Moderate growth of green algae helps survival of seagrass meadows against excess of nutrients

For many years, the uncontrolled anchoring of leisure boats and illegal fishing practices, pollution and water turbidity due to agriculture and aquaculture activities, as well as works and constructions engineering activities on the coast, have modifiedy the littoral, and have made these seagrass meadows to be at stake. In addition, excessive nutrients generated by many factors encourage sea lettuce, which negatively affect the viability and development of these marine angiosperms.

Concerning this last point, the development of the so called green tides and how thisese affects marine phanerogams seagrass meadows, researchers from the University of Cadiz, making up the group of Structure and Dynamics of Aquatic Ecosystems (EDEA), led by Professor Juan Jose Vergara, have made a study which has been published in the international journal Plos One. This study states that a certain quantity of these algae may be beneficial for the marine phanerogams seagrasses when there are too many nutrients in the environment (i.e. ammonium). That is to say that a moderate presence of algae, instead of damaging marine phanerogamsseagrasses, could be helpful to their survival, as the algae may reduce the direct toxic effects of ammonium on these marine plants because these algae remove the ammonium from water more quickly than marine angiosperms do.

This verification is really important, not only to understand the complexity of how this ecosystem works, which is more resistant depending on the existing functional biodiversity, but also, to rise a clear interest among environmental managers, in order to develop an accurate management of seagrass meadows.

The article published in the Plos One magazine, entitled "Interaction between ammonium toxicity and green tide development over seagrass meadows. A laboratory study," has been developed thanks to the existing cooperation between the University of Cadiz and the Roskilde University (Denmark), and whose authors are the doctorate student Francisco Moreno Marin, and Professors Fernando G. Brun, Juan J. Vergara and Jose L.ucas Péerez Lloréens at the UCA, as well as Professor Morten F. Pedersen from Roskilde University (Denmark).

It is interesting to remark that Francisco Moreno has a degree in Environmental Sciences by the UCA and, nowadays, he is a student in the Doctorate Programme of Sea Sciences and Technologies at the International Doctoral School in Marine Studies, EIDEMAR, attached to the International Campus of Excellence of the Sea (CEI.Mar). This young researcher is finishing his doctoral thesis carried out in cooperation with the University of Cadiz and the Roskilde University (Denmark) under the supervision of Professors Fernando G. Brun (UCA) and Morten F. Pedersen (RUC, Denmark), thanks to a bilateral cooperation agreement. This has made possible for the EDEA research group to hire him for two years with funding from the Sea-Live Project of the RDI National Plan and for the Roskilde University in Denmark to hire him, at present, while terminating his doctoral studies. Francisco Moreno will defend his thesis in Denmark as well as in Spain according to each country´s regulations, obtaining a double doctor PhD degree. These type of agreements strengthen internationalization of the UCA education activity in the framework of the International Campus of Excellence of the SeaCEI.Mar.

Moreover, this is not the only article published by this research group in this journal. In 2014, the scientists published a work on the interaction between the complexity of marine angiosperms seagrass meadows and hydrodynamics in modifying food availability for filter feeder organisms, such as clams, which live inhabit in these ecosystems. This work was part of the Doctoral Thesis of researcher Vanessa Gonzaález Ortiz and it was developed in cooperation with Professor Tjeerd J. Bouma from the Yerseke Institute of Sea Research (the Netherlands).