya, Yuka; Kuwahara, Ayuko; Hirai, Masami Yokota; Osanai, Takashi
2015-01-01
Water use assessment is important for bioproduction using cyanobacteria. For eco-friendly reasons, seawater should preferably be used for cyanobacteria cultivation instead of freshwater. In this study, we demonstrated that the freshwater unicellular cyanobacterium Synechocystis sp. PCC 6803 could be grown in a medium based on seawater. The Synechocystis wild-type strain grew well in an artificial seawater (ASW) medium supplemented with nitrogen and phosphorus sources. The addition of HEPES buffer improved cell growth overall, although the growth in ASW medium was inferior to that in the synthetic BG-11 medium. The levels of proteins involved in sugar metabolism changed depending on the culture conditions. The biosynthesis of several amino acids including aspartate, glutamine, glycine, proline, ornithine, and lysine, was highly up-regulated by cultivation in ASW. Two types of natural seawater (NSW) were also made available for the cultivation of Synechocystis cells, with supplementation of both nitrogen and phosphorus sources. These results revealed the potential use of seawater for the cultivation of freshwater cyanobacteria, which would help to reduce freshwater consumption during biorefinery using cyanobacteria. PMID:25954257
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Terekhanova, Nadezhda V.; Logacheva, Maria D.; Penin, Aleksey A.; Neretina, Tatiana V.; Barmintseva, Anna E.; Bazykin, Georgii A.; Kondrashov, Alexey S.; Mugue, Nikolai S.
2014-01-01
Adaptation is driven by natural selection; however, many adaptations are caused by weak selection acting over large timescales, complicating its study. Therefore, it is rarely possible to study selection comprehensively in natural environments. The threespine stickleback (Gasterosteus aculeatus) is a well-studied model organism with a short generation time, small genome size, and many genetic and genomic tools available. Within this originally marine species, populations have recurrently adapted to freshwater all over its range. This evolution involved extensive parallelism: pre-existing alleles that adapt sticklebacks to freshwater habitats, but are also present at low frequencies in marine populations, have been recruited repeatedly. While a number of genomic regions responsible for this adaptation have been identified, the details of selection remain poorly understood. Using whole-genome resequencing, we compare pooled genomic samples from marine and freshwater populations of the White Sea basin, and identify 19 short genomic regions that are highly divergent between them, including three known inversions. 17 of these regions overlap protein-coding genes, including a number of genes with predicted functions that are relevant for adaptation to the freshwater environment. We then analyze four additional independently derived young freshwater populations of known ages, two natural and two artificially established, and use the observed shifts of allelic frequencies to estimate the strength of positive selection. Adaptation turns out to be quite rapid, indicating strong selection acting simultaneously at multiple regions of the genome, with selection coefficients of up to 0.27. High divergence between marine and freshwater genotypes, lack of reduction in polymorphism in regions responsible for adaptation, and high frequencies of freshwater alleles observed even in young freshwater populations are all consistent with rapid assembly of G. aculeatus freshwater genotypes from pre-existing genomic regions of adaptive variation, with strong selection that favors this assembly acting simultaneously at multiple loci. PMID:25299485
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Terekhanova, Nadezhda V; Logacheva, Maria D; Penin, Aleksey A; Neretina, Tatiana V; Barmintseva, Anna E; Bazykin, Georgii A; Kondrashov, Alexey S; Mugue, Nikolai S
2014-10-01
Adaptation is driven by natural selection; however, many adaptations are caused by weak selection acting over large timescales, complicating its study. Therefore, it is rarely possible to study selection comprehensively in natural environments. The threespine stickleback (Gasterosteus aculeatus) is a well-studied model organism with a short generation time, small genome size, and many genetic and genomic tools available. Within this originally marine species, populations have recurrently adapted to freshwater all over its range. This evolution involved extensive parallelism: pre-existing alleles that adapt sticklebacks to freshwater habitats, but are also present at low frequencies in marine populations, have been recruited repeatedly. While a number of genomic regions responsible for this adaptation have been identified, the details of selection remain poorly understood. Using whole-genome resequencing, we compare pooled genomic samples from marine and freshwater populations of the White Sea basin, and identify 19 short genomic regions that are highly divergent between them, including three known inversions. 17 of these regions overlap protein-coding genes, including a number of genes with predicted functions that are relevant for adaptation to the freshwater environment. We then analyze four additional independently derived young freshwater populations of known ages, two natural and two artificially established, and use the observed shifts of allelic frequencies to estimate the strength of positive selection. Adaptation turns out to be quite rapid, indicating strong selection acting simultaneously at multiple regions of the genome, with selection coefficients of up to 0.27. High divergence between marine and freshwater genotypes, lack of reduction in polymorphism in regions responsible for adaptation, and high frequencies of freshwater alleles observed even in young freshwater populations are all consistent with rapid assembly of G. aculeatus freshwater genotypes from pre-existing genomic regions of adaptive variation, with strong selection that favors this assembly acting simultaneously at multiple loci.
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Gómez, Fernando; Moreira, David; López-García, Purificación
2010-01-01
The dinoflagellate genus Ceratium contains marine and freshwater species. Freshwater species possess six cingular plates, thick plates in the concave ventral area and usually develop a third hypothecal horn. The marine Ceratium species (>62 species) possess five cingular plates and thin plates in the concave ventral area; a third hypothecal horn is atypical. Resting cysts, a common feature in the freshwater species, are unreported in marine species. We illustrate for the first time resting cysts in marine Ceratium species (C. furca and C. candelabrum). We obtained small subunit ribosomal RNA gene (SSU rDNA) sequences of 23 Ceratium species (more than one third of the total marine species described so far), with representatives of the four acknowledged subgenera. Phylogenetic analyses including the type species, the freshwater C. hirundinella, showed that the four available sequences of freshwater species formed a strongly supported subclade, very distant from the marine cluster. Our data support the splitting of Ceratium sensu lato into two genera. Ceratium sensu stricto should be reserved for freshwater species possessing six cingular plates (three cingular plates in dorsal view). The new genus name, Neoceratium gen. nov. should be applied to the marine species of Ceratium sensu lato that possess five cingular plates (two cingular plates in dorsal view). Copyright 2009 Elsevier GmbH. All rights reserved.
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Logue, Jürg Brendan; Langenheder, Silke; Andersson, Anders F; Bertilsson, Stefan; Drakare, Stina; Lanzén, Anders; Lindström, Eva S
2012-01-01
A central goal in ecology is to grasp the mechanisms that underlie and maintain biodiversity and patterns in its spatial distribution can provide clues about those mechanisms. Here, we investigated what might determine the bacterioplankton richness (BR) in lakes by means of 454 pyrosequencing of the 16S rRNA gene. We further provide a BR estimate based upon a sampling depth and accuracy, which, to our knowledge, are unsurpassed for freshwater bacterioplankton communities. Our examination of 22 669 sequences per lake showed that freshwater BR in fourteen nutrient-poor lakes was positively influenced by nutrient availability. Our study is, thus, consistent with the finding that the supply of available nutrients is a major driver of species richness; a pattern that may well be universally valid to the world of both micro- and macro-organisms. We, furthermore, observed that BR increased with elevated landscape position, most likely as a consequence of differences in nutrient availability. Finally, BR decreased with increasing lake and catchment area that is negative species–area relationships (SARs) were recorded; a finding that re-opens the debate about whether positive SARs can indeed be found in the microbial world and whether positive SARs can in fact be pronounced as one of the few ‘laws' in ecology. PMID:22170419
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State Water Resource Competition and the Resulting Consequences of Diminished Water Supply
2014-10-01
world . Because this realization is becoming more and more prevalent, the human survival instinct is prompting competition and conflict over water...the main contributing factors in creating a more interdependent world when it comes to freshwater. Freshwater availability has diminished over time...climate change, appears to be changing the landscape of our world for the worse. Along with a new landscape comes new demand for resource
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Horn, M.A.
2000-01-01
Techniques for management of drainage basins that use water budgets to balance available water resources with actual or anticipated water use require accurate and precise estimates of basin withdrawals, interbasin transfers of freshwater, unaccounted-for use, water use, consumptive use, inflow and infiltration, basin return flow, and interbasin transfers of wastewater. Frequently, interbasin transfers of freshwater and wastewater are not included in basin water budgets because they occur within public water-delivery and wastewater-collection systems. A new 10-step method was developed to improve estimates of inflow and infiltration and interbasin transfers using readily available statewide data. The accuracy and precision of water-use estimates determined by this method are improved through careful application of coefficients for small users and the use of metered values for large users. The method was developed and tested with data for the Ten Mile River Basin in southeastern Massachusetts. This report uses examples from the basin to illustrate each step of the method.
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Extensive collections of histopathology materials from studies of marine and freshwater mollusks, crustaceans, echinoderms, and other organisms are archived in the Registry of Tumors in Lower Animals (RTLA), the U.S. Environmental Protection Agency, NOAA’s National Marine Fisheri...
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Extensive collections of histopathology materials from studies of marine and freshwater mollusks, crustaceans, echinoderms, and other organisms are archived in the Registry of Tumors in Lower Animals (RTLA), the U.S. Environmental Protection Agency, NOAA’s National Marine Fishe...
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Treasures in Archived Histolopathology Collections: Preserving the Past for Future Understanding
Extensive collections of histopathology materials from studies of marine and freshwater mollusks, crustaceans, echinoderms, and other organisms are archived in the Registry of Tumors in Lower Animals (RTLA), the U.S. Environmental Protection Agency, NOAA’s National Marine Fishe...
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Bucak, Tuba; Trolle, Dennis; Tavşanoğlu, Ü Nihan; Çakıroğlu, A İdil; Özen, Arda; Jeppesen, Erik; Beklioğlu, Meryem
2018-04-15
Climate change and intense land use practices are the main threats to ecosystem structure and services of Mediterranean lakes. Therefore, it is essential to predict the future changes and develop mitigation measures to combat such pressures. In this study, Lake Beyşehir, the largest freshwater lake in the Mediterranean basin, was selected to study the impacts of climate change and various land use scenarios on the ecosystem dynamics of Mediterranean freshwater ecosystems and the services that they provide. For this purpose, we linked catchment model outputs to the two different processed-based lake models: PCLake and GLM-AED, and tested the scenarios of five General Circulation Models, two Representation Concentration Pathways and three different land use scenarios, which enable us to consider the various sources of uncertainty. Climate change and land use scenarios generally predicted strong future decreases in hydraulic and nutrient loads from the catchment to the lake. These changes in loads translated into alterations in water level as well as minor changes in chlorophyll a (Chl-a) concentrations. We also observed an increased abundance of cyanobacteria in both lake models. Total phosphorus, temperature and hydraulic loading were found to be the most important variables determining cyanobacteria biomass. As the future scenarios revealed only minor changes in Chl-a due to the significant decrease in nutrient loads, our results highlight that reduced nutrient loading in a warming world may play a crucial role in offsetting the effects of temperature on phytoplankton growth. However, our results also showed increased abundance of cyanobacteria in the future may threaten ecosystem integrity and may limit drinking water ecosystem services. In addition, extended periods of decreased hydraulic loads from the catchment and increased evaporation may lead to water level reductions and may diminish the ecosystem services of the lake as a water supply for irrigation and drinking water. Copyright © 2017 Elsevier B.V. All rights reserved.
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Martínez, Aingeru; Kominoski, John Stephen; Larrañaga, Aitor
2017-12-01
Climate change is increasing overall temporal variability in precipitation resulting in a seasonal water availability, both increasing periods of flooding and water scarcity. During low water availability periods, the concentration of leachates from riparian vegetation increases, subsequently increasing dissolved organic matter (DOM). Moreover, shifts in riparian vegetation by land use changes impact the quantity and quality of DOM. Our objective was to test effects of increasing DOM concentrations from Eucalyptus grandis (one of the most cultivated tree species in the world) leachates on the metabolism (respiration, R; gross primary productivity, GPP) and extracellular enzyme activities (EEAs) of freshwater biofilms. To test effects of DOM concentrations on freshwater biofilm functions, we incubated commercial cellulose sponges in a freshwater pond to allow biofilm colonization, and then exposed biofilms to five different concentrations of leaf-litter leachates of E. grandis for five days. To test if responses to DOM concentrations varied with colonization stage of biofilms, we measured treatment effects on biofilms colonizing standard substrates after one, two, three and four weeks of colonization. Increases in leachates concentrations enhanced biofilm heterotrophy, increasing R rates and decreasing GPP. Leachate concentrations did not affect biofilm EEAs, and changes in biofilm metabolism were not explained by treatment-induced changes in biofilm biomass or stoichiometry. We detected the lowest production:respiration ratios, i.e. more heterotrophic assemblages, with the most concentrated leachate solution and the most advanced biofilm colonization stages. Shifts in quantity of dissolved organic matter in freshwaters may further influence ecosystem metabolism and carbon processing. Copyright © 2017 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Wada, Y.; Flörke, M.; Hanasaki, N.; Eisner, S.; Fischer, G.; Tramberend, S.; Satoh, Y.; van Vliet, M. T. H.; Yillia, P.; Ringler, C.; Burek, P.; Wiberg, D.
2016-01-01
To sustain growing food demand and increasing standard of living, global water use increased by nearly 6 times during the last 100 years, and continues to grow. As water demands get closer and closer to the water availability in many regions, each drop of water becomes increasingly valuable and water must be managed more efficiently and intensively. However, soaring water use worsens water scarcity conditions already prevalent in semi-arid and arid regions, increasing uncertainty for sustainable food production and economic development. Planning for future development and investments requires that we prepare water projections for the future. However, estimations are complicated because the future of the world's waters will be influenced by a combination of environmental, social, economic, and political factors, and there is only limited knowledge and data available about freshwater resources and how they are being used. The Water Futures and Solutions (WFaS) initiative coordinates its work with other ongoing scenario efforts for the sake of establishing a consistent set of new global water scenarios based on the shared socio-economic pathways (SSPs) and the representative concentration pathways (RCPs). The WFaS "fast-track" assessment uses three global water models, namely H08, PCR-GLOBWB, and WaterGAP. This study assesses the state of the art for estimating and projecting water use regionally and globally in a consistent manner. It provides an overview of different approaches, the uncertainty, strengths and weaknesses of the various estimation methods, types of management and policy decisions for which the current estimation methods are useful. We also discuss additional information most needed to be able to improve water use estimates and be able to assess a greater range of management options across the water-energy-climate nexus.
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NASA Technical Reports Server (NTRS)
Wada, Y.; Florke, M.; Hanasaki, N.; Eisner, S.; Fischer, G.; Tramberend, S.; Satoh, Y.; van Vliet, M. T. H.; Yillia, P.; Ringler, C.;
2016-01-01
To sustain growing food demand and increasing standard of living, global water use increased by nearly 6 times during the last 100 years, and continues to grow. As water demands get closer and closer to the water availability in many regions, each drop of water becomes increasingly valuable and water must be managed more efficiently and intensively. However, soaring water use worsens water scarcity conditions already prevalent in semi-arid and arid regions, increasing uncertainty for sustainable food production and economic development. Planning for future development and investments requires that we prepare water projections for the future. However, estimations are complicated because the future of the world's waters will be influenced by a combination of environmental, social, economic, and political factors, and there is only limited knowledge and data available about freshwater resources and how they are being used. The Water Futures and Solutions (WFaS) initiative coordinates its work with other ongoing scenario efforts for the sake of establishing a consistent set of new global water scenarios based on the shared socio-economic pathways (SSPs) and the representative concentration pathways (RCPs). The WFaS "fast track" assessment uses three global water models, namely H08, PCR-GLOBWB, and WaterGAP. This study assesses the state of the art for estimating and projecting water use regionally and globally in a consistent manner. It provides an overview of different approaches, the uncertainty, strengths and weaknesses of the various estimation methods, types of management and policy decisions for which the current estimation methods are useful. We also discuss additional information most needed to be able to improve water use estimates and be able to assess a greater range of management options across the water-energy-climate nexus.
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NASA Astrophysics Data System (ADS)
Wada, Y.; Flörke, M.; Hanasaki, N.; Eisner, S.; Fischer, G.; Tramberend, S.; Satoh, Y.; van Vliet, M. T. H.; Yillia, P.; Ringler, C.; Wiberg, D.
2015-08-01
To sustain growing food demand and increasing standard of living, global water use increased by nearly 6 times during the last 100 years and continues to grow. As water demands get closer and closer to the water availability in many regions, each drop of water becomes increasingly valuable and water must be managed more efficiently and intensively. However, soaring water use worsens water scarcity condition already prevalent in semi-arid and arid regions, increasing uncertainty for sustainable food production and economic development. Planning for future development and investments requires that we prepare water projections for the future. However, estimations are complicated because the future of world's waters will be influenced by a combination of environmental, social, economic, and political factors, and there is only limited knowledge and data available about freshwater resources and how they are being used. The Water Futures and Solutions initiative (WFaS) coordinates its work with other on-going scenario efforts for the sake of establishing a consistent set of new global water scenarios based on the Shared Socioeconomic Pathways (SSPs) and the Representative Concentration Pathways (RCPs). The WFaS "fast-track" assessment uses three global water models, namely H08, PCR-GLOBWB, and WaterGAP. This study assesses the state of the art for estimating and projecting water use regionally and globally in a consistent manner. It provides an overview of different approaches, the uncertainty, strengths and weaknesses of the various estimation methods, types of management and policy decisions for which the current estimation methods are useful. We also discuss additional information most needed to be able to improve water use estimates and be able to assess a greater range of management options across the water-energy-climate nexus.
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NASA Astrophysics Data System (ADS)
Liu, Yonggang; Hallberg, Robert; Sergienko, Olga; Samuels, Bonnie L.; Harrison, Matthew; Oppenheimer, Michael
2017-11-01
Greenland Ice Sheet (GIS) might have lost a large amount of its volume during the last interglacial and may do so again in the future due to climate warming. In this study, we test whether the climate response to the glacial meltwater is sensitive to its discharging location. Two fully coupled atmosphere-ocean general circulation models, CM2G and CM2M, which have completely different ocean components are employed to do the test. In each experiment, a prescribed freshwater flux of 0.1 Sv is discharged from one of the four locations around Greenland—Petermann, 79 North, Jacobshavn and Helheim glaciers. The results from both models show that the AMOC weakens more when the freshwater is discharged from the northern GIS (Petermann and 79 North) than when it is discharged from the southern GIS (Jacobshavn and Helheim), by 15% (CM2G) and 31% (CM2M) averaged over model year 50-300 (CM2G) and 70-300 (CM2M), respectively. This is due to easier access of the freshwater from northern GIS to the deepwater formation site in the Nordic Seas. In the long term (> 300 year), however, the AMOC change is nearly the same for freshwater discharged from any location of the GIS. The East Greenland current accelerates with time and eventually becomes significantly faster when the freshwater is discharged from the north than from the south. Therefore, freshwater from the north is transported efficiently towards the south first and then circulates back to the Nordic Seas, making its impact to the deepwater formation there similar to the freshwater discharged from the south. The results indicate that the details of the location of meltwater discharge matter if the short-term (< 300 years) climate response is concerned, but may not be critical if the long-term (> 300 years) climate response is focused upon.
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Atoll groundwater movement and its response to climatic and sea-level fluctuations
Oberle, Ferdinand; Swarzenski, Peter W.; Storlazzi, Curt
2017-01-01
Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall Islands. As part of a 16-month study, a rarely recorded island-overwash event occurred and the island’s aquifer’s response was measured. The findings suggest that small-scale overwash events cause an increase in salinity of the freshwater lens that returns to pre-overwash conditions within one month. The overwash event is addressed in the context of climate-related local sea-level change, which suggests that overwash events and associated degradations in freshwater resources are likely to increase in severity in the future due to projected rises in sea level. Other forcings, such as severe rainfall events, were shown to have caused a sudden freshening of the aquifer, with salinity levels retuning to pre-rainfall levels within three months. Tidal forcing of the freshwater lens was observed in electrical resistivity profiles, high-resolution conductivity, groundwater-level well measurements and through submarine groundwater discharge calculations. Depth-specific geochemical pore water measurements further assessed and confirmed the distinct boundaries between fresh and saline water masses in the aquifer. The identification of the freshwater lens’ saline boundaries is essential for a quantitative evaluation of the aquifers freshwater resources and help understand how these resources may be impacted by climate change and anthropogenic activities.
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Freshwater savings from marine protein consumption
NASA Astrophysics Data System (ADS)
Gephart, Jessica A.; Pace, Michael L.; D'Odorico, Paolo
2014-01-01
Marine fisheries provide an essential source of protein for many people around the world. Unlike alternative terrestrial sources of protein, marine fish production requires little to no freshwater inputs. Consuming marine fish protein instead of terrestrial protein therefore represents freshwater savings (equivalent to an avoided water cost) and contributes to a low water footprint diet. These water savings are realized by the producers of alternative protein sources, rather than the consumers of marine protein. This study quantifies freshwater savings from marine fish consumption around the world by estimating the water footprint of replacing marine fish with terrestrial protein based on current consumption patterns. An estimated 7 600 km3 yr-1 of water is used for human food production. Replacing marine protein with terrestrial protein would require an additional 350 km3 yr-1 of water, meaning that marine protein provides current water savings of 4.6%. The importance of these freshwater savings is highly uneven around the globe, with savings ranging from as little as 0 to as much as 50%. The largest savings as a per cent of current water footprints occur in Asia, Oceania, and several coastal African nations. The greatest national water savings from marine fish protein occur in Southeast Asia and the United States. As the human population increases, future water savings from marine fish consumption will be increasingly important to food and water security and depend on sustainable harvest of capture fisheries and low water footprint growth of marine aquaculture.
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Large-scale degradation of Amazonian freshwater ecosystems.
Castello, Leandro; Macedo, Marcia N
2016-03-01
Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. This connectivity is increasingly being disrupted by the construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation, evaluates their impacts on hydrological connectivity, and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 154 large hydroelectric dams in operation today, and 21 dams under construction. The current trajectory of dam construction will leave only three free-flowing tributaries in the next few decades if all 277 planned dams are completed. Land-cover changes driven by mining, dam and road construction, agriculture and cattle ranching have already affected ~20% of the Basin and up to ~50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g., droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems, both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and overlook the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basinwide research and policy framework to understand and manage hydrological connectivity across multiple spatial scales and jurisdictional boundaries. © 2015 John Wiley & Sons Ltd.
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Biology: Survival of the finfish
NASA Astrophysics Data System (ADS)
Sunday, Jennifer
2017-10-01
A trait-based approach for assessing physiological sensitivity to climate change can connect a species' evolutionary past with its future vulnerability. Now a global assessment of freshwater and marine fishes reveals patterns of warming sensitivity, highlighting the importance of different biogeographies and identifying places where vulnerability runs high.
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Extensive collections of histopathology materials from studies of marine and freshwater fish, mollusks, crustaceans, echinoderms, and other organisms are archived at the Registry of Tumors in Lower Animals (RTLA), the U.S. Environmental Protection Agency (EPA), NOAA’s National Ma...
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Extensive collections of histopathology materials from studies of marine and freshwater fish, mollusks, crustaceans, echinoderms, and other organisms are archived in the Registry of Tumors in Lower Animals (RTLA), the U.S. Environmental Protection Agency, NOAA’s National Marine F...
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Extensive collections of histopathology materials from studies of marine and freshwater fish, mollusks, crustaceans, echinoderms, and other organisms are archived in the Registry of Tumors in Lower Animals (RTLA), the U.S. Environmental Protection Agency, NOAA’s National Marine...
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Arctic Freshwater Synthesis: Summary of key emerging issues
NASA Astrophysics Data System (ADS)
Prowse, T.; Bring, A.; Mârd, J.; Carmack, E.; Holland, M.; Instanes, A.; Vihma, T.; Wrona, F. J.
2015-10-01
In response to a joint request from the World Climate Research Program's Climate and Cryosphere Project, the International Arctic Science Committee, and the Arctic Council's Arctic Monitoring and Assessment Program an updated scientific assessment has been conducted of the Arctic Freshwater System (AFS), entitled the Arctic Freshwater Synthesis (AFSΣ). The major reason behind the joint request was an increasing concern that changes to the AFS have produced, and could produce even greater, changes to biogeophysical and socioeconomic systems of special importance to northern residents and also produce extra-Arctic climatic effects that will have global consequences. The AFSΣ was structured around six key thematic areas: atmosphere, oceans, terrestrial hydrology, terrestrial ecology, resources, and modeling, the review of each coauthored by an international group of scientists and published as separate manuscripts in this special issue of Journal of Geophysical Research-Biogeosciences. This AFSΣ summary manuscript reviews key issues that emerged during the conduct of the synthesis, especially those that are cross-thematic in nature, and identifies future research required to address such issues.
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NASA Astrophysics Data System (ADS)
Liu, Y.; Hallberg, R.; Sergienko, O. V.; Samuels, B.; Harrison, M.; Oppenheimer, M.
2017-12-01
Greenland Ice Sheet (GIS) might have lost a large amount of its volume during the last interglacial and may do so again in the future due to climate warming. In this study, we show that the climate response to the GIS meltwater is sensitive to its discharging location initially but become insensitive after two to three hundred years. Two fully coupled atmosphere-ocean general circulation models, CM2G and CM2M, are employed to do the test. They differ in only their ocean components, one with isopycnal coordinate and the other with z-coordinate. The ocean components of both model are run at the nominal 1° horizontal resolution. In each experiment, a prescribed freshwater flux of 0.1 Sv is discharged into a single gridbox near one of the four locations around Greenland - Petermann, 79 North, Jacobshavn and Helheim glaciers. The results from both models show that the climate impact during the first two to three hundred years, in terms of AMOC and sea ice extent, is 15% (CM2G) and 31% (CM2M) stronger when the freshwater is discharged from the northern GIS (Petermann and 79 North) than when it is discharged from the southern GIS (Jacobshavn and Helheim). This is due to easier access of the freshwater from northern GIS to the deepwater formation site in the Nordic Seas. In the long term (>300 year), however, the climate impacts become similar for freshwater discharged from all locations of the GIS. The East Greenland current accelerates with time and becomes significantly faster when the freshwater is discharged from the north than from the south. Therefore, freshwater from the north is transported efficiently towards the south first and then circulates back to the the Nordic Seas, making its impact to the deepwater formation there similar to the freshwater discharged from the south. Our study demonstrates that if freshwater is injected into the ocean in a very localized form as in the real world, its ability to impact the deepwater formation evolves with time. At equilibrium state, the impact of freshwater from upstream of deepwater formation site is not necessarily larger than that from other locations, as obtained by relatively low-resolution models. This may have implication on the deglacial phase of glacial cycles, during which freshwater discharge often lasts for many hundreds of years, and often studied with low-resolution models.
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Metagenomics of the Water Column in the Pristine Upper Course of the Amazon River
McMahon, Katherine D.; Toyama, Danyelle; Rinke, Raquel; Cristina Souza de Oliveira, Tereza; Wagner Garcia, José; Pellon de Miranda, Fernando; Henrique-Silva, Flavio
2011-01-01
River water is a small percentage of the total freshwater on Earth but represents an essential resource for mankind. Microbes in rivers perform essential ecosystem roles including the mineralization of significant quantities of organic matter originating from terrestrial habitats. The Amazon river in particular is famous for its size and importance in the mobilization of both water and carbon out of its enormous basin. Here we present the first metagenomic study on the microbiota of this river. It presents many features in common with the other freshwater metagenome available (Lake Gatun in Panama) and much less similarity with marine samples. Among the microbial taxa found, the cosmopolitan freshwater acI lineage of the actinobacteria was clearly dominant. Group I Crenarchaea and the freshwater sister group of the marine SAR11 clade, LD12, were found alongside more exclusive and well known freshwater taxa such as Polynucleobacter. A metabolism-centric analysis revealed a disproportionate representation of pathways involved in heterotrophic carbon processing, as compared to those found in marine samples. In particular, these river microbes appear to be specialized in taking up and mineralizing allochthonous carbon derived from plant material. PMID:21915244
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Berger, Markus; van der Ent, Ruud; Eisner, Stephanie; Bach, Vanessa; Finkbeiner, Matthias
2014-04-15
Aiming to enhance the analysis of water consumption and resulting consequences along the supply chain of products, the water accounting and vulnerability evaluation (WAVE) model is introduced. On the accounting level, atmospheric evaporation recycling within drainage basins is considered for the first time, which can reduce water consumption volumes by up to 32%. Rather than predicting impacts, WAVE analyzes the vulnerability of basins to freshwater depletion. Based on local blue water scarcity, the water depletion index (WDI) denotes the risk that water consumption can lead to depletion of freshwater resources. Water scarcity is determined by relating annual water consumption to availability in more than 11,000 basins. Additionally, WDI accounts for the presence of lakes and aquifers which have been neglected in water scarcity assessments so far. By setting WDI to the highest value in (semi)arid basins, absolute freshwater shortage is taken into account in addition to relative scarcity. This avoids mathematical artifacts of previous indicators which turn zero in deserts if consumption is zero. As illustrated in a case study of biofuels, WAVE can help to interpret volumetric water footprint figures and, thus, promotes a sustainable use of global freshwater resources.
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Water withdrawals, use, and trends in Florida, 1985
Marella, R.L.
1988-01-01
Total water withdrawn for use in Florida for 1985, in million gal/day, was 17,057 of which 6,259, or nearly 37%, was freshwater and 10,798 was saline. The majority of freshwater withdrawn was groundwater (64%) and the majority of saline water withdrawn was surface water (99%). Thermoelectric power generation accounted for more than 99% of saline water withdrawals. Agricultural irrigation accounted for the majority of freshwater withdrawals for both groundwater (41%) and surface water (60%) in 1985. Between 1975-85, Florida 's population increased by nearly 3 million people; tourism increased by nearly 13 million visitors; irrigated agricultural acreage increased by 70,000; freshwater used to support those activities increased by almost 388 million gal/day (excluding fresh surface-water withdrawals for thermoelectric power generation); and fresh groundwater withdrawals increased 718 million gal/day. Groundwater accounted for 64% of Florida 's total freshwater use , up from 51% in 1980 and 48% in 1975. Florida ranked sixth in the Nation in groundwater withdrawals for 1985 with more than 4 ,000 million gal/day withdrawn. Groundwater is the primary source of freshwater in Florida because it is readily available and generally is suitable for most uses. The Floridan aquifer system, which underlies the entire State, supplied the majority (62%) of groundwater in Florida for 1985. In contrast to groundwater, withdrawals of surface water declined between 1975-85. (USGS)
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Aquatic Life Benchmarks and Ecological Risk Assessments for Registered Pesticides
Each Aquatic Life Benchmark is based on the most sensitive, scientifically acceptable toxicity endpoint available to EPA for a given taxon (for example, freshwater fish) of all scientifically acceptable toxicity data available to EPA.
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Betancur-R, Ricardo; Ortí, Guillermo; Pyron, Robert Alexander
2015-05-01
The marine-freshwater boundary is a major biodiversity gradient and few groups have colonised both systems successfully. Fishes have transitioned between habitats repeatedly, diversifying in rivers, lakes and oceans over evolutionary time. However, their history of habitat colonisation and diversification is unclear based on available fossil and phylogenetic data. We estimate ancestral habitats and diversification and transition rates using a large-scale phylogeny of extant fish taxa and one containing a massive number of extinct species. Extant-only phylogenetic analyses indicate freshwater ancestry, but inclusion of fossils reveal strong evidence of marine ancestry in lineages now restricted to freshwaters. Diversification and colonisation dynamics vary asymmetrically between habitats, as marine lineages colonise and flourish in rivers more frequently than the reverse. Our study highlights the importance of including fossils in comparative analyses, showing that freshwaters have played a role as refuges for ancient fish lineages, a signal erased by extinction in extant-only phylogenies. © 2015 John Wiley & Sons Ltd/CNRS.
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Evaluating water quality -- is it important, how can it be determined and how can it be used?
NASA Astrophysics Data System (ADS)
Leahy, P. P.
2015-12-01
Freshwater is critical to sustaining all life on Earth yet most humans take this resource for granted and often consider it a free good. However, in water-poor areas, the availability of clean drinking water limits economic development, negatively impacts human health and causes significant social instability. This was a driver for the Millennium Development Goals to include providing clean water to the developing world. Unlike other resources, another commodity cannot be substituted for water. In mineral resources, substitution is common depending on the use, for example, aluminum for steel in automotive bodies. In energy, humans can, in some instances, use natural gas instead of coal for electricity generation. Given the critical nature of freshwater for human existence, it is important that the resource be evaluated in economic terms. Although efforts to assess the value of the availability of freshwater have been developed, they are not commonly used. Water quality is also a major economic factor in availability of water resources. Quality can be prohibitively expensive to bring to acceptable standards and can easily be contaminated by human activities. Determining an economic and social value on both the availability and quality of water resources is a challenge that the hydrologic community must address at local, regional and national and even global scales to support informed policy and decision-making.
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A synthetic phylogeny of freshwater crayfish: insights for conservation.
Owen, Christopher L; Bracken-Grissom, Heather; Stern, David; Crandall, Keith A
2015-02-19
Phylogenetic systematics is heading for a renaissance where we shift from considering our phylogenetic estimates as a static image in a published paper and taxonomies as a hardcopy checklist to treating both the phylogenetic estimate and dynamic taxonomies as metadata for further analyses. The Open Tree of Life project (opentreeoflife.org) is developing synthesis tools for harnessing the power of phylogenetic inference and robust taxonomy to develop a synthetic tree of life. We capitalize on this approach to estimate a synthesis tree for the freshwater crayfish. The crayfish make an exceptional group to demonstrate the utility of the synthesis approach, as there recently have been a number of phylogenetic studies on the crayfishes along with a robust underlying taxonomic framework. Importantly, the crayfish have also been extensively assessed by an IUCN Red List team and therefore have accurate and up-to-date area and conservation status data available for analysis within a phylogenetic context. Here, we develop a synthesis phylogeny for the world's freshwater crayfish and examine the phylogenetic distribution of threat. We also estimate a molecular phylogeny based on all available GenBank crayfish sequences and use this tree to estimate divergence times and test for divergence rate variation. Finally, we conduct EDGE and HEDGE analyses and identify a number of species of freshwater crayfish of highest priority in conservation efforts. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
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NASA Astrophysics Data System (ADS)
Cusnir, Ruslan; Christl, Marcus; Steinmann, Philipp; Bochud, François; Froidevaux, Pascal
2017-06-01
The interaction of trace environmental plutonium with dissolved natural organic matter (NOM) plays an important role on its mobility and bioavailability in freshwater environments. Here we explore the speciation and biogeochemical behavior of Pu in freshwaters of the karst system in the Swiss Jura Mountains. Chemical extraction and ultrafiltration methods were complemented by diffusive gradients in thin films technique (DGT) to measure the dissolved and bioavailable Pu fraction in water. Accelerator mass spectrometry (AMS) was used to accurately determine Pu in this pristine environment. Selective adsorption of Pu (III, IV) on silica gel showed that 88% of Pu in the mineral water is found in +V oxidation state, possibly in a highly soluble [PuO2+(CO3)n]m- form. Ultrafiltration experiments at 10 kDa yielded a similar fraction of colloid-bound Pu in the organic-rich and in mineral water (18-25%). We also found that the concentrations of Pu measured by DGT in mineral water are similar to the bulk concentration, suggesting that dissolved Pu is readily available for biouptake. Sequential elution (SE) of Pu from aquatic plants revealed important co-precipitation of potentially labile Pu (60-75%) with calcite fraction within outer compartment of the plants. Hence, we suggest that plutonium is fully available for biological uptake in both mineral and organic-rich karstic freshwaters.
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A synthetic phylogeny of freshwater crayfish: insights for conservation
Owen, Christopher L.; Bracken-Grissom, Heather; Stern, David; Crandall, Keith A.
2015-01-01
Phylogenetic systematics is heading for a renaissance where we shift from considering our phylogenetic estimates as a static image in a published paper and taxonomies as a hardcopy checklist to treating both the phylogenetic estimate and dynamic taxonomies as metadata for further analyses. The Open Tree of Life project (opentreeoflife.org) is developing synthesis tools for harnessing the power of phylogenetic inference and robust taxonomy to develop a synthetic tree of life. We capitalize on this approach to estimate a synthesis tree for the freshwater crayfish. The crayfish make an exceptional group to demonstrate the utility of the synthesis approach, as there recently have been a number of phylogenetic studies on the crayfishes along with a robust underlying taxonomic framework. Importantly, the crayfish have also been extensively assessed by an IUCN Red List team and therefore have accurate and up-to-date area and conservation status data available for analysis within a phylogenetic context. Here, we develop a synthesis phylogeny for the world's freshwater crayfish and examine the phylogenetic distribution of threat. We also estimate a molecular phylogeny based on all available GenBank crayfish sequences and use this tree to estimate divergence times and test for divergence rate variation. Finally, we conduct EDGE and HEDGE analyses and identify a number of species of freshwater crayfish of highest priority in conservation efforts. PMID:25561670
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Agha, Mickey; Ennen, Joshua R; Bower, Deborah S; Nowakowski, A Justin; Sweat, Sarah C; Todd, Brian D
2018-03-25
The projected rise in global mean sea levels places many freshwater turtle species at risk of saltwater intrusion into freshwater habitats. Freshwater turtles are disproportionately more threatened than other taxa; thus, understanding the role of salinity in determining their contemporary distribution and evolution should be a research priority. Freshwater turtles are a slowly evolving lineage; however, they can adapt physiologically or behaviourally to various levels of salinity and, therefore, temporarily occur in marine or brackish environments. Here, we provide the first comprehensive global review on freshwater turtle use and tolerance of brackish water ecosystems. We link together current knowledge of geographic occurrence, salinity tolerance, phylogenetic relationships, and physiological and behavioural mechanisms to generate a baseline understanding of the response of freshwater turtles to changing saline environments. We also review the potential origins of salinity tolerance in freshwater turtles. Finally, we integrate 2100 sea level rise (SLR) projections, species distribution maps, literature gathered on brackish water use, and a phylogeny to predict the exposure of freshwater turtles to projected SLR globally. From our synthesis of published literature and available data, we build a framework for spatial and phylogenetic conservation prioritization of coastal freshwater turtles. Based on our literature review, 70 species (∼30% of coastal freshwater turtle species) from 10 of the 11 freshwater turtle families have been reported in brackish water ecosystems. Most anecdotal records, observations, and descriptions do not imply long-term salinity tolerance among freshwater turtles. Rather, experiments show that some species exhibit potential for adaptation and plasticity in physiological, behavioural, and life-history traits that enable them to endure varying periods (e.g. days or months) and levels of saltwater exposure. Species that specialize on brackish water habitats are likely to be vulnerable to SLR because of their exclusive coastal distributions and adaptations to a narrow range of salinities. Most species, however, have not been documented in brackish water habitats but may also be highly vulnerable to projected SLR. Our analysis suggests that approximately 90% of coastal freshwater turtle species assessed in our study will be affected by a 1-m increase in global mean SLR by 2100. Most at risk are freshwater turtles found in New Guinea, Southeast Asia, Australia, and North and South America that may lose more than 10% of their present geographic range. In addition, turtle species in the families Chelidae, Emydidae, and Trionychidae may experience the greatest exposure to projected SLR in their present geographic ranges. Better understanding of survival, growth, reproductive and population-level responses to SLR will improve region-specific population viability predictions of freshwater turtles that are increasingly exposed to SLR. Integrating phylogenetic, physiological, and spatial frameworks to assess the effects of projected SLR may improve identification of vulnerable species, guilds, and geographic regions in need of conservation prioritization. We conclude that the use of brackish and marine environments by freshwater turtles provides clues about the evolutionary processes that have prolonged their existence, shaped their unique coastal distributions, and may prove useful in predicting their response to a changing world. © 2018 Cambridge Philosophical Society.
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NASA Astrophysics Data System (ADS)
Koutroulis, A. G.; Grillakis, M. G.; Daliakopoulos, I. N.; Tsanis, I. K.; Jacob, D.
2016-01-01
Ensemble pan-European projections under a 2 °C global warming relative to the preindustrial period reveal a more intense warming in south Eastern Europe by up to +3 °C, thus indicating that impacts of climate change will be disproportionately high for certain regions. The Mediterranean is projected as one of the most vulnerable areas to climatic and anthropogenic changes with decreasing rainfall trends and a continuous gradual warming causing a progressive decline of average stream flow. Many Mediterranean regions are currently experiencing high to severe water stress induced by human and climate drivers. Changes in average climate conditions will increase this stress notably because of a 10-30% decline in freshwater resources. For small island states, where accessibility to freshwater resources is limited the impact will be more pronounced. Here we use a generalized cross-sectoral framework to assess the impact of climatic and socioeconomic futures on the water resources of an Eastern Mediterranean island. A set of representative regional climate models simulations from the EURO-CORDEX initiative driven by different RCP2.6, RCP4.5, and RCP8.5 GCMs are used to form a comparable set of results and a useful basis for the assessment of uncertainties related to impacts of 2° warming and above. A generalized framework of a cross-sectoral water resources analysis was developed in collaboration with the local water authority exploring and costing adaptation measures associated with a set of socioeconomic pathways (SSPs). Transient hydrological modeling was performed to describe the projected hydro-climatological regime and water availability for each warming level. The robust signal of less precipitation and higher temperatures that is projected by climate simulations results to a severe decrease of local water resources which can be mitigated by a number of actions. Awareness of the practical implications of plausible hydro-climatic and socio-economic scenarios in the not so distant future may be the key to shift perception and preference towards a more sustainable direction.
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NASA Astrophysics Data System (ADS)
Cooper, Gregory; Dearing, John
2017-04-01
Annual fish production from the Chilika lagoon is worth US25-million/year, underpinning the livelihoods of 35,000 fishers and 200,000 secondary dependants. The system has a legacy of collapse, transitioning from annual production rates of 9000 tonnes to 1300 tonnes during the late-1980s, with resulting livelihood losses triggering the first recorded instances of economic migration from Chilika. Despite engineered recovery since 2000, the future persistence of Chilika's resource stock is uncertain. Climate change may strengthen freshwater and sediment delivery, promoting ecohydrological degradation through tidal outlet sedimentation, reduced salinity and freshwater weed growth. Simultaneously, human population growth, fleet motorisation and consumption demands threaten overexploitation driven collapse. These critical social-ecological drivers and feedbacks are projected into future by integrating system dynamics modelling with Monte Carlo inputs. Sustainable pathways are identified from outputs producing social-ecologically desirable futures, such as mid-century catch equalling maximum sustainable yield. The 'safe and just operating space' metaphor is regionalised by the limits of sustainable trajectories, such as the permissible number of active fishers, motorised boats and juvenile catch under alternative governance scenarios. These critical thresholds suggest policy-relevant guardrails for the sustainable governance of Chilika, in order to avoid regional productivity collapse, ecological degradation and livelihood losses. Benefits and trade-offs of alternative governance approaches are also discussed, aiding the optimisation of future regulatory decision-making.
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Freshwater bacteria release methane as a byproduct of phosphorus acquisition.
Yao, Mengyin; Henny, Cynthia; Maresca, Julia A
2016-09-30
Freshwater lakes emit large amounts of methane, some of which is produced in oxic surface waters. Two potential pathways for aerobic methane production exist: methanogenesis in oxygenated water, which has been observed in some lakes, or demethylation of small organic molecules. Although methane is produced via demethylation in oxic marine environments, this mechanism of methane release has not yet been demonstrated in freshwater systems. Genes related to the C-P lyase pathway, which cleaves C-P bonds in phosphonate compounds, were found in a metagenomic survey of the surface water of Lake Matano, which is chronically P-starved and methane-rich. We demonstrate that four bacterial isolates from Lake Matano obtain P from methylphosphonate and release methane, and that this activity is repressed by phosphate. We further demonstrate that expression of phnJ, which encodes the enzyme that releases methane, is higher in the presence of methylphosphonate and lower when both methylphosphonate and phosphate are added. This gene is also found in most of the metagenomic data sets from freshwater environments. These experiments link methylphosphonate degradation and methane production with gene expression and phosphate availability in freshwater organisms, and suggest that some of the excess methane in the Lake Matano surface water, and in other methane-rich lakes, may be produced by P-starved bacteria. Methane is an important greenhouse gas, and contributes substantially to global warming. Although freshwater environments are known to release methane into the atmosphere, estimates of the amount of methane emitted by freshwater lakes vary from 8 to 73 Tg per year. Methane emissions are difficult to predict in part because the source of the methane can vary: it is the end product of the energy-conserving pathway in methanogenic archaea, which predominantly live in anoxic sediments or waters, but have also been identified in some oxic freshwater environments. More recently, methane release from small organic molecules has been observed in oxic marine environments. Here we show that demethylation of methylphosphonate may also contribute to methane release from lakes, and that phosphate can repress this activity. Since lakes are typically phosphorus-limited, some methane release in these environments may be a byproduct of phosphorus metabolism, rather than carbon or energy metabolism. Methane emissions from lakes are currently predicted using primary production, eutrophication status, extent of anoxia, and the shape and size of the lake; to improve prediction of methane emissions, phosphorus availability and sources may also need to be included in these models. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
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Wang, Hang; He, Zhili; Lu, Zhenmei; Zhou, Jizhong; Van Nostrand, Joy D.; Xu, Xinhua
2012-01-01
Rising climate temperatures in the future are predicted to accelerate the microbial decomposition of soil organic matter. A field microcosm experiment was carried out to examine the impact of soil warming in freshwater wetlands on different organic carbon (C) pools and associated microbial functional responses. GeoChip 4.0, a functional gene microarray, was used to determine microbial gene diversity and functional potential for C degradation. Experimental warming significantly increased soil pore water dissolved organic C and phosphorus (P) concentrations, leading to a higher potential for C emission and P export. Such losses of total organic C stored in soil could be traced back to the decomposition of recalcitrant organic C. Warming preferentially stimulated genes for degrading recalcitrant C over labile C. This was especially true for genes encoding cellobiase and mnp for cellulose and lignin degradation, respectively. We confirmed this with warming-enhanced polyphenol oxidase and peroxidase activities for recalcitrant C acquisition and greater increases in recalcitrant C use efficiency than in labile C use efficiency (average percentage increases of 48% versus 28%, respectively). The relative abundance of lignin-degrading genes increased by 15% under warming; meanwhile, soil fungi, as the primary decomposers of lignin, were greater in abundance by 27%. This work suggests that future warming may enhance the potential for accelerated fungal decomposition of lignin-like compounds, leading to greater microbially mediated C losses than previously estimated in freshwater wetlands. PMID:22923398
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The U.S. Environmental Protection Agency is currently developing methods to quantify freshwater fisheries services (e.g., standing-stock abundance and/or biomass) at multiple spatial scales, and to forecast their future distributions. One approach uses linked, ecosystem process ...
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REVIEW OF THE FISHERIES OF THE SALTON SEA, CALIFORNIA, USA: PAST, PRESENT, FUTURE. (R826552)
The Salton Sea is an endorheic, 980-km2 salt lake in the Sonoran Desert of southern California. The historical fish community switched from freshwater to marine species as salinity increased due to evaporation and brackish water inflows. Three species, bairdiella (<...
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NASA Astrophysics Data System (ADS)
Srinivasan, V.; Lambin, E. F.; Gorelick, S. M.; Thompson, B. H.; Rozelle, S.
