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SEE PROFILE
, 2016
"... Comparison of different filter types on chlorophyll-a retention and nutrient measurements ..."
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Comparison of different filter types on chlorophyll-a retention and nutrient measurements
the Creative Commons Attribution 3.0 License. Ocean Science Optical tools for ocean monitoring and research
, 2009
"... Abstract. Requirements for understanding the relationships between ocean color and suspended and dissolved materials within the water column, and a rapidly emerging photonics and materials technology base for performing optical based analytical techniques have generated a diverse offering of commerc ..."
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Abstract. Requirements for understanding the relationships between ocean color and suspended and dissolved materials within the water column, and a rapidly emerging photonics and materials technology base for performing optical based analytical techniques have generated a diverse offering of commercial sensors and research prototypes that perform op-tical measurements in water. Through inversion, these tools are now being used to determine a diverse set of related bio-geochemical and physical parameters. Techniques engaged include measurement of the solar radiance distribution, ab-sorption, scattering, stimulated fluorescence, flow cytome-try, and various spectroscopy methods. Selective membranes and other techniques for material isolation further enhance specificity, leading to sensors for measurement of dissolved oxygen, methane, carbon dioxide, common nutrients and a variety of other parameters. Scientists are using these mea-surements to infer information related to an increasing set of parameters and wide range of applications over relevant scales in space and time. 1
The effect of marginal ice-edge dynamics on production and export in the Southern Ocean along 1701W
, 2002
"... We present a synthesis of the rates of gross, new, net and primary production along with particulate organic carbon (POC) flux at 100m from four cruises along 1701W in the Southern Ocean. Concurrent satellite pigment data, a primary productivity model, and a nitrate mass balance are used to extrapol ..."
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We present a synthesis of the rates of gross, new, net and primary production along with particulate organic carbon (POC) flux at 100m from four cruises along 1701W in the Southern Ocean. Concurrent satellite pigment data, a primary productivity model, and a nitrate mass balance are used to extrapolate daily production estimates in space and time to seasonal and annual rates. From this analysis, we gain a better understanding of the timing, magnitude and impact of the phytoplankton blooms in this region. One of the dominant features with respect to plankton biomass is the association of high chlorophyll levels with the retreat of the sea ice which begins in October just south of the Polar Front. Our primary production model and satellite pigment data suggest higher production and flux levels characterize the marginal ice zone than previous estimates. Elevated rates of new production in ice impacted regions are restricted to relatively short periods following retreat of the ice edge. Export is found to lag the onset of production by up to 1 month. The ratio of POC flux at 100m to primary production when averaged over the entire season is quite high, increasing from 15 % to 25 % in the Subantarctic zones to 35–40 % near the Polar Front and as high as 50–65 % in the southernmost stations, just north of the Ross Sea gyre. Comparisons of phytoplankton community structure and Fe stress indicators suggest that blooms at the Polar Front are initially dominated by large centric diatoms, but are replaced by smaller pennate diatom and non-diatom species as Fe levels decrease. Further south, where Fe levels are
Primary productivity and its regulation in the Pacific Sector of the Southern Ocean
, 2002
"... We measured primary productivity in the Pacific Sector of the Southern Ocean as part of the Joint Global Ocean Flux Study. We collected data along 170W from 54S to 72S on four cruises during the austral growing season of 1997–1998. The cruises crossed the Subantarctic Front, the Antarctic Polar Fron ..."
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We measured primary productivity in the Pacific Sector of the Southern Ocean as part of the Joint Global Ocean Flux Study. We collected data along 170W from 54S to 72S on four cruises during the austral growing season of 1997–1998. The cruises crossed the Subantarctic Front, the Antarctic Polar Front (APF), the Southern Antarctic Circumpolar Current (ACC) Front, and the Southern Boundary of the ACC. Primary productivity and chlorophyll a increased rapidly in spring, peaked in summer, and decreased rapidly in fall, following the seasonal pattern of irradiance. In early spring (October), primary productivity was 20mmol Cm2 d1 and increased to 54mmol Cm2 d1 within 3 weeks. During peak irradiance (December), productivity reached its maximum throughout the study area with values ranging from 33 to 93mmol Cm2 d1 depending on station location. By February, average productivity dropped to 2071mmol Cm2 d1, and individual station values reached a minimum of 13mmol Cm2 d1. In early spring, chlorophyll was less than 0.5mg Chlm3 throughout the study area. In late spring and early summer, chlorophyll values were between 0.15 and 1.5mg Chlm3 depending on station location. By late summer, chlorophyll decreased to less than 0.3mg Chlm3 across the study region. Highest absolute values of productivity and biomass occurred near the southward-propagating Si gradient (DSimax). A spatial gradient in photosynthetic performance correlated with DSimax: photosynthetic performance was elevated in low silicic acid waters (less than 10mM) to the
