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.

Seasonal change in the flux of organic carbon to the deep Sargasso Sea

Abstract: Recent evidence1–5 has suggested that diurnal and annual periodicities affect the deep sea which traditionally had been thought to be the least variable environment at the surface of the Earth6,7. We report here what we believe to be the first direct measurements of seasonal change in the total flux of particles <13 cm and in the flux of organic carbon associated with those particles. The change seems to be related to seasonal change in the primary productivity of the surface water.

The role of the Beaufort Gyre in Arctic climate variability: Seasonal to decadal climate scales

Abstract: [1] This paper presents a new hypothesis along with supporting evidence that the Beaufort Gyre (BG) plays a significant role in regulating the arctic climate variability. We propose and demonstrate that the BG accumulates a significant amount of fresh water (FW) during one climate regime (anticyclonic) and releases this water to the North Atlantic (NA) during another climate regime (cyclonic). This hypothesis can explain the origin of the salinity anomaly (SA) periodically found in the NA as well as its role in the decadal variability in the Arctic region.

Steroids, triterpenoids and molecular oxygen

Abstract: There is a close connection between modern-day biosynthesis of particular triterpenoid biomarkers and presence of molecular oxygen in the environment. Thus, the detection of steroid and triterpenoi...

Lithotrophic iron-oxidizing bacteria produce organic stalks to control mineral growth: implications for biosignature formation

Abstract: Neutrophilic Fe-oxidizing bacteria (FeOB) are often identified by their distinctive morphologies, such as the extracellular twisted ribbon-like stalks formed by Gallionella ferruginea or Mariprofundus ferrooxydans. Similar filaments preserved in silica are often identified as FeOB fossils in rocks. Although it is assumed that twisted iron stalks are indicative of FeOB, the stalk's metabolic role has not been established. To this end, we studied the marine FeOB M. ferrooxydans by light, X-ray and electron microscopy. Using time-lapse light microscopy, we observed cells excreting stalks during growth (averaging 2.2 μm h−1). Scanning transmission X-ray microscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy show that stalks are Fe(III)-rich, whereas cells are low in Fe. Transmission electron microscopy reveals that stalks are composed of several fibrils, which contain few-nanometer-sized iron oxyhydroxide crystals. Lepidocrocite crystals that nucleated on the fibril surface are much larger (∼100 nm), suggesting that mineral growth within fibrils is retarded, relative to sites surrounding fibrils. C and N 1s NEXAFS spectroscopy and fluorescence probing show that stalks primarily contain carboxyl-rich polysaccharides. On the basis of these results, we suggest a physiological model for Fe oxidation in which cells excrete oxidized Fe bound to organic polymers. These organic molecules retard mineral growth, preventing cell encrustation. This model describes an essential role for stalk formation in FeOB growth. We suggest that stalk-like morphologies observed in modern and ancient samples may be correlated confidently with the Fe-oxidizing metabolism as a robust biosignature.