Showing papers by "National Ocean Service published in 1999"
TL;DR: The authors' detection of P. australis frustules, via scanning electron microscopy, in both anchovy viscera and fecal material from sea lions exhibiting seizures provides corroborating evidence that this toxic algal species was involved in this unusual sea lion mortality event.
Abstract: The occurrence of an unusual mortality event involving California sea lions (Zalophus californianus) along the central California coast in May 1998 was recently reported. The potent neurotoxin domoic acid (DA), produced naturally by the diatom Pseudo-nitzschia australis and transmitted to the sea lions via planktivorous northern anchovies (Engraulis mordax), was identified as the probable causative agent. Details of DA analyses for anchovy tissues and sea lion feces are described. Domoic acid levels were estimated in anchovy samples by HPLC-UV, and in sea lion feces using the same method as well as a microplate receptor binding assay, with absolute confirmation by tandem mass spectrometry. The highest DA concentrations in anchovies occurred in the viscera (223 +/- 5 microg DA g(-1)), exceeding values in the body tissues by seven-fold and suggesting minimal bioaccumulation of DA in anchovy tissue. HPLC values for DA in sea lion fecal material (ranging from 152 to 136.5 microg DA g(-1)) required correction for interference from an unidentified compound. Inter-laboratory comparisons of HPLC data showed close quantitative agreement. Fecal DA activity determined using the receptor binding assay corresponded with HPLC values to within a factor of two. Finally, our detection of P. australis frustules, via scanning electron microscopy, in both anchovy viscera and fecal material from sea lions exhibiting seizures provides corroborating evidence that this toxic algal species was involved in this unusual sea lion mortality event.
214 citations
TL;DR: Whether algicidal bacteria active against Gymnodinium breve Davis, a dinoflagellate responsible for frequent and protracted red tides in the Gulf of Mexico, are present in the waters of the west Florida shelf is determined and a conceptual model for interactions between alg suicidal bacteria and their target species is proposed to serve as a testable framework for ensuing field studies.
Abstract: Interactions between bacteria and species of harmful and/or toxic algae are potentially important factors affecting both the population dynamics and the toxicity of these algae. Recent reports of bacteria lethal to certain harmful algal bloom (HAB) species, coupled with a rapidly evolving interest in attempting to minimize the adverse effects of HABs through various prevention, control, and mitigation strategies, have focused attention on defining the role of algicidal bacteria in bloom termination. The aim of the present study was to determine whether algicidal bacteria active against Gymnodinium breve Davis, a dinoflagellate responsible for frequent and protracted red tides in the Gulf of Mexico, are present in the waters of the west Florida shelf. To date, we have isolated two bacterial strains from this region lethal to G. breve and have begun to characterize the algicidal activity of one of these strains, 41-DBG2. This bacterium, a yellow-pigmented, gram-negative rod, was isolated from waters containing no detectable G. breve cells, suggesting that such bacteria are part of the ambient microbial community and are not restricted to areas of high G. breve abundance. Strain 41-DBG2 produced a dissolved algicidal compound(s) that was released into the growth medium, and the algicide was effective against the four Gulf of Mexico G. breve isolates tested as well as a closely related HAB species that also occurs in this region, Gymnodinium mikimotoi Miyake et Kominami ex Oda. Nonetheless, data showing that a nontoxic isolate of Gymnodinium sanguineum Hirasaka from Florida Bay was not affected indicate that the algicidal activity of this bacterium does exhibit a degree of taxonomic specificity. Our efforts are currently being directed at resolving several critical issues, including the identity of the algicide(s), the mechanisms regulating its production and ability to discriminate between target algal species, and how the growth rate of 41-DBG2 is affected by the presence of G. breve cells. We have also proposed a conceptual model for interactions between algicidal bacteria and their target species to serve as a testable framework for ensuing field studies.
160 citations
TL;DR: Collectively, the rRNA probe and toxin analyses suggest that manifestation of DA in the environment is possible in the absence of readily recognizable intact cells.
