Environmental factors that influence the distribution, size, and biotic relationships of the Christmas tree coral Antipathes dendrochristos in the Southern California Bight

Abstract

The Christmas tree coral Antipathes dendrochristos is a recently discovered black coral species that represents a habitat associated with numerous sensitive taxa in the Southern California Bight. We evaluated whether broad-scale oceanographic features influence coral density and size by selecting from among generalized additive models (for density) and generalized linear models (for size) that represented competing hypotheses. We constructed models to predict coral density and size using depth, seafloor slope, surface primary productivity, bottom currents, ocean temperature, salinity, and dissolved oxygen as candidate covariates. Specifically, we evaluated hypothesized links between pelagic production and benthic coral utilization and between bottom currents and larval coral dispersal. Our analysis revealed that high surface primary productivity in combination with depth and January currents are important predictors of Christmas tree coral density. Higher coral density coincided with greater chlorophyll persistence and optimal depths near 400 m. Surface productivity increasingly was associated with Christmas tree corals at shallower depths. Our results supported the hypothesis that ocean currents affect coral density via larval dispersal mechanisms. The selected coral size models responded to similar covariates, corroborating coral density results. Fish and invertebrate ordinations indicated that Christmas tree corals were widely distributed across environmental gradients and that Christmas tree corals cooccurred with several demersal fish and invertebrates. Several predicted coral hotspots remain unprotected from fishing, particularly in areas adjacent to highly populated portions of the Southern California Bight. These regions should be targeted by future studies to confirm the presence of Christmas tree coral communities and to evaluate their vulnerability.

Settlement, colonization, and succession patterns of gold coral Kulamanamana haumeaae in Hawaiian deep coral assemblages

“…Cross Seamount, the oldest site, with a mature gold coral population, is also the southernmost, sharing the same environment as sites with fewer corals (Westpac, Makapuu, Keahole). The role of environmental variables including current flow, particulate fluxes, and productivity (Huff et al 2013) in this depth range is not known. However, data loggers have monitored temperature in coral beds (5+ yr) across the archipelago and found it stable, varying between 8 and 11°C (Table 1) (Parrish & Roark 2009).…”

Deep-Sea Coral and Sponge Taxa Increase Demersal Fish Diversity and the Probability of Fish Presence

“…Models developed at finer scales are perhaps more useful to identify areas that could be protected from anthropogenic practices that may potentially damage these fragile DSCS taxa (Rengstorf et al, 2013;Gullage et al, 2017;Sundahl et al, 2020). For example, Huff et al (2013) found that the distribution of the Christmas tree coral in the SCB (Antipathes dendrochristos) was positively affected by a combination of persistently high surface productivity, water current velocity and direction near the seafloor, warmer temperature and shallow depth. Developing similar distribution maps for the other DSCS taxa associated with demersal fishes would be invaluable to fisheries managers seeking to protect these vulnerable fish habitats as they seek to rebuild overfished populations (Rosenberg et al, 2000).…”

“…This suggests that some of the other DSCS taxa that were near the top of the gradient forest analysis (e.g., Pennatulacea and Antipathes dendrochristos) also may have important habitat roles for other taxa that were not included in our logistic regression models. Habitats with persistent localized upwelling resulting from complex seafloor topography are areas where Antipathes dendrochristos are denser (Huff et al, 2013), and also may comprise the most important benthic habitats for other DSCS and fishes in the SCB.…”

Influence of Water Masses on the Biodiversity and Biogeography of Deep-Sea Benthic Ecosystems in the North Atlantic

“…For instance, L. pertusa reefs off Norway occur in waters as shallow as 50 m; with it being impossible to determine whether temperature (up to 10 • C) or salinity (down to 32) limit the upper bathymetrical distribution (Mortensen et al, 2001). Therefore, assertions on the potential controls of deepsea species distributions should be taken with caution (Huff et al, 2013). In addition, the relative importance of these factors varies between taxa and regions, but also with the spatial and temporal window of observation (Buhl-Mortensen et al, 2015;Radice et al, 2016).…”