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1

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.

2

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.

2009-12-28

3

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.

Kane, Andrew; Jacobs, Dan; Center, Aquatic P.

4

Harmful Algal Blooms  

USGS Publications Warehouse

What are Harmful Algal Blooms (HABs)? Freshwater and marine harmful algal blooms (HABs) can occur anytime water use is impaired due to excessive accumulations of algae. HAB occurrence is affected by a complex set of physical, chemical, biological, hydrological, and meteorological conditions making it difficult to isolate specific causative environmental factors. Potential impairments include reduction in water quality, accumulation of malodorous scums in beach areas, algal production of toxins potent enough to poison both aquatic and terrestrial organisms, and algal production of taste-and-odor compounds that cause unpalatable drinking water and fish. HABs are a global problem, and toxic freshwater and (or) marine algae have been implicated in human and animal illness and death in over 45 countries worldwide and in at least 27 U.S. States (Yoo and others, 1995; Chorus and Bartram, 1999; Huisman and others, 2005).

Graham, Jennifer L.

2007-01-01

5

Harmful Algal Blooms  

NSDL National Science Digital Library

This webpage serves as a portal to the CDC's collection of harmful algal bloom (HAB) resources for the general public. Visitors can find general information about HABs, as well as focus areas targeting Cyanobacteria, Ciguatera, red tide, and Pfiesteria piscicida. Links are also provided to publications, CDC activities, and datasets (organized by federal, state, and international levels).

Branch, National C.; Prevention, Centers F.

6

Toxic & 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.

2001-03-19

7

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.

8

Models of harmful algal blooms  

Microsoft Academic Search

Models used to study harmful algal blooms are a subset of those used to examine more general planktonic processes. Most models have been heuristic, examining the likelihood of certain processes generating a harmful algal bloom. Several models have been more closely coupled to field data and have been used to gain insights into the dynamics underlying the observations. As better

Peter J. S. Franks

1997-01-01

9

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)

10

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.

Oceanography, Project

11

TEXAS HARMFUL ALGAL BLOOM COORDINATION MX964014  

EPA Science Inventory

Harmful algal blooms (HAB) are an expanding problem in coastal Texas. Nearly ¿ of the known harmful algal blooms along the Texas coast have occurred in the past ten years and have led to significant resource and tourism losses. For example, there are at least two types of toxic...

12

Harmful algal blooms: causes, impacts and detection  

Microsoft Academic Search

Blooms of autotrophic algae and some heterotrophic protists are increasingly frequent in coastal waters around the world and are collectively grouped as harmful algal blooms (HABs). Blooms of these organisms are attributed to two primary factors: natural processes such as circulation, upwelling relaxation, and river flow; and, anthropogenic loadings leading to eutrophication. Unfortunately, the latter is commonly assumed to be

Kevin G. Sellner; Gregory J. Doucette; Gary J. Kirkpatrick

2003-01-01

13

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.

Domain, Public; Center for Sponsored Coastal Ocean Research (CSCOR)

14

Harmful Algal Bloom Operational Forecast System  

NSDL National Science Digital Library

The Harmful Algal Bloom (HAB) Operational Forecast 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.

2009-06-26

15

AL HARMFUL ALGAL BLOOM (HAB) INFORMATION EXCHANGE  

EPA Science Inventory

This project proposes to implement an integrated web site that will serve as an Alabama Harmful Algal Bloom (HAB) Information Exchange Network. This network will be a stand-alone site where HAB data from all agencies and research efforts in the State of Alabama will be integrate...

16

CSCOR Harmful Algal Bloom Event Response Program  

NSDL National Science Digital Library

This NOAA Center for Sponsored Coastal Ocean Research (CSCOR) web page features the Harmful Algal Bloom Event Response Team. Over the past decade harmful algal blooms (HABs) have increased along U.S. coasts causing major resource, economic, and health impacts. State and Federal managers responding to blooms often lack timely access to cutting-edge science useful in minimizing HAB impacts on coastal communities. The NCCOS Center for Sponsored Coastal Ocean Research (CSCOR) HAB Event Response program addresses the need to inject science into management by supporting coastal managers faced with responding to unusual or unexpected HABs. This page describes how to apply for funding and accomplishments achieved by the program. Links are provided to CSCOR Event Responses.

Center for Sponsored Coastal Ocean Research (CSCOR); Noaa

17

CSCOR Harmful Algal Bloom Event Response Program  

NSDL National Science Digital Library

This NOAA Center for Sponsored Coastal Ocean Research (CSCOR) web page features the Harmful Algal Bloom Event Response Team. Over the past decade harmful algal blooms (HABs) have increased along U.S. coasts causing major resource, economic, and health impacts. State and Federal managers responding to blooms often lack timely access to cutting-edge science useful in minimizing HAB impacts on coastal communities. The NCCOS Center for Sponsored Coastal Ocean Research (CSCOR) HAB Event Response program addresses the need to inject science into management by supporting coastal managers faced with responding to unusual or unexpected HABs. This page describes how to apply for funding and accomplishments achieved by the program. Links are provided to CSCOR Event Responses.

2010-01-14

18

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

19

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

20

Toxic and Harmful Algal Blooms: A Community in Crisis  

NSDL National Science Digital Library

This activity will allow students to apply their understanding of the role of algae in the food web, the general impacts of harmful algal blooms, and ways that our societies deal with blooms in a simulated situation. Students are presented with a scenario of a recent harmful algal bloom in the fictional town of Habport. They are assigned roles and are asked to prepare for and participate in a Habport town meeting called to discuss the bloom. As the students are allowed time to discuss what occurred during their town meeting, they will better understand the broader ecological, social, and economic impact of a harmful algal bloom.

21

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

22

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...

23

Airborne Monitoring of Harmful Algal Blooms over Lake Erie.  

National Technical Information Service (NTIS)

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.

J. Lekki R. Tokars

2013-01-01

24

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

25

Harmful algal blooms and eutrophication: Nutrient sources, composition, and consequences  

Microsoft Academic Search

Although algal blooms, including those considered toxic or harmful, can be natural phenomena, the nature of the global problem\\u000a of harmful algal blooms (HABs) has expanded both in extent and its public perception over the last several decades. Of concern,\\u000a especially for resource managers, is the potential relationship between HABs and the accelerated eutrophication of coastal\\u000a waters from human activities.

Donald M. Anderson; Patricia M. Glibert; Joann M. Burkholder

2002-01-01

26

Controlling Harmful Algal Blooms Through Clay Flocculation1  

Microsoft Academic Search

ABSTRACT. The potential use of clays to control harmful algal blooms (HABs) has been explored in East Asia, Australia, the United States, and Sweden. In Japan and South Korea, minerals such as montmorillonite, kaolinite, and yellow loess, have already been used in the field effectively, to protect fish mariculture fromCochlodiniumspp. and other blooms. Cell removal occurs through the flocculation of

MARIO R. SENGCO; DONALD M. ANDERSON

2004-01-01

27

Harmful algal bloom causative collected from Hong Kong waters  

Microsoft Academic Search

Harmful algal blooms (HABs) have increased globally in recent years. In Hong Kong, a record algal bloom, caused by Gymnodinium mikimotoi and Gyrodiniumsp. HK'98 (subsequently described as Karenia digitata) occurred in March and April 1998. Almost all fishes died in the affected cages, and the estimated economic loss caused by the HAB was HK$$315?000?000 (equivalent to US $$40?000?000). Most of

Songhui Lu; I. J. Hodgkiss

2004-01-01

28

Mexico-U.S. Harmful Algal Bloom Monitoring Efforts  

NASA Astrophysics Data System (ADS)

Workshop on Taxonomy of Harmful Algal Blooms; Veracruz, Mexico, 18-22 February 2008; A workshop on harmful algal bloom (HAB) taxonomy, sponsored by the U.S. Environmental Protection Agency (EPA) and the Department of Health of the state of Veracruz, Mexico, was held at the Aquarium of Veracruz and focused on standardizing methods to detect HABs that affect coastal waters in the Gulf of Mexico. This binational effort was established under the umbrella of the Gulf of Mexico Alliance (GOMA), initially formed in 2004 by the five U.S. Gulf states (Florida, Alabama, Mississippi, Louisiana, and Texas) with participation from U.S. federal agencies and other stakeholders.

Hu, Chuanmin; Muller-Karger, Frank E.

2008-06-01

29

The Harmful Algal Bloom: Simple Plants With Toxic Implications  

NSDL National Science Digital Library

This resource provides scientific understanding, detection, monitoring, assessment, and prediction of harmful algal blooms (HABs) and hypoxia (low oxygen). Specifics are given on understanding HABs (red tide) where they occur, the climate and economic impact on the environment as well as a framework of response options.

2003-07-27

30

Eutrophication and harmful algal blooms: A scientific consensus  

Microsoft Academic Search

In January 2003, the US Environmental Protection Agency sponsored a “roundtable discussion” to develop a consensus on the relationship between eutrophication and harmful algal blooms (HABs), specifically targeting those relationships for which management actions may be appropriate. Academic, federal, and state agency representatives were in attendance. The following seven statements were unanimously adopted by attendees based on review and analysis

J. Heisler; P. M. Glibert; J. M. Burkholder; D. M. Anderson; W. Cochlan; W. C. Dennison; Q. Dortch; C. J. Gobler; C. A. Heil; E. Humphries; A. Lewitus; R. Magnien; H. G. Marshall; K. Sellner; D. A. Stockwell; D. K. Stoecker; M. Suddleson

2008-01-01

31

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

32

An overview of the interagency, International Symposium on Cyanobacterial Harmful Algal Blooms (ISOC-HAB): advancing the scientific understanding of freshwater harmful algal blooms.  

PubMed

There is growing evidence that the spatial and temporal incidence of harmful algal blooms is increasing, posing potential risks to human health and ecosystem sustainability. Currently there are no US Federal guidelines, Water Quality Criteria and Standards, or regulations concerning the management of harmful algal blooms. Algal blooms in freshwater are predominantly cyanobacteria, some of which produce highly potent cyanotoxins. The US Congress mandated a Scientific Assessment of Freshwater Harmful Algal Blooms in the 2004 reauthorization of the Harmful Algal Blooms and Hypoxia Research and Control Act. To further the scientific understanding of freshwater harmful algal blooms, the US Environmental Protection Agency (EPA) established an interagency committee to organize the Interagency, International Symposium on Cyanobacterial Harmful Algal Blooms (ISOC-HAB). A theoretical framework to define scientific issues and a systems approach to implement the assessment and management of cyanobacterial harmful algal blooms were developed as organizing themes for the symposium. Seven major topic areas and 23 subtopics were addressed in Workgroups and platform sessions during the symposium. The primary charge given to platform presenters was to describe the state of the science in the subtopic areas, whereas the Workgroups were charged with identifying research that could be accomplished in the short- and long-term to reduce scientific uncertainties. The proceedings of the symposium, published in this monograph, are intended to inform policy determinations and the mandated Scientific Assessment by describing the scientific knowledge and areas of uncertainty concerning freshwater harmful algal blooms. PMID:18461763

Hudnell, H Kenneth; Dortch, Quay; Zenick, Harold

2008-01-01

33

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

34

Study of harmful algal blooms in a eutrophic pond, Bangladesh  

Microsoft Academic Search

The purpose of this research was to analyze the underlying mechanisms and contributing factors related to the seasonal dynamic\\u000a of harmful algal blooms in a shallow eutrophic pond, Bangladesh during September 2005–July 2006. Two conspicuous events were\\u000a noted simultaneously throughout the study period: high concentration of phosphate–phosphorus (>3.03; SD 1.29 mg l???1) and permanent cyanobacterial blooms {>3,981.88 × 103 cells l???1 (SD 508.73)}. Cyanobacterial

Roksana Jahan; Saleha Khan; Joong Ki Choi

2010-01-01

35

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.

2009-12-25

36

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); Noaa

37

Harmful algal blooms: Their ecophysiology and general relevance to phytoplankton blooms in the sea  

Microsoft Academic Search

From 60 to 80 species of phytoplankton have been reported to be harmful; of thcsc, 90% are flagellates, notably dinoflagellates. The effects of turbulence on harmful algal bloom (HAB) taxa, their photoadaptive strategies, growth rate, and nutrient uptake aFlinity (K,) are considered. Flagellates, including HAB taxa, collectively have a lower nutrient uptake affinity than diatoms. Four major adaptations are suggested

Theodore J. Smayda

1997-01-01

38

Using clay to control harmful algal blooms: deposition and resuspension of clay\\/algal flocs  

Microsoft Academic Search

Harmful algal blooms (HABs) may be legitimate targets for direct control or mitigation, due to their impacts on commercial fisheries and public health. One promising control strategy is the rapid sedimentation of HABs through flocculation with clay. The objective of this study was to evaluate flow environments in which such a control strategy might be effective in removing harmful algae

Stace E. Beaulieu; Mario R. Sengco; Donald M. Anderson

2005-01-01

39

The diversity of harmful algal blooms: a challenge for science and management  

Microsoft Academic Search

A broad spectrum of events come under the category of harmful algal blooms (HABs), the common denominator being a negative impact on human activities. Harmful algal blooms involve a wide diversity of organisms, bloom dynamics, and mechanisms of impact. Here we review the effects of natural and man-induced environmental fluctuations on the frequency and apparent spreading of these phenomena. This

Adriana Zingone; Henrik Oksfeldt Enevoldsen

2000-01-01

40

Freshwater harmful algal blooms: toxins and children's health.  

PubMed

Massive accumulations of cyanobacteria (a.k.a. "blue-green algae"), known as freshwater harmful algal blooms (FHABs), are a common global occurrence in water bodies used for recreational purposes and drinking water purification. Bloom prevalence is increased due to anthropogenic changes in land use, agricultural activity, and climate change. These photosynthetic bacteria produce a range of toxic secondary metabolites that affect animals and humans at both chronic and acute dosages. Children are especially at risk because of their lower body weight, behavior, and toxic effects on development. Here we review common FHAB toxins, related clinical symptoms, acceptable concentrations in drinking water, case studies of children's and young adults' exposures to FHAB toxins through drinking water and food, methods of environmental and clinical detection in potential cases of intoxication, and best practices for FHAB prevention. PMID:24439026

Weirich, Chelsea A; Miller, Todd R

2014-01-01

41

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...

42

Status of U.S. Harmful Algal Blooms: Progress Towards a National Program.  

National Technical Information Service (NTIS)

Harmful algal blooms are an increasing worldwide threat with significant impacts on U.S. coastal regions. A harmful algal bloom (HAB) in local waters can have serious consequences, depending on the species, that range from killing fish and other wildlife ...

2005-01-01

43

Health and Ecological Impacts of Harmful Algal Blooms: Risk Assessment Needs  

Microsoft Academic Search

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 in order to provide a complete risk assessment of their impacts. Six recognized human poisoning syndromes resulting from

Frances M. Van Dolah; Daniel Roelke; Richard M. Greene

2001-01-01

44

Selective Algicidal Action of Peptides against Harmful Algal Bloom Species  

PubMed Central

Recently, harmful algal bloom (HAB), also termed “red tide”, has been recognized as a serious problem in marine environments according to climate changes worldwide. Many novel materials or methods to prevent HAB have not yet been employed except for clay dispersion, in which can the resulting sedimentation on the seafloor can also cause alteration in marine ecology or secondary environmental pollution. In the current study, we investigated that antimicrobial peptide have a potential in controlling HAB without cytotoxicity to harmless marine organisms. Here, antimicrobial peptides are proposed as new algicidal compounds in combating HAB cells. HPA3 and HPA3NT3 peptides which exert potent antimicrobial activity via pore forming action in plasma membrane showed that HPA3NT3 reduced the motility of algal cells, disrupted their plasma membrane, and induced the efflux of intracellular components. Against raphidoflagellate such as Heterosigma akashiwo, Chattonella sp., and C. marina, it displayed a rapid lysing action in cell membranes at 1?4 µM within 2 min. Comparatively, its lysing effects occurred at 8 µM within 1 h in dinoflagellate such as Cochlodium polykrikoides, Prorocentrum micans, and P. minimum. Moreover, its lysing action induced the lysis of chloroplasts and loss of chlorophyll a. In the contrary, this peptide was not effective against Skeletonema costatum, harmless algal cell, even at 256 µM, moreover, it killed only H. akashiwo or C. marina in co-cultivation with S. costatum, indicating to its selective algicidal activity between harmful and harmless algal cells. The peptide was non-hemolytic against red blood cells of Sebastes schlegeli, the black rockfish, at 120 µM. HAB cells were quickly and selectively lysed following treatment of antimicrobial peptides without cytotoxicity to harmless marine organisms. Thus, the antibiotic peptides examined in our study appear to have much potential in effectively controlling HAB with minimal impact on marine ecology.

Park, Seong-Cheol; Lee, Jong-Kook; Kim, Si Wouk; Park, Yoonkyung

2011-01-01

45

Biological control of harmful algal blooms: A modelling study  

NASA Astrophysics Data System (ADS)

A multispecies dynamic simulation model (ERSEM) was used to examine the influence of allelopathic and trophic interactions causing feeding avoidance by predators, on the formation of harmful algal blooms, under environmental scenarios typical of a Mediterranean harbour (Barcelona). The biological state variables of the model included four functional groups of phytoplankton (diatoms, toxic and non-toxic flagellates and picophytoplankton), heterotrophic flagellates, micro- and mesozooplankton and bacteria. The physical-chemical forcing (irradiance, temperature and major nutrient concentrations) was based on an actual series of measurements taken along a year cycle in the Barcelona harbour. In order to evaluate potential effects of advection, some runs were repeated after introducing a biomass loss term. Numerical simulations showed that allelopathic effects of a toxic alga on a non-toxic but otherwise similar competitor did not have appreciable influence on the dynamics of the system. However, induction of avoidance of the toxic alga by predators, which resulted on increased predation pressure on other algal groups had a significant effect on the development of algal and predator populations. The presence of advection overrided the effect of these interactions and only allowed organisms with sufficiently high potential growth rates to thrive.

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

2006-07-01

46

Feeding by ciliates on two harmful algal bloom species, Prymnesium parvum and Prorocentrum minimum  

Microsoft Academic Search

We have focused on ciliates as potential grazers on toxic phytoplankton because they are major herbivores in aquatic food webs. Ciliates may exert top down control on toxic phytoplankton blooms, potentially suppressing or shortening the duration of harmful algal blooms (HABs). We measured the growth rates of several ciliate species on uni-algal and mixed diets of both HAB and non-HAB

Carol Holmes Rosetta; George B. McManus

2003-01-01

47

An Application of Lagrangian Coherent Structures to Harmful Algal Blooms  

NASA Astrophysics Data System (ADS)

Karenia brevis is present in low concentrations in vast areas of the Gulf of Mexico (GoM). This toxic dinoflagellate sporadically develops blooms anywhere in the GoM, except in the southern portion of West Florida Shelf (WFS). There, these harmful algal blooms (HABs) are recurrent events whose frequency and intensity are increasing. HABs on the WFS are usually only evident once they have achieved high concentrations that can be detected by observation of discolored water, which may be apparent in satellite imagery; by ecological problems such as fish kills; or human health problems. Because the early development stages of HABs are usually not detected, there is limited understanding of the environmental conditions that lead to their development. Analysis of simulated surface ocean currents reveals the presence of a persistent large-scale Lagrangian coherent structure (LCS) on the southern portion of the WFS. A LCS can be regarded as a distinguished material line which divides immiscible fluid regions with distinct advection properties. Consistent with satellite-tracked drifter trajectories, this LCS on the WFS constitutes a cross-shelf barrier for the lateral transport of passive tracers. We hypothesize that such a LCS provides favorable conditions for the development of HABs. LCSs are also employed to trace the early location of an observed HAB on the WFS. Using a simplified population dynamics model we infer the factors that could possibly lead to the development of this HAB. The population dynamics model determines nitrogen in two components, nutrients and phytoplankton, which are assumed to be passively advected by simulated surface ocean currents. Two nutrient sources are inferred for the HAB whose evolution is found to be strongly tied to the simulated LCSs. These nutrient sources are found to be located near shore and likely due to land runoff.

Olascoaga, M. J.; Beron-Vera, F. J.; Brand, L. E.; Kocak, H.

2009-04-01

48

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.

Laboratory, National O.

49

A preliminary study on the mechanism of harmful algal bloom mitigation by use of sophorolipid treatment  

Microsoft Academic Search

In order to investigate a new method of mitigating the deleterious effect of harmful algal blooms (HABs), the inhibition of the glycolipid biosurfactant sophorolipid on three common harmful algae Alexandrium tamarense, Heterosigma akashiwo and Cochlodinium polykrikoides was studied. The optimum preparation condition for sophorolipid, the inhibition capability of sophorolipid and the interaction mechanism of sophorolipid on the three algal species

Xiao-Xia Sun; Joong-Ki Choi; Eun-Ki Kim

2004-01-01

50

THE TRPV1 RECEPTOR: THE INTERAGENCY, INTERNATION SYMPOSIUM ON CYANOBACTERIAL HARMFUL ALGAL BLOOMS.  

EPA Science Inventory

Background and Significance Evidence indicates that the frequency of occurrence of cyanobacterial harmful algal blooms (CHABs) is increasing in spatial and temporal extent in the US and worldwide. Cyanotoxins are among the most potent toxins known, causing death through ...

51

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); Noaa

52

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

53

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

54

Marine birds and harmful algal blooms: sporadic victims or under-reported events?  

Microsoft Academic Search

From the late Pliocene to now, blooms of toxic algae are associated with mortalities of marine birds. Given the long historical presence of harmful algal blooms (HABs) worldwide and the numbers of seabirds that feed on filter-feeding fish and shellfish, it is surprising that relatively few incidents of seabird deaths as a result of toxic algae have been reported. The

Sandra E. Shumway; Steven M. Allen; P. Dee Boersma

2003-01-01

55

MITIGATION OF HARMFUL ALGAL BLOOMS IN THE UNITED STATES USING CLAY: RESEARCH PROGRESS AND FUTURE PERSPECTIVES  

EPA Science Inventory

Throughout the United States, red tides and harmful algal blooms (HABs) pose a serious and recurrent threat to marine ecosystems, fisheries, human health, and coastal aesthetics. Here we report results from a research program investigating the use of clay dispersal for bloom cont...

56

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.

57

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

58

The distribution and impacts of harmful algal bloom species in eastern boundary upwelling systems  

NASA Astrophysics Data System (ADS)

Comparison of harmful algal bloom (HAB) species in eastern boundary upwelling systems, specifically species composition, bloom densities, toxin concentrations and impacts are likely to contribute to understanding these phenomena. We identify and describe HABs in the California, Canary, Benguela and Humboldt Current systems, including those that can cause the poisoning syndromes in humans called paralytic shellfish poisoning (PSP), diarrhetic shellfish poisoning (DSP), and amnesic shellfish poisoning (ASP), as well as yessotoxins, ichthyotoxins, and high-biomass blooms resulting in hypoxia and anoxia. Such comparisons will allow identification of parameters, some unique to upwelling systems and others not, that contribute to the development of these harmful blooms.

Trainer, V. L.; Pitcher, G. C.; Reguera, B.; Smayda, T. J.

2010-04-01

59

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...

60

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...

61

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

62

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

63

Using the molecular toolbox to compare harmful algal blooms in upwelling systems  

Microsoft Academic Search

Harmful algal blooms (HABs) are now generally recognized as occurring over a wide range of habitats from oligotrophic to hypernutrified, and appear to be expanding globally. Unlike many other ecosystems impacted by HABs, upwelling systems worldwide share a common set of physical parameters and are likely to respond similarly, regardless of locale. The Core Research Project on HABs in Upwelling

R. M. Kudela; M. D. A. Howard; B. D. Jenkins; P. E. Miller; G. J. Smith

2010-01-01

64

Toward a theory of biological-physical control of harmful algal bloom dynamics and impacts  

Microsoft Academic Search

A growing body of laboratory, field, and theoretical work suggests that the dynamics of harmful algal blooms and their impacts on other organisms are frequently controlled not only by physiological responses to local envi- ronmental conditions as modified by trophic interactions, but also by a series of interactions between biological and physical processes occurring over an extremely broad range of

Percy L. Donaghay

65

Remote sensing oceanography of a harmful algal bloom off the coast of southeastern Vietnam  

Microsoft Academic Search

Harmful algal blooms (HABs) in the southeastern Vietnamese coastal waters have caused large economic losses in aquacultured and wild fisheries in recent years; however, there have been few oceanographic studies on these HAB events. The present study reports an extensive HAB off southeastern Vietnamese waters during late June to July 2002 with in situ observations and analyzes the oceanographic conditions

Dan Ling Tang; Hiroshi Kawamura; Hai Doan-Nhu; Wataru Takahashi

2004-01-01

66

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

Microsoft Academic Search

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

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

2008-01-01

67

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

68

Some observations on harmful algal bloom (HAB) events along the coast of Guangdong, southern China in 1998  

Microsoft Academic Search

The year 1998 was an unusual year for Guangdong Province and Hong Kong, both in southern China, as the frequency and intensity of harmful algal blooms (HAB) were much higher than usual. This paper describes the causative organisms found associated with these blooms and speculates on the possible causes of these blooms, including the effects of increased temperature, reduced salinity,

Yuzao Qi; Jufang Chen; Zhaohui Wang; Ning Xu; Yan Wang; Pingping Shen; Songhui Lu; I. J. Hodgkiss

2004-01-01

69

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...

70

How does eutrophication affect the role of grazers in harmful algal bloom dynamics?  

Microsoft Academic Search

Population dynamics of harmful algal bloom species are regulated both from the “bottom-up” by factors that affect their growth rate and from the “top-down” by factors that affect their loss rates. While it might seem apparent that eutrophication would have the greatest impact on factors affecting growth rates of phytoplankton (nutrient supply, light availability) the roles of top-down controls, including

Edward J. Buskey

2008-01-01

71

Harmful Algal Blooms in South Carolina Residential and Golf Course Ponds  

Microsoft Academic Search

The South Carolina coastal zone is among the fastest growing areas in the U.S., and population epicenters are marked by dense brackish water pond (lagoon) coverage associated with housing complexes and golf courses. Surveillance efforts in 2001–2002 documented the widespread occurrence of several types of potentially or measurably toxic harmful algal blooms (HABs) in these ponds. These man-made retention ponds

Alan J. Lewitus; Laura B. Schmidt; Larissa J. Mason; Jason W. Kempton; Susan B. Wilde; Jennifer L. Wolny; B. Jamie Williams; Kenneth C. Hayes; Sabrina N. Hymel; Charles J. Keppler; Amy H. Ringwood

2003-01-01

72

Mathematical modelling of harmful algal blooms supported by experimental findings  

Microsoft Academic Search

In this paper non-toxic phytoplankton, toxin producing phytoplankton and zooplankton (NTP–TPP–Zooplankton) system is proposed and analyzed. It is assumed that the grazing pressure of zooplankton reduce due to presence of toxin producing phytoplankton. It is observed that TPP free steady state is unstable in nature and depicts bloom phenomena, whereas in the presence of TPP the system settles down to

J. Chattopadhyay; R. R. Sarkar; S. Pal

2004-01-01

73

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

74

Feeding rates and abundance of marine invertebrate planktonic larvae under harmful algal bloom conditions off Vancouver Island  

Microsoft Academic Search

The interactions between toxic phytoplankton and their potential grazers are poorly understood aspects of the ecology of harmful algal blooms. In this study, we determined the feeding rates, prey selection and trophic impact of different marine invertebrate planktonic larvae on the natural bloom of Heterosigma akashiwo and Prorocentrum triestinum which occurred on the west coast of Vancouver Island in July

Rodrigo Almeda; Amber M. Messmer; Nagore Sampedro; Louis A. Gosselin

2011-01-01

75

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

76

Design and Implementation of Harmful Algal Bloom Diagnosis System Based on J2EE Platform  

NASA Astrophysics Data System (ADS)

According to the shortcomings which are time consuming and laborious of the traditional HAB (Harmful Algal Bloom) diagnosis by the experienced experts using microscope, all kinds of methods and technologies to identify HAB emerged such as microscopic images, molecular biology, characteristics of pigments analysis, fluorescence spectra, inherent optical properties, etc. This paper proposes the design and implementation of a web-based diagnosis system integrating the popular methods for HAB identification. This system is designed with J2EE platform based on MVC (Model-View-Controller) model as well as technologies such as JSP, Servlets, EJB and JDBC.

Guo, Chunfeng; Zheng, Haiyong; Ji, Guangrong; Lv, Liang

77

Some observations on harmful algal bloom (HAB) events along the coast of Guangdong, southern China in 1998  

Microsoft Academic Search

\\u000a The year 1998 was an unusual year for Guangdong Province and Hong Kong, both in southern China, as the frequency and intensity\\u000a of harmful algal blooms (HAB) were much higher than usual. This paper describes the causative organisms found associated with\\u000a these blooms and speculates on the possible causes of these blooms, including the effects of increased temperature, reduced\\u000a salinity,

Yuzao Qi; Jufang Chen; Zhaohui Wang; Ning Xu; Yan Wang; Pingping Shen; Songhui Lu; I. J. Hodgkiss

78

A marine algicidal actinomycete and its active substance against the harmful algal bloom species Phaeocystis globosa.  

PubMed

A strain O4-6, which had pronounced algicidal effects to the harmful algal bloom causing alga Phaeocystis globosa, was isolated from mangrove sediments in the Yunxiao Mangrove National Nature Reserve, Fujian, China. Based on the 16S rRNA gene sequence and morphological characteristics, the isolate was found to be phylogenetically related to the genus Streptomyces and identified as Streptomyces malaysiensis O4-6. Heat stability, pH tolerance, molecular weight range and aqueous solubility were tested to characterize the algicidal compound secreted from O4-6. Results showed that the algicidal activity of this compound was not heat stable and not affected by pH changes. Residue extracted from the supernatant of O4-6 fermentation broth by ethyl acetate, was purified by Sephadex LH-20 column and silica gel column chromatography before further structure determination. Chemical structure of the responsible compound, named NIG355, was illustrated based on quadrupole time-of-flight mass spectrometry (Q-TOF-MS) and nuclear magnetic resonance (NMR) spectra. And this compound showed a stronger algicidal activity compared with other reported algicides. Furthermore, this article represents the first report of an algicide against P. globosa, and the compound may be potentially used as a bio-agent for controlling harmful algal blooms. PMID:23224407

Zheng, Xiaowei; Zhang, Bangzhou; Zhang, Jinlong; Huang, Liping; Lin, Jing; Li, Xinyi; Zhou, Yanyan; Wang, Hui; Yang, Xiaoru; Su, Jianqiang; Tian, Yun; Zheng, Tianling

2013-10-01

79

Using MODIS medium-resolution bands to monitor harmful algal blooms  

NASA Astrophysics Data System (ADS)

MODIS medium-resolution (250- and 500-m) bands were successfully used to detect and map the distribution of a harmful phytoplankton bloom (HAB) in the Paracas Bay, Peru, that caused economic losses estimated at about $28.5 million. A Red-Green-Blue combination of bands 1, 4 and 3 was used to visually distinguish the HAB while the turbidity index, a semi-quantitative measure of the amount of particulate material in the near-surface water, was used to estimate the intensity of the HAB. The turbidity index was inversely correlated with oxygen concentration in the bay. Temporary anoxia caused by the HAB was probably the main mechanism causing fish kills. The 250-m resolution provided by MODIS bands 1 and 2 is essential to detect localized HABs in coastal areas. While turbidity is not specific to algal blooms, it is a quantitative estimate of the intensity of the bloom once the existence of the bloom is detected by the RGB images.

Kahru, Mati; Mitchell, B. Greg; Diaz, Anibal

2005-08-01

80

Future increase in harmful algal blooms in the North Sea due to climate change.  

PubMed

In temperate seas such as the North Sea harmful (toxic) algal blooms will probably increase as a result of climate change. This conclusion was reached after investigating the projected effect of climate change for the year 2100 in Dutch coastal waters (4 degrees C temperature rise and increased water column stratification) on the growth rates of six harmful and two non-harmful phytoplankton species. Micro algae form the basis of the marine food chain. However, toxin-producing species may seriously disrupt the food web and lead to fish kills and human intoxication. Two species with estimated doubled growth rates in 2100, F. japonica and C. antiqua, entered Europe via ship's ballast water or shellfish imports. This stresses the need to legally regulate such invasion routes in order to prevent the import of novel species. Future toxic phytoplankton blooms may further devaluate ecosystem deliverables such as fish production or recreational use. This devaluation can be estimated by monetary value assessments that are needed in cost-benefit analyses for policy guidance. The lack of understanding of future climate, ecosystem functioning and its response to climate change calls for a scientific effort to improve our knowledge on present day coastal ecosystem functioning and its resilience. PMID:15918356

Peperzak, L

2005-01-01

81

Annual Report of the Gulf of Mexico Harmful Algal Bloom Operational Forecast System (GOM HAB-OFS). Operational Year No. 1, October 1, 2004 to September 30, 2005.  

National Technical Information Service (NTIS)

On October 1, 2004, a harmful algal bloom forecast system for the Gulf of Mexico was successfully transitioned from research to operational status, creating the Gulf of Mexico Harmful Algal Bloom Operational Forecast System (GOM HAB-OFS). During the follo...

