Search results

Title: The level of agreement among experts applying best professional judgment to assess the condition of benthic infaunal communities,
Description: Benthic infaunal communities are frequently used to assess aquatic environmental condition, but interpretation of benthic data is often subjective and based on best professional judgment. Here, we examine the repeatability of such assessments by providing species-abundance data from 35 sites to 9 independent benthic experts who ranked the sites from best to worst condition. Their site rankings were highly correlated, with an average correlation coefficient of 0.91. The experts also evaluated the sites in terms of four condition categories: (1) unaffected, (2) marginal deviation from reference, (3) affected, or (4) severely affected. At least two-thirds of the experts agreed on site categorization for 94% of the samples and they disagreed by more than one category for less than 1% of the assessment pairs. The experts identified seven parameters used in making their assessments, with four of those parameters (dominance by tolerant taxa, presence of sensitive taxa, species richness, and total abundance) used by all of the experts. Most of the disagreements in site categorization were due to philosophical rather than technical differences, such as whether the presence of invasive species indicates a degraded community. Indices are increasingly being used as an alternative to best professional judgment for assessing benthic condition, but there have been inconsistencies in how sites are selected for validating such indices; the level of agreement found among experts in this study suggests that consensus expert opinion can be a viable benchmark for such evaluations. © 2007 Elsevier Ltd. All rights reserved., Cited By (since 1996):29, Invertebrates, ,
Author: Weisberg, Thompson, Ranasinghe, Montagne, Cadien, Dauer, Diener, Oliver, Reish, Velarde, Word
Date: 2008-01-01T00:00:00Z

Title: Introduction to the systematics and biodiversity of sharks, rays, and chimaeras (Chondrichthyes) of Taiwan
Description: All 13 orders of chondrichthyan fishes occur in Taiwanese waters, representing 52 chondrichthyan families (31 shark, 19 batoid, 2 chimaeroid) and 98 genera (64 shark, 31 batoid, 3 chimaeroid). A total of 119 shark, 58 batoid, and 4 chimaera species may occur in the waters surrounding Taiwan, pending taxonomic resolution of some groups. Of the 34 nominally described species from Taiwan, 17 are currently considered valid. The majority of named species occurred during two peak periods in Taiwanese chondrichthyan research; the first between 1959-63, when 13 nominal species were described, of which 7 remain valid today, and a second peak period between 2003-13 when 9 nominal species were described, of which 6 remain valid. The overall species diversity of Taiwan's chondrichthyan fauna is comparable to that of other adjacent marine zoogeographic hotspots, e.g. Japan (126 shark, 75 batoid, 11 chimaeroid species) and the Philippines (81 shark, 46 batoid, 2 chimaeroid species). The Carcharhiniformes, Squaliformes, Myliobatiformes, and Rajiformes are the most dominant orders in terms of abundance and species-richness within this region. Each of these groups may increase in relative diversity with improved taxonomic resolution resulting from the incorporation of molecular tools and renewed morphological studies. Improved identification of Taiwan's chondrichthyan fauna will aid in developing better conservation and management practices. © 2013 Magnolia Press., Export Date: 11 February 2014, Source: Scopus
Author: Ebert, Ho, White, De Carvalho
Date: 2013-01-01T00:00:00Z

Title: A new species of Malthopsis (Lophiiformes: Ogcocephalidae) from the western Atlantic Ocean,
Description: A new species of Malthopsis is described from the western Atlantic Ocean, the first Malthopsis known from anywhere outside the Indo-western Pacific region except for Hawaii. Of 25 depth records, all were 275-475 m except one, which was 91 m., Cited By (since 1996):4, CODEN: BMRSA, , , Fish and Fisheries
Author: Bradbury
Date: 1998-01-01T00:00:00Z

