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.
This online textbook contains detailed information about harmful algal blooms (HABs). Topics include HAB related health hazards, general information about HABs, and taxonomic information regarding different harmful algae. The site also features links to specific aforementioned topic-related sites and maps of observed blooms in Europe and North America, Florida datasets, and historical/real-time data produced by NOAA. It also contains color photographs related to HABs.
Stewart, Robert R.; Department of Oceanography, Texas A&M University
Teaching unit investigates differences between toxic and non-toxic harmful algal blooms (HABs), where they occur in U.S. waters, causative phytoplankton species, technologies for detecting blooms, which organisms in the food web are affected and how, effects of specific toxins on humans. Five lessons contain: background and glossary; instructions for classroom and lab activities; online data; web links for further study. Lessons are aligned to teaching standards.
This comprehensive NOAA pdf file contains in depth information about harmful algal blooms (HABs) in the United States. The article contains general information about HABs, location-based assessments of HABs, and case studies of the problem. The article features color photographs of affected areas.
Administration, National O.
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
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.
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.
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...
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
Algal blooms have recently attracted significant attention due to their human and ecological effects. The aim of this technical note is to assess the importance of freshwater harmful algal blooms (HABs) to U.S. Army Corps of Engineers (USACE) operations t...
D. Loney F. K. Satterstrom I. Linkov J. A. Steevens
With an apparent increase of harmful algal blooms (HABs) worldwide, healthcare providers, public health personnel and coastal managers are struggling to provide scientifically-based appropriately-targeted HAB outreach and education. Since 1998, the Florida Poison Information Center-Miami, with its 24 hour/365 day/year free Aquatic Toxins Hotline (1–888–232–8635) available in several languages, has received over 25,000 HAB-related calls. As part of HAB surveillance, all possible cases of HAB-related illness among callers are reported to the Florida Health Department. This pilot study evaluated an automated call processing menu system that allows callers to access bilingual HAB information, and to speak directly with a trained Poison Information Specialist. The majority (68%) of callers reported satisfaction with the information, and many provided specific suggestions for improvement. This pilot study, the first known evaluation of use and satisfaction with HAB educational outreach materials, demonstrated that the automated system provided useful HAB-related information for the majority of callers, and decreased the routine informational call workload for the Poison Information Specialists, allowing them to focus on callers needing immediate assistance and their healthcare providers. These results will lead to improvement of this valuable HAB outreach, education and surveillance tool. Formal evaluation is recommended for future HAB outreach and educational materials.
Fleming, Lora E.; Jerez, Eva; Stephan, Wendy Blair; Cassedy, Amy; Bean, Judy A; Reich, Andrew; Kirkpatrick, Barbara; Backer, Lorraine; Nierenberg, Kate; Watkins, Sharon; Hollenbeck, Julie; Weisman, Richard
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
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
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.
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
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
Recent development of hyperspectral remote sensing provides capability to identify and classify harmful algal blooms beyond the estimation of chlorophyll concentrations. This study uses hyperspectral data to extract spectral signatures, classify algal blooms, and map the spatial distribution of the algal blooms in the upper Chesapeake Bay. Furthermore, water quality parameters from ground stations have been used together with remote
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
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
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
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 ...
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. PMID:22046341
Park, Seong-Cheol; Lee, Jong-Kook; Kim, Si Wouk; Park, Yoonkyung
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
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.
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
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...
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
The inhibition effect of sophorolipid and removal efficiency of loess on Cochlodinium polykrikoides and Alexandrium tamarense was investigated separately in the laboratory. Based on this, the combination of sophorolipid and loess for harmful algal bloom mitigation was proposed. Algal sedimentation tests in the laboratory and in the field revealed that the combination of sophorolipid and loess showed synergistic effects both
Xiao-Xia Sun; Young-Ju Lee; Joong-Ki Choi; Eun-Ki Kim
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.
Clay dispersal is one of the most promising strategies for controlling harmful algal blooms. It is based on the mutual aggregation of algal cells with mineral particles, leading to aggregate settling. This research demonstrated the effectiveness of domest...
M. R. Sengco
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...
Economic progress has been rapid around the Daya Bay region of the northern South China Sea (SCS) over recent decades. To investigate changes of Harmful Algal Blooms (HABs) caused by environmental situation in the bay area, the present study analyzed the occurrence of HAB and environ- mental conditions in Daya Bay using in situ and satellite remote sensing data for
Jing Yu; Dan-Ling Tang; Im-Sang Oh; Li-Jun Yao
An in vivo 3D fluorescence discrimination technique for ten harmful algal bloom (HAB) species that belong to eight genera of four divisions was developed by wavelet analysis. Daubechies-7 (db7) was employed as the mother wavelet. The fifth scale domains were selected as the discriminant characteristic spectra (DCS). Based on the DCS, The phytoplankton species at different growth stages were classified
Fang Zhang; Rongguo Su; Xiulin Wang; Liang Wang; Jianfeng He; Minghong Cai; Wei Luo; Zhixia Zheng
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
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
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)
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
This study examined a new method of mitigating harmful algal blooms (HABs) by combining biosurfactant sophorolipid and yellow clay. To investigate the effects and practicability of this HAB mitigation method, field experiments were carried out during a Cochlodinium bloom near Miruk Island, South Korea, in August 2002. Field experiments examined the effects of sophorolipid and yellow clay on Cochlodinium bloom
Young-Ju Lee; Joong-Ki Choi; Eun-Ki Kim; Seok-Hyun Youn; Eun-Jin Yang
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
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
In 2002, the Florida Department of Environmental Protection began discharging phosphate-processing effluent into Bishop Harbor, an estuary within Tampa Bay. Because of concerns that the effluent would serve as a nutrient source for blooms of the toxic dinoflagellate Karenia brevis, a field monitoring program was established and laboratory bioassays were conducted. Several harmful algal bloom (HAB) species, including Prorocentrum minimum and Heterosigma akashiwo, were observed in bloom concentrations adjacent to the effluent discharge site. Blooms of diatoms were widespread throughout Bishop Harbor. K. brevis was observed with cell concentrations decreasing with increasing proximity to the effluent discharge site. Bioassays using effluent as a nutrient source for K. brevis resulted in decreased cell yields, increased growth rates, and increased time to log-phase growth. The responses of HAB species within Bishop Harbor and of K. brevis to effluent in bioassays suggested that HAB species differ in their response to phosphate-processing effluent. PMID:21145070
Garrett, Matthew; Wolny, Jennifer; Truby, Earnest; Heil, Cynthia; Kovach, Charles
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
John J. Walsh; Dwight A. Dieterle; F. Robert Chen; Jason M. Lenes; Wieslaw Maslowski; John J. Cassano; Terry E. Whitledge; Dean Stockwell; Mikhail Flint; Irina N. Sukhanova; John Christensen
Increased interest in using ecologically inert clays to flocculate, sediment, and thus mitigate harmful algal blooms at nearshore mariculture sites has prompted studies on the effectiveness of this method on prolific blooms, such as those caused by the neurotoxic dinoflagellate Karenia brevis in the Gulf of Mexico. Potential repercussions of this control strategy revolve around the increased flux of suspended
Marie-Claude Archambault; V. Monica Bricelj; Jon Grant; Donald M. Anderson
Due to slow rates of molecular evolution, DNA sequences used to identify and build phylogenies of algal species involved in harmful algal blooms (HABs) are generally invariant at the intraspecific level. This means that it is unknown whether HAB events result from the growth of a single clone, a few dominant clones, or multiple clones. This is true despite the fact that several physiological and demographic traits, as well as toxicity, are known to vary across clones. We generated AFLP fingerprints from a set of 6 clonal isolates, taken from a bloom of Prymnesium parvum at a striped bass mariculture facility. This new haptophyte bloom was recently implicated in fish kills at several sites in the United States. The AFLP fragments were highly reproducible and showed that all isolates were distinguishable due to abundant AFLPs unique to single isolates. These results demonstrate that blooms can be genetically diverse outbreaks and indicate that AFLP can be a powerful molecular tool for characterizing and monitoring this diversity. PMID:21885572
Barreto, Felipe S; Tomas, Carmelo R; McCartney, Michael A
The research on the effects of harmful algal bloom (HAB) algae on zooplankton has been drawn more and more attention. This paper summarized the adverse effects of HAB algae on zooplankton, which included reduced survival, inhibited growth, reduced fecundity of female, fertilization failure of eggs or hatching failure of zygote, inhibited embryo development, naupliar abnormal development or abnormality, inhibited grazing and changed behavior of zooplankton, etc. The main intoxication ways included decreased utilization of food, physiology impairment, damaged cell membrane, reduced gamete quality, and inhibited mitotic and embryo development by phycotoxins or exudations released by algae. Additionally, the lack of full nutrition, especially of polyunsaturated fatty acids in some algal species cells could also affect zooplankton growth and reproduction. PMID:14587351
Wang, Liping; Yan, Tian; Tan, Zhijun; Zhou, Mingjiang
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
Harmful algal blooms are believed to be increasing in occurrence and their toxins can be concentrated by filter-feeding shellfish and cause amnesia or paralysis when ingested. As a result fisheries and beaches in the vicinity of blooms may need to be closed and the local population informed. For this avoidance planning timely information on the existence of a bloom, its species and an accurate map of its extent would be prudent. Current research to detect these blooms from space has mainly concentrated on spectral approaches towards determining species. We present a novel statistics-based background-subtraction technique that produces improved descriptions of an anomaly's extent from remotely-sensed ocean colour data. This is achieved by extracting bulk information from a background model; this is complemented by a computer vision ramp filtering technique to specifically detect the perimeter of the anomaly. The complete extraction technique uses temporal-variance estimates which control the subtraction of the scene of interest from the time-weighted background estimate, producing confidence maps of anomaly extent. Through the variance estimates the method learns the associated noise present in the data sequence, providing robustness, and allowing generic application. Further, the use of the median for the background model reduces the effects of anomalies that appear within the time sequence used to generate it, allowing seasonal variations in the background levels to be closely followed. To illustrate the detection algorithm's application, it has been applied to two spectrally different oceanic regions.
Shutler, J. D.; Grant, M. G.; Miller, P. I.
Harmful algal blooms in the Chesapeake Bay and coastal bays of Maryland, USA, are not a new phenomenon, but may be increasing\\u000a in frequency and diversity. Outbreaks ofPfiesteria piscicida (Dinophyceae) were observed during 1997 in several Chesapeake Bay tributaries, while in 1998,Pfiesteria-related events were not found but massive blooms ofProrocentrum minimum (Dinophyceae) occurred. In 1999,Aureococcus anophagefferens (Pelagophyceae) developed in the
Patricia M. Glibert; Robert Magnien; Michael W. Lomas; Jeffrey Alexander; Chunlei Tan; Erin Haramoto; Mark Trice; Todd M. Kana
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
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 using satellite remote sensing data. The HAB had high chlorophyll a (Chl a) concentrations (up to 4.5 mg m-3) occurring ˜200 km off the coast and ˜200 km northeast of the Mekong River mouth for a period of ˜6 weeks. The bloom was dominated by the harmful algae haptophyte Phaeocystis cf. globosa and caused a very significant mortality of aquacultured fish and other marine life. In the same period, sea surface temperature (SST) imagery showed a cold water plume extending from the coast to the open sea, and QuikScat data showed strong southwesterly winds blowing parallel to the coastline. This study indicated that the HAB was induced and supported by offshore upwelling that brings nutrients from the deep ocean to the surface and from coastal water to offshore water and that the upwelling was driven by strong wind through Ekman transport when winds were parallel to the coastline. This study demonstrated the possibility of utilizing a combination of satellite data of Chl a, SST, and wind velocity together with coastal bathymetric information and in situ observations to give a better understanding of the biological oceanography of HABs.
Tang, Dan Ling; Kawamura, Hiroshi; Doan-Nhu, Hai; Takahashi, Wataru
The public health, tourism, fisheries, and ecosystem impacts from harmful algal blooms (HABs) have all increased over the past few decades. This has led to heightened scientific and regulatory attention, and the development of many new technologies and approaches for research and management. This, in turn, is leading to significant paradigm shifts with regard to, e.g., our interpretation of the phytoplankton species concept (strain variation), the dogma of their apparent cosmopolitanism, the role of bacteria and zooplankton grazing in HABs, and our approaches to investigating the ecological and genetic basis for the production of toxins and allelochemicals. Increasingly, eutrophication and climate change are viewed and managed as multifactorial environmental stressors that will further challenge managers of coastal resources and those responsible for protecting human health. Here we review HAB science with an eye toward new concepts and approaches, emphasizing, where possible, the unexpected yet promising new directions that research has taken in this diverse field.
Anderson, Donald M.; Cembella, Allan D.; Hallegraeff, Gustaaf M.
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.
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
A universal environmental friendly method was developed to turn sand into effective flocculants for mitigating harmful algal blooms (HABs) in marine and freshwater systems. The isoelectric point of sand was largely increased from pH 4.5 to 10.5 after been modified by Moringa oleifera coagulant (MO) abstracted form MO seeds. However, when sand was modified by MO alone, maximum removal efficiencies of 80% and 20% for Amphidinium carterae (A.C.) and Chlorella sp. (C.S.) in seawater and 60% for Microcystis aeruginosa (M.A.) in fresh water were achieved in 30 min. The limited removal improvement was due to the form of only small flocs (20-100 ?m) by surface charge modification only. Large flocs (270-800 ?m) and high removal rate of 96% A.C. and C.S. cells in seawater and 90% of M.A. cells in fresh water were achieved within 30 min when the small MO-algae-sand flocs were linked and bridged by chitosan. High HAB removal rate is achievable when the sand is modified by the bicomponent mechanism of surface charge and netting-bridging modification using biodegradable modifiers such as MO and chitosan. The optimized dosage of modified sand depends on the property of algal cells and water conditions. PMID:23611410
Li, Liang; Pan, Gang
In the plankton, heterotrophic microbes encounter and ingest phytoplankton prey, which effectively removes >50% of daily phytoplankton production in the ocean and influences global primary production and biochemical cycling rates. Factors such as size, shape, nutritional value, and presence of chemical deterrents are known to affect predation pressure. Effects of movement behaviors of either predator or prey on predation pressure, and particularly fleeing behaviors in phytoplankton are thus far unknown. Here, we quantified individual 3D movements, population distributions, and survival rates of the toxic phytoplankton species, Heterosigma akashiwo in response to a ciliate predator and predator-derived cues. We observed predator-induced defense behaviors previously unknown for phytoplankton. Modulation of individual phytoplankton movements during and after predator exposure resulted in an effective separation of predator and prey species. The strongest avoidance behaviors were observed when H. akashiwo co-occurred with an actively grazing predator. Predator-induced changes in phytoplankton movements resulted in a reduction in encounter rate and a 3-fold increase in net algal population growth rate. A spatially explicit population model predicted rapid phytoplankton bloom formation only when fleeing behaviors were incorporated. These model predictions reflected field observations of rapid H. akashiwo harmful algal bloom (HAB) formation in the coastal ocean. Our results document a novel behavior in phytoplankton that can significantly reduce predation pressure and suggests a new mechanism for HAB formation. Phytoplankton behaviors that minimize predatory losses, maximize resource acquisition, and alter community composition and distribution patterns could have major implications for our understanding and predictive capacity of marine primary production and biochemical cycling rates. PMID:23029518
Harvey, Elizabeth L; Menden-Deuer, Susanne
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
Over the past two decades, Harmful Algal Blooms (HABs) appear to have increased in frequency, intensity and geographic distribution worldwide, and have caused large economic losses in aquacultured and wild fisheries in recent years. Understanding of the oceanic mechanisms is important for early warning of HAB events. The present study reported several extensive HABs in the Asian waters during 1998 to 2003 detected by satellite remote sensing data (SeaWiFS, NOAA AVHRR, and QuikScat) and in situ observations. An extensive HAB off southeastern Vietnamese waters during late June to July 2002 was detected and its related oceanographic features were analyzed. The HAB had high Chlorophyll-a (Chl-a) concentrations (up to 4.5 mg m-3), occurring about 200 km off the coast and about 200 km northeast of the Mekong River mouth, for a period of about 6 weeks. The bloom was dominated by the harmful algae haptophyte Phaeocystis cf. globosa, and caused a very significant mortality of aquacultured fishes and other marine life. In the same period, Sea Surface Temperature (SST) imagery showed a coldwater plume extending from the coast to the open sea, and QuikScat data showed strong southwesterly winds blowing parallel with the coastline. It indicated the HAB was induced and supported by offshore upwelling that bring nutrients from the deep ocean to the surface and from coastal water to the offshore, and the upwelling was driven by strong wind through Ekman transport when winds were parallel with the coastline. This study demonstrated the possibility of utilizing a combination of satellite data of Chl-a, SST and wind velocity together with coastal bathymetric information and in situ observation to give a better understanding of the biological oceanography of HABs; these results may help for the early warming of HAB.
Tang, D. L.
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
The immediate early gene c-fos, and its protein product c-Fos, are known to be induced in neurons of mammals and fish as a result of neuronal stimulation. The purpose of this study was to quantitatively examine CNS alterations in killifish, Fundulus heteroclitus, in relation to harmful algal bloom (HAB) toxin exposure. c-Fos expression was visualized using immunocytochemistry in the brains
J. D. Salierno; N. S. Snyder; A. Z. Murphy; M. Poli; S. Hall; D. Baden; A. S. Kane
The incidence and severity of harmful algal blooms have increased in recent decades, as have the economic effects of their occurrence. The diatom Pseudo-nitzschia spp. caused fisheries closures in Mobile Bay during 2005 due to elevated levels of domoic acid. In the previous 4 years Karenia brevis counts of >5,000 cells L-1 have occurred in Mobile Bay and the Mississippi Sound. Population levels of this magnitude had previously been recorded only in 1996. Increases in human populations, urban sprawl, development of shoreline properties, sewage effluent and resultant changes in N-P ratios of discharge waters, and decline in forest and marsh lands, will potentially increase future harmful algal bloom occurrences in the northern Gulf of Mexico. Due to this trend in occurrence of harmful algal populations, there has been an increasing awareness of the need for development of monitoring systems in this region. Traditional methods of sampling have proven costly in terms of time and resources, and increasing attention has been turned toward use of satellite data in phytoplankton monitoring and prediction. This study shows that remote sensing does have utility in monitoring and predicting locations of phytoplankton blooms in this region. It has described the composition and spatial and temporal relationships of these populations, inferring salinity, total nitrogen and total phosphorous as the primary variables driving phytoplankton populations in Mobile Bay and the Mississippi Sound. Diatoms, chlorophytes, cryptophytes, and dinoflagellates were most abundant in collections. Correlations between SeaWiFS, MODIS and in situ data have shown relationships between Rrs reflectance and phytoplankton populations. These data were used in formation of a decision tree model predicting environmental conditions conducive to the formation of phytoplankton blooms that is driven completely by satellite data. Empirical algorithms were developed for prediction of salinity, based on Rrs ratios of 510 nm/555 nm, creating a new data product for use in harmful algal bloom prediction. The capacity of satellite data for rapid, synoptic coverage shows great promise in supplementing future efforts to monitor and predict harmful algal bloom events in the increasingly eutrophic waters of Mobile Bay and the Mississippi Sound.
Holiday, Dan Martin
As part of efforts to enhance the strategies employed to manage and mitigate algal blooms and their adverse effects, algicidal bacteria have shown promise as potential suppressors of these events. Nine strains of bacteria algicidal against the toxic dinoflagellate, Alexandrium tamarense, were isolated from the East Sea area, China. Sequence analysis of 16S rDNA showed that all the algicidal bacteria
Jianqiang Su; Xiaoru Yang; Yanyan Zhou; Tianling Zheng
Microorganisms have attracted worldwide attention as possible agents for inhibiting water blooms. Algae are usually indirectly inhibited and degraded by secretion from microorganisms. In this study, algal cultures Microcystis aeruginosa (Ma) FACH-918, Microcystis flos-aquae (Mf) FACH-1028, Oocystis borgei (Ob) FACH-1108, and M. aeruginosa PCC 7806 were co-cultured with the fungus strain Trichaptum abietinum 1302BG. All algal cells were destroyed within 48 hours (h) of co-incubation. Scanning electron microscope and transmission electron microscope observation revealed that the fungal strain had preying ability on the algal cells. The mechanism may be that the algal cells were encased with a mucous membrane secreted by the fungal mycelia, and finally degraded by the fungus directly. PMID:20675050
Jia, Yong; Han, Guomin; Wang, Congyan; Guo, Peng; Jiang, Wenxin; Li, Xiaona; Tian, Xingjun
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
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
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
The recent identification of genes involved in the production of the potent neurotoxin and keystone metabolite saxitoxin (STX) in marine eukaryotic phytoplankton has allowed us for the first time to develop molecular genetic methods to investigate the chemical ecology of harmful algal blooms in situ. We present a novel method for detecting and quantifying the potential for STX production in marine environmental samples. Our assay detects a domain of the gene sxtA that encodes a unique enzyme putatively involved in the sxt pathway in marine dinoflagellates, sxtA4. A product of the correct size was recovered from nine strains of four species of STX-producing Alexandrium and Gymnodinium catenatum and was not detected in the non-STX-producing Alexandrium species, other dinoflagellate cultures, or an environmental sample that did not contain known STX-producing species. However, sxtA4 was also detected in the non-STX-producing strain of Alexandrium tamarense, Tasmanian ribotype. We investigated the copy number of sxtA4 in three strains of Alexandrium catenella and found it to be relatively constant among strains. Using our novel method, we detected and quantified sxtA4 in three environmental blooms of Alexandrium catenella that led to STX uptake in oysters. We conclude that this method shows promise as an accurate, fast, and cost-effective means of quantifying the potential for STX production in marine samples and will be useful for biological oceanographic research and harmful algal bloom monitoring.
Murray, Shauna A.; Wiese, Maria; Stuken, Anke; Brett, Steve; Kellmann, Ralf; Hallegraeff, Gustaaf; Neilan, Brett A.
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
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
Antonella, Penna; Luca, Galluzzi
Evidence for shellfish toxin illness in British Columbia (BC) on the west coast of Canada can be traced back to 1793. For over two hundred years, domestically acquired bivalve shellfish toxin illnesses in BC were solely ascribed to paralytic shellfish poisonings caused by algal blooms of Alexandrium. This changed in 2011, when BC experienced its first outbreak of diarrhetic shellfish poisoning (DSP). As a result of this outbreak, Canada's first DSP symposium was held in November, 2012, in North Vancouver, BC. Three of the objectives of the symposium were to provide a forum to educate key stakeholders on this emerging issue, to identify research and surveillance priorities and to create a DSP network. The purpose of this paper is to review what is known about shellfish poisoning in BC and to describe a novel volunteer network that arose following the symposium. The newly formed network was designed for industry shellfish growers to identify harmful algae bloom events, so that they may take actions to mitigate the effects of harmful blooms on shellfish morbidity. The network will also inform public health and regulatory stakeholders of potentially emerging issues in shellfish growing areas. PMID:24172211
McIntyre, Lorraine; Cassis, David; Haigh, Nicola
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.
Harmful Algal Blooms (HABs) are truly global marine phenomena of increasing significance. Many HAB occurrences may have been not recorded because of their high spatial and temporal variability and of their advection, once formed, by surface currents. A serious HAB occurred in the Bohai Sea in autumn 1998, dominated by the species Ceratium furca sp, causing the largest fisheries economic loss recorded in that region. The present study traced the formation and advection of that HAB in September 1998 in the northern Bohai Sea by satellite SeaWiFS ocean color data and correlated the spatial and temporal changes with oceanographic data. The results show that the bloom originated in the coastal water in the west of the Bohai Sea in early September when sea surface temperature increased to 25-26 °C. The bloom biomass was shifted southeastward and intensified around the center portion of the sea in the mid September. The bloom covered an area of 60 x 65 km^2 with high Chl-a concentration (6.5 mg m-3) in the bloom center. At the end of September, the bloom decayed in the eastern Bohai Sea when water temperature decreased to 22-23 °C. Northeasterly winds were recorded in August and September, and northwesterly winds in late September, October and November. The HAB may have been initiated by a combination of the nutrients from river discharges in the coastal waters of the west of the Bohai Sea and the increase of water temperature; it may have been then advected eastward by the northern Bohai Sea circulation enhanced by northwesterly winds in late September-early October.
Tang, D. L.; Kawamura, H.; Oh, I. S.; Baker, Joe
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
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
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
Harmful algal blooms (HABs) attributed to Pseudo-nitzschia species, a diatom that produces Domoic acid, are a common occurrence and serious threat along the coast of the US Northwest. Monitoring these events or providing advanced warning of their occurrence at the coast would provide an important aid to fisheries managers. Remote sensing, which is being used in the Gulf of Mexico for HAB detection and forecasting (of a different algae), could provide a tool for monitoring and warnings. Chlorophyll and SST imagery are being used to support a research and monitoring program for the region, and HAB monitoring techniques used in the Gulf of Mexico are being examined for their potential utility along the Washington coast. The focus of this study is to determine the efficacy of using satellite ocean color imagery for HAB monitoring off of Washingtons Olympic Peninsula region, and to provide support in the form of ocean color imagery products for management and mitigation efforts.
Holt, Ashley C.; Stumpf, Richard P.; Tomlinson, Michelle C.; Ransibrahmanakul, Varis; Trainer, Vera L.; Woodruff, Dana L.
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
Microcystin poisoning was diagnosed in a dog exposed to a Microcystis aeruginosa-dominated, freshwater, harmful algal bloom at Milford Lake, Kansas, which occurred during the summer of 2011. Lake water microcystin concentrations were determined at intervals during the summer, using competitive enzyme-linked immunosorbent assays, and indicated extremely high, localized microcystin concentrations of up to 126,000 ng/ml. Multiple extraction and analysis techniques were used in the determination of free and total microcystins in vomitus and liver samples from the poisoned dog. Vomitus and liver contained microcystins, as determined by enzyme-linked immunosorbent assays, and the presence of microcystin-LR was confirmed in vomitus and liver samples using liquid chromatography coupled with tandem mass spectrometry. Major toxic effects in a dog presented for treatment on the day following exposure included fulminant liver failure and coagulopathy. The patient deteriorated rapidly despite aggressive treatment and was euthanized. Postmortem lesions included diffuse, acute, massive hepatic necrosis and hemorrhage, as well as acute necrosis of the renal tubular epithelium. A diagnosis of microcystin poisoning was based on the demonstration of M. aeruginosa and microcystin-LR in the lake water, as well as in vomitus produced early in the course of the poisoning; the presence of microcystin-LR in liver tissue; and a typical clinical course including gastroenteritis and fulminant liver failure. PMID:22604771
van der Merwe, Deon; Sebbag, Lionel; Nietfeld, Jerome C; Aubel, Mark T; Foss, Amanda; Carney, Edward
“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
Melissa A. Miller; Raphael M. Kudela; Abdu Mekebri; Dave Crane; Stori C. Oates; M. Timothy Tinker; Michelle Staedler; Woutrina A. Miller; Sharon Toy-Choutka; Clare Dominik; Dane Hardin; Gregg Langlois; Michael Murray; Kim Ward; David A. Jessup
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
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.
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.
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
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.
Lovejoy, Connie; Bowman, John P.; Hallegraeff, Gustaaf M.
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
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
According to two cruises in the high frequency area of Harmful Algal Blooms (HABs) in ECS from Apr. 8th to 26th and May 7th to 14th 2010, concentrations and distributions of biogenic elements before and after HABs were analyzed, and their influenced factors were also discussed. The results showed that April was the earlier stage of HAB breaking out, and diatom was the dominant species; while Dinoflagellate became the dominant species when large-scale HAB broke out in May. The concentrations of DIN and PO4(3-) -P decreased significantly from April to May. The Mean value of DIN decreased from 18.04 to 10.80 micromol x L(-1), its decline rate was 40%. As for PO4(3-) -P, its Mean value decreased from 0.47 to 0.27 micromol x L(-1), and its decline rate was 43%. This phenomenon indicated the significant depletion of nutrients by harmful algae in the process. However, the primary species of HABs in ECS was dinoflagellates in May. Since dinoflagellates did not consume SiO3(2-) -Si during the breed, as well as the supplement from Changjiang Diluted Water, the mean value of SiO3(2-) -Si increased slightly from 16. 15 to 16.96 micromol x L(11) in the researched area. The Mean value of DO decreased from 8.76 to 6.09 mg x L(-1) from April to May, because the effect of temperature to DO was more obvious than that of phytoplankton photosynthesis. The temperature was higher in May, and the solubility of oxygen decreased with increasing temperature, therefore, the concentration of DO was lower after the Harmful algal blooms. PMID:23947028
Li, Hong-Mei; Shi, Xiao-Yong; Chen, Peng; Zhang, Chuan-Song
Harmful Algal Blooms (HAB's) are a major concern all over the world due to their negative impacts on the marine environment, human health, and the economy. Their detection from space still remains a challenge particularly in turbid coastal waters. In this study we propose a simple reflectance band difference approach for use with Medium Resolution Imaging Spectrometer (MERIS) data to detect intense plankton blooms. For convenience we label this approach as the Extreme Bloom Index (EBI) which is defined as EBI = Rrs (709) - Rrs (665). Our initial analysis shows that this band difference approach has some advantages over the band ratio approaches, particularly in reducing errors due to imperfect atmospheric corrections. We also do a comparison between the proposed EBI technique and the Maximum Chlorophyll Index (MCI) Gower technique. Our preliminary result shows that both the EBI and MCI indeces detect intense plankton blooms, however, MCI is more vulnerable in highly scattering waters, giving more positive false alarms than EBI.
Amin, R.; Gilerson, A.; Gould, R.; Arnone, R.; Ahmed, S.
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.
