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1

Harmful Algal Blooms (HABs)  

MedlinePLUS

... and people. Harmful algal blooms have threatened beaches, drinking water sources, and even the boating venue for the ... added certain algae associated with HABs to its Drinking Water Contaminant Candidate List. This list identifies organisms and ...

2

Approaches to monitoring, control and management of harmful algal blooms (HABs)  

PubMed Central

Virtually every coastal country in the world is affected by harmful algal blooms (HABs, commonly called “red tides”). These phenomena are caused by blooms of microscopic algae. Some of these algae are toxic, and can lead to illness and death in humans, fish, seabirds, marine mammals, and other oceanic life, typically as a result of the transfer of toxins through the food web. Sometimes the direct release of toxic compounds can be lethal to marine animals. Non-toxic HABs cause damage to ecosystems, fisheries resources, and recreational facilities, often due to the sheer biomass of the accumulated algae. The term “HAB” also applies to non-toxic blooms of macroalgae (seaweeds), which can cause major ecological impacts such as the displacement of indigenous species, habitat alteration and oxygen depletion in bottom waters. Globally, the nature of the HAB problem has changed considerably over the last several decades. The number of toxic blooms, the resulting economic losses, the types of resources affected, and the number of toxins and toxic species have all increased dramatically. Some of this expansion has been attributed to storms, currents and other natural phenomena, but human activities are also frequently implicated. Humans have contributed by transporting toxic species in ballast water, and by adding massive and increasing quantities of industrial, agricultural and sewage effluents to coastal waters. In many urbanized coastal regions, these inputs have altered the size and composition of the nutrient pool which has, in turn, created a more favorable nutrient environment for certain HAB species. The steady expansion in the use of fertilizers for agricultural production represents a large and worrisome source of nutrients in coastal waters that promote some HABs. The diversity in HAB species and their impacts presents a significant challenge to those responsible for the management of coastal resources. Furthermore, HABs are complex oceanographic phenomena that require multidisciplinary study ranging from molecular and cell biology to large-scale field surveys, numerical modelling, and remote sensing from space. Our understanding of these phenomena is increasing dramatically, and with this understanding come technologies and management tools that can reduce HAB incidence and impact. Here I summarize the global HAB problem, its trends and causes, and new technologies and approaches to monitoring, control and management, highlighting molecular probes for cell detection, rapid and sensitive toxin assays, remote sensing detection and tracking of blooms, bloom control and mitigation strategies, and the use of large-scale physical/biological models to analyze past blooms and forecast future ones. PMID:20161650

Anderson, Donald M.

2009-01-01

3

Harmful Algal Blooms  

NSDL National Science Digital Library

This NOAA website features a repository of information about Harmful Algal Blooms (HABs). It explains the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA) and describes the subsequent formation of an Interagency Task Force to develop a national HAB assessment and authorize funding for existing and new research programs on HABs. The site features links to information about current and past research programs, HAB ecological forecasting, related news articles, workshop announcements, and additional HAB information sources.

4

The Haber Bosch–harmful algal bloom (HB–HAB) link  

NASA Astrophysics Data System (ADS)

Large-scale commercialization of the Haber–Bosch (HB) process is resulting in intensification of nitrogen (N) fertilizer use worldwide. Globally N fertilizer use is far outpacing that of phosphorus (P) fertilizer. Much of the increase in N fertilizers is also now in the form of urea, a reduced form of N. Incorporation of these fertilizers into agricultural products is inefficient leading to significant environmental pollution and aquatic eutrophication. Of particular concern is the increased occurrence of harmful algal blooms (HABs) in waters receiving nutrient enriched runoff. Many phytoplankton causing HABs have physiological adaptive strategies that make them favored under conditions of elevated N : P conditions and supply of chemically reduced N (ammonium, urea). We propose that the HB-HAB link is a function of (1) the inefficiency of incorporation of N fertilizers in the food supply chain, the leakiness of the N cycle from crop to table, and the fate of lost N relative to P to the environment; and (2) adaptive physiology of many HABs to thrive in environments in which there is excess N relative to classic nutrient stoichiometric proportions and where chemically reduced forms of N dominate. The rate of HAB expansion is particularly pronounced in China where N fertilizer use has escalated very rapidly, where soil retention is declining, and where blooms have had large economic and ecological impacts. There, in addition to increased use of urea and high N : P based fertilizers overall, escalating aquaculture production adds to the availability of reduced forms of N, as does atmospheric deposition of ammonia. HABs in both freshwaters and marginal seas in China are highly related to these overall changing N loads and ratios. Without more aggressive N control the future outlook in terms of HABs is likely to include more events, more often, and they may also be more toxic.

Glibert, Patricia M.; Maranger, Roxane; Sobota, Daniel J.; Bouwman, Lex

2014-10-01

5

Forecasting Harmful Algal Blooms  

NSDL National Science Digital Library

This online newsletter gives a brief summary of societal impacts of harmful algal blooms and the Olympic Region Harmful Algal Bloom (ORHAB) project, a group funded by NOAA to forecast harmful algal blooms (HABs) along the Washington coast. The site includes colorful SeaWiFS (satellite) images of the coast during upwelling events.

Woodruff, Dana; Institute, Battelle M.

6

Harmful Algal Blooms  

NSDL National Science Digital Library

This online textbook contains detailed information about harmful algal blooms (HABs). Topics include HAB related health hazards, general information about HABs, and taxonomic information regarding different harmful algae. The site also features links to specific aforementioned topic-related sites and maps of observed blooms in Europe and North America, Florida datasets, and historical/real-time data produced by NOAA. It also contains color photographs related to HABs.

Robert R. Stewart

7

Harmful Algal Blooms  

NSDL National Science Digital Library

This comprehensive NOAA pdf file contains in depth information about harmful algal blooms (HABs) in the United States. The article contains general information about HABs, location-based assessments of HABs, and case studies of the problem. The article features color photographs of affected areas.

Administration, National O.

8

Harmful Algal Bloom Forecasting System  

NSDL National Science Digital Library

The Harmful Algal Bloom (HAB) Forecasting System provided by NOAA supplies information on the location, extent, and potential for development or movement of harmful algal blooms in the Gulf of Mexico. The forecasting system relies on satellite imagery, field observations, and buoy data to provide the large spatial scale and high frequency of observations required to assess bloom location and movements. Conditions are posted to this web page twice a week during the HAB season. Additional analysis is included in the HAB Bulletin that is provided to state and local resource managers in the region. The web page includes links to the HAB bulletin, available mapping systems, contributors, and other HAB resources.

National Ocean Service (NOS); National Oceanic and Atmospheric Administration (NOAA)

9

Red tide is an example of a Harmful Algal Bloom (HAB), which results from higher than normal growth of a tiny single-celled  

E-print Network

Red tide is an example of a Harmful Algal Bloom (HAB), which results from higher than normal growth, yellow, brown, and even green tide events. The species typically responsible for red tide blooms off as a Florida red tide to distinguish it from other red tide -producing species. Red tide in Florida

Watson, Craig A.

10

Extreme Natural Events: Harmful Algal Blooms  

NSDL National Science Digital Library

This NOAA website features a repository of information about Harmful Algal Blooms (HABs). It explains the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA) and describes the subsequent formation of an Interagency Task Force to develop a national HAB assessment and authorize funding for existing and new research programs on HABs. The site features links to information about current and past research programs, HAB ecological forecasting, related news articles, workshop announcements, and additional HAB information sources.

Public domain

11

Toxic & Harmful Algal Blooms  

NSDL National Science Digital Library

Teaching unit investigates differences between toxic and non-toxic harmful algal blooms (HABs), where they occur in U.S. waters, causative phytoplankton species, technologies for detecting blooms, which organisms in the food web are affected and how, effects of specific toxins on humans. Five lessons contain: background and glossary; instructions for classroom and lab activities; online data; web links for further study. Lessons are aligned to teaching standards.

12

Toxic and Harmful Algal Blooms  

NSDL National Science Digital Library

Primarily through the use of engaging graphics, this resource outlines where Toxic and Harmful Algal Blooms (HABs) occur in U.S. waters. It also addresses the differences between toxic and non-toxic HABs, which organisms in the food web are affected, how specific toxins work and the symptoms associated with them, and the causative phytoplankton species.

Laboratory, Bigelow

13

Red Tide and Harmful Algal Blooms  

NSDL National Science Digital Library

This Project Oceanography pdf document contains information and activities related to red tide and harmful algal blooms (HABs). The activities and lesson plans are designed for elementary school, middle school, and may be adapted for high school students. Articles include: harmful algal blooms, Florida red tide, implications of harmful algal blooms, and student information about harmful algal blooms. Activities are introduced with background information and include: "Growing Algae" and "Algal Explosion." The document also features activity extension projects and a glossary of terms.

Project Oceanography

14

High Frequency Monitoring for Harmful Algal Blooms  

EPA Science Inventory

Harmful algal blooms (HABs) are increasingly becoming a significant ecologic, economic, and social driver in the use of water resources. Cyanobacteria and their toxins play an important role in management decisions for drinking water utilities and public health officials. Online ...

15

Investigating the Ocean Algal Blooms  

NSDL National Science Digital Library

This NOAA computer-based activity is designed to teach students in grades 9-12 how satellite imagery and remote sensing can be used to monitor harmful algal blooms (HABs). This lesson teaches students how to read and interpret satellite images and how to use GIS maps and satellite images to interpret the relationship of HABs and manatee deaths. The activity features a lesson plan and a step-by-step activity containing hyperlinks that connect the student to the relevant images and maps.

Satellite, Data N.; Administration, National O.

16

The quantitative real-time PCR applications in the monitoring of marine harmful algal bloom (HAB) species.  

PubMed

In the last decade, various molecular methods (e.g., fluorescent hybridization assay, sandwich hybridization assay, automatized biosensor detection, real-time PCR assay) have been developed and implemented for accurate and specific identification and estimation of marine toxic microalgal species. This review focuses on the recent quantitative real-time PCR (qrt-PCR) technology developed for the control and monitoring of the most important taxonomic phytoplankton groups producing biotoxins with relevant negative impact on human health, the marine environment, and related economic activities. The high specificity and sensitivity of the qrt-PCR methods determined by the adequate choice of the genomic target gene, nucleic acid purification protocol, quantification through the standard curve, and type of chemical detection method make them highly efficient and therefore applicable to harmful algal bloom phenomena. Recent development of qrt-PCR-based assays using the target gene of toxins, such as saxitoxin compounds, has allowed more precise quantification of toxigenic species (i.e., Alexandrium catenella) abundance. These studies focus only on toxin-producing species in the marine environment. Therefore, qrt-PCR technology seems to offer the advantages of understanding the ecology of harmful algal bloom species and facilitating the management of their outbreaks. PMID:23247526

Penna, Antonella; Antonella, Penna; Galluzzi, Luca; Luca, Galluzzi

2013-10-01

17

NOAA New England Red Tide Information Center: More About Red Tides and Harmful Algal Blooms  

NSDL National Science Digital Library

This web page features links to information about NOAA-funded harmful algal bloom (HAB) research, HAB species, and HAB toxins and their impacts on humans, marine environments, and coastal economies. It also offers a brief description of Red Tide.

National Ocean Service (NOS)

18

Harmful Algal Blooms  

USGS Multimedia Gallery

You may notice a green, red or brown film on your favorite boating or swimming area in the summer. This coloring could mean that the water is affected by harmful algal blooms. Harmful algal blooms are an accumulation of tiny organisms known as algae and can release harmful toxins into the environmen...

2010-06-30

19

Harmful Algal Blooms  

USGS Multimedia Gallery

You may notice a green, red or brown film on your favorite boating or swimming area in the summer. This coloring could mean that the water is affected by harmful algal blooms. Harmful algal blooms are an accumulation of tiny organisms known as algae and can release harmful toxins into the environmen...

20

Ecology and Oceanography of Harmful Algal Blooms (ECOHAB)  

NSDL National Science Digital Library

This Center for Sponsored Coastal Ocean Research (CSCOR) web page features Ecology and Oceanography of Harmful Algal Blooms (ECOHAB), a funding program within NOAA that seeks to develop effective methods for prevention, control, and mitigation of harmful algal blooms (HABs). The page provides an overview of the program, offers a link to the funding announcement, and lists accomplishments of the program.

Center for Sponsored Coastal Ocean Research (CSCOR); Noaa

21

Evaluation of Harmful Algal Bloom Outreach Activities  

PubMed Central

With an apparent increase of harmful algal blooms (HABs) worldwide, healthcare providers, public health personnel and coastal managers are struggling to provide scientifically-based appropriately-targeted HAB outreach and education. Since 1998, the Florida Poison Information Center-Miami, with its 24 hour/365 day/year free Aquatic Toxins Hotline (1–888–232–8635) available in several languages, has received over 25,000 HAB-related calls. As part of HAB surveillance, all possible cases of HAB-related illness among callers are reported to the Florida Health Department. This pilot study evaluated an automated call processing menu system that allows callers to access bilingual HAB information, and to speak directly with a trained Poison Information Specialist. The majority (68%) of callers reported satisfaction with the information, and many provided specific suggestions for improvement. This pilot study, the first known evaluation of use and satisfaction with HAB educational outreach materials, demonstrated that the automated system provided useful HAB-related information for the majority of callers, and decreased the routine informational call workload for the Poison Information Specialists, allowing them to focus on callers needing immediate assistance and their healthcare providers. These results will lead to improvement of this valuable HAB outreach, education and surveillance tool. Formal evaluation is recommended for future HAB outreach and educational materials. PMID:18463727

Fleming, Lora E.; Jerez, Eva; Stephan, Wendy Blair; Cassedy, Amy; Bean, Judy A; Reich, Andrew; Kirkpatrick, Barbara; Backer, Lorraine; Nierenberg, Kate; Watkins, Sharon; Hollenbeck, Julie; Weisman, Richard

2007-01-01

22

Eutrophication and Algal Blooms  

NSDL National Science Digital Library

Eutrophication is occurring in waters around the world and can have serious effects on marine life and humans. Excess nutrients cause the algae to "bloom," which affects aquatic life by depleting oxygen; some algae species also emit neurotoxins that impact marine species directly. The first is an article from New Scientist about the recent occurrence of thousands of dead fish on Kenyan shores. Oxygen deprivation due to algal blooms has become quite serious in the Gulf of Mexico, as described in the second article from Scientific American. An article from the Minnesota Pollution Control Agency discusses how places even as far inland as Minnesota can contribute to the problem in the Gulf of Mexico. The next site from the US Environmental Protection Agency includes information about eutrophication, what causes it, why we should be concerned, and various links. The National Office for Marine Biotoxins and Harmful Algal Blooms at Woods Hole Oceanographic Institution has created the this Web site (last mentioned in the October 29, 1997 Scout Report for Science & Engineering) that gives the basics on harmful algal blooms. The National Oceanic and Atmospheric Administration (NOAA) Northwest Fisheries Science Center also has a page that includes photos and information about marine algae. NOAA also has harmful algal bloom forecasting project which uses remote sensing to help predict algal blooms. The last site is a modeling project used to predict water quality and nutrient loading in the Neuse River Estuary in North Carolina.

Lee, Amy.

2002-01-01

23

Harmful Algal Blooms  

NSDL National Science Digital Library

This Aquatic Pathobiology website features an overview of harmful algal blooms. Specific focus is given to blooms of microscopic algae occurring in the coastal waters of the United States that produce toxins and impair fish and shellfish production, either directly or indirectly, via degradation of habitats. Links are provided to detailed pages about each of the following: neurotoxic shellfish poisoning (NSP), paralytic shellfish poisoning (PSP), "Brown tide" blooms (BTB), amnesic shellfish poisoning (ASP), and blooms which do not cause illness to humans but are harmful to fish.

Andrew Kane

24

The Olympic Region Harmful Algal Blooms  

NSDL National Science Digital Library

This is the website of the Olympic Region Harmful Algal Bloom (ORHAB) partnership, which was organized to develop collaboration and cooperation among federal, state and local management agencies, coastal Indian tribes, marine resource-based businesses, public interest groups, and academic institutions. The ORHAB partnership investigates the origins of blooms of toxic algae, monitors where and when the blooms occur, assesses the environmental conditions conducive to blooms and toxification of intertidal shellfish populations, and explores methods that can be used to reduce HAB impacts on humans and the environment. Information in this website is organized into the following categories: Home, About ORHAB, HAB impacts, project plan, partnerships, benefits, meetings, gallery, sustaining ORHAB, education, and outreach.

Olympic Region Harmful Algal Bloom (ORHAB) Partnership

25

The Northwest Fisheries Science Center (NFSC) Harmful Algal Blooms Program  

NSDL National Science Digital Library

This website features the NFSC Harmful Algal Blooms (HAB) Program, which works cooperatively with other NOAA agencies and provides information concerning HABs and marine biotoxins to the public, state and federal agencies, tribes, university, and others in the Eastern Pacific region. The website provides an overview of HABs and biotoxins, NWFSC research and research partnerships, outreach information (including Red Tides and ORHAB newsletters), and links to related websites.

The Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration

26

Eye in the sky: tracking harmful algal blooms with satellite remote sensing  

NSDL National Science Digital Library

This article details an effort to use satellite imagery to track harmful algal bloom (HAB) events. The article provides basic information about HABs, how the satellite imagery will track HABs, and potential applications of this new technology. It also features colorful pictures and a map of the study area.

Chang, Hoe; Richardson, Ken; Uddstrom, Michael; Pinkerton, Matt; Science, Niwa

27

Promotion of harmful algal blooms by zooplankton predatory activity  

PubMed Central

The relationship between algae and their zooplanktonic predators typically involves consumption of nutrients by algae, grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients. Eutrophication raises nutrient levels, but does not simply increase normal predator–prey activity; rather, harmful algal bloom (HAB) events develop often with serious ecological and aesthetic implications. Generally, HAB species are outwardly poor competitors for nutrients, while their development of grazing deterrents during nutrient stress ostensibly occurs too late, after the nutrients have largely been consumed already by fast-growing non-HAB species. A new mechanism is presented to explain HAB dynamics under these circumstances. Using a multi-nutrient predator–prey model, it is demonstrated that these blooms can develop through the self-propagating failure of normal predator–prey activity, resulting in the transfer of nutrients into HAB growth at the expense of competing algal species. Rate limitation of this transfer provides a continual level of nutrient stress that results in HAB species exhibiting grazing deterrents protecting them from top-down control. This process is self-stabilizing as long as nutrient demand exceeds supply, maintaining the unpalatable status of HABs; such events are most likely under eutrophic conditions with skewed nutrient ratios. PMID:17148360

Mitra, Aditee; Flynn, Kevin J

2006-01-01

28

Harmful Algal Blooms Activity  

NSDL National Science Digital Library

In this activity, students learn about the biological and physical conditions that lead to eutrophication of a water system by using real-time data to predict the the growth of harmful algae. They also conduct research on the Internet to learn more about the causes of harmful algal blooms. Students investigate both the position of the Gulf Stream, as well as population and life cycle characteristics of harmful phytoplankton. The activity includes a worksheet and assessment questions. This resource is found in Rising Tides, a journal created for teachers and students reporting on current oceanography research conducted by NASA, NOAA, and university scientists, featuring articles, classroom activities, readings, teacher/student questions, and imagery for student investigation of marine science.

29

Multiple simultaneous detection of Harmful Algal Blooms (HABs) through a high throughput bead array technology, with potential use in phytoplankton community analysis  

PubMed Central

As an alternative to traditional, morphology-based methods, molecular techniques can provide detection of multiple species within the HAB community and, more widely, the phytoplankton community in a rapid, accurate and simultaneous qualitative analysis. These methods require detailed knowledge of the molecular diversity within taxa in order to design efficient specific primers and specific probes able to avoid cross-reaction with non-target sequences. Isolates from Florida coastal communities were sequence-analyzed and compared with the GenBank database. Almost 44% of the genotypes obtained did not match any sequence in GenBank, showing the existence of a large and still unexplored biodiversity among taxa. Based on these results and on the GenBank database, we designed 14 species-specific probes and 4 sets of specific primers. Multiple simultaneous detection was achieved with a bead array method based on the use of a flow cytometer and color-coded microspheres, which are conjugated to the developed probes. Following a parallel double PCR amplification, which employed universal primers in a singleplex reaction and a set of species-specific primers in multiplex, detection was performed in a cost effective and highly specific analysis. This multi-format assay, which required less than 4 h to complete from sample collection, can be expanded according to need. Up to 100 different species can be identified simultaneously in a single sample, which allows for additional use of this method in community analyses extended to all phytoplankton species. Our initial field trials, which were based on the 14 species-specific probes, showed the co-existence and dominance of two or more species of Karenia during toxic blooms in Florida waters. PMID:20046212

Scorzetti, G.; Brand, L.E.; Hitchcock, G.L.; Rein, K.S.; Sinigalliano, C.D.; Fell, J.W.

2008-01-01

30

Monitoring and Event Response for Harmful Algal Blooms (MERHAB)  

NSDL National Science Digital Library

This NOAA Center for Sponsored Coastal Ocean Research (CSCOR) web page features the Monitoring and Event Response for Harmful Algal Blooms (MERHAB) Program. Harmful algal blooms (HABs) are occurring with increasing frequency and duration along our shores. Nearly every coastal region is struggling to mitigate the often devastating impacts to local economies and serious human health threats associated with a variety of harmful algae. MERHAB projects have been developed to enhance existing water and shellfish monitoring programs with new technology allowing for pro-active detection of coastal HAB events. The ultimate aim of MERHAB is to help build sustainable regional partnerships that provide managers with crucial information in time for critical decisions needed to mitigate HAB impacts. The MERHAB research program is addressing the growing national HAB threat by expanding the number of coastal regions benefiting from advancements in algal identification, detection, modeling, and prediction. This page discusses the issue of HABs, research addressing the issue, and related accomplishments. A link is provided to a list of MERHAB research abstracts.

Center for Sponsored Coastal Ocean Research (CSCOR)

31

The green macroalga, Ulva lactuca, inhibits the growth of seven common harmful algal bloom species via allelopathy  

Microsoft Academic Search

Harmful algal blooms (HABs) are a significant threat to fisheries, public health, and economies around the world, and both HABs and macroalgae are often promoted by nutrient loading. We report on experiments examining the effects of the macroalga, Ulva lactuca, collected from estuaries of NY, USA, on the growth of seven common HAB species: Aureococcus anophagefferens, Chattonella marina, Cochlodinium polykrikoides,

Ying Zhong Tang; Christopher J. Gobler

2011-01-01

32

Fiber-Optic Microarray for Simultaneous Detection of Multiple Harmful Algal Bloom Species  

Microsoft Academic Search

Harmful algal blooms (HABs) are a serious threat to coastal resources, causing a variety of impacts on public health, regional economies, and ecosystems. Plankton analysis is a valuable component of many HAB monitoring and research programs, but the diversity of plankton poses a problem in discriminating toxic from nontoxic species using conventional detection methods. Here we describe a sensitive and

Soohyoun Ahn; David M. Kulis; Deana L. Erdner; Donald M. Anderson; David R. Walt

2006-01-01

33

Ensemble Methodology Using Multistage Learning for Improved Detection of Harmful Algal Blooms  

Microsoft Academic Search

The available empirical remote sensing techniques for harmful algal bloom (HAB) detection are reliant on prior observations and thresholds. These techniques tend to give high false alarm rate, as they are limited in spatiotemporal contextual information and decision combination techniques. We propose a multistage learning based ensemble methodology addressing the above constraints for performance improvement of HAB detection. Machine learning-based

Balakrishna Gokaraju; Surya S. Durbha; Roger L. King; Nicolas H. Younan

2012-01-01

34

Toxic and Harmful Algal Blooms Educational Activities  

NSDL National Science Digital Library

Four lesson plans focus on understanding toxic and harmful algal blooms. Designed for use in conjunction with Bigelow Laboratory's "Toxic and Harmful Algal Bloom" web site. Each module includes background, learning objectives, student preparation, and standards-related classroom or lab activity. Topics cover: role of algae in the food web; development of algal blooms; impacts and bioaccumulation of bloom-related toxins; control of blooms and role playing a community response.

35

NOAA Center of Excellence for Great Lakes and Human Health: Harmful Algal Bloom Event Response  

NSDL National Science Digital Library

This website features information about a harmful algal bloom (HAB) related project by the Center of Excellence for Great Lakes and Human Health. The focus of this research project is to determine the factors controlling microcystin production and to develop methods for determining cyanobacteria blooms from satellite imagery. Imagery is currently available, but it is unknown how to discriminate toxic Microcystis blooms from other algal blooms within the images. The combined field data and satellite image data produced from the initial efforts of this project are critical first steps in the characterization of bloom dynamics and development of future bloom forecasting tools.

National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory

36

A Geospatial Analysis of Harmful Algal Blooms along the California Coast  

NASA Astrophysics Data System (ADS)

Algal blooms are natural phenomena consisting of the rapid growth of phytoplankton populations. Some blooms have negative ecological or public health effects due to toxin production and removal of oxygen from the water column. In recent years, such "harmful algal blooms" (HABs) have been linked to human illness, economic loss from decreased fishing, and ecological damage related to marine life mortality as well as eutrophication. A notable HAB event occurred along the coast of northern California in August 2011, resulting in economic and ecological impacts of approximately $82 million. This was one of several algal blooms that occurred in fall 2011, with similar northward propagating algal blooms occurring in autumn of other years. Although the scale of the bloom impact is well-known, the spatial and temporal extent of the bloom boundary is still unclear. This study tracked the space-time pattern of numerous blooms during August-October 2011 using multiple NASA Earth observing systems in an effort to quantify and understand the structure of these recurrent bloom events. Aqua MODIS images were used to quantify surface chlorophyll-? levels, and thus to map the extent and development of all autumn algal blooms. The relation between sea surface temperature, ocean surface topography, and algal blooms was further explored with AVHRR and Jason-2 satellite data. A Generalized Additive Model (GAM) was used to identify the environmental factors most statistically influential in algal blooms and specifically in HAB events. Results from this study will assist California's Departments of Public Health and Fish & Game in mitigating and managing the impact of future harmful algal blooms.

Jensen, C.; Rothwell, R.; Johnson, E.; Condamoor, M.; Patil, M.; Largier, J. L.; Schmidt, C.

2012-12-01

37

Harmful algal blooms (HABs), dissolved organic matter (DOM), and planktonic microbial community dynamics at a near-shore and a harbour station influenced by upwelling (SW Iberian Peninsula)  

NASA Astrophysics Data System (ADS)

The surface microalgal community, including harmful species, dissolved organic matter (DOM), and bacterial and viral populations were studied during an annual cycle (November 2007-October 2008) in a Near-shore (NS) and a Harbour (H) station located in an upwelling area (Sagres, SW Iberian Peninsula). The higher water residence time, water stability and shallowness of harbours in comparison with open waters likely contributed to the differences found between stations regarding chemical variables, statistical correlations and harmful algal proliferations. Also, several differences were noticed from a previous assessment ( Loureiro et al., 2005) including higher SST, lower nitrate and chlorophyll a concentrations, along with a shift in the microplankton community structure from diatom to nanoflagellate predominance. These variations feasibly reflect the response of this dynamic system to regional environmental modifications contributing to the understanding of common patterns in environmental change trends. The division of the sampling period into (1) non-upwelling (Non-Uw), (2) "spin-up" of upwelling (SU-Uw), and (3) "spin-down" and relaxation-downwelling (SD-Rel) stages allowed the identification of natural groupings of microplankton samples by Multi Dimensional Scaling (MDS) analysis. Dissolved organic nitrogen (DON) and viruses were the most significant abiotic and biotic variables, respectively, contributing to the dissimilarities between these stages (SIMPER analysis) and, therefore, potentially affecting the microplankton community structure. Harmful algal species and a stable viral community appeared to be favoured by SD-Rel conditions. Data seem to indicate that both Gymnodinium catenatum and Heterosigma akashiwo, the most abundant potentially harmful species, have been imported into the sampling area. Also, the H location, together with potential retention sites developing around the Cabo de São Vicente upwelling centre, may contribute to the local accumulation of harmful species. The associations found between harmful algal species and bacterioplankton and virioplankton call for detailed studies in order to evaluate species-specific interactions.

Loureiro, Sofia; Reñé, Albert; Garcés, Esther; Camp, Jordi; Vaqué, Dolors

2011-05-01

38

Detection of surface algal blooms using the newly developed algorithm surface algal bloom index (SABI)  

NASA Astrophysics Data System (ADS)

Quantifying ocean colour properties has evolved over the past two decades from being able to merely detect their biological activity to the ability to estimate chlorophyll concentration using optical satellite sensors like MODIS and MERIS. The production of chlorophyll spatial distribution maps is a good indicator of plankton biomass (primary production) and is useful for the tracing of oceanographic currents, jets and blooms, including harmful algal blooms (HABs). Depending on the type of HABs involved and the environmental conditions, if their concentration rises above a critical threshold, it can impact the flora and fauna of the aquatic habitat through the introduction of the so called "red tide" phenomenon. The estimation of chlorophyll concentration is derived from quantifying the spectral relationship between the blue and the green bands reflected from the water column. This spectral relationship is employed in the standard ocean colour chlorophyll-a (Chlor-a) product, but is incapable of detecting certain macro-algal species that float near to or at the water surface in the form of dense filaments or mats. The ability to accurately identify algal formations that sometimes appear as oil spill look-alikes in satellite imagery, contributes towards the reduction of false-positive incidents arising from oil spill monitoring operations. Such algal formations that occur in relatively high concentrations may experience, as in land vegetation, what is known as the "red-edge" effect. This phenomena occurs at the highest reflectance slope between the maximum absorption in the red due to the surrounding ocean water and the maximum reflectance in the infra-red due to the photosynthetic pigments present in the surface algae. A new algorithm termed the surface algal bloom index (SABI), has been proposed to delineate the spatial distributions of floating micro-algal species like for example cyanobacteria or exposed inter-tidal vegetation like seagrass. This algorithm was specifically modelled to adapt to the marine habitat through its inclusion of ocean-colour sensitive bands in a four-band ratio-based relationship. The algorithm has demonstrated high stability against various environmental conditions like aerosol and sun glint.

Alawadi, Fahad

2010-10-01

39

Worst New England Harmful Algal Bloom in 30 Years  

NSDL National Science Digital Library

This online 2005 article reports the most severe bloom since 1972 of the microscopic alga, Alexandrium fundyense, which spread from Maine to Massachusetts, resulting in extensive commercial and recreational shellfish harvesting closures to protect humans from paralytic shellfish poisoning (PSP). The article discusses harmful algal blooms (HABs) and reports how NOAA-funded research is addressing the problem. It includes links to research programs, up-to-date information about shellfish closures, images of the causative microbes, related press releases and legislation, and other informational sources.

Center for Sponsored Coastal Ocean Research (CSCOR); Noaa

40

HABHRCA: The Harmful Algal Bloom and Hypoxia Research and Control Act  

NSDL National Science Digital Library

This website describes HABHRCA, a legislative Act that authorizes funding for research on harmful algal blooms (HABs) and hypoxia to advance scientific understanding and our ability to detect, assess, predict, control, and mitigate events. The site discusses the Act, gives an overview of The Interagency Task Force on Harmful Algal Blooms and Hypoxia, and features links to past plans and reports called for by HABHRCA 1998. It also serves as a jumping point to conferences and workshops, pertinent documents, and other informational resources.

Center for Sponsored Coastal Ocean Research (CSCOR); Noaa

41

The spatial and temporal characteristics of harmful algal blooms in the southwest Bohai sea  

NASA Astrophysics Data System (ADS)

Harmful algal blooms (HABs) are harmful to coastal ecosystems, fisheries, the aquaculture industry, and even human health, thus they have received great attention worldwide. In this study, geostatistical tools in Geographic information system (GIS) were used to analyze HAB data collected over the last 11 years in the southwest Bohai Sea with the goal of detecting spatial and temporal characteristics of HAB events in this area. The seasonality, trend of HAB occurrences and the spatial pattern of HAB events were examined by time-series analysis and nearest neighbor analysis, respectively. The frequency of HAB occurrences was mapped using kernel density estimation, and the harm caused by HAB events was assessed and then categorized using a characteristic-based empirical model. The occurrences of HABs not only exhibited significant seasonality and a "single peak" trend in time but also were clustered in space. HABs had both a high frequency of occurrence and a high harm in the north Bohai Bay and the Yellow River estuary. In addition, HABs posed a high harm in the nearshore area near the city of Huanghua in Bohai Bay and the offshore area in the middle Bohai Bay; thus, HAB monitoring and/or management should be concentrated in these locales. Compared to previous descriptions, this research utilized a visualizable approach to more fully identify the scope, distribution, and characteristics of HAB occurrences in the southwest Bohai Sea, thus providing useful information to support the implementation of a monitoring and management program for HABs.

Wu, Zaixing; Yu, Zhiming; Song, Xiuxian; Yuan, Yongquan; Cao, Xihua; Liang, Yubo

2013-05-01

42

Algal blooms and public health  

SciTech Connect

Alterations in coastal ecology are expanding the geographic extent, frequency, magnitude, and species complexity'' of algal blooms throughout the world, increasing the threat of fish and shellfish poisonings, anoxia in marine nurseries, and of cholera. The World Health Organization and members of the medical profession have described the potential health effects of global climate change. They warn of the consequences of increased ultraviolet-B (UV-B) rays and of warming: the possible damage to agriculture and nutrition, and the impact on habitats which may alter the distribution of vector-borne and water-based infectious diseases. Algal growth due to increased nitrogen (N) and phosphorus (P) and warming are already affecting marine microflora and aquatic plants; and there is now clear evidence that marine organisms are a reservoir for enteric pathogens. The pattern of cholera in the Western Hemisphere suggests that environmental changes have already begun to influence the epidemiology of this infectious disease. 106 refs.

Epstein, P.R. (Cambridge Hospital, MA (United States). Harvard Medical School)

1993-06-01

43

The role of selective predation in harmful algal blooms  

NASA Astrophysics Data System (ADS)

A feature of marine plankton communities is the occurrence of rapid population explosions. When the blooming species are directly or indirectly noxious for humans, these proliferations are denoted as harmful algal blooms (HAB). The importance of biological interactions for the appearance of HABs, in particular when the proliferating microalgae produce toxins that affect other organisms in the food web, remains still poorly understood. Here we analyse the role of toxins produced by a microalgal species and affecting its predators, in determining the success of that species as a bloom former. A three-species predator-prey model is used to define a criterion that determines whether a toxic microalga will be able to initiate a bloom in competition against a non-toxic one with higher growth rate. Dominance of the toxic species depends on a critical parameter that defines the degree of feeding selectivity by grazers. The criterion is applied to a particular simplified model and to numerical simulations of a full marine ecosystem model. The results suggest that the release of toxic compounds affecting predators may be a plausible biological factor in allowing the development of HABs.

Solé, Jordi; Garcia-Ladona, Emilio; Estrada, Marta

2006-08-01

44

Low-cost colorimeter development for the field-based detection of harmful algal blooms  

Microsoft Academic Search

The real-time detection of harmful algal bloom (HAB)-causing organisms is crucial to preventing human illness and death, animal mortalities, and significant economic losses for coastal and fishing communities. However, most identification schemes are time-consuming and costly, which limit their use for rapid risk assessment. To address this problem, a simple colorimetric test for the HAB-causing Alexandrium fundyense\\/tamarense\\/catanella dinoflagellate species complex

Janice Duy; Rosemary L. Smith; Scott D. Collins; Laurie B. Connell

2011-01-01

45

Florida Fish and Wildlife Research Institute: Harmful Algal Blooms Facts and Information  

NSDL National Science Digital Library

This comprehensive website on harmful algal blooms (HAB), maintained by the Florida Fish and Wildlife Research Institute, provides general information regarding HABs, including relevant species, terminology, and health effects, as well as information regarding the current status of red tides in Florida. Research projects underway at the Institute are described and links to publications are provided. Additionally, archived maps displaying weekly red tide counts in Florida since 2001 may be accessed from this webpage along with historical information regarding red tides in Florida.

2009-11-25

46

Freshwater Blooms  

NSDL National Science Digital Library

This Bigelow Laboratory "Special Topics" page discusses freshwater harmful algal blooms (HABs). The interactive web page describes the features of a freshwater HAB with a focus on location, organisms affected, human symptoms, toxins (neurotoxins and hepatotoxins), and causative organisms. Links are provided to other pages within the Toxic and Harmful Algal Blooms collection.

Sciences, Bigelow L.

47

Sensor Web and Data Mining Approaches for Harmful Algal Bloom Detection and Monitoring in the Gulf of Mexico Region  

Microsoft Academic Search

Harmful Algal Blooms (HABs) pose an enormous threat to the U.S. marine habitation and economy in the coastal waters. Federal and state coastal administrators have been working in devising a state-of-the-art monitoring and forecasting system for these HAB events. These modernized HAB systems provide useful and forewarning information to a varied user community. However, the lack of standardization in the

Balakrishna Gokaraju; Surya S. Durbha; Roger L. King; Nicolas H. Younan

2009-01-01

48

Can LANDSAT be used to catalog historical freshwater harmful algal blooms?  

NASA Astrophysics Data System (ADS)

Blooms of toxic algae are becoming increasingly common in freshwater lakes globally, progressively impacting human and ecosystem health in more locales around the world. Despite this growing footprint of harmful algal blooms (HABs), however, there still exist few quantitative tools for monitoring the temporal and spatial progression of HABs in individual lakes, a prerequisite for documenting and understanding their global increase. Past efforts using MODIS and MERIS to monitor blooms have been limited to studying the subset of blooms that have occurred since those instruments began collecting data (1999 and 2002, respectively) and MERIS imagery in particular is not freely available. In contrast, LANDSAT Thematic Mapper (TM) imagery is available with data starting from 1982 and is freely accessible. Therefore, if LANDSAT could be used to identify blooms, then this would be advantageous for future monitoring and research. In this work, we assess the use of LANDSAT TM for identifying the presence, spatial extent, and timing of HABs. We do this by comparing LANDSAT-generated maps of phycocyanin content in Lake Erie with literature reports of harmful algal blooms and MERIS-generated maps of cyanobacteria. Lake Erie is used as the case study because its HABs have been extensively documented in the scientific literature. Maps are generated using a linear combination of spectral ratios tested previously for Lake Erie, using the Google Earth Engine platform for data processing. We further assess the effectiveness of LANDSAT TM for identifying HABs in other bloom-impacted freshwater lakes around the world. Most of the previous work using remote sensing to identify freshwater HABs has focused on individual remote sensing platforms and individual lakes; this work contributes to knowledge by comparing across platforms and water bodies. This assessment will improve understanding of the challenges of monitoring freshwater HABs, and will contribute to the development of effective management strategies for water resources both in Lake Erie and beyond.

Ho, J. C.; Michalak, A. M.

2013-12-01

49

The physical oceanography of upwelling systems and the development of harmful algal blooms  

PubMed Central

The upwelling systems of the eastern boundaries of the world’s oceans are susceptible to harmful algal blooms (HABs) because they are highly productive, nutrient-rich environments, prone to high-biomass blooms. This review identifies those aspects of the physical environment important in the development of HABs in upwelling systems through description and comparison of bloom events in the Benguela, California and Iberia systems. HAB development is dictated by the influence of wind stress on the surface boundary layer through a combination of its influence on surface mixed-layer characteristics and shelf circulation patterns. The timing of HABs is controlled by windstress fluctuations and buoyancy inputs at the seasonal, event and interannual scales. Within this temporal framework, various mesoscale features that interrupt typical upwelling circulation patterns, determine the spatial distribution of HABs. The inner shelf in particular provides a mosaic of shifting habitats, some of which favour HABs. Changes in coastline configuration and orientation, and bottom topography are important in determining the distribution of HABs through their influence on water stratification and retention. A spectrum of coastline configurations, including headlands, capes, peninsulas, Rías, bays and estuaries, representing systems of increasing isolation from the open coast and consequent increasing retention times, are assessed in terms of their vulnerability to HABs. PMID:22053120

Pitcher, G.C.; Figueiras, F.G.; Hickey, B.M.; Moita, M.T.

2011-01-01

50

Facts about Cyanobacteria (Blue-green Algae) and Cyanobacterial Harmful Algal Blooms  

E-print Network

#12;1 Facts about Cyanobacteria (Blue-green Algae) and Cyanobacterial Harmful Algal Blooms (CyanoHABs) Cyanobacteria (blue-green algae) Cyanobacteria are bacteria that grow in water and are photosynthetic (use sunlight to create food and support life). Cyanobacteria live

51

Toxic Red Tides and Harmful Algal Blooms: A Practical Challenge in Coastal Oceanography  

NSDL National Science Digital Library

This national report to IUGG (International Union of Geodesy and Geophysics) contains links to information regarding harmful algal blooms (HABs). Written by Donald Anderson, the report includes: introduction, background, recent trends, physical/biological coupling, small-scale interactions, nutrient dynamics, emerging technologies (molecular probes, remote sensing, models, management issues, and program and policy issues), and a list of references.

Anderson, Donald M. (Donald Mark)

2010-01-04

52

Most harmful algal bloom species are vitamin B1 and B12 auxotrophs  

PubMed Central

Eutrophication can play a central role in promoting harmful algal blooms (HABs), and therefore many HAB studies to date have focused on macronutrients (N, P, Si). Although a majority of algal species require exogenous B vitamins (i.e., auxotrophic for B vitamins), the possible importance of organic micronutrients such as B vitamins (B1, B7, B12) in regulating HABs has rarely been considered. Prior investigations of vitamins and algae have examined a relatively small number of dinoflagellates (n = 26) and a paucity of HAB species (n = 4). In the present study, the vitamin B1, B7, and B12 requirements of 41 strains of 27 HAB species (19 dinoflagellates) were investigated. All but one species (two strains) of harmful algae surveyed required vitamin B12, 20 of 27 species required B1, and 10 of 27 species required B7, all proportions higher than the previously reported for non-HAB species. Half-saturation (Ks) constants of several HAB species for B1 and B12 were higher than those previously reported for other phytoplankton and similar to vitamin concentrations reported in estuaries. Cellular quotas for vitamins suggest that, in some cases, HAB demands for vitamins may exhaust standing stocks of vitamins in hours to days. The sum of these findings demonstrates the potentially significant ecological role of B-vitamins in regulating the dynamics of HABs. PMID:21068377

Tang, Ying Zhong; Koch, Florian; Gobler, Christopher J.

2010-01-01

53

THE FUTURE OF HARMFUL ALGAL BLOOMS: AN EMPIRICAL APPROACH TO PREDICTING THE COMBINED IMPACTS OF RISING CO2, TEMPERATURE, AND EUTROPHICATION  

EPA Science Inventory

Recent worldwide increases in harmful algal blooms (HABs) are almost certainly linked to cultural eutrophication of coastal environments. Virtually no attention has been given, however, to how other major anthropogenic impacts such as rising CO2 and greenhouse warmi...

54

Screening of surfactants for harmful algal blooms mitigation.  

PubMed

Screening experiments were conducted in order to find promising synthetic surfactants for harmful algal blooms (HABs) mitigation. The chemically synthesized surfactant cocamidopropyl betaine (CAPB) showed characteristics of relatively high inhibition efficiency, high biodegradability and low cost. The motility inhibition ratios of 10 mg/L CAPB on Cochlodinium polykrikoides and Alexandrium tamarense were about 60% after 5 min. The biodegradation test indicated that the half-life of CAPB in seawater was shorter than one day and 90% was biodegraded after five days under the initial concentration of 100 mg/L at 25 degrees C. Further cell lysis experiments revealed the selective lysis effect of CAPB on different HAB organisms. More than 90% of C. polykrikoides lysed at the concentration of 10 mg/L CAPB after 24 h and at 15 mg/L CAPB after 4 h, whereas the lysis effect of CAPB on A. tamarense was slight, no more than 10% after 2 h interaction with 50 mg/L CAPB. This research provided preliminary data for CAPB as a candidate in harmful algal blooms mitigation and pointed out unresolved problems for its practical application in the meantime. PMID:15111041

Sun, Xiao-Xia; Han, Kyung-Nam; Choi, Joong-Ki; Kim, Eun-Ki

2004-05-01

55

Harmful Algal Blooms: Brown Tide Blooms  

NSDL National Science Digital Library

This University of Maryland SeaGrant web page discusses brown tide blooms, particularly those caused by Aureococcus anophagefferens and Aureoumbra lagunesis in Rhode Island and Texas, respectively. The page explores the economic and ecological effects in both regions and highlights various theories regarding their formation and recurrence.

Kane, Andrew; Jacobs, Dan; The Aquatic Pathobiology Center, University of Maryland; SeaGrant

56

MULTI-COMPONENT EVALUATION TO MINIMIZE THE SPREAD OF AQUATIC INVASIVE SEAWEEDS AND HARMFUL ALGAL BLOOM MICROALGAE VIA LIVE BAIT VECTORS IN LONG ISLAND SOUND  

EPA Science Inventory

The goal of this project is to quantify the importance of bait products and associated packing materials as vectors for the introduction of non-indigenous species and harmful algal bloom (HAB)-forming microalgae to Long Island Sound. Non-native, invasive seaweeds and HAB-forming...

57

UV-Visible Spectroscopic Method and Models for Assessment and Monitoring of Harmful Algal Blooms  

NASA Technical Reports Server (NTRS)

The development of an enhanced predictive and early warning capability for the occurrence and impact of harmful algal blooms (HABs) would be of great benefit to coastal communities. A critical issue for early detection and monitoring of HABs is the need to detect harmful algal species within a mixed-species phytoplankton assemblage. Possession of UV-absorbing compounds called mycosporine-like amino acids (MAAs) may be one factor that allows HAB species to out-compete their phytoplankton neighbors. Possession of MAAs, which we believe can be inferred from strong UV-absorption signals in phytoplankton absorption coefficients, can be used as a flag for potential HAB outbreak. The goal of this project was to develop a solar simulating UV-visible incubator to grow HAB dinoflagellates, to begin MAA analysis of samples collected on global cruises, and to carry out initial experiments on HAB dinoflagellate species in pure culture. Our scientific objectives are to quantify MAA production and spectral induction mechanisms in HAB species, to characterize spectral absorption of MAAs, and to define the ecological benefit of MAAs (i.e. photoprotection). Data collected on cruises to the global oceans will be used to parameterize phytoplankton absorption in the UV region, and this parameterization could be incorporated into existing models of seawater optical properties in the UV spectral region. Data collected in this project were used for graduate fellowship applications by Elizabeth Frame. She has been awarded an EPA STAR fellowship to continue the work initiated by this project.

Mitchell, B. Greg

2000-01-01

58

Centers for Oceans and Human Health: a unified approach to the challenge of harmful algal blooms  

PubMed Central

Background Harmful algal blooms (HABs) are one focus of the national research initiatives on Oceans and Human Health (OHH) at NIEHS, NOAA and NSF. All of the OHH Centers, from the east coast to Hawaii, include one or more research projects devoted to studying HAB problems and their relationship to human health. The research shares common goals for understanding, monitoring and predicting HAB events to protect and improve human health: understanding the basic biology of the organisms; identifying how chemistry, hydrography and genetic diversity influence blooms; developing analytical methods and sensors for cells and toxins; understanding health effects of toxin exposure; and developing conceptual, empirical and numerical models of bloom dynamics. Results In the past several years, there has been significant progress toward all of the common goals. Several studies have elucidated the effects of environmental conditions and genetic heterogeneity on bloom dynamics. New methods have been developed or implemented for the detection of HAB cells and toxins, including genetic assays for Pseudo-nitzschia and Microcystis, and a biosensor for domoic acid. There have been advances in predictive models of blooms, most notably for the toxic dinoflagellates Alexandrium and Karenia. Other work is focused on the future, studying the ways in which climate change may affect HAB incidence, and assessing the threat from emerging HABs and toxins, such as the cyanobacterial neurotoxin ?-N-methylamino-L-alanine. Conclusion Along the way, many challenges have been encountered that are common to the OHH Centers and also echo those of the wider HAB community. Long-term field data and basic biological information are needed to develop accurate models. Sensor development is hindered by the lack of simple and rapid assays for algal cells and especially toxins. It is also critical to adequately understand the human health effects of HAB toxins. Currently, we understand best the effects of acute toxicity, but almost nothing is known about the effects of chronic, subacute toxin exposure. The OHH initiatives have brought scientists together to work collectively on HAB issues, within and across regions. The successes that have been achieved highlight the value of collaboration and cooperation across disciplines, if we are to continue to advance our understanding of HABs and their relationship to human health. PMID:19025673

Erdner, Deana L; Dyble, Julianne; Parsons, Michael L; Stevens, Richard C; Hubbard, Katherine A; Wrabel, Michele L; Moore, Stephanie K; Lefebvre, Kathi A; Anderson, Donald M; Bienfang, Paul; Bidigare, Robert R; Parker, Micaela S; Moeller, Peter; Brand, Larry E; Trainer, Vera L

2008-01-01

59

Spatial, seasonal and species variations of harmful algal blooms in the South Yellow Sea and East China Sea  

Microsoft Academic Search

The occurrences of harmful algal blooms (HABs), in terms of frequency and area in the Chinese coastal waters, have been increasing\\u000a since 1980s and caused considerable economic losses. In the present study, we have analyzed spatial and seasonal characteristics\\u000a of HAB events in the southern Yellow Sea and East China Sea along Chinese coast from 1933 to 2004. With a

DanLing Tang; BaoPing Di; Guifeng Wei; I-Hsun Ni; Im Sang Oh; SuFen Wang

2006-01-01

60

Harmful Algal Blooms & Muck What's the Difference?  

E-print Network

as Cladophora, can be mistaken for each other simply because people may associate an algal bloom with either type. However, both represent significantly different species. Unlike green algae such as Cladophora and rapidly recycling nutrients that stimulate growth. Muck: Cladophora or Spirogyra Can wash up on shore

61

Algal bloom in a lake in Tennessee  

NSDL National Science Digital Library

Large amounts of nutrients from agricultural runoff and pollution cause increased growth of algae. Algal blooms cause other organisms to die because the algae uses up all the oxygen in the water to grow. Eventually, this body of water will have no life in it.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-12

62

Patch recognition of algal blooms and macroalgae  

Microsoft Academic Search

Fraunhofer lines and atmospheric absorption bands interfere with the spectral location of absorption bands of photosynthetic pigments in plankton. Hyperspectral data were used to address this interference on identifying absorption bands by applying derivative analysis of radiance spectra. Algal blooms show elevated radiance data even at longer wavelengths compared to oligotrophic water and may reach radiance values of around 800

K. H. Szekielda; J. H. Bowles; D. B. Gillis; W. Snyder; W. D. Miller

2010-01-01

63

A Machine Learning Based Spatio-Temporal Data Mining Approach for Detection of Harmful Algal Blooms in the Gulf of Mexico  

Microsoft Academic Search

Harmful algal blooms (HABs) pose an enormous threat to the U.S. marine habitation and economy in the coastal waters. Federal and state coastal administrators have been de- vising a state-of-the-art monitoring and forecasting system for these HAB events. The efficacy of a monitoring and forecasting system relies on the performance of HAB detection. We propose a machine learning based spatio-temporal

Balakrishna Gokaraju; Surya S. Durbha; Roger L. King; Nicolas H. Younan

2011-01-01

64

Temperature dependence of an estuarine harmful algal bloom: Resolving interannual variability in bloom dynamics using a degree day approach  

PubMed Central

Observations of harmful algal blooms (HABs) of the dinoflagellate Alexandrium fundyense in an estuary over multiple years were used to assess drivers of their spatial and temporal variability. Nauset Estuary on Cape Cod, Massachusetts has a recurrent, self-seeding A. fundyense population that produces paralytic shellfish poisoning toxins and leads to nearly annual closure to shellfishing. Weekly surveys of the entire estuary were made in 3 of 4 consecutive years, with surveys of a subembayment during the intervening year. Major A. fundyense blooms were observed all 4 years, with maximum concentrations >106 cells L?1. Concentrations were greatest in three salt ponds at the distal edges of the estuary. The bloom timing varied among the salt ponds and among years, although the blooms had similar durations and maximum cell concentrations. Nutrient concentrations did not correlate with the growth of the bloom, but differences in water temperature among years and ponds were significant. Net growth rates inferred from the surveys were similar to those from laboratory experiments, and increased linearly with temperature. A growing degree day calculation was used to account for effects of interannual variability and spatial gradients in water temperature on population development. The approach collapsed variability in the timing of bloom onset, development, and termination across years and among ponds, suggesting that this relatively simple metric could be used as an early-warning indicator for HABs in Nauset and similar areas with localized, self-seeding blooms. PMID:25419003

Ralston, David K.; Keafer, Bruce A.; Brosnahan, Michael L.; Anderson, Donald M.

2014-01-01

65

Fiber-Optic Microarray for Simultaneous Detection of Multiple Harmful Algal Bloom Species  

PubMed Central

Harmful algal blooms (HABs) are a serious threat to coastal resources, causing a variety of impacts on public health, regional economies, and ecosystems. Plankton analysis is a valuable component of many HAB monitoring and research programs, but the diversity of plankton poses a problem in discriminating toxic from nontoxic species using conventional detection methods. Here we describe a sensitive and specific sandwich hybridization assay that combines fiber-optic microarrays with oligonucleotide probes to detect and enumerate the HAB species Alexandrium fundyense, Alexandrium ostenfeldii, and Pseudo-nitzschia australis. Microarrays were prepared by loading oligonucleotide probe-coupled microspheres (diameter, 3 ?m) onto the distal ends of chemically etched imaging fiber bundles. Hybridization of target rRNA from HAB cells to immobilized probes on the microspheres was visualized using Cy3-labeled secondary probes in a sandwich-type assay format. We applied these microarrays to the detection and enumeration of HAB cells in both cultured and field samples. Our study demonstrated a detection limit of approximately 5 cells for all three target organisms within 45 min, without a separate amplification step, in both sample types. We also developed a multiplexed microarray to detect the three HAB species simultaneously, which successfully detected the target organisms, alone and in combination, without cross-reactivity. Our study suggests that fiber-optic microarrays can be used for rapid and sensitive detection and potential enumeration of HAB species in the environment. PMID:16957189

Ahn, Soohyoun; Kulis, David M.; Erdner, Deana L.; Anderson, Donald M.; Walt, David R.

2006-01-01

66

Fiber-optic microarray for simultaneous detection of multiple harmful algal bloom species.  

