Search results

Title: Phylogenetic relationships of yessotoxin-producing dinoflagellates, based on the large subunit and internal transcribed spacer ribosomal DNA domains
Description: Yessotoxin (YTX) is a globally distributed marine toxin produced by some isolates of the dinoflagellate species Protoceratium reticulatum, Lingulodinium polyedrum, and Gonyaulax spinifera within the order Gonyaulacales. The process of isolating cells and testing each isolate individually for YTX production during toxic blooms are labor intensive, and this impedes our ability to respond quickly to toxic blooms. In this study, we used molecular sequences from the large subunit and internal transcribed spacer genomic regions in the ribosomal operon of known YTX-producing dinoflagellates to determine if genetic differences exist among geographically distinct populations or between toxic and nontoxic isolates within species. In all analyses, all three YTX-producing species fell within the Gonyaulacales order in agreement with morphological taxonomy. Phylogenetic analyses of available rRNA gene sequences indicate that the capacity for YTX production appears to be confined to the order Gonyaulacales. These findings indicate that Gonyaulacoloid dinoflagellate species are the most likely to produce YTX and thus should be prioritized for YTX screening during events. Dinoflagellate species that fall outside of the Gonyaulacales order are unlikely to produce YTX. Although the rRNA operon offers multiple sequence domains to resolve species level diversification within this dinoflagellate order, these domains are not sufficiently variable to provide robust markers for YTX toxicity. © 2009, American Society for Microbiology. All Rights Reserved., Cited By (since 1996):8, CODEN: AEMID, Downloaded from: http://aem.highwire.org/content/75/1/54.full.pdf+html (13 June 2014).
Author: Howard, Smith, Kudela
Date: 2009-01-01T00:00:00Z

Title: Temporal variation in the artisanal elasmobranch fishery of Sonora, Mexico,
Description: Baseline, species-specific information is largely unavailable for artisanal elasmobranch fisheries, but is essential for the monitoring of exploited populations and the development of effective management plans. Seasonal surveys were conducted during 1998-1999 in Sonora, Mexico to determine the extent and activities of artisanal elasmobranch fisheries operating in the eastern Gulf of California. Nineteen fishing sites were documented, the majority of which (84.2%) targeted elasmobranchs during some part of the year. Most small demersal sharks and rays were landed in bottom set gillnet fisheries that also targeted demersal teleosts, whereas large sharks were usually taken in directed surface longline or, to a lesser extent, drift gillnet fisheries. Rays numerically dominated sampled landings in Sonora (63.4%, n = 100,136), and catch rates exceeded those of sharks during spring and summer months. The shovelnose guitarfish, Rhinobatos productus, was the primary fishery target during these seasons. During autumn, small sharks, especially mustelids (Mustelus spp.) were numerically dominant, but rays (e.g., Dasyatis dipterura) were also caught in large numbers. Winter landings in Sonora were principally composed of mustelid sharks, which represented the greatest seasonal catch rates of all elasmobranch taxa during this study. Large sharks were of comparably minor importance, with a limited summer fishery operating in the southern part of the state. Variation in catch composition was evident in association with differential interannual environmental conditions (El Niño and La Niña) and seasonal temperature fluctuations. Size composition of landings varied greatly by species, but relatively small size classes of sharks and rays were abundant and large, often gravid females of several ray species (e.g., R. productus and Narcine entemedor) supported spring and summer fisheries in nearshore waters. Populations of many large shark species (e.g., Carcharhinus leucas, Carcharhinus limbatus, Carcharhinus obscurus and Galeocerdo cuvier) have likely been overfished, prompting a shift in effort towards coastal populations of smaller elasmobranchs. © 2009 Elsevier B.V. All rights reserved., Cited By (since 1996):13, Fish and Fisheries, CODEN: FISRD, ,
Author: Bizzarro, Smith, Márquez-Farías, Tyminski, Hueter
Date: 2009-01-01T00:00:00Z

