National Ocean Service

About: National Ocean Service is a government organization based out in Silver Spring, Maryland, United States. It is known for research contribution in the topics: Algal bloom & Population. The organization has 500 authors who have published 643 publications receiving 46096 citations.

Influence of nutritional state on the progression and severity of mycobacteriosis in striped bass Morone saxatilis.

Abstract: Challenge studies with Mycobacterium marinum clearly demonstrate that a poor diet affects the progression and severity of mycobacteriosis in striped bass Morone saxatilis. Fish (n = 512 total, wt = 65 +/- 15 g) were inoculated intraperitoneally with 10(4) colony-forming units (CFU) g(-1) body weigth (BW) or a physiological saline solution (controls) and evaluated for 8 mo. Inoculated fish fed a low-ration diet (0.15% BW d(-1)) developed a severe, systemic infection characterized by a high bacterial load (>10(8) CFU g(-1) spleen) and poor granuloma formation, which commonly progressed to mortality by 6 wk. In contrast, inoculated fish fed an adequate ration diet (1% BW d(-1)) developed classic granulomatous inflammation of reduced severity and total body energy similar to that found in uninoculated controls (p > 0.05). After 4 wk, fish fed adequate rations maintained an equilibrium state throughout the study period, even though 10(6) CFU g(-1) spleen mycobacteria were consistently cultured. In a second study, reactivation of an acute inflammatory state was demonstrated by placing previously infected fish on reducing diets (0.073% BW d(-1)). In both studies, the energetic demand of this disease was only appreciable when associated with active, severe, inflammatory states. To our knowledge, this study is the first to demonstrate the interaction of diet and mycobacteriosis in fish.

Ocean Circulation and Water Mass Characteristics around the Galápagos Archipelago Simulated by a Multiscale Nested Ocean Circulation Model

Abstract: Ocean circulation and water mass characteristics around the Galapagos Archipelago are studied using a four-level nested-domain ocean system (HYCOM). The model sensitivity to atmospheric forcing frequency and spatial resolution is examined. Results show, that with prescribed atmospheric forcing, HYCOM can generally simulate the major El Nino events especially the strong 1997-1998 events. Waters surrounding the archipelago show a large range of temperature and salinity in association with four different current systems. West zones of Isabella and Fernandina Islands are the largest upwelling zones, resulting from the collision of the Equatorial Undercurrent (EUC) with the islands, bringing relatively colder, salty waters to the surface and marking the location of the highest biological production. Model results, which agree well with observations, show a seasonal cycle in the transport of the EUC, reaching a maximum during the late spring/early summer and minimum in the late fall. The far northern region is characterized by warmer, fresher water with the greatest mixed layer depth as a result of Panama Current waters entering from the northeast. Water masses over the remainder of the region result from mixing of cool Peru Current waters and upwelled Cold Tongue waters entering from the east.

Phytoplankton blooms detected by SeaWiFS along the central and southern California coast

Abstract: [1] The effect of upwelling events, storm water discharge, and local circulation on phytoplankton blooms in the central California and Southern California Bight (SCB) coastal zones was analyzed using 10+ years (1997–2007) of remotely sensed surface chlorophyll concentration (CHL, derived from SeaWiFS ocean color), sea surface temperature, and modeled freshwater discharge. Analysis of variability and factors associated with phytoplankton blooms was conducted using the offshore extension of zones of CHL > 5 mg m−3; this method excludes terrestrial interference that complicates the use of ocean color to investigate phytoplankton blooms in coastal waters. In the SCB, blooms were most frequent in spring and associated with the spring transition to an upwelling regime. Along the Central Coast, blooms persisted from spring to autumn during seasonal intensification of upwelling. Offshore CHL extensions showed a significant positive trend during 1997–2007, with maxima in 2000–2001 and 2005–2006 that coincided with higher than normal frequency of upwelling events. Upwelling was found to be a major factor driving phytoplankton blooms, although the standard upwelling index derived from large-scale atmospheric circulation was decoupled from the frequencies of both upwelling events and phytoplankton blooms. Areas of longer residence time associated with natural boundaries between coastal ocean regions had more extensive and persistent blooms. The influence of storm water discharge on offshore CHL extension appeared to be limited to areas in close proximity to major river mouths. These “hot spots” were also co-located with ocean outfalls of Publicly Owned Treatment Works (POTW) discharge and, in some cases, longer residence time of coastal waters.

