Anthropogenic nutrient inputs affect productivity-biodiversity relationships in marine tintinnid assemblages

Although the productivity-biodiversity relationship (PBR) has been a hot topic, few studies have considered how anthropogenic pressures affect PBRs in marine microzooplankton. Here, we provide the first insights into PBRs in tintinnid assemblages using 18-year data from Jiaozhou Bay, a typical coastal bay in the Yellow Sea. We hypothesized and verified that PBRs vary across contrasting anthropogenic nutrient inputs and that functional and phylogenetic diversity would deliver more information than conventional species richness. High productivity promotes more diversity under low to medium rather than high anthropogenic nutrient inputs. Compared to species richness, functional and phylogenetic diversity reveals more PBR patterns and responds more quickly in response to varying anthropogenic inputs. A concave+ PBR is revealed for functional diversity in the ecozone with highly active water exchange. Our study contributes to the understanding of PBR in marine unicellular secondary producers and their responses to anthropogenic nutrient inputs in coastal ecosystems.