Response of marine benthic ecosystem function to global change

Marine benthic ecosystems are the locations of a wide range of important processes, including Carbon cycling and nutrient re-cycling. Although shallow marine environments such as estuaries and shelf seas only cover ~5% of the seafloor, they are responsible for 15-20% of marine production1, and large proportions of the turnover of other bioelements. In such environments the benthic fluxes of C, N and P have the potential to exert controls on water quality and productivity in the overlying water column. Estuarine sediments are also one of the most important locations for long term burial of organic C in marine sediments (so called ‘blue carbon’). Therefore biogeochemical processes in shallow marine benthic settings provide important ecosystem services, and influence the quality of an environment which supports many important human activities.

Increasing atmospheric CO2 concentrations have already led to increases in sea surface temperatures and decreasing seawater pH3, and these trends are forecast to continue into the future. In addition, due to reduced solubility of gases and increased thermal stratification, it is expected that the incidence of hypoxia (low dissolved oxygen concentrations) in marine environments will spread4. Shallow marine benthic environments are particularly vulnerable to these changes.

Temperature, oxygen availability and pH are known to have marked effects on the way that benthic ecosystems function5, 6, 7, however the effect of these factors on the full range of biogeochemical processes is lacking. Furthermore, the effect of altering these important environmental factors is likely to depend on sediment type and season. Finally, most experiments so far have concentrated on manipulating only one key factor, however combinations of factors are likely to have greater impacts on ecosystem functioning than the sum of individual factor manipulations, and this warrants full investigation.

Project Goals and Outline

This studentship will address the question how does marine benthic biogeochemical functioning respond to future temperature, oxygenation and pH conditions, and how does that response depend on initial environmental characteristics?

For further details, please see http://www.nercdtp.leeds.ac.uk/projects/index.php?id=535 or contact Dr Clare Woulds with enquiries ([Email Address Removed])