Differential vulnerability to climate change yields novel deep-reef communities

Abstract

The effects of climate-driven ocean change on reef habitat-forming species are diverse(1,2) and can be deleterious to the structure and functioning of seafloor communities(3-5). Although responses of shallow coral-or seaweed-based reef communities to environmental changes are a focus of ecological research in the coastal zone(1,4-6), the ecology of habitat-forming organisms on deeper mesophotic reefs remains poorly known. These reefs are typically highly biodiverses(7,8) and productive as a result of massive nutrient recycling(9). Based on seafloor imagery obtained from an autonomous underwater vehicle(8), we related change in community composition on deep reefs (30-90 m) across a latitudinal gradient (25-45 degrees S) in southeastern Australia to high-resolution environmental and oceanographic data, and predicted future changes using downscaled climate change projections for the 2060s(10-12). This region is recognized as a global hotspot for ocean warming(13). The models show an overall tropicalization trend in these deep temperate reef communities, but different functional groups associate differentially to environmental drivers and display a diversity of responses to projected ocean change. We predict the emergence of novel deep-reef assemblages by the 2060s that have no counterpart on reefs today, which is likely to underpin shifts in biodiversity and ecosystem functioning.

Subregional differences in groundfish distributional responses to anomalous ocean bottom temperatures in the northeast Pacific

“…Warm/medium/cold years are based on 0.66 standard deviations from the overall mean with the same format as in Figure 3. Lines represent the overall mean SST (dotted) and BT (dashed) across survey years reorganized (Hazen et al, 2013;Marzloff et al, 2018;Selden, Batt, Saba, & Pinsky, 2017) within the thermal ecoregions.…”

Potential distribution of Notopterygium incisum Ting ex H. T. Chang and its predicted responses to climate change based on a comprehensive habitat suitability model

“…The growth, development, and reproduction of plants are limited by climatic and other environmental factors. Global warming is likely to result in changes in biological habitats, losses of regional species diversity, and increases in the risk of species extinction (Anderson, ; Marzloff et al, ; Pacifici et al, ; Urban, ). Topography affects the redistribution of moisture and heat in the natural environment; therefore, topography is an important driver of plant species distributions, especially for alpine plants, and in mountainous regions, macrotopographies are usually large enough to provide refuge for plant species under changing climates (Myan, Walker, & Paramor, ).…”

“…The growth, development, and reproduction of plants are limited by climatic and other environmental factors. Global warming is likely to result in changes in biological habitats, losses of regional species diversity, and increases in the risk of species extinction (Anderson, 2013;Marzloff et al, 2018;Pacifici et al, 2015;Urban, 2015).…”

Integrated assessment of the spatial distribution and structural dynamics of deep benthic marine communities

“…, Marzloff et al. ). For example, increases in temperature to above 0°C could lead to shifts from species communities tolerant to freezing temperatures to more generalist types of species communities (Griffiths et al.…”

“…Our results suggest that increases in pelagic food sources are unlikely to lead to major structural changes in benthic communities, as almost all elements in the QNM increased in similar proportions. However, other factors that will change in the future, such as temperature and ocean acidification, are not captured in our network model, but are likely to affect the distributions of species and functional groups differentially (Constable et al 2014, Griffiths et al 2017, Marzloff et al 2018. For example, increases in temperature to above 0°C could lead to shifts from species communities tolerant to freezing temperatures to more generalist types of species communities (Griffiths et al 2017).…”