We present a simple algorithm to identify Karenia brevis blooms in the Gulf of Mexico along the west coast of Florida in satellite imagery. It is based on an empirical analysis of collocated matchups of satellite and in situ measurements. The results of this Empirical Approach is compared to those of a Bio-optical Technique – taken from the published literature – and the Operational Method currently implemented by the NOAA Harmful Algal Bloom Forecasting System for K. brevis blooms. These three algorithms are evaluated using a multi-year MODIS data set (from July, 2002 to October, 2006) and a long-term in situ database. Matchup pairs, consisting of remotely-sensed ocean color parameters and near-coincident field measurements of K. brevis concentration, are used to assess the accuracy of the algorithms. Fair evaluation of the algorithms was only possible in the central west Florida shelf (i.e. between 25.75°N and 28.25°N) during the boreal Summer and Fall months (i.e. July to December) due to the availability of valid cloud-free matchups. Even though the predictive values of the three algorithms are similar, the statistical measure of success in red tide identification (defined as cell counts in excess of 1.5 × 104 cells L?1) varied considerably (sensitivity—Empirical: 86%; Bio-optical: 77%; Operational: 26%), as did their effectiveness in identifying non-bloom cases (specificity—Empirical: 53%; Bio-optical: 65%; Operational: 84%). As the Operational Method had an elevated frequency of false-negative cases (i.e. presented low accuracy in detecting known red tides), and because of the considerable overlap between the optical characteristics of the red tide and non-bloom population, only the other two algorithms underwent a procedure for further inspecting possible detection improvements. Both optimized versions of the Empirical and Bio-optical algorithms performed similarly, being equally specific and sensitive (~70% for both) and showing low levels of uncertainties (i.e. few cases of false-negatives and false-positives: ~30%)—improved positive predictive values (~60%) were also observed along with good negative predictive values (~80%).
Carvalho, Gustavo A.; Minnett, Peter J.; Banzon, Viva F.; Baringer, Warner; Heil, Cynthia A.
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)
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
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
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
Harmful algal blooms (HABs), including toxic species, have been increasing in frequency, range, and duration over the past several decades. The effect of a harmful or toxic algal diet on zooplankton nutrient regeneration, however, has not been previously examined. In this study, we determined the effects of non-bloom and bloom concentrations of non-toxic and toxic cultures of HAB species Prorocentrum
Grace K. Saba; Deborah K. Steinberg; Deborah A. Bronk
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
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.
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.
In the report it is shown that novel algal blooms in eutrophicated areas can be the result of major shifts in N/P or ammonium/nitrate ratios rather than a general nutrient enrichment. The statement is based on the results of a study on the impact of eutro...
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).
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
The Ontario Ministry of the Environment provides an algal identification service as part of the Ministry's response to algal bloom events, and we have been tracking the reports since 1994. From 1994 through 2009, we noted a significant increase in the number of algal blooms reported each year (P < 0.001). There was also an increase in the number of
Jennifer G. Winter; Anna M. DeSellas; Rachael Fletcher; Lucja Heintsch; Andrew Morley; Lynda Nakamoto; Kaoru Utsumi
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
The global increase in frequency and intensity of harmful algal blooms (HABs) has led to more frequent incidence of seafood-borne illnesses and adverse impacts on natural resources. In response, public health agencies worldwide have mobilized to initiate HAB monitoring programs. To meet this demand, innovative analytical techniques are being developed that provide rapid and reliable detection of the causative organisms and the toxins produced. Modifications to conventional chromatography and mass spectrometry have greatly improved sensitivity and selectivity of these methods toward naturally occurring phycotoxins. Bioassay techniques using live organisms are giving way to molecular and cellular methods that measure the toxicologically significant activity of the toxin molecules. Molecular probes are being applied to distinguish species-specific RNA and DNA sequences for rapid identification of HAB-causing organisms. The direction of this new technology is to develop rapid and reliable screening methods for phycotoxins and the causative organisms to provide protection for public health, aquaculture, and natural resources. New methods also are being developed for detecting minute amounts of toxin molecules in microenvironments, leading to understanding the toxicokinetics and toxicological functions of the toxins. PMID:11351396
Pierce, R H; Kirkpatrick, G J
In this work we explore the statistical features of monthly ensembles and their capability to predict biogeochemical conditions in the Baltic Sea. Operational marine environmental modelling has been considered hard, and consequently there are very few operational ecological models. Operational modelling of harmful algal blooms is harder still, since it is difficult to separate the algal species in models, and in general, very little is known of HAB properties. We present results of an ensemble approach to HAB forecasting in the Baltic, and discuss the applicability of the forecasting method to biochemical modelling. It turns out that HABs are indeed possible to forecast with useful accuracy. For modelling the algal blooms in Baltic Sea we used FMI operational 3-dimensional biogeochemical model to produce seasonal ensemble forecasts for different physical, chemical and biological variables. The modelled variables were temperature, salinity, velocity, silicate, phosphate, nitrate, diatoms, flagellates and two species of potentially toxic filamentous cyanobacteria nodularia spumigena and aphanizomenon flos-aquae. In this work we concentrate to the latter two. Ensembles were produced by running the biogeochemical model several times and forcing it on every run with different set of seasonal weather parameters from ECMWF's mathematically perturbed ensemble prediction forecasts. The ensembles were then analysed by statistical methods and the median, quartiles, minimum and maximum values were calculated for estimating the probable amounts of algae. Validation for the forecast method was made by comparing the final results against available and valid in-situ HAB data.
Roiha, Petra; Westerlund, Antti; Stipa, Tapani
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
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
Florida Bay is Florida’s (USA) largest estuary and has experienced harmful picocyanobacteria blooms for nearly two decades.\\u000a While nutrient loading is the most commonly cited cause of algal blooms in Florida Bay, the role of zooplankton grazing pressure\\u000a in bloom occurrence has not been considered. For this study, the spatial and temporal dynamics of cyanobacteria blooms, the\\u000a microbial food web,
Jennifer A. Goleski; Florian Koch; Maria A. Marcoval; Charles C. Wall; Frank J. Jochem; Bradley J. Peterson; Christopher J. Gobler
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
Detection of harmful algal blooms in Case II hypereutrophic aquaculture systems continues to be a challenge. Attempts to isolate certain pond constituents have been difficult because both organic matter and suspended sediments can mask detection of these components. A three band reciprocal reflectan...
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. PMID:20628532
Stumpf, Richard P; Tomlinson, Michelle C; Calkins, Julie A; Kirkpatrick, Barbara; Fisher, Kathleen; Nierenberg, Kate; Currier, Robert; Wynne, Timothy T
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.
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.
The Earth and the oceans have warmed significantly over the past four decades, providing evidence that the Earth is undergoing\\u000a long-term climate change. Increasing temperatures and changing rainfall patterns have been documented. Cyanobacteria have\\u000a a long evolutionary history, with their first occurrence dating back at least 2.7 billion years ago. Cyanobacteria often dominated\\u000a the oceans after past mass extinction events.
Valerie J Paul
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
Nutrient inputs to streams and lakes, primarily from anthropogenic sources, lead to eutrophic conditions that favor algal blooms with undesirable consequences. In contrast, low nutrient or oligotrophic waters rarely support algal blooms; such ecosystems are typically lower in productivity. Since the mid-1980’s however, the diatom Didymosphenia geminata has dramatically expanded its range colonizing oligotrophic rivers worldwide with blooms appearing as thick benthic mats. This recent global occurrence of Didymosphenia geminata blooms in temperate rivers has been perplexing in its pace of spread and the paradoxical nature of the nuisance growths. The blooms occur primarily in oligotrophic flowing waters, where phosphorus (P) availability often limits primary production. We present a biogeochemical process by which D. geminata mats adsorb both P and iron (Fe) from flowing waters and make P available for cellular uptake. The adsorbed P becomes bioavailable through biogeochemical processes that occur within the mat. The biogeochemical processes observed here while well accepted in benthic systems are novel for algal blooms in lotic habits. Enzymatic and bacterial processes such as Fe and sulfate reduction can release the adsorbed P and increase its bioavailability, creating a positive feedback between total stalk biomass and nutrient availability. Stalk affinity for Fe, Fe-P biogeochemistry, and interaction between watershed processes and climatic setting explain the paradoxical blooms, and the recent global spread of this invasive aquatic species. At a broader scale the study also implies that such algal blooms in oligotrophic environments can fundamentally alter the retention and longitudinal transfer of important nutrients such as P in streams and rivers.
Sundareshwar, P. V.; Upadhyay, S.; Abessa, M. B.; Honomichl, S.; Berdanier, B.; Spaulding, S.; Sandvik, C.; Trennepohl, A.
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
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.
During February–April 2008, an unusual mortality event occurred in Texas coastal waters that resulted in over 100 bottlenose dolphin (Tursiops truncatus) deaths. This mortality event overlapped spatially and temporally with a harmful algal bloom (HAB) composed of the toxin-producing genera Dinophysis spp. and Prorocentrum spp., and was associated with shellfish bed closures due to HAB toxins. A bloom of the
Spencer E. Fire; Zhihong Wang; Meridith Byrd; Heidi R. Whitehead; Jeff Paternoster; Steve L. Morton
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
Mandovi and Zuari estuarine complex is monsoon-influenced estuaries located along the central west coast of India. During the past few years, there has been an increase in nutrient loading specially during monsoonal runoff which is responsible for the growth of harmful algal flora. To understand occurrence and distribution of harmful algal blooms species, daily/alternate day samplings were carried out in Mandovi and Zuari estuaries during 2007-2008 and 2008-2009 periods, respectively, comprising of monsoon (June–November) and nonmonsoon (December–May). In Mandovi, total 54 HAB species with 49 in monsoon and 36 during nonmonsoon period were reported. In Zuari, total 46 HAB species with 38 in monsoon and 41 were reported during nonmonsoon period. Bray-Curtis cluster analysis based on log-transformed phytoplankton density detected seven well-defined groups revealing spatiotemporal variability. The density of the dominant harmful algal species was significantly positively correlated with nutrients, but negatively correlated with salinity. The results of the study indicate that monsoon plays an important role in occurrence and distribution of harmful algal species having direct correlation with salinity variations and nutrient loading.
Pednekar, Suraksha M.; Prabhu Matondkar, S. G.; Kerkar, Vijaya
Cyanobacterial harmful algal blooms (CHAB) are notorious for depleting dissolved oxygen level, producing various toxins, causing threats to aquatic life, altering the food-web dynamics and the overall ecosystem functioning in inland lakes, estuaries, and coastal waters. Most of these algal blooms produce various toxins that can damage cells, tissues and even cause mortality of living organisms. Frequent monitoring of water quality in a synoptic scale has been possible by the virtue of remote sensing techniques. In this research, we present a novel technique to monitor CHAB using remote sensing reflectance products. We have modified a multi-band quasi analytical algorithm that determines phytoplankton absorption coefficients from above surface remote sensing reflectance measurements using an inversion method. In situ hyperspectral remote sensing reflectance data were collected from several highly turbid and productive aquaculture ponds. A novel technique was developed to further decompose the phytoplankton absorption coefficients at 620 nm and obtain phycocyanin absorption coefficient at the same wavelength. An empirical relationship was established between phycocyanin absorption coefficients at 620 nm and measured phycocyanin concentrations. Model calibration showed strong relationship between phycocyanin absorption coefficients and phycocyanin pigment concentration (r2=0.94). Validation of the model in a separate dataset produced a root mean squared error of 167 mg m-3 (phycocyanin range: 26-1012 mg m-3). Results demonstrate that the new approach will be suitable for quantifying phycocyanin concentration in cyanobacteria dominated turbid productive waters. Band architecture of the model matches with the band configuration of the Medium Resolution Imaging Spectrometer (MERIS) and assures that MERIS reflectance products can be used to quantify phycocyanin in cyanobacterial harmful algal blooms in optically complex waters.
Mishra, S.; Mishra, D. R.; Tucker, C.
Dissolved oxygen characteristics of spring algal bloom in Xiangxi Bay of Three Gorges Reservoir were studied. In surveys, 12 stations have been investigated and 132 samples were collected weekly from February 24 to May 10 in 2008. Chlorophyll a, pH and water temperature could be the significant influence factors to dissolved oxygen in spring algal bloom by using stepwise multiple
Huajun Luo; Defu Liu; Daobin Ji; Yingping Huang
Cholera has been long associated with the seasonality of coastal algal blooms off Bangladesh. Using fluorescent antibody (FA) techniques, microbiologists have now identified a viable, non-cultivable form of Vibrio cholerae in a wide range of marine life, including cyanobacteria (Anabaena variabilis), diatoms (Skeletonema costatum), phaeophytes (Ascophyllum nodosum), in copepod molts, and in freshwater vascular aquatic plants (water hyacinths and duckweed). In unfavourable conditions V. cholerae assumes spore-like forms; with proper nutrients, pH and temperature, it reverts to a readily transmissible and infectious state. Nitrates and phosphates in sewage and fertilizers cause eutrophication, and scientists report an increase in intensity, duration and shifts in the biodiversity of algal blooms in many coastal, brackish and fresh waters worldwide. V. cholerae has been isolated from phyto- and zooplankton in marine and fresh waters near Lima, Peru. V. cholera 01, biotype El Tor, serotype Inaba, may have arrived in the Americas in the bilge of a Chinese freighter. There, in the abundant coastal sea life along the Latin American Pacific coast, nourished by the Humboldt current and eutrophication, it found a reservoir for surviving unfavourable conditions. It is hypothesized that the algae and Vibrio populations grew exponentially; consumed by fish, mollusks and crustacea, a heavy 'inoculum' of carriers infected with V. cholerae was generated and transported into multiple coastal communities. PMID:8155853
Epstein, P R
We have investigated the characteristics of algal blooms in relation to the marine environment since their first known occurrence in the southern coastal waters of Korea. The algal blooms occurred most frequently in Masan and Jinahe bays, suggesting that they were related to the development of anoxic water masses. Skeletonema costatum, Heterosigma akashiwo and Prorocentrum sp. commonly occurred as the dominant organisms causing the blooms in all regions, although the conditions of their appearance differed from place to place. Algal blooms in all regions were more likely to occur when precipitation ten days prior to the bloom was greater than the long-term mean values. However, the factors that relate to the development of the algal blooms in Gamak Bay differed depending upon the causative species while they were largely identical in Jinhae Bay, regardless of the species. PMID:17983649
Lee, Moon-Ock; Kim, Jong-Kyu
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
The algal blooming in the inland lakes has become a critically important issue for its impacts not only on local natural and social environments, but also on global human community. However, the occurrences of blooming on larger spatial scale and longer time scale have rarely been studied. As the third largest freshwater lake in China, Lake Taihu has drawn increasing attention from both public and scientific communities concerning its degradation. Using available satellite images, we reconstructed the spatial and temporal patterns of algal blooms in Lake Taihu through the pasttwo decades. The blooming characteristics over the past two decades were examined with the dynamic of initial blooming date being highlighted. The initial blooming dates were gradually becoming later and later from 1987 to 1997. Since 1998, however, the initial blooming date came earlier and earlier year by year, with approximately 11.42 days advancement per year. From 1987 to 2007, the annual duration of algal blooms lengthened year by year, in line with the substantial increases in the occurrences of algal blooms in spring and summer months. The algal blooms usually occur in northern bays and spread to center and south parts of Lake Taihu. The increases in previous winter's mean daily minimum temperature partially contributed to the earlier blooming onset. However, human activities, expressed as total gross domestic product (GDP) and population, outweighed the climatic contribution on the initial blooming date and blooming duration. This study may provide insights for the policy makers who try to curb the algal blooming and improve the water quality of inland freshwater lakes. PMID:19544849
Duan, Hongtao; Ma, Ronghua; Xu, Xiaofeng; Kong, Fanxiang; Zhang, Shouxuan; Kong, Weijuan; Hao, Jingyan; Shang, Linlin
A simple technique to predict the future occurrence of algal blooms was evaluated for seven test lake systems proximate to Syracuse, NY during the summer of 1978 and 1979. The selected test systems represent a broad range of trophic status, from mesotrophic to hypereutrophic. The technique includes a simple filtering process followed by the identification of the color imparted to the filter, based on comparison to National Bureau of Standards' color chips. The reference measure of phytoplankton standing crop was chlorophyll-a. Particular colors of filtered particulates were not demonstrated to be useful estimators of chlorophyll-a concentration, though the hues olive and yellow-green were associated with higher chlorophyll-a levels. The particulate color method was demonstrated to be useful in following certain physical/chemical changes in a lake.
Litten, S.; Effler, S.W.; Meyer, M.
This paper analyses the relation between data measured in situ and the NDVI derived from AVHRR of NOAA-14 during algal bloom in the Bohai sea in 1998 to establish surface biomass model of Ceratium furca(EHr.). This model is easy to utilize data received from multi-source satellite in operation, and gets directly the index of phytoplankton biomass. The area and distribution of high biomass is also presented. Based on this model, propagation speed of phytoplankton reveals progress of algal bloom development. The result of this model can discriminate algal bloom water from silt or suspended particle material (SPM).
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.
This study was conducted to gain insight into the characteristics of algal blooms in relation to the marine environment of\\u000a Gamak Bay. From the first known occurrence of algal blooms in 1984 until 2006, 23 causal species have been identified, the\\u000a most common ones being Prorocentrum sp., Cochlodinium polykrikoides, Chaetoceros sp., Skeletonema costatum, and Heterosigma akashiwo. A principal component analysis
Moonock Lee; Byeongkuk Kim; Yeongah Kwon; Jongkyu Kim
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
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
In this paper, an integrated numerical and fuzzy cellular automata model was developed to predict possible algal blooms in Dutch coastal waters basing on the irradiance, nutrients and neighbourhood conditions. The numerical module used Delft3D-WAQ to compute the abiotic conditions, and fuzzy cellular automata approach was applied to predict the algal biomass that was indicated by chlorophyll a concentration. The
Qiuwen Chen; Arthur E. Mynett
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
According to the survey conducted from winter and spring algal blooms, the changes of water quality and characteristics of Daning River of Three Gorges Reservoir (TGR) were studied. The results suggested that during the period of winter algal blooms centered on Tangjia bay in Daning river, chlorophyll a (Chl-a) had a wide range (the rates of (Chl-a)max and (Chl-a)min is 260). The contents of total nitrogen (TN), total phosphorus (TP) and potassium permanganate index were at very high levels because of bioaccumulation from algal blooms, but the values of dissolved oxygen (DO) and pH were very low. During winter algal blooms fastigium poor algae were observed accounting for 2 phylum 4 species, dominant species are Microcystis aeruginosa and Microcystis flos-aquae, the maximum value of algal density was 3.15 x 10(7) cells/L, and the correlation weighted nutrition state index was 80, which indicated water body was at high eutrophication level. However the spring algal blooms belonged to whole watershed outbreak, the values of Chl-a, TN, TP and potassium permanganate index became all markedly high with outbreak of algal blooms. There were 5 phylum 44 species algae being observed during spring algal blooms fastigium, different sections observed different dominant species and algal density values. The correlation weighted nutrition state index showed water of Dongping bar and Baishui River sections was at slight eutrophication level. During winter algal blooms there were significantly positive correlations between Chl-a and TN, TP, potassium permanganate index, water temperature, between pH and SD. Significantly negative correlations were observed between Chl-a and DO, SD, between pH and TN, TP, potassium permanganate index. In spring algal blooms significantly positive correlations were observed between Chi-a and TP, potassium permanganate index, DO, pH, between pH and Chla, TP, potassium permanganate index, DO, air temperature. Significantly negative correlations were observed between Chl-a and SD, between pH and SD. PMID:20187374
Cao, Cheng-jin; Zheng, Bing-hui; Zhang, Jia-lei; Huang, Min-sheng; Chen, Zhen-lou
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
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
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.
Tobin, Elizabeth D.; Grunbaum, Daniel; Patterson, Johnathan; Cattolico, Rose Ann
The Earth and the oceans have warmed significantly over the past four decades, providing evidence that the Earth is undergoing long-term climate change. Increasing temperatures and changing rainfall patterns have been documented. Cyanobacteria have a long evolutionary history, with their first occurrence dating back at least 2.7 billion years ago. Cyanobacteria often dominated the oceans after past mass extinction events.
Valerie J Paul
The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms (HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that the B. plicatilis obtained sufficient nutrition from Prorocentrum donghaiense to support net population increase. With exposure to 2.5×104 cells mL-1 of P. donghaiense, the number of B. plicatilis increased faster than it did when exposed to other four algal densities (5, 10, 15 and 20 ×104 cells mL-1), and the increase rate of B. plicatilis population ( r) at this algal density was 0.104 ± 0.015 rd-1. Cell densities of P. donghaiense decreased due to the grazing of B. plicatilis. In contrast, Heterosigma akashiwo had an adverse effect on B. plicatilis population and its growth was largely unaffected by rotifer grazing. In this case, B. plicatilis population decreased and H. akashiwo grew at a rate similar to that of the control.
Xie, Zhihao; Xiao, Hui; Tang, Xuexi; Cai, Hengjiang
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
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
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
The long-term effects (>1 year) of a naturally occurring toxic plankton bloom (Karenia brevisulcata) on subtidal benthic macroinvertebrate communities were investigated in Wellington Harbour, a semi-enclosed temperate embayment in New Zealand. For 3 years communities were sampled at three different sites in the harbour. Analyses revealed that community recovery following the bloom was site-specific. Multivariate analyses indicated that at one site community composition was approaching recovery ˜3 years post-bloom. At the second site, a sequential recovery process was indicated, whereas at the third site the community composition oscillated from year to year, but did not show any signs of a sequential recovery process. The nature of the hydrodynamic regime was identified as a major factor influencing the observed recovery processes. Communities exposed to an active hydrodynamic regime were less affected by the bloom and differed little in their composition pre- and post-bloom, as they were naturally in a perpetual state of recovery as indicated by a dominance of r-selected species. The community at the hydrodynamically less active site was more affected by the bloom and exhibited temporal differences in composition consistent with successional models. Complete recovery to a pre-disturbance climax community dominated by K-selected species is likely to take 4 5 years, if not interrupted by other disturbances. Given the increased occurrence of harmful algal blooms worldwide, more monitoring and manipulative studies are needed to further evaluate the effects of such disturbances on macrobenthic communities.
Kröger, Kerstin; Gardner, Jonathan P. A.; Rowden, Ashley A.; Wear, Robert G.
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,
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
Recent observations that viruses are very abundant and biologically active components in marine ecosystems suggest that they probably influence various biogeochemical and ecological processes. In this study, the population dynamics of the harmful bloom-forming phytoplankton Heterosigma akashiwo (Raphidophyceae) and the infectious H. akashiwo viruses (HaV) were monitored in Hiroshima Bay, Japan, from May to July 1998. Concurrently, a number of H. akashiwo and HaV clones were isolated, and their virus susceptibilities and host ranges were determined through laboratory cross-reactivity tests. A sudden decrease in cell density of H. akashiwo was accompanied by a drastic increase in the abundance of HaV, suggesting that viruses contributed greatly to the disintegration of the H. akashiwo bloom as mortality agents. Despite the large quantity of infectious HaV, however, a significant proportion of H. akashiwo cells survived after the bloom disintegration. The viral susceptibility of H. akashiwo isolates demonstrated that the majority of these surviving cells were resistant to most of the HaV clones, whereas resistant cells were a minor component during the bloom period. Moreover, these resistant cells were displaced by susceptible cells, presumably due to viral infection. These results demonstrated that the properties of dominant cells within the H. akashiwo population change during the period when a bloom is terminated by viral infection, suggesting that viruses also play an important role in determining the clonal composition and maintaining the clonal diversity of H. akashiwo populations. Therefore, our data indicate that viral infection influences the total abundance and the clonal composition of one host algal species, suggesting that viruses are an important component in quantitatively and qualitatively controlling phytoplankton populations in natural marine environments. PMID:11055943
Tarutani, K; Nagasaki, K; Yamaguchi, M
Edna Graneli and Jefferson T. Turner, Editors;Ecological Studies Series, Vol. 189; Springer; ISBN 3540322094; 413 pp.; 2006; $195 Harmful algal blooms (HABs) affect commercially and recreationally important species, human health, and ecosystem functioning. Hallmark events are the visually stunning blooms where waters are discolored and filled with ichthyotoxin-producing algae that lead to large fish kills. Of most concern, however, are
Daniel L. Roelke
The present study involves analyzing chlorophyll-a (Chl-a) from SeaWiFS data collected over the period 1998-2002 to better understand the spatial and temporal aspects of red tide algal blooms created by Cochlodinium polykrikoides species in the enclosed and semi-enclosed bays of the South Sea of Korea. NOAA-AVHRR data is analyzed for sea surface temperature (SST) to elucidate physical factors affecting these
Shanmugam PALANISAMY; Yu-Hwan Ahn; Joo-Hyung Ryu; Jeong-Eon Moon
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
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
Phytoplankton primary production and its environmental regulation were examined at 3 stations representative of the lower Neuse River Estuary near the Pamlico Sound interface. This study covered a 3-year period (November 1987-October 1990). The authors also examined the roles of the major phytoplankton nutrients nitrogen and phosphorus in controlling growth and bloom formation. The overall potential for nuisance blooms and associated episodes of bottom water hypoxia and anoxia was investigated in field studies. Algal biomass and production varied seasonally, with high values in summer and low values in winter. In situ nutrient addition bioassays indicated the estuary experienced a general state of N limitation with especially profound limitation during summer periods. The authors recommendations for a management strategy include reductions in Dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and suspended sediment loads in order to maintain the system in a nuisance bloom-free condition.
Paerl, H.W.; Mallin, M.; Rudek, J.; Bates, P.W.
Extreme population fluctuations, or outbreaks, are driven by interacting processes that are often more complex than isolated changes in consumer or resource control. Blooms of the macroalga Caulerpa sertularioides in the eastern tropical Pacific overgrew and killed reef-building corals, with blooms onto reefs corresponding to cool La Niña phases of inter-decadal fluctuations of the El Niño-Southern Oscillation. We quantified factors responsible for the maintenance of C. sertularioides patches in off-reef areas, namely an associational mutualism with an epiphytic cyanobacteria (Lyngbya majuscula), coupled with spatial refuges at the scales of individual thalli and habitat. Maintenance of near reef algal populations with a strong response to nutrient addition showed that these populations were primed to bloom onto reefs in response to enhanced nutrient delivery, such as those potentially associated with La Niña conditions. However, our experiments demonstrated that no single factor related to consumer or resource control was likely to stimulate bloom formation in isolation. Rather, we propose a novel model of reef bloom formation where off-reef blooms are sustained by processes reducing consumer control, and then bloom onto reefs through an interaction between increased allochthonous nutrient input and an uncoupling of consumer control by an association with epiphytic cyanobacteria. PMID:20593199
Smith, Tyler B; Fong, Peggy; Kennison, Rachel; Smith, Jayson
It is well established that cyst-forming phytoplankton species are transported in ships' ballast tanks. However, there is increasing evidence that other phytoplankton species which do not encyst are also capable of surviving ballast transit. These species have alternative modes of nutrition (hetero- or mixotrophy) and/or are able to survive long-term darkness. In our studies of no-ballast-on-board vessels arriving in the Great Lakes, we tested for the presence of the harmful algal bloom species Aureococcus anophagefferens (brown tide) in residual (i.e., unpumpable) ballast water using methods based on the PCR. During 2001, the brown tide organism was detected in 7 of 18 ballast water tanks in commercial ships following transit from foreign ports. Furthermore, it was detected after 10 days of ballast tank confinement during a vessel transit in the Great Lakes, a significant result given the large disparity between the salinity tolerance for active growth of Aureococcus (>22 ppt) and the low salinity of the residual ballast water (approximately 2 ppt). We also investigated the potential for smaller, recreational vessels to transport and distribute Aureococcus. During the summer of 2002, 11 trailered boats from the inland bays of Delaware and coastal bays of Maryland were sampled. Brown tide was detected in the bilge water in the bottoms of eight boats, as well as in one live-well sample. Commercial ships and small recreational boats are therefore implicated as potential vectors for long-distance transport and local-scale dispersal of Aureococcus. PMID:15528511
Doblin, Martina A; Popels, Linda C; Coyne, Kathryn J; Hutchins, David A; Cary, S Craig; Dobbs, Fred C
Harmful (toxic, food web altering, hypoxia generating) cyanobacterial algal blooms (CyanoHABs) are proliferating world-wide due to anthropogenic nutrient enrichment, and they represent a serious threat to the use and sustainability of our freshwater resources. Traditionally, phosphorus (P) input reductions have been prescribed to control CyanoHABs, because P limitation is widespread and some CyanoHABs can fix atmospheric nitrogen (N(2)) to satisfy their nitrogen (N) requirements. However, eutrophying systems are increasingly plagued with non N(2) fixing CyanoHABs that are N and P co-limited or even N limited. In many of these systems N loads are increasing faster than P loads. Therefore N and P input constraints are likely needed for long-term CyanoHAB control in such systems. Climatic changes, specifically warming, increased vertical stratification, salinization, and intensification of storms and droughts play additional, interactive roles in modulating CyanoHAB frequency, intensity, geographic distribution and duration. In addition to having to consider reductions in N and P inputs, water quality managers are in dire need of effective tools to break the synergy between nutrient loading and hydrologic regimes made more favorable for CyanoHABs by climate change. The more promising of these tools make affected waters less hospitable for CyanoHABs by 1) altering the hydrology to enhance vertical mixing and/or flushing and 2) decreasing nutrient fluxes from organic rich sediments by physically removing the sediments or capping sediments with clay. Effective future CyanoHAB management approaches must incorporate both N and P loading dynamics within the context of altered thermal and hydrologic regimes associated with climate change. PMID:21345482
Paerl, Hans W; Hall, Nathan S; Calandrino, Elizabeth S
Fluorescence excitation-emission matrix spectroscopy (EEMS) was employed to characterize the dissolved organic matter (DOM) in algal bloom seawater of Jiaozhou Bay in February, 2004. The relationships of DOM fluorescence characteristics with phytoplankton multiplication, dissolved organic carbon (DOC), salinity, dissolved oxygen and pH were discussed. In addition, the protein-like and humic-like fluorescence changes fore and aft cross-flow ultrafiltration (CFF) were primarily evaluated. The results show that the intensities of high and low-excitation protein-like fluorescence, which have the same sources, are stronger than that of humic-like during algal bloom. Both correlations between protein-like fluorescence intensities and chlorophyll-a and between humic-like fluorescence intensities and chlorophyll-a are relevant to the phytoplankton multiplication. As a whole, the fluorescence intensities of protein-like and humic-like increases with chlorophyll-a increasing. Furthermore the ratios of new to old DOM increase with phytoplankton biomass increasing. Good positive correlations between protein-like fluorescence intensities and DOC and between the ratios of protein-like to humic-like fluorescence intensities and DOC suggest that the DOC is mainly composed of newly produced matter during algal bloom. Some inorganic factors, such as salinity, dissolved oxygen and pH, have little effects on protein-like and humic-like fluorescence. Fore and aft the CFF experiments, the positions of protein-like and humic-like fluorescence peaks have little alteration, the balance of fluorescence intensity is not so good as organic carbon mass balance as a whole. Fluorescence balance should be used only as a supplementary technique for evaluating contaminations or loss by organic carbon mass balance. PMID:16686185
Ji, Nai-yun; Zhao, Wei-hong; Wang, Jiang-tao; Cui, Xin; Miao, Hui
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
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
A moored optical buoy was deployed in the Pearl River estuarine waters for a 15-day period. A four-day algal bloom event occurred during this study period. Both chlorophyll a concentration and algal cell density (a proxy for biomass) changed dramatically before and after the event. The chlorophyll concentration at a 2.3m depth rose from 5.15mg\\/m?3 at 15:00h on August 19
Jun Zhao; Wenxi Cao; Yuezhong Yang; Guifen Wang; Wen Zhou; Zhaohua Sun
Nutrient and hydrologic conditions strongly influence harmful planktonic and benthic cyanobacterial bloom (CHAB) dynamics\\u000a in aquatic ecosystems ranging from streams and lakes to coastal ecosystems. Urbanization, agricultural and industrial development\\u000a have led to increased nitrogen (N) and phosphorus (P) discharge, which affect CHAB potentials of receiving waters. The amounts,\\u000a proportions and chemical composition of N and P sources can influence
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
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.
