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.

Biochemistry: a cadmium enzyme from a marine diatom.

Abstract: The ocean biota contains a vast reservoir of genomic diversity. Here we present the sequence and preliminary characterization of a protein that is a cadmium-containing carbonic anhydrase from the marine diatom Thalassiosira weissflogii. The existence of a cadmium enzyme in marine phytoplankton may indicate that there is a unique selection pressure for metalloenzymes in the marine environment, and our discovery provides a long-awaited explanation for the nutrient-like behaviour of cadmium in the oceans.

Projected 21st century decrease in marine productivity: a multi-model analysis

Abstract: Changes in marine net primary productivity (PP) and export of particulate organic carbon (EP) are projected over the 21st century with four global coupled carbon cycle-climate models. These include representations of marine ecosystems and the carbon cycle of different structure and complexity. All four models show a decrease in global mean PP and EP between 2 and 20% by 2100 relative to preindustrial conditions, for the SRES A2 emission scenario. Two different regimes for productivity changes are consistently identified in all models. The first chain of mechanisms is dominant in the low- and mid-latitude ocean and in the North Atlantic: reduced input of macro-nutrients into the euphotic zone related to enhanced stratification, reduced mixed layer depth, and slowed circulation causes a decrease in macro-nutrient concentrations and in PP and EP. The second regime is projected for parts of the Southern Ocean: an alleviation of light and/or temperature limitation leads to an increase in PP and EP as productivity is fueled by a sustained nutrient input. A region of disagreement among the models is the Arctic, where three models project an increase in PP while one model projects a decrease. Projected changes in seasonal and interannual variability are modest in most regions. Regional model skill metrics are proposed to generate multi-model mean fields that show an improved skill in representing observation-based estimates compared to a simple multi-model average. Model results are compared to recent productivity projections with three different algorithms, usually applied to infer net primary production from satellite observations.

Regulation of gross growth efficiency and ammonium regeneration in bacteria by substrate C: N ratio1

Abstract: Natural assemblages of marine bacteria were cultured on combinations of C and N sources (amino acids, glucose, and NH,‘) to span a range of substrate C: N ratios from 1.5 : 1 to 10 : 1. Catabolic metabolism of the N component of amino acid substrates led to NH,+ regeneration during exponential growth. The efficiency of this regeneration (RN) and also of the carbon gross growth efficiency (GGE) generally was independent of the sources of C and N, but increased as the C : N ratio of the substrate (C : NJ decrcascd relative to the C : N ratio of the bacterial biomass (C : NJ. The clemental chemical composition (C : N: P ratio) of the bacterial biomass was relatively invariant at about 45 : 9 : 1 and the gross growth efficiency varied from a threshold value of about 40-50% at C : Ns > 6 : 1 up to 94% when C : N, was 1.5 : 1. Hence, R, varied from 00/o when C : N, was 10: 1 up to 86% when C: N, was 1.5 : 1. Inorganic sources of both N and P were taken up only in stoichiometric quantities during this phase of growth. Regeneration of NH,+ during the stationary phase as well as of POd3- occurred, most likely due to endogenous metabolism or cell death, but the magnitude of this regeneration seemed to increase greatly only when C: N, was ~6 : 1. Considering that amino acids frequently do not provide all of the N required and that carbohydrates often are the major C source for growth of marine bacteria, we speculate that C : Ns of available substrates in marine waters is > 10 : 1. Hence, actively growing bacteria may be inefficient remineralizers of N.

Otolith chemistry to describe movements and life-history parameters of fishes : hypotheses, assumptions, limitations and inferences

Abstract: in ever-increasing numbers, researchers wish to extract information based on chemi - cal analyses from otoliths to determine movements and life-history patterns of fish. such analyses make assumptions about chemical incorporation and interpretation that are beyond those that are important for stock discrimination studies, another common application. The authors aim to clarify the methods of determining fish movement based on natural and artificial otolith chemical tags and review current trends in determining movement using otolith chemistry, otolith sampling methods, and what influences otolith chemistry. both spatial and temporal variability in water and otolith chemistries, which underpin the assumptions of several methods, are discussed. Five methods for determining movement and migration of fish are outlined: (1) estimates of movement and life-history traits of a single fish group, (2) assessing connectivity among groups using natural chemical tags in otoliths, (3) transgenerational marks to determine parentage and natal origins, (4) profile analysis to define life-history variation within a population and (5) profile analysis to describe movements through different environments. Within each of these methods, background information, specific hypotheses being tested and assumptions and limitations of each technique are provided. Finally,