2006-01-01

82

Are interactive effects of harmful algal blooms and copper pollution a concern for water quality management?  

PubMed

Toxicity of mixtures of stressors is one of the major challenges in water quality management. Yet until now risk assessment focuses almost exclusively on the effect characterization of individual stressors. An important concern is the potential interactive effects of cyanobacteria, sometimes referred to as harmful algal blooms, with chemical stressors. Here, we evaluated the response of two clones of the freshwater cladoceran Daphnia magna to the combined effects of five cyanobacteria and copper. The latter remains the most commonly applied chemical algaecide and is also often detected in eutrophic run-offs that promote harmful algal blooms. Because the different cyanobacteria studied here have known modes of action that are similar, as well as dissimilar compared to the known modes of actions of copper, we based our assessment on two widely used reference models, i.e. the Concentration Addition (CA) model for similarly acting stressors and the Independent Action (IA) model for dissimilarly acting stressors. We highlight four major findings. First, the conclusions drawn on the interaction type (non-interaction vs. synergism or antagonism) between either of the five cyanobacteria species and copper were the same for both D. magna clones. Second, the interaction type differed between the Microcystis + copper mixture (non-interaction according to CA and synergism according to IA) and the four other cyanobacteria + copper mixtures (antagonism according to CA and non-interaction according to IA). Third, both reference models provided reasonable predictions for all observed mixture toxicities. Fourth, we consistently obtained different results with the IA reference model compared to the CA model. More specifically, mixtures of Cu and Microcystis were synergistic with IA whereas non-interaction was observed with CA, while the remaining four cyanobacteria + copper combinations all displayed non-interaction with IA and antagonism with CA. Despite the IA reference model providing a marginally better fit to the data in general, the CA reference model delivered more conservative predictions for mixture toxicity of cyanobacteria + copper in all cases compared to the IA reference model. Thus, the CA model could serve as a conservative model to account for mixture toxicity of cyanobacteria and copper in water quality management, as it gives rise to conservative predictions of mixed stressor toxicity at sub-lethal effect levels in D. magna. Finally, and in accordance with other studies of cyanobacteria + chemical mixtures, we did not detect any strong synergistic effects of copper and cyanobacteria mixtures on D. magna. Consequently, based on our study with the model freshwater zooplankton species Daphnia, interactive effects of harmful algal blooms and copper pollution appear to be of limited concern for water quality management. PMID:24821194

Hochmuth, Jennifer D; Asselman, Jana; De Schamphelaere, Karel A C

2014-09-01

83

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.

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

2011-01-01

84

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.

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

2010-01-01

85

The economic effects of harmful algal blooms in the United States: Estimates, assessment issues, and information needs  

Microsoft Academic Search

During the last several decades, harmful algal bloom (HAB) events have been observed in more locations than ever before throughout\\u000a the United States. Scientists have identified a larger number of algal species involved in HABs, more toxins have been uncovered,\\u000a and more fisheries resources have been affected. Whether this apparent increase in HAB events is a real phenomenon or is

P. Hoagland; D. M. Anderson; Y. Kaoru; A. W. White

2002-01-01

86

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

87

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

88

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.

Anderson, Donald M.

2009-01-01

89

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.

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

90

Molecular detection of harmful algal blooms (HABs) using locked nucleic acids and bead array technology  

PubMed Central

Harmful algal blooms (HABs) are a serious public health risk in coastal waters. As the intensity and frequency of HABs continue to rise, new methods of detection are needed for reliable identification. Herein, we developed a high-throughput, multiplex, bead array technique for the detection of the dinoflagellates Karenia brevis and Karenia mikimotoi. The method combined the Luminex detection system with two novel technologies: locked nucleic acid–modified oligonucleotides (LNA) and Mirus Label IT® nucleic acid technology. To study the feasibility of the method, we evaluated the performance of modified and unmodified LNA probes with amplicon targets that were biotin labeled with two different strategies: direct chemical labeling (Mirus Label IT) versus enzymatic end-labeling (single biotinylated primer). The results illustrated that LNA probes hybridized to complementary single-stranded DNA with better affinity and displayed higher fluorescence intensities than unmodified oligonucleotide DNA probes. The latter effect was more pronounced when the assay was carried out at temperatures above 53°C degree. As opposed to the enzymatic 5? terminal labeling technique, the chemical-labeling method enhanced the level of fluorescence by as much as ~83%. The detection limits of the assay, which were established with LNA probes and Mirus Label IT system, ranged from 0.05 to 46 copies of rRNA. This high-throughput method, which represents the first molecular detection strategy to integrate Luminex technology with LNA probes and Mirus Label IT, can be adapted for the detection of other HABs and is well suited for the monitoring of red tides at pre-blooming and blooming conditions.

Diaz, Mara R.; Jacobson, James W.; Goodwin, Kelly D.; Dunbar, Sherry A.; Fell, Jack W.

2010-01-01

91

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.

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

2008-01-01

92

A pilot project to detect and forecast harmful algal blooms in the northern Gulf of Mexico.  

PubMed

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-driven, end-to-end (measurements to applications) observing system. A key strategy of the project is to coordinate existing state, federal and academic programs at an unprecedented level of collaboration and partnership. Resource managers charged with protection of public health and aquatic resources require immediate notice of algal events and a forecast of when, where and what adverse effects will likely occur. Further, managers require integrated analyses and interpretations, rather than raw data, to make effective decisions. Consequently, a functional observing system must collect and transform diverse measurements into usable forecasts. Data needed to support development of forecasts will include such properties as sea surface temperature, winds, currents and waves; precipitation and freshwater flows with related discharges of sediment and nutrients; salinity, dissolved oxygen, and chlorophyll concentrations (in vivo fluorescence); and remotely-sensed spatial images of sea surface chlorophyll concentrations. These data will be provided via a mixture of discrete and autonomous in situ sensing with near real-time data telemetry, and remote sensing from space (SeaWiFS), aircraft (hyperspectral imagery) or land (high-frequency radar). With calibration across these platforms, the project will ultimately provide a 4-dimensional visualization of harmful algae events in a time frame suitable to resource managers. PMID:12620029

Fisher, William S; Malone, Thomas C; Giattina, James D

2003-01-01

93

A preliminary assessment of harmful algal blooms in Kuwait's marine environment  

Microsoft Academic Search

Microalgal blooms occur in Kuwait's waters year round. Seasonal non-harmful blooms are part of the annual succession in marine ecosystems and are a typical phenomenon in Kuwait's waters as well as in the Gulf region. The ecology and taxonomy of phytoplankton in Kuwait's waters have been studied during the past few decades; however, only very limited detailed taxonomical studies have

Faiza Al-Yamani; Maria Saburova; Igor Polikarpov

2012-01-01

94

In situ and satellite observations of a harmful algal bloom and water condition at the Pearl River estuary in late autumn 1998  

Microsoft Academic Search

Harmful algal blooms (HABs) have posed a serious threat to the aquaculture and fisheries industries in recent years, especially in Asia. During 1998 there were several particularly serious blooms in the coastal waters of south China, which caused a serious damage to aquaculture. We report a massive dinoflagellate bloom near the mouth of Pearl River in November 1998 with analyses

DanLing Tang; Dana R. Kester; I-Hsun Ni; YuZao Qi; Hiroshi Kawamura

2003-01-01

95

Evidence for a novel marine harmful algal bloom: Cyanotoxin (Microcystin) transfer from land to sea otters  

USGS Publications Warehouse

"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.

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

96

Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters  

PubMed Central

“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.

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

97

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

98

Evaluation of the Harmful Algal Bloom Mapping System (HABMapS) and Bulletin  

NASA Technical Reports Server (NTRS)

The National Oceanic and Atmospheric Administration (NOAA) Harmful Algal Bloom (HAB) Mapping System and Bulletin provide a Web-based geographic information system (GIS) and an e-mail alert system that allow the detection, monitoring, and tracking of HABs in the Gulf of Mexico. NASA Earth Science data that potentially support HABMapS/Bulletin requirements include ocean color, sea surface temperature (SST), salinity, wind fields, precipitation, water surface elevation, and ocean currents. Modeling contributions include ocean circulation, wave/currents, along-shore current regimes, and chlorophyll modeling (coupled to imagery). The most immediately useful NASA contributions appear to be the 1-km Moderate Resolution Imaging Spectrometer (MODIS) chlorophyll and SST products and the (presently used) SeaWinds wind vector data. MODIS pigment concentration and SST data are sufficiently mature to replace imagery currently used in NOAA HAB applications. The large file size of MODIS data is an impediment to NOAA use and modified processing schemes would aid in NOAA adoption of these products for operational HAB forecasting.

Hall, Callie; Zanoni, Vicki; Estep, Leland; Terrie, Gregory; D'Sa, Eurico; Pagnutti, Mary

2004-01-01

99

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

100

Dinoflagellate community structure from the stratified environment of the Bay of Bengal, with special emphasis on harmful algal bloom species  

Microsoft Academic Search

Harmful algal blooms (HABs) have been documented along the coasts of India and the ill effects felt by society at large. Most\\u000a of these reports are from the Arabian Sea, west coast of India, whereas its counterpart, the Bay of Bengal (BOB), has remained\\u000a unexplored in this context. The unique characteristic features of the BOB, such as large amount of

Ravidas Krishna Naik; Sahana Hegde; Arga Chandrashekar Anil

101

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

102

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

2013-01-01

103

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.

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

2013-01-01

104

Watershed management strategies to prevent and control cyanobacterial harmful algal blooms.  

PubMed

The tenets of watershed management--a focus on the land area linked to the water body, the incorporation of sound scientific information into the decision-making process and stakeholder involvement throughout the process--are well-suited for the management of cyanobacterial harmful algal blooms (C-HABs). The management of C-HABs can be viewed as having two main areas of focus. First, there is mitigation--control and/or removal of the bloom. This type of crisis response is an important component to managing active C-HABs and there are several techniques that have been successfully utilized, including the application of algicides, physical removal of surface scums and the mechanical mixing of the water column. While these methods are valuable because they address the immediate problem, they do not address the conditions that exist in the system that promote and maintain C-HABs. Thus, the second component of a successful C-HAB management strategy would include a focus on prevention. C-HABs require nutrients to fuel their growth and are often favored in longer-residence time systems with vertical stratification of the water column. Consequently, nutrients and hydrology are the two factors most commonly identified as the targets for prevention of C-HABs. Management strategies to control the sources, transformation and delivery of the primary growth-limiting nutrients have been applied with success in many areas. The most effective of these include controlling land use, maintaining the integrity of the landscape and applying best management practices. In the past, notable successes in managing C-HABs have relied on the reduction of nutrients from point-sources. Because many point sources are now well-managed, current efforts are focused on non-point source nutrient reduction, such as runoff from agricultural and urban areas. Non-point sources present significant challenges due to their diffuse nature. Regardless of which techniques are utilized, effective watershed management programs for decreasing the prevalence of C-HABs will require continuing efforts to integrate science and management activities. Ultimately, it is increased coordination among stakeholders and scientists that will lead to the development of the decision-making tools that managers require to effectively weigh the costs and benefits of these programs. PMID:18461773

Piehler, Michael F

2008-01-01

105

Riverine nutrients fluxes to the North Sea and harmful algal blooms, what changed since 1984 ?  

NASA Astrophysics Data System (ADS)

Nutrients fluxes delivered to the coastal zones reflect human activities taking place within watersheds. Silica (Si) fluxes mainly originate from soils and rocks weathering, so they are few impacted by human activities. On the contrary, nitrogen (N) and phosphorus (P) fluxes are dramatically impacted by human activities. N originates from urban waste water but mainly from agricultural activities. P originates mostly from urban and industrial waste waters. The enrichment of the hydrosystems in N and P leads to an imbalance between N and P in one hand and Si in the other hand. This imbalance leads to harmful algal blooms, which are damaging aquatic ecosystems, fishing activities and touristic activities. In 1992, the OSPAR convention was signed by 15 European States and targets to decrease the N and P fluxes delivered to the European coastal zones by 50 % with respect to the reference year of 1985. Focusing on the Seine, Somme and Scheldt watersheds (France and Belgium) and the adjacent coastal zone of the North Sea, we developed a retrospective modelling from 1984 to 2007 calculating nutrients fluxes from watersheds and Phaeocystis blooms occurring in the coastal zone. We coupled the biogeochemical deterministic model Seneque/Riverstrahler depicting processes occurring within hydrological networks with the marine model MIRO simulating Phaeocystis blooms in the coastal zone. The evolution of N and P fluxes were highly dissimilar. Indeed, P mainly originates from point sources. Thereby the banishment of P from the washing powders during the nineties, the development of sewage and the improvement of WWTP in terms of waste water treatment lead to a decrease of P fluxes delivered to the coastal zone. This decrease can be observed for the three watersheds. The P OSPAR objective is achieved since the middle of the 2000's years. On the other side, N, mostly originating from agricultural diffuse sources, did not decrease over the period. The fluxes even increased at the outlet of the Seine River. This slackness or increase can be explained by the inefficiency of the measures taken in order to manage agricultural pollutions. The N OSPAR objective is still not yet achieved and no decreasing trend can be observed. Concerning the coastal zone, Phaeocystis blooms decreased by 50 % in terms of intensity and duration over the period. Our simulations permit us to show that, P availability is the main explaining factor of the Phaeocystis development. As the main major efforts have been focused on the P abatement over the period and the corresponding OSPAR objective is now achieved, the nowadays challenge is the decrease of N fluxes. Although Phaeocystis are well controlled by P, other toxic algae (as Dinoflagellates) could be driven by N availability. Moreover, high concentration of N within continental hydrological networks is damaging for aquatic ecosystems and is a major threat for producing drinking water.

Passy, Paul; Gypens, Nathalie; Billen, Gilles; Garnier, Josette; Thieu, Vincent; Rousseau, Véronique; Callens, Julie; Parent, Jean-Yves; Lancelot, Christiane

2013-04-01

106

Applications of Satellite Ocean Color Sensors for Monitoring and Predicting Harmful Algal Blooms  

Microsoft Academic Search

The new satellite ocean color sensors offer a means of detecting and monitoring algal blooms in the ocean and coastal zone. Beginning with SeaWiFS (Sea Wide Field-of-view Sensor) in September 1997, these sensors provide coverage every 1 to 2 days with 1-km pixel view at nadir. Atmospheric correction algorithms designed for the coastal zone combined with regional chlorophyll algorithms can

Richard P. Stumpf

2001-01-01

107

Examining Climate Influences and Economic Impacts of Harmful Algal Blooms in Massachusetts: 1993 and 2005  

NASA Astrophysics Data System (ADS)

Although the potential causes of harmful algal blooms (HABs), or red tides, have been studied extensively, the relationships between the environmental drivers and economic impacts have not been fully explored. This paper examined the environmental-economic link by investigating similarities in the environmental conditions leading to the 1993 and 2005 HABs (caused by the dinoflagellate Alexandirum) along the Massachusetts coast, and the resulting effects on shellfish, public health, recreation, tourism, and the commercial shellfish industry in Massachusetts. Environmental influences including sea surface temperature (SST), salinity, precipitation, streamflow, and shellfish toxicity levels were examined for the years 1990 to 2005. Economic impacts on commercial fishery landings (Massachusetts mussel commercial fishery landings and Gloucester commercial fishery landings) were assessed for the years1990 to 2003. The Plume Advection hypothesis was studied and results showed that runoff from the five major rivers that contribute to the Western Maine Coastal Current, the current that carried these cells, peaked in April 1993 and 2005 relative to the mean which varied from river to river. The most intense wind stress coming from the North occurred in April 1993 and May 2005 with speeds of 15-20 m/s. A large decrease in salinity off the Massachusetts coast occurred in May 1993 and measured outside the 68% of 1993 salinity data recorded, and from the information available, in April and May 2005 waters were also less saline. Peaks in shellfish toxicity occurred in early June 1993 at approximately 400 ?g toxicity/g shellfish meat and in 2005 at 700 ?g toxicity/g shellfish meat. This indicated a lag time between peaks in runoff and toxicity of approximately one month and similarly with decreases in salinity. Runoff also corresponded to a large decrease in salinity during May 1993. Coincidentally, there was also a significant decrease in commercial fishery landings between 1992 and 1993, resulting in a decrease of millions of dollars of revenue for shellfish fishermen and the state of Massachusetts. The 2005 red tide affected 1700 shellfish fisherman and there was a projected loss of 527 million dollars for the 2005 Massachusetts shellfish season. Effects to tourism and public health for 1993 and 2005 were challenging to assess, however, due to scarcity of accurate information. Changing fishery policies affected commercial fishery landings during the same time and were also considered. These results argue for more accurate forecasts that will help predict future HABs, as well as improved methods to provide more reliable information on the economic impacts of HABs to minimize the negative impacts of future HABs.

Ngo, N.

2005-12-01

108

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

109

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

110

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

111

Optical detection and assessment of algal blooms  

Microsoft Academic Search

Concerns about harmful algal blooms (HABs) have grown in recent years. There is a pressing need for robust, quantitative, and cost-effective methods to detect and characterize algal blooms. Critical applications of these meth- ods include long-term monitoring of coastal waters to indicate the degree to which present trends of HABs and human activities are linked, early warning systems to protect

John J. Cullen; Aurea M. Ciotti; Richard F. Davis; Marlon R. Lewis

112

Detection of Harmful Algal Blooms in the Optically Complex Coastal Waters of the Kuwait Bay using Aqua-MODIS data  

NASA Astrophysics Data System (ADS)

In the optically complex coastal marine waters of the Kuwait Bay, the propagation of Harmful Algal Blooms (HABs) has become a severe issue over the last decade affecting aquaculture a primary component of the Kuwaiti economy. Although several remote sensing based methods of algal bloom detection exist today, few may accurately detect the concentration and identify the type of HABs in Case II waters. The purpose of this study is: (1) assessment of the method that best detects and identifies algal blooms in general and HABs in particular, in the Kuwait Bay, and (2) identification of the factors controlling the occurrence of HABs. Fluorescence Line Height (FLH), Empirical, Bio-Optical, and Operational Methods as well as Ocean Colour 3 Band Ratio (OC3M), Garver-Siegel-Maritorena Model (GSM), and General Inherent Optical Property (GIOP) Chlorophyll-a (Chl-a) algorithms were applied to Moderate Resolution Imaging Spectroradiometer (MODIS) images acquired (07/2002 to 07/2012) over the Kuwait Bay and areas as far east as Shatt Al-Arab and as far south as N. 29.284 (Lat.), E. 50.047 (Long.) decimal degrees. In-situ data (bloom days: 50; sampling locations: 64) collected (09/1999 to 07/2011) from the Kuwait Bay was provided by the Kuwait Institute for Scientific Research and was used to test the reliability of the satellite-based inferences. Tasks accomplished and findings reached include: (1) comparison of in situ to estimated OC3M, GSM, and GIOP chlorophyll concentrations over the sampling locations for the time period 2002 to 2009 showed that OC3M outperformed the two other techniques in predicting the observed distribution and in replicating the measured concentration of the in-situ Chl-a data; (2) applying the OC3M algorithm to a total of 4039 scenes and using threshold values of 3, 4, and 5 mg/m3 Chl-a concentrations we inferred 371, 202, and 124 occurrences in the Kuwait Bay that met their respective threshold; (3) applying the operational method we successfully identified 13 of the reported blooms in Kuwait Bay on cloud free days; the majority of the unidentified events were on cloudy days. This was accomplished by generating difference images between the current satellite OC3M Chl-a concentration image and a background (mean of previous 60 days + 1 mg/m3) using a 14-day window between the analyzed image and those used in the generation of the mean. Predicted blooms in the Kuwait Bay in years 2002 through 2012 are 30, 84, 101, 96, 100, 97, 66, 60, 91, 81 and 29 blooms, respectively. These estimates exceed the observed occurrences and may be attributed to sampling bias (most blooms found >2 km from the shoreline) or due to uncertainties introduced by applying the OC3M algorithms to shallow water (mean depth Kuwait Bay: 22 m) cases; and (4) the temporal correlation of the distribution of the algal blooms in Kuwait Bay with those at the mouth of Shatt Al-Arab suggests a causal effect. Further efforts to more accurately identify HABS and to reduce uncertainties in Chl-a concentration are currently underway.

Manche, C. J.; Sultan, M.; Uddin, S.; Al-Dousari, A.; Chouinard, K.

2013-12-01

113

Marine downscaling of a future climate scenario in the North Sea and possible effects on dinoflagellate harmful algal blooms.  

PubMed

Two hydrodynamic and ecological models were used to investigate the effects of climate change-according to the IPCC A1b emission scenario - on the primary productivity of the North Sea and on harmful algal blooms. Both models were forced with atmospheric fields from a regional downscaling of General Circulation Models to compare two sets of 20-year simulations representative of present climate (1984-2004) conditions and of the 2040s. Both models indicated a general warming of the North Sea by up to 0.8°C and a slight freshening by the 2040s. The models suggested that the eastern North Sea would be subjected to more temperature and salinity changes than the western part. In addition, the ecological modules of the models indicated that the warming up of the sea would result in a slightly earlier spring bloom. The one model that also computes the distribution of four different phytoplankton groups suggests an increase in the abundance of dinoflagellates, whereas the abundance of diatoms, flagellates and Phaeocystis sp. remains comparable to current levels, or decrease. Assuming that Dinophysis spp. would experience a similar increase in abundance as the modelled group of dinoflagellates, it is hypothesised that blooms of Dinophysis spp. may occur more frequently in the North Sea by 2040. However, implications for shellfish toxicity remain unclear. PMID:22920935

Friocourt, Y F; Skogen, M; Stolte, W; Albretsen, J

2012-01-01

114

Dinoflagellate community structure from the stratified environment of the Bay of Bengal, with special emphasis on harmful algal bloom species.  

PubMed

Harmful algal blooms (HABs) have been documented along the coasts of India and the ill effects felt by society at large. Most of these reports are from the Arabian Sea, west coast of India, whereas its counterpart, the Bay of Bengal (BOB), has remained unexplored in this context. The unique characteristic features of the BOB, such as large amount of riverine fresh water discharges, monsoonal clouds, rainfall, and weak surface winds make the area strongly stratified. In this study, 19 potentially harmful species which accounted for approximately 14% of the total identified species (134) of dinoflagellates were encountered in surface waters of the BOB during November 2003 to September 2006. The variations in species abundance could be attributed to the seasonal variations in the stratification observed in the BOB. The presence of frequently occurring HAB species in low abundance (? 40 cell L(?-1)) in stratified waters of the BOB may not be a growth issue. However, they may play a significant role in the development of pelagic seed banks, which can serve as inocula for blooms if coupled with local physical processes like eddies and cyclones. The predominance of Ceratium furca and Noctiluca scintillans, frequently occurring HAB species during cyclone-prone seasons, point out their candidature for HABs. PMID:21210213

Naik, Ravidas Krishna; Hegde, Sahana; Anil, Arga Chandrashekar

2011-11-01

115

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

116

Algal bloom-associated disease outbreaks among users of freshwater lakes-United States, 2009 - 2010  

EPA Science Inventory

?Algal blooms? are local abundances of phytoplankton ? microscopic photosynthesizing aquatic organisms found in surface waters worldwide; blooms are variable temporally and spatially and frequently produce a visible algal scum on the water. Harmful algal blooms (HABs) are abundan...

117

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...

118

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

119

Streptomyces alboflavus RPS and its novel and high algicidal activity against harmful algal bloom species Phaeocystis globosa.  

PubMed

Phaeocystis globosa blooms have frequently occurred along coastal waters and exerted serious impacts on ecological environments by releasing toxic hemolytic substances, forming nuisance foam, and causing oxygen depletion. An actinomycete strain RPS with high algicidal activity against P. globosa was isolated and identified as Streptomyces alboflavus, based on morphology, physiological and biochemical characteristics, and 16S rDNA sequence analysis. RPS lysed 95% of P. globosa within 48 h by releasing an extracellular active substance into the growth medium. The activity of RPS supernatant was sensitive to temperature at and above 50 °C and insensitive to pH from 3 to 11. The molecular weight of the active substance was between 100 Da and 1000 Da, and approximately 90% of it was extracted by ethyl acetate. It was presumed that the active component efficiently inhibited the movement of P. globosa, caused the flagella to fall off the algae, and finally lysed the algal cells. RPS showed a wide target range against harmful algae. S. alboflavus RPS with high algicidal activity and such novel features of temperature and pH sensitivity, low molecular weight, algicidal process, and target range possesses great potential in the biological control of P. globosa blooms. PMID:24675867

Zhang, Bangzhou; Cai, Guanjing; Wang, Haitao; Li, Dong; Yang, Xujun; An, Xinli; Zheng, Xiaowei; Tian, Yun; Zheng, Wei; Zheng, Tianling

2014-01-01

120

Satellite Remote Sensing of Harmful Algal Blooms at the University of Miami Center for Oceans and Human Health  

NASA Astrophysics Data System (ADS)

As part of the NSF-NIEHS Center for Oceans and Human Health at the University of Miami, research is being conducted into the remote sensing of ocean color signatures associated with the occurrence of Harmful Algal Blooms (HABs). Data from the MODerate-resolution Imaging Spectroradiometer (MODIS) are down-linked at the University of Miami's Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) and processed in near-real time to produce mapped fields of water leaving radiance in the ocean color bands, derived quantities including inherent optical properties (IOPs) of seawater, chlorophyll concentration, and sea-surface temperature. Images of these fields are available in near-real time on a web-server. The server also provides access to the data files themselves. One of the applications currently being researched using these data is the identification of HABs over the Central West Florida Shelf where blooms of the toxic dinoflagellate Karenia brevis have a nearly annual occurance. Since chlorophyll concentration alone cannot be used as a unique variable to determine algal taxonomy, other spectral features or optical properties must be brought into play to discriminate among different phytoplankton types. A published technique developed for SeaWiFS (Sea-viewing Wide Field-of-view Sensor) to detect K. brevis (based on high concentration of chlorophyll and low particulate backscatter) was transitioned to measurements of Terra MODIS and replicated the results. These were confirmed by comparisons with in situ measurements. This technique is currently being applied to a multi-year time series of remote measurements from the Aqua MODIS and tested against ship-based data.

Minnett, P. J.; Carvalho, G.; Baringer, W.; Banzon, V.

2007-05-01

121

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

122

Subtle biological responses to increased CO2 concentrations by Phaeocystis globosa Scherffel, a harmful algal bloom species  

NASA Astrophysics Data System (ADS)

Recent investigations into the role of carbon dioxide on phytoplankton growth and composition have clearly shown differential effects among species and assemblages, suggesting that increases in oceanic CO2 may play a critical role in structuring lower trophic levels of marine systems in the future. Furthermore, alarming increases in the occurrence of harmful algal blooms (HABs) in coastal waters have been observed, and while not uniform among systems, appear in some manner to be linked to human impacts (eutrophication) on coastal systems. Models of HABs are in their infancy and do not at present include sophisticated biological effects or their environmental controls. Here we show that subtle biological responses occur in the HAB species Phaeocystis globosa Scherffel as a result of CO2 enrichment induced by gentle bubbling. The alga, which has a polymorphic life history involving the formation of both colonies and solitary cells, exhibited altered growth rates of colonial and solitary forms at [CO2] of 750 ppm, as well as increased colony formation. In addition, substantial modifications of elemental and photosynthetic constituents of the cells (C cell-1, N cell-1, potential quantum yield, chl a cell-1) occurred under elevated CO2 concentrations compared to those found at present CO2 levels. In contrast, other individual and population variables (e.g., colony diameter, total chlorophyll concentration, carbon/nitrogen ratio) were unaffected by increased CO2. Our results suggest that predictions of the future impacts of Phaeocystis blooms on coastal ecosystems and local biogeochemistry need to carefully examine the subtle biological responses of this alga in addition to community and ecosystem effects.

Wang, Yan; Smith, Walker O.; Wang, Xiaodong; Li, Shaoshan

2010-05-01

123

Development of Hyperspectral Remote Sensing Capability For the Early Detection and Monitoring of Harmful Algal Blooms (HABs) in the Great Lakes  

NASA Technical Reports Server (NTRS)

Hyperspectral imagers have significant capability for detecting and classifying waterborne constituents. One particularly appropriate application of such instruments in the Great Lakes is to detect and monitor the development of potentially Harmful Algal Blooms (HABs). Two generations of small hyperspectral imagers have been built and tested for aircraft based monitoring of harmful algal blooms. In this paper a discussion of the two instruments as well as field studies conducted using these instruments will be presented. During the second field study, in situ reflectance data was obtained from the Research Vessel Lake Guardian in conjunction with reflectance data obtained with the hyperspectral imager from overflights of the same locations. A comparison of these two data sets shows that the airborne hyperspectral imager closely matches measurements obtained from instruments on the lake surface and thus positively supports its utilization for detecting and monitoring HABs.

Lekki, John; Anderson, Robert; Nguyen, Quang-Viet; Demers, James; Leshkevich, George; Flatico, Joseph; Kojima, Jun

2013-01-01

124

Tracing the early development of harmful algal blooms on the West Florida Shelf with the aid of Lagrangian coherent structures  

NASA Astrophysics Data System (ADS)

Several theories have been proposed to explain the development of harmful algal blooms (HABs) produced by the toxic dinoflagellate Karenia brevis on the West Florida Shelf. However, because the early stages of HAB development are usually not detected, these theories have been so far very difficult to verify. In this paper we employ simulated Lagrangian coherent structures (LCSs) to trace potential early locations of the development of a HAB in late 2004 before it was transported to a region where it could be detected by satellite imagery. The LCSs, which are extracted from surface ocean currents produced by a data-assimilative HYCOM (HYbrid-Coordinate Ocean Model) simulation, constitute material fluid barriers that demarcate potential pathways for HAB evolution. Using a simplified population dynamics model we infer the factors that could possibly lead to the development of the HAB in question. The population dynamics model determines nitrogen in two components, nutrients and phytoplankton, which are assumed to be passively advected by surface ocean currents produced by the above HYCOM simulation. Two nutrient sources are inferred for the HAB whose evolution is found to be strongly tied to the simulated LCSs. These nutrient sources are found to be located nearshore and possibly due to land runoff.

Olascoaga, M. J.; Beron-Vera, F. J.; Brand, L. E.; KoçAk, H.

2008-12-01

125

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

126

Trophic cascades and future harmful algal blooms within ice-free Arctic Seas north of Bering Strait: A simulation analysis  

NASA Astrophysics Data System (ADS)

Within larger ice-free regions of the western Arctic Seas, subject to ongoing trophic cascades induced by past overfishing, as well as to possible future eutrophication of the drainage basins of the Yukon and Mackenzie Rivers, prior very toxic harmful algal blooms (HABs) - first associated with ?100 human deaths near Sitka, Alaska in 1799 - may soon expand. Blooms of calcareous coccolithophores in the Bering Sea during 1997-1998 were non-toxic harbingers of the subsequent increments of other non-siliceous phytoplankton. But, now saxitoxic dinoflagellates, e.g. Alexandrium tamarense, were instead found by us within the adjacent downstream Chukchi Sea during SBI cruises of 2002 and 2003. A previous complex, coupled biophysical model had been validated earlier by ship-board observations from the Chukchi/Beaufort Seas during the summer of 2002. With inclusion of phosphorus as another chemical state variable to modulate additional competition by recently observed nitrogen-fixers, we now explore here the possible consequences of altered composition of dominant phytoplankton functional groups [diatoms, microflagellates, prymnesiophyte Phaeocystis colonies, coccolithophores, diazotrophs, and dinoflagellates] in relation to increases of the toxic A. tamarense, responding to relaxation of grazing pressure by herbivores north of Bering Strait as part of a continuing trophic cascade. Model formulation was guided by validation observations obtained during 2002-2004 from: cruises of the SBI, CHINARE, and CASES programs; moored arrays in Bering Strait; other RUSALCA cruises around Wrangel Island; and SBI helicopter surveys of the shelf-break regions of the Arctic basin. Our year-long model scenarios during 2002-2003 indicate that post bloom silica-limitation of diatoms, after smaller simulated spring grazing losses, led to subsequent competitive advantages in summer for the coccolithophores, dinoflagellates, and diazotrophs. Immediate top-down control is exerted by imposed grazing pressures of the model’s herbivores and bottom-up control is also effected by light-, nitrate-, ammonium-, silicate-, and phosphate-modulated competition among the six functional groups of the simulated phytoplankton community. Similar to the history of the southern North Sea adjacent to the Rhine River, possible farming of northwestern Alaska and Canada, in conjunction with other human activities of ice retreat and overfishing, may lead to future exacerbations of poisonous phytoplankton. These potential killers include both toxic dinoflagellate and diazotroph HABs, deadly to terrestrial and marine mammals, as well as those of prymnesiophytes, some of which have already foamed beaches, while others have killed fishes of European waters.

Walsh, John J.; Dieterle, Dwight A.; Chen, F. Robert; Lenes, Jason M.; Maslowski, Wieslaw; Cassano, John J.; Whitledge, Terry E.; Stockwell, Dean; Flint, Mikhail; Sukhanova, Irina N.; Christensen, John

2011-11-01

127

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.

128

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

2003-01-01

129

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

130

Development of coastal upwelling edge detection algorithms associated with harmful algal blooms off the Washington coast using sea surface temperature imagery.  

