The influence of estuary eutrophication on the benthic diatom community: a molecular approach

The occurrence of harmful algal blooms (HABs) is increasing in frequency and intensity South African estuaries because eutrophication. This study used DNA metabarcoding to identify the benthic diatom community structure eutrophic Sundays Estuary. recurrent HAB phytoplankton species Heterosigma akashiwo was recorded at bloom concentrations (?100 µg Chl a l?1) brackish, vertically stratified middle reaches estuary. In contrast, microphytobenthos biomass increased towards upper response elevated availability total oxidised nitrogen (NOx) sediment stability. A 76 were identified using molecular technique. Seven known nutrient-tolerant indicate preference for either ammonium or NOx enrichment. Benthic diversity (H? < 1) evenness (J? 0.25) low brackish estuary, where HABs decreased available light. has been found previous studies suppress growth co-occurring taxa. Future research efforts should focus on verifying this relationship over seasonal timescales given dominance H. spring/summer. As persistently nutrient-enriched state stable flow conditions Estuary key driver change, management be geared re-establishing estuary’s natural variations measures that can mitigate nutrient pollution.