Title: The effects of Cu on the adenylate energy charge of open ocean phytoplankton,
Description: The effects of short-term, acute Cu exposure (6 h) on the adenylate energy charge (EC A) of open-ocean phytoplankton populations (northeastern equatorial Pacific) were investigated. Energy charge remained at ̃0.77 over the range of Cu additions (0.025 - 5.μg l -1), even though 14C uptake and total adenylate levels (ATP + ADP + AMP) were reduced by as much as 60%. These findings suggest that EC A alone is not a sensitive indicator of acute sublethal metal effects on phytoplankton. © 1983 IRL Press Ltd., Cited By (since 1996):1, Oceanography, CODEN: JPLRD, ,
Author: Fitzwater, Knauer, Martin
Date: 1983-01-01T00:00:00Z

Title: Assessment of MERIS reflectance data as processed with SeaDAS over the European seas,
Description: The uncertainties associated with MERIS remote sensing reflectance (R RS) data derived from the SeaWiFS Data Analysis System (SeaDAS) are assessed with field observations. In agreement with the strategy applied for other sensors, a vicarious calibration is conducted using in situ data from the Marine Optical BuoY offshore Hawaii, and leads to vicarious adjustment factors departing from 1 by 0.2% to 1.6%. The three field data sets used for validation have been collected at fixed stations in the northern Adriatic Sea and the Baltic Sea, and in a variety of European waters in the Baltic, Black, Mediterranean and North Seas. Excluding Baltic waters, the mean absolute relative difference |Psi;| between satellite and field data is 10-14% for the spectral interval 490-560 nm, 16-18% at 443 nm, and 24-26%at413 nm. In the Baltic Sea, the |Psi;| values are much higher for the blue bands characterized by low RRS amplitudes, but similar or lower at 560 and 665 nm. For the three validation sets, the root-mean-square differences decrease from approximately 0.0013 sr -1 at 413 nm to 0.0002 sr -1 at 665 nm, and are found similar or lower than those obtained for SeaWiFS or MODIS-Aqua. As derived from SeaDAS, the RRS records associated with these three missions thus provide a multi-mission data stream of consistent accuracy. © 2011 Optical Society of America., Cited By (since 1996):4, Oceanography, ,
Author: Mélin, Zibordi, Berthon, Bailey, Franz, Voss, Flora, Grant
Date: 2011-01-01T00:00:00Z

Title: Characterizing source sink dynamics with genetic parentage assignments,
Description: Source-sink dynamics have been suggested to characterize the population structure of many species, but the prevalence of source-sink systems in nature is uncertain because of inherent challenges in estimating migration rates among populations. Migration rates are often difficult to estimate directly with demographic methods, and indirect genetic methods are subject to a variety of assumptions that are difficult to meet or to apply to evolutionary timescales. Furthermore, such methods cannot be rigorously applied to high-gene-flow species. Here, we employ genetic parentage assignments in conjunction with demographic simulations to infer the level of immigration into a putative sink population. We use individual-based demographic models to estimate expected distributions of parent-offspring dyads under competing sink and closed-population models. By comparing the actual number of parent-offspring dyads (identified from multilocus genetic profiles) in a random sample of individuals taken from a population to expectations under these two contrasting demographic models, it is possible to estimate the rate of immigration and test hypotheses related to the role of immigration on population processes on an ecological timescale. The difference in the expected number of parent-offspring dyads between the two population models was greatest when immigration into the sink population was high, indicating that unlike traditional population genetic inference models, the highest degree of statistical power is achieved for the approach presented here when migration rates are high. We used the proposed genetic parentage approach to demonstrate that a threatened population of Marbled Murrelets (Brachyramphus marmotus) appears to be supplemented by a low level of immigration (∼2-6% annually) from other populations. © 2008 by the Ecological Society of America., Cited By (since 1996):20, Marine Mammals, Birds & Turtles, CODEN: ECOLA, ,
Author: Peery, Beissinger, House, Bérubé, Hall, Sellas, Palsbøll
Date: 2008-01-01T00:00:00Z

