This is a the first of a series of fortnightly articles featuring seagrass meadows around the world. This week, Dorothée Pête of the University of Liege takes us to Calvi Bay in Corsica, which is one of her research field sites.
By Dorothée Péte

Although it’s nearest water body is the river Meuse, the University of Liege in Belgium has always had a strong interest in marine sciences. To strengthen the link between Liege and the sea, a research station was built in the late sixties, in Calvi Bay in Corsica, France. This research station with a catchy acronym – STARESO which stands for STAtion de REcherches Sous-marines et Océanographiques – which in English means “Station for underwater and oceanographic research” is a base for marine research carried out by the University.

Map of Calvi Bay (taken from Google Earth) showing the locations of STARESO, Punta Oscellucia, sewage outfall area, zone where Caluerpa racemosa was identified and location of fish farms. and other seagrass sites in the locality.

Calvi Bay is a wonderful place for studying seagrasses in the Mediterranean. It has two species of seagrasses, Posidonia oceanica (which is endemic to the Mediterranean Sea) and Cymodocea nodosa. This bay is of particular interest because all the major threats present in the Mediterranean Sea can be found in such a small area – making it a natural choice for studying impacts via field experiments. Plus, the view is spectacular both above and below water so you can easily understand why our lab (Laboratory of Oceanology) is working there and why I wanted to write a note to explain our field work.

Calvi Bay, Corsica - the view above water

Let’s begin with the STARESO. In front of the research station, you can find a continuous meadow of P. oceanica. This seagrass canbe found from near the surface (5 m depth in STARESO) to about 40 m depth, so scuba diving is essential if you want to work in this meadow. The meadow at the STARESO site is a reference one, thanks to its good state of health. Our lab has been following it for years, with a particular focus on the seagrass itself (its growth, density and leaf litter accumulations), but also on its epiphytes, nutrients and trace elements contents, food webs and on organisms living in the sediment. Of course, environmental parameters such as nutrients in surrounding and pore waters and temperature are monitored as well. The meadow is also part of the SeagrassNet monitoring program. In situ experiments like shading, microcosms, sediment loading and nutrients and trace elements dynamics (e.g. inside isolated jars) are being carried out there too.

Studies being carried out in Calvi Bay (from L-R): Nutrient dynamics, microcosm experiments and shading experiments

Just next to STARESO, near Punta Oscellucia, large amount of underwater leaf litter accumulations are present and are exported onto the surrounding beaches and there are currently studies focused on the dynamics of those litter patches and organisms living inside them.

Seagrass wrack accumulations off Punta Oscellucia

Sadly, it’s not all about beautiful seagrass and crystal clear waters in Calvi Bay as there are quite a number of threats in the area. It is widely known that the Mediterranean Sea is a major tourist attraction and a hub for marine recreation. In summer, tourists from all over the world invade the city of Calvi, causing direct stress to the seagrasses there through activities such as yachting but also indirectly due to increased sewage, which is another important (although slightly less glamorous) topic that our lab is studying by looking at the zones of the seagrass meadow situated near the sewege outfalls from Calvi.

Fish farming activities have been increasing in the Mediterranean Sea, and Calvi Bay has a small aquaculture industry. It is situated above a P. oceanica bed but it is fortunately quite well managed, so the impact on the meadow is very small. However, we are also studying the P. oceanica ecosystem in that zone for a better understanding of fish farming impacts.

Fish Farms floating in the waters off Calvi Bay.

The last (but not least!) threat that was identified very recently in Calvi Bay is the presence of an invasive seaweed species Caulerpa racemosa. We are just beginning to work on that subject and for now, it looks like it shouldn’t be a problem for P. oceanica in that zone. However, in other parts of the Mediterranean Sea, invasive seaweeds are causing more and more troubles to seagrass meadows. They are taking over areas formerly colonized by large beds of seagrasses and seem more resistant to environmental impacts than the seagrasses. In that way, they are becoming a threat for the coastal biodiversity of the Mediterranean by causing modifications in the habitats of numerous organisms (some of which are commercially important species) and a switch in communities, leading to a decrease in biodiversity.