2012-10-01
Freshwater scarcity has been cited as the major crisis of the 21st century, but it is surprisingly hard to describe the nature of the global water crisis. We conducted a meta-analysis of 22 coupled human-water system case studies, using qualitative comparison analysis (QCA) to identify water resource system outcomes and the factors that drive them. The cases exhibited different outcomes for human wellbeing that could be grouped into a six "syndromes": groundwater depletion, ecological destruction, drought-driven conflicts, unmet subsistence needs, resource capture by elite, and water reallocation to nature. For syndromes that were not successful adaptations, three characteristics gave cause for concern: (1) unsustainability—a decline in the water stock or ecosystem function that could result in a long-term steep decline in future human wellbeing; (2) vulnerability—high variability in water resource availability combined with inadequate coping capacity, leading to temporary drops in human wellbeing; (3) chronic scarcity—persistent inadequate access and hence low conditions of human wellbeing. All syndromes could be explained by a limited set of causal factors that fell into four categories: demand changes, supply changes, governance systems, and infrastructure/technology. By considering basins as members of syndrome classes and tracing common causal pathways of water crises, water resource analysts and planners might develop improved water policies aimed at reducing vulnerability, inequity, and unsustainability of freshwater systems.
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Silva-Junior, E F; Silva-Araújo, M; Moulton, T P
2017-11-01
Variations in physical characteristics along the course of a river influence habitat availability which reflects in species distribution. Knowledge of ecology and diversity of lotic species is important for evaluating how river ecosystems will respond to environmental impacts. Freshwater decapods are a group of high ecological and economic importance, but the knowledge about factors influencing their distribution is scarce in Brazil. We performed a survey of decapods to describe their abundance and distribution as well as to study their relationships with stream physical variables and especially their association with different substrates types. We studied 23 sites located in 15 tributaries of Guapiaçú River, RJ, where we collected decapods in different substrates types and measured a set of physical variables. We found five decapods species, including amphidromous and non-amphidromous shrimps and crabs. Decapods were strongly associated with leaf-litter substrates and their abundance was related to a multivariate axis describing longitudinal changes in stream characteristics. We concluded that decapods occurring in the Guapiaçú catchment inhabit mainly small streams with preserved riparian forests where they find shelter and potential prey of invertebrates. The ongoing project to build a dam on the Guapiaçú River will have negative consequences to migrating shrimps and we strongly recommend that mitigating actions, such the construction of structures to allow the passage of migrating fauna, should be taken.
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A commentary on the Atlantic meridional overturning circulation stability in climate models
NASA Astrophysics Data System (ADS)
Gent, Peter R.
2018-02-01
The stability of the Atlantic meridional overturning circulation (AMOC) in ocean models depends quite strongly on the model formulation, especially the vertical mixing, and whether it is coupled to an atmosphere model. A hysteresis loop in AMOC strength with respect to freshwater forcing has been found in several intermediate complexity climate models and in one fully coupled climate model that has very coarse resolution. Over 40% of modern climate models are in a bistable AMOC state according to the very frequently used simple stability criterion which is based solely on the sign of the AMOC freshwater transport across 33° S. In a recent freshwater hosing experiment in a climate model with an eddy-permitting ocean component, the change in the gyre freshwater transport across 33° S is larger than the AMOC freshwater transport change. This casts very strong doubt on the usefulness of this simple AMOC stability criterion. If a climate model uses large surface flux adjustments, then these adjustments can interfere with the atmosphere-ocean feedbacks, and strongly change the AMOC stability properties. AMOC can be shut off for many hundreds of years in modern fully coupled climate models if the hosing or carbon dioxide forcing is strong enough. However, in one climate model the AMOC recovers after between 1000 and 1400 years. Recent 1% increasing carbon dioxide runs and RCP8.5 future scenario runs have shown that the AMOC reduction is smaller using an eddy-resolving ocean component than in the comparable standard 1° ocean climate models.
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Mycorrhizal colonization across hydrologic gradients in restored and reference freshwater wetlands
Bauer, C.R.; Kellogg, C.H.; Bridgham, S.D.; Lamberti, G.A.
2003-01-01
Arbuscular mycorrhizae, which are plant root-fungal symbioses, are common associates of vascular plants. Such relationships, however, are thought to be rare in wetland plant roots, although several recent studies suggest that arbuscular mycorrhizae may be important in wetland ecosystems. Our objectives were to determine (1) the level of arbuscular mycorrhizal colonization of plant roots in three freshwater marshes and (2) the effect of restoration status, hydrologic zone, and plant species identity on mycorrhizal colonization. We quantified the percentage of plant roots colonized by mycorrhizal fungi in one reference and two restored freshwater marshes in northern Indiana, USA during summer 1999. Roots were collected from soil cores taken around dominant plant species present in each of three hydrologic zones and then stained for microscopic examination of mycorrhizal colonization. Mycorrhizae were present in each wetland, in all hydrologic zones and in all sampled plants, including Carex and Scirpus species previously thought to be non-mycorrhizal. Both restored and reference wetlands had moderate levels of mycorrhizal colonization, but no clear trends in colonization were seen with hydrologic zone, which has been hypothesized to regulate the formation of mycorrhizae in wetlands. Mycorrhizal colonization levels in the roots of individual species ranged from 3 to 90% and were particularly large in members of the Poaceae (grass) family. Our results suggest that arbuscular mycorrhizae may be widely distributed across plant species and hydrologic zones in both restored and reference freshwater marshes. Thus, future research should examine the functional role of mycorrhizal fungi in freshwater wetlands. ?? 2003, The Society of Wetland Scientists.
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Rates and patterns of molecular evolution in freshwater versus terrestrial insects.
Mitterboeck, T Fatima; Fu, Jinzhong; Adamowicz, Sarah J
2016-11-01
Insect lineages have crossed between terrestrial and aquatic habitats many times, for both immature and adult life stages. We explore patterns in molecular evolutionary rates between 42 sister pairs of related terrestrial and freshwater insect clades using publicly available protein-coding DNA sequence data from the orders Coleoptera, Diptera, Lepidoptera, Hemiptera, Mecoptera, Trichoptera, and Neuroptera. We furthermore test for habitat-associated convergent molecular evolution in the cytochrome c oxidase subunit I (COI) gene in general and at a particular amino acid site previously reported to exhibit habitat-linked convergence within an aquatic beetle group. While ratios of nonsynonymous-to-synonymous substitutions across available loci were higher in terrestrial than freshwater-associated taxa in 26 of 42 lineage pairs, a stronger trend was observed (20 of 31, p binomial = 0.15, p Wilcoxon = 0.017) when examining only terrestrial-aquatic pairs including fully aquatic taxa. We did not observe any widespread changes at particular amino acid sites in COI associated with habitat shifts, although there may be general differences in selection regime linked to habitat.
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Romañach, Stephanie S.; Conzelmann, Craig; Daugherty, Adam; Lorenz, Jerome L.; Hunnicutt, Christina; Mazzotti, Frank J.
2011-01-01
Estuarine fish serve as an important prey base in the Greater Everglades ecosystem for key fauna such as wading birds, crocodiles, alligators, and piscivorous fishes. Human-made changes to freshwater flow across the Greater Everglades have resulted in less freshwater flow into the fringing estuaries and coasts. These changes in freshwater input have altered salinity patterns and negatively affected primary production of the estuarine fish prey base. Planned restoration projects should affect salinity and water depth both spatially and temporally and result in an increase in appropriate water conditions in areas occupied by estuarine fish. To assist in restoration planning, an ecological model of estuarine prey fish biomass availability was developed as an evaluation tool to aid in the determination of acceptable ranges of salinity and water depth. Comparisons of model output to field data indicate that the model accurately predicts prey biomass in the estuarine regions of the model domain. This model can be used to compare alternative restoration plans and select those that provide suitable conditions.
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NASA Astrophysics Data System (ADS)
Betrie, G.; Yan, E.; Clark, C.
2016-12-01
Thermoelectric power plants use the highest amount of freshwater second to the agriculture sector. However, there is scarcity of information that characterizes the freshwater use of these plants in the United States. This could be attributed to the lack of model and data that are required to conduct analysis and gain insights. The competition for freshwater among sectors will increase in the future as the amount of freshwater gets limited due climate change and population growth. A model that makes use of less data is urgently needed to conduct analysis and identify adaptation strategies. The objectives of this study are to develop a model and simulate the water use of thermoelectric power plants in the United States. The developed model has heat-balance, climate, cooling system, and optimization modules. It computes the amount of heat rejected to the environment, estimates the quantity of heat exchanged through latent and sensible heat to the environment, and computes the amount of water required per unit generation of electricity. To verify the model, we simulated a total of 876 fossil-fired, nuclear and gas-turbine power plants with different cooling systems (CS) using 2010-2014 data obtained from Energy Information Administration. The CS includes once-through with cooling pond, once-through without cooling ponds, recirculating with induced draft and recirculating with induced draft natural draft. The results show that the model reproduced the observed water use per unit generation of electricity for the most of the power plants. It is also noticed that the model slightly overestimates the water use during the summer period when the input water temperatures are higher. We are investigating the possible reasons for the overestimation and address it in the future work. The model could be used individually or coupled to regional models to analyze various adaptation strategies and improve the water use efficiency of thermoelectric power plants.
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Moyle, Peter B; Kiernan, Joseph D; Crain, Patrick K; Quiñones, Rebecca M
2013-01-01
Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a systematic assessment approach that incorporates expert knowledge was developed to determine status and future vulnerability to climate change of freshwater fishes in California, USA. The method uses expert knowledge, supported by literature reviews of status and biology of the fishes, to score ten metrics for both (1) current status of each species (baseline vulnerability to extinction) and (2) likely future impacts of climate change (vulnerability to extinction). Baseline and climate change vulnerability scores were derived for 121 native and 43 alien fish species. The two scores were highly correlated and were concordant among different scorers. Native species had both greater baseline and greater climate change vulnerability than did alien species. Fifty percent of California's native fish fauna was assessed as having critical or high baseline vulnerability to extinction whereas all alien species were classified as being less or least vulnerable. For vulnerability to climate change, 82% of native species were classified as highly vulnerable, compared with only 19% for aliens. Predicted climate change effects on freshwater environments will dramatically change the fish fauna of California. Most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction. Fishes requiring cold water (<22°C) are particularly likely to go extinct. In contrast, most alien fishes will thrive, with some species increasing in abundance and range. However, a few alien species will likewise be negatively affected through loss of aquatic habitats during severe droughts and physiologically stressful conditions present in most waterways during summer. Our method has high utility for predicting vulnerability to climate change of diverse fish species. It should be useful for setting conservation priorities in many different regions.
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Moyle, Peter B.; Kiernan, Joseph D.; Crain, Patrick K.; Quiñones, Rebecca M.
2013-01-01
Freshwater fishes are highly vulnerable to human-caused climate change. Because quantitative data on status and trends are unavailable for most fish species, a systematic assessment approach that incorporates expert knowledge was developed to determine status and future vulnerability to climate change of freshwater fishes in California, USA. The method uses expert knowledge, supported by literature reviews of status and biology of the fishes, to score ten metrics for both (1) current status of each species (baseline vulnerability to extinction) and (2) likely future impacts of climate change (vulnerability to extinction). Baseline and climate change vulnerability scores were derived for 121 native and 43 alien fish species. The two scores were highly correlated and were concordant among different scorers. Native species had both greater baseline and greater climate change vulnerability than did alien species. Fifty percent of California’s native fish fauna was assessed as having critical or high baseline vulnerability to extinction whereas all alien species were classified as being less or least vulnerable. For vulnerability to climate change, 82% of native species were classified as highly vulnerable, compared with only 19% for aliens. Predicted climate change effects on freshwater environments will dramatically change the fish fauna of California. Most native fishes will suffer population declines and become more restricted in their distributions; some will likely be driven to extinction. Fishes requiring cold water (<22°C) are particularly likely to go extinct. In contrast, most alien fishes will thrive, with some species increasing in abundance and range. However, a few alien species will likewise be negatively affected through loss of aquatic habitats during severe droughts and physiologically stressful conditions present in most waterways during summer. Our method has high utility for predicting vulnerability to climate change of diverse fish species. It should be useful for setting conservation priorities in many different regions. PMID:23717503
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Towards saving freshwater: halophytes as unconventional feedstuffs in livestock feed: a review.
Abd El-Hack, Mohamed E; Samak, Dalia H; Noreldin, Ahmed E; Arif, Muhammad; Yaqoob, Hilal S; Swelum, Ayman A
2018-04-26
Water represents 71% of all earth area and about 97% of this water is salty water. So, only 3% of the overall world water quantity is freshwater. Human can benefit only from 1% of this water and the remaining 2% freeze at both poles of earth. Therefore, it is important to preserve the freshwater through increasing the plants consuming salty water. The future prosperity of feed resources in arid and semi-arid countries depends on economic use of alternative resources that have been marginalized for long periods of time, such as halophytic plants, which are one such potential future resource. Halophyte plants can grow in high salinity water and soil and to some extent during drought. The growth of these plants depends on the contact of the salted water with plant roots as in semi-desert saline water, mangrove swamps, marshes, and seashores. Halophyte plants need high levels of sodium chloride in the soil water for growth, and the soil water must also contain high levels of salts, as sodium hydroxide or magnesium sulfate. There are many uses for halophyte plants, including feed for animals, vegetables, drugs, sand dune stabilizers, wind shelter, soil cover, wetland cultivation, laundry detergents, and paper production. This paper will focus on the use of halophytes as a feed additive for animals. In spite of the good nutritional value of halophytes, some anti-nutritional factors as nitrates, nitrite complexes, tannins, glycosides, phenolic compounds, saponins, oxalates, and alkaloids may be present in some of them. The presence of such anti-nutritional agents makes halophytes unpalatable to animals, which tends to reduce feed intake and nutrient use. Therefore, the negative effects of these plants on animal performance are the only objection against using halophytes in animal feed diets. This review article highlights the beneficial impact of considering halophytes in animal feeding on saving freshwater and illustrates its nutritive value for livestock from different aspects.
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Thongprajukaew, Karun; Yawang, Pinya; Dudae, Lateepah; Bilanglod, Husna; Dumrongrittamatt, Terdtoon; Tantikitti, Chutima; Kovitvadhi, Uthaiwan
2013-12-01
Unavailable carbohydrates are an important limiting factor for utilization of palm kernel meal (PKM) as aquafeed ingredients. The aim of this study was to improve available carbohydrate from PKM. Different physical modifications including water soaking, microwave irradiation, gamma irradiation and electron beam, were investigated in relation to chemical composition, physicochemical properties and in vitro carbohydrate digestibility using digestive enzymes from economic freshwater fish. Modified methods had significant (P < 0.05) effects on chemical composition by decreasing crude fiber and increasing available carbohydrates. Improvements in physicochemical properties of PKM, such as water solubility, microstructure, relative crystallinity and lignocellulosic spectra, were mainly achieved by soaking and microwave irradiation. Carbohydrate digestibility varied among the physical modifications tested (P < 0.05) and three fish species had different abilities to digest PKM. Soaking was the appropriate modification for increasing carbohydrate digestion specifically in Nile tilapia (Oreochromis niloticus), whereas either soaking or microwave irradiation was effective for striped snakehead (Channa striata). For walking catfish (Clarias batrachus), carbohydrate digestibility was similar among raw, soaked and microwave-irradiated PKM. These findings suggest that soaking and microwave irradiation could be practical methods for altering appropriate physicochemical properties of PKM as well as increasing carbohydrate digestibility in select economic freshwater fish. © 2013 Society of Chemical Industry.
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[Book Review] Bykhovskaya-Pavllvskaya: Key to parasites of freshwater fish of the U.S.S.R
Hoffman, G.L.
1966-01-01
Review of: Key to parasites of freshwater fish of the U.S.S.R. Opredelitel' parazitov presnovodnykh ryb SSSR. Compiled by I. E. Bykhovskaya-Pavlovskaya [and others] Assisted by L. F. Nagibina, E. V. Baikova, and Yu. A. Strelkov. Chief Editor: E. N. Pavlovskii. Translated from Russian [by A. Birron and Z.S. Cole] Published 1964 by Israel Program for Scientific Translations, [available from the Office of Technical Services, U.S. Dept. of Commerce, Washington] in Jerusalem.
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2007-11-01
availability in the water column, and serve as habitat and food sources for invertebrates, fish, and waterfowl. Many SAV communities in freshwater ...Journal of Freshwater Ecology 10: 19-31. Carr, G. M., H. C. Duthie, and W. D. Taylor. 1997. Models of aquatic plant productivity and growth: A review of...and its effects on aquatic macrophytes in flowing waters . Ecological Applications 1: 249-257. Collins, C. D., and J. H. Wlosinski. 1985. A
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Determining Regional Sensitivity to Energy-Related Water Withdrawals in Minnesota
NASA Astrophysics Data System (ADS)
McCulloch, A.; Brauman, K. A.
2015-12-01
Minnesota has abundant freshwater resources, yet concerns about water-impacts of energy and mining development are increasing. Statewide, total annual water withdrawals have increased, and, in some watersheds, withdrawals make up a large fraction of available water. The energy and mining sectors play a critical role in determining water availability, as water is used to irrigate biofuel feedstock crops, cool thermoelectric plants, and process and transport fuels and iron ore. We evaluated the Minnesota Department of Natural Resources (DNR) Water and Reporting System (MPARS) dataset (1988-2014) to identify regions where energy and mining-related water withdrawals are high or where they are increasing. The energy and mining sectors account for over 65 percent of total water extractions in Minnesota, but this percentage is greater in some regions. In certain southern and northeastern Minnesota watersheds, these extractions account for 90 percent of total water demand. Sensitivity to these demands is not dependent on total water demand alone, and is also not uniform among watersheds. We identified and evaluated factors influencing sensitivity, including population, extraction type (surface water or groundwater), percentage of increased demand, and whether withdrawals are consumptive or not. We determined that southern Minnesota is particularly sensitive to increased water demands, because of growing biofuel and sand extraction industries (the products of which are used in hydraulic fracturing). In the last ten years, ethanol production in Minnesota has increased by 440 percent, and over fifteen refineries (each with a capacity over 1.1 billion gallons), have been built. These users primarily extract from surface water bodies within a few watersheds, compromising local supplies. As these energy-related industries continue to grow, so will the demand for freshwater resources. Determining regional sensitivity to increased demands will allow policy-makers to manage the increased competition for Minnesota's future water supplies.
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NASA Astrophysics Data System (ADS)
Pulido-Velazquez, David; Renau-Pruñonosa, Arianna; Llopis-Albert, Carlos; Morell, Ignacio; Collados-Lara, Antonio-Juan; Senent-Aparicio, Javier; Baena-Ruiz, Leticia
2018-05-01
Any change in the components of the water balance in a coastal aquifer, whether natural or anthropogenic, can alter the freshwater-salt water equilibrium. In this sense climate change (CC) and land use and land cover (LULC) change might significantly influence the availability of groundwater resources in the future. These coastal systems demand an integrated analysis of quantity and quality issues to obtain an appropriate assessment of hydrological impacts using density-dependent flow solutions. The aim of this work is to perform an integrated analysis of future potential global change (GC) scenarios and their hydrological impacts in a coastal aquifer, the Plana Oropesa-Torreblanca aquifer. It is a Mediterranean aquifer that extends over 75 km2 in which important historical LULC changes have been produced and are planned for the future. Future CC scenarios will be defined by using an equi-feasible and non-feasible ensemble of projections based on the results of a multi-criteria analysis of the series generated from several regional climatic models with different downscaling approaches. The hydrological impacts of these CC scenarios combined with future LULC scenarios will be assessed with a chain of models defined by a sequential coupling of rainfall-recharge models, crop irrigation requirements and irrigation return models (for the aquifer and its neighbours that feed it), and a density-dependent aquifer approach. This chain of models, calibrated using the available historical data, allow testing of the conceptual approximation of the aquifer behaviour. They are also fed with series representatives of potential global change scenarios in order to perform a sensitivity analysis regarding future scenarios of rainfall recharge, lateral flows coming from the hydraulically connected neighbouring aquifer, agricultural recharge (taking into account expected future LULC changes) and sea level rise (SLR). The proposed analysis is valuable for improving our knowledge about the aquifer, and so comprises a tool to design sustainable adaptation management strategies taking into account the uncertainty in future GC conditions and their impacts. The results show that GC scenarios produce significant increases in the variability of flow budget components and in the salinity.
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3D Dynamics of the Near-Surface Layer of the Ocean in the Presence of Freshwater Influx
NASA Astrophysics Data System (ADS)
Dean, C.; Soloviev, A.
2015-12-01
Freshwater inflow due to convective rains or river runoff produces lenses of freshened water in the near surface layer of the ocean. These lenses are localized in space and typically involve both salinity and temperature anomalies. Due to significant density anomalies, strong pressure gradients develop, which result in lateral spreading of freshwater lenses in a form resembling gravity currents. Gravity currents inherently involve three-dimensional dynamics. The gravity current head can include the Kelvin-Helmholtz billows with vertical density inversions. In this work, we have conducted a series of numerical experiments using computational fluid dynamics tools. These numerical simulations were designed to elucidate the relationship between vertical mixing and horizontal advection of salinity under various environmental conditions and potential impact on the pollution transport including oil spills. The near-surface data from the field experiments in the Gulf of Mexico during the SCOPE experiment were available for validation of numerical simulations. In particular, we observed a freshwater layer within a few-meter depth range and, in some cases, a density inversion at the edge of the freshwater lens, which is consistent with the results of numerical simulations. In conclusion, we discuss applicability of these results to the interpretation of Aquarius and SMOS sea surface salinity satellite measurements. The results of this study indicate that 3D dynamics of the near-surface layer of the ocean are essential in the presence of freshwater inflow.
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Andrade, Ana Camila; Fróes, Adriana; Lopes, Fabyano Álvares Cardoso; Thompson, Fabiano L; Krüger, Ricardo Henrique; Dinsdale, Elizabeth; Bruce, Thiago
2017-07-01
Semi-arid and arid areas occupy about 33% of terrestrial ecosystems. However, little information is available about microbial diversity in the semi-arid Caatinga, which represents a unique biome that extends to about 11% of the Brazilian territory and is home to extraordinary diversity and high endemism level of species. In this study, we characterized the diversity of microbial genes associated with biomass conversion (carbohydrate-active enzymes, or so-called CAZYmes) in soil and freshwater of the Caatinga. Our results showed distinct CAZYme profiles in the soil and freshwater samples. Glycoside hydrolases and glycosyltransferases were the most abundant CAZYme families, with glycoside hydrolases more dominant in soil (∼44%) and glycosyltransferases more abundant in freshwater (∼50%). The abundances of individual glycoside hydrolase, glycosyltransferase, and carbohydrate-binding module subfamilies varied widely between soil and water samples. A predominance of glycoside hydrolases was observed in soil, and a higher contribution of enzymes involved in carbohydrate biosynthesis was observed in freshwater. The main taxa associated with the CAZYme sequences were Planctomycetia (relative abundance in soil, 29%) and Alphaproteobacteria (relative abundance in freshwater, 27%). Approximately 5-7% of CAZYme sequences showed low similarity with sequences deposited in non-redundant databases, suggesting putative homologues. Our findings represent a first attempt to describe specific microbial CAZYme profiles for environmental samples. Characterizing these enzyme groups associated with the conversion of carbohydrates in nature will improve our understanding of the significant roles of enzymes in the carbon cycle. We identified a CAZYme signature that can be used to discriminate between soil and freshwater samples, and this signature may be related to the microbial species adapted to the habitat. The data show the potential ecological roles of the CAZYme repertoire and associated biotechnological applications.
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NASA Astrophysics Data System (ADS)
Longo, William M.; Theroux, Susanna; Giblin, Anne E.; Zheng, Yinsui; Dillon, James T.; Huang, Yongsong
2016-05-01
Alkenones are a class of unsaturated long-chain ketone biomarkers that have been used to reconstruct sea surface temperature and, more recently, continental temperature, by way of alkenone unsaturation indices (e.g. U37K and U37K‧). Alkenones are frequently found in brackish and saline lakes, however species effects confound temperature reconstructions when multiple alkenone-producing species with different temperature responses are present. Interestingly, available genetic data indicate that numerous freshwater lakes host a distinct phylotype of alkenone-producing haptophyte algae (the Group I or Greenland phylotype), providing evidence that species effects may be diminished in freshwater lakes. These findings encourage further investigation of alkenone paleotemperature proxies in freshwater systems. Here, we investigated lakes from northern Alaska (n = 35) and show that alkenones commonly occurred in freshwater lakes, where they featured distinct distributions, characterized by dominant C37:4 alkenones and a series of tri-unsaturated alkenone isomers. The distributions were characteristic of Group I-type alkenone distributions previously identified in Greenland and North America. Our analysis of suspended particulate matter from Toolik Lake (68° 38‧N, 149° 36‧W) yielded the first in situ freshwater U37K calibration (U37K = 0.021 * T - 0.68; r2 = 0.85; n = 52; RMSE = ±1.37 °C). We explored the environmental significance of the tri-unsaturated isomers using our northern Alaskan lakes dataset in conjunction with new data from haptophyte cultures and Canadian surface sediments. Our results show that these temperature-sensitive isomers are biomarkers for the Group I phylotype and indicators of multiple-species effects. Together, these findings highlight freshwater lakes as valuable targets for continental alkenone-based paleotemperature reconstructions and demonstrate the significance of the recently discovered tri-unsaturated isomers.
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Hejazian, Mehrdad; Gurdak, Jason J.; Swarzenski, Peter W.; Odigie, Kingsley; Storlazzi, Curt
2017-01-01
Freshwater resources on low-lying atoll islands are highly vulnerable to climate change and sea-level rise. In addition to rainwater catchment, groundwater in the freshwater lens is a critically important water resource on many atoll islands, especially during drought. Although many atolls have high annual rainfall rates, dense natural vegetation and high evapotranspiration rates can limit recharge to the freshwater lens. Here we evaluate the effects of land-use/land-cover change and managed aquifer recharge on the hydrogeochemistry and supply of groundwater on Roi-Namur Island, Republic of the Marshall Islands. Roi-Namur is an artificially conjoined island that has similar hydrogeology on the Roi and Namur lobes, but has contrasting land-use/land-cover and managed aquifer recharge only on Roi. Vegetation removal and managed aquifer recharge operations have resulted in an estimated 8.6 x 105 m3 of potable groundwater in the freshwater lens on Roi, compared to only 1.6 x 104 m3 on Namur. We use groundwater samples from a suite of 33 vertically nested monitoring wells, statistical testing, and geochemical modeling using PHREEQC to show that the differences in land-use/land-cover and managed aquifer recharge on Roi and Namur have a statistically significant effect on several groundwater-quality parameters and the controlling geochemical processes. Results also indicate a seven-fold reduction in the dissolution of carbonate rock in the freshwater lens and overlying vadose zone of Roi compared to Namur. Mixing of seawater and the freshwater lens is a more dominant hydrogeochemical process on Roi because of the greater recharge and flushing of the aquifer with freshwater as compared to Namur. In contrast, equilibrium processes and dissolution-precipitation non-equilibrium reactions are more dominant on Namur because of the longer residence times relative to the rate of geochemical reactions. Findings from Roi-Namur Island support selective land-use/land-cover change and managed aquifer recharge as a promising management approach for communities on other low-lying atoll islands to increase the resilience of their groundwater supplies and help them adapt to future climate change related stresses.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Condron, Alan
In the present-day North Atlantic Ocean, relatively warm and salty water moves northwards from the tropics to the high latitudes, sinks, and returns southward towards the equator as North Atlantic Deep Water, forming the so called Atlantic Meridional Overturning Circulation (AMOC). It has been found that the stability of the AMOC is non-linearly related to the freshwater budget of the North Atlantic. In this way, additional fresh water can be added to the ocean with little impact, until a tipping point is reached that causes the AMOC to suddenly weaken and the Northern Hemisphere to abruptly cool. A great dealmore » of uncertainty still remains over the sensitivity of the AMOC to changes in freshwater discharge as a result of the unrealistic manner in which freshwater has historically been added to climate models. Frequently, freshwater is discharged in ocean models entirely as liquid water, but in reality a large fraction of freshwater entering the ocean is ice calving from marine glaciers (half for Antarctica and two-thirds for Greenland). To more accurately quantify AMOC sensitivity to past and future changes in freshwater input, this project developed a comprehensive iceberg model to more realistically simulate the interaction between the cryosphere and the oceans at high-latitudes. The iceberg model created is written in Fortran90 and designed to scale efficiently on High Performance Computing (HPC) clusters so that tens-of-thousands of icebergs can be simulated at any time. Experiments performed with our model showed that in the Pleistocene there would have been enormous floods of freshwater released into the North Atlantic that would have transported icebergs and meltwater along the entire east coast of the United States, as far south as Florida Keys. In addition, high-resolution, modern-day, model simulations showed that if the Greenland Ice Sheet continues to melt at its current rate then there will be a 6-fold increase in the number of icebergs drifting in the North Atlantic in the next 30 years, and that the strength of the AMOC could weaken by 3.5%.« less
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Analysis of the Arctic system for freshwater cycle intensification: Observations and expectations
Rawlins, M.A.; Steele, M.; Holland, M.M.; Adam, J.C.; Cherry, J.E.; Francis, J.A.; Groisman, P.Y.; Hinzman, L.D.; Huntington, T.G.; Kane, D.L.; Kimball, J.S.; Kwok, R.; Lammers, R.B.; Lee, C.M.; Lettenmaier, D.P.; McDonald, K.C.; Podest, E.; Pundsack, J.W.; Rudels, B.; Serreze, Mark C.; Shiklomanov, A.; Skagseth, O.; Troy, T.J.; Vorosmarty, C.J.; Wensnahan, M.; Wood, E.F.; Woodgate, R.; Yang, D.; Zhang, K.; Zhang, T.
2010-01-01
Hydrologic cycle intensification is an expected manifestation of a warming climate. Although positive trends in several global average quantities have been reported, no previous studies have documented broad intensification across elements of the Arctic freshwater cycle (FWC). In this study, the authors examine the character and quantitative significance of changes in annual precipitation, evapotranspiration, and river discharge across the terrestrial pan-Arctic over the past several decades from observations and a suite of coupled general circulation models (GCMs). Trends in freshwater flux and storage derived from observations across the Arctic Ocean and surrounding seas are also described. With few exceptions, precipitation, evapotranspiration, and river discharge fluxes from observations and the GCMs exhibit positive trends. Significant positive trends above the 90% confidence level, however, are not present for all of the observations. Greater confidence in the GCM trends arises through lower interannual variability relative to trend magnitude. Put another way, intrinsic variability in the observations tends to limit confidence in trend robustness. Ocean fluxes are less certain, primarily because of the lack of long-term observations. Where available, salinity and volume flux data suggest some decrease in saltwater inflow to the Barents Sea (i.e., a decrease in freshwater outflow) in recent decades. A decline in freshwater storage across the central Arctic Ocean and suggestions that large-scale circulation plays a dominant role in freshwater trends raise questions as to whether Arctic Ocean freshwater flows are intensifying. Although oceanic fluxes of freshwater are highly variable and consistent trends are difficult to verify, the other components of the Arctic FWC do show consistent positive trends over recent decades. The broad-scale increases provide evidence that the Arctic FWC is experiencing intensification. Efforts that aim to develop an adequate observation system are needed to reduce uncertainties and to detect and document ongoing changes in all system components for further evidence of Arctic FWC intensification.
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Dehydration and drinking behavior of the marine file snake Acrochordus granulatus.
Lillywhite, Harvey B; Heatwole, Harold; Sheehy, Coleman M
2014-01-01
Dehydration and drinking behaviors were investigated in the little file snake (Acrochordus granulatus) collected from marine populations in the Philippines and in Australia. File snakes dehydrate in seawater and do not drink seawater when dehydrated in air and offered seawater to drink. Dehydrated file snakes drink freshwater, and the threshold of dehydration for first drinking response is a deficit of -7.4% ± 2.73% (mean ± SD) of original body mass. The thirst mechanism in this species is more sensitive than that recently studied in sea snakes. The volume of water ingested increases with increasing dehydration. Mean plasma osmolality was 278.89 ± 33.17 mMol/kg, mean hematocrit was 59% ± 5.45%, and both decreased in snakes that drank freshwater following acclimation in seawater. Snakes always drank freshwater at the water's surface, testing water with tongue flicks between each swallowing of water. Some snakes ingested large volumes of freshwater, approaching 50% of body mass. Visual observations and measurements of osmolality in plasma and stomach fluids suggest that water is taken up from the gut and dilutes body fluids slowly over the course of 48 h or longer. Eighty percent of snakes that were collected during the dry season (following >4 mo of drought) in Australia drank freshwater immediately following their capture, indicating that snakes were dehydrated in their marine environment even when known to have been feeding at the time. Snakes kept in seawater maintained a higher state of body condition when freshwater was periodically available. These results support a growing conclusion that diverse taxa of marine snakes require environmental sources of freshwater to maintain water balance, contrary to earlier belief. Identifying the freshwater requirements of secondarily marine vertebrates is important for better understanding how they maintain water balance in marine habitats, especially with respect to conservation in changing environments.
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Enhancing protection for vulnerable waters
NASA Astrophysics Data System (ADS)
Creed, Irena F.; Lane, Charles R.; Serran, Jacqueline N.; Alexander, Laurie C.; Basu, Nandita B.; Calhoun, Aram J. K.; Christensen, Jay R.; Cohen, Matthew J.; Craft, Christopher; D'Amico, Ellen; Dekeyser, Edward; Fowler, Laurie; Golden, Heather E.; Jawitz, James W.; Kalla, Peter; Kirkman, L. Katherine; Lang, Megan; Leibowitz, Scott G.; Lewis, David B.; Marton, John; McLaughlin, Daniel L.; Raanan-Kiperwas, Hadas; Rains, Mark C.; Rains, Kai C.; Smith, Lora
2017-11-01
Governments worldwide do not adequately protect their limited freshwater systems and therefore place freshwater functions and attendant ecosystem services at risk. The best available scientific evidence compels enhanced protections for freshwater systems, especially for impermanent streams and wetlands outside of floodplains that are particularly vulnerable to alteration or destruction. New approaches to freshwater sustainability -- implemented through scientifically informed adaptive management -- are required to protect freshwater systems through periods of changing societal needs. One such approach introduced in the US in 2015 is the Clean Water Rule, which clarified the jurisdictional scope for federally protected waters. However, within hours of its implementation litigants convinced the US Court of Appeals for the Sixth Circuit to stay the rule, and the subsequently elected administration has now placed it under review for potential revision or rescission. Regardless of its outcome at the federal level, policy and management discussions initiated by the propagation of this rare rulemaking event have potential far-reaching implications at all levels of government across the US and worldwide. At this timely juncture, we provide a scientific rationale and three policy options for all levels of government to meaningfully enhance protection of these vulnerable waters. A fourth option, a 'do-nothing' approach, is wholly inconsistent with the well-established scientific evidence of the importance of these vulnerable waters.
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Water Availability and Management of Water Resources
One of the most pressing national and global issues is the availability of freshwater due to global climate change, energy scarcity issues and the increase in world population and accompanying economic growth. Estimates of water supplies and flows through the world's hydrologic c...
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NASA Astrophysics Data System (ADS)
Troselj, Josko; Sayama, Takahiro; Varlamov, Sergey M.; Sasaki, Toshiharu; Racault, Marie-Fanny; Takara, Kaoru; Miyazawa, Yasumasa; Kuroki, Ryusuke; Yamagata, Toshio; Yamashiki, Yosuke
2017-12-01
This study demonstrates the importance of accurate extreme discharge input in hydrological and oceanographic combined modeling by introducing two extreme typhoon events. We investigated the effects of extreme freshwater outflow events from river mouths on sea surface salinity distribution (SSS) in the coastal zone of the north-eastern Japan. Previous studies have used observed discharge at the river mouth, as well as seasonally averaged inter-annual, annual, monthly or daily simulated data. Here, we reproduced the hourly peak discharge during two typhoon events for a targeted set of nine rivers and compared their impact on SSS in the coastal zone based on observed, climatological and simulated freshwater outflows in conjunction with verification of the results using satellite remote-sensing data. We created a set of hourly simulated freshwater outflow data from nine first-class Japanese river basins flowing to the western Pacific Ocean for the two targeted typhoon events (Chataan and Roke) and used it with the integrated hydrological (CDRMV3.1.1) and oceanographic (JCOPE-T) model, to compare the case using climatological mean monthly discharges as freshwater input from rivers with the case using our hydrological model simulated discharges. By using the CDRMV model optimized with the SCE-UA method, we successfully reproduced hindcasts for peak discharges of extreme typhoon events at the river mouths and could consider multiple river basin locations. Modeled SSS results were verified by comparison with Chlorophyll-a distribution, observed by satellite remote sensing. The projection of SSS in the coastal zone became more realistic than without including extreme freshwater outflow. These results suggest that our hydrological models with optimized model parameters calibrated to the Typhoon Roke and Chataan cases can be successfully used to predict runoff values from other extreme precipitation events with similar physical characteristics. Proper simulation of extreme typhoon events provides more realistic coastal SSS and may allow a different scenario analysis with various precipitation inputs for developing a nowcasting analysis in the future.
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Matamoros, Wilfredo A; Hoagstrom, Christopher W; Schaefer, Jacob F; Kreiser, Brian R
2016-08-01
Although the conterminous USA has a long history of ichthyological exploration, the description of biogeographical provinces has been ad hoc. In this study we quantitatively determined fish faunal provinces and interpreted them in the context of the geological history of North America. We also evaluated influences of major river basin occupancy and contemporary environmental factors on provincial patterns. Our data set comprised 794 native fishes, which we used to generate a presence and absence matrix for U.S. Geological Survey (USGS) four-digit hydrologic units. Three nested data sets were analysed separately: primary freshwater families, continental freshwater families (including primary and secondary families) and all freshwater families (including primary, secondary and peripheral families). We used clustering analysis to delimit faunal breaks and one-way analysis of similarity (ANOSIM) to determine significance among clusters (i.e. provinces). We used an indicator-species analysis to identify species that contributed most to province delineations and a similarity-percentage (SIMPER) analysis to describe the relative influence of representatives from each category (i.e. primary, secondary, peripheral) on provincial boundaries. Lastly, we used a parsimony redundancy analysis to determine the roles of historical (i.e. major river basin) and contemporary environmental factors in shaping provinces. Analysis of the nested data sets revealed lessening provincial structure with inclusion of more families. There were 10 primary freshwater provinces, 9 continental freshwater provinces and 7 all freshwater provinces. Major basin occupancy, but not contemporary environmental factors, explained substantial variance in faunal similarities among provinces. However, provincial boundaries did not conform strictly to modern river basins, but reflected river-drainage connections of the Quaternary. Provinces represent broad-scale patterns of endemism and provide a starting point for future studies. Relative malleability of province boundaries in the continental interior highlights this region as biogeographically diverse and dynamic. Interior-core provinces of this region (Central Gulf Coastal Plains, Northern Interior) have not been recognized previously and warrant further study. © 2015 Cambridge Philosophical Society.
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NASA Astrophysics Data System (ADS)
Eley, Malte; Schöniger, Hans Matthias; Gelleszun, Marlene; Wolf, Jens; Schneider, Anke; Wiederhold, Helga; Meon, Günter
2017-04-01
Especially coastal areas are vulnerable in case of sea level rise and changing climate conditions. Therefore, the NAWAK study (design of sustainable adaptation strategies for infrastructures in water management under the conditions of climatic and demographic change) started in 2013. It is designed to assess impairments of groundwater availability for a coastal lowland aquifer system in North-West Germany (> 1.000 km2) in the context of climate and socio-economic changes. The research results are focused on the quantification of the groundwater availability for past and future scenarios. Impacts from both climatic and socio-economic changes on the water availability and water balance are assessed by means of hydrologic, hydrogeological and geophysical models and methods, which where developed and adapted by project partners. For the model area there are three fields of work to create the conditions for a density dependent calculation of changings in salt-freshwater budget with the numerical model d3f++ (distributed density-driven Flow). The first is the description of initial conditions in three dimensions, especially for the salt-freshwater boundary. That description is based on airborne electromagnetic data of the underground and a complex processing to identify the differences between salt and freshwater, without anthropogenic and geologic influences. A validation is possible by comparison with groundwater measurements and an online monitoring of specific conductivity. The second is the calculation and measurement of flow conditions to derive the boundary conditions and the groundwater recharge. The groundwater recharge was calculated by using the hydrologic model PANTA RHEI. It is a conceptual model with partly physic-based modules, especially for the soil water processes. The model was calibrated and validated by discharge measurements and groundwater levels. The third step is a detailed information about the spatial discretization and the reconstruction of the geologic body. The interpolation of point information's from boreholes and geologic sections was calculated with the geologic modelling software SubsurfaceViewerMX. For implementation in the groundwater model, the layers were combined to hydrogeological similar units. With this sophisticated models it is possible to model the density-dependent complex groundwater systems at large spatial scales as well as contaminant transport. The modeling analysis is focused on water-budget components (groundwater recharge, submarine groundwater discharge, surface-groundwater interaction and water supply), salt- water intrusion and sea level rise under different climate and water-use scenarios. With our models we offer the capability to evaluate possible coastal aquifer management strategies of real-world applications.
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Salinity influences on aboveground and belowground net primary productivity in tidal wetlands
Pierfelice, Kathryn N.; Graeme Lockaby, B.; Krauss, Ken W.; Conner, William H.; Noe, Gregory; Ricker, Matthew C.
2017-01-01
Tidal freshwater wetlands are one of the most vulnerable ecosystems to climate change and rising sea levels. However salinification within these systems is poorly understood, therefore, productivity (litterfall, woody biomass, and fine roots) were investigated on three forested tidal wetlands [(1) freshwater, (2) moderately saline, and (3) heavily salt-impacted] and a marsh along the Waccamaw and Turkey Creek in South Carolina. Mean aboveground (litterfall and woody biomass) production on the freshwater, moderately saline, heavily salt-impacted, and marsh, respectively, was 1,061, 492, 79, and 0 g m−2 year−1 versus belowground (fine roots) 860, 490, 620, and 2,128 g m−2 year−1. Litterfall and woody biomass displayed an inverse relationship with salinity. Shifts in productivity across saline sites is of concern because sea level is predicted to continue rising. Results from the research reported in this paper provide baseline data upon which coupled hydrologic/wetland models can be created to quantify future changes in tidal forest functions.
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Microhabitat and biology of Sphaerium striatinum in a central New York stream
Dittman, Dawn E.; Johnson, James H.; Nack, Christopher C.
2018-01-01
In many lotic systems, drastic declines in freshwater bivalve populations, including fingernail clams (Sphaeriidae), have created concerns about biodiversity and future ecosystem services. We examined the local occurrence of the historically common fingernail clam, Sphaerium striatinum, in a central New York stream. We sampled the density of sphaeriids and measured the associated habitat variables (substrate, depth, water flow) to test within-stream multivariate benthic microhabitat association. Size distribution, density, and diel feeding periodicity were measured as focal aspects of fingernail clam biology and ecology. S. striatinum tended to be found in microhabitats that had harder substrates and faster flow. The Labrador Creek fingernail clam local population had positive indicators (size distribution, density). There was significant diel periodicity in feeding behavior. The clams fed most actively during the 0400–0800 h periods. This kind of behavioral periodicity can indicate a significant ecological interaction between predators and bivalve prey. Increased understanding of the behavioral ecology of small native freshwater bivalves in an unimpacted headwater stream is a fundamental building block for development of overall ecological conservation goals for freshwater bivalves and their lotic habitats.
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Freshwater fluxes in the Weddell Gyre: results from δ18O
Brown, Peter J.; Meredith, Michael P.; Jullion, Loïc; Naveira Garabato, Alberto; Torres-Valdés, Sinhue; Holland, Paul; Leng, Melanie J.; Venables, Hugh
2014-01-01
Full-depth measurements of δ18O from 2008 to 2010 enclosing the Weddell Gyre in the Southern Ocean are used to investigate the regional freshwater budget. Using complementary salinity, nutrients and oxygen data, a four-component mass balance was applied to quantify the relative contributions of meteoric water (precipitation/glacial input), sea-ice melt and saline (oceanic) sources. Combination of freshwater fractions with velocity fields derived from a box inverse analysis enabled the estimation of gyre-scale budgets of both freshwater types, with deep water exports found to dominate the budget. Surface net sea-ice melt and meteoric contributions reach 1.8% and 3.2%, respectively, influenced by the summer sampling period, and −1.7% and +1.7% at depth, indicative of a dominance of sea-ice production over melt and a sizable contribution of shelf waters to deep water mass formation. A net meteoric water export of approximately 37 mSv is determined, commensurate with local estimates of ice sheet outflow and precipitation, and the Weddell Gyre is estimated to be a region of net sea-ice production. These results constitute the first synoptic benchmarking of sea-ice and meteoric exports from the Weddell Gyre, against which future change associated with an accelerating hydrological cycle, ocean climate change and evolving Antarctic glacial mass balance can be determined. PMID:24891394
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Methane Feedbacks to the Global Climate System in a Warmer World
NASA Astrophysics Data System (ADS)
Dean, Joshua F.; Middelburg, Jack J.; Röckmann, Thomas; Aerts, Rien; Blauw, Luke G.; Egger, Matthias; Jetten, Mike S. M.; de Jong, Anniek E. E.; Meisel, Ove H.; Rasigraf, Olivia; Slomp, Caroline P.; in't Zandt, Michiel H.; Dolman, A. J.
2018-03-01
Methane (CH4) is produced in many natural systems that are vulnerable to change under a warming climate, yet current CH4 budgets, as well as future shifts in CH4 emissions, have high uncertainties. Climate change has the potential to increase CH4 emissions from critical systems such as wetlands, marine and freshwater systems, permafrost, and methane hydrates, through shifts in temperature, hydrology, vegetation, landscape disturbance, and sea level rise. Increased CH4 emissions from these systems would in turn induce further climate change, resulting in a positive climate feedback. Here we synthesize biological, geochemical, and physically focused CH4 climate feedback literature, bringing together the key findings of these disciplines. We discuss environment-specific feedback processes, including the microbial, physical, and geochemical interlinkages and the timescales on which they operate, and present the current state of knowledge of CH4 climate feedbacks in the immediate and distant future. The important linkages between microbial activity and climate warming are discussed with the aim to better constrain the sensitivity of the CH4 cycle to future climate predictions. We determine that wetlands will form the majority of the CH4 climate feedback up to 2100. Beyond this timescale, CH4 emissions from marine and freshwater systems and permafrost environments could become more important. Significant CH4 emissions to the atmosphere from the dissociation of methane hydrates are not expected in the near future. Our key findings highlight the importance of quantifying whether CH4 consumption can counterbalance CH4 production under future climate scenarios.
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Salmon runs have declined over the past two centuries in the Pacific Northwest region of North America. Reduced inputs of salmon-derived organic matter and nutrients (SDN) may limit freshwater production and thus establish a negative feedback loop affecting future generations of...
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Regulation of snow-fed rivers affects flow regimes more than climate change.
