The future of seaweed aquaculture in a rapidly changing world

Human activities are having increasingly negative impacts on the natural environment. The rapidly expanding human population has led to a shortage of resources and the ability to support the growing population sustainably is a major challenge for the future. Coastal environments, including natural seaweed communities, provide a range of important ecosystem services. Since seaweed aquaculture beds (SABs) provide many of the services associated with natural seaweed communities they have a potential role in providing solutions such as CO2 sequestration, provision of food and the supply of useful chemicals. However, the productivity of natural seaweed communities and SABs is under threat from the rapid changes in climate that the planet is experiencing. Here we examine the likely effects of global change, in particular elevated CO2 and ocean acidification, increased temperatures and elevated levels of UVB, on the performance of seaweeds. While it is clear that rising temperatures and elevated CO2 and their interactions with other environmental factors are likely to have profound effects on macroalgal production, such effects are likely to be species dependent. We also examine the fate of organic matter from seaweeds and the potential for using SAB productivity as a contributor to blue carbon as a strategy for amelioration of increases in anthropogenic CO2 emissions. There is considerable potential for increased drawdown of CO2 by SABs, though its effectiveness in amelioration of atmospheric CO2 increase will depend on the fate of the resulting biomass.