 |
| Titel |
Multi-nutrient, multi-group model of present and future oceanic phytoplankton communities |
| VerfasserIn |
E. Litchman, C. A. Klausmeier, J. R. Miller, O. M. Schofield, P. G. Falkowski |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 3, no. 4 ; Nr. 3, no. 4 (2006-11-28), S.585-606 |
| Datensatznummer |
250001167
|
| Publikation (Nr.) |
 copernicus.org/bg-3-585-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| Phytoplankton community composition profoundly affects patterns of nutrient
cycling and the dynamics of marine food webs; therefore predicting present
and future phytoplankton community structure is crucial to understand how
ocean ecosystems respond to physical forcing and nutrient limitations. We
develop a mechanistic model of phytoplankton communities that includes
multiple taxonomic groups (diatoms, coccolithophores and prasinophytes),
nutrients (nitrate, ammonium, phosphate, silicate and iron), light, and a
generalist zooplankton grazer. Each taxonomic group was parameterized based
on an extensive literature survey. We test the model at two contrasting sites
in the modern ocean, the North Atlantic (North Atlantic Bloom Experiment,
NABE) and subarctic North Pacific (ocean station Papa, OSP). The model
successfully predicts general patterns of community composition and
succession at both sites: In the North Atlantic, the model predicts a spring
diatom bloom, followed by coccolithophore and prasinophyte blooms later in
the season. In the North Pacific, the model reproduces the low chlorophyll
community dominated by prasinophytes and coccolithophores, with low total
biomass variability and high nutrient concentrations throughout the year.
Sensitivity analysis revealed that the identity of the most sensitive
parameters and the range of acceptable parameters differed between the two
sites. We then use the model to predict community reorganization under
different global change scenarios: a later onset and extended duration of
stratification, with shallower mixed layer depths due to increased greenhouse
gas concentrations; increase in deep water nitrogen; decrease in deep water
phosphorus and increase or decrease in iron concentration. To estimate
uncertainty in our predictions, we used a Monte Carlo sampling of the
parameter space where future scenarios were run using parameter combinations
that produced acceptable modern day outcomes and the robustness of the
predictions was determined. Change in the onset and duration of
stratification altered the timing and the magnitude of the spring diatom
bloom in the North Atlantic and increased total phytoplankton and zooplankton
biomass in the North Pacific. Changes in nutrient concentrations in some
cases changed dominance patterns of major groups, as well as total
chlorophyll and zooplankton biomass. Based on these scenarios, our model
suggests that global environmental change will inevitably alter phytoplankton
community structure and potentially impact global biogeochemical cycles. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|