‘Anchialine’ redefined as a subterranean estuary in a crevicular or cavernous geological setting

Abstract

An improved understanding of the anchialine ecosystem and geology warrants a redefinition of the term 'anchialine.' Originating from subareal biological observations, the term anchialine now encompasses chemical, physical, geological and biological elements within the subterranean realm. We propose a more accurate definition of the term anchialine as 'a tidally-influenced subterranean estuary located within crevicular and cavernous karst and volcanic terrains that extends inland to the limit of seawater penetration.' This subterranean estuary is characterized by sharp physical and chemical stratification and merges with a marine system at the coast and a groundwater system inland. The anchialine ecosystem supports a relatively diverse biotic assemblage of stygobiotic species of marine origin dominated by members of Crustacea, both numerically and by species richness.

Life in the Underworld: Anchialine cave biology in the era of speleogenomics

“…The term anchialine, from the Greek "anchialos" meaning "near the sea", is generally used in reference to 'tidally-influenced subterranean estuaries within crevicular and cavernous karst and volcanic terrains that extend inland to the limit of seawater penetration' (Stock, 1986;Iliffe, 1992;Bishop et al, 2015). Despite tidal influences acting through small conduits and/or the porosity of the surrounding limestone or volcanic rock, anchialine systems have restricted biological connectivity with adjacent water bodies and their associated ecosystems Becking et al, 2011;Bishop et al, 2015).…”

“…Despite tidal influences acting through small conduits and/or the porosity of the surrounding limestone or volcanic rock, anchialine systems have restricted biological connectivity with adjacent water bodies and their associated ecosystems Becking et al, 2011;Bishop et al, 2015). Anchialine caves are occasionally interconnected, forming extensive underground networks and giving rise to large and spatially complex habitats (e.g., cenotes in the Yucatan Peninsula, Mexico, Beddows et al, 2007;Mylroie & Mylroie, 2011).…”

World Register of marine Cave Species (WoRCS): a new Thematic Species Database for marine and anchialine cave biodiversity

“…Although a consensual definition was published (Stock et al 1986), it has not been completely endorsed by the community, including some of the authors. In particular, defining what an anchialine cave is seems rather complex as there is an uninterrupted continuum of variation between strictly submarine and purely freshwater caves (Bishop et al 2015). The essential point here is to reach a consensus about whether WoRCS should include data on inland freshwater caves and their species.…”

Carbon Cycling in the World's Deepest Blue Hole

“…For the past three decades, studies have described vertical gradients in physical, chemical, and biological features of the water columns of blue holes and cenotes (e.g., Becking et al, ; Bishop et al, ; Mylroie et al, ; Pohlman, ; Schwabe & Herbert, ; Seymour et al, ; van Hengstum et al, ). Yet elemental cycles, especially carbon cycling, remain poorly understood in these environments, with only a few reports to date (e.g., Brankovits et al, ; Martin, )—that have largely focused on cenotes.…”