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General Session 2: Marine & estuarine biogeochemistry |
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Biogeochemistry of coastal water in the west and east coast of Peninsular Malaysia
GS2-16-S
Lim Joon Hai* , Institute of Ocean and Earth Sciences, Institute of Graduate Studies, University of Malaya
Lee Choon Weng, Laboratory of Microbial Ecology, Institute of Biological Sciences, University of Malaya
Bong Chui Wei, Laboratory of Microbial Ecology, Institute of Biological Sciences, University of Malaya
Presenter Email: joonhai_86@yahoo.com
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| In this study, we investigated biogeochemistry of the bed of water located from the shoreline at the west (≈ 5°47’ N, 100°10’ E) and east coast (≈ 2°50’ N, 103°37’ E) of Peninsular Malaysia. A linear transect that consists of five points was established at both west and east coast of Peninsular Malaysia (i.e. 5, 10, 15, 20 and 25 km). The west coast station was located at the northern Straits of Malacca while the east coast station was located on the southeast coast of Peninsular Malaysia, facing the South China Sea. For two years (2015 and 2016), we carried out sampling from March until May and July until September at the west and east coast station, respectively. The sampling period was during the southwest monsoon (March to October) where the wind and ocean currents are relatively weaker as opposed to that of northeast monsoon (November to February). Seawater temperatures (30.1 ± 0.9 °C) and salinity (31.7 ± 2.0 ppt) observed are relatively high and stable throughout the sampling period, typical of tropical waters. On average, ammonium (NH4), phosphate (PO4) and silicate (SiO4) concentrations were significantly higher at the west coast transect (NH4, 1.89 ± 1.41 μM; PO4, 0.28 ± 0.22 μM; SiO4, 0.65 ± 0.41 μM) than the east coast transect (NH4, 1.55 ± 1.07 μM; PO4, 0.14 ± 0.11 μM; SiO4, 0.51 ± 0.36 μM) (NH4, t= 2.34, df= 204, p< 0.05; PO4, t= 6.72, df= 183, p< 0.001; SiO4, t= 2.10, df= 183, p< 0.05). In contrast, NO2 + NO3 is not different between both transects and ranged from 0.10 to 5.63 μM. Chlorophyll a concentration was measured as a proxy for phytoplankton biomass and ranged from 0.06 to 8.23 μgL–1 and 0.24 to 3.48 μgL–1 at the west and the east coast transect, respectively. Through correlation analysis, east coast transect increased with phosphate concentration although the correlation index was relatively low (east coast: R2= 0.079, df= 123, p< 0.01). In contrast, chlorophyll a concentration at the west coast transect was independent of any of the inorganic nutrients measured. Other biological processes are currently being measured and analysed. |
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