Title: Diet, feeding behaviour and habitat utilisation of the blue stingray Dasyatis chrysonota (Smith, 1828) in South African waters,
Description: Analysis of stomach contents for Dasyatis chrysonota revealed that diet varied with size and habitat. The diet of all size classes in the surf zone was comprised primarily of Callianassa spp., Donax spp. and unidentified polychaete species. The medium and large size classes fed primarily on Donax spp., whereas the very large size class fed mainly on Callianassa spp. Polychaetes were of secondary importance as prey for the medium size class. The diet of D. chiysonota in the nearshore zone consisted mainly of Balanoglossus capensis and Callianassa spp. Balanoglossus capensis decreased from an index of relative importance (IRI) of 75.3% for the medium size class to 59.9% for the very large size class, whereas Callianassa spp. increased from 22.8% to 39.4% between the medium and the very large size classes. The offshore zone was the only area in which small size class D. chrysonota were caught. The diet of these small D. chrysonota was primarily polychaetes and amphipods. Polychaetes increased in importance in the medium size class, but declined in each successively larger size class. Conversely, Pterygosquilla armata capensis became the single most important prey item for the very large size class, comprising an IRI of 50.9%. The behaviour pattern used by D. chrysonota to locate and extract prey is described., Cited By (since 1996):27, Fish and Fisheries, CODEN: AJMFA, ,
Author: Ebert, Cowley
Date: 2003-01-01T00:00:00Z

Title: Comparison of seastar (Asteroidea) fauna across island groups of the Scotia Arc,
Description: The Antarctic shelf fauna is isolated from other continental shelf faunas both physically by distance, and oceanographically by the Antarctic circumpolar current (ACC). To elucidate the relative importance of these two isolating mechanisms, we used the seastar fauna of the south-Atlantic sub-Antarctic islands to address the hypothesis that the ACC is dominant in controlling the distribution pattern of Antarctic fauna. We expected that seastar faunas from islands on the high latitude side of the ACC would show more similarities to each other than to faunas from islands on the low latitude side. The alternative isolation by distance model predicted that the island furthest from others would have the most unique fauna. For shelf-depth (<500 m) Asteroidea of the Scotia Arc region, assemblages were more similar between islands on each side of the ACC barrier than islands that were closer together, and this pattern was caused by differences in abundance of a few ubiquitous species. © 2006 Springer-Verlag., Cited By (since 1996):3 Invertebrates, ,
Author: Kim, Thurber
Date: 2007-01-01T00:00:00Z

Title: Genetic patterns across multiple introductions of the globally invasive crab genus Carcinus,
Description: The European green crab Carcinus maenas is one of the world's most successful aquatic invaders, having established populations on every continent with temperate shores. Here we describe patterns of genetic diversity across both the native and introduced ranges of C. maenas and its sister species, C. aestuarii, including all known non-native populations. The global data set includes sequences from the mitochondrial cytochrome c oxidase subunit I gene, as well as multilocus genotype data from nine polymorphic nuclear microsatellite loci. Combined phylogeographic and population genetic analyses clarify the global colonization history of C. maenas, providing evidence of multiple invasions to Atlantic North America and South Africa, secondary invasions to the northeastern Pacific, Tasmania, and Argentina, and a strong likelihood of C. maenas x C. aestuarii hybrids in South Africa and Japan. Successful C. maenas invasions vary broadly in the degree to which they retain genetic diversity, although populations with the least variation typically derive from secondary invasions or from introductions that occurred more than 100 years ago., Cited By (since 1996):54, CODEN: MOECE, ,
Author: Darling, Bagley, Roman, Tepolt, Geller
Date: 2008-01-01T00:00:00Z

Title: Sedimentation and composition of wall communities in Alaskan fjords,
Description: The effects of suspended sediments on the composition of wall communities in Alaskan fjords were investigated by quantitative assessment of underwater photo-quadrats. In fjords with actively retreating tidewater glaciers, suspended sediment levels were extremely high at the heads and were exponentially lower at the mouths. Fjords without glaciers had low suspended sediment levels throughout. The per cent cover and number of species were lowest where sedimentation was highest, at the heads of glacial fjords. Here the wall communities were dominated by a sparse cover of small serpulid worms. Richer communities comprising mostly algae, sponges, hydroids, bryozoans, tunicates and brachiopods were found in fjords without glaciers, and at the mouths of glacial fjords. There was a positive correlation between water clarity and community composition along a gradient from heads to the mouths of fjords with high suspended sediment levels., Cited By (since 1996):3, Invertebrates, Ecology, CODEN: POBID, ,
Author: Carney, Oliver, Armstrong
Date: 1999-01-01T00:00:00Z

