Escape from the North Sea: the possibilities for pikeperch (Sander lucioperca L. 1758) to re-enter the Rhine and Meuse estuary via the Haringvlietdam, as revealed by telemetry

Brevé, Niels; Vis, Hendry; Breukelaar, A. W.

doi:10.1007/s11852-018-0654-5

Cited by 2 publications

(1 citation statement)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The estuary experiences a dominant semidiurnal tide, with a tidal range varying from 0.4 m during low tide to 2.0 m maximum during high tide. Short-term dam opening experiments were conducted in 2019, while long-term dam opening experiments were carried out in 2020 and 2021 (Brevéet al, 2019;Baird et al, 2020;An, 2021;van den Tweel et al, 2021). In 2019, two short-term dam opening experiments took place on June 6 and September 17, involving approximately 0.64 and 1.01 million tons of seawater respectively, flowing upstream of the Nakdong River for 38 minutes and over 1 hour (An, 2021).…”

Section: Sampling Sites and Protocolmentioning

confidence: 99%

Seawater intrusion effects on nitrogen cycling in the regulated Nakdong River Estuary, South Korea

Huang,

Song,

Zhang

et al. 2024

Front. Mar. Sci.

View full text Add to dashboard Cite

Research on the impact of seawater intrusion on nitrogen (N) cycling in coastal estuarine ecosystems is crucial; however, there is still a lack of relevant research conducted under in-situ field conditions. The effects of elevated salinity on N cycling processes and microbiomes were examined in situ seawater intrusion experiments conducted from 2019 to 2021 in the Nakdong River Estuary (South Korea), where an estuarine dam regulates tidal hydrodynamics. After the opening of the Nakdong Estuary Dam (seawater intrusion event), the density difference between seawater and freshwater resulted in varying degrees of seawater trapping at topographically deep stations. Bottom-water oxygen conditions had been altered in normoxia, hypoxia, and weak hypoxia due to the different degrees of seawater trapping in 2019, 2020, and 2021, respectively. Denitrification mostly dominated the nitrate (NO3-) reduction process, except in 2020 after seawater intrusion. However, denitrification rates decreased because of reduced coupled nitrification after seawater intrusion due to the dissolved oxygen limitation in 2020. Dissimilatory nitrate reduction to ammonium (DNRA) rates immediately increased after seawater intrusion in 2020, replacing denitrification as the dominant pathway in the NO3- reduction process. The enhanced DNRA rate was mainly due to the abundant organic matter associated with seawater invasion and more reducing environment (maybe sulfide enhancement effects) under high seawater-trapping conditions. Denitrification increased in 2021 after seawater intrusion during weak hypoxia; however, DNRA did not change. Small seawater intrusion in 2019 caused no seawater trapping and overall normoxic condition, though a slight shift from denitrification to DNRA was observed. Metagenomic analysis revealed a decrease in overall denitrification-associated genes in response to seawater intrusion in 2019 and 2020, while DNRA-associated gene abundance increased. In 2021 after seawater intrusion, microbial gene abundance associated with denitrification increased, while that of DNRA did not change significantly. These changes in gene abundance align mostly with alterations in nitrogen transformation rates. In summary, ecological change effects in N cycling after the dam opening (N retention or release, that is, eutrophication deterioration or mitigation) depend on the degree of seawater intrusion and the underlying freshwater conditions, which constitute the extent of seawater-trapping.

show abstract

Section: Sampling Sites and Protocolmentioning

confidence: 99%