Arheimer, B; Donnelly, C; Lindström, G
2017-07-05
River flow is mainly controlled by climate, physiography and regulations, but their relative importance over large landmasses is poorly understood. Here we show from computational modelling that hydropower regulation is a key driver of flow regime change in snow-dominated regions and is more important than future climate changes. This implies that climate adaptation needs to include regulation schemes. The natural river regime in snowy regions has low flow when snow is stored and a pronounced peak flow when snow is melting. Global warming and hydropower regulation change this temporal pattern similarly, causing less difference in river flow between seasons. We conclude that in snow-fed rivers globally, the future climate change impact on flow regime is minor compared to regulation downstream of large reservoirs, and of similar magnitude over large landmasses. Our study not only highlights the impact of hydropower production but also that river regulation could be turned into a measure for climate adaptation to maintain biodiversity on floodplains under climate change.Global warming and hydropower regulations are major threats to future fresh-water availability and biodiversity. Here, the authors show that their impact on flow regime over a large landmass result in similar changes, but hydropower is more critical locally and may have potential for climate adaptation in floodplains.
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Huff, G.F.
2004-01-01
Increasing demand on the limited supplies of freshwater in the desert Southwest, as well as other parts of the United States, has increased the level of interest in saline-water resources. Saline ground water has long been recognized as a potentially important contributor to water supply in the Southwest, as demonstrated by the number of hydrologic, geologic, and engineering studies on the distribution of saline water and the feasibility of desalination. Potential future study needs include investigating and documenting the three-dimensional distribution of salinity and chemical composition of saline-water resources and the hydraulic properties of aquifers containing these saline-water resources, assessing the chemical suitability of saline water for use with existing and anticipated desalination technologies, simulating the effect of withdrawal of saline ground water on water levels and water composition in saline and adjoining or overlying freshwater aquifers, and determining the suitability of target geologic formations for injection of desalination-generated waste.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Wilson, Wayne H.; Schricker, Jaym'e; Ruzychi, James R.
The John Day River subbasin supports one of the last remaining intact wild populations of spring Chinook salmon and summer steelhead in the Columbia River Basin. These populations remain depressed relative to historic levels and limited information is available for steelhead life history. Numerous habitat protection and rehabilitation projects have been implemented in the basin to improve salmonid freshwater production and survival. However, these projects often lack effectiveness monitoring. While our monitoring efforts outlined here will not specifically measure the effectiveness of any particular project, they will provide much needed programmatic or watershed (status and trend) information to help evaluatemore » project-specific effectiveness monitoring efforts as well as meet some data needs as index stocks. Our continued monitoring efforts to estimate salmonid smolt abundance, age structure, SAR, smolts/redd, freshwater habitat use, and distribution of critical life states will enable managers to assess the long-term effectiveness of habitat projects and to differentiate freshwater and ocean survival. Because Columbia Basin managers have identified the John Day subbasin spring Chinook population as an index population for assessing the effects of alternative future management actions on salmon stocks in the Columbia Basin (Schaller et al. 1999) we continue our ongoing studies. This project is high priority based on the level of emphasis by the NWPPC Fish and Wildlife Program, Independent Scientific Advisory Board (ISAB), Independent Scientific Review Panel (ISRP), NOAA National Marine Fisheries Service (NMFS), and the Oregon Plan for Salmon and Watersheds (OWEB). Each of these groups have placed priority on monitoring and evaluation to provide the real-time data to guide restoration and adaptive management in the region. The objective is to estimate smolt-to-adult survival rates (SAR) and out-migrant abundance for spring Chinook Oncorhynchus tshawytscha and summer steelhead O. mykiss and life history characteristics of summer steelhead.« less
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The Hydrological Response of Snowmelt Dominated Catchments to Climate Change
NASA Astrophysics Data System (ADS)
Arrigoni, A. S.; Moore, J. N.
2007-12-01
Hydrological systems dominated by snowmelt discharge contribute greater than half the freshwater resource available to the western United States. Globally, the contribution of mountain discharge to total runoff is twice the expected for their geographical coverage. Therefore, snowmelt dominated mountain catchments have proportionally a more prominent role than other systems to our freshwater resource. A changing climate, or even a more variable climate, could have a significant impact on these systems, and consequently on our freshwater resource. Ergo, a better understanding of how changes and variations in climate will influence mountain catchments is a necessity for improving future water management under predicted/proposed climate change. The research presented here is a first order analysis to improve our understanding of these systems by monitoring and analyzing high mountain catchments along the entirety of the Mission Mountain Front, Montana USA. The Mission Mountain Range is an ideal location for conducting this research as it runs directly north to south with elevations progressively increasing from 7600 feet in the northern section, to over 9700 feet at the southern end. The lower elevation catchments will be used as surrogates for variable climate change, while the high elevation catchments will be used as surrogates for a more stable, cooler, climate regime. We use a combination of USGS and Tribal stream gauges, as well as stage gauge loggers in the headwaters of the catchments, SNOTEL datasets, and weather station datasets. This information is used to determine if, how, and why the snowmelt hydrographs vary between catchments, within the catchments between the upper and lower segments, and the dominant driver or drivers of the hydrograph form in relation to changing climatic variables such as temperature and precipitation. This research will improve current comprehension of how mountain catchments respond to climatic variables, and additionally will expand upon the current understanding of general catchment hydrology.
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NASA Astrophysics Data System (ADS)
Basu, N. B.; Van Meter, K. J.; Tate, E.
2012-12-01
In semi-arid to arid landscapes under intensive irrigation, groundwater salinization can be a persistent and critical problem, leading to reduced agricultural productivity, limited access to fresh drinking water, and ultimately desertification. It is estimated that in India alone, problems of salinity are now affecting over 6 million hectares of agricultural land. In villages of the Mewat district of Haryana in Northern India, subsistence-level farming is the primary source of income, and farming families live under serious threat from increasing salinity levels, both in terms of crop production and adequate supplies of drinking water. The Institute for Rural Research and Development (IRRAD), a non-governmental organization (NGO) working in Mewat, has taken an innovative approach in this area to problems of groundwater salinization, using check dams and rainwater harvesting ponds to recharge aquifers in the freshwater zones of upstream hill areas, and to create freshwater pockets within the saline groundwater zones of down-gradient areas. Initial, pilot-scale efforts have led to apparent success in raising groundwater levels in freshwater zones and changing the dynamics of encroaching groundwater salinity, but the expansion of such efforts to larger-scale restoration is constrained by the availability of adequate resources. Under such resource constraints, which are typical of international development work, it becomes critical to utilize a decision-analysis framework to quantify both the immediate and long-term effectiveness and sustainability of interventions by NGOs such as IRRAD. In the present study, we have developed such a framework, linking the climate-hydrological dynamics of monsoon driven systems with village-scale socio-economic attributes to evaluate the sustainability of current restoration efforts and to prioritize future areas for intervention. We utilize a multi-dimensional metric that takes into account both physical factors related to water availability as well as socio-economic factors related to the capacity to deal with water stress. This metric allows us to evaluate and compare water-driven sustainability at the village, block, and district levels in Northern India based on a combination of readily available census and water resource data. Further, we utilize a pressure-response framework that considers monsoonal dynamics and effectively evaluates the effects of intervention efforts over time. Our results indicate that in arid to semi-arid regions, where problems of groundwater salinity are paramount, scaling factors corresponding to salinity levels as well as the relative size of the saline zone must be incorporated into indicators of water access and availability to accurately reflect overall sustainability. More importantly, the results point towards the value of incorporating dynamic, multi-dimensional sustainability metrics into decision-analysis frameworks used to aid in resource prioritization and the evaluation of intervention efforts.
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Magnetic resonance imaging of live freshwater mussels (Unionidae)
Michael, Holliman F.; Davis, Denise; Bogan, Arthur E.; Kwak, Thomas J.; Cope, W. Gregory; Levine, Jay F.
2008-01-01
We examined the soft tissues of live freshwater mussels, Eastern elliptio Elliptio complanata, via magnetic resonance imaging (MRI), acquiring data with a widely available human whole-body MRI system. Anatomical features depicted in the profile images included the foot, stomach, intestine, anterior and posterior adductor muscles, and pericardial cavity. Noteworthy observations on soft tissue morphology included a concentration of lipids at the most posterior aspect of the foot, the presence of hemolymph-filled fissures in the posterior adductor muscle, the presence of a relatively large hemolymph-filled sinus adjacent to the posterior adductor muscle (at the ventral-anterior aspect), and segmentation of the intestine (a diagnostic description not reported previously in Unionidae). Relatively little is known about the basic biology and ecological physiology of freshwater mussels. Traditional approaches for studying anatomy and tissue processes, and for measuring sub-lethal physiological stress, are destructive or invasive. Our study, the first to evaluate freshwater mussel soft tissues by MRI, clarifies the body plan of unionid mussels and demonstrates the efficacy of this technology for in vivoevaluation of the structure, function, and integrity of mussel soft tissues.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Reddy, S.L.N.; Venugopal, N.B.R.K.; Ramana Rao, J.V.
1989-06-01
Cadmium is a toxic, non-essential heavy metal inhibiting numerous enzymes with functional sulfhydryl groups. Among the animals, aquatic organisms are most sensitive to heavy metals. Various aspects of toxic effects of cadmium pollution on fishes have been extensively reviewed. Survey of literature reveals that relatively few attempts have been made on the various aspects of cadmium toxicity in crustaceans and these studies were mainly devoted to marine forms. The freshwater crustaceans, particularly the freshwater field crab, Barytelphusa guerini, received less attention. This crab forms one of the major components of the paddy field ecosystem and has an edible importance amongmore » local populations. Apart from this, these crabs are easily available, maintainable in the laboratory and data obtained in this study can be extrapolated to other crustaceans. The present study reports the influence of cadmium on certain aspects of carbohydrate metabolism in the tissues of the freshwater field crab, Barytelphusa guerini, exposed to sublethal concentration of cadmium chloride.« less
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Kang, Sung-Ryong; King, Sammy L.
2012-01-01
Salinization of coastal freshwater environments is a global issue. Increased salinity from sea level rise, storm surges, or other mechanisms is common in coastal freshwater marshes of Louisiana, USA. The effects of salinity increases on aquatic macroinvertebrates in these systems have received little attention, despite the importance of aquatic macroinvertebrates for nutrient cycling, biodiversity, and as a food source for vertebrate species. We used microcosm experiments to evaluate the effects of salinity, duration of exposure, and prey availability on the relative survival of dominant aquatic macroinvertebrates (i.e., Procambarus clarkii Girard, Cambarellus puer Hobbs, Libellulidae, Dytiscidae cybister) in a freshwater marsh of southwestern Louisiana. We hypothesized that increased salinity, absence of prey, and increased duration of exposure would decrease survival of aquatic macroinvertebrates and that crustaceans would have higher survival than aquatic insect taxon. Our first hypothesis was only partially supported as only salinity increases combined with prolonged exposure duration affected aquatic macroinvertebrate survival. Furthermore, crustaceans had higher survival than aquatic insects. Salinity stress may cause mortality when acting together with other stressful conditions.
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Siderophores: The special ingredient to cyanobacterial blooms
NASA Astrophysics Data System (ADS)
Du, Xue; Creed, Irena; Trick, Charles
2013-04-01
Freshwater lakes provide a number of significant ecological services including clean drinking water, habitat for aquatic biota, and economic benefits. The provision of these ecological services, as well as the health of these aquatic systems, is threatened by the excessive growth of algae, specifically, cyanobacteria. Historically, blooms have been linked to eutrophication but recent occurrences indicate that there are less dramatic changes that induce these blooms. Iron is an essential micronutrient required for specific essential metabolic pathways; however, the amount of biologically available iron in naturally occurring lake ranges from saturation to much lower than cell transport affinities. To assist in the modulation of iron availabilities, cyanobacteria in culture produce low molecular weight compounds that function in an iron binding and acquisition system; nevertheless, this has yet to be confirmed in naturally occurring lakes. This project explored the relationship of P, N and in particular, Fe, in the promotion of cyanobacteria harmful algal blooms in 30 natural freshwater lakes located in and around the Elk Island National Park, Alberta. It is hypothesized that cyanobacteria produce and utilize iron chelators called siderophores in low Fe and nitrogen (N) conditions, creating a competitive advantage over other algae in freshwater lakes. Lakes were selected to represent a range of iron availability to explore the nutrient composition of lakes that propagated cyanobacteria harmful algal blooms (cHABs) compared to lakes that did not. Lake water was analyzed for nutrients, microbial composition, siderophore concentration, and toxin concentration. Modifications were made to optimize the Czaky and Arnow tests for hydroxamate- and catecholate-type siderophores, respectively, for field conditions. Preliminary results indicate the presence of iron-binding ligands (0.11-2.34 mg/L) in freshwater lakes characterized by widely ranging Fe regimes (0.04-2.74 mg/L). Furthermore, the concentration of iron-binding ligands was found to have a positive correlation to presence of cyanobacteria concentration, indicating a potential relationship between Fe, siderophores, and cyanobacteria. This project works to improve the understanding of freshwater cyanobacteria growth dynamics by investigating the physiological and biochemical processes leading to cHABs. The importance of this project lies in the understanding of elementary nutrient requirements in all algae and how cyanobacteria are able to access low concentration pools and subsequently bloom over other algal species. Investigating the nutrient regimes that stimulate siderophore production and the subsequent production of potentially toxic cyanobacteria blooms is important for lake management and preservation, specifically in the eutrophic and hypereutrophic freshwater lakes of Alberta.
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Continental-scale assessment of risk to the Australian odonata from climate change.
Bush, Alex A; Nipperess, David A; Duursma, Daisy E; Theischinger, Gunther; Turak, Eren; Hughes, Lesley
2014-01-01
Climate change is expected to have substantial impacts on the composition of freshwater communities, and many species are threatened by the loss of climatically suitable habitat. In this study we identify Australian Odonata (dragonflies and damselflies) vulnerable to the effects of climate change on the basis of exposure, sensitivity and pressure to disperse in the future. We used an ensemble of species distribution models to predict the distribution of 270 (85%) species of Australian Odonata, continent-wide at the subcatchment scale, and for both current and future climates using two emissions scenarios each for 2055 and 2085. Exposure was scored according to the departure of temperature, precipitation and hydrology from current conditions. Sensitivity accounted for change in the area and suitability of projected climatic habitat, and pressure to disperse combined measurements of average habitat shifts and the loss experienced with lower dispersal rates. Streams and rivers important to future conservation efforts were identified based on the sensitivity-weighted sum of habitat suitability for the most vulnerable species. The overall extent of suitable habitat declined for 56-69% of the species modelled by 2085 depending on emissions scenario. The proportion of species at risk across all components (exposure, sensitivity, pressure to disperse) varied between 7 and 17% from 2055 to 2085 and a further 3-17% of species were also projected to be at high risk due to declines that did not require range shifts. If dispersal to Tasmania was limited, many south-eastern species are at significantly increased risk. Conservation efforts will need to focus on creating and preserving freshwater refugia as part of a broader conservation strategy that improves connectivity and promotes adaptive range shifts. The significant predicted shifts in suitable habitat could potentially exceed the dispersal capacity of Odonata and highlights the challenge faced by other freshwater species.
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Continental-Scale Assessment of Risk to the Australian Odonata from Climate Change
Bush, Alex A.; Nipperess, David A.; Duursma, Daisy E.; Theischinger, Gunther; Turak, Eren; Hughes, Lesley
2014-01-01
Climate change is expected to have substantial impacts on the composition of freshwater communities, and many species are threatened by the loss of climatically suitable habitat. In this study we identify Australian Odonata (dragonflies and damselflies) vulnerable to the effects of climate change on the basis of exposure, sensitivity and pressure to disperse in the future. We used an ensemble of species distribution models to predict the distribution of 270 (85%) species of Australian Odonata, continent-wide at the subcatchment scale, and for both current and future climates using two emissions scenarios each for 2055 and 2085. Exposure was scored according to the departure of temperature, precipitation and hydrology from current conditions. Sensitivity accounted for change in the area and suitability of projected climatic habitat, and pressure to disperse combined measurements of average habitat shifts and the loss experienced with lower dispersal rates. Streams and rivers important to future conservation efforts were identified based on the sensitivity-weighted sum of habitat suitability for the most vulnerable species. The overall extent of suitable habitat declined for 56–69% of the species modelled by 2085 depending on emissions scenario. The proportion of species at risk across all components (exposure, sensitivity, pressure to disperse) varied between 7 and 17% from 2055 to 2085 and a further 3–17% of species were also projected to be at high risk due to declines that did not require range shifts. If dispersal to Tasmania was limited, many south-eastern species are at significantly increased risk. Conservation efforts will need to focus on creating and preserving freshwater refugia as part of a broader conservation strategy that improves connectivity and promotes adaptive range shifts. The significant predicted shifts in suitable habitat could potentially exceed the dispersal capacity of Odonata and highlights the challenge faced by other freshwater species. PMID:24551197
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Park, Jong-Hwan; Wang, Jim J; Xiao, Ran; Pensky, Scott M; Kongchum, Manoch; DeLaune, Ronald D; Seo, Dong-Cheol
2018-03-01
Mercury adsorption characteristics of Mississippi River deltaic plain (MRDP) freshwater marsh soil in the Louisiana Gulf coast were evaluated under various conditions. Mercury adsorption was well described by pseudo-second order and Langmuir isotherm models with maximum adsorption capacity of 39.8 mg g -1 . Additional fitting of intraparticle model showed that mercury in the MRDP freshwater marsh soil was controlled by both external surface adsorption and intraparticle diffusion. The partition of adsorbed mercury (mg g -1 ) revealed that mercury was primarily adsorbed into organic-bond fraction (12.09) and soluble/exchangeable fraction (10.85), which accounted for 63.5% of the total adsorption, followed by manganese oxide-bound (7.50), easily mobilizable carbonate-bound (4.53), amorphous iron oxide-bound (0.55), crystalline Fe oxide-bound (0.41), and residual fraction (0.16). Mercury adsorption capacity was generally elevated along with increasing solution pH even though dominant species of mercury were non-ionic HgCl 2 , HgClOH and Hg(OH) 2 at between pH 3 and 9. In addition, increasing background NaCl concentration and the presence of humic acid decreased mercury adsorption, whereas the presence of phosphate, sulfate and nitrate enhanced mercury adsorption. Mercury adsorption in the MRDP freshwater marsh soil was reduced by the presence of Pb, Cu, Cd and Zn with Pb showing the greatest competitive adsorption. Overall the adsorption capacity of mercury in the MRDP freshwater marsh soil was found to be significantly influenced by potential environmental changes, and such factors should be considered in order to manage the risks associated with mercury in this MRDP wetland for responding to future climate change scenarios. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Abdel-Gaber, Rewaida; Fol, Mona; Al Quraishy, Saleh
2018-05-08
Water mites of the genus Unionicola are the most common symbionts of freshwater bivalves. During the current investigation, a total of 120 live freshwater mussels [Corbicula fluminea (Veneroida), Coelatura aegyptiaca (Unionoidea) Mutela rostrata and Chambardia rubens (Mutelidae)], were collected from 2 localities in Tura (Helwan Governorate) and El Kanater (Qaluobiya Governorate), Egypt. Only 3 of the 4 bivalve species listed are considered freshwater bivalves (members of Unionoidea). While, C. fluminea belong to the family Cyrenidae within Veneroida. The collected mussels were dissected and examined for the presence of unionicolid mites. It was found that 30.83% (37/120) were infected with a single mite species Unionicola tetrafurcatus (Unionicolidae). The highest prevalence was observed during the summer with 83.33% (25/30), whereas the least was observed in autumn, i.e. 33.33% (10/30). Mites were recovered from the gills, gonads, and visceral mass of mussel hosts. gills of host mussels were the primary site of oviposition for unionicola mites. Smaller bivalves in size had significantly greater numbers of mites than larger ones in size. Numbers of mites per host species was variable and the highest prevalence level of 83.33% (25/30) was recorded in C. fluminea, while, the lowest one of 16.66% (5/30) was found in C. rubens. Morphological and morphometric characterizations of mites revealed some differences between the present species and other related Unionicola. Histopathological responses of host mussels to the eggs, larvae, and cuticular remnants of U. tetrafurcatus were also studied. Therefore, the present study demonstrated that freshwater bivalves have a new host and locality records for infection with U. tetrafurcatus. Future studies are recommended to include advanced molecular characteristics for these mites.
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Hawaiian Goose (Branta sandvicensis)
Banko, Paul C.; Black, Jeffrey M.; Banko, Winston E.
1999-01-01
Evolving in the remote Hawaiian Archipelago and having the smallest range of any living goose, the Hawaiian Goose, or better known by its Hawaiian name—Nënë, is among the most isolated, sedentary, and threatened of waterfowl. The Nënë is also highly terrestrial, and several structural features demonstrate its adaptation to life on islands with limited freshwater habitat: It stands taller and more upright than geese of similar weight, enabling it to reach high to browse the fruits, seeds, and foliage that constitute its herbivorous diet; its legs and padded toes are long and strong, promoting swift, sure walking and running over rugged terrain; webbing is reduced between the toes; and though it is a capable swimmer and readily uses freshwater habitats when available, the Nënë does not require freshwater or oceanic habitats in the same way that many other waterfowl do.
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Knowles, Noah
2002-01-01
Understanding the processes controlling the physics, chemistry, and biology of the San Francisco Estuary and their relation to climate variability is complicated by the combined influence on freshwater inflows of natural variability and upstream management. To distinguish these influences, alterations of estuarine inflow due to major reservoirs and freshwater pumping in the watershed were inferred from available data. Effects on salinity were estimated by using reconstructed estuarine inflows corresponding to differing levels of impairment to drive a numerical salinity model. Both natural and management inflow and salinity signals show strong interannual variability. Management effects raise salinities during the wet season, with maximum influence in spring. While year‐to‐year variations in all signals are very large, natural interannual variability can greatly exceed the range of management effects on salinity in the estuary.
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Consequences of rapid ice sheet melting on the Sahelian population vulnerability
Ramstein, Gilles; Charbit, Sylvie; Vrac, Mathieu; Famien, Adjoua Moïse; Sultan, Benjamin; Swingedouw, Didier; Dumas, Christophe; Gemenne, François; Alvarez-Solas, Jorge; Vanderlinden, Jean-Paul
2017-01-01
The acceleration of ice sheet melting has been observed over the last few decades. Recent observations and modeling studies have suggested that the ice sheet contribution to future sea level rise could have been underestimated in the latest Intergovernmental Panel on Climate Change report. The ensuing freshwater discharge coming from ice sheets could have significant impacts on global climate, and especially on the vulnerable tropical areas. During the last glacial/deglacial period, megadrought episodes were observed in the Sahel region at the time of massive iceberg surges, leading to large freshwater discharges. In the future, such episodes have the potential to induce a drastic destabilization of the Sahelian agroecosystem. Using a climate modeling approach, we investigate this issue by superimposing on the Representative Concentration Pathways 8.5 (RCP8.5) baseline experiment a Greenland flash melting scenario corresponding to an additional sea level rise ranging from 0.5 m to 3 m. Our model response to freshwater discharge coming from Greenland melting reveals a significant decrease of the West African monsoon rainfall, leading to changes in agricultural practices. Combined with a strong population increase, described by different demography projections, important human migration flows could be potentially induced. We estimate that, without any adaptation measures, tens to hundreds million people could be forced to leave the Sahel by the end of this century. On top of this quantification, the sea level rise impact over coastal areas has to be superimposed, implying that the Sahel population could be strongly at threat in case of rapid Greenland melting. PMID:28584113
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Misut, Paul; Aphale, Omkar
2014-01-01
A density-dependent groundwater flow and solute transport model of Manhasset Neck, Long Island, New York, was used to analyze (1) the effects of seasonal stress on the position of the freshwater/saltwater transition zone and (2) groundwater flowpaths. The following were used in the simulation: 182 transient stress periods, representing the historical record from 1920 to 2011, and 44 transient stress periods, representing future hypothetical conditions from 2011 to 2030. Simulated water-level and salinity (chloride concentration) values are compared with values from a previously developed two-stress-period (1905–1944 and 1945–2005) model. The 182-stress-period model produced salinity (chloride concentration) values that more accurately matched the observed salinity (chloride concentration) values in response to hydrologic stress than did the two-stress-period model, and salinity ranged from zero to about 3 parts per thousand (equivalent to zero to 1,660 milligrams per liter chloride). The 182-stress-period model produced improved calibration statistics of water-level measurements made throughout the study area than did the two-stress-period model, reducing the Lloyd aquifer root mean square error from 7.0 to 5.2 feet. Decreasing horizontal and vertical hydraulic conductivities (fixed anisotropy ratio) of the Lloyd and North Shore aquifers by 20 percent resulted in nearly doubling the simulated salinity(chloride concentration) increase at Port Washington observation well N12508. Groundwater flowpath analysis was completed for 24 production wells to delineate water source areas. The freshwater/saltwater transition zone moved toward and(or) away from wells during future hypothetical scenarios.
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Consequences of rapid ice sheet melting on the Sahelian population vulnerability.
Defrance, Dimitri; Ramstein, Gilles; Charbit, Sylvie; Vrac, Mathieu; Famien, Adjoua Moïse; Sultan, Benjamin; Swingedouw, Didier; Dumas, Christophe; Gemenne, François; Alvarez-Solas, Jorge; Vanderlinden, Jean-Paul
2017-06-20
The acceleration of ice sheet melting has been observed over the last few decades. Recent observations and modeling studies have suggested that the ice sheet contribution to future sea level rise could have been underestimated in the latest Intergovernmental Panel on Climate Change report. The ensuing freshwater discharge coming from ice sheets could have significant impacts on global climate, and especially on the vulnerable tropical areas. During the last glacial/deglacial period, megadrought episodes were observed in the Sahel region at the time of massive iceberg surges, leading to large freshwater discharges. In the future, such episodes have the potential to induce a drastic destabilization of the Sahelian agroecosystem. Using a climate modeling approach, we investigate this issue by superimposing on the Representative Concentration Pathways 8.5 (RCP8.5) baseline experiment a Greenland flash melting scenario corresponding to an additional sea level rise ranging from 0.5 m to 3 m. Our model response to freshwater discharge coming from Greenland melting reveals a significant decrease of the West African monsoon rainfall, leading to changes in agricultural practices. Combined with a strong population increase, described by different demography projections, important human migration flows could be potentially induced. We estimate that, without any adaptation measures, tens to hundreds million people could be forced to leave the Sahel by the end of this century. On top of this quantification, the sea level rise impact over coastal areas has to be superimposed, implying that the Sahel population could be strongly at threat in case of rapid Greenland melting.
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Kummu, M; Guillaume, J H A; de Moel, H; Eisner, S; Flörke, M; Porkka, M; Siebert, S; Veldkamp, T I E; Ward, P J
2016-12-09
Water scarcity is a rapidly growing concern around the globe, but little is known about how it has developed over time. This study provides a first assessment of continuous sub-national trajectories of blue water consumption, renewable freshwater availability, and water scarcity for the entire 20 th century. Water scarcity is analysed using the fundamental concepts of shortage (impacts due to low availability per capita) and stress (impacts due to high consumption relative to availability) which indicate difficulties in satisfying the needs of a population and overuse of resources respectively. While water consumption increased fourfold within the study period, the population under water scarcity increased from 0.24 billion (14% of global population) in the 1900s to 3.8 billion (58%) in the 2000s. Nearly all sub-national trajectories show an increasing trend in water scarcity. The concept of scarcity trajectory archetypes and shapes is introduced to characterize the historical development of water scarcity and suggest measures for alleviating water scarcity and increasing sustainability. Linking the scarcity trajectories to other datasets may help further deepen understanding of how trajectories relate to historical and future drivers, and hence help tackle these evolving challenges.
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Kummu, M.; Guillaume, J. H. A.; de Moel, H.; Eisner, S.; Flörke, M.; Porkka, M.; Siebert, S.; Veldkamp, T. I. E.; Ward, P. J.
2016-01-01
Water scarcity is a rapidly growing concern around the globe, but little is known about how it has developed over time. This study provides a first assessment of continuous sub-national trajectories of blue water consumption, renewable freshwater availability, and water scarcity for the entire 20th century. Water scarcity is analysed using the fundamental concepts of shortage (impacts due to low availability per capita) and stress (impacts due to high consumption relative to availability) which indicate difficulties in satisfying the needs of a population and overuse of resources respectively. While water consumption increased fourfold within the study period, the population under water scarcity increased from 0.24 billion (14% of global population) in the 1900s to 3.8 billion (58%) in the 2000s. Nearly all sub-national trajectories show an increasing trend in water scarcity. The concept of scarcity trajectory archetypes and shapes is introduced to characterize the historical development of water scarcity and suggest measures for alleviating water scarcity and increasing sustainability. Linking the scarcity trajectories to other datasets may help further deepen understanding of how trajectories relate to historical and future drivers, and hence help tackle these evolving challenges. PMID:27934888
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Blue water tradeoffs with ecosystems in a CO2-enriched climate
NASA Astrophysics Data System (ADS)
Mankin, J. S.; Smerdon, J. E.; Cook, B. I.; Williams, A. P.; Seager, R.
2017-12-01
Present and future freshwater availability and drought risks are physically tied to the competing responses of surface vegetation to increasing CO2, which includes radiative and plant physiological forcing, as well as their consequences for plant phenology, water use efficiency, and CO2 fertilization. Because Earth system models (ESMs) have increased their sophistication in representing the coupling among biogeochemical and biogeophysical processes at the land surface, projected linkages among ecosystem responses to CO2 and blue water (runoff) can be explored. A detailed analysis of the Western US demonstrates that CO2- and radiatively-induced vegetation growth drives projected decreases in soil moisture and runoff in the NCAR CESM LENS, creating a curious pattern of colocated 'greening' and 'drying.' Here we explore these responses at the global-scale and the consequences of such vegetation-driven drying on blue water availability for people. We present a simple metric that quantifies the tradeoff that occurs between ecosystems and blue water and link their occurrence to changes in daily-scale precipitation extremes, plant functional types, and changes in leaf areas. These results have implications for blue water availability for people and raise important questions about model representations of vegetation-water responses to high CO2.
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Long-term ice phenology records from eastern-central Europe
NASA Astrophysics Data System (ADS)
Takács, Katalin; Kern, Zoltán; Pásztor, László
2018-03-01
A dataset of annual freshwater ice phenology was compiled for the largest river (Danube) and the largest lake (Lake Balaton) in eastern-central Europe, extending regular river and lake ice monitoring data through the use of historical observations and documentary records dating back to AD 1774 and AD 1885, respectively. What becomes clear is that the dates of the first appearance of ice and freeze-up have shifted, arriving 12-30 and 4-13 days later, respectively, per 100 years. Break-up and ice-off have shifted to earlier dates by 7-13 and 9-27 days/100 years, except on Lake Balaton, where the date of break-up has not changed significantly. The datasets represent a resource for (paleo)climatological research thanks to the strong, physically determined link between water and air temperature and the occurrence of freshwater ice phenomena. The derived centennial records of freshwater cryophenology for the Danube and Balaton are readily available for detailed analysis of the temporal trends, large-scale spatial comparison, or other climatological purposes. The derived dataset is publicly available via PANGAEA at https://doi.org/10.1594/PANGAEA.881056.
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Environmental heterogeneity predicts species richness of freshwater mollusks in sub-Saharan Africa
NASA Astrophysics Data System (ADS)
Hauffe, T.; Schultheiß, R.; Van Bocxlaer, B.; Prömmel, K.; Albrecht, C.
2016-09-01
Species diversity and how it is structured on a continental scale is influenced by stochastic, ecological, and evolutionary driving forces, but hypotheses on determining factors have been mainly examined for terrestrial and marine organisms. The extant diversity of African freshwater mollusks is in general well assessed to facilitate conservation strategies and because of the medical importance of several taxa as intermediate hosts for tropical parasites. This historical accumulation of knowledge has, however, not resulted in substantial macroecological studies on the spatial distribution of freshwater mollusks. Here, we use continental distribution data and a recently developed method of random and cohesive allocation of species distribution ranges to test the relative importance of various factors in shaping species richness of Bivalvia and Gastropoda. We show that the mid-domain effect, that is, a hump-shaped richness gradient in a geographically bounded system despite the absence of environmental gradients, plays a minor role in determining species richness of freshwater mollusks in sub-Saharan Africa. The western branch of the East African Rift System was included as dispersal barrier in richness models, but these simulation results did not fit observed diversity patterns significantly better than models where this effect was not included, which suggests that the rift has played a more complex role in generating diversity patterns. Present-day precipitation and temperature explain richness patterns better than Eemian climatic condition. Therefore, the availability of water and energy for primary productivity during the past does not influence current species richness patterns much, and observed diversity patterns appear to be in equilibrium with contemporary climate. The availability of surface waters was the best predictor of bivalve and gastropod richness. Our data indicate that habitat diversity causes the observed species-area relationship, and hence, that environmental heterogeneity is a principal driver of freshwater mollusk richness on a continental scale.
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Eutrophication of freshwater and marine ecosystems
Smith, Val H.; Joye, Samantha B.; Howarth, Robert W.
2006-01-01
Initial understanding of the links between nutrients and aquatic productivity originated in Europe in the early 1900s, and our knowledge base has expanded greatly during the past 40 yr. This explosion of eutrophication-related research has made it unequivocally clear that a comprehensive strategy to prevent excessive amounts of nitrogen and phosphorus from entering our waterways is needed to protect our lakes, rivers, and coasts from water quality deterioration. However, despite these very significant advances, cultural eutrophication remains one of the foremost problems for protecting our valuable surface water resources. The papers in this special issue provide a valuable cross section and synthesis of our current understanding of both freshwater and marine eutrophication science. They also serve to identify gaps in our knowledge and will help to guide future research.
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Trematode diversity in freshwater fishes of the Globe I: 'Old World'.
Scholz, Tomáš; Besprozvannykh, Vladimir V; Boutorina, Tamara E; Choudhury, Anindo; Cribb, Thomas H; Ermolenko, Alexey V; Faltýnková, Anna; Shedko, Marina B; Shimazu, Takeshi; Smit, Nico J
2016-03-01
In this paper, we review, continent by continent, the trematode fauna of freshwater fishes of the 'Old World', a vast area consisting of the Palaearctic, Ethiopian, Oriental and Australasian zoogeographical regions. Knowledge of this fauna is highly uneven and clearly incomplete for almost all regions, sometimes dramatically so. Although the biggest problem remains the completion of the 'first pass' of alpha taxonomy, there are in addition great problems relating to biogeography and elucidation of life-cycles. For the latter, molecular data, i.e. matching DNA sequences of larval stages and corresponding adults, may represent a powerful tool that should be used in future studies. Another challenging problem represents the existence of cryptic species and, in particular, considerable decrease of experts in taxonomy and life-cycles of trematodes.
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2010-01-26
Director's Colloquium; Dr Jonathan Trent, Physical Scientist with NASA Ames Bioengineering Branch presents 'OMEGA and the Future of Aviation Fuels) Abstract: Offshore Membrane Enclosures for Growing Algae (OMEGA) is an innovative approach to growing oil-producing, freshwater algea in off shore enclosures, using municipal wastewater that is currently dumped into the ocean at a rate of >35 billion gals/day.
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2010-01-26
Director's Colloquium; Dr Jonathan Trent, Physical Scientist with NASA Ames Bioengineering Branch presents 'OMEGA and the Future of Aviation Fuels) Abstract: Offshore Membrane Enclosures for Growing Algae (OMEGA) is an innovative approach to growing oil-producing, freshwater algea in off shore enclosures, using municipal wastewater that is currently dumped into the ocean at a rate of >35 billion gals/day.
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USDA-ARS?s Scientific Manuscript database
The Ogallala Aquifer is one of the largest freshwater aquifers in the world. It acts as a valuable resource in agriculture, animal production, and public water supplies across eight Great Plains states. However, with high irrigation demand, low recharge rates across most of the region, and extreme c...
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China's natural wetlands: past problems, current status, and future challenges
Shuqing An; Harbin Li; Baohua Guan; Changfang Zhou; Zhongsheng Wang; Zifa Deng; Yingbiao Zhi; Yuhong Liu; Chi Xu; Shubo Fang; Jinhui Jiang; Hongli Li
2007-01-01
Natural wetlands, occupying 3.8% of China's land and providing 54.9% of ecosystem services, are unevenly distributed among eight wetland regions. Natural wetlands in China suffered great loss and degradation (e.g., 23.0% freshwater swamps, 51.2% coastal wetlands) because of the wetland reclamation during China's long history of civilization, and the...
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Past and future patterns of freshwater mussel extinctions in North America during the Holocene
Wendell R. Haag
2009-01-01
Humans have had profound impacts on the ecology of North America both before and since colonization by Europeans. Modern-day human impacts extend to nearly every type of habitat, but evidence for pre-Columbian human impacts is limited almost exclusively to terrestrial ecosystems. In pre-Columbian times, human activities, especially...
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Man's Impact on the Environment: The Freshwater Marsh as an Ecosystem.
ERIC Educational Resources Information Center
Brevard County School Board, Cocoa, FL.
This teaching guide deals with the ecological composition of a marsh and the ecological effects certain changes might have on a marsh. This study focuses on the fresh water marsh found in the Florida Everglades which can furnish the student with several examples of past, present, and possible future ecological changes which impact this ecosystem.…
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Facing tomorrow's challenges: U.S. Geological Survey science in the decade 2007-2017
,
2007-01-01
- A National Hazards, Risk, and Resilience Assessment Program: Ensuring the Long-Term Health and Wealth of the Nation - The Role of Environment and Wildlife in Human Health: A System that Identifies Environmental Risk to Public Health in America - A Water Census of the United States: Quantifying, Forecasting, and Securing Freshwater for America's Future
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Climate change and the future of freshwater fisheries
Daniel J. Isaak
2014-01-01
My first awareness of the importance that climate has for fish came during my summer field seasons as a Ph.D. student at the University of Wyoming. While conducting electrofishing surveys in the climatically diverse Salt River basin along the mountainous border between Wyoming and Idaho, I observed spatial patterns in species distributions and abundance that strongly...
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Characterizing a sustainability transition: Goals, targets, trends, and driving forces
Parris, Thomas M.; Kates, Robert W.
2003-01-01
Sustainable development exhibits broad political appeal but has proven difficult to define in precise terms. Recent scholarship has focused on the nature of a sustainability transition, described by the National Research Council as meeting the needs of a stabilizing future world population while reducing hunger and poverty and maintaining the planet's life-support systems. We identify a small set of goals, quantitative targets, and associated indicators that further characterize a sustainability transition by drawing on the consensus embodied in internationally negotiated agreements and plans of action. To illustrate opportunities for accelerating progress, we then examine current scholarship on the processes that influence attainment of four such goals: reducing hunger, promoting literacy, stabilizing greenhouse-gas concentrations, and maintaining fresh-water availability. We find that such analysis can often reveal “levers of change,” forces that both control the rate of positive change and are subject to policy intervention. PMID:12819346
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Inequality or injustice in water use for food?
NASA Astrophysics Data System (ADS)
Carr, J. A.; Seekell, D. A.; D'Odorico, P.
2015-02-01
The global distributions of water availability and population density are uneven and therefore inequality exists in human access to freshwater resources. Is this inequality unjust or only regrettable? To examine this question we formulated and evaluated elementary principles of water ethics relative to human rights for water, and the need for global trade to improve societal access to water by transferring ‘virtual water’ embedded in plant and animal commodities. We defined human welfare benchmarks and evaluated patterns of water use with and without trade over a 25-year period to identify the influence of trade and inequality on equitability of water use. We found that trade improves mean water use and wellbeing, relative to human welfare benchmarks, suggesting that inequality is regrettable but not necessarily unjust. However, trade has not significantly contributed to redressing inequality. Hence, directed trade decisions can improve future conditions of water and food scarcity through reduced inequality.
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Hofman, D; Monte, L; Boyer, P; Brittain, J; Donchyts, G; Gallego, E; Gheorghiu, D; Håkanson, L; Heling, R; Kerekes, A; Kocsy, G; Lepicard, S; Slavik, O; Slavnicu, D; Smith, J; Zheleznyak, M
2011-02-01
Assessment of the environmental and radiological consequences of a nuclear accident requires the management of a great deal of data and information as well as the use of predictive models. Computerised Decision Support Systems (CDSS) are essential tools for this kind of complex assessment and for assisting experts with a rational decision process. The present work focuses on the assessment of the main features of selected state-of-the-art CDSS for off-site management of freshwater ecosystems contaminated by radionuclides. This study involved both developers and end-users of the assessed CDSS and was based on practical customisation exercises, installation and application of the decision systems. Potential end-users can benefit from the availability of several ready-to-use CDSS that allow one to run different kinds of models aimed at predicting the behaviour of radionuclides in aquatic ecosystems, evaluating doses to humans, assessing the effectiveness of different kinds of environmental management interventions and ranking these interventions, accounting for their social, economic and environmental impacts. As a result of the present assessment, the importance of CDSS "integration" became apparent: in many circumstances, different CDSS can be used as complementary tools for the decision-making process. The results of this assessment can also be useful for the future development and improvement of the CDSS. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Visioning the Future: Scenarios Modeling of the Florida Coastal Everglades
NASA Astrophysics Data System (ADS)
Flower, Hilary; Rains, Mark; Fitz, Carl
2017-11-01
In this paper, we provide screening-level analysis of plausible Everglades ecosystem response by 2060 to sea level rise (0.50 m) interacting with macroclimate change (1.5 °C warming, 7% increase in evapotranspiration, and rainfall that either increases or decreases by 10%). We used these climate scenarios as input to the Ecological Landscape Model to simulate changes to seven interactive hydro-ecological metrics. Mangrove forest and other marine influences migrated up to 15 km inland in both scenarios, delineated by the saltwater front. Freshwater habitat area decreased by 25-30% under our two climate change scenarios and was largely replaced by mangroves and, in the increased rainfall scenario, open water as well. Significant mangroves drowned along northern Florida Bay in both climate change scenarios due to sea level rise. Increased rainfall of 10% provided significant benefits to the spatial and temporal salinity regime within the marine-influenced zone, providing a more gradual and natural adjustment for at-risk flora and fauna. However, increased rainfall also increased the risk of open water, due to water depths that inhibited mangrove establishment and reduced peat accumulation rates. We infer that ecological effects related to sea level rise may occur in the extreme front-edge of saltwater intrusion, that topography will control the incursion of this zone as sea level rises, and that differences in freshwater availability will have ecologically significant effects on ecosystem resilience through the temporal and spatial pattern of salinity changes.
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Visioning the Future: Scenarios Modeling of the Florida Coastal Everglades.
Flower, Hilary; Rains, Mark; Fitz, Carl
2017-11-01
In this paper, we provide screening-level analysis of plausible Everglades ecosystem response by 2060 to sea level rise (0.50 m) interacting with macroclimate change (1.5 °C warming, 7% increase in evapotranspiration, and rainfall that either increases or decreases by 10%). We used these climate scenarios as input to the Ecological Landscape Model to simulate changes to seven interactive hydro-ecological metrics. Mangrove forest and other marine influences migrated up to 15 km inland in both scenarios, delineated by the saltwater front. Freshwater habitat area decreased by 25-30% under our two climate change scenarios and was largely replaced by mangroves and, in the increased rainfall scenario, open water as well. Significant mangroves drowned along northern Florida Bay in both climate change scenarios due to sea level rise. Increased rainfall of 10% provided significant benefits to the spatial and temporal salinity regime within the marine-influenced zone, providing a more gradual and natural adjustment for at-risk flora and fauna. However, increased rainfall also increased the risk of open water, due to water depths that inhibited mangrove establishment and reduced peat accumulation rates. We infer that ecological effects related to sea level rise may occur in the extreme front-edge of saltwater intrusion, that topography will control the incursion of this zone as sea level rises, and that differences in freshwater availability will have ecologically significant effects on ecosystem resilience through the temporal and spatial pattern of salinity changes.
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A vital link: water and vegetation in the Anthropocene
NASA Astrophysics Data System (ADS)
Gerten, D.
2013-04-01
This paper argues that the interplay of water, carbon and vegetation dynamics is fundamental to some global trends in the current and conceivable future Anthropocene. Supported by simulations with a process-based biosphere model and a literature review, it demonstrates that the connectivity of freshwater and vegetation dynamics is vital for water security, food security and (terrestrial) ecosystem integrity alike. The water limitation of net primary production of both natural and agricultural plants - already pronounced in many regions - is shown to increase in many places under projected climate change, though this development is partially offset by water-saving direct CO2 effects. Natural vegetation can to some degree adapt dynamically to higher water limitation, but agricultural crops require some form of active management to overcome it - among them irrigation, soil conservation and expansion into still uncultivated areas. While crucial to secure food production for a growing world population, such human interventions in water-vegetation systems have, as also shown, repercussions to the water cycle. Indeed, land use changes have been shown to be the second-most important influence on the terrestrial water balance in recent times. Furthermore, climate change regionally increases irrigation demand and decreases freshwater availability, impeding on rainfed and irrigated food production (if not CO2 effects counterbalance this impact - which is unlikely at least in poorly managed systems). Drawing from these exemplary investigations, some research perspectives on how to further improve our quantitative knowledge of human-water-vegetation interactions in the Anthropocene are outlined.
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Role of Greenland meltwater in the changing Arctic
NASA Astrophysics Data System (ADS)
Dukhovskoy, Dmitry; Proshutinsky, Andrey; Timmermans, Mary-Louise; Myers, Paul; Platov, Gennady; Bamber, Jonathan; Curry, Beth; Somavilla, Raquel
2016-04-01
Observational data show that the Arctic ocean-ice-atmosphere system has been changing over the last two decades. Arctic change is manifest in the atypical behavior of the climate indices in the 21st century. Before the 2000s, these indices characterized the quasi-decadal variability of the Arctic climate related to different circulation regimes. Between 1948 and 1996, the Arctic atmospheric circulation alternated between anticyclonic circulation regimes and cyclonic circulation regimes with a period of 10-15 years. Since 1997, however, the Arctic has been dominated by an anticyclonic regime. Previous studies indicate that in the 20th century, freshwater and heat exchange between the Arctic Ocean and the sub-Arctic seas were self-regulated and their interactions were realized via quasi-decadal climate oscillations. What physical processes in the Arctic Ocean - sub-Arctic ocean-ice-atmosphere system are responsible for the observed changes in Arctic climate variability? The presented work is motivated by our hypothesis that in the 21st century, these quasi-decadal oscillations have been interrupted as a result of an additional freshwater source associated with Greenland Ice Sheet melt. Accelerating since the early 1990s, the Greenland Ice Sheet mass loss exerts a significant impact on thermohaline processes in the sub-Arctic seas. Surplus Greenland freshwater, the amount of which is about a third of the freshwater volume fluxed into the region during the 1970s Great Salinity Anomaly event, can spread and accumulate in the sub-Arctic seas influencing convective processes there. It is not clear, however, whether Greenland freshwater can propagate into the interior convective regions in the Labrador Sea and the Nordic Seas. In order to investigate the fate and pathways of Greenland freshwater in the sub-Arctic seas and to determine how and at what rate Greenland freshwater propagates into the convective regions, several numerical experiments using a passive tracer to track propagation of Greenland freshwater have been conducted as a part of the Forum for Arctic Ocean Modeling and Observational Synthesis effort. The presentation discusses the role of Greenland meltwater in the Arctic environment and how this can explain observed cessation of the quasi-decadal Arctic variability. The rate and pathways of Greenland meltwater in the sub-Arctic seas derived from the coordinated model experiments are analyzed. The presented study discusses a possible scenario of the Arctic in the future. It is argued that Greenland meltwater being accumulated in the sub-Arctic seas since the 1990s can trigger a negative feedback mechanism that may impede or even reverse processes of Arctic warming observed in the 21st century.