Title: Dissolved oxygen dynamics in a eutrophic estuary, Upper Newport Bay, California,
Description: Eutrophication often causes hypoxia in estuarine and coastal systems, but the mechanisms that control hypoxic events vary among estuaries and are often difficult to discern. We monitored surface and bottom dissolved oxygen (DO) in the Upper Newport Bay (UNB), a tidally mixed estuary in southern California subject to anthropogenic nutrient loading, eutrophication and hypoxia. Our goal was to identify the environmental factors regulating DO dynamics. Six hypoxic events occurred between June and November and were associated with a combination of low solar radiation, increased freshwater discharge following precipitation, and enhanced haline stratification during reduced tidal range periods. At the head of the estuary, high macroalgal biomass and pronounced haline stratification resulted in high DO in the surface layer and low DO in the bottom layer. Oxygen-rich and oxygen-poor waters were transported down-estuary by ebb tides, resulting in DO heterogeneity throughout the UNB. Cross-wavelet analysis illustrated the down-estuary propagation of high/low DO signal correlated with the phases of diurnal photosynthetic and semi-diurnal tidal cycles. © 2009 Elsevier Ltd. All rights reserved., Cited By (since 1996):10, Oceanography, CODEN: ECSSD, ,
Author: Nezlin, Kamer, Hyde, Stein
Date: 2009-01-01T00:00:00Z

Title: A revision of the western North Pacific swellsharks, genus Cephaloscyllium Gill 1862 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), including descriptions of two new species.,
Description: The genus Cephaloscyllium Gill 1862 (Chondrichthyes, Carcharhiniformes, Scyliorhinidae) until recently had only two species recognized, C. isabellum [= C. umbratile (Jordan & Fowler 1903)] and C. fasciatum Chan 1966, from the western North Pacific (WNP), with one dubious species, C. formosanum, having been described by Teng in 1962. Recently, three additional species were described, C. circulopullum Yano et al. 2005, C. sarawakensis Yano et al. 2005, and C. parvum Inoue & Nakaya 2006 from this region. Here we present a revision of this genus for the WNP, including redescriptions of C. fasciatum and C. umbratile based on the holotypes, a re-examination of the recently described species, and descriptions of two new species from Taiwan. Cephaloscyllium umbratile can be distinguished from its congeners based on maximum size, length of first dorsal-fin base, anal-caudal space, and dorsal-caudal space. We conclude, based on a comparison of C. parvum and C. sarawakensis, that the former is a junior synonym of the latter species. The two new Taiwanese species can be separated from other WNP species by color pattern, shape of the anterior nasal flap, anal and dorsal-fin size, internarial width, and mouth size. Finally, we present a revised dichotomous key to the WNP Cephaloscyllium recognizing six contemporary taxa: C. circulopullum, C. fasciatum, C. sarawakensis, C. umbratile, C. pardelotum sp. nov. and C. maculatum sp. nov. Copyright © 2008 Magnolia Press., Cited By (since 1996):2, , , Fish and Fisheries
Author: Schaaf-Da Silva, Ebert
Date: 2008-01-01T00:00:00Z

Title: Improvement of the pre-deployment net closure procedure used with opening/closing plankton nets,
Description: The construction of a closing device to be used during the deployment of phyto-zooplankton nets utilizing General Oceanics-type opening/closing mechanisms is described. This device (the cowl) decreases system set-up time, decreases contamination from ambient particles while waiting for deployment, protects the net from mechanical tears during descent, and increases system reliability., Cited By (since 1996):2, CODEN: JPLRD, ,
Author: Tuel, Knauer
Date: 1982-01-01T00:00:00Z

