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1

Columbia River Plume andColumbia River Plume and California Current Ecosystem:California Current Ecosystem  

E-print Network

Columbia River Plume andColumbia River Plume and California Current Ecosystem:California Current Ecosystem: Role in Salmon ProductivityRole in Salmon Productivity NOAA FisheriesNOAA Fisheries Northwest conditions/survivalfreshwater conditions/survival ·· The coastal pelagic ecosystem is dynamic andThe coastal

2

Modeling observed California Current mesoscale eddies and the ecosystem response  

Microsoft Academic Search

Satellite and in situ observations are used to test model dynamics for the California Current System (CCS). The model and data are combined to reconstruct the mesoscale ocean structure during a given three-week period. The resulting physical flow field is used to drive a 3D ecosystem model to interpret SeaWiFS and in situ chlorophyll-a (Chl -a) variations. With this approach

E. Di Lorenzo; A. J. Miller; D. J. Neilson; B. D. Cornuelle; J. R. Moisan

3

Modelling observed California Current mesoscale eddies and the ecosystem response  

Microsoft Academic Search

Satellite and in situ observations are used to test model dynamics for the California Current System (CCS). The model and data are combined to reconstruct the mesoscale ocean structure during a given three-week period. The resulting physical flow field is used to drive a 3D ecosystem model to interpret SeaWiFS and in situ chlorophyll-a (chl-a) variations. With this approach a

Emanuele di Lorenzo; Douglas Neilson; Bruce Cornuelle; John Moisan; Arthur Miller

2004-01-01

4

Climate impacts on the planktonic marine ecosystem in the Southern California current  

E-print Network

funding from DOE (DE-FG02- 04ER63857), ONR (N00014-05-1-0363), NASA (funding from NSF through the California Current Ecosystem LTER (OCE-0417616), NASA (funding from DOE (DE-FG02-04ER63857), ONR (N00014-05-1-0363), NASA (

Kim, Hey-Jin

2008-01-01

5

Exploring local adaptation and the ocean acidification seascape - studies in the California Current Large Marine Ecosystem  

NASA Astrophysics Data System (ADS)

The California Current Large Marine Ecosystem (CCLME), a temperate marine region dominated by episodic upwelling, is predicted to experience rapid environmental change in the future due to ocean acidification. Aragonite saturation state within the California Current System is predicted to decrease in the future, with near-permanent undersaturation conditions expected by the year 2050. Thus, the CCLME is a critical region to study due to the rapid rate of environmental change that resident organisms will experience and because of the economic and societal value of this coastal region. Recent efforts by a research consortium - the Ocean Margin Ecosystems Group for Acidification Studies (OMEGAS) - has begun to characterize a portion of the CCLME; both describing the mosaic of pH in coastal waters and examining the responses of key calcification-dependent benthic marine organisms to natural variation in pH and to changes in carbonate chemistry that are expected in the coming decades. In this review, we present the OMEGAS strategy of co-locating sensors and oceanographic observations with biological studies on benthic marine invertebrates, specifically measurements of functional traits such as calcification-related processes and genetic variation in populations that are locally adapted to conditions in a particular region of the coast. Highlighted in this contribution are (1) the OMEGAS sensor network that spans the west coast of the US from central Oregon to southern California, (2) initial findings of the carbonate chemistry amongst the OMEGAS study sites, (3) an overview of the biological data that describes the acclimatization and the adaptation capacity of key benthic marine invertebrates within the CCLME.

Hofmann, G. E.; Evans, T. G.; Kelly, M. W.; Padilla-Gamiño, J. L.; Blanchette, C. A.; Washburn, L.; Chan, F.; McManus, M. A.; Menge, B. A.; Gaylord, B.; Hill, T. M.; Sanford, E.; LaVigne, M.; Rose, J. M.; Kapsenberg, L.; Dutton, J. M.

2013-07-01

6

Exploring local adaptation and the ocean acidification seascape - studies in the California Current Large Marine Ecosystem  

NASA Astrophysics Data System (ADS)

The California Current Large Marine Ecosystem (CCLME), a temperate marine region dominated by episodic upwelling, is predicted to experience rapid environmental change in the future due to ocean acidification. The aragonite saturation state within the California Current System is predicted to decrease in the future with near-permanent undersaturation conditions expected by the year 2050. Thus, the CCLME is a critical region to study due to the rapid rate of environmental change that resident organisms will experience and because of the economic and societal value of this coastal region. Recent efforts by a research consortium - the Ocean Margin Ecosystems Group for Acidification Studies (OMEGAS) - has begun to characterize a portion of the CCLME; both describing the spatial mosaic of pH in coastal waters and examining the responses of key calcification-dependent benthic marine organisms to natural variation in pH and to changes in carbonate chemistry that are expected in the coming decades. In this review, we present the OMEGAS strategy of co-locating sensors and oceanographic observations with biological studies on benthic marine invertebrates, specifically measurements of functional traits such as calcification-related processes and genetic variation in populations that are locally adapted to conditions in a particular region of the coast. Highlighted in this contribution are (1) the OMEGAS sensor network that spans the west coast of the US from central Oregon to southern California, (2) initial findings of the carbonate chemistry amongst the OMEGAS study sites, and (3) an overview of the biological data that describes the acclimatization and the adaptation capacity of key benthic marine invertebrates within the CCLME.

Hofmann, G. E.; Evans, T. G.; Kelly, M. W.; Padilla-Gamiño, J. L.; Blanchette, C. A.; Washburn, L.; Chan, F.; McManus, M. A.; Menge, B. A.; Gaylord, B.; Hill, T. M.; Sanford, E.; LaVigne, M.; Rose, J. M.; Kapsenberg, L.; Dutton, J. M.

2014-02-01

7

Screening California Current fishery management scenarios using the Atlantis end-to-end ecosystem model  

NASA Astrophysics Data System (ADS)

End-to-end marine ecosystem models link climate and oceanography to the food web and human activities. These models can be used as forecasting tools, to strategically evaluate management options and to support ecosystem-based management. Here we report the results of such forecasts in the California Current, using an Atlantis end-to-end model. We worked collaboratively with fishery managers at NOAA’s regional offices and staff at the National Marine Sanctuaries (NMS) to explore the impact of fishery policies on management objectives at different spatial scales, from single Marine Sanctuaries to the entire Northern California Current. In addition to examining Status Quo management, we explored the consequences of several gear switching and spatial management scenarios. Of the scenarios that involved large scale management changes, no single scenario maximized all performance metrics. Any policy choice would involve trade-offs between stakeholder groups and policy goals. For example, a coast-wide 25% gear shift from trawl to pot or longline appeared to be one possible compromise between an increase in spatial management (which sacrificed revenue) and scenarios such as the one consolidating bottom impacts to deeper areas (which did not perform substantially differently from Status Quo). Judged on a coast-wide scale, most of the scenarios that involved minor or local management changes (e.g. within Monterey Bay NMS only) yielded results similar to Status Quo. When impacts did occur in these cases, they often involved local interactions that were difficult to predict a priori based solely on fishing patterns. However, judged on the local scale, deviation from Status Quo did emerge, particularly for metrics related to stationary species or variables (i.e. habitat and local metrics of landed value or bycatch). We also found that isolated management actions within Monterey Bay NMS would cause local fishers to pay a cost for conservation, in terms of reductions in landed value. However, this cost was minimal when local conservation actions were part of a concerted coast-wide plan. The simulations demonstrate the utility of using the Atlantis end-to-end ecosystem model within NOAA’s Integrated Ecosystem Assessment, by illustrating an end-to-end modeling tool that allows consideration of multiple management alternatives that are relevant to numerous state, federal and private interests.

Kaplan, Isaac C.; Horne, Peter J.; Levin, Phillip S.

2012-09-01

8

Enhanced nutrient supply to the California Current Ecosystem with global warming and increased stratification in an earth system model  

Microsoft Academic Search

A leading hypothesis relating productivity with climate variability in the California Current Ecosystem (CCE) describes an alternation between warmer, well-stratified periods of low productivity and cooler periods of high productivity. This empirical relationship suggests that productivity will decline with global warming. Here, we explore the response of productivity to future climate change in the CCE using an earth system model.

Ryan R. Rykaczewski; John P. Dunne

2010-01-01

9

Declining Abundance of Beaked Whales (Family Ziphiidae) in the California Current Large Marine Ecosystem  

PubMed Central

Beaked whales are among the most diverse yet least understood groups of marine mammals. A diverse set of mostly anthropogenic threats necessitates improvement in our ability to assess population status for this cryptic group. The Southwest Fisheries Science Center (NOAA) conducted six ship line-transect cetacean abundance surveys in the California Current off the contiguous western United States between 1991 and 2008. We used a Bayesian hidden-process modeling approach to estimate abundance and population trends of beaked whales using sightings data from these surveys. We also compiled records of beaked whale stranding events (3 genera, at least 8 species) on adjacent beaches from 1900 to 2012, to help assess population status of beaked whales in the northern part of the California Current. Bayesian posterior summaries for trend parameters provide strong evidence of declining beaked whale abundance in the study area. The probability of negative trend for Cuvier's beaked whale (Ziphius cavirostris) during 1991–2008 was 0.84, with 1991 and 2008 estimates of 10771 (CV?=?0.51) and ?7550 (CV?=?0.55), respectively. The probability of decline for Mesoplodon spp. (pooled across species) was 0.96, with 1991 and 2008 estimates of 2206 (CV?=?0.46) and 811 (CV?=?0.65). The mean posterior estimates for average rate of decline were 2.9% and 7.0% per year. There was no evidence of abundance trend for Baird's beaked whale (Berardius bairdii), for which annual abundance estimates in the survey area ranged from ?900 to 1300 (CV?1.3). Stranding data were consistent with the survey results. Causes of apparent declines are unknown. Direct impacts of fisheries (bycatch) can be ruled out, but impacts of anthropogenic sound (e.g., naval active sonar) and ecosystem change are plausible hypotheses that merit investigation. PMID:23341907

Moore, Jeffrey E.; Barlow, Jay P.

2013-01-01

10

El Niño and similar perturbation effects on the benthos of the Humboldt, California, and Benguela Current upwelling ecosystems  

NASA Astrophysics Data System (ADS)

To a certain degree, Eastern Boundary Current (EBC) ecosystems are similar: Cold bottom water from moderate depths, rich in nutrients, is transported to the euphotic zone by a combination of trade winds, Coriolis force and Ekman transport. The resultant high primary production fuels a rich secondary production in the upper pelagic and nearshore zones, but where O2 exchange is restricted, it creates oxygen minimum zones (OMZs) at shelf and upper slope (Humboldt and Benguela Current) or slope depths (California Current). These hypoxic zones host a specifically adapted, small macro- and meiofauna together with giant sulphur bacteria that use nitrate to oxydise H2S. In all EBC, small polychaetes, large nematodes and other opportunistic benthic species have adapted to the hypoxic conditions and co-exist with sulphur bacteria, which seem to be particularly dominant off Peru and Chile. However, a massive reduction of macrobenthos occurs in the core of the OMZ. In the Humboldt Current area the OMZ ranges between <100 and about 600 m, with decreasing thickness in a poleward direction. The OMZ merges into better oxygenated zones towards the deep sea, where large cold-water mega- and macrofauna occupy a dominant role as in the nearshore strip. The Benguela Current OMZ has a similar upper limit but remains shallower. It also hosts giant sulphur bacteria but little is known about the benthic fauna. However, sulphur eruptions and intense hypoxia might preclude the coexistence of significant mega- und macrobenthos. Conversely, off North America the upper limit of the OMZ is considerably deeper (e.g., 500-600 m off California and Oregon), and the lower boundary may exceed 1000m. The properties described are valid for very cold and cold (La Niña and "normal") ENSO conditions with effective upwelling of nutrient-rich bottom water. During warm (El Niño) episodes, warm water masses of low oxygen concentration from oceanic and equatorial regions enter the upwelling zones, bringing a variety of (sub)tropical immigrants. The autochthonous benthic fauna emigrates to deeper water or poleward, or suffers mortality. However, some local macrofaunal species experience important population proliferations, presumably due to improved oxygenation (in the southern hemisphere), higher temperature tolerance, reduced competition or the capability to use different food. Both these negative and positive effects of El Niño influence local artisanal fisheries and the livelihood of coastal populations. In the Humboldt Current system the hypoxic seafloor at outer shelf depths receives important flushing from the equatorial zone, causing havoc on the sulphur bacteria mats and immediate recolonisation of the sediments by mega- and macrofauna. Conversely, off California, the intruding equatorial water masses appear to have lower oxygen than ambient waters, and may cause oxygen deficiency at upper slope depths. Effects of this change have not been studied in detail, although shrimp and other taxa appear to alter their distribution on the continental margin. Other properties and reactions of the two Pacific EBC benthic ecosystems to El Niño seem to differ, too, as does the overall impact of major episodes (e.g., 1982/1983(1984) vs. 1997/1998). The relation of the "Benguela Niño" to ENSO seems unclear although many Pacific-Atlantic ocean and atmosphere teleconnections have been described. Warm, low-oxygen equatorial water seems to be transported into the upwelling area by similar mechanisms as in the Pacific, but most major impacts on the eukaryotic biota obviously come from other, independent perturbations such as an extreme eutrophication of the sediments ensuing in sulphidic eruptions and toxic algal blooms. Similarities and differences of the Humboldt and California Current benthic ecosystems are discussed with particular reference to ENSO impacts since 1972/73. Where there are data available, the authors include the Benguela Current ecosystem as another important, non-Pacific EBC, which also suffers from the effects of hypoxia.

Arntz, W. E.; Gallardo, V. A.; Gutiérrez, D.; Isla, E.; Levin, L. A.; Mendo, J.; Neira, C.; Rowe, G. T.; Tarazona, J.; Wolff, M.

2006-03-01

11

Do inverse ecosystem models accurately reconstruct plankton trophic flows? Comparing two solution methods using field data from the California Current  

NASA Astrophysics Data System (ADS)

Despite the increasing use of linear inverse modeling techniques to elucidate fluxes in undersampled marine ecosystems, the accuracy with which they estimate food web flows has not been resolved. New Markov Chain Monte Carlo (MCMC) solution methods have also called into question the biases of the commonly used L2 minimum norm (L 2MN) solution technique. Here, we test the abilities of MCMC and L 2MN methods to recover field-measured ecosystem rates that are sequentially excluded from the model input. For data, we use experimental measurements from process cruises of the California Current Ecosystem (CCE-LTER) Program that include rate estimates of phytoplankton and bacterial production, micro- and mesozooplankton grazing, and carbon export from eight study sites varying from rich coastal upwelling to offshore oligotrophic conditions. Both the MCMC and L 2MN methods predicted well-constrained rates of protozoan and mesozooplankton grazing with reasonable accuracy, but the MCMC method overestimated primary production. The MCMC method more accurately predicted the poorly constrained rate of vertical carbon export than the L 2MN method, which consistently overestimated export. Results involving DOC and bacterial production were equivocal. Overall, when primary production is provided as model input, the MCMC method gives a robust depiction of ecosystem processes. Uncertainty in inverse ecosystem models is large and arises primarily from solution under-determinacy. We thus suggest that experimental programs focusing on food web fluxes expand the range of experimental measurements to include the nature and fate of detrital pools, which play large roles in the model.

Stukel, Michael R.; Landry, Michael R.; Ohman, Mark D.; Goericke, Ralf; Samo, Ty; Benitez-Nelson, Claudia R.

2012-03-01

12

North Pacific Gyre Oscillation modulates seasonal timing and ecosystem functioning in the California Current  

E-print Network

a significant fraction of interannual to decadal salinity, nutri- ent and chlorophyll-a (Chl-a) variance off ecosystem throughout spring and summer, i.e., several months after the direct NPGO effects on the system of the ocean-atmosphere system can be characterized by different modes of variabil- ity. A mode of variability

Boyer, Edmond

13

Variability in diatom contributions to biomass, organic matter production and export across a frontal gradient in the California Current Ecosystem  

NASA Astrophysics Data System (ADS)

In the offshore waters of Southern California, submesoscale processes associated with fronts may stimulate phytoplankton blooms and lead to biomass shifts at multiple trophic levels. Here we report the results of a study on the cycling of biogenic silica (bSiO2) with estimates of the contributions of diatoms to primary and new production in water masses adjacent to (i.e., coastal or oceanic) and within an offshore front in the Southern California Current Ecosystem (CCE). The coastal and oceanic water were sampled in cyclonic and anticyclonic eddies, respectively, with the frontal water being an interaction region between the eddy types. Concentrations of bSiO2 varied by 25-fold across the front, with concentrations in frontal waters 20-25% of those in coastal waters. Rates of biogenic silica production spanned an equally large range, with rates within the frontal region that were half those in the coastal regions. Contributions of diatoms to primary and new production were disproportionately higher than their contribution to autotrophic biomass in all areas, ranging from 5-8%, 19-30%, and 32-43% for both processes in the oceanic, frontal and coastal waters, respectively. Across the frontal area, diatoms could account for <1.0%, 6-8%, and 44-72% of organic matter export in the oceanic, frontal and coastal waters, respectively. The results suggest that the regions of frontal interactions between eddies in the southern CCE can account for variability in diatom biomass, productivity and export over very short spatial scales that is comparable to the variability observed across the Pacific basin.

Krause, Jeffrey W.; Brzezinski, Mark A.; Goericke, Ralf; Landry, Michael R.; Ohman, Mark D.; Stukel, Michael R.; Taylor, Andrew G.

2015-02-01

14

Signs of adaptation to local pH conditions across an environmental mosaic in the California Current Ecosystem.  

PubMed

Little is known about the potential for rapid evolution in natural populations in response to the high rate of contemporary climatic change. Organisms that have evolved in environments that experience high variability across space and time are of particular interest as they may harbor genetic variation that can facilitate evolutionary response to changing conditions. Here we review what is known about genetic capacity for adaptation in the purple sea urchin, Strongylocentrotus purpuratus, a species that has evolved in the upwelling ecosystem of the Northeast Pacific Ocean. We also present new results testing for adaptation to local pH conditions in six populations from Oregon to southern California. We integrate data on 19,493 genetic polymorphisms with data on local pH conditions. We find correlations between allele frequency and rank average time spent at pH <7.8 in 318 single-nucleotide polymorphisms in 275 genes. Two of the genes most correlated with local pH are a protein associated with the cytoskeleton and a proton pump, with functional roles in maintenance of cell volume and with internal regulation of pH, respectively. Across all loci tested, high correlations with local pH were concentrated in genes related to transport of ions, biomineralization, lipid metabolism, and cell-cell adhesion, functional pathways important for maintaining homeostasis at low pH. We identify a set of seven genes as top candidates for rapid evolutionary response to acidification of the ocean. In these genes, the putative low-pH-adapted allele, based on allele frequencies in natural populations, rapidly increases in frequency in purple sea urchin larvae raised at low pH. We also found that populations from localities with high pH show a greater change in allele frequency toward putative low-pH-adapted alleles under experimental acidification, compared with low-pH populations, suggesting that both natural and artificial selection favor the same alleles for response to low pH. These results illustrate that purple sea urchins may be adapted to local pH and suggest that this species may possess the genetic capacity for rapid evolution in response to acidification. This adaptive capacity likely comes from standing genetic variation maintained in nature by balancing selection across the spatial and temporal environmental mosaic that characterizes the California Current Ecosystem. PMID:23980118

Pespeni, M H; Chan, F; Menge, B A; Palumbi, S R

2013-11-01

15

Delta Revival: Restoring a California Ecosystem  

USGS Publications Warehouse

'Delta Revival: Restoring a California Ecosystem' shows scientists from many disciplines working together to guide the unprecendented restoration of the Sacramento- San Joaquin Delta east of San Francisco Bay.

U.S. Geological Survey; California Bay Delta Authority

2003-01-01

16

Ekstrom, Draft 11/14/08 California Current Large Marine Ecosystem: Publicly Available Dataset of State and  

E-print Network

], it is reasonable to begin with the laws and regulations that are used to guide and regulate ocean and coastal Dataset of State and Federal Laws and Regulations Julia A. Ekstrom Affiliation (at time work was performed, ocean law, large marine ecosystem INTRODUCTION Historically, governments have managed ocean uses within

Stanford University

17

Mapping Groundwater Dependent Ecosystems in California  

PubMed Central

Background Most groundwater conservation and management efforts focus on protecting groundwater for drinking water and for other human uses with little understanding or focus on the ecosystems that depend on groundwater. However, groundwater plays an integral role in sustaining certain types of aquatic, terrestrial and coastal ecosystems, and their associated landscapes. Our aim was to illuminate the connection between groundwater and surface ecosystems by identifying and mapping the distribution of groundwater dependent ecosystems (GDEs) in California. Methodology/Principal Findings To locate where groundwater flow sustains ecosystems we identified and mapped groundwater dependent ecosystems using a GIS. We developed an index of groundwater dependency by analyzing geospatial data for three ecosystem types that depend on groundwater: (1) springs and seeps; (2) wetlands and associated vegetation alliances; and (3) stream discharge from groundwater sources (baseflow index). Each variable was summarized at the scale of a small watershed (Hydrologic Unit Code-12; mean size?=?9,570 ha; n?=?4,621), and then stratified and summarized to 10 regions of relative homogeneity in terms of hydrologic, ecologic and climatic conditions. We found that groundwater dependent ecosystems are widely, although unevenly, distributed across California. Although different types of GDEs are clustered more densely in certain areas of the state, watersheds with multiple types of GDEs are found in both humid (e.g. coastal) and more arid regions. Springs are most densely concentrated in the North Coast and North Lahontan, whereas groundwater dependent wetlands and associated vegetation alliances are concentrated in the North and South Lahontan and Sacramento River hydrologic regions. The percentage of land area where stream discharge is most dependent on groundwater is found in the North Coast, Sacramento River and Tulare Lake regions. GDE clusters are located at the highest percentage in the North Coast (an area of the highest annual rainfall totals), North Lahontan (an arid, high desert climate with low annual rainfall), and Sacramento River hydrologic regions. That GDEs occur in such distinct climatic and hydrologic settings reveals the widespread distribution of these ecosystems. Conclusions/Significance Protection and management of groundwater-dependent ecosystems are hindered by lack of information on their diversity, abundance and location. By developing a methodology that uses existing datasets to locate GDEs, this assessment addresses that knowledge gap. We report here on the application of this method across California, but believe the method can be expanded to regions where spatial data exist. PMID:20585640

Howard, Jeanette; Merrifield, Matt

2010-01-01

18

The Development of Automated Detection Techniques for Passive Acoustic Monitoring as a Tool for Studying Beaked Whale Distribution and Habitat Preferences in the California Current Ecosystem  

NASA Astrophysics Data System (ADS)

The objectives of this research were to test available automated detection methods for passive acoustic monitoring and integrate the best available method into standard marine mammal monitoring protocols for ship based surveys. The goal of the first chapter was to evaluate the performance and utility of PAMGUARD 1.0 Core software for use in automated detection of marine mammal acoustic signals during towed array surveys. Three different detector configurations of PAMGUARD were compared. These automated detection algorithms were evaluated by comparing them to the results of manual detections made by an experienced bio-acoustician (author TMY). This study provides the first detailed comparisons of PAMGUARD automated detection algorithms to manual detection methods. The results of these comparisons clearly illustrate the utility of automated detection methods for odontocete species. Results of this work showed that the majority of whistles and click events can be reliably detected using PAMGUARD software. The second chapter moves beyond automated detection to examine and test automated classification algorithms for beaked whale species. Beaked whales are notoriously elusive and difficult to study, especially using visual survey methods. The purpose of the second chapter was to test, validate, and compare algorithms for detection of beaked whales in acoustic line-transect survey data. Using data collected at sea from the PAMGUARD classifier developed in Chapter 2 it was possible to measure the clicks from visually verified Baird's beaked whale encounters and use this data to develop classifiers that could discriminate Baird's beaked whales from other beaked whale species in future work. Echolocation clicks from Baird's beaked whales, Berardius bairdii, were recorded during combined visual and acoustic shipboard surveys of cetacean populations in the California Current Ecosystem (CCE) and with autonomous, long-term recorders at four different sites in the Southern California Bight (SCB). The preliminary measurement of the visually validated Baird's beaked whale echolocation signals recorded from the ship-based towed array were used as a basis for identifying Baird's signals in the seafloor-mounted autonomous recorder data. The passive acoustic detection algorithms for beaked whales developed using data from Chapters 2 and 3 were field tested during a three year period to test the reliability of acoustic beaked whale monitoring techniques and to use these methods to describe beaked whale habitat in the SCB. In 2009 and 2010, PAM methods using towed hydrophone arrays were tested. These methods proved highly effective for real-time detection of beaked whales in the SCB and were subsequently implemented in 2011 to successfully detect and track beaked whales during the ongoing Southern California Behavioral Response Study (SOCAL-BRS). The final step in this research was to utilize the passive acoustic detection techniques developed herin to predictively model beaked whale habitat use and preferences in the CCE. This chapter uses a multifaceted approach to model beaked whale encounter rates in the CCE. Beaked whale acoustic encounters are utilized to inform Generalized Additive Models (GAMs) of encounter rate for beaked whales in the CCE and compare these to visual based models. Acoustic and visual based models were independently developed for a small beaked whale group and Baird's beaked whales. Two models were evaluated for visual and acoustic encounters, one that also included Beaufort sea state as a predictor variable in addition to those listed and one that did not include Beaufort sea state. (Abstract shortened by UMI.)

Yack, Tina M.

19

California Water Policy Seminar Series Reconciling Ecosystem And Economy  

E-print Network

California Water Policy Seminar Series Reconciling Ecosystem And Economy Winter 2014 Mondays, 4 Applying reconciliation ecology to aquatic ecosystems in California. Peter Moyle and Melanie Truan, UC of Chief Counsel, State Water Resources Control Board Feb. 10 Reconciling ecosystem goals for San Francisco

Ferrara, Katherine W.

20

Regime shifts in the Humboldt Current ecosystem  

Microsoft Academic Search

Of the four major eastern boundary currents, the Humboldt Current (HC) stands out because it is extremely productive, dominated by anchovy dynamics and subject to frequent direct environmental perturbations of the El Niño Southern Oscillation (ENSO). The long-term dynamics of the HC ecosystem are controlled by shifts between alternating anchovy and sardine regimes that restructure the entire ecosystem from phytoplankton

Jürgen Alheit; Miguel Niquen

2004-01-01

21

Taxonomic Distinctness of Demersal Fishes of the California Current: Moving Beyond Simple Measures of Diversity for Marine Ecosystem-Based Management  

PubMed Central

Background Large-scale patterns or trends in species diversity have long interested ecologists. The classic pattern is for diversity (e.g., species richness) to decrease with increasing latitude. Taxonomic distinctness is a diversity measure based on the relatedness of the species within a sample. Here we examined patterns of taxonomic distinctness in relation to latitude (ca. 32–48 °N) and depth (ca. 50–1220 m) for demersal fishes on the continental shelf and slope of the US Pacific coast. Methodology/Principal Findings Both average taxonomic distinctness (AvTD) and variation in taxonomic distinctness (VarTD) changed with latitude and depth. AvTD was highest at approximately 500 m and lowest at around 200 m bottom depth. Latitudinal trends in AvTD were somewhat weaker and were depth-specific. AvTD increased with latitude on the shelf (50–150 m) but tended to decrease with latitude at deeper depths. Variation in taxonomic distinctness (VarTD) was highest around 300 m. As with AvTD, latitudinal trends in VarTD were depth-specific. On the shelf (50–150 m), VarTD increased with latitude, while in deeper areas the patterns were more complex. Closer inspection of the data showed that the number and distribution of species within the class Chondrichthyes were the primary drivers of the overall patterns seen in AvTD and VarTD, while the relatedness and distribution of species in the order Scorpaeniformes appeared to cause the relatively low observed values of AvTD at around 200 m. Conclusions/Significance These trends contrast to some extent the patterns seen in earlier studies for species richness and evenness in demersal fishes along this coast and add to our understanding of diversity of the demersal fishes of the California Current. PMID:20498727

Tolimieri, Nick; Anderson, Marti J.

2010-01-01

22

Predictability of the California Current System  

NASA Technical Reports Server (NTRS)

The physical and biological oceanography of the Southern California Bight (SCB), a highly productive subregion of the California Current System (CCS) that extends from Point Conception, California, south to Ensenada, Mexico, continues to be extensively studied. For example, the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program has sampled this region for over 50 years, providing an unparalleled time series of physical and biological data. However, our understanding of what physical processes control the large-scale and mesoscale variations in these properties is incomplete. In particular, the non-synoptic and relatively coarse spatial sampling (70km) of the hydrographic grid does not completely resolve the mesoscale eddy field (Figure 1a). Moreover, these unresolved physical variations exert a dominant influence on the evolution of the ecosystem. In recent years, additional datasets that partially sample the SCB have become available. Acoustic Doppler Current Profiler (ADCP) measurements, which now sample upper-ocean velocity between stations, and sea level observations along TOPEX tracks give a more complete picture of the mesoscale variability. However, both TOPEX and ADCP are well-sampled only along the cruise or orbit tracks and coarsely sampled in time and between tracks. Surface Lagrangian drifters also sample the region, although irregularly in time and space. SeaWiFS provides estimates of upper-ocean chlorophyll-a (chl-alpha), usually giving nearly complete coverage for week-long intervals, depending on cloud coverage. Historical ocean color data from the Coastal Zone Color Scanner (CZCS) has been used extensively to determine phytoplankton patterns and variability, characterize the primary production across the SCB coastal fronts, and describe the seasonal and interannual variability in pigment concentrations. As in CalCOFI, these studies described much of the observed structures and their variability over relatively large space and time scales.

Miller, Arthur J.; Chereskin, T.; Cornuelle, B. D.; Niiler, P. P.; Moisan, J. R.; Lindstrom, Eric (Technical Monitor)

2001-01-01

23

Assessment of Potential Aquatic Herbicide Impacts to California Aquatic Ecosystems  

E-print Network

Assessment of Potential Aquatic Herbicide Impacts to California Aquatic Ecosystems Geoffrey S and implement a 3-year monitoring program to determine the potential environmental impacts of aquatic herbicide association with herbicide appli- cations. Applications of acrolein, copper sulfate, chelated copper, diquat

24

Avian Conservation Practices Strengthen Ecosystem Services in California Vineyards  

Microsoft Academic Search

Insectivorous Western Bluebirds (Sialia mexicana) occupy vineyard nest boxes established by California winegrape growers who want to encourage avian conservation. Experimentally, the provision of available nest sites serves as an alternative to exclosure methods for isolating the potential ecosystem services provided by foraging birds. We compared the abundance and species richness of avian foragers and removal rates of sentinel prey

Julie A. Jedlicka; Russell Greenberg; Deborah K. Letourneau

2011-01-01

25

Integrated Ecosystem Assessment of the California Current  

E-print Network

;i Edited by Phillip S. Levin1 , Brian K. Wells2 , and Mindi B. Sheer1 From contributions , Marlene A. Bellman1 , Steven J. Bograd2 , Richard D. Brodeur1 , Christopher J. Brown, Susan J. Chivers2 Peterson1 , Mark L. Plummer1 , Jessica V. Redfern2 , Jameal F. Samhouri1 , Isaac D. Schroeder2 , Anthony D

26

California Mediterranean Rangelands and Ecosystem Conservation Lynn Huntsinger, Professor, Environmental Science, Policy and Management, MC 3110, University  

E-print Network

Mediterranean species. In this changed ecosystem, grazing and pastoral practices can benefit native wildlifeCalifornia Mediterranean Rangelands and Ecosystem Conservation Lynn Huntsinger, Professor, and land, livestock, and ecosystem service markets. Keywords: transhumance, oak woodlands, ecosystem

Kammen, Daniel M.

27

Mechanisms Controlling the Effects of Weather and Climate on California's Ecosystems (Invited)  

Microsoft Academic Search

We combined observations and manipulations along topographic gradients in southern and central California to understand how climate controls ecosystem function. California's topography causes large temperature and precipitation gradients as a result of orographic, rain-shadow, atmospheric lapse, and sea breeze effects. These gradients lead to a wide diversity of ecosystem types and provide a natural laboratory for understanding the controls on

M. Goulden; A. E. Kelly; A. Fellows; G. Winston

2010-01-01

28

Whither the Rangeland?: Protection and Conversion in California's Rangeland Ecosystems  

PubMed Central

Land use change in rangeland ecosystems is pervasive throughout the western United States with widespread ecological, social and economic implications. In California, rangeland habitats have high biodiversity value, provide significant habitat connectivity and form the foundation for a number of ecosystem services. To comprehensively assess the conservation status of these habitats, we analyzed the extent and drivers of habitat loss and the degree of protection against future loss across a 13.5 M ha study area in California. We analyzed rangeland conversion between 1984 and 2008 using time series GIS data and classified resulting land uses with aerial imagery. In total, over 195,000 hectares of rangeland habitats were converted during this period. The majority of conversions were to residential and associated commercial development (49% of the area converted), but agricultural intensification was surprisingly extensive and diverse (40% across six categories). Voluntary enrollment in an agricultural tax incentive program provided widespread protection from residential and commercial conversions across 37% of the remaining rangeland habitat extent (7.5 M ha), though this program did not protect rangeland from conversion to more intensive agricultural uses. Additionally, 24% of the remaining rangeland was protected by private conservation organizations or public agencies through land or easement ownership while 38% had no protection status at all. By developing a spatial method to analyze the drivers of loss and patterns of protection, this study demonstrates a novel approach to prioritize conservation strategies and implementation locations to avert habitat conversion. We propose that this approach can be used in other ecosystem types, and can serve as a regional conservation baseline assessment to focus strategies to effect widespread, cost-effective conservation solutions. PMID:25141171

Cameron, D. Richard; Marty, Jaymee; Holland, Robert F.

2014-01-01

29

Avian Conservation Practices Strengthen Ecosystem Services in California Vineyards  

PubMed Central

Insectivorous Western Bluebirds (Sialia mexicana) occupy vineyard nest boxes established by California winegrape growers who want to encourage avian conservation. Experimentally, the provision of available nest sites serves as an alternative to exclosure methods for isolating the potential ecosystem services provided by foraging birds. We compared the abundance and species richness of avian foragers and removal rates of sentinel prey in treatments with songbird nest boxes and controls without nest boxes. The average species richness of avian insectivores increased by over 50 percent compared to controls. Insectivorous bird density nearly quadrupled, primarily due to a tenfold increase in Western Bluebird abundance. In contrast, there was no significant difference in the abundance of omnivorous or granivorous bird species some of which opportunistically forage on grapes. In a sentinel prey experiment, 2.4 times more live beet armyworms (Spodoptera exigua) were removed in the nest box treatment than in the control. As an estimate of the maximum foraging services provided by insectivorous birds, we found that larval removal rates measured immediately below occupied boxes averaged 3.5 times greater than in the control. Consequently the presence of Western Bluebirds in vineyard nest boxes strengthened ecosystem services to winegrape growers, illustrating a benefit of agroecological conservation practices. Predator addition and sentinel prey experiments lack some disadvantages of predator exclusion experiments and were robust methodologies for detecting ecosystem services. PMID:22096555

Jedlicka, Julie A.; Greenberg, Russell; Letourneau, Deborah K.

2011-01-01

30

Avian conservation practices strengthen ecosystem services in California vineyards.  

PubMed

Insectivorous Western Bluebirds (Sialia mexicana) occupy vineyard nest boxes established by California winegrape growers who want to encourage avian conservation. Experimentally, the provision of available nest sites serves as an alternative to exclosure methods for isolating the potential ecosystem services provided by foraging birds. We compared the abundance and species richness of avian foragers and removal rates of sentinel prey in treatments with songbird nest boxes and controls without nest boxes. The average species richness of avian insectivores increased by over 50 percent compared to controls. Insectivorous bird density nearly quadrupled, primarily due to a tenfold increase in Western Bluebird abundance. In contrast, there was no significant difference in the abundance of omnivorous or granivorous bird species some of which opportunistically forage on grapes. In a sentinel prey experiment, 2.4 times more live beet armyworms (Spodoptera exigua) were removed in the nest box treatment than in the control. As an estimate of the maximum foraging services provided by insectivorous birds, we found that larval removal rates measured immediately below occupied boxes averaged 3.5 times greater than in the control. Consequently the presence of Western Bluebirds in vineyard nest boxes strengthened ecosystem services to winegrape growers, illustrating a benefit of agroecological conservation practices. Predator addition and sentinel prey experiments lack some disadvantages of predator exclusion experiments and were robust methodologies for detecting ecosystem services. PMID:22096555

Jedlicka, Julie A; Greenberg, Russell; Letourneau, Deborah K

2011-01-01

31

Climate Change in Mountain Ecosystems Areas of Current Research  

E-print Network

Climate Change in Mountain Ecosystems Areas of Current Research · Glacier Research · Snow Initiative Glacier Research A Focus on Mountain Ecosystems Climate change is widely acknowledged to be having in the western U.S. and the Northern Rockies in particular are highly sensitive to climate change. In fact

32

The Gulf of California: Review of ecosystem status and sustainability challenges  

NASA Astrophysics Data System (ADS)

The Gulf of California is unique because of its geographical location and conformation. It hosts diverse ecosystems and important fisheries that support industry and provide livelihood to coastal settlements. It is also the site of interests and problems, and an intense interaction among managers, producers, and conservationists. In this report, we scrutinize the abiotic (hydrography, climate, ocean circulation, and chemistry) and biotic (phyto- and zooplankton, fish, invertebrates, marine mammals, birds, and turtles) components of the marine ecosystem, and some particular aspects of climate variability, endemisms, harmful algal blooms, oxygen minimum layer, and pollution. We also review the current conditions and conflicts around the main fisheries (shrimp, small and large pelagic fishes, squid, artisanal and sportfishing), the most important human activity in the Gulf of California. We cover some aspects of management and conservation of fisheries, especially the claimed overexploitation of fish resources and the ecosystems, and review proposals for creating networks of marine protected areas. We conclude by identifying main needs for information and research, particularly the integration of data bases, the implementation of models and paleoreconstructions, establishment of monitoring programs, and the evaluation of fishing impacts and management actions.

Lluch-Cota, Salvador E.; Aragón-Noriega, Eugenio A.; Arreguín-Sánchez, Francisco; Aurioles-Gamboa, David; Jesús Bautista-Romero, J.; Brusca, Richard C.; Cervantes-Duarte, Rafael; Cortés-Altamirano, Roberto; Del-Monte-Luna, Pablo; Esquivel-Herrera, Alfonso; Fernández, Guillermo; Hendrickx, Michel E.; Hernández-Vázquez, Sergio; Herrera-Cervantes, Hugo; Kahru, Mati; Lavín, Miguel; Lluch-Belda, Daniel; Lluch-Cota, Daniel B.; López-Martínez, Juana; Marinone, Silvio G.; Nevárez-Martínez, Manuel O.; Ortega-García, Sofia; Palacios-Castro, Eduardo; Parés-Sierra, Alejandro; Ponce-Díaz, Germán; Ramírez-Rodríguez, Mauricio; Salinas-Zavala, Cesar A.; Schwartzlose, Richard A.; Sierra-Beltrán, Arturo P.

2007-04-01

33

Ecosystem Change in California Grasslands: Impacts of Species Invasion  

NASA Astrophysics Data System (ADS)

Grassland ecosystems of California have undergone dramatic changes, resulting in the almost complete replacement of native perennial grasses by non-native annuals across millions of hectares of grassland habitat. Our research investigates the effects of this community shift on carbon, water and energy cycles at two sites in northern coastal California. Our goal was to understand how changes to California’s grasslands have affected climate through 1. shifting the balance of carbon storage between terrestrial stocks and the atmosphere, and 2. altering the water and energy regimes that heat or cool the earth's surface. To compare the processes that govern material exchange before and after annual grass invasion, we made use of sites where native vegetation is found adjacent to locations that have undergone non-native invasion. In plots of each vegetation type, we monitored whole plant productivity, root and litter decay rates and soil respiration, as well as soil climatic controls on these processes. At one site, we also measured surface albedo and the components of the surface energy balance in each grass community, using the surface renewal method. Although seemingly subtle, the shift in California grassland communities from native perennial to non-native annual grass dominance has had profound consequences for ecosystem biogeochemical, radiative and hydrological cycles. Soil carbon storage was found to be significantly greater in native perennial grass communities. Across both study sites, we found that non-native grass invasion has resulted in the transfer of from 3 to 6 tons of carbon per hectare from the soil to the atmosphere, dependent on site and species. A soil density fractionation and a radiocarbon analysis also revealed the carbon to be more recalcitrant in native grass dominated locations. The primary plant traits that help explain why soil carbon losses follow annual grass invasion are: 1. differences between annual and perennial grasses in above/ belowground allocation, 2. differences in growth plasticity in response to inter-annual precipitation variability, and 3. the effect of differences in rooting depth and aboveground morphology on soil moisture content and soil respiration. Over the years 2004-2006, we found energy partitioning into latent and sensible heat flux to be similar among annual and perennial grass communities during periods of sufficient soil moisture availability. When water becomes scarce in the late spring, however, and annual grasses die, the ratio of latent to sensible heat loss is reduced in annual grass communities relative to perennials. The deep roots of perennial grasses prolong the period over which transpiration occurs. We also found that albedo differs year-round between perennial and annual grasses, tracking differences in grass phenology. Albedo differences are at a maximum during the summer and autumn months. At this time, the lower albedo in non-native annual communities can raise near surface temperatures up to 6 oC midday relative to native perennials.

Koteen, L. E.; Harte, J.; Baldocchi, D. D.

2009-12-01

34

Persistence of chlorinated hydrocarbon contamination in a California marine ecosystem  

SciTech Connect

Despite major reductions in the dominant DDT and polychlorinated biphenyls (PCB) input off Los Angeles (California, U.S.A.) in the early 1970s, the levels of these pollutants decreased only slightly from 1972 to 1975 both in surficial bottom sediments and in a flatfish bioindicator (Dover sole, Microstomus pacificus) collected near the submarine outfall. Concentrations of these pollutants in the soft tissues of the mussel Mytilus californianus, collected intertidally well inshore of the highly contaminated bottom sediments, followed much more closely the decreases in the outfall discharges. These observations suggest that contaminated sediments on the seafloor were the principal (although not necessarily direct) cause of the relatively high and persistent concentrations of DDT and PCB residues in tissues. The study indicated that residues of the higher-molecular-weight chlorinated hydrocarbons, such as DDT and PCB, can be highly persistent once released to coastal marine ecosystems and that their accumulation in surficial bottom sediments is the most likely cause of this persistence observed in the biota of the discharge zone.

Young, D.R.; Gossett, R.W.; Heesen, T.C.

1989-01-01

35

Evaluating Ecosystem Services Provided by Non-Native Species: An Experimental Test in California Grasslands  

PubMed Central

The concept of ecosystem services – the benefits that nature provides to human's society – has gained increasing attention over the past decade. Increasing global abiotic and biotic change, including species invasions, is threatening the secure delivery of these ecosystem services. Efficient evaluation methods of ecosystem services are urgently needed to improve our ability to determine management strategies and restoration goals in face of these new emerging ecosystems. Considering a range of multiple ecosystem functions may be a useful way to determine such strategies. We tested this framework experimentally in California grasslands, where large shifts in species composition have occurred since the late 1700's. We compared a suite of ecosystem functions within one historic native and two non-native species assemblages under different grazing intensities to address how different species assemblages vary in provisioning, regulatory and supporting ecosystem services. Forage production was reduced in one non-native assemblage (medusahead). Cultural ecosystem services, such as native species diversity, were inherently lower in both non-native assemblages, whereas most other services were maintained across grazing intensities. All systems provided similar ecosystem services under the highest grazing intensity treatment, which simulated unsustainable grazing intensity. We suggest that applying a more comprehensive ecosystem framework that considers multiple ecosystem services to evaluate new emerging ecosystems is a valuable tool to determine management goals and how to intervene in a changing ecosystem. PMID:25222028

Stein, Claudia; Hallett, Lauren M.; Harpole, W. Stanley; Suding, Katharine N.

2014-01-01

36

The California Current System in relation to the Northeast Pacific Ocean circulation  

NASA Astrophysics Data System (ADS)

The California Current System is described in its regional setting using two modern datasets. Argo provides a broadscale view of the entire eastern North Pacific Ocean for the period 2004-2010, and the High Resolution XBT Network includes transects from Honolulu to San Francisco (1991-2010) and to Los Angeles (2008-2010). Together these datasets describe a California Current of 500-800 km width extending along the coast from 43°N to 23°N. The mean southward transport of the California Current is about 5 Sv off Central and Southern California, with about 2.5 Sv of northward flow on its inshore side. Interannual variations are 50% or more of the mean transports. The salinity minimum in the core of the California Current is supplied by the North Pacific Current and by freshwater from the northern continental shelf and modified by alongshore geostrophic and across-shore Ekman advection as well as eddy fluxes and air-sea exchange. The heat and freshwater content of the California Current vary in response to the fluctuating strength of the alongshore geostrophic flow. On its offshore side, the California Current is influenced by North Pacific Intermediate Waters at its deepest levels and by Eastern Subtropical Mode Waters on shallower density surfaces. In total, the sources of the California Current, its alongshore advection, and its strong interactions with the inshore upwelling region and the offshore gyre interior combine to make this a rich and diverse ecosystem. The present work reviews previous contributions to the regional oceanography, and uses the new datasets to paint a spatially and temporally more comprehensive description than was possible previously.

Auad, Guillermo; Roemmich, Dean; Gilson, John

2011-12-01

37

The Economic Value of Coastal Ecosystems in California  

EPA Science Inventory

The status of marine ecosystems affects the well being of human societies. These ecosystems include but are not limited to estuaries, lagoons, reefs, and systems further offshore such as deep ocean vents. The coastal regions that connect terrestrial and marine ecosystems are of p...

38

A long term monitoring of Net Ecosystem Exchanges of the chaparral ecosystem in Southern California  

NASA Astrophysics Data System (ADS)

Arid and semiarid woody shrublands represent approximately 35% of the global terrestrial surface area and 24% of the global soil organic carbon, and 16% of the global aboveground biomass (Atjay et al., 1979; Shmida, 1985). Therefore, these areas potentially have a large contribution to the global carbon budget. However, the assessment of carbon uptake for the old-growth shrubland has remained largely unexplored. Therefore, a long-term observation of CO2 flux with the eddy covariance technique has started since 1997 at Sky Oaks Field Station in Southern California. The research site is categorized at the climatic gradient between desert and semiarid area and that experiences a Mediterranean climate. The long term record of CO2 flux showed the area has been a sink of CO2 of up to -0.2 kgCm-2yr-1. In addition to evaluating vertical carbon fluxes, we initiated a project to evaluate lateral carbon transports using litter traps, sediment fences and two small weirs adjacent to the eddy covariance site in 2011. Preliminary results indicate that the lateral carbon efflux from the system may offset the vertical influx to the shrub ecosystem. However, it is still necessary to develop the methodology to compare vertical carbon flux and the lateral carbon fluxes more accurately.

Rossi, A.; Oechel, W. C.; Murphy, P.; Ikawa, H.; Sturtevant, C. S.

2012-12-01

39

Long-term changes in pelagic tunicates of the California Current  

Microsoft Academic Search

This study analyzes interannual variability in springtime carbon biomass of pelagic tunicates (salps, doliolids, pyrosomes, and appendicularians) over the period 1951–2002 from CalCOFI zooplankton samples taken in the southern sector of the California Current System. The results provide evidence for ecosystem changes between 1976 and 1977 and perhaps between 1998 and 1999. A cool-phase group of salps (Salpa maxima, Pegea

Bertha E. Lavaniegos; Mark D. Ohman

2003-01-01

40

Sudden Oak Death: Endangering California and Oregon Forest Ecosystems  

Microsoft Academic Search

Sudden oak death is a new disease affecting tanoak (Lithocarpus densiflora) and oaks (Quercus spp) in California and Oregon, caused by the recently described pathogen Phytophthora ramorum. It has reached epi-demic proportions in several counties in central California, leading to the death of tens of thousands of trees. In addition to oaks and tanoak, P ramorum has been found in

David M. Rizzo; Matteo Garbelotto

2003-01-01

41

Anomalously warm July 2005 in the northern California Current: Historical context and the significance of cumulative wind stress  

E-print Network

a variety of biological effects, e.g., low early-season nutrients and chlorophyll [Hickey et al., 2006; J. A, relatively cold, saline, and nutrient-rich waters are brought up to shallower depths near the coast. Barth et al., Delayed upwelling alters coastal ocean ecosystems in the northern California Current, sub

Kurapov, Alexander

42

Effects of drought stress on microbial dynamics in seasonally dry California ecosystems  

NASA Astrophysics Data System (ADS)

One of the key environmental factors controlling microbial activity is moisture. This water limitation is particularly strong in semi-arid and arid ecosystems such as those found along California's coast and interior range-lands. Cool, wet winters separated by long, dry summers present some the most challenging conditions for microbial survival and growth. Infrequent pulses of precipitation directly control microbial dynamics through soil wet-dry cycles, which in turn control the export of materials and nutrients into streams and groundwater. Recent research suggests that living microbial biomass can increase during the driest, hottest part of the year. We measured dissolved organic carbon and nitrogen (DOC, DON), microbial biomass carbon and nitrogen, inorganic nitrogen (NH4+, NO3-), and nitrification potential from July of 2007 to the present in California semi-arid grasslands. We also monitored inorganic nitrogen concentrations in soil pore water, shallow ground water, and stream water over the same period. Seasonal trends in DOC and DON show that they accumulate over the dry summer, and then decrease with the onset of the winter rains. Microbial biomass carbon showed a similar pattern, being higher in the summer and declining during winter (188.94±13.34 and 139.21±8.45 ?g C g-1 dry soil respectively. However, biomass nitrogen remained unchanged over the same period (11.21±0.84 and 10.86±0.74 ?g N g-1 dry soil respectively). Nitrification potentials were lowest during the winter wet season (5.26±0.40 ?g N d-1 g-1 dry soil) and highest during the dry summer season (8.91±0.60 ?g N d-1 g-1 dry soil). However, the seasonal patterns in NH4+ and NO3- availability suggest that net nitrification was not substantial until after the winter rains began. It is not currently known whether this increase in biomass represents actual growth of new organisms, or is a result of microbes accumulating internal solutes to avoid drying out. At the landscape-scale, these microbial dynamics control the amount and composition of nutrient export from these ecosystems into groundwater and streams. Long, dry summers allow nutrients to accumulate, and then a single large precipitation event can lead to a large pulse being released. Microbial dynamics in natural ecosystems, such as NO3- production via nitrification, can have important implications for water quality (in the case of NO3-) in urban areas located downstream.

Schaeffer, S. M.; Boot, C. M.; Doyle, A.; Clark, J.; Schimel, J. P.

2008-12-01

43

CURRENT RESEARCH ON SPIROPLASMA CITRI IN CALIFORNIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stubborn disease, caused by Spiroplasma citri, has been a long-standing disease in most areas of California. Because of uneven distribution in the plant and seasonal fluctuations in titer, detection of stubborn by biological indexing or the traditional culture method is not always reliable. To optim...

44

In the Schools: California Treat: Three Days in Five Ecosystems.  

ERIC Educational Resources Information Center

Describes a 3-day program sponsored by the Orange County Marine Institute that provides biological, cultural, and historical learning experiences. Discusses the setting and activities of the five ecosystems explored by the students. The Chaparral to Ocean Science Camp includes chaparral, riparian, woodland, intertidal, and pelagic environments.…

Rigby, Jennifer A.

1986-01-01

45

California Coastal Upwelling Onset Variability: Cross-Shore and Bottom-Up Propagation in the Planktonic Ecosystem  

PubMed Central

The variability of the California Current System (CCS) is primarily driven by variability in regional wind forcing. In particular, the timing of the spring transition, i.e., the onset of upwelling-favorable winds, varies considerably in the CCS with changes in the North Pacific Gyre Oscillation. Using a coupled physical-biogeochemical model, this study examines the sensitivity of the ecosystem functioning in the CCS to a lead or lag in the spring transition. An early spring transition results in an increased vertical nutrient flux at the coast, with the largest ecosystem consequences, both in relative amplitude and persistence, hundreds of kilometers offshore and at the highest trophic level of the modeled food web. A budget analysis reveals that the propagation of the perturbation offshore and up the food web is driven by remineralization and grazing/predation involving both large and small plankton species. PMID:23690935

Chenillat, Fanny; Rivière, Pascal; Capet, Xavier; Franks, Peter J. S.; Blanke, Bruno

2013-01-01

46

PERSISTENCE OF CHLORINATED HYDROCARBON CONTAMINATION IN A CALIFORNIA MARINE ECOSYSTEM  

EPA Science Inventory

Despite major reductions in the dominant DDT and polychlorinated biphenyls (PCB) input off Los Angeles (California, USA) in the early 1970s, the levels of these pollutants decreased only slightly from 1972 to 1975 both in surficial bottom sediments and in a flatfish bioindicator ...

47

2013. Wetlands. In: Mooney, H. and Zavaleta, E., editors. Ecosystems of California: A Source Book. Berkeley, CA: University of California Press, p.  

Technology Transfer Automated Retrieval System (TEKTRAN)

This publication is an introduction to wetland ecosystems in California, their geographic distribution, and historical ecology. Hydroclimatology and hydrology are explained as key drivers and patterns of variability in wetland habitats and biological communities. Primary wetland types are describe...

48

Appreciation, Use, and Management of Biodiversity and Ecosystem Services in California's Working Landscapes  

NASA Astrophysics Data System (ADS)

"Working landscapes" is the concept of fostering effective ecosystem stewardship and conservation through active human presence and management and integrating livestock, crop, and timber production with the provision of a broad range of ecosystem services at the landscape scale. Based on a statewide survey of private landowners of "working" forests and rangelands in California, we investigated whether owners who are engaged in commercial livestock or timber production appreciate and manage biodiversity and ecosystem services on their land in different ways than purely residential owners. Both specific uses and management practices, as well as underlying attitudes and motivations toward biodiversity and ecosystem services, were assessed. Correlation analysis showed one bundle of ecosystem goods and services (e.g., livestock, timber, crops, and housing) that is supported by some landowners at the community level. Another closely correlated bundle of biodiversity and ecosystem services includes recreation, hunting/fishing, wildlife habitat, and fire prevention. Producers were more likely to ally with the first bundle and residential owners with the second. The survey further confirmed that cultural ecosystem services and quality-of-life aspects are among the primary amenities that motivate forest and rangeland ownership regardless of ownership type. To live near natural beauty was the most important motive for both landowner groups. Producers were much more active in management for habitat improvement and other environmental goals than residential owners. As the number of production-oriented owners decreases, developing strategies for encouraging environment-positive management by all types of landowners is crucial.

Plieninger, Tobias; Ferranto, Shasta; Huntsinger, Lynn; Kelly, Maggi; Getz, Christy

2012-09-01

49

Appreciation, use, and management of biodiversity and ecosystem services in California's working landscapes.  