Toxicity of saline and organic solvent extracts of sediments from Boston Harbor, Massachusetts and the Hudson River-Raritan Bay estuary, New York using the Microtox® bioassay

Abstract: The toxic effects of organic and saline extracts of sediment samples collected from 16 sites in Boston Harbor, Massachusetts and from 17 sites in the Hudson River-Raritan Bay estuary, New York were tested with the Microtox® bioassay. This bioassay measures changes in light production by bioluminescent marine bacteria exposed to sediment extracts. Organic solvent extracts of all 33 sediments showed some degree of toxicity, with sediment samples from sites in the urban areas of the bays being significantly more toxic than those from less urbanized areas of the bays. Saline extracts, however, were less toxic, only seven of 33 saline extracts produced a significant response using the recommended method of data analyses. The proportional decrease in bacterial light production at the highest concentration of saline sediment extract in the reaction mixture compared to the bacterial light production in the controls (saline light change—SLC) appeared to be a better indicator of sediment toxicity than generating a saline EC50 (the amount of sediment required to reduce bioluminescence 50%) value; 16 of 33 saline extracts produced a significant response (⩾10% reduction in bioluminescence). Organic extracts of sediments previously extracted with saline were also always toxic in the Microtox® bioassay but were less toxic than sediments not previously extracted. Organic EC50 and SLC were inversely related to concentrations of sediment contaminants, principally low- and high-molecular-weight polycyclic aromatic hydrocarbons (PAHs). This relationship was strongest for the organic solvent extracts of sediments tested in the bioassay. Organic solvent extracts of sediments from Boston Harbor were also significantly more toxic in the Microtox® bioassay than those from the Hudson-Raritan estuary, even though sediment concentrations of PAHs, a measure of anthropogenic contamination, were similar. The cause for the differential toxicity is unknown at this time, but chemical contaminants other than chlorinated hydrocarbons (CHs) and PAHs may be contributing to the observed toxicity in the Microtox® bioassay using organic extracts of sediment. Testing sediment toxicity using organic extracts of sediment with the Microtox® bioassay provides better estimates of toxicity due to sediment contaminants than using saline extracts of sediments.

Neurological disease rises from ocean to bring model for human epilepsy to life.

Abstract: Domoic acid of macroalgal origin was used for traditional and medicinal purposes in Japan and largely forgotten until its rediscovery in diatoms that poisoned 107 people after consumption of contaminated mussels. The more severely poisoned victims had seizures and/or amnesia and four died; however, one survivor unexpectedly developed temporal lobe epilepsy (TLE) a year after the event. Nearly a decade later, several thousand sea lions have stranded on California beaches with neurological symptoms. Analysis of the animals stranded over an eight year period indicated five clusters of acute neurological poisoning; however, nearly a quarter have stranded individually outside these events with clinical signs of a chronic neurological syndrome similar to TLE. These poisonings are not limited to sea lions, which serve as readily observed sentinels for other marine animals that strand during domoic acid poisoning events, including several species of dolphin and whales. Acute domoic acid poisoning is five-times more prominent in adult female sea lions as a result of the proximity of their year-round breeding grounds to major domoic acid bloom events. The chronic neurological syndrome, on the other hand, is more prevalent in young animals, with many potentially poisoned in utero. The sea lion rookeries of the Channel Islands are at the crossroads of domoic acid producing harmful algal blooms and a huge industrial discharge site for dichlorodiphenyltrichloroethane (DDTs). Studies in experimental animals suggest that chronic poisoning observed in immature sea lions may result from a spatial and temporal coincidence of DDTs and domoic acid during early life stages. Emergence of an epilepsy syndrome from the ocean brings a human epilepsy model to life and provides unexpected insights into interaction with legacy contaminants and expression of disease at different life stages.