Climate change and sea grass
Climate change refers to the significant and lasting alteration of the Earth’s global climate. This variation may be due to natural causes (volcanic eruptions, ocean circulation, solar activity or variations in the Earth’s orbit) and/or as a consequence of human activities (burning of fossil fuels, deforestation, overconsumption, food production, among others).
Do you know the effects of climate change on the marine environment?
Climate change can cause different effects, such as:
- Rising temperatures and sea level.
- Melting of the poles.
- Acidification of the oceans.
- More frequent and devastating extreme weather events.
- Alteration of marine currents.
- Alterations in the metabolism and lifestyle of marine organisms.
How can we act to cope with these changes?
At present, there are different lines of action to address climate change, but they are generally divided into two:
- Mitigation measures: aimed at combating the cause, those activities that have a negative influence on climate change and minimizing possible impacts. For example, some of the actions we could take at a personal level are the use of public transport and reducing the use of plastics.
- Adaptation measures: these would help to reduce the potential actual or expected negative effects of climate change.
Did you know that sea grass does an important role against climate change?
Sea grass (Posidonia oceanica) is a marine plant endemic to the Mediterranean Sea. Among many of the benefits of its presence in the marine ecosystem, its ability to naturally prevent coastal erosion. In other words, its presence mitigates part of the adverse effects that climate change can cause. On the one hand, the roots and rhizomes advandage the fixation and retention of sediments, while on the other hand, the leaves attenuate the speed with which waves reach the coast.
In addition, the accumulations of sea grass remains that reach the beaches due to the action of the waves and after sea storms, play a very important role in the conservation of the beaches, mainly by cushioning the impact of the waves on the shore, controlling erosion and the loss of sand. These accumulations of sea grass remains are called arribazones, and their management is essential as a measure of adaptation to climate change.
The removal of arribazones… how is it managed?
At present, at the national level, there are no specific regulations on the removal of sea turtles from beaches. In the catalonian case, the Order of July 31, 1991, for the regulation of marine phanerogamos herbazales, prohibits the destruction, sale, purchase and use of these species.
For the correct management of upwelling, different strategies can be applied, such as those described in the GESTARR project:
- Keeping the upwelling in their place of origin
This is obviously the best from an ecological point of view and consists of keeping the upwelling in the place where they are naturally deposited. This should be imperative on beaches subject to erosion processes where the presence of plant debris helps to retain sediments.
- Temporary accumulation of arribazones
Arribazones can accumulate on or off the beach during the bathing season, returning them to their place of origin at the end of the season. Although they lose their protective function during the summer, they would be present during the rest of the year when the probability of storms is greater.
- Alternative use
The arribazones are extracted from the beaches, giving them a use outside of the beaches. Currently, of the different uses given to these plant remains, the most important are the recovery of green areas, compost formation, landfill sealing or dune stabilizers. There are also lines of research open for new industrial applications.
- Transfer the arribazones to landfills.
Extracting the sea grass remains from the beach and depositing them in landfills. This is the least sustainable action, however, it has been used for many years and has meant the loss of the ecological function of the sea grass remains and millions of cubic meters of sand.
Our expert’s opinion
As mentioned above, sea grass has a fundamental ecological function for the health of the Mediterranean. The effective management of the sea grass remains that are deposited on the beaches is essential as a measure of adaptation to climate change.
It is necessary to normalize the presence of the arribazones and develop awareness campaigns so that visitors are aware of the importance of these plant remains and change their views on the matter.
The permanent removal of sea grass remains, for alternative use or for transfer to landfills, is not considered a good management action as it permanently eliminates the function of these remains as a climate change adaptation measure. In addition, the removal of the beach tops entails another problem, the elimination of large volumes of sand. For this reason, these actions should be avoided so as not to leave the beaches in a highly vulnerable situation.