Ocean acidification changes balance of biofouling communities

There is overwhelming evidence to suggest the world's oceans are becoming, and will continue to become more acidic in the future, but there are many questions about how it will affect marine life. The 'biofouling community' – consisting of tiny species like sea squirts, hard shell worms and sponges – affects many industries including underwater construction, desalination plants and ship hulls. Removing these organisms (a process called antifouling) is estimated to cost around $22 billion a year globally.

For the first experiment of its kind, over 10,000 animals from the highly productive Ria Formosa Lagoon system in Algarve, Portugal were allowed to colonise hard surfaces in six aquarium tanks. In half the tanks, the seawater had the normal acidity for the lagoon (PH 7.9) and the other half were set at an increased acidity of PH 7.7. The conditions represented the IPCC's prediction for ocean acidification over the next 50 years.

After 100 days, animals with hard shells (Spirobid worms – Neodexiospira pseudocorugata) reduced to only one fifth of their original numbers, while sponges and some sea squirts (Ascidian Molgula sp) increased in number by double or even fourfold.

Lead author Professor Lloyd Peck from British Antarctic Survey (BAS) says:

“Our experiment shows the response of one 'biofouling community' to a very rapid change in acidity, but nonetheless shows the degree to which these communities could be impacted by ocean acidification, and to which its associated industries may need to respond.

What's interesting is that the increased acidity at the levels we studied destroys not the building blocks in the outer shell of the worms itself, but the binding that holds it together. Many individuals perish, but we also showed their larvae and juveniles are also unable to establish and create their hard exoskeleton.”

Professor Peck continues, “Although a PH reduction of 0.2 is less than the IPCC's 'business as usual' scenario of PH 0.3 – 0.4 in ocean surface waters by 2100, it will likely be achieved between 2055 and 2070.”

Author, Dr. Deborah Power, from Centro de Ciências do Mar says: “Taking into consideration the importance of the Ria Formosa lagoon as a natural park the modified community structure driven by a reduction in PH, while potentially reducing biofouling issues, will almost certainly affect lagoon productivity and impact on biodiversity.”

###

The study was carried out by scientists from British Antarctic Survey, Centro de Ciências do Mar, Instituto Portugues do Mar e da Atmosfera and University of Cambridge.

Issued by the British Antarctic Survey Press Office.

Contact: Athena Dinar: Tel: +44 (0)1223 221441, +44 (0)7909 008516 email amdi@bas.ac.uk

Paul Seagrove: Tel: +44 (0)1223 221414, +44 (0)7736 921693 email: psea@bas.ac.uk

Photos of the experiment plates are available from the BAS ftp site: ftp://ftp.nerc-bas.ac.uk/pub/photo/biofouling-community/

NB: to download do not use an FTP client, simply open in any web browser (firefox/IE etc) right click on the filename and select 'save target/link/file as' to begin the download

Notes for editors

Acidification effects on biofouling communities: winners and losers by Lloyd S. Peck, Melody S. Clark, Deborah Power, João Reis, Federico M. Batista and Elizabeth M. Harper is published in the journal Global Change Biology on 28 January 2015.

Biofouling or biological fouling is the accumulation of microorganisms, plants, algae or animals on wet surfaces. Since biofouling can occur almost anywhere water is present, biofouling poses risks to a wide variety of objects such as medial devices and membranes, as well as to entire industries such as paper manufacturing, food processing, underwater construction, and desalination plants. The build up of biofouling on marine vessels poses a significant problem. The hull structure and propulsion systems can be damaged and over time, accumulated build up can increase the hydrodynamic volume of a vessel and the frictional effects leading to an increased drag of 60%.

In the study Spirorbid worm numbers decreased x5.5 (from 11.1 per 10square cm to 2.0). Molgula numbers increased x4.1. Sponge numbers (Leucosolenia sp.) increased x2.5.

The Ria Formosa is one of the most amazing places of the Algarve, not only for its variety of landscapes but also because of its unique location. Recently elected as one of the seven Natural Wonders of Portugal, this unique coastal lagoon is constantly changing due to the continuous movement of winds, currents and tides. Classified as a Natural Park in 1987, the Ria Formosa encompasses an area of about 18 000 hectares, and is protected from the sea by five barrier-islands and two peninsulas. The biofouling community in this location were chosen for their ability to develop quickly in its warm waters.

This work was funded by the Natural Environment Research Council (NERC) and an EU Research Infrastructure Action under the FP7 'Capacities' Specific Programme.

British Antarctic Survey (BAS), an institute of the Natural Environment Research Council (NERC), delivers and enables world-leading interdisciplinary research in the Polar Regions. Its skilled science and support staff based in Cambridge, Antarctica and the Arctic, work together to deliver research that uses the Polar Regions to advance our understanding of Earth as a sustainable planet. Through its extensive logistic capability and know-how BAS facilitates access for the British and international science community to the UK polar research operation. Numerous national and international collaborations, combined with an excellent infrastructure help sustain a world leading position for the UK in Antarctic affairs. For more information visit: http://www.antarctica.ac.uk.

Centro de Ciências do Mar (CCMAR), is an independent multidisciplinary, non-profit research organization within the University of Algarve system, with the mission to promote research and education on processes in the marine environment, with emphasis on biological interactions and the sustainable use of resources. The CCMAR research community is a dynamic mix of research groups integrating researchers in well-established and emerging fields. CCMAR is one of the foremost marine science research centres in Portugal, and facilitates access to services and facilities in marine science, aquaculture and biotechnology. It has extensive national and international collaborations and is a node of the European Marine Biological Resource Centre (EMBRC, http://www.embrc.eu) an ESFRI infrastructure and also part of the national nodes of ELIXIR (http://www.elixir-europe.org) and EMSO (http://www.emso-eu.org/). For more information visit: http://www.ccmar.ualg.pt