PubMed

Harmful algal blooms (HABs) are a serious threat to coastal resources, causing a variety of impacts on public health, regional economies, and ecosystems. Plankton analysis is a valuable component of many HAB monitoring and research programs, but the diversity of plankton poses a problem in discriminating toxic from nontoxic species using conventional detection methods. Here we describe a sensitive and specific sandwich hybridization assay that combines fiber-optic microarrays with oligonucleotide probes to detect and enumerate the HAB species Alexandrium fundyense, Alexandrium ostenfeldii, and Pseudo-nitzschia australis. Microarrays were prepared by loading oligonucleotide probe-coupled microspheres (diameter, 3 mum) onto the distal ends of chemically etched imaging fiber bundles. Hybridization of target rRNA from HAB cells to immobilized probes on the microspheres was visualized using Cy3-labeled secondary probes in a sandwich-type assay format. We applied these microarrays to the detection and enumeration of HAB cells in both cultured and field samples. Our study demonstrated a detection limit of approximately 5 cells for all three target organisms within 45 min, without a separate amplification step, in both sample types. We also developed a multiplexed microarray to detect the three HAB species simultaneously, which successfully detected the target organisms, alone and in combination, without cross-reactivity. Our study suggests that fiber-optic microarrays can be used for rapid and sensitive detection and potential enumeration of HAB species in the environment. PMID:16957189

Ahn, Soohyoun; Kulis, David M; Erdner, Deana L; Anderson, Donald M; Walt, David R

2006-09-01

67

Algal blooms in Ontario, Canada: Increases in reports since 1994  

Microsoft Academic Search

The Ontario Ministry of the Environment provides an algal identification service as part of the Ministry's response to algal bloom events, and we have been tracking the reports since 1994. From 1994 through 2009, we noted a significant increase in the number of algal blooms reported each year (P < 0.001). There was also an increase in the number of

Jennifer G. Winter; Anna M. DeSellas; Rachael Fletcher; Lucja Heintsch; Andrew Morley; Lynda Nakamoto; Kaoru Utsumi

2011-01-01

68

Patch recognition of algal blooms and macroalgae  

NASA Astrophysics Data System (ADS)

Fraunhofer lines and atmospheric absorption bands interfere with the spectral location of absorption bands of photosynthetic pigments in plankton. Hyperspectral data were used to address this interference on identifying absorption bands by applying derivative analysis of radiance spectra. Algal blooms show elevated radiance data even at longer wavelengths compared to oligotrophic water and may reach radiance values of around 800 W/m2/micrometer/sr at a wavelength of about 0.8 ?m. Therefore, the use of a spectral range beyond 0.55 ?m is useful to describe bloom characteristics. In particular, the slope between 0.55 ?m to 0.80 ?m shows an advantage to depict gradients in plankton blooms. Radiance spectra in the region from 0.4 to 0.8 ?m for oligotrophic water and near coastal water show similar location of absorption bands when analyzed with derivative analysis but with different amplitudes. For this reason, radiance spectra were also analyzed without atmospheric correction, and various approaches to interpret radiance data over plankton blooms were investigated. Cluster analysis and ratio techniques at longer wavelengths were found to assist in the separation of ocean color gradients and distinguish bio-geochemical provinces in near-coastal waters. Furthermore, using the slope of spectra from plankton blooms, in connection with scatter diagrams at various wavelengths, shows that details can be revealed that would not be recognized in single channels at lower wavelength.

Szekielda, K. H.; Bowles, J. H.; Gillis, D. B.; Snyder, W.; Miller, W. D.

2010-04-01

69

Hindcasts of potential harmful algal bloom transport pathways on the Pacific Northwest coast  

NASA Astrophysics Data System (ADS)

algal blooms (HABs) pose a significant threat to human and marine organism health, and negatively impact coastal economies around the world. An improved understanding of HAB formation and transport is required to improve forecasting skill. A realistic numerical simulation of the US Pacific Northwest region is used to investigate transport pathways from known HAB formation hot spots, specifically for Pseudo-nitzschia (Pn), to the coast. We show that transport pathways are seasonal, with transport to the Washington (WA) coast from a northern source (the Juan de Fuca Eddy) during the summer/fall upwelling season and from a southern source (Heceta Bank) during the winter/early spring due to the predominant wind-driven currents. Interannual variability in transport from the northern source is related to the degree of wind intermittency with more transport during years with more frequent relaxation/downwelling events. The Columbia River plume acts to mitigate transport to the coast as the plume front blocks onshore transport. The plume's influence on alongshore transport is variable although critical in aiding transport from the southern source to the WA coast via plume entrainment. Overall transport from our simulations captures most observed Pn HAB beach events from 2004 to 2007 (characterized by Pseudo-nitzschia cell abundance); however, numerous false positives occur. We show that incorporating phytoplankton biomass results from a coupled biogeochemical model reduces the number of false positives significantly and thus improves our Pn HAB predictions.

Giddings, S. N.; MacCready, P.; Hickey, B. M.; Banas, N. S.; Davis, K. A.; Siedlecki, S. A.; Trainer, V. L.; Kudela, R. M.; Pelland, N. A.; Connolly, T. P.

2014-04-01

70

Applications of Satellite Ocean Color Imagery for Detecting and Monitoring Harmful Algal Blooms in the Olympic Peninsula Region  

SciTech Connect

Harmful algal blooms (HABs) attributed to Pseudo-nitzschia species, a diatom that produces Domoic acid, are a common occurrence and serious threat along the coast of the US Northwest. Monitoring these events or providing advanced warning of their occurrence at the coast would provide an important aid to fisheries managers. Remote sensing, which is being used in the Gulf of Mexico for HAB detection and forecasting (of a different algae), could provide a tool for monitoring and warnings. Chlorophyll and SST imagery are being used to support a research and monitoring program for the region, and HAB monitoring techniques used in the Gulf of Mexico are being examined for their potential utility along the Washington coast. The focus of this study is to determine the efficacy of using satellite ocean color imagery for HAB monitoring off of Washingtons Olympic Peninsula region, and to provide support in the form of ocean color imagery products for management and mitigation efforts.

Holt, Ashley C.; Stumpf, Richard P.; Tomlinson, Michelle C.; Ransibrahmanakul, Varis; Trainer, Vera L.; Woodruff, Dana L.

2003-08-01

71

Help! It's an HAB!  

NSDL National Science Digital Library

These web activities are part of a series of lessons that provide information and materials to teach students about the effects of harmful algal blooms (HABs) on fish as well as devising remediation techniques. It features web links to other related lessons and pages as well as a chart of education standards met by these activities by grade level.

Bigelow Laboratory

72

Detection of harmful algal bloom causing microalgae using covalently immobilised capture oligonucleotide probes on glass and poly(dimethylsiloxane) surfaces  

NASA Astrophysics Data System (ADS)

Harmful algal bloom (HAB) events have been on the rise in the last few decades with some of the causative microalgae exhibiting toxic properties. Therefore, detection is essential in order to prevent mortality of aquatic life and poisoning events from consumption of these biotoxins. Here, oligonucleotide modified glass and poly(dimethylsiloxane) (PDMS) surfaces have been developed for the detection of the HAB causing microalgae, Alexandrium catenella, in a model system. Our preliminary studies show that the glass surface offers superior stability and analytical response when compared to those prepared from PDMS.

Bruce, Karen L.; Ellis, Amanda V.; Leterme, Sophie C.; Khodakov, Dmitriy A.; Lenehan, Claire E.

2013-12-01

73

DETECTING HARMFUL ALGAL BLOOMS IN LOUISIANA COASTAL WATERS -  

EPA Science Inventory

This project will do in situ monitoring of HABs, that coupled with ongoing water quality monitoring, will provide useful cause and effect information about the occurrence and locations of blooms within the area. In the Lake Salvadore area of the Barataria Bay, just southwest of N...

74

Impact of harmful algal blooms on wild and cultured animals in the Gulf of California.  

PubMed

Historical documents and classic works together with recent specialized literature have described Harmful Algal Blooms (HABs) in the Gulf of California. This is a review of HABs impact (qualitative and quantitative) during the last decades in the Gulf of California on wild (mammals, birds, fishes, and invertebrates) and cultured animals (shrimps and fishes). Microalgal species responsible of noxious effects are Noctiluca scintillans, Cochlodinium polykrikoides, Gymnodinium catenatum, Prorocentrum minimum, Akashiwo sanguinea, Chattonella subsalsa Ch. marina, Chattonella sp., Heterocapsa sp., Dinophysis sp., Fibrocapsa japonica, Heterosigma akashiwo, Thalassiosira sp., Chaetoceros spp., Pseudo-nitzschia australis, P fraudulenta, Pseudo-nitzschia sp., Trichodesmium erythraeum and ScSchizotrix calcicola. Emphasis is given to the necessity to continue with interdisciplinary studies in oceanography, ecology, toxicology and toxinology interrelated with biomedical sciences such as physiology, pathology, epidemiology and animal health. PMID:22315821

Núñez Vázquez, Erick J; Lizarraga, Ismael Gárate; Schmidt, Christine J Band; Tapia, Amaury Cordero; Cortes, David J Lopez; Sandoval, Francisco E Hernandez; Tapia, Alejandra Heredia; Guzman, Jose J Bustillos

2011-07-01

75

Solutions Network Formulation Report. Integrating Salinity Measurements from Aquarius into the Harmful Algal Blooms Observing System  

NASA Technical Reports Server (NTRS)

This Candidate Solution suggests the use of Aquarius sea surface salinity measurements to improve the NOAA/NCDDC (National Oceanic and Atmospheric Administration s National Coastal Data Development Center) HABSOS (Harmful Algal Blooms Observing System) DST (decision support tool) by enhancing development and movement forecasts of HAB events as well as potential species identification. In the proposed configuration, recurring salinity measurements from the Aquarius mission would augment HABSOS sea surface temperature and in situ ocean current measurements. Thermohaline circulation observations combined with in situ measurements increase the precision of HAB event movement forecasting. These forecasts allow coastal managers and public health officials to make more accurate and timely warnings to the public and to better direct science teams to event sites for collection and further measurements.

Anderson, Daniel; Lewis, David; Hilbert, Kent

2007-01-01

76

Airborne Monitoring of Harmful Algal Blooms over Lake Erie  

NASA Technical Reports Server (NTRS)

The Hyperspectral Imager mounted to an aircraft was used to develop a remote sensing capability to detect the pigment Phycocyanin, an indicator of Microcystis, in low concentration as an early indicator of harmful algal bloom prediction.

Tokars, Roger; Lekki, John

2013-01-01

77

Toxic Algal Blooms in a Changing Coastal Ocean  

E-print Network

warming Royal Society, 2005 How will global change affect harmful algal blooms and toxin production? #12 2011, Mendocino county, CA Gonyaulax spinifera #12;Ocean acidification Global;Warming favors dinoflagellate blooms Cloern et al. 2005, GRL 32 #12;Dinoflagellate range extensions

Rohs, Remo

78

What is causing the harmful algal blooms in Lake Erie?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Harmful and nuisance algal blooms have been increasing in size and extent since about 2000. In recent years, the release of the algal toxin microcystin has become a growing concern and has resulted in the inability to use water from Lake Erie as a drinking water source to the 400,000 residents of T...

79

Lack of variation in voltage-gated sodium channels of common bottlenose dolphins (Tursiops truncatus) exposed to neurotoxic algal blooms.  

PubMed

In coastal marine ecosystems, neurotoxins produced by harmful algal blooms (HABs) often result in large-scale mortality events of many marine species. Historical and frequent exposure to HABs therefore may provide a strong selective pressure for adaptations that result in toxin resistance. Neurotoxin resistance has independently evolved in a variety of terrestrial and marine species via mutations in genes encoding the toxin binding sites within the voltage-gated sodium channel gene complex. Accordingly, we tested the hypothesis that genetic variation in the putative binding site of brevetoxins in common bottlenose dolphins (Tursiops truncatus) explains differences among individuals or populations in resistance to harmful Karenia brevis blooms in the Gulf of Mexico. We found very little variation in the sodium channel exons encoding the putative brevetoxin binding site among bottlenose dolphins from central-west Florida and the Florida Panhandle. Our study included samples from several bottlenose dolphin mortality events associated with HABs, but we found no association between genetic variation and survival. We observed a significant effect of geographic region on genetic variation for some sodium channel isoforms, but this can be primarily explained by rare private alleles and is more likely a reflection of regional genetic differentiation than the cause of different levels of HAB resistance between regions. In contrast to many other previously studied neurotoxin-resistant species, we conclude that bottlenose dolphins have not evolved resistance to HABs via mutations in genes encoding the brevetoxin binding site on the voltage-gated sodium channels. PMID:25456229

Cammen, Kristina M; Rosel, Patricia E; Wells, Randall S; Read, Andrew J

2014-12-01

80

December 2011 NATIONAL HARMFUL ALGAL BLOOM (HAB) FORECAST SYSTEM  

E-print Network

). · Weekly model prediction and model/observation comparison issued beginning in April or sooner if there dynamics data · Remote sensing sea surface temperature data (NOAA CoastWatch) · In situ data (NERACOOS, Eco forecast products: · In situ optical data from moored/motion sensors (ESP data reported by WHOI) · Public

81

The effects of harmful algal species and food concentration on zooplankton grazer production of dissolved organic matter and inorganic nutrients  

Microsoft Academic Search

Harmful algal blooms (HABs), including toxic species, have been increasing in frequency, range, and duration over the past several decades. The effect of a harmful or toxic algal diet on zooplankton nutrient regeneration, however, has not been previously examined. In this study, we determined the effects of non-bloom and bloom concentrations of non-toxic and toxic cultures of HAB species Prorocentrum

Grace K. Saba; Deborah K. Steinberg; Deborah A. Bronk

2011-01-01

82

Harmful Algal Blooms: Neurotoxic Shellfish Poisoning  

NSDL National Science Digital Library

This University of Maryland SeaGrant web page discusses the toxic dinoflagellate Gymnodinium breve and its role in red tide blooms and Neurotoxic Shellfish Poisoning (NSP). The page explores the economic, ecological, and health-related effects of red tide blooms, and the causative accumulation of G. breve into blooms that produce the powerful neurotoxins known as brevetoxins.

Kane, Andrew; Jacobs, Dan; The Aquatic Pathobiology Center, University of Maryland; Maryland SeaGrant

83

HARMFUL ALGAL BLOOMS OBSERVING SYSTEM PILOT PROJECT  

EPA Science Inventory

The HABSOS Pilot Project is being developed through a partnership of federal, state and academic organizations as proof-of-concept for a coastal observing system in the Gulf of Mexico. The goal is to design a HAB data management system and develop the regional communication infra...

84

Impacts of climate variability and future climate change on harmful algal blooms and human health  

PubMed Central

Anthropogenically-derived increases in atmospheric greenhouse gas concentrations have been implicated in recent climate change, and are projected to substantially impact the climate on a global scale in the future. For marine and freshwater systems, increasing concentrations of greenhouse gases are expected to increase surface temperatures, lower pH, and cause changes to vertical mixing, upwelling, precipitation, and evaporation patterns. The potential consequences of these changes for harmful algal blooms (HABs) have received relatively little attention and are not well understood. Given the apparent increase in HABs around the world and the potential for greater problems as a result of climate change and ocean acidification, substantial research is needed to evaluate the direct and indirect associations between HABs, climate change, ocean acidification, and human health. This research will require a multidisciplinary approach utilizing expertise in climatology, oceanography, biology, epidemiology, and other disciplines. We review the interactions between selected patterns of large-scale climate variability and climate change, oceanic conditions, and harmful algae. PMID:19025675

Moore, Stephanie K; Trainer, Vera L; Mantua, Nathan J; Parker, Micaela S; Laws, Edward A; Backer, Lorraine C; Fleming, Lora E

2008-01-01

85

Vulnerability of coastal ecosystems to changes in harmful algal bloom distribution in response to climate change: projections based on model analysis.  

PubMed

Harmful algal blooms (HABs), those proliferations of algae that can cause fish kills, contaminate seafood with toxins, form unsightly scums, or detrimentally alter ecosystem function have been increasing in frequency, magnitude, and duration worldwide. Here, using a global modeling approach, we show, for three regions of the globe, the potential effects of nutrient loading and climate change for two HAB genera, pelagic Prorocentrum and Karenia, each with differing physiological characteristics for growth. The projections (end of century, 2090-2100) are based on climate change resulting from the A1B scenario of the Intergovernmental Panel on Climate Change Institut Pierre Simon Laplace Climate Model (IPCC, IPSL-CM4), applied in a coupled oceanographic-biogeochemical model, combined with a suite of assumed physiological 'rules' for genera-specific bloom development. Based on these models, an expansion in area and/or number of months annually conducive to development of these HABs along the NW European Shelf-Baltic Sea system and NE Asia was projected for both HAB genera, but no expansion (Prorocentrum spp.), or actual contraction in area and months conducive for blooms (Karenia spp.), was projected in the SE Asian domain. The implications of these projections, especially for Northern Europe, are shifts in vulnerability of coastal systems to HAB events, increased regional HAB impacts to aquaculture, increased risks to human health and ecosystems, and economic consequences of these events due to losses to fisheries and ecosystem services. PMID:24942916

Glibert, Patricia M; Icarus Allen, J; Artioli, Yuri; Beusen, Arthur; Bouwman, Lex; Harle, James; Holmes, Robert; Holt, Jason

2014-12-01

86

ECOSYSTEM EFFECTS OF CYANOBACTERIAL HARMFUL ALGAL BLOOMS  

EPA Science Inventory

Harmful cyanobacterial blooms represent one of the most serious ecological stressors in lakes, rivers, estuaries and marine environments. When there are persistent or frequent blooms with high biomass of cyanobacterial cells, colonies or filaments in the water, a wide range of i...

87

A universal method for flocculating harmful algal blooms in marine and fresh waters using modified sand.  

PubMed

A universal environmental friendly method was developed to turn sand into effective flocculants for mitigating harmful algal blooms (HABs) in marine and freshwater systems. The isoelectric point of sand was largely increased from pH 4.5 to 10.5 after been modified by Moringa oleifera coagulant (MO) abstracted form MO seeds. However, when sand was modified by MO alone, maximum removal efficiencies of 80% and 20% for Amphidinium carterae (A.C.) and Chlorella sp. (C.S.) in seawater and 60% for Microcystis aeruginosa (M.A.) in fresh water were achieved in 30 min. The limited removal improvement was due to the form of only small flocs (20-100 ?m) by surface charge modification only. Large flocs (270-800 ?m) and high removal rate of 96% A.C. and C.S. cells in seawater and 90% of M.A. cells in fresh water were achieved within 30 min when the small MO-algae-sand flocs were linked and bridged by chitosan. High HAB removal rate is achievable when the sand is modified by the bicomponent mechanism of surface charge and netting-bridging modification using biodegradable modifiers such as MO and chitosan. The optimized dosage of modified sand depends on the property of algal cells and water conditions. PMID:23611410

Li, Liang; Pan, Gang

2013-05-01

88

Harmful Cyanobacterial Blooms  

Microsoft Academic Search

Harmful algal blooms (HABs) are frequently reported in many countries around the world. Even though this phenomenon has been\\u000a known for a long time1, the causes of HABs and toxicity releases are still not understood. Effective management of HABs of\\u000a cyanobacteria requires an understanding of both the environmental factors associated with their formation and the effectiveness\\u000a of available management alternatives

Igor Linkov; A. Fristachi; F. K. Satterstrom; A. Shifrin; J. Steevens; G. A. Clyde Jr; G. Rice

89

Cephalopods as vectors of harmful algal bloom toxins in marine food webs.  

PubMed

Here we summarize the current knowledge on the transfer and accumulation of harmful algal bloom (HAB)-related toxins in cephalopods (octopods, cuttlefishes and squids). These mollusks have been reported to accumulate several HAB-toxins, namely domoic acid (DA, and its isomers), saxitoxin (and its derivatives) and palytoxin (and palytoxin-like compounds) and, therefore, act as HAB-toxin vectors in marine food webs. Coastal octopods and cuttlefishes store considerably high levels of DA (amnesic shellfish toxin) in several tissues, but mainly in the digestive gland (DG)--the primary site of digestive absorption and intracellular digestion. Studies on the sub-cellular partitioning of DA in the soluble and insoluble fractions showed that nearly all DA (92.6%) is found in the cytosol. This favors the trophic transfer of the toxins since cytosolic substances can be absorbed by predators with greater efficiency. The available information on the accumulation and tissue distribution of DA in squids (e.g., in stranded Humboldt squids, Dosidicus gigas) is scarcer than in other cephalopod groups. Regarding paralytic shellfish toxins (PSTs), these organisms accumulate them at the greatest extent in DG > kidneys > stomach > branchial hearts > posterior salivary glands > gills. Palytoxins are among the most toxic molecules identified and stranded octopods revealed high contamination levels, with ovatoxin (a palytoxin analogue) reaching 971 ?g kg?¹ and palytoxin reaching 115 ?g kg?¹ (the regulatory limit for PlTXs is 30 ?g kg?¹ in shellfish). Although the impacts of HAB-toxins in cephalopod physiology are not as well understood as in fish species, similar effects are expected since they possess a complex nervous system and highly developed brain comparable to that of the vertebrates. Compared to bivalves, cephalopods represent a lower risk of shellfish poisoning in humans, since they are usually consumed eviscerated, with exception of traditional dishes from the Mediterranean area. PMID:24018900

Lopes, Vanessa M; Lopes, Ana Rita; Costa, Pedro; Rosa, Rui

2013-09-01

90

Cephalopods as Vectors of Harmful Algal Bloom Toxins in Marine Food Webs  

PubMed Central

Here we summarize the current knowledge on the transfer and accumulation of harmful algal bloom (HAB)-related toxins in cephalopods (octopods, cuttlefishes and squids). These mollusks have been reported to accumulate several HAB-toxins, namely domoic acid (DA, and its isomers), saxitoxin (and its derivatives) and palytoxin (and palytoxin-like compounds) and, therefore, act as HAB-toxin vectors in marine food webs. Coastal octopods and cuttlefishes store considerably high levels of DA (amnesic shellfish toxin) in several tissues, but mainly in the digestive gland (DG)—the primary site of digestive absorption and intracellular digestion. Studies on the sub-cellular partitioning of DA in the soluble and insoluble fractions showed that nearly all DA (92.6%) is found in the cytosol. This favors the trophic transfer of the toxins since cytosolic substances can be absorbed by predators with greater efficiency. The available information on the accumulation and tissue distribution of DA in squids (e.g., in stranded Humboldt squids, Dosidicus gigas) is scarcer than in other cephalopod groups. Regarding paralytic shellfish toxins (PSTs), these organisms accumulate them at the greatest extent in DG >> kidneys > stomach > branchial hearts > posterior salivary glands > gills. Palytoxins are among the most toxic molecules identified and stranded octopods revealed high contamination levels, with ovatoxin (a palytoxin analogue) reaching 971 ?g kg?1 and palytoxin reaching 115 ?g kg?1 (the regulatory limit for PlTXs is 30 ?g kg?1 in shellfish). Although the impacts of HAB-toxins in cephalopod physiology are not as well understood as in fish species, similar effects are expected since they possess a complex nervous system and highly developed brain comparable to that of the vertebrates. Compared to bivalves, cephalopods represent a lower risk of shellfish poisoning in humans, since they are usually consumed eviscerated, with exception of traditional dishes from the Mediterranean area. PMID:24018900

Lopes, Vanessa M.; Lopes, Ana Rita; Costa, Pedro; Rosa, Rui

2013-01-01

91

Authentication of the proteins expression profiles (PEPs) identification methodology in a bloom of Karenia digitata, the most damaging harmful algal bloom causative agent in the history of Hong Kong  

Microsoft Academic Search

Identification of harmful algal bloom (HAB) causative agents makes use either of morphology-based techniques or genetic tools. These techniques are often time-consuming, labor intensive, and\\/or based on subjective judgment. Recently, matching with protein\\/peptide expression profiles (PEPs) obtained with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI–TOF–MS) has emerged as a new technique for species identification of various microorganisms. We were

Fred Wang-Fat Lee; Kin-Chung Ho; Yun-Lam Mak; Samuel Chun-Lap Lo

92

Satellite remote sensing of harmful algal blooms: A new multi-algorithm method for detecting the Florida Red Tide (Karenia brevis)  

PubMed Central

In a continuing effort to develop suitable methods for the surveillance of Harmful Algal Blooms (HABs) of Karenia brevis using satellite radiometers, a new multi-algorithm method was developed to explore whether improvements in the remote sensing detection of the Florida Red Tide was possible. A Hybrid Scheme was introduced that sequentially applies the optimized versions of two pre-existing satellite-based algorithms: an Empirical Approach (using water-leaving radiance as a function of chlorophyll concentration) and a Bio-optical Technique (using particulate backscatter along with chlorophyll concentration). The long-term evaluation of the new multi-algorithm method was performed using a multi-year MODIS dataset (2002 to 2006; during the boreal Summer-Fall periods – July to December) along the Central West Florida Shelf between 25.75°N and 28.25°N. Algorithm validation was done with in situ measurements of the abundances of K. brevis; cell counts ?1.5×104 cells l?1 defined a detectable HAB. Encouraging statistical results were derived when either or both algorithms correctly flagged known samples. The majority of the valid match-ups were correctly identified (~80% of both HABs and non-blooming conditions) and few false negatives or false positives were produced (~20% of each). Additionally, most of the HAB-positive identifications in the satellite data were indeed HAB samples (positive predictive value: ~70%) and those classified as HAB-negative were almost all non-bloom cases (negative predictive value: ~86%). These results demonstrate an excellent detection capability, on average ~10% more accurate than the individual algorithms used separately. Thus, the new Hybrid Scheme could become a powerful tool for environmental monitoring of K. brevis blooms, with valuable consequences including leading to the more rapid and efficient use of ships to make in situ measurements of HABs. PMID:21037979

Carvalho, Gustavo A.; Minnett, Peter J.; Fleming, Lora E.; Banzon, Viva F.; Baringer, Warner

2010-01-01

93

Fish Sound Production in the Presence of Harmful Algal Blooms in the Eastern Gulf of Mexico  

PubMed Central

This paper presents the first known research to examine sound production by fishes during harmful algal blooms (HABs). Most fish sound production is species-specific and repetitive, enabling passive acoustic monitoring to identify the distribution and behavior of soniferous species. Autonomous gliders that collect passive acoustic data and environmental data concurrently can be used to establish the oceanographic conditions surrounding sound-producing organisms. Three passive acoustic glider missions were conducted off west-central Florida in October 2011, and September and October 2012. The deployment period for two missions was dictated by the presence of red tide events with the glider path specifically set to encounter toxic Karenia brevis blooms (a.k.a red tides). Oceanographic conditions measured by the glider were significantly correlated to the variation in sounds from six known or suspected species of fish across the three missions with depth consistently being the most significant factor. At the time and space scales of this study, there was no detectable effect of red tide on sound production. Sounds were still recorded within red tide-affected waters from species with overlapping depth ranges. These results suggest that the fishes studied here did not alter their sound production nor migrate out of red tide-affected areas. Although these results are preliminary because of the limited measurements, the data and methods presented here provide a proof of principle and could serve as protocol for future studies on the effects of algal blooms on the behavior of soniferous fishes. To fully capture the effects of episodic events, we suggest that stationary or vertically profiling acoustic recorders and environmental sampling be used as a complement to glider measurements. PMID:25551564

Wall, Carrie C.; Lembke, Chad; Hu, Chuanmin; Mann, David A.

2014-01-01

94

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers  

USGS Publications Warehouse

In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large "blooms" in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers. Copyright 2011 by the American Geophysical Union.

Sundareshwar, P.V.; Upadhayay, S.; Abessa, M.; Honomichl, S.; Berdanier, B.; Spaulding, S.A.; Sandvik, C.; Trennepohl, A.

2011-01-01

95

From genome-wide to candidate gene: an investigation of variation at the major histocompatibility complex in common bottlenose dolphins exposed to harmful algal blooms.  

PubMed

The role the major histocompatibility complex (MHC) plays in response to exposure to environmental toxins is relatively poorly understood, particularly in comparison to its well-described role in pathogen immunity. We investigated associations between MHC diversity and resistance to brevetoxins in common bottlenose dolphins (Tursiops truncatus). A previous genome-wide association study investigating an apparent difference in harmful algal bloom (HAB) resistance among dolphin populations in the Gulf of Mexico identified genetic variation associated with survival in close genomic proximity to multiple MHC class II loci. Here, we characterized genetic variation at DQA, DQB, DRA, and DRB loci in dolphins from central-west Florida and the Florida Panhandle, including dolphins that died during HABs and dolphins presumed to have survived HAB exposure. We found that DRB and DQB exhibited patterns of genetic differentiation among geographic regions that differed from neutral microsatellite loci. In addition, genetic differentiation at DRB across multiple pairwise comparisons of live and dead dolphins was greater than differentiation observed at neutral loci. Our findings at these MHC loci did not approach the strength of association with survival previously described for a nearby genetic variant. However, the results provide evidence that selective pressures at the MHC vary among dolphin populations that differ in the frequency of HAB exposure and that the overall composition of DRB variants differs between dolphin survivors and non-survivors of HABs. These results may suggest a potential role of MHC diversity in variable survival of bottlenose dolphins exposed to HABs. PMID:25475909

Cammen, Kristina M; Wilcox, Lynsey A; Rosel, Patricia E; Wells, Randall S; Read, Andrew J

2015-02-01

96

Molecular detection and species identification of Alexandrium (Dinophyceae) causing harmful algal blooms along the Chilean coastline  

PubMed Central

Background and aims On the basis of morphological evidence, the species involved in South American Pacific coast harmful algal blooms (HABs) has been traditionally recognized as Alexandrium catenella (Dinophyceae). However, these observations have not been confirmed using evidence based on genomic sequence variability. Our principal objective was to accurately determine the species of Alexandrium involved in local HABs in order to implement a real-time polymerase chain reaction (PCR) assay for its rapid and easy detection on filter-feeding shellfish, such as mussels. Methodology For species-specific determination, the intergenic spacer 1 (ITS1), 5.8S subunit, ITS2 and the hypervariable genomic regions D1–D5 of the large ribosomal subunit of local strains were sequenced and compared with two data sets of other Alexandrium sequences. Species-specific primers were used to amplify signature sequences within the genomic DNA of the studied species by conventional and real-time PCR. Principal results Phylogenetic analysis determined that the Chilean strain falls into Group I of the tamarensis complex. Our results support the allocation of the Chilean Alexandrium species as a toxic Alexandrium tamarense rather than A. catenella, as currently defined. Once local species were determined to belong to Group I of the tamarensis complex, a highly sensitive and accurate real-time PCR procedure was developed to detect dinoflagellate presence in Mytilus spp. (Bivalvia) samples after being fed (challenged) in vitro with the Chilean Alexandrium strain. The results show that real-time PCR is useful to detect Alexandrium intake in filter-feeding molluscs. Conclusions It has been shown that the classification of local Alexandrium using morphological evidence is not very accurate. Molecular methods enabled the HAB dinoflagellate species of the Chilean coast to be assigned as A. tamarense rather than A. catenella. Real-time PCR analysis based on A. tamarense primers allowed the detection of dinoflagellate DNA in Mytilus spp. samples exposed to this alga. Through the specific assignment of dinoflagellate species involved in HABs, more reliable preventive policies can be implemented. PMID:23259043

Jedlicki, Ana; Fernández, Gonzalo; Astorga, Marcela; Oyarzún, Pablo; Toro, Jorge E.; Navarro, Jorge M.; Martínez, Víctor

2012-01-01

97

ARS Research on Harmful Algal Blooms in SE USA Aquaculture Impoundments  

Technology Transfer Automated Retrieval System (TEKTRAN)

As part of an EPA sponsored state of knowledge symposium on toxic cyanobacteria, six workgroups were established to assess published literature. A review of ARS research on harmful algal blooms was made by the incumbent. Aquaculture systems have had four types of freshwater toxic algal blooms. De...

98

HEALTH AND ECOLOGICAL IMPACTS OF HARMFUL ALGAL BLOOMS: RISK ASSESSMENT NEEDS  

EPA Science Inventory

The symposium session, Indicators for Effects and Predictions of Harmful Algal Blooms, explored the current state of indicators used to assess the human health and ecological risks caused by harmful algal blooms, and highlighted future needs and impediments that must be overcome...

99

Record-setting algal bloom in Lake Erie caused by agricultural and meteorological trends consistent with  

E-print Network

Verhammei , David M. Wrightd , and Melissa A. Zagorskid a Department of Global Ecology, Carnegie Institution) In 2011, Lake Erie experienced the largest harmful algal bloom in its recorded history, with a peak the bloom, and warm and quiescent conditions after bloom onset allowed algae to remain near the top

100

Harmful Algal Blooms of the West Florida Shelf and Campeche Bank: Visualization and Quantification using Remote Sensing Methods  

NASA Astrophysics Data System (ADS)

Harmful Algal Blooms (HABs) in the Gulf of Mexico (GOM) are natural phenomena that can have negative impacts on marine ecosystems on which human health and the economy of some Gulf States depends. Many of the HABs in the GOM are dominated by the toxic dinoflagellate Karenia brevis. Non-toxic phytoplankton taxa such as Scrippsiella sp. also form intense blooms off the Mexican coast that result in massive fish mortality and economic losses, particularly as they may lead to anoxia. The main objectives of this dissertation were to (1) evaluate and improve the techniques developed for detection of Karenia spp. blooms on the West Florida Shelf (WFS) using satellite remote sensing methods, (2) test the use of these methods for waters in the GOM, and (3) use the output of these techniques to better understand the dynamics and evolution of Karenia spp. blooms in the WFS and off Mexico. The first chapter of this dissertation examines the performance of several Karenia HABs detection techniques using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images and historical ground truth observations collected on the WFS from August 2002 to December 2011. A total of 2323 in situ samples collected by the Florida Fish and Wildlife Research Institute to test for Karenia spp. matched pixels with valid ocean color satellite observations over this period. This dataset was used to systematically optimize variables and coefficients used in five published HAB detection methods. Each technique was tested using a set of metrics that included the F-Measure (FM). Before optimization, the average FM for all techniques was 0.47. After optimization, the average FM increased to 0.59, and false positives decreased ~50%. The addition of a Fluorescence Line Height (FLH) criterion improved the performance of every method. A new practical method was developed using a combination of FLH and Remote Sensing Reflectance at 555 nm (Rrs555-FLH). The new method resulted in an FM of 0.62 and 3% false negatives, similar to those from more complex techniques. The first chapter concludes with a series of recommendations on how to improve the detection techniques and how to take these results a step further into a Gulf wide observing systems for HABs. In chapter two, ocean color techniques were used to examine the extension, evolution and displacement of four Karenia spp. events that occurred in the WFS between 2004 and 2011. Blooms were identified in the imagery using the new Rrs-FLH method and validated using in situ phytoplankton cell counts. The spatial extension of each event was followed in time by delineating the blooms. In 2004 and 2005, the WFS was affected by a series of hurricanes that led to high river discharge and intense sediment resuspension events. Both processes had an impact on HAB occurrence. For example, I tracked a Karenia spp. bloom found in late December 2004 approximately 40-80 km offshore Saint Petersburg, which then expanded reaching an extension of >8000 km2 in February 2005. The bloom weakened in spring 2005 and intensified again in summer reaching >42,000 km 2 after the passage of hurricane Katrina in August 2005. This bloom covered the WFS from Charlotte Harbor to the Florida Panhandle. Two other cases were studied in the WFS. The results of the Hybrid Coordinate Ocean Model from the U.S. Navy aid understanding the dispersal of the blooms. During fall 2011, three field campaigns to study HABs in Mexico were conducted to do an analysis of optical properties and explore the possibility of using ocean color techniques to distinguish between the main phytoplankton blooms in that region. Three main bloom scenarios were observed in the Campeche Bank region: massive diatom blooms, blooms dominated by Scrippsiella spp., and Karenia spp. blooms. The normalized specific phytoplankton absorption spectra were found to be different for Karenia spp. and Scrippsiella sp. blooms. A new technique that combines phytoplankton absorption derived from MODIS data and the new technique developed in Chapter One showed potential for a detect

Soto Ramos, Inia Mariel

101

The ability of the branchiopod, Artemia salina, to graze upon harmful algal blooms caused by Alexandrium fundyense, Aureococcus anophagefferens, and Cochlodinium polykrikoides  

NASA Astrophysics Data System (ADS)

We present experiments that examined the grazing and survivorship of zooplankton native (Acartia tonsa) and non-native (Artemia salina) to NY (USA) estuaries when exposed to blooms and cultures of the three harmful algae native to NY, Alexandrium fundyense, Aureococcus anophagefferens (strains CCMP 1850 and CCMP 1984) and Cochlodinium polykrikoides. During experiments with cultures of A. anophagefferens, clearance rates (CR) of A. salina were significantly greater than those of A. tonsa for both algal strains examined. A. salina fed on cultures of C. polykrikoides at higher rates than all phytoplankton species examined, including the control diet (Rhodomonas salina), and faster than rates of A. tonsa fed C. polykrikoides. During experiments with A. fundyense, A. salina actively grazed all cell concentrations (250-1500 cells ml-1) while A. tonsa did not feed at any concentration. Percent mortality of A. salina and A. tonsa fed A. fundyense for 48 h were 43 ± 7.7% and 72 ± 7.8%, respectively, percentages significantly higher than those of individuals fed all other algal diets. During 25 field experiments using natural blooms of the three HAB species performed across six NY estuaries, A. salina significantly (p < 0.05) reduced cell densities of A. anophagefferens, C. polykrikoides, and A. fundyense relative to the control treatments in all but one experiment. The sum of these findings demonstrates that a failure to graze these HABs by the indigenous copepod, A. tonsa, may permit blooms to occur. In addition, the ability of A. salina to graze these HABs at densities that were inhibitory to A. tonsa suggests that A. salina could, in some circumstances, be considered as a part of mitigation strategy for these events.

Marcoval, M. Alejandra; Pan, Jerónimo; Tang, Yingzhong; Gobler, Christopher J.

2013-10-01

102

Dynamic bacterial and viral response to an algal bloom at subzero temperatures  

Microsoft Academic Search

New evidence suggests that cold-loving (psychrophilic) bacteria may be a dynamic component of the episodic bloom events of high-latitude ecosystems. Here we report the results of an unusually early springtime study of pelagic microbial activity in the coastal Alaskan Arctic. Heterotrophic bacterioplankton clearly responded to an algal bloom by doubling cell size, increasing the fraction of actively respiring cells (up

Patricia L. Yager; Tara L. Connelly; Behzad Mortazavi; K. Eric Wommack; Nasreen Bano; James E. Bauer; Stephen Opsahl; James T. Hollibaugh

2001-01-01

103

National Oceanic and Atmospheric Administration (NOAA) Harmful Algal Bloom Bulletin Home Page  

NSDL National Science Digital Library

This webpage provides access to weekly Harmful Algal Bloom bulletins that are generated for the Gulf of Mexico by the NOAA Coastwatch Program, the National Ocean Service and the National Environmental Satellite Data and Information Service. These bulletins provide notification of bloom conditions to state and local coastal managers in the Gulf of Mexico and include maps with information on wind conditions, chlorophyll levels, and potential or actual bloom events.

2010-02-08

104

National Oceanic and Atmospheric Administration (NOAA) Harmful Algal Bloom Bulletin Home Page  

NSDL National Science Digital Library

This webpage provides access to weekly Harmful Algal Bloom bulletins that are generated for the Gulf of Mexico by the NOAA Coastwatch Program, the National Ocean Service and the National Environmental Satellite Data and Information Service. These bulletins provide notification of bloom conditions to state and local coastal managers in the Gulf of Mexico and include maps with information on wind conditions, chlorophyll levels, and potential or actual bloom events.

Administration, The N.

105

Role of gas vesicles and intra-colony spaces during the process of algal bloom formation.  

PubMed

Aggregation morphology, vertical distribution, and algal density were analyzed during the algal cell floating process in three environments. The role of gas vesicles and intra-colony spaces was distinguished by algal blooms treated with ultrasonic waves and high pressure. Results demonstrated that the two buoyancy providers jointly provide buoyancy for floating algal cells. The results were also confirmed by force analysis. In the simulation experiment, the buoyancy acting on algal cells was greater than its gravity at sample ports 2 and 3 of a columnar-cultivated cell vessel, and intra-colony spaces were not detected. In Taihu Lake, gas vesicle buoyancy was notably less than total algal cell gravity. Buoyancy provided by intra-colony spaces exceeded total algal cell gravity at the water surface, but not at other water depths. In the Daning River, total buoyancies provided by the two buoyancy providers were less than total algal cell gravity at different water depths. PMID:23833817

Zhang, Yongsheng; Zheng, Binghui; Jiang, Xia; Zheng, Hao

2013-06-01

106

[Systematic investigation into winter and spring algal blooms in Daning River of Three Gorges Reservoir].  

PubMed

According to the survey conducted from winter and spring algal blooms, the changes of water quality and characteristics of Daning River of Three Gorges Reservoir (TGR) were studied. The results suggested that during the period of winter algal blooms centered on Tangjia bay in Daning river, chlorophyll a (Chl-a) had a wide range (the rates of (Chl-a)max and (Chl-a)min is 260). The contents of total nitrogen (TN), total phosphorus (TP) and potassium permanganate index were at very high levels because of bioaccumulation from algal blooms, but the values of dissolved oxygen (DO) and pH were very low. During winter algal blooms fastigium poor algae were observed accounting for 2 phylum 4 species, dominant species are Microcystis aeruginosa and Microcystis flos-aquae, the maximum value of algal density was 3.15 x 10(7) cells/L, and the correlation weighted nutrition state index was 80, which indicated water body was at high eutrophication level. However the spring algal blooms belonged to whole watershed outbreak, the values of Chl-a, TN, TP and potassium permanganate index became all markedly high with outbreak of algal blooms. There were 5 phylum 44 species algae being observed during spring algal blooms fastigium, different sections observed different dominant species and algal density values. The correlation weighted nutrition state index showed water of Dongping bar and Baishui River sections was at slight eutrophication level. During winter algal blooms there were significantly positive correlations between Chl-a and TN, TP, potassium permanganate index, water temperature, between pH and SD. Significantly negative correlations were observed between Chl-a and DO, SD, between pH and TN, TP, potassium permanganate index. In spring algal blooms significantly positive correlations were observed between Chi-a and TP, potassium permanganate index, DO, pH, between pH and Chla, TP, potassium permanganate index, DO, air temperature. Significantly negative correlations were observed between Chl-a and SD, between pH and SD. PMID:20187374

Cao, Cheng-jin; Zheng, Bing-hui; Zhang, Jia-lei; Huang, Min-sheng; Chen, Zhen-lou

2009-12-01

107

HPLC pigment profiles of 31 harmful algal bloom species isolated from the coastal sea areas of China  

NASA Astrophysics Data System (ADS)

Chemotaxonomy based on diagnostic pigments is now a routine tool for macroscopic determination of the composition and abundance of phytoplankton in various aquatic environments. Since the taxonomic capability of this method depends on the relationships between diagnostic pigments and chlorophyll a of classified groups, it is critical to calibrate it by using pigment relationships obtained from representative and/or dominant species local to targeted investigation area. In this study, pigment profiles of 31 harmful algal bloom (HAB) species isolated from the coastal sea areas of China were analyzed with high performance liquid chromatography (HPLC). Pigment compositions, cellular pigment densities and ratios of pigments to chlorophyll a were determined and calculated. Among all these species, 25 kinds of pigments were detected, of which fucoxanthin, peridinin, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, violaxanthin, and antheraxanthin were diagnostic pigments. Cellular pigment density was basically independent of species and environmental conditions, and therefore was recommended as a bridge to compare the results of HPLC-CHEMTAX technique with the traditional microscopy method. Pigment ratios of algal species isolated from the coast of China, especially the diagnostic pigment ratios, were higher than those from other locations. According to these results, pigment ratio ranges of four classes of phytoplankton common off the coast of China were summarized for using in the current chemotaxonomic method. Moreover, the differences of pigments ratios among different species under the same culturing conditions were consistent with their biological differences. Such differences have the potential to be used to classify the phytoplankton below class, which is meaningful for monitoring HABs by HPLC-CHEMTAX.

Liu, Shuxia; Yao, Peng; Yu, Zhigang; Li, Dong; Deng, Chunmei; Zhen, Yu

2014-12-01

108

ALGAL METABOLITE INFLUENCE ON BLOOM SEQUENCE IN EUTROPHIED FRESHWATER PONDS  

EPA Science Inventory

The extracellular metabolites of planktonic bloom dominant algae play a most significant role in the determination of bloom sequence in a eutrophied freshwater pond. Certain extracellular metabolites of planktonic blue-green algae substantially inhibit the growth of planktonic di...

109

Monitoring of ocean surface algal blooms in coastal and oceanic waters around India.  

PubMed

The National Aeronautics and Space Administration's (NASA) sensor MODIS-Aqua provides an important tool for reliable observations of the changing ocean surface algal bloom paradigms in coastal and oceanic waters around India. A time series of the MODIS-Aqua-derived OSABI (ocean surface algal bloom index) and its seasonal composite images report new information and comprehensive pictures of these blooms and their evolution stages in a wide variety of events occurred at different times of the years from 2003 to 2011, providing the first large area survey of such phenomena around India. For most of the years, the results show a strong seasonal pattern of surface algal blooms elucidated by certain physical and meteorological conditions. The extent of these blooms reaches a maximum in winter (November-February) and a minimum in summer (June-September), especially in the northern Arabian Sea. Their spatial distribution and retention period are also significantly increased in the recent years. The increased spatial distribution and intensity of these blooms in the northern Arabian Sea in winter are likely caused by enhanced cooling, increased convective mixing, favorable winds, and atmospheric deposition of the mineral aerosols (from surrounding deserts) of the post-southwest monsoon period. The southward Oman coastal current and southwestward winds become apparently responsible for their extension up to the central Arabian Sea. Strong upwelling along this coast further triggers their initiation and growth. Though there is a warming condition associated with increased sea surface height anomalies along the coasts of India and Sri Lanka in winter, surface algal bloom patches are still persistent along these coasts due to northeast monsoonal winds, enhanced precipitation, and subsequent nutrient enrichment in these areas. The occurrence of the surface algal blooms in the northern Bay of Bengal coincides with a region of the well-known Ganges-Brahmaputra Estuarine Frontal (GBEF) system, which increases supply of nutrients in addition to the land-derived inputs triggering surface algal blooms in this region. Low density (initiation stage) of such blooms observed in clear oceanic waters southeast and northeast of Sri Lanka may be caused by the vertical mixing processes (strong monsoonal winds) and the occurrence of Indian Ocean Dipole events. Findings based on the analyses of time series satellite data indicate that the new information on surface algal blooms will have important bearing on regional fisheries, ecosystem and environmental studies, and implications of climate change scenarios. PMID:24554022

Tholkapiyan, Muniyandi; Shanmugam, Palanisamy; Suresh, T

2014-07-01

110

On the horizontal distribution of algal-bloom in Chaohu Lake and its formation process  

NASA Astrophysics Data System (ADS)

Based on the remote sensing images of algae, the present work analyzes the horizontal distribution characteristics of algal blooms in Chaohu Lake, China, which also reveals the frequency of algal blooms under different wind directions. Further, an unstructured-grid, three-dimensional finite-volume coastal ocean model (FVCOM) is applied to investigate the wind-induced currents and the transport process to explain the reason why algal blooms occur at the detected places. We first deduce the primary distribution of biomass from overlaid satellite images, and explain the formation mechanism by analyzing the pollution sources, and simulating the flow field and transportation process under prevailing wind over Chaohu Lake. And then, we consider the adjustment action of the wind on the corresponding day and develop a two-time scale approach to describe the whole formation process of algae horizontal distribution in Chaohu Lake. That is, on the longer time scale, i.e., during bloom season, prevailing wind determines the primary distribution of biomass by inducing the characteristic flow field; on the shorter time scale, i.e., on the day when bloom occurs, the wind force adjusts the primary distribution of biomass to form the final distribution of algal bloom.

Chen, Yuan-Ying; Liu, Qing-Quan

2014-10-01

111

A Harmful Algal Bloom of Karenia brevis in the Northeastern Gulf of Mexico as Revealed by MODIS and VIIRS: A Comparison.  

PubMed

The most recent Visible Infrared Imager Radiometer Suite (VIIRS) is not equipped with a spectral band to detect solar-stimulated phytoplankton fluorescence. The lack of such a band may affect the ability of VIIRS to detect and quantify harmful algal blooms (HABs) in coastal waters rich in colored dissolved organic matter (CDOM) because of the overlap of CDOM and chlorophyll absorption within the blue-green spectrum. A recent HAB dominated by the toxin-producing dinoflagellate Karenia brevis in the northeastern Gulf of Mexico, offshore of Florida's Big Bend region, allowed for comparison of the capacities of VIIRS and Moderate Resolution Imaging Spectroradiometer (MODIS) to detect blooms in CDOM-rich waters. Both VIIRS and MODIS showed general consistency in mapping the CDOM-rich dark water, which measured a maximum area of 8900 km2 by mid-July 2014. However, within the dark water, only MODIS allowed detection of bloom patches-as indicated by high normalized fluorescence line height (nFLH). Field surveys between late July and mid-September confirmed Karenia brevis at bloom abundances up to 20 million cells·L-1 within these patches. The bloom patches were well captured by the MODIS nFLH images, but not by the default chlorophyll a concentration (Chla) images from either MODIS or VIIRS. Spectral analysis showed that VIIRS could not discriminate these high-phytoplankton water patches within the dark water due to its lack of fluorescence band. Such a deficiency may be overcome with new algorithms or future satellite missions such as the U.S. NASA's Pre-Aerosol-Clouds-Ecology mission and the European Space Agency's Sentinel-3 mission. PMID:25635412

Hu, Chuanmin; Barnes, Brian B; Qi, Lin; Corcoran, Alina A

2015-01-01

112

Approaches for the detection of harmful algal blooms using oligonucleotide interactions.  

PubMed

Blooms of microscopic algae in our waterways are becoming an increasingly important environmental concern. Many are sources of harmful biotoxins that can lead to death in humans, marine life and birds. Additionally, their biomass can cause damage to ecosystems such as oxygen depletion, displacement of species and habitat alteration. Globally, the number and frequency of harmful algal blooms has increased over the last few decades, and monitoring and detection strategies have become essential for managing these events. This review discusses developments in the use of oligonucleotide-based 'molecular probes' for the selective monitoring of algal cell numbers. Specifically, hybridisation techniques will be a focus. PMID:25381608

Bruce, Karen L; Leterme, Sophie C; Ellis, Amanda V; Lenehan, Claire E

2015-01-01

113

Preparation of a new-style composite containing a key bioflocculant produced by Pseudomonas aeruginosa ZJU1 and its flocculating effect on harmful algal blooms.  

PubMed

A novel composite consisting of clay, bioflocculant, and inorganic flocculant was designed, and its flocculating effect on harmful algal blooms (HABs) was studied in this study. The extracellular polymeric substances (EPS), produced with a yield of 3.58±0.11g/L by a newly isolated Pseudomonas aeruginosa ZJU1, was indicated to be a key component in the composite. The components and functional groups of the EPS were analyzed, and it showed that polysaccharides, proteins, and nucleic acids are the main components; polar functional groups in the EPS are responsible for its flocculating activity. The novel composite was optimized by the response surface methodology and after optimization, the optical components and contents of the composite were Kaolin 2.38g/L, CaCl2 0.28g/L, KAl(SO4)2 0.09g/L, and EPS 1.75mg/L. The flocculating rates of the composite were tested, and it could rapidly reach 100±0.13% within 2min when OD680 of Microcystis aeruginosa was 0.1; it could reach 100±0.08% within 5min for OD680 of M. aeruginosa in HABs up to 1.0. These results suggest that the novel composite will be a highly efficient material for the treatment of HABs caused by M. aeruginosa. PMID:25463236

Sun, Peng-Fei; Lin, Hui; Wang, Guan; Lu, Li-Ling; Zhao, Yu-Hua

2015-03-01

114

Longitudinal Hydrodynamic Characteristics in Reservoir Tributary Embayments and Effects on Algal Blooms  

PubMed Central

Three Gorges Reservoir (TGR) is one of the largest man-made lakes in the world. Since the impoundment in 2003, however, algal blooms have been often observed in the tributary embayments. To control the algal blooms, a thorough understanding of the hydrodynamics (e.g., flow regime, velocity gradient, and velocity magnitude and direction) in the tributary embayments is particularly important. Using a calibrated three-dimensional hydrodynamic model, we carried out a hydrodynamic analysis of a typical tributary embayment (i.e., Xiangxi Bay) with emphasis on the longitudinal patterns. The results show distinct longitudinal gradients of hydrodynamics in the study area, which can be generally characterized as four zones: riverine, intermediate, lacustrine, and mainstream influenced zones. Compared with the typical longitudinal zonation for a pure reservoir, there is an additional mainstream influenced zone near the mouth due to the strong effects of TGR mainstream. The blooms are prone to occur in the intermediate and lacustrine zones; however, the hydrodynamic conditions of riverine and mainstream influence zones are not propitious for the formation of algal blooms. This finding helps to diagnose the sensitive areas for algal bloom occurrence. PMID:23874534

Dai, Huichao; Mao, Jingqiao; Jiang, Dingguo; Wang, Lingling

2013-01-01

115

Analysis of algal bloom risk with uncertainties in lakes by integrating self-organizing map and fuzzy information theory.  

PubMed

Algal blooms are a serious problem in waters, which damage aquatic ecosystems and threaten drinking water safety. However, the outbreak mechanism of algal blooms is very complex with great uncertainty, especially for large water bodies where environmental conditions have obvious variation in both space and time. This study developed an innovative method which integrated a self-organizing map (SOM) and fuzzy information diffusion theory to comprehensively analyze algal bloom risks with uncertainties. The Lake Taihu was taken as study case and the long-term (2004-2010) on-site monitoring data were used. The results showed that algal blooms in Taihu Lake were classified into four categories and exhibited obvious spatial-temporal patterns. The lake was mainly characterized by moderate bloom but had high uncertainty, whereas severe blooms with low uncertainty were observed in the northwest part of the lake. The study gives insight on the spatial-temporal dynamics of algal blooms, and should help government and decision-makers outline policies and practices on bloom monitoring and prevention. The developed method provides a promising approach to estimate algal bloom risks under uncertainties. PMID:24657580

Chen, Qiuwen; Rui, Han; Li, Weifeng; Zhang, Yanhui

2014-06-01

116

[Algal blooms at Banderas Bay, México (2000-2001), from SeaWiFS-sensor-data].  

PubMed

Algal blooms for the period of 2000 and 2001 at Banderas Bay, México, were analyzed from SeaWiFS-ocean-color-sensor derived information. These events were related with the maximum chlorophyll week anomalies (ASi; a proxy variable constructed for the analysis of chlorophyll temporal variation in the bay). The winter-spring blooms were multispecific, while the summer-fall blooms were monospecific. Two proposals are made: (1) Winter-spring blooms are strongly related with mesoescale processes, due to their apparent temporal synchrony with the high chlorophyll levels in the coastal region from Sinaloa to Jalisco states; (2) Cochlodinium polykrikoides (Margalef 1961) blooms during the summer-fall periods could be induced by local conditions and the influence of previous events on the ecosystem. PMID:19419074

Gómez-Villarreal, María C; Martínez-Gaxiola, Marcos D; Peña-Manjarrez, José L

2008-12-01

117

Meteorological influences on algal bloom potential in a nutrient-rich blackwater river  

EPA Science Inventory

The effect of variability in rainfall on the potential for algal blooms was examined for the St. Johns River in northeast Florida. Water chemistry and phytoplankton data were collected at selected sites monthly from 1993 through 2003. Information on rainfall and estimates ofw at...

118

APPLICATION OF HYPERSPECTRAL IMAGERY AND DIGITAL VIDEOGRAPHY TO MANAGE ALGAL BLOOMS IN AQUACULTURE SYSTEMS: CURRENT STATUS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Detection of harmful algal blooms in Case II hypereutrophic aquaculture systems continues to be a challenge. Attempts to isolate certain pond constituents have been difficult because both organic matter and suspended sediments can mask detection of these components. A three band reciprocal reflectan...

119

Freshwater harmful algal bloom exposure – an emerging health risk for recreational water users  

EPA Science Inventory

Freshwater harmful algal bloom exposure – an emerging health risk for recreational water users Elizabeth D. Hilborn1, Virginia A. Roberts2, Lorraine C. Backer3, Jonathan S. Yoder2, Timothy J. Wade1, Michele C. Hlavsa2 1Environmental Public Health Division, Office of Researc...

