Search results
(26 - 50 of 832)
Pages
- Title
- The relationship between water motion and living rhodolith beds in the southwestern Gulf of California, Mexico,
- Description
- Free living, nodular aggregates of non-geniculate coralline algae (rhodoliths) have occurred since the Cenozoic in diverse marine environments around the world. Fossil rhodolith morphology and distribution have been widely used as paleoecological indicators, particularly of water motion. However, few studies have verified these relationships in living beds. The relationship between water motion and rhodolith movement was examined in three subtidal rhodolith beds off the southwestern coast of the Gulf of California, one dominated by wave action and two dominated by tidal currents. Field experiments and simultaneous video and current measurements taken during winter 1996 showed that rhodoliths in the shallow margins (4.5 m depths) of wave-dominated beds moved frequently due to threshold-level velocities from wind-propagated waves. Rhodoliths did not move in the middle and at deep margins of the bed due to attenuation of wave energy. Historical wind records and waveforcasting analysis indicate that shallow rhodolith movement is frequent only in the winter. In deep tidally dominated beds, maximum yearly tidal currents were not sufficient to move rhodoliths. Video and SCUBA surveys showed that bioturbation is an important mechanism for rhodolith movement in all beds. Rhodoliths in 12-m-deep tidally dominated beds and in the deep margins of wave-dominated beds appear to move only occasionally due to bioturbation and severe storms. Results imply that rhodolith morphology and distribution are dependent on a combination of factors. These factors, especially bioturbation, should be considered when using rhodoliths as paleoecological indicators., Cited By (since 1996):66, ,
- Author
- Marrack
- Date
- 1999-01-01T00:00:00Z
- Title
- First account of steller sea lion (Eumetopias jubatus) predation on a California sea lion (Zalophus californianus),
- Description
- Cited By (since 1996):4, CODEN: MMSCE, , ,
- Author
- Byrnes, Hood
- Date
- 1994-01-01T00:00:00Z
- Title
- Effects of zoospore aggregation and substrate rugosity on kelp recruitment success,
- Description
- Successful kelp recruitment is important for kelp population persistence and associated kelp forest communities. The proximity of settled kelp zoospores is a known requirement for successful kelp recruitment and proximity can be increased as zoospores aggregate. Substrate rugosity can also be an important factor affecting macroalgal settlement and recruitment in wave-swept areas, and may affect kelp recruitment by aggregating zoospores. In this study, kelp zoospores were cultured at different levels of small-scale aggregation and kelp recruitment was quantified. Sporophyte production significantly increased as zoospores became more aggregated indicating that processes that aggregate kelp zoospores have the potential to enhance kelp recruitment. A 13-month field experiment demonstrated differential kelp recruitment onto settlement plates that mimicked surface rugosities of two common rock types within Stillwater Cove, Carmel Bay in central California (Carmelo Formation sandstone and Santa Lucia granodiorite). Significantly more kelp recruited to molds mimicking granodiorite over the yearlong study (granodiorite = 2.7 recruits ± SE 0.50, sandstone = 1.2 recruits ± SE 0.51). There was a significant difference in recruitment between seasons and this variability was due to the fact that spring had the highest average number of kelp recruits per mold. However, the interaction between substrate and season was not significant. This study emphasizes the importance of kelp zoospore aggregation on kelp recruitment and demonstrates that small-scale rugosity affects kelp recruitment. © 2012 Phycological Society of America., Cited By (since 1996):1, Seaweeds, CODEN: JPYLA, ,
- Author
- Muth
- Date
- 2012-01-01T00:00:00Z
- Title
- Corrigendum to "Total mercury body burden in Pacific harbor seal, Phoca vitulina richardii, pups from central California"
- Description
- Marine Mammals, Birds & Turtles Harbor Seals, CODEN: MPNBA
- Author
- Brookens, O'Hara, Taylor, Bratton, Harvey
- Date
- 2009-01-01T00:00:00Z
- 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
- 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
- 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
- Movement, dive behavior, and survival of California sea lions (Zalophus californianus) posttreatment for domoic acid toxicosis
- Description
- Domoic acid (DA) is a neuroexcitatory toxin increasingly causing strandings and mortality of marine mammals. The hippocampus of mammalian brains, associated with learning, memory, and spatial navigation, is one of the predominant regions affected by DA exposure. California sea lions stranding from 2003 to 2006 as a result of DA toxicosis were classified as having acute (n = 12) or chronic neurologic (n = 22) clinical signs. Chronic neurologic cases were examined by magnetic resonance imaging to determine the extent of brain damage related to DA exposure. Brain damage included hippocampal and parahippocampal atrophy, temporal horn enlargement, and pathological T2 hyperintensity. Posttreatment, animals were fitted with satellite transmitters and their movement and dive behaviors compared with those of a control group. The only significant difference between acute and chronic animals was distance traveled per day. There were, however, significant differences between chronic neurologic cases and controls: chronic neurologic cases dove shallower for shorter durations, traveled further from shore, and spent less time hauled out and more time surface swimming than control animals. There was no relationship between severity of brain damage and behavioral patterns for chronic neurologic cases. Sea lions with chronic neurologic changes had a poor prognosis for survival following release. © 2009 by the Society for Marine Mammalogy., Cited By (since 1996):6, CODEN: MMSCE
