Meet SLU's own marine detective Maria Eggertsen

Hi Maria, tell us more about algae and why they are important?

Algae are important primary producers in the shallow ecosystems and are incredibly productive. They are also the basis of the food web in many tropical seascapes by providing food and habitat for a large number of organisms such as fish, crustaceans and snails.

What role does algae play in Hawai'i?

Traditionally, algae have played an important cultural role in Hawai'i. Among other things, they have been used as ingredients in cooking and as flavor enhancers. Algae has also been a great source of vitamins and has been used as some traditional medicines. Unfortunately, quite extensive environmental degradation, such as logging, military, agriculture, new infrastructure and overfishing, has taken a toll on the coastal waters, especially on the island of O'ahu, and many of the algae that were abundant just a generation ago have now disappeared or declined significantly.

How do invasive algae affect native algae species?

Invasive algae species simply outcompete the native species. When one species becomes very dominant, it displaces all others and then biodiversity is threatened. Some other species may even disappear completely at the local level, and then important habitats and food for the coral reefs' other inhabitants, such as fish, also disappear.

How did the invasive algae get to Hawai'i?

Some of the invasive algae species have been introduced to be cultivated and others have come as stowaways on ships and then spread around O'ahu and the other islands belonging to Hawai'i. The five most successful ones are all on O'ahu where I was based.

A few years ago, an aggressive red algae was discovered in Papahanaumokuakea National Park in northwestern Hawaii. Tell us more about this specific algae?

It was discovered that the algae had begun to dominate in some places on the Pearl and Hermes atoll (Manawai). It grows very densely and forms like mats on coral reefs. This means that it first suffocates and then quite effectively kills the corals and native algae that it grows over. The algae turned out to be a new species, so far unknown to researchers, and no one knows if it actually belongs to Hawaii'i, or if it was introduced from somewhere else. Alison Sherwood, who is the head of my lab, described it in 2020 and named it Chondria tumulosa.

Describe what your role is in this research project?

I'm simply trying to figure out what it is that makes certain algae so harmful to their "new" ecosystems, and whether it is possible to draw any general conclusions based on their functional properties, for example by high-risk marking certain species that you should be extra careful with. In our research group, we are also working with dispersal models and we will investigate dispersal patterns of Chondria tumulosa in particular and how and where it would emerge first and establish itself should it spread to Hawaii's main islands.

What is the most fun part of your job?

The best thing about my job is of course that it is exciting and interesting, and a job where I can actually make a difference for our oceans. I love that I get to be a bit like an explorer or detective when I'm researching, and it's a very creative job, it's fun!

What do you hope to contribute to your research?

I hope to be able to contribute with some small piece of the puzzle on how we can preserve and manage our oceans together. Or maybe it's not really "our" oceans, we share them with all the other small and large inhabitants of the planet, and in this particular project we want to understand the mechanisms behind invasive algae and how we can avoid them becoming a problem.