120

A PILOT PROJECT TO DETECT AND PREDICT HARMFUL ALGAL BLOOMS IN THE NORTHERN GULF OF MEXICO  

EPA Science Inventory

More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this, a workshop was held to develop a user-driven, end-to-end (measurements to applicat...

121

A PILOT PROJECT TO DETECT AND FORECAST HARMFUL ALGAL BLOOMS IN THE NORTHERN GULF OF MEXICO  

EPA Science Inventory

More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this in the northern Gulf of Mexico, a pilot project was initiated to develop a user-dr...

122

Application of Multispectral and Hyperspectral Remote Sensing For Detection of Freshwater Harmful Algal Blooms  

NASA Astrophysics Data System (ADS)

Freshwater Cyanobacterial Harmful algal blooms (CHABs) represent a pressing and apparently increasing threat to both human and environmental health. In California, toxin producing blooms of several species, including Aphanizomenon, Microcystis, Lyngbya, and Anabaena are common; toxins from these blooms have been linked to impaired drinking water, domestic and wild animal deaths, and increasing evidence for toxin transfer to coastal marine environments, including the death of several California sea otters, a threatened marine species. California scientists and managers are under increasing pressure to identify and mitigate these potentially toxic blooms, but point-source measurements and grab samples have been less than effective. There is increasing awareness that these toxic events are both spatially widespread and ephememeral, leading to the need for better monitoring methods applicable to large spatial and temporal scales. Based on monitoring in several California water bodies, it appears that Aphanizomenon blooms frequently precede dangerous levels of toxins from Microcystis. We are exploring new detection methods for identifying CHABs and potentially distinguishing between blooms of the harmful cyanobacteria Aphanizomenon and Microcystis using remote sensing reflectance from a variety of airborne and satellite sensors. We suggest that Aphanizomenon blooms could potentially be used as an early warning of more highly toxic subsequent blooms, and that these methods, combined with better toxin monitoring, can lead to improved understanding and prediction of CHABs by pinpointing problematic watersheds.

Kudela, R. M.; Accorsi, E.; Austerberry, D.; Palacios, S. L.

2013-12-01

123

Health Effects of Toxin-Producing Cyanobacteria: “The CyanoHABs  

Microsoft Academic Search

Increasingly, harmful algal blooms (HABs) are being reported worldwide due to several factors, primarily eutrophication, climate change and more scientific monitoring. All but cyanobacteria toxin poisonings (CTPs) are mainly a marine occurrence. CTPs occur in fresh (lakes, ponds, rivers and reservoirs) and brackish (seas, estuaries, and lakes) waters throughout the world. Organisms responsible include an estimated 40 genera but the

Wayne W. Carmichael

2001-01-01

124

The efficacy and mechanisms of fungal suppression of freshwater harmful algal bloom species.  

PubMed

Microorganisms have attracted worldwide attention as possible agents for inhibiting water blooms. Algae are usually indirectly inhibited and degraded by secretion from microorganisms. In this study, algal cultures Microcystis aeruginosa (Ma) FACH-918, Microcystis flos-aquae (Mf) FACH-1028, Oocystis borgei (Ob) FACH-1108, and M. aeruginosa PCC 7806 were co-cultured with the fungus strain Trichaptum abietinum 1302BG. All algal cells were destroyed within 48 hours (h) of co-incubation. Scanning electron microscope and transmission electron microscope observation revealed that the fungal strain had preying ability on the algal cells. The mechanism may be that the algal cells were encased with a mucous membrane secreted by the fungal mycelia, and finally degraded by the fungus directly. PMID:20675050

Jia, Yong; Han, Guomin; Wang, Congyan; Guo, Peng; Jiang, Wenxin; Li, Xiaona; Tian, Xingjun

2010-11-15

125

Monitoring cyanobacteria-dominant algal blooms in eutrophicated Taihu Lake in China with synthetic aperture radar images  

NASA Astrophysics Data System (ADS)

Monitoring algal blooms by optical remote sensing is limited by cloud cover. In this study, synthetic aperture radar (SAR) was deployed with the aim of monitoring cyanobacteria-dominant algal blooms in Taihu Lake in cloudy weather. The study shows that dark regions in the SAR images caused by cyanobacterial blooms damped the microwave backscatter of the lake surface and were consistent with the regions of algal blooms in quasi-synchronous optical images, confirming the applicability of SAR for detection of surface blooms. Low backscatter may also be associated with other factors such as low wind speeds, resulting in interference when monitoring algal blooms using SAR data alone. After feature extraction and selection, the dark regions were classified by the support vector machine method with an overall accuracy of 67.74%. SAR can provide a reference point for monitoring cyanobacterial blooms in the lake, particularly when weather is not suitable for optical remote sensing. Multi-polarization and multi-band SAR can be considered for use in the future to obtain more accurate information regarding algal blooms from SAR data.

Wang, Ganlin; Li, Junsheng; Zhang, Bing; Shen, Qian; Zhang, Fangfang

2015-01-01

126

Species identification of mixed algal bloom in the Northern Arabian Sea using remote sensing techniques.  

PubMed

Oceanic waters of the Northern Arabian Sea experience massive algal blooms during winter-spring (mid Feb-end Mar), which prevail for at least for 3 months covering the entire northern half of the basin from east to west. Ship cruises were conducted during winter-spring of 2001-2012 covering different stages of the bloom to study the biogeochemistry of the region. Phytoplankton analysis indicated the presence of green tides of dinoflagellate, Noctiluca scintillans (=N. miliaris), in the oceanic waters. Our observations indicated that diatoms are coupled and often co-exist with N. scintillans, making it a mixed-species ecosystem. In this paper, we describe an approach for detection of bloom-forming algae N. scintillans and its discrimination from diatoms using Moderate Resolution Imaging Spectroradiometer (MODIS)-Aqua data in a mixed-species environment. In situ remote sensing reflectance spectra were generated using Satlantic™ hyperspectral radiometer for the bloom and non-bloom waters. Spectral shapes of the reflectance spectra for different water types were distinct, and the same were used for species identification. Scatter of points representing different phytoplankton classes on a derivative plot revealed four diverse clusters, viz. N. scintillans, diatoms, non-bloom oceanic, and non-bloom coastal waters. The criteria developed for species discrimination were implemented on MODIS data and validated using inputs from a recent ship cruise conducted in March 2013. PMID:25638059

Dwivedi, R; Rafeeq, M; Smitha, B R; Padmakumar, K B; Thomas, Lathika Cicily; Sanjeevan, V N; Prakash, Prince; Raman, Mini

2015-02-01

127

A multispectral analysis of algal bloom in the Gulf of Mexico  

NASA Technical Reports Server (NTRS)

Skylab multispectral scanner data acquired on January 21, 1974, were used to study the spectral characteristics of an algal bloom in the Gulf of Mexico west of Fort Myers, Florida. Radiance profiles of the water and algae were prepared with data from ten bands of the S192 scanner covering the spectral range from .42 to 2.35 micrometers. The high spectral response in the near-infrared spectral bands implies a possible classification and discrimination parameter for detection of blooms of phytoplankton concentrations such as the so-called red tides of Florida.

Johnson, W. R.; Norris, D. R.

1977-01-01

128

Comparison of multi-sensor data application in algal bloom detection  

Microsoft Academic Search

Satellite remote sensing plays a significant role in algal bloom monitoring and detection over these decades. Different satellite data from SeaWiFS, MODIS\\/Aqua, MODIS\\/Terra and MERIS were processed for East China Sea in May 2008. Derived normalized water-leaving radiance (nLw), chlorophyll concentration (Chl) and fluorescence line height (FLH) were compared and analysed for these sensors. The comparison results show that nLw

Liya Sun; Yunzhi Chen; Xiaoqin Wang

2010-01-01

129

Bacterial Community Structure Associated with a Dimethylsulfoniopropionate-Producing North Atlantic Algal Bloom  

PubMed Central

The bacteria associated with oceanic algal blooms are acknowledged to play important roles in carbon, nitrogen, and sulfur cycling, yet little information is available on their identities or phylogenetic affiliations. Three culture-independent methods were used to characterize bacteria from a dimethylsulfoniopropionate (DMSP)-producing algal bloom in the North Atlantic. Group-specific 16S rRNA-targeted oligonucleotides, 16S ribosomal DNA (rDNA) clone libraries, and terminal restriction fragment length polymorphism analysis all indicated that the marine Roseobacter lineage was numerically important in the heterotrophic bacterial community, averaging >20% of the 16S rDNA sampled. Two other groups of heterotrophic bacteria, the SAR86 and SAR11 clades, were also shown by the three 16S rRNA-based methods to be abundant in the bloom community. In surface waters, the Roseobacter, SAR86, and SAR11 lineages together accounted for over 50% of the bacterial rDNA and showed little spatial variability in abundance despite variations in the dominant algal species. Depth profiles indicated that Roseobacter phylotype abundance decreased with depth and was positively correlated with chlorophyll a, DMSP, and total organic sulfur (dimethyl sulfide plus DMSP plus dimethyl sulfoxide) concentrations. Based on these data and previous physiological studies of cultured Roseobacter strains, we hypothesize that this lineage plays a role in cycling organic sulfur compounds produced within the bloom. Three other abundant bacterial phylotypes (representing a cyanobacterium and two members of the ? Proteobacteria) were primarily associated with chlorophyll-rich surface waters of the bloom (0 to 50 m), while two others (representing Cytophagales and ? Proteobacteria) were primarily found in deeper waters (200 to 500 m). PMID:11010865

González, José M.; Simó, Rafel; Massana, Ramon; Covert, Joseph S.; Casamayor, Emilio O.; Pedrós-Alió, Carlos; Moran, Mary Ann

2000-01-01

130

Recreational exposure to low concentrations of microcystins during an algal bloom in a small lake.  

PubMed

We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-microg/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses), but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 microg/L to 5 microg/L) in the water and (<0.1 ng/m(3)) in the aerosol samples. Blood levels of microcystins for all participants were below the limit of detection (0.147 microg/L). Given this low exposure level, study participants reported no symptom increases following recreational exposure to microcystins. This is the first study to report that water-based recreational activities can expose people to very low concentrations of aerosol-borne microcystins; we recently conducted another field study to assess exposures to higher concentrations of these algal toxins. PMID:18728733

Backer, Lorraine C; Carmichael, Wayne; Kirkpatrick, Barbara; Williams, Christopher; Irvin, Mitch; Zhou, Yue; Johnson, Trisha B; Nierenberg, Kate; Hill, Vincent R; Kieszak, Stephanie M; Cheng, Yung-Sung

2008-01-01

131

Recreational Exposure to Low Concentrations of Microcystins During an Algal Bloom in a Small Lake  

PubMed Central

We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-?g/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses), but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 ?g/L to 5 ?g/L) in the water and (<0.1 ng/m3) in the aerosol samples. Blood levels of microcystins for all participants were below the limit of detection (0.147?g/L). Given this low exposure level, study participants reported no symptom increases following recreational exposure to microcystins. This is the first study to report that water-based recreational activities can expose people to very low concentrations of aerosol-borne microcystins; we recently conducted another field study to assess exposures to higher concentrations of these algal toxins. PMID:18728733

Backer, Lorraine C.; Carmichael, Wayne; Kirkpatrick, Barbara; Williams, Christopher; Irvin, Mitch; Zhou, Yue; Johnson, Trisha B.; Nierenberg, Kate; Hill, Vincent R.; Kieszak, Stephanie M.; Cheng, Yung-Sung

2008-01-01

132

Effects of suspended and sedimented clays on juvenile hard clams, Mercenaria mercenaria , within the context of harmful algal bloom mitigation  

Microsoft Academic Search

Increased interest in using ecologically inert clays to flocculate, sediment, and thus mitigate harmful algal blooms at nearshore mariculture sites has prompted studies on the effectiveness of this method on prolific blooms, such as those caused by the neurotoxic dinoflagellate Karenia brevis in the Gulf of Mexico. Potential repercussions of this control strategy revolve around the increased flux of suspended

Marie-Claude Archambault; V. Monica Bricelj; Jon Grant; Donald M. Anderson

2004-01-01

133

Use of two-dimensional gel electrophoresis to differentiate morphospecies of Alexandrium minutum, a paralytic shellfish poisoning toxin-producing dinoflagellate of harmful algal blooms.  

PubMed

Contamination of shellfish with paralytic shellfish poisoning toxins (PST) produced by toxic harmful algal blooms (HABs) have been negatively affecting the shellfish and aquaculture industries worldwide. Therefore, accurate and early identification of toxic phytoplankton species is crucial in HABs surveillance programs that allow fish-farmers to take appropriate preventive measures in shellfish harvesting and other aquaculture activities to overcome the negative impacts of HABs on human health. The identification of toxic dinoflagellates present in the water is currently a time-consuming operation since it requires skillful taxonomists and toxicologists equipped with optical and scanning electron microscopes as well as sophisticated equipment, for example, high-performance liquid chromotography-fluorescence detection. In this paper, a two-dimensional gel electrophoresis (2-DE)-based proteomic approach was applied to discriminate between toxic and nontoxic strains of Alexandrium minutum. Variation in morphological features between toxic and nontoxic strains was minimal and not significant. Also, variation in 2-DE protein patterns within either toxic or nontoxic strains was low, but pronounced differences were detected between toxic and nontoxic strains. The most notable differences between these strains were several abundant proteins with pIs ranging from 4.8 to 5.3 and apparent molecular masses between 17.5 and 21.5 kDa. Groups of proteins, namely NT1, NT2, NT3, and NT4, were consistently found in all nontoxic strains, while T1 and T2 were prominent in the toxic strains. These specific protein spots characteristic for toxic and nontoxic strains remained clearly distinguishable irrespective of the various growth conditions tested. Therefore, they have the potential to serve as "taxonomic markers" to distinguish toxic and nontoxic strains within A. minutum. Initial studies revealed that the expression pattern of T1 was tightly correlated to toxin biosynthesis in the examined alga and may be used to serve as a potential toxin indicator. PMID:15800974

Chan, Leo Lai; Hodgkiss, Ivor John; Lam, Paul Kwan-Sing; Wan, Jennifer Man-Fan; Chou, Hong-Nong; Lum, John Hon-Kei; Lo, Maria Gar-Yee; Mak, Abby Sin-Chi; Sit, Wai-Hung; Lo, Samuel Chun-Lap

2005-04-01

134

Decoupling physical from biological processes to assess the impact of viruses on a mesoscale algal bloom.  

PubMed

Phytoplankton blooms are ephemeral events of exceptionally high primary productivity that regulate the flux of carbon across marine food webs [1-3]. Quantification of bloom turnover [4] is limited by a fundamental difficulty to decouple between physical and biological processes as observed by ocean color satellite data. This limitation hinders the quantification of bloom demise and its regulation by biological processes [5, 6], which has important consequences on the efficiency of the biological pump of carbon to the deep ocean [7-9]. Here, we address this challenge and quantify algal blooms' turnover using a combination of satellite and in situ data, which allows identification of a relatively stable oceanic patch that is subject to little mixing with its surroundings. Using a newly developed multisatellite Lagrangian diagnostic, we decouple the contributions of physical and biological processes, allowing quantification of a complete life cycle of a mesoscale (?10-100 km) bloom of coccolithophores in the North Atlantic, from exponential growth to its rapid demise. We estimate the amount of organic carbon produced during the bloom to be in the order of 24,000 tons, of which two-thirds were turned over within 1 week. Complimentary in situ measurements of the same patch area revealed high levels of specific viruses infecting coccolithophore cells, therefore pointing at the importance of viral infection as a possible mortality agent. Application of the newly developed satellite-based approaches opens the way for large-scale quantification of the impact of diverse environmental stresses on the fate of phytoplankton blooms and derived carbon in the ocean. PMID:25155511

Lehahn, Yoav; Koren, Ilan; Schatz, Daniella; Frada, Miguel; Sheyn, Uri; Boss, Emmanuel; Efrati, Shai; Rudich, Yinon; Trainic, Miri; Sharoni, Shlomit; Laber, Christian; DiTullio, Giacomo R; Coolen, Marco J L; Martins, Ana Maria; Van Mooy, Benjamin A S; Bidle, Kay D; Vardi, Assaf

2014-09-01

135

Quantifying Phycocyanin Concentration in Cyanobacterial Algal Blooms from Remote Sensing Reflectance-A Quasi Analytical Approach  

NASA Astrophysics Data System (ADS)

Cyanobacterial harmful algal blooms (CHAB) are notorious for depleting dissolved oxygen level, producing various toxins, causing threats to aquatic life, altering the food-web dynamics and the overall ecosystem functioning in inland lakes, estuaries, and coastal waters. Most of these algal blooms produce various toxins that can damage cells, tissues and even cause mortality of living organisms. Frequent monitoring of water quality in a synoptic scale has been possible by the virtue of remote sensing techniques. In this research, we present a novel technique to monitor CHAB using remote sensing reflectance products. We have modified a multi-band quasi analytical algorithm that determines phytoplankton absorption coefficients from above surface remote sensing reflectance measurements using an inversion method. In situ hyperspectral remote sensing reflectance data were collected from several highly turbid and productive aquaculture ponds. A novel technique was developed to further decompose the phytoplankton absorption coefficients at 620 nm and obtain phycocyanin absorption coefficient at the same wavelength. An empirical relationship was established between phycocyanin absorption coefficients at 620 nm and measured phycocyanin concentrations. Model calibration showed strong relationship between phycocyanin absorption coefficients and phycocyanin pigment concentration (r2=0.94). Validation of the model in a separate dataset produced a root mean squared error of 167 mg m-3 (phycocyanin range: 26-1012 mg m-3). Results demonstrate that the new approach will be suitable for quantifying phycocyanin concentration in cyanobacteria dominated turbid productive waters. Band architecture of the model matches with the band configuration of the Medium Resolution Imaging Spectrometer (MERIS) and assures that MERIS reflectance products can be used to quantify phycocyanin in cyanobacterial harmful algal blooms in optically complex waters.

Mishra, S.; Mishra, D. R.; Tucker, C.

2011-12-01

136

Limnology of Oneida Lake with emphasis on factors contributing to algal blooms  

USGS Publications Warehouse

Oneida Lake is a naturally eutrophic lake that has existed for about 10,500 years. It has been in a eutrophic state for at least 350 years, and the geochemically derived dissolved materials entering the lake from the drainage basin are of sufficient quantity (449,700 tones per year) to support annual algal blooms. The greatest amount of the dissolved materials (72 percent) comes from the southern tributaries to the lake, of which Chittenango Creek carries the largest load of almost all major chemical substances. The stream contributes 37 percent of all dissolved solids entering the lake. Ground water is negligible in both the water and the nutrient budgets.

Greeson, Phillip E.

1971-01-01

137

Remote sensing models using Landsat satellite data to monitor algal blooms in Lake Champlain.  

PubMed

Lake Champlain is significantly impaired by excess phosphorus loading, requiring frequent lake-wide monitoring for eutrophic conditions and algal blooms. Satellite remote sensing provides regular, synoptic coverage of algal production over large areas with better spatial and temporal resolution compared with in situ monitoring. This study developed two algal production models using Landsat Enhanced Thematic Mapper Plus (ETM(+)) satellite imagery: a single band model and a band ratio model. The models predicted chlorophyll a concentrations to estimate algal cell densities throughout Lake Champlain. Each model was calibrated with in situ data compiled from summer 2006 (July 24 to September 10), and then validated with data for individual days in August 2007 and 2008. Validation results for the final single band and band ratio models produced Nash-Sutcliffe efficiency (NSE) coefficients of 0.65 and 0.66, respectively, confirming satisfactory model performance for both models. Because these models have been validated over multiple days and years, they can be applied for continuous monitoring of the lake. PMID:23416605

Trescott, A; Park, M-H

2013-01-01

138

Applications of MODIS Fluorescent Line Height Measurements to Monitor Water Quality Trends and Algal Bloom Activity  

NASA Technical Reports Server (NTRS)

Recent advances in satellite and airborne remote sensing, such as improvements in sensor and algorithm calibrations, processing techniques and atmospheric correction procedures have provided for increased coverage of remote-sensing, ocean-color products for coastal regions. In particular, for the Moderate Resolution Imaging Spectrometer (MODIS) sensor calibration updates, improved aerosol retrievals and new aerosol models has led to improved atmospheric correction algorithms for turbid waters and have improved the retrieval of ocean color in coastal waters. This has opened the way for studying ocean phenomena and processes at finer spatial scales, such as the interactions at the land-sea interface, trends in coastal water quality and algal blooms. Human population growth and changes in coastal management practices have brought about significant changes in the concentrations of organic and inorganic, particulate and dissolved substances entering the coastal ocean. There is increasing concern that these inputs have led to declines in water quality and have increase local concentrations of phytoplankton, which cause harmful algal blooms. In two case studies we present MODIS observations of fluorescence line height (FLH) to 1) assess trends in water quality for Tampa Bay, Florida and 2) illustrate seasonal and annual variability of algal bloom activity in Monterey Bay, California as well as document estuarine/riverine plume induced red tide events. In a comprehensive analysis of long term (2003-2011) in situ monitoring data and satellite imagery from Tampa Bay we assess the validity of the MODIS FLH product against chlorophyll-a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions and to develop a near decadal trend in water quality changes. In situ monitoring locations that correlated well with satellite imagery were in depths greater than seven meters and were located over five kilometers from shore. Water quality parameter of total nitrogen, phosphorous, turbidity and biological oxygen demand had high correlations with these sites, as well. Satellite FLH estimates show improving water quality from 2003-2007 with a slight decline up through 2011. Dinoflagellate blooms in Monterey Bay, California (USA) have recently increased in frequency and intensity. Nine years of MODIS FLH observations are used to describe the annual and seasonal variability of bloom activity within the Bay. Three classes of MODIS algorithms were correlated against in situ chlorophyll measurements. The FLH algorithm provided the most robust estimate of bloom activity. Elevated concentrations of phytoplankton were evident during the months of August-November, a period during which increased occurrences of dinoflagellate blooms have been observed in situ. Seasonal patterns of FLH show the on- and offshore movement of areas of high phytoplankton biomass between oceanographic seasons. Higher concentrations of phytoplankton are also evident in the vicinity of the land-based nutrient sources and outflows, and the cyclonic bay-wide circulation can transport these nutrients to the northern Bay bloom incubation region. Both of these case studies illustrate the utility MODIS FLH observations in supporting management decisions in coastal and estuarine waters.

Fischer, Andrew; Moreno-Mardinan, Max; Ryan, John P.

2012-01-01

139

Harmful algal blooms in the Chesapeake and Coastal Bays of Maryland, USA: Comparison of 1997, 1998, and 1999 events  

Microsoft Academic Search

Harmful algal blooms in the Chesapeake Bay and coastal bays of Maryland, USA, are not a new phenomenon, but may be increasing\\u000a in frequency and diversity. Outbreaks ofPfiesteria piscicida (Dinophyceae) were observed during 1997 in several Chesapeake Bay tributaries, while in 1998,Pfiesteria-related events were not found but massive blooms ofProrocentrum minimum (Dinophyceae) occurred. In 1999,Aureococcus anophagefferens (Pelagophyceae) developed in the

Patricia M. Glibert; Robert Magnien; Michael W. Lomas; Jeffrey Alexander; Chunlei Tan; Erin Haramoto; Mark Trice; Todd M. Kana

2001-01-01

140

Remote sensing of cyanobacteria-dominant algal blooms and water quality parameters in Zeekoevlei, a small hypertrophic lake, using MERIS  

Microsoft Academic Search

Eutrophication and cyanobacterial algal blooms present an increasing threat to the health of freshwater ecosystems and to humans who use these resources for drinking and recreation. Remote sensing is being used increasingly as a tool for monitoring these phenomena in inland and near-coastal waters. This study uses the Medium Resolution Imaging Spectrometer (MERIS) to view Zeekoevlei, a small hypertrophic freshwater

Mark W. Matthews; Stewart Bernard; Kevin Winter

2010-01-01

141

Cochlodinium polykrikoides blooms and clonal isolates from the northwest Atlantic coast cause rapid mortality in larvae of multiple bivalve species  

Microsoft Academic Search

Globally, many commercial bivalve populations have declined in recent decades. In addition to overharvesting and habitat loss,\\u000a the increasing frequency and intensity of harmful algal blooms (HABs) are likely to contribute to bivalve losses, particularly\\u000a in cases where blooms negatively impact larval stages. This paper reports on the lethal effects of clonal cultures and blooms\\u000a of Cochlodinium polykrikoides from the

Ying Zhong Tang; Christopher J. Gobler

2009-01-01

142

Predicting Harmful Algal Blooms: A Case Study with Dinophysis ovum in the Gulf of Mexico  

E-print Network

analyzed to identify the conditions necessary for bloom initiation or presence with the goal of predicting future blooms of Dinophysis. I determined that a narrow range of temperature and salinity may be necessary for bloom initiation of Dinophysis...

Harred, Laura B

2014-04-10

143

Evidence for a novel marine harmful algal bloom: cyanotoxin (microcystin) transfer from land to sea otters.  

PubMed

"Super-blooms" of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine "harmful algal bloom" in the Pacific coastal environment; that of hepatotoxic shellfish poisoning (HSP), suggesting that animals and humans are at risk from microcystin poisoning when consuming shellfish harvested at the land-sea interface. PMID:20844747

Miller, Melissa A; Kudela, Raphael M; Mekebri, Abdu; Crane, Dave; Oates, Stori C; Tinker, M Timothy; Staedler, Michelle; Miller, Woutrina A; Toy-Choutka, Sharon; Dominik, Clare; Hardin, Dane; Langlois, Gregg; Murray, Michael; Ward, Kim; Jessup, David A

2010-01-01

144

Verification and Validation of NASA-Supported Enhancements to the Near Real Time Harmful Algal Blooms Observing System (HABSOS)  

NASA Technical Reports Server (NTRS)

This report discusses verification and validation (V&V) assessment of Moderate Resolution Imaging Spectroradiometer (MODIS) ocean data products contributed by the Naval Research Laboratory (NRL) and Applied Coherent Technologies (ACT) Corporation to National Oceanic Atmospheric Administration s (NOAA) Near Real Time (NRT) Harmful Algal Blooms Observing System (HABSOS). HABSOS is a maturing decision support tool (DST) used by NOAA and its partners involved with coastal and public health management.

Hall, Calllie; McPherson, Terry; Spiering, Bruce; Brown, Richard; Estep, Lee; Lunde, Bruce; Guest, DeNeice; Navard, Andy; Pagnutti, Mary; Ryan, Robert E.; Spruce, Joseph P.

2006-01-01

145

Short-term temporal variations in iron concentration and speciation in a canal during a summer algal bloom  

Microsoft Academic Search

.  We conducted field investigations in a canal connected to Lake Kasumigaura (Japan) twice weekly during a summer algal bloom\\u000a to understand the temporal variations in dissolved iron and its speciation, and the controlling factors. Dissolved iron (D-Fe),\\u000a which is operationally defined as that passing through a 0.2-?m pore filter, acid-labile particulate iron (LP-Fe), and chemical\\u000a speciation of dissolved iron were

Takashi Nagai; Akio Imai; Kazuo Matsushige; Kunihiko Yokoi; Takehiko Fukushima

2008-01-01

146

A novel remote sensing algorithm to quantify phycocyanin in cyanobacterial algal blooms  

NASA Astrophysics Data System (ADS)

We present a novel three-band algorithm (PC3) to retrieve phycocyanin (PC) pigment concentration in cyanobacteria laden inland waters. The water sample and remote sensing reflectance data used for PC3 calibration and validation were acquired from highly turbid productive catfish aquaculture ponds. Since the characteristic PC absorption feature at 620 nm is contaminated with residual chlorophyll-a (Chl-a) absorption, we propose a coefficient (?) for isolating the PC absorption component at 620 nm. Results show that inclusion of the model coefficient relating Chl-a absorption at 620 nm–665 nm enables PC3 to compensate for the confounding effect of Chl-a at the PC absorption band and considerably increases the accuracy of the PC prediction algorithm. In the current dataset, PC3 produced the lowest mean relative error of prediction among all PC algorithms considered in this research. Moreover, PC3 eliminates the nonlinear sensitivity issue of PC algorithms particularly at high PC range (>100 ?g L?1). Therefore, introduction of PC3 will have an immediate positive impact on studies monitoring inland and coastal cyanobacterial harmful algal blooms.

Mishra, S.; Mishra, D. R.

2014-11-01

147

Human illnesses and animal deaths associated with freshwater harmful algal blooms-kansas.  

PubMed

Freshwater harmful algal bloom (FHAB) toxins can cause morbidity and mortality in both humans and animals, and the incidence of FHABs in the United States and Kansas has increased. In 2010, the Kansas Department of Health and Environment (KDHE) developed a FHAB policy and response plan. We describe the epidemiology of FHAB-associated morbidity and mortality in humans and animals in Kansas. Healthcare providers and veterinarians voluntarily reported FHAB-associated cases to KDHE. An investigation was initiated for each report to determine the source of exposure and to initiate public health mitigation actions. There were 38 water bodies with a confirmed FHAB in 2011. There were 34 reports of human and animal FHAB-associated health events in 2011, which included five dog deaths and hospitalization of two human case patients. Five confirmed human illnesses, two dog illnesses and five dog deaths were associated with one lake. Four human and seven dog cases were exposed to the lake after a public health alert was issued. Public health officials and FHAB partners must ensure continued awareness of the risks to the public, educate healthcare providers and veterinarians on FHAB-related health events and encourage timely reporting to public health authorities. PMID:25647780

Trevino-Garrison, Ingrid; DeMent, Jamie; Ahmed, Farah S; Haines-Lieber, Patricia; Langer, Thomas; Ménager, Henri; Neff, Janet; van der Merwe, Deon; Carney, Edward

2015-01-01

148

sxtA-Based Quantitative Molecular Assay To Identify Saxitoxin-Producing Harmful Algal Blooms in Marine Waters ? †  

PubMed Central

The recent identification of genes involved in the production of the potent neurotoxin and keystone metabolite saxitoxin (STX) in marine eukaryotic phytoplankton has allowed us for the first time to develop molecular genetic methods to investigate the chemical ecology of harmful algal blooms in situ. We present a novel method for detecting and quantifying the potential for STX production in marine environmental samples. Our assay detects a domain of the gene sxtA that encodes a unique enzyme putatively involved in the sxt pathway in marine dinoflagellates, sxtA4. A product of the correct size was recovered from nine strains of four species of STX-producing Alexandrium and Gymnodinium catenatum and was not detected in the non-STX-producing Alexandrium species, other dinoflagellate cultures, or an environmental sample that did not contain known STX-producing species. However, sxtA4 was also detected in the non-STX-producing strain of Alexandrium tamarense, Tasmanian ribotype. We investigated the copy number of sxtA4 in three strains of Alexandrium catenella and found it to be relatively constant among strains. Using our novel method, we detected and quantified sxtA4 in three environmental blooms of Alexandrium catenella that led to STX uptake in oysters. We conclude that this method shows promise as an accurate, fast, and cost-effective means of quantifying the potential for STX production in marine samples and will be useful for biological oceanographic research and harmful algal bloom monitoring. PMID:21841034

Murray, Shauna A.; Wiese, Maria; Stüken, Anke; Brett, Steve; Kellmann, Ralf; Hallegraeff, Gustaaf; Neilan, Brett A.

2011-01-01

149

Planning applications in east central Florida. [resources management and planning, land use, and lake algal blooms in Brevard County from Skylab imagery  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Lake Apopka and three lakes downstream of it (Dora, Eustis, and Griffin) are in an advanced state of eutrophication with high algal concentrations. This feature has shown up consistently on ERTS-1 images in the form of a characteristic water color for those lakes. As expected, EREP photographs also show a characteristic color for those lakes. What was not expected is that Lake Griffin shows a clear pattern of this coloration. Personnel familiar with the lake believe that the photograph does, indeed, show an algal bloom. It is reported that the algal concentration is often significantly higher in the southern portion of the lake. What the photograph shows that was not otherwise known is the pattern of the algal bloom. A similar, but less pronounced, effect is seen in Lake Tohopekaliga. Personnel stationed at Kissimmee reported that there was an algal bloom on that lake at the time of the EREP pass and that its extent corresponded approximately to that shown on the photograph. Again, the EREP photograph gives information about the extent of the bloom that could not be obtained practically by sampling. ERTS-1 images give some indication of this algal distribution on Lake Griffin in some cases, but are inconclusive.

Hannah, J. W.; Thomas, G. L.; Esparza, F. (principal investigators)

1973-01-01

150

An investigation of submarine groundwater-borne nutrient fluxes to the west Florida shelf and recurrent harmful algal blooms  

USGS Publications Warehouse

A cross-shelf, water-column mass balance of radon-222 (222Rn) provided estimates of submarine groundwater discharge (SGD), which were then used to quantify benthic nutrient fluxes. Surface water and groundwater were collected along a shore-normal transect that extended from Tampa Bay, Florida, across the Pinellas County peninsula, to the 10-m isobath in the Gulf of Mexico. Samples were analyzed for 222Rn and radium-223,224,226 (223,224,226Ra) activities as well as inorganic and organic nutrients. Cross-shore gradients of 222Rn and 223,224,226Ra activities indicate a nearshore source for these isotopes, which mixes with water characterized by low activities offshore. Radon-based SGD rates vary between 2.5 and 15 cm d-1 proximal to the shoreline and decrease offshore. The source of SGD is largely shallow exchange between surface and pore waters, although deeper groundwater cycling may also be important. Enrichment of total dissolved nitrogen and soluble reactive phosphorus in pore water combined with SGD rates results in specific nutrient fluxes comparable to or greater than estuarine fluxes from Tampa Bay. The significance of these fluxes to nearshore blooms of Karenia brevis is highlighted by comparison with prescribed nutrient demands for bloom maintenance and growth. Whereas our flux estimates do not indicate SGD and benthic fluxes as the dominant nutrient source to the harmful algal blooms, SGD-derived loads do narrow the deficit between documented nutrient supplies and bloom demands.

Smith, Christopher G.; Swarzenski, Peter W.

2012-01-01

151

Simulation of algal bloom dynamics in a river with the ensemble Kalman filter  

NASA Astrophysics Data System (ADS)

A simulation framework of algal bloom in a river channel with data assimilation (DA) was developed by employing two numerical models coupled to simulate a watershed and the embedded river channel. The Hydrological Simulation Program-Fortran (HSPF) model simulates flow discharge and water quality from the subwatersheds and the Environmental Fluid Dynamics Code (EFDC) model takes the subwatershed model outputs at the watershed-river confluence points as boundary forcing to simulate river hydrodynamics and water quality. The ensemble Kalman filter (EnKF) was used for assimilation of water quality variables in the framework, linking uncertainty of model simulation and observation. The simulation uncertainty of the HSPF was quantified at the confluence points as simple stochastic error models developed by comparing the model simulation and the observation. The error models reflect uncertainty of both hydrologic and water quality simulation, including uncertainty associated with point and non-point pollution sources in the watershed. The outputs of the HSPF at the confluence points were perturbed with the error models before used in the following ensemble simulation of the EFDC for the main river. DA was conducted with weekly chlorophyll-a data observed along the river to update chlorophyll-a concentrations of the EFDC model grids. The results showed that the model performance was improved by the assimilation: the root mean square error (RMSE) and the mean continuous probability rank score (CPRS) significantly decreased compared to the open-loop simulation. The updated spatial distribution of chlorophyll-a concentration along the river channel was in reasonable agreement with the observation. Although only chlorophyll-a data was involved in the assimilation, phosphate was selected among other water quality variables for update in order to evaluate the effect of chlorophyll-a assimilation on those variables. It turned out that the phosphate simulation was not much improved by the chlorophyll-a data, which was due to weak correlation between the two variables in the model ensemble. Lastly, chlorophyll-a simulation uncertainty in the river attributed to the simulation uncertainty of each variable in the watershed was evaluated. For that, two additional simulations were made, with perturbation only to flow and phosphate respectively at the confluence points. The spread of chlorophyll-a ensemble of each case became significantly narrower than the original case, indicating that the difference is attributed to the uncertainty of the other unperturbed variables.

Kim, Kyunghyun; Park, Minji; Min, Joong-Hyuk; Ryu, Ingu; Kang, Mi-Ri; Park, Lan Joo

2014-11-01

152

Aerial extent, composition, bio-optics and biogeochemistry of a massive under-ice algal bloom in the Arctic  

NASA Astrophysics Data System (ADS)

It has been long thought that coccolithophores are a minor component of the phytoplankton assemblage in Arctic waters, with diatoms typically being more dominant. Little is known about how the phytoplankton communities will change, however, as the Arctic warms. We participated in the 2011 Impacts of Climate on EcoSystems and Chemistry of the Arctic Pacific Environment (ICESCAPE) cruise to the western Arctic, performing a combination of discrete measurements (microscopy, calcification, particulate inorganic carbon (PIC), particulate organic carbon (POC), biogenic silica (BSi)) plus continuous surface bio-optical measurements (absorption, scattering, backscattering and acid-labile backscattering; the latter specific for coccolithophores). Here, we report bio-optical and coccolithophore observations from the massive under-ice algal bloom originally described in Arrigo et al. (2012). The most intense portions of the bloom were centered in cold Winter Water and there was evidence for nitrate drawdown in the top 10-20 m with strong penetration of silicate rich water into the surface waters. Surface chlorophyll a and particulate absorption at 440 nm approached 30 ?g L-1 and 1.0 m-1, respectively. Particulate absorption of detritus (ap at 412 nm) was highly correlated to ap at 440 nm associated with chlorophyll a and slopes of the absorption spectrum showed that both dissolved and particulate absorption at 412 nm exceeded that at 440 nm, with slopes, Sg, of 0.01 nm-1. Colored dissolved organic matter fluorescence (FDOM) was high in the bloom but the relative fluorescence yields were low, characteristic of phytoplankton-produced FDOM (as opposed to terrestrially-produced FDOM). Coccolithophore backscattering was elevated in the under-ice bloom, but it only accounted for 10% of the total particle backscattering, relatively low compared to typical subpolar waters further to the south. Total particle scattering was significantly elevated in the under-ice bloom (values of almost 2 m-1), likely due to the high abundance of large diatoms. Backscattering probabilities in the bloom were ~1%, again characteristic of diatom-dominated populations with few calcifiers. PIC standing stock in the under-ice bloom was low but measurable while biogenic silica molar concentrations were 150 times greater. POC:PON molar ratios were 6-10, characteristic of healthy, rapidly growing phytoplankton, observations further buttressed by carbon:chlorophyll mass ratios of 50-100. Coccolithophore calcification was low but measurable, reaching 1.75 mg C m-3 d-1 in the under-ice bloom, only 0.4% of the photosynthesis. However, the intrinsic carbon-specific growth rate was 0.4 per day for bulk POC and ~1 per day for bulk PIC, close to maximal growth rates expected at these temperatures. SEM and light microscopy results showed mostly diatoms in the bloom. The coccolithophore, Emiliania huxleyi, was observed, providing unequivocal evidence of the presence of coccolithophores in the under-ice algal bloom.

Balch, W. M.; Bowler, B. C.; Lubelczyk, L. C.; Stevens, M. W.

2014-07-01

153

Observations of Atmospheric Nitrogen and Phosphorus Deposition During the Period of Algal Bloom Formation in Northern Lake Taihu, China  

NASA Astrophysics Data System (ADS)

Cyanobacterial blooms in Lake Taihu occurred at the end of April 2007 and had crucial impacts on the livelihood of millions of people living there. Excessive nutrients may promote bloom formation. Atmospheric nitrogen (N) and phosphorus (P) deposition appears to play an important role in algal bloom formation. Bulk deposition and rain water samples were collected respectively from May 1 to November 30, 2007, the period of optimal algal growth, to measure the bulk atmospheric deposition rate, wet deposition rate, and dry deposition rate for total nitrogen (TN; i.e., all species of nitrogen), and total phosphorus (TP; i.e., all species of phosphorus), in northern Lake Taihu, China. The trends of the bulk atmospheric deposition rate for TN and the wet deposition rate for TN showed double peaks during the observation period and distinct influence with plum rains and typhoons. Meanwhile, monthly bulk atmospheric deposition rates for TP showed little influence of annual precipitation. However, excessive rain may lead to high atmospheric N and P deposition rates. In bulk deposition samples, the average percentage of total dissolved nitrogen accounting for TN was 91.2% and changed little with time. However, the average percentage of total dissolved phosphorus accounting for TP was 65.6% and changed substantially with time. Annual bulk atmospheric deposition rates of TN and TP during 2007 in Lake Taihu were estimated to be 2,976 and 84 kg km-2 a-1, respectively. The results showed decreases of 34.4% and 78.7%, respectively, compared to 2002-2003. Annual bulk deposition load of TN for Lake Taihu was estimated at 6,958 t a-1 in 2007 including 4,642 t a-1 of wet deposition, lower than the values obtained in 2002-2003. This may be due to measures taken to save energy and emission control regulations in the Yangtze River Delta. Nevertheless, high atmospheric N and P deposition loads helped support cyanobacterial blooms in northern Lake Taihu during summer and autumn, the period of favorable algal growth.

Zhai, Shuijing; Yang, Longyuan; Hu, Weiping

2009-09-01

154

Formation of a Volunteer Harmful Algal Bloom Network in British Columbia, Canada, Following an Outbreak of Diarrhetic Shellfish Poisoning  

PubMed Central

Evidence for shellfish toxin illness in British Columbia (BC) on the west coast of Canada can be traced back to 1793. For over two hundred years, domestically acquired bivalve shellfish toxin illnesses in BC were solely ascribed to paralytic shellfish poisonings caused by algal blooms of Alexandrium. This changed in 2011, when BC experienced its first outbreak of diarrhetic shellfish poisoning (DSP). As a result of this outbreak, Canada’s first DSP symposium was held in November, 2012, in North Vancouver, BC. Three of the objectives of the symposium were to provide a forum to educate key stakeholders on this emerging issue, to identify research and surveillance priorities and to create a DSP network. The purpose of this paper is to review what is known about shellfish poisoning in BC and to describe a novel volunteer network that arose following the symposium. The newly formed network was designed for industry shellfish growers to identify harmful algae bloom events, so that they may take actions to mitigate the effects of harmful blooms on shellfish morbidity. The network will also inform public health and regulatory stakeholders of potentially emerging issues in shellfish growing areas. PMID:24172211

McIntyre, Lorraine; Cassis, David; Haigh, Nicola

2013-01-01

155

Algicidal Effects of a Novel Marine Pseudoalteromonas Isolate (Class Proteobacteria, Gamma Subdivision) on Harmful Algal Bloom Species of the Genera Chattonella, Gymnodinium, and Heterosigma  

Microsoft Academic Search

During a bacterial survey of the Huon Estuary in southern Tasmania, Australia, we isolated a yellow- pigmented Pseudoalteromonas strain (class Proteobacteria, gamma subdivision), designated strain Y, that had potent algicidal effects on harmful algal bloom species. This organism was identified by 16S rRNA sequencing as a strain with close affinities to Pseudoalteromonas peptidysin. This bacterium caused rapid cell lysis and

CONNIE LOVEJOY; JOHN P. BOWMAN; GUSTAAF M. HALLEGRAEFF

1998-01-01

156

The causes and consequences of algal blooms: the Cladophora glomerata bloom and the Neva Estuary (eastern Baltic Sea).  

PubMed

The biomass dynamics of the green alga Cladophora glomerata was studied in the shallow-water littoral zone of the Neva estuary during May-October of 2003-2005. Additionally, the average production rate of C. glomerata, the biomass of drifting algae and oxygen depletion were examined during period of algae decomposition. Two peaks in C. glomerata biomass, in July and in September, were observed during all years studied, reaching a maximum 300+/-100 g DW m(-2). The primary production of C. glomerata varied from 3.6 to 7.9 g C m(-2) contributing to around 90% of the total primary production in this habitat. From the middle of July to late August the biomass of drifting C. glomerata exceeded the biomass of the attached algae, accounting for 62% of the total algal biomass in shallow areas (0-1m). The hypoxia (a minimum oxygen level of 5% or 0.62 mg dm(-3)) in the water was recorded near shore (to 20-m distance from the shore), negatively influencing the quality of shallow-water habitats. PMID:20347455

Gubelit, Yulia I; Berezina, Nadezhda A

2010-01-01

157

DMS gas transfer coefficients from algal blooms in the Southern Ocean  

NASA Astrophysics Data System (ADS)

Air/sea dimethylsulfide (DMS) fluxes and bulk air/sea gradients were measured over the Southern Ocean in February/March 2012 during the Surface Ocean Aerosol Production (SOAP) study. The cruise encountered three distinct phytoplankton bloom regions, consisting of two blooms with moderate DMS levels, and a high biomass, dinoflagellate-dominated bloom with high seawater DMS levels (>15 nM). Gas transfer coefficients were considerably scattered at wind speeds above 5 m s-1. Bin averaging the data resulted in a linear relationship between wind speed and mean gas transfer velocity consistent with that previously observed. However, the wind speed-binned gas transfer data distribution at all wind speeds is positively skewed. The flux and seawater DMS distributions were also positively skewed, which suggests that eddy covariance-derived gas transfer velocities are consistently influenced by additional, log-normal noise. A~flux footprint analysis was conducted during a transect into the prevailing wind and through elevated DMS levels in the dinoflagellate bloom. Accounting for the temporal/spatial separation between flux and seawater concentration significantly reduces the scatter in computed transfer velocity. The SOAP gas transfer velocity data shows no obvious modification of the gas transfer-wind speed relationship by biological activity or waves. This study highlights the challenges associated with eddy covariance gas transfer measurements in biologically active and heterogeneous bloom environments.

Bell, T. G.; De Bruyn, W.; Marandino, C. A.; Miller, S. D.; Law, C. S.; Smith, M. J.; Saltzman, E. S.

2014-11-01

158

Decomposition of Blue-Green Algal (Cyanobacterial) Blooms in Lake Mendota, Wisconsin  

PubMed Central

Decomposition of natural populations of Lake Mendota phytoplankton dominated by blue-green algae (cyanobacteria) was monitored by using oxygen uptake and disappearance of chlorophyll, algal volume (fluorescence microscopy), particulate protein, particulate organic carbon, and photosynthetic ability (14CO2 up-take). In some experiments, decomposition of 14C-labeled axenic cultures of Anabaena sp. was also measured. In addition to decomposition, mineralization of inorganic nitrogen and phosphorus were followed in some experiments. Decomposition could be described as a first-order process, and the rate of decomposition was similar to that found by others using pure cultures of eucaryotic algae. Nitrogen and phosphorus never limited the decomposition process, even when the lake water was severely limited in soluble forms of these nutrients. This suggests that the bacteria responsible for decomposition can obtain all of their key nutrients for growth from the blue-green algal cells. Filtration of lake water through plankton netting that removed up to 90% of the algal biomass usually did not cause a similar decrease in oxygen demand, suggesting that most of the particulate organic matter used for respiration of the decomposing bacteria was in a small-particle fraction. Short-term oxygen demand correlated well with the particulate chlorophyll concentration of the sample, and a relationship was derived that could be used to predict community respiration of the lake from chlorophyll concentration. Kinetic analysis showed that not all analyzed components disappeared at the same rate during the decomposition process. The relative rates of decrease of the measured parameters were as follows: photosynthetic ability > algal volume > particulate chlorophyll > particulate protein. Decomposition of 14C-labeled Anabaena occurred at similar rates with aerobic epilimnetic water and with anaerobic sediment, but was considerably slower with anaerobic hypolimnetic water. Of the various genera present in the lake, Aphanizomenon and Anabaena were more sensitive to decomposition than was Microcystis. In addition to providing a general picture of the decomposition process, the present work relates to other work on sedimentation to provide a detailed picture of the fate of blue-green algal biomass in a eutrophic lake ecosystem. PMID:16345380

Fallon, Robert D.; Brock, Thomas D.

1979-01-01

159

Yangtze River Water Diversion into Lake Taihu for Algal Bloom Control: Is it Helping or Hurting?  

NASA Astrophysics Data System (ADS)

Harmful algae blooms in Lake Taihu are getting worse every year due to excess nutrients flowing into the water, especially from the northern watershed areas. Impact of blooms on lake's ecosystem, fisheries and drinking water supply to local towns has been severe. Many efforts have been undertaken by both government entities and researchers since 1990 for restoring the lake such as dredging, wetland construction, control of watershed runoff but none has garnered more attention than the water-diversion project. In the water-diversion project, freshwater from the Yangtze River is transferred into the lake via the Wangyuhe River (in the north) and is eventually discharged from the lake via the Taipuhe River (in the south) in an attempt to dilute the polluted water and flush pollutants out of the lake. The effects of water transfer on lake water quality and ecology have drawn great attention because the effectiveness of this project is conflicting. Recent studies suggest that water transfer could only decrease the concentration of phytoplankton but may actually increase concentrations of phosphorus and nitrogen in some areas of the lake where nutrient concentrations are lower than the influent water. In this study, a three dimensional Environmental Fluid Dynamics Code (EFDC) model was used to investigate mass balance and spatial distribution of nutrients (mainly nitrogen and phosphorus) in Lake Taihu before and after transfer.

Acharya, K.; Li, Y.; Tang, C.; Qiu, L.; Yu, Z.

2012-12-01

160

A mechanism for offshore initiation of harmful algal blooms in the coastal Gulf of Maine  

USGS Publications Warehouse

A combination of observations and model results suggest a mechanism by which coastal blooms of the toxic dinoflagellate Alexandrium fundyense can be initiated from dormant cysts located in offshore sediments. The mechanism arises from the joint effects of organism behavior and the wind-driven response of a surface-trapped plume of fresh water originating from riverine sources. During upwelling-favorable winds, the plume thins vertically and extends offshore; downwelling winds thicken the plume and confine it to the nearshore region. In the western Gulf of Maine, the offshore extent of the river plume during upwelling conditions is suffcient to entrain upward-swimming A. fundyense cells germinated from offshore cyst beds. Subsequent downwelling conditions then transport those populations towards the coast.

McGillicuddy, D.J., Jr.; Signell, R.P.; Stock, C.A.; Keafer, B.A.; Keller, M.D.; Hetland, R.D.; Anderson, D.M.

2003-01-01

161

Giantism and its role in the harmful algal bloom species Phaeocystis globosa  

NASA Astrophysics Data System (ADS)

The cosmopolitan alga Phaeocystis globosa forms large blooms in shallow coastal waters off the Viet Nam coast, which impacts the local aquaculture and fishing industries substantially. The unusual feature of this alga is that it forms giant colonies that can reach up to 3cm in diameter. We conducted experiments designed to elucidate the ecophysiological characteristics that presumably favor the development of giant colonies. Satellite images of chlorophyll fluorescence showed that the coastal bloom was initiated in summer and temporally coincident with the onset of monsoonally driven upwelling. While determining the spatial distribution of Phaeocystis was not feasible, we sampled it in the near-shore region. A positive relationship was found between colony size and colonial cell densities, in contrast to results from the North Sea. Mean chlorophyll a concentration per cell was 0.45pgcell-1, lower than in laboratory or temperate systems. The contribution of mucous carbon ranged from 63-95% of the total carbon; furthermore, mucous carbon per unit of colony surface area appeared to decrease with colony size, suggesting that the mucoid sheath became thinner as colonies grew larger. Sinking rates averaged 189md-1, strongly suggesting that giant colonies could only persist in shallow, turbulent environments. No relationship between colony size and sinking rates was observed. DOC concentrations of intracolonial fluid averaged 5940?M, 25 times greater than ambient concentrations. Estimated diffusion coefficients of ions across the mucous envelope were ca. 1.0±0.3×10-7cm2s-1 for colonies with diameters of ca. 1.0cm. In total, the characteristics of the giant colonies suggest that the Vietnamese strain is substantially different from that found in temperate environments, and that it has a number of unusual features that influence its growth and development in coastal Vietnamese waters.

Smith, Walker O.; Liu, Xiao; Tang, Kam W.; DeLizo, Liza M.; Doan, Nhu Hai; Nguyen, Ngoc Lam; Wang, Xiaodong

2014-03-01

162

Mercury uptake within an ice algal community during the spring bloom in first-year Arctic sea ice  

NASA Astrophysics Data System (ADS)

In this study, we examine mercury bioaccumulation by a first-year sea-ice (FYI) algal community in the western Canadian Arctic during the spring of 2008. Total mercury concentration in bottom sea-ice particulate ([PHg]T) ranged 0.004-0.022 µg/g dw and was limited by the amount of mercury available for uptake when the spring bloom commenced. Mercury in ice algae originated from a combination of brine and seawater as sources, while atmospheric mercury depletion events did not appear to significantly contribute as a source in a coupled manner. We show that the bottom sea-ice brine presents a chemically and biologically unique niche from which inorganic Hg makes its way into the food web. Once incorporated into algae, mercury can be transported spatially and trophically within the ecosystem by a range of processes including grazing, resuspension, remineralization, and sedimentation. Ice algae contribute 10-60% of the annual primary production in the Arctic and are thought to become even more productive and abundant under a mild climate change scenario. Replacement of multiyear ice with FYI in the Beaufort Sea alone could result in an additional influx of ˜48 kg/yr of particle bound Hg. Further studies are thus warranted to elucidate mechanisms by which mercury transformation processes and transfer into the Arctic marine food web are impacted by the interaction between sea ice, brine, and seawater.

Burt, Alexis; Wang, Feiyue; Pu?ko, Monika; Mundy, Christopher-John; Gosselin, Michel; Philippe, Benoît; Poulin, Michel; Tremblay, Jean-Éric; Stern, Gary A.

2013-09-01

163

On the Contribution of Subtidal Volume Fluxes to Algal Blooms in Long Island Estuaries  

NASA Astrophysics Data System (ADS)

A bloom of a new picoplankter species Aureococcus anophagefferens occurred in several estuaries in the northeast coast of the U.S.A. in 1985. The phenomenon is believed to be the result of a complex chain of physical-chemical-biological factors. Based on 9 years (1980-88) of tidal data taken at three oceanic locations (Nantucket, Montauk, Atlantic City) and four impacted estuaries on Long Island (Peconic, Shinnecock, Moriches and Great South Bays) it was found that the variance of the sea level fluctuations at subtidal frequencies was much higher than that of the tidal frequencies and highly dependent upon the season. These subtidal variances reached an absolute minimum in the spring of 1985, corresponding to the lowest subtidal volume exchange between shelf waters and the estuaries. Subtidal flushing times were computed taking into account an estimated recirculation parameter. These times were at an absolute high in the spring of 1985; increases of 16, 24 and 12% were determined for Great South Bay, Moriches and Shinnecock respectively. Along with reduced freshwater inflows due to the existing drought, the increased flushing times may have supported a longer permanence of available inorganic nutrient compounds contributing to a favourable environment for the ecological dominance of Aureococcus. The low subtidal sea level fluctuations of 1985 are related to a minimum energy content of the regional wind stress, particularly the alongshore (East-West) component which is responsible for the Ekman pumping into and out of the estuaries.