Research into the development of an Early Warning Harmful Algae Bloom (HAB) Sensing System for use in Underwater Monitoring Applications is presented. The sensor proposed by the authors utilises the complex ties between ocean colour, absorption and scattering, along with algae pigmentation. The objective is to develop a robust inexpensive sensor for use in an early warning system for the detection and possible identification of Harmful Algae Blooms. The sensing mechanism utilised in this system is based on a combination of absorption and reflection spectroscopy and Principle Component Analysis (PCA) signal processing. Spectroscopy is concerned with the production, measurement, and interpretation of electromagnetic spectra arising from either emission or absorption of radiant energy by various substances (or HABs in this application). Preliminary results are presented from the interrogation of chlorophyll, yeast and saline solutions, as well as levels of absorption obtained utilising two dyes Blue (brilliant Blue (E133) and Carmoisine (E122) mix) and Red (Ponceau (E124) and Sunset yellow (E110) mix).
O'Connell, Eoin; Lyons, William; Sheridan, Cormac; Lewis, Elfed
The natural process of eutrophication is accelerated by human activities worldwide that interrupt nutrient biogeochemical cycles. Three algal bloom events have been monitored in the northern tributary of the Jiulong River since 2009. The inflection points in a robust locally-weighted regression analysis (LOESS) of the relationship between TN and TP concentrations in the river water, and a TN:TP comparison with nutrient source loadings, suggested that both external loading and internal nutrient cycling contributed to these algal blooms. Nutrient release from the sediments may have played an important role in regulating the nutrients in the overlying water column. In particular, excessive nutrient inputs from various sources and ubiquitous river damming caused further accumulation of the nutrient loading. In-situ autochthonous primary production was enhanced in this relatively stable "river" to "lake" water body. Thus, attention must be paid to the effects of river damming and the consequent internal nutrient release. PMID:21377176
Li, Ying; Cao, Wenzhi; Su, Caixia; Hong, Huasheng
A new bio-optical algorithm has been developed to provide accurate assessments of chlorophyll a (Chl a) concentration for detection and mapping of algal blooms from satellite data in optically complex waters, where the presence of suspended sediments and dissolved substances can interfere with phytoplankton signal and thus confound conventional band ratio algorithms. A global data set of concurrent measurements of pigment concentration and radiometric reflectance was compiled and used to develop this algorithm that uses the normalized water-leaving radiance ratios along with an algal bloom index (ABI) between three visible bands to determine Chl a concentrations. The algorithm is derived using Sea-viewing Wide Field-of-view Sensor bands, and it is subsequently tuned to be applicable to Moderate Resolution Imaging Spectroradiometer (MODIS)/Aqua data. When compared with large in situ data sets and satellite matchups in a variety of coastal and ocean waters the present algorithm makes good retrievals of the Chl a concentration and shows statistically significant improvement over current global algorithms (e.g., OC3 and OC4v4). An examination of the performance of these algorithms on several MODIS/Aqua images in complex waters of the Arabian Sea and west Florida shelf shows that the new algorithm provides a better means for detecting and differentiating algal blooms from other turbid features, whereas the OC3 algorithm has significant errors although yielding relatively consistent results in clear waters. These findings imply that, provided that an accurate atmospheric correction scheme is available to deal with complex waters, the current MODIS/Aqua, MERIS and OCM data could be extensively used for quantitative and operational monitoring of algal blooms in various regional and global waters.
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
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
Since 1998 unusual algal blooms of different toxic Raphidophyte species have been observed during April and beginning of May in the northeastern part of the North Sea including the Skagerrak as well as in the Kattegatt region. The algal blooms of Raphidophytes took place after the spring bloom, which normally occurs in this area during March, but before the anually reoccurring bloom of Phaeocystis, which usually is observed during May, when water temperatures exceed 15°C. The Raphidophyte blooms were mainly represented by two different Chattonella species and by Heterosigma akashiwo. The toxic algal blooms which have been identified in 1998, 2000 and 2001 can appear with maximum cell numbers of 24 mill. Cells/l (Backe-Hansen, 1999) and Chlorophyll values up to 80 ?g/l. Satellite images of MOS and SeaWiFs show the beginning of the blooms west of Jutland (Denmark) and apparently were advected with the Jutland current towards the northeast. Later, the Raphidophyte blooms were observed along the Swedish and Norwegian west coast and extended along the Norwegian south coast up to 6°East, following the extensions of the Baltic current. The causative species of blooms, Chattonella sp., has shown strong phototactic behavior. In addition to 19'-butanoyloxyfucoxanthin, the Chattonella sp. contains three kind of carotenoids which other species do not have. Thus, the observations from microscopy and pigment profile from HPLC suggest that this species in the German Bight should be considered as a new HAB species. The reoccurrence of Chattonella blooms may indicate the response of algae to some kind of environmental change in the North Sea. Determination of the extend and the advection of toxic microalgae blooms as well as predictions through satellite remote sensing in the coastal areas of Denmark, Sweden and southern Norway, is also of great economic importance for the extensive mariculture ventures in this region, which repeatedly have suffered from the effects of toxic algal blooms.
Lu, Douding; Goebel, Jeanette; Hetscher, Matthias; Horstmann, U.; Davidov, Alexander
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.
Nutrient and hydrologic conditions strongly influence harmful planktonic and benthic cyanobacterial bloom (CHAB) dynamics in aquatic ecosystems ranging from streams and lakes to coastal ecosystems. Urbanization, agricultural and industrial development have led to increased nitrogen (N) and phosphorus (P) discharge, which affect CHAB potentials of receiving waters. The amounts, proportions and chemical composition of N and P sources can influence the composition, magnitude and duration of blooms. This, in turn, has ramifications for food web dynamics (toxic or inedible CHABs), nutrient and oxygen cycling and nutrient budgets. Some CHABs are capable of N2 fixation, a process that can influence N availability and budgets. Certain invasive N2 fixing taxa (e.g., Cylindrospermopsis, Lyngbya) also effectively compete for fixed N during spring, N-enriched runoff periods, while they use N2 fixation to supplant their N needs during N-deplete summer months. Control of these taxa is strongly dependent on P supply. However, additional factors, such as molar N:P supply ratios, organic matter availability, light attenuation, freshwater discharge, flushing rates (residence time) and water column stability play interactive roles in determining CHAB composition (i.e. N2 fixing vs. non-N2 fixing taxa) and biomass. Bloom potentials of nutrient-impacted waters are sensitive to water residence (or flushing) time, temperatures (preference for > 15 degrees C), vertical mixing and turbidity. These physical forcing features can control absolute growth rates of bloom taxa. Human activities may affect "bottom up" physical-chemical modulators either directly, by controlling hydrologic, nutrient, sediment and toxic discharges, or indirectly, by influencing climate. Control and management of cyanobacterial and other phytoplankton blooms invariably includes nutrient input constraints, most often focused on N and/or P. While single nutrient input constraints may be effective in some water bodies, dual N and P input reductions are usually required for effective long-term control and management of blooms. In some systems where hydrologic manipulations (i.e., plentiful water supplies) are possible, reducing the water residence time by flushing and artificial mixing (along with nutrient input constraints) can be effective alternatives. Blooms that are not readily consumed and transferred up the food web will form a relatively large proportion of sedimented organic matter. This, in turn, will exacerbate sediment oxygen demand, and enhance the potential for oxygen depletion and release of nutrients back to the water column. This scenario is particularly problematic in long-residence time (i.e., months) systems, where blooms may exert a strong positive feedback on future events. Implications of these scenarios and the confounding issues of climatic (hydrologic) variability, including droughts, tropical storms, hurricanes and floods, will be discussed in the context of developing effective CHAB control strategies along the freshwater-marine continuum. PMID:18461771
A moored optical buoy was deployed in the Pearl River estuarine waters for a 15-day period. A four-day algal bloom event occurred during this study period. Both chlorophyll a concentration and algal cell density (a proxy for biomass) changed dramatically before and after the event. The chlorophyll concentration at a 2.3m depth rose from 5.15 mg/m(-3) at 15:00 h on August 19 to 23.62 mg/m(-3) at 9:00 h on August 21, and then decreased to 3.24 mg/m(-3) at 15:00 h on August 24. The corresponding cell density ranged from 1.57 x 10(5) to 1.76 x 10(6)cells/L. We used normalized fluorescence line height (NFLH) and normalized fluorescence intensity (NFI) in order to determine fluorescence activity. Combined with the in situ sampling dataset, we were able to correlate natural fluorescence (NFLH and NFI) with chlorophyll a concentrations, and found correlation coefficients of 0.72 and 0.75, respectively. We also found correlations between natural fluorescence and cell density, with correlation coefficients of 0.71 and 0.65, respectively. These results indicate that applying continuous time series of natural fluorescence can reflect changes in biomass. This technique will prove extremely useful for in situ and real-time observations using an optical buoy. Although there are still problems to solve in the real-time observation of natural fluorescence in algal bloom events, we discuss the primary factors affecting fluorescence signals and suggest possible methods for mitigating these issues. PMID:18649898
Zhao, Jun; Cao, Wenxi; Yang, Yuezhong; Wang, Guifen; Zhou, Wen; Sun, Zhaohua
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\\u000a Gulf coasts and the Atlantic coast to North Carolina. This dinoflagellate produces a suite of polyether neurotoxins, called\\u000a brevetoxins, that cause severe impacts to natural
R. H. Pierce; M. S. Henry
The Southern Bight of the North Sea is characterised by a large influence of river inputs, which results in eutrophication of the area. High concentrations of plankton biomass and suspended matter have been reported for this area, in relation with blooms of different species and resuspension of bottom sediments. In spring the haptophyte Phaeocystis globosa blooms throughout the area reaching up to 30 mg Chlorophyll m-3 or more nearshore. This event is followed in June by red tides of the dinoflagellate Noctiluca scintillans. These blooms are concurrent with different species of diatoms. The strong optical signature of these blooms is clear to human observers making them potentially detectable in satellite imagery. As a first step in this direction, sampling has been carried out in the area, during Phaeocystis and Noctiluca blooms in 2003 and 2004. Phytoplankton pigments and inherent optical properties (particle, detrital and phytoplankton absorption) have been measured spectrophotometrically, and in situ using an ac-9 for total absorption and particle scattering. Field data were compared with optical properties of pure species obtained in laboratory. In parallel, water-leaving reflectance has been also measured. In this paper we characterise the optical signatures of diatoms, Phaeocystis and Noctiluca and their contribution to total absorption. The impact on water-leaving reflectance spectra is evaluated; in order to assess the conditions in which remote sensing can provide information for monitoring the timing, extent and magnitude of blooms in this coastal area.
Astoreca, Rosa; Rousseau, Veronique; Ruddick, Kevin; Van Mol, Barbara; Parent, Jean-Yves; Lancelot, Christiane
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
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
ABSTRACT Blooms,of toxic ,algae are increasing in magnitude and frequency around the globe, causing extensive,economic ,and ,environmental ,damage. , Impacts of this ,phenomenon ,directly affect the aquaculture, tourism, and fishing industries, but scientist have only recently investigated the scope of indirect affects surrounding ,Harmful Algal Blooms (HABs). Although HABs occur naturally, the exponential increase in nutrients, heavy metals, and dissolved
Ian C Robbins; Jeff Sevadjian
Feeding strategies of copepods were studied during a dinoflagellate-dominated bloom in the North Sea in August 2001. The aim of this study was to evaluate the importance of mesozooplankton grazing as a biological loss factor of harmful algal blooms under natural conditions. Therefore, ingestion, egestion and egg production experiments were performed with the most abundant copepod species Calanus helgolandicus, Temora
Sandra Jansen; Christian Wexels Riser; Paul Wassmann; Ulrich Bathmann
Anthropogenically-derived increases in atmospheric greenhouse gas concentrations have been implicated in recent climate change, and are projected to substantially impact the climate on a global scale in the future. For marine and freshwater systems, increasing concentrations of greenhouse gases are expected to increase surface temperatures, lower pH, and cause changes to vertical mixing, upwelling, precipitation, and evaporation patterns. The potential
Stephanie K Moore; Vera L Trainer; Nathan J Mantua; Micaela S Parker; Edward A Laws; Lorraine C Backer; Lora E Fleming
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 ...
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
The immediate early gene c-fos, and its protein product c-Fos, are known to be induced in neurons of mammals and fish as a result of neuronal stimulation. The purpose of this study was to quantitatively examine CNS alterations in killifish, Fundulus heter...
J. D. Salierno N. S. Snyder A. Z. Murphy M. Poli S. Hall
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
Michael J. Twiner; Spencer Fire; Lori Schwacke; Leigh Davidson; Zhihong Wang; Steve Morton; Stephen Roth; Brian Balmer; Teresa K. Rowles; Randall S. Wells; Richard Unsworth
. We examined,the Aquatic Sciences and Fisheries Abstracts world database of FAO, Rome to which the National Institute of Oceanography,Goa provides inputs for the whole of India. This database holds research publication details on aspects regarding marine, brackish water and freshwater,. Patchy and scattered efforts on bloom research in Indian waters were discernible. Most of the investigations seemed only to
S. R. Bhat; S. G. Prabhu Matondkar
Extreme population fluctuations, or outbreaks, are driven by interacting processes that are often more complex than isolated\\u000a changes in consumer or resource control. Blooms of the macroalga Caulerpa sertularioides in the eastern tropical Pacific overgrew and killed reef-building corals, with blooms onto reefs corresponding to cool La\\u000a Niña phases of inter-decadal fluctuations of the El Niño–Southern Oscillation. We quantified factors
Tyler B. Smith; Peggy Fong; Rachel Kennison; Jayson Smith
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]|[Free Univ. of Brussels (Belgium). Dept. of Oceanography; Steefel, C.I. [Lawrence Livermore National Lab., CA (United States). Geosciences and Environmental Technologies Div.
In 1975, the 107 acre Morses Pond in Wellesley, Massachusetts was treated with potassium permanganate for removal of iron and oxidation of colored organic complexes that reduce visibility and stimulate algal growth. The goal of this field test was to redu...
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
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
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
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
Pyrolysis experiments were performed with algal and lignocellulosic feedstocks under similar reactor conditions for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C\\/O and H\\/C molar ratio as well as calorific values, were found to be similar
Balakrishna Maddi; Sridhar Viamajala; Sasidhar Varanasi
Aureococcus anophagefferens, a harmful bloom-forming alga responsible for brown tides in estuaries of the Middle Atlantic U.S., has been investigated by atomic force microscopy for the first time, using probes functionalized with a monoclonal antibody specific for the alga. The rupture force between a single monoclonal antibody and the surface of A. anophagefferens was experimentally found to be 246 +/- 11 pN at the load rate of 12 nN/s. Force histograms for A. anophagefferens and other similarly-sized algae are presented and analyzed. The results illustrate the effects of load rates, and demonstrate that force-distance measurements can be used to build biosensors with high signal-to-noise ratios for A. anophagefferens. The methods described in this paper can be used, in principle, to construct sensors with single-cell resolution for arbitrary cells for which monoclonal antibodies are available. PMID:16999239
Lee, Alexander S; Mahapatro, Mrinal; Caron, David A; Requicha, Aristides A G; Stauffer, Beth A; Thompson, Mark E; Zhou, Chongwu
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
Water samples were collected during a red tide event in November 2001, near San Lucas Island (Gulf of Nicoya, Costa Rica). Superficial temperature was 27 degrees C and water was turbid, with no fetid smell. One sample was treated with negative staining and observed using a transmission electron microscope (TEM); another sample was observed using a scanning electron microscope (SEM). Samples had high concentrations of the diatom Pseudo-Nitzschia pungensf pungens (characterized by two rows of poroids in the external channel), and lower concentrations of Skeletonema costatum (chains joined by external microtubules) and Chaetoceros lorenzianus (oval apertures and long chains, having setae with distinctive transverse rows and spines). This is the first time that the first species was described producing red tides in Costa Rica. However, reports about red tides with high concentration of species like P. pungens (variety multiseries) are increasing. These species have been related to the production of domoic acid, a low molecular weight amino acid which in humans can cause amnesic intoxications with seafood. Previously, Costa Rican reports of toxic accidents only referred to seafood contaminated with Pyrodinium bahamense var. compressum and Gymnodinium catenatum dinoflagellates. The increase in the number of Pseudo-Nitzschia causing harmful algae blooms is of interest for scientists around the world and must be documented. Similarly, some Chaetoceros species have been reported to be harmful to fish. We strongly recommend the establishment of a permanent surveillance program monitoring the presence of these species new at Costa Rican Pacific coast. Since the amnesic toxin is soluble in water and heat-resistant, we want to stress the possibility of having human cases of amnesic intoxication. PMID:17465126
Vargas-Montero, Maribelle; Freer, Enrique
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
David U. Hernández-Becerril; Rosalba Alonso-RodrÍguez; Cynthia Álvarez-Góngora; Sofia A. Barón-Campis; Gerardo Ceballos-Corona; Jorge Herrera-Silveira; MarÍa E. Meave del Castillo; Norma Juárez-RuÍz; Fanny Merino-Virgilio; Alejandro Morales-Blake; José L. Ochoa; Elizabeth Orellana-Cepeda; Casimiro RamÍrez-Camarena; Raciel RodrÍguez-Salvador
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.
A web-based distributed system for monitoring and forecasting of the marine environment has been developed in line with INfrastructure for SPatial InfoRmation in Europe (INSPIRE) and Global Monitoring for Environment and Security (GMES) recommendations for a European Spatial Data Infrastructure (SDI). This system, called DISPRO, enables integration and distribution of multi-source data from satellites, aircraft, and in situ instruments, as
Éamonn Ó Tuama; Torill Hamre
In the rapidly urbanizing coastal zone of South Carolina, intensive landscape maintenance and turf management are significant sources of nonpoint source pollutant loadings. The best management practice of choice for stormwater in this region is wet detention ponds, the majority of which are brackish lagoons. Typically, stormwater is piped directly into the ponds, but ponds have limited capacity for processing
Alan J. Lewitus; Larissa M. Brock; Marianne K. Burke; Krista A. DeMattio; Susan B. Wilde
The ability to detect harmful algal bloom (HAB) species and their toxins in real- or near real-time is a critical need for researchers studying HAB\\/toxin dynamics, as well as for coastal resource managers charged with monitoring bloom populations in order to mitigate their wide ranging impacts. The Environmental Sample Processor (ESP), a robotic electromechanical\\/fluidic system, was developed for the autonomous,
Gregory J. Doucette; Christina M. Mikulski; Kelly L. Jones; Kristen L. King; Dianne I. Greenfield; Roman Marin III; Scott Jensen; Brent Roman; Christopher T. Elliott; Christopher A. Scholin
Clays are useful in environmental water cleaning because they cause flocculation of the contaminated microorganisms. In order to develop an improved method of mitigating the deleterious effect of harmful algal blooms (HABs) in Lake Taihu, China, we prepared clays from the sediments of the lake and modified the clays with hexadecyl trimethyl ammonium bromide (CTAB). The capability of the modified
Guofeng Liu; Chengxin Fan; Jicheng Zhong; Lu Zhang; Shiming Ding; Shaohua Yan; Shiqun Han
During the first Southern Ocean Iron RElease Experiment (SOIREE), a suite of biogeochemical measurements (water column 234Th and ?13Corg inventories, particle fluxes from sediment traps, phytoplankton sinking rates) were undertaken to test the hypothesis that the vertical export of particulate organic carbon (POC) is enhanced due to iron-induced increases in phytoplankton production. During the 13-days that the SOIREE bloom was monitored, export fluxes within the iron-fertilised patch were not substantially different to those in waters outside the bloom. On days 11-13, iron enrichment may have caused particle transformations that could lead to elevated future export via particle aggregation and/or diatom chain formation. The unknown time-lag between increased production and export, the longevity of the SOIREE bloom, and the absence of nutrient limitation over days 1-13, however, prohibit prediction of any iron-induced export. This conclusion highlights the difficulties of fully testing the “Iron Hypothesis” and for evaluating the implications for global climate change.
Nodder, Scott D.; Charette, Matthew A.; Waite, Anya M.; Trull, Tom W.; Boyd, Philip W.; Zeldis, John; Buesseler, Ken O.
This paper describes the results of a harmful algal bloom (HAB) monitoring effort in the Indian River Lagoon. The goal of the study was to describe spatial and temporal variability in the distribution, frequency of occurrence, and composition of HABs, along with an examination of potential driving factors, such as hydrologic conditions and nutrient concentrations. Six sampling sites in the
Edward J. Phlips; Susan Badylak; Mary Christman; Jennifer Wolny; Julie Brame; Jay Garland; Lauren Hall; Jane Hart; Jan Landsberg; Margaret Lasi; Jean Lockwood; Richard Paperno; Doug Scheidt; Ariane Staples; Karen Steidinger
Toxic algal species of marine and brackish-water plankton, as well as nontoxic microalgae, which are capable of initiating harmful blooms, cause a detriment to human health (seafood poisoning) and often lead to a total crisis of coastal water ecosystems. The Russian coastal waters are inhabited by dozens of toxic and bloom-causing algal species, their toxins are accumulated in the tissues of edible mollusks, and there have been incidents of human poisonings and marine fauna mortality due to these blooms. An analysis of the current situation concerning the problem of toxic algae and harmful blooms of nontoxic species in the seas of Russia provides evidence that it is necessary to create a system of compulsory governmental monitoring of the exploited marine areas to serve as the basis of ecological safety control in the exploitation of the biological resources of the Russian Federation, as well to introduce compulsory sanitary control of diarrheic, paralytic, and amnesic phycotoxins. The compiled summary of algal toxic and potentially toxic species met in the European and Far Eastern seas of Russia is given with notes on their toxicity type and its manifestations.
Vershinin, A. O.; Orlova, T. Yu.
The biological interactions and the physical and chemical properties of the littoral zone of Lake Krugersdrift were studied 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 of the mcyB and mcyD genes of the mcy gene cluster that synthesizes microcystin. An increase in Microcystis toxicity at sites dominated by the cyanobacterial scum was accompanied by an increase in total abundance of the macroinvertebrate families Hirudinae, Chironomidae, and Tubificidae. Sites located away from the cyanobacterial scum had a lower abundance but a higher diversity of macroinvertebrates. The water quality under the Microcystis scum was characterized by low pH values, low concentrations of dissolved oxygen, and lower total alkalinity values. The periphytic alga Ulothrix zonata was absent in areas dominated by the cyanobacterial scum, possibly as a result of overshadowing by the scum or direct toxic allelopathic effects on growth and photosynthesis. The diatom Diatoma vulgare dominated the benthic algal flora beneath the cyanobacterial scum. PMID:18802748
Oberholster, Paul J; Botha, Anna-Maria; Ashton, Peter J
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.
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
A study of Santa Ponça Bay (Balearic Islands) was conducted during summer 2002 to understand further the processes controlling recurrent Alexandrium taylori blooms near the beach. These massive algal proliferations (106 cells L-1) have become common in many anthropized pocket beaches of the Mediterranean during the summer season. Nearshore dissolved inorganic nutrient concentrations (DIN) are generally high near the shoreline (avg. DIN at 1.6 ?M), yet this factor alone is insufficient to explain harmful algal bloom (HAB) occurrences at some beaches and their absence in others. It is postulated that summer conditions, and particularly, the mild breeze conditions are key factors into understanding these nearshore blooms. The advantages of this coastal environment for a migrating dinoflagellate such as A. taylori are discussed. Resilience to undergo enhanced turbulence episodes, motility, day/night migration and a favorable current regime that produces shoreward transport at sea surface are regarded as concurrent mechanisms that lead to HAB generation and maintenance.
Basterretxea, G.; Garces, E.; Jordi, A.; Maso, M.; Tintore, J.
Marine microalgae support world fisheries production and influence climate through various mechanisms. They are also responsible for harmful blooms that adversely impact coastal ecosystems and economies. Optimal growth and survival of many bloom-forming microalgae, including climatically important dinoflagellates and coccolithophores, requires the close association of specific bacterial species, but the reasons for these associations are unknown. Here, we report that several clades of Marinobacter ubiquitously found in close association with dinoflagellates and coccolithophores produce an unusual lower-affinity dicitrate siderophore, vibrioferrin (VF). Fe-VF chelates undergo photolysis at rates that are 10–20 times higher than siderophores produced by free-living marine bacteria, and unlike the latter, the VF photoproduct has no measurable affinity for iron. While both an algal-associated bacterium and a representative dinoflagellate partner, Scrippsiella trochoidea, used iron from Fe-VF chelates in the dark, in situ photolysis of the chelates in the presence of attenuated sunlight increased bacterial iron uptake by 70% and algal uptake by >20-fold. These results suggest that the bacteria promote algal assimilation of iron by facilitating photochemical redox cycling of this critical nutrient. Also, binary culture experiments and genomic evidence suggest that the algal cells release organic molecules that are used by the bacteria for growth. Such mutualistic sharing of iron and fixed carbon has important implications toward our understanding of the close beneficial interactions between marine bacteria and phytoplankton, and the effect of these interactions on algal blooms and climate.
Amin, Shady A.; Green, David H.; Hart, Mark C.; Kupper, Frithjof C.; Sunda, William G.; Carrano, Carl J.
Marine microalgae support world fisheries production and influence climate through various mechanisms. They are also responsible for harmful blooms that adversely impact coastal ecosystems and economies. Optimal growth and survival of many bloom-forming microalgae, including climatically important dinoflagellates and coccolithophores, requires the close association of specific bacterial species, but the reasons for these associations are unknown. Here, we report that several clades of Marinobacter ubiquitously found in close association with dinoflagellates and coccolithophores produce an unusual lower-affinity dicitrate siderophore, vibrioferrin (VF). Fe-VF chelates undergo photolysis at rates that are 10-20 times higher than siderophores produced by free-living marine bacteria, and unlike the latter, the VF photoproduct has no measurable affinity for iron. While both an algal-associated bacterium and a representative dinoflagellate partner, Scrippsiella trochoidea, used iron from Fe-VF chelates in the dark, in situ photolysis of the chelates in the presence of attenuated sunlight increased bacterial iron uptake by 70% and algal uptake by >20-fold. These results suggest that the bacteria promote algal assimilation of iron by facilitating photochemical redox cycling of this critical nutrient. Also, binary culture experiments and genomic evidence suggest that the algal cells release organic molecules that are used by the bacteria for growth. Such mutualistic sharing of iron and fixed carbon has important implications toward our understanding of the close beneficial interactions between marine bacteria and phytoplankton, and the effect of these interactions on algal blooms and climate. PMID:19805106
Amin, Shady A; Green, David H; Hart, Mark C; Küpper, Frithjof C; Sunda, William G; Carrano, Carl J
The formation of winter bloom (January–March) was studied in deep waters of the northeastern Arabian Sea (NAS) during 2003 and 2004. Six ship cruises were undertaken at different phases of the bloom to examine its formation. Along with physical and biological observations, optical parameters including profiles of upwelling and downwelling irradiance were collected using a Satlantic underwater radiometer and photosynthetically
R. M. Dwivedi; M. Raman; K. N. Babu; S. K. Singh; N. K. Vyas; S. G. P. Matondkar
The toxicity of seven major HAB (harmful algal bloom) species\\/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and
Tian Yan; Yunfeng Wang; Liping Wang; Yang Chen; Gang Han; Mingjiang Zhou
A comparative study was made to determine the effect of water turbidity on algal growth. The growth of algae in Illinois River water which is characterized by turbid conditions and generally void of algal blooms was compared with algal growth in Fox River...
