Biology subjects

Gress, E.

Publications and source records attributed to Gress, E..

2 recordsLinked to original sources

bioRxiv2021

Investigating densities of Symbiodiniaceae in two species of Antipatharians (black corals) from Madagascar

Here, we report the first methodological approach to investigate the presence and estimate the density of Symbiodiniaceae cells in corals of the order Antipatharia subclass Hexacorallia, known as black corals. Antipatharians are understudied ecosystem engineers of shallow (<30 m depth), mesophotic (30-150 m) and deep-sea (>200 m) reefs. They provide habitat to a vast number of marine fauna, enhancing and supporting coral reefs biodiversity globally. Nonetheless, little biological and ecological information exists on antipatharians, including the extent at which global change disturbances are threatening these corals. The assumption that they were exempted from threats related to climate change was challenged by findings of high density of dinoflagellates within three antipatharian colonies. Further methodical studies were necessary to investigate the regularity of these findings. An integrated design combining microscopy and molecular techniques was used to investigate the presence and estimate density of Symbiodiniaceae cells within two antipatharians species -Cupressopathes abies and Stichopathes maldivensis -from shallow and mesophotic reefs of SW Madagascar. Symbiodiniaceae-like cells were found within the two species from both shallow and mesophotic reefs, although the overall cell density was very low (0-4 cell mm-3). These findings suggest that high abundance of Symbiodiniaceae is not characteristic of antipatharians, which has relevant implications considering disruptions associated to climate change affecting other corals. However, the high densities of dinoflagellates found in antipatharian colonies exposed to higher light irradiance in other studies should be further examined.

molecular biology↗

bioRxiv2017

Mesophotic Coral Ecosystems Inside and Outside a Caribbean Marine Protected Area

Recent widespread shallow coral reef loss has led to calls for more holistic approaches to coral reef management, requiring inclusion of all ecosystems interacting with coral reefs in management plans. Yet almost all current reef management is biased towards shallow reefs, and overlooks that many reef species can also be found on mesophotic coral ecosystems (MCEs; reefs 30 -150 m). This study presents the first detailed quantitative characterisation of MCEs off Cozumel, in the Mexican Caribbean and provides insights into their general state. We investigate whether MCEs within the marine park have similar ecological communities to mesophotic reefs outside protection, despite widely recognised shallow reef impacts outside the protected area. Results show some taxon specific differences in MCE benthic communities between sites within the protected area and areas outside; although overall communities are similar. Regardless of protection and location, and in contrast to shallow reefs, all observed Cozumel MCEs were continuous reefs dominated by calcareous macroalgae, sponges, octocorals, and black corals. Hard corals were present on MCEs, but at low abundance. We found that 42.5 % of fish species recorded on Cozumel could be found on both shallow reefs and MCEs, including many commercially-important fish species. This suggest that MCEs may play a role in supporting fish populations. However, regardless of protection status and depth we found that large-body fishes (>500 mm) were nearly absent at all studied sites. MCEs should be incorporated into the existing shallow-reef focused management plan in Cozumel, with well informed and implemented fisheries and harvesting regulations.

ecology↗