Climate change winner in the deep sea? Predicting the impacts of climate change on the distribution of the glass sponge Vazella pourtalesii

Abstract

Shallow-water sponges are often cited as being 'climate change winners' due to their resiliency against climate change effects compared to other benthic taxa. However, little is known of the impacts of climate change on deep-water sponges. The deep-water glass sponge Vazella pourtalesii is distributed off eastern North America, forming dense sponge grounds with enhanced biodiversity on the Scotian Shelf off Nova Scotia, Canada. While the strong natural environmental variability that characterizes these sponge grounds suggests this species is resilient to a changing environment, its physiological limitations remain unknown, and the impact of more persistent anthropogenic climate change on its distribution has never been assessed. We used Random Forest and generalized additive models to project the distribution of V. pourtalesii in the northwest Atlantic using environmental conditions simulated under moderate and worst-case CO 2 emission scenarios. Under future (2046-2065) climate change, the suitable habitat of V. pourtalesii will increase up to 4 times its present-day size and shift into deeper waters and higher latitudes, particularly in its northern range where ocean warming will serve to improve the habitat surrounding this originally subtropical species. However, not all areas projected as suitable habitat in the future will realistically be populated, and the re duced likelihood of occurrence in its core habitat on the Scotian Shelf suggests that the existing Vazella sponge grounds may be negatively impacted. An ef fective monitoring programme will require tracking changes in the density and distribution of V. pourtalesii at the margins between core habitat and where losses and gains were projected. Species distribution models showed that the suitable habitat of the deep-water glass sponge Vazella pourtalesii will expand under climate change scenarios.

Life in the Fast Lane: Modeling the Fate of Glass Sponge Larvae in the Gulf Stream

“…Consequently V. pourtalesii is considered to be an ecosystem engineer. Beazley et al (2021) predicted that its distribution under future (2046)(2047)(2048)(2049)(2050)(2051)(2052)(2053)(2054)(2055)(2056)(2057)(2058)(2059)(2060)(2061)(2062)(2063)(2064)(2065) climate change could increase up to four times its presentday size and shift into deeper waters and higher latitudes, particularly in its northern range.…”

“…Effective conservation management of V. pourtalesii and other deep-sea sponges, including design of appropriate marine protected areas, can be supported by predictive species distribution models (Knudby et al, 2013;Beazley et al, 2018Beazley et al, , 2021Murillo et al, 2018). However, that approach can only provide some of the required information and often does not consider the ability of a species to disperse into isolated areas of predicted suitable habitat.…”

“…Knowledge of connectivity can enhance our comprehension of species distributions and is an important supplement to species distribution modeling, particularly if species responses under future climate projections are to be interpreted reliably (Holloway et al, 2016). Beazley et al (2021) did not model colonization potential for their habitat predictions for V. pourtalesii and so whether the species will be a "climate change winner" capable of colonizing the large expanse of seabed identified in their models, remains an open question.…”

“…In this study, we developed passive 3-D Lagrangian particle tracking models to investigate the physical connectivity of V. pourtalesii in the western North Atlantic. We aimed to further develop our understanding of the published predicted distribution of this species under present and future conditions (Beazley et al, 2021) and determine how different populations may be connected, isolated and/or retain larvae. We do so by identifying physical connections among currently occupied areas, estimating the maximal extent of larval transport, and determining the influences of location and depth on potential dispersal patterns.…”

“…However, its range extends from there to the Emerald Basin on the Scotian Shelf, off Nova Scotia, Canada (Figures 1, 2), where the species reaches its highest densities and forms extensive sponge grounds which have been protected from bottom contact fishing (Beazley et al, 2018). Further south it is generally only found in low numbers for reasons that are not well understood (Beazley et al, 2021). This species' distribution falls within the Temperate North Atlantic realm and both the Cold Temperate and Warm Temperate Northwest Atlantic biogeographic provinces of Spalding et al (2007), a distribution shared with at least 1664 other sponge species (Van Soest et al, 2012) such as Tetilla laminaris symmetrica and Clathria (Clathria) prolifera.…”