Title: Evolution of Macrocystis spp. (Phaeophyceae) as determined by ITS1 and ITS2 sequences
Description: Macrocystis (Lessoniaceae) displays an antitropical distribution, occurring in temperate subtidal regions along western North America in the northern hemisphere and throughout the southern hemisphere. We used the noncoding rDNA internal transcribed spacer regions (ITS1 and ITS2) to examine relatedness among (1) Macrocystis and several genera of Laminariales, (2) four species of Macrocystis (M. integrifolia Bory from the northern hemisphere, M. angustifolia Bory and M. laevis Hay from the southern hemisphere, and M. pyrifera [L.] C. Ag. from both hemispheres), and (3) multiple clones of several individuals. Of the taxa included in our phylogenetic analysis, the elk kelp, Pelagophycus porra (Lem.) Setch., was the sister taxon to Macrocystis spp. Macrocystis individuals from the southern hemisphere (representing three species) formed a strongly to moderately supported clade, respectively, when the ITS1 and ITS2 sequences were analyzed separately. No distinction was detected between the two species in the northern hemisphere. Thus, Macrocystis may be a monospecific genus (M. pyrifera). A northern-hemisphere-to-southern-hemisphere pattern of dispersal was inferred, because northern-hemisphere individuals were more diverse and displayed paraphyletic clades, whereas southern-hemisphere individuals were less diverse and formed a monophyletic clade. High intraindividual variation in ITS1 sequences was observed in one individual from Santa Catalina Island (CA), suggesting very recent and rapid mixing of genotypes from areas to the north and Baja California (Mexico) or introgressive hybridization with Pelagophycus., Cited By (since 1996):67, Seaweeds, CODEN: JPYLA
Author: Coyer, Smith, Andersen
Date: 2001-01-01T00:00:00Z

Title: Macrofaunal abundance and composition on the West Antarctic Peninsula continental shelf,
Description: To assess the impact and fate of the summer phytoplankton bloom on Antarctic benthos, we evaluated temporal and spatial patterns in macrofaunal abundance and taxonomic composition along a transect crossing the West Antarctic Peninsula (WAP) continental shelf. As part of the FOODBANCS project, we sampled three sites at 550-625 m depths during five cruises occurring in November 1999, February-March 2000, June 2000, October 2000 and March 2001. We used a combination of megacore and box-core samplers to take 81 samples, and collected over 30,000 macrofaunal individuals, one of the largest sampling efforts on the Antarctic shelf to date. Comparison of the two sampling methodologies (box core and megacore) indicates similar macrofaunal densities, but with significant differences in taxonomic composition, a reflection of the different spatial scales of sampling. Macrofaunal abundances on the WAP shelf were relatively high compared to other Antarctic shelf settings. At two of the three sampling sites, macrofaunal abundance remained constant throughout the year, which is consistent with the presence of a sediment 'food bank'. Differences were observed in taxonomic composition at the site closest to the coast (Station A), driven by higher abundances of sub-surface-deposit feeders. A significant temporal response was observed in the ampharetid polychaetes at Station A, with an abundance peak in the late fall post-bloom period; this may have resulted from juvenile recruitment during the summer bloom. Familial composition of macrofaunal polychaetes on the WAP shelf is more closely related to deep-sea abyssal fauna than to other shelf regions, and we hypothesize that this is a result of both local ecological conditions (low temperatures) and a reflection of historical processes such as extinctions on the Antarctic shelf during previous glacial maxima followed by recolonization from the deep sea. © 2008 Elsevier Ltd. All rights reserved., Cited By (since 1996):4, Invertebrates, Antarctica, CODEN: DSROE, ,
Author: Glover, Smith, Mincks, Sumida, Thurber
Date: 2008-01-01T00:00:00Z

Title: Transport makes the difference,
Description: , CODEN: JPYLA, , ,
Author: Smith
Date: 2000-01-01T00:00:00Z

Title: Ozone depletion: Ultraviolet radiation and phytoplankton biology in Antarctic waters,
Description: The springtime stratospheric ozone (O 3) layer over the Antarctic is thinning by as much as 50 percent, resulting in increased midultraviolet (UVB) radiation reaching the surface of the Southern Ocean. There is concern that phytoplankton communities confined to near-surface waters of the marginal ice zone will be harmed by increased UVB irradiance penetrating the ocean surface, thereby altering the dynamics of Antarctic marine ecosystems. Results from a 6-week cruise (Icecolors) in the marginal ice zone of the Bellingshausen Sea in austral spring of 1990 indicated that as the O 3 layer thinned: (i) sea surface- and depth-dependent ratios of UVB irradiance (280 to 320 nanometers) to total irradiance (280 to 700 nanometers) increased and (ii) UVB inhibition of photosynthesis increased. These and other Icecolors findings suggest that O 3-dependent shifts of in-water spectral irradiances alter the balance of spectrally dependent phytoplankton processes, including photoinhibition, photoreactivation, photoprotection, and photosynthesis. A minimum 6 to 12 percent reduction in primary production associated with O 3 depletion was estimated for the duration of the cruise., Cited By (since 1996):544, CODEN: SCIEA, ,
Author: Smith, Prézelin, Baker, Bidigare, Boucher, Coley, Karentz, Macintyre, Matlick, Menzies, Ondrusek, Wan, Waters
Date: 1992-01-01T00:00:00Z

