Benthic biodiversity near brine discharge sites in the Port of Rotterdam

The Port of Rotterdam is a heavily man-modified estuarine system, Europe's major seaport and home to large number chemical petrochemical plants, many which are supplied with distilled water from two demineralized plants in Botlek Maasvlakte. In this study, we assessed the ecological conditions near brine outfalls at reference site unimpacted by brine, focusing on benthic macrofaunal composition. Overall, analysis communities species revealed similar macrobenthic composition, although lower abundance diversity compared nearby North Sea environment. outfall area plant, dead-end entirely marine waterway no little currents contrast well flushed brackish environment Maasvlakte was characterized lowest macroinvertebrates, richness Shannon index. Higher biodiversity values plant were also associated presence biogenic reef Pacific oyster Crassostrea gigas specimens over 8 years estimated age being observed, however dead individuals recorded time surveys. had highest disturbance levels according results AZTI's Marine Biotic Index (AMBI) conjunction Benthos Ecosystem Quality (BEQI). Its community dominated opportunistic native Capitella capitata Varicorbula gibba, typical for organic matter enrichment such as Alitta succinea (native), Streblospio cf shrubsolii (native) Theora lubrica (invasive), correlates higher anthropogenic pollution area. Generalized linear model (GLM) distance-based multivariate (DistLM) showed that distance an important factor terms impacts explaining small part variation observed. Similarity percentage (SIMPER), analysis, permutational (PERMANOVA) low similarity between within study sites, confirming high heterogeneity exist system natural stress.