Search results

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: FISH-Flow: A quantitative molecular approach for describing mixed clade communities of Symbiodinium
Description: Our understanding of reef corals and their fate in a changing climate is limited by our ability to monitor the diversity and abundance of the dinoflagellate endosymbionts that sustain them. This study combined two well-known methods in tandem: fluorescent in situ hybridization (FISH) for genotype-specific labeling of Symbiodinium and flow cytometry to quantify the abundance of each symbiont clade in a sample. This technique (FISH-Flow) was developed with cultured Symbiodinium representing four distinct clades (based on large subunit rDNA) and was used to distinguish and quantify these types with high efficiency and few false positives. This technique was also applied to freshly isolated symbionts of Orbicella faveolata and Orbicella annularis. Isolates from acutely bleached coral tissues had significantly lower labeling efficiency; however, isolates from healthy tissue had efficiencies comparable to cultured Symbiodinium trials. RNA degradation in bleaching samples may have interfered with labeling of cells. Nevertheless, we were able to determine that, with and without thermal stress, experimental columns of the coral O. annularis hosted a majority of clade B and B/C symbionts on the top and side of the coral column, respectively. We demonstrated that, for cultured Symbiodinium and Symbiodinium freshly isolated from healthy host tissues, the relative ratio of clades could be accurately determined for clades present at as low as 7 % relative abundance. While this method does not improve upon PCR-based techniques in identifying clades at background levels, FISH-Flow provides a high precision, flexible system for targeting, quantifying and isolating Symbiodinium genotypes of interest. © 2013 Springer-Verlag Berlin Heidelberg.
Author: McIlroy, Smith, Geller
Date: 2014-01-01T00:00:00Z

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: 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: SeaWiFS satellite ocean color data from the Southern Ocean,
Description: SeaWiFS estimates of surface chlorophyll. concentrations are reported for the region of the U.S. JGOFS study in the Southern Ocean (∼ 170 °W, 60 °S). Elevated chlorophyll was observed at the Southern Ocean fronts, near the edge of the seasonal ice sheet, and above the Pacific-Antarctic Ridge. The elevated chlorophyll levels associated with the Pacific-Antarctic Ridge are surprising since even the crest of the ridge is at depths > 2000 m. This elevated phytoplankton biomass is likely the result of mesoscale physical-biological interactions where the Antarctic Circumpolar Current (ACC) encounters the ridge. Four cruises surveyed this region between October 1997 and March 1998, as part of the U.S. JGOFS. Satellite-derived chlorophyll concentrations were compared with in situ extracted chlorophyll measurements from these cruises. There was good agreement (r 2 of 0.72, from a linear regression of shipboard vs. satellite chlorophyll), although SeaWiFS underestimated chlorophyll concentrations relative to the ship data. Copyright 1999 by the American Geophysical Union., Cited By (since 1996):83, CODEN: GPRLA, ,
Author: Moore, Abbott, Richman, Smith, Cowles, Coale, Gardner, Barber
Date: 1999-01-01T00:00:00Z

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: 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: 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: Variable responses of temperate calcified and fleshy macroalgae to elevated pCO2 and warming
Description: Anthropogenic carbon dioxide (CO2) emissions simultaneously increase ocean temperatures and reduce ocean surface pH, a process termed ocean acidification (OA). OA is expected to negatively affect the growth and physiology of many calcified organisms, but the response of non-calcified (fleshy) organisms is less well understood. Rising temperatures and pCO2 can enhance photosynthetic rates (within tolerance limits). Therefore, warming may interact with OA to alter biological responses of macroalgae in complicated ways. Beyond thresholds of physiological tolerance, however, rising temperatures could further exacerbate negative responses to OA. Many studies have investigated the effects of OA or warming independently of each other, but few studies have quantified the interactive effects of OA and warming on marine organisms. We conducted four short-term independent factorial CO2 enrichment and warming experiments on six common species of calcified and fleshy macroalgae from southern California to investigate the independent and interactive effects of CO2 and warming on growth, carbonic anhydrase (CA) enzyme activity, pigment concentrations, and photosynthetic efficiency. There was no effect of elevated pCO2 on CA activity, pigment concentration, and photosynthetic efficiency in the macroalgal species studies.However,we found that calcareous algae suffered reduced growth rates under high pCO2 conditions alone, although the magnitude of the effect varied by species. Fleshy algae had mixed responses of growth rates to high pCO2, indicating that the effects of pCO2 enrichment are inconsistent across species. The combined effects of elevated pCO2 and warming had a significantly negative impact on growth for both fleshy and calcareous algae; calcareous algae experienced five times more weight loss than specimens in ambient control conditions and fleshy growth was reduced by 76%. Our results demonstrate the need to study the interactive effects of multiple stressors associated with global change on marine communities., http://icesjms.oxfordjournals.org/content/early/2015/09/25/icesjms.fsv168.abstract, Advanced view
Author: Kram, Price, Donham, Johnson, Kelly, Hamilton, Smith
Date: 2015-09-25T00:00:00Z