SciTech Connect

Satellite remote sensing imagery is being used to identify and characterize upwelling conditions on the coast of Washington State, with an emphasis on detecting ocean features associated with harmful algal bloom events. Blooms of phytoplankton, including the domoic acid-producing diatom Pseudo-nitzschia, appear to be associated with a semi-permanent eddy bordering Washington and British Columbia that is observed in satellite imagery during extended upwelling events. Strong upwelling conditions may act as a barrier to movement of these blooms onshore. Using NOAA AVHRR temperature imagery, edge detection algorithms are being developed to define the strength, location and extent of the surface temperature expression of upwelling along the coast of Washington. The edge detection technique uses a simple kernel-based gradient method that compares temperatures of pixels at a user-specified distance. This allows identification of larger features with subtle edges. The resulting maximum-gradient map is then converted to a binary format with a user-specified temperature threshold. Skeletonization and edge-linking algorithms are then employed to develop final map products. The upwelling edge detection maps are being examined in relation to harmful algal bloom events that have occurred along the coast.

Evans, Nathan R.; Woodruff, Dana L.; Trainer, Vera L.

2005-01-01

131

Algal Bloom Detection from HICO  

NASA Astrophysics Data System (ADS)

Ocean color satellites provide daily, global views of marine bio-optical properties in the upper ocean at various spatial scales. The most productive area of the global ocean is the coastal zone which is heavily impacted by urban and agricultural runoff, transportation, recreation, and oil and gas production. In recent years, harmful algal blooms (HABs) have become one of the serious environmental problems in the coastal areas on a global scale. The global nature of the problem has expanded in its frequency, severity, and extent over the last several decades. Human activities and population increases have contributed to an increase in various toxic and noxious algal species in the coastal regions worldwide. Eutrophication in estuaries and coastal waters is believed to be the major factor causing HABs. In this study, we assess the applicability of the Red Band Difference (RBD) HAB detection algorithm on data from the Hyperspectral Imager for the Coastal Ocean (HICO). Our preliminary results show that due to various uncertainties such as atmospheric correction, calibration and possibly also the relatively low signal-to-noise ratio of HICO for fluorescence detection, it is difficult to extract the fluorescence portion of the reflectance spectrum that RBD uses for bloom detection. We propose an improved bloom detection technique for HICO using red and NIR bands. Our results are validated using other space-borne and ground based measurements.

Amin, Ruhul; Gould, Richard

2014-05-01

132

Genetic Variation of the Bloom-Forming Cyanobacterium Microcystis aeruginosa within and among Lakes: Implications for Harmful Algal Blooms  

PubMed Central

To measure genetic variation within and among populations of the bloom-forming cyanobacterium Microcystis aeruginosa, we surveyed a suite of lakes in the southern peninsula of Michigan that vary in productivity (total phosphorus concentrations of ?10 to 100 ?g liter?1). Survival of M. aeruginosa isolates from lakes was relatively low (i.e., mean of 7% and maximum of 30%) and positively related to lake total phosphorus concentration (P = 0.014, r2 = 0.407, n = 14). In another study (D. F. Raikow, O. Sarnelle, A. E. Wilson, and S. K. Hamilton, Limnol. Oceanogr. 49:482-487, 2004), survival rates of M. aeruginosa isolates collected from an oligotrophic lake (total phosphorus of ?10 ?g liter?1 and dissolved inorganic nitrogen:total phosphorus ratio of 12.75) differed among five different medium types (G test, P of <0.001), with higher survival (P = 0.003) in low-nutrient media (28 to 37% survival) than in high-nutrient media. Even with the relatively low isolate survivorship that could select against detecting the full range of genetic variation, populations of M. aeruginosa were genetically diverse within and among lakes (by analysis of molecular variance, ?sc = 0.412 [?sc is an F-statistic derivative which evaluates the correlation of haplotypic diversity within populations relative to the haplotypic diversity among all sampled populations], P = 0.001), with most clones being distantly related to clones collected from lakes directly attached to Lake Michigan (a Laurentian Great Lake) and culture collection strains collected from Canada, Scotland, and South Africa. Ninety-one percent of the 53 genetically unique M. aeruginosa clones contained the microcystin toxin gene (mcyA). Genotypes with the toxin gene were found in all lakes, while four lakes harbored both genotypes possessing and genotypes lacking the toxin gene.

Wilson, Alan E.; Sarnelle, Orlando; Neilan, Brett A.; Salmon, Tim P.; Gehringer, Michelle M.; Hay, Mark E.

2005-01-01

133

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

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, C; Bowman, J P; Hallegraeff, G M

1998-08-01

134

Harmful Algal Blooms (HABs)  

MedlinePLUS

... About CDC.gov . Promoting Clean Water for Health Facebook Recommend Twitter Tweet Share Compartir Add this to... ... is difficult. Red tides occur throughout the world, affecting marine ecosystems in Scandinavia, Japan, the Caribbean, and ...

135

The risk of harmful algal blooms (HABs) in the oyster-growing estuaries of New South Wales, Australia.  

PubMed

The spatial and temporal variability of potentially harmful phytoplankton was examined in the oyster-growing estuaries of New South Wales. Forty-five taxa from 31 estuaries were identified from 2005 to 2009. Harmful species richness was latitudinally graded for rivers, with increasing number of taxa southward. There were significant differences (within an estuary) in harmful species abundance and richness for 11 of 21 estuaries tested. Where differences were observed, these were predominately due to species belonging to the Pseudo-nitzschia delicatissima group, Dinophysis acuminata, Dictyocha octonaria and Prorocentrum cordatum with a consistent upstream versus downstream pattern emerging. Temporal (seasonal or interannual) patterns in harmful phytoplankton within and among estuaries were highly variable. Examination of harmful phytoplankton in relation to recognised estuary disturbance measures revealed species abundance correlated to estuary modification levels and flushing time, with modified, slow flushing estuaries having higher abundance. Harmful species richness correlated with bioregion, estuary modification levels and estuary class, with southern, unmodified lakes demonstrating greater species density. Predicting how these risk taxa and risk zones may change with further estuary disturbance and projected climate warming will require more focused, smaller scale studies aimed at a deeper understanding of species-specific ecology and bloom mechanisms. Coupled with this consideration, there is an imperative for further taxonomic, ecological and toxicological investigations into poorly understood taxa (e.g. Pseudo-nitzschia). PMID:23111868

Ajani, Penelope; Brett, Steve; Krogh, Martin; Scanes, Peter; Webster, Grant; Armand, Leanne

2013-06-01

136

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

137

Nutrients, phytoplankton and harmful algal blooms in shrimp ponds: a review with special reference to the situation in the Gulf of California  

Microsoft Academic Search

The present work is a first attempt to document the latest reports on the occurrence of algal blooms in shrimp farm ponds worldwide. Particular emphasis is placed on discussing the relation of algal blooms with nutrients, with special reference to the northwest of Mexico. Typically, shrimp pond waters are enriched with organic matter and nutrients whose concentrations depend mostly on

R Alonso-Rodr??guez; F Páez-Osuna

2003-01-01

138

Effect of okadaic acid on carpet shell clam (Ruditapes decussatus) haemocytes by in vitro exposure and harmful algal bloom simulation assays.  

PubMed

Okadaic acid (OA), produced by dinoflagellates during harmful algal blooms (HAB), belongs to the Diarrheic Shellfish Poisoning toxins that cause gastrointestinal symptoms in humans after consumption. In the present work, Ruditapes decussatus haemocytes were selected to evaluate the effect of OA on cell viability, enzymatic status and immune capacity through the measure by flow cytometry of apoptosis-cell death, non-specific esterase activity and phagocytosis. In order to compare different exposure conditions, two experiments were developed: in vitro exposure to OA and HAB simulation by feeding clams with the OA producer, Prorocentrum lima. Apoptosis was not OA dose-dependent and cell death increased in both assays. Phagocytosis of latex beads and esterase activity decreased in haemocytes incubated with OA. In contrast, esterases increased during the feeding with P. lima. Our results showed that OA and the simulated HAB caused damages on haemocyte functions and viability. PMID:23657590

Prado-Alvarez, Maria; Flórez-Barrós, Fernanda; Méndez, Josefina; Fernandez-Tajes, Juan

2013-06-01

139

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

140

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.

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

2010-01-01

141

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

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 × 10(4) 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

2011-01-17

142

Development of Hyperspectral Remote Sensing Capability For the Early Detection and Monitoring of Harmful Algal Blooms (HABs) in the Great Lakes.  

National Technical Information Service (NTIS)

Hyperspectral imagers have significant capability for detecting and classifying waterborne constituents. One particularly appropriate application of such instruments in the Great Lakes is to detect and monitor the development of potentially Harmful Algal ...

G. Leshkevich J. Demers J. Flatico J. Kojima J. Lekki Q. V. Nguyen R. Anderson

2013-01-01

143

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

144

Linking the physiology and ecology of Cochlodinium to better understand harmful algal bloom events: A comparative approach  

Microsoft Academic Search

The red tide forming dinoflagellate genus Cochlodinium appears to be expanding globally, as well as blooming and\\/or causing more economic losses within its previously reported geographic distribution. Despite the widespread occurrence of this organism in the Pacific, Atlantic, and Indian oceans, relatively few studies of its ecophysiology have been conducted. Here we summarize the ecophysiological characteristics through both a literature

Raphael M. Kudela; John P. Ryan; Melissa D. Blakely; Tawnya D. Peterson

2008-01-01

145

Turbulence, watermass stratification and harmful algal blooms: an alternative view and frontal zones as “pelagic seed banks”  

Microsoft Academic Search

Watermass stratification has been considered the essential physical condition that dinoflagellates require to bloom because of their relative inability, unlike diatoms, to tolerate the elevated shear-stress associated with water-column mixing, turbulence and high velocity, coastal currents. The swimming speeds of 71 flagellate taxa, with a focus on dinoflagellates, are compared to the turbulence fields and vertical velocities that develop during

Theodore J Smayda

2002-01-01

146

Isolation and characterization of exopolysaccharide secreted by a toxic dinoflagellate, Amphidinium carterae Hulburt 1957 and its probable role in harmful algal blooms (HABs).  

PubMed

Extracellular polymeric substances (EPS) produced by a toxic dinoflagellate Amphidinium carterae Hulburt 1957 was isolated and characterized. Molecular masses of the EPS were about 233 and 1,354 kDa. Spectral analyses by (1)H nuclear magnetic resonance and Fourier Transformed-Infrared Spectroscopy revealed the characteristic of the functional groups viz. primary amine, carboxyl, halide, and sulfate groups present in the EPS. However, five elements (C, O, Na, S, and Ca) were detected by scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM-EDX) analysis. X-ray diffraction and differential scanning calorimetric analysis confirmed the amorphous nature of EPS, which was comprised of an average particle size of 13.969 ?m (d 0.5) with 181 nm average roughness. Two monosaccharide constituents, galactose (73.13%) and glucose (26.87%) were detected by gas chromatography-mass spectroscopy analysis. Thermal gravimetric analysis revealed that degradation of EPS obtained from A. carterae takes place in three steps. The EPS produced by A. carterae was found to be beneficial for the growth of both A. carterae and Bacillus pumilus. The potential heterogeneous properties of EPS may play an important role in harmful algal bloom. PMID:21503775

Mandal, Subir Kumar; Singh, Ravindra Pal; Patel, Vipul

2011-10-01

147

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

148

Spatial patterns in dense algal blooms  

Microsoft Academic Search

lntricatc and striking patterns are often created in dense algal blooms by the interaction of sinking, floating, or swllmming algae and local physical dynamics. The structure of these patterns can reveal a great deal about the processes underlying the pattern formation. Here I explore three common patterns in dense algal blooms: chaotic mixing, internal wave banding, and sharp fronts. For

Peter J. S. Franks

1997-01-01

149

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

150

Genetic programming for analysis and real-time prediction of coastal algal blooms  

Microsoft Academic Search

Harmful algal blooms (HAB) have been widely reported and have become a serious environmental problem world wide due to its negative impacts to aquatic ecosystems, fisheries, and human health. A capability to predict the occurrence of algal blooms with an acceptable accuracy and lead-time would clearly be very beneficial to fisheries and environmental management. In this study, we present the

Nitin Muttil; Joseph H. W. Lee

2005-01-01

151

A simple model for forecast of coastal algal blooms  

NASA Astrophysics Data System (ADS)

In eutrophic sub-tropical coastal waters around Hong Kong and South China, algal blooms (more often called red tides) due to the rapid growth of microscopic phytoplankton are often observed. Under favourable environmental conditions, these blooms can occur and subside over rather short time scales—in the order of days to a few weeks. Very often, these blooms are observed in weakly flushed coastal waters under calm wind conditions—with or without stratification. Based on high-frequency field observations of harmful algal blooms at two coastal mariculture zones in Hong Kong, a mathematical model has been developed to forecast algal blooms. The model accounts for algal growth, decay, settling and vertical turbulent mixing, and adopts the same assumptions as the classical Riley, Stommel and Bumpus model (Riley, G.A., Stommel, H., Bumpus, D.F., 1949. Quantitative ecology of the plankton of the western North Atlantic. Bulletin of the Bingham Oceanographic Collection Yale University 12, 1-169). It is shown that for algal blooms to occur, a vertical stability criterion, E < 4 ?l2/ ?2, must be satisfied, where E, ?, l are the vertical turbulent diffusivity, algal growth rate, and euphotic layer depth respectively. In addition, a minimum nutrient threshold concentration must be reached. Moreover, with a nutrient competition consideration, the type of bloom (caused by motile or non-motile species) can be classified. The model requires as input simple and readily available field measurements of water column transparency and nutrient concentration, and representative maximum algal growth rate of the motile and non-motile species. In addition, with the use of three-dimensional hydrodynamic circulation models, simple relations are derived to estimate the vertical mixing coefficient as a function of tidal range, wind speed, and density stratification. The model gives a quick assessment of the likelihood of algal bloom occurrence, and has been validated against field observations over a 4-year period. The model helps to explain the observed spatial and temporal patterns of bloom occurrences in relation to the vertical turbulence and nutrient condition. The success of the model points the way to the development of real time management models for disaster mitigation.

Wong, Ken T. M.; Lee, Joseph H. W.; Hodgkiss, I. J.

2007-08-01

152

Screening of Various Herbicide Modes of Action for Selective Control of Algae Responsible for Harmful Blooms.  

National Technical Information Service (NTIS)

This research seeks to identify reduced risk chemical compounds that have selective activity against harmful algal blooms (HAB). The U.S. Army Corps of Engineers is responsible for managing numerous large reservoirs throughout the country, and the recent ...

A. G. Poovey C. A. Lembi M. D. Netherland

2009-01-01

153

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

154

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

155

MULTISENSOR SYNERGY FOR MONITORING OF ALGAL BLOOMS IN THE NORTH SEA  

Microsoft Academic Search

The operational service for algal bloom monitoring at NERSC is primarily based on NOAA AVHRR and SeaWiFS optical data. The service has shown very useful in several occasions since 1998 while severe and harmful blooms of the algae Chattonella sp. were reported from the North Sea off the coast of Denmark. Early detection and mapping of the extent and concentrations

Birgitte R. Furevik; Dominique Durand; Lasse Pettersson

2005-01-01

156

Le fioriture di alghe tossiche nelle acque dolci: emergenza sanitaria e misure di controllo. Istituto Superiore di Sanita (Freshwater Harmful Algal Blooms: Health Risk and Control Management. Istituto Superiore di Sanita).  

National Technical Information Service (NTIS)

During the last thirty years the consequences of the 'green house effect' and the excessive nutrient input in waters have been determining a worldwide increase in algal blooms, often toxin producers, even in freshwater basins destined for drinkable uses. ...

S. Melchiorre W. Viaggiu M. Bruno

2002-01-01

157

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

158

Neural network modelling of coastal algal blooms  

Microsoft Academic Search

An artificial neural network (ANN), a data driven modelling approach, is proposed to predict the algal bloom dynamics of the coastal waters of Hong Kong. The commonly used back-propagation learning algorithm is employed for training the ANN. The modeling is based on (a) comprehensive biweekly water quality data at Tolo Harbour (1982–2000); and (b) 4-year set of weekly phytoplankton abundance

Joseph H. W. Lee; Yan Huang; Mike Dickman; A. W. Jayawardena

2003-01-01

159

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

160

Evaluation of the use of SeaWiFS imagery for detecting Karenia brevis harmful algal blooms in the eastern Gulf of Mexico  

Microsoft Academic Search

Frequent blooms of the toxic dinoflagellate, Karenia brevis, along the west coast of Florida are of considerable concern to state resource managers due to numerous ecological and health impacts. With the availability of remotely sensed ocean color imagery from SeaWiFS, a regional algorithm that compensates for the scattering of sediments in coastal waters can be applied to accurately estimate chlorophyll

Michelle C Tomlinson; Richard P Stumpf; Varis Ransibrahmanakul; Earnest W Truby; Gary J Kirkpatrick; Bradley A Pederson; Gabriel A Vargo; Cynthia A Heil

2004-01-01

161

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

162

Neural network and genetic programming for modelling coastal algal blooms  

Microsoft Academic Search

In the recent past, machine learning (ML) techniques such as artificial neural networks (ANN) have been increasingly used to model algal bloom dynamics. In the present paper, along with ANN, we select genetic programming (GP) for modelling and prediction of algal blooms in Tolo Harbour, Hong Kong. The study of the weights of the trained ANN and also the GP-evolved

Nitin Muttil; Kwok-wing Chau

2006-01-01

163

A simple model for forecast of coastal algal blooms  

Microsoft Academic Search

In eutrophic sub-tropical coastal waters around Hong Kong and South China, algal blooms (more often called red tides) due to the rapid growth of microscopic phytoplankton are often observed. Under favourable environmental conditions, these blooms can occur and subside over rather short time scales—in the order of days to a few weeks. Very often, these blooms are observed in weakly

Ken T. M. Wong; Joseph H. W. Lee; I. J. Hodgkiss

2007-01-01

164

A simple model for forecast of coastal algal blooms  

Microsoft Academic Search

In eutrophic sub-tropical coastal waters around Hong Kong and South China, algal blooms (more often called red tides) due to the rapid growth of microscopic phytoplankton are often observed. Under favourable environmental conditions, these blooms can occur and subside over rather short time scales---in the order of days to a few weeks. Very often, these blooms are observed in weakly

Ken T. M. Wong; Joseph H. W. Lee; I. J. Hodgkiss

2007-01-01

165

The Harmful Algae Page  

NSDL National Science Digital Library

Relevant sections in this resource include What are Harmful Algal Blooms (HABs), an Introduction to Algal Blooms and "Red Tide", Algae Species (which algae are responsible for the harmful effects?), Adverse Impacts, Human Illness (food poisoning associated with harmful algal blooms & information on diagnosis and treatment), HAB Distribution Maps, HAB events in the United States and around the world, HAB related articles as printed in the news media, and a photo gallery of visible algal blooms, photomicrographs, and satellite imagery.

Anderson, Donald

2004-06-17

166

Skill assessment for an operational algal bloom forecast system  

NASA Astrophysics Data System (ADS)

An operational forecast system for harmful algal blooms (HABs) in southwest Florida is analyzed for forecasting skill. The HABs, caused by the toxic dinoflagellate, Karenia brevis, lead to shellfish toxicity and to respiratory irritation. In addition to predicting new blooms and their extent, HAB forecasts are made twice weekly during a bloom event, using a combination of satellite derived image products, wind predictions, and a rule-based model derived from previous observations and research. These forecasts include: identification, intensification, transport, extent, and impact; the latter being the most significant to the public. Identification involves identifying new blooms as HABs and is validated against an operational monitoring program involving water sampling. Intensification forecasts, which are much less frequently made, can only be evaluated with satellite data on mono-specific blooms. Extent and transport forecasts of HABs are also evaluated against the water samples. Due to the resolution of the forecasts and available validation data, skill cannot be resolved at scales finer than 30 km. Initially, respiratory irritation forecasts were analyzed using anecdotal information, the only available data, which had a bias toward major respiratory events leading to a forecast accuracy exceeding 90%. When a systematic program of twice-daily observations from lifeguards was implemented, the forecast could be meaningfully assessed. The results show that the forecasts identify the occurrence of respiratory events at all lifeguard beaches 70% of the time. However, a high rate (80%) of false positive forecasts occurred at any given beach. As the forecasts were made at half to whole county level, the resolution of the validation data was reduced to county level, reducing false positives to 22% (accuracy of 78%). The study indicates the importance of systematic sampling, even when using qualitative descriptors, the use of validation resolution to evaluate forecast capabilities, and the need to match forecast and validation resolutions.

Stumpf, Richard P.; Tomlinson, Michelle C.; Calkins, Julie A.; Kirkpatrick, Barbara; Fisher, Kathleen; Nierenberg, Kate; Currier, Robert; Wynne, Timothy T.

2009-02-01

167

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.

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

2008-01-01

168

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.

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

169

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.

170

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

171

Application of an Algal Bloom Model (Bloom II) to Combat Eutrophication.  

National Technical Information Service (NTIS)

The phytoplankton model BLOOM II is an extended and modified version of the Algal Bloom Model developed by the Rand Corp. for the saltwater basin of the Oosterschelde. The present freshwater version has been developed during the last two and a half years ...

F. J. Los

1980-01-01

172

MODIS Detects a Devastating Algal Bloom in Paracas Bay, Peru  

Microsoft Academic Search

The medium-resolution bands on NASA's Moderate-Resolution Imaging Spectroradiometer (MODIS) were successfully used to detect and map the distribution of a harmful phytoplankton bloom in the Paracas Bay, Peru, that caused economic losses worth millions of dollars. Routine application of MODIS data can be a valuable and cost-effective way to monitor harmful blooms and other turbid water plumes that cause disruption

Mati Kahru; B. Greg Mitchell; Anibal Diaz; Manuel Miura

2004-01-01

173

Prediction of algal blooming using EFDC model: Case study in the Daoxiang Lake  

Microsoft Academic Search

Algal blooming has become one of the key fields of study on eutrophication of water body recently. The mechanism of algal blooming is still not understood well. However, it is obvious to understand that algal blooming has close relationship with chlorophyll-a. Therefore, if the trends of chlorophyll-a concentration can be simulated accurately, it will be helpful for the prediction of

Guozheng Wu; Zongxue Xu

2011-01-01

174

Relating Algal Bloom Frequencies to Phosphorus Concentrations in Lake Okeechobee  

Microsoft Academic Search

Empirical relationships were developed between algal bloom frequencies and total phosphorus concentrations for three distinct regions of Lake Okeechobee, and hypotheses were derived to explain observed spatial variation in those relationships. The analyses were based on water quality monitoring data collected monthly between 1986 and 1993, at 10 open-water stations, 12 north littoral stations, and 14 south littoral stations. Using

William W. Walker Jr; Karl E. Havens

1995-01-01

175

Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers  

NASA Astrophysics Data System (ADS)

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.

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

2011-05-01

176

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

PubMed Central

In 2011, Lake Erie experienced the largest harmful algal bloom in its recorded history, with a peak intensity over three times greater than any previously observed bloom. Here we show that long-term trends in agricultural practices are consistent with increasing phosphorus loading to the western basin of the lake, and that these trends, coupled with meteorological conditions in spring 2011, produced record-breaking nutrient loads. An extended period of weak lake circulation then led to abnormally long residence times that incubated the bloom, and warm and quiescent conditions after bloom onset allowed algae to remain near the top of the water column and prevented flushing of nutrients from the system. We further find that all of these factors are consistent with expected future conditions. If a scientifically guided management plan to mitigate these impacts is not implemented, we can therefore expect this bloom to be a harbinger of future blooms in Lake Erie.

Michalak, Anna M.; Anderson, Eric J.; Beletsky, Dmitry; Boland, Steven; Bosch, Nathan S.; Bridgeman, Thomas B.; Chaffin, Justin D.; Cho, Kyunghwa; Confesor, Rem; Daloglu, Irem; DePinto, Joseph V.; Evans, Mary Anne; Fahnenstiel, Gary L.; He, Lingli; Ho, Jeff C.; Jenkins, Liza; Johengen, Thomas H.; Kuo, Kevin C.; LaPorte, Elizabeth; Liu, Xiaojian; McWilliams, Michael R.; Moore, Michael R.; Posselt, Derek J.; Richards, R. Peter; Scavia, Donald; Steiner, Allison L.; Verhamme, Ed; Wright, David M.; Zagorski, Melissa A.

2013-01-01

177

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

PubMed

In 2011, Lake Erie experienced the largest harmful algal bloom in its recorded history, with a peak intensity over three times greater than any previously observed bloom. Here we show that long-term trends in agricultural practices are consistent with increasing phosphorus loading to the western basin of the lake, and that these trends, coupled with meteorological conditions in spring 2011, produced record-breaking nutrient loads. An extended period of weak lake circulation then led to abnormally long residence times that incubated the bloom, and warm and quiescent conditions after bloom onset allowed algae to remain near the top of the water column and prevented flushing of nutrients from the system. We further find that all of these factors are consistent with expected future conditions. If a scientifically guided management plan to mitigate these impacts is not implemented, we can therefore expect this bloom to be a harbinger of future blooms in Lake Erie. PMID:23576718

Michalak, Anna M; Anderson, Eric J; Beletsky, Dmitry; Boland, Steven; Bosch, Nathan S; Bridgeman, Thomas B; Chaffin, Justin D; Cho, Kyunghwa; Confesor, Rem; Daloglu, Irem; Depinto, Joseph V; Evans, Mary Anne; Fahnenstiel, Gary L; He, Lingli; Ho, Jeff C; Jenkins, Liza; Johengen, Thomas H; Kuo, Kevin C; Laporte, Elizabeth; Liu, Xiaojian; McWilliams, Michael R; Moore, Michael R; Posselt, Derek J; Richards, R Peter; Scavia, Donald; Steiner, Allison L; Verhamme, Ed; Wright, David M; Zagorski, Melissa A

2013-04-16

178

Connecting Florida Bay algal blooms to freshwater nutrient sources  

NASA Astrophysics Data System (ADS)

In this study, monthly water quality data collected in the Everglades by the Southeast Environmental Research Center (SERC) and the South Florida Water Management District (SFWMD) from 1991 to 2008 at 28 sampling stations distributed across Florida Bay was analyzed within the context of local geomorphology and seasonal wind and current regimes in order to evaluate the feasibility of the various purported nutrient sources for reoccurring algal blooms. The in situ chlorophyll-a (chl-a) measurements from the SERC dataset were evaluated as the indicator of algal biomass. Significant differences in average monthly chl-a concentrations at stations indicated a seasonality of algal blooms in the north central and west areas that is not evidenced in stations exhibiting low levels of chl-a throughout the typical year. Tukey's pairwise comparisons of monthly chl-a indicated, at the 95% confidence level, peak algal biomass occurs in October and November at the end of the wet season with minimums occurring between February and August depending on the location of the station. By month comparison of chl-a levels across stations suggest seasonal trends in the geographic focus and extent of blooms. Significant differences from Tukey's pairwise comparisons at the 95% confidence level showed stations to the west as having higher levels of chl-a in March through May with north central stations dominating from June to January. The month of February shows no significant difference in chl-a levels across this area. The results support hypotheses centering on a western source of nutrients that are delivered to the bay over the course of the rainy season. Mapping water quality sampling station locations on top of the bathymetry of Florida Bay illustrates the importance of considering coastal morphology in explaining trends in estuarine algal blooms. Coastal geomorphology along with seasonal changes in the direction of winds and magnitude of rains are demonstrated to be the predominant factors influencing the nutrient circulation that is pertinent to observed patterns in Florida Bay algal blooms. These results point to the utility of regional hydrogeologic characterizations at fine spatial and temporal resolutions in tracking seasonally variable hydrologic inputs in complex and dynamic systems.

Blakey, T.; Melesse, A. M.

2013-12-01

179

Effect of algal bloom deposition on sediment respiration and fluxes  

Microsoft Academic Search

Using sediment cores collected in November 1989 from Aarhus Bight, Denmark, the fluxes of O2, SCO2 (total CO2), NH4+, NO3-+NO2-and DON (dissolved organic nitrogen) across the sediment-water interface were followed for 20 d in an experimental continous flow system. On day 7, phytoplankton was added to the sediment surface, to see the result of simulated algal bloom sedimentation. Benthic O2

L. S. Hansen; T. H. Blackburn

1992-01-01

180

The extended Kalman filter for forecast of algal bloom dynamics.  

PubMed

A deterministic ecosystem model is combined with an extended Kalman filter (EKF) to produce short term forecasts of algal bloom and dissolved oxygen dynamics in a marine fish culture zone (FCZ). The weakly flushed FCZ is modelled as a well-mixed system; the tidal exchange with the outer bay is lumped into a flushing rate that is numerically determined from a three-dimensional hydrodynamic model. The ecosystem model incorporates phytoplankton growth kinetics, nutrient uptake, photosynthetic production, nutrient sources from organic fish farm loads, and nutrient exchange with a sediment bed layer. High frequency field observations of chlorophyll, dissolved oxygen (DO) and hydro-meteorological parameters (sampling interval Deltat=1 day, 2h, 1h, respectively) and bi-weekly nutrient data are assimilated into the model to produce the combined state estimate accounting for the uncertainties. In addition to the water quality state variables, the EKF incorporates dynamic estimation of algal growth rate and settling velocity. The effectiveness of the EKF data assimilation is studied for a wide range of sampling intervals and prediction lead-times. The chlorophyll and dissolved oxygen estimated by the EKF are compared with field data of seven algal bloom events observed at Lamma Island, Hong Kong. The results show that the EKF estimate well captures the nonlinear error evolution in time; the chlorophyll level can be satisfactorily predicted by the filtered model estimate with a mean absolute error of around 1-2 microg/L. Predictions with 1-2 day lead-time are highly correlated with the observations (r=0.7-0.9); the correlation stays at a high level for a lead-time of 3 days (r=0.6-0.7). Estimated algal growth and settling rates are in accord with field observations; the more frequent DO data can compensate for less frequent algal biomass measurements. The present study is the first time the EKF is successfully applied to forecast an entire algal bloom cycle, suggesting the possibility of using EKF for real time forecast of algal bloom dynamics. PMID:19577268

Mao, J Q; Lee, Joseph H W; Choi, K W

2009-09-01

181

Detection of algal bloom with in situ and MODIS in Lake TaiHu, China  

NASA Astrophysics Data System (ADS)

In recent years, great amount of polluted water discharged into the north part of Lake TaiHu, results in water eutrophication and frequent occurrences of blue-green algal bloom in the area. In order to obtain the information about blue-green algal bloom distribution for monitoring water quality, four navigation of in situ hyperspectral measurement and MODIS data of 250 m resolution were used to study the radiance reflectance character and distribution of blue-green algal bloom in the lake. Hyperspectral measurement showed that the peak of water leaving radiance near 700 nm transferred to 750-780 nm as the water covered with blue-green algal bloom and increased with the increasing density of water bloom. Band ratio of channel I to channel II and band synthesize of MODIS image of 250 m resolution were used for detection of algal bloom, and proved that band ratio of channel I to channel II was more suitable for detection of algal bloom. The methods for differentiating submerged vegetation and algal bloom from MODIS image were also tested: The area covered with submerged vegetation usually had high secchi depth, with algal bloom usually low secchi depth, and the phenomena can be used efficiently for differentiating submerged vegetation and algal bloom on MODIS image.

Dingtian, Yang; Delu, Pan; Xiaoyu, Zhang; Yan, Bai; Xianqiang, He; Difeng, Wang; Fang, Gong; Shujing, Li

2005-10-01

182

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

183

Parasitic chytrids sustain zooplankton growth during inedible algal bloom  

PubMed Central

This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of “inedible” algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19–20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin.

Rasconi, Serena; Grami, Boutheina; Niquil, Nathalie; Jobard, Marlene; Sime-Ngando, Telesphore

2014-01-01

184

Parasitic chytrids sustain zooplankton growth during inedible algal bloom.  

PubMed

This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of "inedible" algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19-20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin. PMID:24904543

Rasconi, Serena; Grami, Boutheina; Niquil, Nathalie; Jobard, Marlène; Sime-Ngando, Télesphore

2014-01-01

185

Algal bloom-associated disease outbreaks among users of freshwater lakes--United States, 2009-2010.  

PubMed

Harmful algal blooms (HABs) are excessive accumulations of microscopic photosynthesizing aquatic organisms (phytoplankton) that produce biotoxins or otherwise adversely affect humans, animals, and ecosystems. HABs occur sporadically and often produce a visible algal scum on the water. This report summarizes human health data and water sampling results voluntarily reported to CDC's Waterborne Disease and Outbreak Surveillance System (WBDOSS) via the National Outbreak Reporting System (NORS) and the Harmful Algal Bloom-Related Illness Surveillance System (HABISS)* for the years 2009-2010. For 2009-2010, 11 waterborne disease outbreaks associated with algal blooms were reported; these HABs all occurred in freshwater lakes. The outbreaks occurred in three states and affected at least 61 persons. Health effects included dermatologic, gastrointestinal, respiratory, and neurologic signs and symptoms. These 11 HAB-associated outbreaks represented 46% of the 24 outbreaks associated with untreated recreational water reported for 2009-2010, and 79% of the 14 freshwater HAB-associated outbreaks that have been reported to CDC since 1978. Clinicians should be aware of the potential for HAB-associated illness among patients with a history of exposure to freshwater. PMID:24402467

Hilborn, Elizabeth D; Roberts, Virginia A; Backer, Lorraine; Deconno, Erin; Egan, Jessica S; Hyde, James B; Nicholas, David C; Wiegert, Eric J; Billing, Laurie M; Diorio, Mary; Mohr, Marika C; Hardy, Joan F; Wade, Timothy J; Yoder, Jonathan S; Hlavsa, Michele C

2014-01-10

186

Removal of algal blooms from freshwater by the coagulation-magnetic separation method.  

