July 22, 2015
by Lyndsay Cruickshank
We’ve all seen the banner headlines about CO2 concentrations increasing in the atmosphere, but did you know this increase is also impacting our seas and its inhabitants too?
There is a natural exchange of CO2 between the surface layers of the ocean and the atmosphere. The chemistry of seawater is complex, an imbalance as a result of absorption of atmospheric CO2, by oceans, has the potential of making the seawater more acidic, this is known as Ocean Acidification.
It has been reported that a third of the CO2 from human activities (such as fossil fuel burning) produced over the past 200 years has been absorbed by the oceans, resulting in a decrease in pH level. Changing the acidity of sea water may have an impact on many living organisms in the sea such as plankton. Plankton are most active near the ocean surface (the upper 200 m), and this layer is likely to be the most affected by ocean acidification, and any impact on plankton may affect other parts of the food chain.
Some marine regions will be more rapidly affected, therefore it is important to routinely monitor for changes in CO2 concentrations.
What is Marine Scotland Science Doing?
We are involved in a number of projects to assess changes to Scottish waters as a result of increasing CO2 in the atmosphere. Since 2009 water samples have been collected from two depths (one and 45 m) on a weekly basis (weather permitting) at the Stonehaven ecosystem monitoring site with the aim of providing a baseline for a coastal region in Scottish waters. Water samples collected between January 2009 and August 2011 were collected and analysed, by the National Oceanography Centre Southampton (NOC), as part of the Defra PH project and UK Ocean Acidification (UKOA) project. Since September 2011 water samples have been collected at Stonehaven as part of the Stonehaven ecosystem monitoring programme were we have collected monthly water samples for coccolithophore identification.
Coccolithophores are microscopic phytoplankton which are covered in calcareous plates. Laboratory studies to investigate the impacts of OA on this part of the plankton community have given conflicting results. Understanding the seasonal control of Emiliania huxleyi diversity and calcification will contribute to a better understanding of the potential biological impact of OA on coccolithophores in Scottish waters. Marine Scotland has just started a small project investigating if pteropods (small marine snails that live in the water column) can also be used to assess the impacts of OA on the marine plankton community.
The data from the coastal site continues to be of particular interest both nationally and internationally, as this is one of the few international long-term weekly baseline monitoring sites for OA studies. Linked with the biological data this site provides valuable information to help us understand and distinguish long-term anthropogenic signals from short-term spatial and temporal variability.
Pamela Walsham, Lynda Webster, Eileen Bresnan and Pablo Leon Diaz
Marine Scotland Science International Representation
Marine Scotland Science has international representation on a number of groups, we are network members of the Global Ocean Acidification – Observing Network (GOA-ON) and were a member of the Joint OSPAR/ICES Ocean Acidification Study Group (SGOA 2012-2014). A MSS staff member will be one of the conveners for Theme session H: Ocean acidification: Understanding chemical, biological and biochemical responses in marine ecosystems of the ICES ASC 2015.