A newly-identified, fast-growing species of algae poses a major threat to coral reefs and the ocean ecosystem. It was previously discovered in Papah膩naumoku膩kea Marine National Monument by a team of researchers from the University of Hawaiʻi, Western Australian Herbarium, College of Charleston and National Oceanic and Atmospheric Administration (NOAA).

Newly-named Chondria tumulosa by 东精影业 researchers, the alga has no known origin and has been observed smothering entire reefs and the corals, native algae and other organisms that live in one of the northern atolls. It also has a “tumbleweed-like” growth and appears to easily detach and spread.

“I think this is a warning of the kinds of changes that are to come for the northwestern Hawaiian Islands,” said 东精影业 惭腻苍辞补 Interim Associate Dean and Professor Alison Sherwood, the lead researcher on the project. “We have, not until now, seen a major issue like this where we have a nuisance species that鈥檚 come in and made such profound changes over a short period of time to the reefs.”

It was not widespread when first detected by divers in 2016 but a 2019 visit to the same area revealed that it is now covering up to several thousand square meters at the Pearl and Hermes Atoll.

“Until we understand whether it is native or introduced, and until we better understand what is driving this outbreak, it is critically important that research divers and research ships do not inadvertently transport this species to other islands,” said Randall Kosaki, NOAA research coordinator at Papah膩naumoku膩kea Marine National Monument. “Thus, all of our dive gear was soaked in bleach, and all of our dive boats were sprayed down with bleach prior to returning to Honolulu.”

The findings were featured in a PLOS ONE article, “.”

‘Nuisance’ not ‘invasive’

Although Chondria tumulosa displays invasive characteristics, researchers are calling it a “nuisance alga” because they have not identified it as being introduced from another region.

“The main Hawaiian Islands are impacted by several well-known invasive seaweeds, but reports of nuisance algae in Papah膩naumoku膩kea Marine National Monument are far fewer, and none have been present at the level of abundance seen in this new alga,” Sherwood said.

Next steps

Researchers will conduct mapping and molecular analyses, and will develop mitigation strategies to assist in the development of appropriate management actions.

“This is a highly destructive seaweed with the potential to overgrow entire reefs,” College of Charleston Assistant Professor Heather Spalding said. “We need to figure out where it鈥檚 currently found, and what we can do to manage it. This type of research needs trained divers in the water as quickly as possible. The sooner we can get back to Papah膩naumoku膩kea Marine National Monument, the better.”

—By Marc Arakaki

A new study on Hawaiian limu reveals that some are only found in deep, dimly lit waters. Limu, or algae, are photosynthetic protists with a myriad of uses, from food and food additives, to cosmetics, paints, toothpaste and biofuels.

A team of researchers from the , and the were awarded $792,021 by the National Science Foundation (NSF) to describe the new species of limu, or marine algae, from Hawaiʻi鈥檚 deep waters. They anticipate the description of more than 60 new species of limu, and many new records for the Hawaiian Archipelago.

“This is one of the most extensive studies of mesophotic (existing in low light) algae to date,” said , a 东精影业 惭腻苍辞补 professor in the and principal investigator of the grant. “We have nearly 2,000 specimens of limu collected from 100 to more than 600 feet deep across the entire Hawaiian Archipelago. This will redefine our understanding of limu diversity in Hawaiʻi and will aid understanding of floras across the entire Indo–Pacific.“

New deep frontier for coral reef research

These deep limu specimens were collected from mesophotic coral ecosystems, or coral reefs at depths of 30– to 150–plus meters (100– to 500–plus feet). These areas are among the most poorly explored of all marine ecosystems on Earth. Deeper than conventional scuba divers can safely venture and shallower than most submersible–based exploration, these reefs represent a new frontier for coral–reef research.

The limu collections are from the entire 2,590–kilometer (1,600–mile) extent of the Hawaiian Archipelago, from Kure Atoll to the Big Island of Hawaiʻi. Technical divers using closed–circuit rebreathers, open–circuit scuba and the research submersibles Pisces IV and V were used to collect the algae. The collections were supported by NOAA鈥檚 National Centers for Coastal Ocean Science, Papah膩naumoku膩kea Marine National Monument, Coral Reef Conservation Program, Office of Ocean Exploration and Research and the . With the support of the National Science Foundation, the researchers will use a combination of DNA techniques and anatomical studies to describe these new species.

“The limu form beds and meadows in this deep, blue water, and some appear to form habitat for fish and invertebrates,” says , a co–principal investigator on the NSF grant. “These new species aren鈥檛 just tiny fuzz on the reef—they鈥檙e huge blades of brightly–colored red, brown and green limu. It鈥檚 like a garden down there, with new species poking up around every reef. We鈥檙e just on the tip of the iceberg in terms of understanding algal diversity in the mesophotic.“

The project will involve a team of undergraduate and graduate students, and postdoctoral fellows. Mary Ade, a student who is working in the Sherwood Lab this summer through the project, is one of the first to join the project. Her summer research project will wrap up with the description of several new species of brown algae in the genus Dictyota.