PubMed

This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups. PMID:22767355

Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck

2013-01-01

187

Physical-biological sources for dense algal blooms near the Changjiang River  

NASA Astrophysics Data System (ADS)

Harmful algal blooms (``red tides'') occur primarily in a confined region on the inner shelf off the Changjiang River in the East China Sea during May-August. The areal extent of these blooms has increased dramatically in the last decade, and is thought to be associated with the rapid increase in nutrient supply via the Changjiang River. An interdisciplinary survey conducted in August 2000 identified three areas of high chlorophyll-a concentration in this region: the near-surface Changjiang River plume with high dissolved oxygen and pH, the thermocline above Taiwan Warm Current (TWC) water, and near the bottom north of the Zhoushan Island complex, an area of strong sediment deposition from the Changjiang River with low dissolved oxygen and pH. These results imply that the formation of phytoplankton blooms is controlled by a complex interplay of physical, geological, biological, and chemical processes associated with the Changjiang River discharge, sediment deposition, and TWC intrusions. The predicted increase in nutrient loading in the Changjiang River due to further economic development of Shanghai and reduction in sediment discharge due to the Three Gorges dam suggest that this part of the East China Sea could become an ecosystem disaster, with possible downstream contamination of Korea and Japan, unless the nutrient loading from Shanghai and surrounding cities and aquaculture activities along the coast are reduced.

Chen, Changsheng; Zhu, Jianrong; Beardsley, Robert C.; Franks, Peter J. S.

2003-05-01

188

TRACKING FRESHWATER DIVERSIONS AND ALGAL BLOOMS THAT IMPACT THE NEW ORLEANS STANDARD METROPOLITAN STATISTICAL AREA -  

EPA Science Inventory

This project will monitor selected water quality parameters, including water temperature, turbidity, salinity, and algal blooms to assess the impacts of freshwater diversions for several selected areas within the New Orleans metropolitan area. The specific areas of study include ...

189

Water Quality of Hyrum Lake and Its Relationship to Algal Blooms.  

National Technical Information Service (NTIS)

The relationship between the occurrence of an algal bloom in a northern Utah lake and the corresponding availability of nutrients indicates phosphorous to be the limiting macronutrient. Feedlots surrounding the lake appear to contribute significant quanti...

R. I. Lynn R. B. Murray

1972-01-01

190

Factors Regulating Nuisance Blue-Green Algal Bloom Potentials in the Lower Neuse River, North Carolina.  

National Technical Information Service (NTIS)

Bi-weekly examinations of physical, chemical, and biotic factors involved in the establishment and proliferation of blue-green algal (Microcystis aeruginosa) blooms in the lower Neuse River indicated several causative agents. Included are: excessive conce...

H. W. Paerl

1983-01-01

191

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

192

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

193

Seasonal and Spatial Variation in Algal Bloom Frequencies in Lake Okeechobee, Florida, U.S.A  

Microsoft Academic Search

This study quantified the seasonal and spatial distribution of algal blooms (defined as chlorophyll a >40 ?g L) in Lake Okeechobee, based on 13 years of data collected from eight pelagic monitoring stations by the South Florida Water Management District Relationships between bloom frequencies and limnological parameters, including nutrient (nitrogen and phosphorus) loading rates, in-lake nutrient concentrations, Secchi transparencies, lake

Karl E. Havens; Charles Hanlon; R. Thomas James

1994-01-01

194

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

195

Use of artificial neural network in the prediction of algal blooms  

Microsoft Academic Search

A model to quantify the interactions between abiotic factors and algal genera in Lake Kasumigaura, Japan was developed using artificial neural network technology. Results showed that the timing and magnitude of algal blooms of Microcystis, Phormidium and Synedra in Lake Kasumigaura could be successfully predicted. As for the newly occurring dominant Oscillatoria, results were not satisfactory. The evaluation of the

Bin Wei; Norio Sugiura; Takaaki Maekawa

2001-01-01

196

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

197

Removal of Algal Blooms in Freshwater by Meso-porous Composite Coagulant  

NASA Astrophysics Data System (ADS)

Based on the concept of ``using waste to treat waste and changing waste into valuables'', this paper put forward a new meso-porous composite coagulant with good performance and low cost, and the removal effects of meso-porous composite coagulant on algae cells and toxins, dissolved organics in water was studied, the object of this research was to provide a new and effective way for emergency needs to clear up harmful algal blooms in freshwater. The results showed that meso-porous composite coagulant at optimal loadings (1g/L) could remove over 99% algal cells; meanwhile, the removal efficiency of COD, microcystin, total nitrogen and phosphorus was found to be 87.5%, 97.7%, 41.5% and 77.8% respectively, moreover, the forming speed of floccules was fast, and the dense floccules had good settling performance. Furthermore, the mechanism of algae removal was explored preliminarily by meso-porous composite coagulant which played a dual role in adsorption and flocculation.

Liu, Dan; Li, Fengting; Hui, Franck; Lédion, Jean

2010-11-01

198

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...

199

Remote sensing of algal blooms by aircraft and satellite in Lake Erie and Utah Lake  

NASA Technical Reports Server (NTRS)

During late summer, when the surface waters of Lake Erie reach their maximum temperature, an algal bloom is likely to develop. Such phenomena, which characterize eutrophic conditions, have been noticed on other shallow lakes using the Earth Resources Technology Satellite (ERTS-1). The concentration of the algae into long streamers provides additional information on surface circulations. To augment the ERTS Multispectral Scanner Subsystem data of Lake Erie, an aircraft was used to obtain correlative thermal-IR and additional multiband photographs. A large bloom of Aphanizomenon flos-aquae observed in Utah Lake together with recent bloom history in Lake Erie is used to verify the Great Lakes bloom.

Strong, A. E.

1974-01-01

200

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

201

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

202

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...

203

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.

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

2013-01-01

204

Longitudinal hydrodynamic characteristics in reservoir tributary embayments and effects on algal blooms.  

PubMed

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

205

The Role of Allelopathy for Harmful Algae Bloom Formation  

Microsoft Academic Search

Strong evidence has accumulated on the last years that some algal species are able to kill not only their grazers but also\\u000a other algal species, a process called allelopathy. Killing the nutrient-competing phytoplankton species enable these species\\u000a to freely utilize limiting resources such as nitrogen and phosphorus. While for some algal species, like e.g. the flagellate\\u000a Prymnesium sp., the allelochemicals

Edna Granéli; Paulo S. Salomon; Giovana O. Fistarol

206

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

207

[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

208

Freshly prepared rat hepatocytes used in screening the toxicity of blue?green algal blooms  

Microsoft Academic Search

The acute toxicity of extracts of blue?green algae was tested in freshly prepared rat hepatocytes in suspension. The results were compared with the traditional in vivo mouse bioassay. Sixty samples of natural algal blooms from freshwater lakes in Norway, Sweden, and Finland and 14 samples cultured in the laboratory were tested. The mouse bioassay revealed hepatotoxins in a large number

Kjetil Berg; Tore Aune

1987-01-01

209

Modelling the effects of macrophytes on algal blooming in eutrophic shallow lakes  

Microsoft Academic Search

A dynamic model for eutrophication incorporating phytoplankton and nutrients in the overlying water, submerged macrophytes Potamogeton pectinatus L., and nutrient dynamics in sediments was developed as a functional tool to understand the effects of macrophytes on algal blooming in shallow lakes. The submodule for the overlying water treats three types of phytoplankton (diatoms, green and blue green algae), the macro-nutrients,

Takashi Asaeda; Truong Van Bon

1997-01-01

210

Effect of coagulation on nutrient and light limitation of an algal bloom  

Microsoft Academic Search

Coagulation is the formation of large particles 'from multiple collisions of smaller ones. Because larger particles fall faster than smaller ones, coagulation can be important in accelerating the export of organic matter from the ocean's surface to the deep sea and has the potential to limit phyto- plankton populations. We have developed a model of an algal bloom that includes

GEORGE A. JACKSON; STEVE E. LOCHMANN

1992-01-01

211

CuSO 4 treatment of nuisance algal blooms in drinking water reservoirs  

Microsoft Academic Search

Since the turn of the century, copper sulfate has been used extensively as an algicide to control nuisance algal blooms in drinking water reservoirs Recent experimental results have shown that the toxicity of copper to algae is determined by the activity of ionic copper, and not the total copper concentration The sensitivity of algae to ionic copper has been found

Diane M. McKnight; Sallie W. Chisholm; Donald R. F. Harleman

1983-01-01

212

In-lake algal bloom removal and submerged vegetation restoration using modified local soils  

Microsoft Academic Search

A “modified local soil induced ecological restoration” (MLS-IER) technology was developed for the restoration of degraded shallow lakes. Modified local soils that mixed with macrophyte seeds were used to flocculate the algal blooms and sink them down to the bottom of the lake. The increased water clarity and the improved sediment quality due to the covering of clean modified local

Gang Pan; Bo Yang; Dan Wang; Hao Chen; Bing-hui Tian; Mu-lan Zhang; Xian-zheng Yuan; Juan Chen

2011-01-01

213

ERTS-1 observes algal blooms in Lake Erie and Utah Lake  

NASA Technical Reports Server (NTRS)

During late summer when the surface waters of Lake Erie reach their maximum temperature an algal bloom is likely to develop. Such phenomena have been noticed on other shallow lakes using ERTS-1 and characterize eutrophic conditions. The concentration of the algae into long streamers provides additional information on surface circulations. To augment the ERTS-1 MSS data of Lake Erie an aircraft was flown to provide correlative thermal-IR and additional multiband photographs. The algal bloom is highly absorptive in the visible wavelengths but reverses contrast with the surrounding water in the near-IR bands. The absorption of shortwave energy heats the dark brown algal mass, providing a hot surface target for the thermal-IR scanner.

Strong, A. E.

1973-01-01

214

Fuzzy prediction of the algal blooms in the Orbetello lagoon  

Microsoft Academic Search

The Orbetello lagoon is a shallow brackish waterbody subject to intense and diverse eutrophication (phytoplankton, macroalgae and macrophytes). Periodically a large amount of algae must be artificially removed, their collection and disposal representing a considerable management cost. This paper describes the design of a bloom predictor based on the daily fluctuations of simple water quality parameters such as dissolved oxygen,

Stefano Marsili-libelli

2004-01-01

215

Monitoring Algal Blooms in a Southwestern U.S. Reservoir System  

NASA Astrophysics Data System (ADS)

In recent years, several studies have explored the potential of higher-resolution sensor data for monitoring phytoplankton primary production in coastal areas and lakes. Landsat data have been used to monitor algal blooms [Chang et al., 2004; Vincent et al., 2004], and Moderate Resolution Imaging Spectroradiometer (MODIS) 250-meter and Medium Resolution Imaging Spectrometer (MERIS) full-resolution (300-meter) bands have been utilized to detect cyanobacterial blooms [Reinart and Kutser, 2006] as well as to monitor water quality [Koponen et al., 2004]. Field sampling efforts and MODIS 250-meter data are now being combined to develop a cost-effective method for monitoring water quality in a southwestern U.S. reservoir system. In the Phoenix, Ariz., metropolitan area, the Salt River reservoirs supply more than 3.5 million people, a population expected to rise to more than 6 million by 2030. Given that reservoir capacities have physical limitations, maintaining water quality will become critical as the population expands. Potentially noxious algal blooms that can release toxins and may affect water quality by modifying taste and odor have become a major concern in recent years. While frequent field sampling regimes are expensive, satellite imagery can be applied cost-effectively to monitor algal biomass trends remotely, and this information could provide early warning of blooms in these reservoirs.

Tarrant, Philip; Neuer, Susanne

2009-02-01

216

Norwegian remote sensing spectrometry for mapping and monitoring of algal blooms and pollution - NORSMAP-89  

SciTech Connect

During the late spring of 1988 an extensive bloom of the toxic algae Chrysocromulina polylepis occurred in the Skagerrak region influencing most life in the upper 30 meter of the ocean. The algal front was advected northward with the Norwegian Coastal Current along the coast of southern Norway, where it became a severe threat to the Norwegian seafarming industry. An ad-hoc expert team was established to monitor and forecast the movement of the algae front. Remote sensing of sea surface temperature from the operational US NOAA satellites monitored the movement of the algal front, consistent with a warm ocean front. The lack of any optical remote sensing instrumentation was recognized as a major de-efficiency during this algal bloom. To prepare for similar events in the future Nansen Remote Sensing Center initiated a three week pilot study in the Oslofjord and Skagerrak region, during May 1989. The Canadian Compact Airborne Spectrographic Imager (CASI) was installed in the surveillance aircraft. Extensive in situ campaigns was also carried out by the Norwegian Institute for Water Research and Institute of Marine Research. A ship-borne non-imaging spectrometer was operated from the vessels participating in the field campaign. As a contribution from a joint campaign (EISAC '89) between the Joint Research Centre (JRC) of the European Community and the European Space Agency (ESA) both the Canadian Fluorescence Line Imager (FLI) and the US 64-channel GER scanner was operated simultaneously at the NORSMAP 89 test site. Regions of different biological and physical conditions were covered during the pilot study and preliminary analysis are obtained from oil slicks, suspended matter from river, as well as minor algal bloom. The joint analysis of the data collected during the NORSMAP 89 campaign and conclussions will be presented, as well as suggestions for future utilization of airborne spectroscopy systems for operational monitoring of algal bloom and water pollution.

Pettersson, L.H.; Johannessen, O.M.; Frette, O. (Nansen Remote Sensing Center, Bergen (Norway))

1990-01-09

217

Seasonal and annual dynamics of harmful algae and algal toxins revealed through weekly monitoring at two coastal ocean sites off southern California, USA.  

PubMed

Reports of toxic harmful algal blooms (HABs) attributed to the diatom Pseudo-nitzschia spp. have been increasing in California during the last several decades. Whether this increase can be attributed to enhanced awareness and monitoring or to a dramatic upswing in the development of HAB events remains unresolved. Given these uncertainties, the ability to accurately and rapidly identify an emerging HAB event is of high importance. Monitoring of HAB species and other pertinent chemical/physical parameters at two piers in southern California, Newport and Redondo Beach, was used to investigate the development of a site-specific bloom definition for identifying emerging domoic acid (DA) events. Emphasis was given to abundances of the Pseudo-nitzschia seriata size category of Pseudo-nitzschia due to the prevalence of this size class in the region. P. seriata bloom thresholds were established for each location based on deviations from their respective long-term mean abundances, allowing the identification of major and minor blooms. Sixty-five percent of blooms identified at Newport Beach coincided with measurable DA concentrations, while 36 % of blooms at Redondo Beach coincided with measurable DA. Bloom definitions allowed for increased specificity in multiple regression analysis of environmental forcing factors significant to the presence of DA and P. seriata. The strongest relationship identified was between P. seriata abundances 2 weeks following upwelling events at Newport Beach. PMID:23288675

Seubert, Erica L; Gellene, Alyssa G; Howard, Meredith D A; Connell, Paige; Ragan, Matthew; Jones, Burton H; Runyan, Jennifer; Caron, David A

2013-10-01

218

Use of artificial neural network in the prediction of algal blooms.  

PubMed

A model to quantify the interactions between abiotic factors and algal genera in Lake Kasumigaura, Japan was developed using artificial neural network technology. Results showed that the timing and magnitude of algal blooms of Microcystis, Phormidium and Synedra in Lake Kasumigaura could be successfully predicted. As for the newly occurring dominant Oscillatoria, results were not satisfactory. The evaluation of the importance of factors showed that Microcystis, Phormidium, Oscillatoria and Synedra were alkalophilic. The algal proliferation for Microcystis, Oscillatoria and Synedra decrease due to the increase in total nitrogen, while the growth of Phormidium is enhanced with more nitrogen. In addition, the algal density is affected by zooplankton grazing but with the exception of Phormidium due to it being poor food source. Algal responses to the orthogonal combinations of the external environmental factors, chemical oxygen demand, pH, total nitrogen and total phosphorus at three levels were modeled. Various combinations of environmental factors enhance the proliferation of some algae while other combinations inhibit bloom formation. PMID:11337850

Wei, B; Sugiura, N; Maekawa, T

2001-06-01

219

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

220

The influence of upwelling and entrainment on the algal bloom in the Baltic Sea  

NASA Astrophysics Data System (ADS)

Hydrodynamic processes control many geochemical and ecological processes in the sea. In this paper, the influence of up- and downwelling and entrainment on the ecosystem components are studied. The ecohydrodynamic model was initially used to simulate the whole Baltic Sea to get the boundary conditions for the Gulf of Riga. Then, to study the influence of different hydrodynamic conditions on the algal bloom, three simulations were made for the Gulf of Riga using different boundary and entrainment conditions. It appears that upwelling in the gulf was strongly dependent on open boundary conditions between the Baltic Proper and the gulf. The vertical transport in the Gulf of Riga was many times more intensive in the calculation system Baltic Proper and Gulf of Riga, than in the case where only the Gulf of Riga was simulated. The blue-green algal bloom was influenced by the vertical transport due to different nutrients' limitation mechanism.

Ennet, Peeter; Kuosa, Harri; Tamsalu, Rein

2000-07-01

221

Artificial neural network approach for modelling and prediction of algal blooms  

Microsoft Academic Search

Following a comparison of current alternative approaches for modelling and prediction of algal blooms, artificial neural networks are introduced and applied as a new, promising model type. The neural network applications were developed and validated by limnological time-series from four different freshwater systems. The water-specific time-series comprised cell numbers or biomass of the ten dominating algae species as observed over

Friedrich Recknagel; Mark French; Pia Harkonen; Ken-Ichi Yabunaka

1997-01-01

222

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).

Gonzalez, Jose M.; Simo, Rafel; Massana, Ramon; Covert, Joseph S.; Casamayor, Emilio O.; Pedros-Alio, Carlos; Moran, Mary Ann

2000-01-01

223

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.

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

224

Individual and combined suppressive effects of submerged and floating-leaved macrophytes on algal blooms.  

PubMed

Shallow lakes and ponds are often characterised either by clear water with abundant submerged macrophytes or by turbid water with abundant phytoplankton. Blooms of toxic filamentous blue-green algae (cyanobacteria) often dominate the phytoplankton community in eutrophic lakes, which threatens ecological functions and biodiversity of freshwater ecosystems. We studied a simple lake model in order to evaluate individual and combined suppressive effects of rooted submerged and rooted floating-leaved macrophytes on algal blooms. Floating-leaved plants are superior competitors for light, whereas submerged plants absorb and reduce available phosphorus in a water column that rooted floating-leaved plants exploit to a lesser extent. We found that mixed vegetation that includes both submerged and floating-leaved plants is more resistant than vegetation comprised by a single plant type to algal invasion triggered by phosphorus loading. In addition, competitive exclusion of submerged plants by floating-leaved plants may promote an algal bloom. These predictions were confirmed by the decision tree analysis of field data from 35 irrigation ponds in Hyogo Prefecture, Japan. PMID:23219493

Seto, Mayumi; Takamura, Noriko; Iwasa, Yoh

2013-02-21

225

The effect of hydrodynamic flow regimes on the algal bloom in a monomictic reservoir.  

PubMed

The effectiveness of a proposed curtain weir to be installed in the transitional zone of a eutrophic reservoir located in monsoon areas on the control of algal blooms in the lacustrine zone where drinking water withdrawals occur was assessed with various hydrodynamic flow regimes. A two-dimensional hydrodynamic and eutrophication model that can accommodate vertical displacement of the weir following the water surface changes was developed and validated using field data obtained from two distinctive hydrological years; drought (2001) and wet (2004). The model adequately reproduced the temporal and spatial variations of temperature, nutrients and phytoplankton concentrations in the reservoir. The efficacy of the curtain weir method found to be diverse for different hydrological conditions and dependent on the inflow densimetric Froude number (Fr(i)). Algal blooming was considerably mitigated by curtailing the transport of nutrients and algae from riverine zone to lacustrine epilimnion zone during the drought year as long as Fr(i) < 1.0. However, some flood events with Fr(i) > 1.0 transported nutrients and algae built upstream of the weir into the downstream euphotic zone by strong entrainments in 2004. Numerical experiments revealed that the efficiency of the weir on the control of algal blooming becomes marginal if the Fr(i) > 3.0. PMID:18845869

Chung, Se-Woong; Lee, Heungsoo; Jung, Yongrock

2008-01-01

226

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

Microsoft Academic Search

Cyanobacterial blooms in Lake Taihu occurred at the end of April 2007 and had crucial impacts on the livelihood of millions\\u000a of people living there. Excessive nutrients may promote bloom formation. Atmospheric nitrogen (N) and phosphorus (P) deposition\\u000a appears to play an important role in algal bloom formation. Bulk deposition and rain water samples were collected respectively\\u000a from May 1

Shuijing Zhai; Longyuan Yang; Weiping Hu

2009-01-01

227

Landsat TM image feature extraction and analysis of algal bloom in Taihu Lake  

NASA Astrophysics Data System (ADS)

This study developed an approach to the extraction and characterization of blue-green algal blooms of the study area Taihu Lake of China with the Landsat 5 TM imagery. Spectral feature of typical material within Taihu Lake were first compared, and the most sensitive spectral bands to blue-green algal blooms determined. Eight spectral indices were then designed using multiple TM spectral bands in order to maximize spectral contrast of different materials. The spectral curves describing the variation of reflectance at individual bands with the spectral indices were plotted, and the TM imagery was segmented using as thresholds the step-jumping points of the reflectance curves. The results indicate that the proposed multiple band-based spectral index NDAI2 (NDAI2 = (B4-B1)*(B5-B3)/(B4+B5+B1+B3) performed better than traditional vegetation indices NDVI and RVI in the extraction of blue-green algal information. In addition, this study indicates that the image segmentation using the points where reflectance has a sudden change resulted in a robust result, as well as a good applicability.

Wei, Yuchun; Chen, Wei

2008-05-01

228

Harmful microalgae blooms (HAB); problematic and conditions that induce them.  

PubMed

HAB occurrence is becoming more frequent and problematic in marine recreational waters. However, the exploitation of the coastal area for recreational use is promoting the necessary conditions for the HAB increase. In terms of the harmful effects, we can consider two types of causative organism: the toxic producers and the high-biomass producers. Toxic events can be produced by a very low concentration of the causative organism. This characteristic implies a difficulty for the monitoring programs in relation to human health. It is important to point out in the context of human health and HAB events, that in some coastal regions (e.g. the Mediterranean basin) HABs are an emerging problem. In these regions, the local population and visitors may face a health risk that is difficult to measure. The monitoring of toxic species has mainly been associated -with shellfish farming. However, the risk of intoxication could become even greater in areas not subject to legislation of aquaculture activities. PMID:17010385

Masó, Mercedes; Garcés, Esther

2006-01-01

229

Remote Sensing as a Tool to Track Algal Blooms in the Great Salt Lake, Utah, USA  

NASA Astrophysics Data System (ADS)

The Great Salt Lake is a large hypersaline, terminal water body in northern Utah, USA. The lake has both a significant economic importance to the local community as a source of brine shrimp and mineral resources, as well as, an ecological importance to large numbers of migratory waterfowl. Due to nutrient input from sewage treatment plants, sections of the Great Salt Lake are subjected to highly eutrophic conditions. One of the main tributaries, Farmington Bay, experiences massive blooms of cyanobacteria which can reach concentrations in excess of 300 mg l-1 in the bay. Effects of these blooms can be observed stretching into the rest of the lake. The detrimental outcomes of the blooms include unsightly scums, foul odor and the danger of cyanobacterial toxins. While the blooms have an obvious effect on Farmington Bay, it is quite possible that the cyanobacteria impact a much wider area of the lake as currents move eutrophic water masses. Of particular interest is the reaction of brine shrimp to the plumes of cyanobacteria-rich water leaving Farmington Bay. We are employing remote sensing as a tool to map the distribution of algae throughout the lake and produce lake-wide maps of water quality on a regular basis. On-lake reflectance measurements have been coupled with MODIS satellite imagery to produce a time series of maps illustrating changes in algal distribution. The successes and shortcomings of our remote sensing technique will be a central topic of this presentation.

Bradt, S. R.; Wurtsbaugh, W. A.; Naftz, D.; Moore, T.; Haney, J.

2006-12-01

230

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

231

Modelling multi-species algal bloom in a lake and inter-algal competitions.  

PubMed

A numerical model was developed to simulate water quality and algal species composition in a deep lake. As artificial destratification is widely used in the lakes, a destratification (bubble plume) model was incorporated with the ecological model to simulate the dynamic responses of different species under artificial mixing. The ecological model predicts concentrations of PO(4)-P, NH(4)-N, NO(3)-N, DO and pH throughout the water column, all of which have a significant influence on the growth of different algal species. The model has been calibrated using data from Uokiri Lake (Japan) for two different species (Diatom and Cyanobacteria) with and without artificial mixing. The calibrated model was used to simulate different conditions of artificial mixing within the lake over a period of five months. The simulation results show that artificial mixing favors non-motile heavier species, such as Diatom, while preventing the growth of Blue-green algae. It is also demonstrated that intermittent operation of the artificial mixing is better for water quality amelioration than continuous operation. PMID:19923766

Imteaz, Monzur Alam; Shanableh, Abdallah; Asaeda, Takashi

2009-01-01

232

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

233

Comparative application of artificial neural networks and genetic algorithms for multivariate time-series modelling of algal blooms in freshwater lakes  

Microsoft Academic Search

The paper compares potentials and achievements of artificial neural networks and genetic algorithms in terms of forecasting and understanding of algal blooms in Lake Kasumigaura (Japan). Despite the complex and nonlinear nature of ecological data, artificial neural networks allow seven-days-ahead predictions of timing and magnitudes of algal blooms with reasonable accuracy. Genetic algorithms possess the capability to evolve, refine and

Friedrich Recknagel; Jason Bobbin; Peter Whigham; Hugh Wilson

2002-01-01

234

Does Low Temperature Constrain the Growth Rates of Heterotrophic Protists? Evidence and Implications for Algal Blooms in Cold Waters  

Microsoft Academic Search

Literature review and synthesis of growth rates of aquatic protists focused on the role of temperature in the formation of massive annual algal blooms in high-latitude ecosystems. Maximal growth rates of herbivorous protists equaled or exceeded maximal growth rates of phototrophic protists at temperatures above 15°C. Maximal growth rates of herbivorous protists declined more rapidly with decreasing temperature than did

Julie M. Rose; David A. Caron

2007-01-01

235

Harmful algal toxins of the Florida red tide (Karenia brevis): natural chemical stressors in South Florida coastal ecosystems  

PubMed Central

The Florida red tide is a descriptive name for high concentrations of the harmful marine alga, Karenia brevis. Although most prevalent along the south-west Florida coast, periodic blooms have occurred throughout the entire US and Mexico Gulf coasts and the Atlantic coast to North Carolina. This dinoflagellate produces a suite of polyether neurotoxins, called brevetoxins, that cause severe impacts to natural resources, as well as public health. These naturally produced biotoxins may represent one of the most common chemical stressors impacting South Florida coastal and marine ecosystems. Impacts include massive fish kills, marine mammal, sea turtle and sea bird mortalities, benthic community die-off and public health effects from shellfish contamination and inhalation of air-borne toxins. The primary mode of action is binding to voltage-gated sodium channels causing depolarization of nerve cells, thus interfering with nerve transmission. Other effects include immune depression, bronchial constriction and haemolysis. Parent algal toxins are synthesized within the unicellular organism, others are produced as metabolic products. Recent studies into the composition of brevetoxins in cells, water, air and organisms have shown PbTx-2 to be the primary intracellular brevetoxin that is converted over time to PbTx-3 when the cells are ruptured, releasing extracellular brevetoxins into the environment. Brevetoxins become aerosolized by bubble-mediated transport of extracellular toxins, the composition of which varies depending on the composition in the source water. Bivalved molluscs rapidly accumulate brevetoxins as they filter feed on K. brevis cells. However, the parent algal toxins are rapidly metabolized to other compounds, some of which are responsible for neurotoxic shellfish poisoning (NSP). These results provide new insight into the distribution, persistence and impacts of red tide toxins to south-west Florida ecosystems.

Henry, M. S.

2009-01-01

236

Analysis of pollutant enhanced bacterial-blue-green algal interrelationships potentiating surface water contamination by noxious blue-green algal blooms. Completion report  

SciTech Connect

Sulfate-reducing bacteria from the genus Desulfovibro can stimulate the blue-green alga (Cyanobacterium) Anabaena variabilis (Strain 6411) into increasing its dry weight biomass production by more than 200 percent over that of the control as the total phosphate in the medium approaches zero. Results suggest that methods which utilize total nitrogen to phosphorus ratios in waters as predictors of blue-green algal 'blooms' may be unreliable when the waters are very low in phosphorus yet remain high in sulfate with conditions favorable for sulfate-reducing bacterial growth in benthic sediments. Otherwise, if the phosphate levels alone in the aqueous systems are reduced below threshold levels under these conditions, the magnitude of the blue-green algal blooms may be increased substantially.

Bedell, G.W.

1984-02-01

237

Regional variability of factors controlling the onset timing and magnitude of spring algal blooms in the northwestern North Pacific  

NASA Astrophysics Data System (ADS)

Satellite imagery and oceanographic data collected between 2003 and 2009 were used to examine factors controlling the onset timing and magnitude of spring algal blooms in the northwestern North Pacific. Consistent with the critical depth hypothesis, the spring bloom onsets coincided with the mixed layer depth (MLD) shoaling in the north of the Kuroshio extension and in Oyashio, where complex frontal physical structures and turbulence weakening, respectively, would be responsible for the MLD shoaling. In contrast, in the formation regions of the dense central mode water (D-CMW) and the transition region mode water (TRMW), bloom onsets coincided with possible turbulence weakening but not with MLD shoaling. The peak of chlorophyll a in the formation regions of the D-CMW (0.44 ± 0.23 mg m-3) and the TRMW (0.58 ± 0.34 mg m-3) were ca. 5 times lower than that in the Oyashio (2.54 ± 0.74 mg m-3), despite the fact that nitrate concentration during the prebloom period was high (˜10 µM) and MLDs became shallow enough at the bloom peak in all the three regions. These observations indicated that light conditions and nitrate concentration did not explain the regional variability in the magnitude of spring blooms. The bloom magnitude west of ca. 150°E and in the north Kuroshio extension was increased relative to that in the eastern region, suggesting a chemical property in the water delivered from the Okhotsk Sea that would influence the western bloom. Our results demonstrated that factors controlling the timing and magnitude of spring algal blooms depend on the physicochemical regime in the northwestern North Pacific.

Shiozaki, Takuhei; Ito, Shin-Ichi; Takahashi, Kazutaka; Saito, Hiroaki; Nagata, Toshi; Furuya, Ken

2014-01-01

238

Remote sensing of harmful algal events in optically complex waters using regionally specific neural network-based algorithms for MERIS data  

NASA Astrophysics Data System (ADS)

In typical case 2 waters an accurate remote sensing retrieval of chlorophyll a (chla) is still challenging. There is a widespread understanding that universally applicable water constituent retrieval algorithms are currently not feasible, shifting the research focus to regionally specific implementations of powerful inversion methods. This study takes advantage of regionally specific chlorophyll a (chla) algorithms, which were developed by the authors of this abstract in previous works, and the characteristics of Medium Resolution Imaging Spectrometer (MERIS) in order to study harmful algal events in the optically complex waters of the Galician Rias (NW). Harmful algal events are a frequent phenomenon in this area with direct and indirect impacts to the mussel production that constitute a very important economic activity for the local community. More than 240 106 kg of mussel per year are produced in these highly primary productive upwelling systems. A MERIS archive from nine years (2003-2012) was analysed using regionally specific chla algorithms. The latter were developed based on Multilayer perceptron (MLP) artificial neural networks and fuzzy c-mean clustering techniques (FCM). FCM specifies zones (based on water leaving reflectances) where the retrieval algorithms normally provide more reliable results. Monthly chla anomalies and other statistics were calculated for the nine years MERIS archive. These results were then related to upwelling indices and other associated measurements to determine the driver forces for specific phytoplankton blooms. The distribution and changes of chla are also discussed.

Gonzalez Vilas, L.; Castro Fernandez, M.; Spyrakos, E.; Torres Palenzuela, J.

