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Holm-Hansen, O, Kahru M, Hewes CD.  2005.  Deep chlorophyll a maxima (DCMs) in pelagic Antarctic waters. II. Relation to bathymetric features and dissolved iron concentrations. Marine Ecology-Progress Series. 297:71-81.   10.3354/meps297071   AbstractWebsite

A deep chlorophyll a maximum (DCM) at depths between 60 and 90 m in waters south of the Antarctic Polar Front (APF) occurs only in pelagic waters where the chlorophyll a concentrations in the upper mixed layer (UML) are very low (generally < 0.2 mg m(-3)). Dissolved Fe concentrations in these waters with DCMs are also very low (generally < 0.2 nM) and are probably a limiting factor for phytoplankton growth and biomass. DCMs occur in the upper portion of the temperature minimum layer (TML), which is the winter residue of the Antarctic Surface Water (AASW). The higher phytoplankton biomass at these depths is thought to result from higher Fe concentrations in the winter remnant of the AASW as compared to that found in the overlying UML. A survey of the literature indicates that DCMs are located predominately over the deep ocean basins where enrichment of surface waters with Fe from either coastal sediments or from upwelling processes would be minimal. DCMs are not found in coastal waters or in pelagic regions where complex bottom topography causes upwelling of deep water with sufficiently high Fe concentrations to enhance surface chlorophyll a concentrations. Such enrichment of surface waters overlying or downstream of topographical seamounts or ridges that rise to within a few thousand meters of the surface usually results in elevated phytoplankton biomass in the UML and no DCM due to decreased solar irradiance in the TML. The effect of such enrichment of Fe in surface pelagic waters that results from upwelling processes is most pronounced in the Scotia Sea, in the Polar Frontal region downstream of South Georgia, over the Southwest Indian Ridge, over the Kerguelen Plateau, and over the Pacific Antarctic and Southeast Indian Ridges.

Smith, KL, Ruhl HA, Kahru M, Huffard CL, Sherman AD.  2013.  Deep ocean communities impacted by changing climate over 24 y in the abyssal northeast Pacific Ocean. Proceedings of the National Academy of Sciences of the United States of America. 110:19838-19841.   10.1073/pnas.1315447110   AbstractWebsite

The deep ocean, covering a vast expanse of the globe, relies almost exclusively on a food supply originating from primary production in surface waters. With well-documented warming of oceanic surface waters and conflicting reports of increasing and decreasing primary production trends, questions persist about how such changes impact deep ocean communities. A 24-y time-series study of sinking particulate organic carbon (food) supply and its utilization by the benthic community was conducted in the abyssal northeast Pacific (similar to 4,000-m depth). Here we show that previous findings of food deficits are now punctuated by large episodic surpluses of particulate organic carbon reaching the sea floor, which meet utilization. Changing surface ocean conditions are translated to the deep ocean, where decadal peaks in supply, remineralization, and sequestration of organic carbon have broad implications for global carbon budget projections.

Mitchell, BG, Kahru M, Wieland JD, Stramska M.  2002.  Determination of spectral absorption coefficients of particles, dissolved material and phytoplankton for discrete water samples. Ocean optics protocols for satellite ocean color sensor validation, revision 3. 2( Mueller JL, Fargion GS, Eds.)., Greenbelt, Md.: National Aeronautics and Space Administration, Goddard Space Flight Center Abstract
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Mitchell, BG, Bricaud A, Carder K, Cleveland J, Ferri GM, Gould RJ, Kahru M, Kishino M, Maske H, Moisan T, Moore L, Nelson NB, Phinney D, Reynolds RA, Sosik HM, Stramski D, Tassan S, Trees C, Weidemann A, Wieland JD, Vodacek A.  2000.  Determination of spectrl absorption coefficients of particles, dissolved material and phytoplankton for discrete water samples. Ocean optics protocols for satellite ocean color sensor validation, Revision 2, NASA Technical Memorandum 2000-209966m/cgaoer 12 m o. ( Fargion GS, Mueller JL, McClain CR, Eds.).:125-153., Greenbelt, Md.: National Aeronautics and Space Administration, Goddard Space Flight Center Abstract

"This document stipulates protocols for measuring bio-optical and radiometric data for the Senor Inter comparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities and algorithm development. This document supersedes the earlier version published as Volume 25 in the SeaWiFS Technical report series ..."

Kahru, M, Hakansson B, Rud O.  1995.  Distributions of the Sea-Surface Temperature Fronts in the Baltic Sea as Derived from Satellite Imagery. Continental Shelf Research. 15:663-679.   10.1016/0278-4343(94)e0030-p   AbstractWebsite

A 9-month time series of satellite infrared imagery was used to examine the sea surface temperature (SST) variability in the northern and central Baltic Sea. Objective multi-level edge detection techniques were applied to find sharp SST gradient areas known as fronts. The spatial distribution of frontal frequency was calculated over time periods from a few days to 9 months covering different thermal and wind conditions. The 9-month average frequency that a front is detected in a pixel of 1.1 x 1.1 km is up to 10% in certain areas whereas the median is around 2%. Large scale fronts are aligned to the coast and isobaths, and occur predominantly in areas of straight and uniformly sloping bottom topography. The major frontal areas are along the eastern coast of the Bothnian Sea and along the north-western coast of the Gulf of Finland. Low large-scale frontal frequency is characteristic to areas with highly structured bottom topography. The major mechanism of front generation is coastal upwelling, being complemented by coastal jets, eddies, differential heating and cooling, and water exchange between basins with different water characteristics. Filaments (''squirts'') originating from upwelling areas are shown to be an important mechanism for transporting water and substances over long distances.