Title: Surveillance for zoonotic and selected pathogens in harbor seals phoca vitulina from central California
Description: The infection status of harbor seals Phoca vitulina in central California, USA, was evaluated through broad surveillance for pathogens in stranded and wild-caught animals from 2001 to 2008, with most samples collected in 2007 and 2008. Stranded animals from Mendocino County to San Luis Obispo County were sampled at a rehabilitation facility: The Marine Mammal Center (TMMC, n = 175); wild-caught animals were sampled at 2 locations: San Francisco Bay (SF, n = 78) and Tomales Bay (TB, n = 97), that differed in degree of urbanization. Low prevalences of Salmonella, Campylobacter, Giardia, and Cryptosporidium were detected, in the feces of stranded and wild-caught seals. Clostridium perfringens and Escherichia coli were more prevalent in the feces of stranded (58% [78 out of 135] and 76% [102 out of 135]) than wild-caught (42% [45 out of 106] and 66% [68 out of 106]) seals, whereas Vibrio spp. were 16 times more likely to be cultured from the feces of seals from SF than TB or TMMC (p < 0.005). Brucella DNA was detected in 3.4% of dead stranded harbor seeds (2 out of 58). Type A influenza was isolated from feces of 1 out of 96 wild-caught seals. Exposure to Toxoplasma gondii, Sarcocystis neurona, and type A influenza was only detected in the wild-caught harbor seals (post-weaning age classes), whereas antibody titers to Leptospira spp. were detected in stranded and wild-caught seals. No stranded (n = 109) or wild-caught (n = 217) harbor seals had antibodies to phocine distemper virus, although a single low titer to canine distemper virus was detected. These results highlight the role of harbor seals as sentinel species for zoonotic and terrestrial pathogens in the marine environment., Harbor Seals
Author: Greig, Gulland, Smith, Conrad, Field, Fleetwood, Harvey, Ip, Jang, Packham, Wheeler, Hall

Title: Using the molecular toolbox to compare harmful algal blooms in upwelling systems,
Description: Harmful algal blooms (HABs) are now generally recognized as occurring over a wide range of habitats from oligotrophic to hypernutrified, and appear to be expanding globally. Unlike many other ecosystems impacted by HABs, upwelling systems worldwide share a common set of physical parameters and are likely to respond similarly, regardless of locale. The Core Research Project on HABs in Upwelling Systems, a component of the scientific programme on the Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB), promotes a comparative approach to identify the similarities and differences in the manifestation of HAB events in these systems. As applied to the goals of this programme, molecular techniques are a powerful suite of tools for HAB species identification, for determining genetic similarity within morphologically indistinguishable species, and ultimately, for assessing spatial and temporal patterns in ecophysiological responses in these upwelling systems. Knowledge of HAB organisms will be enhanced by comparing and contrasting the responses of these organisms in similar upwelling regions. Here, we provide an update on the availability of molecular and genetic tools for comparative HAB programmes in upwelling systems, focusing on four broad applications: cell enumeration and identification, molecular phylogenetics, functional/comparative genomics, and applications of high throughput sequencing methods. We highlight the rapid evolution, the promise, and the potential pitfalls, of the molecular toolbox, focusing on specific examples of how scientists and resource managers currently apply these methods. Specific examples are developed using relevant case studies from the California, Benguela and Iberian systems. We summarise by providing a synthesis of future research directions and goals that would be particularly relevant to advancing the comparative method for HAB genetics with an emphasis on upwelling systems. © 2010 Elsevier Ltd. All rights reserved., Cited By (since 1996):6, CODEN: POCNA, , , Oceanography
Author: Kudela, Howard, Jenkins, Miller, Smith
Date: 2010-01-01T00:00:00Z

Title: Characterization of a cDNA encoding glutamine synthetase from the marine diatom Skeletonema costatum (Bacillariophyceae),
Description: A cDNA-encoding glutamime synthetase (GS) was isolated from the marine diatom Skeletonema costatum (Greville) Cleve by PCR amplification. Nucleic acid and deduced amino acid sequences of the diatom GS were greater than 50% identical to GS from green algae and vascular plants, and phylogenetic analysis established the diatom GS as a member of the GSII gene family. The presence of an N-terminus signal sequence, identified on the basis of sequence similarity with other chloroplast-localized proteins from diatoms, suggests that the encoded GS isoenzyme is localized to the chloroplast. The GS mRNA was present in log-phase cells grown with either nitrate or ammonium as the sole added nitrogen source. Results from Southern blot analysis of genomic DNA suggested that the cDNA isolated in this study was either a member of a small, highly conserved gene family or that there was allelic variation within the region examined. Phylogenetic analyses further indicated that genes encoding GS from the diatom and two species of green algae diverged prior to the gene duplication, to the isoenzymes in vascular plants, supporting the hypothesis that GS isoenzymes in diatoms, green algae, and vascular plants arose through independent evolutionary events., Cited By (since 1996):16, Seaweeds, CODEN: JPYLA, ,
Author: Robertson, Smith, Alberte
Date: 1999-01-01T00:00:00Z

