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| Titel |
Synoptic relationships between surface Chlorophyll-a and diagnostic pigments specific to phytoplankton functional types |
| VerfasserIn |
T. Hirata, N. J. Hardman-Mountford, R. J. W. Brewin, J. Aiken, R. Barlow, K. Suzuki, T. Isada, E. Howell, T. Hashioka, M. Noguchi-Aita, Y. Yamanaka |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 2 ; Nr. 8, no. 2 (2011-02-11), S.311-327 |
| Datensatznummer |
250005444
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| Publikation (Nr.) |
 copernicus.org/bg-8-311-2011.pdf |
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| Zusammenfassung |
| Error-quantified, synoptic-scale relationships between chlorophyll-a (Chl-a)
and phytoplankton pigment groups at the sea surface are presented. A total
of ten pigment groups were considered to represent three Phytoplankton Size
Classes (PSCs, micro-, nano- and picoplankton) and seven Phytoplankton
Functional Types (PFTs, i.e. diatoms, dinoflagellates, green algae,
prymnesiophytes (haptophytes), pico-eukaryotes, prokaryotes and
Prochlorococcus sp.). The observed relationships between Chl-a and PSCs/PFTs were well-defined
at the global scale to show that a community shift of phytoplankton at the
basin and global scales is reflected by a change in Chl-a of the total
community. Thus, Chl-a of the total community can be used as an index of not
only phytoplankton biomass but also of their community structure. Within
these relationships, we also found non-monotonic variations with Chl-a for
certain pico-sized phytoplankton (pico-eukaryotes, Prokaryotes and Prochlorococcus sp.) and nano-sized
phytoplankton (Green algae, prymnesiophytes). The relationships were
quantified with a least-square fitting approach in order to enable an
estimation of the PFTs from Chl-a where PFTs are expressed as a percentage of
the total Chl-a. The estimated uncertainty of the relationships depends on
both PFT and Chl-a concentration. Maximum uncertainty of 31.8% was found
for diatoms at Chl-a = 0.49 mg m−3. However, the mean uncertainty of the
relationships over all PFTs was 5.9% over the entire Chl-a range observed in situ
(0.02 < Chl-a < 4.26 mg m−3). The relationships were applied to SeaWiFS
satellite Chl-a data from 1998 to 2009 to show the global climatological
fields of the surface distribution of PFTs. Results show that microplankton
are present in the mid and high latitudes, constituting only ~10.9%
of the entire phytoplankton community in the mean field for 1998–2009, in
which diatoms explain ~7.5%. Nanoplankton are ubiquitous throughout
the global surface oceans, except the subtropical gyres, constituting ~45.5%, of which prymnesiophytes (haptophytes) are the major group explaining ~31.7% while green algae contribute ~13.9%. Picoplankton are
dominant in the subtropical gyres, but constitute ~43.6% globally,
of which prokaryotes are the major group explaining ~26.5%
(Prochlorococcus sp. explaining 22.8%), while pico-eukaryotes explain ~17.2%
and are relatively abundant in the South Pacific. These results may be of
use to evaluate global marine ecosystem models. |
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