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NASA Astrophysics Data System (ADS)
Werner, Adrian D.; Sharp, Hannah K.; Galvis, Sandra C.; Post, Vincent E. A.; Sinclair, Peter
2017-08-01
On atoll islands, fresh groundwater occurs as a buoyant lens-shaped body surrounded by saltwater derived from the sea, forming the main freshwater source for many island communities. A review of the state of knowledge of atoll island groundwater is overdue given their susceptibility to adverse impacts, and the task to address water access and sanitation issues within the United Nations' Sustainable Development Goals framework before the year 2030. In this article, we review available literature to summarise the key processes, investigation techniques and management approaches of atoll island groundwater systems. Over fifty years of investigation has led to important advancements in the understanding of atoll hydrogeology, but a paucity of hydrogeological data persists on all but a small number of atoll islands. We find that the combined effects of buoyancy forces, complex geology, tides, episodic ocean events, strong climatic variability and human impacts create highly dynamic fresh groundwater lenses. Methods used to quantify freshwater availability range from simple empirical relationships to three-dimensional density-dependent models. Generic atoll island numerical models have proven popular in trying to unravel the individual factors controlling fresh groundwater lens behaviour. Major challenges face the inhabitants and custodians of atoll island aquifers, with rising anthropogenic stresses compounded by the threats of climate variability and change, sea-level rise, and some atolls already extracting freshwater at or above sustainability limits. We find that the study of atoll groundwater systems remains a critical area for further research effort to address persistent knowledge gaps, which lead to high uncertainties in water security issues for both island residents and surrounding environs.
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Head-of-tide bottleneck of particulate material transport from watersheds to estuaries
NASA Astrophysics Data System (ADS)
Ensign, Scott H.; Noe, Gregory B.; Hupp, Cliff R.; Skalak, Katherine J.
2015-12-01
We measured rates of sediment, C, N, and P accumulation at four floodplain sites spanning the nontidal through oligohaline Choptank and Pocomoke Rivers, Maryland, USA. Ceramic tiles were used to collect sediment for a year and sediment cores were collected to derive decadal sedimentation rates using 137Cs. The results showed highest rates of short- and long-term sediment, C, N, and P accumulation occurred in tidal freshwater forests at the head of tide on the Choptank and the oligohaline marsh of the Pocomoke River, and lowest rates occurred in the downstream tidal freshwater forests in both rivers. Presumably, watershed material was mostly trapped at the head of tide, and estuarine material was trapped in oligohaline marshes. This hydrologic transport bottleneck at the head of tide stores most available watershed sediment, C, N, and P creating a sediment shadow in lower tidal freshwater forests potentially limiting their resilience to sea level rise.
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Head-of-tide bottleneck of particulate material transport from watersheds to estuaries
Ensign, Scott H.; Noe, Gregory; Hupp, Cliff R.; Skalak, Katherine
2015-01-01
We measured rates of sediment, C, N, and P accumulation at four floodplain sites spanning the nontidal through oligohaline Choptank and Pocomoke Rivers, Maryland, USA. Ceramic tiles were used to collect sediment for a year and sediment cores were collected to derive decadal sedimentation rates using 137Cs. The results showed highest rates of short- and long-term sediment, C, N, and P accumulation occurred in tidal freshwater forests at the head of tide on the Choptank and the oligohaline marsh of the Pocomoke River, and lowest rates occurred in the downstream tidal freshwater forests in both rivers. Presumably, watershed material was mostly trapped at the head of tide, and estuarine material was trapped in oligohaline marshes. This hydrologic transport bottleneck at the head of tide stores most available watershed sediment, C, N, and P creating a sediment shadow in lower tidal freshwater forests potentially limiting their resilience to sea level rise.
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Phelps, G.G.; Rohrer, K.P.
1987-01-01
Northeast Seminole County, Florida, contains an isolated recharge area of the Floridan aquifer system that forms a freshwater lens completely surrounded by saline water. The freshwater lens covers an area of about 22 sq mi surrounding the town of Geneva, and generally is enclosed by the 25 ft land surface altitude contour. Thickness of the lens is about 350 ft in the center of the recharge area. The geohydrologic units in descending order consist of the post-Miocene sand and shell of the surficial aquifer; Miocene clay, sand, clay, and shell that form a leaky confining bed; and permeable Eocene limestones of the Floridan aquifer system. The freshwater lens is the result of local rainfall flushing ancient seawater from the Floridan aquifer system. Sufficient quantities of water for domestic and small public supply systems are available from the Floridan aquifer system in the Geneva area. The limiting factor for water supply in the area is the chemical quality of the water. Chloride concentrations range from < 20 mg/L in the center of the recharge area to about 5,100 mg/L near the St. Johns River southeast of Geneva. Constituents analyzed included sulfate (range 1 to 800 mg/L), hardness (range 89 to 2,076 mg/L), and iron (range 34 to 6,600 mg/L). Because the freshwater lens results entirely from local recharge, the long-term sustained freshwater yield of the aquifer in the Geneva area depends on the local recharge rate. In 1982, recharge was about 13 inches (13.8 million gal/day). Average recharge for 1941 through 1970 was estimated to be about 11 inches (11.3 million gal/day). Freshwater that recharges the aquifer in the Geneva area is either pumped out or flows north and northeast to discharge near or in the St. Johns River. Average annual outflow from the lens is about 10 in/yr. No measurable change in the size or location of the freshwater lens has occurred since studies in the early 1950's. (Lantz-PTT)
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NASA Astrophysics Data System (ADS)
Buzzelli, Christopher; Doering, Peter H.; Wan, Yongshan; Sun, Detong; Fugate, David
2014-12-01
Variations in freshwater inflow have ecological consequences for estuaries ranging among eutrophication, flushing and transport, and high and low salinity impacts on biota. Predicting the potential effects of the magnitude and composition of inflow on estuaries over a range of spatial and temporal scales requires reliable mathematical models. The goal of this study was to develop and test a model of ecosystem processes with variable freshwater inflow to the sub-tropical Caloosahatchee River Estuary (CRE) in southwest Florida from 2002 to 2009. The modeling framework combined empirically derived inputs of freshwater and materials from the watershed, daily predictions of salinity, a box model for physical transport, and simulation models of biogeochemical and seagrass dynamics. The CRE was split into 3 segments to estimate advective and dispersive transport of water column constituents. Each segment contained a sub-model to simulate changes in the concentrations of organic nitrogen and phosphorus (ON and OP), ammonium (NH4+), nitrate-nitrite (NOx-), ortho-phosphate (PO4-3), phytoplankton chlorophyll a (CHL), and sediment microalgae (SM). The seaward segment also had sub-models for seagrasses (Halodule wrightii and Thalassia testudinum). The model provided realistic predictions of ON in the upper estuary during wet conditions since organic nitrogen is associated with freshwater inflow and low salinity. Although simulated CHL concentrations were variable, the model proved to be a reliable predictor in time and space. While predicted NOx- concentrations were proportional to freshwater inflow, NH4+ was less predictable due to the complexity of internal cycling during times of reduced freshwater inflow. Overall, the model provided a representation of seagrass biomass changes despite the absence of epiphytes, nutrient effects, or sophisticated translocation in the formulation. The model is being used to investigate the relative importance of colored dissolved organic matter (CDOM) vs. CHL in submarine light availability throughout the CRE, assess if reductions in nutrient loads are more feasible by controlling freshwater quantity or N and P concentrations, and explore the role of inflow and flushing on the fates of externally and internally derived dissolved and particulate constituents.
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Sensitivity of Circulation in the Skagit River Estuary to Sea Level Rise and Future Flows
DOE Office of Scientific and Technical Information (OSTI.GOV)
Khangaonkar, Tarang; Long, Wen; Sackmann, Brandon
Future climate simulations based on the Intergovernmental Panel on Climate Change emissions scenario (A1B) have shown that the Skagit River flow will be affected, which may lead to modification of the estuarine hydrodynamics. There is considerable uncertainty, however, about the extent and magnitude of resulting change, given accompanying sea level rise and site-specific complexities with multiple interconnected basins. To help quantify the future hydrodynamic response, we developed a three dimensional model of the Skagit River estuary using the Finite Volume Coastal Ocean Model (FVCOM). The model was set up with localized high-resolution grids in Skagit and Padilla Bay sub-basins withinmore » the intermediate-scale FVCOM based model of the Salish Sea (greater Puget Sound and Georgia Basin). Future changes to salinity and annual transport through the basin were examined. The results confirmed the existence of a residual estuarine flow that enters Skagit Bay from Saratoga Passage to the south and exits through Deception Pass. Freshwater from the Skagit River is transported out in the surface layers primarily through Deception Pass and Saratoga Passage, and only a small fraction (≈4%) is transported to Padilla Bay. The moderate future perturbations of A1B emissions, corresponding river flow, and sea level rise of 0.48 m examined here result only in small incremental changes to salinity structure and inter-basin freshwater distribution and transport. An increase in salinity of ~1 ppt in the near-shore environment and a salinity intrusion of approximately 3 km further upstream is predicted in Skagit River, well downstream of the drinking water intakes.« less
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NASA Astrophysics Data System (ADS)
Swarzenski, P. W.
2015-12-01
More than 90% of the world's ~400 larger atoll islands are located in the Pacific and Indian Oceans and are inhabited by ~ 3/4 million people. As ground elevations of these atolls rarely exceed a few meters above mean sea level, atoll communities must rely precariously on finite resources, including fresh water and land. When demand for water exceeds precipitation rates, fresh groundwater may provide an additional, albeit also limited resource. The shape and size of this freshwater lens is controlled by precipitation, infiltration, discharge, and groundwater pumping, as well as hydrogeologic characteristics of the aquifer, and climate. Small atoll islands like Roi Namur on Kwajalein perhaps best illustrate the strong interdependence of the islet's depositional history and geochemical transformations that occur within the shallow aquifer and its host rock. This study utilized electrical resistivity tomography (ERT) to define the position of the freshwater lens above underlying seawater and to examine scales of freshwater /saltwater mixing. Time series Rn-222 measurements were used to evaluate groundwater discharge rates to the coastal waters, and a suite of groundwater geochemical tracers, including select nutrients, trace elements, and water isotopes, were used to develop a better understanding of how the fresh water lens will likely to respond to external perturbations, such as managed recharge, and the inevitability of future marine over wash events that will be become more frequent and severe under expected sea level rise.
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Patterns of Freshwater Species Richness, Endemism, and Vulnerability in California
Furnish, Joseph; Gardali, Thomas; Grantham, Ted; Katz, Jacob V. E.; Kupferberg, Sarah; McIntyre, Patrick; Moyle, Peter B.; Ode, Peter R.; Peek, Ryan; Quiñones, Rebecca M.; Rehn, Andrew C.; Santos, Nick; Schoenig, Steve; Serpa, Larry; Shedd, Jackson D.; Slusark, Joe; Viers, Joshua H.; Wright, Amber; Morrison, Scott A.
2015-01-01
The ranges and abundances of species that depend on freshwater habitats are declining worldwide. Efforts to counteract those trends are often hampered by a lack of information about species distribution and conservation status and are often strongly biased toward a few well-studied groups. We identified the 3,906 vascular plants, macroinvertebrates, and vertebrates native to California, USA, that depend on fresh water for at least one stage of their life history. We evaluated the conservation status for these taxa using existing government and non-governmental organization assessments (e.g., endangered species act, NatureServe), created a spatial database of locality observations or distribution information from ~400 data sources, and mapped patterns of richness, endemism, and vulnerability. Although nearly half of all taxa with conservation status (n = 1,939) are vulnerable to extinction, only 114 (6%) of those vulnerable taxa have a legal mandate for protection in the form of formal inclusion on a state or federal endangered species list. Endemic taxa are at greater risk than non-endemics, with 90% of the 927 endemic taxa vulnerable to extinction. Records with spatial data were available for a total of 2,276 species (61%). The patterns of species richness differ depending on the taxonomic group analyzed, but are similar across taxonomic level. No particular taxonomic group represents an umbrella for all species, but hotspots of high richness for listed species cover 40% of the hotspots for all other species and 58% of the hotspots for vulnerable freshwater species. By mapping freshwater species hotspots we show locations that represent the top priority for conservation action in the state. This study identifies opportunities to fill gaps in the evaluation of conservation status for freshwater taxa in California, to address the lack of occurrence information for nearly 40% of freshwater taxa and nearly 40% of watersheds in the state, and to implement adequate protections for freshwater taxa where they are currently lacking. PMID:26147215
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NASA Astrophysics Data System (ADS)
Gunnars, Anneli; Blomqvist, Sven; Johansson, Peter; Andersson, Christian
2002-03-01
The formation of Fe(III) oxyhydroxide colloids by oxidation of Fe(II) and their subsequent aggregation to larger particles were studied in laboratory experiments with natural water from a freshwater lake and a brackish coastal sea. Phosphate was incorporated in the solid phase during the course of hydrolysis of iron. The resulting precipitated amorphous Fe(III) oxyhydroxide phases were of varying composition, depending primarily on the initial dissolved Fe/P molar ratio, but with little influence by salinity or concentration of calcium ions. The lower limiting Fe/P ratio found for the solid phase suggests the formation of a basic Fe(III) phosphate compound with a stoichiometric Fe/P ratio of close to two. This implies that an Fe/P stoichiometry of ≈2 ultimately limits the capacity of precipitating Fe(III) to fix dissolved phosphate at oxic/anoxic boundaries in natural waters. In contrast to phosphorus, the uptake of calcium seemed to be controlled by sorption processes at the surface of the iron-rich particles formed. This uptake was more efficient in freshwater than in brackish water, suggesting that salinity restrains the uptake of calcium by newly formed Fe(III) oxyhydroxides in natural waters. Moreover, salinity enhanced the aggregation rate of the colloids formed. The suspensions were stabilised by the presence of organic matter, although this effect was less pronounced in seawater than in freshwater. Thus, in seawater of 6 to 33 ‰S, the removal of particles was fast (removal half time < 200 h), whereas the colloidal suspensions formed in freshwater were stable (removal half time > 900 h). Overall, oxidation of Fe(II) and removal of Fe(III) oxyhydroxide particles were much faster in seawater than in freshwater. This more rapid turnover results in lower iron availability in coastal seawater than in freshwater, making iron more likely to become a limiting element for chemical scavenging and biologic production.
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NASA Astrophysics Data System (ADS)
Stalker, J. C.; Price, R. M.; Swart, P. K.
2005-05-01
Biscayne Bay is a sub-tropical estuary located on the carbonate platform of south Florida. The water occupying Biscayne Bay is a balance of saltwater influx from the open ocean and freshwater inputs from precipitation, surface water runoff, and submarine groundwater discharge. The bays watershed includes a total of 3 million inhabitants, the major urban centers of Miami and Ft. Lauderdale, as well as the Everglades system. With the development of south Florida, the natural diffuse groundwater and stream flow into the bay has been replaced by a large system of canals and levees in an effort to control flooding and drain swampland. The Comprehensive Everglades Restoration Plan includes changes in the freshwater deliveries to Biscayne Bay from point-source discharges via canals to non-point source discharges via wetlands and groundwater flow. The balance of salinity in Biscayne Bay effects sensitive seagrass and tidal ecosystems including numerous species of corals and other biota. A comprehensive understanding of the flow of freshwater into the bay is crucial to future planned developments and restorations. The goal of this study is to use naturally occurring geochemical constituents as tracers to identify and quantify the sources of freshwater, i.e. rainfall, canal flow, and groundwater, discharge to Biscayne Bay. In this study, discrete samples of precipitation, canal water, terrestrial groundwater, marine groundwater, and bay surface water are collected monthly and analyzed for the stable isotopes of hydrogen and oxygen as well as for major cations and anions. Initial results indicate that fresh groundwater has an isotopic signature (del 18O = -2.66 per mil, del D, -7.60 per mil) similar to rainfall (del 18O = -2.86 per mil, del D =-4.78 per mil). In contrast canal water has a heavy isotopic signature (del 18O = -0.46 per mil, del D = -2.48 per mil) due to evaporation. Thus it is possible to use stable isotopes of oxygen and hydrogen to separate canal water from precipitation and groundwater as a source of freshwater into the bay. Other geochemical constituents, such as calcium and magnesium are being investigated to further discern between the sources of canal water, rainfall and fresh groundwater. Both the stable isotopes and ion values will be placed in a mixing model to quantify and discern the dominant sources of freshwater into the Bay in both time and space.
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NASA Astrophysics Data System (ADS)
Hejazi, M. I.; Edmonds, J. A.; Clarke, L. E.; Kyle, P.; Davies, E. G.; Chaturvedi, V.; Patel, P.; Eom, J.; Wise, M.; Kim, S.; Calvin, K. V.; Moss, R. H.
2012-12-01
We investigate the relative effects of climate emission mitigation policies and socioeconomic drivers on water scarcity conditions over the 21st century both globally and regionally, by estimating both water availability and demand within a technologically-detailed global integrated assessment model of energy, agriculture, and climate change - the Global Change Assessment Model (GCAM). We first develop a global gridded monthly hydrologic model that reproduces historical streamflow observations and simulates the future availability of freshwater under both a changing climate and an evolving landscape, and incorporate this model into GCAM. We then develop and incorporate technologically oriented representations of water demands for the agricultural (irrigation and livestock), energy (electricity generation, primary energy production and processing), industrial (manufacturing and mining), and municipal sectors. The energy, industrial, and municipal sectors are represented in fourteen geopolitical regions, with the agricultural sector further disaggregated into as many as eighteen agro-ecological zones (AEZs) within each region. To perform the water scarcity analysis at the grid scale, the global water demands for the six demand sectors are spatially downscaled to 0.5 o x 0.5o resolution to match the scale of GWAM. The water scarcity index (WSI) compares total water demand to the total amount of renewable water available, and defines extreme water scarcity in any region as demand greater than 40% of total water availability. Using a reference scenario (i.e., no climate change mitigation policy) with radiative forcing reaching 8.8 W/m2 by 2095 and a global population of 14 billion, global annual water demand grows from about 9% of total annual renewable freshwater in 2005 to about 32% by 2095. This results in almost half of the world population living under extreme water scarcity by the end of the 21st century. Regionally, the demands for water exceed the total renewable freshwater available in two GCAM regions, the Middle East and India. Additionally, 20% and 27% of the global population in years 2050 and 2095, respectively, is projected to live in areas (grid cells) that will experience greater water demands than the amount of renewable water available in a year (i.e., WSI > 1.0). We also investigate the effects of emission mitigation policies on water demand and compare them to the contribution of socioeconomic drivers both globally and regionally. Three climate policy scenarios with increasing mitigation stringency of 7.7, 5.5, and 4.2 W/m2 in year 2095, under two carbon tax regimes (a universal carbon tax (UCT) which includes land use change emissions, and a fossil fuel and industrial emissions carbon tax (FFICT) which excludes land use change emissions) are analyzed. With more stringent climate mitigation targets, water scarcity declines under a UCT mitigation policy while increases with a FFICT mitigation scenario by the year 2095. The decreasing trend with UCT policy stringency is due to substitution from more water-intensive to less water-intensive choices in food, energy, and land use. Under the FFICT scenario, water scarcity is projected to increase driven by higher water demands for bio-energy crops.
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NASA Astrophysics Data System (ADS)
Wijnhoven, S.; Sistermans, W.; Hummel, H.
2008-01-01
Water works during the 1960s and 1970s changed the northern part of the Rhine-Meuse estuary in the south-west of the Netherlands into a freshwater lake, from west to east divided into three basins called the Haringvliet, the Hollands Diep and the Biesbosch. Concurrently water quality parameters (e.g. nutrients and pollutants) changed drastically during the last 50 years. This study combines macrozoobenthic monitoring data from the region from 1960 to 2001 with trends in abiotic parameters to evaluate historic developments of the communities, including densities, species numbers and diversity, and assess future developments as a first step to a rehabilitation of the estuary as planned for January 01, 2008. During the 1960s, the macrozoobenthic densities of Oligochaeta and/or Polychaeta dominated communities increased with a gradual decrease of saltwater intrusion and salinity variability. The first years after the basins became stagnant, the species numbers per sample and the Shannon diversity were high due to the coexistence of salt and freshwater species. An increase in nutrient and pollutant loads led to a decrease in the macrozoobenthos densities. As water and sediment quality gradually improved, nowadays the former estuary contains high diversity and high density macrozoobenthic communities, whereas Oligochaeta and/or Polychaeta were dominant in the 1960s, and Bivalvia and Gastropoda were more abundant during the 1970s. Macrozoobenthic communities moved from the east to west with a time-lag, which may primarily be attributed to changing salinities, salinity variances and oxygen levels. Therefore, the current communities of the Haringvliet show similarities with the communities that occurred already during the 1960s in the Biesbosch. This study shows the value of macrozoobenthos monitoring data over longer periods. The possible impact of a new saltwater inlet in the west of the Haringvliet, allowing in the near future saltwater to enter 11.5 km eastward, yet alternated by frequent flushing with freshwater to ascertain that the salt intrusion does not reach further, on the development of the macrozoobentic communities is discussed.
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Selected hydrogeologic and water-quality data from Jones Beach Island, Long Island, New York
Scorca, M.P.; Reilly, T.E.; Franke, O.L.
1995-01-01
A data-collection site was instrumented on Jones Beach Island, a barrier island south of Long Island, N.Y., to study local freshwater/ saltwater relations in the shallow ground-water system. A geologic test boring revealed about 88 feet of well-sorted glacial outwash sand above about 15 feet of Gardiners Clay, which directly overlies silty sand of the Magothy Formation. Tidal effects on water levels in Great South Bay, the upper glacial aquifer, and the Magothy aquifer were observed and quantified with a tidal gage in the bay and analog water-level recorders in the wells.Chloride concentrations in the upper Magothy aquifer were higher than expected--about 270 mg/L (milligrams per liter), and those in the upper glacial aquifer were 17,000 to 19,000 mg/L, about the same as in Great South Bay. Estimates of pressure and freshwater equivalent heads indicate that, at the data-collection site, freshwater is discharging upward from the Magothy aquifer into the salty upper glacial aquifer, but dilution by this freshwater is undetectable. The reason for the elevated chloride concentration in the Magothy aquifer cannot be determined from available hydrogeologic information.
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Emissions of sulfur gases from wetlands
NASA Technical Reports Server (NTRS)
Hines, Mark E.
1992-01-01
Data on the emissions of sulfur gases from marine and freshwater wetlands are summarized with respect to wetland vegetation type and possible formation mechanisms. The current data base is largest for salt marshes inhabited by Spartina alterniflora. Both dimethyl sulfide (DMS) and hydrogen sulfide (H2S) dominate emissions from salt marshes, with lesser quantities of methyl mercaptan (MeSH), carbonyl sulfide (COS), carbon disulfide (CS2) and dimethyl disulfide (DMDS) being emitted. High emission rates of DMS are associated with vegetation that produces the DMS precursor dimethylsulfonionpropionate (DMSP). Although large quantities of H2S are produced in marshes, only a small percentage escapes to the atmosphere. High latitude marshes emit less sulfur gases than temperate ones, but DMS still dominates. Mangrove-inhabited wetlands also emit less sulfur than temperate S. alterniflora marshes. Few data are available on sulfur gas emissions from freshwater wetlands. In most instances, sulfur emissions from temperate freshwater sites are low. However, some temperate and subtropical freshwater sites are similar in magnitude to those from marine wetlands which do not contain vegetation that produces DMSP. Emissions are low in Alaskan tundra but may be considerably higher in some bogs and fens.
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Economic analysis of municipal wastewater utilization for thermoelectric power production
DOE Office of Scientific and Technical Information (OSTI.GOV)
Safari, I.; Walker, M.; Abbasian, J.
2011-01-01
The thermoelectric power industry in the U.S. uses a large amount of freshwater. The large water demand is increasingly a problem, especially for new power plant development, as availability of freshwater for new uses diminishes in the United States. Reusing non-traditional water sources, such as treated municipal wastewater, provides one option to mitigate freshwater usage in the thermoelectric power industry. The amount of freshwater withdrawal that can be displaced with non-traditional water sources at a particular location requires evaluation of the water management and treatment requirements, considering the quality and abundance of the non-traditional water sources. This paper presents themore » development of an integrated costing model to assess the impact of degraded water treatment, as well as the implications of increased tube scaling in the main condenser. The model developed herein is used to perform case studies of various treatment, condenser cleaning and condenser configurations to provide insight into the ramifications of degraded water use in the cooling loops of thermoelectric power plants. Further, this paper lays the groundwork for the integration of relationships between degraded water quality, scaling characteristics and volatile emission within a recirculating cooling loop model.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Starr, R.C.; Green, T.S.; Hull, L.C.
2001-02-28
A review has been performed of existing information that describes geology, hydrogeology, and geochemistry at the South District Wastewater Treatment Plant, which is operated by the Miami-Dade Water and Sewer Department, in Dade County, Florida. Treated sanitary wastewater is injected into a saline aquifer beneath the plant. Detection of contaminants commonly associated with treated sanitary wastewater in the freshwater aquifer that overlies the saline aquifer has indicated a need for a reevaluation of the ability of the confining layer above the saline aquifer to prevent fluid migration into the overlying freshwater aquifer. Review of the available data shows that themore » geologic data set is not sufficient to demonstrate that a competent confining layer is present between the saline and freshwater aquifers. The hydrogeologic data also do not indicate that a competent confining layer is present. The geochemical data show that the freshwater aquifer is contaminated with treated wastewater, and the spatial patterns of contamination are consistent with upward migration through localized conduits through the Middle Confining Unit, such as leaking wells or natural features. Recommendations for collection and interpretation of additional site characterization data are provided.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Starr, Robert Charles; Green, Timothy Scott; Hull, Laurence Charles
2001-02-01
A review has been performed of existing information that describes geology, hydrogeology, and geochemistry at the South District Wastewater Treatment Plant, which is operated by the Miami-Dade Water and Sewer Department, in Dade County, Florida. Treated sanitary wastewater is injected into a saline aquifer beneath the plant. Detection of contaminants commonly associated with treated sanitary wastewater in the freshwater aquifer that overlies the saline aquifer has indicated a need for a reevaluation of the ability of the confining layer above the saline aquifer to prevent fluid migration into the overlying freshwater aquifer. Review of the available data shows that themore » geologic data set is not sufficient to demonstrate that a competent confining layer is present between the saline and freshwater aquifers. The hydrogeologic data also do not indicate that a competent confining layer is present. The geochemical data show that the freshwater aquifer is contaminated with treated wastewater, and the spatial patterns of contamination are consistent with upward migration through localized conduits through the Middle Confining Unit, such as leaking wells or natural features. Recommendations for collection and interpretation of additional site characterization data are provided.« less
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Prioritizing research for trace pollutants and emerging contaminants in the freshwater environment.
Murray, Kyle E; Thomas, Sheeba M; Bodour, Adria A
2010-12-01
Organic chemicals have been detected at trace concentrations in the freshwater environment for decades. Though the term trace pollutant indicates low concentrations normally in the nanogram or microgram per liter range, many of these pollutants can exceed an acceptable daily intake (ADI) for humans. Trace pollutants referred to as emerging contaminants (ECs) have recently been detected in the freshwater environment and may have adverse human health effects. Analytical techniques continue to improve; therefore, the number and frequency of detections of ECs are increasing. It is difficult for regulators to restrict use of pollutants that are a human health hazard; scientists to improve treatment techniques for higher priority pollutants; and the public to modify consumption patterns due to the vast number of ECs and the breadth of literature on the occurrence, use, and toxicity. Hence, this paper examines literature containing occurrence and toxicity data for three broad classes of trace pollutants and ECs (industrials, pesticides, and pharmaceuticals and personal care products (PPCPs)), and assesses the relevance of 71 individual compounds. The evaluation indicates that widely used industrials (BPF) and PPCPs (AHTN, HHCB, ibuprofen, and estriol) occur frequently in samples from the freshwater environment but toxicity data were not available; thus, it is important to establish their ADI. Other widely used industrials (BDE-47, BDE-99) and pesticides (benomyl, carbendazim, aldrin, endrin, ethion, malathion, biphenthrin, and cypermethrin) have established ADI values but occurrence in the freshwater environment was not well documented. The highest priority pollutants for regulation and treatment should include industrials (PFOA, PFOS and DEHP), pesticides (diazinon, methoxychlor, and dieldrin), and PPCPs (EE2, carbamazepine, βE2, DEET, triclosan, acetaminophen, and E1) because they occur frequently in the freshwater environment and pose a human health hazard at environmental concentrations. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Saylor, Ryan K.; Miller, Debra L.; Vandersea, Mark W.; Bevelhimer, Mark S.; Schofield, Pamela J.; Bennett, Wayne A.
2010-01-01
Epizootic ulcerative syndrome (EUS) caused by the oomycete Aphanomyces invadans is an invasive, opportunistic disease of both freshwater and estuarine fishes. Originally documented as the cause of mycotic granulomatosis of ornamental fishes in Japan and as the cause of EUS of fishes in southeast Asia and Australia, this pathogen is also present in estuaries and freshwater bodies of the Atlantic and gulf coasts of the USA. We describe a mass mortality event of 343 captive juvenile bullseye snakehead Channa marulius collected from freshwater canals in Miami-Dade County, Florida. Clinical signs appeared within the first 2 d of captivity and included petechiae, ulceration, erratic swimming, and inappetence. Histological examination revealed hyphae invading from the skin lesions deep into the musculature and internal organs. Species identification was confirmed using a species-specific PCR assay. Despite therapeutic attempts, 100% mortality occurred. This represents the first documented case of EUS in bullseye snakehead fish collected from waters in the USA. Future investigation of the distribution and prevalence of A. invadans within the bullseye snakehead range in south Florida may give insight into this pathogen-host system.
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Local adaptation of Gymnocypris przewalskii (Cyprinidae) on the Tibetan Plateau
Zhang, Renyi; Ludwig, Arne; Zhang, Cunfang; Tong, Chao; Li, Guogang; Tang, Yongtao; Peng, Zuogang; Zhao, Kai
2015-01-01
Divergent selection among environments affects species distributions and can lead to speciation. In this article, we investigated the transcriptomes of two ecotypes of scaleless carp (Gymnocypris przewalskii przewalskii and G. p. ganzihonensis) from the Tibetan Plateau. We used a transcriptome sequencing approach to screen approximately 250,000 expressed sequence tags (ESTs) from the gill and kidney tissues of twelve individuals from the Ganzi River and Lake Qinghai to understand how this freshwater fish has adapted to an ecological niche shift from saline to freshwater. We identified 9,429 loci in the gill transcriptome and 12,034 loci in the kidney transcriptome with significant differences in their expression, of which 242 protein-coding genes exhibited strong positive selection (Ka/Ks > 1). Many of the genes are involved in ion channel functions (e.g., Ca2+-binding proteins), immune responses (e.g., nephrosin) or cellular water absorption functions (e.g., aquaporins). These results have potentially broad importance in understanding shifts from saline to freshwater habitats. Furthermore, this study provides the first transcriptome of G. przewalskii, which will facilitate future ecological genomics studies and aid in the identification of genes underlying adaptation and incipient ecological speciation. PMID:25944748
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Trematode diversity in freshwater fishes of the Globe II: 'New World'.
Choudhury, Anindo; Aguirre-Macedo, M Leopoldina; Curran, Stephen S; de Núñez, Margarita Ostrowski; Overstreet, Robin M; de León, Gerardo Pérez-Ponce; Santos, Cláudia Portes
2016-03-01
We provide a summary overview of the diversity of trematode parasites in freshwater fishes of the 'New World', i.e. the Americas, with emphasis on adult forms. The trematode fauna of three regions, South America, Middle America, and USA and Canada (North America north of Mexico), are considered separately. In total, 462 trematode species have been reported as adults from the Americas. The proportion of host species examined for parasites varies widely across the Americas, from a high of 45% in the Mexican region of Middle America to less than 5% in South America. North and South America share no adult species, and one exclusively freshwater genus, Creptotrema Travassos, Artigas & Pereira, 1928 in the Allocreadiidae Looss, 1902 is the most widely distributed. Metacercariae of strigeiforms maturing in fish-eating birds (e.g. species of the Diplostomidae Poirier, 1886) are common and widely distributed. The review also highlights the paucity of known life-cycles. The foreseeable future of diversity studies belongs to integrative approaches and the application of molecular ecological methods. While opportunistic sampling will remain important in describing and cataloguing the trematode fauna, a better understanding of trematode diversity and biology will also depend on strategic sampling throughout the Americas.
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Freshwater Sediment Characterization Factors of Copper Oxide Nanoparticles
NASA Astrophysics Data System (ADS)
Pu, Yubing; Laratte, Bertrand; Ionescu, Rodica Elena
2017-01-01
Wide use of engineered nanoparticles (ENPs) is likely to result in the eventually accumulation of ENPs in sediment. The benthic organisms living in sediments may suffer relatively high toxic effects of ENPs. This study has selected copper oxide nanoparticles (nano-CuO) as a research object. To consider the impacts of spatial heterogeneity on ENPs toxicity, the characterization factor (CF) derived from life cycle assessment (LCA) methodology is used as an indicator in this study. A nano-specific fate model has been used to calculate the freshwater sediment fate factor (FF) of nano-CuO. A literature survey of the nano-CuO toxicology values has been performed to calculate the effect factor (EF). Seventeen freshwater sediment CFs of nano-CuO are proposed as recommended values for subcontinental regions. The region most likely to be affected by nano-CuO is northern Australia (CF of 21.01·103 CTUe, comparative toxic units) and the least likely is northern Europe and northern Canada (CF of 8.55·103 CTUe). These sediment CFs for nano-CuO could be used in the future when evaluating the ecosystem impacts of products containing nano-CuO by LCA method.
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Stoks, Robby; Geerts, Aurora N; De Meester, Luc
2014-01-01
We integrated the evidence for evolutionary and plastic trait changes in situ in response to climate change in freshwater invertebrates (aquatic insects and zooplankton). The synthesis on the trait changes in response to the expected reductions in hydroperiod and increases in salinity indicated little evidence for adaptive, plastic, and genetic trait changes and for local adaptation. With respect to responses to temperature, there are many studies on temporal trait changes in phenology and body size in the wild that are believed to be driven by temperature increases, but there is a general lack of rigorous demonstration whether these trait changes are genetically based, adaptive, and causally driven by climate change. Current proof for genetic trait changes under climate change in freshwater invertebrates stems from a limited set of common garden experiments replicated in time. Experimental thermal evolution experiments and common garden warming experiments associated with space-for-time substitutions along latitudinal gradients indicate that besides genetic changes, also phenotypic plasticity and evolution of plasticity are likely to contribute to the observed phenotypic changes under climate change in aquatic invertebrates. Apart from plastic and genetic thermal adjustments, also genetic photoperiod adjustments are widespread and may even dominate the observed phenological shifts.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Saylor, Ryan; Miller, Debra; Vandersea, Mark
2010-02-01
Epizootic ulcerative syndrome (EUS) caused by the oomycete Aphanomyces invadans is an invasive, opportunistic disease of both freshwater and estuarine fishes. Originally documented as the cause of mycotic granulomatosis of ornamental fishes in Japan and as the cause of EUS of fishes in southeast Asia and Australia, this pathogen is also present in estuaries and freshwater bodies of the Atlantic and gulf coasts of the USA. We describe a mass mortality event of 343 captive juvenile bullseye snakehead Channa marulius collected from freshwater canals in Miami-Dade County, Florida. Clinical signs appeared within the first 2 d of captivity and includedmore » petechiae, ulceration, erratic swimming, and inappetence. Histological examination revealed hyphae invading from the skin lesions deep into the musculature and internal organs. Species identification was confirmed using a species-specific PCR assay. Despite therapeutic attempts, 100% mortality occurred. This represents the first documented case of EUS in bullseye snakehead fish collected from waters in the USA. Future investigation of the distribution and prevalence of A. invadans within the bullseye snakehead range in south Florida may give insight into this pathogen-host system.« less
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Past and future freshwater use in the United States
Thomas C. Brown
1999-01-01
Water use in the United States to the year 2040 is estimated by extending past trends in basic water-use determinants. Those trends are largely encouraging. Over the past 35 years, withdrawals in industry and at thermoelectric plants have steadily dropped per unit of output, and over the past 15 years some irrigated regions have also increased the efficiency of their...
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NASA Astrophysics Data System (ADS)
Muhling, B.; Gaitan, C. F.; Tommasi, D.; Saba, V. S.; Stock, C. A.; Dixon, K. W.
2016-02-01
Estuaries of the northeastern United States provide essential habitat for many anadromous fishes, across a range of life stages. Climate change is likely to impact estuarine environments and habitats through multiple pathways. Increasing air temperatures will result in a warming water column, and potentially increased stratification. In addition, changes to precipitation patterns may alter freshwater inflow dynamics, leading to altered seasonal salinity regimes. However, the spatial resolution of global climate models is generally insufficient to resolve these processes at the scale of individual estuaries. Global models can be downscaled to a regional resolution using a variety of dynamical and statistical methods. In this study, we examined projections of estuarine conditions, and future habitat extent, for several anadromous fishes in the Chesapeake Bay using different statistical downscaling methods. Sources of error from physical and biological models were quantified, and key areas of uncertainty were highlighted. Results suggested that future projections of the distribution and recruitment of species most strongly linked to freshwater flow dynamics had the highest levels of uncertainty. The sensitivity of different life stages to environmental conditions, and the population-level responses of anadromous species to climate change, were identified as important areas for further research.
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Simulating the impact of brine from desalination plants on the salinity of the Persian/Arabian Gulf
NASA Astrophysics Data System (ADS)
Eltahir, E. A. B.; Ibrahim, H. D.
2016-12-01
The Middle East has an arid climate and very little freshwater from river runoff, which has forced a rapid expansion of desalination plants in the region in order to meet current and future freshwater demand due to rising population. The Gulf is the source of feedwater and sink of concentrated discharge (brine) for plants producing more than half of the world's desalination capacity. Moreover, the Gulf is one of the most saline water bodies in the world due to large evaporation that far exceeds the input of freshwater from precipitation and river runoff. An increase in salinity at the regional scale due to brine discharge may reduce the quality of feedwater to plants and efficiency of desalination, and at the basin scale, a rise in salinity may change the dynamics of water circulation and adversely impact the marine biota. Here we present modeling results from simulating the impact of desalination on the natural Gulf environment using a coupled Gulf-atmosphere regional model (GARM). GARM is the first two-way coupled model developed for the Gulf system. The hydrodynamic component of GARM is the unstructured grid finite volume coastal ocean model (FVCOM) and the atmosphere component of GARM is the MIT regional climate model (MRCM), both of which have been widely used in simulating regional ocean and atmospheric dynamics. Desalination activity is incorporated into GARM as a boundary condition and the Gulf system is simulated for a ten-year time period in order to quantify the impact of brine discharge both at regional and basin scales. These results will be useful for desalination plant design and planning for current and future water security in the region.
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Strecker, A.L.; Olden, J.D.; Whittier, Joanna B.; Paukert, C.P.
2011-01-01
To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent attention, research has rarely considered the potential tradeoffs between protecting different dimensions of biodiversity and the ecological processes that maintain diversity. We provide the first systematic prioritization for freshwaters (focusing on the highly threatened and globally distinct fish fauna of the Lower Colorado River Basin, USA) simultaneously considering scenarios of: taxonomic, functional, and phylogenetic diversity;contemporary threats to biodiversity (including interactions with nonnative species);and future climate change and human population growth. There was 75% congruence between areas of highest conservation priority for different aspects of biodiversity, suggesting that conservation efforts can concurrently achieve strong complementarity among all types of diversity. However, sizable fractions of the landscape were incongruent across conservation priorities for different diversity scenarios, underscoring the importance of considering multiple dimensions of biodiversity and highlighting catchments that contribute disproportionately to taxonomic, functional, and phylogenetic diversity in the region. Regions of projected human population growth were not concordant with conservation priorities;however, higher human population abundance will likely have indirect effects on native biodiversity by increasing demand for water. This will come in direct conflict with projected reductions in precipitation and warmer temperatures, which have substantial overlap with regions of high contemporary diversity. Native and endemic fishes in arid ecosystems are critically endangered by both current and future threats, but our results highlight the use of systematic conservation planning for the optimal allocation of limited resources that incorporates multiple and complementary conservation values describing taxonomic, functional, and phylogenetic diversity. ??2011 by the Ecological Society of America.
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Strecker, Angela L.; Olden, Julian D.; Whittier, Joanna B.; Paukert, Craig P.
2011-01-01
To date, the predominant use of systematic conservation planning has been to evaluate and conserve areas of high terrestrial biodiversity. Although studies in freshwater ecosystems have received recent attention, research has rarely considered the potential trade-offs between protecting different dimensions of biodiversity and the ecological processes that maintain diversity. We provide the first systematic prioritization for freshwaters (focusing on the highly threatened and globally distinct fish fauna of the Lower Colorado River Basin, USA) simultaneously considering scenarios of: taxonomic, functional, and phylogenetic diversity; contemporary threats to biodiversity (including interactions with nonnative species); and future climate change and human population growth. There was 75% congruence between areas of highest conservation priority for different aspects of biodiversity, suggesting that conservation efforts can concurrently achieve strong complementarity among all types of diversity. However, sizable fractions of the landscape were incongruent across conservation priorities for different diversity scenarios, underscoring the importance of considering multiple dimensions of biodiversity and highlighting catchments that contribute disproportionately to taxonomic, functional, and phylogenetic diversity in the region. Regions of projected human population growth were not concordant with conservation priorities; however, higher human population abundance will likely have indirect effects on native biodiversity by increasing demand for water. This will come in direct conflict with projected reductions in precipitation and warmer temperatures, which have substantial overlap with regions of high contemporary diversity. Native and endemic fishes in arid ecosystems are critically endangered by both current and future threats, but our results highlight the use of systematic conservation planning for the optimal allocation of limited resources that incorporates multiple and complementary conservation values describing taxonomic, functional, and phylogenetic diversity.
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Determinants of Habitat Selection by Hatchling Australian Freshwater Crocodiles
Somaweera, Ruchira; Webb, Jonathan K.; Shine, Richard
2011-01-01
Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle), most hatchling (<12-month-old) freshwater crocodiles (Crocodylus johnstoni) are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles) were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk. PMID:22163308
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Water Reserves Program. An adaptation strategy to balance water in nature
NASA Astrophysics Data System (ADS)
Lopez Perez, M.; Barrios, E.; Salinas-Rodriguez, S.; Wickel, B.; Villon, R. A.
2013-05-01
Freshwater ecosystems occupy approximately 1% of the earth's surface yet possess about 12% of all known animal species. By virtue of their position in the landscape they connect terrestrial and coastal marine biomes and provide and sustain ecosystem services vital to the health and persistence of human communities. These services include the supply of water for food production, urban and ind ustrial consumption, among others. Over the past century many freshwater ecosystems around the world have been heavily modified or lost due to the alteration of flow regimes (e.g. due to damming, canalization, diversion, over-abstraction). The synergistic impacts of land use change, changes in flows, chemical deterioration, and climate change have left many systems and their species very little room to adjust to change, while future projections indicate a steady increase in water demand for food and energy production and water supply to suit the needs of a growing world population. In Mexico, the focus has been to secure water for human development and maximize economic growth, which has resulted in allocation of water beyond available amounts. As a consequence episodic water scarcity severely constrains freshwater ecosystems and the services they provide. Climatic change and variability are presenting serious challenges to a country that already is experiencing serious strain on its water resources. However, freshwater ecosystems are recognized by law as legitimate user of water, and mandate a flow allocation for the environment ("water reserve" or "environmental flows"). Based on this legal provision the Mexican government through the National Water Commission (Conagua), with support of the Alliance WWF - Fundación Gonzalo Río Arronte, and the Interamerican Development Bank, has launched a national program to identify and implement "water reserves": basins where environmental flows will be secured and allocated and where the flow regime is then protected before over-allocation takes place. The strategy is to identify and protect basins with an availability of water that is close to their natural flow regime and that also have a high conservation value (based on prior national conservation priority definitions such as protected areas, and biodiversity conservation gap analyses) in order to implement legal restrictions on water resource development. With such protection, these systems will be best positioned to adjust and respond to water shortages, and regime shifts. To date, 189 basins around the country were identified as potential water reserves. The next step will be the nomination of these water reserves to be integrated in the National Water Reserves Program. This program forms the core of the official Mexican government adaptation strategy towards climate prepared water management, which recognizes that water reserves are the buffer society needs to face uncertainty, and reduce water scarcity risk. The development of activities that alter the natural flow regime such as dams and levees are closely examined, and would potentially be restricted.
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Ecological and evolutionary patterns of freshwater maturation in Pacific and Atlantic salmonines
Sloat, Matthew R.; Fraser, Dylan J.; Dunham, Jason B.; Falke, Jeffery A.; Jordan, Chris E.; McMillan, John R.; Ohms, Haley A.
2014-01-01
Reproductive tactics and migratory strategies in Pacific and Atlantic salmonines are inextricably linked through the effects of migration (or lack thereof) on age and size at maturity. In this review, we focus on the ecological and evolutionary patterns of freshwater maturation in salmonines, a key process resulting in the diversification of their life histories. We demonstrate that the energetics of maturation and reproduction provides a unifying theme for understanding both the proximate and ultimate causes of variation in reproductive schedules among species, populations, and the sexes. We use probabilistic maturation reaction norms to illustrate how variation in individual condition, in terms of body size, growth rate, and lipid storage, influences the timing of maturation. This useful framework integrates both genetic and environmental contributions to conditional strategies for maturation and, in doing so, demonstrates how flexible life histories can be both heritable and subject to strong environmental influences. We review evidence that the propensity for freshwater maturation in partially anadromous species is predictable across environmental gradients at geographic and local spatial scales. We note that growth is commonly associated with the propensity for freshwater maturation, but that life-history responses to changes in growth caused by temperature may be strikingly different than changes caused by differences in food availability. We conclude by exploring how contemporary management actions can constrain or promote the diversity of maturation phenotypes in Pacific and Atlantic salmonines and caution against underestimating the role of freshwater maturing forms in maintaining the resiliency of these iconic species.
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Ghylin, Trevor W; Garcia, Sarahi L; Moya, Francisco; Oyserman, Ben O; Schwientek, Patrick; Forest, Katrina T; Mutschler, James; Dwulit-Smith, Jeffrey; Chan, Leong-Keat; Martinez-Garcia, Manuel; Sczyrba, Alexander; Stepanauskas, Ramunas; Grossart, Hans-Peter; Woyke, Tanja; Warnecke, Falk; Malmstrom, Rex; Bertilsson, Stefan; McMahon, Katherine D
2014-12-01
Members of the acI lineage of Actinobacteria are the most abundant microorganisms in most freshwater lakes; however, our understanding of the keys to their success and their role in carbon and nutrient cycling in freshwater systems has been hampered by the lack of pure cultures and genomes. We obtained draft genome assemblies from 11 single cells representing three acI tribes (acI-A1, acI-A7, acI-B1) from four temperate lakes in the United States and Europe. Comparative analysis of acI SAGs and other available freshwater bacterial genomes showed that acI has more gene content directed toward carbohydrate acquisition as compared to Polynucleobacter and LD12 Alphaproteobacteria, which seem to specialize more on carboxylic acids. The acI genomes contain actinorhodopsin as well as some genes involved in anaplerotic carbon fixation indicating the capacity to supplement their known heterotrophic lifestyle. Genome-level differences between the acI-A and acI-B clades suggest specialization at the clade level for carbon substrate acquisition. Overall, the acI genomes appear to be highly streamlined versions of Actinobacteria that include some genes allowing it to take advantage of sunlight and N-rich organic compounds such as polyamines, di- and oligopeptides, branched-chain amino acids and cyanophycin. This work significantly expands the known metabolic potential of the cosmopolitan freshwater acI lineage and its ecological and genetic traits.