2013-08-01

239

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

240

The Harmful Algae Page  

NSDL National Science Digital Library

Produced by the National Office of Marine Biotoxins and Harmful Algal Blooms and housed at the Woods Hole Oceanographic Institution, this site covers the dark side of the organisms that provide the foundation for almost all marine life. The site focuses on the small number of algae that produce potent neurotoxins that "can be transferred through the food web where they affect and even kill the higher forms of life such as zooplankton, shellfish, fish, birds, marine mammals, and even humans that feed either directly or indirectly on them." The site is divided into the following sections: photos of "Red Tide" blooms, species responsible for harmful effects, adverse impacts at higher trophic levels, human illness associated with algal blooms, and effects in your region. Researchers, educators, and people with interests in such recent headline topics such as the Pfiesteria scare can all find useful information at this site.

., Woods H.

1997-01-01

241

Inhibitory analysis of top-down control: new keys to studying eutrophication, algal blooms, and water self-purification  

Microsoft Academic Search

Ostroumov S.A. Inhibitory analysis of top-down control: new keys to studying eutrophication, algal blooms, and water self-purification. – Hydrobiologia. 2002, vol. 469, p. 117-129; http:\\/\\/www.scribd.com\\/doc\\/52598579\\/; http:\\/\\/b23.ru\\/nwmb; It is the first article in which the new experimental data of the author were analyzed to give new fresh insight into ecological mechanisms of eutrophication and abnormal increase in phytoplankton. Also, new insight

S. A. Ostroumov

2002-01-01

242

Diel fluctuations in bacterial activity on streambed substrata during vernal algal blooms: Effects of temperature, water chemistry, and habitat  

Microsoft Academic Search

Diel fluctuations in stream water temperature and chemistry, microbial biomass, and bacterial activity were measured in White Clay Creek, Pennsylvania, during vernal algal blooms in three different years. DOC concentrations increased 24-37% over early morning minima and temperature increased nearly 10°C over a 7-10-h period. Total carbohydrates and monosaccharides exhibited irregular fluctuations with total carbohydrates showing concentration peaks in the

LOUIS A. KAPLAN; THOMAS L. BOTT

1989-01-01

243

[Harmful blooms of cyanobacteria (Oscillatoriaceae) and dinoflagellates (Gymnodiniaceae) in the Golfo de Nicoya, Costa Rica].  

PubMed

Recently, the Pacific coast of Costa Rica has experienced an increase in both magnitude and frequency of harmful algae blooms (HAB). The lack of data regarding the dynamics of these events in the area, and the species of microalgae that produce them, are themes of great interest. The blooms have produced negative impacts on fishery resources and on human health in Costa Rica. In May 2002 a HAB left a large number of dead fish along the central Pacific coast. Water samples were collected using a phytoplankton net and fixed for subsequent processing by electron microscopy. In addition, a one liter sample of surface water was taken for later cell count. In the observed HAB, the dominating organisms found were the cyanobacteria Trichodesmiun erythraeum surrounded by high concentrations of Gram-bacteria and the dinoflagellate Cochlodinium cf. polykrikoides. T. erythraeum, is one of the most important N2 fixing cyanobacteria in marine waters that has been associated with HAB events in diverse parts of the world as well as with symptoms that produce contact dermatitis and other discomforts. C. cf. polykrikoides is a dinoflagellete associated with fish kills; although the type of associated toxins are unknown. In a national newspaper 17 cases of intoxication in humans were reported during this same period, which presented respiratory disorders and burning of the eyes. This is the first report in Costa Rica where a cyanobacteria and a dinoflagellate were observed together producing HAB. PMID:17465125

Vargas-Montero, Maribelle; Freer, Enrique

2004-09-01

244

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

245

Approaches to model the life cycle of harmful algae  

Microsoft Academic Search

Models of harmful algal blooms (HABs) need to include autecological characteristics of the HAB species because the bloom dynamics can only be successfully described if relevant life cycle aspects (in particular en- and excystment) are included in some way. This study presents an overview on how the life cycle is considered in current Lagrangian and Eulerian models. Examples of the

Inga Hense

2010-01-01

246

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

247

[Structural characteristics of phytoplankton community during harmful algae bloom in Jiaozhou Bay].  

PubMed

Based on two days survey in August, 2001 in Jiaozhou Bay, the structural characteristics of phytoplankton community during harmful algae bloom was studied. The results showed that phytoplankton community was composed mainly by the coastal warm species, which were dominated by the diatom including 37 species. Only 7 Pyrrorophya and 1 Chlorophyta species were identified. The highest value of species number appeared in the central of Jiaozhou Bay, which included 37 species, but the lowest value in the edge of Jiaozhou Bay was only 10 species. The highest value of cell abundance appeared in the eastern waters of Jiaozhou Bay, being 6.96 x 10(3) cell.m-3, and the lowest value appeared in the mouth of Jiaozhou Bay, being 3.18 x 10(6) cell.m-3. The diversity and eveness of phytoplankton was the lowest in the eastern waters of Jiaozhou bay, but was higher in the mouth and the central of Jiaozhou Bay. Water mass movement and eutrophication were the main factors affecting the distribution of phytoplankton community in Jiaozhou Bay. PMID:14997657

Liu, Dongyan; Sun, Jun; Zhang, Liyong

2003-11-01

248

Forecast of Algal Bloom Dynamics in a River Using the Ensemble Kalman Filter  

NASA Astrophysics Data System (ADS)

A forecasting framework of algal bloom in a river channel was developed by employing two numerical models coupled in serial order to simulate a watershed and the main river channel. The HSPF model simulates flow discharge and water quality from the watershed and the EFDC model takes the results as inputs to simulate river channel hydrodynamics and water quality. The ensemble Kalman filter (EnKF) was applied for data assimilation in the framework, linking uncertainties of inputs, model structures and observations. The input precipitation and water quality from point sources were perturbed to form ensemble members of state variables. The perturbation generated the ensemble of flow discharges and concentrations of water quality variables including Chl-a from HSPF model simulations, which were fed into the EFDC model. Stochastic forcing terms to simulate model structural errors were added for both models. Also an error distribution was used to address the measurement error. The framework was applied to theYoungsan River watershed, which is located in southwestern area of the Korean Peninsula (about 3,470 km2). The weather forecast data provided by Korean Meteorological Agency, consisting of combined data from the UM-Regional and UM-Global models, were used through the forecasting simulations. The HSPF model was calibrated for the observed flow and water quality data of 2009 to 2010 and the EFDC model for the data of 2008 to 2009 before they are used in forecasting. Data assimilation was conducted with weekly Chl-a data sampled along the river channel by updating Chl-a concentrations on the EFDC model grids. To keep mass conservation of water quality constituents, the other variables are also updated correspondingly, considering the changes due to growth, death and respiration of algae. The results show that EnKF works efficiently for updating spatial distribution of Chl-a concentrations. However, since the ensemble inputs at the boundary locations produced by the HSPF model are not updated, the effect of the update along the main channel is washed out after a couple of days by the inputs from tributaries, which is the limitation of the current study. This defect is expected to be decreased when flow residence time increases by two weirs recently constructed or when more frequent updating is possible by using real-time data from the automated water quality stations newly installed on the river.

Kim, K.; Ryu, I.; Min, J.; Shin, K.; Park, L.

2011-12-01

249

Modeling Algal Bloom Dynamics in a River Using the Ensemble Kalman Filter  

NASA Astrophysics Data System (ADS)

A forecasting framework of algal bloom in a river channel was developed by employing two numerical models coupled in a serial order to simulate a watershed and the main river channel and the ensemble Kalman filter (EnKF) for data assimilation (DA). The HSPF model simulates flow discharge and water quality from the watershed and the EFDC model takes the results as boundary forcing to simulate river hydrodynamics and water quality. The ensemble Kalman filter (EnKF) was applied for DA in the framework, linking uncertainties of model simulations and observations. Stochastic error models to describe HSPF model simulation uncertainty were formed by comparing the simulation and observation values. The ensemble of the simulated HSPF model outputs, generated from the error models, reflect the uncertainties in the HSPF model's initial conditions, model structure and boundary conditions such as meteorological data and water quality data for point pollutant sources. Stochastic forcing terms to consider the model error of the EFDC model and observational error were added during the ensemble simulation of the EFDC model. The framework was applied to a section of the Han River watershed, located in the mid-eastern area of the Korean Peninsula. The HSPF and EFDC models were calibrated before they are used for hindcastings of the first nine months of 2012. DA was conducted with weekly chlorophyll-a (chl-a) data sampled along the river channel by updating chl-a concentrations of the EFDC model grids. The results show that EnKF works efficiently for updating spatial distribution of chl-a concentrations in the downstream part of the river section where flow retention time is relatively long. However, for the upstream part of river section with relatively fast flow, since the ensemble forcing at the tributary confluence points produced by the error models are not updated, the effect of DA is flushed away in just a couple of days by the flow from tributaries. In order to quantify uncertainties attributed to the errors in the flow and other water quality variables simulated by the HSPF model, additional simulations were carried out by allowing ensemble run only for flow and phosphate respectively. The chl-a ensemble spread of the case of -flow-ensemble-run-only was narrow then the case of ensemble-run-for-all, showing that the portion of uncertainty attributed to the flow simulation can be separated in this way. Similar results were obtained for the case of phosphate-ensemble-run-only.

Kim, K.; Park, M.; Min, J.; Ryu, I.; Kang, M.; Park, L.

2013-12-01

250

REAL-TIME MONITORING FOR TOXICITY CAUSED BY HARMFUL ALGAL BLOOMS AND OTHER WATER QUALITY PERTURBATIONS  

EPA Science Inventory

This project, sponsored by EPA's Environmental Monitoring for Public Access and Community Tracking (EMPACT) program, evaluated the ability of an automated biological monitoring system that measures fish ventilatory responses (ventilatory rate, ventilatory depth, and cough rate) t...

251

Real-Time Monitoring for Toxicity Caused by Harmful Algal Blooms and Other Water Qualtiy Perturbations.  

National Technical Information Service (NTIS)

This project, sponsored by EPA's Environmental Monitoring for Public Access and Community Tracking (EMPACT) program, evaluated the ability ofan automated biological monitoring system that measures fish ventilatoryresponses (ventiliatory rate, ventilatory ...

2001-01-01

252

Real-Time Monitoring for Toxicity Caused by Harmful Algal Blooms and Other Water Quality Perturbations.  

National Technical Information Service (NTIS)

This project evaluated an automated biological monitoring system that measures fish ventilatory responses (ventilatory rate, ventilatory depth, and cough rate) to detect developing toxic conditions in water. In laboratory tests, acutely toxic levels of br...

W. Schalie T. Shedd M. Widder A. Kane E. Silbergeld

2001-01-01

253

Coastal eutrophication and harmful algal blooms: Importance of atmospheric deposition and groundwater as \\  

Microsoft Academic Search

Nitrogen-limited csluaries, shallow coastal waters, and continental shelf ivatcrs cover only 15% of the world's ocean area, but account for nearly half the global oceanic primary production. This disproportionality is partly attributed to accelerating and geographically expanding anthropogenic N h-lading and eutrophication. Among ac- celerating N inputs, atmospheric deposition (AD) (as wet- and dryfall) and groundwater (GW) discharge are of

Hans W. Paerl

1997-01-01

254

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...

255

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...

256

Genetic Variation of the Bloom-Forming Cyanobacterium Microcystis aeruginosa within and among Lakes: Implications for Harmful Algal Blooms  

Microsoft Academic Search

an oligotrophic lake (total phosphorus of 10 g liter1 and dissolved inorganic nitrogen:total phosphorus ratio of 12.75) differed among five different medium types (G test, P of <0.001), with higher survival (P 0.003) in low-nutrient media (28 to 37% survival) than in high-nutrient media. Even with the relatively low isolate survivorship that could select against detecting the full range of

Alan E. Wilson; Orlando Sarnelle; Brett A. Neilan; Tim P. Salmon; Michelle M. Gehringer; Mark E. Hay

2005-01-01

257

Experimental Evaluation of Food Chain Manipulation as a Means for Preventing Algal Blooms in Lakes.  

National Technical Information Service (NTIS)

The study investigated means of manipulating lake food chains to enhance grazing by zooplankton and thereby to decrease algal biomass and to improve water clarity. Experiments were conducted at two levels. The authors monitored a relatively deep, stratifi...

W. R. DeMott

1990-01-01

258

Remote sensing studies for the assessment of geohazards: Toxic algal blooms in the lower Great Lakes, and the land subsidence in the Nile Delta  

Microsoft Academic Search

Remote sensing techniques provide valuable tools for assessing a wide variety of environmental phenomena. They have been used for monitoring and assessment of various types of geologic and environmental hazards occurring on land, in the air, or in oceans. I present results from two studies, the first of which examines the spatial and temporal distribution of algal blooms in the

Richard H. Becker

2008-01-01

259

Comparative study of hydrographic conditions for algal bloom formation in the coastal waters of east and west of Hong Kong during 1998  

NASA Astrophysics Data System (ADS)

Phytoplankton abundance was found to be positively correlated with seasonal changes of seawater temperature in Port Shelter and Lamma Channel, Hong Kong in 1998. Rising water temperature from around 20°C to 25°C coincided with an increase in phytoplankton abundance at both locations. Heavy rains from June to September reduced salinity from 30 to 20, but the decrease in salinity was not correlated with a decline in phytoplankton abundance. In spring 1998, over 0.6×106 cells dm-3 and 0.1×106 cells dm-3 of the dinoflagellate, Gymnodinium mikimotoi Miyake et Kominami ex Oda occurred in the coastal waters of Port Shelter and Lamma Channel, respectively. High abundance of the dinoflagellate Ceratium furca (Ehr.) Claparede et Lachmann (>1×106 cells dm-3) produced long-lasting blooms in the waters of Port Shelter from September to October in 1998. The abundances of both diatoms and dinoflagellates were significantly lower in the waters of Lamma Channel than those in Port Shelter due to the less frequent blooms in 1998. Hydrographic conditions such as stable water masses and water column stratification were the main reasons for the differences in the algal abundance and bloom frequency found between the two locations since neither of the two areas appeared to be nutrient-limited. This type water condition for the formation of algal bloom in Port Shelter has not been reported previously and it is not a general case for many bays along China’s coast where algal bloom occurs as well.

Fang, Hongda; Tang, Senming

2009-02-01

260

Application of LDH-release assay to cellular-level evaluation of the toxic potential of harmful algal species.  

PubMed

Lactate dehydrogenase (LDH)-release assay was applied to estimate the toxic potential of harmful algal species at the cellular level. African green monkey kidney (Vero), yellowtail fin epithelia (MJF), and rainbow trout gill (RTgill-W1) cells were used as target cells. A live cell suspension of Karenia mikimotoi (SUO-1) induced the release of LDH from these cell lines, while the activity of another strain, FUK, was much lower. The cell-free culture supernatants and ruptured cell suspensions of both strains of K. mikimotoi were less effective on LDH-release assay. Exposure experiments against abalone and shrimp revealed that SUO-1 showed much stronger lethal effects on these organisms than FUK. Among six phytoplankton species, three species known to be harmful algal species induced the release of LDH to different extents depending on the cell line, whereas the other three species, known to be non-toxic, showed no effects on any cell lines. These results suggest that LDH-release assay is a useful micro-plate assay for estimation of the toxic potential of harmful phytoplankton. PMID:23391929

Zou, Yanan; Kim, Daekyung; Yagi, Motoaki; Yamasaki, Yasuhiro; Kurita, Jun; Iida, Takaji; Matsuyama, Yukihiko; Yamaguchi, Kenichi; Oda, Tatsuya

2013-01-01

261

A simple short range model for the prediction of harmful algal events in the bays of southwestern Ireland  

NASA Astrophysics Data System (ADS)

A simple model is described which predicts harmful algal events in the bays of southwestern Ireland. Fundamental to the model is the physical forcing of circulation in these bays in summer. The predominant hydrographic feature at this time is a wind-driven two-layer oscillatory flow acting in a thermally stratified water column. This mechanism exchanges substantial proportions of the bays' volumes, and harmful algal events arise with the associated transport of harmful populations into them. The model is therefore based on the criterion that wind-driven water exchanges result in exchanges of phytoplankton, which, if the time of year is correct, result in toxic events. Utilising Bantry Bay as an example, hindcasting showed that the model has a high degree of success using a wind index based on the sequence of winds that results in water exchange. The model was implemented by estimating indices from the five-day weather forecast, and trialled in 2005. Results were published on the web in real time, during which a predicted water exchange event in mid-June was accompanied by an influx of Dinophysis acuminata into Bantry Bay with an associated contamination of shellfish with Diarrheic Shellfish Poisoning toxins.

Raine, Robin; McDermott, Georgina; Silke, Joe; Lyons, Kieran; Nolan, Glenn; Cusack, Caroline

2010-11-01

262

Strains of toxic and harmful microalgae, from waste water, marine, brackish and fresh water  

Microsoft Academic Search

Some microalgae are economically important in Mexico and the world because they can be potentially toxic. Algal explosive population growths are named harmful algal blooms and are frequently recorded in Mexico. The authors set up potentially toxic microalgae cultures from the Gulf of Mexico (Garrapatas tideland, Barberena river, Carpintero lagoon in Tamaulipas State; Chalchoapan and Catemaco lakes in Veracruz State),

M. C. Rodríguez-Palacio; L. Crisóstomo-Vázquez; S. Álvarez-Hernández; C. Lozano-Ramírez

2011-01-01

263

Strains of toxic and harmful microalgae, from waste water, marine, brackish and fresh water  

Microsoft Academic Search

Some microalgae are economically important in Mexico and the world because they can be potentially toxic. Algal explosive population growths are named harmful algal blooms and are frequently recorded in Mexico. The authors set up potentially toxic microalgae cultures from the Gulf of Mexico (Garrapatas tideland, Barberena river, Carpintero lagoon in Tamaulipas State; Chalchoapan and Catemaco lakes in Veracruz State),

M. C. Rodríguez-Palacio; L. Crisóstomo-Vázquez; S. Álvarez-Hernández; C. Lozano-Ramírez

2012-01-01

264

Green Scum Up the Bay: Using Linear Modeling to Analyze Algal Blooms in the Chesapeake Bay  

NSDL National Science Digital Library

We used data from the Investigative Case Based Learning case "Back to the Bay" and techniques of analysis from Danny Kaplan's workshop on Multivariate Statistics to analyze the relationship between algal growth (as indicated by chlorophyll levels) and several measures of water quality (dissolved oxygen, water temperature, salinity, pH, & clarity).

Daniel Kaplan (kaplan@macalester.edu;); Amber Johnson (Truman State University;); Justine Bell (Champlain-St. Lambert College;)

2006-06-18

265

A high resolution estimate of the inorganic nitrogen flux from the Scheldt estuary to the coastal North Sea during a nitrogen-limited algal bloom, spring 1995  

NASA Astrophysics Data System (ADS)

Massive short-term (4-8 wk) blooms of Phaeocystis have been observed in coastal North Sea waters in the spring for a number of years now. Researchers have shown that these algal blooms, which lead to eutrophication of the local water mass, are limited by the supply of inorganic nitrogen from the various bordering estuaries. We demonstrate using the case of a typical heavily polluted macrotidal estuary, the Scheldt in Belgium and the Netherlands, that the short duration of the algal blooms requires estuarine flux estimation methods with a high temporal resolution. We use the fully transient, multicomponent reactive transport model CONTRASTE to compute inorganic nitrogen fluxes through the mouth of the Scheldt estuary into the North Sea. The model simulations use a detailed dataset of upstream river discharges and solute concentrations along with tidal forcings for a 210 day period between December 1, 1994 and June 30, 1995. Our temporally resolved estimate shows that widely used estuarine flux estimation methods which rely on a steady-state approximation underestimate the inorganic nitrogen loading available to sustain primary production in the North Sea during the period of the algal bloom by 100%.

Regnier, Pierre; Steefel, Carl I.

1999-05-01

266

A high resolution estimate of the inorganic nitrogen flux from the Scheldt estuary to the coastal North Sea during a nitrogen-limited algal bloom, spring 1995  

SciTech Connect

Massive short-term (4--8 wk) blooms of Phaeocystis have been observed in coastal North Sea waters in the spring for a number of years now. Researchers have shown that these algal blooms, which lead to eutrophication of the local water mass, are limited by the supply of inorganic nitrogen from the various bordering estuaries. The authors demonstrate using the case of a typical heavily polluted macrotidal estuary, the Scheldt in Belgium and the Netherlands, that the short duration of the algal blooms requires estuarine flux estimation methods with a high temporal resolution. They use the fully transient, multicomponent reactive transport model CONTRASTE to compute inorganic nitrogen fluxes through the mouth of the Scheldt estuary into the North Sea. The model simulations use a detailed dataset of upstream river discharges and solute concentrations along with tidal forcings for a 210 day period between December 1, 1994 and June 30, 1995. The temporally resolved estimate shows that widely used estuarine flux estimation methods which rely on a steady-state approximation underestimate the inorganic nitrogen loading available to sustain primary production in the North Sea during the period of the algal bloom by 100%.

Regnier, P. [University College Cork (Ireland). Dept. of Civil and Environmental Engineering] [University College Cork (Ireland). Dept. of Civil and Environmental Engineering; [Free Univ. of Brussels (Belgium). Dept. of Oceanography; Steefel, C.I. [Lawrence Livermore National Lab., CA (United States). Geosciences and Environmental Technologies Div.] [Lawrence Livermore National Lab., CA (United States). Geosciences and Environmental Technologies Div.

1999-05-01

267

Phytoplankton succession in a Eutrophic lake with special reference to blue-green algal blooms  

Microsoft Academic Search

An investigation of phytoplankton in Astotin Lake was made between mid-May of 1966 and September of 1967 with particular attention to the ice-free seasons. Astotin Lake is a typical, small eutrophic, kettle lake with shallow, landlocked, hard water in the Canadian prairies. High concentrations of nutrients supported heavy blooms of blue-green algae throughout the summer. The spring communities were dominated

Chang K. Lin

1972-01-01

268

Trace element transformation during the development of an estuarine algal bloom  

Microsoft Academic Search

Copper and arsenic underwent large changes in chemical form during the development and senescence of natural phytoplankton\\u000a blooms in the Patuxent River, a subestuary of Chesapeake Bay in Maryland. Arsenate was rapidly reduced to arsenite and methylated\\u000a species. At a total arsenic concentration of 20 nmol l?1, arsenate reduction rates ranged from 50 amol cell?1 d?1 to >230 amol cell?1

James G. Sanders; Gerhardt F. Riedel

1993-01-01

269

Algal blooms and the nitrogen-enrichment hypothesis in Florida springs: evidence, alternatives, and adaptive management.  

PubMed

Contradictions between system-specific evidence and broader paradigms to explain ecosystem behavior present a challenge for natural resource management. In Florida (U.S.A.) springs, increasing nitrate (NO3-) concentrations have been implicated as the cause of algal overgrowth via alleviation of N-limitation. As such, policy and management efforts have centered heavily on reduction of nitrogen (N) loads. While the N-limitation hypothesis appears well founded on broadly supported aquatic eutrophication models, several observations from Florida springs are inconsistent with this hypothesis in its present simplified form. First, NO3- concentration is not correlated with algal abundance across the broad population of springs and is weakly negatively correlated with primary productivity. Second, within individual spring runs, algal mats are largely confined to the headwater reaches within 250 m of spring vents, while elevated NO3- concentrations persist for several kilometers or more. Third, historic observations suggest that establishment of macroalgal mats often lags behind observed increases in NO3- by more than a decade. Fourth, although microcosm experiments indicate high thresholds for N-limitation of algae, experiments in situ have demonstrated only minimal response to N enrichment. These muted responses may reflect large nutrient fluxes in springs, which were sufficient to satisfy present demand even at historic concentrations. New analyses of existing data indicate that dissolved oxygen (DO) has declined dramatically in many Florida springs over the past 30 years, and that DO and grazer abundance are better predictors of algal abundance in springs than are nutrient concentrations. Although a precautionary N-reduction strategy for Florida springs is warranted given demonstrable effects of nutrient enrichment in a broad suite of aquatic systems worldwide, the DO-grazer hypothesis and other potential mechanisms merit increased scientific scrutiny. This case study illustrates the importance of an adaptive approach that explicitly evaluates paradigms as hypotheses and actively seeks alternative explanations. PMID:20437966

Heffernan, James B; Liebowitz, Dina M; Frazer, Thomas K; Evans, Jason M; Cohen, Matthew J

2010-04-01

270

Haptophyte DNA and alkenone signatures during a spring algal bloom event in Lake George, ND, USA  

NASA Astrophysics Data System (ADS)

Lacustrine alkenone records have potential to be valuable sedimentary archives of continental paleotemperature. However, the use of the Uk37 paleotemperature proxy in lake environments is constrained by the genetic diversity of lake-dwelling, alkenone-producing haptophytes. Previous research in Lake George, ND revealed the presence of two alkenone-producing haptophyte species (Hap-A and Hap-B) whose individual contributions to the alkenone sediment record are unknown. To gauge the seasonal abundance of these multiple haptophyte species we used a high-throughput DNA sequencing approach. We collected bi-weekly water samples at three different depths in the photic zone (0m, 5m, 10m) from late April through bloom termination in early August. Using 18S rRNA gene sequences to determine species identity, we compared water sample microbial communities with water sample alkenone signatures. Additionally, we cultivated Lake George haptophyte isolates in pure and mixed cultures to define their Uk37 temperature calibrations. During the course of the seasonal cycle, total concentrations of alkenones demonstrated a distinct peak approximately five weeks after their first appearance in the water column. The peak bloom water samples were characterized by abundant tetraunsaturated (C37:4) alkenones in resemblance to the Lake George sediment records. As the bloom declined, the C37:4 alkenones declined in abundance. This variation in water column alkenone signature was reflected in the relative abundance of Hap-A and Hap-B, with Hap-B dominating during bloom peak. Our culture work determined that these multiple haptophyte isolates required individual Uk37 calibrations that differ from the Lake George in situ Uk37 calibration. Lake George sediment alkenone records are therefore composites of multiple, co-occurring haptophyte temperature records. This study is the first next-generation DNA sequencing effort to analyze the microbial community during a haptophyte bloom, and together with culture work, yields a comprehensive understanding of how alkenone signatures in the water column reflect variations in haptophyte species compositions. Our results showcase the genetic predestination of alkenone lipid production and the intricacies of competing temperature records in a lake environment.

Theroux, S.; Huang, Y.; Amaral-Zettler, L.

2012-12-01

271

Lagrangian Coherent Structures (LCS) and the dispersion of algal bloom and marine debris in the Yellow and East China Sea  

NASA Astrophysics Data System (ADS)

Series of satellite images show that the development and migration of green macroalgal bloom (known as Ulva prolifera) in the Yellow Sea (YS) and Eastern China Sea (ECS). This presentation will utilize the Lagrangian Coherent Structures (LCS) analysis to demonstrate the dispersion pattern of algal bloom patches. Analyzing LCS such as stable and unstable manifolds is one of emerging technologies for characterizing Lagrangian pathways in aquatic environments. This approach is based on the assumption that unstable manifolds such as ridges (i.e., high values) in the finite-time Lyapunov exponent (FTLE) fields coincide with material transport barriers. In this study, the FTLE fields were computed from gridded trajectories using flow fields provided by Regional Ocean Modeling System (ROMS) in the YS/ECS during summer 2011. The results show that there exist two strong transport barriers that lie along the east-west direction, at least, for the simulation period; one is located from the north of Changjiang River mouth to the middle of the Yellow Sea and the other one is stretched from the south of Shandong Peninsular toward east/southeast. This LCS analysis suggests that patches of green algae developed in the coastal region of Jiangsu Province during summer may migrate toward east into the middle of the YS or even toward Korean coast rather than extending along the Jiangsu coast, which is consistent with the observation results derived from the satellite ocean color data. In the very same manner, the utilization of LCS results to evaluate the distribution/transport pattern of marine debris in the YS/ECS will also be discussed during the presentation.

Kim, Y. H.; Choi, B.; Son, Y. B.; Shim, W. J.; Hwang, J. H.; Park, Y.

2012-12-01

272

Eutrophic waters, algal bloom and fish kill in fish farming areas in Bolinao, Pangasinan, Philippines.  

PubMed

The coastal waters of Bolinao, Pangasinan, Philippines experienced environmental changes over a 10-year period (1995-2005), the most significant effect of which was the major fish kill event in 2002 that coincided with the first reported Philippine bloom of a dinoflagellate Prorocentrum minimum. Days before the bloom, dissolved oxygen was < 2.0 mg/l in the waters that were stratified. These conditions may be linked to the uncontrolled proliferation of fish pens and cages to more than double the allowable limit of 544 units for Bolinao waters. Mariculture activities release organic matter from unconsumed feed and fecal material that accumulate in the water and sediments. In over 10 years, water quality conditions have become eutrophic with ammonia increasing by 56%, nitrite by 35%, nitrate by 90%, and phosphate by 67%. The addition of more fish pens and cages placed additional stress to this poorly flushed, shallow area that affected water quality due to changes in the water residence time. PMID:18456288

San Diego-McGlone, Maria Lourdes; Azanza, Rhodora V; Villanoy, Cesar L; Jacinto, Gil S

2008-01-01

273

Near surface temperature stratification and the on-shore transport of dense algal blooms  

NASA Astrophysics Data System (ADS)

Local hydrography is partially controlling the formation and maintenance of algae blooms. In the coastal upwelling off northern Baja California, Mexico, we frequently found a near surface temperature stratification (NSTS) that showed no definite mixed layer but discontinuities at about 2m depth indicating a near surface thermocline. We hypothesized that the density jump reduces significantly the frictional coupling supporting a more efficient wind transport of the top surface layer. Since during the day breezes in coastal upwelling areas are directed towards the coast, we propose that the NSTS will lead to a net transport of the top layer, with its dissolved and particulate constituents, towards the coast. During a surface bloom of the dinoflagellate Lingulodinium polyedrum (Sept-Oct 2011) we measured: i) the near surface stratification with a CTD profiler, ii) trajectories via GPS during daylight of CODE and Holey Sock type drifter buoys (drogued at either 1, 3, or 5m, each with thermistor at 1, 3 and 5 m), iii) wind speed and direction at a near-by meteorological station, and iv) velocity profiles via an Acoustic Doppler Current Profiler (Aquadopp-Nortek). The comparison of simultaneous ADCP's and drifters' data showed general agreement with noticeable shear close to the surface. The comparison of the two drifter types showed no significant difference. CTD profiles consistently presented near surface thermoclines between 2 and 4 m depth and temperature gradients in agreement with drifter thermistors. Chlorophyll a profiles showed the presence of high cell densities of L. polyedrum cells above 1.5 and 3.5 m depth. We found no increase in temperature at 1, 3 or 5 m during the deployment of the drifters suggesting that the NSTS is not strongly modulated during the day. No relationship between cells concentration-dependent light attenuation and temperature enhancement during the day was found. During the day drifter trajectories at 1 m moved towards the shore whereas drifters at 3 and 5m depth showed trajectories parallel or away from shore. These results are in agreement with the hypothesis that bloom forming organisms and other surface layer constituents will be efficiently transported towards shore during the day.

Ruiz-de la Torre, M.; Maske, H.; Ochoa-de-La-Torre, J. L.

2012-12-01

274

Tracking the algal origin of the Ulva bloom in the Yellow Sea by a combination of molecular, morphological and physiological analyses.  

PubMed

In 2008, Qingdao (36 degrees 06'N, 120 degrees 25'E, PR China) experienced the world largest drifting macroalgal bloom composed of the filamentous macroalga Ulva prolifera. No convincing biologic evidence regarding the algal source is available so far. A series of field collections of both Ulva sp. and waters in various sites along Jiangsu coasts were conducted in March to May of 2009. Density of microscopic Ulva germlings in the waters sampled from different sites ranged from 7 to 3140 individuals L(-1), indicating the wide-spreading and long-term existence of the algae in the investigated region. Morphological and the nuclear ribosomal internal transcribed spacer ITS nrDNA and the chloroplast-encoded rbcL gene comparisons of 26 algal samples revealed that the algae collected from land-based animal aquaculture ponds mostly resembled the dominating blooming alga in 2008. Mismatch of Porphyra farming period with the occurrence of the green tide bloom, as well as the negative identification results of the sampled green algae from the Porphyra rafts eliminated Porphyra rafts as the principal and original source of the dominating blooming alga. PMID:19896707

Pang, Shao Jun; Liu, Feng; Shan, Ti Feng; Xu, Na; Zhang, Zhi Huai; Gao, Su Qin; Chopin, Thierry; Sun, Song

2010-05-01

275

Cryptic Blooms: Are Thin Layers the Missing Connection?  

Microsoft Academic Search

Harmful algal blooms (HABs) are common in Monterey Bay, CA, and have resulted in repeated closures of shellfish fisheries\\u000a and the poisoning and death of marine mammals. In the majority of instances, HAB events in this region are first detected\\u000a by the presence of sick or dying animals. The phrase “cryptic blooms” was adopted to denote the appearance of poisoning

Margaret A. McManus; Raphael M. Kudela; Mary W. Silver; Grieg F. Steward; Percy L. Donaghay; James M. Sullivan

2008-01-01

276

Nutrients and toxin producing phytoplankton control algal blooms - a spatio-temporal study in a noisy environment.  