PubMed

"Working landscapes" is the concept of fostering effective ecosystem stewardship and conservation through active human presence and management and integrating livestock, crop, and timber production with the provision of a broad range of ecosystem services at the landscape scale. Based on a statewide survey of private landowners of "working" forests and rangelands in California, we investigated whether owners who are engaged in commercial livestock or timber production appreciate and manage biodiversity and ecosystem services on their land in different ways than purely residential owners. Both specific uses and management practices, as well as underlying attitudes and motivations toward biodiversity and ecosystem services, were assessed. Correlation analysis showed one bundle of ecosystem goods and services (e.g., livestock, timber, crops, and housing) that is supported by some landowners at the community level. Another closely correlated bundle of biodiversity and ecosystem services includes recreation, hunting/fishing, wildlife habitat, and fire prevention. Producers were more likely to ally with the first bundle and residential owners with the second. The survey further confirmed that cultural ecosystem services and quality-of-life aspects are among the primary amenities that motivate forest and rangeland ownership regardless of ownership type. To live near natural beauty was the most important motive for both landowner groups. Producers were much more active in management for habitat improvement and other environmental goals than residential owners. As the number of production-oriented owners decreases, developing strategies for encouraging environment-positive management by all types of landowners is crucial. PMID:22767213

Plieninger, Tobias; Ferranto, Shasta; Huntsinger, Lynn; Kelly, Maggi; Getz, Christy

2012-09-01

50

Regime shifts in the Humboldt Current ecosystem [review article  

NASA Astrophysics Data System (ADS)

Of the four major eastern boundary currents, the Humboldt Current (HC) stands out because it is extremely productive, dominated by anchovy dynamics and subject to frequent direct environmental perturbations of the El Niño Southern Oscillation (ENSO). The long-term dynamics of the HC ecosystem are controlled by shifts between alternating anchovy and sardine regimes that restructure the entire ecosystem from phytoplankton to the top predators. These regime shifts are caused by lasting periods of warm or cold temperature anomalies related to the approach or retreat of warm subtropical oceanic waters to the coast of Peru and Chile. Phases with mainly negative temperature anomalies parallel anchovy regimes (1950-1970; 1985 to the present) and the rather warm period from 1970 to 1985 was characterized by sardine dominance. The transition periods (turning points) from one regime to the other were 1968-1970 and 1984-1986. Like an El Nino, the warm periods drastically change trophic relationships in the entire HC ecosystem, exposing the Peruvian anchovy to a multitude of adverse conditions. Positive temperature anomalies off Peru drive the anchovy population close to the coast as the coastal upwelling cells usually offer the coolest environment, thereby substantially decreasing the extent of the areas of anchovy distribution and spawning. This enhances the effects of negative density-dependent processes such as egg and larval cannibalism and dramatically increases its catchability. Increased spatial overlap between anchovies and the warmer water preferring sardines intensifies anchovy egg mortality further as sardines feed heavily on anchovy eggs. Food sources for juvenile and adult anchovies which prey on a mixed diet of phyto- and zooplankton are drastically reduced because of decreased plankton production due to restricted upwelling in warm years, as demonstrated by lower zooplankton and phytoplankton volumes and the diminution of the fraction of large copepods, their main food source. Horse mackerel and mackerel, the main predators of anchovy, increase predation pressure on juvenile and adult anchovies due to extended invasion into the anchovy habitat in warmer years. In contrast to these periods of warm and cold temperature anomalies on the decadal scale, ENSO events do not play an important role for long-term anchovy dynamics, as the anchovy can recover even from strong ENSO events within 1-2 years. Consequently, the strong 1972-1973 ENSO event (in combination with overfishing) was not the cause of the famous crash of the Peruvian anchovy fishery in the 1970s.

Alheit, Jürgen; Niquen, Miguel

2004-02-01

51

Land use change and effects on water quality and ecosystem health in the Lake Tahoe basin, Nevada and California  

USGS Publications Warehouse

Human activity in the Lake Tahoe Basin has increased substantially in the past four decades, causing significant impacts on the quality and clarity of the lake's famous deep, clear water. Protection of Lake Tahoe and the surrounding environment has become an important activity in recent years. A variety of agencies, including the Tahoe Regional Planning Agency, Tahoe Research Group of the University of California at Davis, Desert Research Institute of the University and Community College System of Nevada, U.S. Geological Survey (USGS), and a host of State (both Nevada and California) and local agencies have been monitoring and conducting research in the Basin in order to understand how the lake functions and to what extent humans have affected its landscape and ecosystem processes. In spite of all of these activities, there remains a lack of comprehensive land use change data and analysis for the Basin. A project is underway that unites the land cover mapping expertise of the USGS National Mapping Discipline with the hydrologic expertise of the Water Resources Discipline to assess the impacts of urban growth and land use change in the Lake Tahoe Basin. Three activities are planned over the next 3 years: (1) mapping the current and historic state of the land surface, (2) conducting analysis to document patterns, rates, and trends in urbanization, land use change, and ecosystem health, and (3) assessing the causes and consequences of land use change with regard to water quality and ecosystem health. We hypothesize that changes in the extent of urban growth and the corresponding increases in impervious surfaces and decreases in natural vegetation have resulted in severe impacts on ecosystem health and integrity, riparian zones and water quality over time. We are acting on multiple fronts to test this hypothesis through the quantification of landscape disturbances and impacts.

Forney, William; Richards, Lora; Adams, Kenneth D.; Minor, Timothy B.; Rowe, Timothy G.; Smith, J. LaRue; Raumann, Christian G.

2001-01-01

52

Turbulence Mixing and Transport Mechanisms in a Coastal Ecosystem: Bay of La Paz, Baja California Sur, Mexico  

E-print Network

ABSTRACT Turbulence Mixing and Transport Mechanisms in a Coastal Ecosystem: Bay of La Paz, Baja California Sur, Mexico. (May 2014) Burkely Ashton Pettijohn Department of Marine Sciences Texas A&M University Research Advisor: Dr. Ayal Anis...

Pettijohn, Burkely Ashton

2014-02-10

53

Compound-specific ?15N amino acid measurements in littoral mussels in the California upwelling ecosystem: a new approach to generating baseline ?15N Isoscapes for coastal ecosystems.  

PubMed

We explored ?(15)N compound-specific amino acid isotope data (CSI-AA) in filter-feeding intertidal mussels (Mytilus californianus) as a new approach to construct integrated isoscapes of coastal primary production. We examined spatial ?(15)N gradients in the California Upwelling Ecosystem (CUE), determining bulk ?(15)N values of mussel tissue from 28 sites between Port Orford, Oregon and La Jolla, California, and applying CSI-AA at selected sites to decouple trophic effects from isotopic values at the base of the food web. Bulk ?(15)N values showed a strong linear trend with latitude, increasing from North to South (from ? 7‰ to ? 12‰, R(2) = 0.759). In contrast, CSI-AA trophic position estimates showed no correlation with latitude. The ?(15)N trend is therefore most consistent with a baseline ?(15)N gradient, likely due to the mixing of two source waters: low ?(15)N nitrate from the southward flowing surface California Current, and the northward transport of the California Undercurrent (CUC), with (15)N-enriched nitrate. This interpretation is strongly supported by a similar linear gradient in ?(15)N values of phenylalanine (?(15)NPhe), the best AA proxy for baseline ?(15)N values. We hypothesize ?(15)N(Phe) values in intertidal mussels can approximate annual integrated ?(15)N values of coastal phytoplankton primary production. We therefore used ?(15)N(Phe) values to generate the first compound-specific nitrogen isoscape for the coastal Northeast Pacific, which indicates a remarkably linear gradient in coastal primary production ?(15)N values. We propose that ?(15)N(Phe) isoscapes derived from filter feeders can directly characterize baseline ?(15)N values across major biochemical provinces, with potential applications for understanding migratory and feeding patterns of top predators, monitoring effects of climate change, and study of paleo- archives. PMID:24887109

Vokhshoori, Natasha L; McCarthy, Matthew D

2014-01-01

54

Compound-Specific ?15N Amino Acid Measurements in Littoral Mussels in the California Upwelling Ecosystem: A New Approach to Generating Baseline ?15N Isoscapes for Coastal Ecosystems  

PubMed Central

We explored ?15N compound-specific amino acid isotope data (CSI-AA) in filter-feeding intertidal mussels (Mytilus californianus) as a new approach to construct integrated isoscapes of coastal primary production. We examined spatial ?15N gradients in the California Upwelling Ecosystem (CUE), determining bulk ?15N values of mussel tissue from 28 sites between Port Orford, Oregon and La Jolla, California, and applying CSI-AA at selected sites to decouple trophic effects from isotopic values at the base of the food web. Bulk ?15N values showed a strong linear trend with latitude, increasing from North to South (from ?7‰ to ?12‰, R2?=?0.759). In contrast, CSI-AA trophic position estimates showed no correlation with latitude. The ?15N trend is therefore most consistent with a baseline ?15N gradient, likely due to the mixing of two source waters: low ?15N nitrate from the southward flowing surface California Current, and the northward transport of the California Undercurrent (CUC), with15N-enriched nitrate. This interpretation is strongly supported by a similar linear gradient in ?15N values of phenylalanine (?15NPhe), the best AA proxy for baseline ?15N values. We hypothesize ?15NPhe values in intertidal mussels can approximate annual integrated ?15N values of coastal phytoplankton primary production. We therefore used ?15NPhe values to generate the first compound-specific nitrogen isoscape for the coastal Northeast Pacific, which indicates a remarkably linear gradient in coastal primary production ?15N values. We propose that ?15NPhe isoscapes derived from filter feeders can directly characterize baseline ?15N values across major biochemical provinces, with potential applications for understanding migratory and feeding patterns of top predators, monitoring effects of climate change, and study of paleo- archives. PMID:24887109

Vokhshoori, Natasha L.; McCarthy, Matthew D.

2014-01-01

55

California Current System response to late Holocene climate cooling in southern California  

Microsoft Academic Search

New Holocene high-resolution planktonic foraminiferal assemblage data from Santa Barbara Basin, California documents variability in ocean circulation as the California Current System responded to millennial-scale climate change during late Holocene climatic cooling. Climatic variability increased at 4 ka when a series of extreme cool events (notably at 2.2, 1.5 and 0.8 ka) associated with glacial advance in the Pacific Northwest

J. Fisler; I. L. Hendy

2008-01-01

56

Global Circulation and the California Current  

NSDL National Science Digital Library

This computer-based lesson provides information on ocean currents, circulation and atmospheric influences. Several sections cover "drift" studies, including the famous Nike Tennis Shoe study. Each segment provides relevant information and gives students questions to answer. Incorrect responses result in more information. This unit is part of an on-line course in general oceanography offered at San Jose State University.

1999-03-21

57

Current California Drought: Impact on Citrus Trees and Potential Mitigation  

Technology Transfer Automated Retrieval System (TEKTRAN)

California is in another cycle of extended drought. The article reviews and discusses likely impact of the current drought on citrus growers and potential mitigation techniques. Citrus physiological responses to water stress is briefly reviewed. The direct impact of drought on citrus is reduced frui...

58

Climate, fishing, and fluctuations of sardine and anchovy in the California Current  

PubMed Central

Since the days of Elton, population cycles have challenged ecologists and resource managers. Although the underlying mechanisms remain debated, theory holds that both density-dependent and density-independent processes shape the dynamics. One striking example is the large-scale fluctuations of sardine and anchovy observed across the major upwelling areas of the world. Despite a long history of research, the causes of these fluctuations remain unresolved and heavily debated, with significant implications for fisheries management. We here model the underlying causes of these fluctuations, using the California Current Ecosystem as a case study, and show that the dynamics, accurately reproduced since A.D. 1661 onward, are explained by interacting density-dependent processes (i.e., through species-specific life-history traits) and climate forcing. Furthermore, we demonstrate how fishing modifies the dynamics and show that the sardine collapse of the 1950s was largely unavoidable given poor recruitment conditions. Our approach provides unique insight into the origin of sardine–anchovy fluctuations and a knowledge base for sustainable fisheries management in the California Current Ecosystem and beyond. PMID:23836661

Lindegren, Martin; Checkley, David M.; Rouyer, Tristan; MacCall, Alec D.; Stenseth, Nils Chr.

2013-01-01

59

Material properties of zooplankton and nekton from the California current  

NASA Astrophysics Data System (ADS)

This study measured the material properties of zooplankton, Pacific hake (Merluccius productus), Humboldt squid (Dosidicus gigas), and two species of myctophids (Symbolophorus californiensis and Diaphus theta) collected from the California Current ecosystem. The density contrast (g) was measured for euphausiids, decapods (Sergestes similis), amphipods (Primno macropa, Phronima sp., and Hyperiid spp.), siphonophore bracts, chaetognaths, larval fish, crab megalopae, larval squid, and medusae. Morphometric data (length, width, and height) were collected for these taxa. Density contrasts varied within and between zooplankton taxa. The mean and standard deviation for euphausiid density contrast were 1.059 +/- 0.009. Relationships between zooplankton density contrast and morphometric measurements, geographic location, and environmental conditions were investigated. Site had a significant effect on euphausiid density contrast. Density contrasts of euphausiids collected in the same geographic area approximately 4-10 days apart were significantly higher (p < 0.001). Sound speed contrast (h) was measured for euphausiids and pelagic decapods (S. similis) and it varied between taxa. The mean and standard deviation for euphausiid sound speed were 1.019 +/- 0.009. Euphausiid mass was calculated from density measurements and volume, and a relationship between euphausiid mass and length was produced. We determined that euphausiid from volumes could be accurately estimated two dimensional measurements of animal body shape, and that biomass (or biovolume) could be accurately calculated from digital photographs of animals. Density contrast (g) was measured for zooplankton, pieces of hake flesh, myctophid flesh, and of the following Humboldt squid body parts: mantle, arms, tentacle, braincase, eyes, pen, and beak. The density contrasts varied within and between fish taxa, as well as among squid body parts. Effects of animal length and environmental conditions on nekton density contrast were investigated. The sound speed contrast (h) was measured for Pacific hake flesh, myctophid flesh, Humboldt squid mantle, and Humboldt squid braincase. Sound speed varied within and between nekton taxa. The material properties reported in this study can be used to improve target strength estimates from acoustic scattering models which would increase the accuracy of biomass estimates from acoustic surveys for these zooplankton and nekton.

Becker, Kaylyn

60

Mechanisms Controlling the Effects of Weather and Climate on California's Ecosystems (Invited)  

NASA Astrophysics Data System (ADS)

We combined observations and manipulations along topographic gradients in southern and central California to understand how climate controls ecosystem function. California's topography causes large temperature and precipitation gradients as a result of orographic, rain-shadow, atmospheric lapse, and sea breeze effects. These gradients lead to a wide diversity of ecosystem types and provide a natural laboratory for understanding the controls on plant community composition and ecosystem function. Findings include: (1) Natural climate gradients drive large changes in species composition, plant phenology, growing season length, and primary production. The growing season at low, dry, and warm locations is limited by summer drought, resulting in low primary production. The growing season at high, wet, and cold locations is limited by winter cold, resulting in low primary production. The growing season at mid elevation is limited by neither summer drought nor winter cold, resulting in year-round and high primary production. (2) The relative importance of plant species within a community shifts rapidly in response to changes in water input, caused by either natural variability or experimental manipulation. Species that are intolerant of drier conditions decline rapidly with reduced water input, and may disappear locally; species that are tolerant of drier conditions increase rapidly in extent. (3) Inward plant migration, and the establishment of new species at a location, is a comparatively slow process. The initial phases of climate change will likely reshuffle the importance of existing species within the community, resulting in only modest changes in ecosystem function but possibly extirpating species that are intolerant of warmer and drier conditions, and reducing biodiversity. These declines in biodiversity and delays in species immigration may ultimately limit the ability of ecosystems to respond to subsequent interannual and decadal variations in weather, and to adjust to more extreme changes in climate.

Goulden, M.; Kelly, A. E.; Fellows, A.; Winston, G.

2010-12-01

61

Surface Drift of RAFOS Floats in the California Current System  

NASA Astrophysics Data System (ADS)

The patterns of surface drift of ninety RAFOS floats in the California Current System have been studied. The floats were launched in the California Undercurrent during 1992-2010 and were tracked by the ARGOS system when they surfaced at the end of their subsurface mission. The float hulls were glass cylinders which were 8.6 cm wide by 1.52 m long and floated with the upper 30 cm of the hull above water. The surface drift of these floats was typically equatorward in the California Current. However, some floats would flow poleward, others would drift westward into the North Pacific Gyre, and others with orbital cyclonic and/or anti-cyclonic motions. The duration of surface trajectories varied from as short as a period of days to approximately ten months. Forces on the floats included wind stress on the exposed hull and the drag of ocean currents on the subsurface hull. The latter included the Stokes drift associated with surface wind waves, Ekman flow caused by the stress of the wind on the ocean surface, and the currents associated with the general circulation of the ocean. Surface currents can be explained by calculating current direction and velocity from wind stress data. As a first step, the relationship between observed wind stress and the motion of the float is determined by assuming Ekman balance. Mesoscale effects, including eddies, are also considered in explaining the surface drift of the floats.

Gates, D. C.; Collins, C. A.; Margolina, T.

2011-12-01

62

Zooplankton distribution and cross-shelf transfer of carbon in an area of complex mesoscale circulation in the northern California Current  

Microsoft Academic Search

We conducted a research cruise in late summer (July–August) 2000 to study the effect of mesoscale circulation features on zooplankton distributions in the coastal upwelling ecosystem of the northern California Current. Our study area was in a region of complex coastline and bottom topography between Newport, Oregon (44.7°N), and Crescent City, California (41.9°N). Winds were generally strong and equatorward for

J. E. Keister; W. T. Peterson; S. D. Pierce

2009-01-01

63

California current eddy formation: ship, air, and satellite results.  

PubMed

Until recently, quantitative measurements of the circulation of the California Current were limited to hydrographic determinations [See figure in the PDF file] of temperature and salinity. This information is now being augmented by satellite data. Clouds permitting, satellite scanner systems can locate major ocean frontal boundaries if they are associated with even quite weak horizontal sea-surface temperature gradients. The satellite data are most usefully interpreted in a region such as that encompassing the California Current, where the surface and main thermocline temperature distributions bear some relation to each other. In such a region, it is possible to make interpretations of circulation based on satellite-derived sea-surface temperature patterns. The correctness of these interpretations depends heavily on the availability of historical and present-day subsurface data, collected by conventional methods from ships and aircraft. Satellite infrared scanners, in addition to providing information on circulation with vastly increased spatial resolution, have the potential (with cooperative weather) for providing increased time resolution. These improvements in resolution have permitted us to see that much of the spatial variation in the California Current takes place along welldefined fronts and to observe the evolution of one particular meander. PMID:17844599

Bernstein, R L; Breaker, L; Whritner, R

1977-01-28

64

SAFRR Tsunami Scenario. Preparedness and Resilience for California's ecosystems, natural resources, and the communities that depend on them  

NASA Astrophysics Data System (ADS)

The SAFRR Tsunami Scenario models a plausible 9.1MP earthquake occuring off the Alaskan coast, that generates a tsunami forecast to strike California between 4-6 hour after the event. California's diverse ecosystems, natural resources, and sensitive species will be significantly affected. Although often overlooked in disaster risk reduction, damage to ecosystems and natural resources during hazards including tsunamis, has often resulted in serious impacts to natural systems and on humans who depend on them. SAFRR tsunami scenario forecasts of wave amplitude, water velocity and inundation and overlain on GIS maps were analyzed to identify plausible impacts on California's ecosystems including beaches, marshes, nearshore subtidal habitats, as well as parks and reserves. The effect on natural resources including fisheries was evaluated. Recovery times and consequences were analyzed. The results illustrate the value and vulnerability of these resources and guidelines for preparation and mitigation are discussed.

Brosnan, D. M.

2013-12-01

65

Biodiversity and Ecosystem Functioning: Current Knowledge and Future Challenges  

Microsoft Academic Search

The ecological consequences of biodiversity loss have aroused considerable interest and controversy during the past decade. Major advances have been made in describing the relationship between species diversity and ecosystem processes, in identifying functionally important species, and in revealing underlying mechanisms. There is, however, uncertainty as to how results obtained in recent experiments scale up to landscape and regional levels

M. Loreau; S. Naeem; P. Inchausti; J. Bengtsson; J. P. Grime; A. Hector; D. U. Hooper; M. A. Huston; D. Raffaelli; B. Schmid; D. Tilman; D. A. Wardle

2001-01-01

66

Biodiversity and Ecosystem Functioning: Current Knowledge and Future Challenges  

Microsoft Academic Search

The ecological consequences of biodiversity loss have aroused considerable interest and controversy during the past decade. Major advances have been made in describing the relationship between species diversity and ecosystem processes, in identifying functionally important species, and in revealing underlying mechanisms. There is, however, uncertainty as to how results obtained in recent experiments scale up to landscape and regional levels

M. Loreau; S. Naeem; P. Inchausti; J. Bengtsson; J. P. Grime; A. Hector; D. U. Hooper; M. A. Huston; D. Raffaelli; B. Schmid; D. Tilman; D. A. Wardle

1998-01-01

67

PROFESSIONAL INTERESTS Forest ecology, with an emphasis on productivity, biogeochemistry, and ecosystem dynamics. Current areas of research  

E-print Network

April 2012 PROFESSIONAL INTERESTS Forest ecology, with an emphasis on productivity, biogeochemistry, and ecosystem dynamics. Current areas of research focus on longterm changes in ecosystems including restoration ecology, productivity, and nutrient cycling. Major current projects include projects

Binkley, Dan

68

California nearshore processes - ERTS 1. [coastal currents and sediments  

NASA Technical Reports Server (NTRS)

The detectability of many nearshore processes from ERTS is made possible due to the suspended sediment present in the coastal waters. From viewing and analyzing the California coastal imagery collected during the last year and a half, the overall current patterns and their changes have become evident. It is now possible to map monthly and seasonal changes that occur throughout the year. The original objectives of detecting currents, sediment transport, estuaries and river discharge have now been expanded to include the use of ERTS information in operational problems of the U.S. Army Corps of Engineers. This incorporates the detected nearshore features into planning and organizing shore protection facilities.

Steller, D. D.; Pirie, D. M.

1974-01-01

69

Multivariate ocean-climate indicators (MOCI) for the central California Current: Environmental change, 1990-2010  

NASA Astrophysics Data System (ADS)

Temporal environmental variability may confound interpretations of management actions, such as reduced fisheries mortality when Marine Protected Areas are implemented. To aid in the evaluation of recent ecosystem protection decisions in central-northern California, we designed and implemented multivariate ocean-climate indicators (MOCI) of environmental variability. To assess the validity of the MOCI, we evaluated interannual and longer-term variability in relation to previously recognized environmental variability in the region, and correlated MOCI to a suite of biological indicators including proxies for lower- (phytoplankton, copepods, krill), and upper-level (seabirds) taxa. To develop the MOCI, we selected, compiled, and synthesized 14 well-known atmospheric and oceanographic indicators of large-scale and regional processes (transport and upwelling), as well as local atmospheric and oceanic response variables such as wind stress, sea surface temperature, and salinity. We derived seasonally-stratified MOCI using principal component analysis. Over the 21-year study period (1990-2010), the ENSO cycle weakened while extra-tropical influences increased with a strengthening of the North Pacific Gyre Oscillation (NPGO) and cooling of the Pacific Decadal Oscillation (PDO). Correspondingly, the Northern Oscillation Index (NOI) strengthened, leading to enhanced upwelling-favorable wind stress and cooling of air and ocean surface temperatures. The seasonal MOCI related well to subarctic copepod biomass and seabird productivity, but poorly to chlorophyll-a concentration and krill abundance. Our results support a hypothesis of enhanced sub-arctic influence (transport from the north) and upwelling intensification in north-central California over the past two decades. Such environmental conditions may favor population growth for species with sub-arctic zoogeographic affinities within the central-northern California Current coastal ecosystem.

Sydeman, William J.; Thompson, Sarah Ann; García-Reyes, Marisol; Kahru, Mati; Peterson, William T.; Largier, John L.

2014-01-01

70

Accumulation of current-use and organochlorine pesticides in crab embryos from Northern California, USA  

USGS Publications Warehouse

Invertebrates have long been used as resident sentinels for assessing ecosystem health and productivity. The shore crabs, Hemigrapsus oregonensis and Pachygrapsus crassipes, are abundant in estuaries and beaches throughout northern California, USA and have been used as indicators of habitat conditions in several salt marshes. The overall objectives of the present study were to conduct a lab-based study to test the accumulation of current-use pesticides, validate the analytical method and to analyze field-collected crabs for a suite of 74 current-use and legacy pesticides. A simple laboratory uptake study was designed to determine if embryos could bioconcentrate the herbicide molinate over a 7-d period. At the end of the experiment, embryos were removed from the crabs and analyzed by gas chromatography/mass spectrometry. Although relatively hydrophilic (log KOW of 2.9), molinate did accumulate with an estimated bioconcentration factor (log BCF) of approximately 2.5. Following method validation, embryos were collected from two different Northern California salt marshes and analyzed. In field-collected embryos 18 current-use and eight organochlorine pesticides were detected including synthetic pyrethroids and organophosphate insecticides, as well as DDT and its degradates. Lipid-normalized concentrations of the pesticides detected in the field-collected crab embryos ranged from 0.1 to 4 ppm. Pesticide concentrations and profiles in crab embryos were site specific and could be correlated to differences in land-use practices. These preliminary results indicate that embryos are an effective sink for organic contaminants in the environment and have the potential to be good indicators of ecosystem health, especially when contaminant body burden analyses are paired with reproductive impairment assays.

Smalling, Kelly L.; Morgan, Steven; Kuivila, Kathryn K.

2010-01-01

71

Estimating California ecosystem carbon change using process model and land cover disturbance data: 1951-2000  

USGS Publications Warehouse

Land use change, natural disturbance, and climate change directly alter ecosystem productivity and carbon stock level. The estimation of ecosystem carbon dynamics depends on the quality of land cover change data and the effectiveness of the ecosystem models that represent the vegetation growth processes and disturbance effects. We used the Integrated Biosphere Simulator (IBIS) and a set of 30- to 60-m resolution fire and land cover change data to examine the carbon changes of California's forests, shrublands, and grasslands. Simulation results indicate that during 1951-2000, the net primary productivity (NPP) increased by 7%, from 72.2 to 77.1TgCyr-1 (1 teragram=1012g), mainly due to CO2 fertilization, since the climate hardly changed during this period. Similarly, heterotrophic respiration increased by 5%, from 69.4 to 73.1TgCyr-1, mainly due to increased forest soil carbon and temperature. Net ecosystem production (NEP) was highly variable in the 50-year period but on average equalled 3.0TgCyr-1 (total of 149TgC). As with NEP, the net biome production (NBP) was also highly variable but averaged -0.55TgCyr-1 (total of -27.3TgC) because NBP in the 1980s was very low (-5.34TgCyr-1). During the study period, a total of 126Tg carbon were removed by logging and land use change, and 50Tg carbon were directly removed by wildland fires. For carbon pools, the estimated total living upper canopy (tree) biomass decreased from 928 to 834TgC, and the understory (including shrub and grass) biomass increased from 59 to 63TgC. Soil carbon and dead biomass carbon increased from 1136 to 1197TgC. Our analyses suggest that both natural and human processes have significant influence on the carbon change in California. During 1951-2000, climate interannual variability was the key driving force for the large interannual changes of ecosystem carbon source and sink at the state level, while logging and fire were the dominant driving forces for carbon balances in several specific ecoregions. From a long-term perspective, CO2 fertilization plays a key role in maintaining higher NPP. However, our study shows that the increase in C sequestration by CO2 fertilization is largely offset by logging/land use change and wildland fires. ?? 2011 Elsevier B.V.

Liu, J.; Vogelmann, J.E.; Zhu, Z.; Key, C.H.; Sleeter, B.M.; Price, D.T.; Chen, J.M.; Cochrane, M.A.; Eidenshink, J.C.; Howard, S.M.; Bliss, N.B.; Jiang, H.

2011-01-01

72

Spatial ecology of krill, micronekton and top predators in the central California Current: Implications for defining ecologically important areas  

NASA Astrophysics Data System (ADS)

Marine spatial planning and ecosystem models that aim to predict and protect fisheries and wildlife benefit greatly from syntheses of empirical information on physical and biological partitioning of marine ecosystems. Here, we develop spatially-explicit oceanographic and ecological descriptions of the central California Current region. To partition this region, we integrate data from 20 years of shipboard surveys with satellite remote-sensing to characterize local seascapes of ecological significance, focusing on krill, other micronekton taxa, and top predators (seabirds and marine mammals). Specifically, we investigate if micronekton and predator assemblages co-vary spatially with mesoscale oceanographic conditions. The first principal component of environmental and micronekton seascapes indicates significant coupling between physics, primary productivity, and secondary and tertiary marine consumers. Subsequent principal components indicate latitudinal variability in niche-community space due to varying habitat characteristics between Monterey Bay (deep submarine canyon system) and the Gulf of the Farallones (extensive continental shelf), even though both of these sub-regions are located downstream from upwelling centers. Overall, we identified five ecologically important areas based on spatial integration of environmental and biotic features. These areas, characterized by proximity to upwelling centers, shallow pycnoclines, and high chlorophyll-a and krill concentrations, are potential areas of elevated trophic focusing for specific epipelagic and mesopelagic communities. This synthesis will benefit ecosystem-based management approaches for the central California Current, a region long-impacted by anthropogenic factors.

Santora, Jarrod A.; Field, John C.; Schroeder, Isaac D.; Sakuma, Keith M.; Wells, Brian K.; Sydeman, William J.

2012-11-01

73

Modeling Hawaiian ecosystem degradation due to invasive plants under current and future climates  

USGS Publications Warehouse

Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with 0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions.

Vorsino, Adam E.; Fortini, Lucas B.; Amidon, Fred A.; Miller, Stephen E.; Jacobi, James D.; Price, Jonathan P.; `Ohukani`ohi`a Gon, Sam, III; Koob, Gregory A.

2014-01-01

74

Anthropogenic degradation of the southern California desert ecosystem and prospects for natural recovery and restoration  

USGS Publications Warehouse

Large areas of the southern California desert ecosystem have been negatively affected by off-highway vehicle use, overgrazing by domestic livestock, agriculture, urbanization, construction of roads and utility corridors, air pollution, military training exercises, and other activities. Secondary contributions to degradation include the proliferation of exotic plant species and a higher frequency of an- thropogenic fire. Effects of these impacts include alteration or destruction of macro- and micro- vegetation elements, establishment of annual plant communities dominated by exotic species, destruction of soil stabilizers, soil compaction, and increased erosion. Published estimates of recovery time are based on return to predisturbance levels of biomass, cover, density, community structure, or soil characteristics. Natural recovery rates depend on the nature and severity of the impact but are generally very slow. Recovery to predisturbance plant cover and biomass may take 50-300 years, while complete ecosystem recovery may require over 3000 years. Restorative intervention can be used to enhance the success and rate of recovery, but the costs are high and the probability for long-term success is low to moderate. Given the sensitivity of desert habitats to disturbance and the slow rate of natural recovery, the best management option is to limit the extent and intensity of impacts as much as possible.

Lovich, J.E.; Bainbridge, D.

1999-01-01

75

Nine endangered taxa, one recovering ecosystem: Identifying common ground for recovery on Santa Cruz Island, California  

USGS Publications Warehouse

It is not uncommon to have several rare and listed taxa occupying habitats in one landscape or management area where conservation amounts to defense against the possibility of further loss. It is uncommon and extremely exciting, however, to have several listed taxa occupying one island that is managed cooperatively for conservation and recovery. On Santa Cruz Island, the largest of the northern California island group in the Santa Barbara Channel, we have a golden opportunity to marry ecological knowledge and institutional "good will" in a field test of holistic rare plant conservation. Here, the last feral livestock have been removed, active weed control is underway, and management is focused on understanding and demonstrating system response to conservation management. Yet funding limitations still exist and we need to plan the most fiscally conservative and marketable approach to rare plant restoration. We still experience the tension between desirable quick results and the ecological pace of system recovery. Therefore, our research has focused on identifying fundamental constraints on species recovery at individual, demographic, habitat, and ecosystem levels, and then developing suites of actions that might be taken across taxa and landscapes. At the same time, we seek a performance middle ground that balances an institutional need for quick demonstration of hands-on positive results with a contrasting approach that allows ecosystem recovery to facilitate species recovery in the long term. We find that constraints vary across breeding systems, life-histories, and island locations. We take a hybrid approach in which we identify several actions that we can take now to enhance population size or habitat occupancy for some taxa by active restoration, while allowing others to recover at the pace of ecosystem change. We make our recommendations on the basis of data we have collected over the last decade, so that management is firmly grounded in ecological observation.

McEachern, A. Kathryn; Wilken, Dieter H.

2011-01-01

76

Disturbance facilitates the coexistence of antagonistic ecosystem engineers in California estuaries.  

PubMed

Ecological theory predicts that interactions between antagonistic ecosystem engineers can lead to local competitive exclusion, but disturbance can facilitate broader coexistence. However, few empirical studies have tested the potential for disturbance to mediate competition between engineers. We examined the capacity for disturbance and habitat modification to explain the disjunct distributions of two benthic ecosystem engineers, eelgrass Zostera marina and the burrowing ghost shrimp Neotrypaea californiensis, in two California estuaries. Sediment sampling in eelgrass and ghost shrimp patches revealed that ghost shrimp change benthic biogeochemistry over small scales (centimeters) but not patch scales (meters to tens of meters), suggesting a limited capacity for sediment modification to explain species distributions. To determine the relative competitive abilities of engineers, we conducted reciprocal transplantations of ghost shrimp and eelgrass. Local ghost shrimp densities declined rapidly following the addition of eelgrass, and transplanted eelgrass expanded laterally into the surrounding ghost shrimp-dominated areas. When transplanted into eelgrass patches, ghost shrimp failed to persist. Ghost shrimp were also displaced from plots with structural mimics of eelgrass rhizomes and roots, suggesting that autogenic habitat modification by eelgrass is an important mechanism determining ghost shrimp distributions. However, ghost shrimp were able to rapidly colonize experimental disturbances to eelgrass patch edges, which are common in shallow estuaries. We conclude that coexistence in this system is maintained by spatiotemporally asynchronous disturbances and a competition-colonization trade-off: eelgrass is a competitively superior ecosystem engineer, but benthic disturbances permit the coexistence of ghost shrimp at the landscape scale by modulating the availability of space. PMID:25230478

Castorani, Max C N; Hovel, Kevin A; Williams, Susan L; Baskett, Marissa L

2014-08-01

77

Seasonality of the transitional region of the California Current System off Baja California  

NASA Astrophysics Data System (ADS)

Hydrographic data collected over the period 1997-2013 are analyzed to investigate the seasonality of hydrographic features and associated geostrophic flows off the Baja California peninsula. The upper ocean in the region was found to be homogeneous in winter and spring but subdivided into two regions in the summer and autumn. In the first case, the system typically shows relatively low-temperature and salinity waters, which give it a subarctic character. In the second, only the region north of Punta Eugenia (28°N) maintains subarctic characteristics, while the southern region receives an inflow of tropical and subtropical waters that results from the weakening of northwesterly winds, which allows the poleward advection of surface waters. Also during this period, a positive wind stress curl promotes the zonal advection of North Pacific's eastern edge waters into the coast and to the north as a surface coastal flow. Average seasonal patterns of geostrophic flow at 200 dbar revealed that the differentiation into provinces is also evident at that depth, with two clearly defined cyclonic structures in summer and autumn, both separated at the latitude of Punta Eugenia. The analyses conducted also showed a clear continuity of the California undercurrent along the shelf break, with more diffuse currents in the winter. Poleward flows were observed throughout the water column, especially in summer and autumn, although the origin of the surface flow does not necessarily involve a surfacing of the California Undercurrent.

Durazo, Reginaldo

2015-02-01

78

Ecosystems  

NSDL National Science Digital Library

This self-contained module on ecosystems includes a range of fun activities that students can perform in the classroom and at home with family members. They impart important concepts such as observation, identification, measurement, and differentiation.

Houghton Mifflin Science

79

Seasonal dynamics of physical and biological processes in the central California Current System: A modeling study  

NASA Astrophysics Data System (ADS)

A 3-D physical and biological model is used to study the seasonal dynamics of physical and biological processes in the central California Current System. Comparisons of model results with remote sensing and in situ observations along CalCOFI Line 67 indicate our model can capture the spatial variations of key variables (temperature, nutrients, chlorophyll, and so on) on annual mean and seasonal cycle. In the coastal upwelling system, it is the alongshore wind stress that upwells high nutrients to surface from 60 m and stimulates enhanced plankton biomass and productivity in the upwelling season. As a result, coastal species peak in the late upwelling period (May-July), and oceanic species reach the annual maxima in the oceanic period (August-October). The annual maximum occurs in the late upwelling period for new production and in the oceanic period for regenerated production. From the late upwelling period to the oceanic period, stratification is intensified while coastal upwelling becomes weaker. Correspondingly, the coastal ecosystem retreats from ˜300 to ˜100 km offshore with significant decline in chlorophyll and primary production, and the oceanic ecosystem moves onshore. During this transition, the decline in phytoplankton biomass is due to the grazing pressure by mesozooplankton in the 0-150 km domain, but is regulated by low growth rates in the 150-500 km offshore domain. Meanwhile, the growth rates of phytoplankton increase in the coastal waters due to deeper light penetration, while the decrease in offshore growth rates is caused by lower nitrate concentrations.

Guo, Lin; Chai, Fei; Xiu, Peng; Xue, Huijie; Rao, Shivanesh; Liu, Yuguang; Chavez, Francisco P.

2014-08-01

80

The current state of the California biomass energy industry  

SciTech Connect

During the decade of the 1980s the California biomass energy industry grew from a few isolated facilities located mostly at pulp mills into the largest biomass energy industry in the world. Currently, more than fifty biomass powered electricity generating facilities provide the state with some 850 Megawatts (MW) of generating capacity, most of it interconnected to the state`s electric utility systems. Each year, more than ten million tons of wood and agricultural wastes in the state are converted into fuel, rather than being disposed of using conventional, environmentally costly methods like open burning and landfill burial. As the 1980s began, the California biomass energy industry was in a nascent state. Optimism was blooming within the wood-products and agricultural sectors of California, who foresaw an opportunity to turn costly wastes into profits. At the same time, the independent energy industry itself was being launched. Interest in biomass energy development was spreading to the engineering and construction industries and the financial community as well. A great variety of firms and individuals were engaged in the development of biomass power plants and biomass fuel sources. The second half of the 1980s saw the fruits of the developmental activity that began in the first half of the decade. Biomass energy facilities were entering construction and coming on-line in increasing numbers, and the demand for biomass fuels was increasing in step. As the decade was coming to an end, biomass fuel supplies were hard put to meet the demand, yet a huge number of new facilities entered operation in 1990. This extreme growth spurt of new generating capacity caused a fuel crisis and a shake-out in the industry just as it was entering full-scale operation. The Crisis of Success had been reached. More recently an equilibrium has been achieved in which fuel prices are at levels that produce adequate supplies, while allowing profitable operations at the power plants.

Morris, G.P. [Future Resources Associates, Inc., Berkeley, CA (United States)

1994-12-31

81

Observed and Modeled Tsunami Currents on California's North Coast  

NASA Astrophysics Data System (ADS)

In 2009, a pilot project was implemented in Humboldt Bay, near Eureka, California to measure the currents produced by tsunamis. This area is susceptible to both near- and far-field tsunamis and has a historic record of damaging events. Crescent City Harbor, located about 100km north of Humboldt Bay, suffered 20 million in damages from strong currents produced by the 2006 Kuril Islands tsunami and an additional 16 million from the 2011 Tohoku-oki (Japan) tsunami. We deployed a Nortek Aquadopp 600kHz 2D Acoustic Doppler Current Profiler (ADCP) with a one-minute sampling interval in Humboldt Bay, near the NOAA tide gauge site. The instrument recorded the tsunami produced by the Mw 8.8 Chilean earthquake on February 27, 2010 as well as the Mw 9.0 Japanese earthquake on March 11, 2011. Currents from the 2010 tsunami persisted in Humboldt Bay for at least 30hrs with a peak current amplitude of 0.3m/s. The 2011 tsunami signal lasted for over 86hrs with a peak amplitude of 1.2m/s. Strongest currents corresponded to the maximum change in water level as recorded on the NOAA tide gauge, about 90min after the initial wave arrival. Tsunami currents associated with ebb tides (tidal currents flowing out of the bay) were about 25% larger than currents associated with flood tides. No damage was observed in Humboldt Bay for either event; the 2011 tsunami pulled one boat away from its moorings at the marina about six kilometers away from the instrument site. Although we have no instrument in Crescent City, we were able to estimate currents for the first three and a half hours of the Japan tsunami using security camera video footage from the Harbor Master building across from the entrance to the boat basin, about 70m away from the NOAA tide gauge site. Most of the damage occurred within this time window. The strongest currents reached 4.5m/s and six cycles exceeded 4m/s in the three and a half hours of data. We used the MOST (Method of Splitting Tsunamis) model to compare measured currents to numerical predictions. MOST does a reasonably good job of predicting peak amplitudes for the 2010 and 2011 events in Humboldt Bay and the 2011 tsunami in Crescent City. For Humboldt Bay, the model does a good job of replicating the first four hours of the signal although the ebb currents are slightly underestimated. The model predictions break down for the later part of the signal. This project shows that ADCPs can effectively record tsunami currents for small to moderate events. Data from this project will be used to validate and/or calibrate MOST so that realistic tsunami current hazard maps can be generated for California for use by harbor managers.

Admire, A. R.; Dengler, L.; Crawford, G. B.; uslu, B. U.; Montoya, J.; Wilson, R. I.

2011-12-01

82

Assessment: Current & retrospective data on Undergraduates University Library | University of California, Berkeley  

E-print Network

Assessment: Current & retrospective data on Undergraduates University Library | University engines / services" [catalogs? Journal article interfaces?] #12;Assessment: Current & retrospective data;Assessment: Current & retrospective data on Undergraduates University Library | University of California

California at Berkeley, University of

83

Responses of terrestrial ecosystems and carbon budgets to current and future environmental variability  

PubMed Central

We assess the significance of high-frequency variability of environmental parameters (sunlight, precipitation, temperature) for the structure and function of terrestrial ecosystems under current and future climate. We examine the influence of hourly, daily, and monthly variance using the Ecosystem Demography model version 2 in conjunction with the long-term record of carbon fluxes measured at Harvard Forest. We find that fluctuations of sunlight and precipitation are strongly and nonlinearly coupled to ecosystem function, with effects that accumulate through annual and decadal timescales. Increasing variability in sunlight and precipitation leads to lower rates of carbon sequestration and favors broad-leaved deciduous trees over conifers. Temperature variability has only minor impacts by comparison. We also find that projected changes in sunlight and precipitation variability have important implications for carbon storage and ecosystem structure and composition. Based on Intergovernmental Panel on Climate Change model estimates for changes in high-frequency meteorological variability over the next 100 years, we expect that terrestrial ecosystems will be affected by changes in variability almost as much as by changes in mean climate. We conclude that terrestrial ecosystems are highly sensitive to high-frequency meteorological variability, and that accurate knowledge of the statistics of this variability is essential for realistic predictions of ecosystem structure and functioning. PMID:20404190

Medvigy, David; Wofsy, Steven C.; Munger, J. William; Moorcroft, Paul R.

2010-01-01

84

Measurement of Ecosystem Metabolism across Climatic and Vegetation Gradients in California  

NASA Astrophysics Data System (ADS)

Terrestrial ecosystem models require information on vegetation structure, phenology, demographics, biochemistry, radiation properties, and physiology in order to accurately simulate the responses of ecosystem functioning to global change and disturbances. These models generally depend on a small number of intensive, fine-scaled point-based measurements from eddy covariance towers, detailed vegetation surveys, literature values, and site-scale data assimilation techniques to improve model calibration. However, the limited geographic and/or temporal scope of measurements can lead to inadequate model generalizations of modeled carbon (C), water, and energy fluxes across broad regions and relevant time periods. Remote sensing approaches, particularly imaging spectroscopy (IS) and thermal infrared (TIR) data, have the potential to provide the broad-scale spatial and temporal dynamics in many important vegetation properties related to ecosystem functioning. As part of the ongoing NASA HyspIRI Airborne Campaign (http://hyspiri.jpl.nasa.gov/airborne) we are assessing the potential of IS+TIR to generate spatially explicit estimates of two important parameters characterizing plant photosynthetic capacity: the maximum rate of CO2 carboxylation by RuBisCo (Vcmax), and the maximum rate of electron transport required for the regeneration of RuBP needed in Calvin Cycle processes (Jmax). These estimates are based on recent evidence that both properties can be predicted at the leaf level using spectroscopy techniques (Ainsworth et al. 2013 [http://tinyurl.com/n5xnzjg]; Serbin et al. 2012 [http://tinyurl.com/mhocmlz]). It follows that estimation of these variables from remotely sensed IS+TIR (i.e. AVIRIS & MASTER) could facilitate the prediction of seasonal C assimilation across large areas using data from the anticipated HyspIRI satellite mission. Our research focuses on two climate-elevation transects in California, which span a vegetation gradient from coastal sage and chaparral to oak woodlands and closed-canopy coniferous forests, as well as agro-ecosystems located throughout the Central and Imperial Valleys. We are also comparing remotely sensed estimates of ecosystem photosynthetic capacity with C flux data from a series of 10 eddy covariance towers. Results from the 2013 field season highlight the large range in sampled vegetation structure, optical properties (i.e. reflectance and transmittance) and physiology (i.e. Vcmax, Jmax, and cholorphyll fluorescence). Using approaches similar to Serbin et al. (2012) we have confirmed the ability of spectroscopy to estimate Vcmax and Jmax across these diverse and structurally complex vegetation types. Ecosystem products, such as gross primary productivity, estimated from flux towers highlight the relationship between climatic parameters and vegetation productivity. Multiple data-years allow this relationship to be examined under various climatic forcings including drought and heat stress. Based on these preliminary results, our next step is to scale leaf-level information to AVIRIS footprints using radiative transfer and statistical modeling approaches with ecosystem modeling in order to assess the IS data products against flux tower observations.

DuBois, S.; Serbin, S.; Desai, A. R.; Kruger, E.; Kingdon, C.; Goulden, M.; Townsend, P. A.

2013-12-01

85

Current developments in groundwater ecology--from biodiversity to ecosystem function and services.  

PubMed

Groundwater ecosystems constitute the largest terrestrial freshwater biome. They are dark, extremely low in energy and do not provide much space but they contain an unexpectedly high diversity of living forms showing characteristic adaptive features. The restricted accessibility along with the enormous 'invisible' heterogeneity challenged for a long time testing of scientific theories and unraveling of ecosystem functioning. Triggered by an improved interdisciplinarity, comprehensive sampling strategies and current developments in biotechnology and statistical analysis, groundwater ecology gains momentum entering a new era of research. We are only beginning to understand adaptive mechanisms, species distribution patterns and ecosystem functioning. Ninety-five percent of global liquid freshwater is stored in the terrestrial subsurface constituting a major source of water for drinking, irrigation and industrial purposes. There is an urgent need to integrate evolutionary and ecological research for developing a holistic perspective of the functional roles of biodiversity and ecosystem services and predicting global changes under alternative groundwater resource use scenarios. PMID:24590188

Griebler, Christian; Malard, Florian; Lefébure, Tristan

2014-06-01

86

Characterizing conditions of California sage scrub communities in Mediterranean-type ecosystems using remote sensing  

NASA Astrophysics Data System (ADS)

Biodiversity loss is an urgent global issue. For California's Mediterranean-type ecosystems, protecting biologically diverse vegetation communities such as the California sage scrub (CSS) community type is vital to conserving rare, threatened, or endangered species, as well as overall species richness of the southern and Baja California region. While existing monitoring methods such as field surveys and vegetation type mapping provide ecologically valuable information, they do not provide information about internal conditions of CSS communities. Fractional cover of plant life forms is frequently utilized to examine conditions of (semi-)arid vegetation communities. For the CSS community type, however, the utility of life-form fractional cover has not received adequate attention as an effective monitoring variable indicating ecological integrity; thus, no reliable, cost-effective methods have been developed. This dissertation investigates the effectiveness of fractional cover of true shrub, subshrub, herb, and bare ground for quantifying CSS community conditions, tests remote sensing approaches to obtain spatially comprehensive life-form cover fractions, and explores the utility of life-form fractional cover maps for sustainable, effective long-term monitoring of CSS communities of southern California. Past studies indicate that fractional cover of plant life forms is an effective measure for quantifying CSS community integrity, and remote sensing is the only means to estimate spatially exhaustive cover fractions cost-effectively over large extent. Among the remote sensing approaches tested, object-based image analysis using pansharpened QuickBird imagery shows the most promise for estimating life-form fractional cover within CSS communities because of its high accuracy (e.g., RMSE as low as 6.4%) and robustness in estimating cover fractions and ability of providing life-form-level landscape metrics. Multiple Endmember Spectral Mixture Analysis using SPOT imagery is capable of estimating cover fractions with comparable accuracy and is beneficial for retrospective analysis for life-form cover changes and cost-effective ecological monitoring. Using spatially exhaustive life-form cover fractions, maps indicating CSS community conditions and species' life-form cover preference were generated. Such maps can fill information gaps between field-based data and vegetation type maps and provide valuable information about habitat recovery, habitat suitability, and ecological integrity of CSS communities. By combining these methods, more effective CSS community monitoring can be achieved.

Hamada, Yuki

87

Effects of Management on Soil Carbon Pools in California Rangeland Ecosystems  

NASA Astrophysics Data System (ADS)

Rangeland ecosystems managed for livestock production represent the largest land-use footprint globally, covering more than one-quarter of the world's land surface (Asner et al. 2004). In California, rangelands cover an estimated 17 million hectares or approximately 40% of the land area (FRAP 2003). These ecosystems have considerable potential to sequester carbon (C) in soil and offset greenhouse gas emissions through changes in land management practices. Climate policies and C markets may provide incentives for rangeland managers to pursue strategies that optimize soil C storage, yet we lack a thorough understanding of the effects of management on soil C pools in rangelands over time and space. We sampled soil C pools on rangelands in a 260 km2 region of Marin and Sonoma counties to determine if patterns in soil C storage exist with management. Replicate soil samples were collected from 35 fields that spanned the dominant soil orders, plant communities, and management practices in the region while controlling for slope and bioclimatic zone (n = 1050). Management practices included organic amendments, intensive (dairy) and extensive (other) grazing practices, and subsoiling. Soil C pools ranged from approximately 50 to 140 Mg C ha-1 to 1 m depth, with a mean of 99 ± 22 (sd) Mg C ha-1. Differences among sites were due primarily to C concentrations, which exhibited a much larger coefficient of variation than bulk density at all depths. There were no statistically significant differences among the dominant soil orders. Subsoiling appeared to significantly increase soil C content in the top 50 cm, even though subsoiling had only occurred for the first time the previous Nov. Organic amendments also appeared to greatly increase soil C pools, and was the dominant factor that distinguished soil C pools in intensive and extensive land uses. Our results indicate that management has the potential to significantly increase soil C pools. Future research will determine the location of sequestered C within the soil matrix and its turnover time.

Silver, W. L.; Ryals, R.; Lewis, D. J.; Creque, J.; Wacker, M.; Larson, S.

2008-12-01

88

Ecosystems  

NSDL National Science Digital Library

This "Ecosystems" module has four units of instruction. The units include: natural selection, population balance, exchange cycles, and environmental protection. Each module has a "Hazards" link that leads to a menu of study units on various environmental hazards (such as oil spills, farm runoff, insecticides, and so on).

W. R. Klemm

2002-01-01

89

Fire and aquatic ecosystems of the western USA: Current knowledge and key questions  

USGS Publications Warehouse

Understanding of the effects of wildland fire and fire management on aquatic and riparian ecosystems is an evolving field, with many questions still to be resolved. Limitations of current knowledge, and the certainty that fire management will continue, underscore the need to summarize available information. Integrating fire and fuels management with aquatic ecosystem conservation begins with recognizing that terrestrial and aquatic ecosystems are linked and dynamic, and that fire can play a critical role in maintaining aquatic ecological diversity. To protect aquatic ecosystems we argue that it will be important to: (1) accommodate fire-related and other ecological processes that maintain aquatic habitats and biodiversity, and not simply control fires or fuels; (2) prioritize projects according to risks and opportunities for fire control and the protection of aquatic ecosystems; and (3) develop new consistency in the management and regulatory process. Ultimately, all natural resource management is uncertain; the role of science is to apply experimental design and hypothesis testing to management applications that affect fire and aquatic ecosystems. Policy-makers and the public will benefit from an expanded appreciation of fire ecology that enables them to implement watershed management projects as experiments with hypothesized outcomes, adequate controls, and replication.

Bisson, P.A.; Rieman, B.; Luce, C.; Hessburg, P.F.; Lee, D.; Kershner, J.; Reeves, G.H.; Gresswell, Robert E.

2003-01-01

90

Identifying Key Vulnerabilities in Current Management of California Central Valley for the California Water Plan  

NASA Astrophysics Data System (ADS)

The California Department of Water Resources (DWR), for its 2013 Update of the California Water Plan (CWP), is building new analytic capabilities for developing and evaluating regional and state-wide water management strategies. These strategies are intended to address growing and diverse water needs coupled with uncertain future hydrologic conditions and available supplies. Recognizing the significant uncertainty about future water management conditions, DWR is utilizing new robust decision methods to identify robust and adaptive water management strategies. This talk will describe a recently completed application of Robust Decision Making (RDM) for long-term water planning as part of the 2013 CWP Update. This analysis utilizes a new hydrologic / water management model of the Sacramento River, San Joaquin River, and Tulare hydrologic regions, running the model under hundreds of potential futures. These futures consider potential variation in demographic growth, land-use patterns, drought length and timing, and other climate factors from projections generated by downscaled global circulation models. Cluster-finding "scenario discovery" algorithms, applied to the resulting database of simulation model results, identify the key characteristics of future conditions where current management fails to meet a wide range of policy objectives. These "vulnerabilities" provide the foundation for developing more robust and adaptive response packages and the considering tradeoffs between such response packages. This analysis will provide guidance for considering response packages to meet the challenges posed by future conditions in the California Central Valley and provides a widely applicable new approach for making water management plans more cognizant and responsive to a wide range of uncertainties.

Bloom, E.; Groves, D.; Joyce, B. A.; Juricich, R.

2012-12-01

91

Effects of Climate Change on Sardine Productivity in the California Current System  

NASA Astrophysics Data System (ADS)

The Pacific sardine (Sardinops sagax caeruleus) is one of several coastal pelagic, planktivorous species of fish that provide important trophic links within the ecosystems of the major eastern and western boundary currents. Significant and persistent change in sardine productivity has occurred in the California Current over interdecadal periods in response to reorganization of basin-wide, ocean-atmosphere circulation. Less extreme, but still significant changes in sardine productivity are associated with interannual to decadal-scale climate variability. A precipitous decline of the sardine population began in the mid-1940s with a shift in climate leading to cooling of the California Current system. While the decline, and ultimately the collapse of the population, was exacerbated by intensive fishing, the sardine also suffered a severe reduction in productivity with the southward contraction of favorable thermal habitat that led to restriction of the population to the waters off Southern California and Baja California. This southward displacement resulted in geographic separation of the population from the region off central and northern California that is characterized by significantly higher concentrations of zooplankton that supported the previous levels of success in spawning and larval development. The climate shift in 1976-77 led to the recovery of the population and extension of its range of distribution northwards into the waters off British Columbia. The relation of reproductive success of the sardine population to interannual and decadal climate change was examined for the period 1982-2005 using a suite of seasonal indices representing climate processes and habitat conditions (including zooplankton food levels) occurring through the different stages in the sardine life cycle. We used both stepwise regression and EOF analyses to determine the association between levels of recruitment success and seasonal indices of the Pacific Decadal Oscillation, Ekman pumping (measured at 35°N, 122.5°W), coastal upwelling (at 36°N, 122°W) and zooplankton biomass (represented by values from the center of sardine spawning). The seasonal indices of the PDO are positively correlated with reproductive success, while an inverse relationship between the PDO indices and coastal upwelling is consistent with reduced equatorward flow during coastal warming that favors sardine reproduction. Results also show an unambiguous inverse relationship between Ekman pumping and sardine recruitment success indicating the negative influence of increased offshore transport on the survival of eggs and larvae. There is a surprising lack of association between recruitment success and zooplankton biomass, interpreted to mean that food was not limiting for sardine reproduction during the period analyzed (in the warm regime after 1977). Based on the results of this study, we anticipate that global warming will favor the maintenance of the sardine population over its present range from the Gulf of California into the waters of British Columbia throughout the current century.