Vieira, Mário E. C.; Chant, Robert

1993-01-01

164

Algicidal Effects of a Novel Marine Pseudoalteromonas Isolate (Class Proteobacteria, Gamma Subdivision) on Harmful Algal Bloom Species of the Genera Chattonella, Gymnodinium, and Heterosigma  

PubMed Central

During a bacterial survey of the Huon Estuary in southern Tasmania, Australia, we isolated a yellow-pigmented Pseudoalteromonas strain (class Proteobacteria, gamma subdivision), designated strain Y, that had potent algicidal effects on harmful algal bloom species. This organism was identified by 16S rRNA sequencing as a strain with close affinities to Pseudoalteromonas peptidysin. This bacterium caused rapid cell lysis and death (within 3 h) of gymnodinoids (including Gymnodinium catenatum) and raphidophytes (Chattonella marina and Heterosigma akashiwo). It caused ecdysis of armored dinoflagellates (e.g., Alexandrium catenella, Alexandrium minutum, and Prorocentrum mexicanum), but the algal cultures then recovered over the subsequent 24 h. Strain Y had no effect on a cryptomonad (Chroomonas sp.), a diatom (Skeletonema sp.), a cyanobacterium (Oscillatoria sp.), and two aplastidic protozoans. The algicidal principle of strain Y was excreted into the seawater medium and lost its efficacy after heating. Another common bacterial species, Pseudoalteromonas carrageenovora, was isolated at the same time and did not have these algicidal effects. The minimum concentrations of strain Y required to kill G. catenatum were higher than the mean concentrations found in nature under nonbloom conditions. However, the new bacterium showed a chemotactic, swarming behavior that resulted in localized high concentrations around target organisms. These observations imply that certain bacteria could play an important role in regulating the onset and development of harmful algal blooms. PMID:9687434

Lovejoy, Connie; Bowman, John P.; Hallegraeff, Gustaaf M.

1998-01-01

165

Siderophores: The special ingredient to cyanobacterial blooms  

NASA Astrophysics Data System (ADS)

Freshwater lakes provide a number of significant ecological services including clean drinking water, habitat for aquatic biota, and economic benefits. The provision of these ecological services, as well as the health of these aquatic systems, is threatened by the excessive growth of algae, specifically, cyanobacteria. Historically, blooms have been linked to eutrophication but recent occurrences indicate that there are less dramatic changes that induce these blooms. Iron is an essential micronutrient required for specific essential metabolic pathways; however, the amount of biologically available iron in naturally occurring lake ranges from saturation to much lower than cell transport affinities. To assist in the modulation of iron availabilities, cyanobacteria in culture produce low molecular weight compounds that function in an iron binding and acquisition system; nevertheless, this has yet to be confirmed in naturally occurring lakes. This project explored the relationship of P, N and in particular, Fe, in the promotion of cyanobacteria harmful algal blooms in 30 natural freshwater lakes located in and around the Elk Island National Park, Alberta. It is hypothesized that cyanobacteria produce and utilize iron chelators called siderophores in low Fe and nitrogen (N) conditions, creating a competitive advantage over other algae in freshwater lakes. Lakes were selected to represent a range of iron availability to explore the nutrient composition of lakes that propagated cyanobacteria harmful algal blooms (cHABs) compared to lakes that did not. Lake water was analyzed for nutrients, microbial composition, siderophore concentration, and toxin concentration. Modifications were made to optimize the Czaky and Arnow tests for hydroxamate- and catecholate-type siderophores, respectively, for field conditions. Preliminary results indicate the presence of iron-binding ligands (0.11-2.34 mg/L) in freshwater lakes characterized by widely ranging Fe regimes (0.04-2.74 mg/L). Furthermore, the concentration of iron-binding ligands was found to have a positive correlation to presence of cyanobacteria concentration, indicating a potential relationship between Fe, siderophores, and cyanobacteria. This project works to improve the understanding of freshwater cyanobacteria growth dynamics by investigating the physiological and biochemical processes leading to cHABs. The importance of this project lies in the understanding of elementary nutrient requirements in all algae and how cyanobacteria are able to access low concentration pools and subsequently bloom over other algal species. Investigating the nutrient regimes that stimulate siderophore production and the subsequent production of potentially toxic cyanobacteria blooms is important for lake management and preservation, specifically in the eutrophic and hypereutrophic freshwater lakes of Alberta.

Du, Xue; Creed, Irena; Trick, Charles

2013-04-01

166

The laboratory mouse in routine food safety testing for marine algal biotoxins and harmful algal bloom toxin research: past, present and future.  

PubMed

Mouse bioassays have been a mainstay for detecting harmful concentrations of marine algal toxins in shellfish for over 70 years. Routine monitoring involves intraperitoneal injection of shellfish extracts into mice; shellfish contaminated with algal toxins are thus identified by mortality in exposed mice. With the advent of alternative test methods to detect and quantify specific algal toxins has come increasing criticism of enduring use of mouse bioassays for shellfish safety testing. However, the complete replacement of shellfish safety mouse bioassays by chemical, antibody-based, and functional assays has been and will continue to be a gradual process for various reasons, including skills availability and instrument costs for chromatography-based toxin monitoring. Mouse bioassays for shellfish safety testing do not comply with modern standards for laboratory animal welfare, specifically the requirement in published official methods for death as a test outcome. Mouse bioassays for algal biotoxins in shellfish, as well as fundamental algal toxin research endeavors using in vivo models, are amenable to revision and refinement from a humane endpoints perspective. Regulated hypothermia may be a useful and easily acquired nonlethal toxicological endpoint; objective determination of neuromuscular blockade may allow algal neurotoxin testing and research to enter the domain of humane endpoints evaluation. Relinquishing reliance on subjective test endpoints, including death, will likely also deliver collateral improvements in assay variability and sensitivity. PMID:24830147

Stewart, Ian; McLeod, Catherine

2014-01-01

167

Understanding interannual, decadal level variability in paralytic shellfish poisoning toxicity in the Gulf of Maine: The HAB Index  

NASA Astrophysics Data System (ADS)

A major goal in harmful algal bloom (HAB) research has been to identify mechanisms underlying interannual variability in bloom magnitude and impact. Here the focus is on variability in Alexandrium fundyense blooms and paralytic shellfish poisoning (PSP) toxicity in Maine, USA, over 34 years (1978-2011). The Maine coastline was divided into two regions - eastern and western Maine, and within those two regions, three measures of PSP toxicity (the percent of stations showing detectable toxicity over the year, the cumulative amount of toxicity per station measured in all shellfish (mussel) samples during that year, and the duration of measurable toxicity) were examined for each year in the time series. These metrics were combined into a simple HAB Index that provides a single measure of annual toxin severity across each region. The three toxin metrics, as well as the HAB Index that integrates them, reveal significant variability in overall toxicity between individual years as well as long-term, decadal patterns or regimes. Based on different conceptual models of the system, we considered three trend formulations to characterize the long-term patterns in the Index - a three-phase (mean-shift) model, a linear two-phase model, and a pulse-decline model. The first represents a “regime shift” or multiple equilibria formulation as might occur with alternating periods of sustained high and low cyst abundance or favorable and unfavorable growth conditions, the second depicts a scenario of more gradual transitions in cyst abundance or growth conditions of vegetative cells, and the third characterizes a ”sawtooth” pattern in which upward shifts in toxicity are associated with major cyst recruitment events, followed by a gradual but continuous decline until the next pulse. The fitted models were compared using both residual sum of squares and Akaike's Information Criterion. There were some differences between model fits, but none consistently gave a better fit than the others. This statistical underpinning can guide efforts to identify physical and/or biological mechanisms underlying the patterns revealed by the HAB Index. Although A. fundyense cyst survey data (limited to 9 years) do not span the entire interval of the shellfish toxicity records, this analysis leads us to hypothesize that major changes in the abundance of A. fundyense cysts may be a primary factor contributing to the decadal trends in shellfish toxicity in this region. The HAB Index approach taken here is simple but represents a novel and potentially useful tool for resource managers in many areas of the world subject to toxic HABs.

Anderson, Donald M.; Couture, Darcie A.; Kleindinst, Judith L.; Keafer, Bruce A.; McGillicuddy, Dennis J., Jr.; Martin, Jennifer L.; Richlen, Mindy L.; Hickey, J. Michael; Solow, Andrew R.

2014-05-01

168

Harmful algal blooms (HABs), dissolved organic matter (DOM), and planktonic microbial community dynamics at a near-shore and a harbour station influenced by upwelling (SW Iberian Peninsula)  

Microsoft Academic Search

The surface microalgal community, including harmful species, dissolved organic matter (DOM), and bacterial and viral populations were studied during an annual cycle (November 2007–October 2008) in a Near-shore (NS) and a Harbour (H) station located in an upwelling area (Sagres, SW Iberian Peninsula). The higher water residence time, water stability and shallowness of harbours in comparison with open waters likely

Sofia Loureiro; Albert Reñé; Esther Garcés; Jordi Camp; Dolors Vaqué

2011-01-01

169

Applications of MODIS Fluorescence Line Height Measurements to Monitor Water Quality Trends and Algal Bloom Activity in Coastal and Estuarine Waters  

NASA Astrophysics Data System (ADS)

Recent advances in satellite and airborne remote sensing, such as improvements in sensor and algorithm calibrations and atmospheric correction procedures have provided for increased coverage of remote-sensing, ocean color products for coastal regions. In particular, for the Moderate Resolution Imaging Spectrometer (MODIS), calibration updates, improved aerosol retrievals, and new aerosol models have led to improved atmospheric correction algorithms for turbid waters and have improved the retrieval of ocean-color. This has opened the way for studying coastal ocean phenomena and processes at finer spatial scales. Human population growth and changes in coastal management practices have brought about significant changes in the concentrations of organic and inorganic, particulate and dissolved substances entering the coastal ocean. There is increasing concern that these inputs have led to declines in water quality and increases in local concentrations of phytoplankton, which could result in harmful algal blooms. In two case studies we present improved and validated MODIS coastal observations of fluorescence line height (FLH) to: (1) assess trends in water quality for Tampa Bay, Florida; and (2) illustrate seasonal and annual variability of algal bloom activity in Monterey Bay, California, as well as document estuarine/riverine plume induced red tide events. In a comprehensive analysis of long term (2003-2011) in situ monitoring data and imagery from Tampa Bay, we assess the validity of the MODIS FLH product against chlorophyll-a and a suite of water quality parameters taken in a variety of conditions throughout this large, optically complex estuarine system. A systematic analysis of sampling sites throughout the bay illustrates that the correlations between FLH and in situ chlorophyll-a are influenced by water quality parameters of total nitrogen, total phosphorous, turbidity and biological oxygen demand. Sites that correlated well with satellite imagery were in depths greater than seven meters and were located over five kilometers from shore. Satellite FLH estimates show improving water quality from 2003-2007 with a slight decline up through 2011. Dinoflagellate blooms in Monterey Bay, California have recently increased in frequency and intensity. Nine years of MODIS FLH observations are used to describe the annual and seasonal variability of bloom activity within the Bay. Three classes of MODIS algorithms were correlated against in situ chlorophyll measurements. The FLH algorithm provided the most robust estimate of bloom activity. Elevated concentrations of phytoplankton were evident during the months of August-November, a period during which increased occurrences of dinoflagellate blooms have been observed in situ. Seasonal patterns of FLH show the on- and offshore movement of areas of high phytoplankton biomass between oceanographic seasons. Higher concentrations of phytoplankton are also evident in the vicinity of the land-based nutrient sources and outflows, and cyclonic bay-wide circulation transports these nutrients to a northern Bay bloom incubation region. Both of these case studies illustrate the utility of improved MODIS FLH observations in supporting management decisions in coastal and estuarine waters.

Fischer, A.; Ryan, J. P.; Moreno-Madriñán, M. J.

2012-12-01

170

Spatiotemporal changes in the genetic diversity of harmful algal blooms caused by the toxic dinoflagellate Alexandrium minutum.  

PubMed

Organisms with sexual and asexual reproductive systems benefit from both types of reproduction. Sexual recombination generates new combinations of alleles, whereas clonality favours the spread of the fittest genotype through the entire population. Therefore, the rate of sexual vs. clonal reproduction has a major influence on the demography and genetic structure of natural populations. We addressed the effect of reproductive system on populations of the dinoflagellate Alexandrium minutum. More specifically, we monitored the spatiotemporal genetic diversity during and between bloom events in two estuaries separated by 150 km for two consecutive years. An analysis of population genetic patterns using microsatellite markers revealed surprisingly high genotypic and genetic diversity. Moreover, there was significant spatial and temporal genetic differentiation during and between bloom events. Our results demonstrate that (i) interannual genetic differentiation can be very high, (ii) estuaries are partially isolated during bloom events and (iii) genetic diversity can change rapidly during a bloom event. This rapid genetic change may reflect selective effects that are nevertheless not strong enough to reduce allelic diversity. Thus, sexual reproduction and/or migration may regularly erase any genetic structure produced within estuaries during a bloom event. PMID:24330231

Dia, A; Guillou, L; Mauger, S; Bigeard, E; Marie, D; Valero, M; Destombe, C

2014-02-01

171

Long-term evaluation of three satellite ocean color algorithms for identifying harmful algal blooms (Karenia brevis) along the west coast of Florida: A matchup assessment  

PubMed Central

We present a simple algorithm to identify Karenia brevis blooms in the Gulf of Mexico along the west coast of Florida in satellite imagery. It is based on an empirical analysis of collocated matchups of satellite and in situ measurements. The results of this Empirical Approach is compared to those of a Bio-optical Technique – taken from the published literature – and the Operational Method currently implemented by the NOAA Harmful Algal Bloom Forecasting System for K. brevis blooms. These three algorithms are evaluated using a multi-year MODIS data set (from July, 2002 to October, 2006) and a long-term in situ database. Matchup pairs, consisting of remotely-sensed ocean color parameters and near-coincident field measurements of K. brevis concentration, are used to assess the accuracy of the algorithms. Fair evaluation of the algorithms was only possible in the central west Florida shelf (i.e. between 25.75°N and 28.25°N) during the boreal Summer and Fall months (i.e. July to December) due to the availability of valid cloud-free matchups. Even though the predictive values of the three algorithms are similar, the statistical measure of success in red tide identification (defined as cell counts in excess of 1.5 × 104 cells L?1) varied considerably (sensitivity—Empirical: 86%; Bio-optical: 77%; Operational: 26%), as did their effectiveness in identifying non-bloom cases (specificity—Empirical: 53%; Bio-optical: 65%; Operational: 84%). As the Operational Method had an elevated frequency of false-negative cases (i.e. presented low accuracy in detecting known red tides), and because of the considerable overlap between the optical characteristics of the red tide and non-bloom population, only the other two algorithms underwent a procedure for further inspecting possible detection improvements. Both optimized versions of the Empirical and Bio-optical algorithms performed similarly, being equally specific and sensitive (~70% for both) and showing low levels of uncertainties (i.e. few cases of false-negatives and false-positives: ~30%)—improved positive predictive values (~60%) were also observed along with good negative predictive values (~80%). PMID:22180667

Carvalho, Gustavo A.; Minnett, Peter J.; Banzon, Viva F.; Baringer, Warner; Heil, Cynthia A.

2011-01-01

172

Evaluation of internal loading and water level changes: implications for phosphorus, algal production, and nuisance blooms in Kabetogama Lake, Voyageurs National Park, Minnesota  

USGS Publications Warehouse

Hydrologic manipulations have the potential to exacerbate or remediate eutrophication in productive reservoirs. Dam operations at Kabetogama Lake, Minnesota, were modified in 2000 to restore a more natural water regime and improve water quality. The US Geological Survey and National Park Service evaluated nutrient, algae, and nuisance bloom data in relation to changes in Kabetogama Lake water levels. Comparison of the results of this study to previous studies indicates that chlorophyll a concentrations have decreased, whereas total phosphorus (TP) concentrations have not changed significantly since 2000. Water and sediment quality data were collected at Voyageurs National Park during 2008–2009 to assess internal phosphorus loading and determine whether loading is a factor affecting TP concentrations and algal productivity. Kabetogama Lake often was mixed vertically, except for occasional stratification measured in certain areas, including Lost Bay in the northeastern part of Kabetogama Lake. Stratification, higher bottom water and sediment nutrient concentrations than in other parts of the lake, and phosphorus release rates estimated from sediment core incubations indicated that Lost Bay is one of several areas that may be contributing to internal loading. Internal loading of TP is a concern because increased TP may cause excessive algal growth including potentially toxic cyanobacteria.

Christensen, Victoria G.; Maki, Ryan P.; Kiesling, Richard L.

2013-01-01

173

Toxicity of harmful cyanobacterial blooms to bream and roach.  

PubMed

Aquatic ecosystems are facing increasing environmental pressures, leading to an increasing frequency of cyanobacterial Harmful Algal Blooms (cHABs) that have emerged as a worldwide concern due to their growing frequency and their potential toxicity to the fauna that threatens the functioning of ecosystems. Cyanobacterial blooms raise concerns due to the fact that several strains produce potent bioactive or toxic secondary metabolites, such as the microcystins (MCs), which are hepatotoxic to vertebrates. These strains of cyanobacteria may be potentially toxic to fish via gastrointestinal ingestion and also by direct absorption of the toxin MC from the water. The purpose of our study was to investigate toxic effects observed in fish taken from several lakes in the Ile-de-France region, where MCs-producing blooms occur. This study comprises histological studies and the measurement of MC concentrations in various organs. The histological findings are similar to those obtained following laboratory exposure of medaka fish to MCs: hepatic lesions predominate and include cell lysis and cell detachment. MC concentrations in the organs revealed that accumulation was particularly high in the digestive tract and the liver, which are known to be classical targets of MCs. In contrast concentrations were very low in the muscles. Differences in the accumulation of MC variants produced by blooms indicate that in order to more precisely evaluate the toxic potential of a specific bloom it is necessary not only to consider the concentration of toxins, but also the variants produced. PMID:23732128

Trinchet, Isabelle; Cadel-Six, Sabrina; Djediat, Chakib; Marie, Benjamin; Bernard, Cécile; Puiseux-Dao, Simone; Krys, Sophie; Edery, Marc

2013-09-01

174

Boundary influences on HAB phytoplankton ecology in a stratification-enhanced upwelling shadow  

NASA Astrophysics Data System (ADS)

Coastal marine ecosystems are profoundly influenced by processes that originate from their boundaries. These include fluid boundaries—with the atmosphere, oceanic boundary currents and terrestrial aquatic systems, as well as solid boundaries—with the seafloor and coast. Phytoplankton populations transfer complexly interacting boundary influences into the biosphere. In this contribution, we apply data from an ocean observing and modeling system to examine boundary influences driving phytoplankton ecology in Monterey Bay, CA, USA. The study was focused on species that may cause harmful algal blooms (HABs). During September-October 2010, autonomous molecular analytical devices were moored at two locations characterized by different degrees of stratification and exposure to upwelling dynamics. The time-series revealed multiple transitions in local HAB phytoplankton communities, involving diatoms (Pseudo-nitzschia spp.), dinoflagellates (Alexandrium catenella), and raphidophytes (Heterosigma akashiwo). Observational and model results showed that the biological transitions were closely related to environmental changes that resulted from a variety of boundary processes—responses of oceanic circulation to wind forcing, influxes of different water types that originated outside the bay, and emergence of strongly stratified nearshore water into the greater bay. Boundary processes were further implicated at patch scales. High-resolution mapping and sampling of a phytoplankton-enriched patch were conducted in a Lagrangian framework using autonomous underwater vehicles. These highly resolved measurements showed that small-scale spatial patterns in the toxicity of Pseudo-nitzschia populations were related to the coupling of resuspended sediments from the bottom boundary layer to the surface mixed layer.

Ryan, J. P.; McManus, M. A.; Kudela, R. M.; Lara Artigas, M.; Bellingham, J. G.; Chavez, F. P.; Doucette, G.; Foley, D.; Godin, M.; Harvey, J. B. J.; Marin, R.; Messié, M.; Mikulski, C.; Pennington, T.; Py, F.; Rajan, K.; Shulman, I.; Wang, Z.; Zhang, Y.

2014-03-01

175

Spatiotemporal Distribution of Harmful Algal Flora in the Tropical Estuarine Complex of Goa, India  

PubMed Central

Mandovi and Zuari estuarine complex is monsoon-influenced estuaries located along the central west coast of India. During the past few years, there has been an increase in nutrient loading specially during monsoonal runoff which is responsible for the growth of harmful algal flora. To understand occurrence and distribution of harmful algal blooms species, daily/alternate day samplings were carried out in Mandovi and Zuari estuaries during 2007-2008 and 2008-2009 periods, respectively, comprising of monsoon (June–November) and nonmonsoon (December–May). In Mandovi, total 54 HAB species with 49 in monsoon and 36 during nonmonsoon period were reported. In Zuari, total 46 HAB species with 38 in monsoon and 41 were reported during nonmonsoon period. Bray-Curtis cluster analysis based on log-transformed phytoplankton density detected seven well-defined groups revealing spatiotemporal variability. The density of the dominant harmful algal species was significantly positively correlated with nutrients, but negatively correlated with salinity. The results of the study indicate that monsoon plays an important role in occurrence and distribution of harmful algal species having direct correlation with salinity variations and nutrient loading. PMID:22629154

Pednekar, Suraksha M.; Prabhu Matondkar, S. G.; Kerkar, Vijaya

2012-01-01

176

Detection of Critical LUCC Indices and Sensitive Watershed Regions Related to Lake Algal Blooms: A Case Study of Taihu Lake.  

PubMed

Taihu Lake in China has suffered from severe eutrophication over the past 20 years which is partly due to significant land use/cover change (LUCC). There is an increasing need to detect the critical watershed region that significantly affects lake water degradation, which has great significance for environmental protection. However, previous studies have obtained conflicting results because of non-uniform lake indicators and inadequate time periods. To identify the sensitive LUCC indices and buffer distance regions, three lake divisions (Meiliang Lake, Zhushan Lake and Western Coastal region) and their watershed region within the Taihu Lake basin were chosen as study sites, the algal area was used as a uniform lake quality indicator and modeled with LUCC indices over the whole time series. Results showed that wetland (WL) and landscape index such as Shannon diversity index (SHDI) appeared to be sensitive LUCC indices when the buffer distance was less than 5 km, while agricultural land (AL) and landscape fragmentation (Ci) gradually became sensitive indices as buffer distances increased to more than 5 km. For the relationship between LUCC and lake algal area, LUCC of the WC region seems to have no significant effect on lake water quality. Conversely, LUCC within ML and ZS region influenced algal area of corresponding lake divisions greatly, while the most sensitive regions were found in 3 km to 5 km, rather than the whole catchment. These results will be beneficial for the further understanding of the relationship between LUCC and lake water quality, and will provide a practical basis for the identification of critical regions for lake. PMID:25642691

Lin, Chen; Ma, Ronghua; Su, Zhihu; Zhu, Qing

2015-01-01

177

Seasonal variation in benthic community oxygen demand: A response to an ice algal bloom in the Beaufort Sea, Canadian Arctic?  

NASA Astrophysics Data System (ADS)

Understanding pathways of carbon cycling on Arctic shelves is critical if we are to evaluate the potential effects of climate change on these systems. We investigated the relationship between ice algal standing stock and benthic respiration between January and July 2004 at a time series station in the southeastern Beaufort Sea. Both ice algal chlorophyll a and benthic sediment oxygen demand showed > 10-fold increases from between March and April. While some of the increase in oxygen demand can be attributed to bacteria and meio-fauna, most was due to the activities of macroinfauna. We also observed a trend toward lower sediment pigment content during the pulse in benthic carbon remineralization. While chl a sedimentation also increased by a factor of 7 during this period, fluxes were not sufficient to provide for the increased carbon demand. We suggest that sedimenting ice algae provided a cue for increased benthic activity, and that direct consumption of ice algae and increased oxygen availability in the sediment due to bioturbation by epifaunal organisms led to the enhancement in respiration rates. Seasonal patterns in primary productivity and the activity of resident epifaunal and infaunal communities are, thus, important factors in determining carbon cycling patterns on Arctic shelves.

Renaud, Paul E.; Riedel, Andrea; Michel, Christine; Morata, Nathalie; Gosselin, Michel; Juul-Pedersen, Thomas; Chiuchiolo, Amy

2007-08-01

178

Algal blooms and "Marine snow": Mechanisms that enhance preservation of organic carbon in ancient fine-grained sediments  

USGS Publications Warehouse

Combined petographic and geochemical methods are used to investigate the microfabrics present in thin sections prepared from representative organic carbon-rich mudstones collected from three successions (the Kimmeridge Clay Formation, the Jet Rock Member of the Whitby Mudstone Formation, and the pebble shale and Hue Shale). This study was initiated to determine how organic carbon-rich materials were being delivered to the sediment-water interface, and what happened to them after deposition, prior to deep burial. Analyses of the fabrics present shows that they exhibit many common attributes. In particular they are all: (1) highly heterogeneous on the scale of a thin section, (2) organized into thin beds (< 10 mm thick) composed mainly of mineral mixtures of fine-grained siliciclastic detritus and carbonate materials, and (3) contain significant concentrations of organic carbon, much of which is organized into laminasets that contain abundant organomineralic aggregates and pellets. In addition, framboidal pyrite (range of sizes from < 20 urn to < 1 ??m) and abundant agglutinated foraminifers are present in some units. The individual beds are commonly sharp-based and overlain by thin, silt lags. The tops of many of the beds have been homogenized and some regions of the pelleted laminasets contain small horizontal burrows. The organomineralic aggregates present in these mudstones are interpreted to be ancient examples of marine snow. This marine snow likely formed in the water column, particularly during phytoplankton blooms, and was then transported rapidly to the seafloor. The existence of the thin beds with homogenized tops and an in-situ infauna indicates that between blooms there was sufficient oxygen and time for a mixed layer to develop as a result of sediment colonization by diminutive organisms using either aerobic or dysaerobic metabolic pathways. These textures suggest that the constituents of these mudstones were delivered neither as a continuous rain of sediment nor were the bottom waters persistently anoxic. In addition, the presence of thin lags and sharp-based beds suggests that the seafloor was being episodically reworked during deposition. These fabrics indicate that conditions in the water columns and at the seafloors while these rocks were being deposited were very dynamic, and episodic fluxes of high concentrations of organic carbon to the seafloor, during phytoplankton blooms, likely enhanced preservation of organic carbon. Copyright ?? 2010, SEPM (Society for Sedimentary Geology).

Macquaker, J.H.S.; Keller, M.A.; Davies, S.J.

2010-01-01

179

Concurrent Exposure of Bottlenose Dolphins (Tursiops truncatus) to Multiple Algal Toxins in Sarasota Bay, Florida, USA  

PubMed Central

Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA), the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs) of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX) produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA). Over a ten-year study period (2000–2009) we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009) with 36% of all animals testing positive for brevetoxin (n?=?118) and 53% positive for DA (n?=?83) with several individuals (14%) testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p?=?0.001) and eosinophil (p<0.001) counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health. PMID:21423740

Twiner, Michael J.; Fire, Spencer; Schwacke, Lori; Davidson, Leigh; Wang, Zhihong; Morton, Steve; Roth, Stephen; Balmer, Brian; Rowles, Teresa K.; Wells, Randall S.

2011-01-01

180

Short-range forecast of Shershnevskoie (South Ural) water-storage algal blooms: preliminary results of predictors' choosing and membership functions' construction  

NASA Astrophysics Data System (ADS)

Short-range forecasting of algal blooms in drinking water reservoirs and other waterbodies is an actual element of water treatment system. Particularly, Shershnevskoie reservoir - the source of drinking water for Chelyabinsk city (South Ural region of Russia) - is exposed to interannual, seasonal and short-range fluctuations of blue-green alga Aphanizomenon flos-aquae and other dominant species abundance, which lead to technological problems and economic costs and adversely affect the water treatment quality. Whereas the composition, intensity and the period of blooms affected not only by meteorological seasonal conditions but also by ecological specificity of waterbody, that's important to develop object-oriented forecasting, particularly, search for an optimal number of predictors for such forecasting. Thereby, firstly fuzzy logic and fuzzy artificial neural network patterns for blue-green alga Microcystis aeruginosa (M. aeruginosa) blooms prediction in nearby undrained Smolino lake were developed. These results subsequently served as the base to derive membership functions for Shernevskoie reservoir forecasting patterns. Time series with the total lenght about 138-159 days of dominant species seasonal abundance, water temperature, cloud cover, wind speed, mineralization, phosphate and nitrate concentrations were obtained through field observations held at Lake Smolino (Chelyabinsk) in the warm season of 2009 and 2011 with time resolution of 2-7 days. The cross-correlation analysis of the data revealed the potential predictors of M. aeruginosa abundance quasi-periodic oscillations: green alga Pediastrum duplex (P. duplex) abundance and mineralization for 2009, P. duplex abundance, water temperature and concentration of nitrates for 2011. According to the results of cross-correlation analysis one membership function "P. duplex abundance" and one rule linking M. aeruginosa and P. duplex abundances were set up for database of 2009. Analogically, for database of 2011 three rules, linking membership functions of temperature, P. duplex abundance, nitrate concentration and M. aeruginosa abundance were set up. Developed fuzzy logic rules were good to predict M. aeruginosa intense outbreaks. For ANN method of forecasting specially written program was used to train the fuzzy artificial neural network on number of input selected predictors' values and output predicted factor's values to set up the predictive rules and membership functions automatically. As a result, two models based on mineralization and P. duplex abundance were developed for 2009. For 2011 four patterns were developed, the best result was obtained for model based on temperature and P. duplex abundance. Developed methods of forecasting were applied to predict outbreaks of Aphanizomenon flos-aquae and M. aeruginosa abundance in Shershnevskoie reservoir. For this purpose long-term data of chemical parameters, measured once in a month, data of dominant species abundance, measured fifth in a week and data of turbidity, water color, alkalinity, pH, obtained each day, were analyzed. Based on these empirical data significant factors were determined, membership functions were set up and preliminary models for Shershnevskoie reservoir were developed. As expected, these models differ significantly from developed for Smolino lake ones and should be tested on new data sets.

Gayazova, Anna; Abdullaev, Sanjar

2014-05-01

181

SinterHab  

NASA Astrophysics Data System (ADS)

This project describes a design study for a core module on a Lunar South Pole outpost, constructed by 3D printing technology with the use of in-situ resources and equipped with a bio-regenerative life support system. The module would be a hybrid of deployable (CLASS II) and in-situ built (CLASS III) structures. It would combine deployable membrane structures and pre-integrated rigid elements with a sintered regolith shell for enhanced radiation and micrometeorite shielding. The closed loop ecological system would support a sustainable presence on the Moon with particular focus on research activities. The core module accommodates from four to eight people, and provides laboratories as a test bed for development of new lunar technologies directly in the environment where they will be used. SinterHab also includes an experimental garden for development of new bio-regenerative life support system elements. The project explores these various concepts from an architectural point-of-view particularly, as they constitute the building, construction and interior elements. The construction method for SinterHab is based on 3D printing by sintering of the lunar regolith. Sinterator robotics 3D printing technology proposed by NASA JPL enables construction of future generations of large lunar settlements with little imported material and the use of solar energy. The regolith is processed, placed and sintered by the Sinterator robotics system which combines the NASA ATHLETE and the Chariot remotely controlled rovers. Microwave sintering creates a rigid structure in the form of walls, vaults and other architectural elements. The interior is coated with a layer of inflatable membranes inspired by the TransHab project. The life-support system is mainly bio-regenerative and several parts of the system are intrinsically multifunctional and serve more than one purpose. The plants for food production are also an efficient part of atmosphere revitalization and water treatment. Moreover, the plants will be used as a "winter garden" for psychological and recreational purposes. The water in the revitalization system has a multifunctional use, as radiation shielding in the safe-haven habitat core. The garden module creates an artificial outdoor environment mitigating the notion of confinement on the lunar surface. Fiber optics systems and plasma lamps are used for transmission of natural and artificial light into the interior.

Rousek, Tomáš; Eriksson, Katarina; Doule, Ond?ej

2012-05-01

182

Algal toxins and reverse osmosis desalination operations: laboratory bench testing and field monitoring of domoic acid, saxitoxin, brevetoxin and okadaic acid.  

PubMed

The occurrence and intensity of harmful algal blooms (HABs) have been increasing globally during the past few decades. The impact of these events on seawater desalination facilities has become an important topic in recent years due to enhanced societal interest and reliance on this technology for augmenting world water supplies. A variety of harmful bloom-forming species of microalgae occur in southern California, as well as many other locations throughout the world, and several of these species are known to produce potent neurotoxins. These algal toxins can cause a myriad of human health issues, including death, when ingested via contaminated seafood. This study was designed to investigate the impact that algal toxin presence may have on both the intake and reverse osmosis (RO) desalination process; most importantly, whether or not the naturally occurring algal toxins can pass through the RO membrane and into the desalination product. Bench-scale RO experiments were conducted to explore the potential of extracellular algal toxins contaminating the RO product. Concentrations exceeding maximal values previously reported during natural blooms were used in the laboratory experiments, with treatments comprised of 50 ?g/L of domoic acid (DA), 2 ?g/L of saxitoxin (STX) and 20 ?g/L of brevetoxin (PbTx). None of the algal toxins used in the bench-scale experiments were detectable in the desalinated product water. Monitoring for intracellular and extracellular concentrations of DA, STX, PbTx and okadaic acid (OA) within the intake and desalinated water from a pilot RO desalination plant in El Segundo, CA, was conducted from 2005 to 2009. During the five-year monitoring period, DA and STX were detected sporadically in the intake waters but never in the desalinated water. PbTx and OA were not detected in either the intake or desalinated water. The results of this study demonstrate the potential for HAB toxins to be inducted into coastal RO intake facilities, and the ability of typical RO operations to effectively remove these toxins. PMID:23079130

Seubert, Erica L; Trussell, Shane; Eagleton, John; Schnetzer, Astrid; Cetini?, Ivona; Lauri, Phil; Jones, Burton H; Caron, David A

2012-12-01

183

A shift in the dominant toxin-producing algal species in central California alters phycotoxins in food webs  

USGS Publications Warehouse

In California, the toxic algal species of primary concern are the dinoflagellate Alexandrium catenella and members of the pennate diatom genus Pseudo-nitzschia, both producers of potent neurotoxins that are capable of sickening and killing marine life and humans. During the summer of 2004 in Monterey Bay, we observed a change in the taxonomic structure of the phytoplankton community-the typically diatom-dominated community shifted to a red tide, dinoflagellate-dominated community. Here we use a 6-year time series (2000-2006) to show how the abundance of the dominant harmful algal bloom (HAB) species in the Bay up to that point, Pseudo-nitzschia, significantly declined during the dinoflagellate-dominated interval, while two genera of toxic dinoflagellates, Alexandrium and Dinophysis, became the predominant toxin producers. This change represents a shift from a genus of toxin producers that typically dominates the community during a toxic bloom, to HAB taxa that are generally only minor components of the community in a toxic event. This change in the local HAB species was also reflected in the toxins present in higher trophic levels. Despite the small contribution of A. catenella to the overall phytoplankton community, the increase in the presence of this species in Monterey Bay was associated with an increase in the presence of paralytic shellfish poisoning (PSP) toxins in sentinel shellfish and clupeoid fish. This report provides the first evidence that PSP toxins are present in California's pelagic food web, as PSP toxins were detected in both northern anchovies (Engraulis mordax) and Pacific sardines (Sardinops sagax). Another interesting observation from our data is the co-occurrence of DA and PSP toxins in both planktivorous fish and sentinel shellfish. We also provide evidence, based on the statewide biotoxin monitoring program, that this increase in the frequency and abundance of PSP events related to A. catenella occurred not just in Monterey Bay, but also in other coastal regions of California. Our results demonstrate that changes in the taxonomic structure of the phytoplankton community influences the nature of the algal toxins that move through local food webs and also emphasizes the importance of monitoring for the full suite of toxic algae, rather than just one genus or species. ?? 2008 Elsevier B.V.

Jester, R.; Lefebvre, K.; Langlois, G.; Vigilant, V.; Baugh, K.; Silver, M.W.

2009-01-01

184

Factors determining the dynamics of toxic blooms of Alexandrium minutum during a 10-year study along the shallow southwestern Mediterranean coasts  

NASA Astrophysics Data System (ADS)

Many blooms of the toxic dinoflagellate Alexandrium minutum have been recorded since 1990 in the Gulf of Gabes (southwestern Mediterranean Sea). To understand the determining factors of bloom formation, we studied the distribution of A. minutum in relation to environmental factors in samples taken at shallow sandy (<1 m) beach stations and a lagoon between 1997 and 2006. This was accompanied by laboratory experiments to identify A. minutum. The species forms harmful algal blooms (HABs) in stations subjected to anthropogenic eutrophication and in confined lagoons, living under conditions of varying salinity which gives it a unique opportunity to broaden its physiological tolerance and increase its colonisation potential. Increases in phosphorus appear to be more important than nitrogen or temperature in the control of A. minutum. The stations sampled all along the coast present specific hydrographic properties (shallowness, turbulence) suggesting that factors other than temperature and nutrients influence Alexandrium distribution, the exception being Boughrara Lagoon where the species developed in accordance with published data. Our findings and their interpretations indicate that the mechanism of the sudden A. minutum blooms along the nearshore of the Gulf of Gabes was complex and differed from that of true coastal ecosystems.

Abdenadher, Moufida; Hamza, Asma; Fekih, Wafa; Hannachi, Imen; Zouari Bellaaj, Amel; Bradai, Mohamed Nejmeddine; Aleya, Lotfi

2012-06-01

185

A Quantitative Assessment of the Role of the Parasite Amoebophrya in the Termination of Alexandrium fundyense Blooms within a Small Coastal Embayment  

PubMed Central

Parasitic dinoflagellates of the genus Amoebophrya infect free-living dinoflagellates, some of which can cause harmful algal blooms (HABs). High prevalence of Amoebophrya spp. has been linked to the decline of some HABs in marine systems. The objective of this study was to evaluate the impact of Amoebophrya spp. on the dynamics of dinoflagellate blooms in Salt Pond (MA, USA), particularly the harmful species Alexandrium fundyense. The abundance of Amoebophrya life stages was estimated 3–7 days per week through the full duration of an annual A. fundyense bloom using fluorescence in situ hybridization coupled with tyramide signal amplification (FISH- TSA). More than 20 potential hosts were recorded including Dinophysis spp., Protoperidinium spp. and Gonyaulax spp., but the only dinoflagellate cells infected by Amoebophrya spp. during the sampling period were A. fundyense. Maximum A. fundyense concentration co-occurred with an increase of infected hosts, followed by a massive release of Amoebophrya dinospores in the water column. On average, Amoebophrya spp. infected and killed ?30% of the A. fundyense population per day in the end phase of the bloom. The decline of the host A. fundyense population coincided with a dramatic life-cycle transition from vegetative division to sexual fusion. This transition occurred after maximum infected host concentrations and before peak infection percentages were observed, suggesting that most A. fundyense escaped parasite infection through sexual fusion. The results of this work highlight the importance of high frequency sampling of both parasite and host populations to accurately assess the impact of parasites on natural plankton assemblages. PMID:24324668

Velo-Suárez, Lourdes; Brosnahan, Michael L.; Anderson, Donald M.; McGillicuddy, Dennis J.

2013-01-01

186

HARMFUL ALGAL BLOOMS IN THE GREAT LAKES NOAA Center of Excellence for Great Lakes and Human Health 4840 S. State Rd. Ann Arbor, MI 48108 734-741-2235  

E-print Network

HABs. Blue-green algae are actually bacteria (cyanobacteria) which are able to photosynthesize, hence, 2009 (Photo: T. Archer). #12;Toxins Produced by blue green algae Blue-green algae can produce a wide

187

Maribacter thermophilus sp. nov., isolated from an algal bloom in the intertidal zone of Qingdao sea area, China, and an emended description of the genus Maribacter.  

PubMed

A novel facultatively anaerobic, Gram-negative bacterium, designated strain HT7-2T, was isolated from Ulva prolifera collected from the intertidal zone of Qingdao sea area, China, during its bloom. Cells were rod-shaped (1.9-3.5 × 0.4-0.6 ?m), non-sporulating, and motile by gliding. Strain HT7-2T was able to grow at 4-50 °C (optimum 40-42 °C), pH 5.5-8.5 (optimum pH 7.0), 0-8% (w/v) NaCl (optimum 2-3%) and 0.5-10% (w/v) sea salts (optimum 2.5%). The genomic DNA G+C content was 38.8 mol%. The phylogenetic analysis based on 16S rRNA gene sequences revealed that strain HT7-2T belonged to the genus Maribacter with sequence similarity values of 94.5-96.6%, and was most closely related to Maribacter aestuarii GY20T (96.6%). Chemotaxonomic analysis showed that the main isoprenoid quinone was MK-6 and the major fatty acids were iso-C15:0 and unknown ECL 13.565. The polar lipids of strain HT7-2T consisted of one phosphatidylethanolamine (PE), four unidentified lipids (L1~4) and one unidentified aminolipid (AL). On the basis of the phenotypic, phylogenetic and chemotaxonomic characteristics, strain HT7-2T (= CGMCC 1.12207T = JCM 18466T) is concluded to represent a novel species of the genus Maribacter, for which the name Maribacter thermophilus sp. nov. is proposed. An emended description of the genus Maribacter is also proposed. PMID:25269849

Hu, Jing; Yang, Qi-Qi; Ren, Yi; Zhang, Wen-Wu; Zheng, Gang; Sun, Cong; Pan, Jie; Zhu, Xu-Fen; Zhang, Xin-Qi; Wu, Min

2014-09-30

188

Stochastic Forecasting of Algae Blooms in Lakes  

SciTech Connect

We consider the development of harmful algae blooms (HABs) in a lake with uncertain nutrients inflow. Two general frameworks, Fokker-Planck equation and the PDF methods, are developed to quantify the resultant concentration uncertainty of various algae groups, via deriving a deterministic equation of their joint probability density function (PDF). A computational example is examined to study the evolution of cyanobacteria (the blue-green algae) and the impacts of initial concentration and inflow-outflow ratio.

Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

2013-01-15

189

DEVELOPMENT AND APPLICATION OF A FIBER OPTIC ARRAY SYSTEM FOR DETECTION AND ENUMERATION OF POTENTIALLY TOXIC CYANOBACTERIA  

EPA Science Inventory

Harmful algal blooms (HABs) have become a serious threat to freshwater and marine waters worldwide, impacting humans, animals, and aquatic ecosystems. In freshwater, many cyanobacterial blooms (cyanoHABs) produce neurotoxic, hepatotoxic, dermatotoxic, or other bioactive compo...

190

Mapping Cyanobacteria Blooms in Lake Champlain at Multiple ScaleMapping Cyanobacteria Blooms in Lake Champlain at Multiple Scales:s: QuickBirdQuickBird and MERIS Satellite Dataand MERIS Satellite Data  

E-print Network

Mapping Cyanobacteria Blooms in Lake Champlain at Multiple ScaleMapping Cyanobacteria Blooms in Lake Champlain at Multiple Scales:s: QuickBirdQuickBird and MERIS Satellite Dataand MERIS Satellite Data Harmful algal blooms in Lake Champlain (VT-NY-QC) are an increasingly serious concern. Such blooms

Morrissey, Leslie A.

191

Global warming and cyanobacterial harmful algal blooms  

Microsoft Academic Search

The Earth and the oceans have warmed significantly over the past four decades, providing evidence that the Earth is undergoing\\u000a long-term climate change. Increasing temperatures and changing rainfall patterns have been documented. Cyanobacteria have\\u000a a long evolutionary history, with their first occurrence dating back at least 2.7 billion years ago. Cyanobacteria often dominated\\u000a the oceans after past mass extinction events.

Valerie J Paul

192

Global warming and cyanobacterial harmful algal blooms.  

PubMed

The Earth and the oceans have warmed significantly over the past four decades, providing evidence that the Earth is undergoing long-term climate change. Increasing temperatures and changing rainfall patterns have been documented. Cyanobacteria have a long evolutionary history, with their first occurrence dating back at least 2.7 billion years ago. Cyanobacteria often dominated the oceans after past mass extinction events. They evolved under anoxic conditions and are well adapted to environmental stress including exposure to UV, high solar radiation and temperatures, scarce and abundant nutrients. These environmental conditions favor the dominance of cyanobacteria in many aquatic habitats, from freshwater to marine ecosystems. A few studies have examined the ecological consequences of global warming on cyanobacteria and other phytoplankton over the past decades in freshwater, estuarine, and marine environments, with varying results. The responses of cyanobacteria to changing environmental patterns associated with global climate change are important subjects for future research. Results of this research will have ecological and biogeochemical significance as well as management implications. PMID:18461772

Paul, Valerie J

2008-01-01

193

Harmful Algal Blooms: Paralytic Shellfish Poisoning  

NSDL National Science Digital Library

This University of Maryland SeaGrant web page explores outbreaks of paralytic shellfish poisoning (PSP), a problem on both the East and West coasts of the US that is caused by several closely related species in the genus Alexandrium. The page explores the underlying physical mechanisms and localization of PSP outbreaks, as well as economic impact.

Jacobs, Dan

194

Harmful Algal Blooms: Amnesic Shellfish Poisoning  

NSDL National Science Digital Library

This University of Maryland SeaGrant web page discusses amnesic shellfish poisoning (ASP), also known as domoic acid poisoning (DAP). The page discusses the production of domoic acid by the diatom Pseudo-nitzschia, geographic locations of detection, and economic impacts.

Kane, Andrew; Jacobs, Dan; Seagrant, University O.

195

Fueling Future with Algal Genomics  

SciTech Connect

Algae constitute a major component of fundamental eukaryotic diversity, play profound roles in the carbon cycle, and are prominent candidates for biofuel production. The US Department of Energy Joint Genome Institute (JGI) is leading the world in algal genome sequencing (http://jgi.doe.gov/Algae) and contributes of the algal genome projects worldwide (GOLD database, 2012). The sequenced algal genomes offer catalogs of genes, networks, and pathways. The sequenced first of its kind genomes of a haptophyte E.huxleyii, chlorarachniophyte B.natans, and cryptophyte G.theta fill the gaps in the eukaryotic tree of life and carry unique genes and pathways as well as molecular fossils of secondary endosymbiosis. Natural adaptation to conditions critical for industrial production is encoded in algal genomes, for example, growth of A.anophagefferens at very high cell densities during the harmful algae blooms or a global distribution across diverse environments of E.huxleyii, able to live on sparse nutrients due to its expanded pan-genome. Communications and signaling pathways can be derived from simple symbiotic systems like lichens or complex marine algae metagenomes. Collectively these datasets derived from algal genomics contribute to building a comprehensive parts list essential for algal biofuel development.

Grigoriev, Igor

2012-07-05

196

Chemical defense of a marine cyanobacterial bloom  

Microsoft Academic Search

A popular Guam beach experienced a temporary closure in May 1994 due to the simultaneous occurrence of a blue-green algal bloom and a massive die-off of juvenile rabbitfishes (Siganus argenteus (Quoy and Gaimard) and Siganus spinus (Linnaeus). The microbial assemblage was composed primarily of the marine cyanobacterium Schizothrix calcicola (Ag.) Gomont with sparsely distributed strands of Lyngbya majuscula Gomont. Palatability

Dale G. Nagle; Valerie J. Paul

1998-01-01

197

Localization and Tracking of Submerged Phytoplankton Bloom Patches by an Autonomous Underwater Vehicle  

NASA Astrophysics Data System (ADS)

Observing plankton in their drifting frame of reference permits effective studies of marine ecology from the perspective of microscopic life itself. By minimizing variation caused simply by advection, observations in a plankton-tracking frame of reference focus measurement capabilities on the processes that influence the life history of populations. Further, the patchy nature of plankton populations motivates use of sensor data in real-time to resolve patch boundaries and adapt observing resources accordingly. We have developed capabilities for population-centric plankton observation and sampling by autonomous underwater vehicles (AUVs). Our focus has been on phytoplankton populations, both because of their ecological significance - as the core of the oceanic food web and yet potentially harmful under certain bloom conditions, as well as the accessibility of their signal to simple optical sensing. During the first field deployment of these capabilities in 2010, we tracked a phytoplankton patch containing toxigenic diatoms and found that their toxicity correlated with exposure to resuspended sediments. However, this first deployment was labor intensive as the AUV drove in a pre-programmed pattern centered around a patch-marking drifter; it required a boat deployment of the patch-marking drifter and required full-time operators to periodically estimate of the position of the patch with respect to the drifter and adjust the AUV path accordingly. In subsequent field experiments during 2011 and 2012, the Tethys-class long-range AUVs ran fully autonomous patch tracking algorithms which detected phytoplankton patches and continually updated estimates of each patch center by driving adaptive patterns through the patch. Iterations of the algorithm were generated to overcome the challenges of tracking advecting and evolving patches while minimizing human involvement in vehicle control. Such fully autonomous monitoring will be necessary to perform long-term in-situ observation of the full growth and decay cycle of bloom patches. Doing so will enhance our understanding of the temporal and spatial dynamics of bloom patches and the observable conditions that lead to bloom formation, ultimately improving our ability to predict the evolution of harmful algal blooms (HABs) and provide warnings for the fishing and tourism industries.

Godin, M. A.; Ryan, J. P.; Zhang, Y.; Bellingham, J. G.

2012-12-01

198

Mitigating harmful cyanobacterial blooms in a human- and climatically-impacted world.  

PubMed

Bloom-forming harmful cyanobacteria (CyanoHABs) are harmful from environmental, ecological and human health perspectives by outcompeting beneficial phytoplankton, creating low oxygen conditions (hypoxia, anoxia), and by producing cyanotoxins. Cyanobacterial genera exhibit optimal growth rates and bloom potentials at relatively high water temperatures; hence, global warming plays a key role in their expansion and persistence. CyanoHABs are regulated by synergistic effects of nutrient (nitrogen:N and phosphorus:P) supplies, light, temperature, vertical stratification, water residence times, and biotic interactions. In most instances, nutrient control strategies should focus on reducing both N and P inputs. Strategies based on physical, chemical (nutrient) and biological manipulations can be effective in reducing CyanoHABs; however, these strategies are largely confined to relatively small systems, and some are prone to ecological and environmental drawbacks, including enhancing release of cyanotoxins, disruption of planktonic and benthic communities and fisheries habitat. All strategies should consider and be adaptive to climatic variability and change in order to be effective for long-term control of CyanoHABs. Rising temperatures and greater hydrologic variability will increase growth rates and alter critical nutrient thresholds for CyanoHAB development; thus, nutrient reductions for bloom control may need to be more aggressively pursued in response to climatic changes globally. PMID:25517134

Paerl, Hans W

2014-01-01

199

Mitigating Harmful Cyanobacterial Blooms in a Human- and Climatically-Impacted World  

PubMed Central

Bloom-forming harmful cyanobacteria (CyanoHABs) are harmful from environmental, ecological and human health perspectives by outcompeting beneficial phytoplankton, creating low oxygen conditions (hypoxia, anoxia), and by producing cyanotoxins. Cyanobacterial genera exhibit optimal growth rates and bloom potentials at relatively high water temperatures; hence, global warming plays a key role in their expansion and persistence. CyanoHABs are regulated by synergistic effects of nutrient (nitrogen:N and phosphorus:P) supplies, light, temperature, vertical stratification, water residence times, and biotic interactions. In most instances, nutrient control strategies should focus on reducing both N and P inputs. Strategies based on physical, chemical (nutrient) and biological manipulations can be effective in reducing CyanoHABs; however, these strategies are largely confined to relatively small systems, and some are prone to ecological and environmental drawbacks, including enhancing release of cyanotoxins, disruption of planktonic and benthic communities and fisheries habitat. All strategies should consider and be adaptive to climatic variability and change in order to be effective for long-term control of CyanoHABs. Rising temperatures and greater hydrologic variability will increase growth rates and alter critical nutrient thresholds for CyanoHAB development; thus, nutrient reductions for bloom control may need to be more aggressively pursued in response to climatic changes globally. PMID:25517134

Paerl, Hans W.

2014-01-01

200

CyanoHAB occurrence and water irrigation cyanotoxin contamination: ecological impacts and potential health risks.  

PubMed

The world-wide occurrence of harmful cyanobacteria blooms "CyanoHAB" in fresh and brackish waters creates problems for all life forms. During CyanoHAB events, toxic cyanobacteria produce cyanotoxins at high levels that can cause chronic and sub-chronic toxicities to animals, plants and humans. Cyanotoxicity in eukaryotes has been mainly focused on animals, but during these last years, data, related to cyanotoxin (mainly microcystins, MCs) impact on both aquatic and terrestrials crop plants irrigated by water containing these toxins, have become more and more available. This last cited fact is gaining importance since plants could in a direct or indirect manner contribute to cyanotoxin transfer through the food chain, and thus constitute a potent health risk source. The use of this contaminated irrigation water can also have an economical impact which appears by a reduction of the germination rate of seeds, and alteration of the quality and the productivity of crop plants. The main objective of this work was to discuss the eventual phytotoxicity of cyanotoxins (microcystins) as the major agricultural impacts induced by the use of contaminated water for plant irrigation. These investigations confirm the harmful effects (ecological, eco-physiological, socio-economical and sanitary risk) of dissolved MCs on agricultural plants. Thus, cyanotoxin phytotoxicity strongly suggests a need for the surveillance of CyanoHAB and the monitoring of water irrigation quality as well as for drinking water. PMID:22069535

Saqrane, Sana; Oudra, Brahim

2009-12-01

201

An overview of historical harmful algae blooms outbreaks in the Arabian Seas.  

PubMed

Harmful algae blooms (HABs), often composed of oceanic plants called phytoplankton, are potentially harmful to the marine life, water quality, human health, and desalination plants, a chief source of potable water in the Arabian Gulf. The last decade has seen a noticeable increase in the frequency of HAB outbreaks in the Arabian Seas. This increase is mainly caused by the unprecedented economic growth in the region. The increased human activities in the region have added more stress to the marine environment and contributed to the changes observed in the properties of the marine ecosystem: high temperature and salinity, high evaporation rates, limited freshwater inflow, shallow nature, pollution. However, very few studies that cover the HAB outbreaks, causes, impacts and biological characteristics over the region have been published. This work presents a comprehensive overview of historical HAB outbreaks recorded in the region, and investigate their causes and impact, and seasonal variability. PMID:25038981

Al Shehhi, Maryam R; Gherboudj, Imen; Ghedira, Hosni

2014-09-15

202

Detection of surface algal blooms using the newly developed algorithm surface algal bloom index (SABI)  

E-print Network

chlorophyll concentration using optical satellite sensors like MODIS and MERIS. The production of chlorophyll occurs at the highest reflectance slope between the maximum absorption in the red due to the surrounding-tidal vegetation like seagrass. This algorithm was specifically modelled to adapt to the marine habitat through its

Quartly, Graham

203

Mar. Drugs 2013, 11, 830-841; doi:10.3390/md11030830 Marine Drugs  

E-print Network

in Diarrhetic Shellfish Poisoning (DSP) toxins produced during Harmful Algal Blooms (HABs), representing of potentially harmful biotoxins that are accumulated throughout the food chain. Among HAB biotoxins, Diarrhetic Shellfish Poisoning (DSP) toxins are especially predominant across European coasts, causing alterations

Eirin Lopez, Jose Maria

204

BIOMARKER LIPIDS IN RED TIDE (GYMNODINIUM BREVE) BLOOMS ALONG THE NORTHWEST FLORIDA COAST  

EPA Science Inventory

The ability to characterize phytoplankton communities and algal blooms using lipids as biomarkers requires knowledge of their distribution and taxonomic significance. Such an approach would have application, for example, in distinguishing and tracking certain dinoflagellates suc...

