My name is Alexandra Gimblett, and I am currently studying Marine and Freshwater Biology BSc at Aberystwyth University. While on my year in industry I chose to spend six months with Archipelagos Institute of Marine Conservation collecting samples of Posidonia oceanica and Halophila stipulacea seagrass in order to later perform DNA analysis at my university.

I collected 20 samples of P. oceanica from 7 sites around Lipsi and 4 sites around Samos and 40 samples of H. stipulacea from Lipsi and 5 samples of H. stipulacea from Samos. In Lipsi I carried out the sampling while freediving as the deepest samples were at 7 metres. However, in Samos I scuba dived when collecting samples as I had to reach to 15 metres in depth. At each sampling location I noted down the depth, time, epiphyte coverage, and blade length of each sample and whether it was from the edge or middle of a patch as well as recorded the water visibility, salinity, and water temperature.

collecting samples of Posidonia oceanica and Halophila stipulacea seagrass

When I analyse these samples, I will use microsatellite markers for genotyping, and I will compare samples from Lipsi and Samos. There are differences in the levels of human disturbance and pressure of each site around Lipsi and therefore I will compare these sites to determine if disturbance can impact seagrass at a genetic level. As I have not carried out any genetic analysis, I do not have any results yet however, previous studies in Italy suggests that human disturbance has a negative impact on genetic diversity which could be detrimental for P. oceanica as it has already been significantly reduced due to human disturbance and anthropogenic impacts.

If genetic diversity decreases or is lower in areas of disturbance the species could be more fragile to future disturbance as the species is unable to resist changing environments and is therefore less resilient. It is important to determine the impacts that human disturbance has at a genetic level to be able to protect areas where P. oceanica so it can continue to flourish and provide vital ecosystem services.

Results for this project will be available in April 2023.

Alexandra Gimblett, BSc Marine and Freshwater Biology, Aberystwyth University, Wales United Kingdom