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.

Sources and contribution of terrigenous organic carbon to surface sediments in the Gulf of Mexico

Abstract: The sources and burial processes of organic matter in marine sediments are not well understood, yet they are important if we are to have a better understanding of the global carbon cycle1. In particular, the nature and fraction of the terrestrial organic carbon preserved in marine sediments is poorly constrained. Here we use the chemical and stable carbon isotope signatures of oxidation products from a macromolecular component (lignin)2 of the terrigenous organic matter preserved in offshore surface sediments in the Gulf of Mexico to complement similar data from an existing onshore transect3 in this region. The complete onshore–offshore data set, along with radiocarbon dates of the bulk organic material at the same sites, allows the differentiation of material originating from plants that photosynthesize using the C4 mechanism from those that undergo C3 photosynthesis. We conclude that the offshore lignins derive from erosion of the extensive grassland (C4) soils of the Mississippi River drainage basin, and that the nearshore lignins originate largely from C3 plant detritus from coastal forests and swamps. This distribution is probably due to the hydrodynamic sorting of the different source materials4 during their seaward transport. These results suggest that previous studies3,5 have significantly underestimated the terrigenous fraction of organic matter in offshore sediments by not recognizing the contribution of C4 vegetation to the carbon-isotope composition. Such an underestimate may force revisions in the assessment of past marine primary productivity and associated organic carbon fluxes6, and of organic matter preservation/remineralization7 and nutrient cycling8 in marine sediments.

THE PIRATA PROGRAM History, Accomplishments, and Future Directions *

Abstract: The Pilot Research Moored Array in the tropical Atlantic (PIRATA) was developed as a multinational observation network to improve our knowledge and understanding of ocean-atmosphere variability in the tropical Atlantic. PIRATA was motivated by fundamental scientific issues and by societal needs for improved prediction of climate variability and its impact on the economies of West Africa, northeastern Brazil, the West Indies, and the United States. In this paper the implementation of this network is described, noteworthy accomplishments are highlighted, and the future of PIRATA in the framework of a sustainable tropical Atlantic observing system is discussed. We demonstrate that PIRATA has advanced beyond a "Pilot" program and, as such, we have redefined the PIRATA acronym to be "Prediction and Research Moored Array in the Tropical Atlantic".

New chronology for the late Paleocene thermal maximum and its environmental implications

Abstract: The late Paleocene thermal maximum (LPTM) is associated with a brief, but intense, interval of global warming and a massive perturbation of the global carbon cycle. We have developed a new orbital chronology for Ocean Drilling Program (ODP) Site 690 (Weddell Sea, Southern Ocean) by using spectral analysis of high-resolution geochemical records. The LPTM interval spans 11 precessional cycles yielding a duration of 210 to 220 k.y. The δ 13 C anomaly associated with the LPTM has a magnitude of about −2.5‰ to −3‰; we show that about −2‰ of the excursion occurs within two steps that each were less than 1000 yr in duration. The remainder developed through a series of steps over ∼52 k.y. The timing of these steps is consistent with a series of nearly catastrophic releases of methane from gas hydrates, punctuated by intervals of relative equilibria between hydrate dissociation and carbon burial. Further, we are able to correlate the records between ODP Sites 690 and 1051 (western North Atlantic) on the scale of 21 k.y. cycles, which demonstrates that the details of the δ 13 C excursion are recognizable between distant sites. Comparison of cycle records at Sites 690 and 1051 suggests that sediment representing the interval ∼30 k.y. just prior to and at the onset of the LPTM are missing in the latter location. This unconformity probably resulted from slope failure accompanying methane hydrate dissociation within 10 k.y. of the start of the LPTM.

Pigments, size, and distributions of Synechococcus in the North Atlantic and Pacific Oceans

Abstract: Dual-beam flow cytometry was used to analyze the distribution and optical characteristics of Synechococcus in the North Atlantic and Pacific Oceans. The depth range over which Synechococcus cells were abundant was related to the depth of the nitrite maximum and the chlorophyll maximum, but was not significantly correlated with the depth of the surface isothermal layer. Dual-beam analysis of chromophore pigment types revealed that the majority of the populations were of the high-urobilin type; low-urobilin types, similar to the isolate WH7803, were found only in coastal waters where they almost always co-occurred with high-urobilin strains. Phycoerythrin fluorescence intensity per cell increased dramatically with depth in the lower euphotic zone at all stations; at some open-ocean stations, very deep cells were as much as 100 times brighter than those at the surface. The maximal fluorescence intensity per cell was about the same at the coastal and oceanic stations, and the depth of maximal fluorescence was closely related to the depth of the nitrite maximum. At most stations, fluorescence per cell was constant throughout the mixed layer, but at some open-ocean stations it decreased continuously to the surface. The latter pattern suggests that mixing rates in these areas are slow relative to the abilities of the cells to photoacclimate. A distinct diel pattern in forward-angle light scatter was observed in cells in the mixed layer over vast regions, which we hypothesize to be coupled to growth of the cells during daylight hours.