Abstract: Large-subunit ribosomal RNA-targeted probes for Pseudo-nitzschia australis Frenguelli, P. multiseries (Hasle) Hasle, P. pseudodelicatissima (Hasle) Hasle, and P. pungens (Grunow) Hasle were applied to cultured and natural samples using whole-cell and sandwich hybridization. Testing of the latter method is emphasized here, and technique refinements that took place during 1996–1997 are documented. Application of the sandwich hybridization test showed that the signal intensity obtained for a given number of target cells remained constant as batch cultures of these organisms progressed from active through stationary growth phases. This suggests that cellular rRNA content for each target species remained relatively stable despite changes in growth state. Application of whole-cell and sandwich hybridization assays to natural samples showed that both methods could be used to detect wild P. australis, P. pseudodelicatissima, and to a lesser degree P. multiseries, but detection of P. pungens was prone to error. A receptor-binding assay for domoic acid (DA) enabled detection of this toxin activity associated with a particulate fraction of the plankton and provided a context in which to view results of the rRNA probe tests. In one case, the probe for P. australis cross-reacted with P. cf. delicatissima. The sample that contained the latter species also contained a low amount of DA activity. Under certain field conditions, results of whole-cell and sandwich hybridization tests disagreed. Detailed analysis of selected field samples illustrates how such situations arose. Collectively, the rRNA probe and toxin analyses suggest that manifestation of DA in the environment is possible in the absence of readily recognizable intact cells.
123 citations
TL;DR: Overall, larval transport was determined by circulation but was modified by larval vertical distributions, which demonstrated the importance of along-shelf transport in what is generally thought to be a ‘cross- shelf’ problem.
Abstract: A three-dimensional circulation model was used in conjunction with larval fish vertical behaviour models to study the interaction between larval vertical distribution, advection and the outcome of larval transport along the central portion of the east coast of the United States. The circulation model was forced by tides, a northern boundary inflow, and winds. Vertical behaviour models were developed for Atlantic menhaden (Brevoortia tyrannus) and spot (Leiostomus xanthurus). The purpose of this modelling effort was to investigate the transport pathways of Atlantic menhaden and spot larvae from offshore spawning grounds to estuarine nursery habitats. The coupled circulation and behavioural model demonstrated the importance of along-shelf transport in what is generally thought to be a ‘cross-shelf’ problem. Cross-shelf transport was associated with bathymetric features, such as shoals. Both physical (e.g. wind) and biological (e.g. changes in larval behaviour) events were responsible for many of the observed patterns in larval transport. Overall, larval transport was determined by circulation but was modified by larval vertical distributions.
102 citations
TL;DR: An 18‐month field survey of the Pseudo‐nitzschia population present in Louisiana coastal waters was conducted comparing species abundance estimates by novel fluorescent molecular probes with traditional electron and differential‐interference light microscopy, finding discrepancies appear to be because of genetic variation within the pseudodelicatissima population.
Abstract: An 18-month field survey of the Pseudo-nitzschia population present in Louisiana coastal waters was conducted comparing species abundance estimates by novel fluorescent molecular probes (16S large subunit rDNA oligonucleotide sequences) with traditional electron and differential-interference light microscopy While the probe and microscopic analyses agreed on the presence or absence of four common Pseudo-nitzschia species (P multiseries (Hasle) Hasle, P pseudodelicatissima (Hasle) Hasle, P delicatissima (PT Cleve) Heiden, and P pungens (Grunow) Hasle in 66% of the samples analyzed, the probes gave conflicting results with the microscopic methods in the remaining 34% of the samples The majority of the discrepancies appear to be because of genetic variation within the Pseudo-nitzschia population, especially in P pseudodelicatissima, indicating that the Monterey Bay Pseudo-nitzschia spp may not be appropriate reference strains for distinguishing Louisiana Pseudo-nitzschia spp Additionally, P pseudodelicatissima has been associated with domoic acid (DA) activity in three field samples, at levels up to 22 times higher than the highest value given inother published reports of DA production by this species The contemporaneous existence of multiple strains of P pseudodelicatissima (toxic and non-toxic) presents new challenges to the study of the ecophysiology and population dynamics of this bloom-forming species
100 citations
TL;DR: Diel phasing of the cell‐cycle in the Florida red tide dinoflagellate Gymnodinium breve Davis is described, the diel cue which serves to entrain the cell-cycle is determined, and evidence for the presence of cyclin‐dependent kinase (CDK), a cell‐ cycle regulator which may be responsive to this cue is provided.