—By Tony Hall

Land-use practices on tropical oceanic islands can have large impacts on reef ecosystems, even in the absence of rivers and streams. Land-based pollutants, such as fertilizers and chemicals in wastewater, infiltrate into the groundwaters beneath land and eventually exit into nearshore ecosystems as submarine groundwater discharge (SGD)—seeping into the coastal zone beneath the ocean’s surface. In a , University of Hawaiʻi at Mānoa scientists used a combination of field experiments and chemical analysis of water and algae to show that the quality of coastal groundwater plays a major role in determining the health of nearshore ecosystems in Hawaiʻi.

Various sources of pollution, such as agriculture or sewage treatment facilities, have identifiable chemical signatures, particularly the isotopes of nitrogen in the nutrients they contain. This study assessed groundwater quality, coastal water quality and reef health across six different bays on Maui with various potential sources of pollution. By comparing the nitrogen isotope signature of algae tissues and potential pollution, the research group traced nutrients in the algae back to their land-based sources.

Impact of wastewater

This study is the first to show the extent of the impact of wastewater injection wells at Kahului Wastewater Reclamation Facility, Maui’s highest-volume sewage treatment plant, on Kahului Bay. In addition to relatively high nutrient levels in marine surface waters in Kahului Bay, shallow areas were almost entirely dominated by a thick fleshy mat of colonial zoanthids, a phenomenon not reported anywhere else in the state. to this work, led by James Bishop at the 东精影业 Mānoa , found that water collected from beach sands, which represents coastal groundwater, next to the Kahului Wastewater Reclamation Facility contained up to 75 percent treated wastewater—highlighting the impact of wastewater in this area.

“Our timely study builds on previous research from 东精影业 scientists and recent federal court rulings that show that treated wastewater is illegally discharged to the ocean from injection wells at the Lahaina Wastewater Reclamation facility via SGD to Kahekili Beach Park on West Maui,” said Daniel Amato, lead author and recent graduate of the 东精影业 Mānoa College of Natural Sciences. “This is not an isolated or unique occurrence.”

Effects of agriculture

Reefs adjacent to large areas of sugarcane agriculture were the most impacted of all the sites in this study. At Kūʻau and Māʻalaea Bays, coastal waters contained nearly 100 times more nitrogen than less impacted locations due to fertilizer-enriched SGD. These high levels of nutrients were reflected in the tissues of common macroalgae and measures of reef community structure. A few species of macroalgae dominated intertidal and subtidal surfaces at Kūʻau and Māʻalaea Bays. In contrast, areas where coastal groundwater nutrient levels were relatively low, researchers observed much greater diversity and corals were generally present, indicating a healthier, potentially more robust, ecosystem.

This study suggests that contaminated groundwater may present a chronic risk to nearshore marine ecosystems throughout the main Hawaiian Islands. These results are especially significant for coastal managers and lawmakers who will influence the future of land-use policy in Hawaiʻi. Of particular future interest is the possible benefit gained in health of our reefs by the reduction in Maui’s sugarcane production. Reducing groundwater pollution could result in future increases in reef health and decreases in the occurrence of nuisance algal blooms for impacted areas.

“The long-term goal of this research group is to bridge the disciplines of hydrology, geochemistry and marine biology to help answer pressing questions regarding the source and impact of nutrient pollution in Hawaiian coastal waters,” said , and , the collaborating principal investigators and co-authors of the project.

These studies were funded by the University of Hawaiʻi Sea Grant College Program and a U.S. Environmental Protection Agency STAR Graduate Fellowship.

—By Marcie Grabowski

In honor of what would have been Professor Emerita Isabella Abbott’s 97th birthday, University of Hawaiʻi at Mānoa’s Celia Smith, professor of , led an invasive algae clean up at the on June 20. This year’s clean up gathered about 45 volunteers including 东精影业 students and community members to learn about invasive seaweeds and remove them from the reef in Waikīkī.

“Our efforts to honor Dr. Abbott are guided by the need to return balance to reefs for the resilience and sustainability we need, as our oceans change profoundly,” said Smith.

Several species of alien algae have become established on Hawaiʻi’s reefs, and have contributed towards the decline of some reef areas. One such area is the reef fronting the Waikīkī Aquarium, and efforts have been underway since 2002 to remove these alien species. Driven by Smith and her botany students, this aquarium collaboration removes the alien algae by hand while taking care to return any native algae to the ocean. The alien algae are weighed, to assess both the scale of the challenge and the effectiveness of the removal efforts, and transported to . There the algae are added to the zoo’s compost pile, which is used to fertilize the plants on the zoo grounds and available for public use.

For the last six years, the month of June was selected for algae education and community service in honor of the late Isabella Abbott, who passed away in 2010. The “First Lady of Limu,” was a world-renowned algae taxonomist and ethnobotony professor emeritus at 东精影业 Mānoa.

• Related: Read more about in Mālamalama, October 21, 2010