Coralline algae (Rhodophyta) in a changing world: integrating ecological, physiological, and geochemical responses to global change

Abstract

Coralline algae are globally distributed benthic primary producers that secrete calcium carbonate skeletons. In the context of ocean acidification, they have received much recent attention due to the potential vulnerability of their high‐Mg calcite skeletons and their many important ecological roles. Herein, we summarize what is known about coralline algal ecology and physiology, providing context to understand their responses to global climate change. We review the impacts of these changes, including ocean acidification, rising temperatures, and pollution, on coralline algal growth and calcification. We also assess the ongoing use of coralline algae as marine climate proxies via calibration of skeletal morphology and geochemistry to environmental conditions. Finally, we indicate critical gaps in our understanding of coralline algal calcification and physiology and highlight key areas for future research. These include analytical areas that recently have become more accessible, such as resolving phylogenetic relationships at all taxonomic ranks, elucidating the genes regulating algal photosynthesis and calcification, and calibrating skeletal geochemical metrics, as well as research directions that are broadly applicable to global change ecology, such as the importance of community‐scale and long‐term experiments in stress response.

Anatomical structure overrides temperature controls on magnesium uptake – calcification in the Arctic/subarctic coralline algae <i>Leptophytum laeve</i> and <i>Kvaleya epilaeve</i> (Rhodophyta; Corallinales)

“…There are concerns that as atmospheric pCO 2 increases and consequent ocean acidification increases, there will be negative impacts on the capacity of corallines to continue building these important substrates (e.g. McCoy and Kamenos, 2015), although there are experimental studies that find no negative impacts (e.g. Cox et al, 2017).…”

Light Absorption in Coralline Algae (Rhodophyta): A Morphological and Functional Approach to Understanding Species Distribution in a Coral Reef Lagoon

“…Similar exacerbations of light-stress have been documented for symbiotic scleractinian corals exposed to heat-stress (Warner et al, 1996;Iglesias-Prieto and Trench, 1997). Interestingly, corals share with coralline algae similar sensitivity to ocean warming and acidification, two major global threats that affect marine habitats (Hoegh-Guldberg et al, 2007;McCoy and Kamenos, 2015;Vásquez-Elizondo and Enríquez, 2016).…”

Characterizing the vulnerability of intertidal organisms in Olympic National Park to ocean acidification

“…Calcareous coralline algae are also ranked among the most sensitive taxonomic groups in our analysis, which is consistent with earlier work (Hall-Spencer et al, 2008;Kroeker et al, 2010), but may have specific implications for intertidal zone ecology. Coralline algae are key ecological players in intertidal processes such as CO 3 2− production, larval settlement, fish nurseries, and habitat formation (McCoy and Kamenos, 2015). Conversely, non-calcareous algae from the phyla Ochrophyta, Ceramiales, and Ulvophyceae appear to benefit from OA and are represented by 99 species at ONP (Table S3).…”