Abstract: The impact of high siltation and
accumulation of organic and waste material in the intertidal of the dammed Ba
Lai River in Vietnam as
part of the Mekong estuarine system was investigated by means of marine
free-living nematodes. Nutrients content (nitrate, ammonium, total phosphorus,
total nitrogen), total suspended solids, total organic carbon, coliform,
bacteria E. coli, pH, dissolved oxygen, total dissolved solids,
methane and hydrogen sulfide concentration, and the nematode communities were
characterized in sediment at selected stations along the river above and below
the dam. Our results found elevated methane concentrations at the upstream side
of the dam while hydrogen sulfide concentrations found to be highest in the downstream
side of the dam. Furthermore, methane and hydrogen sulfide concentrations were
correlated to nematode community characteristics such as trophic composition
densities and genera composition. There was a clear difference between the
communities above and below the dam. The discontinuous nematode community
distribution indicated that the Ba Lai River is impacted by dam construction.
Potentially the high deposition and eutrophication could turn the area into a
methane-rich area related to predicted impact on nematodes.
Fulltext: https://doi.org/10.1007/s10661-022-10187-5