Title: The tail of the Storegga Slide: Insights from the geochemistry and sedimentology of the Norwegian Basin deposits
Description: Deposits within the floor of the Norwegian Basin were sampled to characterize the deposition from the Storegga Slide, the largest known Holocene-aged continental margin slope failure complex. A 29 to 67 cm thick veneer of variable-coloured, finely layered Holocene sediment caps a homogeneous, extremely well-sorted, poorly consolidated, very fine-grained, grey-coloured sediment section that is >20 m thick on the basin floor. This homogeneous unit is interpreted to represent the uppermost deposits generated by a gravity flow associated with the last major Storegga Slide event. Sediments analogous to the inferred source material of the slide deposits were collected from upslope on the Norwegian Margin. Sediments sampled within the basin are distinguishable from the purported source sediments, suggesting that size sorting has significantly altered this material along its flow path. Moreover, the very fine grain size (3·1 ± 0·3 μm) suggests that the >20 m thick homogeneous unit which was sampled settled from suspension after the turbulent flow was over. Although the turbulent phase of the gravity flow that moved material out into the basin may have been brief (days), significantly more time (years) is required for turbid sediments to settle and dewater and for the new sea floor to be colonized with a normal benthonic fauna. Pore water sulphate concentrations within the uppermost 20 m of the event deposit are higher than those normally found in sea water. Apparently the impact of microbial sulphate reduction over the last ca 8·1 cal ka bp since the re-deposition of these sediments has not been adequate to regenerate a typical sulphate gradient of decreasing concentration with sub-bottom depth. This observation suggests low rates of microbial reactions, which may be attributed to the refractory carbon composition in these re-deposited sediments. © 2010 The Authors. Journal compilation © 2010 International Association of Sedimentologists., Cited By (since 1996):1, Rocks & Cores
Author: Paull, Ussler III, Holbrook, Hill, Haflidason, Winters, Lorenson, Aiello, Johnson, Lundsten
Date: 2010-01-01T00:00:00Z

Title: Energetic composition, biomass, and chemical defense in the common Antarctic nemertean Parborlasia corrugatus McIntosh,
Description: Parborlasia corrugatus McIntosh is a large, abundant, epibenthic antarctic nemertean which represents a considerable source of nutrition for predators. The energetic composition of adult body tissues (kJ·g -1 dry wt) is comprised primarily of energy derived from protein (11.4 kJ NaOH-insoluble, 6 kJ NaOH-soluble). Energy units associated with lipid (4.3 kJ) and carbohydrate (0.2 kJ) are much lower. Based on calculations of the energetic composition of whole body tissues, and a density of 0.3 ind·m -2, mean population energetic density is estimated to be 65 kJ·m -2. These values are often significantly higher as P. corrugatus aggregates when feeding. Despite their high abundance, nemerteans are not preyed upon and appear to be chemically defended. Sperm of the antarctic sea urchin Sterechinus neumeyeri (Meissner) were killed when exposed to a 3% aqueous extract of whole nemertean body tissues. In laboratory feeding experiments, two common species of antarctic fish showed significant rejection of nemerteans. Its toxic and feeding-deterrent characteristics are probably the result of the epithelial production of copious acidic mucus (pH = 3.5), although other toxic or noxious metabolites may be present. These results indicate that P. corrugatus, an important scavenger in antarctic benthic systems, is abundant, high in nutrients and energy content, and could be judged on this basis as a high-quality prey item. Nonetheless, due to its chemical defense, potential predators may avoid ingestion of this species., Cited By (since 1996):28, Invertebrates, Antarctica, CODEN: JEMBA, ,
Author: Heine
Date: 1991-01-01T00:00:00Z

