ORCID Profile
0000-0002-4968-1156
Current Organisation
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
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Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-02-2013
Abstract: In the Arctic, under-ice primary production is limited to summer months and is restricted not only by ice thickness and snow cover but also by the stratification of the water column, which constrains nutrient supply for algal growth. Research Vessel Polarstern visited the ice-covered eastern-central basins between 82° to 89°N and 30° to 130°E in summer 2012, when Arctic sea ice declined to a record minimum. During this cruise, we observed a widespread deposition of ice algal biomass of on average 9 grams of carbon per square meter to the deep-sea floor of the central Arctic basins. Data from this cruise will contribute to assessing the effect of current climate change on Arctic productivity, bio ersity, and ecological function.
Publisher: Copernicus GmbH
Date: 06-11-2018
Abstract: Abstract. Diatoms are generally the dominant contributors to the Arctic Ocean spring bloom, which is a key event in regional food webs in terms of capacity for secondary production and organic matter export. Dissolved silicic acid is an obligate nutrient for diatoms and has been declining in the European Arctic since the early 1990s. The lack of regional silicon cycling information precludes understanding the consequences of such changes for diatom productivity during the Arctic spring bloom. This study communicates the results from a cruise in the European Arctic around Svalbard, which reports the first concurrent data on biogenic silica production and export, export of diatom cells, the degree of kinetic limitation by ambient silicic acid, and diatom contribution to primary production. Regional biogenic silica production rates were significantly lower than those achievable in the Southern Ocean and silicic acid concentration limited the biogenic silica production rate in 95 % of s les. Compared to diatoms in the Atlantic subtropical gyre, regional diatoms are less adapted for silicic acid uptake at low concentration, and at some stations during the present study, silicon kinetic limitation may have been intense enough to limit diatom growth. Thus, silicic acid can play a critical role in diatom spring bloom dynamics. The diatom contribution to primary production was variable, ranging from % to ∼100 % depending on the bloom stage and phytoplankton composition. While there was agreement with previous studies regarding the export rate of diatom cells, we observed significantly elevated biogenic silica export. Such a discrepancy can be resolved if a higher fraction of the diatom material exported during our study was modified by zooplankton grazers. This study provides the most direct evidence to date suggesting the important coupling of the silicon and carbon cycles during the spring bloom in the European Arctic.
Publisher: Frontiers Media SA
Date: 12-03-2018
Publisher: American Geophysical Union (AGU)
Date: 07-2016
DOI: 10.1002/2016JC011816
Publisher: American Geophysical Union (AGU)
Date: 09-2015
DOI: 10.1002/2015JC011018
Location: No location found
Location: No location found
Location: Germany
Location: Germany
No related grants have been discovered for Mar Fernández-Méndez.