Influence of elevated river flow on hypoxia occurrence, nutrient concentration and microbial dynamics in a tropical estuary
We sampled the Klang estuary during the inter-monsoon and northeast monsoon period (July– Nov 2011, Oct–Nov 2012), which coincided with higher rainfall and elevated Klang River flow. The increased freshwater inflow into the estuary resulted in water column stratification that was observed durin...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Springer
2020
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/32344/1/Influence%20of%20elevated%20river%20flow%20on%20hypoxia%20occurrence%2C%20nutrient%20concentration%20-%20Copy.pdf http://ir.unimas.my/id/eprint/32344/ https://link.springer.com/article/10.1007/s10661-020-08625-3 |
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| Summary: | We sampled the Klang estuary during the
inter-monsoon and northeast monsoon period (July–
Nov 2011, Oct–Nov 2012), which coincided with
higher rainfall and elevated Klang River flow. The
increased freshwater inflow into the estuary resulted in
water column stratification that was observed during
both sampling periods. Dissolved oxygen (DO) dropped
below 63 μM, and hypoxia was observed. Elevated river
flow also transported dissolved inorganic nutrients,
chlorophyll a and bacteria to the estuary. However,
bacterial production did not correlate with DO concentration
in this study. As hypoxia was probably not due to
in situ heterotrophic processes, deoxygenated waters
were probably from upstream. We surmised this as
DO correlated with salinity (R2 = 0.664, df = 86,
p < 0.001). DO also decreased with increasing flushing
time (R2 = 0.556, df = 11, p < 0.01), suggesting that
when flushing time (> 6.7 h), hypoxia could occur at
the Klang estuary. Here, we presented a model that
related riverine flow rate to the post-heavy rainfall hypoxia that explicated the episodic hypoxia at Klang estuary. As Klang estuary supports aquaculture and cockle
culture, our results could help protect the aquaculture
and cockle culture industry here. |
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