Baumgartner, T. R.; Auad, G.; Miller, A. J.

2007-05-01

92

Modeling Hawaiian ecosystem degradation due to invasive plants under current and future climates.  

PubMed

Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with <0.7 niche overlap (Warrens I) and relatively discriminative distributions (Area Under the Curve >0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions. PMID:24805254

Vorsino, Adam E; Fortini, Lucas B; Amidon, Fred A; Miller, Stephen E; Jacobi, James D; Price, Jonathan P; Gon, Sam 'ohukani'ohi'a; Koob, Gregory A

2014-01-01

93

Modeling Hawaiian Ecosystem Degradation due to Invasive Plants under Current and Future Climates  

PubMed Central

Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with <0.7 niche overlap (Warrens I) and relatively discriminative distributions (Area Under the Curve >0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions. PMID:24805254

Vorsino, Adam E.; Fortini, Lucas B.; Amidon, Fred A.; Miller, Stephen E.; Jacobi, James D.; Price, Jonathan P.; Gon, Sam 'Ohukani'ohi'a; Koob, Gregory A.

2014-01-01

94

DDT RESIDUES IN SEAWATER AND PARTICULATE MATTER IN THE CALIFORNIA CURRENT SYSTEM  

E-print Network

DDT RESIDUES IN SEAWATER AND PARTICULATE MATTER IN THE CALIFORNIA CURRENT SYSTEM JAMES L. COX in the California current system were analyzed for DDT residues. DDT residue concentrations in whole seawater are discussed in relation to mechanisms of land-sea DDT residue transfer. DDT residue concentrations

95

The California Current system: The seasonal variability of its physical characteristics  

Microsoft Academic Search

The seasonal variation of the physical characteristics and of large-scale current patterns of the California Current system is examined using harmonic analysis applied to the 23 years of California cooperative Oceanic Fisheries Investigations data collected between 1950 and 1978. The amplitude and phasing of seasonal variation in dynamic height and the overall standard deviation of dynamic height define three domains:

Ronald J. Lynn; James J. Simpson

1987-01-01

96

Current Development at the Southern California Earthquake Data Center (SCEDC)  

NASA Astrophysics Data System (ADS)

Over the past year, the SCEDC completed or is near completion of three featured projects: Station Information System (SIS) Development: The SIS will provide users with an interface into complete and accurate station metadata for all current and historic data at the SCEDC. The goal of this project is to develop a system that can interact with a single database source to enter, update and retrieve station metadata easily and efficiently. The system will provide accurate station/channel information for active stations to the SCSN real-time processing system, as will as station/channel information for stations that have parametric data at the SCEDC i.e., for users retrieving data via STP. Additionally, the SIS will supply information required to generate dataless SEED and COSMOS V0 volumes and allow stations to be added to the system with a minimum, but incomplete set of information using predefined defaults that can be easily updated as more information becomes available. Finally, the system will facilitate statewide metadata exchange for both real-time processing and provide a common approach to CISN historic station metadata. Moment Tensor Solutions: The SCEDC is currently archiving and delivering Moment Magnitudes and Moment Tensor Solutions (MTS) produced by the SCSN in real-time and post-processing solutions for events spanning back to 1999. The automatic MTS runs on all local events with magnitudes > 3.0, and all regional events > 3.5. The distributed solution automatically creates links from all USGS Simpson Maps to a text e-mail summary solution, creates a .gif image of the solution, and updates the moment tensor database tables at the SCEDC. Searchable Scanned Waveforms Site: The Caltech Seismological Lab has made available 12,223 scanned images of pre-digital analog recordings of major earthquakes recorded in Southern California between 1962 and 1992 at http://www.data.scec.org/research/scans/. The SCEDC has developed a searchable web interface that allows users to search the available files, select multiple files for download and then retrieve a zipped file containing the results. Scanned images of paper records for M>3.5 southern California earthquakes and several significant teleseisms are available for download via the SCEDC through this search tool.

Appel, V. L.; Clayton, R. W.

2005-12-01

97

Sierra Nevada Ecosystem Project: Final report to Congress, vol. III, Assessments and scientific basis for management options. Davis: University of California, Centers for Water and Wildland Resources, 1996.  

E-print Network

Sierra Nevada Ecosystem Project: Final report to Congress, vol. III, Assessments and scientific, 1996. ROLAND A. KNAPP Sierra Nevada Aquatic University of California Mammoth Lakes, California Lakes of the Sierra Nevada: An Analysis of Their Distribution and Impacts on Native Aquatic Biota Back

Knapp, Roland

98

Integrated Carbon Observation System (ICOS) ecosystem network: current state and future perspectives  

NASA Astrophysics Data System (ADS)

Atmospheric concentrations of greenhouse gases (GHG) such as carbon dioxide (CO2) and methane (CH4) are increasing due to emissions related to human activity, affecting the global climate. Natural sinks remove a fraction of the GHG anthropogenic excess at the global level. The characterization of greenhouse gases atmospheric burden and fluxes, both anthropogenic and natural, are needed at the global and regional scale, making use of all available information in an integrated framework. The Integrated Carbon Observation System (ICOS) research infrastructure will address this issue by providing the community with systematic measurements of a suite of atmospheric, terrestrial ecosystem and oceanic measurements. The ecosystem network comprises three station classes, for which variables are collected with different intensity. These stations are well distributed among the major European ecosystem types and cover most climatic zones in Europe. The Ecosystem Thematic Center (ETC) is coordinating the ICOS ecosystem network providing assistance with instruments and methods, testing and developing new measurement techniques and associated processing algorithms; also ensuring a high level of data standardization, uncertainty analysis and database services in coordination with the ICOS carbon portal. The ETC is also coordinating the drafting of the protocols describing in detail how measurements will be collected at all ecosystem stations, in order to guarantee inter comparability. This is done in close collaboration with experts in the field and with the other existing ecological and meteorological networks (NEON, Ameriflux, ICP -forests, MWO, TERN, ...). This presentation will focus on the current state of the ICOS ecosystem network, on the data products and the potential user community.

Gielen, B.; Op de Beeck, M.; Ceulemans, R.; Janssens, I.; Loustau, D.; Valentini, R.; Papale, D.

2013-12-01

99

Cumulative Human Impacts on Mediterranean and Black Sea Marine Ecosystems: Assessing Current Pressures and Opportunities  

PubMed Central

Management of marine ecosystems requires spatial information on current impacts. In several marine regions, including the Mediterranean and Black Sea, legal mandates and agreements to implement ecosystem-based management and spatial plans provide new opportunities to balance uses and protection of marine ecosystems. Analyses of the intensity and distribution of cumulative impacts of human activities directly connected to the ecological goals of these policy efforts are critically needed. Quantification and mapping of the cumulative impact of 22 drivers to 17 marine ecosystems reveals that 20% of the entire basin and 60–99% of the territorial waters of EU member states are heavily impacted, with high human impact occurring in all ecoregions and territorial waters. Less than 1% of these regions are relatively unaffected. This high impact results from multiple drivers, rather than one individual use or stressor, with climatic drivers (increasing temperature and UV, and acidification), demersal fishing, ship traffic, and, in coastal areas, pollution from land accounting for a majority of cumulative impacts. These results show that coordinated management of key areas and activities could significantly improve the condition of these marine ecosystems. PMID:24324585

Micheli, Fiorenza; Halpern, Benjamin S.; Walbridge, Shaun; Ciriaco, Saul; Ferretti, Francesco; Fraschetti, Simonetta; Lewison, Rebecca; Nykjaer, Leo; Rosenberg, Andrew A.

2013-01-01

100

Parallel adjustments in vegetation greenness and ecosystem CO 2 exchange in response to drought in a Southern California chaparral ecosystem  

Microsoft Academic Search

Some form of the light use efficiency (LUE) model is used in most models of ecosystem carbon exchange based on remote sensing. The strong relationship between the normalized difference vegetation index (NDVI) and light absorbed by green vegetation make models based on LUE attractive in the remote sensing context. However, estimation of LUE has proven problematic since it varies with

Daniel A. Sims; Hongyan Luo; Steven Hastings; Walter C. Oechel; Abdullah F. Rahman; John A. Gamon

2006-01-01

101

Indirect effects of conservation policies on the coupled human-natural ecosystem of the upper Gulf of California.  

PubMed

High bycatch of non-target species and species of conservation concern often drives the implementation of fisheries policies. However, species- or fishery-specific policies may lead to indirect consequences, positive or negative, for other species or fisheries. We use an Atlantis ecosystem model of the Northern Gulf of California to evaluate the effects of fisheries policies directed at reducing bycatch of vaquita (Phocoena sinus) on other species of conservation concern, priority target species, and metrics of ecosystem function and structure. Vaquita, a Critically Endangered porpoise endemic to the Upper Gulf of California, are frequently entangled by finfish gillnets and shrimp driftnets. We tested five fishery management scenarios, projected over 30 years (2008 to 2038), directed at vaquita conservation. The scenarios consider progressively larger spatial restrictions for finfish gillnets and shrimp driftnets. The most restrictive scenario resulted in the highest biomass of species of conservation concern; the scenario without any conservation measures in place resulted in the lowest. Vaquita experienced the largest population increase of any functional group; their biomass increased 2.7 times relative to initial (2008) levels under the most restrictive spatial closure scenario. Bycatch of sea lions, sea turtles, and totoaba decreased > 80% in shrimp driftnets and at least 20% in finfish gillnet fleets under spatial management. We found indirect effects on species and ecosystem function and structure as a result of vaquita management actions. Biomass and catch of forage fish declined, which could affect lower-trophic level fisheries, while other species such as skates, rays, and sharks increased in both biomass and catch. When comparing across performance metrics, we found that scenarios that increased ecosystem function and structure resulted in lower economic performance indicators, underscoring the need for management actions that consider ecological and economic tradeoffs as part of the integrated management of the Upper Gulf of California. PMID:23691155

Morzaria-Luna, Hem Nalini; Ainsworth, Cameron H; Kaplan, Isaac C; Levin, Phillip S; Fulton, Elizabeth A

2013-01-01

102

Indirect Effects of Conservation Policies on the Coupled Human-Natural Ecosystem of the Upper Gulf of California  

PubMed Central

High bycatch of non-target species and species of conservation concern often drives the implementation of fisheries policies. However, species- or fishery-specific policies may lead to indirect consequences, positive or negative, for other species or fisheries. We use an Atlantis ecosystem model of the Northern Gulf of California to evaluate the effects of fisheries policies directed at reducing bycatch of vaquita (Phocoena sinus) on other species of conservation concern, priority target species, and metrics of ecosystem function and structure. Vaquita, a Critically Endangered porpoise endemic to the Upper Gulf of California, are frequently entangled by finfish gillnets and shrimp driftnets. We tested five fishery management scenarios, projected over 30 years (2008 to 2038), directed at vaquita conservation. The scenarios consider progressively larger spatial restrictions for finfish gillnets and shrimp driftnets. The most restrictive scenario resulted in the highest biomass of species of conservation concern; the scenario without any conservation measures in place resulted in the lowest. Vaquita experienced the largest population increase of any functional group; their biomass increased 2.7 times relative to initial (2008) levels under the most restrictive spatial closure scenario. Bycatch of sea lions, sea turtles, and totoaba decreased > 80% in shrimp driftnets and at least 20% in finfish gillnet fleets under spatial management. We found indirect effects on species and ecosystem function and structure as a result of vaquita management actions. Biomass and catch of forage fish declined, which could affect lower-trophic level fisheries, while other species such as skates, rays, and sharks increased in both biomass and catch. When comparing across performance metrics, we found that scenarios that increased ecosystem function and structure resulted in lower economic performance indicators, underscoring the need for management actions that consider ecological and economic tradeoffs as part of the integrated management of the Upper Gulf of California. PMID:23691155

Morzaria-Luna, Hem Nalini; Ainsworth, Cameron H.; Kaplan, Isaac C.; Levin, Phillip S.; Fulton, Elizabeth A.

2013-01-01

103

Foraging ecology and movement patterns of jumbo squid (Dosidicus gigas) in the California Current System  

NASA Astrophysics Data System (ADS)

From 2002 to 2010, the jumbo squid (Dosidicus gigas) has been regularly encountered in large numbers throughout the California Current System (CCS). This species, usually found in subtropical waters, could affect coastal pelagic ecosystems and fisheries as both predator and prey. Neither the abundance of jumbo squid nor the optimal ocean conditions in which they flourish are well known. To understand better the potential impacts of this species on both commercial fisheries and on food-web structure we collected nearly 900 specimens from waters of the CCS, covering over 20° of latitude, over a range of depths and seasons. We used demographic information (size, sex, and maturity state) and analyzed stomach contents using morphological and molecular methods to best understand the foraging ecology of this species in different habitats of the CCS. Squid were found to consume a broad array of prey. Prey in offshore waters generally reflected the forage base reported in previous studies (mainly mesopelagic fishes and squids), whereas in more coastal waters (shelf, shelf break and slope habitats) squid foraged on a much broader mix that included substantial numbers of coastal pelagic fishes (Pacific herring and northern anchovy, as well as osmerids and salmonids in northern waters) and groundfish (Pacific hake, several species of rockfish and flatfish). We propose a seasonal movement pattern, based on size and maturity distributions along with qualitative patterns of presence or absence, and discuss the relevance of both the movement and distribution of jumbo squid over space and time. We find that jumbo squid are a generalist predator, which feeds primarily on small, pelagic or mesopelagic micronekton but also on larger fishes when they are available. We also conclude that interactions with and potential impacts on ecosystems likely vary over space and time, in response to both seasonal movement patterns and highly variable year-to-year abundance of the squid themselves.

Field, John C.; Elliger, Carl; Baltz, Ken; Gillespie, Graham E.; Gilly, William F.; Ruiz-Cooley, R. I.; Pearse, Devon; Stewart, Julia S.; Matsubu, William; Walker, William A.

2013-10-01

104

Microbial Enzymatic Response to Reduced Precipitation and Added Nitrogen in a Southern California Grassland Ecosystem  

NASA Astrophysics Data System (ADS)

Microbial enzymes play a fundamental role in ecosystem processes and nutrient mineralization. Although there have been many studies concluding that global climate change affects plant communities, the effects on microbial communities in leaf litter have been much less studied. We measured extracellular enzyme activities in litter decomposing in plots with either reduced precipitation or increased nitrogen in a grassland ecosystem in Loma Ridge National Landmark in Southern California. We used a reciprocal transplant design to examine the effects of plot treatment, litter origin, and microbial community origin on litter decomposition and extracellular enzyme activity. Our hypothesis was that increased nitrogen would increase activity because nitrogen often limits microbial growth, while decreased precipitation would decrease activity due to lower litter moisture levels. Samples were collected in March 2011 and analyzed for the activities of cellobiohydrolase (CBH), ?-glucosidase (BG), ?-glucosidase (AG), N-acetyl-?-D-glucosaminidase (NAG), ?-xylosidase (BX), acid phosphatase (AP), and leucine aminopeptidase (LAP). None of the factors in the nitrogen manipulation had a significant effect on any of the enzymes, although BG, CBH, and NAG increased marginally significantly in plots with nitrogen addition (p = 0.103, p = 0.082, and p = 0.114, respectively). For the precipitation manipulation, AG, BG, BX, CBH, and NAG significantly increased in plots with reduced precipitation (p = 0.015, p <0.001, p<0.001, and p<0.001, respectively) while LAP significantly decreased (p = 0.002). LAP catalyzes the hydrolysis of polypeptides, so reduced LAP activity could result in lower rates of enzyme turnover in the reduced precipitation treatment. We also observed that AP significantly increased (p = 0.014) in litter originating from reduced precipitation plots, while AG, BX, and LAP significantly decreased (p = 0.011, p = 0.031, and 0.005, respectively). There were no significant correlations found between fungal or bacterial mass and enzymatic activity with either of the treatment types. Our results suggest that increased enzymatic activity due to drought could mitigate negative effects of moisture limitation on decomposition. However, this mitigating effect may be offset by declines in enzyme activity due to changes in plant community composition and associated litter chemistry in response to drought.

Alster, C. J.; German, D.; Allison, S. D.

2011-12-01

105

Winter pre-conditioning of seabird phenology in the California Current  

Microsoft Academic Search

Climate change is predicted to affect the phasing and amplitude of upwelling in eastern boundary current marine ecosystems. Effects may be strongest during the spring or summer 'upwelling season,' but may also be influential during winter before the spring transition. We tested the hypothesis that wintertime environmental forcing 'pre-conditions' the ecosystem and affects the timing and success of breeding in

Isaac D. Schroeder; William J. Sydeman; Nandita Sarkar; Sarah Ann Thompson; Steven J. Bograd; Franklin B. Schwing

2009-01-01

106

CURRENT BREEDING STATUS OF THE YELLOW HEADED BLACKBIRD IN CALIFORNIA  

Microsoft Academic Search

of 1971,we also recorded observations on Yellow-headed Blackbirds (Xanthocephalus xanthocephalus). These observations are reported here and compared with published information on the historical breeding status of Yellow-headed Blackbirds in California. Regions containing potential breeding habitat for blackbirds were identified from topographic maps and systematically searched during the breeding season. Over 8,000 miles were driven within California between 23 April and

Frederick T. Crase; Richard W. DeHaven

1972-01-01

107

A numerical study of stochastic larval settlement in the California Current system  

NASA Astrophysics Data System (ADS)

Key to the predictive understanding of many nearshore marine ecosystems is the transport of larvae by ocean circulation processes. Many species release thousands to billions of larvae to develop in pelagic waters, but only a few lucky ones successfully settle to suitable habitat and recruit to adult life stages. Methodologies for predicting the larval dispersal are still primitive, and simple diffusive analyses are still used for many important applications. In this study, we investigate mechanisms of larval dispersal using idealized simulations of time-evolving coastal circulations in the California Current system with Lagrangian particles as models for planktonic larvae. Connectivity matrices, which describe the source-to-destination relationships for larval dispersal for a given larval development time course, are used to diagnose the time-space dynamics of larval settlement. The resulting connectivity matrices are shown to be a function of several important time scales, such as the planktonic larval duration, the frequency and duration of larval release events and inherent time scales for the coastal circulations. Many important fishery management applications require knowledge of fish stocks on a year-to-year or generation-to-generation basis. For these short time scales (typically less than 1 year), larval dispersal is generally far from a simple diffusive process and the consideration of the stochastic and episodic nature of larval dispersal is required. This work provides new insights into the spatial-temporal dynamics of nearshore fish stocks.

Mitarai, S.; Siegel, D. A.; Winters, K. B.

108

Processes influencing seasonal hypoxia in the northern California Current System  

PubMed Central

This paper delineates the role of physical and biological processes contributing to hypoxia, dissolved oxygen (DO) < 1.4 mL/L, over the continental shelf of Washington State in the northern portion of the California Current System (CCS). In the historical record (1950–1986) during the summer upwelling season, hypoxia is more prevalent and severe off Washington than further south off northern Oregon. Recent data (2003–2005) show that hypoxia over the Washington shelf occurred at levels previously observed in the historical data. 2006 was an exception, with hypoxia covering ~5000 km2 of the Washington continental shelf and DO concentrations below 0.5 mL/L at the inner shelf, lower than any known previous observations at that location. In the four years studied, upwelling of low DO water and changes in source water contribute to interannual variability, but cannot account for seasonal decreases below hypoxic concentrations. Deficits of DO along salinity surfaces, indicating biochemical consumption of DO, vary significantly between surveys, accounting for additional decreases of 0.5–2.5 mL/L by late summer. DO consumption is associated with denitrification, an indicator of biochemical sediment processes. Mass balances of DO and nitrate show that biochemical processes in the water column and sediments each contribute ~50% to the total consumption of DO in near-bottom water. At shorter than seasonal time scales on the inner shelf, along-shelf advection of hypoxic patches and cross-shelf advection of seasonal gradients are both shown to be important, changing DO concentrations by 1.5 mL/L or more over five days. PMID:20463844

Connolly, T. P.; Hickey, B. M.; Geier, S. L.; Cochlan, W. P.

2010-01-01

109

PATCHINESS AND NUTRITIONAL CONDITION OF ZOOPLANKmN IN THE CALIFORNIA CURRENT  

E-print Network

:tIc.lls near Point Conception and south of San Francisco in comparison to animals in other parts of the California Current suggest that animals in these areas experience pro- longed periods of better nutrition California coast Results of measurements of temperature, phyto- plankton biomass, zooplankton abundance

110

Changing sources and sinks of carbon in boreal ecosystems of Interior Alaska: Current and future perspectives  

NASA Astrophysics Data System (ADS)

Future climate scenarios predict a roughly 5°C increase in mean annual air temperatures for the Alaskan Interior over the next 80 years. Increasing temperatures and greater frequency and severity of climate-induced disturbances such as wildfires will be enough to initiate permafrost degradation in many areas of Alaska, leading to major changes in surface hydrology and ecosystem structure and function. This, in turn, is expected to alter the current inventories of carbon sources and sinks in the region and provide a management challenge for carbon itemization efforts. To assist land managers in adapting and planning for potential changes in Interior Alaska carbon cycling we synthesize information on climate, ecosystem processes, vegetation, and soil, permafrost, and hydrologic regimes in Interior Alaska. Our goal is to provide an assessment of the current and likely future regime of Interior Alaska carbon sources and sinks. For our carbon assessment we: 1) synthesize the most recent results from numerous studies on the carbon cycle with a focus on research from the Alaskan boreal biome, 2) assemble a summary of estimates of carbon sources in soil and vegetation in Interior Alaska, 3) categorize carbon sources and sinks for predominant Interior Alaska ecosystems, and 4) identify expected changes in sources and sinks with climate change and human activities. This information is used to provide recommendations on potential actions land managers can take to minimize carbon export from the boreal forest. Though the results from our project are geared primarily toward policy makers and land managers we also provide recommendations for filling research gaps that currently present uncertainty in our understanding of the carbon cycle in boreal forest ecosystems of Interior Alaska.

Douglas, T. A.; Jones, M.; Hiemstra, C. A.

2012-12-01

111

SAFRR tsunami scenario: impacts on California ecosystems, species, marine natural resources, and fisheries: Chapter G in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario  

USGS Publications Warehouse

We evaluate the effects of the SAFRR Tsunami Scenario on California’s ecosystems, species, natural resources, and fisheries. We discuss mitigation and preparedness approaches that can be useful in Tsunami planning. The chapter provides an introduction to the role of ecosystems and natural resources in tsunami events (Section 1). A separate section focuses on specific impacts of the SAFRR Tsunami Scenario on California’s ecosystems and endangered species (Section 2). A section on commercial fisheries and the fishing fleet (Section 3) documents the plausible effects on California’s commercial fishery resources, fishing fleets, and communities. Sections 2 and 3 each include practical preparedness options for communities and suggestions on information needs or research. Our evaluation indicates that many low-lying coastal habitats, including beaches, marshes and sloughs, rivers and waterways connected to the sea, as well as nearshore submarine habitats will be damaged by the SAFRR Tsunami Scenario. Beach erosion and complex or high volumes of tsunami-generated debris would pose major challenges for ecological communities. Several endangered species and protected areas are at risk. Commercial fisheries and fishing fleets will be affected directly by the tsunami and indirectly by dependencies on infrastructure that is damaged. There is evidence that in some areas intact ecosystems, notably sand dunes, will act as natural defenses against the tsunami waves. However, ecosystems do not provide blanket protection against tsunami surge. The consequences of ecological and natural resource damage are estimated in the millions of dollars. These costs are driven partly by the loss of ecosystem services, as well as cumulative and follow-on impacts where, for example, increased erosion during the tsunami can in turn lead to subsequent damage and loss to coastal properties. Recovery of ecosystems, natural resources and fisheries is likely to be lengthy and expensive. Preparedness is key to enhancing resilience to ecological impacts.

Brosnan, Deborah; Wein, Anne; Wilson, Rick

2014-01-01

112

Benthic production and processes off Baja California, northwest Africa and Peru: a classification of benthic subsystems in upwelling ecosystems  

SciTech Connect

Estimates of the standing stocks, secondary production and metabolism of the benthos have been compared in the coastal upwelling ecosystems off northwest Africa, Baja California, and southern Peru. Northwest Africa is characterized by shelf break upwelling and as a result standing stocks, macrobenthic production and sediment organic matter are highest out at the shelf-slope boundary. Sediment microbial activity and biomass on the other hand are highest nearshore in the dynamic zone where aeolian silt and sand are being blown into the sea from the Sahara Desert. Baja California is dominated by the red crab, Pleuroncodes planipes, having high rates of growth and metabolic utilization of organic matter, both on bottom and in the water. Peru benthos and metabolism are very different from the above areas because of the low oxygen concentrations in the bottom water. Organic matter is far higher in the sediment and heterotrophic metabolism is principally anaerobic rather than aerobic. A normal offshore benthic fauna is replaced by a mat of sulfur bacteria with unknown production and metabolic rates. Benthic subsystems in upwelling ecosystems can be placed in two categories: those overloaded with organic matter, depleted of oxygen and dominated by sulfate reduction and those that are not overloaded and remain aerobic. Peru and southwest Africa typify overloaded systems whereas NW Africa and Baja California are examples of aerobic systems. Although benthic metabolism and ionorganic nutrient regeneration are high in both types of subsystems, all upwelling ecosystems, with their dynamic open boundaries, export organic particulate matter and import inorganic nutrients at rates that are far in excess of that consumed or produced by benthic metabolism. 42 refs., 7 figs., 8 tabs.

Rowe, G.T.

1983-01-01

113

Integrated biochemical, molecular genetic, and bioacoustical analysis of mesoscale variability of the euphausiid Nematoscelis difficilis in the California Current  

NASA Astrophysics Data System (ADS)

Integrated assessment of the euphausiid Nematoscelis difficilis (Crustacea; Euphausiacea) and the zooplankton assemblage of the California Current was designed to investigate individual, population, and community responses to mesoscale variability in biological and physical characters of the ocean. Zooplankton samples and observational data were collected along a cross-shelf transect of the California Current in association with the California Cooperative Fisheries Investigations (CalCOFI) Survey during October 1996. The transect crossed three domains defined by temperature and salinity: nearshore, mid-Current, and offshore. Individual N. difficilis differed in physiological condition along the transect, with higher size-corrected concentrations of four central metabolic enzymes (citrate synthetase, hexokinase, lactate dehydrogenase (LDH), and phosphoglucose isomerase (PGI)) for euphausiids collected in nearshore waters than in mid-Current and offshore waters. There was little variation in the DNA sequences of the genes encoding PGI and LDH (all DNA changes were either silent or heterozygous base substitutions), suggesting that differences in enzyme concentration did not result from underlying molecular genetic variation. The population genetic makeup of N. difficilis varied from sample to sample based on haplotype frequencies of mitochondrial cytochrome oxidase I (mtCOI; P=0.029). There were significant differences between pooled nearshore and offshore samples, based on allele frequencies at two sites of common substitutions in the mtCOI sequence ( P=0.020 and 0.026). Silhouette and bioacoustical backscattering measurements of the zooplankton assemblage of the top 100 m showed marked diel vertical migration of the scattering layer, of which euphausiids were a small but significant fraction. The biochemical and molecular assays are used as indices of complex physiological (i.e., growth and condition) and genetic (i.e., mortality) processes; the bioacoustical observations provide insight into the ecosystem context for the single-species measurements. All data are intended for integration into predictive models of secondary production and biomass concentration in the ocean.

Bucklin, Ann; Wiebe, Peter H.; Smolenack, Sara B.; Copley, Nancy J.; Clarke, M. Elizabeth

2002-03-01

114

Effects of Debris Flows on Stream Ecosystems of the Klamath Mountains, Northern California  

NASA Astrophysics Data System (ADS)

We examined the long-term effects of debris flows on channel characteristics and aquatic food webs in steep (0.04-0.06 slope), small (4-6 m wide) streams. A large rain-on-snow storm event in January 1997 resulted in numerous landslides and debris flows throughout many basins in the Klamath Mountains of northern California. Debris floods resulted in extensive impacts throughout entire drainage networks, including mobilization of valley floor deposits and removal of vegetation. Comparing 5 streams scoured by debris flows in 1997 and 5 streams that had not been scoured as recently, we determined that debris-flows decreased channel complexity by reducing alluvial step frequency and large woody debris volumes. Unscoured streams had more diverse riparian vegetation, whereas scoured streams were dominated by dense, even-aged stands of white alder (Alnus rhombiflia). Benthic invertebrate shredders, especially nemourid and peltoperlid stoneflies, were more abundant and diverse in unscoured streams, reflecting the more diverse allochthonous resources. Debris flows resulted in increased variability in canopy cover, depending on degree of alder recolonization. Periphyton biomass was higher in unscoured streams, but primary production was greater in the recently scoured streams, suggesting that invertebrate grazers kept algal assemblages in an early successional state. Glossosomatid caddisflies were predominant scrapers in scoured streams; heptageniid mayflies were abundant in unscoured streams. Rainbow trout (Oncorhynchus mykiss) were of similar abundance in scoured and unscoured streams, but scoured streams were dominated by young-of-the-year fish while older juveniles were more abundant in unscoured streams. Differences in the presence of cold-water (Doroneuria) versus warm-water (Calineuria) perlid stoneflies suggest that debris flows have altered stream temperatures. Debris flows have long-lasting impacts on stream communities, primarily through the cascading effects of removal of riparian vegetation. Because debris flow frequency increases following road construction and timber harvest, the long-term biological effects of debris flows on stream ecosystems, including anadromous fish populations, needs to be considered in forest management decisions.

Cover, M. R.; Delafuente, J. A.; Resh, V. H.

2006-12-01

115

Current status of Citrus tristeza virus in Central California  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Lindcove Research and Extension Center (LREC), Exeter, CA has 51 ha of citrus and is the field site and screenhouses for the University of California Citrus Clonal Protection Program (CCPP). LREC maintains a zero tolerance of Citrus tristeza virus (CTV) infected trees to protect the CCPP and re...

116

CURRENT DISTRIBUTION OF THE FISHER, MARTES PENNANTI, IN CALIFORNIA  

Microsoft Academic Search

Wedescribe the 1989-1994 distribution of the fisher, Martes pennanti, in California based on the results of detection surveys that used either sooted track-plates or cameras. Fishers were detected in two regions of the state: the northwest and the southern Sierra Nevada. Despite considerable survey effort, neither fisher tracks nor photographs were collected in the area between Mt. Shasta and Yosemite

WILLIAM J. ZIELINSKI; THOMAS E. KUCERA; REGINALD H. BARRETT

117

Phytoplankton in the California Current system off southern California: Changes in a changing environment  

NASA Astrophysics Data System (ADS)

Patterns of phytoplankton biomass, abundance and composition are examined between 1990 and 2009 over three major scales of environmental variability in the California Current system: seasonal, El Niño-Southern Oscillation (ENSO) and interannual. These patterns are compared with patterns of zooplankton biomass for commonalities and for links that might explain the decrease of zooplankton biomass since the 1970s, and the seemingly paradoxical increase in phytoplankton since 1984. Phytoplankton showed a slow, but significant increase in biomass and a change in species composition. The change appears to be quasi-continuous, with no sign of a more abrupt change around the year 2000. The responses of phytoplankton to ENSO events were weak. Biomass was depressed by El Niño conditions, but an effect of La Niña was not evident. There was no consistent response of species composition to either extreme. The seasonal signal of phytoplankton was strong, evident in biomass, abundance and species composition. The timing and magnitude of the annual maximum changed during the study. Prior to 1998, the annual peak of phytoplankton occurred consistently during the spring months, after which the peak shifted to summer. The shift in annual phytoplankton peak from spring to summer was accompanied by a change in composition, including a 75% decrease in the abundance of Hyalochaete species in the annual peak. The decrease in spring phytoplankton has been offset by an increase in the summer, which suggests a change in the source and timing of the nutrient supply. No evidence was found of an immediate link between phytoplankton abundance or composition and zooplankton biomass. It is postulated that the decline of zooplankton biomass seen since the 1970s is due, not to a decrease in annual primary production, but to shifts in the timing and composition of the annual phytoplankton peak which has destabilized the zooplankton cycle.

Venrick, Elizabeth L.

2012-10-01

118

Population structure of three species of Anisakis nematodes recovered from Pacific sardines (Sardinops sagax) distributed throughout the California Current system.  

PubMed

Members of the Anisakidae are known to infect over 200 pelagic fish species and have been frequently used as biological tags to identify fish populations. Despite information on the global distribution of Anisakis species, there is little information on the genetic diversity and population structure of this genus, which could be useful in assessing the stock structure of their fish hosts. From 2005 through 2008, 148 larval anisakids were recovered from Pacific sardine (Sardinops sagax) in the California Current upwelling zone and were genetically sequenced. Sardines were captured off Vancouver Island, British Columbia in the north to San Diego, California in the south. Three species, Anisakis pegreffii, Anisakis simplex 'C', and Anisakis simplex s.s., were identified with the use of sequences from the internal transcribed spacers (ITS1 and ITS2) and the 5.8s subunit of the nuclear ribosomal DNA. The degree of nematode population structure was assessed with the use of the cytochrome c oxidase 2 (cox2) mitochondrial DNA gene. All 3 Anisakis species were distributed throughout the study region from 32°N to 50°N latitude. There was no association between sardine length and either nematode infection intensity or Anisakis species recovered. Larval Anisakis species and mitochondrial haplotype distributions from both parsimony networks and analyses of molecular variance revealed a panmictic distribution of these parasites, which infect sardines throughout the California Current ecosystem. Panmictic distribution of the larval Anisakis spp. populations may be a result of the presumed migratory pathways of the intermediate host (the Pacific sardine), moving into the northern portion of the California Current in summer and returning to the southern portion to overwinter and spawn in spring. However, the wider geographic range of paratenic (large piscine predators), and final hosts (cetaceans) can also explain the observed distribution pattern. As a result, the recovery of 3 Anisakis species and a panmictic distribution of their haplotypes could not be used to confirm or deny the presence of population subdivision of Pacific sardines in the California Current system. PMID:21506810

Baldwin, Rebecca E; Rew, Mary Beth; Johansson, Mattias L; Banks, Michael A; Jacobson, Kym C

2011-08-01

119

Rizzo, D. M. 2003. Sudden Oak Death: Host plants in forest ecosystems in California and Oregon. Sudden Oak Death Online Symposium. www.apsnet.org/online/SOD (website of The  

E-print Network

Rizzo, D. M. 2003. Sudden Oak Death: Host plants in forest ecosystems in California and Oregon. Sudden Oak Death Online Symposium. www.apsnet.org/online/SOD (website of The American Phytopathological Society). doi:10.1094/SOD-2003-DR Sudden Oak Death: Host plants in forest ecosystems in California

120

Salmonella spp., Vibrio spp., Clostridium perfringens, and Plesiomonas shigelloides in marine and freshwater invertebrates from coastal California ecosystems.  

PubMed

The coastal ecosystems of California are highly utilized by humans and animals, but the ecology of fecal bacteria at the land-sea interface is not well understood. This study evaluated the distribution of potentially pathogenic bacteria in invertebrates from linked marine, estuarine, and freshwater ecosystems in central California. A variety of filter-feeding clams, mussels, worms, and crab tissues were selectively cultured for Salmonella spp., Campylobacter spp., Escherichia coli-O157, Clostridium perfringens, Plesiomonas shigelloides, and Vibrio spp. A longitudinal study assessed environmental risk factors for detecting these bacterial species in sentinel mussel batches. Putative risk factors included mussel collection near higher risk areas for livestock or human sewage exposure, adjacent human population density, season, recent precipitation, water temperature, water type, bivalve type, and freshwater outflow exposure. Bacteria detected in invertebrates included Salmonella spp., C. perfringens, P. shigelloides, Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio alginolyticus. Overall, 80% of mussel batches were culture positive for at least one of the bacterial species, although the pathogens Campylobacter, E. coli-O157, and Salmonella were not detected. Many of the same bacterial species were also cultured from upstream estuarine and riverine invertebrates. Exposure to human sewage sources, recent precipitation, and water temperature were significant risk factors for bacterial detection in sentinel mussel batches. These findings are consistent with the hypothesis that filter-feeding invertebrates along the coast concentrate fecal bacteria flowing from land to sea and show that the relationships between anthropogenic effects on coastal ecosystems and the environmental niches of fecal bacteria are complex and dynamic. PMID:16897302

Miller, W A; Miller, M A; Gardner, I A; Atwill, E R; Byrne, B A; Jang, S; Harris, M; Ames, J; Jessup, D; Paradies, D; Worcester, K; Melli, A; Conrad, P A

2006-08-01

121

Fine root production across a primary successional ecosystem chronosequence at Mt. Shasta, California.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Estimating changes in belowground biomass and production is essential for understanding fundamental patterns and processes during ecosystem development. We examined patterns of fine root production, aboveground litterfall, and forest floor accumulation during forest primary succession at the Mt. Sha...

122

Using sensitive montane amphibian species as indicators of hydroclimatic change in meadow ecosystems of the Sierra Nevada, California  

NASA Astrophysics Data System (ADS)

Climate change can affect sensitive species and ecosystems in many ways, yet sparse data and the inability to apply various climate models at functional spatial scales often prevents relevant research from being utilized in conservation management plans. Climate change has been linked to declines and disturbances in a multitude of species and habitats, and in California, one of the greatest climatic concerns is the predicted reduction in mountain snowpack and associated snowmelt. These decreases in natural storage of water as snow in mountain regions can affect the timing and variability of critical snowmelt runoff periods—important seasonal signals that species in montane ecosystems have evolved life history strategies around—leading to greater intra-annual variability and diminished summer and fall stream flows. Although many species distribution models exist, few provide ways to integrate continually updated and revised Global Climate Models (GCMs), hydrologic data unique to a watershed, and ecological responses that can be incorporated into conservation strategies. This study documents a novel and applicable method of combining boosted regression tree (BRT) modeling and species distributions with hydroclimatic data as a potential management tool for conservation. Boosted regression trees are suitable for ecological distribution modeling because they can reduce both bias and variance, as well as handle sharp discontinuities common in sparsely sampled species or large study areas. This approach was used to quantify the effects of hydroclimatic changes on the distribution of key riparian-associated amphibian species in montane meadow habitats in the Sierra Nevada at the sub-watershed level. Based on modeling using current species range maps in conjunction with three climate scenarios (near, mid, and far), extreme range contractions were observed for all sensitive species (southern long-toed salamander, mountain yellow-legged frog, Yosemite toad) by the year 2100. Among many environmental and hydroclimatic variables used in the model, snowpack and snowmelt (runoff) variables were consistently among the most informative in predicting species occupancy. Few sub-watersheds contained greater than 50% probability of species occupancy throughout the modeled time period; however several core areas were identified as more resilient to climate change for each species. There was overlap among species in areas that were predicted to remain hydroclimatically stable, particularly in sub-watersheds that contain high meadow density. Quantifying these areas of habitat stability, or "resiliency", may ultimately be the most useful outcome of BRT modeling, with the flexibility to utilize multiple GCMs at varying scales. Ultimately managers need to consider both short term and long term conservation goals by identifying and protecting suitable habitat areas most resilient to climate change to give multiple species the best chance to persist. This approach provides a unique tool for conservation management which can be easily applied to a variety of data and species, and provides useful knowledge at both near and long term time scales.

Peek, R.; Viers, J.; Yarnell, S. M.

2012-12-01

123

Cumulative Human Impacts on Mediterranean and Black Sea Marine Ecosystems: Assessing Current Pressures and  

E-print Network

Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America, 2 National Center for Ecological Analysis and Synthesis, Santa Barbara, California, United States of America, California, United States of America, 3 ESRI, Redlands, California, United States of America, 4 Miramare

Lewison, Rebecca

124

Tracking Progress Last updated 6/2/2014 Current and Expected Energy From Coal for California 1  

E-print Network

Tracking Progress Last updated 6/2/2014 Current and Expected Energy From Coal for California 1 Actual and Expected Energy From Coal for California - Overview Electricity supplies from existing coal in California load during 2012. A little over 93 percent of this coal-based energy came from power plants

125

Sierra Nevada Ecosystem Project: Final report to Congress, Addendum. Davis: University of California, Centers for Water and Wildland Resources, 1996. MediatedSettlementAgreement  

E-print Network

database as the basis for future design of adaptive management re- gimes for ecosystem management of giant- ation, and informed by many chapters (1996, SNEP reports). GIANT SEQUOIA GROVE DATABASE The management of Environmental Science, Policy & Management University of California, Berkeley, CA and U.S.D.A., Forest Service

Stephens, Scott L.

126

Hypoxia in high-resolution sediment records: reconstructing the California Current Oxygen Minimum Zone on multi-decadal timescales  

NASA Astrophysics Data System (ADS)

The recent deglaciation event is an ideal laboratory to study the rapid expansion of Oxygen Minimum Zones (OMZs) and the ecological ramifications of such events. Santa Barbara Basin (SBB) sediments are high-resolution archives of seafloor ecosystems, recording both global-scale climate and regional-scale hydrographic events. Seafloor hypoxia in the California Current Ecosystem (CCE) is caused by OMZs in intermediate water depths (300-1200 m), and produces striking evidence in SBB sediment archives. We construct a vertical transect of proxies across SBB (34° 15'N, 119° 45'W) using a core from 418 m water depth (MV0811-15JC), and previously investigated cores from 440 m (MD02-2504) and 570 m (MD02-2503) water depths. Benthic foraminiferal assemblages and planktonic ?18O proxies were quantified at all three depths, while benthic invertebrate communities were quantified in the shallowest core at a 1-cm resolution (~10 years). This high-resolution invertebrate record provides a window into rapid, decadal-scale environmental change in continental margin ecosystems. Seafloor biodiversity is highly variable on 10-10^4 year timescales (across Protist, Mollusc, Arthropod and Echinoderm taxonomic groups), and is tightly coupled to both regional-scale environmental change and global-scale climate events. Additionally, we provide evidence that strongly hypoxic waters shoaled to <300 m water depth at Termination 1A (14.7 ka), implying that the upper boundary of the regional OMZ can expand >150 m on multi-decadal timescales. These data confirm that OMZs have rapidly expanded in the CCE during previous events of global-scale warming, and that continental margin seafloor biodiversity is variable on previously undescribed timescales.

Moffitt, S. E.; Hill, T. M.

2012-12-01

127

ORGANIC POLLUTANT DEPOSITION TO THE SIERRA NEVADA (CALIFORNIA, USA) SNOWPACK AND ASSOCIATED LAKE AND STREAM ECOSYSTEM  

EPA Science Inventory

High elevation ecosystems in the western USA and Canada are receiving deposition of persistent organic pollutants (POPs) that presumably originate in the USA as well as outside its borders. In April 1992 we obtained paired snowpack samples from each of two watersheds located in t...

128

Integrated Approach to Evaluate Impacts of Climate Change on the Water-Energy-Ecosystem Nexus in California  

NASA Astrophysics Data System (ADS)

The Central Valley Project Integrated Resource Plan (CVP IRP) is charting a path to anticipate and adapt to the numerous water resources management challenges confronting the CVP in the twenty-first century, including water supply reliability, infrastructure and operations, socioeconomic and environmental conditions, and changing climate. Climate has significant influence on the water, energy, agricultural, and ecological resources in this system in the Central Valley, California. Water management for agriculture, municipal and industrial, and ecological purposes in turn has potential significant influences on energy and climate. The CVP IRP is developing and applying an integrated suite of modeling tools for evaluating the water-energy-ecosystem nexus within the context of a changing climate. Five transient climate sequences sampled from the more than 100 downscaled climate change projections were developed, blended with observed sequences of historical meteorology, and incorporated as the driving meteorological data for an integrated suite of impact models. Water, energy, and ecological systems analyses were conducted with an integrated suite of models that were expanded to evaluate greenhouse gas emissions associated with system operations and with selection of new water-energy sources. The integrated water-energy-ecosystem approach and tools are being used to make planning decisions of significant water management directions for the CVP. The present paper will demonstrate the practical integrated approach developed within the CVP IRP scope, and discuss its broader applicability.

Munevar, A.; Das, T.

2012-12-01

129

Potential effects of acid deposition on aquatic ecosystems of the Sierra Nevada, California  

Microsoft Academic Search

Acid deposition has been measured in California, including areas of the Sierra Nevada, during federal and state sponsored monitoring programs. The mountainous Sierra Nevada is characterized by low-alkalinity, granitic-basin lakes which may be sensitive to acid inputs, particularly during the snowmelt period. The field survey established that lakes located in subalpine basins on the western slope of the Sierra have

Tonnessen

1983-01-01

130

Positive Effects of Non-Native Grasses on the Growth of a Native Annual in a Southern California Ecosystem  

PubMed Central

Fire disturbance is considered a major factor in the promotion of non-native plant species. Non-native grasses are adapted to fire and can alter environmental conditions and reduce resource availability in native coastal sage scrub and chaparral communities of southern California. In these communities persistence of non-native grasses following fire can inhibit establishment and growth of woody species. This may allow certain native herbaceous species to colonize and persist beneath gaps in the canopy. A field manipulative experiment with control, litter, and bare ground treatments was used to examine the impact of non-native grasses on growth and establishment of a native herbaceous species, Cryptantha muricata. C. muricata seedling survival, growth, and reproduction were greatest in the control treatment where non-native grasses were present. C. muricata plants growing in the presence of non-native grasses produced more than twice the number of flowers and more than twice the reproductive biomass of plants growing in the treatments where non-native grasses were removed. Total biomass and number of fruits were also greater in the plants growing in the presence of non-native grasses. Total biomass and reproductive biomass was also greater in late germinants than early germinants growing in the presence of non-native grasses. This study suggests a potential positive effect of non-native grasses on the performance of a particular native annual in a southern California ecosystem. PMID:25379790

Pec, Gregory J.; Carlton, Gary C.

2014-01-01

131

Bottom current and sediment transport on San Pedro Shelf, California  

USGS Publications Warehouse

GEOPROBE (Geological Processes Bottom Environmental) tripods were used to measure bottom currents, pressure, and light transmission and scattering and to obtain time-series photographs of the sea floor at depths of 23 m and 67 m on San Pedro shelf between 18 April and 6 June 1978. Winds were light (< 5 m/s) with a mean direction from the southwest throughout the measurement period. Hourly averaged currents 1 m above the bottom never exceeded 21 cm/s; average speeds were about 5 cm/s at the 23-m site and 6.8 cm/s at 67 m, and the strongest currents were produced by the tides. The mean flow of bottom water was less than 3 cm/s at both GEOPROBES and was rather persistently southward (offshelf). Wave-generated bottom currents and bottom-pressure variations were sampled at hourly intervals; average wave period and wave height were 12.8 s and 0.44 m, respectively, at the 23-m site. Wave orbital velocities ranged from about 5 to 30 cm/s at 23 m and from 2 to 8 cm/s at 67 m. Bottom photographs at 67 m show that the relatively sluggish tide-generated and mean currents were below threshold velocity for the silty, very fine sand throughout the observational period. Threshold depth for wave rippling of very fine sand averaged about 28 m with a range from about 12 m to 50 m. Wave-generated currents were the only currents that exceeded threshold levels. The wave currents maintained relatively high concentrations of sediment in suspension near the bottom over the inner shelf (< 25 m), and this material (principally silt and clay) was transported offshore by the weak mean flow. Approximately 50% of this material was deposited as the bottom orbital velocities decreased to subthreshold values ( nearly equal 10-15 cm/s). The observed movement of fine sediment across the inner shelf can account for a portion of the mud content of the modern silty sands on the central shelf and on the outer shelf. However, it is clear that the sand fractions, which constitute greater than 70% of the central shelf substrate, must be transported during high-energy winter storms.

Drake, David E.; Cacchione, David A.; Karl, Herman A.

1985-01-01

132

Poleward flows in the southern California Current System: Glider observations and numerical simulation  

Microsoft Academic Search

Three years of continuous Spray glider observations in the southern California Current System (CCS) are combined with a numerical simulation to describe the mean and variability of poleward flows in the southern CCS. Gliders provide upper ocean observations with good across-shore and temporal resolution along two across-shore survey lines while the numerical simulation provides a dynamically consistent estimate of the

Robert E. Todd; Daniel L. Rudnick; Matthew R. Mazloff; Russ E. Davis; Bruce D. Cornuelle

2011-01-01

133

DEVELOPMENT AND USE OF SONAR MAPPING FOR PELAGIC STOCK ASSESSMENT IN THE CALIFORNIA CURRENT AREAl  

E-print Network

Research pro- gram notes the use of sonar and echo sounders on the RV Yellowfin for locating fish schools) and in the California Current area (Smith 1970). For recent reviews of the use of echo sounders and sonars for fishery for locating concentrations of fish for almost as long as practical echo sounding devices have been available

134

RANGE EXPANSION AND TROPHIC INTERACTIONS OF THE JUMBO SQUID, DOSIDICUS GIGAS, IN THE CALIFORNIA CURRENT  

Microsoft Academic Search

Although jumbo squid (Dosidicus gigas) have been oc- casional visitors to the California Current over the last century, their abundance and distribution increased be- tween 2002 and 2006. We report several time series of jumbo squid relative abundance from commercial and recreational fisheries as well as resource surveys and food habits studies. To evaluate the trophic relationships of jumbo squid,

JOHN C. FIELD; KEN BALTZ; A. JASON PHILLIPS

135

Effects of Debris Flows on Stream Ecosystems of the Klamath Mountains, Northern California  

Microsoft Academic Search

We examined the long-term effects of debris flows on channel characteristics and aquatic food webs in steep (0.04-0.06 slope), small (4-6 m wide) streams. A large rain-on-snow storm event in January 1997 resulted in numerous landslides and debris flows throughout many basins in the Klamath Mountains of northern California. Debris floods resulted in extensive impacts throughout entire drainage networks, including

J. A. Delafuente; V. H. Resh

2006-01-01

136

Soil N and 15N variation with time in a California annual grassland ecosystem  

NASA Astrophysics Data System (ADS)

The %N and ? 15N values of soils and plants were measured along a chronosequence spanning 3 to 3000 Ky in a California annual grassland. Total soil N decreased with increasing soil age (1.1 to 0.4 kg N m -2) while the mean ? 15N values of the soil N increased by several ‰ from the youngest to oldest sites (+3.5 to +6.2 ‰). The ? 15N values of plants varied along the gradient, reflecting changing soil N pools and differences in the form of N uptake. The decline in total N storage with time is hypothesized to be due to a shift from N to P limitation with increasing soil age. The general increase in ? 15N values with time is interpreted using a N mass balance model, and appears to reflect a shift toward an increasing proportional losses of inorganic mineral forms of N (vs. organic forms) with increasing soil age. We develop a quantitative index of this trend (mineral vs. organic forms of N loss) using mass balance considerations and parameters. The %N and ? 15N values along the California age gradient were compared to the published data for a comparably aged chronosequence in Hawaii. Most striking in this comparison is the observation that the California soil and plant ? 15N values are several ‰ greater than those on comparably aged Hawaiian sites. Multiple explanations are plausible, but assuming the sites have a similar range in ? 15N values of atmospheric inputs, the isotopic differences suggest that N may be, at least seasonally, in greater excess in the strongly seasonal, semi-arid, California grassland.

Brenner, Dana L.; Amundson, Ronald; Baisden, W. Troy; Kendall, Carol; Harden, Jennifer

2001-11-01

137

234Th:238U disequilibria within the California Current  

Microsoft Academic Search

Profiles of dissolved and particulate 234Th were determined at several stations within the Cali- fornia Current. Modeling of the disequilibria between the 234Th and 23aU within the surface waters provides for estimates of the residence time of dissolved thorium with respect to particle scavenging (TP varies from 6 to 50 days), the particle residence time (TP varies from 2 to

KENNETH H. COALE; KENNETH W. BRULAND

1985-01-01

138

Trophic modeling of the Northern Humboldt Current Ecosystem, Part II: Elucidating ecosystem dynamics from 1995 to 2004 with a focus on the impact of ENSO  

NASA Astrophysics Data System (ADS)

The Northern Humboldt Current Ecosystem is one of the most productive in the world in terms of fish production. Its location near to the equator permits strong upwelling under relatively low winds, thus creating optimal conditions for the development of plankton communities. These communities ultimately support abundant populations of grazing fish such as the Peruvian anchoveta, Engraulis ringens. The ecosystem is also subject to strong inter-annual environmental variability associated with the El Niño Southern Oscillation (ENSO), which has major effects on nutrient structure, primary production, and higher trophic levels. Here our objective is to model the contributions of several external drivers (i.e. reconstructed phytoplankton changes, fish immigration, and fishing rate) and internal control mechanisms (i.e. predator-prey) to ecosystem dynamics over an ENSO cycle. Steady-state models and time-series data from the Instituto del Mar del Perú (IMARPE) from 1995 to 2004 provide the base data for simulations conducted with the program Ecopath with Ecosim. In simulations all three external drivers contribute to ecosystem dynamics. Changes in phytoplankton quantity and composition (i.e. contribution of diatoms and dino- and silicoflagellates), as affected by upwelling intensity, were important in dynamics of the El Niño of 1997-98 and the subsequent 3 years. The expansion and immigration of mesopelagic fish populations during El Niño was important for dynamics in following years. Fishing rate changes were the most important of the three external drivers tested, helping to explain observed dynamics throughout the modeled period, and particularly during the post-El Niño period. Internal control settings show a mix of predator-prey control settings; however a “wasp-waist” control of the ecosystem by small pelagic fish is not supported.