205

Copepod life cycle adaptations and success in response to phytoplankton spring bloom phenology  

Microsoft Academic Search

In a seasonal environment, the timing of reproduction is usually scheduled to maximize the survival of offspring. Within deep water bodies, the phytoplankton spring bloom provides a short time window of high food quantity and quality for herbivores. The onset of algal bloom development, however, varies strongly from year to year due to interannual variability in meteorological conditions. Furthermore, the

HANNO S EEBENS; U LRICH

2009-01-01

206

Decadal-Scale Changes of Dinoflagellates and Diatoms in the Anomalous Baltic Sea Spring Bloom  

Microsoft Academic Search

The algal spring bloom in the Baltic Sea represents an anomaly from the winter-spring bloom patterns worldwide in terms of frequent and recurring dominance of dinoflagellates over diatoms. Analysis of approximately 3500 spring bloom samples from the Baltic Sea monitoring programs revealed (i) that within the major basins the proportion of dinoflagellates varied from 0.1 (Kattegat) to >0.8 (central Baltic

Riina Klais; Timo Tamminen; Anke Kremp; Kristian Spilling; Kalle Olli; Dirk Steinke

2011-01-01

207

Human Impacts on Catchments  

NSDL National Science Digital Library

This website offers an explanation of red tide and other harmful algal blooms (HABs). It briefly explains what algal blooms are and what causes them. Designed for educatiors, the site also provides activity ideas and links to other HAB-related sites.

Boards, South A.

208

Harmful algae blooms removal from fresh water with modified vermiculite.  

PubMed

Vermiculite and vermiculite modified with hydrochloric acid were investigated to evaluate their flocculation efficiencies in freshwater containing harmful algae blooms (HABs) (Microcystis aeruginosa). Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, converted fluorescence microscope, plasma-atomic emission spectrometry, and Zetasizer were used to study the flocculation mechanism of modified vermiculite. It was found that the vermiculite modified with hydrochloric acid could coagulate algae cells through charge neutralization, chemical bridging, and netting effect. The experimental results show that the efficiency of flocculation can be notably improved by modified vermiculite. Ninety-eight per cent of algae cells in algae solution could be removed within 10 min after the addition ofmodified vermiculite clay. The method that removal of HABs with modified vermiculite is economical with high efficiency, and more research is needed to assess their ecological impacts before using in practical application. PMID:24600873

Miao, Chunguang; Tang, Yi; Zhang, Hong; Wu, Zhengyan; Wang, Xiangqin

2014-01-01

209

In situ observation of harmful dinoflagellate bloom in the eastern coast of Kyushu, Japan  

NASA Astrophysics Data System (ADS)

Oita coast, where is in the eastern coast of Kyushu, Japan, is a richly fish aquaculture area. However, sometimes harmful algal blooms occur in this region, especially harmful dinoflagellates blooms, and cultured fish mortality occurs. Ocean color remote sensing is expected as a useful tool to reduce the financial damage of harmful algal blooms. However, ocean color data is low accuracy in the coastal region because colored dissolved organic matter and suspended solid are dominant. More optical data of harmful algal blooms are required because there are few data in harmful algal blooms. The field observation was conducted to understand the inherent optical property of harmful dinoflagellate bloom in the eastern coast of Oita prefecture on April and August 2013. Chlorophyll-a maximum (>24 mg m^-3) was observed in the subsurface layer on April 2013. The dominant phytoplankton species in this chlorophyll-a maximum layer was dinoflagellate Cochlodinium polykrikoides (>300 cells ml^-1) and early stage of the bloom was formed. Peak of the remote sensing reflectance was near 565nm due to strong phytoplankton absorption within 400 ~ 500 nm domain from the subsurface bloom layer. Moreover, high phytoplankton absorption coefficient was observed at the shorter wavelength (< 400nm). This strong absorption might be due to mycosporine-like amino acids, which absorb the UV (Kahru and Mitchell, 1998). And this subsurface C. polykrikoides bloom was detected by using dinoflagellate bloom detection algorithm, which is a simpler new satellite remote sensing-based harmful algal blooms detection method for JAXA's GCOM-C/SGLI (Siswanto et al., 2013). However, detection of the dinoflagellate Karenia mikimotoi bloom by using the algorithm on August 2013 was difficult as colored dissolved organic matter and detritus absorptions were high. Although the algorithm could detect the early stage of C. polycrikoides bloom, the algorithm improvement to detect the harmful algal blooms in the case II water is thus highly required. This research is part of the combined research between Japan Aerospace Exploration Agency and National Research Institute of Fisheries science.

Yamaguchi, Hisashi; Murakami, Hirishi; Miyamura, Kazuyoshi; Siawanto, Eko; Kobayashi, Hiroshi; Ishizaka, Joji

2014-05-01

210

Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics  

E-print Network

Harmful algal blooms (HABs) cause significant economic and ecological damage worldwide. Despite considerable efforts, a comprehensive understanding of the factors that promote these blooms has been lacking, because the ...

Bertrand, Erin Marie

211

Algal biofuels.  

PubMed

The world is facing energy crisis and environmental issues due to the depletion of fossil fuels and increasing CO2 concentration in the atmosphere. Growing microalgae can contribute to practical solutions for these global problems because they can harvest solar energy and capture CO2 by converting it into biofuel using photosynthesis. Microalgae are robust organisms capable of rapid growth under a variety of conditions including in open ponds or closed photobioreactors. Their reduced biomass compounds can be used as the feedstock for mass production of a variety of biofuels. As another advantage, their ability to accumulate or secrete biofuels can be controlled by changing their growth conditions or metabolic engineering. This review is aimed to highlight different forms of biofuels produced by microalgae and the approaches taken to improve their biofuel productivity. The costs for industrial-scale production of algal biofuels in open ponds or closed photobioreactors are analyzed. Different strategies for photoproduction of hydrogen by the hydrogenase enzyme of green algae are discussed. Algae are also good sources of biodiesel since some species can make large quantities of lipids as their biomass. The lipid contents for some of the best oil-producing strains of algae in optimized growth conditions are reviewed. The potential of microalgae for producing petroleum related chemicals or ready-make fuels such as bioethanol, triterpenic hydrocarbons, isobutyraldehyde, isobutanol, and isoprene from their biomass are also presented. PMID:23605290

Razeghifard, Reza

2013-11-01

212

In situ detrimental impacts of Prorocentrum donghaiense blooms on zooplankton in the East China Sea.  

PubMed

Large-scale algal blooms of the dinoflagellate Prorocentrum donghaiense have occurred frequently in the East China Sea (ECS) in recent decades. However, its impacts on the zooplankton in situ are still under not well understood. During a spring P. donghaiense bloom (April-May 2013) along the northern coast of Fujian Province (120°-121°30?E, 26°30?-28°N), we found that the bloom decreased the abundance of copepods and had no significant effect on chaetognaths and small jellyfish. However, the abundance of small jellyfish increased over the course of the study. The zooplankton community changed from being copepod and small jellyfish- to small jellyfish-dominated during the bloom. In the bloom areas, the copepod Calanus sinicus showed higher mortality and lower egg production rates (EPR) than those in the non-bloom areas. The results suggested that P. donghaiense blooms had detrimental effects on the structure of zooplankton community and the recruitments of C. sinicus. PMID:25242234

Lin, Jia-Ning; Yan, Tian; Zhang, Qing-Chun; Wang, Yun-Feng; Liu, Qing; Zhou, Ming-Jiang

2014-11-15

213

35. Photocopy of blueprint (original in HABS files) Thomas W. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

35. Photocopy of blueprint (original in HABS files) Thomas W. Lamb, Architect July 15, 1926 GRAND FOYER INTERIOR DETAILS - B. F. Keith Memorial Theatre, 539 Washington Street, Boston, Suffolk County, MA

214

SpaceHab 1 maintenance experiment  

NASA Technical Reports Server (NTRS)

The SpaceHab 1 flight on STS-57 served as a test platform for evaluation of two space station payloads. The first payload evaluated a space station maintenance concept using a sweep signal generator and a 48-channel logic analyzer to perform fault detection and isolation. Crew procedures files, test setup diagram files, and software to configure the test equipment were created on the ground and uplinked on the astronauts' voice communication circuit to perform tests in flight. In order to use these files, the portable computer was operated in a multi-window configuration. The test data transmitted to the ground allowing the ground staff to identify the cause of the fault and provide the crew with the repair procedures and diagrams. The crew successfully repaired the system under test. The second payload investigated hand soldering and de-soldering of standard components on printed circuit (PC) boards in zero gravity. It also used a new type of intra-vehicular foot restraints which uses the neutral body posture in zero-g to provide retention of the crew without their conscious attention.

Bohannon, Jackie W.

1994-01-01

215

Harmful Algae Page  

NSDL National Science Digital Library

Concise information on harmful algal blooms (HABs) and their effect on humans and other organisms. Site features maps of past cases of toxins and deaths associated with HABs, a spreadsheet discussing which toxins are associated with what animals, and a figure outlining the effects of HABs on the food web. Includes information on HAB funding, workshops, and conference proceedings, as well as links to additional HAB information.

216

Ice-associated phytoplankton blooms in the southeastern Bering Sea  

NASA Astrophysics Data System (ADS)

Ice-associated phytoplankton blooms in the southeastern Bering Sea can critically impact the food web structure, from lower tropic level production to marine fisheries. By coupling pelagic and sea ice algal components, our 1-D ecosystem model successfully reproduced the observed ice-associated blooms in 1997 and 1999 at the NOAA/PMEL mooring M2. The model results suggest that the ice-associated blooms were seeded by sea ice algae released from melting sea ice. For an ice-associated bloom to grow and reach the typical magnitude of phytoplankton bloom in the region, ice melting-resulted low-salinity stratification must not be followed by a strong mixing event that would destroy the stratification. The ice-associated blooms had little impacts on the annual primary production, but had significant impacts in terms of shifting phytoplankton species, and the timing and magnitude of the bloom. These changes, superimposed on a gradual ecosystem shift attributed to global warming, can dramatically alter the Bering Sea ecosystem.

Jin, Meibing; Deal, Clara; Wang, Jia; Alexander, Vera; Gradinger, Rolf; Saitoh, Sei-ichi; Iida, Takahiro; Wan, Zhenwen; Stabeno, Phyllis

2007-03-01

217

DLR-EnviHab - A closed environmental Habitat  

NASA Astrophysics Data System (ADS)

Closed habitats intended for different purposes like confinement studies, life in extreme environments (Antarctica) and as simulation testbeds for complex closed life support systems have been built and achieved different degrees of closure. Those that were built in preparation of space missions oriented themselves on the need of a crew of astronauts during a long term mission in Space, on Mars or Moon. At DLR in Cologne, a modular approach is followed to build a closed environmental habitat for scientific and medical studies, the DLR-EnviHab. This modular structure of the EnviHab is designed to include humans as integral part in a bioregenerative life support system, and allows a step-wise realization of the project, ensuring useful results for a wide field of scientific research during each phase. The DLR-EnviHab provides a platform for international and interdisciplinary research and the development of innovative solutions for cultivation and habitation on Earth as well as for long term space or planetary missions. By the inclusion of humans as integral component of the system, medical research areas including physiological and psychological health and rehabilitation as well as environmental research and monitoring and modelling of coupled and controlled systems are addressed in EnviHab. Results of the research conducted in the individual and combined EnviHab modules will also contribute to most urgent issues like water(recycling) management, food management, pollution/waste management and atmosphere(air) management. In addition, EnviHab contributes to public education and outreach with the open visible and partly accessible structure, an exhibition and an explanatory module.

Rabbow, E.; Koch, B.; Rettberg, P.; Horneck, G.; Graef, P.; Gerzer, R.

218

Macroalgal blooms alter community structure and primary productivity in marine ecosystems.  

PubMed

Eutrophication, coupled with loss of herbivory due to habitat degradation and overharvesting, has increased the frequency and severity of macroalgal blooms worldwide. Macroalgal blooms interfere with human activities in coastal areas, and sometimes necessitate costly algal removal programmes. They also have many detrimental effects on marine and estuarine ecosystems, including induction of hypoxia, release of toxic hydrogen sulphide into the sediments and atmosphere, and the loss of ecologically and economically important species. However, macroalgal blooms can also increase habitat complexity, provide organisms with food and shelter, and reduce other problems associated with eutrophication. These contrasting effects make their overall ecological impacts unclear. We conducted a systematic review and meta-analysis to estimate the overall effects of macroalgal blooms on several key measures of ecosystem structure and functioning in marine ecosystems. We also evaluated some of the ecological and methodological factors that might explain the highly variable effects observed in different studies. Averaged across all studies, macroalgal blooms had negative effects on the abundance and species richness of marine organisms, but blooms by different algal taxa had different consequences, ranging from strong negative to strong positive effects. Blooms' effects on species richness also depended on the habitat where they occurred, with the strongest negative effects seen in sandy or muddy subtidal habitats and in the rocky intertidal. Invertebrate communities also appeared to be particularly sensitive to blooms, suffering reductions in their abundance, species richness, and diversity. The total net primary productivity, gross primary productivity, and respiration of benthic ecosystems were higher during macroalgal blooms, but blooms had negative effects on the productivity and respiration of other organisms. These results suggest that, in addition to their direct social and economic costs, macroalgal blooms have ecological effects that may alter their capacity to deliver important ecosystem services. PMID:24890042

Lyons, Devin A; Arvanitidis, Christos; Blight, Andrew J; Chatzinikolaou, Eva; Guy-Haim, Tamar; Kotta, Jonne; Orav-Kotta, Helen; Queirós, Ana M; Rilov, Gil; Somerfield, Paul J; Crowe, Tasman P

2014-09-01

219

Physical Mechanisms Driving Harmful Algal Blooms Along the Texas Coast  

E-print Network

, formerly known as Gymnodinium breve, in the Gulf of Mexico. K. brevis is harmful because it produces brevetoxin, a ladder-frame polyether that acts as a potent neurotoxin in vertebrates. K. brevis commonly causes fish kills, respiratory irritation...

Ogle, Marcus 1982-

2012-12-12

220

Cyanobacterial Harmful Algal Blooms: Chapter 20: Analytical Methods Workgroup Report  

Microsoft Academic Search

The topic of exposure assessment overlaps with other topic areas of this workshop. It includes considerations of establishment of long term monitoring and event response, sampling protocols, development and standardization of organism and toxin assays, funding mechanisms, and public outreach. The development of a coordinated infrastructure (funding, human resources, and facilities, materials and equipment) is key to successfully addressing the

Armah de la Cruz; Parke Rublee; James Hungerford; Paul Zimba; Steven Wilhelm; Jussi Meriluoto; Kathy Echols; Michael Meyer; Gerard Stelma; Rosemonde Mandeville; Linda Lawton; Kaarina Sivonen; Ambrose Furey

2008-01-01

221

Chapter 11: Global warming and cyanobacterial harmful algal blooms  

Microsoft Academic Search

The Earth and the oceans have warmed significantly over the past four decades, providing evidence that the Earth is undergoing long-term climate change. Increasing temperatures and changing rainfall patterns have been documented. Cyanobacteria have a long evolutionary history, with their first occurrence dating back at least 2.7 billion years ago. Cyanobacteria often dominated the oceans after past mass extinction events.

Valerie J Paul

222

Harmful Algal Blooms, Hypoxia & Climate Change: West Coast Region Introduction  

E-print Network

and populations with cascading effects upon larger animal populations as salmon, smelt, and rockfish. Program with our Federal, State, and academic partners, CSCOR has investigated the factors that regulate

223

THE CAUSES AND CONTROL OF ALGAL BLOOMS IN CLEAR LAKE  

E-print Network

Camp, Student Assistant, UCD Heath J. Carney, Research Associate, UCD Bruce Follansbee, Graduate Group District and its Director Bill Davidson and Scientists Art Colwell (now Director), Norm Anderson and David

Richerson, Peter J.

224

HARMFUL ALGAL BLOOMS AS INDICATORS OF ECOSYSTEM CONDITION  

EPA Science Inventory

There are approximately 40 species of microalgae inhabiting coastal waters in the Gulf of Mexico that produce or potentially can produce biotoxins that negatively impact aquatic ecosystems, human health, and local economics. While nutrient enrichment and reduced water quality may...

225

Combined effect of predatory zooplankton and allelopathic aquatic macrophytes on algal suppression.  

PubMed

The present study evaluated the combined effects of four typical predatory zooplankton and allelopathic aquatic macrophytes on algal control in a microcosm system. It would determine the effects of diverse species and biological restoration on the growth of harmful water-bloom microalgae in great lakes polluted by excess nutrients. It was found that the mixtures of each zooplankton and the floating plant Nymphoides peltatum had stronger inhibitory effects on harmful water-bloom microalgae than the individual species in clean or eutrophic water bodies. In addition, a community of four zooplankton types had a synergistic effect on algal inhibition. Algal suppression by the zooplankton community was enhanced significantly when the macrophyte was co-cultured in the microcosm. Furthermore, Chlorella pyrenoidosa was more susceptible than Microcystis aeruginosa when exposed to grazing by zooplankton and the allelopathic potential of the macrophyte. Algal inhibition was also weaker in eutrophic conditions compared with the control. These findings indicate that diverse species may enhance algal inhibition. Therefore, it is necessary to restore biological diversity and rebuild an ecologically balanced food chain or web to facilitate the control of harmful algal blooms in eutrophic lakes. PMID:25409583

Zuo, Shengpeng; Wan, Kun; Ma, Sumin

2015-01-01

226

9. View east along Rockland Road, George Murphy House (HABS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. View east along Rockland Road, George Murphy House (HABS No. DE-284) in left background and northern estate wall and tree lines to right - A. I. Du Pont Estate, Junction of State Route 141 & Rockland Road, Wilmington, New Castle County, DE

227

8. Historic American Buildings Survey HABS Photocopy made from photograph ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Historic American Buildings Survey HABS Photocopy made from photograph from the Smithsonian Institution, Washington, D.C. DELAWARE LOG HOUSE EXHIBIT0 INSTALLED IN THE 'HALL OF EVERYDAY LIFE IN THE AMERICAN PAST,' MUSEUM OF HISTORY AND TECHNOLOGY, SMITHSONIAN INSTITUTION - Robinson-Murray House, Limestone Road, Milltown, New Castle County, DE

228

View southeast, overview of building group: coal house (HABS No. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View southeast, overview of building group: coal house (HABS No. WV-267-B), large tree, Albert Thacker House (267-A), wash house (267-C), Eustace Chadwick House (268-A) (on lot to south), chicken house (267-D), and small tree (left to right in photograph) - 3249 Cyrus Road (House), Cyrus, Wayne County, WV

229

Circulation a key factor in Mediterranean algal growth  

NASA Astrophysics Data System (ADS)

The early appearance of nitrate in December appears to have been the driving force for favorable conditions for algal blooms in the Mediterranean, a new study indicates. To better understand the role of nutrients' availability to enable the growth of phytoplankton in temperate seas, D'Ortenzio et al. installed nitrate concentration sensors on two profiling floats in the northwestern Mediterranean basin in summer 2011. Each spring, the phytoplankton in this basin rapidly grow to form a bloom that blankets the surface and contributes to the transport of carbon from the atmosphere to the deep ocean. Scientists are still unsure exactly what produces the conditions for these blooms, but they know that the availability of nutrients, induced by large-scale circulation in the oceans, during the winter is a factor.

Orwig, Jessica

2014-12-01

230

The origin of the Ulva macroalgal blooms in the Yellow Sea in 2013.  

PubMed

Green algal blooms have occurred in the Yellow Sea for seven consecutive years from 2007 to 2013. In this study, satellite image analysis and field shipboard observations indicated that the Ulva blooms in 2013 originated in the Rudong coast. The spatial distribution of Ulva microscopic propagules in the Southern Yellow Sea also supported that the blooms originated in the Rudong coast. In addition, multi-source satellite data were used to evaluate the biomass of green algae on the Pyropia aquaculture rafts. The results showed that approximately 2784 tons of Ulva prolifera were attached to the rafts and possessed the same internal transcribed spacer and 5S rDNA sequence as the dominant species in the 2013 blooms. We conclude that the significant biomass of Ulva species on the Pyropia rafts during the harvesting season in radial tidal sand ridges played an important role in the rapid development of blooms in the Yellow Sea. PMID:25444626

Zhang, Jianheng; Huo, Yuanzi; Wu, Hailong; Yu, Kefeng; Kim, Jang Kyun; Yarish, Charles; Qin, Yutao; Liu, Caicai; Xu, Ren; He, Peimin

2014-12-15

231

FATTY ACID AND STEROL COMPOSITION OF A KARENIA BREVIS BLOOM IN THE GULF OF MEXICO  

EPA Science Inventory

In the Gulf of Mexico, recurring algal blooms, caused by Karenia brevis (formerly known as Gymnodinium breve), have significant adverse health and economic impacts. K. brevis is one member of a small group of dinoflagellates, related morphologically and by DNA-based phylogenetic ...

232

Earth Return Aerocapture for the TransHab/Ellipsled Vehicle  

NASA Technical Reports Server (NTRS)

The current architecture being considered by NASA for a human Mars mission involves the use of an aerocapture procedure at Mars arrival and possibly upon Earth return. This technique would be used to decelerate the vehicles and insert them into their desired target orbits, thereby eliminating the need for propulsive orbital insertions. The crew may make the interplanetary journey in a large, inflatable habitat known as the TransHab. It has been proposed that upon Earth return, this habitat be captured into orbit for use on subsequent missions. In this case, the TransHab would be complimented with an aeroshell, which would protect it from heating during the atmospheric entry and provide the vehicle with aerodynamic lift. The aeroshell has been dubbed the "Ellipsled" because of its characteristic shape. This paper reports the results of a preliminary study of the aerocapture of the TransHab/Ellipsled vehicle upon Earth return. Undershoot and overshoot boundaries have been determined for a range of entry velocities, and the effects of variations in the atmospheric density profile, the vehicle deceleration limit, the maximum vehicle roll rate, the target orbit, and the vehicle ballistic coefficient have been examined. A simple, 180 degree roll maneuver was implemented in the undershoot trajectories to target the desired 407 km circular Earth orbit. A three-roll sequence was developed to target not only a specific orbital energy, but also a particular inclination, thereby decreasing propulsive inclination changes and post-aerocapture delta-V requirements. Results show that the TransHab/Ellipsled vehicle has a nominal corridor width of at least 0.7 degrees for entry speeds up to 14.0 km/s. Most trajectories were simulated using continuum flow aerodynamics, but the impact of high-altitude viscous effects was evaluated and found to be minimal. In addition, entry corridor comparisons have been made between the TransHab/Ellipsled and a modified Apollo capsule which is also being considered as the crew return vehicle; because of its slightly higher lift-to-drag ratio, the TransHab has a modest advantage with regard to corridor width. Stagnation-point heating rates and integrated heat loads were determined for a range of vehicle ballistic coefficients and entry velocities.

Muth, W. D.; Hoffmann, C.; Lyne, J. E.

2000-01-01

233

Possible importance of algal toxins in the Salton Sea, California  

USGS Publications Warehouse

In response to wildlife mortality including unexplained eared grebe (Podiceps nigricollis) die-off events in 1992 and 1994 and other mortality events including large fish kills, a survey was conducted for the presence of algal toxins in the Salton Sea. Goals of this survey were to determine if and when algal toxins are present in the Salton Sea and to describe the phytoplankton composition during those times. A total of 29 samples was collected for toxicity analysis from both nearshore and midlake sites visited biweekly from January to December 1999. Dinoflagellates and diatoms dominated most samples, but some were dominated by a prymnesiophyte (Pleurochrysis pseudoroscoffensis) or a raphidophyte (Chattonella marina). Several types of blooms were observed and sampled. The dinoflagellate Gyrodinium uncatenum formed an extensive, dense (up to 310 000 cells ml-1) and long-lasting bloom during the winter in 1999. A coccolithophorid, Pleurochrysis pseudoroscoffensis, occurred at high densities in surface films and nearshore areas during the spring and summer of 1999. These surface films also contained high densities of one or two other species (an unidentified scrippsielloid, Heterocapsa niei, Chattonella marina). Localized blooms were also observed in the Salton Sea. An unknown small dinoflagellate reached high densities (110 000 cells ml-1) inside Varner Harbor, and an unidentified species of Gymnodinium formed a dense (270 000 cells ml-1) band along part of the southern shoreline during the summer. Three species known to produce toxins in other systems were found. Protoceratium reticulatum (=Gonyaulax grindleyi) and Chattonella marina were found in several samples taken during summer months, and Prorocentrum minimum was found in low densities in several samples. Extracts of most samples, including those containing known toxic species, showed a low level (<10% mortality across all concentrations) of activity in the brine shrimp lethality assay and were not considered toxic. All sample extracts tested in the mouse bioassay showed no activity. One sample extract taken from the bloom of the small dinoflagellate was highly active (100% mortality across all concentrations) in the brine shrimp lethality assay, but the active material could not be isolated. While dense algal blooms are common at the Salton Sea, no evidence gathered in this study suggests that algal toxins are present within phytoplankton cells; however, toxins actively excreted by cells may have been missed. Blooms of phytoplankton likely contribute to wildlife mortality at the Salton Sea. Possible mechanisms including intoxication due to ingestion of feathers in grebes and waterlogging caused by changes in surface tension are discussed.

Reifel, K.M.; McCoy, M.P.; Rocke, T.E.; Tiffany, M.A.; Hurlbert, S.H.; Faulkner, D.J.

2002-01-01

234

Photolysis of iron–siderophore chelates promotes bacterial–algal mutualism  

PubMed Central

Marine microalgae support world fisheries production and influence climate through various mechanisms. They are also responsible for harmful blooms that adversely impact coastal ecosystems and economies. Optimal growth and survival of many bloom-forming microalgae, including climatically important dinoflagellates and coccolithophores, requires the close association of specific bacterial species, but the reasons for these associations are unknown. Here, we report that several clades of Marinobacter ubiquitously found in close association with dinoflagellates and coccolithophores produce an unusual lower-affinity dicitrate siderophore, vibrioferrin (VF). Fe-VF chelates undergo photolysis at rates that are 10–20 times higher than siderophores produced by free-living marine bacteria, and unlike the latter, the VF photoproduct has no measurable affinity for iron. While both an algal-associated bacterium and a representative dinoflagellate partner, Scrippsiella trochoidea, used iron from Fe-VF chelates in the dark, in situ photolysis of the chelates in the presence of attenuated sunlight increased bacterial iron uptake by 70% and algal uptake by >20-fold. These results suggest that the bacteria promote algal assimilation of iron by facilitating photochemical redox cycling of this critical nutrient. Also, binary culture experiments and genomic evidence suggest that the algal cells release organic molecules that are used by the bacteria for growth. Such mutualistic sharing of iron and fixed carbon has important implications toward our understanding of the close beneficial interactions between marine bacteria and phytoplankton, and the effect of these interactions on algal blooms and climate. PMID:19805106

Amin, Shady A.; Green, David H.; Hart, Mark C.; Küpper, Frithjof C.; Sunda, William G.; Carrano, Carl J.

2009-01-01

235

Algal conditions in the Caloosahatchee River (1975-79), Lake Okeechobee to Franklin Lock, Florida  

USGS Publications Warehouse

Maximum numbers of suspended algae occurred in late spring and early summer, in each of the years 1975-79, in the Caloosahatchee River. Numbers exceeded 100,000 cells per milliliter at all stations sometime during the study. Concentrations decreased during late summer and autumn and were low during winter, except in January 1979 when numbers at most sites exceeded 100,000 cells per milliliter. The January 1979 bloom coincided with large discharges from Lake Okeechobee. During previous winters, discharges and algal numbers were lower. During other seasons, algal blooms occurred most frequently under low-flow or stagnant conditions. The upstream site at Moore Haven, which had the least discharge and was most stagnant, had consistently higher algal concentrations than downstream sites. Blue-green algae were dominant in the river during the summer at the upstream site throughout the year. The percentage of blue-green algae decreased downstream. Concentrations of nitrite plus nitrate nitrogen were inversely correlated with concentrations of algae and decreased to near zero during algal blooms. The low concentrations of these forms of inorganic nitrogen relative to other major nutrients probably favor blue-green algae and limit growth of other algae. Contributions by the basin tributaries to the nutritive condition of the river were small because concentrations of nutrients, algal growth potential, and algae in the tributaries were generally less than those in the river. (USGS)

McPherson, Benjamin F.; La Rose, Henry R.

1982-01-01

236

Bering Sea in Bloom  

NASA Technical Reports Server (NTRS)

The surface waters of the Bering Sea around the Pribilof Islands, off Alaska's west coast, exhibited a dark green color on May 15, 2002, in this SeaWiFS true-color image. The green color of the currents there suggests the presence of a large phytoplankton bloom. Careful inspection reveals some a reddish tinges of light reflected by this bloom, particularly in a long east to west band just south of the Pribilof Islands, and just north of the Aleutian Island chain (disappearing toward the lower righthand corner of this scene beneath the cloud bank). Some scientists speculate this could be another Phaeocystis bloom, similar to the bloom of this species that was observed in these waters roughly this time last year. Such blooms are typically accompanied by a strong, unpleasant odor in the immediate vicinity. The light brown color of the surface waters along the Alaskan shoreline are probably due to suspended sediments washed off from the land. Image courtesy the SeaWiFS Project, NASA GSFC, and ORBIMAGE

2002-01-01

237

TransHab: NASA's Large-Scale Inflatable Spacecraft  

NASA Technical Reports Server (NTRS)

TransHab is a, 27-foot diameter by 40-foot, lightweight inflatable habitation module for space applications. TransHab consists of a lightweight graphite-composite core, 11-foot diameter by 23-foot tall, surrounded by a 27-foot diameter inflatable shell. Originally envisioned to be the habitation module of an interplanetary transit vehicle, TransHab is currently being considered as a module for use on the International Space Station (ISS). During the past two years, several tests have been performed at the NASA/Johnson Space Center to demonstrate and prove the technologies required in building a large-scale inflatable habitation module. This paper discusses the results of these tests which including the following: 1) a structural integrity development test article hydJ"Ostatically tested to four times ambient pressure, 2) a full-scale development test article manufactured, assembled, folded and deployed at vacuum, and 3) extensive hypervelocity impact testing of the micro meteoroid and orbital debris protection system.

delaFuente, Horacio; Raboin, Jasen L.; Spexarth, Gary R.; Valle, Gerard D.

2000-01-01

238

Response of copepod grazing and reproduction to different taxa of spring bloom phytoplankton in the Southern Yellow Sea  

NASA Astrophysics Data System (ADS)

The responses of copepod grazing and reproduction to the spring phytoplankton bloom were studied in the temperate shelf water of the Southern Yellow Sea in March-April, 2009. Two different algal blooms were found during the cruises. A diatom-dominated bloom at Station Z11, and a dinoflagellate-dominated bloom at Station Z4. The gut pigment contents indicated that different sized copepods exhibited different responses to different-species phytoplankton blooms. Large copepods (LC: body size larger than 1000 ?m) and medium copepods (MC: body size ranging from 500 to 1000 ?m), grazed actively on diatom blooms, but inactively on dinoflagellate blooms, although the chlorophyll-a concentrations of dinoflagellate blooms were twice as high as than those of the diatom blooms. For small copepods (SC: body size smaller than 500 ?m), however, there was no significant difference in gut pigment contents between the two different algal blooms. Among the three size groups, LCs were the major grazers on the diatom bloom, while SCs were major grazers on the dinoflagellate bloom. Grazing impacts of copepod assemblages on phytoplankton blooms were low, only being equivalent to 1% day-1, or less, of the chlorophyll-a standing stock. The egg production rates of a large copepod, Calanus sinicus, were on average, 11.3 egg ind.-1 day-1, which was among the higher levels recorded in the study area, especially at the two stations where phytoplankton was blooming (21.8 and 14.9 egg ind.-1 day-1 at Stations Z11 and Z4, respectively). However, C. sinicus could only obtain sufficient food to support this high reproduction from the diatom bloom, but could not if relying only on the apparently unpalatable dinoflagellate bloom. Our analysis of copepod grazing and reproduction suggests that, although the spring blooms do enhance the reproduction of copepods, the taxa changed during spring blooms from large diatoms to small dinoflagellates would change the pathway of primary production. This would restructure secondary-producers (e.g. copepods) community structure, and have important ramifications through various marine trophic levels in the Southern Yellow Sea.

Li, Chaolun; Yang, Guang; Ning, Juan; Sun, Jun; Yang, Bo; Sun, Song

2013-12-01

239

Enumeration of bacteria from a Trichodesmium spp. bloom of the Eastern Arabian Sea: elucidation of their possible role in biogeochemistry  

Microsoft Academic Search

The carbon-flux via algal bloom events involves bacteria as an important mediator. The present study, carried out during the\\u000a spring inter-monsoon month of April 2008 onboard CRV Sagar Manjusha-06 in the Eastern Arabian Sea, addresses the bloom-specific\\u000a flow of carbon to bacteria via chromophoric dissolved organic matter (CDOM). Eleven stations monitored were located in the\\u000a coastal, shelf and open-ocean areas

Subhajit Basu; S. G. Prabhu Matondkar; Irene Furtado

2011-01-01

240

Continuous Blooming of Convex Polyhedra  

E-print Network

We construct the first two continuous bloomings of all convex polyhedra. First, the source unfolding can be continuously bloomed. Second, any unfolding of a convex polyhedron can be refined (further cut, by a linear number ...

Demaine, Erik D.

241

NESDIS Center for Satellite Applications and Research Highlights: Science Research & Applications in calendar Year 2005  

E-print Network

the relative abundance of Karlodinium micrum, a harmful algal bloom (HAB) species,in Chesapeake Bay (Fig. 1 of the relative abundance of the ichthyotoxic dinoflagellate Karlodinium micrum in Chesapeake Bay on April 20

Kuligowski, Bob

242

DETOXIFICATION OF CYANOBACTERIAL TOXIN - CONTAMINATED WATER USING TIO2 PHOTOCATALYTIC FILMS  

EPA Science Inventory

Cyanobacterial harmfal algal blooms (CyanoHABs) often produce undesirable color, odor and taste and more importantly, potent toxins that can cause chronic, acute and acute letha poisonings to wild and domestic animals and humans...

243

Predicting potentially toxigenic Pseudo-nitzschia blooms in the Chesapeake Bay  

USGS Publications Warehouse

Harmful algal blooms are now recognized as a significant threat to the Chesapeake Bay as they can severely compromise the economic viability of important recreational and commercial fisheries in the largest estuary of the United States. This study describes the development of empirical models for the potentially domoic acid-producing Pseudo-nitzschia species complex present in the Bay, developed from a 22-year time series of cell abundance and concurrent measurements of hydrographic and chemical properties. Using a logistic Generalized Linear Model (GLM) approach, model parameters and performance were compared over a range of Pseudo-nitzschia bloom thresholds relevant to toxin production by different species. Small-threshold blooms (???10cellsmL-1) are explained by time of year, location, and variability in surface values of phosphate, temperature, nitrate plus nitrite, and freshwater discharge. Medium- (100cellsmL-1) to large- threshold (1000cellsmL-1) blooms are further explained by salinity, silicic acid, dissolved organic carbon, and light attenuation (Secchi) depth. These predictors are similar to other models for Pseudo-nitzschia blooms on the west coast, suggesting commonalities across ecosystems. Hindcasts of bloom probabilities at a 19% bloom prediction point yield a Heidke Skill Score of -53%, a Probability of Detection ~75%, a False Alarm Ratio of ~52%, and a Probability of False Detection ~9%. The implication of possible future changes in Baywide nutrient stoichiometry on Pseudo-nitzschia blooms is discussed. ?? 2010 Elsevier B.V.

Anderson, C.R.; Sapiano, M.R.P.; Prasad, M.B.K.; Long, W.; Tango, P.J.; Brown, C.W.; Murtugudde, R.

2010-01-01

244

The decline process and major pathways of Microcystis bloom in Taihu Lake, China  

NASA Astrophysics Data System (ADS)

Eutrophication has become a serious concern in many lakes, resulting in cyanobacterial blooms. However, the mechanism and pathways of cyanobacteria decline are less understood. To identify and define the growth and decline of Microcystis blooms in Taihu Lake of China, and to illuminate the destination of surface floating blooms, we investigated the biomass distribution and variations in colony size, morphology, and floating velocity from October 2008 to September 2009. The results showed that the Microcystis bloom declined in response to biomass decrease, colony disaggregation, buoyancy reduction, and increased phytoplankton biodiversity, and these indicative parameters could be applied for recognition of the development phases of the bloom. Three major decline pathways were proposed to describe the bloom decline process, colony disaggregation (Pathway I), colony settlement (Pathway II), and cell lysis in colonies (Pathway III). We proposed a strategy to define the occurrence and decline of Microcystis blooms, to evaluate the survival state under different stress conditions, and to indicate the efficiency of controlling countermeasures against algal blooms.

Wang, Zhicong; Li, Guowen; Li, Genbao; Li, Dunhai

2012-01-01

245

A new approach to discriminate dinoflagellate from diatom blooms from space in the East China Sea  

NASA Astrophysics Data System (ADS)

and diatom blooms often occur in the East China Sea (ECS) during spring and summer. Some of the dinoflagellate blooms are toxic, resulting in widespread economic damage. In order to mitigate the negative impacts, remote-sensing methods that can effectively and accurately discriminate between bloom types are demanded for early warning and continuous monitoring of bloom events at large scales. An in situ bio-optical data set collected from diatom and dinoflagellate blooming waters indicates that the two types of blooms exhibited distinctive differences in the shapes and magnitudes of remote-sensing reflectance (Rrs). The ratio of in situ measured Rrs spectral slopes at two spectral ranges (443-488 and 531-555 nm, bands available with the moderate resolution imaging spectrometer (MODIS) sensor), abbreviated as BI (representing bloom index), was found effective in differentiating dinoflagellates from diatoms. Reflectance model simulations, which were carried out using in situ and algal culture data as input, provided consistent results. A classification approach for separating dinoflagellate from diatom blooms in the ECS was then developed: When fluorescence line height (FLH) is doubled over the background level and total absorption coefficient at 443 nm ? 0.5 m-1, if 0.0 < BI ? 0.3, it suggests a dinoflagellate bloom; if 0.3 < BI ? 1.0, it suggests a diatom bloom. Finally, the approach was applied to MODIS measurements over the ECS, and a series of diatom and dinoflagellate bloom events during April-June 2005 and 2011 were successfully identified, suggesting that the proposed approach is generally valid for the ECS.

Shang, Shaoling; Wu, Jingyu; Huang, Bangqin; Lin, Gong; Lee, Zhongping; Liu, James; Shang, Shaoping

2014-07-01

246

National Algal Biofuels Technology Roadmap  

E-print Network

National Algal Biofuels Technology Roadmap MAY 2010 BIOMASS PROGRAM #12;#12;U.S. DOE 2010. National Algal Biofuels Technology Roadmap. U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Biomass Program. Visit http://biomass.energy.gov for more information National Algal Biofuels

247

New Neutrinos Algal Biofuels  

E-print Network

New Neutrinos Algal Biofuels Charged-Particle Vision Primordial Soup LOS ALAMOS SCIENCE in Illinois, a beam of neutrino particles streams through the MiniBooNE detector. This experiment tests the degree to which neutrinos shift from one "flavor" to another. Each neutrino normally travels as a mixture

248

A Taste of Algal Genomes from the Joint Genome Institute  

SciTech Connect

Algae play profound roles in aquatic food chains and the carbon cycle, can impose health and economic costs through toxic blooms, provide models for the study of symbiosis, photosynthesis, and eukaryotic evolution, and are candidate sources for bio-fuels; all of these research areas are part of the mission of DOE's Joint Genome Institute (JGI). To date JGI has sequenced, assembled, annotated, and released to the public the genomes of 18 species and strains of algae, sampling almost all of the major clades of photosynthetic eukaryotes. With more algal genomes currently undergoing analysis, JGI continues its commitment to driving forward basic and applied algal science. Among these ongoing projects are the pan-genome of the dominant coccolithophore Emiliania huxleyi, the interrelationships between the 4 genomes in the nucleomorph-containing Bigelowiella natans and Guillardia theta, and the search for symbiosis genes of lichens.

Kuo, Alan; Grigoriev, Igor

2012-06-17

249

A Collection of Algal Genomes from the JGI  

SciTech Connect

Algae, defined as photosynthetic eukaryotes other than plants, constitute a major component of fundamental eukaryotic diversity. Acquisition of the ability to conduct oxygenic photosynthesis through endosymbiotic events has been a principal driver of eukaryotic evolution, and today algae continue to underpin aquatic food chains as primary producers. Algae play profound roles in the carbon cycle, can impose health and economic costs through toxic blooms, and are candidate sources for bio-fuels; all of these research areas are part of the mission of DOE?s Joint Genome Institute (JGI). A collection of algal projects ongoing at JGI contributes to each of these areas and illustrates analyses employed in their genome exploration.

Kuo, Alan; Grigoriev, Igor

2012-03-19

250

Lab 7: Nitrates and Phosphates and Algae, Oh My!  

NSDL National Science Digital Library

Human-induced nutrient loading of the world's oceans has been linked to increased and prolonged algae blooms, sometimes with potentially deadly consequences. In this investigation, students will create their own algal blooms, analyze satellite images of chlorophyll concentrations in the Sea of CortÃs, and learn about two alarming consequences of excessive algae growth-?dead zones and harmful algae blooms (HABs).

251

[Advance in study on the effects of iron on algal growth and spectral recognition].  

PubMed

Iron is an essential micronutrient of phytoplankton. Iron plays an important role in many biological processes such as nitrogen assimilation, N2 fixation, photosynthetic and respiratory electron transport, and porphyrin biosynthesis. Therefore, the regulation effects of iron should be considered besides nitrogen and phosphorus during the treatment of eutrophication lakes process. Remote sensing technology has been recognized as an effective measure in monitoring eutrophicated water bodies which could be used to timely monitor the distribution and growth status of algal on a large scale. The iron concentration fluctuation may have an important influence on the metabolic activity of the algal cells, and the spectral reflectivity could reflect the physiological characteristics of algal. The relationship between land features and their spectral characteristics is important for the interpretation of remote sensing images. Studies of algal spectral propertises under different iron-supply would be meaningful for determining the bloom and developing the remote sensing warning system of lake eutrophication. In the present paper, the effects of iron on the growth of algal and the advances in studies of algal spectrum are summarized based on the iron hypothesis. Furthermore, the application of spectral properties of algal under different iron-supply in early-warning mechanism of lake eutrophication is prospected. PMID:20210166

Chi, Guang-Yu; Chen, Xin; Shi, Yi; Zheng, Tai-Hui

2009-12-01

252

Effect of Oxidative Stress Induced by Brevibacterium sp. BS01 on a HAB Causing Species-Alexandrium tamarense  

PubMed Central

Harmful algal blooms occur all over the world, destroying aquatic ecosystems and threatening other organisms. The culture supernatant of the marine algicidal actinomycete BS01 was able to lysis dino?agellate Alexandrium tamarense ATGD98-006. Physiological and biochemical responses to oxidative stress in A. tamarense were investigated to elucidate the mechanism involved in BS01 inhibition of algal growth. Transmission electron microscope analysis revealed that there were some chloroplast abnormalities in response to BS01 supernatant. The decrease in cellular-soluble protein content suggested that cell growth was greatly inhibited at high concentration of BS01 supernatant. The increase in the levels of reactive oxygen species (ROS) and malondialdehyde contents following exposure to BS01 supernatant indicated that algal cells suffered from oxidative damage. The content of pigment was significantly decreased after 12 h treatment, which indicated that the accumulation of ROS destroyed pigment synthesis. Moreover, the decrease of Fv/Fm ratio suggested that in the photosynthetic system, the dominant sites producing ROS were destroyed by the supernatant of the BS01 culture. The activities of the antioxidant enzymes including superoxide dismutase and peroxidase increased in a short time and decreased slightly with increasing exposure time. A real-time PCR assay showed changes in the transcript abundances of two photosynthetic genes, psbA and psbD. The results showed that BS01 supernatant reduced the expression of the psbA gene after 2 h exposure, but the expression of the psbD gene was increased at concentrations of 1.0 and 1.5%. Our results demonstrated that the expression of the psbA gene was inhibited by the BS01 supernatant, which might block the electron transport chain, significantly enhancing ROS level and excess activity of the antioxidant system. The accumulation of ROS destoryed pigment synthesis and membrane integrity, and inhibited or ultimately killed the algal cells. PMID:23667564

Zhou, Yanyan; Zhang, Bangzhou; Zhang, Su; Li, Dong; Chen, Zhangran; Li, Yi; Bai, Shijie; Lv, Jinglin; Zheng, Wei; Tian, Yun; Zheng, Tianling

2013-01-01

253

Phytoplankton Bloom Off Portugal  

NASA Technical Reports Server (NTRS)

Turquoise and greenish swirls marked the presence of a large phytoplankton bloom off the coast of Portugal on April 23, 2002. This true-color image was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. There are also several fires burning in northwest Spain, near the port city of A Coruna. Please note that the high-resolution scene provided here is 500 meters per pixel. For a copy of this scene at the sensor's fullest resolution, visit the MODIS Rapidfire site.

2002-01-01

254

North Atlantic Bloom  

NASA Technical Reports Server (NTRS)

Reminiscent of the distinctive swirls in a Van Gogh painting, millions of microscopic plants color the waters of the North Atlantic with strokes of blue, turquoise, green, and brown. Fed by nutrients that have built up during the winter and the long, sunlit days of late spring and early summer, the cool waters of the North Atlantic come alive every year with a vivid display of color. The microscopic plants, called phytoplankton, that give the water this color are the base of the marine food chain. Some species of phytoplankton are coated with scales of calcium (chalk), which turn the water electric blue. Chlorophyll and other light-capturing pigments in others give the water a deep green hue. The proliferation of many different species in various stages of growth and decay provides many nuances of color in this concentrated bloom. The bloom stretches across hundreds of kilometers, well beyond the edges of this photo-like image, captured on June 23, 2007, by the Moderate Resolution Imaging Spectroradiometer (MODIS) flying aboard NASA's Aqua satellite. The upper left edge of the image is bounded by Greenland. Iceland is in the upper right. Plumes of dust are blowing off the island, probably adding nutrients to the surface waters to its south. NASA image courtesy Norman Kuring, Ocean Color Group at NASA Goddard Space Flight Center

2007-01-01

255

Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data  

NASA Technical Reports Server (NTRS)

Visual and derivative analyses of AVIRIS spectral data can be used to detect algal accessory pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal accessory pigments for assessment of algal population composition. This research is based on the fact that many algal accessory pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of pigment signatures to construct pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The accessory pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such studies. We present here our results on detection of algal accessory pigments using AVIRIS data.

Richardson, Laurie L.; Ambrosia, Vincent G.

1996-01-01

256

Scales of temporal and spatial variability in the distribution of harmful algae species in the Indian River Lagoon, Florida, USA  

Microsoft Academic Search

This paper describes the results of a harmful algal bloom (HAB) monitoring effort in the Indian River Lagoon. The goal of the study was to describe spatial and temporal variability in the distribution, frequency of occurrence, and composition of HABs, along with an examination of potential driving factors, such as hydrologic conditions and nutrient concentrations. Six sampling sites in the

Edward J. Phlips; Susan Badylak; Mary Christman; Jennifer Wolny; Julie Brame; Jay Garland; Lauren Hall; Jane Hart; Jan Landsberg; Margaret Lasi; Jean Lockwood; Richard Paperno; Doug Scheidt; Ariane Staples; Karen Steidinger

2011-01-01

257

Associations between marine phytoplankton and symptoms of illness among recreational beachgoers in Puerto Rico, 2009  

EPA Science Inventory

While phytoplankton generally have crucial roles in marine ecosystems, a small subset can release toxins and produce harmful algal blooms (HABs). HABs can be a threat to human health as symptoms from exposure range from neurological impairment to gastrointestinal (GI), dermal, a...

258

The Need for Ocean Literacy in the Classroom: Part II  

ERIC Educational Resources Information Center

As mentioned in Part I, certain classroom activities can help students learn about the ocean and empower them to make informed decisions about their impacts on the environment. One such activity focuses on harmful algal blooms (HABs). In this article, the authors include background information on HABs and then present two activities. Activity 1 is…

Schoedinger, Sarah; Cava, Francesca; Jewell, Beth

2006-01-01

259

BIOTOXIN-INDUCED NEUROTOXICITY: AN EMERGING RISK FOR HUMAN HEALTH AND ECOLOGY.  

EPA Science Inventory

The increasing incidence of human illness associated with exposure to biotoxins from harmful algal blooms (HABs) in aquatic environments, and fungi and bacteria on land, may indicate an emerging human-health risk. HABs are reported to be increasing worldwide in frequency, duratio...

260

MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser  

E-print Network

harmful algal blooms (HABs) and red tides (Noctiluca spp.), as well as the role of jellyfish fish species. Jellyfish act as a buffer in eutrophicated and overfished systems, as they retain enrichment in promoting HAB species, Noctiluca and jellyfish. These fundamental con- straints, which

Chittka, Lars

261

Algal biofuels from wastewater treatment high rate algal ponds.  

PubMed

This paper examines the potential of algae biofuel production in conjunction with wastewater treatment. Current technology for algal wastewater treatment uses facultative ponds, however, these ponds have low productivity (?10 tonnes/ha.y), are not amenable to cultivating single algal species, require chemical flocculation or other expensive processes for algal harvest, and do not provide consistent nutrient removal. Shallow, paddlewheel-mixed high rate algal ponds (HRAPs) have much higher productivities (?30 tonnes/ha.y) and promote bioflocculation settling which may provide low-cost algal harvest. Moreover, HRAP algae are carbon-limited and daytime addition of CO(2) has, under suitable climatic conditions, the potential to double production (to ?60 tonnes/ha.y), improve bioflocculation algal harvest, and enhance wastewater nutrient removal. Algae biofuels (e.g. biogas, ethanol, biodiesel and crude bio-oil), could be produced from the algae harvested from wastewater HRAPs, The wastewater treatment function would cover the capital and operation costs of algal production, with biofuel and recovered nutrient fertilizer being by-products. Greenhouse gas abatement results from both the production of the biofuels and the savings in energy consumption compared to electromechanical treatment processes. However, to achieve these benefits, further research is required, particularly the large-scale demonstration of wastewater treatment HRAP algal production and harvest. PMID:21330711

Craggs, R J; Heubeck, S; Lundquist, T J; Benemann, J R

2011-01-01

262

Using a Multi-Component Indicator Toward Reducing Phytoplankton Bloom Occurrences in the Swan River Estuary  

NASA Astrophysics Data System (ADS)

The Swan River estuary is an icon of the city of Perth, Western Australia, running through the city centre and dividing the northern from the southern part of the city. However, frequent phytoplankton blooms have been observed in the estuary as a result of eutrophication. The Index of Sustainable Functionality (ISF), a composite index able to indicate for sustainable health of the estuary, was applied, taking into account the hydrology and highly seasonal nature of the estuary to inform the management of the estuary, towards the aim of reducing bloom occurrences. The study period was from the beginning of intensive monitoring in 1995 to mid-2009. The results emphasize the importance of physical controls on the ecology of the estuary. No significant trend in the estuary's low functionality was found, indicating that despite extensive restoration efforts, the frequency of algal bloom occurrences has remained relatively stationary and other mitigating factors have maintained an annual average ISF value at around 70 % functionality. We identified that the low flow season consistently performs the worst, with (high) temperature found as the most dominant variable for phytoplankton growth and bloom. Thus in managing the estuary, vigilance is required during periods of high temperature and low flow. Focusing on the risk of phytoplankton bloom, a nutrient reduction program that is in place is a long term solution due to high concentrations in the estuary. Other management measures need to be considered and adopted to effectively reduce the occurrences of future phytoplankton blooms.

Kristiana, Ria; Antenucci, Jason P.; Imberger, Jorg

2012-08-01

263

Assessment of microcystis bloom toxicity associated with wildlife mortality in the Kruger National Park, South Africa.  

PubMed

Based on previous necropsy results, Microcystis blooms in constructed water impoundments in the Kruger National Park (KNP) have been identified as a cause of wildlife mortality. In response to wildlife mortality during 2007, water samples, containing algal bloom material, were collected during February 2007 and July 2007 from four dams (Nhlanganzwani, Mpanamana, Makhohlola, and Sunset) in the southeastern part of the KNP as part of the follow-up investigation. The toxicity of the Microcystis blooms was determined using the enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition (PPI) assay, mouse bioassay, and African sharptooth catfish (Clarias gariepinus) primary hepatocytes. Both the ELISA and PPI assays indicated that the water sample collected during February 2007 from the Nhlanganzwani Dam, and samples collected from the Nhlanganzwani and Sunset dams in June 2007, were toxic. These dams, exhibiting the toxic Microcystis blooms, were also associated with the wildlife mortality. Mice injected intraperitoneally with water samples from Nhlanganzwani Dam (February 2007) induced hepatotoxicity and mortality within 1 hr. Primary hepatocytes from the sharptooth catfish exposed to samples from these dams gave similar results. This laboratory investigation and results strongly incriminate the toxic Microcystis blooms as the cause of the wildlife mortality. Eutrophication and bloom formation appear to have been the consequence of the high numbers of hippopotami (Hippopotamus amphibius) in specific dams. PMID:20090022

Masango, Mxolisi G; Myburgh, Jan G; Labuschagne, Leonie; Govender, Danny; Bengis, Roy G; Naicker, Dharmarai

2010-01-01

264

An algal carbon budget for pelagic-benthic coupling in Lake Michigan  

USGS Publications Warehouse

Assimilation and respiration rates of Diporeia sp., an abundant benthic amphipod, and of sediment microheterotrophs were measured in a microcosm study. Release of radioisotope in the form of dissolved organic compounds was much lower than that incorporated and respired for both Diporeia and sediment bacteria. Of the 61 mmol C m-2 of algal C estimated to be deposited during the spring bloom. -from Authors

Fitzgerald, S.A.; Gardner, W.S.

1993-01-01

265

OSU Team Assembles X-Hab Loft - Duration: 0:32.  

NASA Video Gallery

This time lapse video shows the Oklahoma State University team in the process of assembling and inflating the loft they've built for the first X-Hab Academic Innovation Challenge. OSU is one of thr...

266

HABS DC,WASH,515A (sheet 1 of 4) Captain Henry Saunders ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HABS DC,WASH,515A- (sheet 1 of 4) - Captain Henry Saunders House, Virginia Room, National Museum of American History, Smithsonian Institution (moved from VA, Windsor vicinity, U.S. Route 460), Washington, District of Columbia, DC

267

Unveiling the transcriptional features associated with coccolithovirus infection of natural Emiliania huxleyi blooms.  

PubMed

Lytic viruses have been implicated in the massive cellular lysis observed during algal blooms, through which they assume a prominent role in oceanic carbon and nutrient flows. Despite their impact on biogeochemical cycling, the transcriptional dynamics of these important oceanic events is still poorly understood. Here, we employ an oligonucleotide microarray to monitor host (Emiliania huxleyi) and virus (coccolithovirus) transcriptomic features during the course of E. huxleyi blooms induced in seawater-based mesocosm enclosures. Host bloom development and subsequent coccolithovirus infection was associated with a major shift in transcriptional profile. In addition to the expected metabolic requirements typically associated with viral infection (amino acid and nucleotide metabolism, as well as transcription- and replication-associated functions), the results strongly suggest that the manipulation of lipid metabolism plays a fundamental role during host-virus interaction. The results herein reveal the scale, so far massively underestimated, of the transcriptional domination that occurs during coccolithovirus infection in the natural environment. PMID:22066669

Pagarete, António; Le Corguillé, Gildas; Tiwari, Bela; Ogata, Hiroyuki; de Vargas, Colomban; Wilson, William H; Allen, Michael J

2011-12-01

268

Bloom of Gymnodinium catenatum in Bahía Santiago and Bahía Manzanillo, Colima, Mexico.  