W. C. Wang
The detection and prevention of cyanobacterial blooms are important issues in water quality management. As such, the diversity and community dynamics of cyanobacteria during cyanobacterial bloom in the Daechung Reservoir, Korea, were studied by analyzing the intergenic spacer (IGS) region between phycocyanin subunit genes cpcB and cpcA (cpcBA IGS). To amplify the cpcBA IGS from environmental samples, new PCR primers that could cover a wider range of cyanobacteria than previously known primers were designed. In the samples taken around the bloom peak (2 September 2003), seven groups of cpcBA IGS sequences were detected, and none of the amplified cpcBA IGSs was closely related to the cpcBA IGS from chloroplasts. Apart from the Microcystis-, Aphanizomenon (Anabaena)-, Pseudanabaena-, and Planktothrix (Oscillatoria)-like groups, the three other groups of cpcBA IGS sequences were only distantly related to previously reported sequences (<85% similarity to their closest relatives). The most prominent changes during the bloom were the gradual decrease and eventual disappearance of the Aphanizomenon (Anabaena)-like group before the bloom peak and the gradual increase and sudden disappearance of Planktothrix (Oscillatoria)-like groups right after the bloom peak. The community succession profile obtained based on the cpcBA IGS analysis was also supported by a PCR-denaturing gradient gel electrophoresis analysis of the 16S rRNA genes.
Kim, Song-Gun; Rhee, Sung-Keun; Ahn, Chi-Yong; Ko, So-Ra; Choi, Gang-Guk; Bae, Jin-Woo; Park, Yong-Ha; Oh, Hee-Mock
Tissue levels of mercury (Hg; total, organic) and selenium (Se) were assessed in juvenile lemon sharks (Negaprion brevirostris) from Florida nearshore waters collected during a harmful algal bloom (HAB, brevetoxin) event and compared with sharks not\\u000a exposed to HABs. In all sharks studied, total Hg levels in the muscle were generally present in a molar excess over Se (which\\u000a may
Dong-Ha Nam; Douglas H. Adams; Eric A. Reyier; Niladri Basu
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
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. PMID:22069623
Ignatiades, Lydia; Gotsis-Skretas, Olympia
Inorganic nutrients and organic nitrogen were measured in April June of 1998 and 2000 near Casco Bay, Maine and the adjacent coastal waters as part of the Ecology and Oceanography of Harmful Algal Blooms—Gulf of Maine (ECOHAB-GOM) program. The samples were collected during development of toxic Alexandrium fundyense blooms [Keafer, B.A., Churchill, J.H., Anderson, D.M., 2005. Blooms of the toxic dinoflagellate, Alexandrium fundyense in the Casco Bay region of the western Gulf of Maine: advection from offshore source populations and interactions with the Kennebec River plume. Deep Sea Research II, this issue [doi:10.1016/j.dsr2.2005.06.017
Love, Rebecca C.; Loder, Theodore C.; Keafer, Bruce A.
Inorganic nutrients and organic nitrogen were measured in April-June of 1998 and 2000 near Casco Bay, Maine and the adjacent coastal waters as part of the Ecology and Oceanography of Harmful Algal Blooms—Gulf of Maine (ECOHAB-GOM) program. The samples were collected during development of toxic Alexandrium fundyense blooms [ Keafer, B.A., Churchill, J.H., Anderson, D.M., 2005. Blooms of the toxic dinoflagellate, Alexandrium fundyense in the Casco Bay region of the western Gulf of Maine: advection from offshore source populations and interactions with the Kennebec River plume. Deep Sea Research II, this issue [ doi:10.1016/j.dsr2.2005.06.017
Love, Rebecca C.; Loder, Theodore C.; Keafer, Bruce A.
An apparent link between upwelling-related physical signatures, macronutrients, and toxic diatom blooms in the various “hotspots” throughout California has motivated attempts to forecast harmful algal blooms (HABs) as a function of select environmental variables. Empirical models for predicting toxic Pseudo-nitzschia blooms in one such region, the Santa Barbara Channel (SBC), are tested in a nowcast mode using predictions based on merging data from MODIS ocean color geophysical products and the Regional Ocean Modeling System (ROMS) applied to the Southern California Bight. Thresholds for each model generate event forecasts. Spatially-explicit, monthly HAB maps are compared to shipboard observations and California monitoring data, demonstrating that the models predict offshore events otherwise undetected by nearshore monitoring. The use of mechanistic hydrodynamic models in concert with empirical, biological models facilitates future process studies on the effects of coastal eutrophication and climate change on regional HAB dynamics.
Anderson, Clarissa R.; Kudela, Raphael M.; Benitez-Nelson, Claudia; Sekula-Wood, Emily; Burrell, Christopher T.; Chao, Yi; Langlois, Gregg; Goodman, Jo; Siegel, David A.
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.
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.
Grigoriev, Igor; Gobler, Christopher; Salamov, Asaf; Kuo, Alan; Terry, Astrid; Pangillian, Jasmyn; Lindquist, Erika; Lucas, Susan; Berry, Dianna; Dyhrman, Sonya; Wilhelm, Steven; Lobanov, Alexei; Zhang, Yan; Collier, Jackie; Wurch, Louie; Kusta, Adam; Dill, Brian; Shsh, Manesh; VerBerkmoes, Nathan; Paulsen, Ian; Hattenrath-Lehmann, Theresa; Talmage, Stephanie; Walker, Elyse; Koch, Florian; Burson, Amanda; Marcoval, Maria; Tang, Yin-Zhong; LeCleir, Gary; Coyne, Kathyrn; Berg, Gry; Bertrand, Erin; Saito, Mak; Gladyshev, Vadim
The physiological impact of short and long-term shifts from low to high light intensity (30–600?molphotonsm?2s?1) was assessed for the harmful blooming raphidophyte, Chattonella subsalsa and dinoflagellate, Prorocentrum minimum, isolated from the inland bays of Delaware. Analysis of photochemical activity by active chlorophyll fluorescence indicated a significant decline in the photochemical capacity of photosystem II (PSII), Fv\\/Fm, in both algal species
Mark E. Warner; Matilda L. Madden
Virus and virus-like particles (VLP) have been observed in all major algal classes. Few host-virus systems of microalgae have until now been brought into culture and extensively studied. For Emiliania huxleyi we have been able to describe viral infection during blooms in mesocosms and in landlocked fjords. Evidence of viral lysis of E. huxleyi during blooms in the North Sea
Gunnar Bratbak; William Wilson; Mikal Heldal
The trace element selenium (Se) is required for the biosynthesis of selenocysteine (Sec), the 21st amino acid in the genetic code, but its role in the ecology of harmful algal blooms (HABs) is unknown. Here, we examined the role of Se in the biology and ecology of the harmful pelagophyte, Aureococcus anophagefferens, through cell culture, genomic analyses, and ecosystem studies. This organism has the largest and the most diverse selenoproteome identified to date that consists of at least 59 selenoproteins, including known eukaryotic selenoproteins, selenoproteins previously only detected in bacteria, and novel selenoproteins. The A. anophagefferens selenoproteome was dominated by the thioredoxin fold proteins and oxidoreductase functions were assigned to the majority of detected selenoproteins. Insertion of Sec in these proteins was supported by a unique Sec insertion sequence. Se was required for the growth of A. anophagefferens as cultures grew maximally at nanomolar Se concentrations. In a coastal ecosystem, dissolved Se concentrations were elevated before and after A. anophagefferens blooms, but were reduced by >95% during the peak of blooms to 0.05?nM. Consistent with this pattern, enrichment of seawater with selenite before and after a bloom did not affect the growth of A. anophagefferens, but enrichment during the peak of the bloom significantly increased population growth rates. These findings demonstrate that Se inventories, which can be anthropogenically enriched, can support proliferation of HABs, such as A. anophagefferens through its synthesis of a large arsenal of Se-dependent oxidoreductases that fine-tune cellular redox homeostasis. PMID:23466703
Gobler, Christopher J; Lobanov, Alexei V; Tang, Ying-Zhong; Turanov, Anton A; Zhang, Yan; Doblin, Martina; Taylor, Gordon T; Sañudo-Wilhelmy, Sergio A; Grigoriev, Igor V; Gladyshev, Vadim N
Reductions in allochthonous nutrient loading to lakes from point and nonpoint sources are intended to improve lake water quality. Yet many lakes continue to experience algal blooms and lake anoxia after these sources are reduced or discontinued. Algal-available nutrients from autochthonous sources are likely to influence lake productivity in these systems. This research seeks to quantify changes in algal biomass
E. L. Ceballos; T. C. Rasmussen
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
Sound field methodologies are an essential prerequisite in the development of a basic understanding of toxic cyanobacteria blooms. Sample collection, on-site processing, storage and transportation, and subsequent analysis and documentation are all critically dependent on a sound field program that allows the researcher to construct, with minimal uncertainty, linkages between bloom events and cyanotoxin production with the ecology of the studied system. Since 1999, we have collected samples in Lake Erie as part of the MELEE (Microbial Ecology of the Lake Erie Ecosystem) and MERHAB-LGL (Monitoring Event Responses for Harmful Algal Blooms in the Lower Great Lakes) research programs to develop appropriate tools and refine methods necessary to characterize the ecology of the reoccurring cyanobacterial blooms in the systems. Satellite imagery, large ship expeditions, classical and novel molecular tools have been combined to provide insight into both the cyanobacteria responsible for these events as well as into some of the environmental cues that may facilitate the formation of toxic blooms. This information, as well new directions in cyano-specific monitoring will be presented to highlight needs for field program monitoring and/or researching toxic freshwater cyanobacteria. PMID:18461781
Wilhelm, Steven W
Nitrogen loading to the Bassin d'Arcachon coastal lagoon (SW France) was evaluated by studying land-use and nitrogen output in its 3001 km2 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.
The existence of algal blooms of cyanobacteria has been documented in Lake Erie which is biologically the most active lake among the Great Lakes of North America. Cyanobacteria are known to produce toxic substances that are detrimental to the lake's biodiversity. The early detection of harmful algal blooms in the Western Basin of Lake Erie (WBLE) requires a more efficient and accurate monitoring tool. Remote sensing is an efficient tool with high spatial and temporal coverage that can allow accurate and timely detection of cyanobacteria bloom. However, in optically complex environments, such as in the Western Basin of Lake Erie, the water contains multiple constituents including phytoplankton, suspended sediment, and dissolved organic carbon and the discrimination between the various constituents requires separation of the mostly overlapping scattering and absorption properties. Determining a single in-water constituent from satellite observations is complicated when working with mixed spectral signatures. This study focuses on improving the quantification of chlorophyll a and phycocyanin as proxies to detect cyanobacteria remotely, by applying signal decomposition to the reflectance data using spectra transformation. This study indicates that applying spectral transformation using wavelet analysis, results in increased accuracy as compared to using other feature extraction methods such as the principle component analysis of untransformed spectra and conventional spectral indices. The superior results of the wavelet technique in discriminating between the various water constituents and detecting cyanobacteria can be attributed to the frequency content retrieved by the wavelet technique combined with the localization property of wavelets.
Al, A.; Witter, D. L.; Ortiz, J. D.
A pilot project has been carried out to demonstrate the applicability of remote sensing in the Xth region of Chile, related to the monitoring of algal blooms. Most of the fish farms of the country are located in this area, where considerable economic losses for this activity are the consequence of algal blooms. The implementation of new technologies to monitor
C. Rodríguez-Benito; C. Haag; A. Alvial
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
Ice-associated phytoplankton blooms in the southeastern Bering Sea can critically impact the food web structure, from lower tropic level production to marine fisheries. By coupling pelagic and sea ice algal components, our 1-D ecosystem model successfully reproduced the observed ice-associated blooms in 1997 and 1999 at the NOAA\\/PMEL mooring M2. The model results suggest that the ice-associated blooms were seeded
Meibing Jin; Clara Deal; Jia Wang; Vera Alexander; Rolf Gradinger; Sei-ichi Saitoh; Takahiro Iida; Zhenwen Wan; Phyllis Stabeno
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
D. G. Redalje; S. E. Lohrenz; M. J. Natter; M. D. Tuel; G. J. Kirkpatrick; D. F. Millie; G. L. Fahnenstiel; F. M. Van Dolah
Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA), the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs) of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX) produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA). Over a ten-year study period (2000-2009) we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009) with 36% of all animals testing positive for brevetoxin (n?=?118) and 53% positive for DA (n?=?83) with several individuals (14%) testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p?=?0.001) and eosinophil (p<0.001) counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health. PMID:21423740
Twiner, Michael J; Fire, Spencer; Schwacke, Lori; Davidson, Leigh; Wang, Zhihong; Morton, Steve; Roth, Stephen; Balmer, Brian; Rowles, Teresa K; Wells, Randall S
A comparative study was conducted with representatives of four ecologically important freshwater algal phyla (Chlorophyta,\\u000a Cyanophyta, Bacillariophyta and Pyrrophyta) in order to (1) analyze the relationship between reflectance spectral features\\u000a and algal density, and (2) to elucidate and characterize possible diagnostic spectral reflectance features for identification\\u000a of dominant groups in algal bloom states. Algae (two chlorophytes, a cyanophyte and a
Anatoly A. Gitelson; John F. Schalles; Donald C. Rundquist; Frank R. Schiebe; Yosef Z. Yacobi
Seawater desalination by reverse osmosis (RO) is a reliable method for augmenting drinking water supplies. In recent years, the number and size of these water projects have increased dramatically. As freshwater resources become limited due to global climate change, rising demand, and exhausted local water supplies, seawater desalination will play an important role in the world's future water supply, reaching far beyond its deep roots in the Middle East. Emerging contaminants have been widely discussed with respect to wastewater and freshwater sources, but also must be considered for seawater desalination facilities to ensure the long-term safety and suitability of this emerging water supply. Harmful algal blooms, frequently referred to as 'red tides' due to their vibrant colors, are a concern for desalination plants due to the high biomass of microalgae present in ocean waters during these events, and a variety of substances that some of these algae produce. These compounds range from noxious substances to powerful neurotoxins that constitute significant public health risks if they are not effectively and completely removed by the RO membranes. Algal blooms can cause significant operational issues that result in increased chemical consumption, increased membrane fouling rates, and in extreme cases, a plant to be taken off-line. Early algal bloom detection by desalination facilities is essential so that operational adjustments can be made to ensure that production capacity remains unaffected. This review identifies the toxic substances, their known producers, and our present state of knowledge regarding the causes of toxic episodes, with a special focus on the Southern California Bight. PMID:19664796
Caron, David A; Garneau, Marie-Eve; Seubert, Erica; Howard, Meredith D A; Darjany, Lindsay; Schnetzer, Astrid; Cetini?, Ivona; Filteau, Gerry; Lauri, Phil; Jones, Burton; Trussell, Shane
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
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.; Do Chi, Thang; Mouillot, David
In this lesson, 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.
The goal of this study was to examine the significance of allelopathy by the raphidophyte Heterosigma akashiwo in a multispecies phytoplankton community in the field. Towards this aim, we sought allelochemicals of H. akashiwo, which had allelopathic effect both in laboratory experiments and in the field. As an initial step, we showed that the allelopathic effects of H. akashiwo filtrate were both species-specific and dependent upon the cell density of the target species. Secondly, we found for the first time that extracellular, high-molecular weight allelochemicals [that is, polysaccharide-protein complexes (APPCs)] were produced by a marine phytoplankton species, H. akashiwo. Thirdly, we indicated that the purified APPCs selectively inhibited the growth of the diatom Skeletonema costatum that is a major competitor of H. akashiwo, and thereby tended to promote the formation of monospecific H. akashiwo blooms. Furthermore, we demonstrated that the inhibitory effect of APPCs on the growth of the diatoms was determined by binding to the cell surface of the target species. Finally, we succeeded in the detection of APPCs in the field samples at concentrations exceeding their experimentally determined action threshold during the H. akashiwo bloom. Strategies for ecosystem control, including mitigation of harmful algal blooms (HABs), should take into account that red-tide organisms like H. akashiwo are already part of complex webs involving inter-specific allelopathic inhibition and ecosystem control during their dense blooms. PMID:19322242
Yamasaki, Yasuhiro; Shikata, Tomoyuki; Nukata, Atsushi; Ichiki, Satoko; Nagasoe, Sou; Matsubara, Tadashi; Shimasaki, Yohei; Nakao, Miki; Yamaguchi, Kenichi; Oshima, Yuji; Oda, Tatsuya; Ito, Makoto; Jenkinson, Ian R; Asakawa, Makio; Honjo, Tsuneo
Moral disagreements often revolve around the issue of harm to others. Identifying harms, however, is a contested enterprise. This paper provides a conceptual toolbox for identifying harms, and so possible wrongdoing, by drawing several distinctions. First, I distinguish between four modes of human vulnerability, forming four ways in which one can be in a harmed state. Second, I argue for the intrinsic disvalue of harm and so distinguish the presence of harm from the fact that it is instrumental to or constitutive of a valued act, practice or way of life. Finally, I distinguish between harm and wrongdoing, arguing that while harm is a normative concept requiring justification, not all harmed states are automatically unjustified. The advantage of this view is that it refocuses the moral debate on the normative issues involved while establishing a common basis to which both sides can agree: the presence of harm to others. PMID:21434956
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
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
Multiple interacting physical, chemical, and biotic factors, in proper combination, lead to the development and persistence of nuisance algal blooms. Upon examining combinations of envi- ronmental conditions most likely to elicit nuisance blooms, commonalities and analog situations become more apparent among coastal marine (dinoflagellate-dominated), estuarine (dinoflagellate- and cyanobacteria-dominated), and freshwater (cyanobacteria-dominated) ecosystems. A combi- nation of the following hydrological, chemical,
Hans W. Paerl
A bacterial strain named AB-4 showing algicidal activity against Chattonella marina was isolated from coastal water of ULjin, Republic of Korea. The isolated strain was identified as Bacillus sp. by culture morphology, biochemical reactions, and homology research based on 16S rDNA. The bacterial culture led to the lysis of algal cells, suggesting that the isolated strain produced a latent algal-lytic compound. Amongst changes in algicidal activity by different culture filtrate volumes, the 10% (100 microl/ml) concentration showed the biggest change in algicidal activity; there, estimated algicidal activity was 95%. The swimming movements of Chattonella marina cells were inhibited because of treatment of the bacterial culture; subsequently, Chattonella marina cells became swollen and rounded. With longer exposure time, algal cells were disrupted and cellular components lost their integrity and decomposed. The released algicide(s) were heat-tolerant and stable in pH variations, except pH 3, 4, and 5. Culture filtrate of Bacillus sp. AB-4 was toxic against harmful algae bloom (HAB) species and nontoxic against livefood organisms. Bacillus sp. AB-4 showed comparatively strong activity against Akashiwo sanguinea, Fibriocapsa japonica, Heterosigma akashiwo, and Scrippsiella trochoidea. These results suggest that the algicidal activity of Bacillus sp. AB-4 is potentially useful for controlling outbreaks of Chattonella marina. PMID:19229486
Kim, Yun Sook; Lee, Dae-Sung; Jeong, Seong-Yun; Lee, Woe Jae; Lee, Myung-Suk
The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.
Yan, Tian; Wang, Yunfeng; Wang, Liping; Chen, Yang; Han, Gang; Zhou, Mingjiang
Absorption rate coefficient of algae omega(i) to nutrients such as N and P could be used for describing algal increases/decreases velocity in water areas in theory. omega(i) raise might correspond to algal quickly growth and to ccelerate absorption of N and P while omega(i) decrease might correspond to algal decompose and release of N and P. According to locale measuring data along the Three-Gorges valley and algal dynamics model of nutritious absorption we have obtained some interest 3-dimension figures in which omega(i) will varies up and down obviously with N and P concentration in special bound to show a synergistic effects of N and P that might reveal an inner behavior of algal bloom/decompose. The research results explain in reason: (1) algal blooms do will happen in one special P/N range in a certain water system; (2) when omega(1) and omega(2) ascend rapidly and simultaneously in positive direction at same time algae would bloom, and when omega(1) and omega(2) descend sharply and simultaneously in negative direction at same time algae would decompose; (3) The velocity of algal bloom is not only same approximately as one of algal decompose, but also its variety has evidently periodic fluctuation. All of these could reveal effectively mechanism of nutritious absorption/release as algal bloom/decompose. PMID:17111610
Liu, Xin-An; Zhan, Min; Luo, Yan-Feng; Guo, Sheng-Wen
Abundance, production and extracellular enzymatic activity of free-living and attached bacteria were measured during the development and collapse of a spring bloom in a eutrophic lake. Free-living bacteria accounted for most of the total bacterial production during the first part of the bloom. Their production had a significant positive correlation to chlorophyll (P P P < .05), suggesting that algal
M. Middelboe; M. Søndergaard; Y. Letarte; N. H. Borch
In a seasonal environment, the timing of reproduction is usually scheduled to maximize the survival of offspring. Within deep water bodies, the phytoplankton spring bloom provides a short time window of high food quantity and quality for herbivores. The onset of algal bloom development, however, varies strongly from year to year due to interannual variability in meteorological conditions. Furthermore, the
HANNO S EEBENS; U LRICH
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
The algal spring bloom in the Baltic Sea represents an anomaly from the winter-spring bloom patterns worldwide in terms of frequent and recurring dominance of dinoflagellates over diatoms. Analysis of approximately 3500 spring bloom samples from the Baltic Sea monitoring programs revealed (i) that within the major basins the proportion of dinoflagellates varied from 0.1 (Kattegat) to >0.8 (central Baltic
Riina Klais; Timo Tamminen; Anke Kremp; Kristian Spilling; Kalle Olli; Dirk Steinke
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
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
Phytoplankton populations in the Tualatin River in northwestern Oregon are an important component of the dissolved oxygen (DO) budget of the river and are critical for maintaining DO levels in summer. During the low-flow summer period, sufficient nutrients and a long residence time typically combine with ample sunshine and warm water to fuel blooms of cryptophyte algae, diatoms, green and blue-green algae in the low-gradient, slow-moving reservoir reach of the lower river. Algae in the Tualatin River generally drift with the water rather than attach to the river bottom as a result of moderate water depths, slightly elevated turbidity caused by suspended colloidal material, and dominance of silty substrates. Growth of algae occurs as if on a “conveyor belt” of streamflow, a dynamic system that is continually refreshed with inflowing water. Transit through the system can take as long as 2 weeks during the summer low-flow period. Photosynthetic production of DO during algal blooms is important in offsetting oxygen consumption at the sediment-water interface caused by the decomposition of organic matter from primarily terrestrial sources, and the absence of photosynthesis can lead to low DO concentrations that can harm aquatic life. The periods with the lowest DO concentrations in recent years (since 2003) typically occur in August following a decline in algal abundance and activity, when DO concentrations often decrease to less than State standards for extended periods (nearly 80 days). Since 2003, algal populations have tended to be smaller and algal blooms have terminated earlier compared to conditions in the 1990s, leading to more frequent declines in DO to levels that do not meet State standards. This study was developed to document the current abundance and species composition of phytoplankton in the Tualatin River, identify the possible causes of the general decline in algae, and evaluate hypotheses to explain why algal blooms diminish in midsummer. Plankton and water-quality sample data from 2006 to 2008 were combined with parts of a larger discrete-sample and continuous water-quality monitoring dataset and examined to identify patterns in water-quality and algal conditions since 1991, with a particular emphasis on 2003–08. Longitudinal plankton surveys were conducted in 2006–08 at six sites between river miles (RM) 24.5 and 3.4 at 2- to 3-week intervals, or 5–6 per season, and in-situ bioassay experiments were conducted in 2008 to examine the potential effects of wastewater treatment facility (WWTF) effluent and phosphorus additions on phytoplankton biomass and algal photosynthesis. Phytoplankton and zooplankton community composition, streamflow, and water-quality data were analyzed using multivariate statistical techniques to gain insights into plankton dynamics to determine what factors might be most tied to the abundance and characteristics of the phytoplankton assemblages, and identify possible causes of their declines. The connection between low-DO events and algal declines was clearly evident, as bloom crashes were nearly always followed by periods of low DO. Algal blooms occurred each year during 2006–08, producing maximum chlorophyll-a (Chl-a) values in June or July generally in the range of 50–80 micrograms per liter (µg/L). Bloom crashes and absence of sufficient algal photosynthesis in mid- to late-summer contributed to minimum DO concentrations that were less than the State standard of 6.5 milligrams per liter (mg/L) based on the 30-day mean daily concentration, for 62–74 days each year. At times, the absolute minimum State standard (4 mg/L DO) also was not met. To learn more about why low-DO events occurred, specific algal declines during 2003–08 were scrutinized to determine their likely causal factors. From this information, a series of hypotheses were formulated and evaluated in terms of their ability to explain recent declines in algal populations in the river in late summer. Meteorological, streamflow, turbidity, water temperature, and conductance conditions in the Tualatin River
Carpenter, Kurt D.; Rounds, Stewart A.
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
Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of
Jiarong Hong; Siddharth Talapatra; Joseph Katz; Patricia A. Tester; Rebecca J. Waggett
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.
Microcystis aeruginosa is a species of freshwater cyanobacteria which can form harmful algal blooms in freshwater water bodies worldwide. However, in spite its sporadic occurrences for short periods of time in estuarine waters, their influence on zooplankton populations present in these ecosystems has not been extensively studied. In this work, Artemia franciscana was used as test organism model, studying mortality against several strains of M. aeruginosa with different degrees of toxigenicity, measuring whole-live cells and homogenate extracts. Results were compared with microcystin-LR equivalent content, measured by immunoassay. The results show that there were no significant differences between both exposure models (whole cells and extracts), and there are significant differences respect to the toxigenicity of cyanobacterial blooms depending of the M. aerugionosa strain involved in the process. Analysis of microcystin-LR equivalent concentration test immediately below the lowest significant concentration in all M. aerugionosa strains was used to determine the potential risk associated with the cell densities during a bloom. Comparison among the selected M. aerugionsa strains show that these factors have influence in the results obtained, and thus, several differences have been evidenced depending of the microcystin-LR equivalent production and the strain type involved. PMID:23246722
D'ors, A; Bartolomé, M C; Sánchez-Fortún, S
The world is facing energy crisis and environmental issues due to the depletion of fossil fuels and increasing CO2 concentration in the atmosphere. Growing microalgae can contribute to practical solutions for these global problems because they can harvest solar energy and capture CO2 by converting it into biofuel using photosynthesis. Microalgae are robust organisms capable of rapid growth under a variety of conditions including in open ponds or closed photobioreactors. Their reduced biomass compounds can be used as the feedstock for mass production of a variety of biofuels. As another advantage, their ability to accumulate or secrete biofuels can be controlled by changing their growth conditions or metabolic engineering. This review is aimed to highlight different forms of biofuels produced by microalgae and the approaches taken to improve their biofuel productivity. The costs for industrial-scale production of algal biofuels in open ponds or closed photobioreactors are analyzed. Different strategies for photoproduction of hydrogen by the hydrogenase enzyme of green algae are discussed. Algae are also good sources of biodiesel since some species can make large quantities of lipids as their biomass. The lipid contents for some of the best oil-producing strains of algae in optimized growth conditions are reviewed. The potential of microalgae for producing petroleum related chemicals or ready-make fuels such as bioethanol, triterpenic hydrocarbons, isobutyraldehyde, isobutanol, and isoprene from their biomass are also presented. PMID:23605290
Weak-anion exchange chromatography was used to explore the temporal variability in the speciation of dissolved P in the surface layer of a eutrophic reservoir. Authentic free ortho-P ion was the most common form of P on three of the five sampling occasions-including during a bloom of the green algae Botryococcus braunii indicating that the bloom was not P limited. Conversely, the absence of authentic ortho-P during a bloom of the dinoflagellate Ceratium hirundinella suggested the bloom was either P limited or co-limited. These observations were confirmed by algal-growth bioassay experiments. PMID:14568044
Baldwin, D S; Whittington, J; Oliver, R
Eutrophication in Lake Taihu - China's third largest freshwater lake - has led to deterioration of water quality and caused more frequent cyanobacteria blooms at many lake locations in recent years. Eutrophication is thought to be fueled by increased nutrient loading, a consequence of rapid population and economic growth in the region. To understand the spatiotemporal distribution of algal blooms,
K. Acharya; Y. Li; M. Stone; Z. Yu; M. Young; D. S. Shafer; J. Zhu; J. J. Warwick
Ice-associated phytoplankton blooms in the southeastern Bering Sea can critically impact the food web structure, from lower tropic level production to marine fisheries. By coupling pelagic and sea ice algal components, our 1-D ecosystem model successfully reproduced the observed ice-associated blooms in 1997 and 1999 at the NOAA/PMEL mooring M2. The model results suggest that the ice-associated blooms were seeded by sea ice algae released from melting sea ice. For an ice-associated bloom to grow and reach the typical magnitude of phytoplankton bloom in the region, ice melting-resulted low-salinity stratification must not be followed by a strong mixing event that would destroy the stratification. The ice-associated blooms had little impacts on the annual primary production, but had significant impacts in terms of shifting phytoplankton species, and the timing and magnitude of the bloom. These changes, superimposed on a gradual ecosystem shift attributed to global warming, can dramatically alter the Bering Sea ecosystem.