PubMed

A phytoplankton-zooplankton prey-predator model has been investigated for temporal, spatial and spatio-temporal dissipative pattern formation in a deterministic and noisy environment, respectively. The overall carrying capacity for the phytoplankton population depends on the nutrient level. The role of nutrient concentrations and toxin producing phytoplankton for controlling the algal blooms has been discussed. The local analysis yields a number of stationary and/or oscillatory regimes and their combinations. Correspondingly interesting is the spatio-temporal behaviour, modelled by stochastic reaction-diffusion equations. The present study also reveals the fact that the rate of toxin production by toxin producing phytoplankton (TPP) plays an important role for controlling oscillations in the plankton system. We also observe that different mortality functions of zooplankton due to TPP have significant influence in controlling oscillations, coexistence, survival or extinction of the zoo-plankton population. External noise can enhance the survival and spread of zooplankton that would go extinct in the deterministic system due to a high rate of toxin production. PMID:16388147

Sarkar, Ram Rup; Malchow, Horst

2005-12-01

277

Regulation of algal blooms in Antarctic Shelf Waters by the release of iron from melting sea ice  

NASA Astrophysics Data System (ADS)

During summer 1995-96, we measured iron in the water column and conducted iron-enrichment bottle-incubation experiments at a station in the central Ross Sea (76°30?S, 170°40?W), first, in the presence of melting sea ice, and 17 days later, in ice-free conditions. We observed a striking temporal change in mixed-layer dissolved iron concentrations at this station, from 0.72-2.3 nM with sea ice present, to 0.16-0.17 nM in ice-free conditions. These changes were accompanied by a significant drawdown in macronutrients and an approximate doubling of algal (diatom) biomass. Our incubation experiments suggest that conditions were iron-replete in the presence of sea ice, and iron-deficient in the absence of sea ice. We surmise that bioavailable iron was released into seawater from the melting sea ice, stimulating phytoplankton production and the biological removal of dissolved iron from the mixed layer, until iron-limited conditions developed. These observations suggest that the episodic release of bioavailable iron from melting sea ice is an important factor regulating phytoplankton production, particularly ice-edge blooms, in seasonally ice-covered Antarctic waters.

Sedwick, Peter N.; DiTullio, Giacomo R.

1997-10-01

278

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

279

Copepod grazing during spring blooms: Does Calanus pacificus avoid harmful diatoms?  

NASA Astrophysics Data System (ADS)

During late winter and spring of 2002 and 2003, 24, 2-3 day cruises were conducted to Dabob Bay, Washington State, USA, to examine the grazing, egg production, and hatching success rates of adult female Calanus pacificus and Pseudocalanus newmani. The results of the copepod grazing experiments for C. pacificus are discussed here. Each week, copepod grazing incubation experiments from two different depth layers were conducted. Grazing was measured by both changes in chlorophyll concentration and cell counts. In 2002, there was one moderate bloom consisting mainly of Thalassiosira spp. in early February, and a larger bloom in April comprised of two Chaetoceros species and Phaeocystis sp. Similarly, in 2003, there were two blooms, an early one dominated by Thalassiosira spp., and a later one consisting of Chaetoceros spp. and Thalassiosira spp. Clearance rates on individual prey species, as calculated by cell counts, showed that C. pacificus are highly selective in their feeding, and may have much higher clearance rates on individual taxa than rates calculated from bulk chlorophyll disappearance. During weeks of high phytoplankton concentration, the copepods generally ate phytoplankton. However, they often rejected the most abundant phytoplankton species, particularly certain Thalassiosira spp., even though the rejected prey were often of the same genus and similar size to the preferred prey. It is speculated that this avoidance may be related to the possible deleterious effects that certain of these diatom species have on the reproductive success of these copepods. During weeks of medium to low phytoplankton concentration, the copepods selectively ate certain species of phytoplankton, and often had high electivity for microzooplankton. The selection mechanism must consist of active particle rejection most likely based on detection of surface chemical properties, since the diatoms that were selected were of the same genus, nearly the same size, and at lower numerical abundance than those cells that were avoided. The grazing choices made by these copepods may have important consequences for the overall ecosystem function within coastal and estuarine systems through changes in the transfer efficiency of energy to higher trophic levels.

Leising, Andrew W.; Pierson, James J.; Halsband-Lenk, Claudia; Horner, Rita; Postel, James

2005-11-01

280

Remote sensing studies for the assessment of geohazards: Toxic algal blooms in the lower Great Lakes, and the land subsidence in the Nile Delta  

NASA Astrophysics Data System (ADS)

Remote sensing techniques provide valuable tools for assessing a wide variety of environmental phenomena. They have been used for monitoring and assessment of various types of geologic and environmental hazards occurring on land, in the air, or in oceans. I present results from two studies, the first of which examines the spatial and temporal distribution of algal blooms in the Great Lakes; the second measures subsidence in the Nile Delta. In the first study, methodologies to investigate the extent and distribution (temporally and spatially) of algal blooms in Lake Erie and Lake Ontario are studied. Millions of people in the U.S and Canada rely on the Great Lakes for drinking water, food, work, and recreation. Toxic algal blooms present a hazard to the substantial number of communities that draw water from the Great Lakes. Visible and infra red MODIS satellite data are used to map the extent of algal blooms in these lakes. Existing algorithms to retrieve chlorophyll concentrations are successfully tested against in situ measurements from sampling cruises. Algorithms are developed to identify the potentially toxic cyanobacterial blooms. The second study examines subsidence in the Nile Delta. The modern Nile Delta is the major agricultural production area for Egypt and was formed from sediments supplied by at least 10 distinct distributary channels throughout the Holocene. With an average elevation around a meter above sea level and with a predicted rise in sea level of 1.8--5.9 mm/year the subsidence of the northern 30 km of the delta is a topic of major concern to the Egyptian population and government. Ongoing subsidence rates in the northeastern Nile Delta were estimated using persistent scatterer radar interferometry techniques. The highest rates (˜8 mm/yr; twice average Holocene rates) correlate with the distribution of the youngest deposition, with older depositional centers subsiding at slower rates of 2--6 mm/yr. Results are interpreted to indicate that: (1) modern subsidence in the Delta is heavily influenced by the compaction of the most recent sediments, and (2) the highly threatened areas are at the terminus of the Damietta, where the most recent deposition has occurred.

Becker, Richard H.

281

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

Microsoft Academic Search

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

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

2007-01-01

282

EFFECTS OF CLAY USED TO CONTROL HARMFUL ALGAL BLOOMS, ON JUVENILE HARD CLAMS, MERCENARIA MERCENARIA. (R827090)  

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...

283

EFFECTS ON JUVENILE HARD CLAMS, MERCENARIA MERCENARIA, FROM THE APPLICATION OF PHOSPHATIC CLAYS TO MITIGATE HARMFUL ALGAL BLOOMS. (R827090)  

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...

284

Real-Time Behavioral Monitoring for Toxicity Caused by Harmful Algal Blooms and Other Water Quality Perturbations.  

National Technical Information Service (NTIS)

This a report of activities performed under a collaborative agreement between the U.S. Army Center for Environmental Health Research (USACEHR)and the University of Maryland Aquatic pathobiology Center (UM APC) These activities support the USACEHR. and the...

A. S. Kane E. K. Silbergeld R. Reimschuessel

2001-01-01

285

Molecular tools separate harmful algal bloom species, Karenia mikimotoi, from different geographical regions into distinct sub-groups  

Microsoft Academic Search

Karenia mikimotoi is a toxic dinoflagellate that is known to form extensive populations in the Eastern North Atlantic and Pacific Oceans that that impacts significantly on recreation and fisheries industries in these areas. Attempts to resolve the complex taxonomy within this “species” have been hampered by the requirement for fine-scale morphological analyses and by the lack of suitable genetic markers.

Manal A. Al-Kandari; Andrea C. Highfield; Matt J. Hall; Paul Hayes; Declan C. Schroeder

2011-01-01

286

National Harmful Algal Bloom Research and Monitoring Strategy: An Initial Focus on 'Pfiesteria', Fish Lesions, Fish Kills and Public Health.  

National Technical Information Service (NTIS)

In response to fish lesions, kills, Pfiesteria-like organisms, and possible threats to public health in the Mid-Atlantic region, the White House asked Federal agencies to develop and coordinate a long-term, national strategy for Federally-supported resear...

1997-01-01

287

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

288

Building a Bloom  

NSDL National Science Digital Library

This activity will help students understand algal blooms. They will devise their own experiments to test the effects of nutrients on algal growth, or younger students may follow the steps outlined in a sample activity which is provided. Students will be reminded that they need to have controls and replicates in their experiments. As a result of this activity, students will come to understand the requirements for algal growth, understand the factors that influence the occurrence and duration of algal blooms, and appreciate the diversity of algae in the marine environment.

289

Role of competition in phytoplankton population for the occurrence and control of plankton bloom in the presence of environmental fluctuations  

Microsoft Academic Search

Termination of harmful algal blooms (HABs) and coexistence of phytoplankton–zooplankton populations are of great importance to human health, ecosystem, environment, tourism and fisheries. In this paper, we propose a three component model consisting of non-toxic phytoplankton (NTP), toxin producing phytoplankton (TPP) and zooplankton (Z). The growth of zooplankton species is assume to reduce due to toxic chemicals released by TPP

S. Pal; Samrat Chatterjee; Krishna pada Das; J. Chattopadhyay

2009-01-01

290

In vitro interactions between several species of harmful algae and haemocytes of bivalve molluscs.  

PubMed

Harmful algal blooms (HABs) can have both lethal and sublethal impacts on shellfish. To understand the possible roles of haemocytes in bivalve immune responses to HABs and how the algae are affected by these cells (haemocytes), in vitro tests between cultured harmful algal species and haemocytes of the northern quahog (= hard clam) Mercenaria mercenaria, the soft-shell clam Mya arenaria, the eastern and Pacific oysters Crassostrea virginica and Crassostrea gigas and the Manila clam Ruditapes philippinarum were carried out. Within their respective ranges of distribution, these shellfish species can experience blooms of several HAB species, including Prorocentrum minimum, Heterosigma akashiwo, Alexandrium fundyense, Alexandrium minutum and Karenia spp.; thus, these algal species were chosen for testing. Possible differences in haemocyte variables attributable to harmful algae and also effects of haemolymph and haemocytes on the algae themselves were measured. Using microscopic and flow cytometric observations, changes were measured in haemocytes, including cell morphology, mortality, phagocytosis, adhesion and reactive oxygen species (ROS) production, as well as changes in the physiology and the characteristics of the algal cells, including mortality, size, internal complexity and chlorophyll fluorescence. These experiments suggest different effects of the several species of harmful algae upon bivalve haemocytes. Some harmful algae act as immunostimulants, whereas others are immunosuppressive. P. minimum appears to activate haemocytes, but the other harmful algal species tested seem to cause a suppression of immune functions, generally consisting of decreases in phagocytosis, production of ROS and cell adhesion and besides cause an increase in the percentage of dead haemocytes, which could be attributable to the action of chemical toxins. Microalgal cells exposed to shellfish haemolymph generally showed evidence of algal degradation, e.g. loss of chlorophyll fluorescence and modification of cell shape. Thus, in vitro tests allow a better understanding of the role of the haemocytes and the haemolymph in the defence mechanisms protecting molluscan shellfish from harmful algal cells and could also be further developed to estimate the effects of HABs on bivalve molluscs in vivo. PMID:21340660

Hégaret, Hélène; da Silva, Patricia Mirella; Wikfors, Gary H; Haberkorn, Hansy; Shumway, Sandra E; Soudant, Philippe

2011-08-01

291

Use of fuzzy logic models for prediction of taste and odor compounds in algal bloom-affected inland water bodies.  

PubMed

Mechanistic modeling of how algal species produce metabolites (e.g., taste and odor compounds geosmin and 2-methyl isoborneol (2-MIB)) as a biological response is currently not well understood. However, water managers and water utilities using these reservoirs often need methods for predicting metabolite production, so that appropriate water treatment procedures can be implemented. In this research, a heuristic approach using Adaptive Network-based Fuzzy Inference System (ANFIS) was developed to determine the underlying nonlinear and uncertain quantitative relationship between observed cyanobacterial metabolites (2-MIB and geosmin), various algal species, and physical and chemical variables. The model is proposed to be used in conjunction with numerical water quality models that can predict spatial-temporal distribution of flows, velocities, water quality parameters, and algal functional groups. The coupling of the proposed metabolite model with the numerical water quality models would assist various utilities which use mechanistic water quality models to also be able to predict distribution of taste and odor metabolites, especially when monitoring of metabolites is limited. The proposed metabolite model was developed and tested for the Eagle Creek Reservoir in Indiana (USA) using observations over a 3-year period (2008-2010). Results show that the developed models performed well for geosmin (R (2)?=?0.83 for all training data and R (2)?=?0.78 for validation of all 10 data points in the validation dataset) and reasonably well for the 2-MIB (R (2)?=?0.82 for all training data and R (2)?=?0.70 for 7 out of 10 data points in the validation dataset). PMID:24242080

Bruder, Slawa; Babbar-Sebens, Meghna; Tedesco, Lenore; Soyeux, Emmanuel

2014-03-01

292

MODIS and MERIS detection of dinoflagellates blooms using the RBD technique  

NASA Astrophysics Data System (ADS)

Harmful Algal Blooms (HABs) can lead to severe economical and ecological impacts particularly in the coastal areas and can threaten human and marine health. About three-quarter of these toxic blooms are caused by dinoflagellates species which are well known to migrate vertically. During the day, they migrate up to the surface for photosynthesis, and consequently, their dense aggregations produce strong bio-optical signals that are detectable by space borne optical satellite sensors. In this study we use our recently developed low backscattering bloom detection technique, the Red Band Difference (RBD), to detect various dinoflagellates blooms using both MODIS (Moderate Resolution Imaging Spectroradiometer) and MERIS (Medium Resolution Imaging Spectrometer) data and present the results which confirm the potentials of the RBD technique. Here we present examples of bloom detection in waters off Gulf of Mexico, Monterey Bay, South Africa, and East China Sea.

Amin, R.; Gilerson, A.; Gross, B.; Moshary, F.; Ahmed, S.

2009-09-01

293

[Discoloration of microalgal blooms as a bioindicating parameter in the Bahia de Mazatlán, México].  

PubMed

In order to verify whether harmful algal blooms increased since 1979, a long-term project for the study of harmful algal blooms in Mazatlán Bay began 25 years ago (1979-2003). Observations were done daily and results indicate five trend types: (I) years without discoloration related to El Niño events; (II) years with days of sudden occurrence of discoloration, related to the release of accumulated energy after El Niño events; (III) years with similar number of discoloration events (days); (IV) years with a progressive decrease of the occurrence (days) of discoloration events; (V) years with gradual increase of discoloration events. The annual mean average of discoloration is of 25.3 days. Ninety-six discoloration events were recorded during year 2000, and represent the highest number of events in the last 25 years. Discoloration events are more common in March (174 days), harmful and toxic blooms included. This indicates continuity in the occurrence of the highest content of microalgae, and therefore, it is concluded that they play an important role for a better understanding of the environmental deterioration undergone by the coastal zone due to an increase of harmful and toxic microalgae blooms. PMID:17465115

Cortés-Altamirano, Roberto; Licea-Durán, Sergio

2004-09-01

294

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.

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

295

A chemical approach for the mitigation of Prymnesium parvum blooms.  

PubMed

Known as Golden Algae in popular media, the harmful algal bloom causing organism Prymnesium parvum secretes increased amounts of toxic chemicals called prymnesins when stressed, resulting in major fish kills in Texas. Although many options exist for mitigation of blooms, a feasible protocol for control of blooms on large-scale impoundments has yet to be identified. Chemical control of P. parvum using six different enzyme inhibiting aquatic herbicides was explored in laboratory experiments. Of the six chemicals screened, one (flumioxazin) was selected for further study due to a significant decrease in P. parvum cell numbers with increasing chemical concentration. It was applied to natural plankton communities during in-situ experiments (Lake Granbury, Texas). The first experiment was conducted during a period of P. parvum bloom initiation (March) and the second experiment conducted during a post bloom period (April). Experiments were carried out in 20 L polycarbonate carboys covered in 30% shade cloth to simulate natural light, temperature and turbulence conditions. Through cell counts via light-microscopy, the chemical flumioxazin was found to cause significant decreases in P. parvum, but no significant differences in zooplankton abundance during the period of bloom initiation. However, significant decreases in adult copepods were observed during the post bloom period, with no significant decreases in P. parvum most likely due to decreased light penetration and inhibition of the photosensitive mode of action. PMID:22960102

Umphres, George D; Roelke, Daniel L; Netherland, Michael D

2012-12-01

296

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

297

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

298

First monospecific bloom of the harmful raphidophyte Chattonella antiqua (Hada) Ono in Alexandria waters related to water quality and copepod grazing  

Microsoft Academic Search

The massive red tide bloom of Chattonella antiqua that occurred in Alexandria waters during late August\\/early September 2006 was monospecific, of very high density, and of wide spatial distribution, and was accompanied by mass fish and invertebrates mortalities. During the bloom, surface water temperature ranged between 26.5 and 28.5 °C and salinity between 23 and 27 psu. The bloom started under very

Samia K. Mikhail

2007-01-01

299

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

300

A Review on Toxic and Harmful Algae in Greek Coastal Waters (E. Mediterranean Sea)  

PubMed Central

The Greek coastal waters are subjected to harmful algal bloom (HAB) phenomena due to the occurrence of species characterized as toxic (TX), potentially toxic (PT), and non-toxic, high biomass (HB) producers causing harm at multiple levels. The total number of (TX), (PT) and (HB) algae reported in this work are 61, but only 16 species have been associated with the occurrence of important HABs causing damage in the marine biota and the water quality. These phenomena are sporadic in time, space and recurrence of the causative species, and are related to the anthropogenically-induced eutrophication conditions prevailing in the investigated areas.

Ignatiades, Lydia; Gotsis-Skretas, Olympia

2010-01-01

301

Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics  

SciTech Connect

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 biochemical pathways that facilitate their dominance relative to other phytoplankton within specific environments have not been identified. Here, biogeochemical measurements demonstrated that the harmful alga Aureococcus anophagefferens outcompeted co-occurring phytoplankton in estuaries with elevated levels of dissolved organic matter and turbidity and low levels of dissolved inorganic nitrogen. We subsequently sequenced the first HAB genome (A. anophagefferens) and compared its gene complement to those of six competing phytoplankton species identified via metaproteomics. Using an ecogenomic approach, we specifically focused on the gene sets that may facilitate dominance within the environmental conditions present during blooms. A. anophagefferens possesses a larger genome (56 mbp) and more genes involved in light harvesting, organic carbon and nitrogen utilization, and encoding selenium- and metal-requiring enzymes than competing phytoplankton. Genes for the synthesis of microbial deterrents likely permit the proliferation of this species with reduced mortality losses during blooms. Collectively, these findings suggest that anthropogenic activities resulting in elevated levels of turbidity, organic matter, and metals have opened a niche within coastal ecosystems that ideally suits the unique genetic capacity of A. anophagefferens and thus has facilitated the proliferation of this and potentially other HABs.

Gobler, C J; Grigoriev, I V; Berry, D L; Dyhrman, S T; Wilhelm, S W; Salamov, A; Lobanov, A V; Zhang, Y; Collier, J L; Wurch, L L; Kustka, A B; Dill, B D; Shah, M; VerBerkomes, N C; Kuo, A; Terry, A; Pangilinan, J; Lindquist, E A; Lucas, S; Paulsen, I; Hattenrath-Lehmann, T K; Talmage, S; Walker, E A; Koch, F; Burson, A M; Marcoval, M A; Tang, Y; LeCleir, G R; Coyne, K J; Berg, G M; Bertrand, E M; Saito, M A; Gladyshev, V N

2011-03-02

302

Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics  

PubMed Central

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 biochemical pathways that facilitate their dominance relative to other phytoplankton within specific environments have not been identified. Here, biogeochemical measurements showed that the harmful alga Aureococcus anophagefferens outcompeted co-occurring phytoplankton in estuaries with elevated levels of dissolved organic matter and turbidity and low levels of dissolved inorganic nitrogen. We subsequently sequenced the genome of A. anophagefferens and compared its gene complement with those of six competing phytoplankton species identified through metaproteomics. Using an ecogenomic approach, we specifically focused on gene sets that may facilitate dominance within the environmental conditions present during blooms. A. anophagefferens possesses a larger genome (56 Mbp) and has more genes involved in light harvesting, organic carbon and nitrogen use, and encoding selenium- and metal-requiring enzymes than competing phytoplankton. Genes for the synthesis of microbial deterrents likely permit the proliferation of this species, with reduced mortality losses during blooms. Collectively, these findings suggest that anthropogenic activities resulting in elevated levels of turbidity, organic matter, and metals have opened a niche within coastal ecosystems that ideally suits the unique genetic capacity of A. anophagefferens and thus, has facilitated the proliferation of this and potentially other HABs.

Gobler, Christopher J.; Berry, Dianna L.; Dyhrman, Sonya T.; Wilhelm, Steven W.; Salamov, Asaf; Lobanov, Alexei V.; Zhang, Yan; Collier, Jackie L.; Wurch, Louie L.; Kustka, Adam B.; Dill, Brian D.; Shah, Manesh; VerBerkmoes, Nathan C.; Kuo, Alan; Terry, Astrid; Pangilinan, Jasmyn; Lindquist, Erika A.; Lucas, Susan; Paulsen, Ian T.; Hattenrath-Lehmann, Theresa K.; Talmage, Stephanie C.; Walker, Elyse A.; Koch, Florian; Burson, Amanda M.; Marcoval, Maria Alejandra; Tang, Ying-Zhong; LeCleir, Gary R.; Coyne, Kathryn J.; Berg, Gry M.; Bertrand, Erin M.; Saito, Mak A.; Gladyshev, Vadim N.; Grigoriev, Igor V.

2011-01-01

303

The influence of a toxic cyanobacterial bloom and water hydrology on algal populations and macroinvertebrate abundance in the upper littoral zone of Lake Krugersdrift, South Africa  

Microsoft Academic Search

The biological interactions and the physical and chemical properties of the littoral zone of Lake Krugersdrift were studied\\u000a for a 4-month period when a dense, toxic cyanobacterial bloom dominated by Microcystis aeruginosa was present in the main lake basin. The presence of a toxic strain of M. aeruginosa was confirmed through the use of ELISA and molecular markers that detect the presence

Paul J. Oberholster; Anna-Maria Botha; Peter J. Ashton

2009-01-01

304

Case study of phytoplankton blooms in serangoon harbor of Singapore  

Microsoft Academic Search

A recent algal bloom in the East Johor Strait has led to the damage of marine life in the water channel. This has lead to heavy economic losses to the fish farms located along the water channel. There is a desire to study and be able to predict the occurrences of algal blooms so that their effects on the fish

B. H. Ooi; H. Zheng; K. P. Yue; H. Kurniawati; P. Sundarambal; M. H. Dao; K. A. P. Roopsekhar; J. Wei; W. Cho; P. Tkalich; P. Malanotte-Rizzoli; N. M. Patrikalakis

2010-01-01

305

Strains of toxic and harmful microalgae, from waste water, marine, brackish and fresh water.  

PubMed

Some microalgae are economically important in Mexico and the world because they can be potentially toxic. Algal explosive population growths are named harmful algal blooms and are frequently recorded in Mexico. The authors set up potentially toxic microalgae cultures from the Gulf of Mexico (Garrapatas tideland, Barberena river, Carpintero lagoon in Tamaulipas State; Chalchoapan and Catemaco lakes in Veracruz State), from the Mexican Pacific Ocean, Guerrero, Colima and Michoacán States, and from interior water bodies such as Vicente Aguirre dam, Chapultepec lake and several waste water treatment plants. This research is about the diversity and abundance of phytoplankton in relation a specific site because of harmful algal bloom events. Microalgae cultures are useful in order to solve taxonomic problems, to know life cycles, molecular studies, for the study of toxic species, and the isolation of useful metabolites. The cultures for this research are clonal, non-axenic, semi-continuous, 12:12 light/dark photoperiod, 20 ± 1 °C temperature and 90.5 µmol m(-2)s(-1) illumination. Four different culture media were used. This collection is open to the worldwide scientific community as a source of organisms in controlled conditions that can be used as a useful tool for microalgae research work. PMID:21815840

Rodríguez-Palacio, M C; Crisóstomo-Vázquez, L; Alvarez-Hernández, S; Lozano-Ramírez, C

2012-01-01

306

Problems Related to Water Quality and Algal Control in Popez Reservoir, San Luis Obispo County, California.  

National Technical Information Service (NTIS)

Lopez Reservoir is used for flood control, water supply and recreation. Nuisance algal blooms have been a frequent occurrence in the reservoir since the first summer (1969) after filling. Dominant bloom species include the blue-green alga Anabaena unispor...

R. H. Fuller R. C. Averett W. G. Hines

1975-01-01

307

Laboratory study on the ecological impact of sophorolipid used for harmful algae elimination  

NASA Astrophysics Data System (ADS)

We studied the role of sophorolipid in inhibiting harmful algae bloom (HAB). Different sophorolipid concentrations were tested on marine microalgae, zooplankton, fish, and bivalve ( Mytilus edulis) in laboratory. The result shows that sophorolipid could inhibit the growth of algal species selectively. Among three algae species selected, Platymonas helgolandica var. tsingtaoensis was promoted with increasing sophorolipid concentration; Isochrysis galbana was inhibited seven days later in sophorolipid concentration below 40 mg/L; and Nitzschia closterium f. minutissima was inhibited obviously in only a high sophorolipid concentration over 20 mg/L. Therefore, sophorolipid in a low concentration at <20 mg/L could remove certain harmful algae species effectively without harming other non-harmful microalgae. For other animals, sophorolipid could inhibit the growth of ciliate Strombidium sp. by 50% at 20 mg/L sophorolipid concentration after 96 h. The concentration in 96-h LC50 for Calanus sinicus, Neomysis awatschensis, Lateolabrax japonicus, and Paralichthys olivaceus was 15, 150, 60, and 110 mg/L, respectively. The 24 h LC50 value for Artemia salina was 600 mg/L. The relative clearance rate of mussel Mytilus edulis decreased to 80%, 40%, and 20% of the control group after being exposed to 20, 50, and 100 mg/L sophorolipid for 24 h. Therefore, the toxicity for mitigation of harmful algae bloom at previously recommended concentration of 5-20 mg/L sophorolipid is low for most tested organisms in this reaserch.

Sun, Xiaoxia; Kim, Eunki; Sun, Song

2010-11-01

308

Relationship between land-use in the agro-forestry system of les Landes, nitrogen loading to and risk of macro-algal blooming in the Bassin d'Arcachon coastal lagoon (SW France)  

NASA Astrophysics Data System (ADS)

Nitrogen loading to the Bassin d'Arcachon coastal lagoon (SW France) was evaluated by studying land-use and nitrogen output in its 3001 km 2 catchment. At present, the catchment is dominated by forestry (79%), while intensive agriculture occupies 9% of the surface. The N-output of two hydrological subunits, i.e. the Tagon subunit dominated by pine forestry and the Arriou II subunit comprising both forestry and intensive agriculture, were monitored for a seven year period (1996-2002). From these observations it was calculated that forestry contributes on average 1.6 kg total N ha -1 yr -1, which is dominated by organic nitrogen (DON + PON are 70% of N). On an areal basis, intensive agriculture contributes 26 times more than forestry, i.e. 41.6 kg total N ha -1 yr -1, which is mainly in the form of nitrate (65% of N). These data were upscaled to the catchment and the upscaling was validated by comparison to gauged nitrogen throughputs for the catchment of the Leyre river that is the major tributary to the system. Taking into account the other known N sources and the interannual variability in the catchment it was estimated that nitrogen loading to the lagoon was on average 90 kg ha -1 yr -1 (range from 54 to 126 kg ha -1 yr -1). The sandy soils of the catchment have a clear potential for denitrification, but anoxic conditions (waterlogged) and input of organic matter to fuel this process are required. Currently, agricultural practices and spatial planning do not make use of this potential. Nitrogen loading in the Bassin d'Arcachon is reflected by 10-40 ?M nitrate concentrations in winter, which became depleted during spring as a result of uptake by vegetation. Short-term uptake experiments showed that the macroalga Monostroma obscurum is well adapted to temperatures between 10 to 20 °C and competitive with respect to the seagrass Zostera noltii when the nitrate concentrations are above 10 ?M. Spring conditions with high nitrate and high insolation are therefore favourable for M. obscurum and this species presents a high risk for algal blooming. In contrast, the macroalga Enteromorpha clathrata well adapted to summertime temperatures around 25 °C, forms occasionally blooms in the lagoon. This phenomenon is limited due to the low DIN concentrations in summer.

De Wit, R.; Leibreich, J.; Vernier, F.; Delmas, F.; Beuffe, H.; Maison, Ph.; Chossat, J.-C.; Laplace-Treyture, C.; Laplana, R.; Clavé, V.; Torre, M.; Auby, I.; Trut, G.; Maurer, D.; Capdeville, P.

2005-02-01

309

Harmful Algae Records in Venice Lagoon and in Po River Delta (Northern Adriatic Sea, Italy)  

PubMed Central

A detailed review of harmful algal blooms (HAB) in northern Adriatic Sea lagoons (Po River Delta and Venice lagoon) is presented to provide “updated reference conditions” for future research and monitoring activities. In the study areas, the high mollusc production requires the necessity to identify better methods able to prevent risks for human health and socioeconomical interests. So, an integrated approach for the identification and quantification of algal toxins is presented by combining microscopy techniques with Liquid Chromatography coupled with High Resolution Time of Flight Mass Spectrometry (HPLC-HR-TOF-MS). The method efficiency was first tested on some samples from the mentioned coastal areas, where Dinophysis spp. occurred during summer in the sites directly affected by seawaters. Although cell abundance was always <200?cells/L, the presence of Pectenotoxin-2 (PTX2), detected by HPLC-HR-TOF-MS, indicated the potential release of detectable amounts of toxins even at low cell abundance.

Bilanicova, Dagmar; Marcomini, Antonio

2014-01-01

310

Binational collaboration to study Gulf of Mexico's harmful algae  

NASA Astrophysics Data System (ADS)

Blooms of the toxic marine dinoflagellate Karenia brevis cause massive fish kills and other public health and economic problems in coastal waters throughout the Gulf of Mexico [Steidinger, 2009]. These harmful algal blooms (HABs) are a gulf-wide problem that require a synoptic observing system for better serving decision-making needs. The major nutrient sources that initiate and maintain these HABs and the possible connectivity of blooms in different locations are important questions being addressed through new collaborations between Mexican and U.S. researchers and government institutions. These efforts were originally organized under the U.S./Mexico binational partnership for the HABs Observing System (HABSOS), led by the U.S. Environmental Protection Agency's Gulf of Mexico Program (EPAGMP) and several agencies in Veracruz, Mexico, since 2006. In 2010 these efforts were expanded to include other Mexican states and institutions with the integrated assessment and management of the Gulf of Mexico Large Marine Ecosystem (GoMLME) program sponsored by the Global Environment Facility (GEF), the United Nations Industrial Development Organization (UNIDO), the Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT), and the National Oceanic and Atmospheric Administration (NOAA).

Soto, Inia; Hu, Chuanmin; Steidinger, Karen; Muller-Karger, Frank; Cannizzaro, Jennifer; Wolny, Jennifer; Cerdeira-Estrada, Sergio; Santamaria-del-Angel, Eduardo; Tafoya-del-Angel, Fausto; Alvarez-Torres, Porfirio; Herrera Silveira, Jorge; Allen, Jeanne

2012-01-01

311

Understanding harmful algae in stratified systems: Review of progress and future directions  

NASA Astrophysics Data System (ADS)

The Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB) program of the Scientific Committee on Oceanic Research (SCOR) and the Intergovernmental Oceanographic Commission (IOC) of UNESCO, was created in 1999 to foster research on the ecological and oceanographic mechanisms underlying the population dynamics of harmful algal blooms (HABs). The ultimate goal of this research is to develop observational systems and models that will eventually enable the prediction of HABs and thereby minimize their impact on marine ecosystems, human health and economic activities. In August of 2012, a workshop was held under the umbrella of the GEOHAB program at the Monterey Bay Aquarium Research Institute (MBARI). The over arching goal of this workshop was to review the current understanding of the processes governing the structure and dynamics of HABs in stratified systems, and to identify how best to couple physical/chemical and biological measurements at appropriate spatial and temporal scales to quantify the dynamics of HABs in these systems, paying particular attention to thin layers. This contribution provides a review of recent progress in the field of HAB research in stratified systems including thin layers, and identifies the gaps in knowledge that our scientific community should strive to understand in the next decade.

Berdalet, E.; McManus, M. A.; Ross, O. N.; Burchard, H.; Chavez, F. P.; Jaffe, J. S.; Jenkinson, I. R.; Kudela, R.; Lips, I.; Lips, U.; Lucas, A.; Rivas, D.; Ruiz-de la Torre, M. C.; Ryan, J.; Sullivan, J. M.; Yamazaki, H.

2014-03-01

312

Water management strategies against toxic Microcystis blooms in the Dutch delta.  