Abstract: The diel cycle is a key regulator of the cell-cycle in many dinoflagellates, but the mechanisms by which the diel cycle entrains the cell-cycle remain poorly understood. In this study, we describe diel phasing of the cell-cycle in the Florida red tide dinoflagellate Gymnodinium breve Davis, determine the diel cue which serves to entrain the cell-cycle, and provide evidence for the presence of cyclin-dependent kinase (CDK), a cell-cycle regulator which may be responsive to this cue. Four laboratory isolates from the West Coast of Florida were compared. When grown on a 16:8 h LD cycle, all isolates displayed phased cell division, with the S-phase beginning 6–8 h into the light phase, and mitosis following 12–14 h later, as determined by flow cytometry. A naturally occurring bloom of G. breve, studied over one diel cycle, displayed diel cell-cycle phasing similar to that in the laboratory cultures, with the S-phase beginning during daylight and the peak of mitosis occurring approximately 4 h after sunset. In the laboratory cultures, the dark/light “dawn” transition was found to provide the diel cue which serves to entrain the G. breve cell-cycle, whereas the light/ dark “dusk” transition did not appear to be involved. Evidence for the presence of CDK in G. breve was obtained using two approaches: (1) identification of a 34-kDa protein, immunoreactive to an antibody against a conserved amino acid sequence (α-PSTAIR) unique to the CDK protein family and (2) inhibition of the cell-cycle by olomoucine, a selective CDK inhibitor. Together, these results provide the basis from which one can begin addressing mechanisms by which the diel cycle regulates the cell-cycle in G. breve.
66 citations
TL;DR: The reporter gene assay detected activity in toxic isolates of P. piscicida from several North Carolina estuaries in 1997 and 1998 and may also be suitable for detecting toxic activity in human and animal serum.
Abstract: Collaborative studies were performed to develop a functional assay for fish-killing activity produced by Pfiesteria piscicida. Eight cell lines were used to screen organic fractions and residual wa...
62 citations
TL;DR: The sensitivity of embryonic fish to direct oocyte exposure indicates that maternal transfer of low levels of ciguatoxin may represent an unrecognized threat to the reproductive success of reef fish and a previously undetected ecological consequence of proliferation of cigUatoxin-producing algae in reef systems increasingly impacted by human perturbations.
50 citations
TL;DR: It is shown that domoic acid-treated animals were incapable of forming a memory that persisted for 24 h and hence were less able to utilize the prior day's experience, and the repeated exposure groups did not perform as poorly on non-alternation days than the single exposure groups, indicating that domeic acid may affect multiple mechanisms involved in memory consolidation.
48 citations
TL;DR: A dramatic increase in assay efficiency is reported through application of microplate scintillation technology, resulting in an assay turn around time of 4 h, and this assay should be effective as a screening tool for use by public health officials in responding to suspected cases of PSP intoxication.
Abstract: We recently described a high throughput receptor binding assay for paralytic shellfish poisoning (PSP) toxins, the use of the assay for detecting toxic activity in shellfish and algal extracts, and the validation of 11-[3H]-tetrodotoxin as an alternative radioligand to the [3H]-saxitoxin conventionally employed in the assay. Here, we report a dramatic increase in assay efficiency through application of microplate scintillation technology, resulting in an assay turn around time of 4 h. Efforts are now focused on demonstrating the range of applications for which this receptor assay can provide data comparable to the more time consuming, technically demanding HPLC analysis of PSP toxins, currently the method of choice for researchers. To date, we have compared the results of both methods for a variety of sample types, including different genera of PSP toxin producing dinoflagellates (e.g. Alexandrium lusitanicum, r2 = 0.9834, n = 12), size-fractioned field samples of Alexandrium spp. (20-64 microm; r2 = 0.9997, n = 10) as well as its associated zooplankton grazer community (200-500 microm: r2 = 0.6169, n = 10; >500 microm: r2 = 0.5063, n = 10), and contaminated human fluids (r2 = 0.9661, n = 7) from a PSP outbreak. Receptor-based STX equivalent values for all but the zooplankton samples were highly correlated and exhibited close quantitative agreement with those produced by HPLC. While the PSP receptor binding assay does not provide information on toxin composition obtainable by HPLC, it does represent a robust and reliable means of rapidly assessing PSP-like toxicity in laboratory and field samples. Moreover, this assay should be effective as a screening tool for use by public health officials in responding to suspected cases of PSP intoxication.
44 citations
TL;DR: Although reporter gene assays are not designed to replace existing detection methods used to measure toxin activity in seafood, they do provide a valuable means to screen algal cultures for toxin activity, to conduct assay-guided fractionation and to characterize pharmacologic properties of algal toxins.
