11 results match your criteria: "Massachusetts Institute of Technology and Woods Hole Oceanographic Institution[Affiliation]"

A global increase in offshore windfarm development is critical to our renewable energy future. Yet, widespread construction plans have generated substantial concern for impacts to co-occurring organisms and the communities they form. Pile driving construction, prominent in offshore windfarm development, produces among the highest amplitude sounds in the ocean creating widespread concern for a diverse array of taxa.

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Marine animals equipped with sensors provide vital information for understanding their ecophysiology and collect oceanographic data on climate change and for resource management. Existing methods for attaching sensors to marine animals mostly rely on invasive physical anchors, suction cups, and rigid glues. These methods can suffer from limitations, particularly for adhering to soft fragile marine species such as squid and jellyfish, including slow complex operations, unreliable fixation, tissue trauma, and behavior changes of the animals.

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Marine phytoplankton have a crucial role in the modulation of marine-based food webs, fishery yields and the global drawdown of atmospheric carbon dioxide. However, owing to sparse measurements before satellite monitoring in the twenty-first century, the long-term response of planktonic stocks to climate forcing is unknown. Here, using a continuous, multi-century record of subarctic Atlantic marine productivity, we show that a marked 10 ± 7% decline in net primary productivity has occurred across this highly productive ocean basin over the past two centuries.

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The original version of this Article contained errors in Fig. 6. In panel a, the grey highlights obscured the curves for CESM, CM2.

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Upwelling of global deep waters to the sea surface in the Southern Ocean closes the global overturning circulation and is fundamentally important for oceanic uptake of carbon and heat, nutrient resupply for sustaining oceanic biological production, and the melt rate of ice shelves. However, the exact pathways and role of topography in Southern Ocean upwelling remain largely unknown. Here we show detailed upwelling pathways in three dimensions, using hydrographic observations and particle tracking in high-resolution models.

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Reappraisal of hydrocarbon biomarkers in Archean rocks.

Proc Natl Acad Sci U S A

May 2015

Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139.

Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial. To resolve this debate, we performed a multilaboratory study of new cores from the Pilbara Craton, Australia, that were drilled and sampled using unprecedented hydrocarbon-clean protocols. Hopanes and steranes in rock extracts and hydropyrolysates from these new cores were typically at or below our femtogram detection limit, but when they were detectable, they had total hopane (<37.

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A comprehensive marine biomarker record of green and purple sulfur bacteria (GSB and PSB, respectively) is required to test whether anoxygenic photosynthesis represented a greater fraction of marine primary productivity during the Precambrian than the Phanerozoic, as current models of ocean redox evolution suggest. For this purpose, we analyzed marine rock extracts and oils from the Proterozoic to the Paleogene for C40 diagenetic products of carotenoid pigments using new analytical methods. Gas chromatography coupled with tandem mass spectrometry provides a new perspective on the temporal distributions of carotenoid biomarkers for phototrophic sulfur bacteria, specifically okenane, chlorobactane, and paleorenieratane.

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Transition from geostrophic turbulence to inertia-gravity waves in the atmospheric energy spectrum.

Proc Natl Acad Sci U S A

December 2014

Courant Institute of Mathematical Sciences, New York University, New York, NY 10012.

Midlatitude fluctuations of the atmospheric winds on scales of thousands of kilometers, the most energetic of such fluctuations, are strongly constrained by the Earth's rotation and the atmosphere's stratification. As a result of these constraints, the flow is quasi-2D and energy is trapped at large scales—nonlinear turbulent interactions transfer energy to larger scales, but not to smaller scales. Aircraft observations of wind and temperature near the tropopause indicate that fluctuations at horizontal scales smaller than about 500 km are more energetic than expected from these quasi-2D dynamics.

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Proteomic responses of oceanic Synechococcus WH8102 to phosphate and zinc scarcity and cadmium additions.

Front Microbiol

January 2014

Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution Woods Hole, MA, USA.

Synechococcus sp. WH 8102 is a motile marine cyanobacterium isolated originally from the Sargasso Sea. To test the response of this organism to cadmium (Cd), generally considered a toxin, cultures were grown in a matrix of high and low zinc (Zn) and phosphate (PO4 (3-)) and were then exposed to an addition of 4.

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Cyanobacteria are key players in the global carbon and nitrogen cycles and are thought to have been responsible for the initial rise of atmospheric oxygen during the Neoarchean. There is evidence that a class of membrane lipids known as hopanoids serve as biomarkers for bacteria, including many cyanobacteria, in the environment and in the geologic record. However, the taxonomic distributions and physiological roles of hopanoids in marine cyanobacteria remain unclear.

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1. Analysis of stable carbon isotopes is a valuable tool for studies of diet, habitat use and migration. However, significant variability in the degree of trophic fractionation (Delta(13)C(C-D)) between consumer (C) and diet (D) has highlighted our lack of understanding of the biochemical and physiological underpinnings of stable isotope ratios in tissues.

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