Spring bloom onset in the Nordic Seas
The North Atlantic spring bloom is a massive annual growth event of marine phytoplankton, tiny free-floating algae that form the base of the ocean's food web and generates a large fraction of the global primary production of organic matter. The conditions that trigger the onset of the spring bl...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-06-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/3485/2016/bg-13-3485-2016.pdf |
| Summary: | The North Atlantic spring bloom is a massive annual growth event of marine
phytoplankton, tiny free-floating algae that form the base of the ocean's
food web and generates a large fraction of the global primary production of
organic matter. The conditions that trigger the onset of the spring bloom in
the Nordic Seas, at the northern edge of the North Atlantic, are studied
using in situ data from six bio-optical floats released
north of the Arctic Circle. It is
often assumed that spring blooms start as soon as phytoplankton cells daily
irradiance is sufficiently abundant that division rates exceed losses. The
bio-optical float data instead suggest the tantalizing hypothesis that Nordic
Seas blooms start when the photoperiod, the number of daily light hours
experienced by phytoplankton, exceeds a critical value, independently of
division rates. The photoperiod trigger may have developed at high latitudes
where photosynthesis is impossible during polar nights and phytoplankton
enters into a dormant stage in winter. While the first accumulation of
biomass recorded by the bio-optical floats is consistent with the photoperiod
hypothesis, it is possible that some biomass accumulation started before the
critical photoperiod but at levels too low to be detected by the
fluorometers. More precise observations are needed to test the photoperiod
hypothesis. |
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| ISSN: | 1726-4170 1726-4189 |