Woods Hole Oceanographic Institution

About: Woods Hole Oceanographic Institution is a nonprofit organization based out in Falmouth, Massachusetts, United States. It is known for research contribution in the topics: Population & Mantle (geology). The organization has 5685 authors who have published 18396 publications receiving 1202050 citations. The organization is also known as: WHOI.

The contribution of microorganisms to particulate carbon and nitrogen in surface waters of the Sargasso Sea near Bermuda

Abstract: Seawater samples were collected from the euphotic zone of the Sargasso Sea near Bermuda in August of 1989 and March–April of 1990. Microbial population abundances, chlorophyll concentration, particulate carbon and particulate nitrogen were measured. Calculations were performed to establish the relative and absolute importance of the various microbial assemblages. The choice of conversion factors (g C and N cell −1 , or g C and N μm −3 ) for the microbial populations dramatically affected the estimation of “living” and “detrital” particulate material in the samples, and the relative importance of the various microbial groups. Averaged over all samples on either of the two cruises, microbial biomass constituted a greater proportion of the total particulate carbon and nitrogen during March–April (55% and 63%, respectively), than during August (≈24% and 30%, respectively) using “constrained” conversion factors that were derived. Accordingly, detrital material constituted the bulk of the particulate material during August, but was similar to the amount of microbial biomass during March–April. The bacterial assemblage constituted the largest single pool of microbial carbon (35%) and nitrogen (45%) in the water, and a significant fraction of the total particulate carbon (≈10–20%) and nitrogen (≈15–30%). Phototrophic nanoplankton (microalgae 2–20 μm in size) were second in overall biomass, and often dominated the microbial biomass in the deep chlorophyll maxima that were present during both cruises. The results temper recent assertions concerning the overwhelming importance of bacterial biomass in the oligotrophic Sargasso Sea but still support a major role for these microorganisms in the open ocean as repositories for carbon and nutrients.

Sperm whale behaviour indicates the use of echolocation click buzzes 'creaks' in prey capture

Abstract: During foraging dives, sperm whales (Physeter macrocephalus) produce long series of regular clicks at 0.5-2 s intervals interspersed with rapid-click buzzes called "creaks". Sound, depth and orientation recording Dtags were attached to 23 whales in the Ligurian Sea and Gulf of Mexico to test whether the behaviour of diving sperm whales supports the hypothesis that creaks are produced during prey capture. Sperm whales spent most of their bottom time within one or two depth bands, apparently feeding in vertically stratified prey layers. Creak rates were highest during the bottom phase: 99.8% of creaks were produced in the deepest 50% of dives, 57% in the deepest 15% of dives. Whales swam actively during the bottom phase, producing a mean of 12.5 depth inflections per dive. A mean of 32% of creaks produced during the bottom phase occurred within 10 s of an inflection (13x more than chance). Sperm whales actively altered their body orientation throughout the bottom phase with significantly increased rates of change during creaks, reflecting increased manoeuvring. Sperm whales increased their bottom foraging time when creak rates were higher. These results all strongly support the hypothesis that creaks are an echolocation signal adapted for foraging, analogous to terminal buzzes in taxonomically diverse echolocating species.

Transport of freshwater by the oceans

Abstract: The global distribution of freshwater transport in the ocean is presented, based on an integration point at Bering Strait, which connects the Pacific and Atlantic oceans via the Artic Ocean. Through Bering Strait, 0.8 × 106 m3 s−1 of relatively fresh, 32.5 psu, water flows from the Pacific into the Arctic Ocean. Baumgrtner and Reichel's tabulation of the act gain of freshwater by the ocean in 5° latitude intervals is then integrated from the reference location at Bering Strait to yield the meridional freshwater transport in each ocean. Freshwater transport in the Pacific is directed northward at nearly all latitudes. In the Atlantic, the freshwater transport is directed southward at all latitudes, with a small southward freshwater transport out of the Atlantic across 35°S. Salt transport, which must be considered jointly with the freshwater transport, is northward throughout the Pacific and southward throughout the Atlantic (in the same direction as the freshwater flux) and is equal to the sal...

Macrofaunal colonization of disturbed deep-sea environments and the structure of deep-sea benthic communities

Abstract: Trays of azoic sediment and organic additions were used to determine the responses of deep-sea species to disturbance at two sites and south of New England: Deep Ocean Station One (DOS 1) at 1800-m depth and Deep Ocen Station Two (DOS 2) at 3600-m depth. Species diversity was higher in the natural community at the deeper site. Rates of colonization were similar at the two sites, but slow relative to those in similar experiments conducted in shallow water. Trays of azoic sediment resting on the bottom for 5 years did not achieve the density of individuals or species found in the natural community. Species of polychaete worms in the families Spionidae, Capitellidae, and Sigalionidae were the most consistent colonists regardless of the kind of disturbance. Highest densities were achieved in patches of organic material. At the deeper DOS 2 site, densities of the sibling species of Capitella were 829 per m2 in the vicinity of wood blocks, and the dorvilleid polychaete, Ophryothrocha sp. A, occurred dat 1274 per m2 in natural, patchy accumulations of decomposing seaweed, Sargassum. The response to disturbance represented by the sediment trays was much more variable at DOS 2 than at DOS 1, with several taxa achieving high densities in only one tray. Pholoe anoculata, Ophelina cylindricaudata, and Hesionidae spp. were consistent colonists of the sediment trays at DOS 1. A few taxa such as Capitella spp., Myriotrochus spp. and Ophiura ljungmani increased greatly under screens. Predators excluded by the screens in these experiments may normally prevent juveniles of these species from becoming abundant. Occasional escape from predation may explain the rare instances of dense populations of these species. The responses of deep-sea populations to Sargassum, wood and azoic sediments indicate that a temporal mosaic of small-scale patches of organic enrichment and disturbance are very important in structuring deep-sea communities. The high diversity of species in the deep sea is maintained by: (1) patchiness of organic input against a background of low productivity; (2) sporadic, small-scale, discrete disturbance events occurring against a background of relative constancy; (3) the lack of barriers to dispersal among populations distributed over an enormous area.

Western Boundary Currents and Frontal Air–Sea Interaction: Gulf Stream and Kuroshio Extension

Abstract: In the Northern Hemisphere midlatitude western boundary current (WBC) systems there is a complex interaction between dynamics and thermodynamics and between atmosphere and ocean. Their potential contribution to the climate system motivated major parallel field programs in both the North Pacific [Kuroshio Extension System Study (KESS)] and the North Atlantic [Climate Variability and Predictability (CLIVAR) Mode Water Dynamics Experiment (CLIMODE)], and preliminary observations and analyses from these programs highlight that complexity. The Gulf Stream (GS) in the North Atlantic and the Kuroshio Extension (KE) in the North Pacific have broad similarities, as subtropical gyre WBCs, but they also have significant differences, which affect the regional air–sea exchange processes and their larger-scale interactions. The 15-yr satellite altimeter data record, which provides a rich source of information, is combined here with the longer historical record from in situ data to describe and compare the curr...