Cultural Eutrophication
Following the previous post, I was interested to find out more about how the Yangtze River contributes to eutrophication in the East China Sea. While researching more on the topic, I came across a journal article by Wang (2006), which is accessible below, that offered substantial insights on cultural eutrophication in the Yangtze River plume.
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Open in new tab Eutrophication is a natural process, whereby water bodies experience an increase in productivity due to increased nutrient concentrations. This can be enhanced by human activities, such as agriculture production wherein runoff and discharge into the river can also aid in increasing the concentration of nutrients, particularly nitrogen and phosphorus. Human activities-induced eutrophication is also known as cultural eutrophication. This is a significant phenomenon in the Yangtze River Basin as agricultural activities have increased immensely over the years. The Yangtze River also acts as a transportation medium, transporting the nutrients into the river plume, and even to the East China Sea.
Wang (2006) found that dissolved inorganic nitrogen and phosphate concentrations in the Yangtze River were 500% higher in the 1990s than in the 1960s. This was coupled with a decrease in dissolved silicate concentrations in the Yangtze River by 66%. Similar patterns were observed in the Yangtze River plume, with dissolved inorganic nitrogen and phosphate concentrations increasing by 200% and dissolved silicate concentrations decreasing by 50%. This change in nutrient concentrations resulted in a higher chlorophyll concentration, facilitating the increase in harmful algal blooms in the Yangtze River, the Yangtze River plume, and the East China Sea. Impacts of harmful algal blooms include oxygen depletion of surface waters and the release of toxins. It is expected that nutrient concentrations in the Yangtze River will continue to increase, which will worsen the impacts associated with eutrophication in the Yangtze River plume.
References
Wang, B. (2006). Cultural eutrophication in the Changjiang (Yangtze River) plume: History and perspective. Estuarine, Coastal and Shelf Science, 69(3–4), 471–477. https://doi.org/10.1016/j.ecss.2006.05.010