Title: Demography and elasticity of the diamond stingray, Dasyatis dipterura,
Description: Despite their abundance in near-shore tropical and subtropical marine environments, which support much of the world's elasmobranch fisheries, population dynamics and impacts of fisheries on stingrays are poorly documented. Age-structured demographic models were developed using empirical estimates of fecundity, longevity and maturity to project population growth parameters and potential responses to fishing mortality of Dasyatis dipterura from the Bahía Magdalena lagoon complex, México. Monte Carlo simulation was incorporated to include uncertainty in life history parameters into model projections. Six models were developed using deterministic and probabilistic approaches under unexploited and exploited (fishing mortality ≤ 0.05 year-1) conditions. Mean annual population growth rates (γ) of 1.05-1.06 (5-6% increase), net reproductive rates of 2.3-2.4 and generation times of 14.9-16.5 years were projected from simulations. The introduction of a low fishing mortality into probabilistic models produced γ of 1.01 year-1. Elasticity analysis indicated that population growth rates for D. dipterura are more strongly influenced by the survival of juvenile and adult stages than by survival of neonates or changes in fecundity. Demographic analyses indicated that D. dipterura has a low intrinsic growth potential and limited resilience to fishing pressure. Localised depletion or population collapses are therefore likely to occur through unrestricted, unmonitored fishing effort. © CSIRO 2008., Cited By (since 1996):13, ,
Author: Smith, Cailliet, Cort́s
Date: 2008-01-01T00:00:00Z

Title: Calibration and evaluation of five indicators of benthic community condition in two California bay and estuary habitats,
Description: Many types of indices have been developed to assess benthic invertebrate community condition, but there have been few studies evaluating the relative performance of different index approaches. Here we calibrate and compare the performance of five indices: the Benthic Response Index (BRI), Benthic Quality Index (BQI), Relative Benthic Index (RBI), River Invertebrate Prediction and Classification System (RIVPACS), and the Index of Biotic Integrity (IBI). We also examine whether index performance improves when the different indices, which rely on measurement of different properties, are used in combination. The five indices were calibrated for two geographies using 238 samples from southern California marine bays and 125 samples from polyhaline San Francisco Bay. Index performance was evaluated by comparing index assessments of 35 sites to the best professional judgment of nine benthic experts. None of the individual indices performed as well as the average expert in ranking sample condition or evaluating whether benthic assemblages exhibited evidence of disturbance. However, several index combinations outperformed the average expert. When results from both habitats were combined, two four-index combinations and a three-index combination performed best. However, performance differences among several combinations were small enough that factors such as logistics can also become a consideration in index selection. © 2008 Elsevier Ltd. All rights reserved., Cited By (since 1996):15, Invertebrates, CODEN: MPNBA, ,
Author: Ranasinghe, Weisberg, Smith, Montagne, Thompson, Oakden, Huff, Cadien, Velarde, Ritter
Date: 2009-01-01T00:00:00Z

Title: Reproductive biology of two commercially exploited skates, Raja binoculata and R. rhina, in the western Gulf of Alaska,
Description: This study provides the first detailed information on the reproductive biology of two large and abundant eastern North Pacific Ocean skate species: big skate (Raja binoculata) and longnose skate (Raja rhina). Skates were collected in the western Gulf of Alaska during 2005 and 2006 after a targeted fishery for these two species developed around Kodiak Island, Alaska; both species are also taken as by-catch to other fisheries. A total of 307 females (20.1-183.3 cm TL) and 138 males (19.5-143.7 cm TL) R. binoculata, and 354 females (18.1-145.0 cm TL) and 318 males (21.1-135.8 cm TL) R. rhina were collected. Female R. binoculata were found to attain first (e.g., smallest individual) maturity at 125.8 cm TL and 50% at 148.6 cm TL. Males were found to attain first and 50% maturity at 124.0 and 119.2 cm TL, respectively. No gravid female R. binoculata, with egg cases in utero, were encountered during the study. Female R. rhina were found to attain first and 50% maturity at 102.2 and 113.1 cm TL, respectively. Gravid female R. rhina, with egg cases in utero, were recorded throughout the sampling period. Males attained first maturity at 101.0 cm TL and 50% maturity at 102.9 cm TL. Histological analysis did not reveal significant changes in spermatocyst production for either species during the sampling period. Both species appear to be reproductively active year-round as no seasonal cycle was evident. This study provides new and essential information on the reproductive biology of these two commercially targeted skate species. © 2008 Elsevier B.V. All rights reserved., Cited By (since 1996):8, CODEN: FISRD, ,
Author: Ebert, Smith, Cailliet
Date: 2008-01-01T00:00:00Z