Taylor, Marc H.; Tam, Jorge; Blaskovic, Verónica; Espinoza, Pepe; Michael Ballón, R.; Wosnitza-Mendo, Claudia; Argüelles, Juan; Díaz, Erich; Purca, Sara; Ochoa, Noemi; Ayón, Patricia; Goya, Elisa; Gutiérrez, Dimitri; Quipuzcoa, Luis; Wolff, Matthias

2008-10-01

139

Spatial dynamics of anchovy, sardine, and hake pre-recruit stages in the California Current  

Microsoft Academic Search

Smith, P. E., Horne, J. K., and Schneider, D. C. 2001. Spatial dynamics of anchovy, sardine, and hake pre-recruit stages in the California Current. - ICES Journal of Marine Science, 58: 1063-1071. Three genera, Engraulis, Sardinops ,a ndMerlucciu have coincident spawning and juvenile brood areas in most eastern and western boundary currents throughout the world. The CalCOFI survey program has

P. E. Smith; J. K. Horne; D. C. Schneider

2001-01-01

140

In press in: Whales, Whaling and Marine Ecosystems, James Estes, ed., University of California Press, 12/03 Bigger is Better: The Role of Whales as Detritus in Marine Ecosystems  

E-print Network

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 In press in: Whales, Whaling and Marine Ecosystems, James Estes, ed., University of California Press, 12/03 Bigger is Better: The Role of Whales Pope Road Honolulu, HI 96734 USA Email: csmith@soest.hawaii.edu 1 #12;Abstract. Dead whales

Smith, Craig

141

Carbon Sequestration and Nitrous Oxide Emissions from Urban Turfgrass Ecosystems in Southern California  

NASA Astrophysics Data System (ADS)

Irrigated turfgrass ecosystems sequester carbon in soil organic matter, but they may also release nitrous oxide, due to fertilization associated with intensive management practices. Nitrous oxide is an important green house gas with a global warming potential (GWP) of 300 times that of carbon dioxide on a 100 yr time horizon. Although regular irrigation and fertilization of turfgrass create favorable conditions for both C storage and N2O release via nitrification and denitrification by soil microbes, emissions from these highly managed ecosystems are poorly constrained. We quantified N2O emissions and C storage rates for turf grass in four urban parks in the city of Irvine, CA. The turf grass systems we studied were managed by the City of Irvine. Parks were established between 1975 and 2006 on former range land with the same initial parent material; are exposed to the same climate; and form a time series (chronosequence) for investigating rates of C accumulation. We also investigated the effects of management (e.g. grass species, fertilization rate), soil moisture and temperature, and park age on N2O emission from these parks. We quantified N2O emissions using static soil chamber with four 7 min. sampling intervals, and analyzed the samples using an electron capture gas chromatograph. Soil carbon accumulation rates were determined from the slope of the organic C inventory (from 0-20 cm depth) plotted against park age. C storage rates for soils in "leisure" areas were close to 2 Mg C ha-1 yr-1, similar to rates associated with forest regrowth in northeastern US forests. However, as park age and C storage increased, N2O emissions increased as well, such that emissions from the older parks (~20 ngN m-2 s-1) were comparable to published temperate agricultural fluxes. Initial estimates suggest that the GWP associated with N2O emissions approximately offsets the effect of C storage in these ecosystems.

Ampleman, M. D.; Czimczik, C. I.; Townsend-Small, A.; Trumbore, S. E.

2008-12-01

142

Land Use Compounds Habitat Losses under Projected Climate Change in a Threatened California Ecosystem  

PubMed Central

Given the rapidly growing human population in mediterranean-climate systems, land use may pose a more immediate threat to biodiversity than climate change this century, yet few studies address the relative future impacts of both drivers. We assess spatial and temporal patterns of projected 21st century land use and climate change on California sage scrub (CSS), a plant association of considerable diversity and threatened status in the mediterranean-climate California Floristic Province. Using a species distribution modeling approach combined with spatially-explicit land use projections, we model habitat loss for 20 dominant shrub species under unlimited and no dispersal scenarios at two time intervals (early and late century) in two ecoregions in California (Central Coast and South Coast). Overall, projected climate change impacts were highly variable across CSS species and heavily dependent on dispersal assumptions. Projected anthropogenic land use drove greater relative habitat losses compared to projected climate change in many species. This pattern was only significant under assumptions of unlimited dispersal, however, where considerable climate-driven habitat gains offset some concurrent climate-driven habitat losses. Additionally, some of the habitat gained with projected climate change overlapped with projected land use. Most species showed potential northern habitat expansion and southern habitat contraction due to projected climate change, resulting in sharply contrasting patterns of impact between Central and South Coast Ecoregions. In the Central Coast, dispersal could play an important role moderating losses from both climate change and land use. In contrast, high geographic overlap in habitat losses driven by projected climate change and projected land use in the South Coast underscores the potential for compounding negative impacts of both drivers. Limiting habitat conversion may be a broadly beneficial strategy under climate change. We emphasize the importance of addressing both drivers in conservation and resource management planning. PMID:24466116

Riordan, Erin Coulter; Rundel, Philip W.

2014-01-01

143

Land use compounds habitat losses under projected climate change in a threatened California ecosystem.  

PubMed

Given the rapidly growing human population in mediterranean-climate systems, land use may pose a more immediate threat to biodiversity than climate change this century, yet few studies address the relative future impacts of both drivers. We assess spatial and temporal patterns of projected 21(st) century land use and climate change on California sage scrub (CSS), a plant association of considerable diversity and threatened status in the mediterranean-climate California Floristic Province. Using a species distribution modeling approach combined with spatially-explicit land use projections, we model habitat loss for 20 dominant shrub species under unlimited and no dispersal scenarios at two time intervals (early and late century) in two ecoregions in California (Central Coast and South Coast). Overall, projected climate change impacts were highly variable across CSS species and heavily dependent on dispersal assumptions. Projected anthropogenic land use drove greater relative habitat losses compared to projected climate change in many species. This pattern was only significant under assumptions of unlimited dispersal, however, where considerable climate-driven habitat gains offset some concurrent climate-driven habitat losses. Additionally, some of the habitat gained with projected climate change overlapped with projected land use. Most species showed potential northern habitat expansion and southern habitat contraction due to projected climate change, resulting in sharply contrasting patterns of impact between Central and South Coast Ecoregions. In the Central Coast, dispersal could play an important role moderating losses from both climate change and land use. In contrast, high geographic overlap in habitat losses driven by projected climate change and projected land use in the South Coast underscores the potential for compounding negative impacts of both drivers. Limiting habitat conversion may be a broadly beneficial strategy under climate change. We emphasize the importance of addressing both drivers in conservation and resource management planning. PMID:24466116

Riordan, Erin Coulter; Rundel, Philip W

2014-01-01

144

The impact of antecedent fire area on burned area in southern California coastal ecosystems.  

PubMed

Frequent wildfire disasters in southern California highlight the need for risk reduction strategies for the region, of which fuel reduction via prescribed burning is one option. However, there is no consensus about the effectiveness of prescribed fire in reducing the area of wildfire. Here, we use 29 years of historical fire mapping to quantify the relationship between annual wildfire area and antecedent fire area in predominantly shrub and grassland fuels in seven southern California counties, controlling for annual variation in weather patterns. This method has been used elsewhere to measure leverage: the reduction in wildfire area resulting from one unit of prescribed fire treatment. We found little evidence for a leverage effect (leverage = zero). Specifically our results showed no evidence that wildfire area was negatively influenced by previous fires, and only weak relationships with weather variables rainfall and Santa Ana wind occurrences, which were variables included to control for inter-annual variation. We conclude that this is because only 2% of the vegetation burns each year and so wildfires rarely encounter burned patches and chaparral shrublands can carry a fire within 1 or 2 years after previous fire. Prescribed burning is unlikely to have much influence on fire regimes in this area, though targeted treatment at the urban interface may be effective at providing defensible space for protecting assets. These results fit an emerging global model of fire leverage which position California at the bottom end of a continuum, with tropical savannas at the top (leverage = 1: direct replacement of wildfire by prescribed fire) and Australian eucalypt forests in the middle (leverage ~ 0.25). PMID:23064248

Price, Owen F; Bradstock, Ross A; Keeley, Jon E; Syphard, Alexandra D

2012-12-30

145

Background trends in California Current surface chlorophyll concentrations: A state-space view  

NASA Astrophysics Data System (ADS)

State-space models are applied to 13 years of monthly satellite-measured chlorophyll concentrations of the California Current, from British Columbia to Baja California, to isolate the slowly varying background trend from potentially nonstationary seasonal cycles, other higher-frequency cyclical variability, and an irregular plus measurement error signal. Temporal patterns in resulting background trends cluster into four dominant groups, three of which have increasing trends, the strongest of which extends over the coastal upwelling region from southern Oregon to Point Conception, California, and has a mean of 0.118 mg CHL m-3 decade-1. Overall, statistically significant increasing trends are observed over 75% of the study area, 20% of the study area had no trend, and 5% showed decreasing chlorophyll. Location-specific trend estimation shows increases are strongest (> 0.2 mg CHL m-3 decade-1) in upwelling areas along the Washington, Oregon and central California coasts, weaker in regions > 200 km offshore, and that positive trends are statistically significant over most of the California Current north of ˜27°N. Negative trends are evident south of ˜31°N off Baja California. These trends remain significant with similar spatial pattern, but lower magnitude, when the 1997-1998 El Niño period is removed from the analysis. State-space models of trends in alongshore wind stress and sea surface temperature over the same period indicate that local mechanisms linked to these chlorophyll trends are not clear. Comparisons of the chlorophyll trends to nonlocal signals, characterized by the North Pacific Gyre Oscillation and the Multivariate El Niño Index, map the spatially varying ecological footprint of these basin-scale signals.

Thomas, Andrew C.; Mendelssohn, Roy; Weatherbee, Ryan

2013-10-01

146

A: Coastal and Ocean Ecosystems Current Findings Linking Plume and Ocean Conditions to Salmon Growth and Survival  

E-print Network

A: Coastal and Ocean Ecosystems ­ Current Findings Linking Plume and Ocean Conditions to Salmon conditions in the Pacific Northwest region were poor, and ocean survival of Columbia River salmon was significantly affected. New insights now demonstrate that variations in salmon abundance are linked to phenomena

147

Interactions between climate and forest ecosystems: a review of current debates and perspectives in a global warming scenario  

Microsoft Academic Search

Although climate change is a natural part of the dynamics of our plan et, current speed and magnitude of change, and our capacity to forecast its consequences, are of great concern. Considering the ecological and economic importance of forests, and their intricate relation with climate, several studies have focused on interactions between climate and forest ecosystems, and on the consequences

Luiz Francisco Ditzel

2009-01-01

148

Root distribution in a California semi-arid oak savanna ecosystem as determined by conventional sampling and ground penetrating radar  

NASA Astrophysics Data System (ADS)

Koteen, Laura E., Raz-Yaseef, Naama, and Dennis D. Baldocchi University of California, Berkeley California's blue oak, Quercus douglasii, is a unique tree in several ways. Despite the intense heat of California's central valley and Sierra foothills, and absence of precipitation during dry summer months, blue oaks are winter deciduous, and rely on a suite of drought adaptation measures for highly-efficient water use. To date, much more is known about aboveground dynamics in semi-arid oak savanna ecosystems than belowground. Yet, the root system is instrumental in ensuring oak survival and in determining the magnitude and timing of land-atmospheric fluxes via its control of water and nutrient supply to aboveground processes and soil moisture content. Tree root distribution is notoriously heterogeneous. Therefore a comprehensive sampling effort is needed in order to optimally represent it. To further understand the patterns of water use in oak savanna ecosystems in the Sierra foothills of California, we have sought to characterize the root system by depth. To accomplish this goal, we have sampled the root system using conventional sampling methods (i.e. pit and core sampling), in conjunction with ground penetrating radar (GPR). Using both methods together made it possible to compensate for the limitations of each: Fine roots can only be detected by conventional sampling, and involve time intensive work in the lab, limiting sample size. GPR, on the other hand, allows for much greater spatial coverage and therefore more comprehensive characterization of the coarse root component. An extensive field campaign was executed during May 2011. 7 tree areas where chosen, representing the range of tree sizes and composition at the research site: 2 small trees, 2 large trees and 2 tree clusters. One additional very large tree that has undergone extensive additional physiological measurements was also chosen in order to posit and test hypotheses about linkages among root, soil water and photosynthetic processes. We extracted root cores according to a radial sampling scheme, with a 5 cm diameter soil auger at distances of 0.5, 1 and 1.5 the mean canopy radius from the tree. Soil cores were removed in intervals from 0-10, 10-20, 20-40, 40-60, and 60 cm to bedrock, which varied in depth from 20 cm to 1 meter. Fine roots were rinsed of soil, separated from debris, dried and weighed. GPR measurements were conducted using Noggin1000 (Sensors and Software Inc.). Prior to measurements, 8 by 8 m grids were prepared, with line density of 20 cm. Following GPR measurements, 2 pits of size 60 by 100 cm were dug down to the bedrock. Coarse roots were removed in regular depth intervals, sieved and taken to the lab. In the lab, coarse roots were washed of soil, dried, sorted into size classes and weighed. GPR visual data was analyzed using appropriate software, and the number of pixels identified as roots was linked to root biomass from pits. Lastly, 3D imaging of the root structure was achieved through the use of visualization software. The knowledge we have gained through this research will be used to improve our understanding of tree water usage, and soil moisture dynamics in this semi-arid oak savanna system.

Koteen, L. E.; Raz-Yaseef, N.; Baldocchi, D. D.

2011-12-01

149

Toxic contaminants and Great Lakes ecosystem health: current understandings and strategies for improved assessments  

Microsoft Academic Search

Although extensive research, surveillance, and monitoring studies have been conducted on the Great Lakes ecosystem for more than two decades, the presence of toxic substances in the Great Lakes ecosystem continues to be a major issue of environmental concern. This issue was addressed during a symposium and workshop sponsored by the International Joint Commission during which more than 30 experts

Marlene S. Evans

1993-01-01

150

Holocene climate variability in the NE Pacific: Insight from connections between the Gulf of Alaska and the California Current System  

NASA Astrophysics Data System (ADS)

Historically, decadal-scale climatic change in the North Pacific region appears to be characterized by circulation modes with coherent and recognizable spatial patterns (i.e., PDO). Examination of trends in paleo-records from widespread regions, allow recognition of how these modes have varied over time. Changes in patterns of correlations of proxies between regions suggest several periods of reorganization of ocean-atmospheric circulation during the Holocene. Major shifts appear to have occurred during climatic transitions into the Neoglacial period (ca 4000 BP), and into and out of the Little Ice Age (LIA; ca. AD 1200 and 1850). Recent paleoclimatic studies from Mt, Logan ice cores and elsewhere suggest these transitions reflect shifts between atmospheric circulation modes of more zonal vs. more meridional flow. These shifts in climate can be tracked into variability in primary productivity and higher trophic levels, such as pelagic fish, in the North Pacific marine ecosystem. Within the Gulf of Alaska, new high-resolution reconstructions of ocean paleoproductivity based on multiproxy analysis of sediment cores suggest persistent variability over multidecadal scales, punctuated by abrupt state changes in overall productivity level. Such “mega-regime shifts” are of a different nature and larger amplitude than historical regime-shifts. Records of Alaskan salmon are generally positively correlated with Gulf of Alaska productivity. Interestingly, records of California Current sardine and anchovy abundance reveal different relationships to Alaska salmon abundance during the LIA relative to historical observations. It is likely that a different pattern of ocean-atmospheric circulation during the LIA, resulted in different relationships between these regional ecosystems.

Finney, B. P.; Addison, J. A.

2009-12-01

151

Preface to special section on enhanced Subarctic influence in the California Current, 2002  

NASA Astrophysics Data System (ADS)

This special section discusses a rare phenomenon: strong enhancement of Subarctic influence in the California Current system in the summer of 2002. This cold, fresh anomaly in the upper halocline was more extreme than any prior observation, though historical records extend back for several decades. The Subarctic anomaly extended more than 1500 km along the U. S. west coast, from 49°N to 33°N. It brought high-nutrient waters into the coastal upwelling zone off Oregon and northern California, and produced exceptionally high chlorophyll concentrations. Inner shelf oxygen concentrations were very high near the surface and very low near the bottom. The presence of this Subarctic water mass was associated with anomalous southward currents detected by three different methods: by satellite-tracked drifters, a mid-shelf mooring, and by satellite altimetry. Large-scale wind forcing over the northeastern Pacific during the previous winter and spring seems to be responsible for these anomalies.

Huyer, Adriana

2003-08-01

152

Effects of sewage discharge on trophic state and water quality in a coastal ecosystem of the Gulf of California.  

PubMed

This paper provides evidence of the effects of urban wastewater discharges on the trophic state and environmental quality of a coastal water body in a semiarid subtropical region in the Gulf of California. The concentrations of dissolved inorganic nutrients and organic matter from urban wastewater primary treatment were estimated. La Salada Cove was the receiving water body and parameters measured during an annual cycle were temperature, salinity, dissolved oxygen, nitrite, nitrate, ammonia, orthophosphate, and chlorophyll a. The effects of sewage inputs were determined by using Trophic State Index (TRIX) and the Arid Zone Coastal Water Quality Index (AZCI). It was observed that urban wastewater of the city of Guaymas provided 1,237 ton N yr(-1) and 811 ton P yr(-1) and TRIX indicated that the receiving water body showed symptoms of eutrophication from an oligotrophic state to a mesotrophic state; AZCI also indicated that the environmental quality of the water body was poor. The effects of urban wastewater supply with insufficient treatment resulted in symptoms of eutrophication and loss of ecological functions and services of the coastal ecosystem in La Salada Cove. PMID:24711731

Vargas-González, Héctor Hugo; Arreola-Lizárraga, José Alfredo; Mendoza-Salgado, Renato Arturo; Méndez-Rodríguez, Lía Celina; Lechuga-Deveze, Carlos Hernando; Padilla-Arredondo, Gustavo; Cordoba-Matson, Miguel

2014-01-01

153

Spatial and interannual variability in mesoscale circulation in the northern California Current System  

Microsoft Academic Search

We used wavelet analyses of sea surface height (SSH) from >13 years of satellite altimeter data to characterize the variability in mesoscale circulation in the northern California Current (35°N–49°N) and explore the mechanisms of variability. We defined “mesoscale” circulation as features, such as eddies and filaments, which have 50- to 300-km length scales and 4- to 18-week temporal scales. Fluctuations

Julie E. Keister; P. Ted Strub

2008-01-01

154

A Comparison between Value-Added School Estimates and Currently Used Metrics of School Accountability in California  

ERIC Educational Resources Information Center

This study compared a value-added approach to school accountability to the currently used metrics of accountability in California of Adequate Yearly Progress (AYP) and Academic Performance Index (API). Five-year student panel data (N?=?53,733) from 29 elementary schools in a large California school district were used to address the research…

Fagioli, Loris P.

2014-01-01

155

Responses of terrestrial ecosystems and carbon budgets to current and future environmental  

E-print Network

the South Asian monsoon (9), and increasing frequency of heat waves (10). Changes in the intermittent of the statistics of this variability is essential for realistic predictions of ecosystem struc- ture

Moorcroft, Paul R.

156

Ecosystem response to regulatory and management actions: the southern California experience in long-term monitoring.  

PubMed

Billions of dollars have been invested over the past 35 years in reducing pollutant emissions to coastal environments. Evaluation of the effectiveness of this investment is hampered by the lack of long-term consistent data. A rare opportunity exists in southern California to evaluate the effectiveness of management actions by analyzing long-term monitoring of effluent, sediment, benthos, and fish and comparing this trend data to periodic regional surveys of environmental condition. In this paper, we ask the question "have improvements in effluent quality in response to environmental regulation translated into improvements in the receiving environment?" Results indicate that management actions directed at reducing mass emissions from wastewater treatment plants (POTWs) have resulted in substantial improvement in aquatic communities. However, the magnitude and timing of response varies by indicator suggesting that use of multiple assessment endpoints is necessary to adequately interpret trends. Reductions in the effect of POTW effluent have allowed managers to shift resources to address other contaminant sources such as stormwater and resuspension of legacy pollutants. PMID:19329129

Stein, Eric D; Cadien, Donald B

2009-01-01

157

Interannual variation in climate-potential net primary productivity relationships in differing ecosystems of California  

SciTech Connect

The seasonality and interannual variation in potential net primary production (NPP) were examined in differing vegetation types in California over three years of contrasting precipitation using co-registered maps of climate, vegetation, and 1km biweekly NDVI derived from high resolution satellite AVHRR data. Differences in seasonality of the vegetation types (annual grassland, chamise chaparral, deciduous oak woodland, and evergreen oak) were clearly evident and corresponded well to patterns observed in field studies. In years and locations having high precipitation the annual peak in NDVI occurred later in all vegetation classes. The annual sum of biweekly NDVI was correlated with annual precipitation in all vegetation types, although the slopes and intercepts of the regressions differed among types. Annual grassland showed the largest increase in sumNDVI per unit increase in total precipitation and most of the variation in grassland sumNDVI was explained by variation in autumn precipitation. In general the ratio of sumNDVI to annual precipitation was dependent on the temporal distribution of precipitation with respect to the long-term average pattern. Published relationships between precipitation and NPP were used to develop equations relating annual NDVI sum to NPP.

Koch, G.W.; Randerson, J.T. (Stanford Univ. Carnegie Institution of Plant Biology, CA (United States))

1994-06-01

158

SignsofAdaptationtoLocalpHConditionsacrossanEnvironmental Mosaic in the California Current Ecosystem  

E-print Network

of the Northeast Pacific Ocean. We also present new results testing for adaptation to local pH conditions in six a set of seven genes as top candidates for rapid evolutionary response to acidification of the ocean for rapid evolution in response to acidification. This adaptive capacity likely comes from standing genetic

Palumbi, Stephen

159

Contributions of the Plankton Community to Ecosystem Respiration, Tomales Bay, California  

NASA Astrophysics Data System (ADS)

This paper presents direct measurements of plankton community respiration for Tomales Bay, California, U.S.A., and compares these measurements with water column variables. These data were used to develop a regression model that predicts planktonic respiration and nutrient remineralization. Respiration was measured as change in dissolved O 2in sealed, dark, 300 ml bottles. There was a consistent and linear decrease in O 2concentrations over 35-48 h incubations. Chlorophyll aconcentration ranged from 1 to 10 ?g chl a l -1. Bacterial counts were 2-11×10 6cells ml -1and leucine incorporation rates ranged from 200 to 1300 pmol l -1h -1over the period May 1992-July 1993. Respiration rates were 0·16-1·91 ?mol O 2l -1h -1, with an annualized average of 0·67 ?mol O 2l -1h -1. A multiple linear regression of O 2consumption rate against the independent variables (chlorophyll concentration, temperature and particulate N concentration) explained 79% of the variation in the respiration rates. Modelled plankton community respiration rates for the period January 1988 to July 1993 ranged from <0·4 to >2·0 ?mol O 2l -1h -1. Over the same period, the average predicted areal respiration for inner Tomales Bay was 64·5 mmol O 2m -2day -1. Mean predicted rates of N and P remineralization over the period of January 1988 to July 1993 were 9·8 and 0·6 mmol m -2day -1, respectively. Even in an embayment as shallow as Tomales Bay (mean z=3·1 m), planktonic respiration and remineralization are greater than benthic respiration and remineralization.

Fourqurean, J. W.; Webb, K. L.; Hollibaugh, J. T.; Smith, S. V.

1997-04-01

160

Correlation scales, objective mapping, and absolute geostrophic flow in the California Current  

NASA Astrophysics Data System (ADS)

The spatial covariances of the time-dependent density and geostrophic velocity fields off southern California are determined from a unique set of repeated hydrographic observations (44 cruises) made by the California Cooperative Oceanic Fisheries Investigations from 1984 to 1994. The covariances and objective analysis are used to combine direct velocity observations, from shipboard acoustic Doppler current profiler (ADCP) measurements made on a recent survey (October 1993), with hydrographic observations. The analysis reduces ageostrophic noise in the ADCP velocities by smoothing and enforcing horizontal nondivergence; additionally, the velocities are mapped over scales that are dynamically consistent with the hydrography. Maximum surface geostrophic flow in the California Current in October 1993 is about 35 cm s-1, 50% larger than that estimated assuming a 500-m level of no motion. Absolute flow at 500 m is O(10 cm s-1) and indicates that the surface eddy field penetrates through the thermocline. Uncertainty in the geostrophic reference calculated from the ADCP measurements is of O(4 cm s-1). The velocity residual (objectively analyzed minus raw ADCP estimates) exhibits smaller correlation scales than the geostrophic flow.

Chereskin, T. K.; Trunnell, M.

1996-10-01

161

Modeling the yield potential of dryland canola under current and future climates in California  

NASA Astrophysics Data System (ADS)

Models predict that the climate of California will become hotter, drier and more variable under future climate change scenarios. This will lead to both increased irrigation demand and reduced irrigation water availability. In addition, it is predicted that most common Californian crops will suffer a concomitant decline in productivity. To remain productive and economically viable, future agricultural systems will need to have greater water use efficiency, tolerance of high temperatures, and tolerance of more erratic temperature and rainfall patterns. Canola (Brassica napus) is the third most important oilseed globally, supporting large and well-established agricultural industries in Canada, Europe and Australia. It is an agronomically useful and economically valuable crop, with multiple end markets, that can be grown in California as a dryland winter rotation with little to no irrigation demand. This gives canola great potential as a new crop for Californian farmers both now and as the climate changes. Given practical and financial limitations it is not always possible to immediately or widely evaluate a crop in a new region. Crop production models are therefore valuable tools for assessing the potential of new crops, better targeting further field research, and refining research questions. APSIM is a modular modeling framework developed by the Agricultural Production Systems Research Unit in Australia, it combines biophysical and management modules to simulate cropping systems. This study was undertaken to examine the yield potential of Australian canola varieties having different water requirements and maturity classes in California using APSIM. The objective of the work was to identify the agricultural regions of California most ideally suited to the production of Australian cultivars of canola and to simulate the production of canola in these regions to estimate yield-potential. This will establish whether the introduction and in-field evaluation of better-adapted canola varieties can be justified, and the potential value of a California canola industry both now and in the future. Winter annual crops like canola use rainfall in a Mediterranean climate like California more efficiently than spring or summer crops. Our results suggest that under current production costs and seed prices, dry farmed canola will have good potential in certain areas of the California. Canola yields decline with annual winter precipitation, however economically viable yields are still achieved at relatively precipitation levels (200 mm). Results from simulation, combined with related economic modeling (reported elsewhere) suggest that canola will be viable in a variety of production systems in the northern Sacramento Valley and some coastal locations, even under drier future climate scenarios. The in-field evaluation of Australian canola varieties should contribute to maintain or improving resource use efficiency and farm profitability.

George, N.; Kaffka, S.; Beeck, C.; Bucaram, S.; Zhang, J.

2012-12-01

162

Environmental fate of fungicides and other current-use pesticides in a central California estuary  

USGS Publications Warehouse

The current study documents the fate of current-use pesticides in an agriculturally-dominated central California coastal estuary by focusing on the occurrence in water, sediment and tissue of resident aquatic organisms. Three fungicides (azoxystrobin, boscalid, and pyraclostrobin), one herbicide (propyzamide) and two organophosphate insecticides (chlorpyrifos and diazinon) were detected frequently. Dissolved pesticide concentrations in the estuary corresponded to the timing of application while bed sediment pesticide concentrations correlated with the distance from potential sources. Fungicides and insecticides were detected frequently in fish and invertebrates collected near the mouth of the estuary and the contaminant profiles differed from the sediment and water collected. This is the first study to document the occurrence of many current-use pesticides, including fungicides, in tissue. Limited information is available on the uptake, accumulation and effects of current-use pesticides on non-target organisms. Additional data are needed to understand the impacts of pesticides, especially in small agriculturally-dominated estuaries.

Smalling, Kelly L.; Kuivila, Kathryn M.; Orlando, James L.; Phillips, Bryn M.; Anderson, Brian S.; Siegler, Katie; Hunt, John W.; Hamilton, Mary

2013-01-01

163

Swept away by a turbidity current in Mendocino submarine canyon, California  

NASA Astrophysics Data System (ADS)

We present unique observations and measurements of a dilute turbidity current made with a remotely operated vehicle in 400 m water depth near the head of Mendocino Canyon, California. The flow had a two-layer structure with a thin (0.5 to 30 m), relatively dense (<0.04 vol %) and fast (up to ~1.7 m/s) wedge-shaped lower layer overlain by a thicker (up to 89 m) more dilute and slower current. The fast moving lower layer lagged the slow moving, dilute flow front by 14 min, which we infer resulted from the interaction of two initial pulses. The two layers were strongly coupled, and the sharp interface between the layers was characterized by a wave-like instability. This is the first field-scale data from a turbidity current to show (i) the complex dynamics of the head of a turbidity current and (ii) the presence of multiple layers within the same event.

Sumner, E. J.; Paull, C. K.

2014-11-01

164

Integrated climate/land use/hydrological change scenarios for assessing threats to ecosystem services on California rangelands  

NASA Astrophysics Data System (ADS)

In California there are over 18 million acres of rangelands in the Central Valley and the interior Coast Range, most of which are privately owned and managed for livestock production. Ranches provide extensive wildlife habitat and generate multiple ecosystem services that carry considerable market and non-market values. These rangelands are under pressure from urbanization and conversion to intensive agriculture, as well as from climate change that can alter the flow of these services. To understand the coupled and isolated impacts of land use and climate change on rangeland ecosystem services, we developed six spatially explicit (250 m) coupled climate/land use/hydrological change scenarios for the Central Valley and oak woodland regions of California consistent with three IPCC emission scenarios - A2, A1B and B1. Three land use land cover (LULC) change scenarios were each integrated with two downscaled global climate models (GCMs) (a warm, wet future and a hot, dry future) and related hydrologic data. We used these scenarios to quantify wildlife habitat, water supply (recharge potential and streamflow) and carbon sequestration on rangelands and to conduct an economic analysis associated with changes in these benefits. The USGS FOREcasting SCEnarios of land-use change model (FORE-SCE), which runs dynamically with downscaled GCM outputs, was used to generate maps of yearly LULC change for each scenario from 2006 to 2100. We used the USGS Basin Characterization Model (BCM), a regional water balance model, to generate change in runoff, recharge, and stream discharge based on land use change and climate change. Metrics derived from model outputs were generated at the landscape scale and for six case-study watersheds. At the landscape scale, over a quarter of the million acres set aside for conservation in the B1 scenario would otherwise be converted to agriculture in the A2 scenario, where temperatures increase by up to 4.5 °C compared to 1.3 °C in the B1 scenario. A comparison of two watersheds - Alameda Creek, an urbanized watershed, and Upper Stony Creek, impacted by intensified agriculture, demonstrates the relative contribution of urbanization and climate change to water supply. In Upper Stony Creek, where 24% of grassland is converted to agriculture in the A1B scenario, a hotter, dryer 4-year time period could lead to a 40% reduction in streamflow compared to present day. In Alameda Creek, for the same scenario, 47% of grassland is converted to urbanized lands and streamflow may increase by 11%, resulting in a recharge:runoff ratio of 0.26; though if urbanization does not take place, streamflow could decrease by 64% and the recharge:runoff ratio would be 1.2. Model outputs quantify the impact of urbanization on water supply and show the importance of soil storage capacity. Scenarios have applications for climate-smart conservation and land use planning by identifying outcomes associated with coupled future land use scenarios and more variable and extreme potential future climates.

Byrd, K. B.; Flint, L. E.; Casey, C. F.; Alvarez, P.; Sleeter, B. M.; Sohl, T.

2013-12-01

165

Depth-integrated estimates of ecosystem metabolism in a high-elevation lake (Emerald Lake, Sierra Nevada, California)  

E-print Network

of gross primary production (GPP), community respiration (CR), and net ecosystem production (NEP). DielDepth-integrated estimates of ecosystem metabolism in a high-elevation lake (Emerald Lake, Sierra of seasonal metabolism, especially in the autumn when the lake is mixing on a diel basis. Ecosystem metabolism

California at Santa Barbara, University of

166

CLIMATE CHANGE IMPACTS ON CALIFORNIA VEGETATION  

E-print Network

CLIMATE CHANGE IMPACTS ON CALIFORNIA VEGETATION: PHYSIOLOGY, LIFE HISTORY, AND ECOSYSTEM CHANGE A White Paper from the California Energy Commission's California Climate Change Center of the uncertainties with climate change effects on terrestrial ecosystems is understanding where transitions

167

Particulate ?15N in laminated marine sediments as a proxy for mixing between the California Undercurrent and the California Current: A proof of concept  

NASA Astrophysics Data System (ADS)

measurements of particulate ?15N in coastal marine laminated sediments provide a high-resolution proxy for fluctuations in the intensity of denitrification in the water column. In the eastern tropical North Pacific oxygen minimum zone, this denitrification signal is transported northward by the California Undercurrent, thus serving as a tracer of ocean circulation. This is verified through comparisons between salinity in the thermocline off Southern California (Santa Monica Basin) and the difference between ?15Nsed within age equivalent sediments from a southern (Pescadero Slope) and northern (Santa Monica Basin) site. Trends in this parameter, ??15Nsed, relate to Pacific Decadal Oscillation (PDO) phase changes between 1900 and 1990. We hypothesize that the decline in ??15Nsed during warm PDO phases is due to a strengthening of the California Undercurrent transporting 15N-enriched nitrate from the eastern tropical North Pacific northward. The deviation from this trend after 1990 suggests recent changes in circulation and/or California Current water nutrient biogeochemistry.

Tems, Caitlin E.; Berelson, William M.; Prokopenko, Maria G.

2015-01-01

168

MICROBIAL INDICATORS OF AQUATIC ECOSYSTEM CHANGE: CURRENT APPLICATIONS TO EUTROPHICATION STUDIES. (R828677C001)  

EPA Science Inventory

Human encroachment on aquatic ecosystems is increasing at an unprecedented rate. The impacts of human pollution and habitat alteration are most evident and of greatest concern at the microbial level, where a bulk of production and nutrient cycling takes place. Aquatic ecosyste...

169

EFFECTS OF BIODIVERSITY ON ECOSYSTEM FUNCTIONING: A CONSENSUS OF CURRENT KNOWLEDGE  

Microsoft Academic Search

Humans are altering the composition of biological communities through a variety of activities that increase rates of species invasions and species extinctions, at all scales, from local to global. These changes in components of the Earth's biodiversity cause concern for ethical and aesthetic reasons, but they also have a strong potential to alter ecosystem properties and the goods and services

D. U. Hooper; F. S. Chapin; J. J. Ewel; A. Hector; P. Inchausti; S. Lavorel; J. H. Lawton; D. M. Lodge; M. Loreau; S. Naeem; B. Schmid; H. Setälä; A. J. Symstad; J. Vandermeer; D. A. Wardle

2005-01-01

170

Towards a study of synoptic-scale variability of the California current system  

NASA Technical Reports Server (NTRS)

A West Coast satellite time series advisory group was established to consider the scientific rationale for the development of complete west coast time series of imagery of sea surface temperature (as derived by the Advanced Very High Resolution Radiometer on the NOAA polar orbiter, and near-surface phytoplankton pigment concentrations (as derived by the Coastal Zone Color Scanner on Nimbus 7). The scientific and data processing requirements for such time series are also considered. It is determined that such time series are essential if a number of scientific questions regarding the synoptic-scale dynamics of the California Current System are to be addressed. These questions concern both biological and physical processes.

1985-01-01

171

Trophic structure and diversity in rocky intertidal upwelling ecosystems: A comparison of community patterns across California, Chile, South Africa and New Zealand  

NASA Astrophysics Data System (ADS)

The Benguela, California, and Humboldt represent three of the major eastern boundary upwelling ecosystems in the world. Upwelling ecosystems are highly productive, and this productivity forms the base of the food chain, potentially leading to ecosystems similar in trophic structure and diversity among upwelling regions. Here we compare the biological and trophic structure of rocky intertidal communities in each of these major upwelling regions. Our comparison includes a fourth region, New Zealand, which spans a similar latitudinal range, and experiences intermittent upwelling. The influence of oceanographic conditions on these communities was evaluated by using the long-term mean and standard deviation of satellite-based sea surface temperature (SST). Large differences emerged in the taxonomic richness in each of these systems, with California as the most and the Humboldt as the least taxonomically rich. Across all regions, richness tended to decrease progressively from lower trophic levels (macrophytes) to higher trophic levels (carnivores), and richness was inversely correlated with the proportion of variance in SST contained in the seasonal cycle, suggesting that strongly seasonal, predictable environments are relatively low in diversity. The functional and trophic structures were remarkably similar across these four regions of the world. Macrophytes were slightly dominant over filter-feeders in terms of space occupancy in all regions except the Benguela. Densities of herbivorous grazers were greatest in California and Benguela and far outnumbered carnivore densities in all regions. Despite some similarities, the overall structure of the communities from these regions differed significantly supporting the hypothesis that the biological and ecological consequences of similar physical forcing mechanisms (e.g. upwelling) are likely to be context-dependent.

Blanchette, C. A.; Wieters, E. A.; Broitman, B. R.; Kinlan, B. P.; Schiel, D. R.

2009-12-01

172

Harmonic analysis of tides and tidal currents in South San Francisco Bay, California  

USGS Publications Warehouse

Water level observations from tide stations and current observations from current-meter moorings in South San Francisco Bay (South Bay), California have been harmonically analysed. At each tide station, 13 harmonic constituents have been computed by a least-squares regression without inference. Tides in South Bay are typically mixed; there is a phase lag of approximately 1 h and an amplification of 1??5 from north to south for a mean semi-diurnal tide. Because most of the current-meter records are between 14 and 29 days, only the five most important harmonics have been solved for east-west and north-south velocity components. The eccentricity of tidal-current ellipse is generally very small, which indicates that the tidal current in South Bay is strongly bidirectional. The analyses further show that the principal direction and the magnitude of tidal current are well correlated with the basin bathymetry. Patterns of Eulerian residual circulation deduced from the current-meter data show an anticlockwise gyre to the west and a clockwise gyre to the east of the main channel in the summer months due to the prevailing westerly wind. Opposite trends have been observed during winter when the wind was variable. ?? 1985.

Cheng, R.T.; Gartner, J.W.

1985-01-01

173

Climatic impacts on phenology in chaparral- and coastal sage scrub-dominated ecosystems in southern California using MODIS-derived time series  

NASA Astrophysics Data System (ADS)

Remote sensing monitoring of vegetation phenology can be an important tool for detecting the impacts of climate change on whole ecosystem functioning at local to regional scales. This study elucidates climate-phenology relations and the changes occurring in the phenology of both chaparral and coastal sage scrub-dominated ecosystems in southern California. Whole ecosystem phenology is monitored for the period 2001-2012 using the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) derived from MODIS MOD13Q1. Changes in phenology are assessed through a comparison of the time series with temperature, precipitation, and Palmer Drought Severity Index (PDSI) data and by computing time series phenology metrics. Overall we find that the vegetation index values have fluctuated around a stable mean for vegetation types for the entire time period. However, interannual variability is high, likely due to annual variations in climate. The most significant statistical correlation in chaparral ecosystems were found between NDVI and PDSI, indicating that chaparral phenology is likely driven by drought and soil water deficit at the multi-monthly timescale. However, coastal sage scrub correlations were highest between NDVI and temperature + precipitation combined with no time lag. This reflects a more immediate response by these shallow rooted and deciduous species. The start of the growing season in both plant communities occurred early in rainy years, and later in years with lower PDSI (drought-associated). This suggests that future predicted climate change in southern California may cause increased interannual variability in chaparral phenology cycles, with early initiation of the growing season occurring in years following large rain events, and later initiation in drought years. Coastal sage scrub-dominated areas will be less influenced by lower frequency, long-term drought, but more immediately affected by discrete precipitation events and timing.

Willis, K. S.; Gillespie, T.; Okin, G. S.; MacDonald, G. M.

2013-12-01

174

Trophic modeling of the Northern Humboldt Current Ecosystem, Part I: Comparing trophic linkages under La Niña and El Niño conditions  

NASA Astrophysics Data System (ADS)

The El Niño of 1997-98 was one of the strongest warming events of the past century; among many other effects, it impacted phytoplankton along the Peruvian coast by changing species composition and reducing biomass. While responses of the main fish resources to this natural perturbation are relatively well known, understanding the ecosystem response as a whole requires an ecotrophic multispecies approach. In this work, we construct trophic models of the Northern Humboldt Current Ecosystem (NHCE) and compare the La Niña (LN) years in 1995-96 with the El Niño (EN) years in 1997-98. The model area extends from 4°S-16°S and to 60 nm from the coast. The model consists of 32 functional groups of organisms and differs from previous trophic models of the Peruvian system through: (i) division of plankton into size classes to account for EN-associated changes and feeding preferences of small pelagic fish, (ii) increased division of demersal groups and separation of life history stages of hake, (iii) inclusion of mesopelagic fish, and (iv) incorporation of the jumbo squid ( Dosidicus gigas), which became abundant following EN. Results show that EN reduced the size and organization of energy flows of the NHCE, but the overall functioning (proportion of energy flows used for respiration, consumption by predators, detritus and export) of the ecosystem was maintained. The reduction of diatom biomass during EN forced omnivorous planktivorous fish to switch to a more zooplankton-dominated diet, raising their trophic level. Consequently, in the EN model the trophic level increased for several predatory groups (mackerel, other large pelagics, sea birds, pinnipeds) and for fishery catch. A high modeled biomass of macrozooplankton was needed to balance the consumption by planktivores, especially during EN condition when observed diatoms biomass diminished dramatically. Despite overall lower planktivorous fish catches, the higher primary production required-to-catch ratio implied a stronger ecological impact of the fishery and stresses the need for precautionary management of fisheries during and after EN. During EN energetic indicators such as the lower primary production/total biomass ratio suggest a more energetically efficient ecosystem, while reduced network indicators such as the cycling index and relative ascendency indicate of a less organized state of the ecosystem. Compared to previous trophic models of the NHCE we observed: (i) a shrinking of ecosystem size in term of energy flows, (ii) slight changes in overall functioning (proportion of energy flows used for respiration, consumption by predators and detritus), and (iii) the use of alternate pathways leading to a higher ecological impact of the fishery for planktivorous fish.

Tam, Jorge; Taylor, Marc H.; Blaskovic, Verónica; Espinoza, Pepe; Michael Ballón, R.; Díaz, Erich; Wosnitza-Mendo, Claudia; Argüelles, Juan; Purca, Sara; Ayón, Patricia; Quipuzcoa, Luis; Gutiérrez, Dimitri; Goya, Elisa; Ochoa, Noemí; Wolff, Matthias

2008-10-01

175

Ecosystem consequences of changing inputs of terrestrial dissolved organic matter to lakes: current knowledge and future challenges  

USGS Publications Warehouse

Lake ecosystems and the services that they provide to people are profoundly influenced by dissolved organic matter derived from terrestrial plant tissues. These terrestrial dissolved organic matter (tDOM) inputs to lakes have changed substantially in recent decades, and will likely continue to change. In this paper, we first briefly review the substantial literature describing tDOM effects on lakes and ongoing changes in tDOM inputs. We then identify and provide examples of four major challenges which limit predictions about the implications of tDOM change for lakes, as follows: First, it is currently difficult to forecast future tDOM inputs for particular lakes or lake regions. Second, tDOM influences ecosystems via complex, interacting, physical-chemical-biological effects and our holistic understanding of those effects is still rudimentary. Third, non-linearities and thresholds in relationships between tDOM inputs and ecosystem processes have not been well described. Fourth, much understanding of tDOM effects is built on comparative studies across space that may not capture likely responses through time. We conclude by identifying research approaches that may be important for overcoming those challenges in order to provide policy- and management-relevant predictions about the implications of changing tDOM inputs for lakes.

Solomon, Christopher T.; Jones, Stuart E.; Weidel, Brian C.; Buffam, Ishi; Fork, Megan L; Karlsson, Jan; Larsen, Soren; Lennon, Jay T.; Read, Jordan S.; Sadro, Steven; Saros, Jasmine E.

2015-01-01

176

Ecosystem scenarios shape fishermen spatial behavior. The case of the Peruvian anchovy fishery in the Northern Humboldt Current System  

NASA Astrophysics Data System (ADS)

A major goal in marine ecology is the understanding of the interactions between the dynamics of the different ecosystem components, from physics to top predators. While fishermen are among the main top predators at sea, almost none of the existing studies on ecology from physics to top predators contemplate fishermen as part of the system. The present work focuses on the coastal processes in the Northern Humboldt Current System, which encompasses both an intense climatic variability and the largest monospecific fishery of the world. From concomitant satellite, acoustic survey and Vessel Monitoring System data (?90,000 fishing trips) for a ten-year period (2000-2009), we quantify the associations between the dynamics of the spatial behavior of fishermen, environmental conditions and anchovy (Engraulis ringens) biomass and spatial distribution. Using multivariate statistical analyses we show that environmental and anchovy conditions do significantly shape fishermen spatial behavior and present evidences that environmental fluctuations smoothed out along trophic levels. We propose a retrospective analysis of the study period in the light of the ecosystem scenarios evidenced and we finally discuss the potential use of fishermen spatial behavior as ecosystem indicator.

Joo, Rocio; Bertrand, Arnaud; Bouchon, Marilu; Chaigneau, Alexis; Demarcq, Hervé; Tam, Jorge; Simier, Monique; Gutiérrez, Dimitri; Gutiérrez, Mariano; Segura, Marceliano; Fablet, Ronan; Bertrand, Sophie

2014-11-01

177

Observed and modeled tsunami current velocities in Humboldt Bay and Crescent City Harbor, northern California  

NASA Astrophysics Data System (ADS)

A pilot project was initiated in 2009 in Humboldt Bay, about 370 kilometers (km) north of San Francisco, California, to measure the currents produced by tsunamis. Northern California is susceptible to both near- and far-field tsunamis and has a historic record of damaging events. Crescent City Harbor, located approximately 100 km north of Humboldt Bay, suffered US 20 million in damages from strong currents produced by the 2006 Kuril Islands tsunami and an additional US 20 million from the 2011 Japan tsunami. In order to better evaluate these currents in northern California, we deployed a Nortek Aquadopp 600kHz 2D Acoustic Doppler Current Profiler (ADCP) with a one-minute sampling interval in Humboldt Bay, near the existing National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) tide gauge station. The instrument recorded the tsunamis produced by the Mw 8.8 Chile earthquake on February 27, 2010 and the Mw 9.0 Japan earthquake on March 11, 2011. Currents from the 2010 tsunami persisted in Humboldt Bay for at least 30 hours with peak amplitudes of about 0.3 meters per second (m/s). The 2011 tsunami signal lasted for over 86 hours with peak amplitude of 0.95 m/s. Strongest currents corresponded to the maximum change in water level as recorded on the NOAA NOS tide gauge, and occurred 90 minutes after the initial wave arrival. No damage was observed in Humboldt Bay for either event. In Crescent City, currents for the first three and a half hours of the 2011 Japan tsunami were estimated using security camera video footage from the Harbor Master building across from the entrance to the small boat basin, approximately 70 meters away from the NOAA NOS tide gauge station. The largest amplitude tide gauge water-level oscillations and most of the damage occurred within this time window. The currents reached a velocity of approximately 4.5 m/s and six cycles exceeded 3 m/s during this period. Measured current velocities both in Humboldt Bay and in Crescent City were compared to calculated velocities from the Method of Splitting Tsunamis (MOST) numerical model. For Humboldt Bay, the 2010 model tsunami frequencies matched the actual values for the first two hours after the initial arrival however the amplitudes were underestimated by approximately 65%. MOST replicated the first four hours of the 2011 tsunami signal in Humboldt Bay quite well although the peak flood currents were underestimated by about 50%. MOST predicted attenuation of the signal after four hours but the actual signal persisted at a nearly constant level for more than 48 hours. In Crescent City, the model prediction of the 2011 frequency agreed quite well with the observed signal for the first two and a half hours after the initial arrival with a 50% underestimation of the peak amplitude. The results from this project demonstrate that ADCPs can effectively record tsunami currents for small to moderate events and can be used to calibrate and validate models (i.e. MOST) in order to better predict hazardous tsunami conditions and improve planned responses to protect lives and property, especially within harbors. An ADCP will be installed in Crescent City Harbor and four additional ADCPs are being deployed in Humboldt Bay during the fall of 2012.

Admire, A. R.; Dengler, L.; Crawford, G. B.; uslu, B. U.; Montoya, J.

2012-12-01

178

Remote versus local influence of ENSO on the California Current System  

NASA Astrophysics Data System (ADS)

Much of the observed interannual variability in the physical and biogeochemical state of the California Current System (CalCS) is associated with El Niño Southern Oscillation. Yet it is unclear whether this is primarily a result of atmospheric teleconnections forcing the ocean locally through changes in wind and fluxes of heat and freshwater, or whether this is a consequence of oceanic interior processes that transport tropical variability through, e.g., coastally trapped waves to the region. Here we investigate the relative contribution of these two mechanisms in the CalCS using a novel setup of the Regional Oceanic Modeling System coupled to a biogeochemical/ecological model. We conducted a hindcast simulation over the period 1979-2013 and contrast the results with those from sensitivity simulations with climatological atmospheric boundary conditions either for the U.S. West Coast or the rest of the Pacific. We find that remote forcing dominates the variability of the physical state in the nearshore region of the CalCS, explaining up to 80% of monthly mean sea-surface height and temperature variability. In contrast, local processes tend to drive variations in the biogeochemical/ecological state, particularly along central and northern California, explaining up to 50% of the observed surface variability. Most of the remote forcing is a consequence of coastally trapped waves that travel northward at speeds of approximately 230 km d-1, and thereby alter sea-level height, thermocline structure, and upwelling along California. Biogeochemically active tracers respond to this remote forcing as well, especially at depth, but are more strongly modulated by local atmospheric forcing, especially variations in upwelling-favorable winds.

Frischknecht, M.; Münnich, M.; Gruber, N.

2015-02-01

179

Sardine and anchovy spawning as related to temperature and upwelling in the California current system  

SciTech Connect

Sardine and anchovy spawning was analyzed regarding its relation to sea-surface temperature and upwelling, using CalCOFI cruise data and Bakun's upwelling indices. Previous reports of temperature ranges for sardine and anchovy spawning have not taken into account the distribution of SST and have mostly referenced the cooler spawning area of the species. By obtaining the proportion of positive stations to total sampled stations for each tenth of a degree Celsius in the SST distribution, the authors were able to discriminate the ranges of preferred temperatures of spawning for both species. Sardines spawn in a much wider temperature range (13-25C) than anchovy (11.5-16.5C). Two maxima of spawning occur in the California Current: at 15C and 23C. An additional peak is present in the Gulf of California at about 19C. Only one maximum is evident for anchovy spawning, at about 14C. The distribution of spawning as a function of upwelling was also analyzed for both species. There is a maximum for sardines at intermediate values of upwelling. There are two maxima for anchovy: a minor one at low levels of upwelling and a major one at the maximum values of upwelling. They conclude that sardines are eurythermic as compared to anchovies, but spawn only at intermediate values of upwelling, whereas anchovies are stenothermic but spawn at much wider ranges of upwelling, particularly at low and high values. The differences suggest exclusive competition, but more detailed analyses are needed.

Lluch-Belda, D.; Lluch-Cota, D.B.; Hernandez-Vazquez, S.H.; Salinas-Zavala, C.A. (Centro de Investigaciones Biologicas de Baja California Sur, A.C., (Mexico)); Schwartzlose, R.A. (Univ. of California, La Jolla (United States))

1991-11-01

180

Constraining the timing of turbidity current driven sediment transport down Monterey Canyon, offshore California  

NASA Astrophysics Data System (ADS)

Turbidity currents are responsible for transport of sand down the Monterey Submarine Canyon, offshore California, from the shoreline to Monterey Fan. However the timing of sediment transport events and their frequencies are not fully understood despite recent monitoring of canyon events and AMS 14C dating of foraminifera from hemipelagic sediments bracketing sand deposited during turbidity flows. Quartz optically stimulated luminescence (OSL) dating in sand sequences provides a complementary means of dating sand transport. OSL dates reflect the time interval since the sand grains were last exposed to sunlight. However, the technique has never been applied extensively to canyon sediments before. Here we report both quartz OSL ages of sand deposits and benthic foraminifera ages sampled from the axial channel within Monterey Submarine Canyon and Fan via ROV-collected vibracores. This allows a rare opportunity to directly test the frequency and timing of turbidity current events at different points in the canyon. We use both single-grain and small (~2 mm area) single aliquot regeneration OSL approaches on vibracore samples from various water depths to determine sand transport frequency. Within the upper canyon (<2,000 m water depths) the OSL data require sub-decadal to decadal transit times. Sand bearing fining upward sequences yielding middle Holocene to last few hundred year ages indicate turbidity currents occur at 150 to 250 year event frequencies within the fan channel out to 3,600 m water depth. We suggest that turbidity currents have been active during the current sea-level high stand and that the submarine fan has recorded turbidity currents over the entire Holocene. The increased age spread in single grain OSL dates with water depth provides evidence of sediment mixing and reworking during turbidity flows. Apparently, sand is stored within the canyon for various amounts of time while it is in route to its current location on the fan.

McGann, M.; Stevens, T.; Paull, C. K.; Ussler, W.; Buylaert, J.

2013-12-01

181

Is tourism damaging ecosystems in the Andes? Current knowledge and an agenda for future research.  

PubMed

Despite the popularity of tourism and recreation in the Andes in South America and the regions conservation value, there is limited research on the ecological impacts of these types of anthropogenic use. Using a systematic quantitative literature review method, we found 47 recreation ecology studies from the Andes, 25 of which used an experimental design. Most of these were from the Southern Andes in Argentina (13 studies) or Chile (eight studies) with only four studies from the Northern Andes. These studies documented a range of impacts on vegetation, birds and mammals; including changes in plant species richness, composition and vegetation cover and the tolerance of wildlife of visitor use. There was little research on the impacts of visitors on soils and aquatic systems and for some ecoregions in the Andes. We identify research priorities across the region that will enhance management strategies to minimise visitor impacts in Andean ecosystems. PMID:25201299

Barros, Agustina; Monz, Christopher; Pickering, Catherine

2015-03-01

182

MULTILOCUS SIMPLE SEQUENCE REPEATS AND SINGLE NUCLEOTIDE POLYMORPHISM MARKERS FOR GENOTYPING AND ASSESSING GENETIC DIVERSITY OF XYLELLA FASTIDIOSA IN CALIFORNIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

To develop effective disease management strategies, we need to understand population structure and genetic diversity of pathogens in agricultural ecosystems. Current information regarding population structure and genetic diversity of Xylella fastidiosa (Xf) in California is insufficient to adequate...

183

Rapid formation of hyperpycnal sediment gravity currents offshore of a semi-arid California river  

NASA Astrophysics Data System (ADS)

Observations of sediment dispersal from the Santa Clara River of southern California during two moderately sized river discharge events suggest that river sediment rapidly formed a negatively buoyant (hyperpycnal) bottom plume along the seabed within hours of peak discharge. An array of acoustic and optical sensors were placed at three stations 1 km from the Santa Clara River mouth in 10-m water depth during January-February 2004. These combined observations suggest that fluid mud concentrations of suspended sediment (>10 g/l) and across-shore gravity currents (˜5 cm/s) were observed in the lower 20-40 cm of the water column 4-6 h after discharge events. Gravity currents were wave dominated, rather than auto-suspending, and appeared to consist of silt-to-clay sized sediment from the river. Sediment mass balances suggest that 25-50% of the discharged river sediment was transported by these hyperpycnal currents. Sediment settling purely by flocs (˜1 mm/s) cannot explain the formation of the observed hyperpycnal plumes, therefore we suggest that some enhanced sediment settling from mixing, convective instabilities, or diverging plumes occurred that would explain the formation of the gravity currents. These combined results provide field evidence that high suspended-sediment concentrations from rivers (>1 g/l) may rapidly form hyperpycnal sediment gravity currents immediately offshore of river mouths, and these pathways can explain a significant portion of the river-margin sediment budget. The fate of this sediment will be strongly influenced by bathymetry, whereas the fate of the remaining sediment will be much more influenced by ocean currents.

Warrick, Jonathan A.; Xu, Jingping; Noble, Marlene A.; Lee, Homa J.

