ISSN:
1432-2056
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary This study of nitrogen metabolism of phytoplankton was one component of a large multidisciplinary program designed to examine the biological productivity of the eastern Scotia Sea, Antarctica, with regard to the importance of the zone of mixing of the northern outflow of the Weddell Sea with Drake Passage waters. The total integrated N-uptake for the euphotic zone in the southwest part of the Scotia Sea was estimated to be in the range of 9.7–14.1 mmol N·m-2·d-1, while for the eastern part of the Scotia Sea it was less than half of this, being 2.1 to 4.7 mmol N·m-2·d-1. The rate of primary production could not be correlated with the front between the two major water masses. Assimilation rates of 15N-enriched substrates indicate that phytoplankton production in the Scotia Sea during austral summer subsists predominantly on ammonia (85%), with lower incorporation rates for nitrate (14%) and nitrite (1%). Nitrate assimilation was much more light-dependent than the uptake of ammonia. These data indicate that there is a rapid and extensive mineralization of organic matter in the surface waters, resulting in a recycling of nitrogen approximately eight times before it is lost from the euphotic zone. This has important implications with regard to the dynamics of the microbial food web in antarctic waters.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00448963
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