Abstract: We have modified the cell-based directed cytotoxicity assay for sodium channel and calcium channel active phycotoxins using a c-fos-luciferase reporter gene construct. In this report we describe the conceptual basis to the development of reporter gene assays for algal-derived toxins and summarize both published and unpublished data using this method. N2A mouse neuroblastoma cells, which express voltage-dependent sodium channels, were stably transfected with the reporter gene c-fos-luc, which contains the firefly luciferase gene under the transcriptional regulation of the human c-fos response element. The characteristics of the N2A reporter gene assay were determined by dose response with brevetoxin and ciguatoxin. Brevetoxin-1 and ciguatoxin-1 induced c-fos-luc with an EC50 of 4.6 and 3.0 ng ml−1, respectively. Saxitoxin caused a concentration-dependent inhibition of brevetoxin-1 induction of c-fos-luc with an EC50 of 3.5 ng ml−1. GH4C1 rat pituitary cells, which lack voltage-dependent sodium channels but express voltage-dependent calcium channels, were also stably transfected with the c-fos-luc. GH4C1 cells expressing c-fos-luciferase were responsive to maitotoxin (1 ng ml−1) and a putative toxin produced by Pfiesteria piscicida. Although reporter gene assays are not designed to replace existing detection methods used to measure toxin activity in seafood, they do provide a valuable means to screen algal cultures for toxin activity, to conduct assay-guided fractionation and to characterize pharmacologic properties of algal toxins. Published in 1999 by John Wiley & Sons, Ltd.
TL;DR: The South Atlantic Bight Recruitment Experiment (SABRE) brought together a interdisciplinary team of scientists to conduct research to enhance our understanding of the relationship between variation in environmental factors and the variable recruitment of ‘estuarine dependent’ fishes within the SAB as discussed by the authors.
Abstract: The South Atlantic Bight Recruitment Experiment (SABRE) brought together a interdisciplinary team of scientists to conduct research to enhance our understanding of the relationship between variation in environmental factors and the variable recruitment of ‘estuarine dependent’ fishes within the SAB. The project sought to develop a new fusion of government and academic scientists, each possessing unique skills, to address the difficult problem of recruitment variability in fishes. This fusion required the development of appropriate and at that time novel management and administrative strategies. SABRE initially focused on recruitment dynamics of Atlantic menhaden, Brevoortia tyrannus, in the South Atlantic Bight, but expanded over time to include several estuarine-dependent species and much of the Middle Atlantic Bight as well. The project was conducted from 1991 to 1997 and resulted in a substantial improvement in our understanding of the life history and ecology of Atlantic menhaden and the potential constraints upon its recruitment. SABRE also contributed to our understanding of the physical oceanography of the western North Atlantic shelf and adjacent coastal inlets and the implications of physical dynamics upon the potential pathways for larval transport.
TL;DR: The use of DDT (an organochlorine insecticide) has been banned in Europe and North America and other industrialized nations, but in other parts of the world, it is intensively used as an insecticide to control vectors of diseases such as malaria, plague, typhus fever, yellow fever, sleeping sickness, and river blindness.
Abstract: The use of DDT (an organochlorine insecticide) has been banned in Europe and North America and other industrialized nations. However, in other parts of the world, it is intensively used as an insecticide to control vectors of diseases such as malaria, plague, typhus fever, yellow fever, sleeping sickness, and river blindness, and to control agricultural pests. It is also used in forestry management to control pests such as the spruce bud-worm and the Dutch Elm disease (Laws 1981). DDT is a very effective insecticide with a relatively low toxicity towards humans (Pine et al. 1980). Its use as an insecticide is still recommended by the Food and Agriculture Organization of the United Nations.
13 Sep 1999
TL;DR: In this article, the authors describe four case studies of in-situ burning, each representing a different scenario: on the open sea, in a river, inside a wetland, and inside a stranded vessel.
Abstract: In-situ burning of spilled oil has some distinct advantages as a response option. Throughout the United States over the last decade, research, field tests, and development of guidelines have advanced the understanding and use of in-situ burning. The lessons learned from past spill incidents about the effectiveness of in-situ burning can facilitate its consideration at future spills. To that end, the author describes four case studies of in-situ burning, each representing a different scenario: on the open sea, in a river, in a wetland, and inside a stranded vessel. Although the circumstances of these burns differ, it is evident that in-situ burning can effectively remove spilled oil from the environment. In-situ burning is not suitable for all spill situations, and there are issues that need to be resolved.
TL;DR: In this paper, the authors presented a real-time positioning of a ship to within 10 cm (about 4 inches) relative to the bottom of the shipping channel using a differential global positioning system.
