scispace - formally typeset
Search or ask a question
Author

Peter E. Miller

Bio: Peter E. Miller is an academic researcher from University of California, Santa Cruz. The author has contributed to research in topics: Domoic acid & Pseudo-nitzschia. The author has an hindex of 20, co-authored 25 publications receiving 2616 citations. Previous affiliations of Peter E. Miller include Monterey Bay Aquarium Research Institute & Southern California Coastal Water Research Project.

Papers
More filters
Journal ArticleDOI
06 Jan 2000-Nature
TL;DR: Findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.
Abstract: Over 400 California sea lions (Zalophus californianus) died and many others displayed signs of neurological dysfunction along the central California coast during May and June 1998. A bloom of Pseudo-nitzschia australis (diatom) was observed in the Monterey Bay region during the same period. This bloom was associated with production of domoic acid (DA), a neurotoxin1 that was also detected in planktivorous fish, including the northern anchovy (Engraulis mordax), and in sea lion body fluids. These and other concurrent observations demonstrate the trophic transfer of DA resulting in marine mammal mortality. In contrast to fish, blue mussels (Mytilus edulus) collected during the DA outbreak contained no DA or only trace amounts. Such findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.

794 citations

Journal ArticleDOI
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

Journal ArticleDOI
TL;DR: A study of 25 cultures tentatively identified as Pseudo‐nitzschia delicatissima (Cleve) Heiden showed both morphological and genetic variation among strains, and resulted in the description of two new species, P. decipiens sp.
Abstract: A study of 25 cultures tentatively identified as Pseudo-nitzschia delicatissima (Cleve) Heiden, and originating from geographically widely distributed locations, showed both morphological and genetic variation among strains. Use of rRNA-targeted DNA probes on 17 different strains showed large variation in the hybridization patterns. Detailed morphological studies placed the isolates into three groups. The sample on which the neotype of P. delicatissima is based was also examined, and used to establish the morphological identity of P. delicatissima. Phylogenetic analyses of 16 strains, based on sequences of internal transcriber spacer 1 (ITS1), 5.8S and ITS2 of the nuclear-encoded rDNA, supported the morphological observations and the hybridization studies, and revealed large genetic variation among strains. A combination of the morphological and molecular findings resulted in the description of two new species, P. decipiens sp. nov. and P. dolorosa sp. nov. P. dolorosa has a mixture of one or two rows of poroids in the striae whereas P. delicatissima always has two rows. In addition, P. dolorosa has wider valves and a lower density of poroids. P. decipiens differs from P. delicatissima by a higher density of striae on the valve face as well as a higher density of poroids on the girdle bands. Among the strains referred to P. delicatissima, an epitype was selected. Large genetic variation was found among the P. delicatissima strains and a subdivision into two major clades represent cryptic species.

190 citations

Journal ArticleDOI
TL;DR: Efforts to develop species‐specific large subunit ribosomal RNA (LSU rRNA)‐targeted fluorescent DNA probes for a variety of Pseudo‐nitzschia H. Peragallo species are continued.
Abstract: Efforts to understand the ecologic and environmental parameters that govern harmful algal blooms (HABs) require rapid and specific identification of causative species. Traditional methods of species identification using light and electron microscopy are useful in this regard but are also time consuming, making routine analysis of a large number of samples difficult. Techniques that speed and ease the detection of HAB species as they occur in natural populations are therefore desirable. In this paper, we continue efforts to develop species-specific large subunit ribosomal RNA (LSU rRNA)-targeted fluorescent DNA probes for a variety of Pseudo-nitzschia H. Peragallo species, a group of marine pennate diatoms that includes representatives linked to production of domoic acid and amnesic shellfish poisoning (ASP). A custom filter tube and filtration manifold that has utility for both whole cell (in situ) hybridization as well as preparing samples for scanning electron microscopy (SEM) is described. Filter-based whole cell hybridization was used to identify a variety of newly isolated Pseudo-nitzschia clones, and probe results were confirmed using SEM. Some isolates of P. pungens (Grunow) Hasle exhibited variable (intraclonal) reactivity toward the P. pungens-specific probe. Three isolates of P. subpacifica (Hasle) Hasle were found to cross-react with probes designed for P. fraudulenta (Cleve) Hasle and P. heimii Manguin. Four isolates did not react with any species-specific probes; this group comprised three distinct morphotypes whose fine-scale morphologic features did not agree with published descriptions of Pseudo-nitzschia species. Evaluation of the filter method using cultured cells added to natural (whole water) samples indicated quantitative recovery of target species. Confirming results of probe assays using SEM was difficult when the target species was less than 10 4 cells·L 21 in the presence of greater than 106 cells·L 21 of other nontarget diatom species. A variety of Pseudo-nitzschia, including P. australis Frenguelli, P. fraudulenta, P. heimii, P. pseudodelicatissima (Hasle) Hasle, P. pungens, P. multiseries (Hasle) Hasle, and Nitzschia americana Hasle, were identified using whole cell hybridization in a variety of field samples containing mixed assemblages of plankton, and these results were confirmed using SEM. The filter tube method of applying probes was used onboard ship for near real-time identification and enumeration of a variety of Pseudonitzschia species.

