UH Hilo marine botanist group launches Limu Ark, a culture collection of native algae

Posted on February 27, 2025February 28, 2025 by Staff

A dedicated group of scientists and their students has established over 40 species of native marine macroalgae in a culture collection named Limu Ark located at UH Hilo’s Pacific Aquaculture and Coastal Resources Center.

A hand holds a tube with the start of a piece of red seaweed. — A member of UH Hilo’s Limu Ark team holds a *Halymenia hawaiiana* or limu lepe o Hina in culture. (Courtesy photo)

By Susan Enright.

Aquaculture and marine scientists at the University of Hawaiʻi at Hilo are preserving native Hawaiian limu, one species at a time.

Karla McDermid pictured — Karla McDermid

With funding from the Pacific States Marine Fisheries Commission and the National Oceanic and Atmospheric Administration, Professor of Marine Science Karla McDermid and Professor of Aquaculture Maria Haws, along with three marine science students — Emma Poland, Lauren Runnels, and Abigail Nason — have succeeded in establishing over 40 species of native marine macroalgae in a culture collection named Limu Ark located at UH Hilo’s Pacific Aquaculture and Coastal Resources Center. Limu is the Hawaiian word for seaweed.

“There are over 600 species of limu in Hawaiʻi,” says McDermid, a marine botanist. “We need to preserve as many as we can for future research, education, and restoration.” She notes that simply having a facility to maintain small cultures of many limu species has inspired students to notice the diversity of species in the wild, which in turn adds to the number of species in culture.

To overcome the lack of culture methods for many species of Hawaiian seaweeds, the professors and their student team developed a small, containerized laboratory equipped to allow for control of environmental parameters such as light intensity, light wavelength, nutrient levels, and length of daylight in a 24-hour period. They are working to determine the precise combination of factors that induce growth, and hopefully reproduction, as well as the optimization of bioactive compounds for antioxidant, anti-inflammatory, anti-microbial, anti-nematode, and methane-reduction activity.

Woman in lab mixes water compound with large flasks. Microscopes and test tubes fill the table space. — Emma Poland, a UH Hilo marine science senior, prepares seawater media at the Limu Ark lab. (Courtesy photo)

Shelves of flasks and tubes with cultures. — Cultures growing in the Limu Ark (Courtesy photo)

A dark room with lit shelves filled with flasks. — Inside the Limu Ark. (Courtesy photo)

A shelf with six flasks containing cultures. — Three species in culture: *Ulva flexuosa, Ulva intestinalis, Amansia glomerata*. (Courtesy photo)

Shelves with flasks containing cultures. — Limu kohu on bottom shelf. (Courtesy photo)

“The abundance of many limu species in the Hawaiian Islands is changing and for some species, dwindling because of changes in water quality, nutrients, introduced species, higher sea temperatures, and even natural catastrophes,” says McDermid. “The lava inundation of Waiʻopae on Hawaiʻi Island wiped out a population of a beautiful little red seaweed, Laurencia galtsoffi, and I have not forgiven myself for not running down to the reef in the early days of the eruption to collect live specimens to culture before the lava covered them.”

The Limu Ark is a key component of a long-term research and outreach program designed to serve a wide range of stakeholders with interest in seaweed. The Limu Ark follows in the footsteps of the other culture collections of algae around the world, some with over 1,000 strains, including University of Texas at Austin, the University of the Philippines Marine Science Institute, the Norwegian Culture Collection of Algae, the Roscoff Culture Collection in France, and the Microgarden at University of California, Berkeley.

“I hope to partner with the state (government agencies) in the future to expand our capability to maintain cultures of seaweed,” says McDermid. “A 14th century proverb applies to UH Hilo’s Limu Ark: mighty oaks from little acorns grow.”