Abstract: With the availability of high-accuracy, differential global positioning system (GPS) results in real-time, there is a new opportunity to use GPS to accurately measure a marine vessel's dynamic draft (settlement and squat) and 3D attitude (roll, pitch, and heading). The National Geodetic Survey (NGS) and the Coast Survey (CS), offices of the National Ocean Service (NOS), National Oceanic and Atmospheric Administration (NOAA), propose to transfer this technology to the shipping industry. The overall goal of this project is to provide the position of a vessel's keel in real time to within 10 cm (about 4 inches) relative to the bottom of the shipping channel. In support of this phase of the project, there were three meetings hosted by the Port of Oakland, California and NOS to discuss the real-time positioning of vessels project. On December 3 and 4, 1996, CS, NGS, Trimble Navigation Ltd., and the U. S. Coast Guard (USCG) performed GPS tests on a USCG buoy-tender ship. GPS data were used to compute the vessel's dynamic draft and 3D attitude. During the test, five receivers continually collected data; one receiver was located at a base station on the USCG pier on Yerba Buena Island, and four were on the ship: two on the stern and two on the bow. CS installed a TSS-335B vertical reference unit (to measure heave, pitch, and roll) in the engine room of the ship. NOS processed the GPS data and computed the vessel's dynamic draft and 3D attitude. The results indicate that the linear equivalent to the vessel's dynamic draft and 3D attitude were accurate to the 10-cm level using GPS. It was also demonstrated how a ship can be used to measure local water-level changes and actual water-level values everywhere it travels. © 1999 John Wiley & Sons, Inc.
01 Jan 1999
TL;DR: SABRE provided new scientific insights into the fisheries oceanography of the estuarine-dependent fishes of the South Atlantic Bight and gained insights on the coupling of physics to biology in the early life history of a number of marine fishes.
Abstract: In this paper, we highlight the major results from the SABRE programme and applications to research and management. In particular, SABRE provided new scientific insights into the fisheries oceanography of the estuarine-dependent fishes of the South Atlantic Bight. Although we concentrated our efforts on Atlantic menhaden, we also gained insights on the coupling of physics to biology in the early life history of a number of marine fishes. Larval transport from spawning sites to and through barrier island inlets is now better understood. Analysis of menhaden population dynamics suggests survival in the late larval/early juvenile stage is particularly important to population growth. This phase of the life history appears likely to present a bottleneck to recruitment for Atlantic menhaden. We also made a number of technological breakthroughs which are already being applied elsewhere in research and assessments including the Continuous, Underway Egg Sampler (CUFES), enzyme-based approaches to evaluating condition of individual larvae and various physical and biological modelling innovations. Our experiences establishing and managing the SABRE research team also provide insights into one model for promoting multidisciplinary research in fisheries oceanography. Throughout SABRE, we have sought an open exchange of information and insights from a wide variety of researchers and environmental managers. We hope the synthesis provided here continues that dialogue.
13 Sep 1999
TL;DR: The Coastal Marine Demonstration (CMD) project as discussed by the authors was developed jointly by government, academia and industry, encompassing twelve partners, and was funded by the National Ocean Partnership Program.
Abstract: A stated goal of the NOAA is to provide a capability to measure, understand, analyze, and forecast coastal environmental phenomena that impact coastal economies, public safety, and environmental management. A partnership project was established to demonstrate the capability of providing improved coastal marine environmental information to a selected group of marine customers in a major port of the United States, and was funded by the National Ocean Partnership Program. The Coastal Marine Demonstration (CMD) was developed jointly by government, academia and industry, encompassing twelve partners. As a major partner, NOAA has embarked on a plan to improve predictions and develop new products based on coastal forecasting experiments and advancements in modeling capability for the coupled ocean and atmosphere. Coastal modeling and information systems have progressed to the point that such a demonstration is not only feasible but also practical. The project integrates experimental forecast products under development for coastal waters, harbours, and bays, with higher resolution atmospheric forecasts; and new methods for dissemination and display of coastal environmental information. The project is a strong test of the coastal observation networks. The CMD project tests the state of the art in marine forecasting and evaluates the potential benefits of experimental higher resolution predictions. Oceanographic and meteorological forecasts for Norfolk Harbor, Chesapeake Bay, and neighboring Atlantic shelf waters are provided for evaluation to a group of customers including harbour pilots and masters, shipping agents, and ship captains while both ashore and at sea.