Rare benthic marine algae species discovered from the deep-water habitats of Bonaire

From Plant Press, Vol. 23, No. 1, January 2020.

David Ballantine, Barrett Brooks, and Gabe Johnson of the Botany Department collaborated on a recent publication in which two rarely reported and one newly described species of benthic marine algae were reported from deep-water habitats in Bonaire, representing the first Caribbean reports of each. The study was published in Botanica Marina (62: 587-593; 2019).

Archestenogramma profundum is previously known only from its type collection in Bermuda, and the rarely reported Halymenia integra is known originally from its type locality at Cabo Frio, Brazil. The newly described Verdigellas discoidea represents the fourth species in a rarely encountered genus first described in 1994 by James Norris and David Ballantine. Verdigellas species have an extremely simple morphology in which small spherical cells are embedded within a gelatinous matrix. Like the other members of their order, Palmophyllales, they survive today almost exclusively in deep water.

Benthic marine algae reported for the first time in the Caribbean (from left): Verdigellas discoidea, Archestenogramma profundum, and Halymenia integra. (photos by Barry Brown)

The mesophotic realm, loosely defined as marine low light environments at depths from 30 - 150 m, has in recent years proven to be a rich source of undiscovered biodiversity, in terms of both fauna and flora. Given the technological difficulties and expense involved with working at such depths, only a small percent of such habitats has been examined and only a handful of deep-water programs have existed in the Caribbean region.

Johnson did the genetic barcoding for the newly described species. His findings supported the new species designation for the collection and underscored the need for more molecular resources to be developed in order to understand the evolution of these early-branching lineages of green plants.

These collections were made in 2017 while Brooks participated in a NMNH Deep Reef Observation Project (DROP) expedition, using the deep research submersible Curasub (http://www.substation-curacao.com).