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Details van artikel 42 van 146 gevonden artikelen
| Titel: |
Effects of CO2 on particle size distribution and phytoplankton abundance during a mesocosm bloom experiment (PeECE II) |
| Auteur: |
A. Engel K. Schulz U. Riebesell R. Bellerby B. Delille M. Schartau |
| Verschenen in: |
Biogeosciences discussions |
| Paginering: | Jaargang 4 (2007) nr. 6 pagina's 4101-4133 |
| Jaar: |
2007 |
| Inhoud: |
The influence of seawater CO2 concentration on the size distribution of suspended particles (2–60 μm) and on phytoplankton abundance was investigated during a mesocosm experiment at the large scale facility (LFS) in Bergen, Norway, in the frame of the Pelagic Ecosystem CO2 Enrichment study (PeECE II). In nine outdoor enclosures the partial pressure of CO2 in seawater was modified by an aeration system to simulate past (~190 parts per million by volume (ppmV) CO2), present day (~370 ppmV CO2) and future (~700 ppmV CO2) CO2 conditions in triplicates. Due to initial addition of inorganic nutrients, phytoplankton blooms developed in all mesocosms and were monitored over a period of 19 days. Seawater samples were collected daily for analysing the abundance of suspended particles and phytoplankton with the Coulter Counter and Flow Cytometry, respectively. During the bloom period, the abundance of small particles (<4 μm) significantly increased at past, and decreased at future CO2 levels. At that time, the total surface to total volume ratio of suspended particles was significantly related to DIC concentration in all mesocosms. Significant changes with respect to the CO2 treatment were also observed in the phytoplankton community structure. While some populations such as diatoms seemed to be insensitive to the CO2 treatment, others like Micromonas spp. increased with CO2, or showed maximum abundance at present day CO2 (i.e. Emiliania huxleyi). The strongest response to CO2 was observed in the abundance of small autotrophic nano-plankton that strongly increased during the bloom in the past CO2 mesocosms. Together, changes in particle size distribution and phytoplankton community indicate a complex interplay between the ability of the cell to physiologically respond to changes in CO2 and size selection. Size of cells is of general importance for a variety of processes in seawater such as diffusion-limited uptake of substrates, resource allocation, preditor-prey interactions, and gravitational settling. The observed changes in particle size distribution are therefore discussed with respect to biogeochemical cycling and ecosystem functioning. |
| Uitgever: |
Copernicus Publications (provided by DOAJ) |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 42 van 146 gevonden artikelen
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