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Anthropogenic climate change has altered primary productivity in Lake Superior
O'Beirne, M. D.; Werne, J. P.; Hecky, R. E.; Johnson, T. C.; Katsev, S.; Reavie, E. D.
2017-01-01
Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems. PMID:28598413
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Increasing human pressure on freshwater resources threatens sustainability at the global scale
NASA Astrophysics Data System (ADS)
Montanari, A.; Ceola, S.; Laio, F.
2017-12-01
Freshwater resources overexploitation and climate change are major threats to global sustainability and development in the XXI century, but nevertheless a global assessment of water threats evolution in time is still lacking. Here we demonstrate that nightlights are a good proxy for human pressure and investigate how it evolved from 1992 to 2013 in 2'148 major river basins. Globally, we find that human pressure positively evolved in the study period (1.8% increase per year as a global average), threatening future sustainability worldwide. The most critical conditions for sustainability are found within the equatorial area, showing markedly positive human pressure yearly trends (3.5% ± 2.2%). The results highlight that water threats are spreading worldwide and call for an urgent strategy to mitigate water overexploitation and related hazards to ecosystems and human security.
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Science, society, and the coastal groundwater squeeze
NASA Astrophysics Data System (ADS)
Michael, Holly A.; Post, Vincent E. A.; Wilson, Alicia M.; Werner, Adrian D.
2017-04-01
Coastal zones encompass the complex interface between land and sea. Understanding how water and solutes move within and across this interface is essential for managing resources for society. The increasingly dense human occupation of coastal zones disrupts natural groundwater flow patterns and degrades freshwater resources by both overuse and pollution. This pressure results in a "coastal groundwater squeeze," where the thin veneers of potable freshwater are threatened by contaminant sources at the land surface and saline groundwater at depth. Scientific advances in the field of coastal hydrogeology have enabled responsible management of water resources and protection of important ecosystems. To address the problems of the future, we must continue to make scientific advances, and groundwater hydrology needs to be firmly embedded in integrated coastal zone management. This will require interdisciplinary scientific collaboration, open communication between scientists and the public, and strong partnerships with policymakers.
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Anthropogenic climate change has altered primary productivity in Lake Superior.
O'Beirne, M D; Werne, J P; Hecky, R E; Johnson, T C; Katsev, S; Reavie, E D
2017-06-09
Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.
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Feeding type and development drive the ingestion of microplastics by freshwater invertebrates.
Scherer, Christian; Brennholt, Nicole; Reifferscheid, Georg; Wagner, Martin
2017-12-05
Microscopic plastic items (microplastics) are ubiquitously present in aquatic ecosystems. With decreasing size their availability and potential to accumulate throughout food webs increase. However, little is known on the uptake of microplastics by freshwater invertebrates. To address this, we exposed species with different feeding strategies to 1, 10 and 90 µm fluorescent polystyrene spheres (3-3 000 particles mL -1 ). Additionally, we investigated how developmental stages and a co-exposure to natural particles (e.g., food) modulate microplastic ingestion. All species ingested microplastics in a concentration-dependent manner with Daphnia magna consuming up to 6 180 particles h -1 , followed by Chironomus riparius (226 particles h -1 ), Physella acuta (118 particles h -1 ), Gammarus pulex (10 particles h -1 ) and Lumbriculus variegatus (8 particles h -1 ). D. magna did not ingest 90 µm microplastics whereas the other species preferred larger microplastics over 1 µm in size. In C. riparius and D. magna, size preference depended on the life stage with larger specimens ingesting more and larger microplastics. The presence of natural particles generally reduced the microplastics uptake. Our results demonstrate that freshwater invertebrates have the capacity to ingest microplastics. However, the quantity of uptake depends on their feeding type and morphology as well as on the availability of microplastics.
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Storlazzi, Curt; Gingerich, Stephen B.; van Dongeren, Ap; Cheriton, Olivia; Swarzenski, Peter W.; Quataert, Ellen; Voss, Clifford I.; Field, Donald W.; Annamalai, Hariharasubramanian; Piniak, Greg A.; McCall, Robert T.
2018-01-01
Sea levels are rising, with the highest rates in the tropics, where thousands of low-lying coral atoll islands are located. Most studies on the resilience of these islands to sea-level rise have projected that they will experience minimal inundation impacts until at least the end of the 21st century. However, these have not taken into account the additional hazard of wave-driven overwash or its impact on freshwater availability. We project the impact of sea-level rise and wave-driven flooding on atoll infrastructure and freshwater availability under a variety of climate change scenarios. We show that, on the basis of current greenhouse gas emission rates, the nonlinear interactions between sea-level rise and wave dynamics over reefs will lead to the annual wave-driven overwash of most atoll islands by the mid-21st century. This annual flooding will result in the islands becoming uninhabitable because of frequent damage to infrastructure and the inability of their freshwater aquifers to recover between overwash events. This study provides critical information for understanding the timing and magnitude of climate change impacts on atoll islands that will result in significant, unavoidable geopolitical issues if it becomes necessary to abandon and relocate low-lying island states.
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Storlazzi, Curt D; Gingerich, Stephen B; van Dongeren, Ap; Cheriton, Olivia M; Swarzenski, Peter W; Quataert, Ellen; Voss, Clifford I; Field, Donald W; Annamalai, Hariharasubramanian; Piniak, Greg A; McCall, Robert
2018-04-01
Sea levels are rising, with the highest rates in the tropics, where thousands of low-lying coral atoll islands are located. Most studies on the resilience of these islands to sea-level rise have projected that they will experience minimal inundation impacts until at least the end of the 21st century. However, these have not taken into account the additional hazard of wave-driven overwash or its impact on freshwater availability. We project the impact of sea-level rise and wave-driven flooding on atoll infrastructure and freshwater availability under a variety of climate change scenarios. We show that, on the basis of current greenhouse gas emission rates, the nonlinear interactions between sea-level rise and wave dynamics over reefs will lead to the annual wave-driven overwash of most atoll islands by the mid-21st century. This annual flooding will result in the islands becoming uninhabitable because of frequent damage to infrastructure and the inability of their freshwater aquifers to recover between overwash events. This study provides critical information for understanding the timing and magnitude of climate change impacts on atoll islands that will result in significant, unavoidable geopolitical issues if it becomes necessary to abandon and relocate low-lying island states.
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2018-01-01
Sea levels are rising, with the highest rates in the tropics, where thousands of low-lying coral atoll islands are located. Most studies on the resilience of these islands to sea-level rise have projected that they will experience minimal inundation impacts until at least the end of the 21st century. However, these have not taken into account the additional hazard of wave-driven overwash or its impact on freshwater availability. We project the impact of sea-level rise and wave-driven flooding on atoll infrastructure and freshwater availability under a variety of climate change scenarios. We show that, on the basis of current greenhouse gas emission rates, the nonlinear interactions between sea-level rise and wave dynamics over reefs will lead to the annual wave-driven overwash of most atoll islands by the mid-21st century. This annual flooding will result in the islands becoming uninhabitable because of frequent damage to infrastructure and the inability of their freshwater aquifers to recover between overwash events. This study provides critical information for understanding the timing and magnitude of climate change impacts on atoll islands that will result in significant, unavoidable geopolitical issues if it becomes necessary to abandon and relocate low-lying island states. PMID:29707635
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Development of a Coastal Drought Index Using Salinity Data
NASA Astrophysics Data System (ADS)
Conrads, P. A.; Darby, L. S.
2014-12-01
The freshwater-saltwater interface in surface-water bodies along the coast is an important factor in the ecological and socio-economic dynamics of coastal communities. It influences community composition in freshwater and saltwater ecosystems, determines fisheries spawning habitat, and controls freshwater availability for municipal and industrial water intakes. These dynamics may be affected by coastal drought through changes in Vibrio bacteria impacts on shellfish harvesting and occurrence of wound infection, fish kills, harmful algal blooms, hypoxia, and beach closures. There are many definitions of drought, with most describing a decline in precipitation having negative impacts on water supply and agriculture. Four general types of drought are recognized: hydrological, agricultural, meteorological, and socio-economic. Indices have been developed for these drought types incorporating data such as rainfall, streamflow, soil moisture, groundwater levels, and snow pack. These indices were developed for upland areas and may not be appropriate for characterizing drought in coastal areas. Because of the uniqueness of drought impacts on coastal ecosystems, a need exists to develop a coastal drought index. The availability of real-time and historical salinity datasets provides an opportunity to develop a salinity-based coastal drought index. The challenge of characterizing salinity dynamics in response to drought is excluding responses attributable to occasional saltwater intrusion events. Our approach to develop a coastal drought index modified the Standardized Precipitation Index and applied it to sites in South Carolina and Georgia, USA. Coastal drought indices characterizing 1-, 3-, 6-, 9-, and12-month drought conditions were developed. Evaluation of the coastal drought index indicates that it can be used for different estuary types, for comparison between estuaries, and as an index for wet conditions (high freshwater inflow) in addition to drought conditions.
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NASA Astrophysics Data System (ADS)
Pietroniro, Al; Korhonen, Johanna; Looser, Ulrich; Hardardóttir, Jórunn; Johnsrud, Morten; Vuglinsky, Valery; Gustafsson, David; Lins, Harry F.; Conaway, Jeffrey S.; Lammers, Richard; Stewart, Bruce; Abrate, Tommaso; Pilon, Paul; Sighomnou, Daniel; Arheimer, Berit
2015-04-01
The Arctic region is an important regulating component of the global climate system, and is also experiencing a considerable change during recent decades. More than 10% of world's river-runoff flows to the Arctic Ocean and there is evidence of changes in its fresh-water balance. However, about 30% of the Arctic basin is still ungauged, with differing monitoring practices and data availability from the countries in the region. A consistent system for monitoring and sharing of hydrological information throughout the Arctic region is thus of highest interest for further studies and monitoring of the freshwater flux to the Arctic Ocean. The purpose of the Arctic-HYCOS project is to allow for collection and sharing of hydrological data. Preliminary 616 stations were identified with long-term daily discharge data available, and around 250 of these already provide online available data in near real time. This large sample will be used in the following scientific analysis: 1) to evaluate freshwater flux to the Arctic Ocean and Seas, 2) to monitor changes and enhance understanding of the hydrological regime and 3) to estimate flows in ungauged regions and develop models for enhanced hydrological prediction in the Arctic region. The project is intended as a component of the WMO (World Meteorological Organization) WHYCOS (World Hydrological Cycle Observing System) initiative, covering the area of the expansive transnational Arctic basin with participation from Canada, Denmark, Finland, Iceland, Norway, Russian Federation, Sweden and United States of America. The overall objective is to regularly collect, manage and share high quality data from a defined basic network of hydrological stations in the Arctic basin. The project focus on collecting data on discharge and possibly sediment transport and temperature. Data should be provisional in near-real time if available, whereas time-series of historical data should be provided once quality assurance has been completed. The initial stages of the project will focus on collecting data on discharge and revise station selection criteria. For monitoring freshwater flow to oceans, stations close to the mouths of rivers and immediately inland for back-up purposes will be preferred. For studies of change emphasis is placed on hydrological regime stations located in headwaters small sub-catchments, including pristine basins. Stations outside the Arctic Ocean basin, such as at the mouth of the Yukon River, Baltic Sea and Hudson Bay, can also be considered to allow a better understanding of hydrological processes occurring in the general region. Countries shall facilitate, to the extent possible, access to their data currently published online, and also access to those not yet regularly published on the web. At a later stage data exchange standards such as WaterML2.0 will be implemented. The project will also perform pan-Arctic hydrological modelling (geo-statistical, deterministic and probabilistic methods) for the assessment and integration of observational and modelled data to improve estimates of ungauged discharge and the overall estimates of freshwater flux to the Arctic Ocean, as well as understanding of hydrological processes.
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Human Freshwater Demand for Economic Activity and Ecosystems in Taiwan
NASA Astrophysics Data System (ADS)
Ferng, Jiun-Jiun
2007-12-01
Freshwater is necessary to economic activity, and humans depend on goods and services generated by water-dependent ecosystems. However, national freshwater management usually focuses on direct use of domestic freshwater. With an increasing scarcity of freshwater, attention has turned to two indirect uses of freshwater by humans. The first indirect use is freshwater used by foreign countries when producing products for export. The second use is freshwater required by local ecosystems: human survival and development depend on goods and services generated in these ecosystems. This work adopted Taiwan as a case study. In addition to two widely recognized ecosystem freshwater demands, evapotranspiration and reversed river flow, this study suggests that freshwater is a constituent of some abiotic components, such as groundwater in aquifers, because excessive withdrawal has already caused significant land subsidence in Taiwan. Moreover, the estimated results show that Taiwan’s net imports of freshwater through trade amounts to approximately 25% of its total freshwater use for economic production. Integrating industrial policy, trade policy, and national freshwater management is a useful approach for developing strategies to limit the growing use of freshwater in Taiwan. Policy implications are then developed by further analyzing withdrawal sources of freshwater (domestic and foreign) for supporting economic production in Taiwan and identifying the factors (domestic final demand and export) driving freshwater-intensive products.
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NASA Astrophysics Data System (ADS)
Hotchkiss, E. R.
2017-12-01
Freshwater biological processes can alter the quantity and quality of organic carbon (OC) inputs from land before they are transported downstream, but the relative role of hydrologic transport and in-stream processing is still not well quantified at the scale of fluvial networks. Despite much research on the role of biology and hydrology in governing the form and fate of C in inland waters, conclusions about the function of freshwater ecosystems in modifying OC still largely depend on where we draw our ecosystem boundaries, i.e., the spatial scale of measurements used to assess OC transformations. Here I review freshwater OC uptake rates derived from bioassay incubations, synoptic modeling, reach-scale experiments, and ecosystem OC spiraling estimates. Median OC uptake velocities from standard bioassay incubations (0.02 m/d) and synoptic modeling (0.04 m/d) are 1-2 orders of magnitude lower than reach-scale experimental DOC additions and ecosystem OC spiraling estimates (2.2 and 0.27 m/d, respectively) in streams and rivers. Together, ecosystem metabolism and OC fluxes can be used to estimate the distance OC travels before being consumed and respired as CO2 through biological processes (i.e., OC spiraling), allowing for a more mechanistic understanding of the role of ecosystem processes and hydrologic fluxes in modifying downstream OC transport. Beyond the reach scale, data from stream network and stream-lake-river modeling simulations show how we may use linked sampling sites within networks to better understand the integrated sources and fate of OC in freshwaters. We currently underestimate the role of upstream processes in contributing to downstream fluxes: moving from single-ecosystem comparisons to linked-ecosystem simulations increases the contribution of in situ OC processing to CO2 emissions from 30% to >40%. Insights from literature reviews, ecosystem process measurements, and model simulations provide a framework for future considerations of integrated C transport, transformations, and fate when scaling patterns and processes in inland waters.
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Use of geoelectrical methods in groundwater pollution surveys in a coastal environment
NASA Astrophysics Data System (ADS)
Frohlich, Reinhard K.; Urish, Daniel W.; Fuller, James; O'Reilly, Mary
1994-08-01
The pollution of coastal aquifers by old landfills can contaminate valuable and scarce water resources in the freshwater lens utilized seasonably by overcrowded communities. The pollutants will ultimately flow into the sea where they may also cause a coastal water pollution problem. We have detected pollution in the freshwater lens from a sanitary landfill near Provincetown, Cape Cod, using the geoelectrical resistivity method. This survey included Schlumberger geoelectrical depth soundings and a horizontal geoelectrical profile using the Wenner configuration. The geoelectrical survey was conducted at a site along Highway 6 where it passes the coastal town of Provincetown and a sanitary landfill that has been in operation since 1954. The depth soundings suggest the characteristic decrease in resistivity vs. depth from the high resistivity of the unsaturated zone to the low resistivity of the saltwater saturated zone. The freshwater lens is clearly identified by the change in slope of the steeply dipping curve of resistivity versus electrode spacing. Interpretations made using a multilayer program, GEOMATE, resulted in layer resistivities between 460 and 95 ohm·m for the freshwater lens. A comparison with well water resistivities suggests that a layer resistivity of 230 ohm·m or lower is indicative of pollution in the freshwater lens. The results of the geoelectrical depth soundings were confirmed in the Wenner horizontal profile. Both measurements suggest that the pollutants do not spread evenly as one would expect for a homogeneous and isotropic medium. Instead, a preferred channel for the flow of the pollutants is observed along a path from the landfill toward the shoreline. The depth to the saltwater/freshwater interface or, more specifically, to the low resistivity-high resistivity interface appears to be shallow where the freshwater lens is polluted. This was confirmed by pore water well samples that were highly mineralized. The equilibrium postulated by the Ghyben-Herzberg relation appears to be disturbed in the area of aquifer pollution. This rise in the conductivity boundary is caused by the highly mineralized bottom of the contaminant plume that submerges into the saltwater saturated zone. In the area of high freshwater pollution the groundwater can be subdivided into three layers that show a decrease in resistivity with depth. The formation factor, F, defined as the ratio of bulk aquifer resistivity to pore water resistivity, shows unusually high values between 10 and 12. These high values are unexpected for an unconsolidated sand. Pollution residues are suspected to clog the pores and thus to increase the resistivity. It is possible that iron-oxidizing bacteria and the precipitation of dissolved iron or organic pollutants are the cause of the high values of F. If proven correct, these interesting possibilities could lead to future new applications of the geoelectrical resistivity method in contaminant hydroloy.
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Use of geoelectrical methods in groundwater pollution surveys in a coastal environment
Frohlich, R.K.; Urish, D.W.; Fuller, J.; O'Reilly, M.
1994-01-01
The pollution of coastal aquifers by old landfills can contaminate valuable and scarce water resources in the freshwater lens utilized seasonably by overcrowded communities. The pollutants will ultimately flow into the sea where they may also cause a coastal water pollution problem. We have detected pollution in the freshwater lens from a sanitary landfill near Provincetown, Cape Cod, using the geoelectrical resistivity method. This survey included Schlumberger geoelectrical depth soundings and a horizontal geoelectrical profile using the Wenner configuration. The geoelectrical survey was conducted at a site along Highway 6 where it passes the coastal town of Provincetown and a sanitary landfill that has been in operation since 1954. The depth soundings suggest the characteristic decrease in resistivity vs. depth from the high resistivity of the unsaturated zone to the low resistivity of the saltwater saturated zone. The freshwater lens is clearly identified by the change in slope of the steeply dipping curve of resistivity versus electrode spacing. Interpretations made using a multilayer program, Geomate, resulted in layer resistivities between 460 and 95 ohm?m for the freshwater lens. A comparison with well water resistivities suggests that a layer resistivity of 230 ohm?m or lower is indicative of pollution in the freshwater lens. The results of the geoelectrical depth soundings were confirmed in the Wenner horizontal profile. Both measurements suggest that the pollutants do not spread evenly as one would expect for a homogeneous and isotropic medium. Instead, a preferred channel for the flow of the pollutants is observed along a path from the landfill toward the shoreline. The depth to the saltwater/freshwater interface or, more specifically, to the low resistivity-high resistivity interface appears to be shallow where the freshwater lens is polluted. This was confirmed by pore water well samples that were highly mineralized. The equilibrium postulated by the Ghyben-Herzberg relation appears to be disturbed in the area of aquifer pollution. This rise in the conductivity boundary is caused by the highly mineralized bottom of the contaminant plume that submerges into the saltwater saturated zone. In the area of high freshwater pollution the groundwater can be subdivided into three layers that show a decrease in resistivity with depth. The formation factor, F, defined as the ratio of bulk aquifer resistivity to pore water resistivity, shows unusually high values between 10 and 12. These high values are unexpected for an unconsolidated sand. Pollution residues are suspected to clog the pores and thus to increase the resistivity. It is possible that iron-oxidizing bacteria and the precipitation of dissolved iron or organic pollutants are the cause of the high values of F. If proven correct, these interesting possibilities could lead to future new applications of the geoelectrical resistivity method in contaminant hydroloy.
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People, pollution and pathogens - Global change impacts in mountain freshwater ecosystems.
Schmeller, Dirk S; Loyau, Adeline; Bao, Kunshan; Brack, Werner; Chatzinotas, Antonis; De Vleeschouwer, Francois; Friesen, Jan; Gandois, Laure; Hansson, Sophia V; Haver, Marilen; Le Roux, Gaël; Shen, Ji; Teisserenc, Roman; Vredenburg, Vance T
2018-05-01
Mountain catchments provide for the livelihood of more than half of humankind, and have become a key destination for tourist and recreation activities globally. Mountain ecosystems are generally considered to be less complex and less species diverse due to the harsh environmental conditions. As such, they are also more sensitive to the various impacts of the Anthropocene. For this reason, mountain regions may serve as sentinels of change and provide ideal ecosystems for studying climate and global change impacts on biodiversity. We here review different facets of anthropogenic impacts on mountain freshwater ecosystems. We put particular focus on micropollutants and their distribution and redistribution due to hydrological extremes, their direct influence on water quality and their indirect influence on ecosystem health via changes of freshwater species and their interactions. We show that those changes may drive pathogen establishment in new environments with harmful consequences for freshwater species, but also for the human population. Based on the reviewed literature, we recommend reconstructing the recent past of anthropogenic impact through sediment analyses, to focus efforts on small, but highly productive waterbodies, and to collect data on the occurrence and variability of microorganisms, biofilms, plankton species and key species, such as amphibians due to their bioindicator value for ecosystem health and water quality. The newly gained knowledge can then be used to develop a comprehensive framework of indicators to robustly inform policy and decision making on current and future risks for ecosystem health and human well-being. Copyright © 2017 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Prigge, Enno; Malzahn, Arne M.; Zumholz, Karsten; Hanel, Reinhold
2012-03-01
The role of intracontinental migration patterns of European eel ( Anguilla anguilla) receives more and more recognition in both ecological studies of the European eel and possible management measures, but small-scale patterns proved to be challenging to study. We experimentally investigated the suitability of fatty acid trophic markers to elucidate the utilization of feeding habitats. Eight groups of juvenile European eels were fed on eight different diets in a freshwater recirculation system at 20°C for 56 days. Three groups were fed on freshwater diets ( Rutilus rutilus, Chironomidae larvae, and Gammarus pulex) and four groups were reared on diets of a marine origin ( Clupea harengus, Crangon crangon, Mysis spec., and Euphausia superba) and one on commercial pellets used in eel aquaculture. Fatty acid composition (FAC) of diets differed significantly with habitat. FAC of eel muscle tissue seemed to be rather insensitive to fatty acids supplied with diet, but the general pattern of lower n3:n6 and EPA:ARA ratios in freshwater prey organisms could be traced in the respective eels. Multivariate statistics of the fatty acid composition of the eels resulted in two distinct groups representing freshwater and marine treatments. Results further indicate the capability of selectively restraining certain fatty acids in eel, as e.g. the n3:n6 ratio in all treatments was <4, regardless of dietary n3:n6. In future studies on wild eel, these measures can be used to elucidate the utilization of feeding habitats of individual European eel.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Wu, M.; Peng, J.; NE)
2011-02-24
Freshwater consumption for electricity generation is projected to increase dramatically in the next couple of decades in the United States. The increased demand is likely to further strain freshwater resources in regions where water has already become scarce. Meanwhile, the automotive industry has stepped up its research, development, and deployment efforts on electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs). Large-scale, escalated production of EVs and PHEVs nationwide would require increased electricity production, and so meeting the water demand becomes an even greater challenge. The goal of this study is to provide a baseline assessment of freshwater use inmore » electricity generation in the United States and at the state level. Freshwater withdrawal and consumption requirements for power generated from fossil, nonfossil, and renewable sources via various technologies and by use of different cooling systems are examined. A data inventory has been developed that compiles data from government statistics, reports, and literature issued by major research institutes. A spreadsheet-based model has been developed to conduct the estimates by means of a transparent and interactive process. The model further allows us to project future water withdrawal and consumption in electricity production under the forecasted increases in demand. This tool is intended to provide decision makers with the means to make a quick comparison among various fuel, technology, and cooling system options. The model output can be used to address water resource sustainability when considering new projects or expansion of existing plants.« less
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Lopes-Lima, Manuel; Froufe, Elsa; Do, Van Tu; Ghamizi, Mohamed; Mock, Karen E; Kebapçı, Ümit; Klishko, Olga; Kovitvadhi, Satit; Kovitvadhi, Uthaiwan; Paulo, Octávio S; Pfeiffer, John M; Raley, Morgan; Riccardi, Nicoletta; Şereflişan, Hülya; Sousa, Ronaldo; Teixeira, Amílcar; Varandas, Simone; Wu, Xiaoping; Zanatta, David T; Zieritz, Alexandra; Bogan, Arthur E
2017-01-01
Freshwater mussels of the order Unionida are key elements of freshwater habitats and are responsible for important ecological functions and services. Unfortunately, these bivalves are among the most threatened freshwater taxa in the world. However, conservation planning and management are hindered by taxonomic problems and a lack of detailed ecological data. This highlights the urgent need for advances in the areas of systematics and evolutionary relationships within the Unionida. This study presents the most comprehensive phylogeny to date of the larger Unionida family, i.e., the Unionidae. The phylogeny is based on a combined dataset of 1032bp (COI+28S) of 70 species in 46 genera, with 7 of this genera being sequenced for the first time. The resulting phylogeny divided the Unionidae into 6 supported subfamilies and 18 tribes, three of which are here named for the first time (i.e., Chamberlainiini nomen novum, Cristariini nomen novum and Lanceolariini nomen novum). Molecular analyses were complemented by investigations of selected morphological, anatomical and behavioral characters used in traditional phylogenetic studies. No single morphological, anatomical or behavioral character was diagnostic at the subfamily level and few were useful at the tribe level. However, within subfamilies, many tribes can be recognized based on a subset of these characters. The geographical distribution of each of the subfamilies and tribes is also presented. The present study provides important advances in the systematics of these extraordinary taxa with implications for future ecological and conservation studies. Copyright © 2016 Elsevier Inc. All rights reserved.
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Long Term Large Scale river nutrient changes across the UK
NASA Astrophysics Data System (ADS)
Bell, Victoria; Naden, Pam; Tipping, Ed; Davies, Helen; Davies, Jessica; Dragosits, Ulli; Muhammed, Shibu; Quinton, John; Stuart, Marianne; Whitmore, Andy; Wu, Lianhai
2017-04-01
During recent decades and centuries, pools and fluxes of Carbon, Nitrogen and Phosphorus (C, N and P) in UK rivers and ecosystems have been transformed by the spread and fertiliser-based intensification of agriculture (necessary to sustain human populations), by atmospheric pollution, by human waste (rising in line with population growth), and now by climate change. The principal objective of the UK's NERC-funded Macronutrients LTLS research project has been to account for observable terrestrial and aquatic pools, concentrations and fluxes of C, N and P on the basis of past inputs, biotic and abiotic interactions, and transport processes. More specifically, over the last 200 years, what have been the temporal responses of plant and soil nutrient pools in different UK catchments to nutrient enrichment, and what have been the consequent effects on nutrient transfers from land to the atmosphere, freshwaters and estuaries? The work described here addresses the second question by providing an integrated quantitative description of the interlinked land and water pools and annual fluxes of C, N and P for UK catchments over time. A national-scale modelling environment has been developed, combining simple physically-based gridded models that can be parameterised using recent observations before application to long timescales. The LTLS Integrated Model (LTLS-IM) uses readily-available driving data (climate, land-use, nutrient inputs, topography), and model estimates of both terrestrial and freshwater nutrient loads have been compared with measurements from sites across the UK. Here, the focus is on the freshwater nutrient component of the LTLS-IM, but the terrestrial nutrient inputs required for this are provided by models of nutrient processes in semi-natural and agricultural systems, and from simple models of nutrients arising from human waste. In the freshwater model, lateral routing of dissolved and particulate nutrients and within-river processing such as denitrification, decomposition and chlorophyll growth are undertaken, and the effects of groundwater storage and processes in lakes connected to the river network can be included. Following assessment against observations of terrestrial and nutrient fluxes in rivers across the UK, the LTLS-IM has been run nationally for 200 years (1800 to 2010), and the work presented here provides, for the first time, national, regional or catchment estimates of the origins and trends in riverine nutrients in the period following the industrial revolution. Ongoing work is now exploring the effects of future climate, waste water treatment and land-management scenarios on water quality, and the effects of nutrient enrichment on the development of eutrophication in rivers.
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Projected freshwater withdrawals in the United States under a changing climate
Thomas C. Brown; Romano Foti; Jorge A. Ramirez
2013-01-01
Relying on the U.S. Geological Survey water use data for the period 1960 2005, this paper summarizes past water use and then projects future water use based on the trends in water use efficiency and major drivers of water use. Water use efficiency has improved in most sectors. Over the past 45 years, withdrawals in industry and at thermoelectric plants have steadily...
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Are wildland watersheds safest and best?
Lawrence S. Hamilton
2007-01-01
The 2003 International Year of Freshwater highlighted the critical current and future scenario, on a global scale, of scarcity of adequate waterâthe essential need for all living things. About 40 percent of the worldâs population currently have moderate to high water stress, and it is estimated that by 2025 about two-thirds of the world will live in areas facing such...
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NASA Astrophysics Data System (ADS)
Moran, E. H.; Tindall, J. A.; Campbell, A. A.
2010-12-01
ABSTRACT Energy and water security and sustainability have become a national and global priority. The continued security and economic health of any country depends on a sustainable supply of both energy and water because these two critical natural resources are inexorably linked. The production of energy requires large volumes of water while the treatment and distribution of water is equally dependent upon readily available, low-cost energy. In the U.S. and other countries, irrigated agriculture and thermoelectric generation withdrawals of fresh water are approximately equal however; they are growing due to increasing population. Within the U.S. electricity production requires about 190,000 million gallons of freshwater per day, accounting for over 40 percent of all daily freshwater withdrawals in the U.S. The indirect use of water (home lighting and electric appliances) is approximately equal to its direct use (watering lawns and taking showers). Current trends of water use and availability suggest that meeting future water and energy demands to support continued economic global development will require improved utilization and management of both energy and water resources. Primary concerns include: (1) Increasing populations require more food and energy; this may cause direct competition between the two largest water users for limited water resources (energy and agriculture); (2) Population growth and economic expansion projections indicate the U.S. alone will require an additional 393,000 MW of new generating capacity (equivalent to about 1,000 new 400 MW plants) by the year 2020 - other countries particularly India and China have similar trends; and (3) Potential environmental and ecological restrictions on the use of water for power generation such as the restrictions on cooling water withdrawals and cooling water use for nuclear power plants to protect aquatic species and habitat and the environment may reduce usable supplies. The U.S. and other Nation's abilities to meet the increasing demand for affordable water and energy are being seriously challenged by these emerging issues. This research presents potential solutions for security and sustainability of these systems, which are a pressing global priority.
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Effects of elevated water temperature on physiological responses in adult freshwater mussels
Ganser, Alissa M.; Newton, Teresa J.; Haro, Roger J.
2015-01-01
These data suggest that elevated temperatures can alter metabolic rates in native mussels and may decrease the amount of energy that is available for key biological processes, such as survival, growth and reproduction.
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Seasonal variation in natural recharge of coastal aquifers
NASA Astrophysics Data System (ADS)
Mollema, Pauline N.; Antonellini, Marco
2013-06-01
Many coastal zones around the world have irregular precipitation throughout the year. This results in discontinuous natural recharge of coastal aquifers, which affects the size of freshwater lenses present in sandy deposits. Temperature data for the period 1960-1990 from LocClim (local climate estimator) and those obtained from the Intergovernmental Panel on Climate Change (IPCC) SRES A1b scenario for 2070-2100, have been used to calculate the potential evapotranspiration with the Thornthwaite method. Potential recharge (difference between precipitation and potential evapotranspiration) was defined at 12 locations: Ameland (The Netherlands), Auckland and Wellington (New Zealand); Hong Kong (China); Ravenna (Italy), Mekong (Vietnam), Mumbai (India), New Jersey (USA), Nile Delta (Egypt), Kobe and Tokyo (Japan), and Singapore. The influence of variable/discontinuous recharge on the size of freshwater lenses was simulated with the SEAWAT model. The discrepancy between models with continuous and with discontinuous recharge is relatively small in areas where the total annual recharge is low (258-616 mm/year); but in places with Monsoon-dominated climate (e.g. Mumbai, with recharge up to 1,686 mm/year), the difference in freshwater-lens thickness between the discontinuous and the continuous model is larger (up to 5 m) and thus important to consider in numerical models that estimate freshwater availability.
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Shellenbarger, G.G.; Schoellhamer, D.H.
2011-01-01
The U.S. Geological Survey and other federal and state agencies have been collecting continuous temperature and salinity data, two critical estuarine habitat variables, throughout San Francisco estuary for over two decades. Although this dynamic, highly variable system has been well studied, many questions remain relating to the effects of freshwater inflow and other physical and biological linkages. This study examines up to 20 years of publically available, continuous temperature and salinity data from 10 different San Francisco Bay stations to identify trends in temperature and salinity and quantify the salinityfreshwater inflow relationship. Several trends in the salinity and temperature records were identified, although the high degree of daily and interannual variability confounds the analysis. In addition, freshwater inflow to the estuary has a range of effects on salinity from -0.0020 to -0.0096 (m3 s-1) -1 discharge, depending on location in the estuary and the timescale of analyzed data. Finally, we documented that changes in freshwater inflow to the estuary that are within the range of typical management actions can affect bay-wide salinities by 0.61.4. This study reinforces the idea that multidecadal records are needed to identify trends from decadal changes in water management and climate and, therefore, are extremely valuable. ?? 2011 Coastal Education & Research Foundation.
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Parasites of marine, freshwater and farmed fishes of Portugal: a review.
Eiras, Jorge da Costa
2016-01-01
An extensive literature review is made of the parasites in marine and freshwater fish in mainland Portugal, the Portuguese archipelagos of the Azores and Madeira, as well as in farmed fish. The host(s) of each parasite species, its location in the host, site of capture of the host, whenever possible, and all the available bibliographic references are described. The economic importance of some parasites and the zoonotic relevance of some parasitic forms are discussed. A general overview of the data is provided, and some research lines are suggested in order to increase and complement the current body of knowledge about the parasites of fish from Portugal.
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Molecular assessment of bacterial pathogens - a contribution to drinking water safety.
Brettar, Ingrid; Höfle, Manfred G
2008-06-01
Human bacterial pathogens are considered as an increasing threat to drinking water supplies worldwide because of the growing demand of high-quality drinking water and the decreasing quality and quantity of available raw water. Moreover, a negative impact of climate change on freshwater resources is expected. Recent advances in molecular detection technologies for bacterial pathogens in drinking water bear the promise in improving the safety of drinking water supplies by precise detection and identification of the pathogens. More importantly, the array of molecular approaches allows understanding details of infection routes of waterborne diseases, the effects of changes in drinking water treatment, and management of freshwater resources.
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A bioaccumulation bioassay for freshwater sediments
Mac, Michael J.; Noguchi, George E.; Hesselberg, Robert J.; Edsall, Carol C.; Shoesmith, John A.; Bowker, James D.
1990-01-01
A laboratory bioassay is described for determining the bioavailability of contaminants from freshwater sediments. The bioassay consists of 10-d exposures to whole sediments under flow-through conditions. After testing five species, the fathead minnow (Pimephales promelas) and the earthworm (Lubricus terrestris) were recommended for use in the test. When the availability of polychlorinated biphenyls (PCBs), Hg and Zn from Great Lakes sediments was examined in laboratory exposures, only the PCBs were accumulated. A field validation study demonstrated that the magnitude of accumulation in laboratory exposures was similar to that in organisms caged in the field. A protocol is recommended for using the test as a standardized bioaccumulation bioassay.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Hejazi, Mohamad I.; Edmonds, James A.; Clarke, Leon E.
2014-01-01
Water scarcity conditions over the 21st century both globally and regionally are assessed in the context of climate change, by estimating both water availability and water demand within the Global Change Assessment Model (GCAM), a leading community integrated assessment model of energy, agriculture, climate, and water. To quantify changes in future water availability, a new gridded water-balance global hydrologic model – namely, the Global Water Availability Model (GWAM) – is developed and evaluated. Global water demands for six major demand sectors (irrigation, livestock, domestic, electricity generation, primary energy production, and manufacturing) are modeled in GCAM at the regional scale (14more » geopolitical regions, 151 sub-regions) and then spatially downscaled to 0.5 o x 0.5o resolution to match the scale of GWAM. Using a baseline scenario (i.e., no climate change mitigation policy) with radiative forcing reaching 8.8 W/m2 (equivalent to the SRES A1Fi emission scenario) and a global population of 14 billion by 2095, global annual water demand grows from about 9% of total annual renewable freshwater in 2005 to about 32% by 2095. This results in almost half of the world population living under extreme water scarcity by the end of the 21st century. Regionally, the demand for water exceeds the amount of water availability in two GCAM regions, the Middle East and India. Additionally, in years 2050 and 2095, 20% and 27% of the global population, respectively, is projected to live in areas (grid cells) that will experience greater water demands than the amount of available water in a year (i.e., the water scarcity index (WSI) > 1.0). This study implies an increasingly prominent role for water in future human decisions, and highlights the importance of including water in integrated assessment of global change.« less
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Boleydei, Hamid; Mirghaffari, Nourollah; Farhadian, Omidvar
2018-05-15
Efficiency of a biosorbent prepared from the green macroalga Enteromorpha intestinalis biomass for decontamination of seawater and freshwater polluted by crude oil and engine spent oil was compared. The effect of different experimental conditions including contact time, pH, particle size, initial oil concentration, and biosorbent dose on the oil biosorption was studied in the batch method. The biosorbent was characterized by CHNOS, FTIR, and SEM analysis. The experimental data were well fitted to the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. Based on the obtained results, the adsorption of spent oil with higher viscosity was better than crude oil. The biosorption of oil hydrocarbons from seawater was more efficient than freshwater. The algal biomasses which are abundantly available could be effectively used as a low-cost and environmentally friendly adsorbent for remediation of oil spill in the marine environments or in the water and wastewater treatment.
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Genomes of Planktonic Acidimicrobiales: Widening Horizons for Marine Actinobacteria by Metagenomics
Mizuno, Carolina Megumi; Ghai, Rohit
2015-01-01
ABSTRACT The genomes of four novel marine Actinobacteria have been assembled from large metagenomic data sets derived from the Mediterranean deep chlorophyll maximum (DCM). These are the first marine representatives belonging to the order Acidimicrobiales and only the second group of planktonic marine Actinobacteria to be described. Their streamlined genomes and photoheterotrophic lifestyle suggest that they are planktonic, free-living microbes. A novel rhodopsin clade, acidirhodopsins, related to freshwater actinorhodopsins, was found in these organisms. Their genomes suggest a capacity to assimilate C2 compounds, some using the glyoxylate bypass and others with the ethylmalonyl-coenzyme A (CoA) pathway. They are also able to derive energy from dimethylsulfopropionate (DMSP), sulfonate, and carbon monoxide oxidation, all commonly available in the marine habitat. These organisms appear to be prevalent in the deep photic zone at or around the DCM. The presence of sister clades to the marine Acidimicrobiales in freshwater aquatic habitats provides a new example of marine-freshwater transitions with potential evolutionary insights. PMID:25670777
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Physical modeling of the effects of climate change on freshwater lenses
NASA Astrophysics Data System (ADS)
Stoeckl, L.; Houben, G.
2012-04-01
The investigation of the fragile equilibrium between fresh and saline water on oceanic islands is of major importance for a sustainable management and protection of freshwater lenses. Overexploitation will lead to salt water intrusion (up-coning), in turn causing damages or even destruction of a lens in the long term. We have performed a series of experiments on the laboratory scale to investigate and visualize processes of freshwater lenses under different boundary conditions. In addition these scenarios were numerically simulated using the finite-element model FEFLOW. Results were also compared to analytical solutions for problems regarding e.g. mean travel times of flow paths within a freshwater lens. On the laboratory scale, a cross section of an island was simulated by setting up a sand-box model (200 cm x 50 cm x 5 cm). Lens dynamics are driven by density contrasts of saline and fresh water, recharge rate and Kf-values of the medium. We used a time-dependent, sequential application of the tracers uranine, eosine and indigotine, to represent different recharge events. With a stepwise increase of freshwater recharge, we could show that the maximum thickness of the lens increased in a non-linear behavior. Moreover we measured that the degradation of a freshwater lens after turning off the precipitation does not follow the same function as its development does. This means that a steady state freshwater lens does not degrade as fast as it develops under constant recharge. On the other side, we could show that this is not true for a partial degradation of the lens due to passing forces, like anthropogenic pumping or climate change. This is, because the recovery to equilibrium is always a quasi asymptotic process. Thus, times of re-equilibration to steady state will take longer after e.g. a drought, than the degradation during the draught itself. This behavior could also be verified applying the numerical finite-element model FEFLOW. In addition, numerical simulations will be used to close the gap between laboratory results and future field investigations. For example, impacts due to sea level rise induced by climate change can be up-scaled and compared to the results achieved from physical experiments. Analytical models (e.g. Fetter 1972, Vacher et al. 1990, Chesnaux & Allen 2007) were used as benchmarks in our investigations. Models in general are simplifications of a real situation trying to display the relevant processes. For further investigations it is planned to compare different models and generate new benchmark experiments to improve the accuracy of existing models.
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NASA Astrophysics Data System (ADS)
Zazzo, A.; Smith, G. R.; Patterson, W. P.; Dufour, E.
2006-09-01
We evaluate the use of oxygen isotope values of biogenic apatite for tracking freshwater to marine migration in modern and fossil Pacific sockeye salmon. Oxygen isotope analyses of otoliths, vertebrae, and teeth of three anadromous modern sockeye salmon from Alaska establish a basis for the interpretation of fossil vertebrae and tooth apatite from Pleistocene sockeye salmon of the Skokomish River Valley, Washington. High resolution δ18O profiles in salmon otoliths provide, at a monthly resolution, a detailed record of individual history including continental rearing, migration to sea, seasonal variation in sea surface temperatures during marine life, and spawning migration before capture. Pacific salmon teeth are constantly renewed with the last set of teeth forming under the influence of freshwater. Therefore, they do not allow inference concerning sea-run versus landlocked life history in fossil salmon. Salmon vertebrae are also ambiguous indicators of life history regarding fresh versus marine water because centra are minimally ossified in the freshwater stages of life and the outermost layer of vertebral bone might be resorbed to provide nutrients during the non-feeding phase of the spawning migration. Therefore, δ18O values of accretionary growth rings in sea-run salmon vertebrae are dominated by the marine signal only if they are not diagenetically altered in freshwater deposits. In Pleistocene sockeye reported here, neither the teeth nor vertebral apatite present clear marine δ18O values due to the combined effects of tooth replacement and diagenetic alteration of bone and dentine. δ18O(PO 4) values of fossil vertebrae are intermediate between δ18O(PO 4) values of enamel and basal tooth dentin. Assuming a similar rate of isotope exchange of vertebrae and dentine with freshwater during diagenesis, these results are interpreted to reflect formation of the teeth under the influence of freshwater, and formation of the vertebrae under the influence of oceanic water. Our approach demonstrates that when appropriate knowledge of tissue formation is available, isotopic differences between altered and unaltered tissue holds promise of distinguishing between marine and freshwater origin of the tissues.
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NASA Astrophysics Data System (ADS)
Critto, Andrea; Torresan, Silvia; Ronco, Paolo; Zennaro, Federica; Santini, Monia; Trabucco, Antonio; Marcomini, Antonio
2016-04-01
Climate change is already affecting the frequency of drought events which may threaten the current stocks of water resources and thus the availability of freshwater for the irrigation. The achievement of a sustainable equilibrium between the availability of water resources and the irrigation demand is essentially related to the planning and implementation of evidence-based adaptation strategies and actions. In this sense, the improvement (of existing) and the development of (new) appropriate risk assessment methods and tools to evaluate the impact of drought events on irrigated crops is fundamental in order to assure that the agricultural yields are appropriate to meet the current and future food and market demand. This study evaluates the risk of hydrological drought on the irrigated agronomic compartment of Apulia, a semi-arid region in Southern Italy. We applied a stepwise Regional Risk Assessment (RRA) procedure, based on the consecutive analysis of hazards, exposure, vulnerability and risks, integrating the qualitative and quantitative available information. Future climate projections for the timeframes 2021-2050 and 2041-2070 were provided by COSMO-CLM under the radiative forcing RCP4.5 and RCP8.5. The run-off feeding the water stocks of the most important irrigation reservoirs in Apulia was then modeled with Arc-SWAT. Hence, the hazard analysis was carried out in order to estimate the degree of fulfillment of actual irrigation demand satisfied by water supply of different reservoirs in future scenarios. Vulnerability of exposed irrigated crops was evaluated depending on three factors accounting for crop yield variation vs water stress, water losses along the irrigation network, diversification of water supply. Resulting risk and vulnerability maps allowed: the identification of Reclamation Consortia at higher risk of not fulfilling their future irrigation demand (e.g. Capitanata Reclamation Consortia in RCP8.5 2041-2070 scenario); the ranking of most affected crops (e.g. fruit trees and vineyards); and finally, the characterization of vulnerability pattern of irrigation systems. Major achievements included the definition of a portfolio of science-driven adaptation strategies to reduce the risk pattern at both agronomic level (preferring crops with low vulnerability score, as olive groves) and at structural level (differentiating the water stocks and supplies and reducing losses and inefficiencies).
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Jones, Benjamin M; Arp, Christopher D; Hinkel, Kenneth M; Beck, Richard A; Schmutz, Joel A; Winston, Barry
2009-06-01
Lakes are dominant landforms in the National Petroleum Reserve Alaska (NPRA) as well as important social and ecological resources. Of recent importance is the management of these freshwater ecosystems because lakes deeper than maximum ice thickness provide an important and often sole source of liquid water for aquatic biota, villages, and industry during winter. To better understand seasonal and annual hydrodynamics in the context of lake morphometry, we analyzed lakes in two adjacent areas where winter water use is expected to increase in the near future because of industrial expansion. Landsat Thematic Mapper and Enhanced Thematic Mapper Plus imagery acquired between 1985 and 2007 were analyzed and compared with climate data to understand interannual variability. Measured changes in lake area extent varied by 0.6% and were significantly correlated to total precipitation in the preceding 12 months (p < 0.05). Using this relation, the modeled lake area extent from 1985 to 2007 showed no long-term trends. In addition, high-resolution aerial photography, bathymetric surveys, water-level monitoring, and lake-ice thickness measurements and growth models were used to better understand seasonal hydrodynamics, surface area-to-volume relations, winter water availability, and more permanent changes related to geomorphic change. Together, these results describe how lakes vary seasonally and annually in two critical areas of the NPRA and provide simple models to help better predict variation in lake-water supply. Our findings suggest that both overestimation and underestimation of actual available winter water volume may occur regularly, and this understanding may help better inform management strategies as future resource use expands in the NPRA.
