This blog is written by Sian Davies-Vollum. Sian is Head of the School of the Built and Natural Environment at the University of Derby, where she studies coastlines, how to look after them and the lives that they support. She loves to be outdoors and has always been curious about how landscapes are formed. Sian is part of our #AskAGeo network, and you can get in touch with Sian on Twitter @SianDV.
I consider myself pretty lucky: I am a geoscientist who works at the beach. Not just any old beach, but beaches in warm tropical places with palm trees and turtle nesting sites! It sounds like a dream job – and it is, I love it – but it is an important job, too.
My work is about finding ways to take care of our coastlines and support the communities who live close to them. Recently I have been working with scientists in Ghana, Benin and Nigeria to find out about lagoons in and the people who live around them in these countries in West Africa. Lagoons are a particularly important environment at coastlines around the world. I think they are fascinating, and very beautiful. In fact, I think lagoons are lovely! Sadly though, our lovely lagoons are under threat. But first, what is a lagoon and why do they matter? Let me tell you a bit about them.
Lagoons – a special kind of lake
You can find lagoons at coastlines that are quite flat where the land isn’t much higher than the level of the sea. They are big, shallow lakes that sit behind a narrow strip of beach. The beach acts as a kind of dam that separates the lagoon from the sea. However, because beach barriers are made of sand, they are quite fragile and are easily worn away by waves or by flooding from the lagoon. It is easy for floods or waves to make a gap in the beach barrier and the gap connects the lagoon to the sea. This means that sometimes lagoons are filled with salty water like the sea but at other times they are filled with fresh water, just like any other lake. This on/off connection to the sea is all part of their natural cycle and it makes lagoons home to many plants, fishes, birds and animals.
In tropical countries, such as Ghana in West Africa, people who live around lagoons are really connected to their local surroundings and rely on what the natural environment provides. They often fish for food and for their job, and use wood collected locally to cook on and build homes.
The impact of the Climate Crisis
Lagoons are very sensitive to changes to rain and storms, and climate change is having a big effect on them. We have studied the record of weather at the Muni lagoon in Ghana and talked to people who live around it to ask them about changes they have seen in the weather. We found that the pattern of rain is changing and that this has interrupted the natural cycle of the Muni lagoon. The lagoon floods when not expected and the beach barrier is being worn away in some places. The changes to weather, the flooding and the wearing away of the barrier are all associated with climate change and they cause problems for the people who live around Muni lagoon, homes are at risk from flooding and fish catches are not as big as they used to be.
Protecting lagoons for the future
What can we do to help the Muni lagoon and the people it supports? If we understand lagoons better, we can put in place ways to protect them. For example, there are plants called mangroves that are a lagoon’s natural protection from storms. They help to trap the lagoon barrier’s sand and stop it from being worn away. If we can make sure a lagoon has healthy mangroves, we know we are helping to protect the lagoon for all the fish, animals, birds and people who live around it.
I am part of a group of scientists from West Africa (in Ghana, Benin and Nigeria) and the UK who have set up a group called the Resilient Lagoon Network. We are working together to find out more about the science of lagoons and what we can do to make sure that they have a good future. We also want to let everyone know how important lagoons are, so we made a website that has lots more information about lagoons.
I am hoping to go back to Muni lagoon in Ghana soon. I am excited to explore how the lagoon has changed since I last visited over 2 years ago, and to see the mangroves that have been planted there. Most of all, I hope to see evidence of healthier, happier lagoon.
The team at the heart of the Resilient Lagoon Network specialise in fields such as geoscience, ecology, coastal engineering and management, development studies, public health, and social and economic geography. They represent institutions including the Universities of Derby, Portsmouth, Oxford and Ghana-Legon; the University of Education, Winneba; the Ghana Forestry Commission; the Institut de Recherches Halieutiques et Océanologiques, Bénin; Yaba College of Technology, Lagos; and the University of Lagos. Want to know more about their work? Check out these scientific articles!