I hope that I have convinced you how lucky we are to have such a nice site for field work, but if you want to see more and learn more about STARESO and the awesome people in my lab working seagrasses, please visit our website and check out the links below:

Laboratory of Oceanography, University of Liege:





Thanks to Klemens Gann, the WSA would like to share this seagrass video from the Philippines. If you have video you would like to share, please let us know.


To access the video click on the link below, and Enjoy!

Seagrass Symphony



World Oceans Day

Raising the voice for the world’s seagrass on World Oceans Day

Seagrass meadows around the world continue to be under threat from the activities of humans. Over fishing, climate change, coastal development, extreme weather and poor land management are all contributing to the continued global loss of these diverse and productive marine habitats that are critical for the continued functioning of the coastal environment and the services it provides.

Over the last decade a range of publications by leading global scientists have highlighted how governments, communities, industry and global conservation are failing to take the action necessary to prevent the further degradation of these important ecosystem service providers. Recent high profile research publications have shown how individual seagrass species are potentially under threat from extinction, whilst the global area of seagrass is being reduced at a rate of up to two soccer fields per hour.

Seagrass meadows are a valuable means of support for global food security due to their role as critically important nursery habitats for many of the world’s fisheries. They also directly provide fishery habitat and support endangered species such as the dugongs and green turtles. Seagrass meadows bubble oxygen into the water and sediments, sucking carbon dioxide from the atmosphere and cleaning the coastal environment of many pollutants.  If current patterns of habitat loss coupled to the increasing influence of climate change are not controlled then the world faces a  potentially future devoid of these productive, valuable and diverse habitats.

Not many people know what a seagrass meadow is, but it’s estimated that 1 billion people live within 50 km of one. Today, on World Oceans Day, scientists from the World Seagrass Association are seeking to highlight the value and threats to these meadows so that greater emphasis and resources are placed on their conservation.

To help save seagrasses into the future the World needs to:

  • educate people about the importance of seagrasses through ad-hoc awareness programs;
  • decrease turbidity in coastal waters by reducing sediment and nutrient loads being released from land;
  • make sure boats no longer damage seagrasses via their anchors or propellers;
  • prohibit dredging and filling on/nearby areas colonized by seagrasses;
  • preserve existing seagrass beds and restore degraded or lost ones; and
  • include seagrass ecosystems in coastal management plans or marine protected areas.

General information on seagrass


Seagrasses in South Florida, the Florida Museum of Natural History

Seagrasses at CoSEE (The Centers for Ocean Sciences Education Excellence, University of Maryland Center for Environmental Science

Mediterranean Seagrass Ecosystem at MarBEF (Marine Biodiversity and Ecosystem Functioning)

Key seagrass publications

Unsworth and Cullen (2010). “Recognising the necessity for Indo-Pacific seagrass conservation.” Conservation Letters 3(2): 63-73. Follow the link

Hughes et al (2009). “Associations of concern: declining seagrasses and threatened dependent species.” Frontiers in Ecology and the Environment 7(5): 242-246. Follow the link

Waycott et al. (2009). “Accelerating loss of seagrasses across the globe threatens coastal ecosystems.” Proceedings of the National Academy of Sciences of the United States of America 106(30): 12377-12381. Follow the Link

Duarte et al. (2008). The charisma of coastal ecosystems: addressing the imbalance. Estuaries and Coasts 31: 233–238 Follow the link

Orth et al (2006). A Global Crisis for Seagrass Ecosystems. Bioscience 56: 987–996 Follow the link

Frederick T. Short, Beth Polidoro, Suzanne R. Livingstone, Kent E. Carpenter, Salomão Bandeira, Japar Sidik Bujang, Hilconida P. Calumpong, Tim J.B. Carruthers, Robert G. Coles, William C. Dennison, Paul L.A. Erftemeijer, Miguel D. Fortes, Aaren S. Freeman, T.G. Jagtap, Abu Hena M. Kamal, Gary A. Kendrick, W. Judson Kenworthy, Yayu A. La Nafie, Ichwan M. Nasution, Robert J. Orth, et al. 2011. Extinction risk assessment of the world’s seagrass species. Biological Conservation, 144: 1961-1971

By Miguel Fortes

It is only very recently that the importance of protecting and restoring seagrass habitats has been clarified as a climate change mitigation strategy. Towards this end, Conservation International, IUCN, IOC‐UNESCO and partners are “building a program to coordinate and guide establishment of coastal ‘blue’ carbon as a conservation and management tool contributing to climate change mitigation and the development of associated conservation financing mechanisms”. The initial action in order to realize the program was the formation in February 2011 of the “Blue Carbon” International Scientific Working Group.