PubMed

Gymnodinium bloom events are of concern, since they produce toxins, which have unfavorable consequences to marine ecosystems, human health and the economy. This report describes the physico-chemical conditions that were present during the algal bloom event on May 2010 in Bahía Manzanillo and Bahía Santiago, Colima, Mexico. For this, seawater nutrient analysis, phytoplankton counts, identification, and toxicity tests were undertaken. Nutrients in seawater were determined using colorimetric techniques, the higher concentrations (8.88 microM DIN, 0.78 microM PO4 and 24.34 microM SiO2) were related with upwelling waters that promoted the algal bloom that began after registering the year lowest sea-surface temperature, favoring the rapid growth of G. catenatum (up to 1.02 x 10(7) cells/L). Phytoplankton counting was carried out using sedimentation chambers and cells enumerated on appropriated area. The bloom persisted in the bays for approximately two weeks and was associated with toxicity (determined with HPLC) in local oysters (1525.8 microg STXeq/100g), and in phytoplankton (10.9 pg STXeq/cells) samples. Strong variations in cell toxicity (1.4 to 10.9pg STXeq/cells), most likely reflected the availability of inorganic nutrients. The toxin profile of the phytoplankton samples consisted of 11 toxins and resembled those recorded for several strains of G. catenatum isolated from other coastal areas of Mexico. PMID:22458217

Quijano-Scheggia, Sonia; Olivos-Ortiz, Aramis; Bustillos-Guzmán, José J; Garcés, Esther; Gaviño-Rodríguez, Juan H; Galicia-Pérez, Marco A; Patiño-Barragan, Manuel; Band-Schmidt, Christine J; Hernández-Sandoval, Francisco J; López-Cortés, David J

2012-03-01

269

Decadal-Scale Changes of Dinoflagellates and Diatoms in the Anomalous Baltic Sea Spring Bloom  

PubMed Central

The algal spring bloom in the Baltic Sea represents an anomaly from the winter-spring bloom patterns worldwide in terms of frequent and recurring dominance of dinoflagellates over diatoms. Analysis of approximately 3500 spring bloom samples from the Baltic Sea monitoring programs revealed (i) that within the major basins the proportion of dinoflagellates varied from 0.1 (Kattegat) to >0.8 (central Baltic Proper), and (ii) substantial shifts (e.g. from 0.2 to 0.6 in the Gulf of Finland) in the dinoflagellate proportion over four decades. During a recent decade (1995–2004) the proportion of dinoflagellates increased relative to diatoms mostly in the northernmost basins (Gulf of Bothnia, from 0.1 to 0.4) and in the Gulf of Finland, (0.4 to 0.6) which are typically ice-covered areas. We hypothesize that in coastal areas a specific sequence of seasonal events, involving wintertime mixing and resuspension of benthic cysts, followed by proliferation in stratified thin layers under melting ice, favors successful seeding and accumulation of dense dinoflagellate populations over diatoms. This head-start of dinoflagellates by the onset of the spring bloom is decisive for successful competition with the faster growing diatoms. Massive cyst formation and spreading of cyst beds fuel the expanding and ever larger dinoflagellate blooms in the relatively shallow coastal waters. Shifts in the dominant spring bloom algal groups can have significant effects on major elemental fluxes and functioning of the Baltic Sea ecosystem, but also in the vast shelves and estuaries at high latitudes, where ice-associated cold-water dinoflagellates successfully compete with diatoms. PMID:21747911

Klais, Riina; Tamminen, Timo; Kremp, Anke; Spilling, Kristian; Olli, Kalle

2011-01-01

270

Decadal-scale changes of dinoflagellates and diatoms in the anomalous baltic sea spring bloom.  

PubMed

The algal spring bloom in the Baltic Sea represents an anomaly from the winter-spring bloom patterns worldwide in terms of frequent and recurring dominance of dinoflagellates over diatoms. Analysis of approximately 3500 spring bloom samples from the Baltic Sea monitoring programs revealed (i) that within the major basins the proportion of dinoflagellates varied from 0.1 (Kattegat) to >0.8 (central Baltic Proper), and (ii) substantial shifts (e.g. from 0.2 to 0.6 in the Gulf of Finland) in the dinoflagellate proportion over four decades. During a recent decade (1995-2004) the proportion of dinoflagellates increased relative to diatoms mostly in the northernmost basins (Gulf of Bothnia, from 0.1 to 0.4) and in the Gulf of Finland, (0.4 to 0.6) which are typically ice-covered areas. We hypothesize that in coastal areas a specific sequence of seasonal events, involving wintertime mixing and resuspension of benthic cysts, followed by proliferation in stratified thin layers under melting ice, favors successful seeding and accumulation of dense dinoflagellate populations over diatoms. This head-start of dinoflagellates by the onset of the spring bloom is decisive for successful competition with the faster growing diatoms. Massive cyst formation and spreading of cyst beds fuel the expanding and ever larger dinoflagellate blooms in the relatively shallow coastal waters. Shifts in the dominant spring bloom algal groups can have significant effects on major elemental fluxes and functioning of the Baltic Sea ecosystem, but also in the vast shelves and estuaries at high latitudes, where ice-associated cold-water dinoflagellates successfully compete with diatoms. PMID:21747911

Klais, Riina; Tamminen, Timo; Kremp, Anke; Spilling, Kristian; Olli, Kalle

2011-01-01

271

The Costs of Respiratory Illnesses Arising from Florida Gulf Coast Karenia brevis Blooms  

PubMed Central

Background Algal blooms of Karenia brevis, a harmful marine algae, occur almost annually off the west coast of Florida. At high concentrations, K. brevis blooms can cause harm through the release of potent toxins, known as brevetoxins, to the atmosphere. Epidemiologic studies suggest that aerosolized brevetoxins are linked to respiratory illnesses in humans. Objectives We hypothesized a relationship between K. brevis blooms and respiratory illness visits to hospital emergency departments (EDs) while controlling for environmental factors, disease, and tourism. We sought to use this relationship to estimate the costs of illness associated with aerosolized brevetoxins. Methods We developed a statistical exposure–response model to express hypotheses about the relationship between respiratory illnesses and bloom events. We estimated the model with data on ED visits, K. brevis cell densities, and measures of pollen, pollutants, respiratory disease, and intra-annual population changes. Results We found that lagged K. brevis cell counts, low air temperatures, influenza outbreaks, high pollen counts, and tourist visits helped explain the number of respiratory-specific ED diagnoses. The capitalized estimated marginal costs of illness for ED respiratory illnesses associated with K. brevis blooms in Sarasota County, Florida, alone ranged from $0.5 to $4 million, depending on bloom severity. Conclusions Blooms of K. brevis lead to significant economic impacts. The costs of illness of ED visits are a conservative estimate of the total economic impacts. It will become increasingly necessary to understand the scale of the economic losses associated with K. brevis blooms to make rational choices about appropriate mitigation. PMID:19672403

Hoagland, Porter; Jin, Di; Polansky, Lara Y.; Kirkpatrick, Barbara; Kirkpatrick, Gary; Fleming, Lora E.; Reich, Andrew; Watkins, Sharon M.; Ullmann, Steven G.; Backer, Lorraine C.

2009-01-01

272

Late Blooming or Language Problem?  

MedlinePLUS

Late Blooming or Language Problem? Parents are smart. They listen to their child talk and know how he or she communicates. They also ... or not their child is developing speech and language at a normal rate. If parents think that ...

273

Algal functional annotation tool  

SciTech Connect

The Algal Functional Annotation Tool is a web-based comprehensive analysis suite integrating annotation data from several pathway, ontology, and protein family databases. The current version provides annotation for the model alga Chlamydomonas reinhardtii, and in the future will include additional genomes. The site allows users to interpret large gene lists by identifying associated functional terms, and their enrichment. Additionally, expression data for several experimental conditions were compiled and analyzed to provide an expression-based enrichment search. A tool to search for functionally-related genes based on gene expression across these conditions is also provided. Other features include dynamic visualization of genes on KEGG pathway maps and batch gene identifier conversion.

Lopez, D. [UCLA; Casero, D. [UCLA; Cokus, S. J. [UCLA; Merchant, S. S. [UCLA; Pellegrini, M. [UCLA

2012-07-01

274

Black Sea in Bloom  

NASA Technical Reports Server (NTRS)

This true-color image shows bright, turquoise-colored swirls across the surface of the Black Sea, signifying the presence of a large phytoplankton bloom. Scientists have observed similar blooms recurring annually, roughly this same time of year. The Sea of Azov, which is the smaller body of water located just north of the Black Sea in this image, also shows a high level of biological activity currently ongoing. The brownish pixels in the Azov are probably sediments carried in from high waters upstream. This scene was acquired by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on May 4, 2002. According to the Black Sea Environment Programme's Marine Hydrophysical Institute, the Black Sea is 'one of the marine areas of the world most damaged by human activities.' The coastal zone around these Eastern European inland water bodies is densely populated-supporting a permanent population of roughly 16 million people and another 4 million tourists each year. Six countries border with the Black Sea, including Ukraine to the north, Russia and Georgia to the east, Turkey to the south, and Bulgaria and Romania to the west. Because it is isolated from the world's oceans, and because there is an extensive drainage network of rivers that empty into it, the Black Sea has a unique and delicate water balance which is very important for supporting its marine ecosystem. Of particular concern to scientists is the salinity, water level, and nutrient levels of the Black Sea's waters, all of which are, unfortunately, being impacted by human activities. Within the last three decades the combination of increased nutrient loads from human sources together with pollution and over-harvesting of fisheries has resulted in a sharp decline in water quality. Scientists from each of the Black Sea's bordering nations are currently working together to study the issues and formulate a joint, international strategy for saving this unique marine ecosystem. Working with a spirit of placing more emphasis on joint ownership of the Black Sea's resources, and less emphasis on blame, it is hoped that the cooperating countries can strike an effective balance between both enjoying and preserving the Black Sea. Image courtesy the SeaWiFS Project, NASA GSFC, and ORBIMAGE

2002-01-01

275

Modelling the production of dimethylsulfide during a phytoplankton bloom  

NASA Astrophysics Data System (ADS)

Dimethylsulfide (DMS) is an important sulfur-containing atmospheric trace gas of marine biogenic origin. DMS emitted from the oceans may be a precursor of tropospheric aerosols and cloud condensation nuclei (CCN), thereby affecting the Earth's radiative balance and possibly constituting a negative feedback to global warming, although this hypothesis is still somewhat controversial. The revised conceptual model of the marine pelagic food web gives a central role to planktonic bacteria. Recent experiments have shown that consumption of dissolved DMS by microbial metabolism may be more important than atmospheric exchange in controlling its concentration in surface waters and hence its ventilation to the atmosphere. In this paper we investigate the effect of the marine food web on cycling of dissolved DMS in surface waters during a phytoplankton bloom episode. A nitrogen-based flow network simulation model has been used to analyze the relative importance of the various biological and chemical processes involved. The model predictions suggest that the concentration of DMS in marine surface waters is indeed governed by bacterial metabolism. Environmental factors that affect the bacterial compartment are thus likely to have a relatively large influence on dissolved DMS concentrations. The ecological succession is particularly sensitive to the ratio of phytoplankton to bacterial nutrient uptake rates as well the interaction between herbivore food chain and the microbial loop. Importantly for the design of field studies, the model predicts that peak DMS concentrations are achieved during the decline of the phytoplankton bloom with a typical time lag between peak DMS and peak phytoplankton biomass of 1 to 2 days. Significantly, the model predicts a relatively high DMS concentration persisting after the phytoplankton bloom due to excretion from large protozoa and zooplankton, which may be an additional explanation for the lack of correlation between DMS and chlorophyll a field measurements. Comparison of the model predictions has been made with tank algal bloom experiments.

Gabric, Albert; Murray, Nicholas; Stone, Lewi; Kohl, Manfred

1993-12-01

276

Alexandrium fundyense cysts in the Gulf of Maine: long-term time series of abundance and distribution, and linkages to past and future blooms  

USGS Publications Warehouse

Here we document Alexandrium fundyense cyst abundance and distribution patterns over nine years (1997 and 2004–2011) in the coastal waters of the Gulf of Maine (GOM) and identify linkages between those patterns and several metrics of the severity or magnitude of blooms occurring before and after each autumn cyst survey. We also explore the relative utility of two measures of cyst abundance and demonstrate that GOM cyst counts can be normalized to sediment volume, revealing meaningful patterns equivalent to those determined with dry weight normalization. Cyst concentrations were highly variable spatially. Two distinct seedbeds (defined here as accumulation zones with>300 cysts cm?3) are evident, one in the Bay of Fundy (BOF) and one in mid-coast Maine. Overall, seedbed locations remained relatively constant through time, but their area varied 3–4 fold, and total cyst abundance more than 10 fold among years. A major expansion of the mid-coast Maine seedbed occurred in 2009 following an unusually intense A. fundyense bloom with visible red-water conditions, but that feature disappeared by late 2010. The regional system thus has only two seedbeds with the bathymetry, sediment characteristics, currents, biology, and environmental conditions necessary to persist for decades or longer. Strong positive correlations were confirmed between the abundance of cysts in both the 0–1 and the 0–3 cm layers of sediments in autumn and geographic measures of the extent of the bloom that occurred the next year (i.e., cysts?blooms), such as the length of coastline closed due to shellfish toxicity or the southernmost latitude of shellfish closures. In general, these metrics of bloom geographic extent did not correlate with the number of cysts in sediments following the blooms (blooms?cysts). There are, however, significant positive correlations between 0–3 cm cyst abundances and metrics of the preceding bloom that are indicative of bloom intensity or vegetative cell abundance (e.g., cumulative shellfish toxicity, duration of detectable toxicity in shellfish, and bloom termination date). These data suggest that it may be possible to use cyst abundance to empirically forecast the geographic extent of the forthcoming bloom and, conversely, to use other metrics from bloom and toxicity events to forecast the size of the subsequent cyst population as the inoculum for the next year's bloom. This is an important step towards understanding the excystment/encystment cycle in A. fundyense bloom dynamics while also augmenting our predictive capability for this HAB-forming species in the GOM.

Anderson, Donald M.; Keafer, Bruce A.; Kleindinst, Judith L.; McGillicuddy, Dennis J., Jr.; Martin, Jennifer L.; Norton, Kerry; Pilskaln, Cynthia H.; Smith, Juliette L.; Sherwood, Christopher R.; Butman, Bradford

2014-01-01

277

Alexandrium fundyense cysts in the Gulf of Maine: Long-term time series of abundance and distribution, and linkages to past and future blooms  

NASA Astrophysics Data System (ADS)

Here we document Alexandrium fundyense cyst abundance and distribution patterns over nine years (1997 and 2004-2011) in the coastal waters of the Gulf of Maine (GOM) and identify linkages between those patterns and several metrics of the severity or magnitude of blooms occurring before and after each autumn cyst survey. We also explore the relative utility of two measures of cyst abundance and demonstrate that GOM cyst counts can be normalized to sediment volume, revealing meaningful patterns equivalent to those determined with dry weight normalization. Cyst concentrations were highly variable spatially. Two distinct seedbeds (defined here as accumulation zones with>300 cysts cm-3) are evident, one in the Bay of Fundy (BOF) and one in mid-coast Maine. Overall, seedbed locations remained relatively constant through time, but their area varied 3-4 fold, and total cyst abundance more than 10 fold among years. A major expansion of the mid-coast Maine seedbed occurred in 2009 following an unusually intense A. fundyense bloom with visible red-water conditions, but that feature disappeared by late 2010. The regional system thus has only two seedbeds with the bathymetry, sediment characteristics, currents, biology, and environmental conditions necessary to persist for decades or longer. Strong positive correlations were confirmed between the abundance of cysts in both the 0-1 and the 0-3 cm layers of sediments in autumn and geographic measures of the extent of the bloom that occurred the next year (i.e., cysts?blooms), such as the length of coastline closed due to shellfish toxicity or the southernmost latitude of shellfish closures. In general, these metrics of bloom geographic extent did not correlate with the number of cysts in sediments following the blooms (blooms?cysts). There are, however, significant positive correlations between 0-3 cm cyst abundances and metrics of the preceding bloom that are indicative of bloom intensity or vegetative cell abundance (e.g., cumulative shellfish toxicity, duration of detectable toxicity in shellfish, and bloom termination date). These data suggest that it may be possible to use cyst abundance to empirically forecast the geographic extent of the forthcoming bloom and, conversely, to use other metrics from bloom and toxicity events to forecast the size of the subsequent cyst population as the inoculum for the next year's bloom. This is an important step towards understanding the excystment/encystment cycle in A. fundyense bloom dynamics while also augmenting our predictive capability for this HAB-forming species in the GOM.

Anderson, Donald M.; Keafer, Bruce A.; Kleindinst, Judith L.; McGillicuddy, Dennis J.; Martin, Jennifer L.; Norton, Kerry; Pilskaln, Cynthia H.; Smith, Juliette L.; Sherwood, Christopher R.; Butman, Bradford

2014-05-01

278

Closed Environment Module - modularization and extension of the V-HAB  

NASA Astrophysics Data System (ADS)

The `Virtual Habitat' (V-HAB), is a Life Support System (LSS) simulation, created to provide the possibility for dynamic simulation of LSS for future human spaceflight missions. V-HAB creates the option to optimize LSS during early design phases. Furthermore, it allows simulating e.g. worst case scenarios which cannot be tested in reality. In a nutshell the tool allows the testing of LSS robustness by means of computer simulations. V-HAB is a modular simulation consisting of a: Closed Environment Module (CEM) Crew Module Biological Module Physio-Chemical Module The focus of the paper will be the Closed Environment Module (CEM) which is the core of V-HAB. The main function of the CEM is the embedding of all modules in the entire simulation and the control of the LSS. The CEM includes the possibility to simulate an arbitrary number of compartments and tanks with the interaction between connected compartments. Furthermore, a control program to actuate the LSS Technologies was implemented in the CEM, and is also introduced. In this paper the capabilities of the CEM are introduced based on selected test cases. In particular the following capabilities are demonstrated: Supply Leakage ON/OFF controller Power management Un-/docking Controller for tanks with maximum filling degree The CEM of the V-HAB simulation was verified by simulating the Atmosphere Revitalization part of the ISS and comparing it to actual measurement data. The results of this analysis are also presented in the paper.

Plötner, Peter; Czupalla, M. Markus; Zhukov, Anton

2012-07-01

279

Bloom's Taxonomy of the Cognitive Domain  

NSDL National Science Digital Library

This webpage explains Bloom's Taxonomy, and also features ideas for revising and rethinking the ordering of the steps in the hierarchy. A copy of Bloom's Taxonomy with sample verbs and a sample behavior statement for each level is also included.

W. Huitt

280

Phytoplankton Blooms and Ocean Warming  

NSDL National Science Digital Library

In this problem-based learning module, learners study phytoplankton blooms along the U.S. coast. Phytoplankton form the basis of the marine food web, regulate carbon in the atmosphere, and are responsible for half of the photosynthesis that takes place on the planet. Studying phytoplankton blooms is one way that scientists monitor the effects of climate change. Instructions are provided to access NASA data along with additional resources and activities. This module was developed to be used in the Earth System Science Education Alliance (ESSEA) courses for middle and high school teachers and is also available to teachers to adapt for general classroom use.

281

Human factors assessments of the STS-57 SpaceHab-1 mission  

NASA Technical Reports Server (NTRS)

SpaceHab-1 (STS-57) was the first of six scheduled Commercial Middeck Augmentation Module (CMAM) missions seeking to offer entrepreneurial companies an opportunity to use the resource of microgravity. The SpaceHab module, which occupies about one-fourth of the payload bay, is approximately 2-3/4 meters (9 feet) long and 4 meters (13.5 feet) in diameter. It provides a shirt-sleeve working environment and contains the storage space equivalent of 50 middeck lockers, considerably over and above the number of experiments that can be carried in the orbiter middeck alone. A modified Spacelab tunnel links the SpaceHab module to the middeck. While in orbit, the orbiter payload bay doors remain open, exposing the padded exterior of the lab and tunnel to space until preparation for reentry at the end of the flight. The crew for SpaceHab-1 was comprised of four males and two females, each of whom participated in some part of the human factors assessment (HFA) evaluation. The HFA was one of over twenty experiments manifested on this maiden flight of the SpaceHab module. HFA consisted of HFA-EPROC, HFA-LIGHT, HFA-SOUND, HFA-QUEST, and HFA-TRANS. The goal of HFA-EPROC was to assess the advantages and disadvantages of paper versus computer presentation for procedural tasks. The next two evaluations investigated the module's lighting and acoustic environment. HFA-TRANS sought to evaluate the design of the SpaceHab tunnel and to characterize translation through it. HFA-QUEST represented a consolidation of the in-flight questions generated by the HFA principal investigators involved in the acoustic, lighting, and translation studies.

Mount, Frances E.; Adam, Sue; Mckay, Tim; Whitmore, Mihriban; Merced-Moore, Darlene; Holden, Tina; Wheelwright, Charles; Koros, Anton, Sr.; Oneal, Michael; Toole, Jennifer

1994-01-01

282

The Bloom Paradox: When not to Use a Bloom Filter?  

E-print Network

Filters (CBFs), and depends on the product of the hashed counters of each element. In addition, both, security, and differentiated services [1]­[5]. Bloom filters are probabilistic data structures that can the main memory with a fixed cost of 10. Second, to look for it in the cache. With some probability

Keslassy, Isaac

283

Dramatic blooms of Prymnesium sp. and Alexandrium margalefii in the Salton Sea, California  

NASA Astrophysics Data System (ADS)

In early 2006, unusual algal blooms of two species occurred in the Salton Sea, a large salt lake in southern California. In mid-January local residents reported bioluminescence in the Sea. Starting in February, large rafts of long-lasting foam, also bioluminescent, were observed as well. Microscopy investigations on water and sediment samples collected in March showed the marine dinoflagellate, Alexandrium margalefii, and the prymnesiophyte, Prymnesium sp., both previously unreported in the Salton Sea, to be abundant. Bioluminescence and foam production continued through March. Other dinoflagellate species, recorded during earlier studies, were rare or not detected during these blooms. Despite the fact that many Alexandrium species are known paralytic shellfish poison (PSP) producers, preliminary saxitoxin tests on this population of A. margalefii were negative. Previous reports on A. margalefii do not mention bioluminescence. It appears that the foam was caused by the Prymnesium sp. bloom, probably via protein-rich exudates and lysis of other algal cells, and its glow was due to entrained A. margalefii. This is the first report of A. margalefii in U.S. waters and the first report of it in a lake.

Tiffany, Mary A.; Wolny, Jennifer; Garrett, Matthew; Steidinger, Karen; Hurlbert, Stuart H.

2008-08-01

284

Intraspecific variability in Karlodinium veneficum: Growth rates, mixotrophy, and lipid composition  

Microsoft Academic Search

We isolated eleven strains of the harmful algal bloom (HAB)-forming dinoflagellate Karlodinium veneficum during a bloom event in the NW Mediterranean coastal waters and we studied the inter-strain variability in several of their physiological and biochemical traits. These included autotrophic growth parameters, feeding capabilities (mixotrophy), lipid composition, and, in some cases, their responses to biotic and abiotic factors. The strains

Albert Calbet; Mireia Bertos; Claudio Fuentes-Grünewald; Elisabet Alacid; Rosa Figueroa; Berta Renom; Esther Garcés

2011-01-01

285

Algal culture studies for CELSS  

NASA Technical Reports Server (NTRS)

Microalgae are well-suited as a component of a Closed Environmental Life Support System (CELSS), since they can couple the closely related functions of food production and atmospheric regeneration. The objective was to provide a basis for predicting the response of CELSS algal cultures, and thus the food supply and air regeneration system, to changes in the culture parameters. Scenedesmus growth was measured as a function of light intensity, and the spectral dependence of light absorption by the algae as well as algal respiration in the light were determined as a function of cell concentration. These results were used to test and confirm a mathematical model that describes the productivity of an algal culture in terms of the competing processes of photosynthesis and respiration. The relationship of algal productivity to cell concentration was determined at different carbon dioxide concentrations, temperatures, and light intensities. The maximum productivity achieved by an air-grown culture was found to be within 10% of the computed maximum productivity, indicating that CO2 was very efficiently removed from the gas stream by the algal culture. Measurements of biomass productivity as a function of cell concentration at different light intensities indicated that both the productivity and efficiency of light utilization were greater at higher light intensities.

Radmer, R.; Behrens, P.; Arnett, K.; Gladue, R.; Cox, J.; Lieberman, D.

1987-01-01

286

Comparison of the efficacy of MODIS and MERIS data for detecting cyanobacterial blooms in the southern Caspian Sea.  

PubMed

Medium Resolution Imaging Spectrometer (MERIS) data, Moderate Resolution Imaging Spectroradiometer (MODIS) data, and hydro-biological measurements were used to detect two very severe blooms in the southern Caspian Sea in 2005 and 2010. The MERIS Cyanobacteria Index (CIMERIS) was more reliable for detecting cyanobacterial blooms. The CIMERIS and MODIS cyanobacteria indices (CIMODIS) were compared in an effort to find a reliable method for detecting future blooms, as MERIS data were not available after April 2012. The CIMODIS had a linear relationship with and similar spatial patterns to the CIMERIS. On the CIMODIS images, extremely high biomass cyanobacteria patches were masked. A comparison of classified in situ data with the CIMODIS and Floating Algal Index (FAI) from four images of a severe bloom event in 2005 showed that the FAI is a reliable index for bloom detection over extremely dense patches. The corrected CIMODIS, the MODIS FAI and in situ data are adequate tools for cyanobacterial bloom monitoring in the southern Caspian Sea. PMID:25148755

Moradi, Masoud

2014-10-15

287

Reflections on Bloom's Revised Taxonomy  

ERIC Educational Resources Information Center

In the application of the "Original" Bloom's taxonomy since its publication in 1956, several weaknesses and practical limitations have been revealed. Besides, psychological and educational research has witnessed the introduction of several theories and approaches to learning which make students more knowledgeable of and responsible for their own…

Amer, Aly

2006-01-01

288

In situ Monitoring of Cyanobacterial HABs in Western Lake Erie using Buoy-mounted Sensors  

E-print Network

In situ Monitoring of Cyanobacterial HABs in Western Lake Erie using Buoy-mounted Sensors Primary for the rest of the western basin of Lake Erie. We propose to deploy environmental sensors at these sites. The first sensor is a fluorescence-based detector of phycocyanin, a pigment found predominantly

289

Interior of the first level facing opposite photo HABS HI5064 ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior of the first level facing opposite photo HABS HI-506-4 - U.S. Naval Base, Pearl Harbor, Dry Dock No. 4, East & West Pumpwells, Near south end of Third Street, at east & west sides of Dry Dock No. 4, Pearl City, Honolulu County, HI

290

A review of ocean color remote sensing methods and statistical techniques for the detection, mapping and analysis of phytoplankton blooms in coastal and open oceans  

NASA Astrophysics Data System (ADS)

The need for more effective environmental monitoring of the open and coastal ocean has recently led to notable advances in satellite ocean color technology and algorithm research. Satellite ocean color sensors' data are widely used for the detection, mapping and monitoring of phytoplankton blooms because earth observation provides a synoptic view of the ocean, both spatially and temporally. Algal blooms are indicators of marine ecosystem health; thus, their monitoring is a key component of effective management of coastal and oceanic resources. Since the late 1970s, a wide variety of operational ocean color satellite sensors and algorithms have been developed. The comprehensive review presented in this article captures the details of the progress and discusses the advantages and limitations of the algorithms used with the multi-spectral ocean color sensors CZCS, SeaWiFS, MODIS and MERIS. Present challenges include overcoming the severe limitation of these algorithms in coastal waters and refining detection limits in various oceanic and coastal environments. To understand the spatio-temporal patterns of algal blooms and their triggering factors, it is essential to consider the possible effects of environmental parameters, such as water temperature, turbidity, solar radiation and bathymetry. Hence, this review will also discuss the use of statistical techniques and additional datasets derived from ecosystem models or other satellite sensors to characterize further the factors triggering or limiting the development of algal blooms in coastal and open ocean waters.

Blondeau-Patissier, David; Gower, James F. R.; Dekker, Arnold G.; Phinn, Stuart R.; Brando, Vittorio E.

2014-04-01

291

Weekly flow cytometric analysis of riverine phytoplankton to determine seasonal bloom dynamics.  

PubMed

Understanding the relative role of anthropogenic and environmental drivers on the timing, magnitude and composition of algal and cyanobacterial blooms is vitally important for the effective management of river catchments. Whilst taxonomic identification and enumeration of algal species can provide valuable insights, the time and specialist skills needed for this approach makes it prohibitive for high frequency and multiple-site studies. Other proxies for phytoplankton, such as total chlorophyll concentration provide little information on community composition. Here we demonstrate the use of flow cytometry (FCM) as a viable alternative approach for monitoring the changing seasonal patterns of abundance, composition and biovolume of phytoplankton in rivers. A FCM assay was set up and calibrated using a range of pure algal cultures and then applied to a year-long, weekly sampling campaign on the River Thames at Wallingford, UK. Ten groups of phytoplankton representing diatoms, chlorophytes, cryptophytes and cyanobacteria were monitored over the course of the year and examined in relation to river physiochemical parameters. Major diatom blooms occurred in spring and autumn, correlating with depletion of soluble reactive phosphorus and dissolved silicon concentrations and we also observed a significant and sustained cyanobacteria bloom between July and October. Pico-chlorophytes (0.2-2.0 ?m in diameter) dominated the community throughout the summer period but were not detected using traditional colorimetric chlorophyll analysis, suggesting underestimates of actual phytoplankton standing stocks by traditional methods. We demonstrate high resolution sampling and FCM as a sensitive method for river ecosystem monitoring and that FCM data may be used as an indicator of riverine health. PMID:24510006

Read, Daniel S; Bowes, Michael J; Newbold, Lindsay K; Whiteley, Andrew S

2014-03-01

292

Blooming Seas West of Ireland  

NASA Technical Reports Server (NTRS)

For several weeks in May and early June, daily satellite images of the North Atlantic Ocean west of Ireland have captured partial glimpses of luxuriant blooms of microscopic marine plants between patches of clouds. On June 4, 2007, the skies over the ocean cleared, displaying the sea's spring bloom in brilliant color. A bright blue bloom stretches north from the Mouth of the River Shannon and tapers off like a plume of blue smoke north of Clare Island. (In the large image, a second bloom is visible to the north, wrapping around County Donegal, on the island's northwestern tip.) The image was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. Cold, nutrient-stocked water often wells up to the surface from the deeper ocean along coastal shelves and at the edges of ocean currents. When it does, it delivers a boost of nutrients that fuel large blooms of single-celled plants collectively known as phytoplankton. The plants are the foundation of the marine food web, and their proliferation in this area of the North Atlantic explains why the waters of western Ireland support myriad fisheries and populations of large mammals like seals, whales, and dolphins. Like plants on land, phytoplankton make their food through photosynthesis, harnessing sunlight for energy using chlorophyll and other light-capturing pigments. The pigments change the way light reflects off the surface water, appearing as colorful swirls of turquoise and green against the darker blue of the ocean. Though individually tiny, collectively these plants play a big role in Earth's carbon and climate cycles; worldwide, they remove about as much carbon dioxide from the atmosphere during photosynthesis as land plants do. Satellites are the only way to map the occurrence of phytoplankton blooms across the global oceans on a regular basis. That kind of information is important not only to scientists who model carbon and climate, but also to biologists and fisheries managers who monitor the health of marine natural resources like coral reefs and fish populations.

2007-01-01

293

Isolation and structures of microcystins from a cyanobacterial water bloom (Finland).  

PubMed

A hepatotoxic cyanobacterial (blue-green algal) water bloom was collected from a constructed water reservoir in Finland. The water bloom contained two cyanobacterial species, Microcystis aeruginosa and Aphanizomenon flos-aquae. Two hepatotoxins, 1 and 2, were isolated from extracts of lyophilized cells. The structures of 1 and 2 were assigned based upon their amino acid analyses on a Waters Pico Tag HPLC system and a chiral GC capillary column (Chirasil Val III), fast atom bombardment mass spectrometry (FABMS), high resolution FABMS, and tandem FABMS data. Toxin 1 was identical to a previously reported compound, [D-Asp3]microcystin-RR. Toxin 2 was new and was assigned the structure [D-Asp3]microcystin-YR. PMID:1485342

Namikoshi, M; Sivonen, K; Evans, W R; Sun, F; Carmichael, W W; Rinehart, K L

1992-11-01

294

Climate anomalies generate an exceptional dinoflagellate bloom in San Francisco Bay  

USGS Publications Warehouse

We describe a large dinoflagellate bloom, unprecedented in nearly three decades of observation, that developed in San Francisco Bay (SFB) during September 2004. SFB is highly enriched in nutrients but has low summer-autumn algal biomass because wind stress and tidally induced bottom stress produce a well mixed and light-limited pelagic habitat. The bloom coincided with calm winds and record high air temperatures that stratified the water column and suppressed mixing long enough for motile dinoflagellates to grow and accumulate in surface waters. This event-scale climate pattern, produced by an upper-atmosphere high-pressure anomaly off the U.S. west coast, followed a summer of weak coastal upwelling and high dinoflagellate biomass in coastal waters that apparently seeded the SFB bloom. This event suggests that some red tides are responses to changes in local physical dynamics that are driven by large-scale atmospheric processes and operate over both the event scale of biomass growth and the antecedent seasonal scale that shapes the bloom community. Copyright 2005 by the American Geophysical Union.

Cloern, J.E.; Schraga, T.S.; Lopez, C.B.; Knowles, N.; Grover, Labiosa R.; Dugdale, R.

2005-01-01

295

Shallow water processes govern system-wide phytoplankton bloom dynamics: A modeling study  

USGS Publications Warehouse

A pseudo-two-dimensional numerical model of estuarine phytoplankton growth and consumption, vertical turbulent mixing, and idealized cross-estuary transport was developed and applied to South San Francisco Bay. This estuary has two bathymetrically distinct habitat types (deep channel, shallow shoal) and associated differences in local net rates of phytoplankton growth and consumption, as well as differences in the water column's tendency to stratify. Because many physical and biological time scales relevant to algal population dynamics decrease with decreasing depth, process rates can be especially fast in the shallow water. We used the model to explore the potential significance of hydrodynamic connectivity between a channel and shoal and whether lateral transport can allow physical or biological processes (e.g. stratification, benthic grazing, light attenuation) in one sub-region to control phytoplankton biomass and bloom development in the adjacent sub-region. Model results for South San Francisco Bay suggest that lateral transport from a productive shoal can result in phytoplankton biomass accumulation in an adjacent deep, unproductive channel. The model further suggests that turbidity and benthic grazing in the shoal can control the occurrence of a bloom system-wide; whereas, turbidity, benthic grazing, and vertical density stratification in the channel are likely to only control local bloom occurrence or modify system-wide bloom magnitude. Measurements from a related field program are generally consistent with model-derived conclusions. ?? 2008 Elsevier B.V.

Lucas, L.V.; Koseff, J.R.; Monismith, S.G.; Thompson, J.K.

2009-01-01

296

Dangerous jellyfish blooms are predictable.  

PubMed

The potentially fatal Irukandji syndrome is relatively common in tropical waters throughout the world. It is caused by the sting of the Irukandji jellyfish, a family of box jellyfish that are almost impossible to detect in the water owing to their small size and transparency. Using collated medical records of stings and local weather conditions, we show that the presence of Irukandji blooms in coastal waters can be forecast on the basis of wind conditions. On the Great Barrier Reef, blooms largely coincide with relaxation of the prevailing southeasterly trade winds, with average conditions corresponding to near zero alongshore wind on the day prior to the sting. These conditions are consistent with hypotheses long held by local communities and provide a basis for designing management interventions that have the potential to eliminate the majority of stings. PMID:24829278

Gershwin, Lisa-ann; Condie, Scott A; Mansbridge, Jim V; Richardson, Anthony J

2014-07-01

297

F-LE Algae Blooms  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Algae blooms routinely threaten the health of the Chesapeake Bay. Phosphate compounds supply a rich source of nutrients for the algae, Prorocentrum min...

298

HAb18G/CD147 Promotes pSTAT3-Mediated Pancreatic Cancer Development via CD44s †, ‡  

PubMed Central

Purpose STAT3 plays a critical role in initiation and progression of pancreatic cancer. However, therapeutically targeting STAT3 is failure in clinic. We previously identified HAb18G/CD147 as an effective target for cancer treatment. In this study, we aimed to investigate potential role of HAb18G/CD147 in STAT3-involved pancreatic tumorigenesis in vitro and in vivo. Experimental Design The expression of HAb18G/CD147, pSTAT3 and CD44s were determined in tissue microarrays. The tumorigenic function and molecular signaling mechanism of HAb18G/CD147 was assessed by in vitro cellular and clonogenic growth, reporter assay, immunoblot, immunofluorescence staining, immunoprecipitation, and in vivo tumor formationusing loss or gain-of-function strategies. Results Highly expressed HAb18G/CD147 promoted cellular and clonogenic growth in vitro and tumorigenicity in vivo. CyPA, a ligand of CD147, stimulated STAT3 phosphorylation and its downstream genes cyclin D1/survivin through HAb18G/CD147 dependent mechanisms. HAb18G/CD147 was associated and co-localized with cancer stem cell marker CD44s in lipid rafts. The inhibitors of STAT3 and survivin, as well as CD44s neutralizing antibodies suppressed the HAb18G/CD147-induced cell growth. High HAb18G/CD147 expression in pancreatic cancer was significantly correlated with the poor tumor differentiation, and the high co-expression of HAb18G/CD147-CD44s-STAT3 associated with poor survival of patients with pancreatic cancer. Conclusions We identified HAb18G/CD147 as a novel upstream activator of STAT3 via interacts with CD44s and plays a critical role in the development of pancreatic cancer. The data suggest HAb18G/CD147 could be a promising therapeutic target for highly aggressive pancreatic cancer and a surrogate marker in the STAT3-targeted molecular therapies. PMID:24132924

Li, Ling; Tang, Wenhua; Wu, Xiaoqing; Karnak, David; Meng, Xiaojie; Thompson, Rachel; Hao, Xinbao; Li, Yongmin; Qiao, Xiaotan T.; Lin, Jiayuh; Fuchs, James; Simeone, Diane M.; Chen, Zhi-Nan; Lawrence, Theodore S.; Xu, Liang

2013-01-01

299

Growth of heterotrophic bacteria and algal extracellular products in oligotrophic waters.  

PubMed

The unexpected observation of 200 to 400 coliform bacteria per 100 ml in an unpolluted pristine stream was studied within Grand Teton National Park, Wyo. The high numbers of waterborne bacteria occurred in mid- to late summer at a location where there was a coincidental bloom of an algal mat community. Periphyton samplers were used to measure the algal growth that coincided with the increase in number of bacteria. Laboratory studies followed the growth of various coliform bacteria in the supernatant obtained from a Chlorella culture isolated from the mat community. Mixed natural bacterial populations from the stream and pure cultures of water-isolated fecal and nonfecal coliforms increased by two to three orders of magnitude at 13 degrees C when grown in the algal supernatant. Radioactive algal products were obtained by feeding an axenic Chlorella culture C-labeled bicarbonate under laboratory cultivation at 13 degrees C with illumination. Radioactive organic material from the algae became incorporated into the particulate fraction of pure cultures of coliform bacteria as they reproduced and was later released as they died. PMID:16345278

McFeters, G A; Stuart, S A; Olson, S B

1978-02-01

300

Coccolithophorid blooms in the global ocean  

NASA Technical Reports Server (NTRS)

The global distribution pattern of coccolithophrid blooms was mapped in order to ascertain the prevalence of these blooms in the world's oceans and to estimate their worldwide production of CaCO3 and dimethyl sulfide (DMS). Mapping was accomplished by classifying pixels of 5-day global composites of coastal zone color scanner imagery into bloom and nonbloom classes using a supervised, multispectral classification scheme. Surface waters with the spectral signature of coccolithophorid blooms annually covered an average of 1.4 x 10(exp 6) sq km in the world oceans from 1979 to 1985, with the subpolar latitudes accounting for 71% of this surface area. Classified blooms were most extensive in the Subartic North Atlantic. Large expanses of the bloom signal were also detected in the North Pacific, on the Argentine shelf and slope, and in numerous lower latitude marginal seas and shelf regions. The greatest spatial extent of classified blooms in subpolar oceanic regions occurred in the months from summer to early autumn, while those in lower latitude marginal seas occurred in midwinter to early spring. Though the classification scheme was effcient in separating bloom and nonbloom classes during test simulations, and biogeographical literature generally confirms the resulting distribution pattern of blooms in the subpolar regions, the cause of the bloom signal is equivocal in some geographic areas, particularly on shelf regions at lower latitudes. Standing stock estimates suggest that the presumed Emiliania huxleyi blooms act as a significant source of calcite carbon and DMS sulfur on a regional scale. On a global scale, however, the satellite-detected coccolithophorid blooms are estimated to play only a minor role in the annual production of these two compounds and their flux from the surface mixed layer.

Brown, Christopher W.; Yoder, James A.

1994-01-01

301

Support Vector Machine-based method for predicting Pseudo-nitzschia spp. blooms in coastal waters (Galician rias, NW Spain)  

NASA Astrophysics Data System (ADS)

Phytoplanktonic blooms in the coastal embayments (rias) at the NW part of Spain were mentioned for the first time in 1918 and since then they have been associated numerous times with negatives impacts to a very important economic activity in the area, mussel production. In this study, eight years of Pseudo-nitzschia spp. abundance and associated meteorological and oceanographic data were used to develop and validate support vector machine (SVM) models for the prediction of these diatoms. SVM were used to identify presence/below low detection limit, bloom/no bloom conditions of Pseudo-nitzschia spp. and finally to predict blooms due to these diatoms in the coastal systems of the Galician rias. The best SVM models were selected on the basis of C and ? parameters and their performance was evaluated in terms of accuracy and kappa statistics (?). Regarding the presence/below low detection limit, bloom/no bloom models the best results in the validation dataset were achieved using all the variables: ria code, day of the year, temperature, salinity, upwelling indices and bloom occurrence in previous weeks. The best performing models were also tested in an independent dataset from the study area, where they showed high overall accuracy (78.53-82.18%), ? values (0.77-0.81) and true positive rates (62.60-78.18). In these models the bloom occurrence in previous weeks was identified as a key parameter to the prediction performance. In this paper, toxic Pseudo-nitzschia blooms could not be predicted due to limited information on toxin concentration and species composition. Nevertheless, this study demonstrates that the approach followed here is capable for high predictive performance which could be of great aid in the monitoring of algal blooms and offer valuable information to the local shellfish industry. The reliable prediction of categorical Pseudo-nitzschia abundances using variables that are operationally determined or short-term predicted could provide early warning of an impending bloom and could help to the development of strategies that could minimize the risks to human health and protect valuable economic resources.

González Vilas, Luis; Spyrakos, Evangelos; Torres Palenzuela, Jesus M.; Pazos, Yolanda

2014-05-01

302

Hatch Integration Testing of a NASA TransHab Derivative Woven Inflatable Module  

NASA Technical Reports Server (NTRS)

Current options for Lunar habitat architecture include inflatable habitats and airlocks. Inflatable structures can have mass and volume advantages over conventional structures. However, inflatable structures are also perceived to carry additional risk because they are at a lower Technical Readiness Level (TRL) than more conventional metallic structures. The use of inflatable structures for habitation will require large penetrations in the inflatable structure to accommodate hatches and/or windows The Hatch Integration Test is designed to study the structural integrity of an expandable structure with an integrated hatch, and to verify mathematical models of the structure. The TransHab project developed an experimental inflatable module at Johnson Space Center in the 1990's. The TransHab design was originally envisioned for use in Mars Transits but was also studied as a potential habitat for the International Space Station (ISS).

Edgecombe, John; Valle, Gerald

2009-01-01

303

HAb18G/CD147 is involved in TGF-?-induced epithelial-mesenchymal transition and hepatocellular carcinoma invasion.  

PubMed

Epithelial-mesenchymal transition (EMT) induced by the transforming growth factor beta (TGF-?) is involved in hepatocarcinogenesis and hepatocellular carcinoma (HCC) metastasis. HAb18G/CD147, a member of the immunoglobulin family, plays an important role in tumor invasion and metastasis. HAb18G/CD147 promotes EMT of hepatocytes through TGF-? signaling and is transcriptionally regulated by Slug. We investigated the role of HAb18G/CD147 in TGF-?-induced EMT in HCC invasion. Two human HCC cell lines, SMMC-7721 and HepG2, were used to determine the role of HAb18G/CD147 in EMT. Upregulation of HAb18G/CD147 induced by the high doses of TGF-?1 in SMMC-7721 (5?ng/mL) and HepG2 cells (10?ng/mL) (P?HAb18G/CD147 is involved in TGF-?-induced EMT and HCC invasion. PMID:25044444

Ru, Ning-Yu; Wu, Jiao; Chen, Zhi-Nan; Bian, Huijie

2015-01-01

304

The HABS Culture of Documentation with an Analysis of Drawing and Technology  

E-print Network

of drawings of the Ebenezer Maxwell Mansion in Philadelphia to Princess Grace of Monaco as the basis for construction of a replica for her children.18 HABS uses measured drawings to cultivate awareness for cultural heritage. In this context, Lavoie said..., by Indiana University Press, 1983), 2. 18 Elise Vider, ?The Historic American Buildings Survey in Philadelphia, 1950-1966: Shaping Postwar Preservation? (Thesis (MS in Historic Preservation), Graduate School of Arts and Sciences, University...

Akboy, Serra

2012-02-14

305

Hunting Dangerous Algae from Space  

NSDL National Science Digital Library

This NASA Earth Observatory article presents information about programs that are monitoring red tide and other harmful algal bloom (HAB) outbreaks from satellite imagery and remote sensing. This program uses SeaWiFS (Sea-viewing Wide Field-of-view Sensor) and MODIS (Moderate Resolution Imaging Spectroradiometer) instruments to detect harmful algal blooms from space. The article features satellite images and color photos of red tide and HAB occurrences. It also features a glossary on/off function in which readers can choose to have terms highlighted and linked to a corresponding glossary.

Evelyne Yohe

306

Air pollutant production by algal cell cultures  

NASA Technical Reports Server (NTRS)

The production of phytotoxic air pollutants by cultures of Chlorella vulgaris and Euglena gracilis is considered. Algal and plant culture systems, a fumigation system, and ethylene, ethane, cyanide, and nitrogen oxides assays are discussed. Bean, tobacco, mustard green, cantaloupe and wheat plants all showed injury when fumigated with algal gases for 4 hours. Only coleus plants showed any resistance to the gases. It is found that a closed or recycled air effluent system does not produce plant injury from algal air pollutants.

Fong, F.; Funkhouser, E. A.

1982-01-01

307

H2O2 inhibits ABA-signaling protein phosphatase HAB1.  

PubMed

Due to its ability to be rapidly generated and propagated over long distances, H2O2 is an important second messenger for biotic and abiotic stress signaling in plants. In response to low water potential and high salt concentrations sensed in the roots of plants, the stress hormone abscisic acid (ABA) activates NADPH oxidase to generate H2O2, which is propagated in guard cells in leaves to induce stomatal closure and prevent water loss from transpiration. Using a reconstituted system, we demonstrate that H2O2 reversibly prevents the protein phosphatase HAB1, a key component of the core ABA-signaling pathway, from inhibiting its main target in guard cells, SnRK2.6/OST1 kinase. We have identified HAB1 C186 and C274 as H2O2-sensitive thiols and demonstrate that their oxidation inhibits both HAB1 catalytic activity and its ability to physically associate with SnRK2.6 by formation of intermolecular dimers. PMID:25460914

Sridharamurthy, Madhuri; Kovach, Amanda; Zhao, Yang; Zhu, Jian-Kang; Xu, H Eric; Swaminathan, Kunchithapadam; Melcher, Karsten

2014-01-01

308

H2O2 Inhibits ABA-Signaling Protein Phosphatase HAB1  

PubMed Central

Due to its ability to be rapidly generated and propagated over long distances, H2O2 is an important second messenger for biotic and abiotic stress signaling in plants. In response to low water potential and high salt concentrations sensed in the roots of plants, the stress hormone abscisic acid (ABA) activates NADPH oxidase to generate H2O2, which is propagated in guard cells in leaves to induce stomatal closure and prevent water loss from transpiration. Using a reconstituted system, we demonstrate that H2O2 reversibly prevents the protein phosphatase HAB1, a key component of the core ABA-signaling pathway, from inhibiting its main target in guard cells, SnRK2.6/OST1 kinase. We have identified HAB1 C186 and C274 as H2O2-sensitive thiols and demonstrate that their oxidation inhibits both HAB1 catalytic activity and its ability to physically associate with SnRK2.6 by formation of intermolecular dimers. PMID:25460914

Sridharamurthy, Madhuri; Kovach, Amanda; Zhao, Yang; Zhu, Jian-Kang; Xu, H. Eric; Swaminathan, Kunchithapadam; Melcher, Karsten

2014-01-01

309

Structural Dynamics of Community Gene Expression In a Freshwater Cyanobacterial Bloom Over a Day-Night Cycle  

NASA Astrophysics Data System (ADS)

Cyanobacterial blooms are a major problem in eutrophic lakes and reservoirs, negatively impacting the ecology of the water body through oxygen depletion upon bloom decay and in some cases through production of toxins. Waterborne cyanobacterial toxins pose a public health threat through drinking and recreational exposure. The frequency of harmful cyanobacterial blooms (cyanoHABs) is predicted to increase due to warming regional climates (Paerl et.al, 2011) and increases in non-point source pollution due to urban expansion (Novotny, 2011). CyanoHABs represent complex consortia of cyanobacteria that live in association with diverse assemblages of heterotrophic and anoxygenic photosynthetic bacteria. A better understanding of the structure, function, and interaction between members of the complex microbial communities that support the proliferation of toxigenic cyanobacteria will improve our ability to prevent and control cyanoHABs. Studies of community gene expression, or metatranscriptomics, provide a powerful approach for quantifying changes in both the taxonomic composition (structure) and activity (function) of complex microbial systems in response to dynamic environmental conditions. We have used next-generation Illumina sequencing to characterize the metatranscriptome of a tropical eutrophic drinking water reservoir dominated by the toxigenic cyanobacterium Microcystis aeruginosa over a day/night cycle. Bacterioplankton sampling was carried out at six time points over a 24 hour period to capture variability associated with changes in the balance between phototrophic and heterotrophic activity. Total RNA was extracted and subjected to ribosomal depletion followed by cDNA synthesis and sequencing, generating 493,468 to 678,064 95-101 bp post-quality control reads per sample. Hierarchical Clustering of transcriptional profiles supported sorting of samples into two clusters corresponding to "day" and "night" collection times. Annotation of reads through the MG-RAST pipeline (Metagenomics- Rapid Annotation using Subsystem Technology) reveals that the community taxonomic composition stays relatively constant throughout the day/night cycle and is dominated by transcripts with highest identity to members of the phyla Cyanobacteria, Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes (in decreasing order) where Microcystis transcripts represent 15.3 to 25.6% of the total bacterial transcriptomes (Eave=1E-4.22). Community transcripts are enriched with genes from the photosynthesis KEGG pathway during the day. In contrast, Proteobacterial transcripts are enriched at night (20.4% of the total bacterial transcriptome compared to 14.3% in the day, p = 0.039), and reveal signatures of heterotrophic activities. Metatranscriptomic quantification of microbial community gene expression in a cyanobacterial bloom dominated by Microcystis aeruginosa contributes to a fundamental understanding of nutrient and energy cycling over a day/night cycle and will enable better management and control of these cyanoHABs. Reference: Paerl HW et.al, (2011) Sci Total Environ.409(10):1739-45. Novotny V. (2011) Journal of Water Sustainability.1(1):1-22.

Wang, J.; Fernando, S.; Thompson, J. R.

2011-12-01

310

Satellite detection of phytoplankton export from the mid-Atlantic bight during the 1979 spring bloom  

NASA Astrophysics Data System (ADS)

Analysis of CZCS imagery confirms shipboard and in situ moored fluorometer observations of resuspension of near-bottom chlorophyll within surface waters (1-10 m) by northwesterly wind events in the mid-Atlantic Bight. As much as 8-16 ?g Chl l -1 are found during these wind events from March to May, with a seasonal increase of algal biomass until onset of stratification of the water column. Rapid sinking or downwelling apparently occurs after subsequent wind events, however, such that the predominant surface chlorophyll patterns is ?0.5-1.5 ?g l -1 over the continental shelf during most of the spring bloom. Perhaps half of the chlorophyll increase observed by satellite during a wind resuspension event represents in situ production during that 4-5 day interval, with the remainder attributed to accumulation of algal biomass previously produced and temporarily stored within near-bottom water. Present calculations suggest that at least 10% of the primary production of the spring bloom may be exported as ungrazed phytoplankton carbon from mid-Atlantic shelf waters to those of the continental slope.

Walsh, John J.; Dieterle, Dwight A.; Esaias, Wayne E.

1987-06-01

311

Satellite detection of phytoplankton export from the mid-Atlantic Bight during the 1979 spring bloom  

NASA Technical Reports Server (NTRS)

Analysis of Coastal Zone Color Scanner (CZCS) imagery confirms shipboard and in situ moored fluorometer observations of resuspension of near-bottom chlorophyll within surface waters (1 to 10 m) by northwesterly wind events in the mid-Atlantic Bight. As much as 8 to 16 micrograms chl/l are found during these wind events from March to May, with a seasonal increase of algal biomass until onset of stratification of the water column. Rapid sinking or downwelling apparently occurs after subsequent wind events, however, such that the predominant surface chlorophyll pattern is approx. 0.5 to 1.5 micrograms/l over the continental shelf during most of the spring bloom. Perhaps half of the chlorophyll increase observed by satellite during a wind resuspension event represents in-situ production during the 4 to 5 day interval, with the remainder attributed to accumulation of algal biomass previously produced and temporarily stored within near-bottom water. Present calculations suggest that about 10% of the primary production of the spring bloom may be exported as ungrazed phytoplankton carbon from mid-Atlantic shelf waters to those of the continental slope.

Walsh, J. J.; Dieterle, D. A.; Esaias, W. E.

1986-01-01

312

Sustainability of algal biofuel production using integrated renewable energy park (IREP) and algal biorefinery approach  

Microsoft Academic Search

Algal biomass can provide viable third generation feedstock for liquid transportation fuel. However, for a mature commercial industry to develop, sustainability as well as technological and economic issues pertinent to algal biofuel sector must be addressed first. This viewpoint focuses on three integrated approaches laid out to meet these challenges. Firstly, an integrated algal biorefinery for sequential biomass processing for

Bobban G. Subhadra

2010-01-01

313

Artificial mixing of lake water by bubble plume and effects of bubbling operations on algal bloom  

Microsoft Academic Search

In order to develop a method of predicting and assessing lake eutrophication, which is a serious environmental problem, and to propose effective measures for improvement of water quality, this paper presents a composite model of the mixing of lake water by air bubble plume and lake phytoplankton model. The equations of heat and mass transfer in the lake were solved

Monzur Alam Imteaz; Takashi Asaeda

2000-01-01

314

TESTING AND APPLICATION OF BIOMONITORING METHODS FOR ASSESSING ENVIRONMENTAL EFFECTS OF NOXIOUS ALGAL BLOOMS  

EPA Science Inventory

A major goal of the U.S. Environmental Protection Agency's Biomonitoring research program is to produce test methods to assess environmental effects of anthropogenic activities in marine waters (Phelps et al., 1987). n support of EPA Region II involvement in the "Brown Tide Compr...