Jin, Meibing; Deal, Clara; Wang, Jia; Alexander, Vera; Gradinger, Rolf; Saitoh, Sei-ichi; Iida, Takahiro; Wan, Zhenwen; Stabeno, Phyllis
Increased frequency and extent of potentially harmful blooms in coastal and inland waters world-wide require the development of methods for operative and reliable monitoring of the blooms over vast coastal areas and a large number of lakes. Remote sensing could provide the tool. An overview of the literature in this field suggests that operative monitoring of the extent of some
It is suggested that novel nuisance algal blooms can result from major shifts in N\\/P or NH4+\\/NO3- ratios. Inland hydraulic engineering caused a shift from P-limitation (before 1977) towards N-limitation (after 1977) in the Marsdiep area (Dutch coastal waters). Following this shift the colonial flagellate Phaeocystis sp. became more abundant and started to bloom during the nutrient-controlled period (later spring
Roel Riegman; Anna A. M. Noordeloos; Gerhard C. Cadée
Bloom Syndrome (BS) is an autosomal recessive disorder due to mutation in Bloom helicase (referred in literature either as BLM helicase or BLM). Patients with BS are predisposed to almost all forms of cancer. BS patients are even today diagnosed in the clinics by hyper-recombination phenotype that is manifested by high rates of Sister Chromatid Exchange. The function of BLM
Shweta Tikoo; Sagar Sengupta
Phytoplankton blooms are crucial links in many of the earth's biogeochemical cycles. Blooms take up atmospheric carbon through photosynthesis, and sequester it on the ocean floor by sinking. Aggregation of single cells into [open quote]marine snow[close quote] particles speeds up the sinking of algal cells. Laboratory studies investigating the process of aggregation show that some species have a higher probability of aggregating than others, and that there exist several mechanisms for causing aggregation. Field studies confirm that some species are more likely to be found in aggregates than in the surrounding seawater. High latitude Premnesiophyte blooms are found to produce large amounts of dimethylsulflde (DMS), believed to be an important chemical in global thermoregulation. DMS is found to vary diurnally, possibly due to photooxidation by ultraviolet light. This possibility links the effects of DMS on cloud formation with the effects of increased ultraviolet light penetrating the earths ozone layer.
Receiving coastal waters and estuaries are among the most nutrient-enriched environments on earth, and one of the symptoms of the resulting eutrophication is the proliferation of opportunistic, fast-growing marine seaweeds. Here, we used a widespread macroalga often involved in blooms, Ulva spp., to investigate how supply of nitrogen (N) and phosphorus (P), the two main potential growth-limiting nutrients, influence macroalgal growth in temperate and tropical coastal waters ranging from low- to high-nutrient supplies. We carried out N and P enrichment field experiments on Ulva spp. in seven coastal systems, with one of these systems represented by three different subestuaries, for a total of nine sites. We showed that rate of growth of Ulva spp. was directly correlated to annual dissolved inorganic nitrogen (DIN) concentrations, where growth increased with increasing DIN concentration. Internal N pools of macroalgal fronds were also linked to increased DIN supply, and algal growth rates were tightly coupled to these internal N pools. The increases in DIN appeared to be related to greater inputs of wastewater to these coastal waters as indicated by high ?15N signatures of the algae as DIN increased. N and P enrichment experiments showed that rate of macroalgal growth was controlled by supply of DIN where ambient DIN concentrations were low, and by P where DIN concentrations were higher, regardless of latitude or geographic setting. These results suggest that understanding the basis for macroalgal blooms, and management of these harmful phenomena, will require information as to nutrient sources, and actions to reduce supply of N and P in coastal waters concerned.
Teichberg, Mirta; Fox, Sophia E; Olsen, Ylva S; Valiela, Ivan; Martinetto, Paulina; Iribarne, Oscar; Muto, Elizabeti Yuriko; Petti, Monica A V; Corbisier, Thais N; Soto-Jimenez, Martin; Paez-Osuna, Federico; Castro, Paula; Freitas, Helena; Zitelli, Andreina; Cardinaletti, Massimo; Tagliapietra, Davide
Wintertime toxic blooms of the blue-green alga Anabaena flos-aquae have been documented since 1989 in American Lake, a 446-ha lake near Tacoma, Washington. The toxic episodes were unusual in that algal toxicity occurred during the winter and this lake is considered to be only moderately productive. A year-long study was conducted to determine the environmental factors associated with toxic conditions.
Jean M. Jacoby; Harry L. Gibbons; Ray Hanowell; Debra D. Bouchard
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
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
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
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
There is interest in the paradigm that relates environmental sea changes to the emergence of diseases that affect both aquatic organisms in the sea and human beings. The emergence of Vibrio parahaemolyticus as an important cause of epidemic summer diarrhea in 2004 and 2005, confined mainly to the tenth region in Chile, could be a manifestation of this trend. This and other areas of the country have also experienced several outbreaks of paralytic shellfish poisoning (PSP), diarrheal shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP) caused by harmful algal blooms (HAB) of Alexandrium catenella, Dinophysis acuta and Pseudonitzchia species, respectively. The short historical record of these pathological phenomena in Chile suggests that they are increasing in frequency and expanding their geographical range. The V parahaemolyticus isolates responsible for the Chilean outbreaks correspond mainly to the pandemic strain O3:K6. HAB found in Chile and the intoxications caused by them have similar biological characteristics to those described in other areas of the world. The tenth region, the area where these problems are emerging, produces approximately 80-90% of the shellfish consumed in Chile and a large proportion of the shellfish that is exported. Prevention of these public health problems can be attained by developing policies that increase environmental surveillance for Vibrios and toxic algae, improve the epidemiological surveillance of acute diarrhea and algal intoxications after the ingestion of raw bivalves, and educate the population on the mode of transmission of these diseases. Scientific capacity and laboratories need to be developed to widen the limited knowledge of the biology of Vibrio and toxic algae and the environmental factors that favor their emergence as public health and economic problems in Chile. PMID:16311702
Hernández, Cristina; Ulloa, Juanita; Vergara, José Antonio; Espejo, Romilio; Cabello, Felipe
This paper describes a quantitative investigation of relationships between the growth of phytoplankton, and climatic and hydrodynamci conditions in temperate fjords with marked tides, as exemplified by Puget Sound, Washington (USA). Algal growth in the open waters of the central basin of the Sound is dominated by a number of intense blooms beginning in late April or May and recurring
D. F. Winter; K. Banse; G. C. Anderson
Blooms of opportunistic green macro-algae are a common feature of coastal areas and their effects on mudflat invertebrates can be dramatic. On the Ythan estuary, Aberdeenshire, Scotland, we have carried out a number of manipulative field experiments designed to evaluate the effects on invertebrates of different species of macro-algae with contrasting ecologies, and the effects of invertebrates on the development of the blooms. Macro-algal mats were found to have dramatic nega- tive effects on the density of the amphipod Corophium volutator, with higher algal biomasses having greater impact. The mechanism for this interaction seems to be interference by the algal filaments with the feeding behaviour of the amphipod. In contrast, the polychaete Capitella spp. increases in abundance under macro-algal mats due to enrichment of the sediment with organic material. These two interactions are seen at all scales, in areas of less than 1 m2 to the scale of the entire estuary, irrespective of the species composition of the macro- algal mats. Bioturbation by Corophium and grazing by the snail Hydrobia ulvae had little effect on macro-algal biomass, but there were less algae when the polychaete Nereis diversicolor was present. The most significant interaction in this system is the pronounced negative impact of algal mats on the abundance of Corophium, probably the most important invertebrate species in the diets of the estuary's shorebirds, fish and epibenthic crustaceans.
The bloom filter is a probabilistic data structure that provides a compact representation of a set of elements. To keep false positive probabilities low, the size of the bloom filter must be dimensioned a priori to be linear in the maximum number of keys inserted, with the linearity constant ranging typically from one to few bytes. A bloom filter is
Biplob Debnath; Sudipta Sengupta; Jin Li; David J. Lilja; David H. C. Du
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
Eutrophication has become a serious concern in many lakes, resulting in cyanobacterial blooms. However, the mechanism and pathways of cyanobacteria decline are less understood. To identify and define the growth and decline of Microcystis blooms in Taihu Lake of China, and to illuminate the destination of surface floating blooms, we investigated the biomass distribution and variations in colony size, morphology, and floating velocity from October 2008 to September 2009. The results showed that the Microcystis bloom declined in response to biomass decrease, colony disaggregation, buoyancy reduction, and increased phytoplankton biodiversity, and these indicative parameters could be applied for recognition of the development phases of the bloom. Three major decline pathways were proposed to describe the bloom decline process, colony disaggregation (Pathway I), colony settlement (Pathway II), and cell lysis in colonies (Pathway III). We proposed a strategy to define the occurrence and decline of Microcystis blooms, to evaluate the survival state under different stress conditions, and to indicate the efficiency of controlling countermeasures against algal blooms.
Wang, Zhicong; Li, Guowen; Li, Genbao; Li, Dunhai
We have applied a normalized difference algorithm to 8 day composite chlorophyll-a (CHL) and fluorescence line height (FLH) imagery obtained from the Moderate Resolution Imaging Spectroradiometer aboard the Aqua spacecraft in order to detect and monitor phytoplankton blooms in the Oregon coastal region. The resulting bloom products, termed CHLrel and FLHrel, respectively, describe the onset and advection of algal blooms as a function of the percent relative change observed in standard 8 day CHL or FLH imagery over time. Bloom product performance was optimized to consider local time scales of biological variability (days) and cloud cover. Comparison of CHLrel and FLHrelretrievals to in situ mooring data collected off the central Oregon coast from summer 2009 through winter 2010 shows that the products are a robust means to detect bloom events during the summer upwelling season. Evaluation of winter performance was inconclusive due to persistent cloud cover and limited in situ chl-a records. Pairing the products with coincident in situ physical proxies provides a tool to elucidate the conditions that induce bloom onset and identify the physical mechanisms that affect bloom advection, persistence, and decay. These products offer an excellent foundation for remote bloom detection and monitoring in this region, and the methods developed herein are applicable to any region with sufficient CHL and FLH coverage.
McKibben, S. M.; Strutton, P. G.; Foley, D. G.; Peterson, T. D.; White, A. E.
Bloom's Taxonomy is difficult to apply consistently to assessment tasks in introductory programming courses. The Bloom taxonomy is a valuable tool that could enable analysis and discussion of programming assessment if it could be interpreted consistently. We discuss each of the Bloom classification categories and provide a consistent interpretation with concrete exemplars that will allow computer science educators to utilise
Errol Thompson; Andrew Luxton-Reilly; Jacqueline L. Whalley; Minjie Hu; Phil Robbins
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
Many land plants are known to possess toxins, presumably for grazer deterrence, whereas toxins in marine phytoplankton are a much rarer phenomenon, particularly in open ocean (blue water) environments. Several dozen phytoplankton species, frequently dinoflagellates but also some diatoms, form "harmful algal blooms" nearshore: here their toxins can contaminate filter-feeding shellfish resulting in poisoning "syndromes" when humans consume the tainted shellfish. The present rise in such coastal events is a likely consequence of human activities. In blue water, open ocean environments, the filamentous cyanobacterium Trichodesmium (a blue green alga) is one of the few bloom-forming toxin producers and hosts a consortium of microorganisms that may be partially immune to its toxins. Pseudo-nitzschia, a ubiquitous genus of diatoms recently has been shown to include coastal species that produce domoic acid (DA), a neurotoxin that passes through the food web, sometimes with resulting deaths of marine birds and mammals. Oceanic species of Pseudo-nitzschia also exist but are less well known, and DA has not yet been found in them. Here we review some general features of toxic marine phytoplankton, recent studies on DA in coastal ecosystems and describe some of our findings on blue water Pseudo-nitzschia. We will summarize laboratory experiments that show complex patterns of DA retention and release into the water when Fe is added to coastal Pseudo-nitzschia cultures. In oceanic species, equivalent experiments on cell physiology are limited and the natural species and abundance patterns poorly known. Here we present our recent discovery that DA occurs in oceanic Pseudo-nitzschia and review evidence from the literature that this genus may be preferentially enhanced when iron is added to HNLC (high nutrient, low chlorophyll) waters: areas where nitrogen and phosphorus are not yet depleted, but iron concentrations and phytoplankton biomass are low. The rapid growth of these DA-producing diatoms with iron addition is worrisome, as a proposed solution for reducing atmospheric carbon dioxide involves iron fertilization of HNLC waters, which encompass large areas of the open sea. We speculate on possible ecosystem consequences of iron fertilization as a remedy to abate global warming and the likely promotion of toxic Pseudo-nitzschia blooms. Such enrichment, however, may not be totally unprecedented, as oceanic deposition of iron-rich dust may also have occurred naturally, promoting these toxin producers during past ocean conditions.
Silver, M. W.; Bargu, S.
Cyanobacteria bloom occurs constantly in recent years and seriously harms the environment of people's life. Lake Dianchi is a typical lake that has been subjected to severe eutrophication in recent years, especially in 2010. This article describes new-type, dynamic, high-quality images of Environment Satellite HJ-1 CCD applied to view cyanobacteria bloom of Lake Dianchi, ranging from November to December in
Jie Zhang; Jian Chen
In the Baltic Sea, increased dominance of ephemeral and bloom-forming algae is presently attributed to increased nutrient loads. Simultaneously, coastal predatory fish are in strong decline. Using field data from nine areas covering a 700-km coastline, we examined whether formation of macroalgal blooms could be linked to the composition of the fish community. We then tested whether predator or nutrient availability could explain the field patterns in two small-scale field experiments, by comparing joint effects on algal net production from nutrient enrichment with agricultural fertilizer and exclusion of larger predatory fish with cages. We also manipulated the presence of invertebrate grazers. The abundance of piscivorous fish had a strong negative correlation with the large-scale distribution of bloom-forming macroalgae. Areas with depleted top-predator communities displayed massive increases in their prey, small-bodied fish, and high covers of ephemeral algae. Combining the results from the two experiments showed that excluding larger piscivorous fish: (1) increased the abundance of small-bodied predatory fish; (2) changed the size distribution of the dominating grazers, decreasing the smaller gastropod scrapers; and (3) increased the net production of ephemeral macroalgae. Effects of removing top predators and nutrient enrichment were similar and additive, together increasing the abundance of ephemeral algae many times. Predator effects depended on invertebrate grazers; in the absence of invertebrates there were no significant effects of predator exclusion on algal production. Our results provide strong support for regional declines of larger predatory fish in the Baltic Sea promoting algal production by decreasing invertebrate grazer control. This highlights the importance of trophic interactions for ecosystem responses to eutrophication. The view emerges that to achieve management goals for water quality we need to consider the interplay between top-down and bottom-up processes in future ecosystem management of marine resources. PMID:20014572
Eriksson, Britas Klemens; Ljunggren, Lars; Sandström, Alfred; Johansson, Gustav; Mattila, Johanna; Rubach, Anja; Råberg, Sonja; Snickars, Martin
Population dynamics of the dominant calanoid copepods Acartia spp. and Tempora longicornis were followed during a dense spring bloom of Phaeocystis pouchetii in the northern Wadden Sea off Sylt. Positive correlations between algal concentration and abundance of the copepod species suggest that P. pouchetii constitutes an important food organism for the copepods in spring and early summer. In laboratory experiments,
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.
Harmful algae are a worldwide problem. Phycotoxins is a general term for toxic compounds produced by harmful species of the phytoplankton. This review deals with the occurrence of harmful algae and phycotoxins in the Baltic Sea and other domestic waters, the ways of getting exposed to them, and their effects. Advice on how to avoid the exposure is provided. PMID:21834336
Kankaanpää, Harri T
We tested the hypothesis that there would be measurable losses of phosphorus (P) from surficial sediments of Upper Klamath\\u000a Lake (UKL), Oregon, if sediments were a source of P during an algal bloom. We compared concentrations of total and forms of\\u000a P at various depths in cores collected before and after the onset of a large Aphanizomenon flos-aquae bloom. Concentrations
Nancy S. Simon; Dennis Lynch; Thomas N. Gallaher
The longevity (>50d) of the phytoplankton bloom following mesoscale iron-enrichment of Southern Ocean waters (SOIREE) exceeded that for naturally occurring polar blooms (15-20d). During SOIREE, SF6-labelled waters increased 20-fold, and the greatest algal loss term was lateral advection. To test whether such advective losses could delay the onset of mass sedimentation, an algal aggregation model was employed. It successfully simulated temporal trends in mass sedimentation during the tropical IronEx II bloom, yet suggested no such event during SOIREE. However, when an iron-enrichment of 100 km length-scale (i.e. tenfold greater than for SOIREE) was mimicked, a marked increase in algal aggregate size occurred after 15d, indicative of increased export. Thus, careful interpretation of experimental results-especially for the fate of algal carbon-is essential, particularly for polar studies where the ratio of net algal growth to advective losses is low, if they are to be extrapolated to open-ocean waters.
Boyd, Philip W.; Jackson, George A.; Waite, Anya M.
Abstract In the application of the Original Bloom’s taxonomy since its publication in 1956, se- veral weaknesses and practical limitations have been revealed. Besides, psychological and educational research has witnessed the introduction of several theories and approaches to learning which ,make ,students more ,knowledgeable ,of and ,responsible for their own learning, cognition, and thinking. Hence, a group of researchers revised
This paper considers space-efficient data structures for storing an approximation S' to a set S such that S ? S' and any element not in S belongs to S' with probability at most ?. The Bloom filter data structure, solving this problem, has found widespread use. Our main result is a new RAM data structure that improves Bloom filters in
Anna Pagh; Rasmus Pagh; S. Srinivasa Rao
Discusses parallels between Bloom's taxonomy for cognitive learning outcomes and hypertext design, and argues that hypertext designs should be consistent with desired learning outcomes. Bloom's taxonomy is explained; hypertext designs are described and diagrammed; and the need for more research connecting hypertext design and effective learning is…
Ross, Tweed W.
We examined the growth and interactions between the bloom-forming flagellates Prorocentrum minimum and Heterosigma akashiwo using bi-algal culture experiments. When both species were inoculated at high cell densities, growth of H. akashiwo was inhibited by P. minimum. In other combinations of inoculation densities, the species first reaching the stationary phase substantially suppressed\\u000a maximum cell densities of the other species, but
Y. Yamasaki; S. Nagasoe; M. Tameishi; T. Shikata; Y. Zou; Z. Jiang; T. Matsubara; Y. Shimasaki; K. Yamaguchi; Y. Oshima; T. Oda; T. Honjo
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.
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
We characterized the community composition of phytoplankton in the western subarctic Pacific from the pre-bloom to the decline phase of the spring bloom with special reference to decreases in the silicic acid concentration in surface waters as an index for diatom bloom development. Furthermore, responses of heterotrophic bacteria and viruses to the spring bloom were also concomitantly investigated. Under pre-bloom conditions when nutrients were abundant but the surface mixed layer depth was relatively deep, chlorophyll (Chl) a concentrations were consistently low and green algae (chlorophytes and prasinophytes), cryptophytes, and diatoms were predominant in the phytoplankton assemblages as estimated by algal pigment signatures. Together with the shallowing of the mixed layer depth and the decrease in silicic acid concentration, diatoms bloomed remarkably in the Oyashio region, though the magnitude of the bloom in the Kuroshio-Oyashio transition (hereafter Transition) region was relatively small. A total of 77 diatom species were identified, with the bloom-forming diatoms mainly consisting of Thalassiosira, Chaetoceros, and Fragilariopsis species. It has become evident that the carotenoid fucoxanthin can serve as a strong indicator of the diatom carbon biomass during the spring diatom bloom. Differences in the species richness of diatoms among stations generally enabled us to separate the Oyashio bloom stations from the Transition and the Oyashio pre-bloom stations. Relatively high values of the Shannon-Wiener index for the diatom species were also maintained during the Oyashio bloom, indicating that a wide variety of species then shared dominance. In the decline phase of the Oyashio bloom when surface nutrient concentrations decreased, senescent diatom cells increased, as inferred from the levels of chlorophyllide a. Although the cell density of heterotrophic bacteria changed little with the development of the diatom bloom, viral abundance increased toward the end of the bloom, suggesting an increased likelihood of mortality among organisms including diatoms resulting from viral infection. This is the first report on the microbial trophodynamics, including viruses, during the spring diatom bloom in the western subarctic Pacific.
Suzuki, Koji; Kuwata, Akira; Yoshie, Naoki; Shibata, Akira; Kawanobe, Kyoko; Saito, Hiroaki
Lytic viruses have been implicated in the massive cellular lysis observed during algal blooms, through which they assume a prominent role in oceanic carbon and nutrient flows. Despite their impact on biogeochemical cycling, the transcriptional dynamics of these important oceanic events is still poorly understood. Here, we employ an oligonucleotide microarray to monitor host (Emiliania huxleyi) and virus (coccolithovirus) transcriptomic features during the course of E. huxleyi blooms induced in seawater-based mesocosm enclosures. Host bloom development and subsequent coccolithovirus infection was associated with a major shift in transcriptional profile. In addition to the expected metabolic requirements typically associated with viral infection (amino acid and nucleotide metabolism, as well as transcription- and replication-associated functions), the results strongly suggest that the manipulation of lipid metabolism plays a fundamental role during host-virus interaction. The results herein reveal the scale, so far massively underestimated, of the transcriptional domination that occurs during coccolithovirus infection in the natural environment. PMID:22066669
Pagarete, António; Le Corguillé, Gildas; Tiwari, Bela; Ogata, Hiroyuki; de Vargas, Colomban; Wilson, William H; Allen, Michael J
Heterosigma akashiwo virus (HaV) is a large double-stranded DNA virus infecting the single-cell bloom- forming raphidophyte (golden brown alga) H. akashiwo. A molecular phylogenetic sequence analysis of HaV DNA polymerase showed that it forms a sister group with Phycodnaviridae algal viruses. All 10 examined HaV strains, which had distinct intraspecies host specificities, included an intein (protein intron) in their DNA
Keizo Nagasaki; Yoko Shirai; Yuji Tomaru; Kensho Nishida; Shmuel Pietrokovski
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
The term self-harm is commonly used to describe a wide range of behaviours and intentions including attempted hanging, impulsive self-poisoning, and superficial cutting in response to intolerable tension. As with suicide, rates of self-harm vary greatly between countries. 5-9% of adolescents in western countries report having self-harmed within the previous year. Risk factors include socioeconomic disadvantage, and psychiatric illness--particularly depression, substance abuse, and anxiety disorders. Cultural aspects of some societies may protect against suicide and self-harm and explain some of the international variation in rates of these events. Risk of repetition of self-harm and of later suicide is high. More than 5% of people who have been seen at a hospital after self-harm will have committed suicide within 9 years. Assessment after self-harm includes careful consideration of the patient's intent and beliefs about the lethality of the method used. Strong suicidal intent, high lethality, precautions against being discovered, and psychiatric illness are indicators of high suicide risk. Management after self-harm includes forming a trusting relationship with the patient, jointly identifying problems, ensuring support is available in a crisis, and treating psychiatric illness vigorously. Family and friends may also provide support. Large-scale studies of treatments for specific subgroups of people who self-harm might help to identify more effective treatments than are currently available. Although risk factors for self-harm are well established, aspects that protect people from engaging in self-harm need to be further explored. PMID:16243093
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
We study the evolution of the plankton bloom modelled by the excitable model sug- gested by Truscott and Brindley, 1994, in the presence of stirring by an oceanic flow. It is shown that the coupled system has an advectively propagating mode correspond- ing to a non-decaying bloom filament increasing in length, that can be activated by a transient localised perturbation in a small area. Potential implications for 'ocean fertilization' experiments are also discussed.
Neufeld, Z.; Haynes, P. H.; Garcon, V. C.; Sudre, J.
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
A survey of Rodney's Rock was executed and algal species were observed and identified. Sample areas were studied to determine species present and percent coverage. All species identifiable in the area were recorded. Thirteen algal species were identified. In sample area 1 the two dominant species were an unidentifiable brown algae and a green alga, Bryopsis pulmosa. In sample area
Sean Duncan; Susan Harvey
This paper presents an overview of dimethyl sulphide biogeochemistry within a coccolithophore bloom (DISCO), an integrated, multidisciplinary Lagrangian process study of the routes, rates and controls on the biogeochemical cycling of dimethyl sulphide (DMS) within a growing bloom of the coccolithophorid alga, Emiliania huxleyi. The Lagrangian study took place between 16 and 26 June 1999 in the northern North Sea. It was preceded by an 8-d survey of ˜52,000 km 2 of the region to locate an E. huxleyi bloom suitable for study. Although not originally planned, the survey was carried out because heavy cloud cover precluded use of remote sensing to locate a suitable bloom. E. huxleyi blooms, typically common in the region during mid-summer, were unusually sparse in the study area. The bloom chosen for the process study was initially centred ˜58°56'N 02°52'E, and a 40-km 2 patch of water was labelled for study with ˜30 g sulphur hexafluoride (SF 6) on 16 June. The original patch was reinfused with further SF 6 on 24 June. During the process study, the SF 6-labelled patch moved in a south-easterly direction and the study ended when the patch subducted underneath less dense Norwegian coastal water. The process study comprised analyses of the time-varying biological, optical and physical properties of the patch as well as studies of DMS, dimethylsulphonioproprionate (DMSP), dimethylsulphoxide, nutrients, halocarbons, methylamines, carbon monoxide, dissolved organic carbon, and total dissolved nitrogen. The role of viruses, bacteria, phytoplankton, microzooplankton, and mesozooplankton, together with the dynamics of primary, new and bacterial production, plankton respiration, microzooplankton grazing, and sedimentation, were studied in relation to the biogeochemical cycling of DMS. Although the coccolithophore bloom water exhibited high optical backscatter, the algal community present was highly heterogeneous. Flagellates other than E. huxleyi were found to dominate the phytoplankton. A budget of the DMSP pools suggested that E. huxleyi accounted for only 13% of the stocks of particulate DMSP, showing that in this " E. huxleyi bloom", taxa other than E. huxleyi were important sources of DMSP. In this young bloom, particulate and dissolved DMSP and DMS concentrations averaged 1360, 155 and 60 ?M m -2, respectively, in the surface mixed layer. Surface-water particulate DMSP concentrations increased during the study at a net rate of 13% d -1, as did concentrations of phytoplankton including E. huxleyi, confirming that the bloom was developing. Nutrient conditions were low in the mixed layer throughout the study, maintained by a strong pycnocline across which nitrate upflux was estimated to be ˜2 nM dm -3 d -1. Primary production was fuelled by regenerated nutrients, although nitrification rates in surface waters were found to be significant. Microzooplankton grazing accounted for 91% of the particulate DMSP degradation and was considered to be a major control on the DMSP concentration. Vigorous microzooplankton grazing together with rapid uptake of dissolved DMSP by bacteria suggest that microzooplankton were the main route for the production of dissolved DMSP. The bacterial community was dominated by one taxon, an ? proteobacteria related to Roseobacter that satisfied its entire sulphur demand by metabolising dissolved DMSP. Bacteriogenic DMS production amounted to 2 nM d -1 and was considered the main route for DMS production. In vitro DMSPlyase activity was very high, but there was little evidence for high in situ activity. Over the study period, DMS flux to the atmosphere was estimated to be 7 ?M m -2 d -1, equivalent to ˜1% of the DMSP sulphur produced in the surface mixed layer. A budget for DMS cycling in the upper mixed layer is presented based on the analytical and experimental measurements made in the DISCO study.
Burkill, Peter H.; Archer, Stephen D.; Robinson, Carol; Nightingale, Philip D.; Groom, Stephen B.; Tarran, Glen A.; Zubkov, Mikhail V.
It has been well documented that heavy metal accumulation in environment is harmful for living organisms at even trace levels. A new voltammetric algal sensor based on Phormidium sp. modification for Pb(II) determination from aqueous solutions was developed, and selectivity of the biomass to Pb(II) was investigated comprehensively. Many important experimental parameters were performed by using electrochemical techniques, including cyclic
Meral Yüce; Hasan Naz?r; Gönül Dönmez
Identification of phytoplankton groups from space is essential to map and monitor algal blooms in coastal waters, but remains a challenge due to the presence of suspended sediments and dissolved organic matter which interfere with phytoplankton signal. On the basis of field measurements of remote sensing reflectance (Rrs(?)), bio-optical parameters, and phytoplankton cells enumerations, we assess the feasibility of using multispectral and hyperspectral approaches for detecting spring blooms of Phaeocystis globosa (P. globosa). The two reflectance ratios (Rrs(490)/Rrs(510) and Rrs(442.5)/Rrs(490)), used in the multispectral inversion, suggest that detection of P. globosa blooms are possible from current ocean color sensors. The effects of chlorophyll concentration, colored dissolved organic matter (CDOM), and particulate matter composition on the performance of this multispectral approach are investigated via sensitivity analysis. This analysis indicates that the development of a remote sensing algorithm, based on the values of these two ratios, should include information about CDOM concentration. The hyperspectral inversion is based on the analysis of the second derivative of Rrs(?) (d?2Rrs). Two criteria, based on the position of the maxima and minima of d?2Rrs, are established to discriminate the P. globosa blooms from diatoms blooms. We show that the position of these extremes is related to the specific absorption spectrum of P. globosa and is significantly correlated with the relative biomass of P. globosa. This result confirms the advantage of a hyperspectral over multispectral inversion for species identification and enumeration from satellite observations of ocean color.
Lubac, Bertrand; Loisel, Hubert; Guiselin, Natacha; Astoreca, Rosa; Felipe Artigas, L.; MéRiaux, Xavier
A harmful bloom due to the raphidophycean flagellate, Chattonella antiqua, was found in the Yatsushiro Sea, western Kyushu, Japan, from the end of July to the beginning of August 2009. The bloom resulted in enormous economic damage to cultured finfish production in aquaculture farms concentrated in the southwestern area. To investigate the factors controlling the spatio-temporal distribution of the bloom, data analysis and numerical simulations were conducted using field monitoring data and a three-dimensional hydrodynamic model coupled to a Lagrangian particle-tracking model. Results of the monitoring data analysis showed that the initial development of the C. antiqua bloom occurred in Kusuura Bay and the northeastern area near the mouth of the Kuma River, and subsequently the bloom expanded rapidly to the whole area. The simulation results indicated that the source region of the widespread bloom was not Kusuura Bay but the northeastern area. The southwestward evolution of the bloom was primarily controlled by the passive transport due to the surface residual current driven by fresh water discharge from the Kuma River and northeasterly winds. On the favorable conditions of river discharge and wind, the massive bloom of C. antiqua that formed in the northeastern area was quickly transported southwestward within a few days.
