Kelp's heating up!
Published: 15 February 2017
We know that marine ecosystems provide a large number of ecosystem services that are dependent on their biodiversity and ecological functioning. Environmental change, including increased temperatures and storminess, threaten to alter these ecological functions and services. Globally, primary production (energy harnessed from the sun) is dominated by phytoplankton (microscopic marine organisms) in marine ecosystems.Recent studies, however, estimate that macrophytes (large plants) contribute 45% of primary production in UK coastal waters. Most of this macrophyte production is from brown seaweeds known as kelp. Highly productive kelp beds support high secondary production (animals that eat seaweed) and are ecosystem engineers forming habitat for other organisms and creating biodiversity hotspots, which includes many commercially important species. Despite this potential importance, kelp-derived production is not included explicitly in most marine ecosystem models, and their functional role in coastal food webs is understood poorly.
At Queen’s University Belfast (QUB) we are conducting surveys and field experiments to estimate kelp production rates at several sites on exposed and sheltered shores in Ireland. This will help increase our understanding of how fast it grows, how much is eaten directly, how much is broken off due to storms, how fast it breaks down as detritus and where it goes. We have also been working to develop novel method for manipulating temperatures in the field.
With the assistance of engineers from QUB, kelp heating plates have been developed, which will allow temperatures in and around intertidal seaweed to be artificially increased. This development will, for the first time, allow us to manipulate temperatures on whole seaweed communities in situ. The method is aimed to help validate ecological models and laboratory experiments that investigate the effects of elevated temperatures on primary productivity in intertidal systems.
A prototype has already been placed in the field, with full deployment anticipated to occur in the coming months. We have also been busy analysing data, which were collected over a latitudinal gradient, in Ireland and with collaborators in Portugal, in order to assess how large-scale environmental variability influences the primary productivity of seaweed. Understanding these processes and the factors that regulate them will enable the development of management plans that are vital for long-term sustainability of natural resources.