Title: The seasonal importance of small coastal sharks and rays in the artisanal elasmobranch fishery of Sinaloa, Mexico,
Description: Seasonal surveys were conducted during 1998-1999 in Sinaloa, Mexico to determine the extent and activities of the artisanal elasmobranch fishery operating in the southeastern Gulf of California. Twenty-eight fishing sites were documented, the majority of which (78.6%) targeted elasmobranchs during some part of the year. Sharks numerically dominated sampled landings (65.0%, n = 2390), and catch rates exceeded those of rays during autumn-spring. The scalloped hammerhead, Sphyrna lewini, was the primary fishery target during these seasons, with most landings composed of early life stages. During summer, rays, especially Rhinoptera steindachneri, were numerically dominant (87.7%). Large sharks were of comparably minor importance in the artisanal fishery during all seasons. Catch composition was similar between spring and winter (SIMobs = 0.393, SIMexp = 0.415; P = 0.25), largely because the fishery mainly targeted "cazón" (sharks < 1.5 m total length) during this period (e.g., S. lewini, Rhizoprionodon longurio). Small size classes of large sharks and a wide size range of coastal sharks and rays were primarily observed. In addition, size composition of S. lewini and to a lesser extent, R. longurio decreased significantly between historic and contemporary landings. Local populations of these species should therefore be closely monitored., Cited By (since 1996):2, Fish and Fisheries, Source: Scopus, ,
Author: Bizzarro, Smith, Castillo-Géniz, Ocampo-Torres, Márquez-Farías, Hueter
Date: 2009-01-01T00:00:00Z

Title: Evaluation and use of sediment toxicity reference sites for statistical comparisons in regional assessments,
Description: Sediment reference sites were used to establish toxicity standards against which to compare results from sites investigated in San Francisco Bay (California, USA) monitoring programs. The reference sites were selected on the basis of low concentrations of anthropogenic chemicals, distance from active contaminant sources, location in representative hydrographic areas of the Bay, and physical features characteristic of depositional areas (e.g., fine grain size and medium total organic carbon [TOC]). Five field-replicated sites in San Francisco Bay were evaluated over three seasons. Samples from each site were tested with nine toxicity test protocols and were analyzed for sediment grain size and concentrations of trace metals, trace organics, ammonia, hydrogen sulfide, and TOC. The candidate sites were found to have relatively low concentrations of measured chemicals and generally exhibited low toxicity. Toxicity data from the reference sites were then used to calculate numerical tolerance limits to be used as threshold values to determine which test sites had significantly higher toxicity than reference sites. Tolerance limits are presented for four standard test protocols, including solid-phase sediment tests with the amphipods Ampelisca abdita and Eohaustorius estuarius and sea urchin Strongylocentrotus purpuratus embryo/larval development tests in pore water and at the sediment-water interface (SWI). Tolerance limits delineating the lowest 10th percentile (0.10 quantile) of the reference site data distribution were 71% of the control response for Ampelisca, 70% for Eohaustorius, 94% for sea urchin embryos in pore water, and 87% for sea urchins embryos exposed at the SWI. The tolerance limits are discussed in terms of the critical values governing their calculation and the management implications arising from their use in determining elevated toxicity relative to reference conditions., Cited By (since 1996):19, Rocks and Cores, CODEN: ETOCD, ,
Author: Hunt, Anderson, Phillips, Newman, Tjeerdema, Fairey, Puckett, Stephenson, Smith, Wilson, Taberski
Date: 2001-01-01T00:00:00Z

Title: Evaluating ecological states of rocky intertidal communities: A Best Professional Judgment exercise
Description: A Best Professional Judgment (BPJ) exercise was performed to determine the level of agreement among experts in evaluating the ecological states of western North American rocky intertidal communities. Species-abundance and environmental data from 12 central and 11 southern California sites were provided to 14 experts who independently ranked communities from best to worst and assigned each to one of five categories based on the degree of deviation from an expected natural biological state. Experts achieved Spearman correlations of 0.49 (central California) and 0.30 (southern California) in their rankings and averaged 75.4% and 70.0% Euclidean Similarity (ES) in their community evaluations. These ES values compare favorably with agreement levels found for similar exercises with soft bottom macroinvertebrate assemblages. The experts emphasized macrophytes with functional characteristics related to morphology and sessile macroinvertebrates in their assessments. Several challenges were noted in interpreting rocky intertidal data sets, the most prominent of which are high spatial and temporal variation and site-to-site differences in natural disturbance regimes, features that lead to multiple, expected community states. Experts required detailed, physical habitat descriptions to develop community composition expectations that differed for different shore types, and expressed concern about evaluating rocky intertidal communities based on only a single sampling event. Distinguishing natural from anthropogenic disturbance without information on the sources and magnitudes of anthropogenic perturbation was also found to be challenging because the biological responses to these stressors are often similar. This study underscores the need for long-term data sets that describe the dynamics of populations and communities and rigorous testing of expert judgments to firmly establish broadly applicable and consistent links between community states and anthropogenic stressors on rocky shores. © 2015 Elsevier Ltd., Export Date: 11 September 2015
Author: Murray, Weisberg, Raimondi, Ambrose, Bell, Blanchette, Burnaford, Dethier, Engle, Foster, Miner, Nielsen, Pearse, Richards, Smith
Date: 2016-01-01T00:00:00Z

