Study Aims to Understand Invasive Algae’s Success in New England Waters

By Zoe Cardon, MBL Senior Scientist

One of the world’s most successful marine invasive species -- the red alga Gracilaria vermiculophylla -- is expanding its range. While originally found in the Northwest Pacific Ocean, it has found its way around the world, including into the Atlantic, and is creeping north around the coasts of Cape Cod. As it moves along this path, it is edging into the range of its native, common relative, Gracilaria tikvahiae. Both species are currently found in Waquoit Bay in Falmouth, Mass.

This could mean bad news for some flora and fauna indigenous to the Cape Cod area. The invasive species can reduce eel grass bed productivity and can change the communities of invertebrates in coastal zones important for fisheries. The native and the invasive Gracilaria species share many characteristics given their common genetic background, but clearly there is something about the invasive species that makes it a superior competitor.

MBL Research Scientist Elena Lopez Peredo is working to understand what it is about the invasive that makes it robust in local waters. She has established experimental tanks at the Marine Resources Center (MRC) at MBL, and is studying locally gathered algae as well as representatives of the native and invasive species isolated by Charles Yarish at University of Connecticut.

Red algae naturally look red because they have pigments that strongly absorb green light and use it to grow. This means an important part of the MRC experimental set-up is providing a light spectrum to match the red, green, and blue wavelengths found in natural sunlight. Bright lights donated by Noribachi, Inc. have that full wavelength spectrum and are tailored to the needs of this experiment.

Several researchers have suggested that the invasive Gracilaria is better at preventing the establishment of colonies of disease-causing and/or fouling microscopic organisms on its surfaces. (This community is called the microbiome.) If that is true, how does the control system work? Depending on the kinds of organisms that get established on algal surfaces, microbiomes can actually be good for algal growth or they can be bad. Understanding what controls the formation of the microbiome and its activities is important for understanding the ecology of algae in natural coastal ecosystems and important for aquaculture of marine algae.

There could be some industrial applications to this research, as well. Gracilaria species are also used to produce agar, anti-fouling and antimicrobial compounds, so understanding how these red algae encourage the “right” microbiome and discourage the “wrong” organisms is potentially very useful.

Photo Caption: Elena Lopez Peredo and Zoe Cardon working in the MBL Marine Resources Center. Credit: Tom Kleindinst