Heading for New Shores: Projecting Marine Distribution Ranges of Selected Larger Foraminifera

Abstract

The distribution of modern symbiont-bearing larger foraminifera is confined to tropical and subtropical shallow water marine habitats and a narrow range of environmental variables (e.g. temperature). Most of today's taxa are restricted to tropical and subtropical regions (between 30°N and 30°S) and their minimum temperature limits are governed by the 14 to 20°C isotherms. However, during times of extensive global warming (e.g., the Eocene and Miocene), larger foraminifera have been found as far north as 50°N (North America and Central Europe) as well as towards 47°S in New Zealand. During the last century, sea surface temperatures have been rising significantly. This trend is expected to continue and climate change scenarios for 2050 suggest a further increase by 1 to 3°C. We applied Species Distribution Models to assess potential distribution range changes of three taxa of larger foraminifera under current and future climate. The studied foraminifera include Archaias angulatus, Calcarina spp., and Amphistegina spp., and represent taxa with regional, superregional and global distribution patterns. Under present environmental conditions, Amphistegina spp. shows the largest potential distribution, apparently due to its temperature tolerance. Both Archaias angulatus and Calcarina spp. display potential distributions that cover currently uninhabited regions. Under climate conditions expected for the year 2050, all taxa should display latitudinal range expansions between 1 to 2.5 degrees both north- and southward. The modeled range projections suggest that some larger foraminifera may colonize biogeographic regions that so far seemed unsuitable. Archaias angulatus and Calcarina spp. also show an increase in habitat suitability within their native occurrence ranges, suggesting that their tolerance for maximum temperatures has yet not been fully exploited and that they benefit from ocean warming. Our findings suggest an increased role of larger foraminifera as carbonate producers and reef framework builders in future oceans.

Evolutionary significance of the microbial assemblages of large benthic Foraminifera

“…We argue that the current predicted poleward expansion of some LBF species as global warming progresses partly hinges on their microbiome. Range expansions of LBF have triggered substantial changes in ecosystem function, including shifts in species diversity, carbonate production, and ecological impacts on native biota (Langer & Hottinger, ; Langer, ; Weinmann et al, ,b ; Langer et al, ). The potential for the recombination of different eukaryotic and prokaryotic partners (Fig.…”

“…By contrast, on the GBR and in the Indo‐Pacific, LBF diversity is higher among the diatom‐bearing hyaline taxa, which tend to be the dominant species in oligotrophic reef‐associated environments. Diatom‐bearing species have dominated shallow platforms throughout the Cenozoic (Wilson et al ., 1998; Morsilli et al, ; Novak & Renema, ), and are good candidates to become the dominant calcifiers in carbonate environments in the future (Weinmann et al, ). This is largely due to their high tolerance to a broad range of temperature, nutrient, and light levels (Weinmann et al, ; Langer et al, ; Prazeres, Uthicke, & Pandolfi, ; Prazeres et al, ), as well as their proven capacity to colonise new habitats and areas efficiently.…”

Foraminiferal holobiont thermal tolerance under climate change – Roommates problems or successful collaboration?

“…Their carbonate production is estimated as at least 5% of the annual production in reef and carbonate shelf environments (Langer, 2008;Langer et al, 1997). Temperature is a major factor in the distribution of LBF that exhibit distinct thresholds for reproduction, survival, bleaching, and calcification (Evans et al, 2015;Hallock et al, 2006a;Langer et al, 2012;Langer and Hottinger, 2000;Schmidt et al, 2011;Titelboim et al, 2019;Weinmann et al, 2013). The symbiont composition of LBF appears to be strongly controlled by temperatures (Momigliano and Uthicke, 2013;Prazeres, 2018;Prazeres et al, 2017;Prazeres and Renema, 2019;Schmidt et al, 2018) which explains the observations that species-specific thermal tolerance is associated with more diverse algal symbionts (Stuhr et al, 2018).…”

Biostratigraphy, microfacies and paleoecology of the Asmari Formation, Interior Fars province, Zagros Basin, Iran

“…The diverse porcellaneous biotas suggests lagoonal or inner shelf conditions in a shallow water environment. The presence of abundant specimens of Archaias indicates a water depth of less than 20 meters (geel 2000;corda & Brandano 2003;vaziri-MogHaddaM et al 2006;BaSSi et al 2007;Brandano et al 2009;BaSSi & neBelSicK 2010, langer & Hottinger 2000Murray 1991;HallocK & glenn 1986;WeinMann et al 2013). Seagrass or algal substrates are indicated by the presence of ephiphytic foraminifera such as Archaias and Peneroplis.…”