Title: Validated age and growth of the leopard shark, Triakis semifasciata, with comments on reproduction,
Description: The age, growth, and sexual maturation of the leopard shark, Triakis semifasciata, from central California were studied. Growth band counts in vertebral centra of 162 leopard sharks produced von Bertalanffy growth curves with L ∞, K. and t o parameters of 1536 mm. 0.082, and -2.31, respectively, for both sexes combined. The L 8 value for females (1602 mm TL) was slightly but insignificantly higher than for males (1499 mm TL), but the K and t o values were almost identical. Seasonal changes in size modes of young-of-the-year leopard sharks, centrum edge characteristics, and growth and tetracycline mark-recapture from the field were used to validate annual deposition of vertebral centrum band pairs. Sexual maturity was evaluated by the gonads and presence of sperm and eggs; males mature at 7 yr and at about 63% of asymptotic length, and females mature at 10 yr, and at about 72% of asymptotic length. This slow growth, late maturity, and relatively low fecundity may increase their susceptibility to over-exploitation. © 1992 Kluwer Academic Publishers., Cited By (since 1996):53, Fish and Fisheries, CODEN: EBFID, ,
Author: Kusher, Smith, Cailliet
Date: 1992-01-01T00:00:00Z

Title: Condensation of the isoprenoid and amino precursors in the biosynthesis of domoic acid
Description: Understanding how environmental signals regulate production of domoic acid in blooms of Pseudo-nitzschia spp. at a molecular level requires description of the biochemical pathway to this kainoid neurotoxin. Precursor feeding studies have suggested domoic acid arises from the condensation of the C 10 isoprenoid geranyl diphosphate with glutamate, but the specific reactions leading to domoic acid from these precursors remain undescribed. Here, we develop a method to derivatize domoic acid with propyl chloroformate that enables gas chromatography-mass spectrometry (GC-MS) analysis to measure incorporation of stable isotopes into domoic acid generated in cultures incubated with isotopically-labeled substrates. We apply this method to demonstrate that both 2H from [1- 2H 2]geraniol are incorporated into domoic acid, suggesting that the condensation of geranyl diphosphate with an amino group occurs by nucleophilic substitution of the diphosphate rather than by oxidation of geraniol to the aldehyde before reaction with an amino group to form an imine. Ultimately, these and similar studies will facilitate the identification of DA biosynthetic enzymes and genes which will enable the study of how environmental factors regulate DA biosynthesis at the molecular level. © 2011 Elsevier Ltd., Seaweeds, CODEN: TOXIA
Author: Savage, Smith, Clark, Saucedo
Date: 2012-01-01T00:00:00Z

Title: Artisanal fisheries and reproductive biology of the golden cownose ray, Rhinoptera steindachneri Evermann and Jenkins, 1891, in the northern Mexican Pacific,
Description: The golden cownose ray, Rhinoptera steindachneri, was one of the most abundant species landed in artisanal elasmobranch fisheries in the northern Gulf of California (Baja California and Sonora) and Bahía Almejas, Mexico during 1998-1999. In the northern Gulf of California, R. steindachneri was most frequently observed during summer months (11.4% of elasmobranch landings, catch per unit effort (CPUE) = 6.8 individuals/vessel trip) and was rare during winter (0.1%, CPUE = 0.1). In Bahía Almejas, its relative abundance was greater during August (5.2%) than June (0.3%), a trend also evident in CPUE (August = 1.2, June = 0.1). The mean size of R. steindachneri landed in the Gulf of California was 64.3 ± 12.8 (S.D.) cm disc width (DW). Median size at maturity for Gulf of California specimens was similar for females (70.2 cm DW) and males (69.9 cm DW). Fecundity was found to be one offspring per female, with parturition estimated to occur from late June-August. Size at birth was estimated at 38-45 cm DW after a gestation period of approximately 11-12 months. Greater maximum sizes (to 104 cm DW) and embryo sizes (to 43 cm DW) were observed in Bahía Almejas. The large size at maturity, low fecundity, and long gestation period determined for R. steindachneri indicate that this species could be particularly susceptible to overexploitation. © 2006 Elsevier B.V. All rights reserved., Cited By (since 1996):20, Fish and Fisheries, CODEN: FISRD, ,
Author: Bizzarro, Smith, Márquez-Farías, Hueter
Date: 2007-01-01T00:00:00Z