Aoki, Kazuhiro; Onitsuka, Goh; Shimizu, Manabu; Kuroda, Hiroshi; Matsuyama, Yukihiko; Kimoto, Katsunori; Matsuo, Hitoshi; Kitadai, Yuuki; Sakurada, Kiyonari; Nishi, Hiromi; Tahara, Yoshio
This webpage explains Bloom's Taxonomy, and also features ideas for revising and rethinking the ordering of the steps in the hierarchy. A copy of Bloom's Taxonomy with sample verbs and a sample behavior statement for each level is also included.
Huitt, W.; University, Valdosta S.
Blooms of cyanobacteria have appeared on the Potomac River near Washington, DC in years of drought and low river volume. The location of the bloom may be related to tidal activity. In 1983, the bloom of Microcystis aeruginosa used ammonia as its nitrogen source and contained low levels of toxic peptides. Cells collected from this bloom proved to be homogeneous and were an excellent source material for the isolation of proteins involved in photosynthesis. PMID:16664682
Krogmann, D W; Butalla, R; Sprinkle, J
During the last two decades, large-scale high biomass algal blooms of the dinoflagellate Prorocentrum donghaiense Lu have occurred frequently in the East China Sea (ECS). The role of increasing nutrient concentrations in driving those blooms is well-established, but the source population that initiates them is poorly understood. We hypothesized that the front of Taiwan Warm Current (TWC) may serve as a 'seed bank' that initiates P. donghaiense blooms in the ECS, as the physiochemical conditions in the TWC are suitable for the growth of P. donghaiense. In order to test this hypothesis, two surveys at different spatio-temporal scales were conducted in 2010 and 2011. We found a strong correlation in space and time between the abundance of P. donghaiense and the TWC. The spatial extent of the P. donghaiense bloom coincided with the TWC front in both 2010 and 2011. During the early development of the blooms, P. donghaiense concentration was highest at the TWC front, and then the bloom mass shifted inshore over the course of our 2011 survey. The TWC also moved inshore, albeit after the appearance of P. donghaiense. Overall, these results support our hypothesis that P. donghaiense blooms develop from the population at the TWC front in the ECS, suggesting the role of the ocean current front as a seed bank to dinoflagellate blooms. PMID:23671709
Dai, Xinfeng; Lu, Douding; Guan, Weibing; Xia, Ping; Wang, Hongxia; He, Piaoxia; Zhang, Dongsheng
As of 1996 the 100th cancer was diagnosed in Bloom's syndrome. The cancers have been regularly documented since 1960 in a program of surveillance referred to as the Bloom's Syndrome Registry. Tabulated here are their types and ages of onset. The 100 cancers arose in 71 of the 168 registered individuals. Represented in Bloom's syndrome are both the cancers that
Bloom's taxonomy, which has been influential in underpinning many of the curriculum developments of the last fifteen years, may be criticized on various grounds. It is a mistake to suppose that Bloom's taxonomy, or any other proposed classification of objectives, can ever be wholly independent of questions of value. On the contrary, it appears that Bloom's taxonomy ‘suits’ the expression
C. P. Ormell
The new bloom caster at Sumitomo Metal's Wakayama Steel Works was succesfully commissioned in January 1979. This bloom caster is characterized by the fact that the operations of the tube round making are fully controled by computer systems through all the processes: refining steels, casting blooms and rolling billets. The nominal monthly production capacity of 80,000 metric tons was recorded
Sumio Ishikawa; Akiyoshi Mori; Moriaki Yoshioka; Tsutomu Nagahata; Tsuneaki Kobayashi
The traditional approach to introductory programming has students writing complete programs, as early as possible. Also, the traditional emphasis is on the technology, not the explicit cognitive development of the student. This approach jumps to the fifth and sixth levels of Bloom's Taxonomy of Educational Objectives, when these last two levels depend upon competence in the first four levels. I
In early 2006, unusual algal blooms of two species occurred in the Salton Sea, a large salt lake in southern California. In mid-January local residents reported bioluminescence in the Sea. Starting in February, large rafts of long-lasting foam, also bioluminescent, were observed as well. Microscopy investigations on water and sediment samples collected in March showed the marine dinoflagellate, Alexandrium margalefii, and the prymnesiophyte, Prymnesium sp., both previously unreported in the Salton Sea, to be abundant. Bioluminescence and foam production continued through March. Other dinoflagellate species, recorded during earlier studies, were rare or not detected during these blooms. Despite the fact that many Alexandrium species are known paralytic shellfish poison (PSP) producers, preliminary saxitoxin tests on this population of A. margalefii were negative. Previous reports on A. margalefii do not mention bioluminescence. It appears that the foam was caused by the Prymnesium sp. bloom, probably via protein-rich exudates and lysis of other algal cells, and its glow was due to entrained A. margalefii. This is the first report of A. margalefii in U.S. waters and the first report of it in a lake.
Tiffany, Mary A.; Wolny, Jennifer; Garrett, Matthew; Steidinger, Karen; Hurlbert, Stuart H.
The harm that each individual causes others is unverifiable in some circumstances where the total harm caused by everyone is verifiable. For example, the environmental agency can often measure the total harm caused by pollution much easier than it can measure the harm caused by each individual polluter. In these circumstances, implementing the usual liability rules or externality taxes is
Robert D. Cooter; Ariel Porat
The transfer of marine algal toxins involving a range of phytoplanktivorous vectors is well documented as a means of exposing organisms at higher trophic levels (including humans) to these naturally occurring yet harmful compounds. While previous studies have examined the potential for, and dynamics of, algal toxin accumulation by individual zooplankton species, few have attempted to distinguish the contribution of
Gregory J. Doucette; Jefferson T. Turner; Christine L. Powell; Bruce A. Keafer; Donald M. Anderson
|In the application of the "Original" Bloom's taxonomy since its publication in 1956, several weaknesses and practical limitations have been revealed. Besides, psychological and educational research has witnessed the introduction of several theories and approaches to learning which make students more knowledgeable of and responsible for their own…
The harmful marine dinoflagellate, Karenia brevis, frequently forms large toxic blooms in the waters off the west coast of Florida (USA), and is responsible for massive fish kills and public health concerns. Despite decades of field studies on this organism, no investigation has yet examined the li...
We propose Remote Harm-Diagnostics (RHD) as a new de- fensive tactic against malware and phishing attacks. RHD is a server-side tool that harvests data from clients to detect signs of previous or ongoing compromise. RHD can sup- plement client-side protections such as virus checkers and anti-phishing toolbars. Given its \\
Markus Jakobsson; Ari Juels; Jacob Ratkiewicz
Massive blooms of the harmful alga Cochlodinium polykrikoides Margalef occurred in the lower Chesapeake Bay and its tributaries during the summers of 2007 and 2008. The Lafayette and\\u000a Elizabeth Rivers appeared to act as initiation grounds for these blooms during both years. However, in 2008 there were also\\u000a localized sites of initiation and growth of populations within the mesohaline portion
Ryan E. Morse; Jian Shen; Jose L. Blanco-Garcia; William S. Hunley; Scott Fentress; Mike Wiggins; Margaret R. Mulholland
A hepatotoxic cyanobacterial (blue-green algal) water bloom was collected from a constructed water reservoir in Finland. The water bloom contained two cyanobacterial species, Microcystis aeruginosa and Aphanizomenon flos-aquae. Two hepatotoxins, 1 and 2, were isolated from extracts of lyophilized cells. The structures of 1 and 2 were assigned based upon their amino acid analyses on a Waters Pico Tag HPLC system and a chiral GC capillary column (Chirasil Val III), fast atom bombardment mass spectrometry (FABMS), high resolution FABMS, and tandem FABMS data. Toxin 1 was identical to a previously reported compound, [D-Asp3]microcystin-RR. Toxin 2 was new and was assigned the structure [D-Asp3]microcystin-YR. PMID:1485342
Namikoshi, M; Sivonen, K; Evans, W R; Sun, F; Carmichael, W W; Rinehart, K L
Michigan's Appellate Court ruled in 2004 that a pregnancy that resulted from a rape should be considered a bodily injury for sentencing purposes. Interestingly, all three possible outcomes of a pregnancy-abortion, miscarriage, or childbirth-are considered to bring with them significant and substantial physical, psychological, and emotional changes. While the immediate impact of the ruling in People v. Cathey affected only the guilty individual, there are larger implications for this ruling beyond just sentencing guidelines. The ruling can be considered a step forward in prosecuting rapists, but possibly at the expense of reimagining the female body. This article considers the Cathey ruling itself, the potential benefits and consequences of this understanding on feminist discourse, and, crucially, the impact of this decision on abortion discussions. The central question that emerges is, can we both consider pregnancy a harm and believe that this harm is not always wrong-making? PMID:22643758
Kraft, Rory E
Although drugs are haram and therefore prohibited in Islam, illicit drug use is widespread in many Islamic countries throughout the world. In the last several years increased prevalence of this problem has been observed in many of these countries which has in turn led to increasing injecting drug use driven HIV/AIDS epidemic across the Islamic world. Whilst some countries have recently responded to the threat through the implementation of harm reduction programmes, many others have been slow to respond. In Islam, The Quran and the Prophetic traditions or the Sunnah are the central sources of references for the laws and principles that guide the Muslims' way of life and by which policies and guidelines for responses including that of contemporary social and health problems can be derived. The preservation and protection of the dignity of man, and steering mankind away from harm and destruction are central to the teachings of Islam. When viewed through the Islamic principles of the preservation and protection of the faith, life, intellect, progeny and wealth, harm reduction programmes are permissible and in fact provide a practical solution to a problem that could result in far greater damage to the society at large if left unaddressed. PMID:20006483
Kamarulzaman, A; Saifuddeen, S M
From 15 to 28 August in 2007, a Chaetoceros socialis bloom was detected in the Pearl River Estuary water with chlorophyll a concentration (Chl a) up to 30 mg m -3 and cell density up to 10 6 cells L -1. Time series of bio-optical measurements was obtained at a single site (114.29°E, 22.06°N) with the mooring of marine optical buoy. Light absorption properties of seawater experienced large variability throughout the algal bloom. Absorption by colored dissolved organic matter (CDOM) was one of the dominant optical components of the light absorption (30-70%) especially for pre- and post-bloom waters, and it tended to decrease with Chl a during the algal bloom. Absorption by phytoplankton was another dominant optical component (18-50%) and increased rapidly with Chl a. Phytoplankton and accompanying material played dominant roles in light absorption as indicated by the relationship between absorption coefficient and Chl a. At high pigment concentrations, water samples showed significantly lower specific phytoplankton absorption, compared with pre- and post-bloom conditions, with the specific phytoplankton concentration at 443 nm varied between 0.011 and 0.022 m 2 mg -1 and that at 676 nm between 0.007 and 0.018 m 2 mg -1; small values of blue-to-red ratio of phytoplankton were also observed. These lower values were associated with variations in phytoplankton size structure. Spectral variability of phytoplankton absorption and total absorption (not including the fixed background absorption by pure water itself) could be expressed as simple linear functions linking absorption at one wavelength to the absorption at the other wavelengths, with the slope of the relationship changing with wavelength. The absorption coefficients by non-algal particles and CDOM follow the general exponential functions with remarkably limited variability in the exponent with means of 0.0105 and 0.0166 nm -1, respectively. These spectral dependencies of absorption coefficients provide useful information for retrieving inherent optical properties from reflectance data in a remote-sensing context.
Wang, Guifen; Cao, Wenxi; Yang, Yuezhong; Zhou, Wen; Liu, Sheng; Yang, Dingtian
By a systematic survey of the parameter space we confirm our surmise [C.S. Aulakh, MSGUTs from germ to bloom: Towards falsifiability and beyond, hep-ph\\/0506291] that the Minimal Supersymmetric GUT (MSGUT) based on the 210?126?126¯?10 Higgs system is incompatible with the generic Type I and Type II seesaw mechanisms. The incompatibility of the Type II seesaw mechanism with this MSGUT is
Charanjit Singh Aulakh; Sumit Kumar Garg
This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Algae blooms routinely threaten the health of the Chesapeake Bay. Phosphate compounds supply a rich source of nutrients for the algae, Prorocentrum min...
There is increasing evidence that bacterial–algal interactions play a role in Harmful Algal Bloom (HAB) ecology. Bacteria that are associated with bloom-forming algal species, specifically toxic dinoflagellate algae, have been implicated in the production and biotransformation of paralytic shellfish toxins (PSTs). To clarify the role that these bacteria may play in the production of PSTs, it is desirable to identify
K. Töbe; C. Ferguson; M. Kelly; S. Gallacher; L. K. Medlin
Text VersionHarm reduction in nicotine addiction Helping people who can't quit ... 236 Harm reduction in nicotine addiction CASAA Dissolvables - Attachment 7 2 ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials
Biomass autoflocculation in outdoor algal cultures was found to be associated with increases of culture pH levels, due to COâ consumption by the algal photosynthetic activity. Under these alkaline conditions, some medium chemical ions precipitated together with the algal biomass. The chemical substances involved with the process and its dependence on pH value were studied by simulation of autoflocculation in
A. Sukenik; G. Shelef
The harm thesis—the assumption that words harm people—is a defining feature of sexual harassment, hate speech, verbal abuse, and obscene telephone call (OTC) offenses. This thesis ignores the possibility that swearing can be advantageous, cathartic, or an acceptable substitute for physical aggression. Observational data, courtroom evidence and verbal abuse research reviewed here produce conflicting conclusions on the question of harm.
The interannual to decadal variability in the timing and magnitude of the North Atlantic phytoplankton bloom is examined using a combination of satellite data and output from an ocean biogeochemistry general circulation model. The timing of the bloom as estimated from satellite chlorophyll data is used as a novel metric for validating the model's skill. Maps of bloom timing reveal that the subtropical bloom begins in winter and progresses northward starting in May in subpolar regions. A transition zone, which experiences substantial interannual variability in bloom timing, separates the two regions. Time series of the modeled decadal (1959-2004) variability in bloom timing show no long-term trend toward earlier or delayed blooms in any of the three regions considered here. However, the timing of the subpolar bloom does show distinct decadal-scale periodicity, which is found to be correlated with the North Atlantic Oscillation (NAO) index. The mechanism underpinning the relationship is identified as anomalous wind-driven mixing conditions associated with the NAO. In positive NAO phases, stronger westerly winds result in deeper mixed layers, delaying the start of the subpolar spring bloom by 2-3 weeks. The subpolar region also expands during positive phases, pushing the transition zone further south in the central North Atlantic. The magnitude of the bloom is found to be only weakly dependent on bloom timing, but is more strongly correlated with mixed layer depth. The extensive interannual variability in the timing of the bloom, particularly in the transition region, is expected to strongly impact the availability of food to higher trophic levels.
Henson, Stephanie A.; Dunne, John P.; Sarmiento, Jorge L.
Laboratory and field studies of the passive solid-phase adsorption toxin tracking (SPATT) method have been carried out around the world. A wide range of marine micro-algal toxins have been detected and the potential of the method to provide reliable, sensitive, time-integrated sampling to monitor the occurrence of toxic algal bloom events has been demonstrated. The method has several important advantages over current phytoplankton and shellfish monitoring methods. Trials of various adsorption substrates have been carried out and the best candidates have been selected for the lipophilic marine biotoxin groups; however, research continues to locate suitable substrates for the more polar water-soluble compounds such as domoic acid and the saxitoxins. The technique has also been successfully applied to the detection of a range of freshwater cyanobacterial toxins. PMID:20153627
MacKenzie, Lincoln A
A bloom of the dinoflagellate Scrippsiella trochoidea was detected for the first time in inner Tolo Harbor, Hong Kong in 2 000. Water samples were collected at eight stations along a transect passing through a red tide patch for microscopic analysis of phytoplankton composition and high-performance liquid chromatography (HPLC) analysis of phytoplankton pigments. During the bloom, the density of dinoflagellates was 1.1×106 cells L-1 within the patch and 8.6×105 cells L-1 outside the patch where the phytoplankton community was dominated by diatoms. After the bloom the S. trochoidea began to decrease in density and was replaced by diatoms as the dominating bloom-causing organisms at all stations, and the density of dinoflagellates at most stations was less than 1.0 × 106 cells L-1. The status of S. trochoidea as the causative species of the bloom was indicated by the presence of peridinin, the marker pigment for dinoflagellates. The shift from dinoflagellates to diatoms was marked by the decline of peridinin and the prevalence of fucoxanthin. Phytoplankton pigment markers also revealed the presence of other minor phytoplankton assemblages such as cryptomonads and blue-green algal.
Wong, Chun-Kwan; Wong, Chong-Kim
A bacterial-based bioremediation product, LakeRelief™ by Novozymes (Waterguru LakeRelief, 2011), was tested in a series of experiments between October 2008 and March 2009 to evaluate its suitability as a short-term intervention technique to reduce algal blooms in the Swan-Canning River system. Results from fibreglass tank experiments (1100 L) suggested that the product did not actively attack and lyse algal cells. The product decreased NH(4) and NO(x) concentrations in treated tanks, both aerated and non-aerated. Product application decreased PO(4) concentrations in non-aerated tanks but not in aerated tanks. The product appeared to suppress algal growth in non-aerated tanks over short periods (several days). Algal growth regularly diminished after product application but reappeared shortly afterwards. Aeration had a negative effect on bacterial proliferation in the tanks, possibly through alteration of environmental conditions (e.g. water mixing). As a consequence of the environmental conditions in the tanks being counterproductive to the development of a representative microbial composition, several aspects regarding the product's effectiveness could not be assessed satisfactorily in the tank experiments. The importance of long-term nutrient immobilisation into a well developed food web and the subsequent nutrient removal through removal of the top order organisms is highlighted. PMID:22386889
Schmack, M; Chambers, J; Dallas, S
The unexpected observation of 200 to 400 coliform bacteria per 100 ml in an unpolluted pristine stream was studied within Grand Teton National Park, Wyo. The high numbers of waterborne bacteria occurred in mid- to late summer at a location where there was a coincidental bloom of an algal mat community. Periphyton samplers were used to measure the algal growth that coincided with the increase in number of bacteria. Laboratory studies followed the growth of various coliform bacteria in the supernatant obtained from a Chlorella culture isolated from the mat community. Mixed natural bacterial populations from the stream and pure cultures of water-isolated fecal and nonfecal coliforms increased by two to three orders of magnitude at 13°C when grown in the algal supernatant. Radioactive algal products were obtained by feeding an axenic Chlorella culture 14C-labeled bicarbonate under laboratory cultivation at 13°C with illumination. Radioactive organic material from the algae became incorporated into the particulate fraction of pure cultures of coliform bacteria as they reproduced and was later released as they died.
McFeters, Gordon A.; Stuart, Sidney A.; Olson, Susan B.
Removal effects of cyanobcateria algal cells in chitosan-mediated in-situ-sediment in the sediment resuspension was studied in the laboratory. The research simulated the sediment suspension through quantitative simulated the middle-grade wave of lake Taihu, which usually experienced, by using the Y-type sediment resuspended generator. The results showed that the blue-green algal's removal effect is 93.55% and 99.19% as the dosage adding of chitosan and sediment were (0.100 + 0.200) g x L(-1) and (0.150 + 0.200) g x L(-1), respectively. The removal rate of turbidity of the water body reached 78.60% after still 30 min, in which the chitosan adding dosage was 0.150 g x L(-1); the removal rate of turbidity achieved 93.88% after 8 h of water body still. Furthermore, adding the chitosan could decrease the PO4(3-) -P concentration of water body in a short term. Preliminary results showed that the chitosan which adding dosage was 0.15 g x L(-1) could effectively remove the cyanobacteria cells in middle-grade wave situation; and also indicates using the chitosan-mediated sediment to flocculate the algal bloom of the Taihu Lake has a better application prospect. Contrast study shows that the quantitative simulation method of hydrodynamic intensity and the height of water has the obvious advantage to determine the dosage of chitosan in algal-flocculation removal. PMID:19353856
Liu, Guo-feng; Fan, Cheng-xin; Zhong, Ji-cheng; Bai, Xiu-ling; Yin, Hong-bin
We introduce the first algorithm that we are aware of to employ Bloom filters for Longest Prefix Matching (LPM). The algorithm performs parallel queries on Bloom filters, an efficient data structure for membership queries, in order to determine address prefix membership in sets of prefixes sorted by prefix length. We show that use of this algorithm for Internet Protocol (IP)
Sarang Dharmapurikar; Praveen Krishnamurthy; David E. Taylor
This article reviews Allan Bloom's 1987 book, THE CLOSING OF THE AMERICAN MIND: HOW HIGHER EDUCATION HAS FAILED DEMOCRACY AND IMPOVERISHED THE SOULS OF TODAY'S CHILDREN. Compares Bloom's book with THE HIGHER LEARNING IN AMERICA, a 1930s book by Mortimer Adler and Robert Hutchins. (JDH)
Cyanobacterial blooms, dominated by Microcystis sp. and associated microcystin variants, have been implicated in illnesses of humans and animals. Little is known regarding the formation of blooms and the presence of cyanotoxin variants in water bodies. Furthermore, the role played by ecological parameters, in regulating Microcystis blooms is complicate and diverse. Local authorities responsible for water management are often faced with the challenging task of dealing with cyanobacterial blooms. Therefore, the development of suitable monitoring approaches to characterize cyanobacterial blooms is an important goal. Currently, various biological, biochemical and physicochemical methods/approaches are being used to monitor cyanobacterial blooms and detect microcystins in freshwater bodies. Because these methods can vary as to the information they provide, no single approach seemed to be sufficient to accurately monitor blooms. For example, immunosensors are more suited for monitoring the presence of toxins in clear water bodies while molecular methods are more suited to detect potentially toxic strains. Thus, monitoring approaches should be tailored for specific water bodies using methods based on economic feasibility, speed, sensitivity and field applicability. This review critically evaluates monitoring approaches that are applicable to cyanobacterial blooms, especially those that focus on the presence of Microcystis, in freshwater bodies. Further, they were characterized and ranked according to their cost, speed, sensitivity and selectivity. Suggested improvements were offered as well as future research endeavors to accommodate anticipated environmental changes. PMID:23865979
Srivastava, Ankita; Singh, Shweta; Ahn, Chi-Yong; Oh, Hee-Mock; Asthana, Ravi Kumar
Certain rare human diseases with autosomal recessive mode of inheritance are associated with a greatly increased cancer frequency which may reflect specific defects in DNA repair or replication. These disorders include xeroderma pigmentosum, ataxia-telangiectasia, Fanconi's anaemia and Bloom's syndrome1. Cells from individuals with Bloom's syndrome2 usually grow slowly in culture and exhibit increased chromosomal breakage and rearrangement, an elevated frequency
Anne E. Willis; Tomas Lindahl
Biodiesel production using microalgae is attractive in a number of respects. Here a number of pros and cons to using microalgae for biofuels production are reviewed. Algal cultivation can be carried out using non-arable land and non-potable water with simple nutrient supply. In addition, algal biomass productivities are much higher than those of vascular plants and the extractable content of lipids that can be usefully converted to biodiesel, triacylglycerols (TAGs) can be much higher than that of the oil seeds now used for first generation biodiesel. On the other hand, practical, cost-effective production of biofuels from microalgae requires that a number of obstacles be overcome. These include the development of low-cost, effective growth systems, efficient and energy saving harvesting techniques, and methods for oil extraction and conversion that are environmentally benign and cost-effective. Promising recent advances in these areas are highlighted. PMID:23499181
Leite, Gustavo B; Abdelaziz, Ahmed E M; Hallenbeck, Patrick C
Interest in algae as a feedstock for biofuel production has risen in recent years, due to projections that algae can produce\\u000a lipids (oil) at a rate significantly higher than agriculture-based feedstocks. Current research and development of enclosed\\u000a photobioreactors for commercial-scale algal oil production is directed towards pushing the upper limit of productivity beyond\\u000a that of open ponds. So far, most
Kristina M. Weyer; Daniel R. Bush; Al Darzins; Bryan D. Willson
Microcystins were determined in 36 cyanobacterial (blue-green algal) bloom samples dominated by Microcystis aeruginosa, Aphanizomenon flos-aquae and Nostocspp. The analysed samples were collected from 8 water bodies in Poland during summers of 1996–2001. Ten microcystins (MC), three major and seven minor variants, were detected in natural cyanobacterial samples by high-performance liquid chromatography (HPLC). The structures of the microcystins were assigned
T. Jurczak; M. Tarczyñska; K. Karlsson; J. Meriluoto
Bacterial community structure on the surface of Ulva prolifera thalli and in seawater in an Ulva blooming region in Jiaozhou Bay was investigated by methods of denaturing gradient gel electrophoresis and 16S rDNA clone\\u000a libraries. Statistical analysis on the clone libraries indicated that bacterial community structure presented no significant\\u000a differences between two algal samples. Thallus-surface bacterial communities identified by 16S
Min Liu; Yi Dong; Yuan Zhao; Guangtao Zhang; Wuchang Zhang; Tian Xiao
Recent field work suggests an important ro^le for the Arctic Ocean in the global budget of dimethylsulphide (DMS), a climatically active volatile sulphur compound. Here, we have used an existing DMS production model and local field data to examine the temporal dynamics of the DMS cycle during the spring bloom in the Arctic shelf of the Barents Sea. The timing and duration of the spring phytoplankton bloom has been shown to be a key determinant of the flux of DMS to the atmosphere. Particular oceanic conditions due to the retreating ice-edge (e.g., a shallow mixed layer) can have an important effect on the timing of the phytoplankton bloom and thus the effux of DMS in this region. Model simulations support the view that algal taxonomy is not the most important factor determining DMS production in these waters. The mean vernal DMS flux is predicted to be 0.063mg S m2 d1 which is in general agreement with previous summer season averages in the Arctic.
Gabric, Albert J.; Matrai, Patricia A.; Vernet, María.
Bloom's Taxonomy has been utilized in many fields of studies. It has also been used in computer science education but research on the application of Bloom's Taxonomy into software engineering curricula has not been done much. This paper outlines software engineering assessment using Bloom's Taxonomy. Sample questions are given and categorized according to the relevant Bloom's Taxonomy levels. This paper
NURUL NASLIA KHAIRUDDIN; KHAIRUDDIN HASHIM
Algal biomass can provide viable third generation feedstock for liquid transportation fuel. However, for a mature commercial industry to develop, sustainability as well as technological and economic issues pertinent to algal biofuel sector must be addressed first. This viewpoint focuses on three integrated approaches laid out to meet these challenges. Firstly, an integrated algal biorefinery for sequential biomass processing for
Bobban G. Subhadra
A major goal of the U.S. Environmental Protection Agency's Biomonitoring research program is to produce test methods to assess environmental effects of anthropogenic activities in marine waters (Phelps et al., 1987). n support of EPA Region II involvement in the "Brown Tide Compr...
Internal loading of total phosphorus (TP) calculated from mass balance averaged 68±21% of the total (internal + external) summer loading in 14 of 17 western Washington lakes that had internal loading. Moreover, whole-lake mean TP for the 16 lakes with complete mass balance data was 50 ±9 ?g·L, which was similar to TP (51±18 ?g·L) predicted from summer internal P
Eugene B. Welch; Jean M. Jacoby
The local response of the phytoplankton community to river inflow processes was investigated with modeling and field analyses\\u000a in a long and narrow, stratified reservoir in mid-summer. The river water had high concentrations of phosphorus and nitrogen\\u000a (ammonium and nitrate) and temperature had large variations at diurnal scales. As a consequence of the large variation in\\u000a river temperature, the level
Javier Vidal; Rafael Marcé; Teresa Serra; Jordi Colomer; Francisco Rueda; Xavier Casamitjana
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
Peeter Ennet; Harri Kuosa; Rein Tamsalu
Mercury accumulation in fish is a global public health concern, because fish are the primary source of toxic methylmercury to humans. Fish from all lakes do not pose the same level of risk to consumers. One of the most intriguing patterns is that potentially dangerous mercury concentrations can be found in fish from clear, oligotrophic lakes whereas fish from greener,
Paul C. Pickhardt; Carol L. Folt; Celia Y. Chen; Bjoern Klaue; Joel D. Blum
With field culture experiments and model calculations, the natural-light-dependent growth and the optimal light layers in sea water for growth of red tide dinoflagellate Prorocentrum donghaiense Lu were studied in order to analyze the role of light on algal blooms in the coastal area in East China Sea in spring. The results show that the relationship of growth and light can be well described by Steele's equation, and the optimal light intensity (Iopt) of P. donghaiense is (38.2 +/- 3.8) W x m(-2), which is lower than Iopt for several other red tide algae (40-133 W x m(-2)), meaning that P. donghaiense may have an advantage when developing blooms in turbid environments where solar irradiance is easily attenuated. The optimal light layers for P. donghaiense growth are thicker offshore than inshore, and the thickness of optimal light layers in the subsurface water usually in 3-15 m in depth is about 5-10 m in the red tide area. The trade-off of light and nutrient fitness results in blooms in the so-called red tide area, and the light-optimum characteristic of the subsurface water is an important factor for the subsurface bloom development in spring. PMID:18613506
Sun, Bai-ye; Wang, Xiu-lin; Li, Yan-bin; Wang, Chang-you; Wang, Ai-jun; Liang, Sheng-kang; Zhang, Chuan-Song
Algal will turn abio-phosphate and ADP (Adenosine biphosphate) into ATP (Adenosine Triphosphate) for storing energy under enough sunlight. As environment conditions change, there will be a reversible process that ATP turns into ADP in order to release energy. Based on local monitoring data from representative valleys along the Three-Gorges valley during algae blooms, the activation energy deltaE of green alga photophosphorylation, the effective energy delta e and the integrated nutritional index TLI(sigma) in these water areas under different hydrological conditions are studied, and then the algae blooms evaluative Function F which has three parameters deltaE, delta e and TLI(sigma) has been constructed. Based on the impact degree of inner factors and environmental factors described above to algae blooms, correlative weight coefficient of deltaE, delta e and TLI(sigma) were introduced as a1 = 0.3, a2 = 0.3 and a3 = 0.4 respectively. Computing results and local monitoring data indicate that F is more reasonable, persuasible and generalizable than a single TLI(sigma) to predicate algae blooms or eutrophication in water environment. PMID:16767985
Liu, Xin-an; Zhan, Min; Xie, Zhao-min
An unusual phytoplankton bloom dominated by unidentified green coloured spherical algal cells (˜5?m diameter) and dinoflagellates ( Heterocapsa, Scripsiella and Gymnodinium) was encountered along the coast of Goa, India during 27 and 29 January, 2005. Pigment analysis was carried out using both fluorometric and HPLC methods. Seawater samples collected from various depths within the intense bloom area showed high concentrations of Chl a (up to 106 mg m - 3) associated with low bacterial production (0.31 to 0.52 mg C m - 3 h - 1) and mesozooplankton biomass (0.03 ml m - 3). Pigment analyses of the seawater samples were done using HPLC detected marker pigments corresponding to prasinophytes, dinoflagellates and diatoms. Chlorophyll b (36-56%) followed by peridinin (15-30%), prasinoxanthin (11-17%) and fucoxanthin (7-15%) were the major diagnostic pigments while pigments of cryptophytes and cyanobacteria including alloxanthin and zeaxanthin formed <10%. Although microscopic analysis indicated a decline in the bloom, pheaophytin concentrations in the water column measured by both techniques were very low, presumably due to fast recycling and/or settling rate. The unique composition of the bloom and its probable causes are discussed in this paper.