315

Impacts of climate variability and future climate change on harmful algal blooms and human health  

Microsoft Academic Search

Anthropogenically-derived increases in atmospheric greenhouse gas concentrations have been implicated in recent climate change, and are projected to substantially impact the climate on a global scale in the future. For marine and freshwater systems, increasing concentrations of greenhouse gases are expected to increase surface temperatures, lower pH, and cause changes to vertical mixing, upwelling, precipitation, and evaporation patterns. The potential

Stephanie K Moore; Vera L Trainer; Nathan J Mantua; Micaela S Parker; Edward A Laws; Lorraine C Backer; Lora E Fleming

2008-01-01

316

OPTICAL MONITORING AND FORECASTING SYSTEMS FOR HARMFUL ALGAL BLOOMS: POSSIBILITY OR PIPE DREAM? (R827085)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

317

OPTICAL MONITORING AND FORECASTING SYSTEMS FOR HARMFUL ALGAL BLOOMS: POSSIBILITY OR PIPE DREAM? (R825243)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

318

Harmful algal bloom species and phosphate-processing effluent: Field and laboratory studies  

E-print Network

Tampa Bay Bioassay a b s t r a c t In 2002, the Florida Department of Environmental Protection began discharging phosphate-processing effluent into Bishop Harbor, an estuary within Tampa Bay. Because of concerns (Pittman, 1990). Florida phosphate companies employed almost 7000 people in the Tampa Bay area in 2001

Meyers, Steven D.

319

On Determining the Principal Source of Phosphorus Causing Summer Algal Blooms in Western Washington Lakes  

Microsoft Academic Search

Internal loading of total phosphorus (TP) calculated from mass balance averaged 68±21% of the total (internal + external) summer loading in 14 of 17 western Washington lakes that had internal loading. Moreover, whole-lake mean TP for the 16 lakes with complete mass balance data was 50 ±9 ?g·L, which was similar to TP (51±18 ?g·L) predicted from summer internal P

Eugene B. Welch; Jean M. Jacoby

2001-01-01

320

HAb18G\\/CD147-mediated calcium mobilization and hepatoma metastasis require both C-terminal and N-terminal domains  

Microsoft Academic Search

HAb18G\\/CD147 is a heavily glycosylated protein containing two immunoglobulin superfamily domains. Our previous studies have indicated that overexpression of HAb18G\\/CD147 enhances metastatic potentials in human hepatoma cells by disrupting the regulation of store-operated Ca 2+ entry by nitric oxide (NO)\\/cGMP. In the present study, we investigated the structure-function of HAb18G\\/CD147 by transfecting truncated HAb18G\\/CD147 fragments into human 7721 hepatoma cells.

J. L. Jiang; H. C. Chan; Q. Zhou; M. K. Yu; X. Y. Yao; S. Y. Lam; H. Zhu; L. S. Ho; K. M. Leung; Z. N. Chen

2004-01-01

321

Visualizing "green oil" in live algal cells.  

PubMed

We report here that BODIPY 505/515, a green lipophilic fluorescent dye, serves as an excellent vital stain for the oil-containing lipid bodies of live algal cells. BODIPY 505/515 vital staining can be used in combination with fluorescent activated cell sorting to detect and isolate algal cells possessing high lipid content. PMID:20129108

Cooper, Mark Scott; Hardin, William Robert; Petersen, Timothy Wayne; Cattolico, Rose Ann

2010-02-01

322

Removal of cyanobacterial blooms in Taihu Lake using local soils. II. Effective removal of Microcystis aeruginosa using local soils and sediments modified by chitosan.  

PubMed

After sepiolite was modified with Fe3+ to increase its surface charge, the initial algal removal rate increased significantly, but its Q8h was not improved substantially at clay loadings below 0.1 g/L. Modification on netting and bridging properties of clays by either chitosan or polyacrylamide (PAM) dramatically increased flocculation (Q8h) of MA cells in freshwaters. Algal removal efficiencies of different solids, including Type III clays, local soils and sediments, were all improved to a similar level of >90% at a total loading of 0.011 g/L (contained 0.001 g/L chitosan) after they were modified with chitosan, making the idea of clearing up algal blooms using local soils/sediments possible. The mechanism of netting and bridging was confirmed to be the most important factor in improving the removal efficiency of cells, whereas clays also played important roles in the sedimentation of the floc. PMID:16213637

Zou, Hua; Pan, Gang; Chen, Hao; Yuan, Xianzheng

2006-05-01

323

The Closed Aquatic System AquaHab® as part of a CELSS for Exploration, Space and Earth Application  

NASA Astrophysics Data System (ADS)

AquaHab R is a small, self-sustaining closed microcosm, based on the former space shuttle payload C.E.B.A.S. (Closed Equilibrated Biological Aquatic System). AquaHab R contains on laboratory scale within 8 liters of water volume different groups of organisms (fish, snails, amphipods, plants). During the last years, it was developed to a system for the risk assessment of chemicals as well as an early warning tool for air and water contamination, major concerns during long-term stays in closed habitats for example on Earth's subsurface (deep sea) or later on the Moon or Mars. AquaHab R is now enhanced developed for exploratory missions having implemented an algae reactor system for biomass production etc.. During first tests, the transport of oxygen from the algae reactor into the AquaHab R was demonstrated successfully. In the common AquaHab R - bioreactor system, the different subsystems will serve for several tasks. In the AquaHab R - tank, the removal of waste water (mainly nutrients) as well as the production of some higher plants and fish as food source will be most beneficial; additionally the AquaHab R -tank is supporting astronauts psychological health recovery (home aquaria effect, taking care for pets). The beneficially output of the algae reactors will e.g. be the increased delivery of oxygen and metabolic products with application potential for humans (as e.g. vitamins, drug like acting substances) as well as being a food source in general and also the removal of carbon dioxide. Furthermore, specialized algae can also serve as early warning tool, as all the organisms in the AquaHab R do, or producing energy equivalents. The different subsystems will interact with each other to treat the products of humans being in the closed habitat in the most effective way. This new life support subsystem will be bioregenerative and sustainable in the meaning, that no material transport into the system is needed, and non-usable and maybe toxic end products won‘t be produced. This is of high interest also for life in the closed biosphere Earth. The implementation of an AquaHab R -based life support system in an overall bioregenerative life support system concept for closed habitats is aimed. OHB-System is pushing the development of such a closed aquatic life support system in several projects, dealing with the single elements of the system as well as with the overall integration. First breadboards are tested in R&D-projects and are proposed to study in closed habitat simulation programs. An overview of some subsystems and the actual status will be given at the assembly.

Slenzka, Klaus

324

[Standing crop and spatial distribution of meiofauna in Yellow Sea at late stage of Enteromorpha prolifera bloom in 2008].  

PubMed

An investigation was made on the standing crop, spatial distribution, sediment environment of meiofauna at 33 stations (including 22 stations in cold water mass area and 9 stations in Enteromorpha prolifera bloom area) in the Yellow Sea at the late stage of E. prolifera bloom in summer 2008. In this southern Yellow Sea area which was seriously impacted by the green algal bloom, the silt and clay contents in the sediments in 2008 had an obvious increase, compared with those in 2007, and the sediment chlorophyll-a and phaeophytin a contents in 2008 did not show obvious changes in cold water mass area but distinctly decreased in southern Jiangsu inshore area and Yangtze River estuary. Within the total 16 meiofaunal groups sorted, no marked variation was observed in their vertical distribution and in the contribution of each group to the total meiofauna. In 2008, the average abundance of meiofauna was (1375 +/- 793) ind x 10 cm(-2), and the biomass was (1203 +/- 707) micro x 10 cm(-2), both of which were decreased by about 1/3, compared with those in 2007. The meiofaunal standing crop was decreased more obviously in the stations heavily affected by the E. prolifera bloom, while that in the Yellow Sea cold water mass area was slightly increased, resulting in an unusual trend of meiofaunal standing crop decreasing from the central area of cold water mass to the inshore area in the southern Yellow Sea. By contrast, and as usual, the meiofaunal standing crop was increased from the cold water mass area to the inshore area in the northern Yellow Sea. Statistical analyses suggested that only the meiofaunal abundance had positive correlation with the salinity in the stations heavily affected by the green algal bloom. Our study indicated that macroalgal bloom obviously inhibited the standing crop of meiofauna in the inshore area. The decrease was not due to the deficiency of food concentration, but likely caused by the deposition and degradation of the E. prolifera bloom. PMID:21043127

Wu, Xiu-Qin; Xu, Kui-Dong; Yu, Zi-Shan; Yu, Ting-Ting; Meng, Zhao-Cui; Dai, Ren-Hai; Lei, Yan-Li

2010-08-01

325

Behavioral and physiological changes during benthic-pelagic transition in the harmful alga, Heterosigma akashiwo: potential for rapid bloom formation.  

PubMed

Many species of harmful algae transition between a motile, vegetative stage in the water column and a non-motile, resting stage in the sediments. Physiological and behavioral traits expressed during benthic-pelagic transition potentially regulate the timing, location and persistence of blooms. The roles of key physiological and behavioral traits involved in resting cell emergence and bloom formation were examined in two geographically distinct strains of the harmful alga, Heterosigma akashiwo. Physiological measures of cell viability, division and population growth, and cell fatty acid content were made using flow cytometry and gas chromatography - mass spectrometry techniques as cells transitioned between the benthic resting stage and the vegetative pelagic stage. Video-based tracking was used to quantify cell-level swimming behaviors. Data show increased temperature and light triggered rapid emergence from the resting stage and initiated cell swimming. Algal strains varied in important physiological and behavioral traits, including survivorship during life-stage transitions, population growth rates and swimming velocities. Collectively, these traits function as "population growth strategies" that can influence bloom formation. Many resting cells regained the up-swimming capacity necessary to cross an environmentally relevant halocline and the ability to aggregate in near-surface waters within hours after vegetative growth supporting conditions were restored. Using a heuristic model, we illustrate how strain-specific population growth strategies can govern the timescales over which H. akashiwo blooms form. Our findings highlight the need for identification and quantification of strain-specific physiological and behavioral traits to improve mechanistic understanding of bloom formation and successful bloom prediction. PMID:24124586

Tobin, Elizabeth D; Grünbaum, Daniel; Patterson, Johnathan; Cattolico, Rose Ann

2013-01-01

326

Behavioral and Physiological Changes during Benthic-Pelagic Transition in the Harmful Alga, Heterosigma akashiwo: Potential for Rapid Bloom Formation  

PubMed Central

Many species of harmful algae transition between a motile, vegetative stage in the water column and a non-motile, resting stage in the sediments. Physiological and behavioral traits expressed during benthic-pelagic transition potentially regulate the timing, location and persistence of blooms. The roles of key physiological and behavioral traits involved in resting cell emergence and bloom formation were examined in two geographically distinct strains of the harmful alga, Heterosigma akashiwo. Physiological measures of cell viability, division and population growth, and cell fatty acid content were made using flow cytometry and gas chromatography – mass spectrometry techniques as cells transitioned between the benthic resting stage and the vegetative pelagic stage. Video-based tracking was used to quantify cell-level swimming behaviors. Data show increased temperature and light triggered rapid emergence from the resting stage and initiated cell swimming. Algal strains varied in important physiological and behavioral traits, including survivorship during life-stage transitions, population growth rates and swimming velocities. Collectively, these traits function as “population growth strategies” that can influence bloom formation. Many resting cells regained the up-swimming capacity necessary to cross an environmentally relevant halocline and the ability to aggregate in near-surface waters within hours after vegetative growth supporting conditions were restored. Using a heuristic model, we illustrate how strain-specific population growth strategies can govern the timescales over which H. akashiwo blooms form. Our findings highlight the need for identification and quantification of strain-specific physiological and behavioral traits to improve mechanistic understanding of bloom formation and successful bloom prediction. PMID:24124586

Tobin, Elizabeth D.; Grünbaum, Daniel; Patterson, Johnathan; Cattolico, Rose Ann

2013-01-01

327

Damage Tolerance Testing of a NASA TransHab Derivative Woven Inflatable Module  

NASA Technical Reports Server (NTRS)

Current options for Lunar habitat architecture include inflatable habitats and airlocks. Inflatable structures can have mass and volume advantages over conventional structures. However, inflatable structures carry different inherent risks and are at a lower Technical Readiness Level (TRL) than more conventional metallic structures. One of the risks associated with inflatable structures is in understanding the tolerance to induced damage. The Damage Tolerance Test (DTT) is designed to study the structural integrity of an expandable structure. TransHab (Figure 1) was an experimental inflatable module developed at the NASA/Johnson Space Center in the 1990 s. The TransHab design was originally envisioned for use in Mars Transits but was also studied as a potential habitat for the International Space Station (ISS). The design of the TransHab module was based on a woven design using an Aramid fabric. Testing of this design demonstrated a high level of predictability and repeatability with analytical predictions of stresses and deflections. Based on JSC s experience with the design and analysis of woven inflatable structures, the Damage Tolerance Test article was designed and fabricated using a woven design. The DTT article was inflated to 45 psig, representing 25% of the ultimate burst pressure, and one of the one-inch wide longitudinal structural members was severed by initiating a Linear Shaped Charge (LSC). Strain gage measurements, at the interface between the expandable elements (straps) and the nonexpandable metallic elements for pre-selected longitudinal straps, were taken throughout pressurization of the module and strap separation. Strain gage measurements show no change in longitudinal strap loading at the bulkhead interface after strap separation indicating loads in the restraint layer were re-distributed local to the damaged area due to the effects of friction under high internal pressure loading. The test completed all primary objectives with better than expected results. This paper will discuss space inflatable structures, damage tolerance analysis, test results, and applicability to the Lunar architecture.

Edgecombe, John; delaFuente, Horacio; Valle, Gerard

2009-01-01

328

Amoebophrya spp. from the bloom-forming dinoflagellate Cochlodinium polykrikoides: parasites not nested in the "Amoebophrya ceratii complex".  

PubMed

Members of Amoebophrya ceratii complex are known to infect a number of free-living dinoflagellates including harmful algal bloom species. In August and October 2012, Amoebophrya infections during two bloom events of the dinoflagellate Cochlodinium polykrikoides were observed along southern coastal waters of Korea. Microscopic observations and molecular data revealed that two different Amoebophrya parasites infected the same host species. In addition, while one developed in the host's nucleus, the other in the host's cytoplasm. Phylogenetic analyses showed that the two parasites were not nested in the previously recognized "Amoebophrya ceratii complex clade", which contained sequences of parasites infecting numerous dinoflagellate species. Instead, they branched as sister taxa to the isolate (possibly Amoebophrya) from radiolarians Hexacontium gigantheum. Our result indicates that the two Amoebophrya parasites infecting C. polykrikoides may be different species from those inside the "complex." PMID:24612333

Kim, Sunju; Park, Myung Gil

2014-01-01

329

Effects of HAb18G/CD147 Knockout on Hepatocellular Carcinoma Cells In Vitro Using a Novel Zinc-Finger Nuclease-Targeted Gene Knockout Approach.  

PubMed

HAb18G/CD147 belongs to the immunoglobulin superfamily and predominantly functions as an inducer of matrix metalloproteinase secretion for tumor invasion and metastasis. This study was designed to investigate the effects of HAb18G/CD147 knockout on hepatocellular carcinoma cells using zinc-finger nuclease (ZFNs)-targeted gene knockout approach. The HCC cell line SMMC-7721 was used for ZFNs-targeted cleavage of the HAb18G/CD147 gene. RT-PCR and Western blot assays were used to detect HAb18G/CD147 expression. HAb18G phenotypic changes following HAb18G/CD147 knockout in SMMC-K7721 cells were assessed using tumor cell adhesion, invasion, migration and colony formation and flow cytometric assays. These data demonstrated that tumor cell adhesion, invasion, migration, and colony formation capabilities of SMMC-K7721 were significantly reduced compared to parental cells or SMMC-7721 with re-expression of HAb18G/CD147 protein transfected with HAb18G/CD147 cDNA. Moreover, knockout of HAb18G/CD147 expression also induced SMMC-K7721 cells to undergo apoptosis compared to SMMC-7721 and SMMC-R7721 (P < 0.01). Molecularly, protein expression of p53 was induced in these cells, but re-expression of HAb18G/CD147 reduced p53 levels in SMMC-R7721 cells, possibly through inhibition of the PI3K-Akt-MDM2 signaling pathway. The findings provide a novel insight into the mechanisms underlying HAb18G/CD147-induced progression of HCC cells. PMID:25308857

Li, Hong-Wei; Yang, Xiang-Min; Tang, Juan; Wang, Shi-Jie; Chen, Zhi-Nan; Jiang, Jian-Li

2014-10-12

330

Plankton communities and summertime declines in algal abundance associated with low dissolved oxygen in the Tualatin River, Oregon  

USGS Publications Warehouse

Phytoplankton populations in the Tualatin River in northwestern Oregon are an important component of the dissolved oxygen (DO) budget of the river and are critical for maintaining DO levels in summer. During the low-flow summer period, sufficient nutrients and a long residence time typically combine with ample sunshine and warm water to fuel blooms of cryptophyte algae, diatoms, green and blue-green algae in the low-gradient, slow-moving reservoir reach of the lower river. Algae in the Tualatin River generally drift with the water rather than attach to the river bottom as a result of moderate water depths, slightly elevated turbidity caused by suspended colloidal material, and dominance of silty substrates. Growth of algae occurs as if on a “conveyor belt” of streamflow, a dynamic system that is continually refreshed with inflowing water. Transit through the system can take as long as 2 weeks during the summer low-flow period. Photosynthetic production of DO during algal blooms is important in offsetting oxygen consumption at the sediment-water interface caused by the decomposition of organic matter from primarily terrestrial sources, and the absence of photosynthesis can lead to low DO concentrations that can harm aquatic life. The periods with the lowest DO concentrations in recent years (since 2003) typically occur in August following a decline in algal abundance and activity, when DO concentrations often decrease to less than State standards for extended periods (nearly 80 days). Since 2003, algal populations have tended to be smaller and algal blooms have terminated earlier compared to conditions in the 1990s, leading to more frequent declines in DO to levels that do not meet State standards. This study was developed to document the current abundance and species composition of phytoplankton in the Tualatin River, identify the possible causes of the general decline in algae, and evaluate hypotheses to explain why algal blooms diminish in midsummer. Plankton and water-quality sample data from 2006 to 2008 were combined with parts of a larger discrete-sample and continuous water-quality monitoring dataset and examined to identify patterns in water-quality and algal conditions since 1991, with a particular emphasis on 2003–08. Longitudinal plankton surveys were conducted in 2006–08 at six sites between river miles (RM) 24.5 and 3.4 at 2- to 3-week intervals, or 5–6 per season, and in-situ bioassay experiments were conducted in 2008 to examine the potential effects of wastewater treatment facility (WWTF) effluent and phosphorus additions on phytoplankton biomass and algal photosynthesis. Phytoplankton and zooplankton community composition, streamflow, and water-quality data were analyzed using multivariate statistical techniques to gain insights into plankton dynamics to determine what factors might be most tied to the abundance and characteristics of the phytoplankton assemblages, and identify possible causes of their declines. The connection between low-DO events and algal declines was clearly evident, as bloom crashes were nearly always followed by periods of low DO. Algal blooms occurred each year during 2006–08, producing maximum chlorophyll-a (Chl-a) values in June or July generally in the range of 50–80 micrograms per liter (µg/L). Bloom crashes and absence of sufficient algal photosynthesis in mid- to late-summer contributed to minimum DO concentrations that were less than the State standard of 6.5 milligrams per liter (mg/L) based on the 30-day mean daily concentration, for 62–74 days each year. At times, the absolute minimum State standard (4 mg/L DO) also was not met. To learn more about why low-DO events occurred, specific algal declines during 2003–08 were scrutinized to determine their likely causal factors. From this information, a series of hypotheses were formulated and evaluated in terms of their ability to explain recent declines in algal populations in the river in late summer. Meteorological, streamflow, turbidity, water temperature, and conductance conditions in the Tualatin River

Carpenter, Kurt D.; Rounds, Stewart A.

2013-01-01

331

Biomonitoring and risk assessment on earth and during exploratory missions using AquaHab ®  

NASA Astrophysics Data System (ADS)

Bioregenerative closed ecological life support systems (CELSS) will be necessary in the exploration context revitalizing atmosphere, waste water and producing food for the human CELSS mates. During these long-term space travels and stays far away from Earth in an hostile environment as well as far for example from any hospital and surgery potential, it will be necessary to know much more about chemical and drug contamination in the special sense and by human's themselves in detail. Additionally, there is a strong need on Earth for more relevant standardized test systems including aquatic ones for the prospective risk assessment of chemicals and drugs in general on a laboratory scale. Current standardized test systems are mono species tests, and thus do not represent system aspects and have reduced environmental relevance. The experience gained during the last years in our research group lead to the development of a self-sustaining closed aquatic habitat/facility, called AquaHab ® which can serve regarding space exploration and Earth application. The AquaHab ® module can be the home of several fish species, snails, plants, amphipods and bacteria. The possibility to use different effect endpoints with certain beneficial characteristics is the basis for the application of AquaHab ® in different fields. Influence of drugs and chemicals can be tested on several trophic levels and ecosystem levels; guaranteeing a high relevance for aquatic systems in the real environment. Analyses of effect parameters of different complexity (e.g. general biological and water chemical parameters, activity of biotransforming enzymes) result in broad spectra of sensitivity. Combined with residual analyses (including all metabolites), this leads to an extended prospective risk assessment of a chemical on Earth and in a closed Life Support System. The possibility to measure also sensitive "online" parameters (e.g. behavior, respiration/photosynthetic activity) enables a quick and sensitive effect analysis of water contaminants in respective environments. AquaHab ® is currently under development to an early warning biomonitoring system using genetically modified fish and green algae. The implementation of biosensors/biochip in addition is also discussed.

Slenzka, K.; Dünne, M.; Jastorff, B.

2008-12-01

332

Dynamics of cyanobacterial bloom formation during short-term hydrodynamic fluctuation in a large shallow, eutrophic, and wind-exposed Lake Taihu, China.  

PubMed

Short-term hydrodynamic fluctuations caused by extreme weather events are expected to increase worldwide because of global climate change, and such fluctuations can strongly influence cyanobacterial blooms. In this study, the cyanobacterial bloom disappearance and reappearance in Lake Taihu, China, in response to short-term hydrodynamic fluctuations, was investigated by field sampling, long-term ecological records, high-frequency sensors and MODIS satellite images. The horizontal drift caused by the dominant easterly wind during the phytoplankton growth season was mainly responsible for cyanobacterial biomass accumulation in the western and northern regions of the lake and subsequent bloom formation over relatively long time scales. The cyanobacterial bloom changed slowly under calm or gentle wind conditions. In contrast, the short-term bloom events within a day were mainly caused by entrainment and disentrainment of cyanobacterial colonies by wind-induced hydrodynamics. Observation of a westerly event in Lake Taihu revealed that when the 30 min mean wind speed (flow speed) exceeded the threshold value of 6 m/s (5.7 cm/s), cyanobacteria in colonies were entrained by the wind-induced hydrodynamics. Subsequently, the vertical migration of cyanobacterial colonies was controlled by hydrodynamics, resulting in thorough mixing of algal biomass throughout the water depth and the eventual disappearance of surface blooms. Moreover, the intense mixing can also increase the chance for forming larger and more cyanobacterial colonies, namely, aggregation. Subsequently, when the hydrodynamics became weak, the cyanobacterial colonies continuously float upward without effective buoyancy regulation, and cause cyanobacterial bloom explosive expansion after the westerly. Furthermore, the results of this study indicate that the strong wind happening frequently during April and October can be an important cause of the formation and expansion of cyanobacterial blooms in Lake Taihu. PMID:23677755

Wu, Tingfeng; Qin, Boqiang; Zhu, Guangwei; Luo, Liancong; Ding, Yanqing; Bian, Geya

2013-12-01

333

Women's Ways of Knowing Bloom's Taxonomy.  

ERIC Educational Resources Information Center

Discusses the historical background of Bloom's Taxonomy. Asserts that the Taxonomy contains elements of sex bias. Describes Women's Ways of knowing along with a comparison of the perspectives and implications of both approaches. (CFR)

Hogsett, Charlotte

1993-01-01

334

A Shielding Model for an Inflatable Vehicle, TransHab, and the Associated Astronaut Space Radiation Risk Assessment  

NASA Technical Reports Server (NTRS)

TransHab, a habitable inflatable structure, has been proposed as a possible module for the International Space Station that provides significant increase in the available volume compared with the US Hab module and fo r a human Mars mission . A study was undertaken to understand and provide design inputs for crew radiation exposures. The results show that the current design provides sufficient shielding to assure that the crew exposures are below the crew exposure limits currently adopted for the ISS. In addition, the shielding provides adequate protection from the largest solar particle events (SPEs) observed during the last 40 years.

Atwell, William; Badhwar, Gautam

2000-01-01

335

Inflatable Structures: Test Results and Development Progress Since TransHab  

NASA Technical Reports Server (NTRS)

JSC's TransHab project was the first successful development program to prove the viability of inflatable habitats for space applications. Although TransHab was cancelled in 2000, significant progress has been made this past year by JSC engineers. Since February 2005, the following test articles have been manufactured and tested: 1 - An 88-in diameter restraint layer was pressure-tested to failure and reached an ultimate pressure of 197psi. This test article demonstrated the ability to build a 35- foot diameter inflatable with a factor of safety of 4.0 at 10.2 psi. 2 - An 88-in diameter restraint layer with a window frame incorporated into the restraint layer was tested to failure and reached an ultimate pressure of 197 psi. This test article demonstrated the ability to incorporate windows and other structural penetrations in the woven restraint layer without reducing its strength. 3 - An 88-inch diameter folding demonstrator that includes a bladder, restraint layer, and all of the MMOD shell layers was manufactured and assembled. This test article demonstrated an improved and simplified shell assembly and folding technique which installs pre-folded shell sections in a controlled manner. 4 - Fifth-scale MMOD hypervelocity test articles have demonstrated fiberglass as a viable material for a MMOD bumper shield which is cheaper and more readily available than previously used materials. In addition, four different full-scale advanced shape inflatable mockups have been manufactured and evaluated for applications such as lunar habitats, airlocks, and transfer tunnels.

Johnson, Chris

2006-01-01

336

Eukaryotic algal phytochromes span the visible spectrum  

PubMed Central

Plant phytochromes are photoswitchable red/far-red photoreceptors that allow competition with neighboring plants for photosynthetically active red light. In aquatic environments, red and far-red light are rapidly attenuated with depth; therefore, photosynthetic species must use shorter wavelengths of light. Nevertheless, phytochrome-related proteins are found in recently sequenced genomes of many eukaryotic algae from aquatic environments. We examined the photosensory properties of seven phytochromes from diverse algae: four prasinophyte (green algal) species, the heterokont (brown algal) Ectocarpus siliculosus, and two glaucophyte species. We demonstrate that algal phytochromes are not limited to red and far-red responses. Instead, different algal phytochromes can sense orange, green, and even blue light. Characterization of these previously undescribed photosensors using CD spectroscopy supports a structurally heterogeneous chromophore in the far-red–absorbing photostate. Our study thus demonstrates that extensive spectral tuning of phytochromes has evolved in phylogenetically distinct lineages of aquatic photosynthetic eukaryotes. PMID:24567382

Rockwell, Nathan C.; Duanmu, Deqiang; Martin, Shelley S.; Bachy, Charles; Price, Dana C.; Bhattacharya, Debashish; Worden, Alexandra Z.; Lagarias, J. Clark

2014-01-01

337

Direct conversion of algal biomass to biofuel  

DOEpatents

A method and system for providing direct conversion of algal biomass. Optionally, the method and system can be used to directly convert dry algal biomass to biodiesels under microwave irradiation by combining the reaction and combining steps. Alternatively, wet algae can be directly processed and converted to fatty acid methyl esters, which have the major components of biodiesels, by reacting with methanol at predetermined pressure and temperature ranges.

Deng, Shuguang; Patil, Prafulla D; Gude, Veera Gnaneswar

2014-10-14

338

Cyanobacteria blooms produce teratogenic retinoic acids  

PubMed Central

Deformed amphibians have been observed in eutrophic habitats, and some clues point to the retinoic acids (RAs) or RA mimics. However, RAs are generally thought of as vertebrate-specific hormones, and there was no evidence that RAs exist in cyanobacteria or algae blooms. By analyzing RAs and their analogs 4-oxo-RAs in natural cyanobacteria blooms and cultures of cyanobacteria and algae, we showed that cyanobacteria blooms could produce RAs, which were powerful animal teratogens. Intracellular RAs and 4-oxo-RAs with concentrations between 0.4 and 4.2 × 102 ng/L were detected in all bloom materials, and extracellular concentrations measured in water from Taihu Lake, China, were as great as 2.0 × 10 ng/L, which might pose a risk to wildlife through chronic exposure. Further examination of 39 cyanobacteria and algae species revealed that 32 species could produce RAs and 4-oxo-RAs (1.6–1.4 × 103 ng/g dry weight), and the dominant cyanobacteria species in Taihu Lake, Microcystis flos-aquae and Microcystis aeruginosa, produced high amounts of RAs and 4-oxo-RAs with concentrations of 1.4 × 103 and 3.7 × 102 ng/g dry weight, respectively. Most genera of cyanobacteria that could produce RAs and 4-oxo-RAs, such as Microcystis, Anabaena, and Aphanizomenon, often occur dominantly in blooms. Production of RAs and 4-oxo-RAs by cyanobacteria was associated with species, origin location, and growth stage. These results represent a conclusive demonstration of endogenous production of RAs in freshwater cyanobacteria blooms. The observation of teratogenic RAs in cyanobacteria is evolutionarily and ecologically significant because RAs are vertebrate-specific hormones, and cyanobacteria form extensive and highly visible blooms in many aquatic ecosystems. PMID:22645328

Wu, Xiaoqin; Jiang, Jieqiong; Wan, Yi; Giesy, John P.; Hu, Jianying

2012-01-01

339

Cyanobacteria blooms produce teratogenic retinoic acids.  

PubMed

Deformed amphibians have been observed in eutrophic habitats, and some clues point to the retinoic acids (RAs) or RA mimics. However, RAs are generally thought of as vertebrate-specific hormones, and there was no evidence that RAs exist in cyanobacteria or algae blooms. By analyzing RAs and their analogs 4-oxo-RAs in natural cyanobacteria blooms and cultures of cyanobacteria and algae, we showed that cyanobacteria blooms could produce RAs, which were powerful animal teratogens. Intracellular RAs and 4-oxo-RAs with concentrations between 0.4 and 4.2 × 10(2) ng/L were detected in all bloom materials, and extracellular concentrations measured in water from Taihu Lake, China, were as great as 2.0 × 10 ng/L, which might pose a risk to wildlife through chronic exposure. Further examination of 39 cyanobacteria and algae species revealed that 32 species could produce RAs and 4-oxo-RAs (1.6-1.4 × 10(3) ng/g dry weight), and the dominant cyanobacteria species in Taihu Lake, Microcystis flos-aquae and Microcystis aeruginosa, produced high amounts of RAs and 4-oxo-RAs with concentrations of 1.4 × 10(3) and 3.7 × 10(2) ng/g dry weight, respectively. Most genera of cyanobacteria that could produce RAs and 4-oxo-RAs, such as Microcystis, Anabaena, and Aphanizomenon, often occur dominantly in blooms. Production of RAs and 4-oxo-RAs by cyanobacteria was associated with species, origin location, and growth stage. These results represent a conclusive demonstration of endogenous production of RAs in freshwater cyanobacteria blooms. The observation of teratogenic RAs in cyanobacteria is evolutionarily and ecologically significant because RAs are vertebrate-specific hormones, and cyanobacteria form extensive and highly visible blooms in many aquatic ecosystems. PMID:22645328

Wu, Xiaoqin; Jiang, Jieqiong; Wan, Yi; Giesy, John P; Hu, Jianying

2012-06-12

340

The Madagascar Bloom: A serendipitous study  

NASA Astrophysics Data System (ADS)

The late austral summer (February-April) phytoplankton bloom that occurs east of Madagascar exhibits significant interannual variability and at its largest extent covers ~1% of the world's ocean surface area. The bloom raises many intriguing questions about how it begins, is sustained, propagates to the east, exports carbon, and ends. It has been observed and studied using satellite ocean color observations, but the lack of in situ data makes it difficult to address these questions. Here we describe observations that were made serendipitously on a cruise in February 2005. These show clearly for the first time the simultaneous existence of a deep chlorophyll maximum at ~70-110 m depths (seen in SeaSoar fluorimeter data) and a surface chlorophyll signature [seen in Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite ocean color data]. The observations also show the modulation of the biological signature at the surface by the eddy field but not of the deep chlorophyll maximum. Trichodesmium dominates the bloom nearer to Madagascar, while the diatom Rhizosolenia clevei (and its symbiont Richelia intracellularis) dominates further from the island. The surface bloom seen in the SeaWiFS data is confined to the shallow (~30 m) mixed layer. It is hypothesized that the interannual variability in bloom intensity may be due to variations in coastal upwelling and thus the supply of iron, which is a micronutrient that can limit diazotroph growth.

Srokosz, M. A.; Quartly, G. D.

2013-01-01

341

The Madagascar Bloom - a serendipitous study  

NASA Astrophysics Data System (ADS)

The late austral summer (February-April) phytoplankton bloom that occurs east of Madagascar, exhibits significant interannual variability and at its largest extent covers ~1% of the world's ocean surface area. The bloom raises many intriguing questions about how it begins, is sustained, propagates to the east, exports carbon and ends. It has been observed and studied using satellite ocean colour observations, but the lack of in situ data makes it difficult to address these questions. Here we describe observations that were made on a cruise in February 2005 serendipitously. These show clearly for the first time the existence of both a deep chlorophyll maximum at ~70-110m depths (seen in SeaSoar fluorimeter data) and a surface chlorophyll signature (seen in SeaWiFS satellite ocean colour data). The observations also show the modulation of biological signature at the surface by the eddy field, but not apparently of the deep chlorophyll maximum. In situ observations indicate that Trichodesmium dominates the bloom nearer to Madagascar, while the diatom Rhizosolenia clevei (and its symbiont Richelia intracellularis) dominates further from the island. In addition, SeaSoar Optical Plankton Counter (OPC), temperature and salinity data suggest that the surface bloom seen in the SeaWiFS data is confined to the shallow (~30m) mixed layer. It is hypothesised that the interannual variability in bloom intensity may be due to variations in coastal upwelling and thus the supply of iron, which is a micronutrient that can limit diazotroph growth.

Srokosz, M. A.; Quartly, G.

2012-12-01

342

Case Study 1 Red Tide Detection in the Eastern Gulf of Mexico  

E-print Network

Case Study 1 Red Tide Detection in the Eastern Gulf of Mexico Using MODIS Imagery Chuanmin Hu1.1 Background Many of the red tides (i.e., harmful algal blooms or HABs) in the eastern Gulf of Mexico (GOM) (24 (Dierssen et al., 2006), they are commonly referred to as red tides. In the eastern GOM, red tides occur

Meyers, Steven D.

343

10 UC Santa Cruz Review / Fall 2008 asically," muses  

E-print Network

-tech than that, including under- water robots and remotely operated vehicles for deep ocean sampling has shifted her attention to the harmful algal blooms (HABs) that plague coastal waters, tracing how play more music (she is an accomplished pianist and a novice hammer dulcimer player) and pursue

Zhang, Yi

344

CYANOBACTERIA AND THEIR TOXINS.  

EPA Science Inventory

Science Questions Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

345

CYANOBACTERIA AND THEIR TOXINS  

EPA Science Inventory

Science Questions Harmful algal blooms (HAB) of cyanobacteria, also known as blue-green algae, have recently become more spatially and temporally prevalent in the US and worldwide. Cyanobacteria and their highly potent toxins are a significant hazard for human health and ...

346

Determining the influence of land-use on urea sources and transport within the Chesapeake Bay watershed  

Technology Transfer Automated Retrieval System (TEKTRAN)

Urea, a form of organic nitrogen found in fertilizers, manures and septic waste, has increasingly been discovered in surface waters throughout the Chesapeake Bay watershed and similar coastal systems. This nutrient is gaining recognition as a driver for the development of Harmful Algal Blooms (HABs)...

347

Ecosystem under Pressure: Examining the Phytoplankton Community in the High Ballast Water Discharge Environment of Galveston Bay, Texas (USA)  

E-print Network

Gradient Gel Electrophoresis DNA Deoxyribonucleic Acid EEZ Exclusive Economic Zone E/R Empty and Refill FIRe Fluorescence and Induction Relaxation FT Flow Through GB Galveston Bay GE Growout Experiment HAB Harmful Algal Bloom IMO International... analysis .............................................................................................. 17 2.2.2.1. Extraction of nucleic acids ...................................................................... 17 2.2.2.2. PCRamplification of 18S rDNA...

Steichen, Jamie L

2013-01-15

348

NOAA supported researchers are investigating how to predict and mitigate  

E-print Network

red tide event. Harmful Algal Blooms and Hypoxia in the Gulf of Mexico Introduction Dead fish of marine animals. The annual Gulf of Mexico hypoxic zone at the mouth of the Mississippi River is perhaps communities. The Problem The types and extent of HABs and their impacts has expanded in the Gulf of Mexico

349

Use of the FlowCAM for semi-automated recognition and enumeration of red tide cells ( Karenia brevis) in natural plankton samples  

Microsoft Academic Search

Early detection is the most effective way to mitigate the effects of harmful algal blooms (HAB). Cell counts based on examination of microplankton samples using settling chambers and visual inspection with an inverted microscope are tedious and time consuming, and counting precision is generally poor at low cell densities. The FlowCAM is a continuous imaging flow cytometer designed to characterize

Edward J. Buskey; Cammie J. Hyatt

2006-01-01

350

An overview of the marine food poisoning in Mexico  

Microsoft Academic Search

In the course of the last decade, huge events related to harmful algal blooms (HAB) have severely affected the environment in Mexico, even causing several human casualties. The tally of the toxins known up to date in Mexican waters includes: neurotoxin shellfish poisoning (NSP), paralytic shellfish poisoning (PSP), amnesic shellfish poisoning (ASP), tetrodotoxin (TTX) or puffer fish poisoning, ciguatera fish

A. P Sierra-Beltrán; A Cruz; E Núñez; L. M Del Villar; J Cerecero; J. L Ochoa

1998-01-01

351

Pleurochrysis pseudoroscoffensis (Prymnesiophyceae) blooms on the surface of the Salton Sea, California  

USGS Publications Warehouse

Dense populations of the coccolithophore Pleurochrysis pseudoroscoffensis were found in surface films at several locations around the Salton Sea in February-August, 1999. An unidentified coccolithophorid was also found in low densities in earlier studies of the lake (1955-1956). To our knowledge, this is the first record of this widespread marine species in any lake. Samples taken from surface films typically contained high densities of one or two other phytoplankton species as well as high densities of the coccolithophore. Presence or absence of specific algal pigments was used to validate direct cell counts. In a preliminary screen using a brine shrimp lethality assay, samples showed moderate activity. Extracts were then submitted to a mouse bioassay, and no toxic activity was observed. These results indicate that blooms of P. pseudoroscoffensis are probably not toxic to vertebrates and do not contribute to the various mortality events of birds and fish that occur in the Salton Sea.

Reifel, K.M.; McCoy, M.P.; Tiffany, M.A.; Rocke, T.E.; Trees, C.C.; Barlow, S.B.; Faulkner, D.J.; Hurlbert, S.H.

2001-01-01

352

Pleurochrysis pseudoroscoffensis (Prymnesiophyceae) blooms on the surface of the Salton Sea, California  

USGS Publications Warehouse

Dense populations of the coccolithophore Pleurochrysis pseudoroscoffensis were found in surface films at several locations around the Salton Sea in Februarya??August, 1999. An unidentified coccolithophorid was also found in low densities in earlier studies of the lake (1955a??1956). To our knowledge, this is the first record of this widespread marine species in any lake. Samples taken from surface films typically contained high densities of one or two other phytoplankton species as well as high densities of the coccolithophore. Presence or absence of specific algal pigments was used to validate direct cell counts. In a preliminary screen using a brine shrimp lethality assay, samples showed moderate activity. Extracts were then submitted to a mouse bioassay, and no toxic activity was observed. These results indicate that blooms of P. pseudoroscoffensis are probably not toxic to vertebrates and do not contribute to the various mortality events of birds and fish that occur in the Salton Sea.

Reifel, K.M.; McCoy, M.P.; Tiffany, M.A.; Rocke, T.E.; Trees, C.C.; Barlow, S.B.; Faulkner, D.J.; Hurlbert, S.H.

2001-01-01

353

Controlling cyanobacterial blooms by managing nutrient ratio and limitation in a large hyper-eutrophic lake: Lake Taihu, China.  

PubMed

Excessive nitrogen (N) and phosphorus (P) loading of aquatic ecosystems is a leading cause of eutrophication and harmful algal blooms worldwide, and reducing nutrient levels in water has been a primary management objective. To provide a rational protection strategy and predict future trends of eutrophication in eutrophic lakes, we need to understand the relationships between nutrient ratios and nutrient limitations. We conducted a set of outdoor bioassays at the shore of Lake Taihu. It showed that N only additions induced phytoplankton growth but adding only P did not. Combined N plus P additions promoted higher phytoplankton biomass than N only additions, which suggested that both N and P were deficient for maximum phytoplankton growth in this lake (TN:TP=18.9). When nutrients are present at less than 7.75-13.95mg/L TN and 0.41-0.74mg/L TP, the deficiency of either N or P or both limits the growth of phytoplankton. N limitation then takes place when the TN:TP ratio is less than 21.5-24.7 (TDN:TDP was 34.2-44.3), and P limitation occurs above this. Therefore, according to this ratio, controlling N when N limitation exists and controlling P when P deficiency is present will prevent algal blooms effectively in the short term. But for the long term, a persistent dual nutrient (N and P) management strategy is necessary. PMID:25597665

Ma, Jianrong; Qin, Boqiang; Wu, Pan; Zhou, Jian; Niu, Cheng; Deng, Jianming; Niu, Hailin

2015-01-01

354

Evaluation of photo-reactive siderophore producing bacteria before, during and after a bloom of the dinoflagellate Lingulodinium polyedrum.  

PubMed

Evidence is increasing for a mutualistic relationship between phytoplankton and heterotrophic marine bacteria. It has been proposed that bacteria producing photoactive iron binding compounds known as siderophores could play an important role in such mutualistic associations by producing bioavailable iron utilizable by phytoplankton and in exchange receive autotrophically derived DOM. In order to understand the potential role photoactive siderophores might be playing in bacterial-algal mutualism or marine biogeochemistry in general, it is important to be able to detect and quantify their presence in various environments. One approach to accomplish that end is to make use of high sensitivity genomics technology (qPCR) to search for siderophore biosynthesis genes related to the production of photoactive siderophores. In this way one can access their "biochemical potential" and utilize this information as a proxy for the presence of these siderophores in the marine environment. In this report we studied the correlation of the presence of bacteria producing one of the three photoactive siderophores relative to total bacterial and dinoflagellate numbers from surface water at the Scripps Pier before, during, and after fall bloom of the dinoflagellate Lingulodinium polyedrum. We believe that these findings will aid us in gauging the importance of photoactive siderophores in the marine environment and in harmful algal bloom dynamics in particular. PMID:24760287

Yarimizu, Kyoko; Polido, Geraldine; Gärdes, Astrid; Carter, Melissa L; Hilbern, Mary; Carrano, Carl J

2014-06-01

355

ALGAE BLOOMS AND PHOSPHORUS LOADING IN LAKE LOWELL, IDAHO  

EPA Science Inventory

Algae blooms limit recreational use of Lake Lowell, ID (17050114) by reducing water clarity and esthetic qualities. Under bloom conditions, algae have a negative impact on the reservoir fishery because of periodic oxygen depletion associated with respiration and decomposition. ...

356

ExoHab Pilot Project & Field Tests for Moon-Mars Human Laboratories  

NASA Astrophysics Data System (ADS)

We studied concepts for a minimal Moon-Mars habitat, in focussing on the system aspects and coordinating every different part as part an evolving architecture. We validated experimentally the Habitat and Laboratory ExoHab concept constraints during EuroGeoMars campaign in Utah desert research station (from 24 Jan. to 28 Feb. 2009) and EuroMoonMars/DOMMEX campaigns in Nov 2009 and February-April 2010. We discuss from the ILEWG ExoHab concept studies and field simulations the specifics of human exploration, with focus on habitability and human performance. In the ExoHab pilot concept project (supported by ILEWG, ESA NASA), we justify the case for a scientific and exploration outpost allowing experiments, sample analysis in laboratory (relevant to the origin and evolution of planets and life, geophysical and geo-chemical studies, astrobiology and life sciences, observation sciences, technology demonstration, resource utilisation, human exploration and settlement). In this modular concept, we consider various infra structure elements: core habitat, Extra Vehicular activity (EVA), crew mobility, energy supply, recycling module, communication, green house and food production, operations. We review some studies space agencies' architecture proposals, with landers, orbiters, rovers, habitats, surface operations and protocols. We focus on the easiest and the soonest way in settling a minimal base immediately operational in scientific experimentation and exploration, but not immediately autonomous. Through a modular concept, this outpost will be possibly evolved into a long duration or permanent base. We will analyse the possibilities of settling such a minimal base by means of the current and near term propulsion technology, as a full Ariane 5 ME carrying 1.7 T of gross payload to the surface of the Moon (Integrated Exploration Study, ESA ESTEC [1,2]). The low solar rays incidence may permit having ice in deep craters, which will be beneficial for the evolution of the outpost into an autonomous base. After a robotic sample return mission, a human presence will allow deeper research through well chosen geological samples. A polar lunar outpost can serve to prepare for a Mars outpost: system and crew safety aspects, use of local resources, operations on farside with limited communication to Earth, planetary protection protocol, astrobiology and life sciences. References: [1] Exploration Architecture Trade Report", ESA 2008. [2] Integrated Exploration Architecture", ESA, 2008. [3] 9th ILEWG International Conference on Exploration Utilization of the moon, 2007, sci.esa.int/ilewg [4] Schrunk et al , The Moon: Resources, Future Development and Colonization", 1999. [5] The Moon as a Platform for Astronomy and Space Science", B.H. Foing, ASR 14 (6), 1994. [6] Boche-Sauvan L., Foing B (2008) MSc/ESTEC report. Co-authors, ILEWG ExoGeoLab & ExoHab Team: B.H. Foing(1,11)*#, C. Stoker(2,11)*, P. Ehrenfreund(10,11), L. Boche-Sauvan(1,11)*, L. Wendt(8)*, C. Gross(8, 11)*, C. Thiel(9)*, S. Peters(1,6)*, A. Borst(1,6)*, J. Zavaleta(2)*, P. Sarrazin(2)*, D. Blake(2), J. Page(1,4,11), V. Pletser(5,11)*, E. Monaghan(1)*, P. Mahapatra(1)#, A. Noroozi(3), P. Giannopoulos(1,11) , A. Calzada(1,6,11), R. Walker(7), T. Zegers(1, 15) #, G. Groemer(12)# , W. Stumptner(12)#, B. Foing(2,5), J. K. Blom(3)#, A. Perrin(14)#, M. Mikolajczak(14)#, S. Chevrier(14)#, S. Direito(6)#, S. Voute (18)#, A. Olmedo-Soler(17)#, T. E. Zegers(1, 18)#, D. Scheer(12)#, K. Bickert(12)#, D. Schildhammer(12)#, B. Jantscher(1, 11, 12)#, MECA Team(6)#, ExoGeoLab ILEWG ExoHab teams(1,4,11) EuroGeoMars team(1,4,5); 1)ESTEC/SRE-S Postbus 299, 2200 AG Noordwijk, NL, 2)NASA Ames , 3)Delft TU , 4)ESTEC TEC Technology Dir., 5)ESTEC HSF Human Spaceflight, 6)VU Amsterdam, 7)ESTEC Education Office, 8)FU Berlin, 9)Max Planck Goettingen, 10)Leiden/GWU , 11)ILEWG ExoHab Team, 12)Austrian Space Forum (OEWF Innsbruck); 14) Ecole de l'Air, Salons de Provence, 15) Utrecht U., 16) MECA Team, 17) Olmedo Knowledge Systems S.L.; * EuroGeoMars Utah crew , # ILEWG Eifel crew, EuroM

Foing, Bernard

2010-05-01

357

Platy algal banks: Modern and ancient  

SciTech Connect

Plaly algal banks and associated cycles in the lower Ismay zone of the Paradox Formation are exposed along the walls of the San Juan River canyon, southeastern Utah. These complexes closely resemble algal bank reservoirs in the lower Ismay zone of Ismay and Cache, and possibly other Paradox basin fields. Similarities include facies relationships, lateral and vertical textural variations, and early diagenesis. Extensive algal banks exposed along the San Juan canyon generally have flat bases and mound and swale topographic surfaces, and are separated by interbank channels. The surficial mounds have a regular amplitude and wavelength suggesting a hydrologic rather than biologic influence on topography. The banks themselves, however, are believed to be thick, predominantly in-situ accumulations of platy algae. Distribution of algal banks can be mapped on a field scale; mound and swale topographic features may be identified in core on the basis of depositional and early diagenetic characteristics. Halimeda bioherms (Holocene) cover large areas behind the Great Barrier Reef, developing adjacent to the deep passes that separate the individual reefs. These large in-situ accumulations (20-50 m deep) display similar bank geometries, interbank features, topographic features, vertical textural sequence (including porosity type and distribution), and facies relationships to algal banks observed in the outcropping and subsurface Paradox Formation. Although the hydrodynamic and paleobathymetric settings differ markedly between these two examples, analogies between the mounds themselves are very close. The resemblance lends relevance to exploration and development drilling.

Brinton, L. (Marathon Oil Co., Littleton, CO (USA))

1990-05-01

358

3. GENERAL VIEW OF REMAINS OF 40" BLOOMING MILL; THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. GENERAL VIEW OF REMAINS OF 40" BLOOMING MILL; THE ENGINE ROOM CONTAINING THE MESTA-CORLISS STEAM ENGINE, IS LOCATED AT THE FAR END OF THE MILL AS SEEN TO THE FAR RIGHT (THE BUILDING WITH THE SHED ROOF). - Republic Iron & Steel Company, Youngstown Works, Blooming Mill & Blooming Mill Engines, North of Poland Avenue, Youngstown, Mahoning County, OH

359

Bennett, Bloom and Boyer: Toward a Critical Discussion.  

ERIC Educational Resources Information Center

An overview is provided of the educational philosophies of Allan Bloom, Lynne V. Cheney, William Bennett, and Ernest Boyer, with special focus on their political underpinnings. The essay begins with an examination of the issues discussed in "The Closing of the American Mind," by Allan Bloom. Concern and disagreement is expressed about: (1) Bloom's…

Reitz, Charles

360

Access-Efficient Balanced Bloom Filters Yossi Kanizo  

E-print Network

in an off-chip setting (that is, requiring accessing 21 memory blocks per element) or distributed over and Bloom Filters hash elements into several arbitrary memory blocks, Bloom Filters actually need high memory-access rates. On the other hand, hashing all Bloom Filter elements into a single memory block

Keslassy, Isaac

361

Drivers and Food Web Effects of Gonyostomum semen Blooms  

E-print Network

in a decreased coupling between phytoplankton and higher trophic levels during blooms. The studies included period. Temperature and length of the growing season affected the occurrence and, to a lesser extent, bloom formation of G. semen, but local factors such as pH and water colour were more important for bloom

362

Combination of uniform design with artificial neural network coupling genetic algorithm: an effective way to obtain high yield of biomass and algicidal compound of a novel HABs control actinomycete  

PubMed Central

Controlling harmful algae blooms (HABs) using microbial algicides is cheap, efficient and environmental-friendly. However, obtaining high yield of algicidal microbes to meet the need of field test is still a big challenge since qualitative and quantitative analysis of algicidal compounds is difficult. In this study, we developed a protocol to increase the yield of both biomass and algicidal compound present in a novel algicidal actinomycete Streptomyces alboflavus RPS, which kills Phaeocystis globosa. To overcome the problem in algicidal compound quantification, we chose algicidal ratio as the index and used artificial neural network to fit the data, which was appropriate for this nonlinear situation. In this protocol, we firstly determined five main influencing factors through single factor experiments and generated the multifactorial experimental groups with a U15(155) uniform-design-table. Then, we used the traditional quadratic polynomial stepwise regression model and an accurate, fully optimized BP-neural network to simulate the fermentation. Optimized with genetic algorithm and verified using experiments, we successfully increased the algicidal ratio of the fermentation broth by 16.90% and the dry mycelial weight by 69.27%. These results suggested that this newly developed approach is a viable and easy way to optimize the fermentation conditions for algicidal microorganisms. PMID:24886410

2014-01-01

363

Integrating phylogeny, geographic niche partitioning and secondary metabolite synthesis in bloom-forming Planktothrix.  

PubMed

Toxic freshwater cyanobacteria form harmful algal blooms that can cause acute toxicity to humans and livestock. Globally distributed, bloom-forming cyanobacteria Planktothrix either retain or lose the mcy gene cluster (encoding the synthesis of the secondary metabolite hepatotoxin microcystin or MC), resulting in a variable spatial/temporal distribution of (non)toxic genotypes. Despite their importance to human well-being, such genotype diversity is not being mapped at scales relevant to nature. We aimed to reveal the factors influencing the dispersal of those genotypes by analyzing 138 strains (from Europe, Russia, North America and East Africa) for their (i) mcy gene cluster composition, (ii) phylogeny and adaptation to their habitat and (iii) ribosomally and nonribosomally synthesized oligopeptide products. Although all the strains from different species contained at least remnants of the mcy gene cluster, various phylogenetic lineages evolved and adapted to rather specific ecological niches (for example, through pigmentation and gas vesicle protein size). No evidence for an increased abundance of specific peptides in the absence of MC was found. MC and peptide distribution rather depended on phylogeny, ecophysiological adaptation and geographic distance. Together, these findings provide evidence that MC and peptide production are primarily related to speciation processes, while within a phylogenetic lineage the probability that strains differ in peptide composition increases with geographic distance. PMID:25325384

Kurmayer, Rainer; Blom, Judith F; Deng, Li; Pernthaler, Jakob

2014-10-17

364

A cold phase of the East Pacific triggers new phytoplankton blooms in San Francisco Bay  

PubMed Central

Ecological observations sustained over decades often reveal abrupt changes in biological communities that signal altered ecosystem states. We report a large shift in the biological communities of San Francisco Bay, first detected as increasing phytoplankton biomass and occurrences of new seasonal blooms that began in 1999. This phytoplankton increase is paradoxical because it occurred in an era of decreasing wastewater nutrient inputs and reduced nitrogen and phosphorus concentrations, contrary to the guiding paradigm that algal biomass in estuaries increases in proportion to nutrient inputs from their watersheds. Coincidental changes included sharp declines in the abundance of bivalve mollusks, the key phytoplankton consumers in this estuary, and record high abundances of several bivalve predators: Bay shrimp, English sole, and Dungeness crab. The phytoplankton increase is consistent with a trophic cascade resulting from heightened predation on bivalves and suppression of their filtration control on phytoplankton growth. These community changes in San Francisco Bay across three trophic levels followed a state change in the California Current System characterized by increased upwelling intensity, amplified primary production, and strengthened southerly flows. These diagnostic features of the East Pacific “cold phase” lead to strong recruitment and immigration of juvenile flatfish and crustaceans into estuaries where they feed and develop. This study, built from three decades of observation, reveals a previously unrecognized mechanism of ocean–estuary connectivity. Interdecadal oceanic regime changes can propagate into estuaries, altering their community structure and efficiency of transforming land-derived nutrients into algal biomass. PMID:18000053

Cloern, James E.; Jassby, Alan D.; Thompson, Janet K.; Hieb, Kathryn A.

