Large-Scale Environmental Drivers of Kelp Biofouling Based on Literature Data

Abstract

Macroalgae are increasingly studied for their critical contributions to coastal ecosystems, their potential to mitigate climate change, and their promise as a sustainable food source. While wild macroalgae host diverse epiphytic and invertebrate epibiont communities that enhance biodiversity and ecosystem functioning, biofouling epibionts on farmed macroalgae can negatively impact growth, physiology, and product quality. Although an increasing number of longitudinal studies are trying to establish the drivers of macroalgae biofouling, localized approaches lack sufficient contrasts in environmental conditions to reveal macroecological patterns in epibiont occurrence. To gain these contrasts, we analyze data on macroalgae and epibiont taxonomy, study location, and environmental conditions that we have compiled from a systematic literature review and from Marine Copernicus and NASA-OBPG databases of marine data. Our results show that 58.18% of macroalgae epibiont studies focus on the North-East Atlantic coast, which is particularly useful in understanding the potential for the expansion of seaweed aquaculture in this region. Bryozoan fouling depends on sea surface temperature (SST) and an increased biofouling risk was predicted for latitudes greater than 58° in the NE Atlantic coast and around coastal areas in Scotland with cold freshwater inflows. Hydrozoans and gastropods showed a higher probability of occurring on farmed or planted as opposed to wild kelp, whereas gastropods tended to be absent at salinities lower than 30 psu. Our findings provide a first basis for understanding seaweed biofouling risks in the North-East Atlantic and can serve for the spatial planning of the positioning of new seaweed farms.