''Chondria tumulosa'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

red algae Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...

in the family Rhodomelacae. It was first discovered in 2016, growing in small patches in the

Pearl and Hermes Atoll The Pearl and Hermes Atoll ( haw, Holoikauaua), also known as Pearl and Hermes Reef, is part of the Northwestern Hawaiian Islands, a group of small islands and atolls that form the farthest northwest portion of the Hawaiian island chain. The ...

in the

Northwestern Hawaiian Islands The Northwestern Hawaiian Islands or Leeward Hawaiian Islands are a series of islands and atolls in the Hawaiian island chain located northwest (in some cases, far to the northwest) of the islands of Kauai and Niihau. Politically, they are all p ...

. By 2019, the species had spread to cover several thousand square meters, smothering and killing vast swathes of the atoll's

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Co ...

s. ''C. tumulosa'' is unlike any other species in its

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

, having a

tumbleweed A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants. It is a diaspore that, once mature and dry, detaches from its root or stem and rolls due to the force of the wind. In most such species, the tumble ...

-like growth form that allows fragments to break off and spread, allowing it to colonize new areas. The true origin of ''C. tumulosa'' in the region remains unknown; it displays many characteristics of an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

and is not closely related to any other Hawaiian '' Chondria'', but it would have been relatively difficult to colonize such a remote area. It has also been suggested that it is a native species that suddenly spread due to changes in the ecosystem. Control and mitigation strategies will have to be made to prevent the species' spread.

References

Northwestern Hawaiian Islands Rhodomelaceae Pearl and Hermes Atoll {{rhodophyta-stub