Data from: Benthic community history in the Changjiang (Yangtze River) mega delta: Damming, urbanization, and environmental control
Cheung, Ching Wa Richard et al. (2019), Data from: Benthic community history in the Changjiang (Yangtze River) mega delta: Damming, urbanization, and environmental control, Dryad, Dataset, https://doi.org/10.5061/dryad.39121ns
Coastal environment of the Changjiang delta has been influenced by recent anthropogenic activities such as dam constructions, and increased sewage and fertilizer inputs. Previous work examined compositional shift of marine plankton to assess ecological impacts of these activities on marine ecosystems in the Changjiang discharge area. Here we used benthic marine ostracodes collected in the Changjiang Estuary and its adjacent East China Sea in the 1980s and the 2010s, respectively, to investigate temporal changes of the benthic community and the controlling factors of the benthic fauna. Our results revealed more shoreward distribution of some well-known off-shore ostracode species in the 2010s compared to the 1980s, and relatively more important role of environmental processes (e.g. bottom water temperature, bottom water salinity and the eutrophic conditions of surface water) than spatial processes (e.g. the flow of ocean currents) in structuring ostracode compositions. The temporal changes of ostracode community were likely attributed to the combined effects of reduced seasonal water and sediment discharge, and eutrophic conditions of the Changjiang due to numerous dam constructions along the Changjiang and population expansion in the Changjiang basin. Results of redundancy analysis and variation partitioning suggested that ocean currents facilitated environmental filtering of ostracode species such that they could disperse to preferred environmental conditions. These findings highlighted the potential uses of marine microfossils to better understand ecological impacts on benthic ecosystem in vulnerable Asian mega deltas and provided insights into the integration of metacommunity concepts in disentangling dynamics of marine benthic communities.
East China Sea