2007-01-01

365

A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization.  

PubMed

Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the 'iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction. PMID:11048709

Boyd, P W; Watson, A J; Law, C S; Abraham, E R; Trull, T; Murdoch, R; Bakker, D C; Bowie, A R; Buesseler, K O; Chang, H; Charette, M; Croot, P; Downing, K; Frew, R; Gall, M; Hadfield, M; Hall, J; Harvey, M; Jameson, G; LaRoche, J; Liddicoat, M; Ling, R; Maldonado, M T; McKay, R M; Nodder, S; Pickmere, S; Pridmore, R; Rintoul, S; Safi, K; Sutton, P; Strzepek, R; Tanneberger, K; Turner, S; Waite, A; Zeldis, J

2000-10-12

366

Harmful cyanobacterial blooms: causes, consequences, and controls.  

PubMed

Cyanobacteria are the Earth's oldest oxygenic photoautotrophs and have had major impacts on shaping its biosphere. Their long evolutionary history (? 3.5 by) has enabled them to adapt to geochemical and climatic changes, and more recently anthropogenic modifications of aquatic environments, including nutrient over-enrichment (eutrophication), water diversions, withdrawals, and salinization. Many cyanobacterial genera exhibit optimal growth rates and bloom potentials at relatively high water temperatures; hence global warming plays a key role in their expansion and persistence. Bloom-forming cyanobacterial taxa can be harmful from environmental, organismal, and human health perspectives by outcompeting beneficial phytoplankton, depleting oxygen upon bloom senescence, and producing a variety of toxic secondary metabolites (e.g., cyanotoxins). How environmental factors impact cyanotoxin production is the subject of ongoing research, but nutrient (N, P and trace metals) supply rates, light, temperature, oxidative stressors, interactions with other biota (bacteria, viruses and animal grazers), and most likely, the combined effects of these factors are all involved. Accordingly, strategies aimed at controlling and mitigating harmful blooms have focused on manipulating these dynamic factors. The applicability and feasibility of various controls and management approaches is discussed for natural waters and drinking water supplies. Strategies based on physical, chemical, and biological manipulations of specific factors show promise; however, a key underlying approach that should be considered in almost all instances is nutrient (both N and P) input reductions; which have been shown to effectively reduce cyanobacterial biomass, and therefore limit health risks and frequencies of hypoxic events. PMID:23314096

Paerl, Hans W; Otten, Timothy G

2013-05-01

367

HIERARCHICAL DOCUMENT CATEGORIZATION USING ASSOCIATIVE Niels Bloom  

E-print Network

. The system should also be able to deal with adding, removing and editing documents. In earlier work [1], we- work can be used to find connections between documents by taking one document as input, spreadingHIERARCHICAL DOCUMENT CATEGORIZATION USING ASSOCIATIVE NETWORKS Niels Bloom Perrit B.V. Hengelo

Vellekoop, Michel

368

JELLYFISH BLOOMS The growth of jellyfishes  

E-print Network

JELLYFISH BLOOMS The growth of jellyfishes M. L. D. Palomares Ã? D. Pauly Published online: 15 and methods have been used to study the growth of jellyfish, with the result that few generalities have that this situation can be overcome by length-frequency analysis (LFA), applied to jellyfish bell diameter (i

Pauly, Daniel

369

Factors initiating phytoplankton blooms and resulting effects on dissolved oxygen in Duwamish River estuary, Seattle, Washington  

USGS Publications Warehouse

Phytoplankton productivity, standing stock, and related environmental factors were studied during 1964-66 in the Duwamish River estuary, at Seattle, Wash., to ascertain the factors that affect phytoplankton growth in the estuary; a knowledge of these factors in turn permits the detection and evaluation of the influence that effluent nutrients have on phytoplankton production. The factors that control the concentration of dissolved oxygen were also evaluated because of the importance of dissolved oxygen to the salmonid populations that migrate through the estuary. Phytoplankton blooms, primarily of diatoms, occurred in the lower estuary during August 1965 and 1966. No bloom occurred during 1964, but the presence of oxygen-supersaturated surface water in August 1963 indicates that a bloom did occur then. Nutrients probably were not the primary factor controlling the timing of phytoplankton blooms. Ammonia ,and phosphate concentrations increased significantly downstream from the Municipality of Metropolitan Seattle's Renton Treatment Plant outfall after the plant began operation in June 1965, and concentrations of nitrogen and phosphorus were relatively high before operation of the Renton Treatment Plant and during nonbloom periods. The consistent coincidence of blooms with minimum fresh-water discharge and tidal exchange during August throughout the study period indicates that bloom timing probably was controlled mostly by hydrographic factors that determine retention time and stability of the surface-water layer. This control was demonstrated in part by a highly significant correlation of gross productivity with retention time (as indicated by fresh-water discharge) and vertical stability (as indicated by the difference between mean surface and mean bottom temperatures). The failure of a bloom to develop in 1964 is related to a minimum fresh-water discharge that was much greater than normal during that summer. Hydrographic factors are apparently important because, as shown by studies of other estuarine environments by other workers, phytoplankton production increases when the zone of vertical turbulent mixing is not markedly deeper than the compensation depth. Phytoplankton cells produced in the surface waters sink, thereby contributing oxidizable organic matter to the bottom saline-water wedge. The maximum BOD (biochemical oxygen demand) in this bottom wedge occurs in the same section of the estuary and ,at the same time as the maximum phytoplankton biomass (as indicated by chlorophyll a) and minimum DO (dissolved oxygen). Other sources of BOD occur in the estuary, and conditions of minimum discharge and tidal exchange assist in reducing DO. Nonetheless, the highly significant correlation of chlorophyll a with BOD throughout the summer indicates that respiration and decomposition of phytoplankton cells is dearly an important contributor of BOD. Increases in the biomass and resultant B0D of blooms because of increased effluent nutrients presumably would further decrease the concentration of DO. This possible effect of effluent nutrients was evaluated by laboratory .bioassays and by a comparison of mean annual biomasses in the estuary. A green algal population in vitro did increase in response to added effluent nutrients; however, the available field data suggest that a 46-percent increase in effluent discharge between 1965 and 1966 did not increase the estuary's phytoplankton biomass significantly.

Welch, Eugene Brummer

1969-01-01

370

Phytoplankton bloom dynamics in coastal ecosystems: A review with some general lessons from sustained investigation of San Francisco Bay, California  

NASA Astrophysics Data System (ADS)

Phytoplankton blooms are prominent features of biological variability in shallow coastal ecosystems such as estuaries, lagoons, bays, and tidal rivers. Long-term observation and research in San Francisco Bay illustrates some patterns of phytoplankton spatial and temporal variability and the underlying mechanisms of this variability. Blooms are events of rapid production and accumulation of phytoplankton biomass that are usually responses to changing physical forcings originating in the coastal ocean (e.g., tides), the atmosphere (wind), or on the land surface (precipitation and river runoff). These physical forcings have different timescales of variability, so algal blooms can be short-term episodic events, recurrent seasonal phenomena, or rare events associated with exceptional climatic or hydrologic conditions. The biogeochemical role of phytoplankton primary production is to transform and incorporate reactive inorganic elements into organic forms, and these transformations are rapid and lead to measurable geochemical change during blooms. Examples include the depletion of inorganic nutrients (N, P, Si), supersaturation of oxygen and removal of carbon dioxide, shifts in the isotopic composition of reactive elements (C, N), production of climatically active trace gases (methyl bromide, dimethylsulfide), changes in the chemical form and toxicity of trace metals (As, Cd, Ni, Zn), changes in the biochemical composition and reactivity of the suspended particulate matter, and synthesis of organic matter required for the reproduction and growth of heterotrophs, including bacteria, zooplankton, and benthic consumer animals. Some classes of phytoplankton play special roles in the cycling of elements or synthesis of specific organic molecules, but we have only rudimentary understanding of the forces that select for and promote blooms of these species. Mounting evidence suggests that the natural cycles of bloom variability are being altered on a global scale by human activities including the input of toxic contaminants and nutrients, manipulation of river flows, and translocation of species. This hypothesis will be a key component of our effort to understand global change at the land-sea interface. Pursuit of this hypothesis will require creative approaches for distinguishing natural and anthropogenic sources of phytoplankton population variability, as well as recognition that the modes of human disturbance of coastal bloom cycles operate interactively and cannot be studied as isolated processes.

Cloern, James E.

1996-05-01

371

A catchment-scale palaeolimnological investigation into multiple forcings of algal community change  

NASA Astrophysics Data System (ADS)

A catchment-scale palaeolimnological investigation of sedimentary algal pigments spanning the past ~200 years was undertaken on lakes which drain into Windermere, England's largest and longest lake. We aimed to determine the relative influence of past regional (climatic, atmospheric deposition) and local (land-use, hydrological modification, point-source pollution) drivers of algal community change by comparing three fertile lowland lakes (Blelham Tarn, Esthwaite Water and Rydal Water) and two upland tarns (Stickle and Easedale Tarns) to better inform a catchment-wide management strategy for Windermere. Drivers of change at the upland sites included atmospheric acid deposition, climatic change and structural modifications caused by dam installation, whereas the influence of agriculture and point-source pollution is greater in the lakes in the lowland parts of the catchment. As a result, contrasting algal responses were noted in the lakes. For example, the cyanobacterial pigment zeaxanthin and the cryptophte pigment alloxanthin increased at Stickle Tarn (359% and 321% respectively) corresponding with the establishment of a dam at the outflow of the tarn in 1838. However, post-1900's the concentration of these pigments declined both at Stickle and at Easedale Tarn coincident with increased storm events and in the later decades of the century (~1980s onwards) decreases in acid deposition. In the lowland sites the cyanobacterial pigment aphanizophyll increased by 400-7000% and the indicator of total algal production ?-carotene increased as much as six-fold indicating a substantial degradation in water quality and the onset of cyanobacterial blooms since the 1950's. In the lowland sites, degradation of water quality was closely linked to sewage installations and treatment work upgrades during the 1950's-70's and intensification of agricultural practices most notably increases in sheep stocking densities, which expanded in the 1950's. In lowland lakes with a higher catchment: lake area ratio, climate (specifically precipitation) had a more demonstrable impact on algal communities, through enhanced delivery of catchment nutrients. Therefore, we have identified water-bodies likely to be most 'at-risk' from future climate change, in order to advise on tailored management strategies for individual lakes within the catchment.

Moorhouse, H. L.; McGowan, S.; Jones, M.; Brayshaw, S.; Barker, P.; Leavitt, P.

2013-12-01

372

Damage Tolerance Testing of a NASA TransHab Derivative Woven Inflatable Module  

NASA Technical Reports Server (NTRS)

Current options for Lunar habitat architecture include inflatable habitats and airlocks. Inflatable structures can have mass and volume advantages over conventional structures. Inflatable structures are perceived to carry additional risk because they are at a lower Technical Readiness Level (TRL) than conventional metallic structures. One of the risks associated with inflatable structures is understanding the tolerance to component damage and the resulting behavior of the system after the damage is introduced. The Damage Tolerance Test (DTT) is designed to study the structural integrity of an expandable structure during and subsequent to induced damage. The TransHab Project developed an experimental inflatable module developed at Johnson Space Center in the 1990's. The TransHab design was originally envisioned for use in Mars Transits but was also studied as a potential habitat for the International Space Station (ISS). The design of the TransHab module was based on a woven design using an Aramid fabric. Testing of this design demonstrated a high level of predictability and repeatability and good correlation with analytical predictions of stresses and deflections. Based on JSC's experience with the design and analysis of woven inflatable structures, the Damage Tolerance Test article was designed and fabricated using a woven design. The Damage Tolerance Test Article consists of a load bearing restraint layer, a bladder or gas barrier, and a structural metallic core. The test article restraint layer is fabricated from one inch wide Kevlar webbing that is woven in a basket weave pattern. Underneath the structural restraint layer is the bladder or gas barrier. For this test the bladder was required to maintain pressure for testing only and was not representative of a flight design. The bladder and structural restraint layer attach to the structural core of the module at steel bulkheads at each end. The two bulkheads are separated by a 10 foot center tube which provides the structural support for the module when in a non-inflated state as well as resists a portion of the axial load when pressurized. The longitudinal members of the structural restraint layer are attached to the bulkheads using a series of clevises that are bolted to the bulkheads. Strain gages are placed on the clevises that can measure change in load when the structural restraint is inflated. The test module is 88 inches in diameter and 120 inches in height. The objectives of the DTT are to (1) verify the structural integrity of the assembled and pressurized structure when a section of the structural restraint layer is cut by a foreign object, and (2) verify the load distribution of the structural restraint layer during pressurization, before and after the structural restraint layer is severed. For this test, a longitudinal structural restraint strap will be severed using a linear shape charge. The linear shape charge was designed specifically for this application to cut only a single longitudinal strap, while not damaging the bladder. An array of strain gages were located at the bulkhead mounted clevises where the longitudinal restraint layer straps are attached. The DTT article was inflated to 45 psig, 25% of the ultimate design pressure, and one of the one-inch wide longitudinal structural members was severed. Strain gage measurements of loading in an array of longitudinal straps were taken throughout pressurization of the module to 45 psig, before firing of the linear shape charge, and after firing of the shape charge and separation of the strap. During testing not only were the original objectives met but better than expected results occurred. This paper will discuss space inflatable structures, damage tolerance analysis, test results, and applicability to the Lunar architecture.

Edgecombe, John; delaFuente, Horacio; Valle, Gerald D.

2008-01-01

373

Comparison of graphite, aluminum, and TransHab shielding material characteristics in a high-energy neutron field  

NASA Technical Reports Server (NTRS)

Space radiation transport models clearly show that low atomic weight materials provide a better shielding protection for interplanetary human missions than high atomic weight materials. These model studies have concentrated on shielding properties against charged particles. A light-weight, inflatable habitat module called TransHab was built and shown to provide adequate protection against micrometeoroid impacts and good shielding properties against charged particle radiation in the International Space Station orbits. An experiment using a tissue equivalent proportional counter, to study the changes in dose and lineal energy spectra with graphite, aluminum, and a TransHab build-up as shielding, was carried out at the Los Alamos Nuclear Science Center neutron facility. It is a continuation of a previous study using regolith and doped polyethylene materials. This paper describes the results and their comparison with the previous study. Published by Elsevier Science Ltd.

Badhwar, G. D.; Huff, H.; Wilkins, R.; Thibeault, Sheila

2002-01-01

374

Algal Toxins Alter Copepod Feeding Behavior  

Microsoft Academic Search

Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of

Jiarong Hong; Siddharth Talapatra; Joseph Katz; Patricia A. Tester; Rebecca J. Waggett

2012-01-01

375

FIRST LAW ANALYSIS OF AN ALGAL ORGANISM  

Technology Transfer Automated Retrieval System (TEKTRAN)

Photosynthesis requires energy from electromagnetic radiation in the visible light range. The incident energy on an algal organism must fall on the antenna structures of the organism that harvest the electromagnetic radiation for the photosynthetic active reaction centers. Ideally, the antenna would...

376

Resolving Mixed Algal Species in Hyperspectral Images  

PubMed Central

We investigated a lab-based hyperspectral imaging system's response from pure (single) and mixed (two) algal cultures containing known algae types and volumetric combinations to characterize the system's performance. The spectral response to volumetric changes in single and combinations of algal mixtures with known ratios were tested. Constrained linear spectral unmixing was applied to extract the algal content of the mixtures based on abundances that produced the lowest root mean square error. Percent prediction error was computed as the difference between actual percent volumetric content and abundances at minimum RMS error. Best prediction errors were computed as 0.4%, 0.4% and 6.3% for the mixed spectra from three independent experiments. The worst prediction errors were found as 5.6%, 5.4% and 13.4% for the same order of experiments. Additionally, Beer-Lambert's law was utilized to relate transmittance to different volumes of pure algal suspensions demonstrating linear logarithmic trends for optical property measurements. PMID:24451451

Mehrubeoglu, Mehrube; Teng, Ming Y.; Zimba, Paul V.

2014-01-01

377

Algal Toxins Alter Copepod Feeding Behavior  

PubMed Central

Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepod’s feeding appendages–a “sampling beating” that has short durations (<100 ms) and involves little fluid entrainment and a longer duration “grazing beating” that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepod’s grazing behavior. These findings add critical insight into how these algal toxins may influence the copepod’s feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods. PMID:22629336

Hong, Jiarong; Talapatra, Siddharth; Katz, Joseph; Tester, Patricia A.; Waggett, Rebecca J.; Place, Allen R.

2012-01-01

378

Algal toxins alter copepod feeding behavior.  

PubMed

Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepod's feeding appendages-a "sampling beating" that has short durations (<100 ms) and involves little fluid entrainment and a longer duration "grazing beating" that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepod's grazing behavior. These findings add critical insight into how these algal toxins may influence the copepod's feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods. PMID:22629336

Hong, Jiarong; Talapatra, Siddharth; Katz, Joseph; Tester, Patricia A; Waggett, Rebecca J; Place, Allen R

2012-01-01

379

Modeling of overlap thermal blooming in smoke  

NASA Astrophysics Data System (ADS)

The systems level codes used to model high energy laser (HEL) propagation for potential military applications do not account for losses of laser energy due to droplet evaporation. As a consequence, these evaporative effects represent a net reduction in the amount of overlap thermal blooming. An algorithm we developed to fill this void and its implementation into the U.S. Army's systems level propagation code, BRLPRO, will be discussed. Our approach modifies the phase integral computations of BRLPRO to include the effects on N phosphoric smoke clouds along the propagation path. The key component of this algorithm is the FRACTION model which determines the fraction of the smoke aerosol absorption within a smoke cloud which is effective in heating the atmosphere and causing thermal blooming. FRACTION methodology provides a first-principle calculation of the time-averaged thermodynamics which describe the vaporization resulting from the interaction of laser radiation with hygroscopic smoke particles.

Oconnor, R. E.; Harper, R. C.; Reynolds, R. W.

1983-07-01

380

Perturbation growth by thermal blooming in turbulence  

SciTech Connect

The stability of a phase-compensated laser beam propagating in a turbulent absorbing fluid is considered. Small-scale transverse optical perturbations from turbulence and noise grow in thermal blooming by two instabilities: the uncompensated stimulated thermal Rayleigh scattering instability, and the closed-loop instability. Linearized perturbation theory is used to calculate the electric field spectrum as a Taylor series in time and as superposition of stable and unstable modes. The method is applicable to fluids with arbitrary parameter variations along the path. Compensated perturbations grow exponentially, and uncompensated ones grow quasi-exponentially. The instability growth is in good agreement with numerical simulations of full nonlinear thermal blooming. If the growth rate exceeds the damping rate from other phenomena then the perturbations grow until limited by nonlinear saturation, at which point the beam is significantly degraded. At saturation the laser beam spontaneously breaks into small-scale transverse structures such as filaments or ribbons. 18 refs., 2 figs.

Karr, T.J.; Morris, J.R.; Chambers, D.H.; Viecelli, J.A.; Cramer, P.G.

1989-01-04

381

New Coccolithophore Bloom in Bering Sea  

NASA Technical Reports Server (NTRS)

For the fourth year in a row it appears as if there is a bloom of coccolithophores-marine single-celled plants with calcite scales-in the Bering Sea off the coast of Alaska. Similar blooms were rare before 1997, but they have appeared every year since then. Scientists believe the coccolithophore blooms are the result of changing wind patterns in the region. Weaker than normal winds fail to mix the water of the Bering Sea, resulting in the growth of coccolithophores instead of other types of phytoplankton. Seabird populations have also been changing as a result of this climate change. The Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, saw the coccolith-brightened waters of the Bering Sea in 1997, 1998, and 1999. The waters have looked fairly bright again this winter and spring, as seen in this SeaWiFS image acquired April 29, 2000. But scientists are unsure whether this year's phenomenon is caused by living coccolithophorids, re-suspended coccoliths, or something else. Like all phytoplankton, coccolithophores contain chlorophyll and have the tendency to multiply rapidly near the surface. Yet, in large numbers, coccolithophores periodically shed their tiny scales, called 'coccoliths,' by the bucketful into the surrounding waters. The calcium-rich coccoliths turn the normally dark water a bright, milky aquamarine, making coccolithophore blooms easy to spot in satellite imagery. The edge of the whitish cloud in the water seen in this image is roughly 50 kilometers off the West Coast of Alaska. For more information see: SeaWiFS home page Changing Currents Color the Bering Sea a New Shade of Blue Image courtesy SeaWiFS project

2002-01-01

382

Niches of two polysaccharide-degrading Polaribacter isolates from the North Sea during a spring diatom bloom.  

PubMed

Members of the flavobacterial genus Polaribacter thrive in response to North Sea spring phytoplankton blooms. We analyzed two respective Polaribacter species by whole genome sequencing, comparative genomics, substrate tests and proteomics. Both can degrade algal polysaccharides but occupy distinct niches. The liquid culture isolate Polaribacter sp. strain Hel1_33_49 has a 3.0-Mbp genome with an overall peptidase:CAZyme ratio of 1.37, four putative polysaccharide utilization loci (PULs) and features proteorhodopsin, whereas the agar plate isolate Polaribacter sp. strain Hel1_85 has a 3.9-Mbp genome with an even peptidase:CAZyme ratio, eight PULs, a mannitol dehydrogenase for decomposing algal mannitol-capped polysaccharides but no proteorhodopsin. Unlike other sequenced Polaribacter species, both isolates have larger sulfatase-rich PULs, supporting earlier assumptions that Polaribacter take part in the decomposition of sulfated polysaccharides. Both strains grow on algal laminarin and the sulfated polysaccharide chondroitin sulfate. For strain Hel1_33_49, we identified by proteomics (i) a laminarin-induced PUL, (ii) chondroitin sulfate-induced CAZymes and (iii) a chondroitin-induced operon that likely enables chondroitin sulfate recognition. These and other data suggest that strain Hel1_33_49 is a planktonic flavobacterium feeding on proteins and a small subset of algal polysaccharides, while the more versatile strain Hel1_85 can decompose a broader spectrum of polysaccharides and likely associates with algae.The ISME Journal advance online publication, 5 December 2014; doi:10.1038/ismej.2014.225. PMID:25478683

Xing, Peng; Hahnke, Richard L; Unfried, Frank; Markert, Stephanie; Huang, Sixing; Barbeyron, Tristan; Harder, Jens; Becher, Dörte; Schweder, Thomas; Glöckner, Frank Oliver; Amann, Rudolf I; Teeling, Hanno

2014-12-01

383

Perturbation growth by thermal blooming in turbulence  

SciTech Connect

The stability of a phase-compensated laser beam propagating in a turbulent absorbing fluid is considered. Small-scale transverse optical perturbations caused by turbulence and noise grow in thermal blooming by two instabilities: the uncompensated stimulated thermal Rayleigh scattering instability and the closed-loop instability. Linearized perturbation theory is used to calculate the electric field spectrum as a Taylor series in time and as a superposition of stable and unstable modes. The method is applicable to fluids with arbitrary parameter variations along the path. Compensated perturbations grow exponentially, and uncompensated ones grow quasi-exponentially. The instability growth rates and the turbulence and noise excitation strengths are derived for a simple fluid with homogeneous parameters. The linearized theory of perturbation growth is in good agreement with numerical simulations of full nonlinear thermal blooming. If the growth rate exceeds the damping rate from other phenomena, then the perturbations grow until they are limited by nonlinear saturation, at which point the beam is significantly degraded. At saturation the laser beam spontaneously breaks into small-scale transverse structures such as filaments or ribbons. The strongest damping mechanism in the open air is typically wind shear, which sets a threshold blooming rate and a threshold absorbed irradiance. Below threshold the perturbations grow linearly; above threshold they grow quasi-exponentially. Other atmospheric damping phenomena, such as diffusion and turbulent mixing, have a smaller effect.

Karr, T.; Morris, J.; Chambers, D.; Viecelli, J.; Cramer, P. (Lawrence Livermore National Laboratory, P.O. Box 808, L-495, Livermore, California 94550 (US))

1990-06-01

384

Algal-mediated ecosystem exchanges in the Eel River drainage network: towards photogrammetric mapping of color to function  

NASA Astrophysics Data System (ADS)

Seasonal algal proliferations in river networks are typically short-lived (weeks-months) but spatially extensive. They mediate important ecological and biogeochemical exchanges within and between ecosystems. We are investigating correspondence of assemblage color with ecosystem function in the nitrogen-limited Eel River of northern California. During summer base flow following winter floods, Eel algal assemblages are dominated by the green macroalga Cladophora glomerata. New growths are green, but blooms turn yellow as Cladophora filaments are colonized by epiphytic diatoms (Cocconeis spp.). Later, proliferations turn rust colored as epiphytic assemblages became dominated by Epithemia spp., diatoms that contain nitrogen-fixing cyanobacterial endosymbionts. Epithemia-encrusted Cladophora occurs at and downstream of reaches draining > 100 km2 (where summer inundated average channel widths > 25 m), coinciding with a threshold increase in concentration of total dissolved nitrogen. Areal nitrogen fixation rates are 14x higher in rusty algal proliferations than in green, and 3-4x higher than in yellow Cladophora mats. Corresponding increases in insect emergence suggest that nitrogen fixed by cyanobacterial endosymbionts is highly edible. Rates of biomass emergence from rusty Cladophora mats are 12-17 times greater than from green mats, and 8-10 times greater from rusty than from yellow Cladophora mats, because larger taxa emerge from rusty mats (Chironominae versus Ceratopogonidae in yellow mats). Photogrammetric detection of spatial coverage and color changes in algal proliferations may help us track nitrogen fluxes they mediate (riverine loading from the atmosphere via fixation, river to the watershed return via insect emergence) that link riverine to aerial, watershed, and potentially nearshore marine ecosystems at reach to basin scales.

Power, M. E.; Welter, J.; Furey, P.; Lowe, R.; Finlay, J. C.; Hondzo, M.; Limm, M.; Bode, C.; Dietrich, W. E.

2009-12-01

385

Coupling of algal biofuel production with wastewater.  

PubMed

Microalgae have gained enormous consideration from scientific community worldwide emerging as a viable feedstock for a renewable energy source virtually being carbon neutral, high lipid content, and comparatively more advantageous to other sources of biofuels. Although microalgae are seen as a valuable source in majority part of the world for production of biofuels and bioproducts, still they are unable to accomplish sustainable large-scale algal biofuel production. Wastewater has organic and inorganic supplements required for algal growth. The coupling of microalgae with wastewater is an effective way of waste remediation and a cost-effective microalgal biofuel production. In this review article, we will primarily discuss the possibilities and current scenario regarding coupling of microalgal cultivation with biofuel production emphasizing recent progress in this area. PMID:24982930

Bhatt, Neha Chamoli; Panwar, Amit; Bisht, Tara Singh; Tamta, Sushma

2014-01-01

386

U.S. National Herbarium: Algal Collection  

NSDL National Science Digital Library

The Algal Collection of the U.S. National Herbarium, part of the Smithsonian Institution's National Museum of Natural History, "is represented by over 219,548 accessioned and inventoried herbarium specimens preserved on herbarium sheets." The Collection includes estuarine, marine, freshwater, airborne, and terrestrial algae; however, macroscopic and marine comprise the principal holdings. In addition to information about the Collection, this website contains information regarding loan requests, scientific visits, and the Research Database. At present, only the Type Algal Collection can be searched online, but research inquiries of the main collection may be requested. Site visitors will also find information about staff members, algae collection and preservation, and marine floras in the Americas. Additionally, site visitors can view lists and selected abstracts of publications by Collection staff members.

387

Genomics of green algal hydrogen research  

Microsoft Academic Search

This article summarizes knowledge on genes and their respective proteins in the field of green algal hydrogen research. Emphasis is placed on recently cloned genes from the unicellular green alga Chlamydomonas reinhardtii, including HydA1 and HydA2, which encode homologous [Fe]-hydrogenases, Tla1, which encodes a chlorophyll antenna size regulatory gene, SulP, which encodes a chloroplast sulfate permease, and Sta7, which encodes

Anastasios Melis; Michael Seibert; Thomas Happe

2004-01-01

388

Tubular photobioreactor design for algal cultures  

Microsoft Academic Search

Principles of fluid mechanics, gas–liquid mass transfer, and irradiance controlled algal growth are integrated into a method for designing tubular photobioreactors in which the culture is circulated by an airlift pump. A 0.2 m3 photobioreactor designed using the proposed approach was proved in continuous outdoor culture of the microalga Phaeodactylum tricornutum. The culture performance was assessed under various conditions of

E. Molina; J. Fernández; F. G. Acién; Y. Chisti

2001-01-01

389

Liquid transportation fuels from algal oils  

NASA Astrophysics Data System (ADS)

Liquid transportation fuels from renewable sources are becoming more prominent and important in modem society. Processing of hydrocarbon oils from algae has not been studied in detail in the past, so components which have been proposed for incorporation in algal oils via genetic engineering, such as cuparene, farnesene, phytol and squalene, have been subjected to processing via catalytic cracking in a pulse reactor at different temperatures. The cracking results showed that liquid products contained numerous high octane molecules which make it feasible for use in automobiles. Additionally, canola oil, chosen as an algal oil model compound, was studied as a feed for catalytic cracking in a fixed-bed reactor at atmospheric pressure over different types of zeolites. The results showed that MFI catalysts gave the highest yield of gasoline range products and lowest coke formation. Gallium loaded MFI zeolites increased the total aromatics yield for the canola oil cracking relative to the acid form of the zeolite. Finally, algal oils were cracked on several selected zeolites, and the results showed the same trend as canola oil cracking. MFI gave the highest gasoline yield (43.8 wt%) and lowest coke (4.7 wt%). The total aromatics yield from algae oil cracking is improved 7.8 wt% when MFI is loaded with gallium.

Chen, Daichuan

390

Culturable bacterial flora associated with the dinoflagellate green Noctiluca miliaris during active and declining bloom phases in the Northern Arabian Sea.  

PubMed

A massive algal bloom of the dinoflagellate Noctiluca miliaris (green) was located in the Northern Arabian Sea by IRS-P4-2 (OCM-II) for microbiological studies, during two consecutive cruises of February-March 2009. Culturable bacterial load during bloom were ? 2-3-fold higher in comparison to non-bloom waters and ranged from 3.20 × 10(5) to 6.84 × 10(5) cfu ml(-1). An analysis of the dominant heterotrophs associated with Noctiluca bloom resulted in phylogenetic and a detailed metabolic characterization of 70 bacterial isolates from an overlapping active and declining bloom phase location near north-central Arabian Sea. The active phase flora was dominated by Gram-positive forms (70.59 %), a majority of which belonged to Bacillus (35.29 %) of Firmicutes. As the bloom declined, Gram-negative forms (61.11 %) emerged dominant, and these belonged to a diverse ?-proteobacterial population consisting of Shewanella (16.67 %) and equal fractions of a Cobetia-Pseudomonas-Psychrobacter-Halomonas population (36.11 %). A Unifrac-based principal coordinate analysis of partial 16S rDNA sequences showed significant differences among the active and declining phase flora and also with reported endocytic flora of Noctiluca (red). A nonparametric multidimensional scaling (NMDS) of antibiogram helped differentiation among closely related strains. The organic matter synthesized by N. miliaris appears to be quickly utilized and remineralized as seen from the high efficiency of isolates to metabolize various complex and simple C/N substrates such as carbohydrates, proteins/amino acids, lipids, sulfide production from organic matter, and solubilize phosphates. The ability of a large fraction of these strains (50-41.67 %) to further aerobically denitrify indicates their potential for nitrogen removal from these high-organic microniches of the Noctiluca bloom in the Arabian Sea, also known for high denitrification activity. The results indicate that culturable euphotic bacterial associates of Noctiluca are likely to play a critical role in the biogeochemical ramifications of these unique seasonally emerging tropical open-water blooms of the Northern Arabian Sea. PMID:23280496

Basu, Subhajit; Deobagkar, Deepti D; Matondkar, S G Prabhu; Furtado, Irene

2013-05-01

391

Interpretation of fluorometric chlorophyll registrations with Algal pigment analysis along a ferry transect in the Southern North Sea  

NASA Astrophysics Data System (ADS)

In 1991 chlorophyll a was measured continously by fluorometry on the ferry 'Norstar', between Zeebrugge and Hull. In order to assess the usefulness of this platform for monitoring of long-term changes in phytoplankton distribution in the southern North Sea, calibration cruises were carried out in January, April, June and August with RV 'Holland' to relate algal pigment fingerprints to the fluorescence record. Chlorophyll a concentrations, determined after HPLC separation, allowed a quantification of the continuous fluorescence signal. The relation between fluorescence and chlorophyll a content was found to be rather constant in June and August and allowed a prediction of the chlorophyll a concentration from fluorescence measurements within 21%. In Janaury and April, however, this relation was different for separate hydrographic regions. In April, a major chlorophyll derivative, an allomer indicative of degradation of algal matter, was abundant near the Belgian coast. During the decay of the Phaeocystis bloom, this high concentration of allomerized chlorophyll a increased the 'background' fluorescence signal. In January, enhancement of fluorescence caused by light scattering of non-algal suspended matter could be observed most clearly near the English coast, where the algal concentration was low (0.5 ?g·dm -3) while suspended (inorganic) matter concentration was high (30 mg·dm -3). By applying linear relations, calculated for every hydrographic region, prediction of the chlorophyll a concentration could be improved to an accuracy of 38%. An analysis of taxon-specific chlorophylls and carotenoids reveals that the distribution of individual pigments and of pigment ratios was indicative of taxonomic composition of the phytoplankton. Patterns in pigment concentrations along the section suggest the same phytoplankton abundance gradients and patchiness as revealed by the continuous fluorescence measurement. A succession in the phytoplankton population was apparent: from diatoms and traces of green algae in January, to a spring bloom of Phaeocystis in April close to the Belgian coast, to diatom dominance in June, to a mixed population of green algae, diatoms and Prymnesiophyceae (probably Coccolithophorids) in August, at the end of the vegetative season. The presence, even occasional abundance, of green algae (carrying chlorophyll b) in the southern North Sea has not been reported earlier. The allomerized chlorophyll a concentration was most abundant near the coastal ends of the section during all cruises. Apparently, the phytoplankton is an important source of detritus in the North Sea.

Althuis, Ij. A.; Gieskes, W. W. C.; Villerius, L.; Colijn, F.

392

Algal biomass production and wastewater treatment in high rate algal ponds receiving disinfected effluent.  

PubMed

Algal biomass production associated with wastewater is usually carried out in high rate algal ponds (HRAPs), which are concomitantly used in the treatment of such effluent. However, most types of wastewater have high levels of bacteria that can inhibit the growth of algal biomass by competing for space and nutrients. The objective of this study was to assess the influence of ultraviolet (UV) pre-disinfection on the performance of HRAPs used for wastewater treatment and algal biomass production. Two HRAPs were tested: one received effluent from an upflow anaerobic sludge blanket (UASB) reactor- HRAP -and the second received UASB effluent pre-disinfected by UV radiation-(UV)HRAP. Physical, chemical and microbiological parameters were monitored, as well as algal biomass productivity and daily pH and dissolved oxygen (DO) variation. The (UV)HRAP presented highest DO and pH values, as well as greater percentage of chlorophyll a in the biomass, which indicates greater algal biomass productivity. The average percentages of chlorophyll a found in the biomass obtained from the HRAP and the (UV)HRAP were 0.95 +/- 0.65% and 1.58 +/- 0.65%, respectively. However, total biomass productivity was greater in the HRAP (11.4 gVSSm(-2) day(-1)) compared with the (UV)HRAP (9.3 gVSSm(-2) day(-1)). Mean pH values were 7.7 +/- 0.7 in the HRAP and 8.1 +/- 1.0 in the (UV)HRAP, and mean values of DO percent saturation were 87 +/- 26% and 112 +/- 31% for the HRAP and the (UV)HRAP, respectively. Despite these differences, removal efficiencies of organic carbon, chemical oxygen demand, ammoniacal nitrogen and soluble phosphorus were statistically equal at the 5% significance level. PMID:24350441

Santiago, Aníbal Fonseca; Calijuri, Maria Lucia; Assemany, Paula Peixoto; Calijuri, Maria do Carmo; dos Reis, Alberto José Delgado

2013-01-01

393

Global distribution of summer chlorophyll blooms in the oligotrophic gyres  

NASA Astrophysics Data System (ADS)

Chlorophyll blooms consistently develop in the oligotrophic NE Pacific in late summer, isolated from land masses and sources of higher chlorophyll waters. These blooms are potentially driven by nitrogen fixation, or by vertically migrating phytoplankton, and a better understanding of their ubiquity could improve our estimate of the global nitrogen fixation rate. Here, global SeaWiFS chlorophyll data from 1997 to 2007 are examined to determine if similar blooms occur in other oligotrophic gyres. Our analysis revealed blooms in five other areas. Two of these are regions where blooms have been previously identified: the SW Pacific and off the southern tip of Madagascar. Previously, unnoticed summer blooms were also identified in the NE and SW Atlantic and in a band along 10°S in the Indian Ocean. There is considerable variation in the intensity and frequency of blooms in the different regions, occurring the least frequently in the Atlantic Ocean. The blooms that develop along 10°S in the Indian Ocean are unique in that they are clearly associated with a hydrographic feature, the 10°S thermocline ridge, which explains the bloom within a conventional upwelling scenario. The environment and timing of the blooms, developing in oligotrophic waters in late summer, are conducive to both nitrogen fixers and vertically migrating phytoplankton, which require a relatively stable water column. However, the specific locations of the chlorophyll blooms generally do not coincide with areas of maximum levels of nitrogen fixation or Trichodesmium. The NE Pacific chlorophyll blooms develop in a region with a very high SiO 4/NO 3 ratio, where silicate will not be a limiting nutrient for diatoms. The blooms often develop between eddies, wrapping around the periphery of anti-cyclonic features. However, none of the areas where the blooms develop have particularly high eddy kinetic energy, from either a basin-scale or a mesoscale perspective, suggesting that other factors, such as interactions with a front or dynamics associated with the critical latitude, operate in conjunction with the eddy field to produce the observed blooms.

Wilson, Cara; Qiu, Xuemei

2008-08-01

394

Sustained plankton blooms under open chaotic flows  

E-print Network

We consider a predator-prey model of planktonic population dynamics, of excitable character, living in an open and chaotic fluid flow, i.e., a state of fluid motion in which fluid trajectories are unbounded but a chaotic region exists that is restricted to a localized area. Despite that excitability is a transient phenomenon and that fluid trajectories are continuously leaving the system, there is a regime of parameters where the excitation remains permanently in the system, given rise to a persistent plankton bloom. This regime is reached when the time scales associated to fluid stirring become slower than the ones associated to biological growth.

Emilio Hernandez-Garcia; Cristobal Lopez

2003-11-26

395

Optimizing algal cultivation & productivity : an innovative, multidiscipline, and multiscale approach.  

SciTech Connect

Progress in algal biofuels has been limited by significant knowledge gaps in algal biology, particularly as they relate to scale-up. To address this we are investigating how culture composition dynamics (light as well as biotic and abiotic stressors) describe key biochemical indicators of algal health: growth rate, photosynthetic electron transport, and lipid production. Our approach combines traditional algal physiology with genomics, bioanalytical spectroscopy, chemical imaging, remote sensing, and computational modeling to provide an improved fundamental understanding of algal cell biology across multiple cultures scales. This work spans investigations from the single-cell level to ensemble measurements of algal cell cultures at the laboratory benchtop to large greenhouse scale (175 gal). We will discuss the advantages of this novel, multidisciplinary strategy and emphasize the importance of developing an integrated toolkit to provide sensitive, selective methods for detecting early fluctuations in algal health, productivity, and population diversity. Progress in several areas will be summarized including identification of spectroscopic signatures for algal culture composition, stress level, and lipid production enabled by non-invasive spectroscopic monitoring of the photosynthetic and photoprotective pigments at the single-cell and bulk-culture scales. Early experiments compare and contrast the well-studied green algae chlamydomonas with two potential production strains of microalgae, nannochloropsis and dunnaliella, under optimal and stressed conditions. This integrated approach has the potential for broad impact on algal biofuels and bioenergy and several of these opportunities will be discussed.

Murton, Jaclyn K.; Hanson, David T. (University of New Mexico, Albuquerque, NM); Turner, Tom (University of New Mexico, Albuquerque, NM); Powell, Amy Jo; James, Scott Carlton (Sandia National Laboratories, Livermore, CA); Timlin, Jerilyn Ann; Scholle, Steven (University of New Mexico, Albuquerque, NM); August, Andrew (Sandia National Laboratories, Livermore, CA); Dwyer, Brian P.; Ruffing, Anne; Jones, Howland D. T.; Ricken, James Bryce; Reichardt, Thomas A. (Sandia National Laboratories, Livermore, CA)

2010-04-01

396

Diversity and activity of marine bacterioplankton during a diatom bloom in the North Sea assessed by total RNA and pyrotag sequencing.  

PubMed

A recent investigation of bacterioplankton communities in the German Bight towards the end of a diatom-dominated spring phytoplankton bloom revealed pronounced successions of distinct bacterial clades. A combination of metagenomics and metaproteomics indicated that these clades had distinct substrate spectra and consumed different algal substrates. In this study we re-analyzed samples from the initial study by total community RNA (metatranscriptomics) and 16S rRNA gene amplicon sequencing. This complementary approach provided new insights into the community composition and expressed genes as well as the assessment of metabolic activity levels of distinct clades. Flavobacteria (genera Ulvibacter, Formosa, and Polaribacter), Alphaproteobacteria (SAR11 clade and Rhodobacteraceae) and Gammaproteobacteria (genus Reinekea and SAR92 clade) were the most abundant taxa. Mapping of the metatranscriptome data on assembled and taxonomically classified metagenome data of the same samples substantiated that Formosa and Polaribacter acted as major algal polymer degraders, whereas Rhodobacteraceae and Reinekea spp. exhibited less specialized substrate spectra. In addition, we found that members of the Rhodobacteraceae and SAR92 clade showed high metabolic activity levels, which suggests that these clades played a more important role during the bloom event as indicated by their in situ abundances. PMID:25211053

Klindworth, Anna; Mann, Alexander J; Huang, Sixing; Wichels, Antje; Quast, Christian; Waldmann, Jost; Teeling, Hanno; Glöckner, Frank Oliver

2014-12-01

397

Seeing Toxic Algae Before it Blooms By Steve Ress  

E-print Network

Seeing Toxic Algae Before it Blooms By Steve Ress Researchers at the University of Nebraska of toxic blue-green algae before the bacteria that produce it can grow into a full-scale bloom. Now UNL and monitor in real-time, the water-borne agents that can cause toxic blue- green algae to flourish and become

Nebraska-Lincoln, University of

398

Satellite-Observed Algae Blooms in China's Lake Taihu  

Microsoft Academic Search

During the spring of 2007, a massive blue-green algae (Microcystis) bloom broke out in Lake Taihu, one of the largest inland lakes in China. This freshwater lake is located in the Yangtze River delta (Figure 1), one of the world's most urbanized and heavily populated areas. The massive bloom event became an environmental crisis that prompted officials to cut tap

Menghua Wang; Wei Shi

2008-01-01

399

Effect of bloom strength on radiochromic gel dosimeters  

NASA Astrophysics Data System (ADS)

The Fricke gel dosimeter has been the widely used dosimeter among the gel dosimeters because of its dose response characteristics and easy preparation. The ferrous to ferric conversion that happens in this gel dosimeter on irradiation, corresponds to the absorbed dose of radiation. Gel dosimetry in India is not moving forward because of the import restrictions on the commercially available high bloom strength gelatin (imported 300 bloom). The feasibility of using Fricke gel dosimeter prepared with the locally available gelatin of 240 bloom and 200 bloom were compared with the 300 bloom gelatin taken as standard. The gel samples were prepared with 5% gelatin by weight and irradiated with 60Co gamma radiation for a dose range from 0-3 Gy used clinically. The optical absorption of gel samples were analyzed using spectrophotometer at 585 nm and dose response curves were generated. The results indicate that Fricke gels prepared with 240 bloom have linear dose response and comparable with those prepared with 300 bloom but the use of gels prepared with 200 bloom was found to be limited because of its poor optical transmittance.

Ebenezer Suman Babu, S.; Ravindran, B. Paul

2015-01-01

400

Enhancing counting bloom filters through Huffman-coded multilayer structures  

Microsoft Academic Search

Bloom Filters are efficient randomized data structures for membership queries on a set with a certain known false positive probability. Counting Bloom Filters (CBFs) allow the same operation on dynamic sets that can be updated via insertions and deletions with larger memory requirements. This paper first presents a simple tight upper bound for counters overflow probability in CBFs, which is

Domenico Ficara; Andrea Di Pietro; Stefano Giordano; Gregorio Procissi; Fabio Vitucci

2010-01-01

401

Is Bloom's Taxonomy Appropriate for Computer Colin G. Johnson  

E-print Network

Is Bloom's Taxonomy Appropriate for Computer Science? Colin G. Johnson Computing Laboratory's taxonomy attempts to provide a set of levels of cognitive engagement with material being learned to `benchmark' the content of a computing degree. 1. INTRODUCTION Bloom's taxonomy was devised in the 1950s

Kent, University of

402

The Evolution of Educational Objectives: Bloom's Taxonomy and beyond  

ERIC Educational Resources Information Center

It is crucial for teachers to communicate effectively about educational objectives to students, colleagues, and others in education. In 1956, Bloom developed a cognitive learning taxonomy to enhance communication between college examiners. The Bloom taxonomy consists of 6 hierarchical levels of learning (knowledge, comprehension, application,…

Fallahi, Carolyn R.; LaMonaca, Frank H., Jr.

2009-01-01

403

Teleology without a Telos?: Constitutive Absence in Leopold Bloom's Pilgrimage  

Microsoft Academic Search

The central argument of this paper highlights a search for the elusive centre in James Joyce's Ulysses. Joyce, through the figure of Leopold Bloom (and other characters), portrays pilgrimage whose form and meaning depart from the traditional sacred quest. While retaining crucial qualities of the pilgrim – even if his destination proves to be intangible –Bloom also embodies a collective

2007-01-01

404

Access-Efficient Balanced Bloom Filters Yossi Kanizo  

E-print Network

a prohibitive memory access bandwidth when either implemented in an off-chip setting (that is, requiring memory access-rate and low false positive rate. However, since Bloom Filters hash elements to arbitrary elements to a single memory block, where they maintain a local Bloom Filter. Therefore, they access only

Hay, David

405

Ocean fertilization experiments may initiate a large scale phytoplankton bloom  

E-print Network

.g. in the firing of neurons [7]. The artificial plankton bloom produced by iron fertilization experiments has on plankton has considered only the spatially homogeneous situation, and need not be relevant to the iron fertilization experiments, in which localised perturbations produce localised bloom that is subsequently

Cambridge, University of

406

Differential effects of ocean acidification on carbon acquisition in two bloom-forming dinoflagellate species.  

PubMed

Dinoflagellates represent a cosmopolitan group of phytoplankton with the ability to form harmful algal blooms. Featuring a Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) with very low CO2 affinities, photosynthesis of this group may be particularly prone to carbon limitation and thus benefit from rising atmospheric CO2 partial pressure (pCO2) under ocean acidification (OA). Here, we investigated the consequences of OA on two bloom-forming dinoflagellate species, the calcareous Scrippsiella trochoidea and the toxic Alexandrium tamarense. Using dilute batch incubations, we assessed growth characteristics over a range of pCO2 (i.e. 180-1200 µatm). To understand the underlying physiology, several aspects of inorganic carbon acquisition were investigated by membrane-inlet mass spectrometry. Our results show that both species kept growth rates constant over the tested pCO2 range, but we observed a number of species-specific responses. For instance, biomass production and cell size decreased in S. trochoidea, while A. tamarense was not responsive to OA in these measures. In terms of oxygen fluxes, rates of photosynthesis and respiration remained unaltered in S. trochoidea whereas respiration increased in A. tamarense under OA. Both species featured efficient carbon concentrating mechanisms (CCMs) with a CO2-dependent contribution of HCO3(-) uptake. In S. trochoidea, the CCM was further facilitated by exceptionally high and CO2-independent carbonic anhydrase activity. Comparing both species, a general trade-off between maximum rates of photosynthesis and respective affinities is indicated. In conclusion, our results demonstrate effective CCMs in both species, yet very different strategies to adjust their carbon acquisition. This regulation in CCMs enables both species to maintain growth over a wide range of ecologically relevant pCO2 . PMID:24320746

Eberlein, Tim; Van de Waal, Dedmer B; Rost, Björn

2014-08-01

407

Differential effects of ocean acidification on carbon acquisition in two bloom-forming dinoflagellate species  

PubMed Central

Dinoflagellates represent a cosmopolitan group of phytoplankton with the ability to form harmful algal blooms. Featuring a Ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) with very low CO2 affinities, photosynthesis of this group may be particularly prone to carbon limitation and thus benefit from rising atmospheric CO2 partial pressure (pCO2) under ocean acidification (OA). Here, we investigated the consequences of OA on two bloom-forming dinoflagellate species, the calcareous Scrippsiella trochoidea and the toxic Alexandrium tamarense. Using dilute batch incubations, we assessed growth characteristics over a range of pCO2 (i.e. 180–1200 µatm). To understand the underlying physiology, several aspects of inorganic carbon acquisition were investigated by membrane-inlet mass spectrometry. Our results show that both species kept growth rates constant over the tested pCO2 range, but we observed a number of species-specific responses. For instance, biomass production and cell size decreased in S. trochoidea, while A. tamarense was not responsive to OA in these measures. In terms of oxygen fluxes, rates of photosynthesis and respiration remained unaltered in S. trochoidea whereas respiration increased in A. tamarense under OA. Both species featured efficient carbon concentrating mechanisms (CCMs) with a CO2-dependent contribution of HCO3? uptake. In S. trochoidea, the CCM was further facilitated by exceptionally high and CO2-independent carbonic anhydrase activity. Comparing both species, a general trade-off between maximum rates of photosynthesis and respective affinities is indicated. In conclusion, our results demonstrate effective CCMs in both species, yet very different strategies to adjust their carbon acquisition. This regulation in CCMs enables both species to maintain growth over a wide range of ecologically relevant pCO2. PMID:24320746

Eberlein, Tim; Van de Waal, Dedmer B; Rost, Björn

2014-01-01

408

Phytoplankton Bloom in North Sea off Scotland  

NASA Technical Reports Server (NTRS)

The northern and western highlands of Scotland were still winter-brown and even dusted with snow in places, but the waters of the North Sea were blooming with phytoplankton on May 8, 2008, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite passed over the region and captured this image. The tiny, plant-like organisms swirled in the waters off the country's east coast, coloring the shallow coastal waters shades of bright blue and green. Phytoplankton are tiny organisms--many are just a single cell--that use chlorophyll and other pigments to capture light for photosynthesis. Because these pigments absorb sunlight, they change the color of the light reflected from the sea surface back to the satellite. Scientists have used observations of 'ocean color' from satellites for more than 20 years to track worldwide patterns in phytoplankton blooms. Phytoplankton are important to the Earth system for a host of reasons, including their status as the base of the ocean food web. In the North Sea, they are the base of the food web that supports Scotland's commercial fisheries, including monkfish and herring. As photosynthesizers, they also play a crucial role in the carbon cycle, removing carbon dioxide from the atmosphere. Some oceanographers are concerned that rising ocean temperatures will slow phytoplankton growth rates, harming marine ecosystems and causing carbon dioxide to accumulate more rapidly in the atmosphere.

2008-01-01

409

Margalef's mandala and phytoplankton bloom strategies  

NASA Astrophysics Data System (ADS)

Margalef's mandala maps phytoplankton species into a phase space defined by turbulence (A) and nutrient concentrations (Ni); these are the hard axes. The permutations of high and low A and high and low Ni divide the space into four domains. Soft axes indicate some ecological dynamics. A main sequence shows the normal course of phytoplankton succession; the r-K axis of MacArthur and Wilson runs parallel to it. An alternative successional sequence leads to the low A-high Ni domain into which many red tide species are mapped. Astronomical and biological time are implicit. A mathematical transformation of the mandala (rotation) links it to the classical bloom models of Sverdrup (time) and Kierstead and Slobodkin (space).Both rarity and the propensity to form red tides are considered to be species characters, meaning that maximum population abundance can be a target of natural selection. Equally, both the unpredictable appearance of bloom species and their short-lived appearances may be species characters. There may be a correlation too between these features and long-lived dormant stages in the life-cycle; then the vegetative planktonic phase is the 'weak link' in the life-cycle. Red tides are thus due to species which have evolved suites of traits which result in specific demographic strategies.

Wyatt, Timothy

2014-03-01

410

Algal Attributes: An Autecological Classification of Algal Taxa Collected by the National Water-Quality Assessment Program  

USGS Publications Warehouse

Algae are excellent indicators of water-quality conditions, notably nutrient and organic enrichment, and also are indicators of major ion, dissolved oxygen, and pH concentrations and stream microhabitat conditions. The autecology, or physiological optima and tolerance, of algal species for various water-quality contaminants and conditions is relatively well understood for certain groups of freshwater algae, notably diatoms. However, applications of autecological information for water-quality assessments have been limited because of challenges associated with compiling autecological literature from disparate sources, tracking name changes for a large number of algal species, and creating an autecological data base from which algal-indicator metrics can be calculated. A comprehensive summary of algal autecological attributes for North American streams and rivers does not exist. This report describes a large, digital data file containing 28,182 records for 5,939 algal taxa, generally species or variety, collected by the U.S. Geological Survey?s National Water-Quality Assessment (NAWQA) Program. The data file includes 37 algal attributes classified by over 100 algal-indicator codes or metrics that can be calculated easily with readily available software. Algal attributes include qualitative classifications based on European and North American autecological literature, and semi-quantitative, weighted-average regression approaches for estimating optima using regional and national NAWQA data. Applications of algal metrics in water-quality assessments are discussed and national quartile distributions of metric scores are shown for selected indicator metrics.

Porter, Stephen D.

2008-01-01

411

Addressing the challenges for sustainable production of algal biofuels: I. Algal strains and nutrient supply.  

PubMed

Microalgae hold promise for the production of sustainable replacement of fossil fuels due to their high growth rates, ability to grow on non-arable land and their high content, under the proper conditions, of high energy compounds that can be relatively easily chemically converted to fuels using existing technology. However, projected large-scale algal production raises a number of sustainability concerns concerning land use, net energy return, water use and nutrient supply. The state-of-the-art of algal production of biofuels is presented with emphasis on some possible avenues to provide answers to the sustainability questions that have been raised. Here, issues concerning algal strains and supply of nutrients for large-scale production are discussed. Since sustainability concerns necessitate the use of wastewaters for supply of bulk nutrients, emphasis is placed on the composition and suitability of different wastewater streams. At the same time, algal cultivation has proven useful in waste treatment processes, and thus this aspect is also treated in some detail. PMID:24350435

Abdelaziz, Ahmed E M; Leite, Gustavo B; Hallenbeck, Patrick C

2013-01-01

412

Mesozooplankton response to iron enrichment during the diatom bloom and bloom decline in SERIES (NE Pacific)  

NASA Astrophysics Data System (ADS)

A mesoscale iron-fertilization experiment was carried out in the eastern subarctic Pacific during summer 2002. The iron patch was traced for 26 days after the enrichment, and the abundance and behavior of mesozooplankton was compared with those outside of the patch during the first half of the experiment (days 2-18) by Sastri and Dower [2006. Mesozooplankton community response during the SERIES iron enrichment experiment in the subarctic NE Pacific. Deep-Sea Research Part II.) and during the post-enrichment