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Herrmann, M, Najjar RG, Neeley AR, Vila-Costa M, Dacey JWH, DiTullio GR, Kieber DJ, Kiene RP, Matrai PA, Simo R, Vernet M.  2012.  Diagnostic modeling of dimethylsulfide production in coastal water west of the Antarctic Peninsula. Continental Shelf Research. 32:96-109.   10.1016/j.csr.2011.10.017   AbstractWebsite

The rate of gross biological dimethylsulfide (DMS) production at two coastal sites west of the Antarctic Peninsula, off Anvers Island, near Palmer Station, was estimated using a diagnostic approach that combined field measurements from 1 January 2006 through 1 March 2006 and a one-dimensional physical model of ocean mixing. The average DMS production rate in the upper water column (0-60 m) was estimated to be 3.1 +/- 0.6 nM d(-1) at station B (closer to shore) and 2.7 +/- 0.6 nM d(-1) at station E (further from shore). The estimated DMS replacement time was on the order of 1 d at both stations. DMS production was greater in the mixed layer than it was below the mixed layer. The average DMS production normalized to chlorophyll was 0.5 +/- 0.1 (nM d(-1))/(mg m(-3)) at station B and 0.7 +/- 0.2 (nM d(-1))/(mg m(-3)) at station E. When the diagnosed production rates were normalized to the observed concentrations of total dimethylsulfoniopropionate (DMSPt, the biogenic precursor of DMS), we found a remarkable similarity between our estimates at stations B and E (0.06 +/- 0.02 and 0.04 +/- 0.01 (nM DMS d(-1))/(nM DMSP), respectively) and the results obtained in a previous study from a contrasting biogeochemical environment in the North Atlantic subtropical gyre (0.047 +/- 0.006 and 0.087 +/- 0.014 (nM DMS d(-1))/(nM DMSP) in a cyclonic and anticyclonic eddy, respectively). We propose that gross biological DMS production normalized to DMSPt might be relatively independent of the biogeochemical environment, and place our average estimate at 0.06 +/- 0.01 (nM DMS d(-1))/(nM DMSPt). The significance of this finding is that it can provide a means to use DMSPt measurements to extrapolate gross biological DMS production, which is extremely difficult to measure experimentally under realistic in situ conditions. (C) 2011 Elsevier Ltd. All rights reserved.

Welschmeyer, NA, Copping AE, Vernet M, Lorenzen CJ.  1984.  Diel Fluctuation in Zooplankton Grazing Rate as Determined from the Downward Vertical Flux of Pheopigments. Marine Biology. 83:263-270.   10.1007/bf00397458   AbstractWebsite

The diel grazing activity of zooplankton was measured at a single study site in a temperate fjord, Dabob Bay, Washington, USA at several periods during spring, summer and fall of 1979–1981. Pheopigments were used as an indicator of herbivorous zooplankton activity. The downward vertical flux of pheopigment-containing fecal pellets was measured with sediment traps deployed over repetitive 4 h periods. Experiments were run for 24 to 36 h. A maximum in the flux of pheopigments was consistently noted within the euphotic zone during hours of darkness. Diel fluctuations in pheopigment flux showed amplitudes up to 29-fold. Nightly grazing activity accounted for 41 to 82% of the daily (24 h) grazing and was indirectly related to seasonal changes in daylength.

Cefarelli, AO, Ferrario ME, Almandoz GO, Atencio AG, Akselman R, Vernet M.  2010.  Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance. Polar Biology. 33:1463-1484.   10.1007/s00300-010-0794-z   AbstractWebsite

Fragilariopsis species composition and abundance from the Argentine Sea and Antarctic waters were analyzed using light and electron microscopy. Twelve species (F. curta, F. cylindrus, F. kerguelensis, F. nana, F. obliquecostata, F. peragallii, F. pseudonana, F. rhombica, F. ritscheri, F. separanda, F. sublinearis and F. vanheurckii) are described and compared with samples from the Frenguelli Collection, Museo de La Plata, Argentina. F. peragallii was examined for the first time using electron microscopy, and F. pseudonana was recorded for the first time in Argentinean shelf waters. New information on the girdle view is included, except for the species F. curta, F. cylindrus and F. nana, for which information already existed. In the Argentine Sea, F. pseudonana was the most abundant Fragilariopsis species, and in Antarctic waters, F. curta was most abundant. Of the twelve species of Fragilariopsis documented, four occurred in the Argentine Sea, nine in the Drake Passage and twelve in the Weddell Sea. F. curta, F. kerguelensis, F. pseudonana and F. rhombica were present everywhere.

Matrai, PA, Vernet M.  1997.  Dynamics of the vernal bloom in the marginal ice zone of the Barents Sea: Dimethyl sulfide and dimethylsulfoniopropionate budgets. Journal of Geophysical Research-Oceans. 102:22965-22979.   10.1029/96jc03870   AbstractWebsite

Phytoplankton is known to be a I;ey element in the production and eventual oceanic efflux of dimethyl sulfide (DMS) to the atmosphere. We hypothesized that the alternation of Phaeocystis pouchetii and diatoms, the two major algal components of the spring bloom, would modulate the input of particulate organic sulfur (POS), dimethylsulfoniopropionate (DMSP), and DMS into the mixed layer of the marginal ice zone. A bloom of diatoms is expected to present similar pathways but to have very different rates of POS/DMSP/DMS production and POS/DMSP sinking and no or low DMS flux to the atmosphere as contrasted to the cycling occurring during the P. pouchetii phase of the bloom. Our initial hypothesis cannot be accepted based on our observations in the Barents Sea during the spring of 1993. The contribution of diatoms to the water column budgets of DMSP and DMS was significant and cannot be overlooked. We suggest that the physiological stage of the bloom is perhaps more important to biogeochemical cycling than its phytoplankton species composition in controlling DMSP and DMS fluxes in Arctic waters. Loss of particulate DMSP in the mixed layer was mainly by release into the dissolved pool and by sedimentation rather than by grazing, except in ice-free waters. Cycling of DMS in the mixed layer was predominantly biological in ice-free waters, while in Polar Front waters, ventilation was proportionally more important due to depressed microbiology.