The group is tasked to:

  1. Develop coastal marine conservation and management approaches that maximize sequestration of carbon and avoided emissions in coastal systems.
  2. Design and implement the program of work for carbon accounting in coastal systems and in turn developing economic incentives
  3. Coordinate with and synthesize other related existing science and policy activities
  4. Identify relevant pilot field projects, and provide guidance, technical advice, and support to the pilot projects.
  5. Identify essential science gaps for research programs

Five of the 22 members of the working group are well known to us in the WSA and seagrass circle: Carlos M. Duarte, Miguel D. Fortes, Jim Fourqurean, Nuria Marba, and Peter Ralph. The working group is convened by Conservation International, International Union for Conservation of Nature, and the UNESCO Intergovernmental Oceanographic Commission. The Waterloo Foundation, NASA and UNEP have provided funding for the group.

The initial recommendations of the group are coming out soon in a pamphlet: “Minimizing Carbon Emissions and Maximizing Carbon Sequestration and Storage by Seagrasses, Tidal Marshes, Mangroves”. They embody the immediate steps that need to be taken by coastal communities, managers, policy makers and the scientific community. In brief, these steps are:

  1. Enhanced national and international research efforts—building on existing scientific data, analysis, and available technologies, a coherent and programmatic global data gathering and assessment effort is needed.
  2. Enhanced local and regional management measures—current knowledge of the carbon sequestration potential of coastal wetlands and emissions from drained systems is sufficient to warrant enhanced management actions now.
  3. Enhanced international recognition of coastal carbon ecosystems—current international actions to reduce the impacts of climate change do not recognize the greenhouse gas emissions resulting from the degradation of coastal wetlands or the role of healthy coastal ecosystems in sequestering carbon dioxide.
Photo courtesy of M. Fortes

A healthy mixed species seagrass meadow in Ilog Malino, Bolinao, Philippines. Photo courtesy of M. Fortes

Photo courtesy of M. Fortes

Bleached seagrass meadow in Ilog Malino, Bolinao, Philippines. Photo courtesy of M. Fortes

At the moment, the group is developing the Global Coastal Carbon Data Archive.

For more information:

Blue Carbon Report

Recommendations from the 1st meeting of the Blue Carbon Scientific Working group

Blue Carbon blog

Membership Survey

Please take the time to provide feedback via the Membership Survey

In November 2010 a new committee was elected, and the WSA has a new President in Dr Giuseppe Di Carlo and a range of new and younger members involved. The committee felt that the WSA needed a fresh approach to reaching out to its members in order to fulfil its potential as the leading global network of seagrass scientists and coastal managers. The new WSA committee now needs to gain the support of the membership and develop a strategy for the future direction of the Association.

In order to galvanise support for the WSA, and to develop new initiatives and ideas, it was felt that providing a questionnaire to all members would be a valuable process. It was felt that this was a way of capturing ideas throughout the association and reaching out to the membership to engage individuals about the needs of the seagrass conservation and research community that the Association can help address and/or support.

We would therefore request the assistance of all members by completing the following questionnaire. While we understand that you are all busy in your respective activities we ask you to take half an hour to consider how you feel the WSA can develop into the future.

Please remember the strength of the Association is in the commitment of its members. Thanking you in advance.

WSA Management Committee

We are conducting this survey via the online tool Survey Monkey, all responses will remain anonymous. All members will receive an email with a link to the survey—if you didn’t receive (or have mislaid) your invitation to participate contact us and we’ll resend your details (send an email to resources at seagrassonline.org).

Len McKenzie

« Newer Posts - Older Posts »