2008-05-01

184

An evaluation of the latitudinal gradient of chlorophyll in the California Current  

NASA Astrophysics Data System (ADS)

Tracking of spatial and temporal trends in phytoplankton abundance and distribution is an important step toward understanding large-scale macroecological processes in the ocean. Measurements of ocean radiance from satellite-borne sensors, such as SeaWiFS and MODIS, can be used to estimate surface chlorophyll concentration, which is a good indicator of phytoplankton biomass. The primary goal of this study was to evaluate the latitudinal gradient in chlorophyll concentration within the California Current first reported by Ware and Thomson (2005). They found that average chlorophyll concentration tended to increase steadily from 32-48°N latitude. This concentration gradient was reevaluated using a longer dataset and an algorithm refined for the region. Radiance data from the MODIS-Aqua instrument were obtained for every year from 2002 through 2013. Data included annual averages of remote sensing radiance as well as monthly averages for February, April, and August. These months were chosen to represent each of the three oceanographic seasons present in the California Current. Estimates of chlorophyll concentration were derived from these data using the CALFIT algorithm developed by Kahru et al. (2012). The resulting maps of chlorophyll concentration were processed in MATLAB and linear regressions were performed using SYSTAT 13 software. A statistically significant (p < 0.05) latitudinal trend in chlorophyll was observed in the annual averaged data as well as in the averaged seasonal data from February and August. No significant trend was observed in the averaged April data. Chlorophyll concentration was positively correlated with latitude in every instance, except in April 2003 and April 2005, where a negative correlation was observed. The positive latitudinal trend was strongest during August and weakest during April. Strong peaks in chlorophyll were observed near San Francisco Bay and the mouth of the Columbia River, suggesting that river-borne nutrient input may be the dominant factor responsible for the existence of this chlorophyll gradient.

Dietrich, W.; Broughton, J.; Kudela, R. M.

2013-12-01

185

Invasive Plant-Soil Feedbacks and Ecosystem Resistance and Resilience: A Comparison of Three Vegetation Types in California  

E-print Network

potential soil respiration where weed/seed plots had greatlyPotential soil respiration of the weed/seed treatment wasseed treatments 2008 and 09 (P = 0.070, P = 0.002). Ecosystem Function Potential soil respiration

Dickens, Sara Jo Myrtle

2010-01-01

186

Differences in dynamic response of California Current salmon species to changes in ocean conditions  

NASA Astrophysics Data System (ADS)

While changes in the northeast Pacific Ocean in the mid-1970s apparently caused changes in salmon population growth in the Gulf of Alaska and the California Current, the responses of California Current salmon species, coho salmon ( Oncorhynchus kisutch) and chinook salmon ( O. tshawytscha) differed. Coho salmon catches declined dramatically along the coasts of California, Oregon and Washington, while chinook salmon catches did not. This provides an opportunity for comparative analysis, a rarity in the study of long-term changes in the ocean. Here we test one possible explanation for that difference, that chinook salmon populations are inherently more persistent because chinook salmon populations spawn over a range of ages, while coho salmon spawn predominantly at age 3 yr. We extended a previous theoretical approach that had been used to assess the long-term response of salmon populations with various spawning age structures to different means and variances in environmental variability. New results indicate that populations with environmental variability at the age of return to freshwater have the same characteristic identified earlier for populations with variability in the age of entry: populations spawning at multiple ages are more persistent, but that increased persistence is gained in the first few percent of departure from all spawning at a single age. Thus, in both cases the results are too sensitive to values of uncertain parameters to depend on as an explanation of the differences in response. We also approached this question by subjecting model populations with coho and chinook salmon spawning age structures to an empirical estimate of actual marine survival of coho salmon over the years 1970-2002, asking the question, if chinook salmon had been subjected to the same ocean survivals would they have experienced the same decline. The differences in spawning age structure made little difference in population responses. The dominant factor influencing the response of these species to a decline in ocean survival was the behavior of the freshwater spawner/smolt relationship at low abundance, a factor that has recently been intensively studied for coho salmon, but is poorly known for chinook salmon. These results suggest that the GLOBEC NEP should focus attention on the ocean phase of salmon life, to explain the observed difference in population response to changes in physical conditions.

Botsford, Louis W.; Lawrence, Cathryn A.; Forrest Hill, M.

2005-01-01

187

Controls on the fate, structure and function of dissolved organic carbon and nitrogen in a California grassland, oak woodland and conifer ecosystem  

NASA Astrophysics Data System (ADS)

In California, oak woodlands and grasslands, have been expanding their geographic range over the past 100 years, and are projected to extend upward along the western slopes of the Sierra Nevada foothills in response to climate change. Since vegetation type plays a large role in soil formation and carbon (C) and nitrogen (N) cycling, shifts in vegetation distribution could impact C and N storage and processing. This study was designed to determine if dissolved organic carbon (DOC) and nitrogen (DON) production, composition, biodegradation and sorption in the mineral soil of a grassland, oak woodland and conifer ecosystem is related to the type of plant material from which it is derived and how these processes are correlated with temperature. A field experiment where leachates from transplanted soil columns were collected over two rainy seasons at a grassland, oak woodland and conifer field location was combined with laboratory batch adsorption and biodegradation using litter and soil from the same sites. Specific ultra-violet absorbance at 254 nm (SUVA 254), 13C nuclear magnetic resonance (13C NMR) and fractionation of dissolved organic matter (DOM) into hydrophilic and hydrophobic factions was used to determine the structural composition of the DOC solutions. In the laboratory, surface litter from the grass, oak and a conifer site were incubated with de-ionized water for 5, 15 or 96 hours at 4, 20 or 30oC. Incubation time had little effect on DOC structure while vegetation type and temperature had significant effects on DOC functional groups. Increased incubation time and temperature significantly increased DOC and DON concentration. Percent biodegradable DOC was positively correlated to increasing heteroaliphatic functional groups. Since grass, oak and pine DOM solutions had the highest levels of biodegradation using soil inoculums from the sites where the surface litter originated, biodegradation appears to be related to site microbial activity. In batch adsorption studies, an increase in incubation temperature is related to an increase in sorption and biodegradation. There were no significant correlations between adsorption and DOC functional groups. Soil iron and aluminum content were found to play a larger role in DOC adsorption than DOC functional group concentration. Therefore, sorption appears to be primarily controlled by ecosystem soil characteristics and a thermodynamic relationship with temperature rather than surface litter type. In the field experiment, neither DOC, DON nor SUVA 254 values of column leachates differed significantly with surface litter or soil type. However, the 15 month incubation of the soil columns containing all three soil types at all three field locations resulted in several significant changes in soil C and N parameters. Percent C, water extractable DOC and soil C:N all increased in the soil from the pine location that was incubated at the oak and grass location. These changes indicate that the soils at mixed conifer sites in the Sierra Nevada foothills could store increased levels of soil C if grassland and oak woodland vegetation shift into the areas currently dominated by mixed conifers.

Pittiglio, S. L.; Zasoski, R.

2010-12-01

188

FOOD AND FEEDING OF LARVAE OF THREE FISHES OCCURRING IN THE CALIFORNIA CURRENT, SARDZNOPS SAGAX, ENGRAULIS MORDAX, AND TRACHURUS SYMMETRICUS  

Microsoft Academic Search

The size, number, and types of food particles eaten by larvae of Pacific sardine, Sardinops sagax; northern anchovy, Engraulis mor&; and jack mackerel, Trachurus symmetricus, were determined by an examination of gut contents of larvae captured in plankton samples from the California Current. Food particles found in larvae of the three fishes were predominantly the eggs, nauplii, and the copepodid

DAVID K. ARTHUR

189

Evolution of chemical, biological, and physical water properties in the northern California Current in 2005: Remote or local wind forcing?  

Microsoft Academic Search

The spring onset of persistent upwelling-favorable winds was later than usual in the northern California Current system in 2005, resulting in delayed provision of inorganic nutrients to the upper waters of the coastal ocean. This study uses water column measurements to illustrate the evolution of temperature, salinity, nitrate and chlorophyll a prior to and after the onset of persistent local

B. Hickey; A. MacFadyen; W. Cochlan; R. Kudela; K. Bruland; C. Trick

2006-01-01

190

Continuous assimilation of Geosat altimetric sea level observations into a numerical synoptic ocean model of the California Current  

Microsoft Academic Search

In this study, real Geosat altimeter sea level observations for the 1-year period extending from January to December 1987 were assimilated into a realistic wind-driven numerical synoptic ocean model of the California Current. The objective was to evaluate the effectiveness of using a realistic synoptic ocean model to interpolate (dynamically) real altimeter sea level observations from the Geosat ERM onto

Warren B. White; Chang-Kou Tai; William R. Holland

1990-01-01

191

Continuous assimilation of Geosat altimetric sea level observations into a numerical synoptic ocean model of the California current  

Microsoft Academic Search

In this study, real Geosat altimetric sea level observations for the 1-year period extending from January to December 1987 were assimilated into a realistic wind-driven numerical synoptic ocean model of the California Current. The objective was to evaluate the effectiveness of using a realistic synoptic ocean model to interpolate (dynamically) real altimetric sea level observations from the Geosat ERM onto

Warren B. White; Chang-Kou Tai; William R. Holland

1990-01-01

192

Estimating the impacts of fishing on dependent predators: a case study in the California Current.  

PubMed

Juvenile rockfish (Sebastes spp.) are important prey to seabirds in the California Current System, particularly during the breeding season. Both seabird breeding success and the abundance of pelagic juvenile rockfish show high interannual variability. This covariation is largely a response to variable ocean conditions; however, fishing on adult rockfish may have had consequences for seabird productivity (e.g., the number of chicks fledged per breeding pair) by reducing the availability of juvenile rockfish to provisioning seabird parents. We tested the hypothesis that fishing has decreased juvenile rockfish availability and thereby limited seabird productivity over the past 30 years. We quantified relationships between observed juvenile rockfish relative abundance and seabird productivity, used fisheries stock assessment approaches to estimate the relative abundance of juvenile rockfish in the absence of fishing, and compared the differences in seabird productivity that would have resulted without rockfish fisheries. We examined the abundance of juvenile rockfish and the corresponding productivity of three seabird species breeding on Southeast Farallon Island (near San Francisco, California, USA) from the early 1980s to the present. Results show that while the relative abundance of juvenile rockfish has declined to approximately 50% of the estimated unfished biomass, seabirds achieved 75-95% of the estimated un-impacted levels of productivity, depending upon the species of bird and various model assumptions. These results primarily reflect seabirds with "conservative" life histories (one egg laid per year) and may be different for species with more flexible life history strategies (greater reproductive effort). Our results are consistent with the premise that the impacts of local rockfish fisheries on seabird productivity are less than impacts that have occurred to the prey resources themselves due to ocean climate and the ability of seabirds to buffer against changes in prey availability through prey-switching and other behavioral mechanisms. PMID:21265453

Field, J C; MacCall, A D; Bradley, R W; Sydeman, W J

2010-12-01

193

Wind-driven variability in sea surface temperature front distribution in the California Current System  

NASA Astrophysics Data System (ADS)

Simultaneous satellite-derived observations from 2002 to 2009 are used to quantify the relation between sea surface temperature (SST) fronts and ocean winds in the California Current System (CCS). An edge-detection algorithm is applied to SST observations to generate monthly maps of frontal probabilities. Empirical orthogonal decompositions reveal that the seasonal evolution of fronts in the CCS is strongly related to the seasonal evolution of coastal alongshore wind stress. The seasonal development of SST fronts is remarkably different to the north and to the south of Cape Mendocino, however. While fronts to the north of the cape extend for hundreds of kilometers from the coast peaking during summer and fall, when upwelling winds are stronger off northern California and Oregon, the region to the south of Cape Mendocino is characterized by high frontal activity during spring in a much narrower band close to the coast. Throughout the region, anomalies in the intensity of upwelling-favorable wind stress are followed by anomalies in frontal activity. The width and speed of the widening of the region of high frontal activity are also related to coastal alongshore wind stress. Interannual variability in the timing of the widening of the region of high frontal activity in the lee of Cape Blanco compared to the timing of the spring transition to upwelling-favorable winds may be related to the wind stress curl distribution in the lee of the cape. Stronger upwelling-favorable wind stress curl anomalies lead to early widening of the region of high frontal activity.

Castelao, Renato M.; Wang, Yuntao

2014-03-01

194

Air-sea exchange of CO2 at a Northern California coastal site along the California Current upwelling system  

NASA Astrophysics Data System (ADS)

Uncertainty in the air-sea CO2 exchange (CO2 flux) in coastal upwelling zones is attributed to high temporal variability, which is caused by changes in ocean currents. Upwelling transports heterotrophic, CO2 enriched water to the surface and releases CO2 to the atmosphere, whereas the presence of nutrient-rich water at the surface supports high primary production and atmospheric CO2 uptake. To quantify the effects of upwelling on CO2 fluxes, we measured CO2 flux at a coastal upwelling site off of Bodega Bay, California, during the summer of 2007 and the fall of 2008 using the eddy covariance technique and the bulk method with pCO2 measurements from November 2010 to July 2011. Variations in sea surface temperatures (SST) and alongshore wind speeds suggest that the measurement period in 2007 coincided with a typical early-summer upwelling period and the measurement period in 2008 was during a typical fall relaxation period. A strong source of CO2 (~1.5 ± 7 SD (standard deviation) g C m-2 day-1) from the ocean to the atmosphere during the upwelling period was concurrent with high salinity, low SST, and low chlorophyll density. In contrast, a weak source of CO2 flux (~0.2 ± 3 SD g C m-2 day-1) was observed with low salinity, high SST and high chlorophyll density during the relaxation period. Similarly, the sink and source balance of CO2flux was highly related to salinity and SST during the pCO2 measurement periods; high salinity and low SST corresponded to high pCO2, and vice versa. We estimated that the coastal area off Bodega Bay was likely a source of CO2 to the atmosphere based on the following conclusions: (1) the overall CO2 flux estimated from both eddy covariance and pCO2 measurements showed a source of CO2; (2) although the relaxation period during the 2008 measurements were favorable to CO2 uptake, CO2 flux during this period was still a slight source, (3) salinity and SST were found to be good predictors of the CO2 flux for both eddy covariance and pCO2 measurements, and historical data of daily averaged SST and salinity between 1988 to 2011 show that 99% of the data falls within the range of our observation in May-June 2007, August-September 2008 and November 2010-July 2011 indicating that our data set was representative of the annual variations in the sea state. Based on the developed relationship between pCO2 and SST and salinity, the average annual CO2 flux between 1988 and 2011 was estimated to be ~35 mol C m-2 yr-1. The peak monthly CO2 flux of ~7 mol C m-2 month-1 accounted for about 30% of the dissolved inorganic carbon in the surface mixed-layer.

Ikawa, H.; Faloona, I.; Kochendorfer, J.; Paw U, K. T.; Oechel, W. C.

2012-12-01

195

Springtime distributions of migratory marine birds in the southern California Current: Oceanic eddy associations and coastal habitat hotspots over 17 years  

Microsoft Academic Search

We used a 17-year time series of shipboard observations to address the hypothesis that marine birds associate with persistent hydrographic features in the southern California Current System (CCS). Overall, approximately 27,000 km of ocean habitat were surveyed, averaging 1600 km per cruise. We identified mesoscale features (eddy centers and the core of the California Current), based on dynamic height anomalies,

P. P. W. Yen; W. J. Sydeman; S. J. Bograd; K. D. Hyrenbach

2006-01-01

196

Top-down and bottom-up factors affecting seabird population trends in the California current system (1985-2006)  

NASA Astrophysics Data System (ADS)

To characterize the environmental factors affecting seabird population trends in the central portion of the California current system (CCS), we analyzed standardized vessel-based surveys collected during the late spring (May-June) upwelling season over 22 yr (1985-2006). We tested the working hypothesis that population trends are related to species-specific foraging ecology, and predicted that temporal variation in population size should be most extreme in diving species with higher energy expenditure during foraging. We related variation in individual species abundance (number km -2) to seasonally lagged (late winter, early spring, late spring) and concurrent ocean conditions, and to long-term trends (using a proxy variable: year) during a multi-decadal period of major fluctuations in the El Niño-Southern oscillation (ENSO) and the Pacific decadal oscillation (PDO). We considered both remote (Multivariate ENSO Index, PDO) and local (coastal upwelling indices and sea-surface temperature) environmental variables as proxies for ocean productivity and prey availability. We also related seabird trends to those of potentially major trophic competitors, humpback ( Megaptera novaeangliae) and blue ( Balaenoptera musculus) whales, which increased in number 4-5-fold midway during our study. Cyclical oscillations in seabird abundance were apparent in the black-footed albatross ( Phoebastria nigripes), and decreasing trends were documented for ashy storm-petrel ( Oceanodroma homochroa), pigeon guillemot ( Cepphus columbus), rhinoceros auklet ( Cerorhinca monocerata), Cassin’s auklet ( Ptychoramphus aleuticus), and western gull ( Larus occidentalis); the sooty shearwater ( Puffinus griseus), exhibited a marked decline before signs of recovery at the end of the study period. The abundance of nine other focal species varied with ocean conditions, but without decadal or long-term trends. Six of these species have the largest global populations in the CCS, and four are highly energetic, diving foragers. Furthermore, three of the diving species trends were negatively correlated with the abundance of humpback whales in the study area, a direct competitor for the same prey. Therefore, on the basis of literature reviewed, we hypothesize that the seabirds were affected by the decreasing carrying capacity of the CCS, over-exploitation of some prey stocks and interference competition from the previously exploited, but now increasing, baleen whale populations. Overall, our study highlights the complexity of the ecological factors driving seabird population trends in the highly variable and rapidly changing CCS ecosystem.

Ainley, David G.; David Hyrenbach, K.

2010-03-01

197

Current status and historical trends of organochlorine pesticides in the ecosystem of Deep Bay, South China  

Microsoft Academic Search

To characterize the current status and historical trends in organochlorine pesticides (OCPs) contamination in Deep Bay, an important water body between Hong Kong and mainland China with a Ramsar mangrove wetland (Maipo), samples from seawater, suspended particulate matter (SPM), surface sediment, sediment core and fish were collected to determine the OCPs concentrations. Sediment core dating was accomplished using the 210Pb

Yao-Wen Qiu; Gan Zhang; Ling-Li Guo; Hai-Rong Cheng; Wen-Xiong Wang; Xiang-Dong Li; Onyx W. H. Wai

2009-01-01

198

Marine Ecosystems  

NSDL National Science Digital Library

Marine ecosystem introduction to shorelines, temperate oceans, and tropical oceans. Shoreline topics cover sandy and rocky shores, barrier islands, tide pools, estuaries, salt marshes, mud flats, mangrove forests, tides, waves, currents, and shoreline animals. Students can learn about temperate ocean zonation, light, forests, patterns, and animals. The tropical oceans chapter features coral reefs and tropical ocean animals. This site would provide a comprehensive introduction for a marine ecosystems or an ocean science unit.

199

Comparison of Strong Currents and Impacts on the California (USA) Maritime Communities from the 2010 Chile and 2011 Japan Teletsunamis  

NASA Astrophysics Data System (ADS)

The February 27, 2010 Chile and March 11, 2011 Japan tsunamis caused dramatic loss of life and damage in the near-source region, and notable impacts in distant coastal regions like California. Comprehensive post-tsunami surveys and the availability of hundreds of videos within harbors and marinas allow for detailed documentation of these two events by the State of California Tsunami Program. Although neither event caused significant inundation of dry land in California because peak arrival occurred during low tide, damage to docks, harbor infrastructure, and boats was noteworthy. The 2010 Chile tsunami caused approximately 3-million in damage to a dozen harbors, primarily in central and southern California locations like Santa Cruz Harbor, Ventura Harbor and San Diego Bay. The 2011 Japan tsunami caused over 50-million in damage to more than two dozen harbors along the entire coast of California, most extensively to harbors/marinas in Crescent City, Noyo River, and Santa Cruz. During both events, strong tsunami currents, with some observed estimates greater than 15 knots, were generated at harbor entrances and along inside bends and narrows within harbors. Preliminary evaluations of harbor infrastructure and the interaction of boats indicate that drag along the base of large ships exacerbated the damage to docks to which the ships were tied. Evaluation of tsunami currents and damage will help in the validation/calibration of numerical tsunami model currents with the ultimate goal of developing tsunami current hazard maps for harbors statewide. These hazard maps will improve emergency response and infrastructure planning within harbors.

Wilson, R. I.; Miller, K.; Davenport, C.; Nicolini, T.; Dengler, L.; Admire, A. R.; Synolakis, C.; Barberopoulou, A.; Borrero, J. C.; Lynett, P. J.; Jaffe, B. E.; Curtis, E.

2011-12-01

200

Multi-Objective Analysis for Ecosystem Reconciliation on an Engineered Floodplain: The Yolo Bypass in California's Central Valley  

E-print Network

by restoring natural hydrologic and successional processes. However levees, dams, and development prevent conservation and restoration (Keddy et al. 2009, Bayley 1995, Welcomme 2008). On the west coast of the United States, and California in particular, studies have noted the special roles of floodplains in the life

Pasternack, Gregory B.

201

Zooplankton Distribution and Transport in the California Current off Oregon4 , Zhou M.1*  

E-print Network

resolution28 measurements of temperature, salinity, depth, fluorescence and zooplankton29 abundance contributes significantly to biomass losses in46 shelf ecosystems and in turn fuels offshelf ecosystems.47 #12 revealed that the intensive offshore jets associated with53 cold filaments penetrated more than 100 m deep

Pierce, Stephen

202

Changes in production and respiration during a spring phytoplankton bloom in San Francisco Bay, California, USA: Implications for net ecosystem metabolism  

USGS Publications Warehouse

We present results of an intensive sampling program designed to measure weekly changes in ecosystem respiration (oxygen consumption in the water column and sediments) around the 1996 spring bloom in South San Francisco Bay, California, USA. Measurements were made at a shallow site (2 m, where mean photic depth was 60% of the water column height) and a deep site (15 m, mean photic depth was only 20% of the water column). We also estimated phytoplankton primary production weekly at both sites to develop estimates of net oxygen flux as the sum of pelagic production (PP), pelagic respiration (PR) and benthic respiration (BR). Over the 14 wk period from February 5 to May 14, PP ranged from 2 to 210, PR from 9 to 289, and BR from 0.1 to 48 mmol O2 m-2 d-1, illustrating large variability of estuarine oxygen fluxes at the weekly time scale. Pelagic production exceeded total respiration at the shallow site, but not at the deep site, demonstrating that the shallow domains are net autotrophic but the deep domains are net heterotrophic, even during the period of the spring bloom. If we take into account the potential primary production by benthic microalgae, the estuary as a whole is net autotrophic during spring, net heterotrophic during the nonbloom seasons, and has a balanced net metabolism over a full annual period. The seasonal shift from net autotrophy to heterotrophy during the transition from spring to summer was accompanied by a large shift from dominance by pelagic respiration to dominance by benthic respiration. This suggests that changes in net ecosystem metabolism can reflect changes in the pathways of energy flow in shallow coastal ecosystems.

Caffrey, J.M.; Cloern, J.E.; Grenz, C.

1998-01-01

203

California coast nearshore processes study. [nearshore currents, sediment transport, estuaries, and river discharge  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Large scale sediment plumes from intermittent streams and rivers form detectable seasonal patterns on ERTS-1 imagery. The ocean current systems, as plotted from three California coast ERTS mosaics, were identified. Offshore patterns of sediment in areas such as the Santa Barbara Channel are traceable. These patterns extend offshore to heretofore unanticipated ranges as shown on the ERTS-1 imagery. Flying spot scanner enhancements of NASA tapes resulted in details of subtle and often invisible (to the eye) nearshore features. The suspended sediments off San Francisco and in Monterey Bay are emphasized in detail. These are areas of extremely changeable offshore sediment transport patterns. Computer generated contouring of radiance levels resulted in maps that can be used in determining surface and nearsurface suspended sediment distribution. Tentative calibrations of ERTS-1 spectral brightness against sediment load have been made using shipboard measurements. Information from the combined enhancement and interpretation techniques is applicable to operational coastal engineering programs.

Pirie, D. M.; Steller, D. D. (principal investigators)

1973-01-01

204

Tides, and tidal and residual currents in Suisun and San Pablo bays, California; results of measurements, 1986  

USGS Publications Warehouse

Current meter data collected at 11 stations and water level data collected at one station in Suisun and San Pablo Bays, California, in 1986 are compiled in this report. Current-meter measurements include current speed and direction, and water temperature and salinity (computed from temperature and conductivity). For each of the 19 current-meter records, data are presented in two forms. These are: (1) results of harmonic analysis; and (2) plots of tidal current speed and direction versus time and plots of temperature and salinity versus time. Spatial distribution of the properties of tidal currents are given in graphic form. In addition, Eulerian residual currents have been compiled by using a vector-averaging technique. Water level data are presented in the form of a time-series plot and the results of harmonic analysis. (USGS)

Gartner, J.W.; Yost, B.T.

1988-01-01

205

Biogeography and phenology of satellite-measured phytoplankton seasonality in the California current  

NASA Astrophysics Data System (ADS)

Thirteen years (1998-2010) of satellite-measured chlorophyll a are used to establish spatial patterns in climatological phytoplankton biomass seasonality across the California Current System (CCS) and its interannual variability. Multivariate clustering based on the shape of the local climatological seasonal cycle divides the study area into four groups: two with spring-summer maxima representing the northern and southern coastal upwelling zones, one with a summer minimum offshore in mid-latitudes and a fourth with very weak seasonality in between. Multivariate clustering on the seasonal cycles from all 13 years produces the same four seasonal cycle types and provides a view of the interannual variability in seasonal biogeography. Over the study period these seasonal cycles generally appear in similar locations as the climatological clusters. However, considerable interannual variability in the geography of the seasonal cycles is evident across the CCS, the most spatially extensive of which are associated with the 1997-1999 El Niño-Southern Oscillation (ENSO) signal and the 2005 delayed spring transition off the Oregon and northern and central California coasts. We quantify linear trends over the study period in the seasonal timing of the two seasonal cycles that represent the biologically productive coastal upwelling zones using four different metrics of phenology. In the northern upwelling region, the date of the spring maximum is delaying (1.34 days yr-1) and the central tendency of the summer elevated chlorophyll period is advancing (0.63 days yr-1). In the southern coastal upwelling region, both the initiation and cessation of the spring maximum are delaying (1.78 days yr-1 and 2.44 days yr-1, respectively) and the peak is increasing in duration over the study period. Connections between observed interannual shifts in phytoplankton seasonality and physical forcing, expressed as either basin-scale climate signals or local forcing, show phytoplankton seasonality in the CCS to be influenced by changes in the seasonality of the wind mixing power offshore, coastal upwelling in the near-shore regions and basin-scale signals such as ENSO across the study area.

Foukal, Nicholas P.; Thomas, Andrew C.

2014-10-01

206

Landscape anthropogenic disturbance in the Mediterranean ecosystem: is the current landscape sustainable?  

NASA Astrophysics Data System (ADS)

Mediterranean landscape during the last centuries has been subject to strong anthropogenic disturbances who shifted natural vegetation cover in a cultural landscape. Most of the natural forest were destroyed in order to allow cultivation and grazing activities. In the last century, fast growing conifer plantations were introduced in order to increase timber production replacing slow growing natural forests. In addition, after the Second World War most of the grazing areas were changed in unmanaged mediterranean conifer forest frequently spread by fires. In the last decades radical socio economic changes lead to a dramatic abandonment of the cultural landscape. One of the most relevant result of these human disturbances, and in particular the replacement of deciduous forests with coniferous forests, has been the increasing in the number of forest fires, mainly human caused. The presence of conifers and shrubs, more prone to fire, triggered a feedback mechanism that makes difficult to return to the stage of potential vegetation causing huge economic, social and environmental damages. The aim of this work is to investigate the sustainability of the current landscape. A future landscape scenario has been simulated considering the natural succession in absence of human intervention assuming the current fire regime will be unaltered. To this end, a new model has been defined, implementing an ecological succession model coupled with a simply Forest Fire Model. The ecological succession model simulates the vegetation dynamics using a rule-based approach discrete in space and time. In this model Plant Functional Types (PFTs) are used to describe the landscape. Wildfires are randomly ignited on the landscape, and their propagation is simulated using a stochastic cellular automata model. The results show that the success of the natural succession toward a potential vegetation cover is prevented by the frequency of fire spreading. The actual landscape is then unsustainable because of the high cost of fire fighting activities. The right path to success consists in development of suitable land use planning and forest management to mitigate the consequences of past anthropogenic disturbances.

Biondi, Guido; D'Andrea, Mirko; Fiorucci, Paolo; Franciosi, Chiara; Lima, Marco

2013-04-01

207

The invasive bullfrog Lithobates catesbeianus in oases of Baja California Sur, Mexico: potential effects in a fragile ecosystem  

Microsoft Academic Search

The American bullfrog (Lithobates catesbeianus), considered as one of the world’s worst invasive species because of its negative effects on native fauna, has been introduced\\u000a into over 40 countries in four continents. The invasion status in Mexico is poorly known. The first known record for this\\u000a species in the Peninsula of Baja California, northwestern Mexico is an individual collected 35 years

Víctor H. Luja; Ricardo Rodríguez-Estrella

2010-01-01

208

Water, Energy, and Ecosystems: A Case Study of California's Sierra Nevada to Assess Vulnerability to Climate Change and Opportunities for Adaptation  

NASA Astrophysics Data System (ADS)

We report here on a major effort to define and quantify metrics of vulnerability to climate change for the west-slope of California’s Sierra Nevada. We have defined the vulnerability of flowing surface waters used for human and ecological purposes as a function of exposure and sensitivity to anticipated hydrologic alteration mediated by regional climate warming and as measured by changes in the flow regime. This effort includes the development, parameterization, and calibration of the WEAP21 water management model to depict climate warming scenarios for fifteen major west-slope basins of the Sierra Nevada at the sub-watershed scale. The outcomes of this modeling effort include dimensions of water delivery, hydropower energy production, recreation, and aquatic ecosystem functioning. For example, our previously reported simulations indicated that, with uniform +6° C warming in surface air temperature, hydrologic alteration would be non-uniformly distributed across basins, with variance driven by latitude and basin hypsography. By incorporating a variable climatic time series, we were able to identify basins with substantial reductions in mean annual discharge, progressive negative shifts in annual hydrographic center of mass, and increased duration of low flow events. We found that basins with the greatest simulated change from baseline conditions were also the most variable across water years, presenting challenges to future water management schemes. Further, when simulated hydrologic alterations were studied for changes to hydropower energy production - assuming that operating rules remain stationary - we determined that, while wetter months generated on average more hydropower, annual discharge losses reduced overall generation capacity with dramatic decreases in dry months that are both hotter and experience greater energy demand. These simulated alterations to baseline hydrology with warming scenarios also indicated cascading impacts on other beneficial uses of water, such as substantial reductions in whitewater kayaking opportunities in unregulated rivers during summer months. With respect to ecohydrological conditions in the Sierra Nevada, stream water temperatures are perhaps the most important, as this water quality parameter not only helps govern ecosystem productivity, but can also represent sub-lethal and lethal conditions when biotic thresholds are surpassed. To better understand vulnerability of ecosystems, we contrast unimpaired and regulated simulations of hydrology and concomitant water temperatures to isolate the effects of ecosystem management, and evaluate departures from baseline conditions. The net result of modeled simulations, when viewed in the context of vulnerability, is a number of thematic metrics that can be evaluated within a spatiotemporal framework to assess opportunities for science-based adaptive resource management. We explore these opportunities for institutional adaptation by reviewing policy options that address inefficiencies and conflicts in water management with a specific focus on the relicensing of dams, environmental flow requirements, and management of the water, energy, and ecosystem nexus.

Viers, J. H.; Null, S.; Ligare, S. T.; Rheinheimer, D. E.; Williams, J. N.

2010-12-01

209

Current status and historical trends of organochlorine pesticides in the ecosystem of Deep Bay, South China  

NASA Astrophysics Data System (ADS)

To characterize the current status and historical trends in organochlorine pesticides (OCPs) contamination in Deep Bay, an important water body between Hong Kong and mainland China with a Ramsar mangrove wetland (Maipo), samples from seawater, suspended particulate matter (SPM), surface sediment, sediment core and fish were collected to determine the OCPs concentrations. Sediment core dating was accomplished using the 210Pb method. The average concentrations of DDTs, HCHs and chlordanes in water were 1.96, 0.71, 0.81 ng l -1, while in SPM were 36.5, 2.5, 35.7 ng g -1 dry weight, in surface sediment were 20.2, 0.50, 2.4 ng g -1 dry weight, and in fish were 125.4, 0.43, 13.1 ng g -1 wet weight, respectively. DDTs concentrations in various matrices of Deep Bay were intermediate compared with those in other areas. Temporal trends of the targeted OCPs levels in sediment core generally increased from 1948 to 2004, with the highest levels in top or sub-surface sediment. Both DDT composition and historical trends indicated an ongoing fresh DDT input. A positive relationship between the bioconcentration factor (BCF) of target chemicals and the corresponding octanol-water partition coefficient ( Kow), and between the biota-sediment accumulation factors (BSAF) and the Kow were observed in the Bay. The risk assessment indicated that there were potential ecological and human health risks for the target OCPs in Deep Bay.

Qiu, Yao-Wen; Zhang, Gan; Guo, Ling-Li; Cheng, Hai-Rong; Wang, Wen-Xiong; Li, Xiang-Dong; Wai, Onyx W. H.

2009-11-01

210

Methane budget of the down-current plume from Coal Oil Point seep field, Santa Barbara Channel, California  

Microsoft Academic Search

Previous research indicates that 5.5-9.6 x 106 mol\\/d (90-150 t\\/d) of methane are emitted from the seafloor into the coastal ocean near Coal Oil Point (COP), Santa Barbara Channel (SBC), California. Methane concentrations and biologically-mediated oxidation rates were quantified at 12 stations in a 198 km2 area down-current from COP during the SEEPS\\

S. Mau; M. Heintz; D. L. Valentine

2008-01-01

211

Bio-Optical Measurement and Modeling of the California Current and Polar Oceans. Chapter 13  

NASA Technical Reports Server (NTRS)

This Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) project contract supports in situ ocean optical observations in the California Current, Southern Ocean, Indian Ocean as well as merger of other in situ data sets we have collected on various global cruises supported by separate grants or contracts. The principal goals of our research are to validate standard or experimental products through detailed bio-optical and biogeochemical measurements, and to combine ocean optical observations with advanced radiative transfer modeling to contribute to satellite vicarious radiometric calibration and advanced algorithm development. In collaboration with major oceanographic ship-based observation programs funded by various agencies (CalCOFI, US JGOFS, NOAA AMLR, INDOEX and Japan/East Sea) our SIMBIOS effort has resulted in data from diverse bio-optical provinces. For these global deployments we generate a high-quality, methodologically consistent, data set encompassing a wide-range of oceanic conditions. Global data collected in recent years have been integrated with our on-going CalCOFI database and have been used to evaluate Sea-Viewing Wide Field-of-view Sensor (SeaWiFS) algorithms and to carry out validation studies. The combined database we have assembled now comprises more than 700 stations and includes observations for the clearest oligotrophic waters, highly eutrophic blooms, red-tides and coastal case two conditions. The data has been used to validate water-leaving radiance estimated with SeaWiFS as well as bio optical algorithms for chlorophyll pigments. The comprehensive data is utilized for development of experimental algorithms (e.g., high-low latitude pigment transition, phytoplankton absorption, and cDOM).

Mitchell, B. Greg

2001-01-01

212

Bio-Optical Measurement and Modeling of the California Current and Polar Oceans  

NASA Technical Reports Server (NTRS)

The principal goals of our research are to validate standard or experimental products through detailed bio-optical and biogeochemical measurements, and to combine ocean optical observations with advanced radiative transfer modeling to contribute to satellite vicarious radiometric calibration and advanced algorithm development. To achieve our goals requires continued efforts to execute complex field programs globally, as well as development of advanced ocean optical measurement protocols. We completed a comprehensive set of ocean optical observations in the California Current, Southern Ocean, Indian Ocean requiring a large commitment to instrument calibration, measurement protocols, data processing and data merger. We augmented separately funded projects of our own, as well as others, to acquire ill situ data sets we have collected on various global cruises supported by separate grants or contracts. In collaboration with major oceanographic ship-based observation programs funded by various agencies (CalCOFI, US JGOFS, NOAA AMLR, INDOEX and Japan/East Sea) our SIMBIOS effort has resulted in data from diverse bio-optical provinces. For these global deployments we generate a high-quality, methodologically consistent, data set encompassing a wide-range of oceanic conditions. Global data collected in recent years have been integrated with our on-going CalCOFI database and have been used to evaluate SeaWiFS algorithms and to carry out validation studies. The combined database we have assembled now comprises more than 700 stations and includes observations for the clearest oligotrophic waters, highly eutrophic blooms, red-tides and coastal case 2 conditions. The data has been used to validate water-leaving radiance estimated with SeaWiFS as well as bio-optical algorithms for chlorophyll pigments. The comprehensive data is utilized for development of experimental algorithms (e.g. high-low latitude pigment transition, phytoplankton absorption, and cDOM). During this period we completed 9 peer-reviewed publications in high quality journals, and presented aspects of our work at more than 10 scientific conferences.

Mitchell, B. Greg; Fargion, Giulietta S. (Technical Monitor)

2001-01-01

213

Thermohaline structure in the California Current System: Observations and modeling of spice variance  

NASA Astrophysics Data System (ADS)

Upper ocean thermohaline structure in the California Current System is investigated using sustained observations from autonomous underwater gliders and a numerical state estimate. Both observations and the state estimate show layers distinguished by the temperature and salinity variability along isopycnals (i.e., spice variance). Mesoscale and submesoscale spice variance is largest in the remnant mixed layer, decreases to a minimum below the pycnocline near 26.3 kg m-3, and then increases again near 26.6 kg m-3. Layers of high (low) meso- and submesoscale spice variance are found on isopycnals where large-scale spice gradients are large (small), consistent with stirring of large-scale gradients to produce smaller scale thermohaline structure. Passive tracer adjoint calculations in the state estimate are used to investigate possible mechanisms for the formation of the layers of spice variance. Layers of high spice variance are found to have distinct origins and to be associated with named water masses; high spice variance water in the remnant mixed layer has northerly origin and is identified as Pacific Subarctic water, while the water in the deeper high spice variance layer has southerly origin and is identified as Equatorial Pacific water. The layer of low spice variance near 26.3 kg m-3 lies between the named water masses and does not have a clear origin. Both effective horizontal diffusivity, ?h, and effective diapycnal diffusivity, ?v, are elevated relative to the diffusion coefficients set in the numerical simulation, but changes in ?h and ?v with depth are not sufficient to explain the observed layering of thermohaline structure.

Todd, Robert E.; Rudnick, Daniel L.; Mazloff, Matthew R.; Cornuelle, Bruce D.; Davis, Russ E.

2012-02-01

214

Conserving the evolutionary potential of California valley oak (Quercus lobata Née): a multivariate genetic approach to conservation planning  

Microsoft Academic Search

California valley oak (Quercus lobata Née) is a seriously threatened endemic oak species in California and a keystone species for foothill oak ecosystems. Urban and agricultural development affects a significant fraction of the species' range and predicted climate change is likely to dislocate many current populations. Here, we explore spatial patterns of multivariate genotypes and genetic diversity throughout the range

DELPHINE GRIVET; VICTORIA L. SORK; ROBERT D. WESTFALL; F R A N K W. D AV

2007-01-01

215

Influence of a multiyear event of low salinity on the zooplankton from Mexican eco-regions of the California Current  

NASA Astrophysics Data System (ADS)

Data are presented from the southern part of the California Current System (CCS) for the period 1997-2007, derived from the IMECOCAL monitoring program. Apart from El Niño 1997 to 1998, and La Niña 1998-1999 the strongest perturbation occurred in 2002 due to an intrusion of subarctic water affecting all the CCS. The response of zooplankton biomass to the strong cooling and freshening of the upper layer was an immediate drop followed by a progressive recovery between 2003 and 2007. Though the low salinity influence ended in 2006, the increased zooplankton trend continued, reinforced by increased upwelling activity beginning 2005 off north Baja California region (30-32°N) and beginning 2006 off central Baja California (24-30°N). Multiple regression analysis was done between regional variables and Upwelling Index (UI) and two basin-scale proxies: the North Pacific Gyre Oscillation (NPGO), and Pacific Decadal Oscillation (PDO). The significant influence of the NPGO on surface salinity, salinity stratification, zooplankton volume and secondary consumers (zooplankton carnivores) suggests a basin scale control on these variables more than local mechanisms. The signature of the NPGO was also evident in the base of the trophic web, but more related to the group of crustacean herbivores in the north eco-region, and the tunicates in central Baja California. In this last region, the effect from NPGO on the zooplankton volume and tunicates was antagonist with UI indicative of similar importance of basin and local processes. However, when the time interval is limited to the post-subarctic intrusion (2003-2007) the significance of multiple regression models and physical variables was lost. Therefore, though data and bio-physical coupling analysis off Baja California suggest a better relation with NPGO compared to PDO, it is still not sufficient to explain the magnitude of the perturbation observed in 2002.

Lavaniegos, Bertha E.

2009-12-01

216

Metagenomic analysis of microbial consortium from natural crude oil that seeps into the marine ecosystem offshore Southern California  

PubMed Central

Crude oils can be major contaminants of the marine ecosystem and microorganisms play a significant role in the degradation of its main constituents. To increase our understanding of the microbial hydrocarbon degradation process in the marine ecosystem, we collected crude oil from an active seep area located in the Santa Barbara Channel (SBC) and generated a total of about 52 Gb of raw metagenomic sequence data. The assembled data comprised ~500 Mb, representing ~1.1 million genes derived primarily from chemolithoautotrophic bacteria. Members of Oceanospirillales, a bacterial order belonging to the Deltaproteobacteria, recruited less than 2% of the assembled genes within the SBC metagenome. In contrast, the microbial community associated with the oil plume that developed in the aftermath of the Deepwater Horizon (DWH) blowout in 2010, was dominated by Oceanospirillales, which comprised more than 60% of the metagenomic data generated from the DWH oil plume. This suggests that Oceanospirillales might play a less significant role in the microbially mediated hydrocarbon conversion within the SBC seep oil compared to the DWH plume oil. We hypothesize that this difference results from the SBC oil seep being mostly anaerobic, while the DWH oil plume is aerobic. Within the Archaea, the phylum Euryarchaeota, recruited more than 95% of the assembled archaeal sequences from the SBC oil seep metagenome, with more than 50% of the sequences assigned to members of the orders Methanomicrobiales and Methanosarcinales. These orders contain organisms capable of anaerobic methanogenesis and methane oxidation (AOM) and we hypothesize that these orders – and their metabolic capabilities – may be fundamental to the ecology of the SBC oil seep. PMID:25197496

Hawley, Erik R.; Piao, Hailan; Scott, Nicole M.; Malfatti, Stephanie; Pagani, Ioanna; Huntemann, Marcel; Chen, Amy; Glavina del Rio, Tijana; Foster, Brian; Copeland, Alex; Jansson, Janet; Pati, Amrita; Tringe, Susannah; Gilbert, Jack A.; Lorenson, Thomas D.; Hess, Matthias

2014-01-01

217

Metagenomic analysis of microbial consortium from natural crude oil that seeps into the marine ecosystem offshore Southern California  

SciTech Connect

Crude oils can be major contaminants of the marine ecosystem and microorganisms play a significant role in the degradation of the main constituents of crude oil. To increase our understanding of the microbial hydrocarbon degradation process in the marine ecosystem, we collected crude oil from an active seep area located in the Santa Barbara Channel (SBC) and generated a total of about 52 Gb of raw metagenomic sequence data. The assembled data comprised ~500 Mb, representing ~1.1 million genes derived primarily from chemolithoautotrophic bacteria. Members of Oceanospirillales, a bacterial order belonging to the Deltaproteobacteria, recruited less than 2% of the assembled genes within the SBC metagenome. In contrast, the microbial community associated with the oil plume that developed in the aftermath of the Deepwater Horizon (DWH) blowout in 2010, was dominated by Oceanospirillales, which comprised more than 60% of the metagenomic data generated from the DWH oil plume. This suggests that Oceanospirillales might play a less significant role in the microbially mediated hydrocarbon conversion within the SBC seep oil compared to the DWH plume oil. We hypothesize that this difference results from the SBC oil seep being mostly anaerobic, while the DWH oil plume is aerobic. Within the Archaea, the phylum Euryarchaeota, recruited more than 95% of the assembled archaeal sequences from the SBC oil seep metagenome, with more than 50% of the sequences assigned to members of the orders Methanomicrobiales and Methanosarcinales. These orders contain organisms capable of anaerobic methanogenesis and methane oxidation (AOM) and we hypothesize that these orders and their metabolic capabilities may be fundamental to the ecology of the SBC oil seep.

Hawley, Erik R.; Piao, Hailan; Scott, Nicole M.; Malfatti, Stephanie; Pagani, Ioanna; Huntemann, Marcel; Chen, Amy; del Rio, Tijana G.; Foster, Brian; Copeland, A.; Jansson, Janet K.; Pati, Amrita; Gilbert, Jack A.; Tringe, Susannah G.; Lorenson, Thomas D.; Hess, Matthias

2014-08-31

218

Springtime distributions of migratory marine birds in the southern California Current: Oceanic eddy associations and coastal habitat hotspots over 17 years  

Microsoft Academic Search

We used a 17-year time series of shipboard observations to address the hypothesis that marine birds associate with persistent hydrographic features in the southern California Current System (CCS). Overall, approximately 27,000km of ocean habitat were surveyed, averaging 1600km per cruise. We identified mesoscale features (eddy centers and the core of the California Current), based on dynamic height anomalies, and considered

P. P. W. Yen; W. J. Sydeman; S. J. Bograd; K. D. Hyrenbach

2006-01-01

219

Measurements of slope currents and internal tides on the Continental Shelf and slope off Newport Beach, California  

USGS Publications Warehouse

An array of seven moorings housing current meters and oceanographic sensors was deployed for 6 months at 5 sites on the Continental Shelf and slope off Newport Beach, California, from July 2011 to January 2012. Full water-column profiles of currents were acquired at all five sites, and a profile of water-column temperature was also acquired at two of the five sites for the duration of the deployment. In conjunction with this deployment, the Orange County Sanitation District deployed four bottom platforms with current meters on the San Pedro Shelf, and these meters provided water-column profiles of currents. The data from this program will provide the basis for an investigation of the interaction between the deep water flow over the slope and the internal tide on the Continental Shelf.

Rosenberger, Kurt; Noble, Marlene A.; Norris, Benjamin K.

2014-01-01

220

Measurements of nitrite production in and around the primary nitrite maximum in the central California Current  

NASA Astrophysics Data System (ADS)

Nitrite (NO2-) is a substrate for both oxidative and reductive microbial metabolism. NO2- accumulates at the base of the euphotic zone in oxygenated, stratified open-ocean water columns, forming a feature known as the primary nitrite maximum (PNM). Potential pathways of NO2- production include the oxidation of ammonia (NH3) by ammonia-oxidizing bacteria and archaea as well as assimilatory nitrate (NO3-) reduction by phytoplankton and heterotrophic bacteria. Measurements of NH3 oxidation and NO3- reduction to NO2- were conducted at two stations in the central California Current in the eastern North Pacific to determine the relative contributions of these processes to NO2- production in the PNM. Sensitive (< 10 nmol L-1), precise measurements of [NH4+] and [NO2-] indicated a persistent NH4+ maximum overlying the PNM at every station, with concentrations as high as 1.5 ?mol L-1. Within and just below the PNM, NH3 oxidation was the dominant NO2- producing process, with rates of NH3 oxidation to NO2- of up to 31 nmol L-1 d-1, coinciding with high abundances of ammonia-oxidizing archaea. Though little NO2- production from NO3- was detected, potentially nitrate-reducing phytoplankton (photosynthetic picoeukaryotes, Synechococcus, and Prochlorococcus) were present at the depth of the PNM. Rates of NO2- production from NO3- were highest within the upper mixed layer (4.6 nmol L-1 d-1) but were either below detection limits or 10 times lower than NH3 oxidation rates around the PNM. One-dimensional modeling of water column NO2- production agreed with production determined from 15N bottle incubations within the PNM, but a modeled net biological sink for NO2- just below the PNM was not captured in the incubations. Residence time estimates of NO2- within the PNM ranged from 18 to 470 days at the mesotrophic station and was 40 days at the oligotrophic station. Our results suggest the PNM is a dynamic, rather than relict, feature with a source term dominated by ammonia oxidation.

Santoro, A. E.; Sakamoto, C. M.; Smith, J. M.; Plant, J. N.; Gehman, A. L.; Worden, A. Z.; Johnson, K. S.; Francis, C. A.; Casciotti, K. L.

2013-11-01

221

Current Status and Future Prospects for the Assessment of Marine and Coastal Ecosystem Services: A Systematic Review  

PubMed Central

Background Research on ecosystem services has grown exponentially during the last decade. Most of the studies have focused on assessing and mapping terrestrial ecosystem services highlighting a knowledge gap on marine and coastal ecosystem services (MCES) and an urgent need to assess them. Methodology/Principal Findings We reviewed and summarized existing scientific literature related to MCES with the aim of extracting and classifying indicators used to assess and map them. We found 145 papers that specifically assessed marine and coastal ecosystem services from which we extracted 476 indicators. Food provision, in particular fisheries, was the most extensively analyzed MCES while water purification and coastal protection were the most frequently studied regulating and maintenance services. Also recreation and tourism under the cultural services was relatively well assessed. We highlight knowledge gaps regarding the availability of indicators that measure the capacity, flow or benefit derived from each ecosystem service. The majority of the case studies was found in mangroves and coastal wetlands and was mainly concentrated in Europe and North America. Our systematic review highlighted the need of an improved ecosystem service classification for marine and coastal systems, which is herein proposed with definitions and links to previous classifications. Conclusions/Significance This review summarizes the state of available information related to ecosystem services associated with marine and coastal ecosystems. The cataloging of MCES indicators and the integrated classification of MCES provided in this paper establish a background that can facilitate the planning and integration of future assessments. The final goal is to establish a consistent structure and populate it with information able to support the implementation of biodiversity conservation policies. PMID:23844080

Liquete, Camino; Piroddi, Chiara; Drakou, Evangelia G.; Gurney, Leigh; Katsanevakis, Stelios; Charef, Aymen; Egoh, Benis

2013-01-01

222

Annual prey consumption of a dominant seabird, Common Murre, in the California Current  

Microsoft Academic Search

We collated information on population size, diet composition, energy requirements, energy densities of prey species, and assimilation efficiency from the literature to estimate annual prey consumption by Common Murres (Uria aalge) between Cape Blanco, Oregon and Point Conception, California in 2004. We estimated that the population consumed approximately 242,250 metric tons of prey, including 70,500 metric tons consumed by breeding

Jennifer E. Roth; Nadav Nur; Pete Warzybok; William J. Sydeman

223

The Extent and Recurrence of Holocene Turbidity Currents in Monterey Canyon and Fan Channel, offshore California  

Microsoft Academic Search

The Monterey Canyon and fan channel system is a large and active conduit for sediment transport on the central California margin. The proximity of the canyon head to the shoreline, coupled with longshore sand transport in Monterey Bay, allows frequent (several\\/year) sediment gravity flows to enter the canyon and deposit coarse gravel and sand down the canyon axis. ROV-guided observations

J. E. Johnson; C. K. Paull; W. Normark; W. Ussler

2006-01-01

224

Comparison of the seasonal and interannual variability of phytoplankton pigment concentrations in the Peru and California Current systems  

NASA Technical Reports Server (NTRS)

Monthly composite images from the global coastal zone color scanner (CZCS) data set are used to provide an initial illustration and comparison of seasonal and interannual variability of phytoplankton pigment concentration along the western coasts of South and North America in the Peru Current system (PCS) and California Current system (CCS). The analysis utilizes the entire time series of available data (November 1978 to June 1986) to form a mean annual cycle and an index of interannual variability for a series of both latitudinal and cross-shelf regions within each current system. Within 100 km of the coast, the strongest seasonal cycles in the CCS are in two regions, one between 34 deg and 45 deg N and the second between 24 deg and 29 deg N, each with maximum concentrations (greater than 3.0 mg m(exp-3)) in May-June. Weaker seasonal variability is present north of 45 deg N and in the Southern California Bight region (32 deg N). Within the PCS, in the same 100-km-wide coastal region, highest (greater than 45 deg S) and lowest (less than 20 deg S) latitude regions have a similar seasonal cycle with maximum concentrations (greater than 1.5 mg m(exp -3)) during the austral spring, summer, and fall, matching that evident throughout the CCS. Between these regions, off northern and central Chile, the seasonal maximum occurs during July-August (austral winter), contrary to the influence of upwelling favorable winds. Within the CCS, the dominant feature of interannual variability in the 8-year time series is a strong negative concentration anomaly in 1983, an El Nino year. The relative value of this negative anomaly is strongest off central California and is followed by an even stronger negative anomaly is strongest off central California and is followed by an even stronger negative anomaly in 1984 off Baja, California. In the PCS, strong negative anomalies during the 1982-1983 El Nino period are evident only off the Peruvian coast and are evident there only in the regions 100 km or more from the coast. Although negative anomalies associated with the El Nino were not present at higher latitudes (more than approximately 20 deg S) in the PCS, the extremely sparse sampling weakens our confidence in the results of the interannual analysis in this region. An upper estimate of the systematic winter bias remaining in the global CZCS data after reprocessing with the multiple scattering algorithm is given in the appendix.

Thomas, A. C.; Huang, F.; Strub, P. T.; James, C.

1994-01-01

225

Air-sea exchange of CO2 at a Northern California coastal site along the California Current upwelling system  

NASA Astrophysics Data System (ADS)

It is not well understood whether coastal upwelling is a net CO2 source to the atmosphere or a net CO2 sink to the ocean due to high temporal variability of air-sea CO2 exchange (CO2 flux) in coastal upwelling zones. Upwelling transports heterotrophic, CO2 enriched water to the surface and releases CO2 to the atmosphere, whereas the presence of nutrient-rich water at the surface supports high primary production and atmospheric CO2 uptake. To quantify the effects of upwelling on CO2 flux, we measured CO2 flux at a coastal upwelling site off of Bodega Bay, California, with the eddy covariance technique during the summer of 2007 and the fall of 2008, and the bulk method with partial pressure of CO2 of surface water (pCO2) data from November 2010 to July 2011. Variations in sea surface temperatures (SST) and alongshore wind velocity suggest that the measurement period in 2007 coincided with a typical early summer upwelling period and the measurement period in 2008 was during a typical fall relaxation period. A strong source of CO2 (~ 1.5 ± 7 SD (standard deviation) g C m-2 day-1) from the ocean to the atmosphere during the upwelling period was concurrent with high salinity, low SST, and low chlorophyll density. In contrast, a weak source of CO2 flux (~ 0.2 ± 3 SD g C m-2 day-1) was observed with low salinity, high SST and high chlorophyll density during the relaxation period. Similarly, the sink and source balance of CO2 flux was highly related to salinity and SST during the pCO2 measurement periods; high salinity and low SST corresponded to high pCO2, and vice versa. We estimated that the coastal area off Bodega Bay was likely an overall source of CO2 to the atmosphere based on the following conclusions: (1) the overall CO2 flux estimated from both eddy covariance and pCO2 measurements showed a source of CO2; (2) although the relaxation period during the 2008 measurements were favorable to CO2 uptake, CO2 flux during this period was still a slight source; (3) salinity and SST were found to be good predictors of the CO2 flux for both eddy covariance and pCO2 measurements, and 99% of the historical SST and salinity data available between 1988 and 2011 fell within the range of our observations in May-June 2007, August-September 2008 and November 2010-July~2011, which indicates that our data set was representative of the annual variations in the sea state. Based on the developed relationship between pCO2, SST and salinity, the study area between 1988 and 2011 was estimated to be an annual source of CO2 of ~ 35 mol C m-2 yr-1. The peak monthly CO2 flux of ~ 7 mol C m-2 month-1 accounted for almost 30% of the dissolved inorganic carbon in the surface mixed layer.

