Abstract
To define nanoflagellate-bacteria interactions and potential trophic levels within the microbial food web in the oligotrophic South China Sea, we conducted fourteen size-fractionation experiments in which seawater was filtered through 1, 2, 5, 10, 20, 60, and 200 μm membranes or meshes and the growth of four groups of picoplankton, Prochlorococcus, Synechococcus, high DNA heterotrophic bacteria, and low DNA heterotrophic bacteria were monitored in each filtrate after 24 hours of incubation. Removing grazers by filtration would relieve the grazing pressure on lower trophic levels which finally influenced the net growth rates of picoplankton. The growth patterns of Prochlorococcus and Synechococcus were similar, with higher growth rates in the < 1 μm or < 2 μm treatments, a second peak in the < 10 μm treatments and often a third peak in the < 200 μm treatments. The net growth rates of low DNA heterotrophic bacteria were little influenced by size-fractionation. Due to a subgroup of high DNA heterotrophic bacteria with larger size and higher DNA content which appeared to resist the grazing by < 5 μm nanoflagellates, the net growth rates of high DNA heterotrophic bacteria were higher in the < 2 μm or < 5 μm treatments with a second peak in the < 60 μm treatments. A general pattern of five potential trophic levels (< 2 μm, 2-5 μm, 5-10 μm, 10-60 μm, 60-200 μm) was revealed combining all the experiments, confirming the existence of multiple trophic levels within the microbial food web in the oligotrophic South China Sea.
| Original language | English |
|---|---|
| Pages (from-to) | 59-66 |
| Number of pages | 8 |
| Journal | Journal of Experimental Marine Biology and Ecology |
| Volume | 368 |
| Issue number | 1 |
| Early online date | 17 Nov 2008 |
| DOIs | |
| Publication status | Published - 15 Jan 2009 |
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Keywords
- grazing
- microbial food web
- picoplankton
- size-fractionation
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Trophic interactions within the microbial food web in the South China Sea revealed by size-fractionation method. / Chen, Bingzhang; Liu, Hongbin; Wang, Zongling.
In: Journal of Experimental Marine Biology and Ecology, Vol. 368, No. 1, 15.01.2009, p. 59-66.Research output: Contribution to journal › Article
TY - JOUR
T1 - Trophic interactions within the microbial food web in the South China Sea revealed by size-fractionation method
AU - Chen, Bingzhang
AU - Liu, Hongbin
AU - Wang, Zongling
PY - 2009/1/15
Y1 - 2009/1/15
N2 - To define nanoflagellate-bacteria interactions and potential trophic levels within the microbial food web in the oligotrophic South China Sea, we conducted fourteen size-fractionation experiments in which seawater was filtered through 1, 2, 5, 10, 20, 60, and 200 μm membranes or meshes and the growth of four groups of picoplankton, Prochlorococcus, Synechococcus, high DNA heterotrophic bacteria, and low DNA heterotrophic bacteria were monitored in each filtrate after 24 hours of incubation. Removing grazers by filtration would relieve the grazing pressure on lower trophic levels which finally influenced the net growth rates of picoplankton. The growth patterns of Prochlorococcus and Synechococcus were similar, with higher growth rates in the < 1 μm or < 2 μm treatments, a second peak in the < 10 μm treatments and often a third peak in the < 200 μm treatments. The net growth rates of low DNA heterotrophic bacteria were little influenced by size-fractionation. Due to a subgroup of high DNA heterotrophic bacteria with larger size and higher DNA content which appeared to resist the grazing by < 5 μm nanoflagellates, the net growth rates of high DNA heterotrophic bacteria were higher in the < 2 μm or < 5 μm treatments with a second peak in the < 60 μm treatments. A general pattern of five potential trophic levels (< 2 μm, 2-5 μm, 5-10 μm, 10-60 μm, 60-200 μm) was revealed combining all the experiments, confirming the existence of multiple trophic levels within the microbial food web in the oligotrophic South China Sea.
AB - To define nanoflagellate-bacteria interactions and potential trophic levels within the microbial food web in the oligotrophic South China Sea, we conducted fourteen size-fractionation experiments in which seawater was filtered through 1, 2, 5, 10, 20, 60, and 200 μm membranes or meshes and the growth of four groups of picoplankton, Prochlorococcus, Synechococcus, high DNA heterotrophic bacteria, and low DNA heterotrophic bacteria were monitored in each filtrate after 24 hours of incubation. Removing grazers by filtration would relieve the grazing pressure on lower trophic levels which finally influenced the net growth rates of picoplankton. The growth patterns of Prochlorococcus and Synechococcus were similar, with higher growth rates in the < 1 μm or < 2 μm treatments, a second peak in the < 10 μm treatments and often a third peak in the < 200 μm treatments. The net growth rates of low DNA heterotrophic bacteria were little influenced by size-fractionation. Due to a subgroup of high DNA heterotrophic bacteria with larger size and higher DNA content which appeared to resist the grazing by < 5 μm nanoflagellates, the net growth rates of high DNA heterotrophic bacteria were higher in the < 2 μm or < 5 μm treatments with a second peak in the < 60 μm treatments. A general pattern of five potential trophic levels (< 2 μm, 2-5 μm, 5-10 μm, 10-60 μm, 60-200 μm) was revealed combining all the experiments, confirming the existence of multiple trophic levels within the microbial food web in the oligotrophic South China Sea.
KW - grazing
KW - microbial food web
KW - picoplankton
KW - size-fractionation
UR - http://www.scopus.com/inward/record.url?scp=56949100399&partnerID=8YFLogxK
UR - https://www.sciencedirect.com/journal/journal-of-experimental-marine-biology-and-ecology
U2 - 10.1016/j.jembe.2008.10.012
DO - 10.1016/j.jembe.2008.10.012
M3 - Article
VL - 368
SP - 59
EP - 66
JO - Journal of Experimental Marine Biology and Ecology
JF - Journal of Experimental Marine Biology and Ecology
SN - 0022-0981
IS - 1
ER -