Researchers from the University of Hawaiʻi at Mānoa have made a significant discovery regarding the invasive red alga, Chondria tumulosa, which was first detected smothering coral reefs in the Papahānaumokuākea Marine National Monument (PMNM). For the first time, the alga has been identified outside of its initial location, at Majuro Atoll in the Republic of the Marshall Islands, over 2,000 miles away.
This finding raises urgent concerns about the potential spread of C. tumulosa, which has been known to form dense mats that suffocate coral reefs and displace native flora and fauna. Patrick Nichols, a graduate student involved in the research, emphasized the need for broader monitoring efforts across the Pacific as the alga may be more widespread than previously thought.
Initially identified in PMNM in 2016 and named in 2020, C. tumulosa has posed significant challenges to coral reef conservation. The detection in Majuro was made possible through environmental DNA (eDNA) analysis, a method that allows researchers to identify species from water samples without extensive in-water surveys.
Following the eDNA analysis, a team from UH traveled to Majuro in November 2024 to confirm the presence of the alga through microscopy and genetic sampling. Although C. tumulosa was found in lower abundance in Majuro compared to PMNM, its presence raises questions about its ecological status in the region.
Researchers plan to extend their surveys beyond the Marshall Islands to understand the alga's distribution and ecological role better. This collaboration highlights the importance of new technologies in addressing the challenges posed by invasive species in fragile marine ecosystems.