Ikawa, H.; Faloona, I.; Kochendorfer, J.; Paw U, K. T.; Oechel, W. C.

2013-07-01

226

Direct-Current Resistivity Profiling at the Pecos River Ecosystem Project Study Site near Mentone, Texas, 2006  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with Texas A&M University AgriLife, did a surface geophysical investigation at the Pecos River Ecosystem Project study site near Mentone in West Texas intended to determine shallow (to about 14 meters below the water [river] surface) subsurface composition (lithology) in and near treated (eradicated of all saltcedar) and control (untreated) riparian zone sites during June-August 2006. Land-based direct-current resistivity profiling was applied in a 240-meter section of the riverbank at the control site, and waterborne direct-current continuous resistivity profiling (CRP) was applied along a 2.279-kilometer reach of the river adjacent to both sites to collect shallow subsurface resistivity data. Inverse modeling was used to obtain a nonunique estimate of the true subsurface resistivity from apparent resistivity calculated from the field measurements. The land-based survey showed that the sub-surface at the control site generally is of relatively low resis-tivity down to about 4 meters below the water surface. Most of the section from about 4 to 10 meters below the water surface is of relatively high resistivity. The waterborne CRP surveys convey essentially the same electrical representation of the lithology at the control site to 10 meters below the water surface; but the CRP surveys show considerably lower resistivity than the land-based survey in the subsection from about 4 to 10 meters below the water surface. The CRP surveys along the 2.279-kilometer reach of the river adjacent to both the treated and control sites show the same relatively low resistivity zone from the riverbed to about 4 meters below the water surface evident at the control site. A slightly higher resistivity zone is observed from about 4 to 14 meters below the water surface along the upstream approximately one-half of the profile than along the downstream one-half. The variations in resistivity could not be matched to variations in lithology because sufficient rock samples were not available.

Teeple, Andrew P.; McDonald, Alyson K.; Payne, Jason D.; Kress, Wade H.

2009-01-01

227

Preliminary evaluation of the performance, water use, and current application trends of evaporative coolers in California climates  

SciTech Connect

This paper describes the latest results of an ongoing analysis investigating the potential for evaporative cooling as an energy-efficient alternative to standard air-conditioning in California residences. In particular, the study uses detailed numerical models of evaporative coolers linked with the DOE-2 building energy simulation program to study the issues of indoor comfort, energy and peak demand savings with and without supplemental air-conditioning and consumptive water use. In addition, limited surveys are used to assess the current market availability of evaporative cooling in California, typical contractor practices and costs, and general acceptance of the technology among engineers, contractors, and manufacturers. The results show that evaporative coolers can provide significant energy and peak demand savings in California residences, but the impact of the increased indoor humidity on human comfort remains an unanswered question that requires further research and clarification. Evaluated against ASHRAE comfort standards developed primarily for air-conditioning both direct and two-stage evaporative coolers would not maintain comfort at peak cooling conditions due to excessive humidity. However, using bioclimatic charts that place human comfort at the 80% relative humidity line, the study suggests that direct evaporative coolers will work in mild coastal climates, while two-stage models should provide adequate comfort in Title 24 houses throughout California, except in the Imperial Valley. The study also shows that evaporative coolers will increase household water consumption by less than 6% on an annual basis, and as much as 23% during peak cooling months, and that the increases in water cost are minimal compared to the electricity savings. Lastly, a survey of engineers and contractors revealed generally positive experiences with evaporative coolers, with operational cost savings, improved comfort, unproved air quality as the primary benefits in their use.

Huang, Y.J.; Hanford, J.W.; Wu, H.F.

1992-09-01

228

Recovery strategies for the California clapper rail (Rallus longirostris obsoletus) in the heavily-urbanized San Francisco estuarine ecosystem  

USGS Publications Warehouse

The California clapper rail (Rallus longirostris obsoletus), a Federal- and State-listed endangered marsh bird, has a geographic range restricted to one of the most heavily-urbanized estuaries in the world. The rail population has long been in a state of decline, although the exact contribution of each of the many contributing causes remains unclear. The rail is one of the key targets of emerging plans to conserve and restore tidal marshlands. Reduction of tidal marsh habitat, estimated at 85-95%, has been the major historical cause of rail decline. Increased predation intensity may be the more important present problem, because habitat fragmentation and alteration coupled with the invasion of the red fox have made the remaining populations more vulnerable to predators. Population viability analysis shows that adult survivorship is the key demographic variable; reversals in population fate occur over a narrow range of ecologically realistic values. Analysis of habitat requirements and population dynamics of the clapper rail in the San Francisco Estuary shows that decreased within-marsh habitat quality, particularly reduction of tidal flows and alteration of drainage, is an important barrier to population recovery. Management and restoration activities should emphasize the development of well-channelized high tidal marsh, because this is the key requirement of rail habitat. Developing effective restoration programs depends upon having information that field research will not provide. The effect of spatial pattern of reserves requires accurate estimation of the effects of predation and inter-marsh movement, both of which are practically impossible to measure adequately. It will be necessary to develop and use simulation models that can be applied to geographic data to accomplish this task.

Foin, T.C.; Garcia, E.J.; Gill, R.E.; Culberson, S.D.; Collins, J.N.

1997-01-01

229

Climatic Warming and the Decline of Zooplankton in the California Current  

Microsoft Academic Search

Since 1951, the biomass of macrozooplankton in waters off southern California has decreased by 80 percent. During the same period, the surface layer warmed-by more than 1.5^circC in some places-and the temperature difference across the thermocline increased. Increased stratification resulted in less lifting of the thermocline by wind-driven upwelling. A shallower source of upwelled waters provided less inorganic nutrient for

Dean Roemmich; John McGowan

1995-01-01

230

Climate warming and the decline of zooplankton in the California current  

Microsoft Academic Search

Since 1951, the biomass of macrozooplankton in waters off southern California has decreased by 80 percent. During the same period, the surface layer warmed-by more than 1.5°C in some places-and the temperature differences across the thermocline increased. Increased stratification resulted in less lifting of the thermocline by wind-driven upwelling. A shallower source of upwelled waters provided less inorganic nutrient for

D. Roemmich; J. McGowan

1995-01-01

231

Subtidal currents over the central California slope: Evidence for offshore veering of the undercurrent and for direct, wind-driven slope currents  

USGS Publications Warehouse

In February 1991, an array of six current-meter moorings was deployed for one year across the central California outer shelf and slope. The main line of the array extended 30 km offshore of the shelf break, out to water depths of 1400 m. A more sparsely-instrumented line, displaced 30 km to the northwest, extended 14 km offshore. Though shorter, the northern line spanned similar water depths because the gradient of the topography steepened in the northern region. A poleward flow pattern, typical of the California undercurrent, was seen across both lines in the array over most of the year. The poleward flow was surface intensified. In general, the portion of the undercurrent that crossed the southern line had larger amplitudes and penetrated more deeply into the water column than the portion that crossed the northern line. Transport over the year ranged from 0 to 2.5 Sverdrups (Sv) poleward across the southern line; 0 to 1 Sv poleward across the northern line. We suggest the difference in transport was caused by topographic constraints, which tended to force the poleward flow offshore of the northern measurement sites. The slope of the topography steepened too abruptly to allow the poleward flow to follow isobaths when currents were strong. When current velocities lessened, a more coherent flow pattern was seen across both lines in the array. In general, the poleward flow patterns in the undercurrent were not affected by local winds or by the local alongshore pressure gradient. Nor was a strong seasonal pattern evident. Rather unexpectedly, a small but statistically significant fraction of the current variance over the mid- and outer slope was driven by the surface wind stress. An alongshelf wind stress caused currents to flow along the slope, parallel to the wind field, down to depths of 400 m below the surface and out to distances of 2 Rossby radii past the shelf break. The transfer functions were weak, 3-4 cm/s per dyn cm-2, but comparable to wind-driven current amplitudes of 4-6 cm/s per unit wind stress over the middle shelf. Equatorward, alongshelf winds also caused water from 200-300 m over the slope to upwell onto the shelf as the surface water moved offshore.

Noble, M.A.; Ramp, S.R.

2000-01-01

232

Decadal Changes in Ozone and Emissions in Central California and Current Issues  

NASA Astrophysics Data System (ADS)

The relationships among ozone, emissions, and meteorology are very complex in central California, and must be well studied and understood in order to facilitate better air quality planning. Factors significantly impacting changes in emissions such as economic and population growth, and adopted emission controls make the matter even more complex. Here we review the history of ozone pollution in central California since the 1970s to plan for the future. Since the 1970s, changes in emissions have been accompanied by likewise dramatic changes in region-to-region differences in air quality. We focus on the coastal San Francisco Bay Area (SFBA) and the inland San Joaquin Valley (SJV). In the 1970s, the SFBA population was approaching 5 million people while the considerably larger and more rural SJV population remained below 2 million. The SFBA population was mostly confined to coastal locations. Peak ozone levels occurred mostly around the population centers and especially over the Bay itself. Hourly average ozone levels routinely approached 160 ppb. These high ozone levels promoted regulations under which SFBA emissions were continuously reduced through the present. By the 1990s, SFBA emissions had been reduced considerably despite the region's population growing to around 6 million. Relative to the 1970s, in 1990s the SFBA had lower peak ozone levels that were shifted to inland locations where much of the population growth was occurring. The SFBA still exceeded the federal 1-hour standard. A rapidly changing economic landscape in the 1970s promoted vast changes in the central California population distribution. In the SJV, the OPEC oil crisis promoted significant development of petroleum resources. Meanwhile, family farms were quickly being replaced with commercial-scale farming operations. The SJV population rapidly expanded to around 3 million people by the early 1990s. During this time, SJV emissions increased considerably, largely from increases in mobile source activities. The previously sparsely populated SJV had quickly developed an even more severe ozone problem than previous years. From 1990 to 2010, the SFBA population expanded to inland locations and then even further into the sheltered SJV. SFBA emissions for ROG and NOx were decreased around 40% and 15%, respectively during this period. High ozone levels became rather infrequent for coastal SFBA locations. During the same period, the SJV population continued to expand rapidly while emissions decreased, especially for ROG. Peak ozone levels remained around 100 ppb and shifted to locations downwind of Fresno and Bakersfield. Central California has experienced perhaps the most dramatic population growth and shifts in the United States during the contemporary economic era. These changes in population have led to some of the most difficult air quality management problems faced by regulators in the United States. Lessons learned from central California highlight the potential benefits of acting early and also the necessity for a long-term, flexible approach using sustained regulations to accompany population changes.

Tanrikulu, S.; Beaver, S.; Soong, S.; Tran, C.; Cordova, J.; Palazoglu, A.

2011-12-01

233

Observed and Modeled Currents from the Tohoku-oki, Japan and other Recent Tsunamis in Northern California  

NASA Astrophysics Data System (ADS)

We investigate the currents produced by recent tsunamis in Humboldt Bay and Crescent City, California. The region is susceptible to both near-field and far-field tsunamis and has a historic record of damaging events. Crescent City Harbor, located approximately 100 kms north of Humboldt Bay, suffered US 28 million in damages from strong currents produced by the 2006 Kuril Islands tsunami and an additional US 26 million from the 2011 Japan tsunami. In order to better evaluate these currents in northern California, we deployed a Nortek Aquadopp 600 kHz 2D acoustic Doppler current profiler (ADCP) with a 1-min sampling interval in Humboldt Bay, near the existing National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) tide gauge station. The instrument recorded the tsunamis produced by the Mw 8.8 Chile earthquake on February 27, 2010 and the Mw 9.0 Japan earthquake on March 11, 2011. One other tsunami was recorded on the Humboldt Bay tide gauge during the period of ADCP operation, but was not visible on the ADCP, suggesting a threshold water level value of about 0.2 m to produce an observable ADCP record. The 2010 tsunami currents persisted in Humboldt Bay for approximately 30 h with peak amplitudes of about 0.35 m/s. The 2011 tsunami signal lasted for over 40 h with peak amplitude of 0.84 m/s. The strongest currents corresponded to the maximum change in water level approximately 67 min after the initial wave arrival. No damage was observed in Humboldt Bay for either event. In Crescent City, currents for the first three and one-half hours of the 2011 Japan tsunami were estimated using security camera video footage from the Harbor Master, approximately 70 m away from the NOAA-NOS tide gauge station. The largest amplitude tide gauge water-level oscillations and most of the damage occurred within this time window. The currents reached a velocity of approximately 4.5 m/s and six cycles exceeded 3 m/s during this period. Measured current velocities both in Humboldt Bay and in Crescent City were compared to calculated velocities from the Method of Splitting Tsunamis (MOST) numerical model. The frequency and pattern of current amplification and decay at both locations are replicated by the MOST model for the first several hours after the tsunami onset. MOST generally underestimates 2011 peak current velocities by about 10-30 %, with a few peaks by as much as 50 %. At Humboldt Bay, MOST predicted attenuation of the signal after 4 h but the actual signal persisted at a nearly constant level for at least twice as long. The results from this project demonstrate that ADCPs can effectively record tsunami currents for small to moderate events and can be used to calibrate and validate models (i.e., MOST) in order to better understand hazardous tsunami conditions within harbors.

Admire, Amanda R.; Dengler, Lori A.; Crawford, Gregory B.; Uslu, Burak U.; Borrero, Jose C.; Greer, S. Dougal; Wilson, Rick I.

2014-12-01

234

CARBON DIOXIDE SEQUESTRATION IN TERRESTRIAL ECOSYSTEMS  

EPA Science Inventory

The terrestrial biosphere plays a prominent role in the global carbon (C) cycle. errestrial ecosystems are currently accumulating C and it appears feasible to manage existing terrestrial (forest, agronomic, desert) ecosystems to maintain or increase C storage. orest ecosystems ca...

235

Seasonal to Decadal-Scale Variability in Satellite Ocean Color and Sea Surface Temperature for the California Current System  

NASA Technical Reports Server (NTRS)

Support for this project was used to develop satellite ocean color and temperature indices (SOCTI) for the California Current System (CCS) using the historic record of CZCS West Coast Time Series (WCTS), OCTS, WiFS and AVHRR SST. The ocean color satellite data have been evaluated in relation to CalCOFI data sets for chlorophyll (CZCS) and ocean spectral reflectance and chlorophyll OCTS and SeaWiFS. New algorithms for the three missions have been implemented based on in-water algorithm data sets, or in the case of CZCS, by comparing retrieved pigments with ship-based observations. New algorithms for absorption coefficients, diffuse attenuation coefficients and primary production have also been evaluated. Satellite retrievals are being evaluated based on our large data set of pigments and optics from CalCOFI.

Mitchell, B. Greg; Kahru, Mati; Marra, John (Technical Monitor)

2002-01-01

236

Spatial and Temporal Scales of Recent Turbidity Currents in Monterey Submarine Canyon, California  

NASA Astrophysics Data System (ADS)

Turbidity currents are responsible for transporting and depositing most of the sand and other coarse clastic sediment to deep-sea fans and deltas, and for creating and maintaining the omnipresent submarine channels on the continental slope. The temporal and spatial scales (duration, speed, and run-out distance) of turbidity currents have always been of keen interest to geologists because of their importance in determining the size and distribution of turbidites - deposits formed by turbidity currents. Here we present in-situ velocity and turbidity data of modern-day turbidity currents measured in Monterey Submarine Canyon during 2002 - 2011. The experiments co-conducted by the U.S. Geological Survey and the Monterey Bay Aquarium Research Institute were among the first studies specifically designed to measure field scale turbidity currents, which have provided by far the most complete picture of any marine turbidity current. Concurrent measurements from downward-looking ADCPs at multiple locations along the canyon provided high-resolution velocity profiles of the turbidity currents. Temperature and turbidity sensors above the ADCPs recorded the time of arrival and the duration of the turbidity currents. These high-resolution, high-frequency data allowed us to quantitatively characterize the bulk properties (maximum speed, thickness, density, etc) and their along-canyon evolution. The measured properties of field turbidity currents are used to examine the validity of empirical relationships obtained from theoretical analysis and laboratory experiments. The correlations between these properties and the lateral size (run-out distance) and the autosuspension criteria are also discussed.

Xu, J.; Paull, C. K.; Barry, J. P.; Noble, M. A.

2011-12-01

237

Seasonal and spatial variation of bug flux in a northern California drainage network under a Mediterranean climate: implications for reciprocal subsidies between coupled ecosystems  

NASA Astrophysics Data System (ADS)

Background/Question/Methods. Network configuration of river drainages affects ecological exchange between mainstem channels and smaller tributaries, and between coupled terrestrial and aquatic habitats. Seasonal complementarity of fluxes may enhance predator densities and persistence in linked habitats under continental climate regimes (Nakano and Murakami 2001). In a Mediterranean watershed (the upper South Fork Eel River of Northern California (39°44’N, 123°37’W)), we studied spatial and seasonal patterns in insect fluxes among river, wetland, and forest habitats. We quantified insect emergence with vertical traps, and lateral fluxes between six wetland and eight river reaches and the upland forest adjacent to each. Insect horizontal fluxes were sampled using sticky traps along 50-150 m transects from the moister to the dryer habitats. We also studied vertical gradients of insect fluxes over rivers (up to 7 m) and in the forest (up to 40 m). Ca. 1800 traps and 40,000 insects were quantified. Results/Conclusions. In contrast to linked forest-river ecosystems in Hokkaido, peaks of insect fluxes in aquatic versus terrestrial habitats of the Eel River basin were less offset, and the seasonality of terrestrial versus river peaks was reversed. From late April through May, when the whole landscape was moist, there was no spatial variation in insect abundance-activity along forest, wetland, or river transects, and abundances averaged 315 insects m-2d-1. As the uplands dried out, from June to September, insect abundance peaked in wetlands and near the river, but dropped in the forest to average 32 insects m-2d-1 . The wetlands, with three abundance peaks distributed through spring, summer, and fall, maintained insect fluxes when river and forest fluxes were low. Vertically arrayed sticky traps over the river documented maximal insect activity-abundance near the water surface. In some positions, movements appeared random (equal downstream and upstream fluxes), but at other sites movements were strongly directional. For example, Amaletus mayflies that reared as larvae in the productive mainstem swarmed as adults into a small, dark, steep tributary, where extensive crusts of dead adults over tributary pools suggested that they mated and died. We are investigating how insectivorous birds and bats track and respond to these seasonal shifts in food supply points and spatial fluxes through the basin network of linked habitats.

Power, M. E.; Moreno-Mateos, D.; Uno, H.; Bode, C.; Rainey, W.

2010-12-01

238

California Snowpack  

NSDL National Science Digital Library

Provided by the California Cooperative Snow Surveys in conjunction with the California Department of Water Resources, this site contains an interactive map and links for selecting riverbasins for which data are supplied. Within each riverbasin area, current data are available by station name. Users may obtain snow, water content, rain, and temperature readings in plot or table form.

239

Kaiser Permanente Northern California: current experiences with internet, mobile, and video technologies.  

PubMed

The US health care system has been slow to adopt Internet, mobile, and video technologies, which have the capability to engage patients in their own care, increase patients' access to providers, and possibly improve the quality of care while reducing costs. Nevertheless, there are some pockets of progress, including Kaiser Permanente Northern California (KPNC). In 2008 KPNC implemented an inpatient and ambulatory care electronic health record system for its 3.4 million members and developed a suite of patient-friendly Internet, mobile, and video tools. KPNC has achieved many successes. For example, the number of virtual "visits" grew from 4.1 million in 2008 to an estimated 10.5 million in 2013. This article describes KPNC's experience with Internet, mobile, and video technologies and the obstacles faced by other health care providers interested in embracing them. The obstacles include the predominant fee-for-service payment model, which does not reimburse for virtual visits; the considerable investment needed to deploy these technologies; and physician buy-in. PMID:24493768

Pearl, Robert

2014-02-01

240

Ecosystem Explorations  

NSDL National Science Digital Library

The Ecosystem Explorations curriculum includes eleven classroom lessons. The lessons are divided into two sections--Understanding Ecosystems and Human Connections to Ecosystems. The curriculum incorporates scientific inquiry skills, cooperative l

Kristen L. Gunckel

1999-09-01

241

Climatic Impacts and resilience of coastal ecosystems and fisheries  

NASA Astrophysics Data System (ADS)

Marine and coastal ecosystems and human communities around the world are impacted by local anthropogenic pressures and by climate change, resulting in decreased ocean productivity, altered food web dynamics, habitat degradation, economic losses, and health and safety risks as a consequence of the changing and more variable climate. Climatic impacts occur both through altered physical conditions and variability, e.g., seawater temperature and sea level, and through a suite of chemical changes, including ocean acidification and hypoxia. In particular, time series analyses have highlighted declines in dissolved oxygen (DO) concentration in the ocean over the last several decades. In addition to these global trends of decreasing DO, hypoxic conditions have been documented at several coastal locations within productive upwelling-driven ecosystems, including the California Current region, resulting in high mortality of ecologically and commercially important nearshore marine species and significant economic losses. The capacity of local ecosystems and associated human communities to adapt to these pressures depends on their resilience, that is the ability of ecosystems to absorb disturbance while retaining function and continuing to provide ecosystem services, and the ability of people to adapt to change in their environment by altering their behaviors and interactions. I will present global assessments of the cumulative impacts of climatic and local anthropogenic pressures on marine ecosystems, and results of interdisciplinary research investigating the current impacts of climate change on coastal marine ecosystems and human communities of the Pacific coast of Baja California, Mexico, and the influences of local and global feedbacks on the resilience and adaptive capacity of these systems.

Micheli, F.

2012-12-01

242

Facilitating Next Generation Science Collaboration: Respecting and Mediating Vocabularies with Semantics in Ecosystems Assessments.  

NASA Astrophysics Data System (ADS)

A newly funded initiative is developing and deploying an integrated ecosystem assessment (IEA) system using an information science and semantic technologies. The intention is to advance the capacity of an IEA to provide the foundation for synthesis and quantitative analysis of natural and socio-economic ecosystem information to support ecosystem-based management. In particular, the initiative is create the capacity to assess the impacts of changing climate on two large marine ecosystems: the northeast U.S. and the California Current. These assessments will be essential parts of the science-based decision-support tools used to develop adaptive management measures. Enhanced collaboration is required to achieve these goals: interaction and information sharing within and among diverse data providers, analysis tool developers and user groups that constitute the broader coastal and marine ecosystem science application community. This presentation indicates how semantic solutions are fundamental to this initiative.

Fox, P. A.; Maffei, A. R.; Ecoop Team

2011-12-01

243

Freshwater influences on productivity, retention, and export in the northern California Current System (Invited)  

NASA Astrophysics Data System (ADS)

The U.S. Pacific Northwest coastal ecosystem is, like other highly productive eastern boundary systems, fueled primarily by the upwelling of deep oceanic nutrients, and it has traditionally been assumed that the strength and fate of biological production was regulated primarily by alongcoast wind stress. Here we synthesize results from three recent large programs (NSF RISE, NOAA ECOHAB PNW, and NSF/NOAA PNWTOX) to describe the variety of ways in which river plume dynamics and estuarine circulation complicate this picture. First, the Fraser River and other rivers of the inland Salish Sea amplify primary prodution on the regional scale not only by directly supplying a modest load of terrestrial nutrients, but also, more important, by driving a persistent estuarine circulation in the Strait of Juan de Fuca that approximately doubles the provision of oceanic nutrients to the shelf. Second, the increased stratification associated with the Columbia River plume increases cross-shelf export on the regional scale, such that 10-20% of total primary production is shifted from the inner shelf to the outer shelf and slope, where carbon export in the vertical sense is likely to be much more efficient. Finally, both river systems increase retention in the alongcoast direction--the Salish Sea outflow through the formation of the persistent Juan de Fuca eddy, and the Columbia River plume by amplifying the surface-layer response to intervals of downwelling winds--leading to older plankton communities and increased transfer to higer trophic levels. These freshwater-driven mechanisms suggest alternate lines of connection between global climate forcing and regional carbon export, beyond the traditional focus on the coastal wind field.

Banas, N. S.; Hickey, B. M.

2010-12-01

244

Sierra Nevada Ecosystem Project: Final report to Congress, vol. II, Assessments and scientific basis for management options. Davis: University of California, Centers for Water and Wildland Resources, 1996.  

E-print Network

elevations; and (4) Sierra Nevada fisheries have largely shifted from native fishes, especially salmon, 1996. PETER B. MOYLE Department of Wildlife, Fish, and Conservation Biology University of California Davis, California RONALD M. YOSHIYAMA Department of Wildlife, Fish, and Conservation Biology University

Knapp, Roland

245

Ocean warming and seabird communities of the southern California Current System (1987-98): response at multiple temporal scales  

NASA Astrophysics Data System (ADS)

Declines in ocean productivity and shifts in species assemblages along the West Coast of North America during the second half of the XXth century have been attributed to the concurrent warming of the California Current. This paper addresses changes in the avifauna off southern California between May 1987 and September 1998, in response to shifting water mass distributions over short (<1 year) and long (interannual) temporal scales. More specifically, our research focuses on the relative importance of distinct foraging guilds and species assemblages with an affinity for warm and cold water. Over the long term, the avifauna off southern California shifted from a 'high-productivity' community typical of eastern boundary upwelling systems, to a 'low-productivity' assemblage similar to those inhabiting the subtropical gyres. Overall seabird abundance decreased; the relative importance of cold-water seabirds that dive in pursuit of prey declined; and warm-water species that feed at the surface and plunge to capture prey became more numerous. These community-level changes are consistent with the northward shifts in species ranges and the declining ocean productivity anticipated as a result of global warming. However, the response of individual taxa with an affinity for warm-water and cold-water conditions has been more difficult to predict, due to differences in species-specific responses to ocean warming. The three cold-water species investigated (Sooty Shearwater Puffinus griseus, Cassin's Auklet Ptychoramphus aleuticus, and Rhinoceros Auklet Cerorhinca monocerata) decreased in abundance during this study. On the other hand, only one of the six warm-water species considered (Pink-footed Shearwater, Puffinus creatopus) increased significantly over the long term. Yet, the warm-water Leach's Storm-petrel ( Oceanodroma leucorhoa) increased between 1987 and 1993, and then declined between 1994 and 1998. Moreover, cross-correlations between seasonally adjusted anomalies of bird abundance and ocean temperature revealed that seabirds responded differently to ocean warming over intermediate (1-8 years), and long (8-12 years) time scales. We hypothesize that this nonlinear behavior of seabird populations in response to ocean warming is caused by the juxtaposition of distinct behavioral and demographic responses operating at different temporal scales.

Hyrenbach, K. David; Veit, Richard R.

2003-08-01

246

What Is Ecosystem Management?  

Microsoft Academic Search

The evolving concept of ecosystem management is the focus of much current debate. To clarify discussion and provide a frammork for implementatiotq I trace the histor- ical development of ecosystem management, provide a working definitioq and summarize dominant themes taken from an extensive literature reuiew. The general goal of maintaining ecological integ?Yty is discussed along with five specific goals: maintaining

R. Edward Grumbine

1994-01-01

247

Coastal iron and nitrate distributions during the spring and summer upwelling season in the central California Current upwelling regime  

NASA Astrophysics Data System (ADS)

Distributions of iron and nitrate in the central California Current System upwelling regime (cCCS) from 34 to 41°N were determined during cruises in May 2010 and August 2011. High spatial and temporal resolution data for dissolved Fe and NO3- (nitrate+nitrite) in the cCCS from this study greatly expands upon previous studies that were narrower in scope (e.g., focused on just the Monterey Bay region). Shelf sediments from mid-shelf mud belts in this region provide the dominant source of Fe, and there are areas in the cCCS where insufficient Fe is upwelled to accompany elevated levels of other macronutrients (nitrate, phosphate, silicate) to fuel extensive diatom blooms. Surface dissolved Fe concentrations were related to continental shelf width and upwelling strength, and surface Fe concentrations tended to be lower in the late summer than early spring. We present extensive benthic boundary layer (BBL) dissolved and leachable particulate Fe data from both seasons in the mid-shelf region along the central California coast. Leachable particulate Fe concentrations were strongly related to the width of the mid-shelf mud belts (i.e., the continental shelf between the 50 and 90 m isobaths). Dissolved Fe concentrations in the BBL over the mid-shelf were generally highest in wide mud belt areas as well as in areas with very low dissolved oxygen concentrations but did not show a clear seasonal trend. Evidence for probable Fe limitation in upwelled waters was found by using surface dissolved Fe:NO3- ratios and the estimated specific growth rate of coastal diatoms based on either Fe or NO3- concentrations. Several coastal upwelling regions with only moderate to narrow continental shelves (Pt. Arena to Cape Mendocino and the Big Sur Coast) exhibited evidence for Fe limitation in both the spring and summer upwelling seasons.

Biller, Dondra V.; Coale, Tyler H.; Till, Ralph C.; Smith, Geoffrey J.; Bruland, Kenneth W.

2013-09-01

248

Water Management Adaptations for Aquatic Ecosystem Services Under a Changing Climate. Analytical Framework and Case Study for Chinook Salmon in California  

NASA Astrophysics Data System (ADS)

Spring-run Chinook salmon (Oncorhynchus tshawytscha) are vulnerable to climate change because, before spawning in autumn, adults hold in river pools where temperature increases during summer. As these species naturally experience temperatures close to tolerable thresholds, climate-induced flow and temperature changes can increase their vulnerability. Our objective was to assemble an analytical framework to assess temperature and streamflow thresholds that would lead to critical reductions in spring-run Chinook salmon abundance, and to evaluate management adaptations to ameliorate these impacts. The analytical framework coupled climate data with watershed hydrology and salmon population dynamics models. We used WEAP, an integrated watershed hydrology, water management, and temperature model; and SALMOD, a spatially explicit and size/stage structured model that predicts population dynamics of salmon in freshwater systems. The models simulated weekly mean streamflow, temperature, and salmon abundance in Butte Creek, California. We calibrated and validated the models to adequately fit historical data. With the analytical framework built, we used bias-corrected and spatially downscaled climate data from six General Circulation Models and two emission scenarios for the period 2010 - 2099 to run the two linked models, and generated a range of potential future outcomes. WEAP predicted that summer base flows were lower, and water temperatures were higher for climate scenarios vs. historical conditions. SALMOD predicted increased summer thermal mortality of adult salmon; the population was predicted to decline for all climate scenarios and model combinations. We tested management adaptations, including cessation of water diverted for power production, and storage of cold reservoir water upstream for release during hot weather. Some adaptations resulted in cooler temperatures, more adults surviving to spawn, and extended population survival time. The coupled models, together with climate data, constitute a framework able to predict streamflow- and temperature-related mortality of spring-run Chinook salmon, and to evaluate water management adaptations to ameliorate negative climate impacts on fish in current or future scenarios.

Escobar, M.; Mosser, C. M.; Thompson, L. C.; Purkey, D.; Moyle, P. B.

2010-12-01

249

Evaluating Cumulative Ecosystem Evaluating Cumulative Ecosystem Response of the Columbia River Response of the Columbia River  

E-print Network

Evaluating Cumulative Ecosystem Evaluating Cumulative Ecosystem Response of the Columbia River Response of the Columbia River Estuary Ecosystem to Past and Estuary Ecosystem to Past and Current metrics and ecosystem state resulting from cumulative restoration impacts. 2 #12;Managers Want Answers

250

Estimating suspended solids concentrations from backscatter intensity measured by acoustic Doppler current profiler in San Francisco Bay, California  

USGS Publications Warehouse

The estimation of mass concentration of suspended solids is one of the properties needed to understand the characteristics of sediment transport in bays and estuaries. However, useful measurements or estimates of this property are often problematic when employing the usual methods of determination from collected water samples or optical sensors. Analysis of water samples tends to undersample the highly variable character of suspended solids, and optical sensors often become useless from biological fouling in highly productive regions. Acoustic sensors, such as acoustic Doppler current profilers that are now routinely used to measure water velocity, have been shown to hold promise as a means of quantitatively estimating suspended solids from acoustic backscatter intensity, a parameter used in velocity measurement. To further evaluate application of this technique using commercially available instruments, profiles of suspended solids concentrations are estimated from acoustic backscatter intensity recorded by 1200- and 2400-kHz broadband acoustic Doppler current profilers located at two sites in San Francisco Bay, California. ADCP backscatter intensity is calibrated using optical backscatterance data from an instrument located at a depth close to the ADCP transducers. In addition to losses from spherical spreading and water absorption, calculations of acoustic transmission losses account for attenuation from suspended sediment and correction for nonspherical spreading in the near field of the acoustic transducer. Acoustic estimates of suspended solids consisting of cohesive and noncohesive sediments are found to agree within about 8-10% (of the total range of concentration) to those values estimated by a second optical backscatterance sensor located at a depth further from the ADCP transducers. The success of this approach using commercially available Doppler profilers provides promise that this technique might be appropriate and useful under certain conditions in spite of some theoretical limitations of the method. ?? 2004 Elsevier B.V. All rights reserved.

Gartner, J.W.

2004-01-01

251

Air-sea CO2 fluxes in the California Current: Impacts of model resolution and coastal topography  

NASA Astrophysics Data System (ADS)

The present study uses a suite of coupled physical-biogeochemical model simulations at 1/3°, 1/10°, and 1/30° to assess the impact of horizontal resolution on air-sea CO2 fluxes in the California Current System (CCS), a relevant issue for downscaling between coarser resolution global climate models and higher resolution regional models. The results demonstrate that horizontal resolution is important to reproduce the sharp transition between near-shore outgassing and offshore absorption, as well as to resolve regions of enhanced near-shore outgassing in the lee of capes. The width of the outgassing region is overestimated when horizontal resolution is not eddy resolving (i.e., 1/3°) but becomes more dependent on shelf topography for eddy-resolving simulations (i.e., 1/10° and 1/30°). Enhanced near-shore outgassing is associated with a local increase in wind-driven upwelling in the lee of capes (i.e., expansion fans), meaning that sufficient horizontal resolution is needed both in the ocean circulation model and in the wind field forcing the model. From a global carbon budget perspective, the model indicates that biological production generates sufficient absorption within a few hundred kilometers of the coast to offset near-shore outgassing, which is consistent with the notion that midlatitude eastern boundary current upwelling systems act both as a sink and source for atmospheric CO2. Based on the 1/30° solution, the CCS between 35 and 45 N and out to 600 km offshore is a net carbon sink of approximately 6 TgC yr-1, with the 1/10° solution underestimating this value by less than 10% and the 1/3° solution by a factor of 3.

Fiechter, Jerome; Curchitser, Enrique N.; Edwards, Christopher A.; Chai, Fei; Goebel, Nicole L.; Chavez, Francisco P.

2014-04-01

252

Long-term trends and variability in the larvae of Pacific sardine and associated fish species of the California Current region  

NASA Astrophysics Data System (ADS)

Fifty-year ichthyoplankton and oceanographic time series of the California Cooperative Oceanic Fisheries Investigations were used to describe changes in larval fish abundance and associated habitat features in the Southern California Bight region, extending seaward to the limits of the California Current. The ichthyoplankton data set for this analysis was based on single tows taken at all CalCOFI survey stations occupied within the current sampling pattern from 1951 to 2000 and consisted of a total of 11,917 samples from which 1,365,988 fish larvae were identified. The analysis included data on habitat temperature, macrozooplankton volumes, and 14 taxa of larval fishes, some of commercial interest (Pacific sardine, Pacific hake, Pacific and jack mackerel, and rockfishes), and a group of important mesopelagic species that represent specific habitats in the California Current region. Data are presented in a series of graphs showing changes in average abundance, triennial abundance ratios, and normalized quarterly abundance (1988-2000 only). Larval data clearly track the decline and recovery of the Pacific sardine population. Mesopelagic larvae of southern offshore species had the greatest response to the regime shift of 1976-77, increasing markedly in the Southern California Bight region after 1977. Likewise, this group of species showed the greatest response to the 1957-59 El Niño. There was no consistent response in larval abundance of Subarctic-Transitional mesopelagic species and nearshore taxa to the 1976-77 regime shift. Most of the species showed a negative shift in triennial larval abundance ratios in relation to hypothesized 1989-90 and 1998-99 regime shifts. These changes are discussed in relation to changes in temperature and macrozooplankton volumes.

Smith, Paul E.; Moser, H. Geoffrey

2003-08-01

253

Spring-time distributions of migratory marine birds in the southern California Current: Oceanic eddy associations and coastal habitat hotspots over 17 years  

NASA Astrophysics Data System (ADS)

We used a 17-year time series of shipboard observations to address the hypothesis that marine birds associate with persistent hydrographic features in the southern California Current System (CCS). Overall, approximately 27,000 km of ocean habitat were surveyed, averaging 1600 km per cruise. We identified mesoscale features (eddy centers and the core of the California Current), based on dynamic height anomalies, and considered habitat associations for seven migratory seabird species: black-footed albatross ( Phoebastria nigripes), Cook's petrel ( Pterodroma cookii), Leach's storm-petrel ( Oceanodroma leucorhoa), dark shearwaters (mainly sooty shearwater Puffinus griseus, with a few short-tailed shearwaters Puffinus tenuirostris), northern fulmar ( Fulmarus glacialis), red phalarope ( Phalaropus fulicaria), and red-necked phalarope ( Phalaropus lobatus). We explored associations (presence/absence and density relationships) of marine birds with mesoscale features (eddies, current jet) and metrics of primary productivity (chlorophyll a and nitrate concentrations). Mesoscale eddies were consistently identified in the study region, but were spatially and temporally variable. The resolved eddies were large-scale features associated with meanders of the equatorward-flowing California Current. Cook's petrel was found offshore with no specific habitat affinities. Black-footed albatross, red phalarope, and Leach's storm petrel were found in association with offshore eddies and/or the core of the California Current, but the functional relationship for these species varied, possibly reflecting differences in flight capabilities. The more coastal species, including the shearwaters, fulmar, and red-necked phalarope, were positively associated with proxies of primary productivity. Of the hydrographic habitats considered, the upwelling region of Point Conception appears to be an important "hotspot" of sustained primary production and marine bird concentrations. Point Conception and other similar coastal locations (upwelling cells) may warrant protection as key foraging grounds for seabirds.

Yen, P. P. W.; Sydeman, W. J.; Bograd, S. J.; Hyrenbach, K. D.

2006-02-01

254

Analysis of projected water availability with current basin management plan, Pajaro Valley, California  

NASA Astrophysics Data System (ADS)

The projection and analysis of the Pajaro Valley Hydrologic Model (PVHM) 34 years into the future using MODFLOW with the Farm Process (MF-FMP) facilitates assessment of potential future water availability. The projection is facilitated by the integrated hydrologic model, MF-FMP that fully couples the simulation of the use and movement of water from precipitation, streamflow, runoff, groundwater flow, and consumption by natural and agricultural vegetation throughout the hydrologic system at all times. MF-FMP allows for more complete analysis of conjunctive-use water-resource systems than previously possible with MODFLOW by combining relevant aspects of the landscape with the groundwater and surface-water components. This analysis is accomplished using distributed cell-by-cell supply-constrained and demand-driven components across the landscape within “water-balance subregions” (WBS) comprised of one or more model cells that can represent a single farm, a group of farms, watersheds, or other hydrologic or geopolitical entities. Analysis of conjunctive use would be difficult without embedding the fully coupled supply-and-demand into a fully coupled simulation, and are difficult to estimate a priori. The analysis of projected supply and demand for the Pajaro Valley indicate that the current water supply facilities constructed to provide alternative local sources of supplemental water to replace coastal groundwater pumpage, but may not completely eliminate additional overdraft. The simulation of the coastal distribution system (CDS) replicates: 20 miles of conveyance pipeline, managed aquifer recharge and recovery (MARR) system that captures local runoff, and recycled-water treatment facility (RWF) from urban wastewater, along with the use of other blend water supplies, provide partial relief and substitution for coastal pumpage (aka in-lieu recharge). The effects of these Basin Management Plan (BMP) projects were analyzed subject to historical climate variations and assumptions of 2009 urban water demand and land use. Water supplied directly from precipitation, and indirectly from reuse, captured local runoff, and groundwater is necessary but inadequate to satisfy agricultural demand without coastal and regional storage depletion that facilitates seawater intrusion. These facilities reduce potential seawater intrusion by about 45% with groundwater levels in the four regions served by the CDS projected to recover to levels a few feet above sea level. The projected recoveries are not high enough to prevent additional seawater intrusion during dry-year periods or in the deeper aquifers where pumpage is greater. While these facilities could reduce coastal pumpage by about 55% of the historical 2000-2009 pumpage for these regions, and some of the water is delivered in excess of demand, other coastal regions continue to create demands on coastal pumpage that will need to be replaced to reduce seawater intrusion. In addition, inland urban and agricultural demands continue to sustain water levels below sea level causing regional landward gradients that also drive seawater intrusion. Seawater intrusion is reduced by about 45% but it supplies about 55% of the recovery of groundwater levels in the coastal regions served by the CDS. If economically feasible, water from summer agricultural runoff and tile-drain returnflows could be another potential local source of water that, if captured and reused, could offset the imbalance between supply and demand as well as reducing discharge of agricultural runoff into the National Marine Sanctuary of Monterey Bay. A BMP update (2012) identifies projects and programs that will fund a conservation program and will provide additional, alternative water sources to reduce or replace coastal and inland pumpage, and to replenish the aquifers with managed aquifer recharge in an inland portion of the Pajaro Valley.

Hanson, R. T.; Lockwood, B.; Schmid, Wolfgang

2014-11-01

255

Florida Ecosystems  

NSDL National Science Digital Library

Provided by FICUS (the Florida Internet Center for Understanding Sustainability) and the University of South Florida, this gem of a site covers Florida's native upland, freshwater, and marine ecosystems. Streamlined in organization but solid in content, Florida Ecosystems offers introductory information and photographic images of a dozen ecosystems, ranging from Pine Flatwoods and Dry Prairies to Mangrove Swamps and Coral Reefs. For students and educators interested in subtropical ecosystems, this is a nice place to start.

256

Ecosystem Journalism  

ERIC Educational Resources Information Center

If the organisms in a prairie ecosystem created a newspaper, what would it look like? What important news topics of the ecosystem would the organisms want to discuss? Imaginative and enthusiastic third-grade students were busy pondering these questions as they tried their hands at "ecosystem journalism." The class had recently completed a study of…

Robertson, Amy; Mahlin, Kathryn

2005-01-01

257

Ecosystem Jenga!  

ERIC Educational Resources Information Center

To give students a tangible model of an ecosystem and have them experience what could happen if a component of that ecosystem were removed; the authors developed a hands-on, inquiry-based activity that visually demonstrates the concept of a delicately balanced ecosystem through a modification of the popular game Jenga. This activity can be…

Umphlett, Natalie; Brosius, Tierney; Laungani, Ramesh; Rousseau, Joe; Leslie-Pelecky, Diandra L.

2009-01-01

258

Spatial analysis of plague in California: niche modeling predictions of the current distribution and potential response to climate change  

Microsoft Academic Search

BACKGROUND: Plague, caused by the bacterium Yersinia pestis, is a public and wildlife health concern in California and the western United States. This study explores the spatial characteristics of positive plague samples in California and tests Maxent, a machine-learning method that can be used to develop niche-based models from presence-only data, for mapping the potential distribution of plague foci. Maxent

Ashley C Holt; Daniel J Salkeld; Curtis L Fritz; James R Tucker; Peng Gong

2009-01-01

259

Carbon and Nitrogen Isotopes from Top Predator Amino Acids Reveal Rapidly Shifting Ocean Biochemistry in the Outer California Current  

PubMed Central

Climatic variation alters biochemical and ecological processes, but it is difficult both to quantify the magnitude of such changes, and to differentiate long-term shifts from inter-annual variability. Here, we simultaneously quantify decade-scale isotopic variability at the lowest and highest trophic positions in the offshore California Current System (CCS) by measuring ?15N and ?13C values of amino acids in a top predator, the sperm whale (Physeter macrocephalus). Using a time series of skin tissue samples as a biological archive, isotopic records from individual amino acids (AAs) can reveal the proximate factors driving a temporal decline we observed in bulk isotope values (a decline of ?1 ‰) by decoupling changes in primary producer isotope values from those linked to the trophic position of this toothed whale. A continuous decline in baseline (i.e., primary producer) ?15N and ?13C values was observed from 1993 to 2005 (a decrease of ?4‰ for ?15N source-AAs and 3‰ for ?13C essential-AAs), while the trophic position of whales was variable over time and it did not exhibit directional trends. The baseline ?15N and ?13C shifts suggest rapid ongoing changes in the carbon and nitrogen biogeochemical cycling in the offshore CCS, potentially occurring at faster rates than long-term shifts observed elsewhere in the Pacific. While the mechanisms forcing these biogeochemical shifts remain to be determined, our data suggest possible links to natural climate variability, and also corresponding shifts in surface nutrient availability. Our study demonstrates that isotopic analysis of individual amino acids from a top marine mammal predator can be a powerful new approach to reconstructing temporal variation in both biochemical cycling and trophic structure. PMID:25329915

Ruiz-Cooley, Rocio I.; Koch, Paul L.; Fiedler, Paul C.; McCarthy, Matthew D.

2014-01-01

260

Water, Energy, and Ecosystems: A Case Study of California's Sierra Nevada to Assess Vulnerability to Climate Change and Opportunities for Adaptation  

Microsoft Academic Search

We report here on a major effort to define and quantify metrics of vulnerability to climate change for the west-slope of California's Sierra Nevada. We have defined the vulnerability of flowing surface waters used for human and ecological purposes as a function of exposure and sensitivity to anticipated hydrologic alteration mediated by regional climate warming and as measured by changes

J. H. Viers; S. Null; S. T. Ligare; D. E. Rheinheimer; J. N. Williams

2010-01-01

261

Ecosystem consequences of fish parasites  

Microsoft Academic Search

In most aquatic ecosystems, fishes are hosts to parasites and, sometimes, these parasites can affect fish biology. Some of the most dramatic cases occur when fishes are intermediate hosts for larval parasites. For example, fishes in southern California estuaries are host to many parasites. The most common of these parasites, Euhaplorchis californiensis, infects the brain of the killifish Fundulus parvipinnis

K. D. Lafferty

2008-01-01

262

Seasonal and spatial variation of bug flux in a northern California drainage network under a Mediterranean climate: implications for reciprocal subsidies between coupled ecosystems  

Microsoft Academic Search

Background\\/Question\\/Methods. Network configuration of river drainages affects ecological exchange between mainstem channels and smaller tributaries, and between coupled terrestrial and aquatic habitats. Seasonal complementarity of fluxes may enhance predator densities and persistence in linked habitats under continental climate regimes (Nakano and Murakami 2001). In a Mediterranean watershed (the upper South Fork Eel River of Northern California (39°44'N, 123°37'W)), we studied

M. E. Power; D. Moreno-Mateos; H. Uno; C. Bode; W. Rainey

2010-01-01

263

Spatiotemporal variability and drivers of pCO2 and air-sea CO2 fluxes in the California Current System: an eddy-resolving modeling study  

NASA Astrophysics Data System (ADS)

We quantify the CO2 source/sink nature of the California Current System (CalCS) and determine the drivers and processes behind the mean and spatiotemporal variability of the partial pressure of CO2 (pCO2) in the surface ocean. To this end, we analyze eddy-resolving, climatological simulations of a coupled physical-ecosystem-biogeochemical ocean model on the basis of the Regional Oceanic Modeling System (ROMS). The model-simulated pCO2 agrees very well with in situ observations over the entire domain with virtually no bias, but the model overestimates pCO2 in the nearshore 100 km, and underestimates the observed temporal variability. In the annual mean, the entire CalCS within 800 km of the coast and from ~ 33° N to 46° N is essentially neutral with regard to atmospheric CO2. The model simulates an integrated uptake flux of -0.9 Tg C yr-1, corresponding to a very small average flux density of -0.05 mol C m-2 yr-1, with an uncertainty of the order of ±0.20 mol C m-2 yr-1. This near zero flux is a consequence of an almost complete regional compensation between the strong outgassing in the nearshore region (first 100 km), with flux densities of more than 3 mol C m-2 yr-1 and a weaker, but more widespread uptake flux in the offshore region with an average flux density of -0.17 mol C m-2 yr-1. This pattern is primarily a result of the interaction between upwelling in the nearshore that brings waters with high concentrations of dissolved inorganic carbon (DIC) to the surface, and an intense biological drawdown of this DIC, driven by the nutrients that are upwelled together with the DIC. The biological drawdown occurs too slowly to prevent the escape of a substantial amount of CO2 into the atmosphere, but this is compensated by the biological generation of undersaturated conditions offshore of 100 km, permitting the CalCS to take up most of the escaped CO2. Thus, the biological pump over the entire CalCS is essentially 100% efficient, making the preformed DIC and nutrient concentrations of the upwelled waters a primary determinant of the overall source/sink nature of the CalCS. The comparison of the standard simulation with one for preindustrial conditions show that the CalCS is taking up anthropogenic CO2 at a rate of about -1 mol C m-2 yr-1, implying that the region was a small source of CO2 to the atmosphere in preindustrial times. The air-sea CO2 fluxes vary substantially in time, both on seasonal and sub-seasonal timescales, largely driven by variations in surface ocean pCO2. There are important differences among the subregions. Notably, the total variance of the fluxes in the central nearshore CalCS is roughly 4-5 times larger than elsewhere. Most of the variability in pCO2 is associated with the seasonal cycle, except in the nearshore, where sub-seasonal variations driven by mesoscale processes dominate. In the regions offshore of 100 km, changes in surface temperature are the main driver, while in the nearshore region, changes in surface temperature, as well as anomalies in DIC and alkalinity (Alk) owing to changes in circulation, biological productivity and air-sea CO2 fluxes dominate. The dominance of eddy-driven variability in the nearshore 100 km leads to a complex spatiotemporal mosaic of surface ocean pCO2 and air-sea CO2 fluxes that require a substantial observational effort to determine the source/sink nature of this region reliably.

Turi, G.; Lachkar, Z.; Gruber, N.

2013-08-01

264

Ecosystem Health in Mineralized Terrane-Data from Podiform Chromite (Chinese Camp Mining District, California), Quartz Alunite (Castle Peak and Masonic Mining Districts, Nevada/California), and Mo/Cu Porphyry (Battle Mountain Mining District, Nevada) Deposits  

USGS Publications Warehouse

The myriad definitions of soil/ecosystem quality or health are often driven by ecosystem and management concerns, and they typically focus on the ability of the soil to provide functions relating to biological productivity and/or environmental quality. A variety of attempts have been made to create indices that quantify the complexities of soil quality and provide a means of evaluating the impact of various natural and anthropogenic disturbances. Though not without their limitations, indices can improve our understanding of the controls behind ecosystem processes and allow for the distillation of information to help link scientific and management communities. In terrestrial systems, indices were initially developed and modified for agroecosystems; however, the number of studies implementing such indices in nonagricultural systems is growing. Soil quality indices (SQIs) are typically composed of biological (and sometimes physical and chemical) parameters that attempt to reduce the complexity of a system into a metric of a soil's ability to carry out one or more functions. The indicators utilized in SQIs can be as varied as the studies themselves, reflecting the complexity of the soil and ecosystems in which they function. Regardless, effective soil quality indicators should correlate well with soil or ecosystem processes, integrate those properties and processes, and be relevant to management practices. Commonly applied biological indicators include measures associated with soil microbial activity or function (for example, carbon and nitrogen mineralization, respiration, microbial biomass, enzyme activity. Cost, accessibility, ease of interpretation, and presence of existing data often dictate indicator selection given the number of available measures. We employed a large number of soil biological, chemical, and physical measures, along with measures of vegetation cover, density, and productivity, in order to test the utility and sensitivity of these measures within various mineralized terranes. We were also interested in examining these relations in the context of determining appropriate reference conditions with which to compare reclamation efforts. The purpose of this report is to present the data used to develop indices of soil and ecosystem quality associated with mineralized terranes (areas enriched in metal-bearing minerals), specifically podiform chromite, quartz alunite, and Mo/Cu porphyry systems. Within each of these mineralized terranes, a nearby unmineralized counterpart was chosen for comparison. The data consist of soil biological, chemical, and physical parameters, along with vegetation measurements for each of the sites described below. Synthesis of these data and index development will be the subject of future publications.

Blecker, Steve W.; Stillings, Lisa L.; Amacher, Michael C.; Ippolito, James A.; DeCrappeo, Nicole M.

2010-01-01

265

Impacts of Pacific Decadal Variability on Marine Ecosystems  

NASA Astrophysics Data System (ADS)

Over the past few decades a wealth of evidence has pointed to important connections between multi-decadal climate changes coherent with North Pacific ecosystem changes. The period from the late 1970's through the mid-1990's, for example, saw sustained high productivity for most Pacific salmon at the northern end of their range coinciding with sustained low productivity for Pacific salmon at the southern end of their range. It is now recognized that this "north-south inverse production pattern" for Pacific salmon played out over much of the 20th Century in response to Pacific climate changes: over multiple decades associated with the Pacific Decadal Oscillation, and from year-to-year associated with the El Nino Southern Oscillation. There is likewise abundant evidence for climate impacts on many other North Pacific marine species from the California Current north to the Bering Sea. In special cases, interdecadal ecosystem changes have been termed "regime shifts", wherein direct and indirect evidence points to large-scale ecosystem restructuring at both lower and upper trophic levels. The growing recognition of climate influences has undoubtedly aided our understanding of variations in Pacific marine ecosystems. In contrast, understanding and predicting ecosystem changes at the time-space scales important to fishery management decisions remains a major challenge.

Mantua, N. J.

2002-05-01

266

Nutrients and Water Relations in Mediterranean-Type Ecosystems1  

E-print Network

shrubs are believed to occur in California where the length of the soil drought is about 100 days or less-type Ecosystems, June 22 26. 1981 San Diego, California 2 Director, Systems Ecology Research Group, San Diego State University, San Diego, California 92109 Abstract: Mediterranean regions of the world

Standiford, Richard B.

267

Effects of livestock management on Southwestern riparian ecosystems  

E-print Network

practices such as river channelization, clearing for agriculture, livestock grazing, water impoundments on the ecosystems of western North America than development. Yet, the response of conservationists to the problem Baja California Norte, Baja California Sur, Chihuahua, Coahuila, Sonora, Arizona, California, Colorado

268

Freshwater Ecosystems  

NSDL National Science Digital Library

In this activity, learners create a freshwater ecosystem in a large plastic bottle. Learners cut and prepare bottles, then fill with water, aquatic plants, snails and fish. Learners observe their mini-ecosystem over time to see what changes--such as the color of the water, the water temperature, plant growth, and behavior and/or population of the snails or fish. The activity serves as a model for larger freshwater ecosystems such as ponds, lakes, rivers, streams, wetlands, reservoirs and groundwater.