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: Chlamydoselachus africana, a new species of frilled shark from southern Africa (Chondrichthyes, Hexanchiformes, Chlamydoselachidae),
Description: Frilled sharks (Chondrichthyes, Hexanchiformes, Chlamydoselachidae), long believed to be a monotypic family and genus, consisting of a single wide ranging species, Chlamydoselachus anguineus (Garman, 1884), is now known to contain at least two species. A new species of frilled shark, Chlamydoselachus africana, sp. nov., is described from five specimens collected from southern Africa. The new species, although difficult to distinguish externally from the well known C. anguineus, differ internally by the structural differences in the chondrocranium, lower total vertebral and spiral valve counts, and pectoral-fin radial counts. The new species, Chlamydoselachus africana, is known from off southern Angola, Namibia, and South Africa. © 2009 · Magnolia Press., Cited By (since 1996):3, Fish and Fisheries, ,
Author: Ebert, Compagno
Date: 2009-01-01T00:00:00Z

Title: Abundance, seasonal distribution and population composition of balaenopterid whales in the Canal de Ballenas, Gulf of California, Mexico,
Description: Blue whales Balaenoptera musculus were most abundant in April and May while minke B. acutorostrata whales were equally abundant throughout the year. Fin B. physalus and Bryde's whales B. edeni were found but fin whales were more abundant in winter and spring; numbers were negatively correlated with water temperature. Bryde's whales were more abundant in summer and fall; numbers were positively correlated with water temperature. The percentage of identified individual adults that were females with calves was 10.6 for Bryde's and 2.7 for fin whales., Cited By (since 1996):13, , , Marine Mammals, Birds & Turtles
Author: Tershy, Breese, Strong
Date: 1990-01-01T00:00:00Z

Title: A review of apparent 20th century changes in the presence of mussels (Mytilus trossulus) and macroalgae in Arctic, Alaska, and of historical and paleontological evidence used to relate mollusc distributions to climate change
Description: Live mussels attached to fresh laminarioid brown algae, all fastened to clusters of pebbles and small cobbles, were repeatedly cast ashore by autumn storms at Barrow, Alaska, in the 1990s. Specimens of Laminaria saccharina and L. solidungula shorten by 100 km a 500 km gap (Peard Bay to Stefansson Sound) between previously known concentrations of these kelp species. For the genus Mytilus, a 1 600 km gap in fully documented locations existed between Kivalina in the southern Chukchi Sea and the Mackenzie River delta. Barrow specimens were identified using a mitochondrial DNA marker as M. trossulus, an identity consistent with dispersal from the Pacific-Bering side of the Arctic. Live mussels and macroalgae were neither washed up by storms nor collected by active biological sampling during extensive benthic surveys at Barrow in 1948-50. We cannot interpret the current presence of these bivalves and macrophytes as Arctic range extensions due to warming, similar to those manifested by the tree line in terrestrial systems and by Pacific salmon in marine environments. Supplemental information and critical evaluation of survey strategies and rationales indicate that changes in sea temperatures are an unlikely cause. Alternative explanations focus on past seafloor disturbances, dispersal from marine or estuarine refugia, and effects of predators on colonists. This review suggests refining some interpretations of environmental change that are based on the extensive resource of Cenozoic fossils of Arctic molluscs., Cited By (since 1996):16, CODEN: ATICA, Invertebrates
Author: Feder, Norton, Geller
Date: 2003-01-01T00:00:00Z

Title: Benthic manganese fluxes along the Oregon-California continental shelf and slope
Description: Here we examine the factors that influence the manganese (Mn) benthic flux from eastern North Pacific marine sediments, with a primary emphasis on continental shelf locations off Oregon and California and studies that involve the use of in situ benthic chambers. Typical shelf-to-shallow margin (<~350m) sites have benthic Mn efflux rates that average ~8±5μmolm-2d-1. In contrast, for the Eel River continental shelf region the benthic Mn efflux can be an order of magnitude higher than other shelf settings with benthic effluxes exceeding ~50μmolm-2d-1. Based on prior work and some new results, continental margin and slope sites (350-~4000m) have benthic Mn efflux rates that average ~1±1μmolm-2d-1. The combination of the benthic flux and Mn solid-phase data, indicate that for the continental shelf off the Umpqua and Eel Rivers, approximately 15±10% of the total Mn that is delivered to the seafloor is remobilized. The compiled data set shows that the benthic Mn efflux co-varies with the organic carbon oxidation rate with a Mn to organic carbon oxidation (Cox) ratio of ~0.8mmol Mn mol-1. Although this ratio can be as high as ~5 for some Eel River sites, the generally close correspondence between Mn and organic carbon implies that the organic carbon oxidation rate exerts some primary control over the rate of the Mn efflux. The amount of organic carbon oxidized by Mn-oxides, however, represents a small fraction (i.e., generally <1%) of the total organic carbon oxidized in these seafloor sediments. © 2012 Elsevier Ltd., Cited By (since 1996):5, Oceanography, CODEN: CSHRD
Author: McManus, Berelson, Severmann, Johnson, Hammond, Roy, Coale
Date: 2012-01-01T00:00:00Z