178 citations

Journal ArticleDOI
TL;DR: In the Southern California Bight (SCB) along the coasts of Los Angeles and Orange Counties during spring and summer of 2003 and 2004 as mentioned in this paper, Pseudo-nitzschia australis dominated the Pseudo Nitzchia assemblage and concentrations of particulate domoic acid (DA) were determined.

177 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: The relationship between harmful algal blooms and eutrophication of coastal waters from human activities has been investigated in this paper, focusing on sources of nutrients, known effects of nutrient loading and reduction, new understanding of pathways of nutrient acquisition among HAB species, and relationships between nutrients and toxic algae.
Abstract: Although algal blooms, including those considered toxic or harmful, can be natural phenomena, the nature of the global problem of harmful algal blooms (HABs) has expanded both in extent and its public perception over the last several decades. Of concern, especially for resource managers, is the potential relationship between HABs and the accelerated eutrophication of coastal waters from human activities. We address current insights into the relationships between HABs and eutrophication, focusing on sources of nutrients, known effects of nutrient loading and reduction, new understanding of pathways of nutrient acquisition among HAB species, and relationships between nutrients and toxic algae. Through specific, regional, and global examples of these various relationships, we offer both an assessment of the state of understanding, and the uncertainties that require future research efforts. The sources of nutrients poten- tially stimulating algal blooms include sewage, atmospheric deposition, groundwater flow, as well as agricultural and aquaculture runoff and discharge. On a global basis, strong correlations have been demonstrated between total phos- phorus inputs and phytoplankton production in freshwaters, and between total nitrogen input and phytoplankton pro- duction in estuarine and marine waters. There are also numerous examples in geographic regions ranging from the largest and second largest U.S. mainland estuaries (Chesapeake Bay and the Albemarle-Pamlico Estuarine System), to the Inland Sea of Japan, the Black Sea, and Chinese coastal waters, where increases in nutrient loading have been linked with the development of large biomass blooms, leading to anoxia and even toxic or harmful impacts on fisheries re- sources, ecosystems, and human health or recreation. Many of these regions have witnessed reductions in phytoplankton biomass (as chlorophyll a) or HAB incidence when nutrient controls were put in place. Shifts in species composition have often been attributed to changes in nutrient supply ratios, primarily N:P or N:Si. Recently this concept has been extended to include organic forms of nutrients, and an elevation in the ratio of dissolved organic carbon to dissolved organic nitrogen (DOC:DON) has been observed during several recent blooms. The physiological strategies by which different groups of species acquire their nutrients have become better understood, and alternate modes of nutrition such as heterotrophy and mixotrophy are now recognized as common among HAB species. Despite our increased un- derstanding of the pathways by which nutrients are delivered to ecosystems and the pathways by which they are assimilated differentially by different groups of species, the relationships between nutrient delivery and the development of blooms and their potential toxicity or harmfulness remain poorly understood. Many factors such as algal species presence/ abundance, degree of flushing or water exchange, weather conditions, and presence and abundance of grazers contribute to the success of a given species at a given point in time. Similar nutrient loads do not have the same impact in different environments or in the same environment at different points in time. Eutrophication is one of several mechanisms by which harmful algae appear to be increasing in extent and duration in many locations. Although important, it is not the only explanation for blooms or toxic outbreaks. Nutrient enrichment has been strongly linked to stimulation of some harmful species, but for others it has not been an apparent contributing factor. The overall effect of nutrient over- enrichment on harmful algal species is clearly species specific.

2,500 citations

Journal ArticleDOI
TL;DR: In this article, a global assessment of the effects of inorganic nitrogen pollution in aquatic ecosystems is presented, with detailed multi-scale data, and three major environmental problems: (1) increasing the concentration of hydrogen ions in freshwater ecosystems without much acid-neutralizing capacity, resulting in acidification of those systems; (2) stimulating or enhancing the development, maintenance and proliferation of primary producers, leading to eutrophication of aquatic ecosystems; (3) reaching toxic levels that impair the ability of aquatic animals to survive, grow and reproduce.

1,753 citations

Journal ArticleDOI
TL;DR: The Effects of Harmful Algal Blooms on Aquatic Organisms: Vol. 10, No. 2, pp. 113-390 as mentioned in this paper was the first publication of this article.
Abstract: (2002). The Effects of Harmful Algal Blooms on Aquatic Organisms. Reviews in Fisheries Science: Vol. 10, No. 2, pp. 113-390.

1,242 citations

Journal ArticleDOI
06 Jan 2000-Nature
TL;DR: Findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.
Abstract: Over 400 California sea lions (Zalophus californianus) died and many others displayed signs of neurological dysfunction along the central California coast during May and June 1998. A bloom of Pseudo-nitzschia australis (diatom) was observed in the Monterey Bay region during the same period. This bloom was associated with production of domoic acid (DA), a neurotoxin1 that was also detected in planktivorous fish, including the northern anchovy (Engraulis mordax), and in sea lion body fluids. These and other concurrent observations demonstrate the trophic transfer of DA resulting in marine mammal mortality. In contrast to fish, blue mussels (Mytilus edulus) collected during the DA outbreak contained no DA or only trace amounts. Such findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.

794 citations