Laboratory of Microbial Ecology, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
Institute of Ocean and Earth Sciences, University of Malaya, 50603, Kuala Lumpur, Malaysia.
Environ Monit Assess. 2020 Sep 25;192(10):660. doi: 10.1007/s10661-020-08625-3.
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 (R = 0.664, df = 86, p < 0.001). DO also decreased with increasing flushing time (R = 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.
我们在季风间歇期和东北季风期（2011 年 7 月至 11 月、2012 年 10 月至 11 月）对巴生河口进行了采样，这期间降雨量较大，且巴生河流量较高。河口的淡水流入增加导致在两次采样期间都观察到水柱分层。溶解氧（DO）降至 63μM 以下，出现缺氧现象。较高的河流流量也将溶解无机养分、叶绿素 a 和细菌输送到河口。然而，在本研究中，细菌生产力与 DO 浓度没有相关性。由于缺氧可能不是由于原位异养过程引起的，缺氧水可能来自上游。我们推测这是因为 DO 与盐度相关（R=0.664，df=86，p<0.001）。DO 也随着冲洗时间的增加而降低（R=0.556，df=11，p<0.01），表明当冲洗时间（>6.7 小时）时，巴生河口可能会出现缺氧现象。在这里，我们提出了一个将河川流量与强降雨后缺氧相关联的模型，该模型解释了巴生河口的间歇性缺氧现象。由于巴生河口支持水产养殖和蛤养殖，我们的研究结果有助于保护这里的水产养殖和蛤养殖产业。