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: 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: Species-specific consequences of ocean acidification for the calcareous tropical green algae Halimeda
Description: Ocean acidification (OA), resulting from increasing dissolved carbon dioxide (CO2) in surface waters, is likely to affect many marine organisms, particularly those that calcify. Recent OA studies have demonstrated negative and/or differential effects of reduced pH on growth, development, calcification and physiology, but most of these have focused on taxa other than calcareous benthic macroalgae. Here we investigate the potential effects of OA on one of the most common coral reef macroalgal genera, Halimeda. Species of Halimeda produce a large proportion of the sand in the tropics and are a major contributor to framework development on reefs because of their rapid calcium carbonate production and high turnover rates. On Palmyra Atoll in the central Pacific, we conducted a manipulative bubbling experiment to investigate the potential effects of OA on growth, calcification and photophysiology of 2 species of Halimeda. Our results suggest that Halimeda is highly susceptible to reduced pH and aragonite saturation state but the magnitude of these effects is species specific. H. opuntia suffered net dissolution and 15% reduction in photosynthetic capacity, while H. taenicola did not calcify but did not alter photophysiology in experimental treatments. The disparate responses of these species to elevated CO2 partial pressure (pCO2) may be due to anatomical and physiological differences and could represent a shift in their relative dominance in the face of OA. The ability for a species to exert biological control over calcification and the species specific role of the carbonate skeleton may have important implications for the potential effects of OA on ecological function in the future. © 2011 Inter-Research., Cited By (since 1996):12, Seaweeds, CODEN: MESED
Author: Price, Hamilton, Tootell, Smith
Date: 2011-01-01T00:00:00Z

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: 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

Title: Evaluating the farming/language dispersal hypothesis with genetic variation exhibited by populations in the Southwest and Mesoamerica,
Description: The Farming/Language Dispersal Hypothesis posits that prehistoric population expansions, precipitated by the innovation or early adoption of agriculture, played an important role in the uneven distribution of language families recorded across the world. In this case, the most widely spread language families today came to be distributed at the expense of those that havemore restricted distributions. In the Americas, Uto-Aztecan is one such language family that may have been spread across Mesoamerica and the American Southwest by ancient farmers. We evaluated this hypothesis with a large-scale study of mitochondrial DNA (mtDNA) and Y-chromosomal DNA variation in indigenous populations from these regions. Partial correlation coefficients, determined with Mantel tests, show that Y-chromosome variation in indigenous populations from the American Southwest and Mesoamerica correlates significantly with linguistic distances (r = 0.33-0.384; P < 0.02), whereas mtDNA diversity correlates significantly with only geographic distance (r = 0.619; P = 0.002). The lack of correlation between mtDNA and Y-chromosome diversity is consistent with differing population histories ofmales and females in these regions. Although unlikely, if groups of Uto-Aztecan speakers were responsible for the northward spread of agriculture and their languages from Mesoamerica to the Southwest, this migration was possibly biased tomales. However, a recent in situ population expansion within the American Southwest (2,105 years before present; 99.5% confidence interval = 1,273-3,773 YBP), one that probably followed the introduction and intensification of maize agriculture in the region, may have blurred ancient mtDNA patterns, which might otherwise have revealed a closer genetic relationship between females in the Southwest and Mesoamerica., Cited By (since 1996):16, CODEN: PNASA, ,
Author: Kemp, González-Oliver, Malhi, Monroe, Schroeder, McDonough, Rhett, Resendéz, Peñaloza-Espinosa, Buentello-Malo, Gorodesky, Smith
Date: 2010-01-01T00:00:00Z

Title: Age and growth studies of chondrichthyan fishes,
Description: Validated age and growth estimates are important for constructing age-structured population dynamic models of chondrichthyan fishes, especially those which are exploited. We review age and growth studies of chondrichthyan fishes, using 28 recent studies to identify areas where improvements can be made in describing the characteristics of ageing structures (both traditional and novel) utilized to estimate ages of sharks, rays, and chimaeras. The topics identified that need consistency include the: (1) terminology used to describe growth features; (2) methods used to both verify and validate age estimates from chondrichthyan calcified structures, especially edge and marginal increment analyses; and (3) the functions used to produce and describe growth parameters, stressing the incorporation of size at birth (L0) and multiple functions to characterize growth characteristics, age at maturity and longevity. © 2006 Springer Science+Business Media, Inc., Cited By (since 1996):76, Fish and Fisheries, CODEN: EBFID, ,
Author: Cailliet, Smith, Mollet, Goldman
Date: 2006-01-01T00:00:00Z

Title: Quantifying patterns of fish herbivory on Palmyra Atoll (USA), an uninhabited predator-dominated central Pacific coral reef
Description: On many coral reefs, herbivorous fish play an essential role in regulating algal growth and influencing the outcome of coral-algal competition. Working on a remote predator-dominated coral reef on Palmyra Atoll, USA, we used behavioral foraging observations to quantify the roles of common parrotfish and surgeonfish in the roving herbivore guild. We recorded species-specific bite rates on different benthic organisms, quantified the relative abundance of those benthic organisms, and estimated benthos-specific grazing intensities as a function of bite rates, fish abundance, and percent cover. These grazing metrics were compared between the exposed fore reef (∼10 m depth) and protected reef terrace (∼5 m depth) habitats. We observed large differences in feeding rates and substrate selectivity among fish species. Most species fed predominately on algal turfs; however, some species foraged broadly among fleshy macroalgal taxa, while others specialized on calcified green algae of the genus Halimeda. The highest bite rates were recorded from species targeting algal turfs, while the highest rates of defecation were recorded from species targeting Halimeda. Per capita bite rates of all species were higher in the fore reef habitat (mean 45% more bites min-1); however, overall grazing intensities on turf algae (bites cm-2 d-1) were 5 times higher on the reef terrace than on the fore reef. Despite habitat-specific differences in the herbivore assemblages, the estimated distribution of total bites showed consistency among habitats, with strong guild-level positive foraging selectivity for algal turf. Comparisons of bite and defecation rate data for these herbivores across the Indo-Pacific highlight phylogenetic constraints on grazing activities. Overall, this study illustrates the importance of herbivore functional redundancy, variability in species-specific grazing, and provides a framework for assessing guildwide grazing impacts on coral reefs. © Inter-Research 2014.
Author: Hamilton, Smith, Price, Sandin

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