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Jones, Benjamin M.; Arp, C.D.; Hinkel, Kenneth M.; Beck, R.A.; Schmutz, J.A.; Winston, B.
2009-01-01
Lakes are dominant landforms in the National Petroleum Reserve Alaska (NPRA) as well as important social and ecological resources. Of recent importance is the management of these freshwater ecosystems because lakes deeper than maximum ice thickness provide an important and often sole source of liquid water for aquatic biota, villages, and industry during winter. To better understand seasonal and annual hydrodynamics in the context of lake morphometry, we analyzed lakes in two adjacent areas where winter water use is expected to increase in the near future because of industrial expansion. Landsat Thematic Mapper and Enhanced Thematic Mapper Plus imagery acquired between 1985 and 2007 were analyzed and compared with climate data to understand interannual variability. Measured changes in lake area extent varied by 0.6% and were significantly correlated to total precipitation in the preceding 12 months (p < 0.05). Using this relation, the modeled lake area extent from 1985 to 2007 showed no long-term trends. In addition, high-resolution aerial photography, bathymetric surveys, water-level monitoring, and lake-ice thickness measurements and growth models were used to better understand seasonal hydrodynamics, surface area-to-volume relations, winter water availability, and more permanent changes related to geomorphic change. Together, these results describe how lakes vary seasonally and annually in two critical areas of the NPRA and provide simple models to help better predict variation in lake-water supply. Our findings suggest that both overestimation and underestimation of actual available winter water volume may occur regularly, and this understanding may help better inform management strategies as future resource use expands in the NPRA. ?? 2008 Springer Science+Business Media, LLC.
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Chen, Yushun; Todd, Andrew S.; Murphy, Margaret H.; Lomnicky, Gregg
2016-01-01
Healthy freshwater ecosystems are a critical component of the world's economy, with a critical role in maintaining public health, inland biological diversity, and overall quality of life. Globally, our climate is changing, with air temperature and precipitation regimes deviating significantly from historical patterns. Healthy freshwater ecosystems are a critical component of the world's economy, with a critical role in maintaining public health, inland biological diversity, and overall quality of life. Globally, our climate is changing, with air temperature and precipitation regimes deviating significantly from historical patterns. Changes anticipated with climate change in the future are likely to have a profound effect on inland aquatic ecosystems through diverse pathways, including changes in water quality. In this brief article, we present an initial discussion of several of the water quality responses that can be anticipated to occur within inland water bodies with climate change and how those changes are likely to impact fishes.
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Environmental consequences of oil production from oil sands
NASA Astrophysics Data System (ADS)
Rosa, Lorenzo; Davis, Kyle F.; Rulli, Maria C.; D'Odorico, Paolo
2017-02-01
Crude oil from oil sands will constitute a substantial share of future global oil demand. Oil sands deposits account for a third of globally proven oil reserves, underlie large natural forested areas, and have extraction methods requiring large volumes of freshwater. Yet little work has been done to quantify some of the main environmental impacts of oil sands operations. Here we examine forest loss and water use for the world's major oil sands deposits. We calculate actual and potential rates of water use and forest loss both in Canadian deposits, where oil sands extraction is already taking place, and in other major deposits worldwide. We estimated that their exploitation, given projected production trends, could result in 1.31 km3 yr-1 of freshwater demand and 8700 km2 of forest loss. The expected escalation in oil sands extraction thus portends extensive environmental impacts.
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Monitoring Everglades freshwater marsh water level using L-band synthetic aperture radar backscatter
Kim, Jin-Woo; Lu, Zhong; Jones, John W.; Shum, C.K.; Lee, Hyongki; Jia, Yuanyuan
2014-01-01
The Florida Everglades plays a significant role in controlling floods, improving water quality, supporting ecosystems, and maintaining biodiversity in south Florida. Adaptive restoration and management of the Everglades requires the best information possible regarding wetland hydrology. We developed a new and innovative approach to quantify spatial and temporal variations in wetland water levels within the Everglades, Florida. We observed high correlations between water level measured at in situ gages and L-band SAR backscatter coefficients in the freshwater marsh, though C-band SAR backscatter has no close relationship with water level. Here we illustrate the complementarity of SAR backscatter coefficient differencing and interferometry (InSAR) for improved estimation of high spatial resolution water level variations in the Everglades. This technique has a certain limitation in applying to swamp forests with dense vegetation cover, but we conclude that this new method is promising in future applications to wetland hydrology research.
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Arctic Ocean Freshwater Content and Its Decadal Memory of Sea-Level Pressure
NASA Astrophysics Data System (ADS)
Johnson, Helen L.; Cornish, Sam B.; Kostov, Yavor; Beer, Emma; Lique, Camille
2018-05-01
Arctic freshwater content (FWC) has increased significantly over the last two decades, with potential future implications for the Atlantic meridional overturning circulation downstream. We investigate the relationship between Arctic FWC and atmospheric circulation in the control run of a coupled climate model. Multiple linear lagged regression is used to extract the response of total Arctic FWC to a hypothetical step increase in the principal components of sea-level pressure. The results demonstrate that the FWC adjusts on a decadal timescale, consistent with the idea that wind-driven ocean dynamics and eddies determine the response of Arctic Ocean circulation and properties to a change in surface forcing, as suggested by idealized models and theory. Convolving the response of FWC to a change in sea-level pressure with historical sea-level pressure variations reveals that the recent observed increase in Arctic FWC is related to natural variations in sea-level pressure.
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Cylindrospermopsin: A Decade of Progress on Bioaccumulation Research
Kinnear, Susan
2010-01-01
Cylindrospermopsin (CYN) is rapidly being recognised as one of the most globally important of the freshwater algal toxins. The ever-expanding distribution of CYN producers into temperate zones is heightening concern that this toxin will represent serious human, as well as environmental, health risks across many countries. Since 1999, a number of studies have demonstrated the ability for CYN to bioaccumulate in freshwater organisms. This paper synthesizes the most current information on CYN accumulation, including notes on the global distribution of CYN producers, and a précis of CYN’s ecological and human effects. Studies on the bioaccumulation of CYN are systematically reviewed, together with an analysis of patterns of accumulation. A discussion on the factors influencing bioaccumulation rates and potential is also provided, along with notes on detection, monitoring and risk assessments. Finally, key gaps in the existing research are identified for future study. PMID:20411114
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Ballantyne, James S
2016-09-01
The urea-retaining strategy of elasmobranchs has shaped their biochemistry and physiology; from their metabolic organization to the structure of their membranes. It has also affected their capacity to live in freshwater. Although much new information has been uncovered in the past 30years, many unanswered questions remain. These include: a) why was urea selected as the major organic osmolyte, b) why is glutamine used as a nitrogen donor, c) why was plasma albumin lost in marine elasmobranchs, d) what membranes are involved in urea retention in the gills, e) how do urea and trimethylamine N-oxide (TMAO) affect membranes, and f) why retain urea in freshwater. Hypotheses are presented for future investigations but some questions may require a time machine to answer. Copyright © 2016 Elsevier Inc. All rights reserved.
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Using the Asian clam as an indicator of microplastic pollution in freshwater ecosystems.
Su, Lei; Cai, Huiwen; Kolandhasamy, Prabhu; Wu, Chenxi; Rochman, Chelsea M; Shi, Huahong
2018-03-01
Bioindicators play an important role in understanding pollution levels, bioavailability and the ecological risks of contaminants. Several bioindicators have been suggested for understanding microplastic in the marine environment. A bioindicator for microplastics in the freshwater environment does not exist. In our previous studies, we found a high frequency of microplastic pollution in the Asian clam (Corbicula fluminea) in Taihu Lake, China. In the present study, we conducted a large-scale survey of microplastic pollution in Asian clams, water and sediment from 21 sites in the Middle-Lower Yangtze River Basin from August to October of 2016. The Asian clam was available in all sites, which included diverse freshwater systems such as lakes, rivers and estuaries. Microplastics were found at concentrations ranging from 0.3-4.9 items/g (or 0.4-5.0 items/individual) in clams, 0.5-3.1 items/L in water and 15-160 items/kg in sediment. Microfibers were the most dominant types of microplastics found, accounting for 60-100% in clams across all sampling sites. The size of microplastics ranged from 0.021-4.83 mm, and microplastics in the range of 0.25-1 mm were dominant. The abundance, size distribution and color patterns of microplastics in clams more closely resembled those in sediment than in water. Because microplastic pollution in the Asian clam reflected the variability of microplastic pollution in the freshwater environments, we demonstrated the Asian clam as an bioindicator of microplastic pollution in freshwater systems, particularly for sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Development of a coastal drought index using salinity data
Conrads, Paul; Darby, Lisa S.
2017-01-01
A critical aspect of the uniqueness of coastal drought is the effects on the salinity dynamics of creeks, rivers, and estuaries. The location of the freshwater–saltwater interface along the coast is an important factor in the ecological and socioeconomic dynamics of coastal communities. Salinity is a critical response variable that integrates hydrologic and coastal dynamics including sea level, tides, winds, precipitation, streamflow, and tropical storms. The position of the interface determines the composition of freshwater and saltwater aquatic communities as well as the freshwater availability for water intakes. Many definitions of drought have been proposed, with most describing a decline in precipitation having negative impacts on the water supply. Indices have been developed incorporating data such as rainfall, streamflow, soil moisture, and groundwater levels. These water-availability drought indices were developed for upland areas and may not be ideal for characterizing coastal drought. The availability of real-time and historical salinity datasets provides an opportunity for the development of a salinity-based coastal drought index. An approach similar to the standardized precipitation index (SPI) was modified and applied to salinity data obtained from sites in South Carolina and Georgia. Using the SPI approach, the index becomes a coastal salinity index (CSI) that characterizes coastal salinity conditions with respect to drought periods of higher-saline conditions and wet periods of higher-freshwater conditions. Evaluation of the CSI indicates that it provides additional coastal response information as compared to the SPI and the Palmer hydrologic drought index, and the CSI can be used for different estuary types and for comparison of conditions along coastlines.
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Petes, Laura E; Brown, Alicia J; Knight, Carley R
2012-01-01
Increases in the frequency, duration, and severity of regional drought pose major threats to the health and integrity of downstream ecosystems. During 2007–2008, the U.S. southeast experienced one of the most severe droughts on record. Drought and water withdrawals in the upstream watershed led to decreased freshwater input to Apalachicola Bay, Florida, an estuary that is home to a diversity of commercially and ecologically important organisms. This study applied a combination of laboratory experiments and field observations to investigate the effects of reduced freshwater input on Apalachicola oysters. Oysters suffered significant disease-related mortality under high-salinity, drought conditions, particularly during the warm summer months. Mortality was size-specific, with large oysters of commercially harvestable size being more susceptible than small oysters. A potential salinity threshold was revealed between 17 and 25 ppt, where small oysters began to suffer mortality, and large oysters exhibited an increase in mortality. These findings have important implications for watershed management, because upstream freshwater releases could be carefully timed and allocated during stressful periods of the summer to reduce disease-related oyster mortality. Integrated, forward-looking water management is needed, particularly under future scenarios of climate change and human population growth, to sustain the valuable ecosystem services on which humans depend. PMID:22957175
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Stoks, Robby; Geerts, Aurora N; De Meester, Luc
2014-01-01
We integrated the evidence for evolutionary and plastic trait changes in situ in response to climate change in freshwater invertebrates (aquatic insects and zooplankton). The synthesis on the trait changes in response to the expected reductions in hydroperiod and increases in salinity indicated little evidence for adaptive, plastic, and genetic trait changes and for local adaptation. With respect to responses to temperature, there are many studies on temporal trait changes in phenology and body size in the wild that are believed to be driven by temperature increases, but there is a general lack of rigorous demonstration whether these trait changes are genetically based, adaptive, and causally driven by climate change. Current proof for genetic trait changes under climate change in freshwater invertebrates stems from a limited set of common garden experiments replicated in time. Experimental thermal evolution experiments and common garden warming experiments associated with space-for-time substitutions along latitudinal gradients indicate that besides genetic changes, also phenotypic plasticity and evolution of plasticity are likely to contribute to the observed phenotypic changes under climate change in aquatic invertebrates. Apart from plastic and genetic thermal adjustments, also genetic photoperiod adjustments are widespread and may even dominate the observed phenological shifts. PMID:24454547
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Green, Timothy W.; Slone, Daniel H.; Swain, Eric D.; Cherkiss, Michael S.; Lohmann, Melinda; Mazzotti, Frank J.; Rice, Kenneth G.
2014-01-01
The distribution and abundance of the American crocodile (Crocodylus acutus) in the Florida Everglades is dependent on the timing, amount, and location of freshwater flow. One of the goals of the Comprehensive Everglades Restoration Plan (CERP) is to restore historic freshwater flows to American crocodile habitat throughout the Everglades. To predict the impacts on the crocodile population from planned restoration activities, we created a stage-based spatially explicit crocodile population model that incorporated regional hydrology models and American crocodile research and monitoring data. Growth and survival were influenced by salinity, water depth, and density-dependent interactions. A stage-structured spatial model was used with discrete spatial convolution to direct crocodiles toward attractive sources where conditions were favorable. The model predicted that CERP would have both positive and negative impacts on American crocodile growth, survival, and distribution. Overall, crocodile populations across south Florida were predicted to decrease approximately 3 % with the implementation of CERP compared to future conditions without restoration, but local increases up to 30 % occurred in the Joe Bay area near Taylor Slough, and local decreases up to 30 % occurred in the vicinity of Buttonwood Canal due to changes in salinity and freshwater flows.
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Environmental factors that influence cyanobacteria and geosmin occurrence in reservoirs
Journey, Celeste A.; Beaulieu, Karen M.; Bradley, Paul M.; Bradley, Paul M.
2013-01-01
Phytoplankton are small to microscopic, free-floating algae that inhabit the open water of freshwater, estuarine, and saltwater systems. In freshwater lake and reservoirs systems, which are the focus of this chapter, phytoplankton communities commonly consist of assemblages of the major taxonomic groups, including green algae, diatoms, dinoflagellates, and cyanobacteria. Cyanobacteria are a diverse group of single-celled organisms that can exist in a wide range of environments, not just open water, because of their adaptability. It is the adaptability of cyanobacteria that enables this group to dominate the phytoplankton community and even form nuisance or harmful blooms under certain environmental conditions. In fact, cyanobacteria are predicted to adapt favorably to future climate change in freshwater systems compared to other phytoplankton groups because of their tolerance to rising temperatures, enhanced vertical thermal stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns. Understanding those environmental conditions that favor cyanobacterial dominance and bloom formation has been the focus of research throughout the world because of the concomitant production and release of nuisance and toxic cyanobacterial-derived compounds. However, the complex interaction among the physical, chemical, and biological processes within lakes, reservoirs, and large rivers often makes it difficult to identify primary environmental factors that cause the production and release of these cyanobacterial by-products.
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Thomas, Jonathan V.; Stanton, Gregory P.; Lambert, Rebecca B.
2012-01-01
Although analyses of daily mean equivalent freshwater heads for the East Uvalde transect indicated that the gradient across the freshwater/saline-water interface varied between into and out of the freshwater zone, the data indicate that there was a slightly longer period during which the gradient was out of the freshwater zone. Analyses of all daily mean equivalent freshwater heads for the Tri-County transect indicated that the lateral-head gradients across the freshwater/saline-water interface were typically mixed (not indicative of flow into or out of freshwater zone). Assessment of the daily mean equivalent freshwater heads indicated that, although the lateral-head gradient at the Kyle transect varied between into and out of the freshwater zone, the lateral-head gradient was typically from the transition zone into the freshwater zone.
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Blue Water Trade-Offs With Vegetation in a CO2-Enriched Climate
NASA Astrophysics Data System (ADS)
Mankin, Justin S.; Seager, Richard; Smerdon, Jason E.; Cook, Benjamin I.; Williams, A. Park; Horton, Radley M.
2018-04-01
Present and future freshwater availability and drought risks are physically tied to the responses of surface vegetation to increasing CO2. A single-model large ensemble identifies the occurrence of colocated warming- and CO2-induced leaf area index increases with summer soil moisture declines. This pattern of "greening" and "drying," which occurs over 42% of global vegetated land area, is largely attributable to changes in the partitioning of precipitation at the land surface away from runoff and toward terrestrial vegetation ecosystems. Changes in runoff and ecosystem partitioning are inversely related, with changes in runoff partitioning being governed by changes in precipitation (mean and extremes) and ecosystem partitioning being governed by ecosystem water use and surface resistance to evapotranspiration (ET). Projections show that warming-influenced and CO2-enriched terrestrial vegetation ecosystems use water that historically would have been partitioned to runoff over 48% of global vegetated land areas, largely in Western North America, the Amazon, and Europe, many of the same regions with colocated greening and drying. These results have implications for how water available for people will change in response to anthropogenic warming and raise important questions about model representations of vegetation water responses to high CO2.
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Helweg, David A.; Keener, Victoria; Burgett, Jeff M.
2016-07-14
In the subtropical and tropical Pacific islands, changing climate is predicted to influence precipitation and freshwater availability, and thus is predicted to impact ecosystems goods and services available to ecosystems and human communities. The small size of high Hawaiian Islands, plus their complex microlandscapes, require downscaling of global climate models to provide future projections of greater skill and spatial resolution. Two different climate modeling approaches (physics-based dynamical downscaling and statistics-based downscaling) have produced dissimilar projections. Because of these disparities, natural resource managers and decision makers have low confidence in using the modeling results and are therefore are unwilling to include climate-related projections in their decisions. In September 2015, the Pacific Islands Climate Science Center (PICSC), the Pacific Islands Climate Change Cooperative (PICCC), and the Pacific Regional Integrated Sciences and Assessments (Pacific RISA) program convened a 2-day facilitated workshop in which the two modeling teams, plus key model users and resource managers, were brought together for a comparison of the two approaches, culminating with a discussion of how to provide predictions that are useable by resource managers. The proceedings, discussions, and outcomes of this Workshop are summarized in this Open-File Report.
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NASA Astrophysics Data System (ADS)
Li, D.; Li, S.
2016-12-01
Freshwater service, as the most important support ecosystem service, is essential to human survival and development. Many studies have evidenced the spatial differences in the supply and demand of ecosystem services and raised the concept of ecosystem service flow. However, rather few studies quantitatively characterize the freshwater service flow. This paper aims to quantify the effect of freshwater ecosystem service flow on downstream areas in Beijing-Tianjin-Hebei (BTH) region, China over 2000, 2005 and 2010. We computed the freshwater ecosystem service provision with InVEST model. We calculated freshwater ecosystem service consumption with water quota method. We simulated the freshwater ecosystem service flow using our simplified flow model and assessed the regional water security with the improved freshwater security index. The freshwater provision service mainly depends on climatic factors that cannot be influenced by management, while the freshwater consumption service is constrained by human activities. Furthermore, the decrease of water quota for agricultural, domestic and industrial water counteracts the impact of increasing freshwater demand. The analysis of freshwater ecosystem service flow reveals that the majority area of the BTH (69.2%) is affected by upstream freshwater. If freshwater ecosystem service flow is considered, the water safety areas of the whole BTH account for 66.9%, 66.1%, 71.3%, which increase 6.4%, 6.8% and 5.7% in 2000, 2005 and 2010, respectively. These results highlight the need to understand the teleconnections between distant freshwater ecosystem service provision and local freshwater ecosystem service use. This approach therefore helps managers choose specific management and investment strategies for critical upstream freshwater provisions across different regions.
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Hybel, A-M; Godskesen, B; Rygaard, M
2015-09-01
Indicators of the impact on freshwater resources are becoming increasingly important in the evaluation of urban water systems. To reveal the importance of spatial resolution, we investigated how the choice of catchment scale influenced the freshwater impact assessment. Two different indicators were used in this study: the Withdrawal-To-Availability ratio (WTA) and the Water Stress Index (WSI). Results were calculated for three groundwater based Danish urban water supplies (Esbjerg, Aarhus, and Copenhagen). The assessment was carried out at three spatial levels: (1) the groundwater body level, (2) the river basin level, and (3) the regional level. The assessments showed that Copenhagen's water supply had the highest impact on the freshwater resource per cubic meter of water abstracted, with a WSI of 1.75 at Level 1. The WSI values were 1.64 for Aarhus's and 0.81 for Esbjerg's water supply. Spatial resolution was identified as a major factor determining the outcome of the impact assessment. For the three case studies, WTA and WSI were 27%-583% higher at Level 1 than impacts calculated for the regional scale. The results highlight that freshwater impact assessments based on regional data, rather than sub-river basin data, may dramatically underestimate the actual impact on the water resource. Furthermore, this study discusses the strengths and shortcomings of the applied indicator approaches. A sensitivity analysis demonstrates that although WSI has the highest environmental relevance, it also has the highest uncertainty, as it requires estimations of non-measurable environmental water requirements. Hence, the development of a methodology to obtain more site-specific and relevant estimations of environmental water requirements should be prioritized. Finally, the demarcation of the groundwater resource in aquifers remains a challenge for establishing a consistent method for benchmarking freshwater impacts caused by groundwater abstraction. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Davis, Jenny; O'Grady, Anthony P; Dale, Allan; Arthington, Angela H; Gell, Peter A; Driver, Patrick D; Bond, Nick; Casanova, Michelle; Finlayson, Max; Watts, Robyn J; Capon, Samantha J; Nagelkerken, Ivan; Tingley, Reid; Fry, Brian; Page, Timothy J; Specht, Alison
2015-11-15
Intensification of the use of natural resources is a world-wide trend driven by the increasing demand for water, food, fibre, minerals and energy. These demands are the result of a rising world population, increasing wealth and greater global focus on economic growth. Land use intensification, together with climate change, is also driving intensification of the global hydrological cycle. Both processes will have major socio-economic and ecological implications for global water availability. In this paper we focus on the implications of land use intensification for the conservation and management of freshwater ecosystems using Australia as an example. We consider this in the light of intensification of the hydrologic cycle due to climate change, and associated hydrological scenarios that include the occurrence of more intense hydrological events (extreme storms, larger floods and longer droughts). We highlight the importance of managing water quality, the value of providing environmental flows within a watershed framework and the critical role that innovative science and adaptive management must play in developing proactive and robust responses to intensification. We also suggest research priorities to support improved systemic governance, including adaptation planning and management to maximise freshwater biodiversity outcomes while supporting the socio-economic objectives driving land use intensification. Further research priorities include: i) determining the relative contributions of surface water and groundwater in supporting freshwater ecosystems; ii) identifying and protecting freshwater biodiversity hotspots and refugia; iii) improving our capacity to model hydro-ecological relationships and predict ecological outcomes from land use intensification and climate change; iv) developing an understanding of long term ecosystem behaviour; and v) exploring systemic approaches to enhancing governance systems, including planning and management systems affecting freshwater outcomes. A major policy challenge will be the integration of land and water management, which increasingly are being considered within different policy frameworks. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.
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Potential effects of climate change on freshwater ecosystems of the New England/Mid-Atlantic Region
Moore, M.V.; Pace, M.L.; Mather, J.R.; Murdoch, Peter S.; Howarth, R.W.; Folt, C.L.; Chen, C.-Y.; Hemond, Harold F.; Flebbe, P.A.; Driscoll, C.T.
1997-01-01
Numerous freshwater ecosystems, dense concentrations of humans along the eastern seaboard, extensive forests and a history of intensive land use distinguish the New England/Mid-Atlantic Region. Human population densities are forecast to increase in portions of the region at the same time that climate is expected to be changing. Consequently, the effects of humans and climatic change are likely to affect freshwater ecosystems within the region interactively. The general climate, at present, is humid continental, and the region receives abundant precipitation. Climatic projections for a 2 ??CO2 atmosphere, however, suggest warmer and drier conditions for much of this region. Annual temperature increases ranging from 3-5??C are projected, with the greatest increases occurring in autumn or winter. According to a water balance model, the projected increase in temperature will result in greater rates of evaporation and evapotranspiration. This could cause a 21 and 31% reduction in annual stream flow in the southern and northern sections of the region, respectively, with greatest reductions occurring in autumn and winter. The amount and duration of snow cover is also projected to decrease across the region, and summer convective thunderstorms are likely to decrease in frequency but increase in intensity. The dual effects of climate change and direct anthropogenic stress will most likely alter hydrological and biogeochemical processes, and, hence, the floral and faunal communities of the region's freshwater ecosystems. For example, the projected increase in evapotranspiration and evaporation could eliminate most bog ecosystems, and increases in water temperature may increase bioaccumulation, and possibly biomagnification, of organic and inorganic contaminants. Not all change may be adverse. For example, a decrease in runoff may reduce the intensity of ongoing estuarine eutrophication, and acidification of aquatic habitats during the spring snowmelt period may be ameliorated. Recommendations for future monitoring efforts include: (1) extending and improving data on the distribution, abundance and effect of anthropogenic Stressors (non-point pollution) within the region; and (2) improving scientific knowledge regarding the contemporary distribution and abundance of aquatic species. Research recommendations include: (1) establishing a research centre(s) where field studies designed to understand interactions between freshwater ecosystems and climate change can be conducted; (2) projecting the future distribution, activities and direct effects of humans within the region; (3) developing mathematical analyses, experimental designs and aquatic indicators that distinguish between climatic and anthropogenic effects on aquatic systems; (4) developing and refining projections of climate variability such that the magnitude, frequency and seasonal timing of extreme events can be forecast; and (5) describing quantitatively the flux of materials (sediments, nutrients, metals) from watersheds characterized by a mosaic of land uses. ?? 1997 by John Wiley & Sons, Ltd.
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Means and extremes: building variability into community-level climate change experiments.
Thompson, Ross M; Beardall, John; Beringer, Jason; Grace, Mike; Sardina, Paula
2013-06-01
Experimental studies assessing climatic effects on ecological communities have typically applied static warming treatments. Although these studies have been informative, they have usually failed to incorporate either current or predicted future, patterns of variability. Future climates are likely to include extreme events which have greater impacts on ecological systems than changes in means alone. Here, we review the studies which have used experiments to assess impacts of temperature on marine, freshwater and terrestrial communities, and classify them into a set of 'generations' based on how they incorporate variability. The majority of studies have failed to incorporate extreme events. In terrestrial ecosystems in particular, experimental treatments have reduced temperature variability, when most climate models predict increased variability. Marine studies have tended to not concentrate on changes in variability, likely in part because the thermal mass of oceans will moderate variation. In freshwaters, climate change experiments have a much shorter history than in the other ecosystems, and have tended to take a relatively simple approach. We propose a new 'generation' of climate change experiments using down-scaled climate models which incorporate predicted changes in climatic variability, and describe a process for generating data which can be applied as experimental climate change treatments. © 2013 John Wiley & Sons Ltd/CNRS.
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NASA Astrophysics Data System (ADS)
Weber, M. C.; Ward, A. S.; Muste, M.
2014-12-01
The salinization of groundwater resources is a widespread problem in arid agricultural environments. In Mewat District (Haryana, India), groundwater salinity has rendered much of the accessible supply unfit for human consumption or agriculture. Historically, this closed basin retained fresh pockets of water at the foothills of the Aravalli Hills, where monsoonal precipitation runoff from the mountains was recharged through infiltration or facilitated by man-made structures. To date, an increasing number of pumps supply the region with fresh water for consumption and agriculture leading to shrinking the freshwater zone at an accelerated pace. The potential for increased human consumption corroborated with the effects of climate change bring uncertainty about the future of water security for the Mewat communities, most of them critically bound to the existence of local water. This study addresses the sustainability of the freshwater supply under a range of land interventions and climate scenarios, using a 2-D groundwater flow and transport model. Our results quantify potential futures for this arid, groundwater-dependent location, using numerical groundwater modeling to quantify interactions between human water use, infrastructure, and climate. Outcomes of this modeling study will inform an NGO active in the area on sustainable management of groundwater resources.
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Kragh, Theis; Søndergaard, Morten; Tranvik, Lars
2008-05-01
This study reports on the interacting effect of photochemical conditioning of dissolved organic matter and inorganic phosphorus on the metabolic activity of bacteria in freshwater. Batch cultures with lake-water bacteria and dissolved organic carbon (DOC) extracted from a humic boreal river were arranged in an experimental matrix of three levels of exposure to simulated sunlight and three levels of phosphorus concentration. We measured an increase in bacterial biomass, a decrease in DOC and bacterial respiration as CO(2) production and O(2) consumption over 450 h. These measurements were used to calculate bacterial growth efficiency (BGE). Bacterial degradation of DOC increased with increasing exposure to simulated sunlight and availability of phosphorus and no detectable growth occurred on DOC that was not pre-exposed to simulated sunlight. The outcome of photochemical degradation of DOC changed with increasing availability of phosphorus, resulting in an increase in BGE from about 5% to 30%. Thus, the availability of phosphorus has major implications for the quantitative transfer of carbon in microbial food webs.
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Lee, Carol Eunmi; Moss, Wynne E; Olson, Nora; Chau, Kevin Fongching; Chang, Yu-Mei; Johnson, Kelsey E
2013-01-01
Saline to freshwater invasions have become increasingly common in recent years. A key hypothesis is that rates of freshwater invasions have been amplified in recent years by increased food concentration, yet this hypothesis has remained unexplored. We examined whether elevated food concentration could enhance freshwater tolerance, and whether this effect evolves following saline to freshwater invasions. We examined physiological response to salinity and food concentration in a 2 × 2 factorial design, using ancestral brackish and freshwater invading populations of the copepod Eurytemora affinis. We found that high food concentration significantly increases low-salinity tolerance. This effect was reduced in the freshwater population, indicating evolution following the freshwater invasion. Thus, ample food could enable freshwater invasions, allowing subsequent evolution of low-salinity tolerance even under food-poor conditions. We also compared effects of food concentration on freshwater survival between two brackish populations from the native range. Impacts of food concentration on freshwater survival differed between the brackish populations, suggesting variation in functional properties affecting their propensity to invade freshwater habitats. The key implication is that high food concentration could profoundly extend range expansions of brackishwater species into freshwater habitats, potentially allowing for condition-specific competition between saline invaders and resident freshwater species. PMID:23789033
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Evaluating Inequality or Injustice in Water Use for Food
NASA Astrophysics Data System (ADS)
D'Odorico, P.; Carr, J. A.; Seekell, D. A.
2014-12-01
Water availability and population density distributions are uneven and therefore inequality exists in human access to freshwater resources; but is this inequality unjust or only regrettable? To examine this question we formulated and evaluated elementary principles of water ethics relative to human rights for water and explored the need for global trade to improve societal access to water by transferring plant and animal commodities and the "virtual water" embedded in them. We defined human welfare benchmarks and evaluated country specific patterns of water use for food with, and without trade, over a 25-year period in order to elucidate the influence of trade and inequality on equability of water use. We found that trade improves mean water use and wellbeing, when related to human welfare benchmarks, suggesting that inequality is regrettable but not necessarily unjust. However, trade has not significantly contributed to redressing inequality. Hence, directed trade decisions can improve future conditions of water and food scarcity through reduced inequality.
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NASA Astrophysics Data System (ADS)
Miara, A.; Vorosmarty, C. J.; Stewart, R. J.; Wollheim, W. M.; Rosenzweig, B.
2012-12-01
In the Northeast US, approximately 80% of the available capacity of thermoelectric plants is dependent on the constant availability of water for cooling. Cooling is a necessary process whereby the waste thermal load of a power plant is released and the working fluid (typically steam) condensed to allow the continuation of the thermodynamic cycle and the extraction of electrical power through the action of turbines. Power plants rely on a minimum flow at a certain temperature, determined by the individual plant engineering design, to be sufficiently low for their cooling. Any change in quantity or temperature of water could reduce thermal efficiencies. As a result of the cooling process, power plants emit thermal pollution into receiving waters, which is harmful to freshwater aquatic ecosystems including its resident life forms and their biodiversity. The Clean Water Act of 1972 (CWA) was established to limit thermal pollution, particularly when rivers reach high temperatures. When river temperatures approach the threshold limit, the power plants that use freshwater for cooling are forced to reduce their thermal load and thus their output to comply with the regulations. Here we describe a model that quantifies, in a regional context, thermal pollution and estimates efficiency losses as a result of fluctuating river temperatures and flow. It does this using available data, standard engineering equations describing the heat cycle of power plants and their water use, and assumptions about the operations of the plant. In this presentation, we demonstrate the model by analyzing contrasting climates with and without the CWA, focusing on the productivity of 366 thermoelectric plants that rely on water for cooling in the Northeast between the years 2000-2010. When the CWA was imposed on all simulated power plants, the model shows that during the average winter and summer, 94% and 71% of required generation was met from the power plants, respectively. This suggests that if all power plants were to comply with the CWA and if temperatures do increase in the future as is expected under greenhouse warming, electric power generation in the Northeast may become limited, particularly in the summer. To avoid a potential energy gap, back-up generators and other electric infrastructure, such as hydropower, may have to come online in order to meet the total electric demand. Furthermore, it is clear that the methodology and steps taken in the model are required to more accurately understand, estimate and evaluate the relationship between energy production, environmental and energy policy and biodiversity under forecasted and historic climate conditions. Our ongoing work uses this model to explore various future scenarios of policy, climate and natural resource management in the Northeastern US for the period 2010-2100.
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Freshwater Megafauna: Flagships for Freshwater Biodiversity under Threat.
Carrizo, Savrina F; Jähnig, Sonja C; Bremerich, Vanessa; Freyhof, Jörg; Harrison, Ian; He, Fengzhi; Langhans, Simone D; Tockner, Klement; Zarfl, Christiane; Darwall, William
2017-10-01
Freshwater biodiversity is highly threatened and is decreasing more rapidly than its terrestrial or marine counterparts; however, freshwaters receive less attention and conservation investment than other ecosystems do. The diverse group of freshwater megafauna, including iconic species such as sturgeons, river dolphins, and turtles, could, if promoted, provide a valuable tool to raise awareness and funding for conservation. We found that freshwater megafauna inhabit every continent except Antarctica, with South America, Central Africa, and South and Southeast Asia being particularly species rich. Freshwater megafauna co-occur with up to 93% of mapped overall freshwater biodiversity. Fifty-eight percent of the 132 megafauna species included in the study are threatened, with 84% of their collective range falling outside of protected areas. Of all threatened freshwater species, 83% are found within the megafauna range, revealing the megafauna's capacity as flagship and umbrella species for fostering freshwater conservation.
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Freshwater Megafauna: Flagships for Freshwater Biodiversity under Threat
Carrizo, Savrina F.; Bremerich, Vanessa; Freyhof, Jörg; Harrison, Ian; He, Fengzhi; Langhans, Simone D.; Tockner, Klement; Zarfl, Christiane; Darwall, William
2017-01-01
Abstract Freshwater biodiversity is highly threatened and is decreasing more rapidly than its terrestrial or marine counterparts; however, freshwaters receive less attention and conservation investment than other ecosystems do. The diverse group of freshwater megafauna, including iconic species such as sturgeons, river dolphins, and turtles, could, if promoted, provide a valuable tool to raise awareness and funding for conservation. We found that freshwater megafauna inhabit every continent except Antarctica, with South America, Central Africa, and South and Southeast Asia being particularly species rich. Freshwater megafauna co-occur with up to 93% of mapped overall freshwater biodiversity. Fifty-eight percent of the 132 megafauna species included in the study are threatened, with 84% of their collective range falling outside of protected areas. Of all threatened freshwater species, 83% are found within the megafauna range, revealing the megafauna's capacity as flagship and umbrella species for fostering freshwater conservation. PMID:29599539
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Trends in freshwater microcrustaceans studies in Brazil between 1990 and 2014.
Silva, W M; Perbiche-Neves, G
2017-01-01
This study presents a review of scientiometric data about freshwater microcrustaceans (Copepoda, Ostracoda, Branchiopoda: Cladocera, Anostraca, Notostraca and Conchostraca) in Brazil from 1990-2014. This review is based on 179 papers published across four databases, using the following keywords in the search: microcrustaceans, Copepoda, Cyclopoida, Calanoida, Harpacticoida, Ergasilidae, Daphniidae, Moinidae, Cladocera, Ostracoda, Conchostraca, zooplankton, reservoir, river, ponds, reservoirs, wetlands, caves, lakes, limnology, ecology, aquatic, taxonomy, systematics, morphology and biogeography. No studies were identified that addressed freshwater microcrustaceans in four (Amapá, Roraima, Alagoas and Espírito Santo) of the 27 Brazilian Federative States. Forty-five percent of the included studies were concentrated within three of the most populous states (São Paulo, Minas Gerais and Paraná), which also have a long tradition of limnological study. The included studies mostly addressed reservoirs for hydropower generation (22%), multiple environments (22%), rivers (14%) and small artificial reservoirs (11%). Pools, ponds, small lakes, wetlands and phytothelma were not widely studied. Cladocera (48%) and Copepoda (48%) were the most studied groups. No studies were identified that addressed Notostraca, Anostraca or Conchostraca. The sharp increase in the number of published freshwater studies after 2000 is likely a result of increased internet facilities and the implementation of the Scielo platform. Ecology was most frequently the study focus (~50%), followed by taxonomy. Three journals (two Brazilian and one international) accounted for the publication of 44% of the Brazilian studies on microcrustaceans. We expect the frequency of studies employing newer technologies to increase in the coming years. Based on our findings, we propose that future studies should focus on the least well-studied states and should integrate biogeography and systematic approaches. Further data on the fauna within environmental sub-types in Brazil is required.
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Temperature-altered predator-prey dynamics in freshwater ponds in Arctic Greenland
NASA Astrophysics Data System (ADS)
Culler, L. E.; Ayres, M.
2011-12-01
Temperature sets the pace of many biological processes including species interactions. Describing the response of terrestrial and aquatic habitats to climate warming therefore requires studies of cross-trophic level dynamics. I use freshwater pond ecosystems in Arctic Greenland to study how the thermal environment shapes interactions between predators and their prey. This system is of interest because warming trends are notable, freshwaters are responding rapidly and dynamically to changes in temperature, and the biology of freshwaters is intimately linked to the terrestrial environment. My focal species are the Arctic mosquito (Diptera: Culicidae, Aedes nigripes) and its invertebrate predator, a predaceous diving beetle (Coleoptera: Dytiscidae, Colymbetes dolabratus). Both species develop as larvae in snow-melt ponds in May and June. I used experimental and observational studies to test effects of temperature on larval mosquito growth rates and predation rates by C. dolabratus. Results indicate strong effects of temperature on growth rate and development time but weak effects of temperature on consumption of mosquitoes by their predators. Incorporation of measured temperature response functions into a mosquito demographic model will elucidate how mosquito population dynamics in Arctic Greenland may change with temperature. For example, warming increases growth rate and decreases development time of mosquito larvae, which shortens the time larvae are exposed to predation. Additionally, decreased development time leads to an earlier mosquito emergence, with potential consequences for the health of wildlife. Evaluation of this model will reveal the importance of considering cross-trophic level dynamics when predicting mosquito population response to warming. Future studies will address interesting properties emerging from modeling, such as how shorter development time affects adult size and fitness, and connecting results to terrestrial systems in Arctic Greenland.
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Large Scale Relationship between Aquatic Insect Traits and Climate.
Bhowmik, Avit Kumar; Schäfer, Ralf B
2015-01-01
Climate is the predominant environmental driver of freshwater assemblage pattern on large spatial scales, and traits of freshwater organisms have shown considerable potential to identify impacts of climate change. Although several studies suggest traits that may indicate vulnerability to climate change, the empirical relationship between freshwater assemblage trait composition and climate has been rarely examined on large scales. We compared the responses of the assumed climate-associated traits from six grouping features to 35 bioclimatic indices (~18 km resolution) for five insect orders (Diptera, Ephemeroptera, Odonata, Plecoptera and Trichoptera), evaluated their potential for changing distribution pattern under future climate change and identified the most influential bioclimatic indices. The data comprised 782 species and 395 genera sampled in 4,752 stream sites during 2006 and 2007 in Germany (~357,000 km² spatial extent). We quantified the variability and spatial autocorrelation in the traits and orders that are associated with the combined and individual bioclimatic indices. Traits of temperature preference grouping feature that are the products of several other underlying climate-associated traits, and the insect order Ephemeroptera exhibited the strongest response to the bioclimatic indices as well as the highest potential for changing distribution pattern. Regarding individual traits, insects in general and ephemeropterans preferring very cold temperature showed the highest response, and the insects preferring cold and trichopterans preferring moderate temperature showed the highest potential for changing distribution. We showed that the seasonal radiation and moisture are the most influential bioclimatic aspects, and thus changes in these aspects may affect the most responsive traits and orders and drive a change in their spatial distribution pattern. Our findings support the development of trait-based metrics to predict and detect climate-related changes of freshwater assemblages.
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Water resources of the White Earth Indian Reservation, northwestern Minnesota
Ruhl, J.F.
1989-01-01
Surface water also is a calcium magnesium bicarbonate type. Lake waters are hard and alkaline and are mesotrophic to eutrophic in productivity. Quality of the lake and stream water is suitable for native forms of freshwater biota, although the concentration of total recoverable mercury exceeds the 0.012 micrograms per liter maximum contaminant level; that level, established by USEPA for the organic form of dissolved mercury, is intended to protect against chronic effects on freshwater life. Available information, however, indicates that the amount of mercury in edible tissue from fish in alkaline lakes of northwestern Minnesota is within safe limits. The concentrations of phosphorus and nitrate in the streams are below levels that indicate pollution problems.
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Water Reserves Program. An adaptation strategy to prevent imbalance of water in nature
NASA Astrophysics Data System (ADS)
Salinas-Rodriguez, S. A.; López Pérez, M.; Barrios Ordóñez, J.; Wickel, B.; Villón Bracamonte, R. A.
2013-12-01
Freshwater ecosystems occupy approximately 1% of the earth's surface yet possess about 12% of all known animal species. By virtue of their position in the landscape they connect terrestrial and coastal marine biomes and provide and sustain ecosystem services vital to the health and persistence of human communities. These services include the supply of water for food production, urban and industrial consumption, among others. Over the past century many freshwater ecosystems around the world have been heavily modified or lost due to the alteration of flow regimes (e.g. damming, canalization, diversion, over-abstraction). The synergistic impacts of land use change, changes in flows, chemical deterioration, and climate change have left many systems and their species very little room to adjust to change, while future projections indicate a steady increase imbalance in water demand for food and energy production and water supply to suit the needs of a growing world population. In Mexico, the focus has been to secure water for human development and maximize economic growth, which has resulted in allocation of water beyond available amounts, and that in many river basins has led imbalance of water in nature. As a consequence episodic water scarcity severely constrains freshwater ecosystems and the services they provide. Climatic change and variability are presenting serious challenges to a country that already is experiencing serious strain on its water resources. However, freshwater ecosystems are recognized by law as legitimate user of water, and mandate a flow allocation for the environment ('water reserve' or 'environmental flows'). Based on this legal provision the Mexican government through the National Water Commission (Conagua), with support of the Alliance WWF - Fundación Gonzalo Río Arronte, and the Interamerican Development Bank, has launched a national program to identify and implement 'water reserves': basins where environmental flows will be secured and allocated, and where the flow regime is then protected before over-allocation takes place. The strategy has been to identify and protect basins with an availability of water that is close to their natural flow regime and that also have a high conservation value (based on prior national conservation priority definitions such as protected areas, and biodiversity conservation gap analyses) in order to implement legal restrictions on water resource development. With such protection, these systems will be best positioned to adjust and respond to water shortages, and regime shifts. To date, 189 basins around the country were identified as potential water reserves. The next step will be the nomination of these water reserves to be integrated in the National Water Reserves Program. This program forms the core of the official Mexican government adaptation strategy towards climate prepared water management, which recognizes that water reserves are the buffer society needs to face uncertainty, imbalance of the man-made, global changes, and thus to reduce water scarcity risk. The development of activities that alter the natural flow regime such as dams and levees are closely examined, and would potentially be restricted.
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NASA Astrophysics Data System (ADS)
Lehnen, Sarah E.; Krementz, David G.
2013-08-01
Populations of many shorebird species are declining; habitat loss and degradation are among the leading causes for these declines. Shorebirds use a variety of habitats along interior migratory routes including managed moist soil units, natural wetlands, sandbars, and agricultural lands such as harvested rice fields. Less well known is shorebird use of freshwater aquaculture facilities, such as commercial cat- and crayfish ponds. We compared shorebird habitat use at drained aquaculture ponds, moist soil units, agricultural areas, sandbars and other natural habitat, and a sewage treatment facility in the in the lower Mississippi River Alluvial Valley (LMAV) during autumn 2009. Six species: Least Sandpiper ( Calidris minutilla), Killdeer ( Charadrius vociferous), Semipalmated Sandpiper ( Calidris pusilla), Pectoral Sandpiper ( C. melanotos), Black-necked Stilt ( Himantopus himantopus), and Lesser Yellowlegs ( Tringa flavipes), accounted for 92 % of the 31,165 individuals observed. Sewage settling lagoons (83.4, 95 % confidence interval [CI] 25.3-141.5 birds/ha), drained aquaculture ponds (33.5, 95 % CI 22.4-44.6 birds/ha), and managed moist soil units on public lands (15.7, CI 11.2-20.3 birds/ha) had the highest estimated densities of shorebirds. The estimated 1,100 ha of drained aquaculture ponds available during autumn 2009 provided over half of the estimated requirement of 2,000 ha by the LMAV Joint Venture working group. However, because of the decline in the aquaculture industry, autumn shorebird habitats in the LMAV may be limited in the near future. Recognition of the current aquaculture habitat trends will be important to the future management activities of federal and state agencies. Should these aquaculture habitat trends continue, there may be a need for wildlife biologists to investigate other habitats that can be managed to offset the current and expected loss of aquaculture acreages. This study illustrates the potential for freshwater aquaculture to provide habitat for a taxa at risk. With the rapid growth of aquaculture worldwide, the practices of this industry deserve attention to identify benefits as well as risks to wildlife.
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Pedersen, Ulrik B; Stendel, Martin; Midzi, Nicholas; Mduluza, Takafira; Soko, White; Stensgaard, Anna-Sofie; Vennervald, Birgitte J; Mukaratirwa, Samson; Kristensen, Thomas K
2014-12-12
Freshwater snails are intermediate hosts for a number of trematodes of which some are of medical and veterinary importance. The trematodes rely on specific species of snails to complete their life cycle; hence the ecology of the snails is a key element in transmission of the parasites. More than 200 million people are infected with schistosomes of which 95% live in sub-Saharan Africa and many more are living in areas where transmission is on-going. Human infection with the Fasciola parasite, usually considered more of veterinary concern, has recently been recognised as a human health problem. Many countries have implemented health programmes to reduce morbidity and prevalence of schistosomiasis, and control programmes to mitigate food-borne fascioliasis. As these programmes are resource demanding, baseline information on disease prevalence and distribution becomes of great importance. Such information can be made available and put into practice through maps depicting spatial distribution of the intermediate snail hosts. A biology driven model for the freshwater snails Bulinus globosus, Biomphalaria pfeifferi and Lymnaea natalensis was used to make predictions of snail habitat suitability by including potential underlying environmental and climatic drivers. The snail observation data originated from a nationwide survey in Zimbabwe and the prediction model was parameterised with a high resolution Regional Climate Model. Georeferenced prevalence data on urinary and intestinal schistosomiasis and fascioliasis was used to calibrate the snail habitat suitability predictions to produce binary maps of snail presence and absence. Predicted snail habitat suitability across Zimbabwe, as well as the spatial distribution of snails, is reported for three time slices representative for present (1980-1999) and future climate (2046-2065 and 2080-2099). It is shown from the current study that snail habitat suitability is highly variable in Zimbabwe, with distinct high- and low- suitability areas and that temperature may be the main driving factor. It is concluded that future climate change in Zimbabwe may cause a reduced spatial distribution of suitable habitat of host snails with a probable exception of Bi. pfeifferi, the intermediate host for intestinal schistosomiasis that may increase around 2055 before declining towards 2100.
