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.

Excretion of some organic compounds by marine phytoplankton1

Abstract: The excretion of photoassimilated carbon was determined for 22 species of unicellular marine algae in culture during periods of log-phase growth and for some natural marine phytoplankton populations from Vineyard Sound and the Gulf of Maine. Carbon 14 tracers gave some information about the composition of the excreted material. Most of the algae excreted 3-6s of their photoassimilated carbon during logarithmic growth. A few species excreted as much as 10-25s under the same conditions. Algae subjected to two different light intensities, 3,000 lux and 25,000 Iux, varied less than 30% in their relative rates of excretion. However, algae exposed to direct sunlight (lOO,OOO120,000 lux) had very high excretion rates, possibly resulting from damage to the cells by photooxidation. Glycolic acid formed 938% of the total carbon excretion in Olisthodiscus sp., Chaetoceros pelagicus, Chlorococcum sp. and Skeletonema costatum. Lower relative amounts were excreted by most of the species studied. Skeletonema costatum excreted considerably more glycolic acid at light intensities below 15,000 lux than above. This is contrary to the findings of other investigators using the freshwater alga Chlorella pyrenoidosa. The amount of carbon excreted as protein ranged from 0.2 to 5.9%, and that excreted as chloroform-soluble material ranged from 2.8 to 10.3% of the total. After electrodialysis, 12-340/O of the compounds were recovered in the anion fraction. Considerable quantities of amino acids and peptides were also detected as excretory products of many of the algae. A few species excreted a single substance almost exclusively. Thus, Chlorella sp. excreted mainly proline, Dunaliellu tertiolectu mainly glycerol, and Olisthodiscus sp. mainly mannitol. Apparently healthy populations of natural phytoplankton excreted 4-16s of their photoassimilated carbon. However, 17-38s was excreted by a sample taken at the end of a diatom bloom, when a large number of empty frustules was present.

FOZO, HIMU, and the rest of the mantle zoo

Abstract: Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 6 (2005): Q05007, doi:10.1029/2004GC000824.

Seasonal and Annual Fluxes of Nutrients and Organic Matter from Large Rivers to the Arctic Ocean and Surrounding Seas

Abstract: River inputs of nutrients and organic matter impact the biogeochemistry of arctic estuaries and the Arctic Ocean as a whole, yet there is considerable uncertainty about the magnitude of fluvial fluxes at the pan-Arctic scale. Samples from the six largest arctic rivers, with a combined watershed area of 11.3 × 106 km2, have revealed strong seasonal variations in constituent concentrations and fluxes within rivers as well as large differences among the rivers. Specifically, we investigate fluxes of dissolved organic carbon, dissolved organic nitrogen, total dissolved phosphorus, dissolved inorganic nitrogen, nitrate, and silica. This is the first time that seasonal and annual constituent fluxes have been determined using consistent sampling and analytical methods at the pan-Arctic scale and consequently provide the best available estimates for constituent flux from land to the Arctic Ocean and surrounding seas. Given the large inputs of river water to the relatively small Arctic Ocean and the dramatic impacts that climate change is having in the Arctic, it is particularly urgent that we establish the contemporary river fluxes so that we will be able to detect future changes and evaluate the impact of the changes on the biogeochemistry of the receiving coastal and ocean systems.