Title: Isotopic tracers of lead contamination in the Great Lakes,
Description: , , , Fluxes of lead to the Great Lakes are dominated by atmospheric depositions of industrial lead, which account for ~ 64% of the lead inputs to Lake Ontario and >90% of the inputs to Lake Superior. It has recently been demonstrated that lead aerosols in the Great Lakes region may be identified by the contrasting 206Pb/207Pb ratios of industrial leads from the United States (1.221 ±0.009) and Canada (1.151 ±0.010). Here we show that those ratios may also be used to identify and trace industrial lead inputs to the Great Lakes. These corroborate spatial gradients in lead concentrations in surface waters, which range from 290 pmol kg−1 in Hamilton Harbour to <10 pmol kg−1 in the central waters of Lake Ontario. The latter concentrations and corresponding residence-time estimates, which are both an order of magnitude lower than previously reported, indicate that lead is rapidly scavenged in the epilimnion during periods of high primary productivity. We find that industrial lead from Canada and the United States are the two principal sources of lead contamination in the Great Lakes., ,
Author: Flegal, Nriagu, Niemeyer, Coale
Date: 1989-01-01T00:00:00Z

Title: Assessing mercury exposure and biomarkers in largemouth bass (Micropterus Salmoides) from a contaminated river system in California
Description: We evaluated mercury (Hg) exposure and two biomarkers, metallothionein (MT) gene expression and histopathological alterations in a wild fish species, largemouth bass (Micropterus salmoides), collected from the Sacramento-San Joaquin Delta, CA, a region polluted with Hg from historic mining activities. Hg is highly toxic and can disrupt multiple physiological systems in vertebrate species, including the immune system. Total mercury (THg) concentration in muscle tissue ranged from 0.12 to 0.98 ppm (wet weight) and was not related to body condition (r 2 = 0.005, p = 0.555). Using linear regression analysis, we found a positive relationship between MT gene expression (as determined using quantitative polymerase chain reaction) and copper, zinc, manganese, aluminum, and nickel (decreased to one variable by way of principal component analysis) (r 2 = 0.379, p = 0.044), a negative relationship with selenium (r 2 = 0.487, p = 0.017), and a weak, negative relationship with THg concentrations (r 2 = 0.337, p = 0.061). Juvenile largemouth bass collected from Hg-contaminated areas displayed histopathological features of immunosuppression compared with those collected from less contaminated areas as evidenced by significantly lower macrophage density in kidney and liver tissue (p = 0.018 and 0.020, respectively), greater trematode density in liver tissue (p = 0.014), and a greater number of adult trematodes. Our results suggest that largemouth bass may be experiencing sublethal effects from chronic Hg exposure. Furthermore, our findings illustrate the utility of examining multiple sublethal markers of effect to assess the impacts of contaminant exposure on physiological function in wild species. © 2012 Springer Science+Business Media New York., Fish and Fisheries, CODEN: AECTC
Author: Gehringer, Finkelstein, Coale, Stephenson, Geller
Date: 2013-01-01T00:00:00Z