Title: Developing standards for dissolved iron in seawater
Description: Cited By (since 1996):114
Author: Johnson, Boyle, Bruland, Coale, Measures, Moffett, Aguilar-Islas, Barbeau, Bergquist, Bowie, Buck, Cai, Chase, Cullen, Doi, Elrod, Fitzwater, Gordon, King, Laan, Laglera-Baquer, Landing, Lohan, Mendez, Milne, Obata, Ossiander, Plant, Sarthou, Sedwick, Smith, Sohst, Tanner, Van den Berg, Wu
Date: 2007-01-01T00:00:00Z

Title: Maturity and growth characteristics of a commercially exploited stingray, Dasyatis dipterura,
Description: Maturity and growth characteristics were estimated for Dasyatis dipterura from western Mexico, where it is a common component of artisanal elasmobranch fisheries. Median disc width at maturity was estimated as 57.3 cm for females (n = 126) and 46.5 cm for males (n = 55) respectively. Age estimates were obtained from 304 fishery-derived specimens (169 female, 135 male). An annual pattern of band-pair deposition was validated through modified centrum edge and marginal increment analyses. Gompertz, polynomial and von Bertalanffy growth models were fit to disc width and weight-at-age data. Resulting models were evaluated based on biological rationale, standard error of model estimates, and Akaike's information criteria. Growth characteristics differed significantly between females and males. Maximum age estimates were 28 years for females and 19 years for males. Three-parameter von Bertalanffy growth models of disc width-at-age data generated the most appropriate fits and produced relatively low estimates of instantaneous growth rates for females (DW∞ = 92.4 cm, k = 0.05, t0 = -7.61, DW0 = 31.4 cm) and males (DW ∞ = 62.2 cm, k = 0.10, t0 = -6.80, DW0 = 31.3 cm). These values are the lowest reported for myliobatiform stingrays and indicate slow growth rates in comparison with elasmobranchs in general. © CSIRO 2007., Cited By (since 1996):25, CODEN: AJMFA, ,
Author: Smith, Cailliet, Melendez
Date: 2007-01-01T00:00:00Z

Title: Glacial meltwater dynamics in coastal waters west of the Antarctic peninsula,
Description: The annual advance and retreat of sea ice has been considered a major physical determinant of spatial and temporal changes in the structure of the Antarctic coastal marine ecosystem. However, the role of glacial meltwater on the hydrography of the Antarctic Peninsula ecosystem has been largely ignored, and the resulting biological effects have only been considered within a few kilometers from shore. Through several lines of evidence collected in conjunction with the Palmer Station Long-Term Ecological Research Project, we show that the freshening and warming of the coastal surface water over the summer months is influenced not solely by sea ice melt, as suggested by the literature, but largely by the influx of glacial meltwater. Moreover, the seasonal variability in the amount and extent of the glacial meltwater plume plays a critical role in the functioning of the biota by influencing the physical dynamics of the water (e.g., water column stratification, nearshore turbidity). From nearly a decade of observations (1991-1999), the presence of surface meltwater is correlated not only to phytoplankton blooms nearshore, but spatially over 100 km off-shore. The amount of meltwater will also have important secondary effects on the ecosystem by influencing the timing of sea ice formation. Because air temperatures are statistically increasing along the Antarctic Peninsula region, the presence of glacial meltwater is likely to become more prevalent in these surface waters and continue to play an ever-increasing role in driving this fragile ecosystem., Cited By (since 1996):69, CODEN: PNASA, ,
Author: Dierssen, Smith, Vernet
Date: 2002-01-01T00:00:00Z

Title: Trace metals in mussels transplanted to San Francisco Bay,
Description: Mussels (Mytilus californianus) transplanted to San Francisco Bay exhibited elevated trace metal concentrations compared with those in other mussel watch studies on the west coast of the United States. The highest concentrations of Ag, Cu, Hg, Mn, Pb and Zn were at the South Bay stations, and often in the Redwood Creek area. Ag and Hg concentrations were linearly correlated with station distance from the North Bay (San Pablo Bay), indicating that the South Bay is a major reservoir of these pollutants within San Francisco Bay. © 1986., Cited By (since 1996):7, CODEN: ETOCD, ,
Author: Smith, Stephenson, Flegal
Date: 1986-01-01T00:00:00Z