Bhaskar, P. V.; Roy, Rajdeep; Gauns, Mangesh; Shenoy, D. M.; Rao, V. D.; Mochemadkar, S.
This annotated Earth Science Picture of the Day shows a bloom of the phytoplankton E. huxleyi. Click on the image for a larger, more detailed version, or read text for an explanation of the organism and the phenomenon.
Gsfc, Nasa; Day, Earth S.
Snow algae are cold-tolerant algae growing on snow and ice and have been reported on glaciers in many parts of the world. Blooms of snow algae can reduce the surface albedo of snow and ice and significantly affect their melting. In addition, snow algae found in ice cores can be potential indicators of the paleo-environment, making them of great interest both to the biology and the geophysics of glaciers. A snow algal community was investigated in 2002 and 2003 on Akkem glacier in the Russian Altai mountains, where no information on its biological community has previously been available. Five species of snow algae including green algae and cyanobacteria were observed on the glacier. Red snow due to a bloom of algae (Chloromonas sp.) was visually apparent in the snow area during our study periods. The total algal cell-volume biomass on the glacier ranged from 97 to 1156 ?L m-2, which is equivalent to that reported previously on glaciers in the Himalaya and Alaska. The community structure showed that Mesotaenium berggrenii and/or Ancylonema nordenskioeldii, which are common species on glaciers in the Northern Hemisphere, were dominant in the ice area, while Chloromonas sp. was dominant in the snow area. Such community structures are similar to those on Alaskan and Arctic glaciers but differ from those on Himalayan and Tibetan glaciers, even though the Altai mountains are geographically closer to the Himalaya and Tibet than to Alaska. The difference in algal communities between the Altaic and other glaciers is discussed together with physical and chemical conditions affecting the algae.
Takeuchi, Nozomu; Uetake, Jun; Fujita, Koji; Aizen, Vladimir B.; Nikitin, Stanislav D.
The Arctic is highly sensitive to increasing global temperatures and is projected to experience dramatic ecological shifts in the next few decades. Oligosaline lakes are common in arctic regions where evaporation surpasses precipitation, however these extreme microbial communities are poorly characterized. Many oligosaline lakes, in contrast to freshwater ones, experience annual blooms of haptophyte algae that generate valuable alkenone biomarker records that can be used for paleoclimate reconstruction. These haptophyte algae are globally important, and globally distributed, aquatic phototrophs yet their presence in microbial molecular surveys is scarce. To target haptophytes in a molecular survey, we compared microbial community structure during two haptophyte bloom events in an arctic oligosaline lake, Lake BrayaSø in southwestern Greenland, using high-throughput pyrotag sequencing. Our comparison of two annual bloom events yielded surprisingly low taxon overlap, only 13% for bacterial and 26% for eukaryotic communities, which indicates significant annual variation in the underlying microbial populations. Both the bacterial and eukaryotic communities strongly resembled high-altitude and high latitude freshwater environments. In spite of high alkenone concentrations in the water column, and corresponding high haptophyte rRNA gene copy numbers, haptophyte pyrotag sequences were not the most abundant eukaryotic tag, suggesting that sequencing biases obscured relative abundance data. With over 170 haptophyte tag sequences, we observed only one haptophyte algal Operational Taxonomic Unit, a prerequisite for accurate paleoclimate reconstruction from the lake sediments. Our study is the first to examine microbial diversity in a Greenland lake using next generation sequencing and the first to target an extreme haptophyte bloom event. Our results provide a context for future explorations of aquatic ecology in the warming arctic.
Theroux, Susanna; Huang, Yongsong; Amaral-Zettler, Linda
To counter the negative effects of a product-harm crisis, brands hope to capitalize on their equity, and often use advertising\\u000a as a communication device to regain customers’ lost trust. We study how consumer characteristics and advertising influence\\u000a consumers’ first-purchase decisions for two affected brands of peanut butter following a severe Australian product-harm crisis.\\u000a Both pre-crisis loyalty and familiarity are found
Kathleen Cleeren; Marnik G. Dekimpe; Kristiaan Helsen
Aureococcus anophagefferens is a small pelagophyte that has caused harmful brown tide blooms in New York, New Jersey, Rhode Island, and Maryland. It is visually indistinguishable from other small algae in environ- mental samples using standard light microscopy, and current species-specific immunofluorescent counting techniques are not sensitive enough to detect concentrations lower than approximately 5000 cells mL -1 . A
Linda C. Popels; S. Craig Cary; David A. Hutchins; Rachel Forbes; Frances Pustizzi; Christopher J. Gobler; Kathryn J. Coyne
We developed the Blooming Biology Tool (BBT), an assessment tool based on Bloom's Taxon- omy, to assist science faculty in better aligning their assessments with their teaching activities and to help students enhance their study skills and metacognition. The work presented here shows how assessment tools, such as the BBT, can be used to guide and enhance teaching and student
Alison Crowe; Clarissa Dirks; Mary Pat Wenderoth
|We developed the Blooming Biology Tool (BBT), an assessment tool based on Bloom's Taxonomy, to assist science faculty in better aligning their assessments with their teaching activities and to help students enhance their study skills and metacognition. The work presented here shows how assessment tools, such as the BBT, can be used to guide and…
Crowe, Alison; Dirks, Clarissa; Wenderoth, Mary Pat
|This article offers a skeletal critique of the pedagogical theory and the teaching practices arising from the work of educational innovator, Benjamin Bloom. Professor Bloom's theory and method have overtly and covertly insinuated themselves into North American educational practice over the past half-century. Their impact and influence have been…
Doughty, Howard A.
We developed the Blooming Biology Tool (BBT), an assessment tool based on Bloom's Taxonomy, to assist science faculty in better aligning their assessments with their teaching activities and to help students enhance their study skills and metacognition. The work presented here shows how assessment tools, such as the BBT, can be used to guide and…
Crowe, Alison; Dirks, Clarissa; Wenderoth, Mary Pat
The carbon isotopic composition of the C37-alkenones has been used in various paleoceanographic studies to estimate the ancient surface water CO2 concentration [CO2aq]. A number of recent culture, field and sediment studies, however, indicate that the carbon isotopic fractionation in haptophyte algae is predominantly controlled by physiological processes and environmental factors other than the ambient [CO2aq]. The most prominent factors are algal growth rate, nutrient availability, light intensity, the carbon uptake mechanism (passive/active), and the carbon source (CO2aq/bicarbonate). To what extent these different factors might affect the carbon isotopic signal of alkenones ultimately preserved in the sediment is still under debate. A cause of uncertainty are the individual strenghts and weaknesses of the different methodological approaches. Culture experiments, for example, cannot perfectly recreate the sum of natural growth conditions and physical processes affecting the carbon isotopic signal in the field and its preservation in the sediment. On the other hand, core-top data represent several hundred to a couple of thousand years and therefore only reflect an average. Here, we present the first study testing the effects of [CO2aq] on the alkenone isotopic signal under natural bloom conditions in a semi-closed system. In a series of 9 floating mesocosms in a Norwegian fjord a bloom of Emiliania huxleyi was followed over a three week period. The mesocosms were covered by gas tight domes to adjust and maintain 3 different CO2 partial pressures in the tent atmosphere ranging from pre-industrial (190 ppmv) to year 2100 levels (680 ppmv) as predicted by the IPCC's report. We found that during the exponential growth phase the isotopic fractionation of alkenones decreased by 5 to 7 per mill and reached a plateau during the stationary phase. During the stationary phase the alkenone content per cell increased from 1-2 pg/cell to 6-8 pg/cell. Between the [CO2aq] treatments we observed an alkenone isotopic difference of only 2 per mill. These results indicate that changes in algal physiology and/or environmental conditions occuring during the course of an algal bloom strongly affect alkenone isotope fractionation. This effect overrides a comparatively small variation in the alkenone isotopic signal due to [CO2aq]. Implications for alkenone isotopic fractionation as a paleo-production or paleo-nutrient proxy will be discussed.
Benthien, A.; Zondervan, I.; Riebesell, U.; Engel, A.; Hefter, J.; Delille, B.; Harley, J.; Jacquet, S.
Deformed amphibians have been observed in eutrophic habitats, and some clues point to the retinoic acids (RAs) or RA mimics. However, RAs are generally thought of as vertebrate-specific hormones, and there was no evidence that RAs exist in cyanobacteria or algae blooms. By analyzing RAs and their analogs 4-oxo-RAs in natural cyanobacteria blooms and cultures of cyanobacteria and algae, we showed that cyanobacteria blooms could produce RAs, which were powerful animal teratogens. Intracellular RAs and 4-oxo-RAs with concentrations between 0.4 and 4.2 × 102 ng/L were detected in all bloom materials, and extracellular concentrations measured in water from Taihu Lake, China, were as great as 2.0 × 10 ng/L, which might pose a risk to wildlife through chronic exposure. Further examination of 39 cyanobacteria and algae species revealed that 32 species could produce RAs and 4-oxo-RAs (1.6–1.4 × 103 ng/g dry weight), and the dominant cyanobacteria species in Taihu Lake, Microcystis flos-aquae and Microcystis aeruginosa, produced high amounts of RAs and 4-oxo-RAs with concentrations of 1.4 × 103 and 3.7 × 102 ng/g dry weight, respectively. Most genera of cyanobacteria that could produce RAs and 4-oxo-RAs, such as Microcystis, Anabaena, and Aphanizomenon, often occur dominantly in blooms. Production of RAs and 4-oxo-RAs by cyanobacteria was associated with species, origin location, and growth stage. These results represent a conclusive demonstration of endogenous production of RAs in freshwater cyanobacteria blooms. The observation of teratogenic RAs in cyanobacteria is evolutionarily and ecologically significant because RAs are vertebrate-specific hormones, and cyanobacteria form extensive and highly visible blooms in many aquatic ecosystems.
Wu, Xiaoqin; Jiang, Jieqiong; Wan, Yi; Giesy, John P.; Hu, Jianying
Algal fuel sources promise unsurpassed yields in a carbon neutral manner that minimizes resource competition between agriculture and fuel crops. Many challenges must be addressed before algal biofuels can be accepted as a component of the fossil fuel replacement strategy. One significant challenge is that the cost of algal fuel production must become competitive with existing fuel alternatives. Algal biofuel production presents the opportunity to fine-tune microbial metabolic machinery for an optimal blend of biomass constituents and desired fuel molecules. Genome-scale model-driven algal metabolic design promises to facilitate both goals by directing the utilization of metabolites in the complex, interconnected metabolic networks to optimize production of the compounds of interest. Network analysis can direct microbial development efforts towards successful strategies and enable quantitative fine-tuning of the network for optimal product yields while maintaining the robustness of the production microbe. Metabolic modeling yields insights into microbial function, guides experiments by generating testable hypotheses, and enables the refinement of knowledge on the specific organism. While the application of such analytical approaches to algal systems is limited to date, metabolic network analysis can improve understanding of algal metabolic systems and play an important role in expediting the adoption of new biofuel technologies. PMID:20665641
Schmidt, Brian J; Lin-Schmidt, Xiefan; Chamberlin, Austin; Salehi-Ashtiani, Kourosh; Papin, Jason A
Cyanobacterial blooms represent a significant ecological and human health problem worldwide. In aquatic environments, cyanobacterial blooms are actually surrounded by dissolved organic matter (DOM) and attached organic matter (AOM) that bind with algal cells. In this study, DOM and AOM fractionated from blooming cyanobacteria in a eutrophic freshwater lake (Lake Taihu, China) were irradiated with a polychromatic UV lamp, and the photochemical heterogeneity was investigated using fluorescence excitation-emission matrix (EEM)-parallel factor (PARAFAC) analysis and synchronous fluorescence (SF)-two dimensional correlation spectroscopy (2DCOS). It was shown that a 6-day UV irradiation caused more pronounced mineralization for DOM than AOM (59.7% vs. 41.9%). The EEM-PARAFAC analysis identified one tyrosine-, one humic-, and two tryptophan-like components in both DOM and AOM, and high component photodegradation rates were observed for DOM versus AOM (k > 0.554 vs. <0.519). Moreover, SF-2DCOS found that the photodegradation of organic matters followed the sequence of tyrosine-like > humic-like > tryptophan-like substances. Humic-like substances promoted the indirect photochemical reactions, and were responsible for the higher photochemical rate for DOM. The lower photodegradation of AOM benefited the integrality of cells in cyanobacterial blooms against the negative impact of UV irradiation. Therefore, the photochemical behavior of organic matter was related to the adaptation of enhanced-duration cyanobacterial blooms in aquatic environments. PMID:24041526
Xu, Huacheng; Jiang, Helong
Progress in algal biofuels has been limited by significant knowledge gaps in algal biology, particularly as they relate to scale-up. To address this we are investigating how culture composition dynamics (light as well as biotic and abiotic stressors) describe key biochemical indicators of algal health: growth rate, photosynthetic electron transport, and lipid production. Our approach combines traditional algal physiology with
Jaclyn K. Murton; David T. Hanson; Tom Turner; Amy Jo Powell; Scott Carlton James; Jerilyn Ann Timlin; Steven Scholle; Andrew August; Brian P. Dwyer; Anne Ruffing; Howland D. T. Jones; James Bryce Ricken; Thomas A. Reichardt
We study the relation between advection by mesoscale eddies and jets and the remarkable eastward propagation of the Madagascar plankton bloom. Analyzing geostrophic velocity fields from altimetry with state-of-the-art Lagrangian techniques, we find fast coherent zonal jets in the recently discovered South Indian Ocean Countercurrent (SICC) at the exact position of the bloom. The coherent jets have a length of up to 1500km and provide a fast transport to the east. We use a new simple Lagrangian metric, the Finite-Time Zonal Drift (FTZD) to quantify the zonal transport and find that the jets can partly explain the explosive eastward propagation seen in the evolution of the Madagascar plankton bloom. Numerical experiments with a passive tracer concentration released at a known upwelling region south of Madagascar also supports the hypothesis that an important nutrient source of the plankton bloom could be located in that area. Until now, the reasons for the eastward propagation of the bloom's front remained totally unclear and even a propagation against the mean flow had been suggested. Moreover, we extract zonal jet-like Lagrangian Coherent Structures (LCS) from fields of the well-established Finite-Time Lyapunov Exponents (FTLE) that can be identified with barriers to meridional transport. Comparing these LCS with fields of chlorophyll concentration of the Madagascar plankton bloom measured by the Sea-viewing Wide Field-of view Sensor (SeaWiFS), we show that the location of jet-like LCS coincide with the boundaries of the plankton bloom, e.g. an LCS prevents cross-transport and confines the bloom to one side of the LCS. Phytoplankton is one of the few natural tracers that can be used to verify if the ubiquitous zonal mesoscale jets act as transport barriers. In the case of the Madagascar plankton bloom, we find clear evidence that the zonal jets in the SICC indeed represent transport barriers to the ambient flow and shape the northern boundary of the chlorophyll distribution. In other countercurrents, the Atlantic North Equatorial Countercurrent off Brazil and the Pacific North Equatorial Countercurrent off Indonesia, similar plankton patterns with sharp meandering boundaries appear which suggests that the results presented here might be valid more generally.
Huhn, F.; von Kameke, A.; Pérez-Muñuzuri, V.; Olascoaga, M. J.; Beronavera, F. B.
The late austral summer (February-April) phytoplankton bloom that occurs east of Madagascar exhibits significant interannual variability and at its largest extent covers ~1% of the world's ocean surface area. The bloom raises many intriguing questions about how it begins, is sustained, propagates to the east, exports carbon, and ends. It has been observed and studied using satellite ocean color observations, but the lack of in situ data makes it difficult to address these questions. Here we describe observations that were made serendipitously on a cruise in February 2005. These show clearly for the first time the simultaneous existence of a deep chlorophyll maximum at ~70-110 m depths (seen in SeaSoar fluorimeter data) and a surface chlorophyll signature [seen in Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite ocean color data]. The observations also show the modulation of the biological signature at the surface by the eddy field but not of the deep chlorophyll maximum. Trichodesmium dominates the bloom nearer to Madagascar, while the diatom Rhizosolenia clevei (and its symbiont Richelia intracellularis) dominates further from the island. The surface bloom seen in the SeaWiFS data is confined to the shallow (~30 m) mixed layer. It is hypothesized that the interannual variability in bloom intensity may be due to variations in coastal upwelling and thus the supply of iron, which is a micronutrient that can limit diazotroph growth.
Srokosz, M. A.; Quartly, G. D.
Sex work is an extremely dangerous profession. The use of harm-reduction principles can help to safeguard sex workers' lives in the same way that drug users have benefited from drug-use harm reduction. Sex workers are exposed to serious harms: drug use, disease, violence, discrimination, debt, criminalisation, and exploitation (child prostitution, trafficking for sex work, and exploitation of migrants). Successful and promising harm-reduction strategies are available: education, empowerment, prevention, care, occupational health and safety, decriminalisation of sex workers, and human-rights-based approaches. Successful interventions include peer education, training in condom-negotiating skills, safety tips for street-based sex workers, male and female condoms, the prevention-care synergy, occupational health and safety guidelines for brothels, self-help organisations, and community-based child protection networks. Straightforward and achievable steps are available to improve the day-to-day lives of sex workers while they continue to work. Conceptualising and debating sex-work harm reduction as a new paradigm can hasten this process. PMID:16360791
Rekart, Michael L
This website offers an explanation of red tide and other harmful algal blooms (HABs). It briefly explains what algal blooms are and what causes them. Designed for educatiors, the site also provides activity ideas and links to other HAB-related sites.
Boards, South A.
Accurate identification of cyanobacteria using traditional morphological taxonomy is challenging due to the magnitude of phenotypic plasticity among natural algal assemblages. In this study, molecular approach was utilized to facilitate the accurate identification of cyanobacteria in the Sacramento-San Joaquin Delta and in Clear Lake in Northern California where recurring blooms have been observed over the past decades. Algal samples were collected from both water bodies in 2011 and the samples containing diverse cyanobacteria as identified by morphological taxonomy were chosen for the molecular analysis. The 16S ribosomal RNA genes (16S rDNA) and the adjacent internal transcribed spacer (ITS) regions were amplified by PCR from the mixed algal samples using cyanobacteria generic primers. The obtained sequences were analyzed by similarity search (BLASTN) and phylogenetic analysis (16S rDNA) to differentiate species sharing significantly similar sequences. A total of 185 plasmid clones were obtained of which 77 were successfully identified to the species level: Aphanizomenon flos-aquae, Dolichospermum lemmermannii (taxonomic synonym: Anabaena lemmermannii), Limnoraphis robusta (taxonomic synonym: Lyngbya hieronymusii f. robusta) and Microcystis aeruginosa. To date, Dolichospermum and Limnoraphis found in Clear Lake have only been identified to the genus lavel by microscopy. During the course of this study, morphological identification and DNA barcoding confirmed A. flos-aquae as the predominant cyanobacterium in the Sacramento-San Joaquin Delta indicating a shift from M. aeruginosa that have dominated the blooms in the past decade. Lastly, the species-specific identification of Limnoraphis robusta in Clear Lake is another significant finding as this cyanobacterium has, thus far, only been reported in Lake Atitlan blooms in Guatemala. PMID:24133644
Kurobe, Tomofumi; Baxa, Dolores V; Mioni, Cécile E; Kudela, Raphael M; Smythe, Thomas R; Waller, Scott; Chapman, Andrew D; Teh, Swee J
Dense populations of the coccolithophore Pleurochrysis pseudoroscoffensis were found in surface films at several locations around the Salton Sea in Februarya??August, 1999. An unidentified coccolithophorid was also found in low densities in earlier studies of the lake (1955a??1956). To our knowledge, this is the first record of this widespread marine species in any lake. Samples taken from surface films typically contained high densities of one or two other phytoplankton species as well as high densities of the coccolithophore. Presence or absence of specific algal pigments was used to validate direct cell counts. In a preliminary screen using a brine shrimp lethality assay, samples showed moderate activity. Extracts were then submitted to a mouse bioassay, and no toxic activity was observed. These results indicate that blooms of P. pseudoroscoffensis are probably not toxic to vertebrates and do not contribute to the various mortality events of birds and fish that occur in the Salton Sea.
Reifel, K. M.; McCoy, M. P.; Tiffany, M. A.; Rocke, T. E.; Trees, C. C.; Barlow, S. B.; Faulkner, D.J.; Hurlbert, S.H.
Dense populations of the coccolithophore Pleurochrysis pseudoroscoffensis were found in surface films at several locations around the Salton Sea in February-August, 1999. An unidentified coccolithophorid was also found in low densities in earlier studies of the lake (1955-1956). To our knowledge, this is the first record of this widespread marine species in any lake. Samples taken from surface films typically contained high densities of one or two other phytoplankton species as well as high densities of the coccolithophore. Presence or absence of specific algal pigments was used to validate direct cell counts. In a preliminary screen using a brine shrimp lethality assay, samples showed moderate activity. Extracts were then submitted to a mouse bioassay, and no toxic activity was observed. These results indicate that blooms of P. pseudoroscoffensis are probably not toxic to vertebrates and do not contribute to the various mortality events of birds and fish that occur in the Salton Sea.
Reifel, K. M.; McCoy, M. P.; Tiffany, M. A.; Rocke, T. E.; Trees, C. C.; Barlow, S. B.; Faulkner, D. J.; Hurlbert, S. H.
Algal stromatolites (oncolites) occur on the insular shelves of the Canary Islands in the eastern Atlantic. Specimens from an unnamed bank in these islands are made up predominantly of the encrusting nullipore, Goniolithon accretum; vary in size between 0...
R. L. McMaster J. T. Conover
Considerable research and development is underway to produce fuels from microalgae, one of several options being explored for increasing transportation fuel supplies and mitigating greenhouse gas emissions (GHG). This work models life-cycle GHG and on-site freshwater consumption for algal biofuels over a wide technology space, spanning both near- and long-term options. The environmental performance of algal biofuel production can vary considerably and is influenced by engineering, biological, siting, and land-use considerations. We have examined these considerations for open pond systems, to identify variables that have a strong influence on GHG and freshwater consumption. We conclude that algal biofuels can yield GHG reductions relative to fossil and other biobased fuels with the use of appropriate technology options. Further, freshwater consumption for algal biofuels produced using saline pond systems can be comparable to that of petroleum-derived fuels. PMID:22324757
Vasudevan, Venkatesh; Stratton, Russell W; Pearlson, Matthew N; Jersey, Gilbert R; Beyene, Abraham G; Weissman, Joseph C; Rubino, Michele; Hileman, James I
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
Sophia I. Passy; Pierre Legendre
This research in progress includes the conceptual development of a model and metrics to determine and classify the level of cognition and added value included in selected knowledge management (KM) systems. Bloom’s Taxonomy of Cognitive Objectives and Greenwood’s Six C’s of the Knowledge Supply Chain will be analyzed in several enterprise and web applications. Bloom’s model uses six cognitive levels
Robert A. Rademacher
Blooms of cyanobacteria have appeared on the Potomac River near Washington, DC in years of drought and low river volume. The location of the bloom may be related to tidal activity. In 1983, the bloom of Microcystis aeruginosa used ammonia as its nitrogen source and contained low levels of toxic peptides. Cells collected from this bloom proved to be homogeneous and were an excellent source material for the isolation of proteins involved in photosynthesis.
Krogmann, David W.; Butalla, Ruth; Sprinkle, James
In this activity, students will use newly acquired knowledge of reading vector images of real-time Coastal Ocean Dynamics Application Radar (CODAR) data to predict the movement of a phytoplankton bloom off the coast of New Jersey. They will discover that plankton, the microscopic plants and animals floating in the ocean, are the base of the complex food webs that support life in the ocean, and for this reason scientists are interested in how and where blooms of plankton occur and how they move over time. They also learn that the location of plankton in the ocean is often associated with ocean currents.
Objective To study the nature of deliberate self-harm (DSH) in children and to identify the associated factors.\\u000a \\u000a \\u000a \\u000a Setting Child Guidance Clinic attached to the Department of Pediatrics of a teaching hospital in South India.\\u000a \\u000a \\u000a \\u000a Subjects Children with history of deliberate self harm who were referred to the CGC for psychological evaluation during a 10 year period.\\u000a \\u000a \\u000a \\u000a Methods Children and parents were interviewed together and
P. Krishnakumar; M. G. Geeta; A. Riyaz
In this paper we describe our use of the criterion-referenced approach to assessment, where the criteria are based upon Bloom's taxonomy. In our Bloom-based assessments scheme, all students in the class must satisfactorily complete a set of assessment tasks designed to demonstrate competence at the Knowledge and Comprehension levels of Bloom's taxonomy. Any student who is content with the minimal
The performance of microflotation, dispersed air flotation with microbubble clouds with bubble size about 50 µm, for algae separation using fluidic oscillation for microbubble generation is investigated. This fluidic oscillator converts continuous air supply into oscillatory flow with a regular frequency to generate bubbles of the scale of the exit pore. Bubble characterization results showed that average bubble size generated under oscillatory air flow state was 86 µm, approximately twice the size of the diffuser pore size of 38 µm. In contrast, continuous air flow at the same rate through the same diffusers yielded an average bubble size of 1,059 µm, 28 times larger than the pore size. Following microbubble generation, the separation of algal cells under fluidic oscillator generated microbubbles was investigated by varying metallic coagulant types, concentration and pH. Best performances were recorded at the highest coagulant dose (150 mg/L) applied under acidic conditions (pH 5). Amongst the three metallic coagulants studied, ferric chloride yielded the overall best result of 99.2% under the optimum conditions followed closely by ferric sulfate (98.1%) and aluminum sulfate with 95.2%. This compares well with conventional dissolved air flotation (DAF) benchmarks, but has a highly turbulent flow, whereas microflotation is laminar with several orders of magnitude lower energy density. PMID:22290221
Hanotu, James; Bandulasena, H C Hemaka; Zimmerman, William B
... to Women - Return from War - PTSD and Communities - PTSD Research - Mobile Apps - Páginas en Español - Videos - Web Links ... section of our website: Self-Harm and Trauma: Research Findings Date Created: See last Reviewed/Updated Date below. PTSD Site Map | Public Section | Professional Section | About Us: ...