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McDonald, Robert I; Olden, Julian D; Opperman, Jeffrey J; Miller, William M; Fargione, Joseph; Revenga, Carmen; Higgins, Jonathan V; Powell, Jimmie
2012-01-01
Rising energy consumption in coming decades, combined with a changing energy mix, have the potential to increase the impact of energy sector water use on freshwater biodiversity. We forecast changes in future water use based on various energy scenarios and examine implications for freshwater ecosystems. Annual water withdrawn/manipulated would increase by 18-24%, going from 1,993,000-2,628,000 Mm(3) in 2010 to 2,359,000-3,271,000 Mm(3) in 2035 under the Reference Case of the Energy Information Administration (EIA). Water consumption would more rapidly increase by 26% due to increased biofuel production, going from 16,700-46,400 Mm(3) consumption in 2010 to 21,000-58,400 Mm(3) consumption in 2035. Regionally, water use in the Southwest and Southeast may increase, with anticipated decreases in water use in some areas of the Midwest and Northeast. Policies that promote energy efficiency or conservation in the electric sector would reduce water withdrawn/manipulated by 27-36 m(3)GJ(-1) (0.1-0.5 m(3)GJ(-1) consumption), while such policies in the liquid fuel sector would reduce withdrawal/manipulation by 0.4-0.7 m(3)GJ(-1) (0.2-0.3 m(3)GJ(-1) consumption). The greatest energy sector withdrawal/manipulation are for hydropower and thermoelectric cooling, although potential new EPA rules that would require recirculating cooling for thermoelectric plants would reduce withdrawal/manipulation by 441,000 Mm(3) (20,300 Mm(3) consumption). The greatest consumptive energy sector use is evaporation from hydroelectric reservoirs, followed by irrigation water for biofuel feedstocks and water used for electricity generation from coal. Historical water use by the energy sector is related to patterns of fish species endangerment, where water resource regions with a greater fraction of available surface water withdrawn by hydropower or consumed by the energy sector correlated with higher probabilities of imperilment. Since future increases in energy-sector surface water use will occur in areas of high fish endemism (e.g., Southeast), additional management and policy actions will be needed to minimize further species imperilment.
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Kocman, David; Wilson, Simon J; Amos, Helen M; Telmer, Kevin H; Steenhuisen, Frits; Sunderland, Elsie M; Mason, Robert P; Outridge, Peter; Horvat, Milena
2017-02-01
Aquatic ecosystems are an essential component of the biogeochemical cycle of mercury (Hg), as inorganic Hg can be converted to toxic methylmercury (MeHg) in these environments and reemissions of elemental Hg rival anthropogenic Hg releases on a global scale. Quantification of effluent Hg releases to aquatic systems globally has focused on discharges to the global oceans, rather than contributions to freshwater systems that affect local exposures and risks associated with MeHg. Here we produce a first-estimate of sector-specific, spatially resolved global aquatic Hg discharges to freshwater systems. We compare our release estimates to atmospheric sources that have been quantified elsewhere. By analyzing available quantitative and qualitative information, we estimate that present-day global Hg releases to freshwater environments (rivers and lakes) associated with anthropogenic activities have a lower bound of ~1000 Mg· a-1. Artisanal and small-scale gold mining (ASGM) represents the single largest source, followed by disposal of mercury-containing products and domestic waste water, metal production, and releases from industrial installations such as chlor-alkali plants and oil refineries. In addition to these direct anthropogenic inputs, diffuse inputs from land management activities and remobilization of Hg previously accumulated in terrestrial ecosystems are likely comparable in magnitude. Aquatic discharges of Hg are greatly understudied and further constraining associated data gaps is crucial for reducing the uncertainties in the global biogeochemical Hg budget.
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Kocman, David; Wilson, Simon J.; Amos, Helen M.; Telmer, Kevin H.; Steenhuisen, Frits; Sunderland, Elsie M.; Mason, Robert P.; Outridge, Peter; Horvat, Milena
2017-01-01
Aquatic ecosystems are an essential component of the biogeochemical cycle of mercury (Hg), as inorganic Hg can be converted to toxic methylmercury (MeHg) in these environments and reemissions of elemental Hg rival anthropogenic Hg releases on a global scale. Quantification of effluent Hg releases to aquatic systems globally has focused on discharges to the global oceans, rather than contributions to freshwater systems that affect local exposures and risks associated with MeHg. Here we produce a first-estimate of sector-specific, spatially resolved global aquatic Hg discharges to freshwater systems. We compare our release estimates to atmospheric sources that have been quantified elsewhere. By analyzing available quantitative and qualitative information, we estimate that present-day global Hg releases to freshwater environments (rivers and lakes) associated with anthropogenic activities have a lower bound of ~1000 Mg·a−1. Artisanal and small-scale gold mining (ASGM) represents the single largest source, followed by disposal of mercury-containing products and domestic waste water, metal production, and releases from industrial installations such as chlor-alkali plants and oil refineries. In addition to these direct anthropogenic inputs, diffuse inputs from land management activities and remobilization of Hg previously accumulated in terrestrial ecosystems are likely comparable in magnitude. Aquatic discharges of Hg are greatly understudied and further constraining associated data gaps is crucial for reducing the uncertainties in the global biogeochemical Hg budget. PMID:28157152
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Evaluation of ground-water quality data from Kentucky
Sprinkle, C.L.; Davis, R.W.; Mull, D.S.
1983-01-01
The report reviews and summarizes 10,578 chemical analyses, from 2,362 wells and springs in Kentucky. These water-quality data were collected prior to September 30, 1981, and are available in computer files of the U.S. Geological Survey. The principal water-bearing rocks in Kentucky were combined into 10 major groups to aid in data summary preparation and general description of the ground-water quality of the State. Ground water in Kentucky is generally fresh near the outcrop of the rocks comprising the aquifer. Slightly saline to briny water occurs at variable depths beneath the freshwater. Preparation of quadrilinear diagrams revealed three principal geochemical processes in the aquifers of Kentucky: (1) mixing of freshwater and saline water in an interface zone; (2) dedolomitization of the Devonian and Silurian and Lower Mississippian carbonate rocks; (3) sodium for calcium exchange in the freshwater sections of many of the sandstone-shale aquifers. A number of errors and deficiencies were found in the data base. The principal deficiencies were: (1) very few complete analyses which included important field measurements; (2) inadequate definition of the chemistry of the freshwater-saline water interface zone throughout much of the State; (3) no analyses of stable isotopes and dissolved gases; (4) fewer than 10 analyses of most trace metals, radionuclides, and man-made organic chemicals; and (5) no data on bacteria in ground water from any aquifer in the State. (USGS)
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Liu, W.-C.; Chen, W.-B.; Cheng, R.T.; Hsu, M.-H.; Kuo, A.Y.
2007-01-01
A 3-D, time-dependent, baroclinic, hydrodynamic and salinity model was implemented and applied to the Danshuei River estuarine system and the adjacent coastal sea in Taiwan. The model forcing functions consist of tidal elevations along the open boundaries and freshwater inflows from the main stream and major tributaries in the Danshuei River estuarine system. The bottom friction coefficient was adjusted to achieve model calibration and verification in model simulations of barotropic and baroclinic flows. The turbulent diffusivities were ascertained through comparison of simulated salinity time series with observations. The model simulation results are in qualitative agreement with the available field data. The validated model was then used to investigate the influence of freshwater discharge on residual current and salinity intrusion under different freshwater inflow condition in the Danshuei River estuarine system. The model results reveal that the characteristic two-layered estuarine circulation prevails most of the time at Kuan-Du station near the river mouth. Comparing the estuarine circulation under low- and mean flow conditions, the circulation strengthens during low-flow period and its strength decreases at moderate river discharge. The river discharge is a dominating factor affecting the salinity intrusion in the estuarine system. A correlation between the distance of salt intrusion and freshwater discharge has been established allowing prediction of salt intrusion for different inflow conditions. ?? 2007 Elsevier Ltd. All rights reserved.
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IDENTIFICATION AND PREDICTION OF FISH ASSEMBLAGES IN STREAMS OF THE MID-ATLANTIC HIGHLANDS, USA
Managing aquatic resources requires meaningful assessment endpoints on which to base decisions. In freshwater streams, assessment endpoints are often defined as fish communities. Given limited resources available for environmental monitoring, having a means of predicting fish a...
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WATER RESOURCE IMPLICATIONS FROM TOURISM DEVELOPMENT ALONG THE WESTERN COAST OF NICARAGUA
This project contributes to debates over the socio-environmental influences of tourism development on local populations in Central America. In the case of Nicaragua, the potential for conflict over freshwater availability appertains to tourism development and predicted dec...
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Fan, Lan-Feng; Tang, Sen-Lin; Chen, Chang-Po; Hsieh, Hwey-Lian
2012-01-01
Sulfate- and sulfite-reducing prokaryotes (SSRP) communities play a key role in both sulfur and carbon cycles. In estuarine ecosystems, sulfate concentrations change with tides and could be limited in tidal freshwater reach or deep sediments. In a subtropical estuary of northern Taiwan in December 2007, we examined the compositional changes of SSRP communities. We examined three sites: from the lower estuarine brackish-water reach (site GR and mangrove vegetation site, GM) to the upper estuarine tidal freshwater reach (site HR), as well as from surface to a 50-cm depth. The partial sequence of sulfite reductase (dsrB) genes was used as a molecular marker of SSRP, linked to polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE) techniques. SSRP communities of the DGGE profiles varied with sites according to one-way analyses of similarities (Global R = 0.69, P = 0.001). Using cluster analysis, the DGGE profile was found to show site-specific clusters and a distinct depth zonation (five, six, and two SSRP communities at the GM, GR, and HR sites, respectively). SSRP composition was highly correlated to the combination of salinity, reduced sulfur, and total organic carbon contents (BIO-ENV analysis, r ( s ) = 0.56). After analyzing a total of 35 dsrB sequences in the DGGE gel, six groups with 15 phylotypes were found, which were closely related to marine-freshwater gradient. Moreover, sequences neighboring sulfite-reducing prokaryotes were observed, in addition to those affiliated to sulfate-reducing prokaryotes. Four phylotypes harvested in HR resembled the genus Desulfitobacterium, a sulfite-reducing prokaryote, which failed to use sulfate as an electron acceptor and were active in freshwater and sulfate-limited habitat. The other five phylotypes in the HR reach belonged to the sulfate-reducing prokaryotes of the genera Desulfatiferula, Desulfosarcina, Desulfovibrio, and Desulfotomaculum, which appeared to tolerate low salinity and low sulfate supply. SSRP phylotypes at the mangrove-vegetated GM site (five phylotypes in two groups) were phylogenetically less diverse, when compared with those at the non-mangrove-vegetated GR site (three phylotypes in three groups) and the tidally influenced freshwater HR site (nine phylotypes in five groups). Phylotypes found at GR and GM were all affiliated to marine sulfate-reducing prokaryote strains of the genera Desulfofaba, Desulfobotulus, Desulfatiferula, Desulfosarcina, and Desulfotomaculum. Notably, a phylotype recorded in the surface sediment at GR resembled the genus Desulfobulbus, which was recorded from freshwater environment consisting of the freshwater input at GR during ebb tides.
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NASA Astrophysics Data System (ADS)
Rudels, Bert
2010-05-01
The freshwater added to the Arctic Ocean is stored as sea ice and as liquid freshwater residing primarily in the upper layers. This allows for simple zero order estimates of the liquid freshwater content and export based on rotationally controlled baroclinic flow. At present the freshwater outflow occurs on both sides of Greenland. In Fram Strait the sea ice export in the East Greenland Current is significantly larger than the liquid freshwater outflow, while the liquid freshwater export dominates in the Canadian Arctic Archipelago. Although the outflow in the upper layer and the freshwater export respond to short periodic wind events and longer periodic atmospheric circulation patterns, the long-term trend is controlled by the net freshwater supply - the freshwater input minus the ice export. As the ice formation and ice export are expected to diminish in a warmer climate the Canadian Arctic Archipelago, comprising several passages, should gradually carry more of the total Arctic Ocean freshwater outflow. However, the channels in the Canadian Arctic Archipelago discharge into the restricted Baffin, which also receives a part of the Fram Strait freshwater export via the West Greenland Current. In a situation with increased glacial melting and freshwater discharge from Greenland the density of the upper layer in Baffin Bay may decrease considerably. This would reduce the sea level difference between the Arctic Ocean and Baffin Bay and thus weaken the outflow through the Canadian Arctic Archipelago, in extreme cases perhaps even reverse the flow. This would shift the main Arctic Ocean liquid freshwater export from The Canadian Arctic Archipelago to Fram Strait. The zero order dynamics of the exchanges through the Canadian Arctic Archipelago and Baffin Bay are described and the possibility for a weakening of the outflow is examined.
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Artemov, Artem V; Mugue, Nikolai S; Rastorguev, Sergey M; Zhenilo, Svetlana; Mazur, Alexander M; Tsygankova, Svetlana V; Boulygina, Eugenia S; Kaplun, Daria; Nedoluzhko, Artem V; Medvedeva, Yulia A; Prokhortchouk, Egor B
2017-09-01
The three-spined stickleback (Gasterosteus aculeatus) represents a convenient model to study microevolution-adaptation to a freshwater environment. Although genetic adaptations to freshwater environments are well-studied, epigenetic adaptations have attracted little attention. In this work, we investigated the role of DNA methylation in the adaptation of the marine stickleback population to freshwater conditions. DNA methylation profiling was performed in marine and freshwater populations of sticklebacks, as well as in marine sticklebacks placed into a freshwater environment and freshwater sticklebacks placed into seawater. We showed that the DNA methylation profile after placing a marine stickleback into fresh water partially converged to that of a freshwater stickleback. For six genes including ATP4A ion pump and NELL1, believed to be involved in skeletal ossification, we demonstrated similar changes in DNA methylation in both evolutionary and short-term adaptation. This suggested that an immediate epigenetic response to freshwater conditions can be maintained in freshwater population. Interestingly, we observed enhanced epigenetic plasticity in freshwater sticklebacks that may serve as a compensatory regulatory mechanism for the lack of genetic variation in the freshwater population. For the first time, we demonstrated that genes encoding ion channels KCND3, CACNA1FB, and ATP4A were differentially methylated between the marine and the freshwater populations. Other genes encoding ion channels were previously reported to be under selection in freshwater populations. Nevertheless, the genes that harbor genetic and epigenetic changes were not the same, suggesting that epigenetic adaptation is a complementary mechanism to selection of genetic variants favorable for freshwater environment. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Water use patterns of estuarine vegetation in a tidal creek system.
Wei, Lili; Lockington, David A; Poh, Seng-Chee; Gasparon, Massimo; Lovelock, Catherine E
2013-06-01
Water availability is a key determinant of the zonation patterns in estuarine vegetation, but water availability and the use of different water sources over space and time are not well understood. We have determined the seasonal water use patterns of riparian vegetation over an estuarine ecotone. Our aim was to investigate how the water use patterns of estuarine vegetation respond to variations in the availability of tidal creek water and rain-derived freshwater. The levels of natural stable isotopes of oxygen and hydrogen were assessed in the stem of the mangrove Avicennia marina (tall and scrub growth forms), Casuarina glauca and Melaleuca quinquenervia that were distributed along transects from river/creek-front towards inland habitats. The isotopic composition of plant tissues and the potential water sources were assessed in both the wet season, when freshwater from rainfall is present, and the dry season, when mangrove trees are expected to be more dependent on tidal water, and when Casuarina and Melaleuca are expected to be dependent on groundwater. Our results indicate that rainwater during the wet season contributes significantly to estuarine vegetation, even to creek-side mangroves which are inundated by tidal creek water daily, and that estuarine vegetation depends primarily on freshwater throughout the year. In contrast, high intertidal scrub mangroves were found to use the greatest proportion of tidal creek water, supplemented by groundwater in the dry season. Contrary to prediction, inland trees C. glauca and M. quinquenervia were found also to rely predominantly on rainwater--even in the dry season. The results of this study reveal a high level of complexity in vegetation water use in estuarine settings.
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Impact of river discharge on the California coastal ocean circulation and variability
NASA Astrophysics Data System (ADS)
Leiva, J.; Chao, Y.; Farrara, J. D.; Zhang, H.
2016-12-01
A real-time California coastal ocean nowcast and forecast system is used to quantify the impact of river discharge on the California coastal ocean circulation and variability. River discharge and freshwater runoff is monitored by an extensive network of stream gages maintained through the U.S. Geological Survey, that offers archived stream flow records as well as real-time datasets. Of all the rivers monitored by the USGS, 25 empty into the Pacific Ocean and contribute a potential source of runoff data. Monthly averages for the current water year yield discharge estimates as high as 6,000 cubic meters per second of additional freshwater input into our present model. Using Regional Ocean Modeling System (ROMS), we performed simulations from October 2015 to May 2016 with and without the river discharge. Results of these model simulations are compared with available observations including both in situ and satellite. Particular attention is paid to the salinity simulation. Validation is done with comparisons to sea glider data available through Oregon State University and UC San Diego, which provides depth profiles along the California coast during this time period. Additional validation is performed through comparisons with sea surface salinity measurements from the Soil Moisture and Ocean Salinity (SMOS) mission. Continued testing for previous years, e.g. between 2011 and 2015, is being made using the Aquarius sea surface salinity data. Discharge data collected by the USGS stream gages provides a necessary source of freshwater input that must be accounted for. Incorporating a new runoff source produces a more robust model that generates improved forecasts. Following validation with available sea glider and satellite data, the enhanced model can be adapted to real-time forecasting.
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Francy, Donna S.; Graham, Jennifer L.; Stelzer, Erin A.; Ecker, Christopher D.; Brady, Amie M. G.; Pam Struffolino,; Loftin, Keith A.
2015-11-06
The results of this study showed that water-quality and environmental variables are promising for use in site-specific daily or long-term predictive models. In order to develop more accurate models to predict toxin concentrations at freshwater lake sites, data need to be collected more frequently and for consecutive days in future studies.
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Application of remote sensing to state and regional problems
NASA Technical Reports Server (NTRS)
Miller, W. F.; Clark, J. R.; Solomon, J. L.; Duffy, B.; Minchew, K.; Wright, L. H. (Principal Investigator)
1981-01-01
The objectives, accomplishments, and future plans of several LANDSAT applications projects in Mississippi are discussed. The applications include land use planning in Lowandes County, strip mine inventory and reclamation, white tailed deer habitat evaluation, data analysis support systems, discrimination of forest habitats in potential lignite areas, changes in gravel operations, and determination of freshwater wetlands for inventory and monitoring. In addition, a conceptual design for a LANDSAT based information system is discussed.
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NASA Astrophysics Data System (ADS)
Lane, J. W.; Briggs, M.; Kulongoski, J. T.; Pollock, A. L.
2013-12-01
The Palmyra Atoll National Wildlife Refuge is located in the central Pacific Ocean, about 1,000 miles south of the island of Oahu. Impacts on the atoll's hydrologic and ecologic systems are anticipated from two key anthropogenic drivers of change: (1) eradication of invasive coconut palms and replanting of native Pisonia grandis trees, and (2) global climate change. In the near-term, the palm eradication program is expected to modify the distribution and quality of groundwater proximal to the reforested areas. Longer term, sea level rise, changes in precipitation, and changes in storm frequency and intensity are expected to have a broader impact on the freshwater resources of the atoll. We have initiated a project to characterize current climatic and hydrologic conditions on Palmyra, and monitor changes in order to model baseline conditions and future changes in groundwater distribution. Because rain water harvest satisfies human need on Palmyra, the atoll enables study of groundwater resource change uncomplicated by groundwater pumping stress. Field trips conducted in 2008 and 2013 have included geophysical surveys, weather station upgrades, installation of monitoring wells, and geochemical sampling. Nine wells have been installed on Cooper Island (the largest island of the atoll), each instrumented with a combination of temperature, conductivity, and pressure sensors. Repeated frequency-domain electromagnetic conductivity surveys indicate a reduction in the thickness of the freshwater lens on the southern side of the Cooper Island since 2008, possibly linked to recent modification to the atoll's runway and drainage system. These results indicate that we can successfully capture future transformations induced by land cover and climate changes. The Palmyra Atoll project provides open-source information and insight about human-driven change to the vulnerable freshwater resources of low-lying islands; we hope others will take interest in, and make use of the hydrologic data now being collected on the atoll.
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Estuarine biodiversity as an indicator of groundwater discharge
NASA Astrophysics Data System (ADS)
Silva, A. C. F.; Tavares, P.; Shapouri, M.; Stigter, T. Y.; Monteiro, J. P.; Machado, M.; Cancela da Fonseca, L.; Ribeiro, L.
2012-01-01
Communities located in the interface between marine/brackish and freshwater habitats are likely to be early responders to climatic changes as they are exposed to both saline and freshwater conditions, and thus are expected to be sensitive to any change in their environmental conditions. Climatic effects are predicted to reduce the availability of groundwater, altering the hydrological balance on estuarine-aquifer interfaces. Here, we aimed to characterise the estuarine faunal community along a gradient dependent on groundwater input, under a predicted climatic scenario of reduction in groundwater discharge into the estuary. Sediment macrofauna was sampled along a salinity gradient following both the wet and dry seasons in 2009. Results indicated that species abundance varied significantly with the salinity gradient created by the groundwater discharge into the estuarine habitat and with sampling time. The isopode Cyathura carinata (Krøyer, 1847) and the polychaetes Heteromastus filiformis (Claparède, 1864) and Hediste diversicolor O.F. Muller, 1776 were associated with the more saline locations, while oligochaeta and Spionidae were more abundant in areas of lower salinity. The polychaete Alkmaria romijni Horst, 1919 was the dominant species and ubiquitous throughout sampling stations. This study provides evidence for estuarine fauna to be considered as a potentially valuable indicator of variation in the input of groundwater into marine-freshwater interface habitats, expected from climatic pressures on aquifer levels, condition and recharge rates. For instance, a reduction in the abundance of some polychaete species, found here to be more abundant in freshwater conditions, and increasing Oligochaeta found here on higher salinities, can potentially be early warnings of a reduction in the input of groundwater into estuaries. Estuarine benthic species are often the main prey for commercially important fish predators such as in our case study, making it important to monitor the aquatic habitat interfaces taking into consideration the estuarine macrobenthos and groundwater availability in the system.
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NASA Astrophysics Data System (ADS)
Neubauer, S. C.; Franklin, R. B.; Berrier, D. J.
2013-07-01
Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced roughly 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellular enzyme activity associated with organic matter breakdown, and determined potential rates of anaerobic carbon dioxide (CO2) and methane (CH4) production. Soils from the field plots treated with brackish water had lower carbon content and higher C : N ratios than soils from freshwater plots, indicating that saltwater intrusion reduced carbon availability and increased organic matter recalcitrance. This was reflected in reduced activities of enzymes associated with the hydrolysis of cellulose and the oxidation of lignin, leading to reduced rates of soil CO2 and CH4 production. The effects of long-term saltwater additions contrasted with the effects of short-term exposure to brackish water during three-day laboratory incubations, which increased rates of CO2 production but lowered rates of CH4 production. Collectively, our data suggest that the long-term effect of saltwater intrusion on soil CO2 production is indirect, mediated through the effects of elevated salinity on the quantity and quality of autochthonous organic matter inputs to the soil. In contrast, salinity, organic matter content, and enzyme activities directly influence CH4 production. Our analyses demonstrate that saltwater intrusion into tidal freshwater marshes affects the entire process of carbon mineralization, from the availability of organic carbon through its terminal metabolism to CO2 and/or CH4, and illustrate that long-term shifts in biogeochemical functioning are not necessarily consistent with short-term disturbance-type responses.
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NASA Astrophysics Data System (ADS)
Neubauer, S. C.; Franklin, R. B.; Berrier, D. J.
2013-12-01
Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced ~ 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellular enzyme activity associated with organic matter breakdown, and determined potential rates of anaerobic carbon dioxide (CO2) and methane (CH4) production. Soils from the field plots treated with brackish water had lower carbon content and higher C : N ratios than soils from freshwater plots, indicating that saltwater intrusion reduced carbon availability and increased organic matter recalcitrance. This was reflected in reduced activities of enzymes associated with the hydrolysis of cellulose and the oxidation of lignin, leading to reduced rates of soil CO2 and CH4 production. The effects of long-term saltwater additions contrasted with the effects of short-term exposure to brackish water during three-day laboratory incubations, which increased rates of CO2 production but lowered rates of CH4 production. Collectively, our data suggest that the long-term effect of saltwater intrusion on soil CO2 production is indirect, mediated through the effects of elevated salinity on the quantity and quality of autochthonous organic matter inputs to the soil. In contrast, salinity, organic matter content, and enzyme activities directly influence CH4 production. Our analyses demonstrate that saltwater intrusion into tidal freshwater marshes affects the entire process of carbon mineralization, from the availability of organic carbon through its terminal metabolism to CO2 and/or CH4, and illustrate that long-term shifts in biogeochemical functioning are not necessarily consistent with short-term disturbance-type responses.
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Dietary options and behavior suggested by plant biomarker evidence in an early human habitat
NASA Astrophysics Data System (ADS)
Magill, Clayton R.; Ashley, Gail M.; Domínguez-Rodrigo, Manuel; Freeman, Katherine H.
2016-03-01
The availability of plants and freshwater shapes the diets and social behavior of chimpanzees, our closest living relative. However, limited evidence about the spatial relationships shared between ancestral human (hominin) remains, edible resources, refuge, and freshwater leaves the influence of local resources on our species' evolution open to debate. Exceptionally well-preserved organic geochemical fossils-biomarkers-preserved in a soil horizon resolve different plant communities at meter scales across a contiguous 25,000 m2 archaeological land surface at Olduvai Gorge from about 2 Ma. Biomarkers reveal hominins had access to aquatic plants and protective woods in a patchwork landscape, which included a spring-fed wetland near a woodland that both were surrounded by open grassland. Numerous cut-marked animal bones are located within the wooded area, and within meters of wetland vegetation delineated by biomarkers for ferns and sedges. Taken together, plant biomarkers, clustered bone debris, and hominin remains define a clear spatial pattern that places animal butchery amid the refuge of an isolated forest patch and near freshwater with diverse edible resources.
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The effects of Antarctic iceberg calving-size distribution in a global climate model
NASA Astrophysics Data System (ADS)
Stern, A. A.; Adcroft, A.; Sergienko, O.
2016-08-01
Icebergs calved from the Antarctic continent act as moving sources of freshwater while drifting in the Southern Ocean. The lifespan of these icebergs strongly depends on their original size during calving. In order to investigate the effects (if any) of the calving size of icebergs on the Southern Ocean, we use a coupled general circulation model with an iceberg component. Iceberg calving length is varied from 62 m up to 2.3 km, which is the typical range used in climate models. Results show that increasing the size of calving icebergs leads to an increase in the westward iceberg freshwater transport around Antarctica. In simulations using larger icebergs, the reduced availability of meltwater in the Amundsen and Bellingshausen Seas suppresses the sea-ice growth in the region. In contrast, the increased iceberg freshwater transport leads to increased sea-ice growth around much of the East Antarctic coastline. These results suggest that the absence of large tabular icebergs with horizontal extent of tens of kilometers in climate models may introduces systematic biases in sea-ice formation, ocean temperatures, and salinities around Antarctica.
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Schramm, H.L.; Gerard, P.D.; Gill, D.A.
2003-01-01
We measured the importance of 24 fishing site attributes to Mississippi freshwater anglers. Factor analysis identified four multiattribute factors as important in the selection of fishing location: CLEAN ENVIRONMENT CATCH, COST AND HARVEST and AMENITIES AND SAFETY. In general, the importance of site selection factors differed little among anglers grouped by preferred type of fish, preferred fishing location (lakes and reservoirs, rivers and streams, ponds, or reservoir tailwaters), usual manner of fishing (engine-powered boat, nonpowered boat, or shore), or change in fishing frequency. COST AND HARVEST was more important to anglers with high harvest orientations. We found low correlations between site selection factor importance scores and angler age, fishing frequency, fishing expenditures, or fishing motivation factors. We suggest that the general lack of differences in site selection factors among angler groups indicates that management strategies to improve fishing site attributes should benefit all angler groups. Clean fishing environments and awareness of the availability of desired sport fishes were "very" or "extremely" important to fishing site selection by more than 70% of Mississippi freshwater anglers and should be priority management objectives.
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40 CFR 35.1615 - Substate agreements.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Substate agreements. 35.1615 Section 35... STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1615 Substate agreements. States may make financial assistance available to substate agencies...
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40 CFR 35.1615 - Substate agreements.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Substate agreements. 35.1615 Section 35... STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned Freshwater Lakes § 35.1615 Substate agreements. States may make financial assistance available to substate agencies...
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Analysis of Water Use and Water Scarcity in Arid and Semi-arid Regions
NASA Astrophysics Data System (ADS)
Samayoa, S. D.
2017-12-01
Analysis of Water Use and Water Scarcity in Arid and Semi-arid Regions Susana Samayoa , Muhammed A. G. Chowdhury, Tushar Sinha Department of Environmental Engineering, Texas A & M University - Kingsville Freshwater sustainability in arid and semi-arid regions is highly uncertain under increasing demands due to population growth and urban development as well as limited water supply. In particular, six largest cities by population among the top twenty U.S. cities are located in Texas (TX), which also experience high variability in water availability due to frequent droughts and floods. Similarly, several regions in Arizona (AZ) are rapidly growing (e.g. Phoenix and Tucson) despite receiving scanty rainfall. Thus, the goal of this study is to analyze water use and water scarcity in watersheds within TX and AZ between 1985 and 2010. The water use data from U.S. Geological Survey (USGS) is analyzed by Hydrological Unit Code (HUC) - 8 within TX and AZ. Total freshwater use by county during 1985 and 2010 were converted into water use by HUC-8 using geospatial analysis. Water availability will be estimated by using a large scale Variable Infiltration Capacity (VIC) hydrologic model. The VIC model will be calibrated and validated for multiple basins located in Texas and Arizona. The VIC model simulated total streamflow will be aggregated across the 1/8 degree grids that are within each HUC-8 to estimate water supply. The excess water for upstream HUC-8s (= local supply minus demands) will be routed, in addition to locally generated streamflow, to estimate water availability in downstream HUC-8s. Water Scarcity Index, defined as the ratio of total freshwater demand to supply, will be estimated during 1985 and 2010 to evaluate the effects of water availability and demands on scarcity. Finally, water scarcity and use will be analyzed by HUC-8s within TX and AZ. Such information could be useful in water resources management and planning. Keywords: Water scarcity, water use, water supply, VIC
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Franson, J. Christian
2015-01-01
Exposure to lead and petroleum has caused deaths of sea ducks, but relatively few contaminants have been shown to cause mortality or be associated with population level effects. This chapter focuses primarily on field reports of contaminant concentrations in tissues of sea ducks in North America and Europe and results of some pertinent experimental studies. Much of the available interpretive data for contaminants in waterfowl come from studies of freshwater species. Limits of available data present a challenge for managers interested in sea ducks because field reports have shown that marine birds may carry greater burdens of some pollutants than freshwater species, particularly metals. It is important, then, to distinguish poisoning due to a particular contaminant as a cause of death in sea ducks versus simple exposure based solely on tissue residues. A comprehensive approach that incorporates information on field circumstances, any observed clinical signs and lesions, and tissues residues is recommended when evaluating contaminant concentrations in sea ducks.
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2018-01-01
A sandstone outcrop exposed to freshwater seepage supports a diverse assemblage of photosynthetic microbes. Dominant taxa are two cyanophytes (Oscillatoria sp., Rivularia sp.) and a unicellular green alga (Palmellococcus sp.). Less abundant taxa include a filamentous green alga, Microspora, and the desmid Cosmarium. Biologic activity is evidenced by measured levels of chlorophyll and lipids. Bioassay methods confirm the ability of these microbes to dissolve and metabolize Fe from ferruginous minerals. Chromatographic analysis reveals citric acid as the likely chelating agent; this low molecular weight organic acid is detectable in interstitial fluid in the sandstone, measured as 0.0756 mg/mL. Bioassays using a model organism, Synechoccus elongates strain UTEX 650, show that Fe availability varies among different ferruginous minerals. In decreasing order of Fe availability: magnetite > limonite > biotite > siderite > hematite. Biotite was selected for detailed study because it is the most abundant iron-bearing mineral in the sandstone. SEM images support the microbiologic evidence, showing weathering of biotite compared to relatively undamaged grains of other silicate minerals. PMID:29342973
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Vollmer, Derek; Shaad, Kashif; Souter, Nicholas J; Farrell, Tracy; Dudgeon, David; Sullivan, Caroline A; Fauconnier, Isabelle; MacDonald, Glen M; McCartney, Matthew P; Power, Alison G; McNally, Amy; Andelman, Sandy J; Capon, Timothy; Devineni, Naresh; Apirumanekul, Chusit; Ng, Cho Nam; Rebecca Shaw, M; Wang, Raymond Yu; Lai, Chengguang; Wang, Zhaoli; Regan, Helen M
2018-06-15
Degradation of freshwater ecosystems and the services they provide is a primary cause of increasing water insecurity, raising the need for integrated solutions to freshwater management. While methods for characterizing the multi-faceted challenges of managing freshwater ecosystems abound, they tend to emphasize either social or ecological dimensions and fall short of being truly integrative. This paper suggests that management for sustainability of freshwater systems needs to consider the linkages between human water uses, freshwater ecosystems and governance. We present a conceptualization of freshwater resources as part of an integrated social-ecological system and propose a set of corresponding indicators to monitor freshwater ecosystem health and to highlight priorities for management. We demonstrate an application of this new framework -the Freshwater Health Index (FHI) - in the Dongjiang River Basin in southern China, where stakeholders are addressing multiple and conflicting freshwater demands. By combining empirical and modeled datasets with surveys to gauge stakeholders' preferences and elicit expert information about governance mechanisms, the FHI helps stakeholders understand the status of freshwater ecosystems in their basin, how ecosystems are being manipulated to enhance or decrease water-related services, and how well the existing water resource management regime is equipped to govern these dynamics over time. This framework helps to operationalize a truly integrated approach to water resource management by recognizing the interplay between governance, stakeholders, freshwater ecosystems and the services they provide. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.
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Villar-Argaiz, Manuel; Medina-Sánchez, Juan M.; Biddanda, Bopaiah A.; Carrillo, Presentación
2018-01-01
A continuing challenge for scientists is to understand how multiple interactive stressor factors affect biological interactions, and subsequently, ecosystems–in ways not easily predicted by single factor studies. In this review, we have compiled and analyzed available research on how multiple stressor pairs composed of temperature (T), light (L), ultraviolet radiation (UVR), nutrients (Nut), carbon dioxide (CO2), dissolved organic carbon (DOC), and salinity (S) impact the stoichiometry of autotrophs which in turn shapes the nature of their ecological interactions within lower trophic levels in streams, lakes and oceans. Our analysis from 66 studies with 320 observations of 11 stressor pairs, demonstrated that non-additive responses predominate across aquatic ecosystems and their net interactive effect depends on the stressor pair at play. Across systems, there was a prevalence of antagonism in freshwater (60–67% vs. 47% in marine systems) compared to marine systems where synergism was more common (49% vs. 33–40% in freshwaters). While the lack of data impeded comparisons among all of the paired stressors, we found pronounced system differences for the L × Nut interactions. For this interaction, our data for C:P and N:P is consistent with the initial hypothesis that the interaction was primarily synergistic in the oceans, but not for C:N. Our study found a wide range of variability in the net effects of the interactions in freshwater systems, with some observations supporting antagonism, and others synergism. Our results suggest that the nature of the stressor pairs interactions on C:N:P ratios regulates the “continuum” commensalistic-competitive-predatory relationship between algae and bacteria and the food chain efficiency at the algae-herbivore interface. Overall, the scarce number of studies with even more fewer replications in each study that are available for freshwater systems have prevented a more detailed, insightful analysis. Our findings highlighting the preponderance of antagonistic and synergistic effects of stressor interactions in aquatic ecosystems—effects that play key roles in the functioning of feedback loops in the biosphere—also stress the need for further studies evaluating the interactive effects of multiple stressors in a rapidly changing world facing a confluence of tipping points. PMID:29441051
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Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review
Morales-Ramírez, Álvaro; Suárez-Morales, Eduardo; Corrales-Ugalde, Marco; Garrote, Octavio Esquivel
2014-01-01
Abstract The studies on marine copepods of Costa Rica started in the 1990’s and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance of the inland copepod fauna of Costa Rica requires more detailed surveys. PMID:25561828
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Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review.
Morales-Ramírez, Álvaro; Suárez-Morales, Eduardo; Corrales-Ugalde, Marco; Garrote, Octavio Esquivel
2014-01-01
The studies on marine copepods of Costa Rica started in the 1990's and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance of the inland copepod fauna of Costa Rica requires more detailed surveys.
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Scenarios reveal pathways to sustain future ecosystem services in an agricultural landscape.
Qiu, Jiangxiao; Carpenter, Stephen R; Booth, Eric G; Motew, Melissa; Zipper, Samuel C; Kucharik, Christopher J; Chen, Xi; Loheide, Steven P; Seifert, Jenny; Turner, Monica G
2018-01-01
Sustaining food production, water quality, soil retention, flood, and climate regulation in agricultural landscapes is a pressing global challenge given accelerating environmental changes. Scenarios are stories about plausible futures, and scenarios can be integrated with biophysical simulation models to explore quantitatively how the future might unfold. However, few studies have incorporated a wide range of drivers (e.g., climate, land-use, management, population, human diet) in spatially explicit, process-based models to investigate spatial-temporal dynamics and relationships of a portfolio of ecosystem services. Here, we simulated nine ecosystem services (three provisioning and six regulating services) at 220 × 220 m from 2010 to 2070 under four contrasting scenarios in the 1,345-km 2 Yahara Watershed (Wisconsin, USA) using Agro-IBIS, a dynamic model of terrestrial ecosystem processes, biogeochemistry, water, and energy balance. We asked (1) How does ecosystem service supply vary among alternative future scenarios? (2) Where on the landscape is the provision of ecosystem services most susceptible to future social-ecological changes? (3) Among alternative future scenarios, are relationships (i.e., trade-offs, synergies) among food production, water, and biogeochemical services consistent over time? Our results showed that food production varied substantially with future land-use choices and management, and its trade-offs with water quality and soil retention persisted under most scenarios. However, pathways to mitigate or even reverse such trade-offs through technological advances and sustainable agricultural practices were apparent. Consistent relationships among regulating services were identified across scenarios (e.g., trade-offs of freshwater supply vs. flood and climate regulation, and synergies among water quality, soil retention, and climate regulation), suggesting opportunities and challenges to sustaining these services. In particular, proactive land-use changes and management may buffer water quality against undesirable future climate changes, but changing climate may overwhelm management efforts to sustain freshwater supply and flood regulation. Spatially, changes in ecosystem services were heterogeneous across the landscape, underscoring the power of local actions and fine-scale management. Our research highlights the value of embracing spatial and temporal perspectives in managing ecosystem services and their complex interactions, and provides a system-level understanding for achieving sustainability of the food-water-climate nexus in agricultural landscapes. © 2017 by the Ecological Society of America.
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NASA Astrophysics Data System (ADS)
Ricko, M.; Birkett, C. M.; Beckley, B. D.
2017-12-01
The NASA/USDA Global Reservoir and Lake Monitor (G-REALM) offers multi-mission satellite radar altimetry derived surface water level products for a subset of large reservoirs, lakes, and wetlands. These products complement the in situ networks by providing stage information at un-gauged locations, and filling existing data gaps. The availability of both satellite-based rainfall (e.g., TRMM, GPCP) and surface water level products offers great opportunities to estimate and monitor additional hydrologic properties of the lake/reservoir systems. A simple water balance model relating the net freshwater flux over a catchment basin to the lake/reservoir level has been previously utilized (Ricko et al., 2011). The applicability of this approach enables the construction of a longer record of surface water level, i.e. improving the climate data record. As instrument technology and data availability evolve, this method can be used to estimate the water level of a greater number of water bodies, and a greater number of much smaller targets. In addition, such information can improve water balance estimation in different lake, reservoir, wetland, and river systems, and be very useful for assessment of improved prediction of surface water availability. Connections to climatic variations on inter-annual to inter-decadal time-scales are explored here, with a focus on a future ability to predict changes in storage volume for water resources or natural hazards concerns.
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Removal of algal blooms from freshwater by the coagulation-magnetic separation method.
Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck
2013-01-01
This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups.
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NASA Astrophysics Data System (ADS)
Trancart, Thomas; Feunteun, Eric; Lefrançois, Christel; Acou, Anthony; Boinet, Christophe; Carpentier, Alexandre
2016-05-01
In the past several years, all numerical models have forecasted an increase in extreme climatic events linked to global change. Estuarine waters at the interface of marine and freshwater bodies are among the most volatile ecosystems, particularly for aquatic species, and will be strongly influenced by the temperature with extreme flooding events. This study aimed to quantify the acclimation capacity of coastal fish species to estuarine plume modifications. The thicklip mullet (Chelon labrosus) and European seabass (Dicentrarchus labrax) were selected as representative species of estuarine ecological guilds. These fish were subjected to an experiment mimicking a brief freshwater intrusion (35-5). These experiments were conducted at two different temperatures that these two species would encounter during their incursion from the sea through estuarine waters to freshwater habitats. The experimental results confirmed the high capacity for acclimation of both species to changes in salinity and temperature. Interspecific differences were observed. For example, the salinity has a greater effect on the metabolism of the seabass than on that of the mullets. Meanwhile, the temperature has a greater effect on the mullets. These differences in metabolic responses to fluctuating salinities and temperatures may modify the use of estuarine waters by these species and should be considered when predicting future specific distribution areas in the context of global change.
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Water Use in Florida, 2005 and Trends 1950-2005
Marella, Richard L.
2008-01-01
Water is among Florida's most valued resources. The State has more than 1,700 streams and rivers, 7,800 freshwater lakes, 700 springs, 11 million acres of wetlands, and underlying aquifers yielding quantities of freshwater necessary for both human and environmental needs (Fernald and Purdum, 1998). Although renewable, these water resources are finite, and continued growth in population, tourism, and agriculture will place increased demands on these water supplies. The permanent population of Florida in 2005 totaled 17.9 million, ranking fourth in the Nation (University of Florida, 2006); nearly 86 million tourists visited the State (Orlando Business Journal, 2006). In 2005, Florida harvested two-thirds of the total citrus production in the United States and ranked fifth in the Nation net farm income (Florida Department of Agriculture and Consumer Services, 2006). Freshwater is vital for sustaining Florida's population, economy, and agricultural production. Accurate estimates reflecting water use and trends in Florida are compiled in 5-year intervals by the U.S. Geological Survey (USGS) in cooperation with the Florida Department of Environmental Protection (FDEP) and the Northwest Florida, St. Johns River, South Florida, Southwest Florida, and Suwannee River Water Management Districts (Marella, 2004). This coordinated effort provides the necessary data and information for planning future water needs and resource management. The purpose of this fact sheet is to present the highlights of water use in Florida for 2005 along with some significant trends in withdrawals since 1950.
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Multidimensional approach to invasive species prevention.
Briski, Elizabeta; Allinger, Lisa E; Balcer, Mary; Cangelosi, Allegra; Fanberg, Lana; Markee, Tom P; Mays, Nicole; Polkinghorne, Christine N; Prihoda, Kelsey R; Reavie, Euan D; Regan, Deanna H; Reid, Donald M; Saillard, Heidi J; Schwerdt, Tyler; Schaefer, Heidi; TenEyck, Matthew; Wiley, Chris J; Bailey, Sarah A
2013-02-05
Nonindigenous species (NIS) cause global biotic homogenization and extinctions, with commercial shipping being a leading vector for spread of aquatic NIS. To reduce transport of NIS by ships, regulations requiring ballast water exchange (BWE) have been implemented by numerous countries. BWE appears to effectively reduce risk for freshwater ports, but provides only moderate protection of marine ports. In the near future, ships may be required to undertake ballast water treatment (BWT) to meet numeric performance standards, and BWE may be phased out of use. However, there are concerns that BWT systems may not operate reliably in fresh or turbid water, or both. Consequently, it has been proposed that BWE could be used in combination with BWT to maximize the positive benefits of both management strategies for protection of freshwater ports. We compared the biological efficacy of "BWE plus BWT" against "BWT alone" at a ballast water treatment experimental test facility. Our comparative evaluation showed that even though BWT alone significantly reduced abundances of all tested organism groups except total heterotrophic bacteria, the BWE plus BWT strategy significantly reduced abundances for all groups and furthermore resulted in significantly lower abundances of most groups when compared to BWT alone. Our study clearly demonstrates potential benefits of combining BWE with BWT to reduce invasion risk of freshwater organisms transported in ships' ballast water, and it should be of interest to policy makers and environmental managers.
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Environmental factors that influence cyanobacteria and geosmin occurrence in reservoirs
Journey, Celeste A.; Beaulieu, Karen M.; Bradley, Paul M.
2013-01-01
Phytoplankton are small to microscopic, free-floating algae that inhabit the open water of freshwater, estuarine, and saltwater systems. In freshwater lake and reservoirs systems, which are the focus of this chapter, phytoplankton communities commonly consist of assemblages of the major taxonomic groups, including green algae, diatoms, dinoflagellates, and cyanobacteria. Cyanobacteria are a diverse group of single-celled organisms that can exist in a wide range of environments, not just open water, because of their adaptability [1-3]. It is the adaptability of cyanobacteria that enables this group to dominate the phytoplankton community and even form nuisance or harmful blooms under certain environmental conditions [3-6]. In fact, cyanobacteria are predicted to adapt favorably to future climate change in freshwater systems compared to other phytoplankton groups because of their tolerance to rising temperatures, enhanced vertical thermal stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns [7, 8]. Understanding those environmental conditions that favor cyanobacterial dominance and bloom formation has been the focus of research throughout the world because of the concomitant production and release of nuisance and toxic cyanobacterial-derived compounds [4-6, 7-10]. However, the complex interaction among the physical, chemical, and biological processes within lakes, reservoirs, and large rivers often makes it difficult to identify primary environmental factors that cause the production and release of these cyanobacterial by-products.