Title: Cytometric quantification of nitrate reductase by immunolabeling in the marine diatom Skeletonema costatum,
Description: Background: The uptake of nitrate by phytoplankton is a central issue in biological oceanography due to its importance to primary production and vertical flux of biogenic carbon. Nitrate reductase catalyzes the first step of nitrate assimilation, the reduction of NO'3 to NO 2. A cytometric protocol to detect and quantify relative changes in nitrate reductase (NR) protein content of the marine centric diatom Skeletonema costatum is presented. Methods: Immunolabeling of NR protein was achieved with polyclonal antibodies raised against S. costatum NR. Antisera specific to a NR protein subunit and to a NR polypeptide sequence were compared and cytometric results of NR protein abundance were related to Western analyses. Changes in cellular NR abundance and activity were followed during an upwelling simulation experiment in which S. costatum was exposed to a shift from ammonia to nitrate as major nitrogen source. Results: NR protein could be detected in NO 3-grown cells and at extremely low levels hardly discernible by Western Blot densiometry in NH 4-grown cells. The protocol allowed observation of early stages of NR induction during an upwelling simulation. NR abundance increased after the nutrient shift to reach a new physiological 'steady- state' 96 hrs later. NR activity exhibited diel variation with maxima at mid- day. NR abundance as estimated by both flow cytometry and Western analysis exhibited a hyperbolic relationship to NR activity. This pattern suggests post-translational activation of NR protein. Conclusions: The presented protocol allows the differentiation of NH 4- versus NO 3-grown algae as well as the monitoring of early stages in the induction of nitrate assimilatory capacities. (C) 2000 Wiley-Liss, Inc., Cited By (since 1996):8 Seaweeds, CODEN: CYTOD, ,
Author: Jochem, Smith, Gao, Zimmerman, Cabello-Pasini, Kohrs, Alberte
Date: 2000-01-01T00:00:00Z

Title: Determination of tributyltin in tissues and sediments by graphite furnace atomic absorption spectrometry,
Description: A method for the determination of tributyltin (TBT) in tissue and sediments has been developed for environmental samples. The technique involves extraction with methylene chloride and isolation of TBT from mono- and dibutyltin with a sodium hydroxide wash. The TBT is then back extracted and converted to elemental Sn with nitric acid. Analysis is by Zeeman graphite furnace atomic absorption spectrophotometry. Recoveries of spiked samples were between 99 % and 111% for mussel and fish tissues and 72% and 99% for various sediments. The limit of quantification was 0.0025 μg/g for tissue (on a wet weight basis). This technique was developed in response to our need to process large numbers of environmental samples with a minimum time investment., Cited By (since 1996):9, ,
Author: Stephenson, Smith
Date: 1988-01-01T00:00:00Z

Title: Domoic acid contamination within eight representative species from the benthic food web of Monterey Bay, California, USA
Description: Benthic food webs often derive a significant fraction of their nutrient inputs from phytoplankton in the overlying waters. If the phytoplankton include harmful algal species like Pseudonitzschia australis, a diatom capable of producing the neurotoxin domoic acid (DA), the benthic food web can become a depository for phycotoxins. We tested the general hypothesis that DA contaminates benthic organisms during local blooms of P. australis, a widespread toxin producer along the US west coast. To test for trophic transfer and uptake of DA into the benthic food web, we sampled 8 benthic species comprising 4 feeding groups: filter feeders (Emerita analoga and Urechis caupo); a predator (Citharichthys sordidus); scavengers (Nassarius fossatus and Pagurus samuelis) and deposit feeders (Neotrypaea californiensis, Dendraster excentricus and Olivella biplicata). Sampling occurred before, during and after blooms of P. australis in Monterey Bay, CA, USA during 2000 and 2001. DA was detected in all 8 species, with contamination persisting over variable time scales. Maximum DA levels in N. fossatus (674 ppm), E. analoga (278 ppm), C. sordidus (515 ppm), TV. californiensis (145 ppm), P. samuelis (56 ppm), D. excentricus (15 ppm) and O. biplicata (3 ppm) coincided with P. australis blooms, while DA levels in U. caupo remained above 200 ppm (max. = 751 ppm) throughout the study period. DA in 6 species exceeded levels thought to be safe for higher level consumers (i.e. ≥20 ppm) and thus is likely to have deleterious effects on marine birds, sea lions and the endangered California sea otter, known to prey upon these benthic species. © Inter-Research 2008., Cited By (since 1996):17, Ecology, CODEN: MESED
Author: Kvitek, Goldberg, Smith, Doucette, Silver
Date: 2008-01-01T00:00:00Z

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