Climate Detectives Projects 2019-2020

Project topic: Oceans

Project title: The decrease of Posidonia meadows in Lesbos island due to climate change.

Team: The Posidonians

2019-2020   Primary School of Keramia Lesbos   Mytilene   Greece   8 Student’s age: 10-11


Summary of the project

Our project has to do with the decrease of Posidonia Oceanica meadows in Lesbos island. The underwater meadows of Neptune Grass Posidonia Oceanica, offer excellent opportunities for implementing Environmental Education activities due to the combination of three factors: 1) They have high conservation value and are of priority for protection in EU level 2) They are widely distributed along the Mediterranean coasts and most students are familiar and 3)They leave numerous signs along the coasts in the form of thick layers of dead leaves, rhizomes, uprooted plants. More specific we started by decide our team name and logo and discussing about marine ecosystems, species that live in, professions dealing with it and we focused on Posidonia Oceanica. Then the plan was to follow the scientific method as experts do, where scientists collect their data from the underwater field and then compare them with satellite images using appropriate tools and applications. Students had the chance to see scuba diving equipment and from what it consists of. Next -as we couldn’t go scuba diving to collect our data- we created our bottom of the sea to simulate collecting data. We discussed about satellites and their functions and we focused on two satellite images taken from a selected place on island in different years to compare them. Then students used some of the tools that scientists work to see how they work and combine data from underwater with satellite images. Finally we discussed about reasons that cause the decrease, searched for data from previous heat waves and possible solutions that can reverse the situation.

Main results

From what we studied and what we discussed with our scientific partner there are many factors that can lead in decrease of Posidonia Oceanica meadows. Students decided that free anchoring, fishing methods such as trawlers or using sliding tools, water pollution and the increase of water temperature are factors that play important role in the decrease of Posidonia meadows. And if we are sure about illegal anchoring or fish trawlers however there has to be a more intense investigation from back in time till now for being sure that factors such Sea Surface Temperature play that important role in Posidonia extinction. What is more there many other factors that must count so as to reach a safe and clear conclusion about all factors that are guilty. (f.i morphological parameters) Finally, from this work we concluded that the use of satellite imagery is a method that allows the collection of high-precision data and also the final goal of the project was to ensure the long-term protection of seagrasses as well as to reduce the main threats to this habitat type: invasive alien species, trawlers and free anchoring.

Actions to help lessen the problem

Trying to find possible actions to help lessen the problem, students suggested • Installation of environmentally friendly anchorages and strict zoning for anchoring. In this way the integrity of sensitive habitats in areas where it grows maritime tourism activity and also offers places safe mooring of ships. • In order to ensure the integrity of the meadows, it is important the prohibition of fishing with sliding tools (gray – gray) in areas where they exist. The ban on fishing with slides also protects local fish stocks, mainly pelagic, which are valuable to populations of seabirds. As we have already mentioned, the meadows operate as kindergartens for small fish of all kinds. In case that fishing gear with sliding tools continue to fish in such areas, the result is to catch all the sizes of fish, where it is usually smaller than allowed, resulting in emptying offspring area, the inability to trade small sizes due to legislation with the end result of the rejection of the dead now fish in the sea. • “Reforestation” of the bottom with parts of the plants which come out of the sea after severe weather conditions using biodegradable plant materials in a graft and placing it underwater. It is remarkable the ideas and opinions that students express during discussion not only about these possible taking actions but also the whole project.

Project video


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