Effects of eutrophication on the planktonic food web dynamics of marine coastal ecosystems: The case study of two tropical inlets.
We studied the plankton dynamics of two semi-enclosed marine coastal inlets of the north of Jurong Island separated by a causeway (SW Singapore; May 2012-April 2013). The west side of the causeway (west station) has residence times of ca. one year and is markedly eutrophic. The east side (east station) has residence times of one month and presents lower nutrient concentrations throughout the year. The higher nutrient concentrations at the west station did not translate into significantly higher concentrations of chlorophyll a, with the exception of some peaks at the end of the South West Monsoon. Microzooplankton were more abundant at the west station. The west station exhibited more variable abundances of copepods during the year than did the east station, which showed a more stable pattern and higher diversity. Despite the higher nutrient concentrations at the west station (never limiting phytoplankton growth), the instantaneous phytoplankton growth rates there were generally lower than at the east station. The phytoplankton communities at the west station were top-down controlled, largely by microzooplankton grazing, whereas those of the east station alternated between top-down and bottom-up control, with mesozooplankton being the major grazers. Overall, the trophic transfer efficiency from nutrients to mesozooplankton in the eutrophic west station was less efficient than in the east station, but this was mostly because a poor use of inorganic nutrients by phytoplankton rather than an inefficient trophic transfer of carbon. Some hypotheses explaining this result are discussed.
DHI-NTU Research Centre and Education Hub, 1 CleanTech Loop, #03-05 CleanTech1, 637141, Singapore.
Claire
C
Schmoker
DHI-NTU Research Centre and Education Hub, 1 CleanTech Loop, #03-05 CleanTech1, 637141, Singapore.
Francesca
F
Russo
DHI-NTU Research Centre and Education Hub, 1 CleanTech Loop, #03-05 CleanTech1, 637141, Singapore.
Guillaume
G
Drillet
DHI-NTU Research Centre and Education Hub, 1 CleanTech Loop, #03-05 CleanTech1, 637141, Singapore.
Aurore
A
Trottet
DHI-NTU Research Centre and Education Hub, 1 CleanTech Loop, #03-05 CleanTech1, 637141, Singapore.
Mohamed-Sofiane
MS
Mahjoub
Department of Science Education, National Taipei University of Education, Taipei 106, Taiwan, ROC.
Shih-Hui
SH
Hsiao
DHI-NTU Research Centre and Education Hub, 1 CleanTech Loop, #03-05 CleanTech1, 637141, Singapore; DHI Water and Environment-Denmark, Agern Allé 5, 2970 Hørsholm, Denmark.
Ole
O
Larsen
National Parks Board, 1 Cluny Road, 259569, Singapore.
Karenne
K
Tun
Institut de Ciències del Mar, CSIC, Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain. Electronic address: acalbet@icm.csic.es.
Albert
A
Calbet
D000818:Animals; D059001:Aquatic Organisms / Q000502:physiology*; D061006:Bays; D002734:Chlorophyll; D000077194:Chlorophyll A; D033342:Copepoda; D017753:Ecosystem; D004784:Environmental Monitoring; D005068:Eutrophication; D020387:Food Chain; D010933:Plankton; D012621:Seasons; D012623:Seawater; D012846:Singapore
D002734:Chlorophyll; D000077194:Chlorophyll A
Eutrophication; Food web; Grazing; Growth; Monsoon; Phytoplankton; Singapore; Trophic efficiency; Zooplankton