2013-12-18

269

Coral Ecosystems  

NSDL National Science Digital Library

Why study coral ecosystems? Having survived millions of years, coral reefs are among the oldest and most diverse ecosystems on earth. Learning about coral ecosystems encompasses many of the 9-12 grade science curriculum standards. Life cycles of organisms, biological structure and function of organisms, and the behaviors and adaptations of organisms to their environment are all topics easily studied through a focus on coral reefs. All populations in this ecosystem are interdependent and part of a global food web. Healthy coral ecosystems are important to the humans, plants, fish, and other organisms that depend on them. However, the increasing impact of climate changes and human activities is endangering the very survival of these ecosystems. Pollution, habitat loss, invasive species, and diseases are all threats to the survival of coral ecosystems around the globe. Learning about them- "their fragility and value"- will help students understand what is needed to protect them. This SciGuide highlights outstanding NOAA resources, such as online tutorials and complete, hands-on, inquiry based lesson plans from the National Ocean Services. These resources address three areas. First, students can study the biology of the coral organism, learning about types of coral and where they are found. Next, resources focus on the populations, habitat, and dynamics of coral ecosystems. Finally, teachers and students, through online data sources and activities, learn about conservation of our coral ecosystems. Natural threats, human disturbances, and the benefits of coral protection focus students on the real world importance of science learning.

National Science Teachers Association (NSTA)

2006-06-01

270

Use of marine sanctuaries by far-ranging predators: commuting flights to the California Current System by breeding Hawaiian albatrosses  

Microsoft Academic Search

Quantifying the dispersion and habitats of far-ranging seabirds, turtles, and cetaceans is essential to assess whether zoning strategies can help protect upper- trophic marine predators. In this paper, we focus on Black-footed Albatross (Phoebastria nigripes) use of three US national marine sanctuaries off central California: Cordell Bank, Gulf of the Farallones, and Monterey Bay. We assessed the significance of these

K. D. HYRENBACH; C. KEIPER; S. G. ALLEN; D. G. AINLEY; D. J. ANDERSON

2006-01-01

271

Spatial analysis of plague in California: niche modeling predictions of the current distribution and potential response to climate change  

PubMed Central

Background Plague, caused by the bacterium Yersinia pestis, is a public and wildlife health concern in California and the western United States. This study explores the spatial characteristics of positive plague samples in California and tests Maxent, a machine-learning method that can be used to develop niche-based models from presence-only data, for mapping the potential distribution of plague foci. Maxent models were constructed using geocoded seroprevalence data from surveillance of California ground squirrels (Spermophilus beecheyi) as case points and Worldclim bioclimatic data as predictor variables, and compared and validated using area under the receiver operating curve (AUC) statistics. Additionally, model results were compared to locations of positive and negative coyote (Canis latrans) samples, in order to determine the correlation between Maxent model predictions and areas of plague risk as determined via wild carnivore surveillance. Results Models of plague activity in California ground squirrels, based on recent climate conditions, accurately identified case locations (AUC of 0.913 to 0.948) and were significantly correlated with coyote samples. The final models were used to identify potential plague risk areas based on an ensemble of six future climate scenarios. These models suggest that by 2050, climate conditions may reduce plague risk in the southern parts of California and increase risk along the northern coast and Sierras. Conclusion Because different modeling approaches can yield substantially different results, care should be taken when interpreting future model predictions. Nonetheless, niche modeling can be a useful tool for exploring and mapping the potential response of plague activity to climate change. The final models in this study were used to identify potential plague risk areas based on an ensemble of six future climate scenarios, which can help public managers decide where to allocate surveillance resources. In addition, Maxent model results were significantly correlated with coyote samples, indicating that carnivore surveillance programs will continue to be important for tracking the response of plague to future climate conditions. PMID:19558717

Holt, Ashley C; Salkeld, Daniel J; Fritz, Curtis L; Tucker, James R; Gong, Peng

2009-01-01

272

Ecosystem feedbacks to climate change in California: Development, testing, and analysis using a coupled regional atmosphere and land-surface model (WRF3-CLM3.5)  

SciTech Connect

A regional atmosphere model [Weather Research and Forecasting model version 3 (WRF3)] and a land surface model [Community Land Model, version 3.5 (CLM3.5)] were coupled to study the interactions between the atmosphere and possible future California land-cover changes. The impact was evaluated on California's climate of changes in natural vegetation under climate change and of intentional afforestation. The ability of WRF3 to simulate California's climate was assessed by comparing simulations by WRF3-CLM3.5 and WRF3-Noah to observations from 1982 to 1991. Using WRF3-CLM3.5, the authors performed six 13-yr experiments using historical and future large-scale climate boundary conditions from the Geophysical Fluid Dynamics Laboratory Climate Model version 2.1 (GFDL CM2.1). The land-cover scenarios included historical and future natural vegetation from the Mapped Atmosphere-Plant-Soil System-Century 1 (MC1) dynamic vegetation model, in addition to a future 8-million-ha California afforestation scenario. Natural vegetation changes alone caused summer daily-mean 2-m air temperature changes of -0.7 to +1 C in regions without persistent snow cover, depending on the location and the type of vegetation change. Vegetation temperature changes were much larger than the 2-m air temperature changes because of the finescale spatial heterogeneity of the imposed vegetation change. Up to 30% of the magnitude of the summer daily-mean 2-m air temperature increase and 70% of the magnitude of the 1600 local time (LT) vegetation temperature increase projected under future climate change were attributable to the climate-driven shift in land cover. The authors projected that afforestation could cause local 0.2-1.2 C reductions in summer daily-mean 2-m air temperature and 2.0-3.7 C reductions in 1600 LT vegetation temperature for snow-free regions, primarily because of increased evapotranspiration. Because some of these temperature changes are of comparable magnitude to those projected under climate change this century, projections of climate and vegetation change in this region need to consider these climate-vegetation interactions.

Subin, Z.M.; Riley, W.J.; Kueppers, L.M.; Jin, J.; Christianson, D.S.; Torn, M.S.

2010-11-01

273

Foraminiferal area density as a proxy for ocean acidification over the last 200 years in the California Current System  

NASA Astrophysics Data System (ADS)

Anthropogenic activities have resulted in an increase in atmospheric CO2 from 280 ppm to 400 ppm over the last 250 years. It is estimated that approximately one-third of this anthropogenically produced CO2 is sequestered in the global ocean, increasing the inventory of bicarbonate (HCO3-) and hydrogen ions (H+) and consuming carbonate (CO32-) as a result of carbonate buffering reactions. This increase in [H+] lowers seawater pH, the phenomenon known as ocean acidification (OA). Estimates indicate that mean seawater pH has already decreased by 0.1 pH units since 1750 and IPCC reports indicate it is likely that CO2 concentrations will reach 790 ppm by 2100 further reducing pH by 0.3 units. Marine calcifiers, such as foraminifera, utilize CO32- dissolved in seawater during calcification, a process that is highly sensitive to changes in pH due to the chemical reactions described above. The reduction in surface ocean carbonate ion concentration ([CO32-]) caused by OA has impaired calcification of planktonic foraminifera and other marine calcifiers. It has been proposed that planktonic foraminiferal shell weight or shell thickness is positively correlated with ambient [CO32-] and has been used as proxy to reconstruct past changes in the surface ocean carbonate system. An ideal location for the application of this proxy is the California Current System (CSS), an Eastern Boundary Upwelling System (EBUS), which is characterized as having naturally lower pH. Upwelling introduces CO2-enriched bottom waters to the surface ocean, intensifying the effects of increasing dissolved CO2 as a result of anthropogenic activities. Upwelling produces a wide range of surface water [CO32-] making the Santa Barbara Basin (SBB) an ideal site to carry out a foraminiferal shell weight calibration study. Area density (?A) is a new method for collecting size-normalized shell weights that will be used in this study. Species-specific calibrations have been derived for two symbiont-barren planktonic foraminifera, N. pachyderma (dextral) and G. bulloides. ?A measurements of these species collected from 35 months of sediment trap material are regressed with corresponding calcification depth-specific [CO32-]. Preliminary results show that ?A for both species demonstrate a positive linear relationship with ambient [CO32-]. Seasonal upwelling patterns are clearly recorded in ?A measurements with lower values occurring during periods of peak upwelling, which typically initiates in early spring. Preliminary observations suggest that distinguishing different morphotypes and ontogenic stages of the planktonic foraminifera used in this study could optimize the calibration equations. Final calibration equations will be applied to ?A measurements for a 200-year core record collected near the sediment trap mooring in the SBB. This reconstruction will quantify changes in [CO32-] as a result of OA since the onset of the industrial revolution, providing insights for future reduction in calcification efficiency of foraminifera as a result of OA and increasing carbon emissions.

Osborne, E.; Thunell, R.

2013-12-01

274

Effects of Recent Debris Flows on Stream Ecosystems and Food Webs in Small Watersheds in the Central Klamath Mountains, NW California  

NASA Astrophysics Data System (ADS)

Debris flows are common erosional processes in steep mountain areas throughout the world, but little is known about the long-term ecological effects of debris flows on stream ecosystems. Based on debris flow histories that were developed for each of ten tributary basins, we classified channels as having experienced recent (1997) or older (pre-1997) debris flows. Of the streams classified as older debris flow streams, three streams experienced debris flows during floods in 1964 or 1974, while two streams showed little or no evidence of debris flow activity in the 20th century. White alder (Alnus rhombifolia) was the dominant pioneer tree species in recent debris flow streams, forming localized dense patches of canopy cover. Maximum temperatures and daily temperature ranges were significantly higher in recent debris flow streams than in older debris flow streams. Debris flows resulted in a shift in food webs from allochthonous to autochthonous energy sources. Primary productivity, as measured by oxygen change during the day, was greater in recent debris flow streams, resulting in increased abundances of grazers such as the armored caddisfly Glossosoma spp. Detritivorous stoneflies were virtually absent in recent debris flow streams because of the lack of year-round, diverse sources of leaf litter. Rainbow trout (Oncorhynchus mykiss) were abundant in four of the recent debris flow streams. Poor recolonizers, such as the Pacific giant salamander (Dicamptodon tenebrosus), coastal tailed frog (Ascaphus truei), and signal crayfish (Pacifistacus leniusculus), were virtually absent in recent debris flow streams. Forest and watershed managers should consider the role of forest disturbances, such as road networks, on debris flow frequency and intensity, and the resulting ecological effects on stream ecosystems.

Cover, M. R.; de La Fuente, J.

2008-12-01

275

Carbon dioxide and terrestrial ecosystems  

Microsoft Academic Search

This book is a summary of the current research which addresses the effects of elevated carbon dioxide on terrestrial ecosystems and an identification of significant unresolved issues. Chapters address the carbon dioxide effects on trees and forests, unmanaged herbaceous ecosystems, and crops. Included are experimental studies, conceptual models, general mathematical models, dynamic simulation models.

G. W. Koch; H. A. Mooney

1996-01-01

276

Arctic Ecosystem  

NSDL National Science Digital Library

Despite seemingly inhospitable conditions, the Arctic environment has a vibrant and diverse ecosystem. Explore the life that thrives in this region in this interactive activity adapted from the Woods Hole Oceanographic Institution.

2008-01-17

277

Antarctic Ecosystem  

NSDL National Science Digital Library

In contrast with its largely lifeless interior, the Antarctic coastal marine environment supports a vibrant and diverse ecosystem. Explore the region's living bounty in this interactive activity adapted from the Woods Hole Oceanographic Institution.

WGBH Educational Foundation

2008-01-17

278

Ecosystem Journalism  

NSDL National Science Digital Library

Third-grade students display their understanding of life science concepts by creating an imaginative newspaper. This creative writing project engages students in researching, writing, and editing a newspaper based on a prairie ecosystem.

Amy Robertson

2005-11-01

279

Elementary Ecosystems  

NSDL National Science Digital Library

This lesson teaches students the basics of species interdependency within an ecosystem. Students describe the things animals need to survive and the ways in which animals depend on other animals and plants; perform a simulation to demonstrate the interdependencies within an ecosystem; look at pictures of endangered animals, and explain what they think might happen to other animals and plants if these animals became extinct; and draw pictures of animals in their natural habitats, and describe what these animals need to survive.

2001-01-01

280

Is restoring an ecosystem good for your health?  

PubMed

It is well known that the degradation of ecosystems can have serious impacts on human health. There is currently a knowledge gap on what impact restoring ecosystems has on human health. In restoring ecosystems there is a drive to restore the functionality of ecosystems rather than restoring ecosystems to 'pristine' condition. Even so, the complete restoration of all ecosystem functions is not necessarily possible. Given the uncertain trajectory of the ecosystem during the ecosystem restoration process the impact of the restoration on human health is also uncertain. Even with this uncertainty, the restoration of ecosystems for human health is still a necessity. PMID:25261817

Speldewinde, P C; Slaney, D; Weinstein, P

2015-01-01

281

California Workforce: California Faces a Skills Gap  

ERIC Educational Resources Information Center

California's education system is not keeping up with the changing demands of the state's economy--soon, California will face a shortage of skilled workers. Projections to 2025 suggest that the economy will continue to need more and more highly educated workers, but that the state will not be able to meet that demand. If current trends persist,…

Public Policy Institute of California, 2011

2011-01-01

282

Linking ecosystem and parasite Michel Loreau,1  

E-print Network

13 CHAPTER 1 Linking ecosystem and parasite ecology Michel Loreau,1 Jacques Roy,2 and David Tilman3 Parasites are rarely considered in ecosystem studies. The current interest in the relationship between biodiversity and ecosystem functioning, however, has stimulated the emergence of new synthetic approaches

Minnesota, University of

283

Phreatophytic Vegetation and Groundwater Fluctuations: A Review of Current Research and Application of Ecosystem Response Modeling with an Emphasis on Great Basin Vegetation  

Microsoft Academic Search

Although changes in depth to groundwater occur naturally, anthropogenic alterations may exacerbate these fluctuations and, thus, affect vegetation reliant on groundwater. These effects include changes in physiology, structure, and community dynamics, particularly in arid regions where groundwater can be an important water source for many plants. To properly manage ecosystems subject to changes in depth to groundwater, plant responses to

Elke Naumburg; Ricardo Mata-gonzalez; Rachael G. Hunter; Terry Mclendon; David W. Martin

2005-01-01

284

Connections Among the Spatial and Temporal Structures in Tidal Currents, Internal Bores, and Surficial Sediment Distributions Over the Shelf off Palos Verdes, California  

USGS Publications Warehouse

The topography of the Continental Shelf in the central portion of the Southern California Bight has rapid variations over relatively small spatial scales. The width of the shelf off the Palos Verdes peninsula, just northwest of Los Angeles, California, is only 1 to 3 km. About 7 km southeast of the peninsula, the shelf within San Pedro Bay widens to about 20 km. In 2000, the Los Angeles County Sanitation District began deploying a dense array of moorings in this complex region of the central Southern California Bight to monitor local circulation patterns. Moorings were deployed at 13 sites on the Palos Verdes shelf and within the northwestern portion of San Pedro Bay. At each site, a mooring supported a string of thermistors and an adjacent bottom platform housed an Acoustic Doppler Current Profiler. These instruments collected vertical profiles of current and temperature data continuously for one to two years. The variable bathymetry in the region causes rapid changes in the amplitudes and spatial structures of barotropic tidal currents, internal tidal currents, and in the associated nonlinear baroclinic currents that occur at approximate tidal frequencies. The largest barotropic tidal constituent is M2, the principal semidiurnal tide. The amplitude of this tidal current changes over fairly short along-shelf length scales. Tidal-current amplitudes are largest in the transition region between the two shelves; they increase from about 5 cm/s over the northern San Pedro shelf to nearly 10 cm/s on the southern portion of the Palos Verdes Shelf. Tidal-current amplitudes are then reduced to less than 2 cm/s over the very narrow section of the northern Palos Verdes shelf that lies just 6 km upcoast of the southern sites. Models suggest that the amplitude of the barotropic M2 tidal currents, which propagate toward the northwest primarily as a Kelvin wave, is adjusting to the short topographic length scales in the region. Semidiurnal sea-level oscillations are, as expected, independent of these topographic variations; they have a uniform amplitude and phase structure over the entire region. Because the cross-shelf angle of the seabed over most of the Palos Verdes shelf is 1 to 3 degrees, which is critical for the local generation and/or enhancement of nonlinear characteristics in semidiurnal internal tides, some internal tidal-current events have strong asymmetric current oscillations that are enhanced near the seabed. Near-bottom currents in these events are directed primarily offshore with amplitudes that exceed 30 cm/s. The spatial patterns in these energetic near-bottom currents have fairly short-length scales. They are largest over the inner shelf and in the transition region between the Palos Verdes and San Pedro shelves. This spatial pattern is similar to that found in the barotropic tidal currents. Because these baroclinic currents have an approximate tidal frequency, an asymmetric vertical structure, and a somewhat stable phase, they can produce a non-zero depth-mean flow for periods of a few months. These baroclinic currents can interact with the barotropic tidal current and cause an apparent increase (or decrease) in the estimated barotropic tidal-current amplitude. The apparent amplitude of the barotropic tidal current may change by 30 to 80 percent or more in a current record that is less than three months long. The currents and surficial sediments in this region are in dynamic equilibrium in that the spatial patterns in bottom stresses generated by near-bed currents from surface tides, internal tides, and internal bores partly control the spatial patterns in the local sediments. Coarser sediments are found in the regions with enhanced bottom stresses (that is, over the inner shelf and in the region between the Palos Verdes and San Pedro shelves). Finer sediments are found over the northwestern portion of the Palos Verdes shelf, where near-bottom currents are relatively weak. The nonlinear asymmetries in the i

Noble, Marlene A.; Rosenberger, Kurt J.; Xu, Jingping; Signell, Richard P.; Steele, Alex

2009-01-01

285

COMPARISON OF RECORDING CURRENT METERS USED FOR MEASURING VELOCITIES IN SHALLOW WATERS OF SAN FRANCISCO BAY, CALIFORNIA.  

USGS Publications Warehouse

The authors determine the feasibility of collecting reliable current-meter data in shallow water under natural conditions. The study involved field testing four types of recording current meters (different speed sensors) and comparing data recorded by the meters under different field conditions. Speeds recorded by the current meters at slack water and during maximum flows were compared during calm and windy conditions at various tide levels.

Gartner, Jeffrey W.; Oltmann, Richard N.

1985-01-01

286

Chemical speciation of sulfur in marine cloud droplets and particles: Analysis of individual particles from the marine boundary layer over the California current  

NASA Astrophysics Data System (ADS)

Detailed chemical speciation of the dry residue particles from individual cloud droplets and interstitial aerosol collected during the Marine Stratus Experiment (MASE) was performed using a combination of complementary microanalysis techniques. Techniques include computer controlled scanning electron microscopy with energy dispersed analysis of X rays (CCSEM/EDX), time-of-flight secondary ionization mass spectrometry (TOF-SIMS), and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Samples were collected at the ground site located in Point Reyes National Seashore, approximately 1 km from the coast. This manuscript focuses on the analysis of individual particles sampled from air masses that originated over the open ocean and then passed through the area of the California current located along the northern California coast. On the basis of composition, morphology, and chemical bonding information, two externally mixed, distinct classes of sulfur containing particles were identified: chemically modified (aged) sea salt particles and secondary formed sulfate particles. The results indicate substantial heterogeneous replacement of chloride by methanesulfonate (CH3SO3-) and non-sea-salt sulfate (nss-SO42-) in sea-salt particles with characteristic ratios of nss-S/Na > 0.10 and CH3SO3-/nss-SO42- > 0.6.

Hopkins, Rebecca J.; Desyaterik, Yury; Tivanski, Alexei V.; Zaveri, Rahul A.; Berkowitz, Carl M.; Tyliszczak, Tolek; Gilles, Mary K.; Laskin, Alexander

2008-02-01

287

Chemical Speciation of Sulfur in Marine Cloud Droplets and Particles: Analysis of Individual Particles from Marine Boundary Layer over the California Current  

SciTech Connect

Detailed chemical speciation of the dry residue particles from individual cloud droplets and interstitial aerosol collected during the Marine Stratus Experiment (MASE) was performed using a combination of complementary microanalysis techniques. Techniques include computer controlled scanning electron microscopy with energy dispersed analysis of X-rays (CCSEM/EDX), time-of-flight secondary ionization mass spectrometry (TOF-SIMS), and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Samples were collected at the ground site located in Point Reyes National Seashore, approximately 1 km from the coast. This manuscript focuses on the analysis of individual particles sampled from air masses that originated over the open ocean and then passed through the area of the California current located along the northern California coast. Based on composition, morphology, and chemical bonding information, two externally mixed, distinct classes of sulfur containing particles were identified: chemically modified (aged) sea salt particles and secondary formed sulfate particles. The results indicate substantial heterogeneous replacement of chloride by methanesulfonate (CH3SO3-) and non-sea salt sulfate (nss-SO42-) in sea-salt particles with characteristic ratios of nss-S/Na>0.10 and CH3SO3-/nss-SO42->0.6.

William R. Wiley Environmental Sciences Laboratory, Pacific Northwest National Laboratory; Gilles, Mary K; Hopkins, Rebecca J.; Desyaterik, Yury; Tivanski, Alexei V.; Zaveri, Rahul A.; Berkowitz, Carl M.; Tyliszczak, Tolek; Gilles, Mary K.; Laskin, Alexander

2008-03-12

288

An Overview of the Impacts of Pacific Decadal Climate Variability on Marine Ecosystems  

NASA Astrophysics Data System (ADS)

Over the past few decades a wealth of evidence has pointed to strong associations between multi-decadal climate changes and marine ecosystem changes in the Pacific. The period from the late 1970's through the mid-1990's, for example, saw sustained high productivity for most Pacific salmon at the northern end of their range coinciding with sustained low productivity for Pacific salmon at the southern end of their range. It is now recognized that this "north-south inverse production pattern" for Pacific salmon played out over much of the 20th Century in response to Pacific Decadal climate variations. There is abundant direct and indirect evidence for decadal scale climate impacts on many other Pacific marine species, including (among others) sardines and anchovies in the Humboldt and California Currents, and pollock and crab in the Bering Sea. In special cases, interdecadal ecosystem changes have been termed "ecosystem regime shifts", wherein evidence points to large-scale ecosystem restructuring at both lower and upper trophic levels. Understanding the mechanisms linking decadal variations in climate to ecosystems has proven to be a major challenge, and the lack of understanding poses a serious barrier to predicting ecosystem changes at the time-space scales important to resource managers and the fishing industry.

Mantua, N.

2006-12-01

289

Harmful to None: Why California Should Recognize Out-Of-State Same-Sex Marriages under Its Current Marital Choice of Law Rule  

E-print Network

of same-sex marriage, the Hawaii Supreme Court partiallySAME-SEX MARRIAGE IN AMERICA In May of 1993, the Hawaii Supreme Courtsame-sex marriage statutes have been passed in California Two California Supreme Court

Cavazos, Sandra

1998-01-01

290

Coastal Ecosystems  

NSDL National Science Digital Library

This United States Geological Survey (USGS) report by the Western Ecological Research Center (WERC) highlights Pacific Ocean coastal ecosystems. The website outlines WERC studies that are providing insight into how coastal ecosystems function. The role of sea otters in coastal environments, white abalone (snail) reintroduction, the effects of invasive plants and animals, urban activity, industrial and agricultural pollutants, San Francisco Bay reclamation, population growth, and migratory birds are all investigated in these studies. Fact sheets about certain areas of research are provided for further information.

291

The impact of accelerating land-use change on the N-Cycle of tropical aquatic ecosystems: Current conditions and projected changes  

Microsoft Academic Search

Published data and analyses from temperate and tropical aquatic systems are used to summarize knowledge about the potential impact of land-use alteration on the nitrogen biogeochemistry of tropical aquatic ecosystems, identify important patterns and recommend key needs for research. The tropical N-cycle is traced from pre-disturbance conditions through the phases of disturbance, highlighting major differences between tropical and temperate systems

J. A. Downing; M. McClain; R. Twilley; J. M. Melack; J. Elser; N. N. Rabalais; W. M. Lewis; R. E. Turner; J. Corredor; D. Soto; A. Yanez-Arancibia; J. A. Kopaska; R. W. Howarth

1999-01-01

292

STATE OF CALIFORNIA THE RESOURCES AGENCY ARNOLD SCHWARZENEGGER, Governor CALIFORNIA ENERGY COMMISSION  

E-print Network

STATE OF CALIFORNIA ­ THE RESOURCES AGENCY ARNOLD SCHWARZENEGGER, Governor CALIFORNIA ENERGY Manufacturers of Major Home Appliances Dear Appliance Manufacturer: California is participating in the State), and will be administered within the state by the California Energy Commission. California is currently developing its

293

Stable Isotope Analysis Challenges Wasp-Waist Food Web Assumptions in an Upwelling Pelagic Ecosystem  

PubMed Central

Eastern boundary currents are often described as ‘wasp-waist’ ecosystems in which one or few mid-level forage species support a high diversity of larger predators that are highly susceptible to fluctuations in prey biomass. The assumption of wasp-waist control has not been empirically tested in all such ecosystems. This study used stable isotope analysis to test the hypothesis of wasp-waist control in the southern California Current large marine ecosystem (CCLME). We analyzed prey and predator tissue for ?13C and ?15N and used Bayesian mixing models to provide estimates of CCLME trophic dynamics from 2007–2010. Our results show high omnivory, planktivory by some predators, and a higher degree of trophic connectivity than that suggested by the wasp-waist model. Based on this study period, wasp-waist models oversimplify trophic dynamics within the CCLME and potentially other upwelling, pelagic ecosystems. Higher trophic connectivity in the CCLME likely increases ecosystem stability and resilience to perturbations. PMID:22977729

Madigan, Daniel J.; Carlisle, Aaron B.; Dewar, Heidi; Snodgrass, Owyn E.; Litvin, Steven Y.; Micheli, Fiorenza; Block, Barbara A.

2012-01-01

294

Persistent organic pollutants in forage fish prey of rhinoceros auklets breeding in Puget Sound and the northern California Current.  

PubMed

Organochlorine contaminants in upper trophic-level consumers inhabiting Puget Sound are consistently higher than in those species inhabiting other west coast locations. We analyzed persistent organic pollutants (POPs) in the six most common fish prey of rhinoceros auklets breeding on Protection Island (Puget Sound), Tatoosh Island (WA coast), and Destruction Island (WA coast). Wet-weight concentrations of POPs ranged widely (PCBs: 1.6-25.0 ng/g; DDTs: 0.2-56.0 ng/g; PBDEs:ecosystem. PMID:25103902

Good, Thomas P; Pearson, Scott F; Hodum, Peter; Boyd, Daryle; Anulacion, Bernadita F; Ylitalo, Gina M

2014-09-15

295

Facilitating Next Generation Science Collaboration: Respecting and Mediating Vocabularies with Information Model Driven Semantics in Ecosystems Assessments.  

NASA Astrophysics Data System (ADS)

In Earth and space science, there is steady evolution away from isolated and single purpose data 'systems' toward systems of systems, data ecosystems, or data frameworks that provide access to highly heterogeneous data repositories. As a result, common informatics approaches are being sought for the development and implementation of newer architectures. One clear need is a repeatable method for modeling, implementing and evolving the information architectures. A newly funded U.S. initiative is developing and deploying integrated ecosystem assessment (IEA) capability for marine ecosystems using an information science and semantic technologies. The intention is to advance the capacity of an IEA to provide the foundation for synthesis and quantitative analysis of natural and socio-economic ecosystem information to support ecosystem-based management. The initiative is creating capacity to assess the impacts of changing climate on two large marine ecosystems: the northeast U.S. and the California Current. These assessments will be essential parts of the science-based decision-support tools used to develop adaptive management measures. Enhanced collaboration is required to achieve these goals: interaction and information sharing within and among diverse data providers, analysis tool developers and user groups that constitute the broader coastal and marine ecosystem science application community. This presentation outlines new component design approaches and sets of information model and semantic encodings for mediation.

Fox, P.; Maffei, A.

2012-04-01

296

Desert Ecosystems  

NSDL National Science Digital Library

The Desert Ecosystems site describes the geology and climate, plants and animals, and cultural history of the main U.S. desert regions including: the Mojave Desert, the Great Basin, and the Colorado/Sonoran desert. There are also descriptions and photos of water in the desert, coyotes, the desert tortoise, and the creosote bush.

297

Digital Ecosystems: Ecosystem-Oriented Architectures  

Microsoft Academic Search

We view Digital Ecosystems to be the digital counterparts of biological ecosystems. Here, we are concerned with the creation\\u000a of these Digital Ecosystems, exploiting the self-organising properties of biological ecosystems to evolve high-level software\\u000a applications. Therefore, we created the Digital Ecosystem, a novel optimisation technique inspired by biological ecosystems,\\u000a where the optimisation works at two levels: a first optimisation, migration

Gerard Briscoe; Suzanne Sadedin; Philippe De Wilde

2011-01-01

298

Tidal salt marsh sediment in California, USA: part 3. Current and historic toxicity potential of contaminants and their bioaccumulation.  

PubMed

To assess potential health risks to benthic organisms from exposure to toxic contaminants, sediment chemistry data from five salt marshes along the coast of California were compared with threshold effects levels (TELs) and probable effects levels (PELs). As an integrated estimate of toxicity potential of multiple contaminants, mean PEL quotients (mPELQs) were used to categorize sampling stations into three groups: high (>0.5), medium (0.1-0.5) and low (<0.1). In all sediments from Stege Marsh located in San Francisco Bay, at least one contaminant exceeded PELs by up to 18-fold and mPELQs were higher than 0.7. Mean PELQs in two core sediments from eastern Stege Marsh ranged from 0.7 to 2.1, indicating that benthic organisms in Stege Marsh may have been adversely affected for several decades. To investigate bioavailability and bioaccumulation of contaminants in sediments, longjaw mudsuckers (Gillichthys mirabilis) were transplanted to six Stege Marsh stations for 60 days. Body burdens of organic contaminants clearly showed that they were readily available for benthic organisms. Measured concentrations of organic contaminants in mudsuckers were similar to estimated levels computed using a theoretical bioaccumulation potential model. Levels of PCBs and arsenic in mudsuckers were higher than screening values set as guidelines for the protection of humans and levels of PCBs and DDTs were higher than criteria for wildlife. The results of this study indicate that the levels of contaminants in Stege Marsh sediments may not fully support the well-being of benthic organisms and also may provoke adverse effects on fish-eating animals and humans through trophic transfer. PMID:18316112

Hwang, Hyun-Min; Green, Peter G; Young, Thomas M

2008-05-01

299

The California Crucible  

Microsoft Academic Search

Demographic changes in California offer a preview of national trends in racial and ethnic population groups, with projections of near parity between White and non-White populations by 2050. Racial and ethnic relations in California also provide insights into the conflicts and challenges of a multiethnic, multiracial society developing in the United States. This paper critiques the current Black-White model of

Jewelle Taylor Gibbs

1999-01-01

300

Long-term, high-frequency current and temperature measurements along central California: Insights into upwelling/relaxation and internal waves on the inner shelf  

USGS Publications Warehouse

Thermistor chains and acoustic Doppler current profilers were deployed at the northern and southern ends of Monterey Bay to examine the thermal and hydrodynamic structure of the inner (h ??? 20 m) shelf of central California. These instruments sampled temperature and current velocity at 2-min intervals over a 13-month period from June 2000 to July 2001. Time series of these data, in conjunction with SST imagery and CODAR sea surface current maps, helped to establish the basic hydrography for Monterey Bay. Analysis of time series data revealed that depth integrated flow at both sites was shore parallel (northwest-southeast) with net flows out of the Bay (northwest). The current and temperature records were dominated by semi-diurnal and diurnal tidal signals that lagged the surface tides by 3 h on average. Over the course of an internal tidal cycle these flows were asymmetric, with the flow during the flooding internal tide to the southeast typically lasting only one-third as long as the flow to the northwest during the ebbing internal tide. The transitions from ebb to flood were rapid and bore-like in nature; they were also marked by rapid increases in temperature and high shear. During the spring and summer, when thermal stratification was high, we observed almost 2000 high-frequency (Tp ??? 4-20 min) internal waves in packets of 8-10 following the heads of these bore-like features. Previous studies along the West Coast of the US have concluded that warm water bores and high-frequency internal waves may play a significant role in the onshore transport of larvae.

Storlazzi, C.D.; McManus, M.A.; Figurski, J.D.

2003-01-01

301

Long-term, high-frequency current and temperature measurements along central California: insights into upwelling/relaxation and internal waves on the inner shelf  

NASA Astrophysics Data System (ADS)

Thermistor chains and acoustic Doppler current profilers were deployed at the northern and southern ends of Monterey Bay to examine the thermal and hydrodynamic structure of the inner ( h˜20 m) shelf of central California. These instruments sampled temperature and current velocity at 2-min intervals over a 13-month period from June 2000 to July 2001. Time series of these data, in conjunction with SST imagery and CODAR sea surface current maps, helped to establish the basic hydrography for Monterey Bay. Analysis of time series data revealed that depth integrated flow at both sites was shore parallel (northwest-southeast) with net flows out of the Bay (northwest). The current and temperature records were dominated by semi-diurnal and diurnal tidal signals that lagged the surface tides by 3 h on average. Over the course of an internal tidal cycle these flows were asymmetric, with the flow during the flooding internal tide to the southeast typically lasting only one-third as long as the flow to the northwest during the ebbing internal tide. The transitions from ebb to flood were rapid and bore-like in nature; they were also marked by rapid increases in temperature and high shear. During the spring and summer, when thermal stratification was high, we observed almost 2000 high-frequency ( Tp˜4-20 min) internal waves in packets of 8-10 following the heads of these bore-like features. Previous studies along the West Coast of the US have concluded that warm water bores and high-frequency internal waves may play a significant role in the onshore transport of larvae.

Storlazzi, C. D.; McManus, M. A.; Figurski, J. D.

2003-06-01

302

Field Surveys of Rare Plants on Santa Cruz Island, California, 2003-2006: Historical Records and Current Distributions  

USGS Publications Warehouse

Santa Cruz Island is the largest of the northern Channel Islands located off the coast of California. It is owned and managed as a conservation reserve by The Nature Conservancy and the Channel Islands National Park. The island is home to nine plant taxa listed in 1997 as threatened or endangered under the federal Endangered Species Act, because of declines related to nearly 150 years of ranching on the island. Feral livestock were removed from the island as a major conservation step, which was part of a program completed in early 2007 with the eradication of pigs and turkeys. For the first time in more than a century, the rare plants of Santa Cruz Island have a chance to recover in the wild. This study provides survey information and living plant materials needed for recovery management of the listed taxa. We developed a database containing information about historical collections of the nine taxa and used it to plan a survey strategy. Our objectives were to relocate as many of the previously known populations as possible, with emphasis on documenting sites not visited in several decades, sites that were poorly documented in the historical record, and sites spanning the range of environmental conditions inhabited by the taxa. From 2003 through 2006, we searched for and found 39 populations of the taxa, indicating that nearly 80 percent of the populations known earlier in the 1900s still existed. Most populations are small and isolated, occupying native-dominated habitat patches in a highly fragmented and invaded landscape; they are still at risk of declining through population losses. Most are not expanding beyond the edges of their habitat patches. However, most taxa appeared to have good seed production and a range of size classes in populations, indicating a good capacity for plant recruitment and population growth in these restricted sites. For these taxa, seed collection and outplanting might be a good strategy to increase numbers of populations for species recovery. Several taxa have particular problems evidenced by lack of fruit set, very small population sizes, or unstable habitats. We collected seeds of all but two taxa for seed banking, and live cuttings of two clonal shrubs for cultivation at the Santa Barbara Botanic Garden. The survey data, seeds and cuttings provide a baseline and a foundation for planning, conducting, and tracking recovery of the nine federally listed plant taxa of Santa Cruz Island.

McEachern, A. Kathryn; Chess, Katherine A.; Niessen, Ken

2010-01-01

303

California State Waters Map Series: offshore of San Gregorio, California  

USGS Publications Warehouse

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California's State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of San Gregorio map area is located in northern California, on the Pacific coast of the San Francisco Peninsula about 50 kilometers south of the Golden Gate. The map area lies offshore of the Santa Cruz Mountains, part of the northwest-trending Coast Ranges that run roughly parallel to the San Andreas Fault Zone. The Santa Cruz Mountains lie between the San Andreas Fault Zone and the San Gregorio Fault system. The nearest significant onshore cultural centers in the map area are San Gregorio and Pescadero, both unincorporated communities with populations well under 1,000. Both communities are situated inland of state beaches that share their names. No harbor facilities are within the Offshore of San Gregorio map area. The hilly coastal area is virtually undeveloped grazing land for sheep and cattle. The coastal geomorphology is controlled by late Pleistocene and Holocene slip in the San Gregorio Fault system. A westward bend in the San Andreas Fault Zone, southeast of the map area, coupled with right-lateral movement along the San Gregorio Fault system have caused regional folding and uplift. The coastal area consists of high coastal bluffs and vertical sea cliffs. Coastal promontories in the northern and southern parts of the map area are the result of right-lateral motion on strands of the San Gregorio Fault system. In the south, headlands near Pescadero Point have been uplifted by motion along the west strand of the San Gregorio Fault (also called the Frijoles Fault), which separates rocks of the Pigeon Point Formation south of the fault from rocks of the Purisima Formation north of the fault. The regional uplift in this map area has caused relatively shallow water depths within California's State Waters and, thus, little accommodation space for sediment accumulation. Sediment is observed offshore in the central part of the map area, in the shelter of the headlands north of the east strand of the San Gregorio Fault (also called the Coastways Fault) around Miramontes Point (about 5 km north of the map area) and also on the outer half of the California's State Waters shelf in the south where depths exceed 40 m. Sediment in the outer shelf of California's State Waters is rippled, indicating some mobility. The Offshore of San Gregorio map area lies within the cold-temperate biogeographic zone that is called either the "Oregonian province" or the "northern California ecoregion." This biogeographic province is maintained by the long-term stability of the southward-flowing California Current, an eastern limb of the North Pacific subtropical gyre that flows from Oregon to Baja California. At its midpoint off central California, the California Current transports subarctic surface (0–500 m deep) waters southward, about 150 to 1,300 km from shore. Seasonal northwesterly winds that are, in part, responsible for the California Current, generate coastal upwelling. The south end of the Oregonian province is at Point Conception (about 350 km south of the map area), although its associated phylogeographic group of marine fauna may extend beyond to the area offshore of Los Angeles in southern California. The ocean off of central California has experienced a warming over the last 50 years that is driving an ecosystem shift away from the productive subarctic r

Cochrane, Guy R.; Dartnell, Peter; Greene, H. Gary; Watt, Janet T.; Golden, Nadine E.; Endris, Charles A.; Phillips, Eleyne L.; Hartwell, Stephen R.; Johnson, Samuel Y.; Kvitek, Rikk G.; Erdey, Mercedes D.; Bretz, Carrie K.; Manson, Michael W.; Sliter, Ray W.; Ross, Stephanie L.; Dieter, Bryan E.; Chin, John L.; Cochran, Susan A.

2014-01-01

304

An Overview of Riparian Forests in California  

E-print Network

An Overview of Riparian Forests in California: Their Ecology and Conservation 1 2 Anne Sands and Greg Howe This paper is comprised of abstracts from presentations made at the Symposium on Riparian which will work together to establish protection for the endangered riparian ecosystems of California

305

Chaparral in Southern California1 Robert R. Tyrrel2  

E-print Network

, small, thick, and stiff in order to cope with drought periods. The common genera of Southern CaliforniaChaparral in Southern California1 Robert R. Tyrrel2 1Presented at the Symposium on Dynamics and Management of Mediterranean-type Ecosystems, June 22-26, 1981, San Diego, California. 2Forest Supervisor, San

Standiford, Richard B.

306

75 FR 11555 - Notice of Public Meeting: Northeast California Resource Advisory Council and Subcommittee  

Federal Register 2010, 2011, 2012, 2013, 2014

...California Resource Advisory Council and its Sage Steppe Ecosystem Subcommittee will meet as indicated below. DATES: The RAC Sage Steppe Ecosytem Subcommittee will meet...coordination for implementing projects under the Sage Steppe Ecosystem Restoration...

2010-03-11

307

Quantifying Water Flow within Aquatic Ecosystems Using Load Cell Sensors: A Profile of Currents Experienced by Coral Reef Organisms around Lizard Island, Great Barrier Reef, Australia  

PubMed Central

Current velocity in aquatic environments has major implications for the diversity, abundance and ecology of aquatic organisms, but quantifying these currents has proven difficult. This study utilises a simple and inexpensive instrument (<$150) to provide a detailed current velocity profile of the coral-reef system around Lizard Island (Great Barrier Reef, Australia) at a spatial and temporal scale relevant to the ecology of individual benthos and fish. The instrument uses load-cell sensors to provide a correlation between sensor output and ambient current velocity of 99%. Each instrument is able to continuously record current velocities to >500 cms?1 and wave frequency to >100 Hz over several weeks. Sensor data are registered and processed at 16 MHz and 10 bit resolution, with a measuring precision of 0.06±0.04%, and accuracy of 0.51±0.65% (mean ±S.D.). Each instrument is also pressure rated to 120 m and shear stresses ?20 kNm?2 allowing deployment in harsh environments. The instrument was deployed across 27 coral reef sites covering the crest (3 m), mid-slope (6 m) and deep-slope (9 m depth) of habitats directly exposed, oblique or sheltered from prevailing winds. Measurements demonstrate that currents over the reef slope and crest varies immensely depending on depth and exposure: Currents differ up to 9-fold within habitats only separated by 3 m depth and 15-fold between exposed, oblique and sheltered habitats. Comparisons to ambient weather conditions reveal that currents around Lizard Island are largely wind driven. Zero to 22.5 knot winds correspond directly to currents of 0 to >82 cms?1, while tidal currents rarely exceed 5.5 cms?1. Rather, current velocity increases exponentially as a function of wave height (0 to 1.6 m) and frequency (0.54 to 0.20 Hz), emphasizing the enormous effect of wind and waves on organisms in these shallow coral reef habitats. PMID:24421878

Johansen, Jacob L.

2014-01-01

308

Ecosystem Overfishing in the Ocean  

PubMed Central

Fisheries catches represent a net export of mass and energy that can no longer be used by trophic levels higher than those fished. Thus, exploitation implies a depletion of secondary production of higher trophic levels (here the production of mass and energy by herbivores and carnivores in the ecosystem) due to the removal of prey. The depletion of secondary production due to the export of biomass and energy through catches was recently formulated as a proxy for evaluating the ecosystem impacts of fishing–i.e., the level of ecosystem overfishing. Here we evaluate the historical and current risk of ecosystem overfishing at a global scale by quantifying the depletion of secondary production using the best available fisheries and ecological data (i.e., catch and primary production). Our results highlight an increasing trend in the number of unsustainable fisheries (i.e., an increase in the risk of ecosystem overfishing) from the 1950s to the 2000s, and illustrate the worldwide geographic expansion of overfishing. These results enable to assess when and where fishing became unsustainable at the ecosystem level. At present, total catch per capita from Large Marine Ecosystems is at least twice the value estimated to ensure fishing at moderate sustainable levels. PMID:19066624

Tudela, Sergi; Palomera, Isabel; Pranovi, Fabio

2008-01-01

309

Annual Report to the Bonneville Power Administration, Reporting Period: April 2008 - February 2009 [re: "Survival and Growth in the Columbia River Plume and north California Current"].  

SciTech Connect

We have made substantial progress toward our objectives outlined in our BPA supported proposal entitled 'Columbia River Basin Juvenile Salmonids: Survival and Growth in the Columbia River Plume and northern California Current' which we report on herein. During 2008, we were able to successfully conduct 3 mesoscale cruises. We also were able to conduct 7 biweekly predator cruises, along with substantial shore-based visual observations of seabirds. Detailed results of the mesoscale cruises are available in the Cruise Reports and summarized in the next section. We have taken a proactive approach to getting the results of our research to fisheries managers and the general public. We have begun to make annual predictions based on ocean conditions of the relative survival of juvenile coho and Chinook salmon well before they return as adults. This is based on both biological and physical indicators that we measure during our surveys or collect from outside data sources. Examples of our predictions for 2009 and 2010 are available on the following web site: http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm.

Northwest Fisheries Science Center, NOAA Fisheries; Cooperative Institute for Marine Resources Studies, Oregon State University; OGI School of Science & Engineering, Oregon Health Sciences University.

2009-07-17

310

Biodiversity regulates ecosystem predictability  

Microsoft Academic Search

Links between biodiversity and ecosystem function provide compelling reasons for conserving maximal numbers of species in ecosystems. Here we describe a previously unrecognized effect of biodiversity on ecosystem predictability, where predictability is inversely related to temporal and spatial variation in ecosystem properties. By manipulating biodiversity in aquatic microbial communities, we show that one process, ecosystem respiration, becomes more predictable as

Jill McGrady-Steed; Patricia M. Harris; Peter J. Morin

1997-01-01

311

Bedform Morphology Under Significant Wave-Tidal Current Interaction at the Mouth of a Major Tidal Inlet, San Francisco, California  

NASA Astrophysics Data System (ADS)

The mouth of San Francisco Bay is an extremely dynamic tidal inlet environment, where wave heights commonly exceed 5 m during the winter. During peak flow, tidal currents approach 3 m/s at the Golden Gate, which carries a tidal prism of 2 billion cubic meters. Flow structure varies markedly spatially and temporally due to the complex interaction of wind, waves and tides. The dominant patterns of this interaction are expressed in the bedform morphology of the tidal inlet, which in turn is an expression of the dominant sediment-transport pathways. Identifying pathways of sediment transport is essential information for coastal managers in this region who direct dredging operations and seek the most efficient means of mitigating erosion on adjacent Ocean Beach. A multibeam sonar survey was recently completed that mapped in high resolution, for the first time, the seafloor morphology at the mouth of San Francisco Bay. Highlights of the data set include one of the largest sand-wave fields on record (n= 40, max wavelength= 220 m, max amplitude= 5 m, max depth= 106 m) and an extremely diverse array of bedform morphologies, scales and orientations around the inlet mouth. Hydrodynamic and wave modeling suggest complex flow structures around the inlet mouth and offshore of adjacent Ocean Beach that are well correlated with observed bedform morphologies. The processes that control the morphology of the adjacent beach are intimately related to the processes that control sediment transport about the ebb tidal delta at the mouth of San Francisco Bay. The link between the ebb tidal delta and the adjacent beach is well represented by the bedform morphology.

Barnard, P. L.; Hanes, D. M.

2005-12-01

312

CALIFORNIA ENERGY COMMISSION California Energy Commission  

E-print Network

CALIFORNIA ENERGY COMMISSION California Energy Commission DOCKETED /3-I"b-P-l PETITION OF AMERICAN LUNG ASSOCIATION IN CALIFORNIA, ASIAN PACIFIC ENVIRONMENTAL NETWORK, BRIGHTLINE DEFENSE PROJECT, CALIFORNIA CENTER FOR SUSTAINABLE ENERGY, CALIFORNIA ENVIRONMENTAL JUSTICE ALLIANCE, CALIFORNIA SOLAR ENERGY

313

I Spy an Ecosystem  

NSDL National Science Digital Library

We hear the word ecosystems in the news and at school but just what are ecosystems? It turns out there are lots of ecosystems. You might even learn you have some inside you! Also in: Français | Español

Dr. Biology

314

Shrubs as ecosystem engineers in a coastal dune: influences on plant populations, communities and ecosystems  

E-print Network

Shrubs as ecosystem engineers in a coastal dune: influences on plant populations, communities the landscape? Location: Coastal hind-dune system, Bodega Head, northern California. Methods: In each of 4 years ­ Ericameria ericoides and the nitrogen-fixing Lupinus chamissonis ­ with those in adjacent open dunes. Results

Cushman, J. Hall

315

A perspective on modern pesticides, pelagic fish declines, and unknown ecological resilience in highly managed ecosystems  

USGS Publications Warehouse

Pesticides applied on land are commonly transported by runoff or spray drift to aquatic ecosystems, where they are potentially toxic to fishes and other nontarget organisms. Pesticides add to and interact with other stressors of ecosystem processes, including surface-water diversions, losses of spawning and rearing habitats, nonnative species, and harmful algal blooms. Assessing the cumulative effects of pesticides on species or ecological functions has been difficult for historical, legal, conceptual, and practical reasons. To explore these challenges, we examine current-use (modern) pesticides and their potential connections to the abundances of fishes in the San Francisco Estuary (California). Declines in delta smelt (Hypomesus transpacificus), Chinook salmon (Oncorhynchus tshawytscha), and other species have triggered mandatory and expensive management actions in the urbanizing estuary and agriculturally productive Central Valley. Our inferences are transferable to other situations in which toxics may drive changes in ecological status and trends.

Scholz, Nathaniel L.; Fleishman, Erica; Brown, Larry; Werner, Inge; Johnson, Michael L.; Brooks, Marjorie L.; Mitchelmore, Carys L.; Schlenk, Daniel

2012-01-01

316

Anchovy (Engraulis ringens) and sardine (Sardinops sagax) spatial dynamics and aggregation patterns in the Humboldt Current ecosystem, Peru, from 1983?2003  

Microsoft Academic Search

Three indexes of spatial aggregation are developed and used to examine the aggregation pattern of sardine (Sardinops sagax) and anchovy (Engraulis ringens )i n the Peruvian Humboldt Current System, determined from 36 acoustic surveys conducted from 1983 through 2003 by the Peruvian Marine Institute (IMARPE). Each index assesses a different aspect of aggregation: the concentration, the percent occupancy of space

MARIANO GUTIÉRREZ; GORDON SWARTZMAN; ARNAUD BERTRAND; SOPHIE BERTRAND

2007-01-01

317

California Missions  

NSDL National Science Digital Library

The California Museum of Photography at the University of California-Riverside, (last mentioned in the May 30, 2000 Scout Report for Social Sciences) is a site worth visiting again and again; there is always something new to look at in a variety of areas: photography history, California lifestyle and culture, fine art photography, and photo journalism. The California Missions show includes over 100 historic views of the 21 California Missions, some dated as early as 1895.

318

The Regional Ocean Modeling System (ROMS) 4-dimensional variational data assimilation systems . Part II - Performance and application to the California Current System  

NASA Astrophysics Data System (ADS)

The Regional Ocean Modeling System (ROMS) 4-dimensional variational (4D-Var) data assimilation systems have been systematically applied to the mesoscale circulation environment of the California Current to demonstrate the performance and practical utility of the various components of ROMS 4D-Var. In particular, we present a comparison of three approaches to 4D-Var, namely: the primal formulation of the incremental strong constraint approach; the dual formulation “physical-space statistical analysis system”; and the dual formulation indirect representer approach. In agreement with theoretical considerations all three approaches converge to the same ocean circulation estimate when using the same observations and prior information. However, the rate of convergence of the dual formulation was found to be inferior to that of the primal formulation. Other aspects of the 4D-Var performance that relate to the use of multiple outer-loops, preconditioning, and the weak constraint are also explored. A systematic evaluation of the impact of the various components of the 4D-Var control vector (i.e. the initial conditions, surface forcing and open boundary conditions) is also presented. It is shown that correcting for uncertainties in the model initial conditions exerts the largest influence on the ability of the model to fit the available observations. Various important diagnostics of 4D-Var are also examined, including estimates of the posterior error, the information content of the observation array, and innovation-based consistency checks on the prior error assumptions. Using these diagnostic tools, we find that more than 90% of the observations assimilated into the model provide redundant information. This is a symptom of the large percentage of satellite data that are used and to some extent the nature of the data processing employed. This is the second in a series of three papers describing the ROMS 4D-Var systems.

Moore, Andrew M.; Arango, Hernan G.; Broquet, Gregoire; Edwards, Chris; Veneziani, Milena; Powell, Brian; Foley, Dave; Doyle, James D.; Costa, Dan; Robinson, Patrick

2011-10-01

319

The ultrastructural indicators of aquatic ecosystem health  

Microsoft Academic Search

Analyses by transmission electron microscopy (TEM) of the smallest organisms in surface waters can be used to assess ecosystem health; the evidence for this statement is reviewed and recommendations are made for optimal use of TEM technology in providing such assessments. Those groups of small organisms currently being considered as indicators of ecosystem health (viruses, bacteria, autotrophic picoplankton, and autotrophic

Gary G. Leppard; Mohiuddin Munawar

1992-01-01

320

The Extent of Novel Ecosystems: Long in  

E-print Network

historical models to investigate how novel ecosystems have spread across the terrestrial biosphere of Maryland, USA Novel Ecosystems: Intervening in the New Ecological World Order, First Edition. Edited in the last 8000 years, and we also show their likely current distribution in both the terrestrial and marine

Ellis, Erle C.

321

PRESERVING BIODIVERSITY: SPECIES, ECOSYSTEMS, OR LANDSCAPES?  

Microsoft Academic Search

Efforts to preserve biological diversity must focus increasingly at the ecosystem level because of the immense number of species, the majority of which are currently unknown. An ecosystem approach is also the only way to conserve processes and habitats (such as forest canopies, belowground habitats, and hyporheic zones) that, with their constituent species, are poorly known. Continued concern with species

JERRY F. FRANKLIN

1993-01-01

322

Astronomical Ecosystems  

NASA Astrophysics Data System (ADS)

Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

Neuenschwander, D. E.; Finkenbinder, L. R.

2004-05-01

323

Columbia River Estuary Ecosystem Classification Ecosystem Complex  

USGS Publications Warehouse

Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these processes will aid in prioritization of restoration efforts. This hierarchical Columbia River Estuary Ecosystem Classification (henceforth "Classification") of the Columbia River estuary is a spatial database of the tidally-influenced reaches of the lower Columbia River, the tidally affected parts of its tributaries, and the landforms that make up their floodplains for the 230 kilometers between the Pacific Ocean and Bonneville Dam. This work is a collaborative effort between University of Washington School of Aquatic and Fishery Sciences (henceforth "UW"), U.S. Geological Survey (henceforth "USGS"), and the Lower Columbia Estuary Partnership (henceforth "EP"). Consideration of geomorphologic processes will improve the understanding of controlling physical factors that drive ecosystem evolution along the tidal Columbia River. The Classification is organized around six hierarchical levels, progressing from the coarsest, regional scale to the finest, localized scale: (1) Ecosystem Province; (2) Ecoregion; (3) Hydrogeomorphic Reach; (4) Ecosystem Complex; (5) Geomorphic Catena; and (6) Primary Cover Class. For Levels 4 and 5, we mapped landforms within the Holocene floodplain primarily by visual interpretation of Light Detection and Ranging (LiDAR) topography supplemented with aerial photographs, Natural Resources Conservation Service (NRCS) soils data, and historical maps. Mapped landforms are classified as to their current geomorphic function, the inferred process regime that formed them, and anthropogenic modification. Channels were classified primarily by a set of depth-based rules and geometric relationships. Classification Level 5 floodplain landforms ("geomorphic catenae") were further classified based on multivariate analysis of land-cover within the mapped landform area and attributed as "sub-catena". The extent of detailed mapping is the interpreted Holocene geologic floodplain of the tidal Columbia River and its tributaries to the estimated head of tide. The extent of this dataset also includes tributary valleys that are not mapped in detail. The upstream extents of tributary valleys are an estimation of the limit of Columbia River influence and are for use as containers in future analyses. The geologic floodplain is the geomorphic surface that is actively accumulating sediment through occasional overbank deposition. Most features within the geologic floodplain are considered to be formed during the recent (Holocene-epoch) climatic regime. There are bedrock and pre-Holocene sedimentary deposits included where they are surrounded by Holocene sediment accumulations or have been shaped by Holocene floods. In some places, Holocene landforms such as landslides, tributary fans, and coastal dunes are mapped that extend outside of the modern floodplain. This map is not a floodplain hazard map or delineation of actual flood boundaries. Although wetlands are included in the Classification, they are based on different criteria than jurisdictional wetlands. The extent of mapping may differ from the actual limit of tidal influence.

Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith Marcoe

2012-01-01

324

Internet Geography: Ecosystems  

NSDL National Science Digital Library

This site about ecosystems and biomes contains a map of different ecosystems, and provides rainfall statistics for each biome. There are sections on tropical rainforest, taiga (or boreal forest), savanna, desert, and tundra ecosystems. Each section describes the biome and its origins, where it is found, and how humans impact it. In some cases, sustainable development of the ecosystem is explained.

325

Ecosystem element cycling Introduction  

E-print Network

Ecosystem element cycling Introduction An ecosystem consists of all the biological organisms and the physical environments they occupy together within a defined area [1]. The actual boundaries of an ecosystem are generally defined by researchers studying the ecosystem, who are usually interested in understanding

Ickert-Bond, Steffi

326

Graduate studies Ecosystem Science  

E-print Network

Graduate studies in Ecosystem Science and Management Ph.D. M.S. M.Agr. or Natural Resources Development MNRD Department of Ecosystem Science and Management College of Agriculture and Life Sciences in one or more of four broad research areas: ecosystem science; ecosystem management; spatial

327

Biodiversity and ecosystem multifunctionality  

Microsoft Academic Search

Biodiversity loss can affect ecosystem functions and services. Individual ecosystem functions generally show a positive asymptotic relationship with increasing biodiversity, suggesting that some species are redundant. However, ecosystems are managed and conserved for multiple functions, which may require greater biodiversity. Here we present an analysis of published data from grassland biodiversity experiments, and show that ecosystem multifunctionality does require greater

Andy Hector; Robert Bagchi

2007-01-01

328

Biodiversity and ecosystem functioning: Effects of the loss  

E-print Network

LETTER Biodiversity and ecosystem functioning: Effects of the loss of salamander species richness that biodiversity loss can have serious consequences for ecosystem processes. Lars Gamfeldt1 Department of Marine of biodiversity on ecosystem functioning: A consensus of current knowledge. Ecol Monogr 75:3­35. 2. Cardinale BJ

Wake, David B.

329

Spatiotemporal variability and drivers of pCO2 and air-sea CO2 fluxes in the California Current System: an eddy-resolving modeling study  

NASA Astrophysics Data System (ADS)

We quantify the CO2 source/sink nature of the California Current System (CalCS) and determine the drivers and processes behind the mean and spatiotemporal variability of the partial pressure of CO2 (pCO2) in the surface ocean. To this end, we analyze eddy-resolving, climatological simulations of a coupled physical-biogeochemical oceanic model on the basis of the Regional Oceanic Modeling System (ROMS). In the annual mean, the entire CalCS within 800 km of the coast and from ∼33° N to 46° N is essentially neutral with regard to atmospheric CO2: the model simulates an integrated uptake flux of -0.9 ± 3.6 Tg C yr-1, corresponding to an average flux density of -0.05 ± 0.20 mol C m-2 yr-1. This near zero flux is a consequence of an almost complete regional compensation between (i) strong outgassing in the nearshore region (first 100 km) that brings waters with high concentrations of dissolved inorganic carbon (DIC) to the surface and (ii) and a weaker, but more widespread uptake flux in the offshore region due to an intense biological reduction of this DIC, driven by the nutrients that are upwelled together with the DIC. The air-sea CO2 fluxes vary substantially in time, both on seasonal and sub-seasonal timescales, largely driven by variations in surface ocean pCO2. Most of the variability in pCO2 is associated with the seasonal cycle, with the exception of the nearshore region, where sub-seasonal variations driven by mesoscale processes dominate. In the regions offshore of 100 km, changes in surface temperature are the main driver, while in the nearshore region, changes in surface temperature, as well as anomalies in DIC and alkalinity (Alk) owing to changes in circulation, biological productivity and air-sea CO2 fluxes dominate. The prevalence of eddy-driven variability in the nearshore 100 km leads to a complex spatiotemporal mosaic of surface ocean pCO2 and air-sea CO2 fluxes that require a substantial observational effort to determine the source/sink nature of this region reliably.

Turi, G.; Lachkar, Z.; Gruber, N.

2014-02-01

330

Sustaining the Landscape: A Method for Comparing Current and Desired Future Conditions of Forest Ecosystems in the North Cumberland Plateau and Mountains  

SciTech Connect

This project initiates an integrated-landscape conservation approach within the Northern Cumberlands Project Area in Tennessee and Kentucky. The mixed mesophytic forests within the Cumberland Plateau and Mountains are among the most diverse in North America; however, these forests have been impacted by and remain threatened from changes in land use across this landscape. The integrated-landscape conservation approach presented in this report outlines a sequence of six conservation steps. This report considers the first three of these steps in two, successive stages. Stage 1 compares desired future conditions (DFCs) and current prevailing conditions (CPCs) at the landscape-scale utilizing remote sensing imagery, remnant forests, and descriptions of historical forest types within the Cumberland Plateau. Subsequently, Stage 2 compares DFCs and CPCs for at-risk forest types identified in Stage 1 utilizing structural, compositional, or functional attributes from USFS Forest Inventory and Analysis data. Ecological indicators will be developed from each stage that express the gaps between these two realizations of the landscape. The results from these first three steps will directly contribute to the final three steps of the integrated-landscape conservation approach by providing guidance for the generation of new conservation strategies in the Northern Cumberland Plateau and Mountains.

Druckenbrod, D.L.

2004-12-22

331

Pacific Island Ecosystems Research Center  

NSDL National Science Digital Library

The Pacific Island Ecosystems Research Center (PIERC) is part of the Biological Division of the United States Geological Survey (USGS). The mission of PIERC is to provide the scientific understanding and technologies needed to support the sound management and conservation of our Nation's biological resources occurring within the cultural, sociological, and political contexts of the State of Hawaii. The geographical isolation of the Hawaiian Islands has resulted in the evolution of a highly endemic biota, while human colonization has severely impacted native plant and animal populations. The PIERC website provides information and research studies about the Hawaiian Islands ecosystem, as well as staff projects that are currently in progress. Topics include birds, mammals, ecosystem diversity, genetics, wildlife health, plant ecology, and marine biology. There is an education section with outdoor activities, online activities, and a coloring book. Links are provided for further information.

332

Terrestrial ecosystems and climatic change  

SciTech Connect

The structure and function of terrestrial ecosystems depend on climate, and in turn, ecosystems influence atmospheric composition and climate. A comprehensive, global model of terrestrial ecosystem dynamics is needed. A hierarchical approach appears advisable given currently available concepts, data, and formalisms. The organization of models can be based on the temporal scales involved. A rapidly responding model describes the processes associated with photosynthesis, including carbon, moisture, and heat exchange with the atmosphere. An intermediate model handles subannual variations that are closely associated with allocation and seasonal changes in productivity and decomposition. A slow response model describes plant growth and succession with associated element cycling over decades and centuries. These three levels of terrestrial models are linked through common specifications of environmental conditions and constrain each other. 58 refs.

Emanuel, W.R. (Oak Ridge National Lab., TN (USA)); Schimel, D.S. (Colorado State Univ., Fort Collins, CO (USA). Natural Resources Ecology Lab.)

1990-01-01

333

Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon - April 2009  

EPA Science Inventory

Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

334

Measuring the contribution of benthic ecosystem engineering species to the ecosystem services of an estuary: A case study of burrowing shrimps in Yaquina Estuary, Oregon  

EPA Science Inventory

Burrowing shrimps are regarded as ecosystem engineering species in many coastal ecosystems worldwide, including numerous estuaries of the west coast of North America (Baja California to British Columbia). In estuaries of the U.S. Pacific Northwest, two species of large burrowing...

335

Using Seabird Habitat Modeling to Inform Marine Spatial Planning in Central California’s National Marine Sanctuaries  

PubMed Central

Understanding seabird habitat preferences is critical to future wildlife conservation and threat mitigation in California. The objective of this study was to investigate drivers of seabird habitat selection within the Gulf of the Farallones and Cordell Bank National Marine Sanctuaries to identify areas for targeted conservation planning. We used seabird abundance data collected by the Applied California Current Ecosystem Studies Program (ACCESS) from 2004–2011. We used zero-inflated negative binomial regression to model species abundance and distribution as a function of near surface ocean water properties, distances to geographic features and oceanographic climate indices to identify patterns in foraging habitat selection. We evaluated seasonal, inter-annual and species-specific variability of at-sea distributions for the five most abundant seabirds nesting on the Farallon Islands: western gull (Larus occidentalis), common murre (Uria aalge), Cassin’s auklet (Ptychorampus aleuticus), rhinoceros auklet (Cerorhinca monocerata) and Brandt’s cormorant (Phalacrocorax penicillatus). The waters in the vicinity of Cordell Bank and the continental shelf east of the Farallon Islands emerged as persistent and highly selected foraging areas across all species. Further, we conducted a spatial prioritization exercise to optimize seabird conservation areas with and without considering impacts of current human activities. We explored three conservation scenarios where 10, 30 and 50 percent of highly selected, species-specific foraging areas would be conserved. We compared and contrasted results in relation to existing marine protected areas (MPAs) and the future alternative energy footprint identified by the California Ocean Uses Atlas. Our results show that the majority of highly selected seabird habitat lies outside of state MPAs where threats from shipping, oil spills, and offshore energy development remain. This analysis accentuates the need for innovative marine spatial planning efforts and provides a foundation on which to build more comprehensive zoning and management in California’s National Marine Sanctuaries. PMID:23967206

McGowan, Jennifer; Hines, Ellen; Elliott, Meredith; Howar, Julie; Dransfield, Andrea; Nur, Nadav; Jahncke, Jaime

2013-01-01

336

Ecosystem health: I. Measuring ecosystem health  

NASA Astrophysics Data System (ADS)

Ecosystem analysis has been advanced by an improved understanding of how ecosystems are structured and how they function. Ecology has advanced from an emphasis on natural history to consideration of energetics, the relationships and connections between species, hierarchies, and systems theory. Still, we consider ecosystems as entities with a distinctive character and individual characteristics. Ecosystem maintenance and preservation form the objective of impact analysis, hazard evaluation, and other management or regulation activities. In this article we explore an approach to ecosystem analysis which identifies and quantifies factors which define the condition or state of an ecosystem in terms of health criteria. We relate ecosystem health to human/nonhuman animal health and explore the difficulties of defining ecosystem health and suggest criteria which provide a functional definition of state and condition. We suggest that, as has been found in human/nonhuman animal health studies, disease states can be recognized before disease is of clinical magnitude. Example disease states for ecosystems are functionally defined and discussed, together with test systems for their early detection.

Schaeffer, David J.; Herricks, Edwin E.; Kerster, Harold W.

1988-07-01

337

Coral Reef Ecosystems: Ecosystems in Crisis  

NSDL National Science Digital Library

This Science Object is the fourth of four Science Objects in the Coral Reef Ecosystems SciPack. It explores the natural and human causes of ecosystem stress. Human beings live near coral ecosystems and use them in a variety of ways. Increasing amounts of stress is brought on these ecosystems as humans continue to modify the surrounding environment as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening the stability and overall health of many coral reefs. Human activities may also exacerbate the impact of natural disturbances on coral reefs or compromise the ability of the reef to recover from events such as hurricanes, tsunamis, or disease. Learning Outcomes:? Describe ways in which human activities directly impact coral reef ecosystems (resource and recreational uses).? Describe ways in which human activities indirectly impact coral reef ecosystems (by changing the physical conditions, pollution, changes in the water chemistry, etc.).? Explain how human activity may decrease the reefs ability to recover from natural occurrences. ? Explain the effects of increased predation or disease on a reef ecosystem.? Describe the effect of habitat loss on the reef ecosystem.? Describe the effects of weather and climate change on a healthy and weakened reef ecosystem.

National Science Teachers Association (NSTA)

2007-03-28

338

Impacts of climate change on coastal benthic ecosystems: assessing the current risk of mortality outbreaks associated with thermal stress in NW Mediterranean coastal areas  

NASA Astrophysics Data System (ADS)

In the framework of climate change, the increase in ocean heat wave frequency is expected to impact marine life. Large-scale positive temperature anomalies already occurred in the northwestern Mediterranean Sea in 1999, 2003 and 2006. These anomalies were associated with mass mortality events of macrobenthic species in coastal areas (0-40 m in depth). The anomalies were particularly severe in 1999 and 2003 when thousands of kilometres of coasts and about 30 species were affected. The aim of this study was to develop a methodology to assess the current risk of mass mortality associated with temperature increase along NW Mediterranean continental coasts. A 3D regional ocean model was used to obtain the temperature conditions for the period 2001-2010, for which the model outputs were validated by comparing them with in situ observations in affected areas. The model was globally satisfactory, although extremes were underestimated and required correction. Combined with information on the thermo-tolerance of a key species (the red gorgonian P. clavata) as well as its spatial distribution, the modelled temperature conditions were then used to assess the risk of mass mortality associated with thermal stress for the first time. Most of the known areas of observed mass mortality were found using the model, although the degree of risk in certain areas was underestimated. Using climatic IPCC scenarios, the methodology could be applied to explore the impacts of expected climate change in the NW Mediterranean. This is a key issue for the development of sound management and conservation plans to protect Mediterranean marine biodiversity in the face of climate change.

Pairaud, Ivane Lilian; Bensoussan, Nathaniel; Garreau, Pierre; Faure, Vincent; Garrabou, Joaquim

2014-01-01

339

California Fires  

Atmospheric Science Data Center

article title:  Southern California Fires     View Larger ... than 250,000 people. These two images show the Southern California coast from Los Angeles to San Diego from two of the nine cameras on ... date:  Oct 21, 2007 Images:  California Fires location:  United States ...

2014-05-15

340

California Fires  

Atmospheric Science Data Center

article title:  Smoke Blankets Northern California     View Larger Image ... strikes sparked more than a thousand fires in northern California. This image was captured by the Multi-angle Imaging ... June 27, 2008 - Smoke from fires in northern California. project:  MISR category:  gallery ...

2014-05-15

341

California Coast  

Atmospheric Science Data Center

article title:  Southern California     View Larger Image ... Imaging SpectroRadiometer (MISR) images of Southern California were acquired on March 14, 2000 during Terra orbit 1273. North is at ... available at JPL March 14, 2000 - Southern California with the Mojave Desert and surrounding area. project:  ...

2014-05-15

342

Pelagic amphipod assemblage associated with subarctic water off the West Coast of the Baja California peninsula  

NASA Astrophysics Data System (ADS)

The California Current system is a large marine ecosystem with transition gradients between subarctic and tropical biomes containing diverse habitats. Biogeographic species groups must be carefully analyzed in order to detect tendencies shifting the ecosystem toward a more temperate or tropical state. Species composition of hyperiid amphipods was analyzed in July 2002 for evidence of subarctic water intrusion and for signals of the El Niño event developing in the equatorial Pacific. Multivariate analysis showed a dominance of “transition zone” species typical of the California Current. The main evidence of subarctic water intrusion was the extended distribution of Themisto pacifica, which reached as far south as 27°N, with particularly high abundances at 30-32°N. The intrusion of subarctic water took place despite evidence that an El Niño event was in progress. The zonal advection due to El Niño intersected the equatorward flow of the subarctic intrusion and probably produced a large cyclonic eddy off Baja California. This eddy maintained a limited El Niño influence at a few offshore stations near its southern boundary. The main environmental variables influencing the amphipod assemblage structure were water temperature and the abundance of salps. T. pacifica, a species with cool water affinity, was more sensitive to temperature, whereas subtropical species, such as Vibilia armata, were strongly correlated with the availability of salps.

Lavaniegos, Bertha E.

2014-04-01

343

Ecotoxicology of tropical marine ecosystems  

SciTech Connect

The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.

Peters, E.C. [Tetra Tech, Inc., Fairfax, VA (United States); Gassman, N.J.; Firman, J.C. [Univ. of Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Richmond, R.H. [Univ. of Guam, Mangilao (Guam). Marine Lab.; Power, E.A. [EVS Environment Consultants, Ltd., North Vancouver, British Columbia (Canada)

1997-01-01

344

RESEARCH TOPICS: Tree Guidelines for California Communities, Benefit-Cost Analyses, Energy and Carbon Dioxide Reduction through Urban Forestry, Air Quality and Parking Lot Shade, Urban Watershed Protection, Urban Forest Inventory and Monitoring, Green Infrastructure, Sustainable Urban Ecosystems  

Microsoft Academic Search

In California, repairing sidewalk damage associated with tree roots exceeds $62 million annuall this study, three types of root barriers were installed and evaluated to determine whether 1) inte (12 in.) of soil. The three barriers tested included 1) a modified production container, partially le intended to prevent circling roots and 3) a commercial product with vertical ribs spaced 12.5

Root Barrier; Extension Pau

345

Financing Postsecondary Education in California.  

ERIC Educational Resources Information Center

This document presents an overview of the financial aspects of postsecondary educational institutions in California and suggests some recommendations for the alleviation of financial problems. The study consisted of extensive research of the current literature on financing, gathering key data on the California system, reviewing the pertinent…

California State Legislature, Sacramento. Joint Committee on the Master Plan for Higher Education.

346

CALIFORNIA ENERGY CALIFORNIA'S STATE ENERGY  

E-print Network

CALIFORNIA ENERGY COMMISSION CALIFORNIA'S STATE ENERGY EFFICIENT APPLIANCE REBATE PROGRAM INITIAL November 2009 CEC-400-2009-026-CMD Arnold Schwarzenegger, Governor #12;#12;CALIFORNIA ENERGY COMMISSION Program Manager Paula David Supervisor Appliance and Process Energy Office Valerie T. Hall Deputy Director

347

Is Net Ecosystem Production Equal to Ecosystem Carbon Accumulation?  

E-print Network

COMMENTARY Is Net Ecosystem Production Equal to Ecosystem Carbon Accumulation? Gary M. Lovett ABSTRACT Net ecosystem production (NEP), defined as the difference between gross primary production: net ecosystem production; carbon accumulation; net primary production; gross pri- mary production

Berkowitz, Alan R.

348

Photodegradation Pathways in Arid Ecosystems  

NASA Astrophysics Data System (ADS)

Recent interest in improving our understanding of decomposition patterns in arid and semi-arid ecosystems and under potentially drier future conditions has led to a flurry of research related to abiotic degradation processes. Oxidation of organic matter by solar radiation (photodegradation) is one abiotic degradation process that contributes significantly to litter decomposition rates. Our meta-analysis results show that increasing solar radiation exposure corresponds to an average increase of 23% in litter mass loss rate with large variation among studies associated primarily with environmental and litter chemistry characteristics. Laboratory studies demonstrate that photodegradation results in CO2 emissions. Indirect estimates suggest that photodegradation could account for as much as 60% of ecosystem CO2 emissions from dry ecosystems, but these CO2 fluxes have not been measured in intact ecosystems. The current data suggest that photodegradation is important, not only for understanding decomposition patterns, but also for modeling organic matter turnover and ecosystem C cycling. However, the mechanisms by which photodegradation operates, along with their environmental and litter chemistry controls, are still poorly understood. Photodegradation can directly influence decomposition rates and ecosystem CO2 flux via photochemical mineralization. It can also indirectly influence biotic decomposition rates by facilitating microbial degradation through breakdown of more recalcitrant compounds into simpler substrates or by suppressing microbial activity directly. All of these pathways influence the decomposition process, but the relative importance of each is uncertain. Furthermore, a specific suite of controls regulates each of these pathways (e.g., environmental conditions such as temperature and relative humidity; physical environment such as canopy architecture and contact with soil; and litter chemistry characteristics such as lignin and cellulose content), and these controls have not yet been identified or quantified. To advance our understanding of photodegradation and its role in decomposition and in ecosystem C cycling, we must characterize its mechanisms and their associated controls and incorporate this understanding into biogeochemical models. Our objective is to summarize the current state of understanding of photodegradation and discuss some paths forward to address remaining critical gaps in knowledge about its mechanisms and influence on ecosystem C balance.

King, J. Y.; Lin, Y.; Adair, E. C.; Brandt, L.; Carbone, M. S.

2013-12-01

349

ECOSYSTEM GROWTH AND DEVELOPMENT  

EPA Science Inventory

Thermodynamically, ecosystem growth and development is the process by which energy throughflow and stored biomass increase. Several proposed hypotheses describe the natural tendencies that occur as an ecosystem matures, and here, we consider five: minimum entropy production, maxi...

350

California’s Energy Future: Transportation Energy Use in California  

E-print Network

Future Full Committee . 51 Appendix D: California Council on Science andFuture - Powering California with Nuclear Energy. California Council on Science andFuture - The View to 2050, Summary Report. California Council on Science and

Yang, Christopher; Ogden, Joan M; Hwang, Roland; Sperling, Daniel

2011-01-01

351

Review of current Southern California edison load management programs and proposal for a new market-driven, mass-market, demand-response program  

SciTech Connect

Utility load management programs, including direct load control and interruptible load programs, constitute a large installed base of controllable loads that are employed by utilities as system reliability resources. In response to energy supply shortfalls expected during the summer of 2001, the California Public Utilities Commission in spring 2001 authorized new utility load management programs as well as revisions to existing programs. This report provides an independent review of the designs of these new programs for a large utility (Southern California Edison) and suggests possible improvements to enhance the price responsiveness of the customer actions influenced by these programs. The report also proposes a new program to elicit a mass-market demand response to utility price signals.

Weller, G.H.

2002-01-01

352

Baltic Ecosystem Adaptive Management  

E-print Network

1 Baltic Ecosystem Adaptive Management Research for sustainable management of the Baltic Sea #12;2 Baltic Ecosystem Adaptive Management, BEAM, is an interdisciplinary research program on ecosystem-based management of the Baltic Sea environment. The program gathers researchers from three Faculties and ten

353

Biodiversity regulates ecosystem predictability  

Microsoft Academic Search

1-6 . Here we describe a previously unrecognized effect of biodiversity on ecosystem predictability, where predictability is inversely related to temporal and spatial variation in ecosystem properties. By manipulating biodiversity in aquatic microbial communities, we show that one process, ecosystem respiration, becomes more predictable as biodiversity increases. Analysis of similar patterns extracted from other studies 2,3,6 indicates that biodiversity also

Patricia M. Harris; Peter J. Morin

1997-01-01

354

Greater Everglades Ecosystem Restoration  

E-print Network

Greater Everglades Ecosystem Restoration (G.E.E.R.) Science Conference 'HILQLQJ6XFFHVV Naples Beach a Committee of the South Florida Ecosystem Restoration Task Force and Working Group #12;Greater Everglades Ecosystem Restoration (G.E.E.R.) Science Conference Page ii #12;December 11-15, 2000 z Naples, Florida Page

Watson, Craig A.

355

Ecosystem Health: Energy Indicators.  

EPA Science Inventory

Just as for human beings health is a concept that applies to the condition of the whole organism, the health of an ecosystem refers to the condition of the ecosystem as a whole. For this reason, the study and characterization of ecosystems is fundamental to establishing accurate ...

356

Fish communities of the Sacramento River Basin: Implications for conservation of native fishes in the Central Valley, California  

USGS Publications Warehouse

The associations of resident fish communities with environmental variables and stream condition were evaluated at representative sites within the Sacramento River Basin, California between 1996 and 1998 using multivariate ordination techniques and by calculating six fish community metrics. In addition, the results of the current study were compared with recent studies in the San Joaquin River drainage to provide a wider perspective of the condition of resident fish communities in the Central Valley of California as a whole. Within the Sacramento drainage, species distributions were correlated with elevational and substrate size gradients; however, the elevation of a sampling site was correlated with a suite of water-quality and habitat variables that are indicative of land use effects on physiochemical stream parameters. Four fish community metrics - percentage of native fish, percentage of intolerant fish, number of tolerant species, and percentage of fish with external anomalies - were responsive to environmental quality. Comparisons between the current study and recent studies in the San Joaquin River drainage suggested that differences in water-management practices may have significant effects on native species fish community structure. Additionally, the results of the current study suggest that index of biotic integrity-type indices can be developed for the Sacramento River Basin and possibly the entire Central Valley, California. The protection of native fish communities in the Central Valley and other arid environments continues to be a conflict between human needs for water resources and the requirements of aquatic ecosystems; preservation of these ecosystems will require innovative management strategies.

May, J.T.; Brown, L.R.

2002-01-01

357

Jampots: a Mashup System towards an E-Learning Ecosystem Bo Dong1, 2  

E-print Network

Jampots: a Mashup System towards an E-Learning Ecosystem Bo Dong1, 2 , Qinghua Zheng1, 2 , Lingzhi believed that an E-Learning ecosystem is the next generation E-Learning. Nowadays, the current trend of Web-Learning ecosystem. A mashup approach to an E-Learning ecosystem enhances the flourish and sustainability of E

Li, Haifei

358

California's Energy Policy: Conservation Works  

E-print Network

Conservation is the foundation of California's energy policy and the largest single source of the state's 'new energy supply'. Our goal is to use economic market forces and government programs to direct energy Investments away from our current...

Greene, D.

1982-01-01

359

Climate change adaptation potential for water in California  

NASA Astrophysics Data System (ADS)

California has an extensive, diverse, and highly interconnected water management system which serves a wide variety of purposes. Climatic change can have many effects on this system and there are many means to manage California's water systems with climatic change. Many studies of climate change in California support several conclusions that will be the focus of the talk. But more work is needed. Climatic change's effects on California's water system will coincide with significant population growth, economic change, technology development, and continuing evolution of water management for these and other reasons. California's large and highly-interconnected water infrastructure system provides many options for responding to climatic and other changes, and its decentralized water management system, while noisy, can provide a more responsive and thorough means of responding to climatic change. Large amounts of surface and groundwater storage significantly dampen the water supply effects of a seasonal shift in runoff. While a seasonal shift in runoff is inconvenient and adds costs for water supply, it is probably not the most vulnerable to climate warming. The water supply system is more vulnerable to long- term reductions in streamflow or persistent droughts, drier forms of climate change. The current water conveyance system is also highly vulnerable to sea level rise in the Sacramento-San Joaquin Delta. The flood management system is less well studied for climate change, but appears to be far more vulnerable to climate warming, especially wetter forms of climate warming. Revising reservoir flood operations manuals is like to be needed, along with changes to downstream infrastructure and land use. The ecosystem is probably the most vulnerable major water use to climatic change. Warmer marine and inland water temperatures combined with seasonal shifts and continued loss of habitat will increase challenges to native species, and in some cases these challenges are likely to be overwhelming.

Lund, J. R.

2008-12-01

360

Evaluation of Transportation Practices in the California Cut Flower Industry  

E-print Network

Page | 1 Evaluation of Transportation Practices in the California Cut Flower Industry Christine, California's share of the national cut flower market has decreased from 64 percent to 20 percent. California the California cut flower industry's current transportation practices and investigates the feasibility and cost

Dessouky, Maged

361

Ecosystem services in urban areas  

Microsoft Academic Search

Humanity is increasingly urban, but continues to depend on Nature for its survival. Cities are dependent on the ecosystems beyond the city limits, but also benefit from internal urban ecosystems. The aim of this paper is to analyze the ecosystem services generated by ecosystems within the urban area. ‘Ecosystem services’ refers to the benefits human populations derive from ecosystems. Seven

Per Bolund; Sven Hunhammar

1999-01-01

362

Environments and Ecosystems  

NSDL National Science Digital Library

Students explore the biosphere and its associated environments and ecosystems in the context of creating a model ecosystem, learning along the way about the animals and resources. Students investigate different types of ecosystems, learn new vocabulary, and consider why a solid understanding of one's environment and the interdependence of an ecosystem can inform the choices we make and the way we engineer our communities. This lesson is part of a series of six lessons in which students use their growing understanding of various environments and the engineering design process, to design and create their own model biodome ecosystems.

2014-09-18

363

Effects of ozone, nitrogen deposition, and other stressors on montane ecosystems in the Sierra Nevada  

Microsoft Academic Search

The greatest air pollution impacts in forests of California are the physiological disturbances imposed on trees as a result of the combined effects of excess N and phytotoxic ozone exposure (Takemoto et al., 2001). In highly-polluted stands in the San Bernardino Mountains in southern California, fine root biomass is greatly reduced and C cycling within the tree and within the ecosystem

Brent K Takemoto

2003-01-01

364

Climate change. Six centuries of variability and extremes in a coupled marine-terrestrial ecosystem.  

PubMed

Reported trends in the mean and variability of coastal upwelling in eastern boundary currents have raised concerns about the future of these highly productive and biodiverse marine ecosystems. However, the instrumental records on which these estimates are based are insufficiently long to determine whether such trends exceed preindustrial limits. In the California Current, a 576-year reconstruction of climate variables associated with winter upwelling indicates that variability increased over the latter 20th century to levels equaled only twice during the past 600 years. This modern trend in variance may be unique, because it appears to be driven by an unprecedented succession of extreme, downwelling-favorable, winter climate conditions that profoundly reduce productivity for marine predators of commercial and conservation interest. PMID:25237100

Black, Bryan A; Sydeman, William J; Frank, David C; Griffin, Daniel; Stahle, David W; García-Reyes, Marisol; Rykaczewski, Ryan R; Bograd, Steven J; Peterson, William T

2014-09-19

365

Six centuries of variability and extremes in a coupled marine-terrestrial ecosystem  

NASA Astrophysics Data System (ADS)

Reported trends in the mean and variability of coastal upwelling in eastern boundary currents have raised concerns about the future of these highly productive and biodiverse marine ecosystems. However, the instrumental records on which these estimates are based are insufficiently long to determine whether such trends exceed preindustrial limits. In the California Current, a 576-year reconstruction of climate variables associated with winter upwelling indicates that variability increased over the latter 20th century to levels equaled only twice during the past 600 years. This modern trend in variance may be unique, because it appears to be driven by an unprecedented succession of extreme, downwelling-favorable, winter climate conditions that profoundly reduce productivity for marine predators of commercial and conservation interest.

Black, Bryan A.; Sydeman, William J.; Frank, David C.; Griffin, Daniel; Stahle, David W.; García-Reyes, Marisol; Rykaczewski, Ryan R.; Bograd, Steven J.; Peterson, William T.

2014-09-01

366

California Solar Initiative California Public Utilities Commission  

E-print Network

California Solar Initiative California Public Utilities Commission Staff Progress Report July 2008 #12;California Solar Initiative, CPUC Staff Progress Report, July 2008: Zerull Location: San Rafael, CA System size: 14 kW Funded by the California Solar Initiative

367

A 115-year ?15N record of cumulative nitrogen pollution in California serpentine grasslands  

NASA Astrophysics Data System (ADS)

Until the 1980s, California’s biodiverse serpentine grasslands were threatened primarily by development and protected by reserve creation. However, nitrogen (N) fertilization due to increasing fossil fuel emissions in the expanding Bay Area is thought to be contributing to rapid, recent invasion of these ecosystems by exotic annual grasses that are displacing rare and endemic serpentine species. Documenting the cumulative effects of N deposition in this ecosystem can direct policy and management actions to mitigate the role of N deposition in its transformation. Natural abundance stable isotopes of N in vegetation have been increasingly used as bio-indicators of N deposition patterns and subsequent changes to plant N cycling and assimilation. However, the long-term record of atmospheric reactive N enrichment and the resulting changes in ecosystem N dynamics have yet to be adequately reconstructed in many ecosystems. Museum archives of vascular plant tissue are valuable sources of materials to reconstruct temporal and spatial isotopic patterns of N inputs to ecosystems. Here, we present N stable isotope data from archived and current specimens of an endemic California serpentine grassland species, leather oak (Quercus durata), since 1895 across the greater San Francisco Bay region. We measured spatial and temporal trends in stable isotope composition (?15N and ?13C) and concentration (%N and %C) of historical and current samples of leather oak leaves from sites within the Bay Area, impacted by increasing development, and sites northeast of the Bay Area, with significantly lower rates of urbanization and industrialization. Specifically, we sampled dry museum and fresh leaf specimens from serpentine sites within Lake (n=27) and Santa Clara (n=30) counties dating from 1895 to 2010. Leaf ?15N values were stable from 1895 to the 1950s and then decreased strongly throughout the last 50 years as fossil fuel emissions rapidly increased in the Bay Area, indicating that N pollution is being retained in serpentine grassland ecosystems. Leaf ?15N values in the high-deposition region declined at a rate of -0.041‰ yr-1, while leaf ?15N values in the low-deposition region did not show a strong pattern. In both regions, leaf ?13C values declined through time as atmospheric CO2 concentrations increased in response to fossil fuel combustion (the Suess effect). Leaf %N and %C values did not present any clear patterns at sites within or outside of the Bay Area. We conclude that using natural abundance stable isotope values in leaves can indicate variation in N pollution inputs across wide spatial and temporal scales and that archived plant samples can provide valuable baselines against which to assess changes in regional N cycling and subsequent ecological impacts on vegetation.

Vallano, D.; Zavaleta, E. S.

2010-12-01

368

167 Prospectus California Margin  

E-print Network

. Each of the three transects across the California Current will compare deep-water sites near the core), for those sites that require it, can be obtained from the following World Wide Web site: http margin, Deep Sea Drilling Project (DSDP) Leg 63, occurred immediately before the first deployment

369

Examining the Effects of Pollution on Ecosystems  

NSDL National Science Digital Library

In this lesson students become familiar with several types of tests used to measure the environmental effects of hazardous waste pollution. In the process, they learn that no single assessment procedure is applicable to all ecosystems and no single test is adequate to assess pollution impacts on an entire ecosystem. They also examine a case study of a tidal bay and discuss the limitations of current ecosystem assessment methods for establishing cause-and-effect relationships, especially for mixtures of chemicals in the environment.

370

PHOTOCHEMICAL AIR POLLUTANT EFFECTS ON MIXED CONIFER ECOSYSTEMS  

EPA Science Inventory

In 1972, a multi-disciplinary team of ecologists assembled to monitor and analyze some of the ecological consequences of photochemical oxidant air pollutants in California Mixed Conifer Forest ecosystems of the San Bernardino Mountains east of Los Angeles. The purposes included g...

371

Nitrous oxide emissions and isotopic composition in urban and agricultural systems in southern California  

NASA Astrophysics Data System (ADS)

Nitrous oxide (N2O) is a powerful greenhouse gas increasing in atmospheric mixing ratio and linked to increasing amounts of reactive N in the environment, particularly fertilizer use in agriculture. The consequences of urbanization of agricultural land for global and regional N2O emissions are unclear, due to high spatial and temporal variability of fluxes from different ecosystems and relatively few studies of urban ecosystems. We measured fluxes and the stable isotope composition (?15N and ?18O) of N2O over 1 year in urban (ornamental lawns and athletic fields) and agricultural (corn and vegetable fields) ecosystems near Los Angeles, California, United States. We found that urban landscapes (lawns and athletic fields) have annual N2O fluxes equal to or greater than agricultural fields. Fertilization rates of urban landscapes were equal to or greater than agricultural fields, with comparable N2O emissions factors. ?15N and ?18O of N2O varied widely in all ecosystems, and were not consistent with ecosystem type, season, soil moisture, or temperature. There was, however, a consistent response of ?15N-N2O to pulses of N2O emission following fertilization, with an initial depletion in ?15N relative to prefertilization values, then gradual enrichment to background values within about 1 week. Preliminary scaling calculations indicated that N2O emissions from urban landscapes are approximately equal to or greater than agricultural emissions in urbanized areas of southern California, which further implies that current estimates of regional N2O emissions (based on agricultural land area) may be too low.

Townsend-Small, Amy; Pataki, Diane E.; Czimczik, Claudia I.; Tyler, Stanley C.

2011-03-01

372

California's Accountability System and the API. Expert Report. Submitted for: Eliezer Williams vs. State of California.  

ERIC Educational Resources Information Center

This paper was presented as expert testimony in the Williams vs. State of California class action lawsuit. That case, filed on behalf of California public schoolchildren, charged the State with denying thousands of students the basic tools for a sound education. This paper addresses whether California's current output-based accountability system…

Russell, Michael

373

Effects of ozone on ecosystems -- ecosystem indicators of concern  

SciTech Connect

Ozone has been recognized as an important cause of damage to crops since the 1950s. Damage to trees was first identified in the 1960s and is now known to be widespread in both North America and Europe. Most impact studies have emphasized the importance of determining growth losses attributable to ozone and as a result have concentrated on species of commercial importance. This is illustrated by the critical loads approach to ozone risk assessment in Europe, which is currently based on the AOT40 -- 10 ppmh threshold. At higher levels, it has been argued that a 10% growth reduction occurs in European beech (Fagus sylvatica). Such an approach suffers from a number of serious limitations, not least the widespread impacts on ecosystems that may occur at lower ozone exposures and the very poor quantitative basis for setting this threshold. In Europe, there has been increasing emphasis on the conservation and management of species without any direct economic importance. This has arisen from a growing environmental awareness of the general public. The trend has been accelerated by the perceived environmental benefits of the large amounts of land that has been taken out of agricultural production (as a result of the ``set-aside`` policy of the European Union) and the public concern about the ecological and environmental impacts of industrial forestry. In agricultural landscapes, hedgerow species and weed species are being looked at as important parts of the agricultural ecosystem. In particular, weed species are an important part of the food chain for the wildlife present in such ecosystems. In forests, much greater emphasis is being given to the authenticity of the forest ecosystems. Particular emphasis is being given to ecosystem management techniques such as continuous cover forestry and the furthering of natural regeneration.

Innes, J.L. [Swiss Federal Inst. for Forest, Snow and Landscape Research, Birmensdorf (Switzerland)

1998-12-31

374

California Data Exchange Center  

NSDL National Science Digital Library

At the California Data Exchange Center website, the California Department of Water Resources provides access to an array of operational hydrologic data. Within the River Stages and Flow Data link, visitors will find river stage maps, river schematics, information on various rivers, and daily hydrologic summaries. The website provides snow information including snow sensor plots, water supply conditions, reservoir data, and reports. Individuals can view numerous satellite images and water- and weather-related forecasts. The data query tools offer an easy way to search historical and current data, data plots and graphs, and station information.

375

Multi-proxy reconstructions and the power of integration across marine, terrestrial, and freshwater ecosystems. (Invited)  

NASA Astrophysics Data System (ADS)

Over the past decade, dendrochronology (tree-ring analysis) techniques have been increasingly applied to growth increments of various bivalve, fish, and coral species. In particular, the use of crossdating ensures that all increments in a dataset have assigned the correct calendar year of formation and that the resulting chronology is exactly placed in time. Such temporal alignment facilitates direct comparisons among chronologies that span diverse taxa and ecosystems, illustrating the pervasive, synchronizing influence of climate from alpine forests to the continental slope. Such an approach can be particularly beneficial to reconstructions in that each species captures climate signals from its unique 'perspective' of life history and habitat. For example, combinations of tree-ring data and chronologies for the long-lived bivalve Pacific geoduck (Panopea generosa) capture substantially more variance in regional sea surface temperatures than either proxy could explain alone. Just as importantly, networks of chronologies spanning multiple trophic levels can help identify climate variables critical to ecosystem functioning, which can then be targeted to generate most biologically relevant reconstructions possible. Along the west coast of North America, fish and bivalve chronologies in combination with records of seabird reproductive success indicate that winter sea-level pressure is closely associated with California Current productivity, which can be hind-cast over the past six centuries using coastal tree-ring chronologies. Thus, multiple proxies not only increase reconstruction skill, but also help isolate climate variables most closely linked to ecosystem structure and functioning.

Black, B.

2013-12-01

376

Coral Reef Ecosystems  

NSDL National Science Digital Library

The Coral Reef Ecosystems SciPack explores the unique and diverse ecosystem of the coral reef. The focus is on Standards and Benchmarks related to populations and ecosystems using coral reefs and their immediate environment as an example. Because the Standards and Benchmarks present the concepts of populations and ecosystems generically, without reference to a specific ecosystem or the organisms in the system, coral reefs are used to provide the context through which concepts in a marine ecosystem are explored.In addition to comprehensive inquiry-based learning materials tied to Science Education Standards and Benchmarks, the SciPack includes the following additional components:? Pedagogical Implications section addressing common misconceptions, teaching resources and strand maps linking grade band appropriate content to standards. ? Access to one-on-one support via e-mail to content "Wizards".? Final Assessment which can be used to certify mastery of the concepts.Learning Outcomes:Coral Reef Ecosystems: The Living Reef? Identify coral polyp structures and describe their functions.? Describe photosynthesis in the coral environment.? Describe the evolution of a typical reef system.? Use the shape of an individual coral to identify its common name, and classify entire coral reef ecosystems based on shape and location. ? Describe the process of coral polyp reproduction and growth.? Identify how the features and/or behavioral strategies of coral reef inhabitants enable them to survive in coral reef environments.Coral Reef Ecosystems: The Abiotic Setting? Identify the characteristics of an ecosystem, and describe the interdependence between biotic and abiotic features in an ecosystem.? Describe how the following abiotic factors provide coral with the energy needed to survive and grow within their ecosystem: sunlight, water, oxygen, and carbon dioxide.? Describe the optimal environmental conditions for coral reef growth, and explain the process of coral reef development (including the role of available sunlight and calcium).? Explain how the following environmental factors might affect coral ecosystems: increase in dissolved CO2, changes in global temperatures, increase in ocean water turbidity through water pollution.Coral Reef Ecosystems: Interdependence? Identify and label key components of food chains and food webs in a coral reef ecosystem.? Describe key relationships among plants and animals in the coral reef ecosystem: predator and prey relationships, producer and consumer relationships, and symbiotic relationships (mutualism, commensalisms, parasitism).? Recognize the direction that energy travels through food chains and food webs.? Explain that materials (chemical elements) and natural resources are recycled in coral reef ecosystems and reappear in different forms.? Describe the primary ecological succession events within a typical coral reef ecosystem.Coral Reef Ecosystems: Ecosystems in Crisis? Describe ways in which human activities directly impact coral reef ecosystems (resource and recreational uses).? Describe ways in which human activities indirectly impact coral reef ecosystems (by changing the physical conditions, pollution, changes in the water chemistry, etc.).? Explain how human activity may decrease the reefs ability to recover from natural occurrences. ? Explain the effects of increased predation or disease on a reef ecosystem.? Describe the effect of habitat loss on the reef ecosystem.? Describe the effects of weather and climate change on a healthy and weakened reef ecosystem.

National Science Teachers Association (NSTA)

2007-03-28

377

California Fires  

Atmospheric Science Data Center

article title:  Smoke from Station Fire Blankets Southern California     ... growth of wildfires throughout southern California. The Station fire began August 26, 2009, in La Canada/Flintridge, not far from ... (152 miles) wide. Several pyrocumulus clouds, created by the Station fire, are visible above the smoke plumes rising from the San Gabriel ...

2014-05-15

378

California Condor  

USGS Multimedia Gallery

California condors are one of the most endangered birds in North America. In the early 1990s, captive-bred condors were reintroduced into the wild in California. As of January 2010, about 190 condors now live in the wild and more reintroductions are being considered. To facilitate this, USGS researc...

379

Current Cites  

NSDL National Science Digital Library

With the ever-growing interest in information technology and digital initiatives and projects, the Current Cites website will be of great interest to persons working in these various fields. Edited by Roy Tennant (a librarian working at the California Digital Library in Oakland), Current Cites is a monthly publication that contains 10-15 annotated citations of the best literature currently available in the field of information technology. Of course, visitors to the site may elect to sign up to receive Current Cites every month, or they may peruse the contents of the publication back to its founding in August 1990. Equally helpful is the Bibliography On-Demand feature that allows users to construct their own bibliography culled from the Current Cites database of bibliographic citations. Additionally, the items that are freely available on the Internet are also retrieved and indexed so that users may perform an article search of the full-text of these various items.

380

Baltic Ecosystem Adaptive Management  

E-print Network

1 Baltic Ecosystem Adaptive Management �stersjöforskning för en hållbar förvaltning av havet #12;2 Baltic Ecosystem Adaptive Management, BEAM, är ett tvärvetenskapligt forskningsprogram med målet att vårt unika innanhav beror mycket på hur vi väljer att vårda det. Baltic Ecosystem Adaptive Management

381

California Department of Transportation  

NSDL National Science Digital Library

The California Department of Transportation (CALTRANS) manages over 50,000 miles of California's highway and freeway lanes, provides inter-city rail services, and also works on a host of other transportation initiatives. Visitors can dive right in via the Highlights section, which offers an overview of the California State Rail Plan, information about webinars, and links to long-term transit feasibility studies. Other sections of the site cover Travel, Business, Engineering, News, and Maps. This last area contains the QuickMap, which offers a real-time map of current traffic conditions, along with maps designed for truckers and motor home owners. The Engineering section contains information about ongoing projects, along with financial information and planning documents. Finally, the site includes a separate page about the Bay Bridge and links to press releases and video clips.

2013-08-12

382

Combined climate- and prey-mediated range expansion of Humboldt squid (Dosidicus gigas), a large marine predator in the California Current System.  

PubMed

Climate-driven range shifts are ongoing in pelagic marine environments, and ecosystems must respond to combined effects of altered species distributions and environmental drivers. Hypoxic oxygen minimum zones (OMZs) in midwater environments are shoaling globally; this can affect distributions of species both geographically and vertically along with predator-prey dynamics. Humboldt (jumbo) squid (Dosidicus gigas) are highly migratory predators adapted to hypoxic conditions that may be deleterious to their competitors and predators. Consequently, OMZ shoaling may preferentially facilitate foraging opportunities for Humboldt squid. With two separate modeling approaches using unique, long-term data based on in situ observations of predator, prey, and environmental variables, our analyses suggest that Humboldt squid are indirectly affected by OMZ shoaling through effects on a primary food source, myctophid fishes. Our results suggest that this indirect linkage between hypoxia and foraging is an important driver of the ongoing range expansion of Humboldt squid in the northeastern Pacific Ocean. PMID:24443361

Stewart, Julia S; Hazen, Elliott L; Bograd, Steven J; Byrnes, Jarrett E K; Foley, David G; Gilly, William F; Robison, Bruce H; Field, John C

2014-06-01

383

Living Things: Habitats & Ecosystems  

NSDL National Science Digital Library

Text and photographs regarding habitats, populations and communities, biomes, niches and ecosystems in general with numerous links to lessons, activities, and organizations on specific subtopics in ecology.

2009-01-01

384

Global Conservation of Biodiversity and Ecosystem Services  

NSDL National Science Digital Library

This peer-reviewed article from the November 2007 issue of BioScience examines conservation strategies to preserve biodiversity and ecosystem services.Habitat destruction has driven much of the current biodiversity extinction crisis, and it compromises the essential benefits, or ecosystem services, that humans derive from functioning ecosystems. Securing both species and ecosystem services might be accomplished with common solutions. Yet it is unknown whether these two major conservation objectives coincide broadly enough worldwide to enable global strategies for both goals to gain synergy. In this article, we assess the concordance between these two objectives, explore how the concordance varies across different regions, and examine the global potential for safeguarding biodiversity and ecosystem services simultaneously. We find that published global priority maps for biodiversity conservation harbor a disproportionate share of estimated terrestrial ecosystem service value (ESV). Overlap of biodiversity priorities and ESV varies among regions, and in areas that have high biodiversity priority but low ESV, specialized conservation approaches are necessary. Overall, however, our findings suggest opportunities for safeguarding both biodiversity and ecosystem services. Sensitivity analyses indicate that results are robust to known limitations of available ESV data. Capitalizing on these opportunities will require the identification of synergies at fine scales, and the development of economic and policy tools to exploit them.

Will Turner (University of the Philippines; World Agroforestry Center)

2007-11-01

385

Multiple states in river and lake ecosystems.  

PubMed Central

Nonlinear models of ecosystem dynamics that incorporate positive feedbacks and multiple, internally reinforced states have considerable explanatory power. However, linear models may be adequate, particularly if ecosystem behaviour is primarily controlled by external processes. In lake ecosystems, internal (mainly biotic) processes are thought to have major impacts on system behaviour, whereas in rivers, external (mainly physical) factors have traditionally been emphasized. We consider the hypothesis that models that exhibit multiple states are useful for understanding the behaviour of lake ecosystems, but not as useful for understanding stream ecosystems. Some of the best-known examples of multiple states come from lake ecosystems. We review some of these examples, and we also describe examples of multiple states in rivers. We conclude that the hypothesis is an oversimplification; the importance of physical forcing in rivers does not eliminate the possibility of internal feedbacks that create multiple states, although in rivers these feedbacks are likely to include physical as well as biotic processes. Nonlinear behaviour in aquatic ecosystems may be more common than current theory indicates. PMID:12079525

Dent, C Lisa; Cumming, Graeme S; Carpenter, Stephen R

2002-01-01

386

Hawaiian Ecosystems at Risk Project  

NSDL National Science Digital Library

The Hawaiian Ecosystems at Risk Project works "to provide technology, methods, and information to decision-makers, resource managers, and the general public to help support effective science-based management of harmful non-native species in Hawaii and the Pacific." Current and past supporters of the HEAR project include the U.S. Geologic Survey, Pacific Island Ecosystems Research Center, University of Hawaii, National Biological Information Infrastructure-Pacific Basin Information Node, and others. The HEAR website links to a plethora of online resources including: full-text articles and reports, an Alien Species in Hawaii Information Index, A Global Compendium of Weeds, literature references, species fact sheets, numerous images, and more. HEAR also hosts electronic mailing lists, and bulletin boards for both job and general announcements including postings for professional meetings, and research grant opportunities.

387

Evaluating the Spatial Distribution of Toxic Air Contaminants in Multiple Ecosystem Indicators in the Sierra Nevada-Southern Cascades  

NASA Astrophysics Data System (ADS)

Toxic air contaminants originating from agricultural areas of the Central Valley in California threaten vulnerable sensitive receptors including surface water, vegetation, snow, sediments, fish, and amphibians in the Sierra Nevada-Southern Cascades region. The spatial distribution of toxic air contaminants in different ecosystem indicators depends on variation in atmospheric concentrations and deposition, and variation in air toxics accumulation in ecosystems. The spatial distribution of organic air toxics and mercury at over 330 unique sampling locations and sample types over two decades (1990-2009) in the Sierra Nevada-Southern Cascades region were compiled and maps were developed to further understand spatial patterns and linkages between air toxics deposition and ecological effects. Potential ecosystem impacts in the Sierra Nevada-Southern Cascades region include bioaccumulation of air toxics in both aquatic and terrestrial ecosystems, reproductive disruption, and immune suppression. The most sensitive ecological end points in the region that are affected by bioaccumulation of toxic air contaminants are fish. Mercury was detected in all fish and approximately 6% exceeded human consumption thresholds. Organic air toxics were also detected in fish yielding variable spatial patterns. For amphibians, which are sensitive to pesticide exposure and potential immune suppression, increasing trends in current and historic use pesticides are observed from north to south across the region. In other indicators, such as vegetation, pesticide concentrations in lichen increase with increasing elevation. Current and historic use pesticides and mercury were also observed in snowpack at high elevations in the study area. This study shows spatial patterns in toxic air contaminants, evaluates associated risks to sensitive receptors, and identifies data gaps. Future research on atmospheric modeling and information on sources is needed in order to predict which ecosystems are the most sensitive to toxic air contaminants in the Sierra Nevada-Southern Cascades region.

Nanus, L.; Simonich, S. L.; Rocchio, J.; Flanagan, C.

2013-12-01

388

40 CFR 230.23 - Current patterns and water circulation.  

Code of Federal Regulations, 2012 CFR

...Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current patterns and water circulation. ...circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces...

2012-07-01

389

40 CFR 230.23 - Current patterns and water circulation.  

Code of Federal Regulations, 2010 CFR

...Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current patterns and water circulation. ...circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces...

2010-07-01

390

40 CFR 230.23 - Current patterns and water circulation.  

Code of Federal Regulations, 2011 CFR

...Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current patterns and water circulation. ...circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces...

2011-07-01

391

40 CFR 230.23 - Current patterns and water circulation.  

Code of Federal Regulations, 2013 CFR

...Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current patterns and water circulation. ...circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces...

2013-07-01

392

40 CFR 230.23 - Current patterns and water circulation.  

Code of Federal Regulations, 2014 CFR

...Impacts on Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.23 Current patterns and water circulation. ...circulation are the physical movements of water in the aquatic ecosystem. Currents and circulation respond to natural forces...

2014-07-01

393

An analysis of HF radar measured surface currents to determine tidal, wind-forced, and seasonal circulation in the Gulf of the Farallones, California, United States  

Microsoft Academic Search

A complete year of hourly 3 km resolution high-frequency radar measured surface currents covering the Gulf of the Farallones were analyzed with the following three primary objectives: (1) describe the seasonal surface circulation, (2) identify tidal currents, and (3) determine the influence of wind forcing. Three predominant seasonal circulation regimes were identified: relaxation, storm, and upwelling. The relaxation period exhibited

Matt K. Gough; Newell Garfield; Erika McPhee-Shaw

2010-01-01

394

University of California, Berkeley Transfer, Re-entry, &  

E-print Network

University of California, Berkeley Received: by: The goal of this program is to offer current California Community College students) Ethnicity: African-American/Black American Indian Caucasian Asian/Asian-American Hispanic

Alvarez-Cohen, Lisa

395

Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model.  

PubMed

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures. PMID:24756001

Harfoot, Michael B J; Newbold, Tim; Tittensor, Derek P; Emmott, Stephen; Hutton, Jon; Lyutsarev, Vassily; Smith, Matthew J; Scharlemann, Jörn P W; Purves, Drew W

2014-04-01

396

Emergent Global Patterns of Ecosystem Structure and Function from a Mechanistic General Ecosystem Model  

PubMed Central

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures. PMID:24756001

Emmott, Stephen; Hutton, Jon; Lyutsarev, Vassily; Smith, Matthew J.; Scharlemann, Jörn P. W.; Purves, Drew W.

2014-01-01

397

Where Will Ecosystems Go?  

SciTech Connect

Climate-induced changes in ecosystems have been both modeled and documented extensively over the past 15-20 years. Those changes occur in the context of many other stresses and interacting factors, but it is clear that many, if not most, ecosystems are sensitive to changing climate.

Janetos, Anthony C.

2008-09-29

398

Ecosystems, Teacher's Guide.  

ERIC Educational Resources Information Center

The Science Curriculum Improvement Study has developed this teacher's guide to "Ecosystems," the sixth part of a six unit life science curriculum sequence. The six basic units, emphasizing organism-environment interactions, are organisms, life cycles, populations, environments, communities, and ecosystems. They make use of scientific and…

California Univ., Berkeley. Science Curriculum Improvement Study.

399

Earth on Edge : Ecosystems  

NSDL National Science Digital Library

This site provides information about the six ecosystems on which life on Earth most heavily depends: agricultural, forest, freshwater, grassland, coastal, and urban. It is part of a Public Broadcasting System (PBS) project, which includes a discussion guide. Ecosystems are described as communities of interacting organisms and the physical environment in which they live. The goods and services that ecosystems provide are said to form the foundation of human economies. Ecosystems purify air and water, help to control climate, and produce valuable soil-services. Site users may access a discussion guide to accompany the broadcast of the video/television program, which can be used in colleges, secondary schools, and in community groups. Case studies are taken from the companion book, World Resources 2000-2001: Ecosystems and People: The Fraying Web of Life, and from Pilot Analysis of Global Ecosystems