Four New Deep-Water Algae Discovered in Hawai’i

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Four new species of deep-water algae from Hawai’i have been announced by scientists working with NOAA’s Office of National Marine Sanctuaries. The new species of marine algae were collected at depths of 200 to 400 feet, which are sea depths not generally known for marine algae.

The study was recently published in the Journal of Phycology, titled “New Ulvaceae (Ulvophyceae, Chlorophyta) from mesophotic ecosystems across the Hawaiian Archipelago.”

“I was astounded at the abundance and size of these algae, which resembled something you would see in a shallow-water lagoon, not at 400 feet,” said Dr. Heather Spalding, a postdoctoral researcher at the University of Hawaiʻi’s Department of Botany and lead author of the study.

For years, Dr. Spalding has collaborated with NOAA’s Office of National Marine Sanctuaries studying samples collected by NOAA divers working in Papahānaumokuākea Marine National Monument.

Along with her colleagues at UH and the University of Washington’s Friday Harbor Laboratories, Dr. Spalding has worked to conduct DNA analyses that showed the differences between the species found in Hawai’i’s shallow waters and the deep sea specimens, even though the two appear to look similar.

“If you picked up one of these algae on the beach, you couldn’t tell if it was from a nearby rock or washed up from the deep, the species look that similar,” said Dr. Spalding.

In appearance, the newly discovered species look similar to limu pālahalaha (Ulva lactuca), or sea lettuce.

Scientists consulted with the Native Hawaiian community to develop meaningful names for the new species to honor the great importance they have in Hawaiian culture.

One species was named Ulva iliohaha, which refers to the foraging behavior of ʻīlioholoikauaua, the endangered Hawaiian monk seal, one of Papahānaumokuākea’s best-known residents.

Surveys between 2013 and 2015 in the Papahānaumokuākea Marine National Monument were used to gather the samples using advanced SCUBA diving technologies, along with past NOAA expeditions from 2006 to 2014, through the Main Hawaiian Islands using submersibles operated by the Hawai’i Undersea Research Laboratory.

Further findings of new species are anticipated as samples collected by NOAA divers on future expeditions to the monument are studied.

“These findings redefine our understanding of algal distributions in Hawaiʻi, and hint at the great number of other new species that are likely to be discovered in the future from these amazing deep-water reefs,” said Daniel Wagner, Papahānaumokuākea research specialist with NOAA’s Office of National Marine Sanctuaries.

Marine algae, also known as limu, are an important part of Hawaiian culture, used in foods, ceremonies, and as adornments in traditional hula.

NOAA courtesy image.

NOAA courtesy image.

NOAA courtesy image.

NOAA courtesy image.

NOAA courtesy image.

NOAA courtesy image.