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Environmental factors that influence cyanobacteria and geosmin occurrence in reservoirs
Journey, Celeste A.; Beaulieu, Karen M.; Bradley, Paul M.; Bradley, Paul M.
2013-01-01
Phytoplankton are small to microscopic, free-floating algae that inhabit the open water of freshwater, estuarine, and saltwater systems. In freshwater lake and reservoirs systems, which are the focus of this chapter, phytoplankton communities commonly consist of assemblages of the major taxonomic groups, including green algae, diatoms, dinoflagellates, and cyanobacteria. Cyanobacteria are a diverse group of single-celled organisms that can exist in a wide range of environments, not just open water, because of their adaptability [1-3]. It is the adaptability of cyanobacteria that enables this group to dominate the phytoplankton community and even form nuisance or harmful blooms under certain environmental conditions [3-6]. In fact, cyanobacteria are predicted to adapt favorably to future climate change in freshwater systems compared to other phytoplankton groups because of their tolerance to rising temperatures, enhanced vertical thermal stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns [7, 8]. Understanding those environmental conditions that favor cyanobacterial dominance and bloom formation has been the focus of research throughout the world because of the concomitant production and release of nuisance and toxic cyanobacterial-derived compounds [4-6, 7-10]. However, the complex interaction among the physical, chemical, and biological processes within lakes, reservoirs, and large rivers often makes it difficult to identify primary environmental factors that cause the production and release of these cyanobacterial by-products [9].
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NASA Technical Reports Server (NTRS)
Kirk, Donnie; Wolfe, Amy; Ba, Adama; Nyquist, Mckenzie; Rhodes, Tyler; Toner, Caitlin; Cabosky, Rachel; Gotschalk, Emily; Gregory, Brad; Kendall, Candace
2016-01-01
Mangroves act as a transition zone between fresh and salt water habitats by filtering and indicating salinity levels along the coast of the Florida Everglades. However, dredging and canals built in the early 1900s depleted the Everglades of much of its freshwater resources. In an attempt to assist in maintaining the health of threatened habitats, efforts have been made within Everglades National Park to rebalance the ecosystem and adhere to sustainably managing mangrove forests. The Everglades Ecological Forecasting II team utilized Google Earth Engine API and satellite imagery from Landsat 5, 7, and 8 to continuously create land-change maps over a 25 year period, and to allow park officials to continue producing maps in the future. In order to make the process replicable for project partners at Everglades National Park, the team was able to conduct a supervised classification approach to display mangrove regions in 1995, 2000, 2005, 2010 and 2015. As freshwater was depleted, mangroves encroached further inland and freshwater marshes declined. The current extent map, along with transition maps helped create forecasting models that show mangrove encroachment further inland in the year 2030 as well. This project highlights the changes to the Everglade habitats in relation to a changing climate and hydrological changes throughout the park.
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NASA Astrophysics Data System (ADS)
Falfushynska, Halina I.; Phan, Tuan; Sokolova, Inna M.
2016-12-01
Global climate change (GCC) can negatively affect freshwater ecosystems. However, the degree to which freshwater populations can acclimate to long-term warming and the underlying molecular mechanisms are not yet fully understood. We used the cooling water discharge (CWD) area of a power plant as a model for long-term warming. Survival and molecular stress responses (expression of molecular chaperones, antioxidants, bioenergetic and protein synthesis biomarkers) to experimental warming (20-41 °C, +1.5 °C per day) were assessed in invasive clams Corbicula fluminea from two pristine populations and a CWD population. CWD clams had considerably higher (by ~8-12 °C) lethal temperature thresholds than clams from the pristine areas. High thermal tolerance of CWD clams was associated with overexpression of heat shock proteins HSP70, HSP90 and HSP60 and activation of protein synthesis at 38 °C. Heat shock response was prioritized over the oxidative stress response resulting in accumulation of oxidative lesions and ubiquitinated proteins during heat stress in CWD clams. Future studies should determine whether the increase in thermal tolerance in CWD clams are due to genetic adaptation and/or phenotypic plasticity. Overall, our findings indicate that C. fluminea has potential to survive and increase its invasive range during warming such as expected during GCC.
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Breyta, Rachel; Brito, Ilana L.; Ferguson, Paige; Kurath, Gael; Naish, Kerry A.; Purcell, Maureen; Wargo, Andrew R.; LaDeau, Shannon L.
2017-01-01
This is the first comprehensive region wide, spatially explicit epidemiologic analysis of surveillance data of the aquatic viral pathogen infectious hematopoietic necrosis virus (IHNV) infecting native salmonid fish. The pathogen has been documented in the freshwater ecosystem of the Pacific Northwest of North America since the 1950s, and the current report describes the disease ecology of IHNV during 2000–2012. Prevalence of IHNV infection in monitored salmonid host cohorts ranged from 8% to 30%, with the highest levels observed in juvenile steelhead trout. The spatial distribution of all IHNV-infected cohorts was concentrated in two sub-regions of the study area, where historic burden of the viral disease has been high. During the study period, prevalence levels fluctuated with a temporal peak in 2002. Virologic and genetic surveillance data were analyzed for evidence of three separate but not mutually exclusive transmission routes hypothesized to be maintaining IHNV in the freshwater ecosystem. Transmission between year classes of juvenile fish at individual sites (route 1) was supported at varying levels of certainty in 10%–55% of candidate cases, transmission between neighboring juvenile cohorts (route 2) was supported in 31%–78% of candidate cases, and transmission from adult fish returning to the same site as an infected juvenile cohort was supported in 26%–74% of candidate cases. The results of this study indicate that multiple specific transmission routes are acting to maintain IHNV in juvenile fish, providing concrete evidence that can be used to improve resource management. Furthermore, these results demonstrate that more sophisticated analysis of available spatio-temporal and genetic data is likely to yield greater insight in future studies.
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Sectoral contributions to surface water stress in the coterminous United States
NASA Astrophysics Data System (ADS)
Averyt, K.; Meldrum, J.; Caldwell, P.; Sun, G.; McNulty, S.; Huber-Lee, A.; Madden, N.
2013-09-01
Here, we assess current stress in the freshwater system based on the best available data in order to understand possible risks and vulnerabilities to regional water resources and the sectors dependent on freshwater. We present watershed-scale measures of surface water supply stress for the coterminous United States (US) using the water supply stress index (WaSSI) model which considers regional trends in both water supply and demand. A snapshot of contemporary annual water demand is compared against different water supply regimes, including current average supplies, current extreme-year supplies, and projected future average surface water flows under a changing climate. In addition, we investigate the contributions of different water demand sectors to current water stress. On average, water supplies are stressed, meaning that demands for water outstrip natural supplies in over 9% of the 2103 watersheds examined. These watersheds rely on reservoir storage, conveyance systems, and groundwater to meet current water demands. Overall, agriculture is the major demand-side driver of water stress in the US, whereas municipal stress is isolated to southern California. Water stress introduced by cooling water demands for power plants is punctuated across the US, indicating that a single power plant has the potential to stress water supplies at the watershed scale. On the supply side, watersheds in the western US are particularly sensitive to low flow events and projected long-term shifts in flow driven by climate change. The WaSSI results imply that not only are water resources in the southwest in particular at risk, but that there are also potential vulnerabilities to specific sectors, even in the ‘water-rich’ southeast.
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Bril, Jeremy S.; Durst, Jonathan J.; Hurley, Brion M.; Just, Craig L.; Newton, Teresa J.
2014-01-01
Native freshwater mussels can influence the aquatic N cycle, but the mechanisms and magnitude of this effect are not fully understood. We assessed the effects of Amblema plicata and Lampsilis cardium on N transformations over 72 d in 4 continuous-flow mesocosms, with 2 replicates of 2 treatments (mesocosms with and without mussels), equipped with electronic water-chemistry sensors. We compared sensor data to discrete sample data to assess the effect of additional sensor measurements on the ability to detect mussel-related effects on NO3– formation. Analysis of 624 sensor-based data points detected a nearly 6% increase in NO3– concentration in overlying water of mesocosms with mussels relative to mesocosms without mussels (p 3– between treatments. Mussels also significantly increased NO2– concentrations in the overlying water, but no significant difference in total N was observed. We used the sensor data for phytoplankton-N and NH4+ to infer that digestion times in mussels were 13 ± 6 h. The results suggest that rapid increases in phytoplankton-N levels in the overlying water can lead to decreased lag times between phytoplankton-N and NH4+ maxima. This result indicates that mussels may adjust their digestion rates in response to increased levels of food. The adjustment in digestion time suggests that mussels have a strong response to food availability that can disrupt typical circadian rhythms. Use of sensor data to measure directly and to infer mussel effects on aquatic N transformations at the mesocosm scale could be useful at larger scales in the future.
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Changes to Watershed Hydrology due to Changing Snowmelt Patterns, Michigan, US
NASA Astrophysics Data System (ADS)
Ford, C.; Kendall, A. D.; Hyndman, D. W.
2017-12-01
With increasing temperatures and changing precipitation patterns associated with global climate change, the future of hydrologic resources related to snowmelt is less certain than ever. Most existing snowmelt hydrology research focuses on mountainous regions such as the western United States, where snowpack is a primary reservoir of available freshwater. Less research has been done on snowmelt hydrology in non-mountainous, temperate middle to upper latitude regions such as the Midwestern US, where snowmelt is still an important contributor to water budgets (and critically summer water supplies). This study examines the changes to watershed hydrology due to changing snowmelt patterns in Michigan, which has a tension line between seasonally-persistent snowpacks in the north, and episodic snowpacks in the south. This transition varies in space and time, and is likely moving northward as a consequence of climate change. Changes to snow and winter weather were statistically determined from output of the NOAA's Snow Data Assimilation System (SNODAS) model along with historical weather data from the Global Historical Climatology Network. Stream data from the USGS, combined with in-house monitoring data from groundwater and soil moisture networks provide insight into the hydrologic changes. Snowmelt in years with warmer winter temperatures tend to end earlier in the year, resulting in earlier peak stream flows. These changes become more noticeable in the northern regions of the state, where snowfall amounts can be amongst the largest in the country. This study also examines the changing spatial transition zone between regions with snow lasting throughout the season and regions with a more episodic snow presence. In an area with some of the largest freshwater resources in the world, significant changes to streamflow and groundwater recharge could impact already stressed ecosystems and local water supplies.
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Recent changes in ecologically-relevant streamflows in North America
NASA Astrophysics Data System (ADS)
Ficklin, D. L.; Abatzoglou, J. T.; Knouft, J.; Robeson, S. M.
2017-12-01
The streamflow regime is a primary regulator of the composition and functioning of freshwater ecosystems. Growth, behavior, and/or reproduction of most freshwater organisms are influenced in some way by the amount of water, including high and low flows, and seasonal fluctuations in water availability in a particular habitat. This work examines trends in ecologically-relevant measures of streamflows from 1980-2015 for over 3,000 streamflow gauges located throughout Canada and United States. Specifically, we examine trends in water year mean flow and variability, as well as trends in high (95th and 99th percentile), low (1st and 5th percentile), and 7- and 3-day maximum and minimum streamflows. The results indicate a clear regional delineation of significant increases of ecologically-relevant streamflows in the northern Central Plains/south-central Canada, upper Midwest (except Michigan and Wisconsin) and northeastern United States/southeastern Canada, while significant decreases are found throughout the southeastern and southwestern United States. The regional agreement between streamflow trends in regulated and unregulated watersheds indicate a widespread climatic influence that is not masked by human alteration of streamflows. We explore the degree to which climate factors explain both interannual variability and observed trends in streamflow to better elucidate the role of top-down climate drivers versus bottom-up land surface drivers on recent trends in ecologically-relevant streamflow. We also explore how these changes in streamflow are affecting water quality such as water temperature and sediment concentration. This type of analysis will aid in highlighting streamflow regions in the United States that are currently sensitive to changes in climate, but may also aid in understanding which regions may be sensitive to future climatic changes.
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Future Climate Change Impacts on Surface Hydrology over Texas River Basins
NASA Astrophysics Data System (ADS)
Lee, K.; Gao, H.; Huang, M.; Sheffield, J.
2014-12-01
Future freshwater availability is a pressing issue in Texas due to frequent drought events and fast population growth. Even though the science community has well investigated future temperature trends, it is still unclear whether precipitation will increase or decrease in this region. Furthermore, there is a lack of understanding on how the changing climate will affect water resources across different spatial-temporal scales. This study aims to quantify the impacts of climate change on surface hydrology at the basin scale under different future emission scenarios. The Variable Infiltration Capacity (VIC) model, forced by an ensemble of statistically downscaled climate projections from the Coupled Model Intercomparison Project Phase 5 (CMIP5) models, is employed to predict the future hydrology. The VIC model parameters are adopted from the North American Land Data Assimilation System (NLDAS) at a spatial resolution of 1/8°. The CMIP5 projections contain four different scenarios in terms of Representative Concentration Pathway (RCP) (i.e. 2.6, 4.5, 6.0 and 8.5 w/m2). The analysis is carried out in three steps. First, the observed streamflows are used to evaluate the performance of VIC simulations forced by CMIP5 models during historical period. Second, VIC outputs under multiple CMIP5 model scenarios from 1950 to 2099 are analyzed to identify how soil moisture, evapotranspiration, runoff, and routed streamflows change in time and space. Third, the spatial patterns of seasonal temperature, seasonal precipitation, and the Palmer Drought Severity Index (PDSI)—over four 20-year periods (1980-1999, 2010-2029, 2040-2059 and 2080-2099)—are used to pinpoint the regions that will be most affected by climate change (among the 13 Texan river basins). Furthermore, the role of groundwater in meeting the increasing needs for water supply is discussed. The results are expected to contribute to various future water resources management decisions in Texas.
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NASA Astrophysics Data System (ADS)
Bucak, T.; Trolle, D.; Andersen, H. E.; Thodsen, H.; Erdoğan, Ş.; Levi, E. E.; Filiz, N.; Jeppesen, E.; Beklioğlu, M.
2016-12-01
Inter- and intra-annual water level fluctuations and change in water flow regime are intrinsic characteristics of Mediterranean lakes. However, considering the climate change projections for the water-limited Mediterranean region where potential evapotranspiration exceeds precipitation and with increased air temperatures and decreased precipitation, more dramatic water level declines in lakes and severe water scarcity problems are expected to occur in the future. Our study lake, Lake Beyşehir, the largest freshwater lake in the Mediterranean basin, is - like other Mediterranean lakes - under pressure due to water abstraction for irrigated crop farming and climatic changes, and integrated water level management is therefore required. We used an integrated modeling approach to predict the future lake water level of Lake Beyşehir in response to the future changes in both climate and, potentially, land use by linking the catchment model Soil and Water Assessment Tool (SWAT) with a Support Vector Machine Regression model (ɛ-SVR). We found that climate change projections caused enhanced potential evapotranspiration and reduced total runoff, whereas the effects of various land use scenarios within the catchment were comparatively minor. In all climate scenarios applied in the ɛ-SVR model, changes in hydrological processes caused a water level reduction, predicting that the lake may dry out already in the 2040s with the current outflow regulation considering the most pessimistic scenario. Based on model runs with optimum outflow management, a 9-60% reduction in outflow withdrawal is needed to prevent the lake from drying out by the end of this century. Our results indicate that shallow Mediterranean lakes may face a severe risk of drying out and loss of ecosystem value in near future if the current intense water abstraction is maintained. Therefore, we conclude that outflow management in water-limited regions in a warmer and drier future and sustainable use of water sources are vitally important to sustain lake ecosystems and their ecosystem services.
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Wei, Yi; d'Errico, Francesco; Vanhaeren, Marian; Li, Feng; Gao, Xing
2016-01-01
We report the discovery and present a detailed analysis of a freshwater bivalve from Shuidonggou Locality 2, layer CL3. This layer is located c. 40 cm below layer CL2, which has yielded numerous ostrich eggshell beads. The shell is identified as the valve of a Corbicula fluminea. Data on the occurrence of this species in the Shuidonggou region during Marine Isotope Stage 3 and taphonomic analysis, conducted in the framework of this study, of a modern biocoenosis and thanatocoenosis suggest that the archeological specimen was collected at one of the numerous fossil or sub-fossil outcrops where valves of this species were available at the time of occupation of level CL3. Experimental grinding and microscopic analysis of modern shells of the same species indicate that the Shuidonggou shell was most probably ground on coarse sandstone to open a hole on its umbo, attach a thread, and use the valve as a personal ornament. Experimental engraving of freshwater shells and microscopic analysis identify an incision crossing the archaeological valve outer surface as possible deliberate engraving. Reappraisal of the site chronology in the light of available radiocarbon evidence suggests an age of at least 34-33 cal kyr BP for layer CL3. Such estimate makes the C. fluminea recovered from CL3 one of the earliest instances of personal ornamentation and the earliest example of a shell bead from China.
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Peak water limits to freshwater withdrawal and use
Gleick, Peter H.; Palaniappan, Meena
2010-01-01
Freshwater resources are fundamental for maintaining human health, agricultural production, economic activity as well as critical ecosystem functions. As populations and economies grow, new constraints on water resources are appearing, raising questions about limits to water availability. Such resource questions are not new. The specter of “peak oil”—a peaking and then decline in oil production—has long been predicted and debated. We present here a detailed assessment and definition of three concepts of “peak water”: peak renewable water, peak nonrenewable water, and peak ecological water. These concepts can help hydrologists, water managers, policy makers, and the public understand and manage different water systems more effectively and sustainably. Peak renewable water applies where flow constraints limit total water availability over time. Peak nonrenewable water is observable in groundwater systems where production rates substantially exceed natural recharge rates and where overpumping or contamination leads to a peak of production followed by a decline, similar to more traditional peak-oil curves. Peak “ecological” water is defined as the point beyond which the total costs of ecological disruptions and damages exceed the total value provided by human use of that water. Despite uncertainties in quantifying many of these costs and benefits in consistent ways, more and more watersheds appear to have already passed the point of peak water. Applying these concepts can help shift the way freshwater resources are managed toward more productive, equitable, efficient, and sustainable use. PMID:20498082
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The water-energy nexus: an earth science perspective
Healy, Richard W.; Alley, William M.; Engle, Mark A.; McMahon, Peter B.; Bales, Jerad D.
2015-01-01
Relevant earth science issues analyzed and discussed herein include freshwater availability; water use; ecosystems health; assessment of saline water resources; assessment of fossil-fuel, uranium, and geothermal resources; subsurface injection of wastewater and carbon dioxide and related induced seismicity; climate change and its effect on water availability and energy production; byproducts and waste streams of energy development; emerging energy-development technologies; and energy for water treatment and delivery.
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NASA Astrophysics Data System (ADS)
Rebenack, C.; Anderson, W. T.; Cherubini, P.
2012-12-01
The South Florida coastal ecosystem is among the world's subtropical coastlines which are threatened by the potential effects of climate change. A well-developed localized paleohistory is essential in the understanding of the role climate variability/change has on both hydrological dynamics and disturbance event frequency and intensity; this understanding can then aid in the development of better predictive models. High resolution paleoclimate proxies, such as those developed from tree-ring archives, may be useful tools for extrapolating actual climate trends over time from the overlapping long-term and short-term climate cycles, such as the Atlantic Multidecadal Oscillation (AMO) and the El Niño-Southern Oscillation (ENSO). In South Florida, both the AMO and ENSO strongly influence seasonal precipitation, and a more complete grasp of how these cycles have affected the region in the past could be applied to future freshwater management practices. Dendrochronology records for the terrestrial subtropics, including South Florida, are sparse because seasonality for this region is precipitation-driven; this is in contrast to the drastic temperature changes experienced in the temperate latitudes. Subtropical seasonality may lead to the complete lack of visible rings or to the formation of ring structures that may or may not represent annual growth. Fortunately, it has recently been demonstrated that Pinus elliottii trees in South Florida produce distinct annual growth rings; however ring width was not found to significantly correlate with either the AMO or ENSO. Dendrochronology studies may be taken a step beyond the physical tree-ring proxies by using the carbon isotope ratios to infer information about physiological controls and environmental factors that affect the distribution of isotopes within the plant. It has been well established that the stable isotope composition of cellulose can be related to precipitation, drought, large-scale ocean/atmospheric oscillations, and disturbance events, such as tropical cyclone impacts. Because slash pine growth is dependent on water availability, a chronology developed using carbon isotopes may provide greater insight into plant stress over time and ultimately may lead to better correlations with climate oscillations. The work presented here is the result of a carbon-isotope study of four slash pine trees located across a freshwater gradient on Big Pine Key, Florida. A site chronology has been developed by cross-dating the δ13C records for each of the trees. The tree located on the distal edge of the freshwater gradient shows an overall enriched isotopic signature over time compared to the trees growing over a deeper part of the local freshwater lens, indicating that these trees are sensitive to water stress. In addition, the carbon isotope data show seasonal stomatal activity in the trees and indicate the timing of two disturbance events.
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NASA Astrophysics Data System (ADS)
Tall, Moustapha; Sylla, Mouhamadou Bamba; Diallo, Ismaïla; Pal, Jeremy S.; Faye, Aïssatou; Mbaye, Mamadou Lamine; Gaye, Amadou Thierno
2017-07-01
This study analyzes the impact of anthropogenic climate change in the hydroclimatology of Senegal with a focus over the lake of Guiers basin for the middle (2041-2060) and late twenty-first century (2080-2099). To this end, high-resolution multimodel ensemble based on regional climate model experiments considering two Representative Concentration Pathways (RCP4.5 and RCP8.5) is used. The results indicate that an elevated warming, leading to substantial increase of atmospheric water demand, is projected over the whole of Senegal. In the Lake basin, these increases in potential evapotranspiration (PE) range between 10 and 25 % in the near future and for RCP4.5 while for the far future and RCP8.5, they exceed 50 %. In addition, mean precipitation unveils contrasting changes with wetter (10 to 25 % more) conditions by the middle of the century and drier conditions (more than 50 %) during the late twenty-first century. Such changes cause more/less evapotranspiration and soil moisture respectively during the two future periods. Furthermore, surface runoff shows a tendency to increase in most areas amid few locations including the Lake basin with substantial reduction. Finally, it is found that while semi-arid climates develop in the RCP4.5 scenario, generalized arid conditions prevail over the whole Senegal for RCP8.5. It is thus evident that these future climate conditions substantially threaten freshwater availability for the country and irrigated cropping over the Lake basin. Therefore, strong governmental politics are needed to help design response options to cope with the challenges posed by the projected climate change for the country.
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The ecology of vector snail habitats and mosquito breeding-places
Muirhead-Thomson, R. C.
1958-01-01
The ecology of freshwater snails—in particular those which act as intermediate hosts of bilharziasis—is reviewed in the light of the much more extensive knowledge available on the breeding-places of anopheline mosquitos. Experimental ecological methods are recommended for the field and laboratory investigation of a number of common problems involved in the study of snail habitats and mosquito breeding-places. Among the environmental factors discussed are temperature, oxygen concentration, water movement, pollution and salinity. Sampling methods for estimating populations of both snails and mosquito larvae are also described. An attempt is made to show how malacologists and entomologists alike would benefit from improved facilities for keeping abreast of general developments in the wider field of freshwater ecology. PMID:13596888
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Optical sensors for water quality
Pellerin, Brian A.; Bergamaschi, Brian A.
2014-01-01
Recent advancements in commercially available in situ sensors, data platforms, and new techniques for data analysis provide an opportunity to monitor water quality in rivers, lakes, and estuaries on the time scales in which changes occur. For example, measurements that capture the variability in freshwater systems over time help to assess how shifts in seasonal runoff, changes in precipitation intensity, and increased frequencies of disturbances (such as fire and insect outbreaks) affect the storage, production, and transport of carbon and nitrogen in watersheds. Transmitting these data in real-time also provides information that can be used for early trend detection, help identify monitoring gaps, and provide sciencebased decision support across a range of issues related to water quality, freshwater ecosystems, and human health.
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-05-02
... cause (Short and Wyllie-Echeverria 1996). Throughout California, human activities including, but not... directed freshwater flows can directly and indirectly destroy eelgrass habitats. The importance of eelgrass..., monitoring programs, and reports verifying the completion of mitigation activities. Eelgrass warrants a...
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A Synopsis of Global Mapping of Freshwater Habitats and Biodiversity: Implications for Conservation
DOE Office of Scientific and Technical Information (OSTI.GOV)
McManamay, Ryan A.; Griffiths, Natalie A.; DeRolph, Christopher R.
Accurately mapping freshwater habitats and biodiversity at high-resolutions across the globe is essential for assessing the vulnerability and threats to freshwater organisms and prioritizing conservation efforts. Since the 2000s, extensive efforts have been devoted to mapping global freshwater habitats (rivers, lakes, and wetlands), the spatial representation of which has changed dramatically over time with new geospatial data products and improved remote sensing technologies. Some of these mapping efforts, however, are still coarse representations of actual conditions. Likewise, the resolution and scope of global freshwater biodiversity compilation efforts have also increased, but are yet to mirror the spatial resolution and fidelitymore » of mapped freshwater environments. In our synopsis, we find that efforts to map freshwater habitats have been conducted independently of those for freshwater biodiversity; subsequently, there is little congruence in the spatial representation and resolution of the two efforts. We suggest that global species distribution models are needed to fill this information gap; however, limiting data on habitat characteristics at scales that complement freshwater habitats has prohibited global high-resolution biogeography efforts. Emerging research trends, such as mapping habitat alteration in freshwater ecosystems and trait biogeography, show great promise in mechanistically linking global anthropogenic stressors to freshwater biodiversity decline and extinction risk.« less
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Impact of Arctic shelf summer stratification on Holocene climate variability
NASA Astrophysics Data System (ADS)
Thibodeau, Benoit; Bauch, Henning A.; Knies, Jochen
2018-07-01
Understanding the dynamic of freshwater and sea-ice export from the Arctic is crucial to better comprehend the potential near-future climate change consequences. Here, we report nitrogen isotope data of a core from the Laptev Sea to shed light on the impact of the Holocene Siberian transgression on the summer stratification of the Laptev Sea. Our data suggest that the oceanographic setting was less favourable to sea-ice formation in the Laptev Sea during the early to mid-Holocene. It is only after the sea level reached a standstill at around 4 ka that the water column structure in the Laptev Sea became more stable. Modern-day conditions, often described as "sea-ice factory", were reached about 2 ka ago, after the development of a strong summer stratification. These results are consistent with sea-ice reconstruction along the Transpolar Drift, highlighting the potential contribution of the Laptev Sea to the export of freshwater from the Arctic Ocean.
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To what extent do they sway Australian water management decision making?
NASA Astrophysics Data System (ADS)
Papas, Maureen
2016-10-01
At a time when the reliability of freshwater resources has become highly unpredictable, as a result of climate change and increased droughts frequency, the role of scientific evidence in forecasting the availability of seasonal water has become more critical. Australia is one of the driest inhabited continents. Its freshwater availability is highly variable, which poses unique problems for the management of the nation's water resources. Under Australia's federal system, water management challenges have been progressively dealt with through political institutions that rely on best available science to inform policy development. However, it could be argued that evidenced-based policy making is an impossible aim in a highly complex and uncertain political environment: that such a rational approach would be defeated by competing values and vested interests across stakeholders. This article demonstrates that, while science has a fundamental role to play in effective water resource management, the reality on the ground often diverges from the intended aim and does not always reflect efforts at reform. This article briefly reviews the Water Act 2007 (Cth) and comments on why policy makers need to manage rather than try to eliminate uncertainty to promote change.
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Water Resource Assessment in KRS Reservoir Using Remote Sensing and GIS Modelling
NASA Astrophysics Data System (ADS)
Manubabu, V. H.; Gouda, K. C.; Bhat, N.; Reddy, A.
2014-12-01
In the recent time the fresh water resource becomes very important because of various reasons like population growth, pollution, over exploitation of the ground water resources etc. As there is no efficient and proper measures for recharging ground water exists and also the climatological impacts on water resources like global warming exacerbating water shortages, growing populations and rising demand for freshwater in agriculture, industry, and energy production. There is a need and challenging task for analyzing the future changes in regional water availability and it is also very much necessary to asses and predict the fresh water present in a lake or reservoir to make better decision making in the optimal usage of surface water. In the present study is intended to provide a practical discussion of methodology that deals with how to asses and predict amount of surface water available in the future using Remote Sensing(RS) data , Geographical Information System(GIS) techniques, and GCM (Global Circulation Model). Basically the study emphasized over one of the biggest reservoir i.e. the Krishna Raja Sagara (KRS) reservoir situated in the state of Karnataka in India. Multispectral satellite images like IRS LISS III and Landsat L8 from different open source web portals like NRSC-Bhuvan and NASA Earth Explorer respectively are used for the present analysis. The multispectral satellite images are used to identify the temporal changes of the water quantity in the reservoir for the period 2000 to 2014. Also the water volume are being calculated using Advances Space born Thermal Emission and Reflection Radiometer (ASTER) Global DEM over the reservoir basin. The hydro meteorological parameters are also studied using multi-source observed data and the empirical water budget models for the reservoir in terms of rainfall, temperature, run off, water inflow and outflow etc. are being developed and analyzed. Statistical analysis are also carried out to quantify the relation between reservoir water volume and the hydrological parameters (Figure 1). A general circulation model (GCM) is used for the prediction of major hydro meteorological parameters like rainfall and using the GCM predictions the water availability in terms of water volume in future are simulated using the empirical water budget model.
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Planning and the Energy-Water Nexus
NASA Astrophysics Data System (ADS)
Tidwell, V. C.; Bailey, M.; Zemlick, K.; Moreland, B.
2015-12-01
While thermoelectric power generation accounts for only 3-5% of the nation's consumptive use of freshwater, its future potential to exert pressure on limited water supplies is of concern given projected growth in electric power generation. The corresponding thermoelectric water footprint could look significantly different depending on decisions concerning the mix of fuel type, cooling type, location, and capacity, which are influenced by such factors as fuel costs, technology evolution, demand growth, policies, and climate change. The complex interplay among these disparate factors makes it difficult to identify where water could limit siting choices for thermoelectric generation or alternatively, thermoelectric development could limit growth in other water use sectors. These arguments point to the need for joint coordination, analysis and planning between energy and water managers. Here we report on results from a variety of planning exercises spanning scales from the national, interconnection, to the utility. Results will highlight: lessons learned from the integrated planning exercises; the broad range in potential thermoelectric water use futures; regional differences in the thermoelectric-water nexus; and, opportunities for non-traditional waters to ease competition over limited freshwater supplies and to harden thermoelectric generation against drought vulnerability. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
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A comprehensive framework for the assessment of new end uses in recycled water schemes.
Chen, Zhuo; Ngo, Huu Hao; Guo, Wenshan; Lim, Richard; Wang, Xiaochang C; O'Halloran, Kelly; Listowski, Andrzej; Corby, Nigel; Miechel, Clayton
2014-02-01
Nowadays, recycled water has provided sufficient flexibility to satisfy short-term freshwater needs and increase the reliability of long-term water supplies in many water scarce areas, which becomes an essential component of integrated water resources management. However, the current applications of recycled water are still quite limited that are mainly associated with non-potable purposes such as irrigation, industrial uses, toilet flushing and car washing. There is a large potential to exploit and develop new end uses of recycled water in both urban and rural areas. This can greatly contribute to freshwater savings, wastewater reduction and water sustainability. Consequently, the paper identified the potentials for the development of three recycled water new end uses, household laundry, livestock feeding and servicing, and swimming pool, in future water use market. To validate the strengths of these new applications, a conceptual decision analytic framework was proposed. This can be able to facilitate the optional management strategy selection process and thereafter provide guidance on the future end use studies within a larger context of the community, processes, and models in decision-making. Moreover, as complex evaluation criteria were selected and taken into account to narrow down the multiple management alternatives, the methodology can successfully add transparency, objectivity and comprehensiveness to the assessment. Meanwhile, the proposed approach could also allow flexibility to adapt to particular circumstances of each case under study. © 2013.
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Dried Out: Phytoplankton Drought Response in the San Francisco Estuary
NASA Astrophysics Data System (ADS)
Dawson, T.; Houskeeper, H. F.; Palacios, S. L.; Peacock, M.; Kudela, R. M.
2017-12-01
Between 2012 and 2016, the state of California experienced one of the most severe multiyear droughts in nearly 120 years, causing a drastic reduction of freshwater flow to the San Francisco Estuary (SFE). During this period, retention by dams, coupled with the lack of winter rains and spring snow melt led to roughly a third less water reaching the SFE. Decreased freshwater flow to the bay alters the ecology of the SFE, for example by advancing the seasonal timing of phytoplankton blooms, and has been linked to phytoplankton plumes of different, and often more toxic, species. Phytoplankton functional type (PFT) methods, such as PHYDOtax, enable the measurement of community composition, and has been validated in SFE. As part of the NASA Student Airborne Research Program (SARP), we test the accuracy of the PHYDOtax algorithm during the drought period in SFE using matchups between in situ pigment measurements and remotely sensed reflectance spectra from the AVIRIS airborne sensor. We will present time series of salinity and phytoplankton composition in the SFE and evaluate the effects of the drought on the estuarine phytoplankton composition. In the future, California is expected to experience increased frequency of extreme weather events, such as drought, as a consequence of climate change. We evaluate the consequences of the drought on phytoplankton community composition to understand how future extreme weather events may alter the ecology or toxicity of SFE.
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García Molinos, Jorge; Takao, Shintaro; Kumagai, Naoki H; Poloczanska, Elvira S; Burrows, Michael T; Fujii, Masahiko; Yamano, Hiroya
2017-10-01
Conservation efforts strive to protect significant swaths of terrestrial, freshwater and marine ecosystems from a range of threats. As climate change becomes an increasing concern, these efforts must take into account how resilient-protected spaces will be in the face of future drivers of change such as warming temperatures. Climate landscape metrics, which signal the spatial magnitude and direction of climate change, support a convenient initial assessment of potential threats to and opportunities within ecosystems to inform conservation and policy efforts where biological data are not available. However, inference of risk from purely physical climatic changes is difficult unless set in a meaningful ecological context. Here, we aim to establish this context using historical climatic variability, as a proxy for local adaptation by resident biota, to identify areas where current local climate conditions will remain extant and future regional climate analogues will emerge. This information is then related to the processes governing species' climate-driven range edge dynamics, differentiating changes in local climate conditions as promoters of species range contractions from those in neighbouring locations facilitating range expansions. We applied this approach to assess the future climatic stability and connectivity of Japanese waters and its network of marine protected areas (MPAs). We find 88% of Japanese waters transitioning to climates outside their historical variability bounds by 2035, resulting in large reductions in the amount of available climatic space potentially promoting widespread range contractions and expansions. Areas of high connectivity, where shifting climates converge, are present along sections of the coast facilitated by the strong latitudinal gradient of the Japanese archipelago and its ocean current system. While these areas overlap significantly with areas currently under significant anthropogenic pressures, they also include much of the MPA network that may provide stepping-stone protection for species that must shift their distribution because of climate change. © 2017 John Wiley & Sons Ltd.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Qiu, D.; Tu, Q.; He, Zhili
2010-05-17
Respiratory versatility and psychrophily are the hallmarks of Shewanella. The ability to utilize a wide range of electron acceptors for respiration is due to the large number of c-type cytochrome genes present in the genome of Shewanella strains. More recently the dissimilatory metal reduction of Shewanella species has been extensively and intensively studied for potential applications in the bioremediation of radioactive wastes of groundwater and subsurface environments. Multiple Shewanella genome sequences are now available in the public databases (Fredrickson et al., 2008). Most of the sequenced Shewanella strains were isolated from marine environments and this genus was believed to bemore » of marine origin (Hau and Gralnick, 2007). However, the well-characterized model strain, S. oneidensis MR-1, was isolated from the freshwater lake sediment of Lake Oneida, New York (Myers and Nealson, 1988) and similar bacteria have also been isolated from other freshwater environments (Venkateswaran et al., 1999). Here we comparatively analyzed the genome sequence and physiological characteristics of S. putrefaciens W3-18-1 and S. oneidensis MR-1, isolated from the marine and freshwater lake sediments, respectively. The anaerobic respirations, carbon source utilization, and cell motility have been experimentally investigated. Large scale horizontal gene transfers have been revealed and the genetic divergence between these two strains was considered to be critical to the bacterial adaptation to specific habitats, freshwater or marine sediments.« less
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Zipper, Carl E; Donovan, Patricia F; Jones, Jess W; Li, Jing; Price, Jennifer E; Stewart, Roger E
2016-01-15
The Powell River of southwestern Virginia and northeastern Tennessee, USA, drains a watershed with extensive coal surface mining, and it hosts exceptional biological richness, including at-risk species of freshwater mussels, downstream of mining-disturbed watershed areas. We investigated spatial and temporal patterns of watershed mining disturbance; their relationship to water quality change in the section of the river that connects mining areas to mussel habitat; and relationships of mining-related water constituents to measures of recent and past mussel status. Freshwater mussels in the Powell River have experienced significant declines over the past 3.5 decades. Over that same period, surface coal mining has influenced the watershed. Water-monitoring data collected by state and federal agencies demonstrate that dissolved solids and associated constituents that are commonly influenced by Appalachian mining (specific conductance, pH, hardness and sulfates) have experienced increasing temporal trends from the 1960s through ~2008; but, of those constituents, only dissolved solids concentrations are available widely within the Powell River since ~2008. Dissolved solids concentrations have stabilized in recent years. Dissolved solids, specific conductance, pH, and sulfates also exhibited spatial patterns that are consistent with dilution of mining influence with increasing distance from mined areas. Freshwater mussel status indicators are correlated negatively with dissolved solids concentrations, spatially and temporally, but the direct causal mechanisms responsible for mussel declines remain unknown. Copyright © 2015 Elsevier B.V. All rights reserved.
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Changes in freshwater mussel communities linked to legacy pollution in the Lower Delaware River
Blakeslee, Carrie J.; Silldorff, Erik L.; Galbraith, Heather S.
2018-01-01
Freshwater mussels are among the most-imperiled organisms worldwide, although they provide a variety of important functions in the streams and rivers they inhabit. Among Atlantic-slope rivers, the Delaware River is known for its freshwater mussel diversity and biomass; however, limited data are available on the freshwater mussel fauna in the lower, non-tidal portion of the river. This section of the Delaware River has experienced decades of water-quality degradation from both industrial and municipal sources, primarily as a function of one of its major tributaries, the Lehigh River. We completed semi-quantitative snorkel surveys in 53.5 of the 121 km of the river to document mussel community composition and the continued impacts from pollution (particularly inputs from the Lehigh River) on mussel fauna. We detected changes in mussel catch per unit effort (CPUE) below the confluence of the Lehigh River, with significant declines in the dominant species Elliptio complanata (Eastern Elliptio) as we moved downstream from its confluence—CPUE dropped from 179 to 21 mussels/h. Patterns in mussel distribution around the Lehigh confluence matched chemical signatures of Lehigh water input. Specifically, Eastern Elliptio CPUE declined more quickly moving downstream on the Pennsylvania bank, where Lehigh River water input was more concentrated compared to the New Jersey bank. A definitive causal link remains to be established between the Lehigh River and the dramatic shifts in mussel community composition, warranting continued investigation as it relates to mussel conservation and restoration in the basin.
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Murray, K; Roux, D J; Nel, J L; Driver, A; Freimund, W
2011-05-01
The ability of an organisation to recognise the value of new external information, acquire it, assimilate it, transform, and exploit it, namely its absorptive capacity (AC), has been much researched in the context of commercial organisations and even applied to national innovation. This paper considers four key AC-related concepts and their relevance to public sector organisations with mandates to manage and conserve freshwater ecosystems for the common good. The concepts are the importance of in-house prior related knowledge, the importance of informal knowledge transfer, the need for motivation and intensity of effort, and the importance of gatekeepers. These concepts are used to synthesise guidance for a way forward in respect of such freshwater management and conservation, using the imminent release of a specific scientific conservation planning and management tool in South Africa as a case study. The tool comprises a comprehensive series of maps that depict national freshwater ecosystem priority areas for South Africa. Insights for implementing agencies relate to maintaining an internal science, rather than research capacity; making unpublished and especially tacit knowledge available through informal knowledge transfer; not underestimating the importance of intensity of effort required to create AC, driven by focussed motivation; and the potential use of a gatekeeper at national level (external to the implementing organisations), possibly playing a more general 'bridging' role, and multiple internal (organisational) gatekeepers playing the more limited role of 'knowledge translators'. The role of AC as a unifying framework is also proposed.
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NASA Astrophysics Data System (ADS)
cerda Garcia, C. G.; Carpenter, P. J.; Leal-Bautista, R. M.
2017-12-01
Geophysical surveys were used to determine the depth of the freshwater/saltwater interface and groundwater preferential flow pathways along the Ruta de los Cenotes, near Puerto Morelos (northeast part of the Yucatán peninsula). The Yucatán Peninsula is a limestone platform that allows quick recharge of the aquifer, the main supply of water for this region. The water in the aquifer is divided into freshwater and saltwater zones. A Schlumberger resistivity sounding along the road near one cenote suggests the water table is 5 meters deep and the freshwater/saltwater interface is 38 meters deep. A time-domain electromagnetic (TEM) sounding suggests the freshwater/saltwater interface is 45 meters deep. The depth of the interface determines the volume of fresh water available. Preferential flow pathways in the vadose and saturated zones are karst conduits where groundwater percolates downward in the vadose zone. These were identified using resistivity profiling and spontaneous self-potential (SP) geophysical methods. Interpretation of SP profile Line SP1, located 3 m south of the cenote, suggests two fractures, which appear to extend south as far as SP profile Line SP2, 15 m south of the cenote; both lines are parallel to each other. SP anomalies suggest water flow along these fractures. The use of noninvasive geophysical methods, specifically SP, resistivity and TEM are useful for exploring the karst system in the Yucatán peninsula.
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Freshwater flow from estuarine creeks into northeastern Florida Bay
Hittle, Clinton; Patino, Eduardo; Zucker, Mark A.
2001-01-01
Water-level, water-velocity, salinity, and temperature data were collected from selected estuarine creeks to compute freshwater flow into northeastern Florida Bay. Calibrated equations for determining mean velocity from acoustic velocity were obtained by developing velocity relations based on direct acoustic measurements, acoustic line velocity, and water level. Three formulas were necessary to describe flow patterns for all monitoring sites, with R2 (coefficient of determination) values ranging from 0.957 to 0.995. Cross-sectional area calculations were limited to the main channel of the creeks and did not include potential areas of overbank flow. Techniques also were used to estimate discharge at noninstrumented sites by establishing discharge relations to nearby instrumented sites. Results of the relation between flows at instrumented and noninstrumented sites varied with R2 values ranging from 0.865 to 0.99. West Highway Creek was used to estimate noninstrumented sites in Long Sound, and Mud Creek was used to estimate East Creek in Little Madeira Bay. Mean monthly flows were used to describe flow patterns and to calculate net flow along the northeastern coastline. Data used in the study were collected from October 1995 through September 1999, which includes the El Nino event of 1998. During this period, about 80 percent of the freshwater flowing into the bay occurred during the wet season (May-October). The mean freshwater discharge for all five instrumented sites during the wet season from 1996 to 1999 is 106 cubic feet per second. The El Nino event caused a substantial increase (654 percent) in mean flows during the dry season (November-April) at the instrumented sites, ranging from 8.5 cubic feet per second in 1996-97 to 55.6 cubic feet per second in 1997-98. Three main flow signatures were identified when comparing flows at all monitoring stations. The most significant was the magnitude of discharges at Trout Creek, which carries about 50 percent of the total measured freshwater entering northeastern Florida Bay. The mean monthly wet-season (May-October) flow at Trout Creek is about 340 cubic feet per second, compared to 55 cubic feet per second at West Highway Creek, 52 cubic feet per second at Taylor River, 49 cubic feet per second at Mud Creek, and 33 cubic feet per second at McCormick Creek. The other two flow signatures are the decline of freshwater discharge at McCormick Creek at the start of the El Nino event, and the absence of net-negative flows at West Highway Creek. The observed flow distribution within the study area, suggests that the overall flow direction of freshwater in the Everglades wetlands in the lower part of Taylor Slough may have a strong eastward flow component as water approaches the coastline. Data analysis also indicates that Trout Creek could potentially be used as a long-term monitoring station to estimate total freshwater flow into northeastern Florida Bay, provided that the remaining questions regarding flow patterns at McCormick Creek and the creeks in Long Sound are answered and that no major changes in flow characteristics occur in the future.
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Paerl, Hans
2008-01-01
Nutrient and hydrologic conditions strongly influence harmful planktonic and benthic cyanobacterial bloom (CHAB) dynamics in aquatic ecosystems ranging from streams and lakes to coastal ecosystems. Urbanization, agricultural and industrial development have led to increased nitrogen (N) and phosphorus (P) discharge, which affect CHAB potentials of receiving waters. The amounts, proportions and chemical composition of N and P sources can influence the composition, magnitude and duration of blooms. This, in turn, has ramifications for food web dynamics (toxic or inedible CHABs), nutrient and oxygen cycling and nutrient budgets. Some CHABs are capable of N2 fixation, a process that can influence N availability and budgets. Certain invasive N2 fixing taxa (e.g., Cylindrospermopsis, Lyngbya) also effectively compete for fixed N during spring, N-enriched runoff periods, while they use N2 fixation to supplant their N needs during N-deplete summer months. Control of these taxa is strongly dependent on P supply. However, additional factors, such as molar N:P supply ratios, organic matter availability, light attenuation, freshwater discharge, flushing rates (residence time) and water column stability play interactive roles in determining CHAB composition (i.e. N2 fixing vs. non-N2 fixing taxa) and biomass. Bloom potentials of nutrient-impacted waters are sensitive to water residence (or flushing) time, temperatures (preference for > 15 degrees C), vertical mixing and turbidity. These physical forcing features can control absolute growth rates of bloom taxa. Human activities may affect "bottom up" physical-chemical modulators either directly, by controlling hydrologic, nutrient, sediment and toxic discharges, or indirectly, by influencing climate. Control and management of cyanobacterial and other phytoplankton blooms invariably includes nutrient input constraints, most often focused on N and/or P. While single nutrient input constraints may be effective in some water bodies, dual N and P input reductions are usually required for effective long-term control and management of blooms. In some systems where hydrologic manipulations (i.e., plentiful water supplies) are possible, reducing the water residence time by flushing and artificial mixing (along with nutrient input constraints) can be effective alternatives. Blooms that are not readily consumed and transferred up the food web will form a relatively large proportion of sedimented organic matter. This, in turn, will exacerbate sediment oxygen demand, and enhance the potential for oxygen depletion and release of nutrients back to the water column. This scenario is particularly problematic in long-residence time (i.e., months) systems, where blooms may exert a strong positive feedback on future events. Implications of these scenarios and the confounding issues of climatic (hydrologic) variability, including droughts, tropical storms, hurricanes and floods, will be discussed in the context of developing effective CHAB control strategies along the freshwater-marine continuum.
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Great Lakes ecosystems are generally thought to be P-limited, but N-limitation may be more common than previously suspected. N-limitation should be most obvious in freshwater coastal wetlands, where the anaerobic oxidation of organic carbon may be limited by nitrate availability...
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Complexation by dissolved humic substances has an important influence on
trace metal behavior in natural systems. Unfortunately, few analytical
techniques are available with adequate sensitivity and selectivity to measure
free metal ions reliably at the low concent...