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| Titel |
The "neutral" community structure of planktonic herbivores, tintinnid ciliates of the microzooplankton, across the SE Tropical Pacific Ocean |
| VerfasserIn |
J. R. Dolan, M. E. Ritchie, J. Ras |
| 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 ; 4, no. 3 ; Nr. 4, no. 3 (2007-06-07), S.297-310 |
| Datensatznummer |
250001727
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| Publikation (Nr.) |
 copernicus.org/bg-4-297-2007.pdf |
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| Zusammenfassung |
| We assessed the community characteristics of a group of planktonic
herbivores across a species-rich area, the SE Pacific Ocean. A series of 22
stations between the Marquise Islands (7° S 142° W) and the coast of
Chile (35° S 73° W) was sampled during the BIOSOPE cruise in 2004. We
examined the relationships between taxonomic diversity, morphological
diversity, patterns of tintinnid species assemblage, and phytoplankton
abundance. Tintinnid community characteristics were estimated from large
volume (20–60 l) discrete depth sampling and phytoplankton were
characterized based on HPLC pigment signatures. Across the transect, average
water column concentrations of tintinnids ranged from 2–40 cells l−1 or
8–40 ng C l−1, and were positively related to chlorophyll a
concentrations which varied between 0.07–2 µg l−1. Large
numbers of tintinnid taxa were found, 18–41 species per station, yielding
a total of 149 species. Among stations, morphological and taxonomic
diversity metrics co-varied but were not significantly related to
phytoplankton diversity estimated using a pigment-based size-diversity
metric. Taxonomic diversity of tintinnids, as H' or Fishers' alpha, was
inversely related to chlorophyll concentration and positively to the depth
of the chlorophyll maximum layer. Species abundance distributions were
compared to geometric, log-series and log-normal distributions. For most
stations, the observed distribution most closely matched log-series,
coherent with the neutral theory of random colonization from a large species
pool. Occurrence rates of species were correlated with average abundance
rather than specific characteristics of biomass or lorica oral diameter
(mouth) size. Among stations, species richness was correlated with both the
variety of mouth sizes (lorica oral diameters) as well as numbers of species
per mouth size, also consistent with random colonization. |
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