Title: Size at first reproduction of the sea urchin Strongylocentrotus purpuratus in a central California kelp forest,
Description: Most individuals 16 mm and larger at Stillwater Cove, Carmel Bay, were mature. -from Authors, Cited By (since 1996):4, Invertebrates, , , Downloaded from:www.int-res.com/articles/meps/76/m076p303.pdf (16 June 2014).
Author: Kenner, Lares
Date: 1991-01-01T00:00:00Z

Title: Broad-scale factors influencing the biodiversity of coastal benthic communities of the Ross Sea,
Description: Early ecological research in McMurdo Sound revealed local spatial gradients in community structure associated with variations in anchor ice disturbance, fast ice and snow cover, and the effects of predators. Research contrasting the east and west sides of McMurdo Sound has shown major differences in benthic communities, which have been attributed to oceanographic influences on the advection of water-column productivity and the frequency of fast ice break-out. Despite these regional and local differences, coastal benthic communities in McMurdo Sound show a high level of stability, and contain a variety of large and potentially very long-lived species. In Terra Nova Bay, about half way along the Victoria Land Coast of the western Ross Sea, the coastal benthic communities provide some insightful contrasts with those in McMurdo Sound. For example, the abundance and depth distribution of dominant species such as Sterechinus neumayeri and Adamussium colbecki are markedly different from McMurdo Sound. In both locations communities dominated by large sponges are most prolific in regions that are free from iceberg disturbance of the seabed. A recent assessment of northern Victoria Land coastal benthic communities, in conjunction with multibeam imagery of the seafloor, further highlights the importance of iceberg disturbance in structuring Antarctic benthic communities. A comparative synthesis of these coastal ecological studies enables us to generate hypotheses concerning the relative importance of different environmental drivers in structuring benthic communities. Overlain on the regular latitudinal shifts in physical factors such as light regime, are regional fluctuations that are controlled by atmospheric and oceanographic circulation patterns and coastal topography/bathymetry. Change in diversity along the western coast of the Ross Sea is predicted to be influenced by three main factors (1) ice disturbance (e.g., via anchor ice and advection of supercooled water or icebergs), (2) photosynthetically available radiation (affected by ice and snow cover and water clarity), (3) the locations of polynyas and advection of planktonic production and larvae. Interactions between these factors are expected to result in non-linear changes along the latitudinal gradient. While predictions generated from these hypotheses remain to be rigorously tested, they provide indications of how benthic communities may respond to changes in production, disturbance and the stability of coastal sea ice. © 2006 Elsevier Ltd. All rights reserved., Cited By (since 1996):28, Invertebrates, CODEN: DSROE, ,
Author: Thrush, Dayton, Cattaneo-Vietti, Chiantore, Cummings, Andrew, Hawes, Kim, Kvitek, Schwarz
Date: 2006-01-01T00:00:00Z

Title: Distribution and abundance of larval fishes collected in the western Bransfield Strait region, 1986-87,
Description: Larval fishes were obtained from 0-50 m Bongo net and stratified 0-200 m Nansen net samples collected in the western Bransfield Strait region during four RACER (Research on Antarctic Coastal Ecosystem Rates) program cruises, December 1986 to March 1987. Three nototheniid species, Nototheniops larseni, Notothenia gibberifrons, and a form tentatively identified as Tremtomus scotti numerically dominated the total catch. Two typically abundant species in this area, Pleuragramma antarcticum and Notothenia kempi, were relatively uncommon. Gear differences, the restricted geographical coverage, and between-year variability in hydrographic conditions may explain species dominance differences between the RACER samples and prior surveys in the Antarctic Peninsula area. Largest abundances occurred in the vicinity of Gerlache Strait and island shelf areas; larvae were infrequently collected in Drake Passage waters. Individual species demonstrated different distributional patterns, suggesting that water mass influence, larval depth distribution and behavioral differences may be involved. Estimated January to March growth rates for N. larseni (0.06 mm day-1) and T. scotti (0.05 mm day-1) are similar but low compared to that of N. gibberifrons (0.12 mm day-1). © 1991., Cited By (since 1996):12, Antarctica, Fish and Fisheries, ,
Author: Loeb
Date: 1991-01-01T00:00:00Z

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