Nitrogen dynamics and phytoplankton community structure: the role of organic nutrients
Date
2017-06-15
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Publisher
Springer
Abstract
Dissolved organic nitrogen (DON) is
recognised as an important N source for phytoplankton. However, its relative importance for phytoplankton nutrition and community composition has not
been studied comprehensively. This study, conducted
in a typical Scottish fjord, representative of nearpristine coastal environments, evaluates the utilisation
of DON and dissolved inorganic nitrogen (DIN) by
different microbial size fractions and the relationship
of phytoplankton community composition with DON
and other parameters. The study demonstrated that
DON was important in supporting phytoplankton
throughout the yearly production cycle. The higherthan-expected urea uptake rates and large fraction of
the spring bloom production supported by DON
suggested that organic N not only contributes to
regenerated production and to the nutrition of the
small phytoplankton fraction, but can also contribute
substantially to new production of the larger phytoplankton in coastal waters. Multivariate statistical
techniques revealed two phytoplankton assemblages
with peaks in abundance at different times of the year:
a spring group dominated by Skeletonema spp.,
Thalassiosira spp., and Pseudo-nitzschia spp. group
delicatissima; and a summer/autumn group dominated
by Chaetoceros spp., Scrippsiella spp., and Pseudonitzschia spp. group seriata. The multivariate pattern
in community composition and abundance of these
taxa was significantly correlated with the multivariate
pattern of DON, urea, dissolved free amino acids,
DIN, temperature, salinity, and daylength, with daylength and urea being particularly important, suggesting both physical and chemical controls on community
composition.
Description
Publication history: Accepted - 7 June 2017; Published online - 15 June 2017.
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Article
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Keywords
Dissolved organic nitrogen, Phytoplankton, Nitrogen uptake, Community composition
Citation
Moschonas, G., Gowen, R. J., Paterson, R. F., Mitchell, E., Stewart, B. M., McNeill, S., Glibert, P. M. and Davidson, K. (2017) ‘Nitrogen dynamics and phytoplankton community structure: the role of organic nutrients’, Biogeochemistry, 134(1–2), pp. 125–145. doi: 10.1007/s10533-017-0351-8.