- Author
- Thomas, Harvey, Goldstein, Barakos, Gulland
- 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
- Rammed by the Exxon Valdez,
- Description
- , , ,
- Author
- Foster
- 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
- Potential prey resources for Marbled Murrelets in central California
- Description
- Information on the diet of the Marbled Murrelet, Brachyramphus marmoratus, in California is lacking. To assess availability of potential prey, we sampled small fishes at three locations in central California: Año Nuevo Bay, and two sites in northern Monterey Bay. These sites are used seasonally by Marbled Murrelets. Nearshore marine habitats were sampled with a midwater trawl during 2000, 2001, and 2002. We caught 36 taxa of demersal and midwater fish and cephalopods. Numerically dominant species at all sites were northern anchovy, Engraulis mordax, night smelt, Spirinchus starski, and white croaker, Genyonomus lineatus. The occurrence of these fishes concurrent with Marbled Murrelets provides information on potential prey available to Marbled Murrelets in central California., Cited By (since 1996):3
- Author
- Henkel, Harvey
- Title
- Damage and recovery in intertidal Fucus gardneri assemblages following the Exxon Valdez oil spill,
- Description
- Cited By (since 1996):19 Seaweeds, CODEN: MESED, In March 1989, the 'Exxon Valdez' spilled over 10 million gallons (ca 38 million I) of crude oil into Prince William Sound, Alaska , USA. The spill was followed by massive clean-up using hot seawater at high pressure as well as other mechanical and chemical techniques. We studied initial damage and subsequent recovery in the upper margin of the Fucus gardneri assemblage on protected shores by comparing sites that were unoiled, oiled and cleaned with hot water at high pressure, and oiled but less intensely cleaned. F. gardneri cover averaged 80% on unoiled sites but< 1 % on all oiled and cleaned sites 18 mo after the spill. The abundances of barnacles, littorine snails and limpets varied among sites and species, and this variation was associated in part with differences in their life histories. F. gardneri cover was still extremely low on oiled and cleaned sites 2.5 yr after the spill. Holdfasts that persisted after cleaning did not resprout. F. gardneri recruitment was lowest at intensely cleaned sites, and most recruits occurred in cracks near adults. Recruits were less abundant under adult canopies but placing canopies over recruits did not decrease their survivorship over 5 mo. Natural weathering of tar was rapid, with most marked patches gone in less than 1 yr. We conclude that intense mechanical cleaning following this oil spill increased damage and slowed recovery. Such methods should be avoided if reduction of environmental damage is the primary objective of post-spill management decisions. The recovery of F. gardneri at its upper margin might be enhanced by devices that retain moisture and increase substratum rugosity., ,
- Author
- Devogelaere, Foster
- Date
- 1994-01-01T00:00:00Z
- Title
- Proliferative responses of harbor seal (Phoca vitulina) T lymphocytes to model marine pollutants,
- Description
- In recent years, population declines related to viral outbreaks in marine mammals have been associated with polluted coastal waters and high tissue concentrations of certain persistent, lipophilic contaminants. Such observations suggest a contributing role of contaminant-induced suppression of cell-mediated immunity leading to decreased host resistance. Here, we assessed the effects of the prototypic polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (B[a]P), and two polychlorinated biphenyls (PCBs), CB-156 and CB-80, on the T-cell proliferative response to mitogen in harbor seal peripheral lymphocytes. Despite the variability associated with our samples from free-ranging harbor seals, we observed a clear suppressive effect of B[a]P (10 uM) exposure on T cell mitogenesis. Exposures to 10 uM CB-156 and CB-80, and 1.0 and 0.1 uM B[a]P, did not produce significant depression in lymphoproliferation. Exposure to the model PAH at 10 uM resulted in a 61% (range 34-97%) average reduction in lymphoproliferation. We were able to rule out a direct cytotoxic effect of B[a]P, indicating that observed effects were due to altered T cell function. Based on our in vitro results, we hypothesize that extensive accumulation of PAH by top-trophic-level marine mammals could alter T cell activation in vivo and impaired cell-mediated immunity against viral pathogens., Cited By (since 1996):12, CODEN: DEIME, ,
- Author
- Neale, Van De Water, Harvey, Tjeerdema, Gershwin
- Date
- 2002-01-01T00:00:00Z
- 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