PubMed

To prevent flooding of the Dutch delta, former estuaries have been impounded by the building of dams and sluices. Some of these water bodies, however, experience major ecological problems. One of the problem areas is the former Volkerak estuary that was turned into a freshwater lake in 1987. From the early 1990s onward, toxic Microcystis blooms dominate the phytoplankton of the lake every summer. Two management strategies have been suggested to suppress these harmful algal blooms: flushing the lake with fresh water or reintroducing saline water into the lake. This study aims at an advance assessment of these strategies through the development of a mechanistic model of the population dynamics of Microcystis. To calibrate the model, we monitored the benthic and pelagic Microcystis populations in the lake during two years. Field samples of Microcystis were incubated in the laboratory to estimate growth and mortality rates as functions of light, temperature, and salinity. Recruitment and sedimentation rates were measured in the lake, using traps, to quantify benthic-pelagic coupling of the Microcystis populations. The model predicts that flushing with fresh water will suppress Microcystis blooms when the current flushing rate is sufficiently increased. Furthermore, the inlet of saline water will suppress Microcystis blooms for salinities exceeding 14 g/L. Both management options are technically feasible. Our study illustrates that quantitative ecological knowledge can be a helpful tool guiding large-scale water management. PMID:16705982

Verspagen, Jolanda M H; Passarge, Jutta; Jöhnk, Klaus D; Visser, Petra M; Peperzak, Louis; Boers, Paul; Laanbroek, Hendrikus J; Huisman, Jef

2006-02-01

313

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

314

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.

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

315

Improving Water Quality by Control of Algae: Biochemical Characterization of the Polysaccharides of Blue-Green Algae and Their Role in Bacterial-Algal.  

National Technical Information Service (NTIS)

The relationship between a model bloom species, Anabaena spiroides, and the bacteria naturally associated with the mucilaginous algal sheath were studied. The structural properties and biochemical composition of the algal extracellular polysaccharide were...

R. B. Wildman W. C. Wildman G. E. Rottinghause V. P. Cholvin

1979-01-01

316

Continuous automated imaging-in-flow cytometry for detection and early warning of Karenia brevis blooms in the Gulf of Mexico.  

PubMed

Monitoring programs for harmful algal blooms (HABs) typically rely on time-consuming manual methods for identification and enumeration of phytoplankton, which make it difficult to obtain results with sufficient temporal resolution for early warning. Continuous automated imaging-in-flow by the Imaging FlowCytobot (IFCB) deployed at Port Aransas, TX has provided early warnings of six HAB events. Here we describe the progress in automating this early warning system for blooms of Karenia brevis. In 2009, manual inspection of IFCB images in mid-August 2009 provided early warning for a Karenia bloom that developed in mid-September. Images from 2009 were used to develop an automated classifier that was employed in 2011. Successful implementation of automated file downloading, processing and image classification allowed results to be available within 4 h after collection and to be sent to state agency representatives by email for early warning of HABs. No human illness (neurotoxic shellfish poisoning) has resulted from these events. In contrast to the common assumption that Karenia blooms are near monospecific, post-bloom analysis of the time series revealed that Karenia cells comprised at most 60-75 % of the total microplankton. PMID:23307076

Campbell, Lisa; Henrichs, Darren W; Olson, Robert J; Sosik, Heidi M

2013-10-01

317

Effects of pulsed nutrient inputs on phytoplankton assemblage structure and blooms in an enclosed coastal area  

NASA Astrophysics Data System (ADS)

The response of phytoplankton assemblage structure to terrestrial nutrient inputs was examined for the Gulf of Kalloni in the Northern Aegean Sea, a productive semi-enclosed coastal marine ecosystem. The study was focused on a typical annual cycle, and emphasis was placed on the comparative analysis between blooms developing after significant nutrient inputs from the watershed, and naturally occurring blooms. Baseline information was collected on a monthly basis from a network of stations located in the oligotrophic open sea and the interior and more productive part of the embayment. Intensive sampling was also carried out along a gradient in the vicinity of a river which was the most important source of freshwater and nutrient input for the Gulf. Phytoplankton assemblage structure was analyzed from 188 samples using diversity indices (Shannon and Average Taxonomic Distinctness), multivariate plotting methods (NMDS), multivariate statistics (PERMANOVA), and canonical correspondence analysis (CCA). Three characteristic assemblages were recognized: (1) an autumn assemblage developed under nutrient depleted conditions, having low diversity due to the dominance of two small diatoms, (2) a winter bloom of the potentially toxic species Pseudo-nitzschia calliantha occurring immediately after a nutrient peak and characterized by very low diversity, and (3) a naturally occurring early summer bloom of centric diatoms with relatively high diversity. The results of the study support the view that moderate nutrient inputs may have a beneficial effect on the functioning of coastal ecosystems, stimulating the taxonomic diversity through the growth of different taxonomic groups and taxa. On the other hand, a sudden pulse of high nutrient concentrations may greatly affect the natural succession of organisms, have a negative effect on the diversity through the dominance of a single species, and can increase the possibility of a harmful algal bloom development.

Spatharis, Sofie; Tsirtsis, George; Danielidis, Daniel B.; Chi, Thang Do; Mouillot, David

2007-07-01

318

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

319

Toxic Blooms: Understanding Red Tides  

NSDL National Science Digital Library

This online seminar reviews the topic of red tides in four sessions, which review the effect HABs have on public health, wildlife and the economy; describe common harmful algal species and their toxins; identify poisoning symptoms; compare methods of treatment if poisoned; describe some potential methods to control HABs; and identify research areas where information on HABs is still inadequate. After completing the sessions, an optional knowledge test is provided based on the seminar material.

Anderson, Don; The Woods Hole Oceanographic Institution, Fathom

320

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

Microsoft Academic Search

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,

Fahad Alawadi

2010-01-01

321

Blooming Thermometers  

NSDL National Science Digital Library

In this activity, students develop an understanding of the relationship between natural phenomena, weather, and climate change: the study known as phenology. In addition, they learn how cultural events are tied to the timing of seasonal events. Students brainstorm annual natural phenomena that are tied to seasonal weather changes. Next, they receive information regarding the Japanese springtime festival of Hanami, celebrating the appearance of cherry blossoms. Students plot and interpret average bloom date data from over the past 1100 years.

Gardiner, Lisa; Al., Et; National Center for Atmospheric Research (NCAR)

322

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...

323

Population genetic structure and connectivity of the harmful dinoflagellate Alexandrium minutum in the Mediterranean Sea  

PubMed Central

The toxin-producing microbial species Alexandrium minutum has a wide distribution in the Mediterranean Sea and causes high biomass blooms with consequences on the environment, human health and coastal-related economic activities. Comprehension of algal genetic differences and associated connectivity is fundamental to understand the geographical scale of adaptation and dispersal pathways of harmful microalgal species. In the present study, we combine A. minutum population genetic analyses based on microsatellites with indirect connectivity (Ci) estimations derived from a general circulation model of the Mediterranean sea. Our results show that four major clusters of genetically homogeneous groups can be identified, loosely corresponding to four regional seas: Adriatic, Ionian, Tyrrhenian and Catalan. Each of the four clusters included a small fraction of mixed and allochthonous genotypes from other Mediterranean areas, but the assignment to one of the four clusters was sufficiently robust as proved by the high ancestry coefficient values displayed by most of the individuals (>84%). The population structure of A. minutum on this scale can be explained by microalgal dispersion following the main regional circulation patterns over successive generations. We hypothesize that limited connectivity among the A. minutum populations results in low gene flow but not in the erosion of variability within the population, as indicated by the high gene diversity values. This study represents a first and new integrated approach, combining both genetic and numerical methods, to characterize and interpret the population structure of a toxic microalgal species. This approach of characterizing genetic population structure and connectivity at a regional scale holds promise for the control and management of the harmful algal bloom events in the Mediterranean Sea.

Casabianca, Silvia; Penna, Antonella; Pecchioli, Elena; Jordi, Antoni; Basterretxea, Gotzon; Vernesi, Cristiano

2012-01-01

324

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

325

A simple approach for the efficient production of hydrogen from Taihu Lake Microcystis spp. blooms.  

PubMed

The death and subsequent decomposition of algal blooms is capable of depleting dissolved O2 to anaerobic levels, and this can de-inactivate hydrogenases. Inspired by this fact, a simple method for efficient H2 production from algal bloom biomass was developed. Direct transfer of Taihu Lake Microcystis spp. blooms into dark conditions resulted in H2 evolution, and yield was much greater than compared to Microcystis spp. cultured in the laboratory and reported previously in the literature. Further, efficient H2 production was inhibited significantly by light, which was most likely due to reduced O2 content and the stimulation of hydrogenase activity. Therefore, a simple approach for efficient H2 production from Taihu Lake Microcystis spp. blooms is presented. Furthermore, a post-treatment strategy for dealing with large quantities of refloated algal blooms is proposed. PMID:23648763

Wei, Lanzhen; Li, Xin; Yi, Jing; Yang, Zhou; Wang, Quanxi; Ma, Weimin

2013-07-01

326

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

327

Dynamics of a bloom of halophilic archaea in the Dead Sea  

Microsoft Academic Search

After a period of more than ten years in which bacterial and algal community sizes were extremely small, a dense bloom of halophilic archaea developed in the upper 5–10 m of the Dead Sea water column in the summer of 1992. The development of this bloom followed a dilution of the upper water layer by winter rainfloods, which enabled the

Aharon Oren; Peter Gurevich

1995-01-01

328

Satellite Detection of Phaeocystis Globosa Blooms in the Eastern English Channel  

Microsoft Academic Search

Detecting phytoplankton species from remote sensing is essential to map and monitor algal blooms in coastal waters, but stays a challenge because of the interference of suspended sediments and dissolved organic matter with the phytoplankton signal. In the eastern English Channel and the south North Sea, a more or less intensive bloom of prymnesiophyceae Phaeocystis globosa occurs almost every spring

B. Lubac; H. Loisel; A. Poteau; N. Guiselin

2006-01-01

329

Toxic and harmful marine phytoplankton and microalgae (HABs) in Mexican Coasts.  

PubMed

Harmful Algal Blooms (HABs) are becoming an increasing problem to human health and environment (including effects on natural and cultured resources, tourism and ecosystems) all over the world. In Mexico a number of human fatalities and important economic losses have occurred in the last 30 years because of these events. There are about 70 species of planktonic and non-planktonic microalgae considered harmful in Mexican coasts. The most important toxin-producing species are the dinoflagellates Gymnodinium catenatum and Pyrodinium bahamense var. compressum, in the Mexican Pacific, and Karenia brevis in the Gulf of Mexico, and consequently the poisonings documented in Mexico are Paralytic Shellfish Poisoning (PSP) and Neurotoxic Shellfish Poisoning (NSP). Although there is evidence that Amnesic Shellfish Poisoning (ASP), Diarrhetic Shellfish Poisoning (DSP) and Ciguatera Fish Poisoning (CFP) also occur in Mexico, these problems are reported less frequently. The type of phytoplankton and epiphytic microalgae, their toxins and harmful effects as well as current methodology used to study these phenomena are presented in this paper. As an experienced group of workers, we include descriptions of monitoring and mitigation programs, our proposals for collaborative projects and perspectives on future research. PMID:17680474

Hernández-Becerril, David U; Alonso-Rodríguez, Rosalba; Alvarez-Góngora, Cynthia; Barón-Campis, Sofia A; Ceballos-Corona, Gerardo; Herrera-Silveira, Jorge; Meave Del Castillo, María E; Juárez-Ruíz, Norma; Merino-Virgilio, Fanny; Morales-Blake, Alejandro; Ochoa, José L; Orellana-Cepeda, Elizabeth; Ramírez-Camarena, Casimiro; Rodríguez-Salvador, Raciel

2007-08-01

330

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

331

Are cyanobacterial blooms trophic dead ends?  

PubMed

Cyanobacterial blooms induce significant costs that are expected to increase in the near future. Cyanobacterial resistance to zooplankton grazing is one factor thought to promote bloom events. Yet, numerous studies on zooplankton ability to graze upon cyanobacteria have been producing contradictory results and such a puzzle might arise from the lack of direct observations in situ. Our objective was to track, using fatty acid (FA) and fatty acid stable isotope analyses (FA-SIA), the fate of cyanobacterial organic matter in the food web of a lake subjected to summer blooms of Planktothrix rubescens. A metalimnetic bloom of P. rubescens occurred in Lake Bourget (France) during the study period (May-November 2009). The bloom was especially rich in ?-linolenic acid, 18:3(n-3), but none of the considered zooplankton taxa exhibited spiking content in this particular FA. FA-SIA revealed, however, that over a quarter of 18:3(n-3) in small zooplankton (<500 ?m) was provided by P. rubescens while large cladocerans (>500 ?m) did not benefit from it. P. rubescens 18:3(n-3) could be tracked up to perch (Perca fluviatilis) young of the year (YOY) to which it contributed to ~15 % of total 18:3(n-3). Although transferred with a much lower efficiency than micro-algal organic matter, the P. rubescens bloom supported a significant share of the pelagic secondary production and did not constitute, sensu stricto, a 'trophic dead end'. The cyanobacterial bloom also provided perch YOY with components of high nutritional values at a season when these are critical for their recruitment. This cyanobacterial bloom might thus be regarded as a significant dietary bonus for juvenile fish. PMID:23129401

Perga, Marie-Elodie; Domaizon, Isabelle; Guillard, Jean; Hamelet, Valérie; Anneville, Orlane

2013-06-01

332

Structure-activity analysis of harmful algae inhibition by congeneric compounds: case studies of fatty acids and thiazolidinediones.  

PubMed

The occurrence of harmful algal blooms has been increasing significantly around the world. In order to ensure the safety of drinking water, procedures to screen potential materials as effective algicides are needed, and predictive methods which save both the labor and time compared with traditional experimental approaches, are particularly desirable. In this study, data from previous studies on the algal-growth inhibitory action of two kinds of compounds, namely, the action of fatty acids and thiazolidinediones on the harmful algae Heterosigma akashiwo and Chattonella marina, were modeled using multiple linear regression (MLR) based on quantitative structure-activity relationships (QSAR). The models were shown to have highly predictive ability and stability, and provided insight into the inhibitory mechanisms of congeneric compounds. The main descriptors in the fatty-acid models were the Connolly accessible area and the number of rotatable bonds, illustrating that molecular surface area and shape are important in their algicidal actions. In the thiazolidinedione models, the critical volume, octanol-water partition coefficient (LogP), and Connolly solvent-excluded volume were found to be significant, indicating that hydrophobicity, substituent group size, and mode of action are mechanistically important. Our results showed the algicidal activity of a series of compounds on different algae could be modeled, and each model is efficacious for compounds that fall into the application domain of the QSAR model. This work demonstrates how reliable predictions of the algicidal activity of novel compounds and explanations of their inhibitory mechanisms can be obtained. PMID:24562453

Huang, Haomin; Xiao, Xi; Shi, Jiyan; Chen, Yingxu

2014-06-01

333

Substrate-controlled succession of marine bacterioplankton populations induced by a phytoplankton bloom.  

PubMed

Phytoplankton blooms characterize temperate ocean margin zones in spring. We investigated the bacterioplankton response to a diatom bloom in the North Sea and observed a dynamic succession of populations at genus-level resolution. Taxonomically distinct expressions of carbohydrate-active enzymes (transporters; in particular, TonB-dependent transporters) and phosphate acquisition strategies were found, indicating that distinct populations of Bacteroidetes, Gammaproteobacteria, and Alphaproteobacteria are specialized for successive decomposition of algal-derived organic matter. Our results suggest that algal substrate availability provided a series of ecological niches in which specialized populations could bloom. This reveals how planktonic species, despite their seemingly homogeneous habitat, can evade extinction by direct competition. PMID:22556258

Teeling, Hanno; Fuchs, Bernhard M; Becher, Dörte; Klockow, Christine; Gardebrecht, Antje; Bennke, Christin M; Kassabgy, Mariette; Huang, Sixing; Mann, Alexander J; Waldmann, Jost; Weber, Marc; Klindworth, Anna; Otto, Andreas; Lange, Jana; Bernhardt, Jörg; Reinsch, Christine; Hecker, Michael; Peplies, Jörg; Bockelmann, Frank D; Callies, Ulrich; Gerdts, Gunnar; Wichels, Antje; Wiltshire, Karen H; Glöckner, Frank Oliver; Schweder, Thomas; Amann, Rudolf

2012-05-01

334

Review: advances in electrochemical genosensors-based methods for monitoring blooms of toxic algae.  

PubMed

Harmful algal blooms (HABs), which have expanded worldwide in their occurrence and frequency, are a serious menace to aquatic ecosystems and humans. The development of rapid, accurate and cost-effective detection systems for toxic algal monitoring in aquatic environments is urgently required. Although many efforts have been devoted to develop reliable tools to monitor the entire spectrum of existing toxic algae, a portable semi-automated system that enables HAB monitoring at a low cost is still not available for general purchase. This work reviews the challenges and opportunities in translating the remarkable progress of electrochemical genosensors-based methods towards practical in situ HAB monitoring applications. It is specifically focused on reviewing the optimised methods for a detection system based on a sandwich hybridisation assay (SHA) performed over transducer platforms of different materials, geometries and dimensions and presenting the diverse advantages and disadvantages among them. Probe design and specificity and optimisation of the genosensor in terms of hybridisation conditions and electrochemical signal are discussed as well as their long-term stability and storage and semi-automation attempts. With continuous innovation and attention to key challenges, we expect semi-automatic devices containing DNA-based electrochemical biosensors to have an important impact upon monitoring of serious HAB events. PMID:23097073

Orozco, Jahir; Medlin, Linda K

2013-10-01

335

Bloom syndrome.  

PubMed

Bloom Syndrome (BS, MIM #210900) is an autosomal recessive genetic disorder caused by a mutation in the BLM gene, which codes for the DNA repair enzyme RecQL3 helicase. Without proper DNA repair mechanisms, abnormal DNA exchange takes place between sister chromatids and results in genetic instability that may lead to cancer, especially lymphoma and acute myelogenous leukemia, lower and upper gastrointestinal tract neoplasias, cutaneous tumors, and neoplasias in the genitalia and urinary tract. BS patients are usually of Ashkenazi Jewish descent and exhibit narrow facial features, elongated limbs, and several dermatologic complications including photosensitivity, poikiloderma, and telangiectatic erythema. The most concerning manifestation of BS is multiple malignancies, which require frequent screenings and strict vigilance by the physician. Therefore, distinguishing between BS and other dermatologic syndromes of similar presentation such as Rothmund-Thomson Syndrome, Erythropoietic Protoporphyria, and Cockayne Syndrome is paramount to disease management and to prolonging life. BS can be diagnosed through a variety of DNA sequencing methods, and genetic testing is available for high-risk populations. This review consolidates several sources on BS sequelae and aims to suggest the importance of differentiating BS from other dermatologic conditions. This paper also elucidates the recently discovered BRAFT and FANCM protein complexes that link BS and Fanconi anemia. PMID:24602044

Arora, Harleen; Chacon, Anna H; Choudhary, Sonal; McLeod, Michael P; Meshkov, Lauren; Nouri, Keyvan; Izakovic, Jan

2014-07-01

336

Remote sensing as a tool for monitoring water quality parameters for Mediterranean Lakes of European Union water framework directive (WFD) and as a system of surveillance of cyanobacterial harmful algae blooms (SCyanoHABs).  

PubMed

Remote sensing has been used from the 1980s to study inland water quality. However, it was not until the beginning of the twenty-first century that CHRIS (an experimental multi-angle sensor with good spectral and spatial resolutions) and MERIS (with good temporal and spectral resolutions) started to acquire imagery with very good resolutions, which allowed to develop a reliable imagery acquisition system so as to consider remote sensing as an inland water management tool. This paper presents the methodology developed, from the field data acquisition with which to build a freshwater spectral library and the study of different atmospheric correction systems for CHRIS mode 2 and MERIS images, to the development of algorithms to determine chlorophyll-a and phycocyanin concentrations and bloom sites. All these algorithms allow determining water eutrophic and ecological states, apart from generating surveillance maps of toxic cyanobacteria with the main objective of Assessment of the Water Quality as it was used for Monitoring Ecological Water Quality in smallest Mediterranean Reservoirs integrated in the Intercalibration Exercise of European Union Water Framework Directive (WFD). We keep on using it to monitor the Ecological Quality Ratio (EQR) in Spain inland water. PMID:21243424

Gómez, José Antonio Domínguez; Alonso, Covadonga Alonso; García, Ana Alonso

2011-10-01

337

Initial observations of the 2005 Alexandrium fundyense bloom in southern New England: General patterns and mechanisms  

NASA Astrophysics Data System (ADS)

From May to July, 2005, an extensive bloom of Alexandrium fundyense occurred along the coast of southern New England. The outbreak eventually closed shellfish beds from central Maine to Massachusetts, including Nantucket Island and portions of Martha's Vineyard, and resulted in the closure of 40,000 km 2 of offshore federal waters as well. The coastal Alexandrium bloom was exceptional in several ways: high toxin levels were measured farther south than ever before in New England; levels of toxicity in many locations were higher than previously observed at those stations; for the first time toxicity at some locations was above quarantine levels; cell concentrations far exceeded those observed in the coastal waters of southern New England in the past; and for the first time in the region the governors of Maine and Massachusetts officially declared the red tide to be a disaster, clearing the way for federal assistance. Initial observations suggest that several factors contributed to this bloom. Abundant rainfall and heavy snowmelt substantially increased the amount of fresh water entering the Gulf of Maine. Combined with other freshwater inputs, we hypothesize that this provided macro- and micro-nutrients, a stratified water column, and a transport mechanism that led to high cell abundances and broad, region-wide dispersal of the organism. Warm temperatures in western waters also would have favored A. fundyense growth. In addition, several storms with strong winds out of the northeast occurred at times when cells were abundant and in locations where the winds could advect them into Massachusetts and Cape Cod Bays and keep them there, leading to high cell concentrations and toxicity. Another contributing factor may have been the high abundance of newly deposited cysts in western Gulf of Maine sediments, as documented in a fall 2004 survey. Here, we evaluate this bloom and the patterns of toxicity in light of the conceptual models for A. fundyense dynamics developed during the Ecology and Oceanography of Harmful Algal Blooms (ECOHAB)-Gulf of Maine (GOM) program. Several features of the 2005 bloom conform to the mechanisms proposed in those models, including the alongshore transport of cells in major water masses and episodic intrusions of cells toward shore due to downwelling-favorable wind forcings. The models need to be refined and expanded, however, based on new data and observations. For example, it is now clear that cells and bloom patches can reach the outer side of Cape Cod and even Nantucket and Martha's Vineyard. Transport to the coastal waters of Rhode Island and even Connecticut/Long Island is also possible. A critical modification also may be necessary in terms of mechanisms through which A. fundyense cells occur in Massachusetts Bay. In the past, toxicity only developed when blooms were transported from the north and into the bay via the western segment of the Maine Coastal Current. Now, it is possible that the bay might serve as a source of cells through the germination of cysts deposited in those waters during the 2005 bloom. If proven in subsequent surveys, this potential for in situ bloom development could have major implications on the timing and extent of toxicity within Massachusetts Bay and southern New England waters in future years.

Anderson, Donald M.; Keafer, Bruce A.; McGillicuddy, Dennis J.; Mickelson, Michael J.; Keay, Kenneth E.; Scott Libby, P.; Manning, James P.; Mayo, Charles A.; Whittaker, David K.; Michael Hickey, J.; He, Ruoying; Lynch, Daniel R.; Smith, Keston W.

2005-09-01

338

[Temporal-spatial distribution of algal cells during drought period in Daning River of Three Gorges].  

PubMed

In order to provide basic data for algal bloom warning system, the study on temporal-spatial distribution of algal cells was carried out in Daning River of Three Gorges form April to September, 2011. The results of temporal distribution were as follows: the dominant algal species were blue algal, green algal and diatom. During the test, the density proportion of blue algae increased continuously, the density proportion of diatom decreased, while the density proportion of green algae did not change significantly. The results of spatial distribution were as follows: algal density was extremely significantly correlated with water temperature and chlorophyll a (Chl a), the correlation coefficient were 0.97 and 0.95, respectively; algal density was significantly correlated with light intensity (LI), dissolved oxygen (DO), pH and dissoluble total phosphorus (DTP), the correlation coefficient were 0.87, 0.83, 082 and 0.82, respectively; the algal density in 0 m of Caziba was higher than those in other water depths, and in Baishuihe the highest algal density occurred at 2.0 m water depth in June and July, in Shuanglong most algal cells were found in 0 m and 2.0 m in July, August and September, in Dachang algal density in different water depth did not change significantly during the test; the proportion of different algal species in vertical direction was different in the test, probably because different algal species fitted different environments. PMID:23947029

Zhang, Yong-Sheng; Zheng, Bing-Hui; Wang, Kun; Jiang, Xia; Zheng, Hao

2013-06-01

339

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

340

Enhancement of algal growth and productivity by grazing zooplankton.  

PubMed

Colonies of the common planktonic green alga, Sphaerocystis schroeteri, are only partially disrupted and assimilated by Daphnia magna, a natural predator. The Daphnia break up the outer protective gelatinous sheath that surrounds Sphaerocystis colonies, but most of the algal cells emerge from Daphnia guts intact and in viable condition. During gut passage, these viable cells take up nutrients, such as phosphorus, both from algal remains and from Daphnia metabolites. This nutrient supply stimulates algal carbon fixation and cell division. Enhanced algal growth, observed after gut passage, can compensate for the minor losses to the population caused by grazing. Nutrients regenerated by grazers may produce the summer bloom of gelatinous green algae during the seasonal succession of lake phytoplankton. PMID:17739838

Porter, K G

1976-06-25

341

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.

Hong, Jiarong; Talapatra, Siddharth; Katz, Joseph; Tester, Patricia A.; Waggett, Rebecca J.; Place, Allen R.

2012-01-01

342

Why do cladocerans fail to control algal blooms?  

Microsoft Academic Search

Field studies show that even at high nutrient loads phytoplankton may be kept at low levels by filter-feeding zooplankton\\u000a for a period of weeks (spring clear water phase in lakes) or months (low-stocked fish-ponds). In the absence of planktivorous\\u000a fish, large-bodied cladocerans effectively control the abundance of algae of a broad size spectrum. Laboratory experiments\\u000a show that, although difficult to

Z. Maciej Gliwicz

1990-01-01

343

Marine ecologySpring algal bloom and larval fish survival  

Microsoft Academic Search

The different factors that influence the prevalent decline in fish stocks are currently subject to urgent and intense scrutiny. Here we combine the use of remote-sensing satellite data with a long-term data set of haddock recruitment off the eastern continental shelf of Nova Scotia, Canada, to show that the survival of the larval fish depends on the timing of the

Trevor Platt; Csar Fuentes-Yaco; Kenneth T. Frank

2003-01-01

344

Nutrient limitation and algal blooms in urbanizing tidal creeks  

Microsoft Academic Search

Tidal creeks are commonly found in low energy systems on the East and Gulf Coasts of the United States, and are often subject to intense watershed human development. Many of these creeks are receiving urban and suburban runoff containing nutrients, among other pollutants. During the period 1993–2001, we studied three tidal creeks located in southeastern North Carolina, a rapidly urbanizing

Michael A. Mallin; Douglas C. Parsons; Virginia L. Johnson; Matthew R. McIver; Heather A. CoVan

2004-01-01

345

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

346

Harmful cyanobacterial toxic blooms in waste stabilization ponds  

Microsoft Academic Search

A coccoid picocyanobacterium Synechocystis sp. (0.6-2 µm of cell diameter) was found to be dominant during summer period in the experimental wastewater stabilisation pond of Marrakesh. The taxono- my of this isolated strain was confirmed by electron microscope study. The general patterns of ultrastructure and the mode of cell division resemble Chroococcales. The cyanobacterium strain was axenic and cultured on

B. Oudra; M. El Andaloussi; S. Franca; P. Barros; R. Martins; K. Oufdou; B. Sbiyyaa; M. Loudiki; N. Mezrioui; V. Vasconcelos

2000-01-01

347

Brevetoxicosis in seabirds naturally exposed to Karenia brevis blooms along the central west coast of Florida.  

PubMed

Harmful algal bloom events caused by the dinoflagellate Karenia brevis occurred along the central west Florida, USA, coast from February 2005 through December 2005 and from August 2006 through December 2006. During these events, from 4 February 2005 through 28 November 2006, live, debilitated seabirds admitted for rehabilitation showed clinical signs that included disorientation, inability to stand, ataxia, and seizures. Testing of blood, biologic fluids, and tissues for brevetoxin by enzyme-linked immunosorbent assay found toxin present in 69% (n=95) of rehabilitating seabirds. Twelve of the 19 species of birds had evidence of brevetoxin exposure. Commonly affected species included Double-crested Cormorants (Phalacrocorax auritus), Brown Pelicans (Pelecanus occidentalis), Great Blue Herons (Ardea herodias), and Common Loons (Gavia immer). Serial blood and fecal samples taken from several live seabirds during rehabilitation showed that brevetoxin was cleared within 5-10 days after being admitted to the rehabilitation facility, depending on the species tested. Among seabirds that died or were euthanized, the highest brevetoxin concentrations were found in bile, stomach contents, and liver. Most dead birds had no significant pathologic findings at necropsy, thereby supporting brevetoxin-related mortality. PMID:23568900

Fauquier, Deborah A; Flewelling, Leanne J; Maucher, Jennifer M; Keller, Martha; Kinsel, Michael J; Johnson, Christine K; Henry, Michael; Gannon, Janet G; Ramsdell, John S; Landsberg, Jan H

2013-04-01

348

A niche model to predict Microcystis bloom decline in Chaohu Lake, China  

NASA Astrophysics Data System (ADS)

Cyanobacterial blooms occur frequently in lakes due to eutrophication. Although a number of models have been proposed to forecast algal blooms, a good and applicable method is still lacking. This study explored a simple and effective mathematical-ecological model to evaluate the growth status and predict the population dynamics of Microcystis blooms. In this study, phytoplankton were collected and identified from 8 sampling sites in Chaohu Lake every month from July to October, 2010. The niche breadth and niche overlap of common species were calculated using standard equations, and the potential relative growth rates of Microcystis were calculated as a weighted-value of niche overlap. In July, the potential relative growth rate was 2.79 (a.u., arbitrary units) but then rapidly declined in the following months to -3.99 a.u. in September. A significant correlation ( R =0.998, P <0.01) was found in the model between the net-increase in biomass of Microcystis in the field and the predicted values calculated by the niche model, we concluded that the niche model is suitable for forecasting the dynamics of Microcystis blooms. Redundancy analysis indicated that decreases in water temperature, dissolved oxygen and total dissolved phosphorus might be major factors underlying bloom decline. Based on the theory of community succession being caused by resource competition, the growth and decline of blooms can be predicted from a community structure. This may provide a basis for early warning and control of algal blooms.

Wang, Zhicong; Li, Zhongjie; Li, Dunhai

2012-07-01

349

North Pacific Bloom  

NASA Technical Reports Server (NTRS)

Many images are made of relatively bright phytoplankton blooms. However, not all such blooms reflect more light than they absorb. SeaWiFS collected this image of a patch in the north Pacific that had been darkened because the photosynthetic pigments of the phytoplankton living there had absorbed more of the incoming solar radiation than the relatively phytoplankton-poor surrounding waters. The Hawaiian islands can be seen through the clouds about 1000 kilometers to the southwest of the patch.

2002-01-01

350

[Extinguishment of harmful algae by organo-clay].  

PubMed

Periodic and widespread algal blooms have caused a variety of problems for aquatic life and human activity throughout the world. Currently, the only remedial practice employed for removing algal blooms is to spread clay on the surface of the water. But, the algal removal efficiency by the crude minerals are not really ideal, and how to improve the capability of clays to remove algae is now the technological focus, which also is fatal to the practical value of clays. In this study, hexadecyltrimethyleamine bromide (HDTMAB), one kind of cationic organo-surfactants, was chosen to improve kaolin by surface sorption and cationic exchange, and was tested to remove Prorocentrum donghaiense, a red tide organism in Donghai Sea. The results indicated that organo-clay had an excellent ability to extinguish red tide organisms, even under the application of 0.01 g.L-1, and could subside more than 95% red tide organisms in 24 h. The efficient algae removal by organo-clay might be from the reversal of the surface electric charge on clay particles, the "net capture" by the long lipoid chains of HDTMAB, and the local high density of HDTMAB on particles surface, which could effectively kill algal cells. PMID:14587345

Cao, Xihua; Yu, Zhiming

2003-07-01

351

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

352

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 ...

353

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

354

Growth characteristics of algae during early stages of phytoplankton bloom in Lake Taihu, China.  