Introduction: Self-harm is a direct, socially unacceptable, repetitive behavior that causes minor to moderate physical injury without suicidal intent. It is also a significant and growing concern among prison inmates, although it has been rarely studied. In the present study, we aimed to investigate demographic, psychosocial, and clinical variables associated to this critical bahaviour in a high risk sample of 1,555 male prisoners. Methods: Prisoners were interviewed about their history of self-mutilation, psychiatric history, and forensic history. The prisoners completed the Barratt Impulsivity Scale, Buss-Durkee Hostility Inventory, Eysenck Personality Questionnaire, and Childhood Trauma Questionnaire. Results: Eighteen percent of prisoners had a history of self-harm. They more frequently reported childhood traumas, were more likely to be unmarried, previously imprisoned, tested positive for substance abuse, had a history of suicide attempt, and more likely showed violent tendencies. Discussion: Self-harm among prisoners is common, being found in ~20% of the subjects in our sample. Self-mutilation among prisoners appears to be multi-factorial with developmental, socio-demographic, psychiatric, and personality determinants. Conclusion: Self-harm is associated with critical behaviors such as violence, substance abuse and suicide attempts, which represent major critical problems in contention environments. PMID:21450166
Carli, Vladimir; Mandelli, Laura; Poštuvan, Vita; Roy, Alec; Bevilacqua, Laura; Cesaro, Caterina; Baralla, Francesca; Marchetti, Marco; Serretti, Alessandro; Sarchiapone, Marco
When Edgster Dijkstra wrote his paper Go To Statements Considered Harmful, programmers were lost in millions of lines of spaghetti code. Now programmers have lost their way again---this time amidst thousands of unread resumes. Between 2000 and 2004, the percentage of incoming computer science freshmen fell by 60%. Drop rates of 30--50% are common. Results are similar for the other
Cyanobacteria produce many neurotoxins including beta-methylamino-L-alanine (BMAA) that has been liked to amyotrophic lateral sclerosis (ALS) and neurodegenerative disease. A number of ALS cases have been diagnosed among residents of Enfield, NH, a town encompassing a lake with a history of cyanobacteria algal blooms. To investigate an association between toxic cyanobacterial blooms in New Hampshire and development of ALS, we reviewed records from our institution and other community databases to obtain demographic information on patients diagnosed with ALS within New England. We identified nine ALS patients who lived near Lake Mascoma in Enfield, NH, an incidence of sporadic ALS that is 10 to 25 times the expected incidence of 2/100,000/year. We suggest that the high incidence of ALS in this potential cluster could be directly related to chronic exposure to cyanobacterial neurotoxins such as BMAA. Possible routes of toxin exposure include inhalation of aerosolized toxins, consuming fish, or ingestion of lake water. Further investigation, including analysis of brain tissue for cyanobacterial toxins, will be helpful to test for an association between BMAA and ALS. PMID:19929741
Caller, Tracie A; Doolin, James W; Haney, James F; Murby, Amanda J; West, Katherine G; Farrar, Hannah E; Ball, Andrea; Harris, Brent T; Stommel, Elijah W
Background Coral reefs degrade globally at an alarming rate, with benthic algae often replacing corals. However, the extent to which benthic algae contribute to coral mortality, and the potential mechanisms involved, remain disputed. Recent laboratory studies suggested that algae kill corals by inducing hypoxia on the coral surface, through stimulated microbial respiration. Methods/Findings We examined the main premise of this hypothesis by measuring in situ oxygen microenvironments at the contact interface between the massive coral Porites spp. and turf algae, and between Porites spp. and crustose coralline algae (CCA). Oxygen levels at the interface were similar to healthy coral tissue and ranged between 300–400 µM during the day. At night, the interface was hypoxic (?70 µM) in coral-turf interactions and close to anoxic (?2 µM) in coral-CCA interactions, but these values were not significantly different from healthy tissue. The diffusive boundary layer (DBL) was about three times thicker at the interface than above healthy tissue, due to a depression in the local topography. A numerical model, developed to analyze the oxygen profiles above the irregular interface, revealed strongly reduced net photosynthesis and dark respiration rates at the coral-algal interface compared to unaffected tissue during the day and at night, respectively. Conclusions/Significance Our results showed that hypoxia was not a consistent feature in the microenvironment of the coral-algal interface under in situ conditions. Therefore, hypoxia alone is unlikely to be the cause of coral mortality. Due to the modified topography, the interaction zone is distinguished by a thicker diffusive boundary layer, which limits the local metabolic activity and likely promotes accumulation of potentially harmful metabolic products (e.g., allelochemicals and protons). Our study highlights the importance of mass transfer phenomena and the need for direct in situ measurements of microenvironmental conditions in studies on coral stress.
Wangpraseurt, Daniel; Weber, Miriam; R?y, Hans; Polerecky, Lubos; de Beer, Dirk; Suharsono; Nugues, Maggy M.
Coastal waters support ~90 per cent of global fisheries and are therefore an important food reserve for our planet. Eutrophication of these waters, due to human activity, leads to severe oxygen depletion and the episodic occurrence of hydrogen sulphide-toxic to multi-cellular life-with disastrous consequences for coastal ecosytems. Here we show that an area of ~7,000km2 of African shelf, covered by sulphidic water, was detoxified by blooming bacteria that oxidized the biologically harmful sulphide to environmentally harmless colloidal sulphur and sulphate. Combined chemical analyses, stoichiometric modelling, isotopic incubations, comparative 16S ribosomal RNA, functional gene sequence analyses and fluorescence in situ hybridization indicate that the detoxification proceeded by chemolithotrophic oxidation of sulphide with nitrate and was mainly catalysed by two discrete populations of ?- and ?-proteobacteria. Chemolithotrophic bacteria, accounting for ~20 per cent of the bacterioplankton in sulphidic waters, created a buffer zone between the toxic sulphidic subsurface waters and the oxic surface waters, where fish and other nekton live. This is the first time that large-scale detoxification of sulphidic waters by chemolithotrophs has been observed in an open-ocean system. The data suggest that sulphide can be completely consumed by bacteria in the subsurface waters and, thus, can be overlooked by remote sensing or monitoring of shallow coastal waters. Consequently, sulphidic bottom waters on continental shelves may be more common than previously believed, and could therefore have an important but as yet neglected effect on benthic communities.
Lavik, Gaute; Stührmann, Torben; Brüchert, Volker; van der Plas, Anja; Mohrholz, Volker; Lam, Phyllis; Mußmann, Marc; Fuchs, Bernhard M.; Amann, Rudolf; Lass, Ulrich; Kuypers, Marcel M. M.
Phytoplankton productivity, standing stock, and related environmental factors were studied during 1964-66 in the Duwamish River estuary, at Seattle, Wash., to ascertain the factors that affect phytoplankton growth in the estuary; a knowledge of these factors in turn permits the detection and evaluation of the influence that effluent nutrients have on phytoplankton production. The factors that control the concentration of dissolved oxygen were also evaluated because of the importance of dissolved oxygen to the salmonid populations that migrate through the estuary. Phytoplankton blooms, primarily of diatoms, occurred in the lower estuary during August 1965 and 1966. No bloom occurred during 1964, but the presence of oxygen-supersaturated surface water in August 1963 indicates that a bloom did occur then. Nutrients probably were not the primary factor controlling the timing of phytoplankton blooms. Ammonia ,and phosphate concentrations increased significantly downstream from the Municipality of Metropolitan Seattle's Renton Treatment Plant outfall after the plant began operation in June 1965, and concentrations of nitrogen and phosphorus were relatively high before operation of the Renton Treatment Plant and during nonbloom periods. The consistent coincidence of blooms with minimum fresh-water discharge and tidal exchange during August throughout the study period indicates that bloom timing probably was controlled mostly by hydrographic factors that determine retention time and stability of the surface-water layer. This control was demonstrated in part by a highly significant correlation of gross productivity with retention time (as indicated by fresh-water discharge) and vertical stability (as indicated by the difference between mean surface and mean bottom temperatures). The failure of a bloom to develop in 1964 is related to a minimum fresh-water discharge that was much greater than normal during that summer. Hydrographic factors are apparently important because, as shown by studies of other estuarine environments by other workers, phytoplankton production increases when the zone of vertical turbulent mixing is not markedly deeper than the compensation depth. Phytoplankton cells produced in the surface waters sink, thereby contributing oxidizable organic matter to the bottom saline-water wedge. The maximum BOD (biochemical oxygen demand) in this bottom wedge occurs in the same section of the estuary and ,at the same time as the maximum phytoplankton biomass (as indicated by chlorophyll a) and minimum DO (dissolved oxygen). Other sources of BOD occur in the estuary, and conditions of minimum discharge and tidal exchange assist in reducing DO. Nonetheless, the highly significant correlation of chlorophyll a with BOD throughout the summer indicates that respiration and decomposition of phytoplankton cells is dearly an important contributor of BOD. Increases in the biomass and resultant B0D of blooms because of increased effluent nutrients presumably would further decrease the concentration of DO. This possible effect of effluent nutrients was evaluated by laboratory .bioassays and by a comparison of mean annual biomasses in the estuary. A green algal population in vitro did increase in response to added effluent nutrients; however, the available field data suggest that a 46-percent increase in effluent discharge between 1965 and 1966 did not increase the estuary's phytoplankton biomass significantly.
Welch, Eugene Brummer
Media from cultures of fibroblasts of six patients with the autosomal recessive disease Bloom syndrome (BS) and from four normal fibroblast strains were analyzed for clastogenic activity towards phytohemagglutinin-stimulated human blood lymphocytes from healthy donors. Clastogenic activity was detected in concentrated ultrafiltrates of media from all six BS strains but none of the normal fibroblast strains. The frequencies of chromosomal
Ingrid Emerit; Peter Cerutti
In an attempt to resolve conflicting conclusions arising from previous analyses, the LISREL method of J?reskog was applied to the data of Kropp and Stoker. It was found that the simplex assumption underlying Bloom's taxonomy is supported when the knowledge category is deleted from the taxonomy.
P. W. Hill; B. McGaw
Bloom's taxonomy attempts to provide a set of levels of cognitive engagement with material being learned. It is usually presented as a generic framework. In this paper we outline some studies which examine whether the taxonomy is appropriate for computing, and how its application in computing might differ from its application elsewhere. We place this in the context of ongoing
Colin G. Johnson; Ursula Fuller
Phytoplankton blooms are prominent features of biological variability in shallow coastal ecosystems such as estuaries, lagoons, bays, and tidal rivers. Long-term observation and research in San Francisco Bay illustrates some patterns of phytoplankton spatial and temporal variability and the underlying mechanisms of this variability. Blooms are events of rapid production and accumulation of phytoplankton biomass that are usually responses to changing physical forcings originating in the coastal ocean (e.g., tides), the atmosphere (wind), or on the land surface (precipitation and river runoff). These physical forcings have different timescales of variability, so algal blooms can be short-term episodic events, recurrent seasonal phenomena, or rare events associated with exceptional climatic or hydrologic conditions. The biogeochemical role of phytoplankton primary production is to transform and incorporate reactive inorganic elements into organic forms, and these transformations are rapid and lead to measurable geochemical change during blooms. Examples include the depletion of inorganic nutrients (N, P, Si), supersaturation of oxygen and removal of carbon dioxide, shifts in the isotopic composition of reactive elements (C, N), production of climatically active trace gases (methyl bromide, dimethylsulfide), changes in the chemical form and toxicity of trace metals (As, Cd, Ni, Zn), changes in the biochemical composition and reactivity of the suspended particulate matter, and synthesis of organic matter required for the reproduction and growth of heterotrophs, including bacteria, zooplankton, and benthic consumer animals. Some classes of phytoplankton play special roles in the cycling of elements or synthesis of specific organic molecules, but we have only rudimentary understanding of the forces that select for and promote blooms of these species. Mounting evidence suggests that the natural cycles of bloom variability are being altered on a global scale by human activities including the input of toxic contaminants and nutrients, manipulation of river flows, and translocation of species. This hypothesis will be a key component of our effort to understand global change at the land-sea interface. Pursuit of this hypothesis will require creative approaches for distinguishing natural and anthropogenic sources of phytoplankton population variability, as well as recognition that the modes of human disturbance of coastal bloom cycles operate interactively and cannot be studied as isolated processes.
Cloern, James E.
Ecological observations sustained over decades often reveal abrupt changes in biological communities that signal altered ecosystem states. We report a large shift in the biological communities of San Francisco Bay, first detected as increasing phytoplankton biomass and occurrences of new seasonal blooms that began in 1999. This phytoplankton increase is paradoxical because it occurred in an era of decreasing wastewater nutrient inputs and reduced nitrogen and phosphorus concentrations, contrary to the guiding paradigm that algal biomass in estuaries increases in proportion to nutrient inputs from their watersheds. Coincidental changes included sharp declines in the abundance of bivalve mollusks, the key phytoplankton consumers in this estuary, and record high abundances of several bivalve predators: Bay shrimp, English sole, and Dungeness crab. The phytoplankton increase is consistent with a trophic cascade resulting from heightened predation on bivalves and suppression of their filtration control on phytoplankton growth. These community changes in San Francisco Bay across three trophic levels followed a state change in the California Current System characterized by increased upwelling intensity, amplified primary production, and strengthened southerly flows. These diagnostic features of the East Pacific “cold phase” lead to strong recruitment and immigration of juvenile flatfish and crustaceans into estuaries where they feed and develop. This study, built from three decades of observation, reveals a previously unrecognized mechanism of ocean–estuary connectivity. Interdecadal oceanic regime changes can propagate into estuaries, altering their community structure and efficiency of transforming land-derived nutrients into algal biomass.
Cloern, James E.; Jassby, Alan D.; Thompson, Janet K.; Hieb, Kathryn A.
Ecological observations sustained over decades often reveal abrupt changes in biological communities that signal altered ecosystem states. We report a large shift in the biological communities of San Francisco Bay, first detected as increasing phytoplankton biomass and occurrences of new seasonal blooms that began in 1999. This phytoplankton increase is paradoxical because it occurred in an era of decreasing wastewater nutrient inputs and reduced nitrogen and phosphorus concentrations, contrary to the guiding paradigm that algal biomass in estuaries increases in proportion to nutrient inputs from their watersheds. Coincidental changes included sharp declines in the abundance of bivalve mollusks, the key phytoplankton consumers in this estuary, and record high abundances of several bivalve predators: Bay shrimp, English sole, and Dungeness crab. The phytoplankton increase is consistent with a trophic cascade resulting from heightened predation on bivalves and suppression of their filtration control on phytoplankton growth. These community changes in San Francisco Bay across three trophic levels followed a state change in the California Current System characterized by increased upwelling intensity, amplified primary production, and strengthened southerly flows. These diagnostic features of the East Pacific "cold phase" lead to strong recruitment and immigration of juvenile flatfish and crustaceans into estuaries where they feed and develop. This study, built from three decades of observation, reveals a previously unrecognized mechanism of ocean-estuary connectivity. Interdecadal oceanic regime changes can propagate into estuaries, altering their community structure and efficiency of transforming land-derived nutrients into algal biomass. PMID:18000053
Cloern, James E; Jassby, Alan D; Thompson, Janet K; Hieb, Kathryn A
Piedras Moras reservoir (32° 10'27" S and 64° 16' 29" W; 832 ha), integrates a series of artificial lakes belonging to the Rio Tercero basin (Córdoba, Argentina). During March 2009 an algal bloom occurred, coinciding with several animal species mortality, mainly wild birds. The goal of this work was to establish the trophic status of the reservoir in relation to that mortality. Variables were evaluated in situ (temperature and water transparency) and samples were taken in order to identify algal species, Chl-a concentration (spectrophotometry) and toxins - total microcystines- (inmuno-enzymatic assay, ELISA). Histopathology studies were made on Fulica sp. A strong heterogenity in water transparency was observed, and "patches" of Potamogeton berteroanus distributed all along the lake, with Secchi disk minimal and medium values of 0.15 and 0.94 m. Chl-a concentration oscillated from 35.7 to 320.9 mg.m-3. Predominant phytoplankton species were Anabaena spiroides and Microcystis aeruginosa (Cyanophyceae). Water temperature was 27.8 °C (±0.88). Maximal value of total microcystine concentration was 0.23 ?g.L-1. Chl-a concentration at the moment when mass mortality occurred (2.022 mg.m-3), and histopathological observations, strongly suggest that the animals' death was due to cianotoxins. PMID:21085789
Mancini, M; Rodriguez, C; Bagnis, G; Liendo, A; Prosperi, C; Bonansea, M; Tundisi, J G
Three jellyfish species, Aurelia aurita, Cyanea nozakii and Nemopilema nomurai, form large blooms in Chinese seas. We report on the distribution and increasing incidence of jellyfish blooms and their consequences in Chinese coastal seas and analyze their relationship to anthropogenically derived changes to the environment in order to determine the possible causes. A. aurita, C. nozakii and N. nomurai form blooms in the temperate Chinese seas including the northern East China Sea, Yellow Sea and Bohai Sea. N. nomurai forms offshore blooms while the other two species bloom mainly in inshore areas. Eutrophication, overfishing, habitat modification for aquaculture and climate change are all possible contributory factors facilitating plausible mechanisms for the proliferation of jellyfish blooms. In the absence of improvement in coastal marine ecosystem health, jellyfish blooms could be sustained and may even spread from the locations in which they now occur. PMID:20553695
Dong, Zhijun; Liu, Dongyan; Keesing, John K
Increasing eutrophication and algal bloom events in the Yangtze River Three Gorges Reservoir, China, are widely discussed with regard to changed hydrodynamics and nutrient transport and distribution processes. Insights into water exchange and interaction processes between water masses related to large-scale water level fluctuations in the reservoir are crucial to understand water quality and eutrophication dynamics. Therefore, confluence zones of tributaries with the Yangtze River main stream are dedicated key interfaces. In this study, water quality data were recorded in situ and on-line in varying depths with the MINIBAT towed underwater multi-sensor system in the confluence zone of the Daning River and the Yangtze River close to Wushan City during 1 week in August 2011. Geostatistical evaluation of the water quality data was performed, and results were compared to phosphorus contents of selective water samples. The strongly rising water level throughout the measurement period caused Yangtze River water masses to flow upstream into the tributary and supply their higher nutrient and particulate loads into the tributary water body. Rapid algal growth and sedimentation occurred immediately when hydrodynamic conditions in the confluence zone became more serene again. Consequently, water from the Yangtze River main stream can play a key role in providing nutrients to the algal bloom stricken water bodies of its tributaries. PMID:23247524
Holbach, Andreas; Wang, Lijing; Chen, Hao; Hu, Wei; Schleicher, Nina; Zheng, Binghui; Norra, Stefan
The carbon flux through major phytoplankton groups, defined by their pigment markers, was estimated in two contrasting conditions of the Northwestern Mediterranean open ocean ecosystem: the spring bloom and post-bloom situations (hereafter Bloom and Post-bloom, respectively). During Bloom, surface chlorophyll a (Chl a) concentration was higher and dominated by diatoms (53% of Chl a), while during Post-bloom Synechococcus (42%) and Prymnesiophyceae (29%) became dominant. The seawater dilution technique, coupled to high pressure liquid chromatography (HPLC) analysis of pigments and flow cytometry (FCM), was used to estimate growth and grazing rates of major phytoplankton groups in surface waters. Estimated growth rates were corrected for photoacclimation based on FCM-detected changes in red fluorescence per cell. Given the 30% average decrease in the pigment content per cell between the beginning and the end of the incubations, overlooking photoacclimation would have resulted in a 0.40 d -1 underestimation of phytoplankton growth rates. Corrected average growth rates ( ?o) were 0.90±0.20 (SD) and 0.40±0.14 d -1 for Bloom and Post-bloom phytoplankton, respectively. Diatoms, Cryptophyceae and Synechococcus were identified as fast-growing groups and Prymnesiophyceae and Prasinophyceae as slow-growing groups across Bloom and Post-bloom conditions. The higher growth rate during Bloom was due to dominance of phytoplankton groups with higher growth rates than those dominating in Post-bloom. Average grazing rates ( m) were 0.58±0.20 d -1 (SD) and 0.31±0.07 d -1. The proportion of phytoplankton growth consumed by microzooplankton grazing ( m/ ?o) tended to be lower in Bloom (0.69±0.34) than in Post-bloom (0.80±0.08). The intensity of nutrient limitation experienced by phytoplankton indicated by ?o/ ?n (where ?n is the nutrient-amended growth rate), was similar during Bloom (0.78) and Post-bloom (0.73). Primary production from surface water (PP) was estimated with 14C incubations. A combination of PP and Chl a synthesis rate yielded C/Chl a ratios of 34±21 and 168±75 (g:g) for Bloom and Post-bloom, respectively. Transformation of group-specific Chl a fluxes into carbon equivalents confirmed the dominant role of diatoms during Bloom and Synechococcus and Prymnesiophyceae during Post-bloom.
Gutiérrez-Rodríguez, Andrés; Latasa, Mikel; Estrada, Marta; Vidal, Montserrat; Marrasé, Celia
The current anti-doping policy ('war on doping') resembles the 'war on drugs' in several aspects, including a zero-tolerance approach, ideology encroaching on human rights and public health principles, high cost using public money for repression and control, and attempts to shape internationally harmonized legal frameworks to attain its aim. Furthermore, even if for different reasons, both wars seem not to be able to attain their objectives, and possibly lead to more harm to society than they can prevent.The Olympic buzz is mounting and we can expect multiple headlines in the media on doping and anti-doping stories related to this event. In this article we describe current anti-doping policy, reflect on its multiple unplanned consequences, and end with a discussion, if lessons learned from harm reduction experiences in the illicit drugs field could be applied to anti-doping. PMID:22788912
Kayser, Bengt; Broers, Barbara
The current anti-doping policy (‘war on doping’) resembles the ‘war on drugs’ in several aspects, including a zero-tolerance approach, ideology encroaching on human rights and public health principles, high cost using public money for repression and control, and attempts to shape internationally harmonized legal frameworks to attain its aim. Furthermore, even if for different reasons, both wars seem not to be able to attain their objectives, and possibly lead to more harm to society than they can prevent. The Olympic buzz is mounting and we can expect multiple headlines in the media on doping and anti-doping stories related to this event. In this article we describe current anti-doping policy, reflect on its multiple unplanned consequences, and end with a discussion, if lessons learned from harm reduction experiences in the illicit drugs field could be applied to anti-doping.
Blooms of the potentially toxic cyanobacterium Microcystis are common events globally, and as a result significant resources continue to be dedicated to monitoring and controlling these events. Recent studies have shown that a significant proportion of total cell-associated phosphorus (P) in marine phytoplankton can be surface adsorbed; as a result studies completed to date do not accurately report the P demands of these organisms. In this study we measure the total cell-associated and intracellular P as well as growth rates of two toxic strains of Microcystis aeruginosa Kütz grown under a range of P concentrations. The results show that the intracellular P pool in Microcystis represents a percentage of total cell-associated P (50–90%) similar to what has been reported for actively growing algae in marine systems. Intracellular P concentrations (39–147?fg?cell?1) generally increased with increasing P concentrations in the growth medium, but growth rate and the ratio of total cell-associated to intracellular P remained generally stable. Intracellular P quotas and growth rates in cells grown under the different P treatments illustrate the ability of this organism to successfully respond to changes in ambient P loads, and thus have implications for ecosystem scale productivity models employing P concentrations to predict algal bloom events.
Saxton, Matthew A.; Arnold, Robert J.; Bourbonniere, Richard A.; McKay, Robert Michael L.; Wilhelm, Steven W.
This page explains some of the harmful effects of acid rain on people, forests, lakes and streams, and infrastructure (buildings, monuments). Topics include ground-level ozone and respiratory diseases in people, removal of nutrients from soil and plant leaves or needles, acidification and release of aluminum into lakes and streams, and corrosion of stone and metal in buildings and monuments. Links to a glossary are embedded in the text.
Protein-rich bloom algae biomass was employed as nitrogen source in fuel ethanol fermentation using high gravity sweet potato medium containing 210.0 g l(-1) glucose. In batch mode, the fermentation could not accomplish even in 120 h without any feeding of nitrogen source. While, the feeding of acid-hydrolyzed bloom algae powder (AHBAP) notably promoted fermentation process but untreated bloom algae powder (UBAP) was less effective than AHBAP. The fermentation times were reduced to 96, 72, and 72 h if 5.0, 10.0, and 20.0 g l(-1) AHBAP were added into medium, respectively, and the ethanol yields and productivities increased with increasing amount of feeding AHBAP. The continuous fermentations were performed in a three-stage reactor system. Final concentrations of ethanol up to 103.2 and 104.3 g l(-1) with 4.4 and 5.3 g l(-1) residual glucose were obtained using the previously mentioned medium feeding with 20.0 and 30.0 g l(-1) AHBAP, at dilution rate of 0.02 h(-1). Notably, only 78.5 g l(-1) ethanol and 41.6 g l(-1) residual glucose were obtained in the comparative test without any nitrogen source feeding. Amino acids analysis showed that approximately 67% of the protein in the algal biomass was hydrolyzed and released into the medium, serving as the available nitrogen nutrition for yeast growth and metabolism. Both batch and continuous fermentations showed similar fermentation parameters when 20.0 and 30.0 g l(-1) AHBAP were fed, indicating that the level of available nitrogen in the medium should be limited, and an algal nitrogen source feeding amount higher than 20.0 g l(-1) did not further improve the fermentation performance. PMID:22387426
Shen, Yu; Guo, Jin-Song; Chen, You-Peng; Zhang, Hai-Dong; Zheng, Xu-Xu; Zhang, Xian-Ming; Bai, Feng-Wu
By the examination of the interaction between nitrogen and phosphorus species relative to algal growth in several fresh water environments of differing trophic state, it has been possible to establish the relative significance of these elements as algal n...
C. M. Weiss
The goal of nursing care is to promote health and reduce harm caused by injury, disease, or poor self-care. Harm reduction is a public health model, which is gaining popularity as an effective modality to help persons reduce the negative consequences associated with their drug use. The harm reduction model blends well with the core principles of nursing. When viewed
Mary Lynn Mathre
Diverse lines of evidence point to a basic human aversion to physically harming others. First, we demonstrate that unwillingness to endorse harm in a moral dilemma is predicted by individual differences in aversive reactivity, as indexed by peripheral vasoconstriction. Next, we tested the specific factors that elicit the aversive response to harm. Participants performed actions such as discharging a fake
Fiery Cushman; Kurt Gray; Allison Gaffey; Wendy Berry Mendes
Genotoxic, genetic and behavioral impacts of the paralytic shellfish toxin (PST)-producing alga Alexandrium minutum on the oyster Crassostrea gigas were assessed using RAPD-PCR, qPCR and valve activity recording. Oysters were exposed to a dose mimicking an algal bloom (?1600cellsml(-1)) for 48h. Results indicate a rapid and sustained behavioral disturbance. Animals remained open but exhibited reduced valve-opening amplitude, correlated to the amount of toxin accumulated in the digestive gland. They also exhibited increased micro-closures. In the gills, gene transcription levels were modified: a transcriptional repression of genes involved in oxidative and mitochondrial metabolism, endogenous clock, immunity and detoxification processes was observed. DNA impacts, both quantitative and qualitative, were observed as well. Indeed, both the PCR product profile and the number of hybridization sites for the RAPD probe OPB7 were modified. These results indicate genotoxic effects and gene repression in C. gigas following behavioral disturbance by A. minutum. PMID:23933679
Mat, Audrey M; Haberkorn, Hansy; Bourdineaud, Jean-Paul; Massabuau, Jean-Charles; Tran, Damien
The systems level codes used to model high energy laser (HEL) propagation for potential military applications do not account for losses of laser energy due to droplet evaporation. As a consequence, these evaporative effects represent a net reduction in the amount of overlap thermal blooming. An algorithm we developed to fill this void and its implementation into the U.S. Army's systems level propagation code, BRLPRO, will be discussed. Our approach modifies the phase integral computations of BRLPRO to include the effects on N phosphoric smoke clouds along the propagation path. The key component of this algorithm is the FRACTION model which determines the fraction of the smoke aerosol absorption within a smoke cloud which is effective in heating the atmosphere and causing thermal blooming. FRACTION methodology provides a first-principle calculation of the time-averaged thermodynamics which describe the vaporization resulting from the interaction of laser radiation with hygroscopic smoke particles.
Oconnor, R. E.; Harper, R. C.; Reynolds, R. W.
Plankton play an important role in the ecology of the ocean and the climate because of their participation in the global carbon cycle at the base of the food chain. However, damaging plankton blooms can sometimes occur and are initially characterized by sudden transient increases in the phytoplankton population. They are thought to be driven by several effects, such as seasonal variations in temperature and salinity, and nutrient mixing. Furthermore, phytoplankton and zooplankton have different buoyancy properties, leading to a differential response in turbulent environments. In this paper, we investigate this effect in a model of advected plankton dynamics. We find that, over a range of parameter values, flows of marine species subjected to inertial/viscous forces naturally lead to patchiness and, in turn, periodically sustained plankton blooms.
Reigada, R; Hillary, R M; Bees, M A; Sancho, J M; Sagues, F
While research and development of algal biofuels are currently receiving much interest and funding, they are still not commercially viable at today’s fossil fuel prices. However, a niche opportunity may exist where algae are grown as a by-product of high rate algal ponds (HRAPs) operated for wastewater treatment. In addition to significantly better economics, algal biofuel production from wastewater treatment
J. B. K. Park; R. J. Craggs; A. N. Shilton
Abstract Invasive bloomsof the siphonaceous greenalgae Codiumspp. have been considered a symptom ofcoastal eutrophicationbut, to date, only limitedbiochemical evidence supports a linkage to land-based nutrient pollution. Beginningin the summer of 1990, spectacular blooms,of unattached Codium isthmocladum,developed on deep coral reef habitats in southern Palm Beach County and northern Broward County, and in subsequent years, attached populations formed on reefs in
Brian E. Lapointe; Peter J. Barile; Mark M. Littler; Diane S. Littler; Bradley J. Bedford; Constance Gasque
ORD/NATIONAL HEALTH EFFECTS AND ENVIRONMENTAL RESEARCH LABORATORY RESEARCH AREA: CLEAN WATER: AQUATIC STRESSORS--DEVELOP STRESSOR-RESPONSE MODELS FOR NUTRIENTS, INCLUDING EUTROPHICATION, HYPOXIA, ETC.
This research will determine the nature and extent of the risk associated with eutrophication, hypoxia and harmful algal blooms. Stressor response models will be developed to understand and predict the relationship between stressors such as nutrients (including nitrogen), eutroph...
This study examines self-harm in a community sample of adolescents. More specifically, the study identifies the prevalence and types of self-harm, elucidates the nature and underlying function of self-harm, and evaluates the relation of psychological adjustment, sociodemographic, and health-risk variables to self-harm. Self-report questionnaires…
Laye-Gindhu, Aviva; Schonert-Reichl, Kimberly A.
Concentrations of phosphorus, nitrate, ammonia, oxygen, chlorophyll a, and rates of algal photosynthesis in 5 lakes in Fairmont, Minnesota, were measured during spring, summer, and autumn, 1972. The relative abundance of the planktonic algae in the lakes ...
A. S. Knoll R. O. Megard
After a 20-year absence, severe cyanobacterial blooms have returned to Lake Erie in the last decade, in spite of negligible change in the annual load of total phosphorus (TP). Medium-spectral Resolution Imaging Spectrometer (MERIS) imagery was used to quantify intensity of the cyanobacterial bloom for each year from 2002 to 2011. The blooms peaked in August or later, yet correlate to discharge (Q) and TP loads only for March through June. The influence of the spring TP load appears to have started in the late 1990 s, after Dreissenid mussels colonized the lake, as hindcasts prior to 1998 are inconsistent with the observed blooms. The total spring Q or TP load appears sufficient to predict bloom magnitude, permitting a seasonal forecast prior to the start of the bloom. PMID:22870327
Stumpf, Richard P; Wynne, Timothy T; Baker, David B; Fahnenstiel, Gary L