PubMed

Three treatments, sediment plus lake water (S+W), sterilized sediment plus lake water (SS+W), and sediment plus filtered lake water (S+FW), were recruited to investigate the growth characteristics of algae during pre-bloom and the importance of algal inocula in the water column and sediment. The results showed that in the water column, biomass of all algae increased in all treatments when recruitment was initiated, whereas this tendency differed among treatments with further increment of temperature. The process of algal growth consisted of two stages: Stage I, the onset of recruitment and Stage II, the subsequent growth of algae. Compared with S+W, in Stage I, SS+W significantly increased the biomass of cyanophytes by 178.70%, and decreased the biomass of non-cyanophytes by 43.40%; In Stage II, SS+W notably stimulated the growth of all algae, thus incurring the occurrence of phytoplankton bloom. Further analyses revealed that both metabolic activity and photochemical activity of algae were enhanced in SS+W, which resulted from the releasing of nutrients from sediment. These results suggest that algal growth in Stage II and algal inocula in the water column can be important factors for the formation of phytoplankton bloom. In addition, possible mechanisms promoting algal recruitment and subsequent growth of algae were explored. PMID:23596943

Jia, Yuhong; Dan, Johnson; Zhang, Min; Kong, Fanxiang

2013-02-01

355

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

356

Problems related to water quality and algal control in Lopez Reservoir, San Luis Obispo County, California  

USGS Publications Warehouse

A study to determine the present enrichment status of Liopez Reservoir in San Luis Obispo county, California, and to evaluate copper sulfate algal treatment found that stratification in the reservoir regulates nutrient release and that algal control has been ineffective. Nuisance algal blooms, particularly from March to June, have been a problem in the warm multipurpose reservoir since it was initially filled following intense storms in 1968-69. The cyanophyte Anabaena unispora has been dominant; cospecies are the diatoms Stephanodiscus astraea and Cyclotella operculata, and the chlorophytes Pediastrum deplex and Sphaerocystis schroeteri. During an A. unispora bloom in May 1972 the total lake surface cell count was nearly 100,000 cells/ml. Thermal stratification from late spring through autumn results in oxygen deficiency in the hypolimnion and metalimnion caused by bacterial oxidation of organic detritus. The anaerobic conditions favor chemical reduction of organic matter, which constitute 10-14% of the sediment. As algae die, sink to the bottom, and decompose, nutrients are released to the hypolimnion , and with the autumn overturn are spread to the epilimnion. Algal blooms not only hamper recreation, but through depletion of dissolved oxygen in the epilimnion may have caused periodic fishkills. Copper sulfate mixed with sodium citrate and applied at 1.10-1.73 lbs/acre has not significantly reduced algal growth; a method for determining correct dosage is presented. (Lynch-Wisconsin)

Fuller, Richard H.; Averett, Robert C.; Hines, Walter G.

1975-01-01

357

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

358

West Coast Chlorophyll Bloom  

NSDL National Science Digital Library

Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on board the Orbview 2 satellite captured the phytoplankton bloom October 6, 2002 . Red represents high concentration of chlorophyll, follow by orange, yellow and green. Land and cloud portions of the image are presented in natural color. SeaWiFS monitors ocean plant life by measuring the amount of chlorophyll in the ocean. Large phytoplankton blooms tend to coincide with natural phenomena that drive that nutrient-rich water to the surface. The process is called upwelling. Winds coming off principal land masses push surface layers of water away from the shore. Into the resulting wind-driven void deeper water underneath the surface layers rushes in toward the coast, bringing with it nutrients for life to bloom. This upwelling fuel the growth of marine phytoplankton which, along with larger seaweeds, nourishes the incredible diversity of creatures found along the northern and central California coast.

Perkins, Lori; Feldman, Gene

2002-10-15

359

Nodularin uptake by seafood during a cyanobacterial bloom.  

PubMed

The problem of blue-green algal toxin contamination of recreational waters and drinking water catchments is well described, as is the potential contamination of associated seafood. Algal contamination of Victorian waterways is now a widespread annual occurrence and, in some regions, the intersection of blooms and commercial fishing threatens the food safety of large numbers of people. Toxin levels which produce no observed adverse effect in animal studies were used to derive safe tolerable daily intake levels. These 'acceptable levels' were then modified to protect against potential acute health risks associated with short-term exposures. National food surveys were used to derive likely seafood intakes and thus, in combination with 'safe toxin levels', health alert levels for seafood were formulated. During the summer of 2001 a bloom of Nodularia spumigena occurred in the Gippsland Lakes area of Southern Victoria. During the bloom, seafood samples were collected and nodularin concentrations were estimated. Nodularin concentrations reached levels of concern in mussels and in prawn viscera at cell counts as low as 30,000 cells/ml. Nodularin concentrations in the flesh of finfish remained low. Boiling the seafood redistributed toxin between viscera and flesh. The results were used to restrict some seafood harvesting. PMID:11769243

Van Buynder, P G; Oughtred, T; Kirkby, B; Phillips, S; Eaglesham, G; Thomas, K; Burch, M

2001-01-01

360

Are algal communities driven toward maximum biomass?  

PubMed Central

In this continental-scale study, we show that in major benthic and planktonic stream habitats, algal biovolume—a proxy measure of biomass—is a unimodal function of species richness (SR). The biovolume peak is observed at intermediate to high SR in the benthos but at low richness in the phytoplankton. The unimodal nature of the biomass–diversity relationship implies that a decline in algal biomass with potential harmful effects on all higher trophic levels, from invertebrates to fish, can result from either excessive species gain or species loss, both being common consequences of human-induced habitat alterations. SR frequency distributions indicate that the most frequent richness is habitat-specific and significantly higher in the benthos than in the plankton. In all studied stream environments, the most frequent SR is lower than the SR that yields the highest biovolume, probably as a result of anthropogenic influences, but always within one standard deviation from it, i.e. they are statistically indistinguishable. This suggests that algal communities may be driven toward maximum biomass.

Passy, Sophia I; Legendre, Pierre

2006-01-01

361

[Vertical migration of algal cells in the Daning River Bay of the Three Gorges Reservoir].  

PubMed

To support the basic data for forecast of algal blooms, circadian vertical migration experiment was carried out in the Daning River Bay of the Three Gorges Reservoir in July, 2011. The results were as follows: in this period, different algal species were found in the Daning River Bay, including cyanobacteria, green algae, dinoflagellates and diatoms etc; the distribution of algal cells was uneven, 72.5%-76.2% of algal cells aggregated at 0.5-4.0 m water depths from 10:00 AM to 10:00 AM next day, but 7.5%-16.3% of algal cells aggregated at 0-0.5 m. Morisita's indexes (MI) of algal cells were from 1.41 to 1.97 in day time, and from 1.17 to 1.55 at night. Morisita's indexes of chlorophyll a(Chla)were from 1.31 to 1.59 in day time, and from 1.17 to 1.39 at night. The vertical migration also occurred at 0.5-4.0 m water depths. The algal density was not significantly related with the concentrations of nutrient except that of dissolved total phosphorus (DTP) (r = 0.89). The algal density was also influenced by water temperature (WT), pH and specific conductance (SPC), and the correlation coefficients were 0.96, 0.97 and -0.99, respectively. PMID:23323407

Zhang, Yong-Sheng; Zheng, Bing-Hui; Jiang, Xia; Zheng, Hao; Zhong, Na; Chen, Chun-Xiao

2012-11-01

362

Improving the Algae Bloom Prediction through the Assimilation of the Remotely Sensed Chlorophyll-A Data in a Generic Ecological Model in the North Sea  

NASA Astrophysics Data System (ADS)

Harmful algae can cause damage to co-existing organisms, tourism and farmers. Accurate predictions of algal future composition and abundance as well as when and where algal blooms may occur could help early warning and mitigating. The Generic Ecological Model, GEM, [Blauw et al 2008] is an instrument that can be applied to any water system (fresh, transitional or coastal) to calculate the primary production, chlorophyll-a concentration and phytoplankton species composition. It consists of physical, chemical and ecological model components which are coupled together to build one generic and flexible modeling tool. For the North Sea, the model has been analyzed to assess sensitivity of the simulated chlorophyll-a concentration to a subset of ecologically significant set of factors. The research led to the definition of the most significant set of parameters to the algae blooming process in the North Sea [Salacinska et al 2009]. In order to improve the prediction of the model, the set of parameters and the chlorophyll-a concentration can be further estimated through the use of data assimilation. In this research, the Ensemble Kalman Filter (EnKF) data assimilation technique is used to assimilate the chlorophyll-a data of the North Sea, retrieved from MEdium Resolution Imaging Sensor (MERIS) spectrometer data [Peters et al 2005], in the GEM model. The chlorophyll-a data includes concentrations and error information that enable their use in data assimilation. For the same purpose, the uncertainty of the ecological generic model, GEM has been quantified by means of Monte Carlo approach. Through a study covering the year of 2003, the research demonstrates that both data and model are sufficiently robust for a successful assimilation. The results show that through the assimilation of the satellite data, a better description of the algae bloom has been achieved and an improvement of the capability of the model to predict the algae bloom for the North Sea has been confirmed. Blauw A.N., Los F.J., Bokhorst M., Erftemeijer P.L.A., (2009), GEM: a Generic Ecological Model for estuaries and coastal waters. Journal of Hydrobiologia, Volume 618, Number 1, 175-198. Peters, S.W.M., Eleveld, M. Pasterkamp, R., Woerd, H. van der, Devolder, M., Jans, S., Park, Y., Ruddick, K., Block, T., Brockmann, C., Doerffer, R., Krasemann, H., Röttgers, R., Schönfeld, W., Jørgensen, P.V., Tilstone, G., Martinez-Vicente, V., Moore, G., Sørensen, K., Høkedal, J., Johnsen, T.M., Lømsland, E.R., Aas, E. (2005). Atlas of Chlorophyll-a concentration for the North Sea based on MERIS imagery of 2003. IVM report, Vrije Universiteit Amsterdam, 117 pp. ISBN 90-5192-026-1. Salacinska K., El Serafy G.Y., Blauw A., Los F.J., (2009) Sensitivity analysis of the two dimensional application of the Generic Ecological Model (GEM) to algal bloom prediction in the North Sea, Journal of Ecological Modeling, volume 221, 7, pp 178-190, DOI: 10.1016/j.ecolmodel.2009.10.001

El Serafy, Ghada

2010-05-01

363

Anomalous rise in algal production linked to lakewater calcium decline through food web interactions  

PubMed Central

Increased algal blooms are a threat to aquatic ecosystems worldwide, although the combined effects of multiple stressors make it difficult to determine the underlying causes. We explore whether changes in trophic interactions in response to declining calcium (Ca) concentrations, a water quality issue only recently recognized in Europe and North America, can be linked with unexplained bloom production. Using a palaeolimnological approach analysing the remains of Cladocera (herbivorous grazers) and visual reflectance spectroscopically inferred chlorophyll a from the sediments of a Nova Scotia (Canada) lake, we show that a keystone grazer, Daphnia, declined in the early 1990s and was replaced by a less effective grazer, Bosmina, while inferred chlorophyll a levels tripled at constant total phosphorus (TP) concentrations. The decline in Daphnia cannot be attributed to changes in pH, thermal stratification or predation, but instead is linked to declining lakewater [Ca]. The consistency in the timing of changes in Daphnia and inferred chlorophyll a suggests top-down control on algal production, providing, to our knowledge, the first evidence of a link between lakewater [Ca] decline and elevated algal production mediated through the effects of [Ca] decline on Daphnia. [Ca] decline has severe implications for whole-lake food webs, and presents yet another mechanism for potential increases in algal blooms.

Korosi, Jennifer B.; Burke, Samantha M.; Thienpont, Joshua R.; Smol, John P.

2012-01-01

364

78 FR 78783 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...  

Federal Register 2010, 2011, 2012, 2013

...fundyense, which can form blooms commonly referred to as red tides. Red tide blooms, also known as harmful algal blooms (HABs...state, and private laboratories. NOAA maintains a Red Tide Information Center...

2013-12-27

365

75 FR 76315 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...  

Federal Register 2010, 2011, 2012, 2013

...fundyense, which can form blooms commonly referred to as red tides. Red tide blooms, also known as harmful algal blooms (HABs...State, and private laboratories. NOAA maintains a Red Tide Information Center...

2010-12-08

366

76 FR 72125 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...  

Federal Register 2010, 2011, 2012, 2013

...which can form blooms commonly referred to as red tides. Red tide blooms, also known as harmful algal blooms (HABs...state, and private laboratories. NOAA maintains a Red Tide Information Center...

2011-11-22

367

77 FR 72994 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...  

Federal Register 2010, 2011, 2012, 2013

...fundyense, which can form blooms commonly referred to as red tides. Red tide blooms, also known as harmful algal blooms (HABs...state, and private laboratories. NOAA maintains a Red Tide Information Center...

2012-12-07

368

Satellites Harming Other Satellites.  

National Technical Information Service (NTIS)

A strategy is developed for assessing the harm that one satellite can do to another. A total of 29 modes are identified through which this harm can transpire, and the parameters and characteristics of each are explained. An overall, quantitative index of ...

P. C. Hughes

1991-01-01

369

Defining harm reduction.  

PubMed

Harm reduction attempts to reduce the adverse consequences of drug use among persons who continue to use drugs. It developed in response to the excesses of a "zero tolerance approach". Harm reduction emphasizes practical rather than idealized goals. It has been expanded from illicit drugs to legal drugs and is grounded in the evolving public health and advocacy movements. Harm reduction has proved to be effective and it has gained increasing official acceptance; for example, it is now the basis of Canada's Drug Strategy. However, the concept is still poorly defined, as virtually any drug policy or programme, even abstinence-oriented programmes, attempt to reduce drug-related harm. The principle feature of harm reduction is the acceptance of the fact that some drug users cannot be expected to cease their drug use at the present time. Harm reduction is neutral about the long term goals of intervention while according a high priority to short-term realizable goals. Harm reduction should be neutral about legalization. The essence of the concept is to ameliorate adverse consequences of drug use while, at least in the short term, drug use continues. PMID:16203323

Single, E

1995-01-01

370

Why "do no harm"?  

PubMed

Edmund Pellegrino has argued that the dramatic changes in American health care call for critical reflection on the traditional norms governing the therapeutic relationship. This paper offers such reflection on the obligation to "do no harm." Drawing on work by Beauchamp and Childress and Pellegrino and Thomasma, I argue that the libertarian model of medical ethics offered by Engelhardt cannot adequately sustain an obligation to "do no harm." Because the obligation to "do no harm" is not based simply on a negative duty of nonmaleficence but also on a positive duty of beneficence, I argue that it is best understood to derive from the fiduciary nature of the healing relationship. PMID:9129401

Sharpe, V A

1997-01-01

371

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

372

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

373

Advancing Access to New Technology for Sustained High Resolution Observations of Plankton: From Bloom Dynamics to Climate Change  

NASA Astrophysics Data System (ADS)

The combination of ocean observatory infrastructure and automated submersible flow cytometry can provide unprecedented capability for sustained high resolution time series of plankton, including taxa that are harmful or early indicators of ecosystem response to environmental change. Over the past decade, we have developed the FlowCytobot series of instruments that exemplify this capability. FlowCytobot and Imaging FlowCytobot use a combination of laser-based scattering and fluorescence measurements and video imaging of individual particles to enumerate and characterize cells ranging from picocyanobacteria to large chaining-forming diatoms. The process of developing these complex instruments was streamlined by access to the Martha's Vineyard Coastal Observatory (MVCO), a cabled facility on the New England Shelf, where real time two-way communications and access to shore power expedited cycles of instrument evaluation and design refinement. Repeated deployments at MVCO, typically 6 months in duration, have produced multi-year high resolution (hourly to daily) time series that are providing new insights into dynamics of community structure such as blooms, seasonality, and possibly even trends linked to regional climate change. The high temporal resolution observations of single cell properties make it possible not only to characterize taxonomic composition and size structure, but also to quantify taxon-specific growth rates. To meet the challenge of broadening access to this enabling technology, we have taken a two-step approach. First, we are partnering with a few scientific collaborators interested in using the instruments in different environments and to address different applications, notably the detection and characterization of harmful algal bloom events. Collaboration at this stage ensured that these first users outside the developers' lab had access to technical know-how required for successful outcomes; it also provided additional feedback that could be incorporated into more robust and user-friendly design. In the second and most recent stage, we have partnered with McLane Research Laboratories, Inc., a commercial vendor licensed to produce and market Imaging FlowCytobot. This stage of the development process has involved interactions between the scientific developers and company engineers, emphasizing joint construction of a pre-commercial prototype. A first run of commercially available units is anticipated to begin in the coming months paving the way for an expanding set of sustained high resolution plankton observations in conjunction with existing and emerging ocean observing systems.

Sosik, H. M.; Olson, R. J.

2012-12-01

374

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

375

Seasonal dynamics of harmful algae in outer Oslofjorden monitored by microarray, qPCR, and microscopy.  

PubMed

Monitoring of marine microalgae is important to predict and manage harmful algal blooms. Microarray Detection of Toxic ALgae (MIDTAL) is an FP7-funded EU project aiming to establish a multi-species microarray as a tool to aid monitoring agencies. We tested the suitability of different prototype versions of the MIDTAL microarray for the monthly monitoring of a sampling station in outer Oslofjorden during a 1-year period. Microarray data from two different versions of the MIDTAL chip were compared to results from cell counts (several species) and quantitative real-time PCR (qPCR; only Pseudochattonella spp.). While results from generation 2.5 microarrays exhibited a high number of false positive signals, generation 3.3 microarray data generally correlated with microscopy and qPCR data, with three important limitations: (1) Pseudo-nitzschia cells were not reliably detected, possibly because cells were not sufficiently retained during filtration or lysed during the extraction, and because of low sensitivity of the probes; (2) in the case of samples with high concentrations of non-target species, the sensitivity of the arrays was decreased; (3) one occurrence of Alexandrium pseudogonyaulax was not detected due to a 1-bp mismatch with the genus probe represented on the microarray. In spite of these shortcomings our data demonstrate the overall progress made and the potential of the MIDTAL array. The case of Pseudochattonella - where two morphologically similar species impossible to separate by light microscopy were distinguished - in particular, underlines the added value of molecular methods such as microarrays in routine phytoplankton monitoring. PMID:23325054

Dittami, Simon M; Hostyeva, Vladyslava; Egge, Elianne Sirnæs; Kegel, Jessica U; Eikrem, Wenche; Edvardsen, Bente

2013-10-01

376

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

377

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

378

Nitrogen fixation in Clear Lake, California.II. Synoptic studies on the autumn Anabaena bloom  

Microsoft Academic Search

Nitrogen fixation at three stages of an autumnal bloom of Anabaena circinulis was mea- sured after almost simultaneous collection at up to 32 stations in Clear Lake and algal hetcrocysts, phytoplankton cell numbers, NO,-N, NIL-N, dissolved organic-N, POh-P, Fe, primary production, particulate carbon, and chlorophyll a were also measured. Nitrogen fixation was significantly and positively correlated to Anabaena heterocyst numbers

ALEXANDER J. HORNE; J. E. DILLARD; D. K. FUJITA; C. R. GOLDMAN

1972-01-01

379

Factors controlling the onset of spring blooms in the German Bight 2002-2005: Light, wind and stratification  

NASA Astrophysics Data System (ADS)

Our quantitative understanding of the strong spatial and temporal variability in coastal algal spring blooms is yet much limited by the presence of changing physical forcing (e.g. tides, wind, precipitation and river runoff) on various spatio-temporal scales. In this study, we reconstructed the spring bloom dynamics of a shallow coastal marine ecosystem from 2002 to 2005 by combining three continuous time-series along a nearshore to offshore transect in the German Bight (GB). Nearshore, the timing and magnitude of the bloom remained nearly constant between years. At locations further offshore, bloom onset was related to water provenance, as expressed by salinity and the position of the tidal front. There, we could distinguish two regimes: (1) Under prevalence of turbid coastal waters, the bloom started early before stratification; Chl:C ratios increased with increasing mean water column irradiance, Im. (2) If the transitional water originated from the open North Sea, the bloom followed the stratification in late spring and depended less on Im; the Chl:C ratio was inversely related to Im and fluctuated widely. In both cases, we found a striking coincidence of wind-slack events ( ?5ms-1) and bloom onset. Particularly, a bi-weekly period with low wind below 5 m s -1 on average favoured the formation of a pronounced bloom. Our study demonstrates the critical role of mesoscale spatial variations (i.e. lateral mixing and stratification) for coastal plankton dynamics in winter-spring.

Tian, Tian; Su, Jian; Flöser, Götz; Wiltshire, Karen; Wirtz, Kai

2011-07-01

380

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

381

Phytoplankton Blooms - A Key Ecological Problem Of The Bulgarian Black Sea Coast  

Microsoft Academic Search

The Black Sea had a long history of chronic harmful phytoplankton blooms - phenomena, which was associated with strong negative impact on marine water quality and tourism. The impacts from these tiny organisms were many and diverse - illness of humans, fouling of beaches with foam, reduction of water transparency and decline in density of macroalgae, dead fish and shellfish.

Daniela Petrov; Violeta Velikova

2004-01-01

382

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

383

Using a multi-component indicator toward reducing phytoplankton bloom occurrences in the Swan River estuary.  

PubMed

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. PMID:22669343

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

2012-08-01

384

Satellite Detection of Phaeocystis Globosa Blooms in the Eastern English Channel  

NASA Astrophysics Data System (ADS)

Detecting phytoplankton species from remote sensing is essential to map and monitor algal blooms in coastal waters, but stays a challenge because of the interference of suspended sediments and dissolved organic matter with the phytoplankton signal. In the eastern English Channel and the south North Sea, a more or less intensive bloom of prymnesiophyceae Phaeocystis globosa occurs almost every spring and follows generally a first bloom of diatoms. From hyperspectral radiometric measurements (TRIOS; 350-950 nm, with a 3 nm resolution) concurrently performed with absorption, and backscattering measurements, as well as with phytoplankton species diversity determination, a spectral signature based on a derivative analysis was observed to discriminate the P. globosa blooms. In this study, we develop a multispectral approach to detect P. globosa blooms and investigate the possibility to apply this method to "ocean color" sensors (SeaWIFS). Then, we examine the impact of the bloom of P. globosa on the restitution of ocean color standard products, in particularly the chlorophyll a concentration (Chl), and examine new approaches to improve the restitution of Chl in this complex coastal environment.

Lubac, B.; Loisel, H.; Poteau, A.; Guiselin, N.

2006-12-01

385

Algal symbiosis: A mathematical analysis  

Microsoft Academic Search

Host and algal symbion growth can be described by an iterative model which incorporates utilization efficiencies of host and symbiont. This model predicts that, with input of organic matter to the host and at very low host and algal utilization efficiences coupled with efficient recycling of nutrients between the host and symbionts, production of organic matter by the system can

P. Hallock

1981-01-01

386

Is prostitution harmful?  

PubMed

A common argument against prostitution states that selling sex is harmful because it involves selling something deeply personal and emotional. More and more of us, however, believe that sexual encounters need not be deeply personal and emotional in order to be acceptable-we believe in the acceptability of casual sex. In this paper I argue that if casual sex is acceptable, then we have few or no reasons to reject prostitution. I do so by first examining nine influential arguments to the contrary. These arguments purport to pin down the alleged additional harm brought about by prostitution (compared to just casual sex) by appealing to various aspects of its practice, such as its psychology, physiology, economics and social meaning. For each argument I explain why it is unconvincing. I then weight the costs against the benefits of prostitution, and argue that, in sum, prostitution is no more harmful than a long line of occupations that we commonly accept without hesitation. PMID:22930676

Moen, Ole Martin

2014-02-01

387

Large-scale transport of Cochlodinium polykrikoides blooms by the Tsushima Warm Current in the southwest Sea of Japan  

Microsoft Academic Search

Since 2002, blooms of the harmful dinoflagellate Cochlodinium polykrikoides Margalef have occurred in the eastern San-in area, the Japanese coastal area fronting the southwest Sea of Japan. To investigate the occurrence mechanisms of the blooms, numerical experiments were conducted using a Lagrangian particle-tracking model, under different hydrographic conditions in 2002–2008. The results of Lagrangian simulations revealed that the source region

Goh Onitsuka; Kazutaka Miyahara; Naoki Hirose; Shuyo Watanabe; Hitoshi Semura; Reiko Hori; Tetsuya Nishikawa; Kuniaki Miyaji; Mineo Yamaguchi

2010-01-01

388

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

389

Floating Ice-Algal Aggregates below Melting Arctic Sea Ice  

PubMed Central

During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year.

Assmy, Philipp; Ehn, Jens K.; Fernandez-Mendez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A.; Hudson, Stephen R.; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H. H.; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

2013-01-01

390

Roseobacticides: Small Molecule Modulators of an Algal-Bacterial Symbiosis  

PubMed Central

Marine bacteria and microalgae engage in dynamic symbioses mediated by small molecules. A recent study of Phaeobacter gallaeciensis, a member of the large roseobacter clade of ?-proteobacteria, and Emiliania huxleyi, a prominent member of the microphytoplankton found in large algal blooms, revealed that an algal senescence signal produced by E. huxleyi elicits the production of novel algaecides, the roseobacticides, from the bacterial symbiont. In this report, the generality of these findings are examined by expanding the number of potential elicitors. This expansion led to the identification of nine new members of the roseobacticide family, rare bacterial troponoids, which provide insights into both their biological roles and their biosynthesis. The qualitative and quantitative changes in the levels of roseobacticides induced by the additional elicitors and the elicitors’ varied efficiencies support the concept of host-targeted roseobacticide production. Structures of the new family members arise from variable substituents at the C3 and C7 positions of the roseobacticide core as the diversifying elements and suggest that the roseobacticides result from modifications and combinations of aromatic amino acids. Together these studies support a model in which algal senescence converts a mutualistic bacterial symbiont into an opportunistic parasite of its hosts.

2011-01-01

391

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

392

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.

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

2011-01-01

393

Mentor Profiles -Kevin Harm  

NSDL National Science Digital Library

Considering his job, Kevin's last name doesn't make sense. Kevin got into nursing because he wants to help, not harm, people. Kevin didn't know what he wanted to do right away; he had another career before nursing. Read about him here.

Gem-Nursing

394

Variability of factors driving spatial and temporal dispersion in river plume and Chattonella antiqua bloom in the Yatsushiro Sea, Japan.  

PubMed

The dynamics of river plume in relation to harmful blooms of the raphidophycean flagellate, Chattonella antiqua in summer 2008-2010 in the Yatsushiro Sea, Japan were studied using a hydrodynamic model and monitoring data. In the southern area, the bloom formed in the waters stratified by a halocline caused by the southward expansion of riverine water from the Kuma River after the bloom initially forming in the northern area. The timing of the southward riverine water advection can be explained by the balance between the wind stress term and the pressure gradient term calculated from the horizontal density difference between the northern and southern areas. The wind stress and pressure gradient terms were evaluated using the sea surface temperature, salinity, wind speed and direction at two stations. Real time monitoring or continuous observations in these areas will enable nowcasts of bloom expansion when a bloom develops in the northern area. PMID:24576389

Aoki, Kazuhiro; Onitsuka, Goh; Shimizu, Manabu; Kuroda, Hiroshi; Matsuo, Hitoshi; Kitadai, Yuuki; Sakurada, Kiyonari; Ando, Hidenori; Nishi, Hiromi; Tahara, Yoshio

2014-04-15

395

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

396

Allergy Season Springs into Bloom  

MedlinePLUS

... sharing features on this page, please enable JavaScript. Allergy Season Springs Into Bloom Allergist outlines ways to ... this long, cold winter, but those with pollen allergies might not greet spring with open arms. There ...

397

Allelopathic inhibition of competing phytoplankton by North American strains of the toxic dinoflagellate, Alexandrium fundyense: Evidence from field experiments, laboratory experiments, and bloom events  

Microsoft Academic Search

The role of allelopathy in bloom formation by the paralytic shellfish poisoning (PSP) dinoflagellate, Alexandrium fundyense, was examined using five strains isolated from across the latitudinal PSP-toxicity gradient found along the North American East Coast. We specifically present bi-algal laboratory experiments, field experiments using cultured A. fundyense and natural phytoplankton communities, and the temporal dynamics of plankton assemblages during A.

Theresa K. Hattenrath-Lehmann; Christopher J. Gobler

2011-01-01

398

Harmful Algae Digital Library  

NSDL National Science Digital Library

The Harmful Algae Digital Library contains a collection of Sea Grant documents in digital format (primarily PDF) arranged by subject area: red tide/PSP, brown tide, ciguatera, killer algae, and Pfiesteria. This collection is part of the National Sea Grant Library (NSGL), which maintains over 36,000 searchable records dedicated to environmental stewardship, long-term economic development and responsible use of America's coastal, ocean and Great Lakes resources.

Library, National S.; University Of Rhode Island-Bay Campus, Noaa

399

Effects of climatic variability on phytoplankton community structure and bloom development in the eutrophic, microtidal, New River Estuary, North Carolina, USA  

NASA Astrophysics Data System (ADS)

The roles of climatically driven freshwater flow, nutrient loading, and temperature on phytoplankton community biomass and composition were examined along a downstream transect within the New River Estuary, North Carolina from 2007 to 2010. This microtidal system has a history of eutrophication symptoms, including harmful algal blooms. Riverine discharge strongly controlled nutrient loading to the estuary. Except during very high flow conditions, loads were generally assimilated near the head of the estuary and low concentrations of dissolved inorganic nitrogen and phosphate, <2 and 0.4 ?mol L-1, respectively, were found throughout most of the estuary. Total phytoplankton biomass (chlorophyll a) was maximal under moderate discharge conditions when flushing time was approximately four days and salinity was in the range of 3-18 psu. The observed non-monotonic relationship between phytoplankton biomass and flushing time reflects a balance between nutrient stimulation of phytoplankton biomass and advective losses associated with river flow. Pigment indicators of major phytoplankton taxa also revealed non-monotonic responses to flushing time with some significant inter-taxa differences in slopes and peak location. These differences suggest that flushing time or environmental covariates of flushing time are important determinants of community composition. We suggest these group-specific differences are due to advantages gained by phytoflagellates through vertical migration, ability of pico-cyanobacteria to exploit low residual nutrient concentrations, and subsidies to the diatom population via sediment resuspension events. In addition to effects of flow, pico-cyanobacteria and harmful raphidophyte taxa demonstrated positive relationships with temperature. Overall, results demonstrate a strong linkage between the phytoplankton community and two important climatic drivers, flow and temperature. The observed sensitivity of phytoplankton biomass to nutrient loads suggests that load reductions (or increases) are likely to decrease (or increase) total phytoplankton biomass in this system. However, phytoplankton community composition appears to be largely determined by environmental factors other than nutrient loading, particularly temperature, stratification and sediment resuspension.

Hall, Nathan S.; Paerl, Hans W.; Peierls, Benjamin L.; Whipple, Anthony C.; Rossignol, Karen L.

2013-01-01

400

The growth dynamics of Karenia brevis within discrete blooms on the West Florida Shelf  

NASA Astrophysics Data System (ADS)

As part of the ECOHAB: Florida Program, we studied three large blooms of the harmful bloom forming dinoflagellate Karenia brevis. These blooms formed on the West Florida Shelf during Fall of 2000 off Panama City, and during Fall 2001 and Fall 2002 off the coastline between Tampa Bay and Charlotte Harbor. We suggest that these blooms represent two different stages of development, with the 2000 and 2001 blooms in an active growth or maintenance phase and the 2002 bloom in the early bloom initiation phase. Each bloom was highly productive with vertically integrated primary production values of 0.47-0.61, 0.39-1.33 and 0.65 g C m -2 d -1 for the 2000, 2001 and 2002 K. brevis blooms, respectively. Carbon specific growth rates were low during each of these blooms with values remaining fairly uniform with depth corresponding to generation times of 3-5 days. Nitrogen assimilation by K. brevis was highest during 2001 with values ranging from 0.15 to 2.14 ?mol N L -1 d -1 and lower generally for 2000 and 2002 (0.01-0.64 and 0.66-0.76 ?mol N L -1 d -1 for 2000 and 2002, respectively). The highest K. brevis cell densities occurred during the 2001 bloom and ranged from 400 to 800 cells mL -1. Cell densities were lower for each of the 2000 and 2002 blooms relative to those for 2001 with densities ranging from 100 to 500 cells mL -1. The 2000 and 2001 blooms were dominated by K. brevis in terms of its contribution to the total chlorophyll a (chl a) pool with K. brevis accounting generally for >70% of the observed chl a. For those populations that were dominated by K. brevis (e.g. 2000 and 2001), phytoplankton C biomass (C p,0) constituted <30% of the total particulate organic carbon (POC). However, in 2002 when diatoms and K. brevis each contributed about the same to the total chl a, C p,0 was >72% of the POC. The fraction of the total chl a that could be attributed to K. brevis was most highly correlated with POC, chl a and salinity. Nitrogen assimilation rate and primary production were highly correlated with a greater correlation coefficient than all other comparisons.

Redalje, D. G.; Lohrenz, S. E.; Natter, M. J.; Tuel, M. D.; Kirkpatrick, G. J.; Millie, D. F.; Fahnenstiel, G. L.; Van Dolah, F. M.

2008-01-01

401

[Effects of thermal stratification on spring blooms in Xiangxi Bay of the Three Gorges Reservoir].  

PubMed

Frequent spring blooms have been observed in tributary bays of the Three Gorges Reservoir (TGR) since its initial filling. In order to identify the primary factor controlling spring blooms, a field monitoring plan was carried out in Xiangxi Bay, the largest tributary of TGR head area in spring 2010. The environmental factors such as water temperature, Secchi depth, underwater illumination and nutrients were monitored. The results showed that the sudden decrease of mixing depth resulting from the development of thermal stratification was the direct and primary contributor to the onset of spring