Benthic foraminifera and brachiopods from a marine cave in Spain: environmental significance

Abstract

Sediment samples from a marine cave in the Murcia region (eastern Spain) were analysed for grain size, total benthic foraminiferaand dead brachiopoda to obtain environmental information through physical and ecological data in order to understandthe benthic communities of cave environments and their ecological significance. A total of 100 foraminiferal and 7 brachiopodspecies were classified, highlighting the first occurrence in the western Mediterranean of Gwynia capsula (Jeffreys, 1859). Statistical analysis applied to foraminiferal data allowed the identification of three assemblages characterised by decreasing species diversity along the cave. This corresponded to a similar separation recognisable through changes in brachiopod species abundance and well-correlated with cave morphology. The relative abundance of epifaunal clinging-attached foraminifera as well as the rate of cave and sciaphilic/coralligenous Brachiopoda, thought to be representative of the degree of separation from marine conditions,were found to be highly correlated, increasing towards the inner cave. Our hypothesis was that despite the different lifestyles ofthese two groups, the strict correlation of environmental factors (i.e. light, nutrients, sediment texture, water parameters) changingalong the length of the cave determines a comprehensive environmental gradient, causing an increase in environmental stress that has similar effects on the different taxonomic groups.

Colonisers of the dark: biostalactite‐associated metazoans from “lu Lampiùne” submarine cave (Apulia, Mediterranean Sea)

“…The finding of living specimens of the micromorphic species G. capsula is of particular interest. This species has been reported mostly as dead specimens and disarticulated valves on cave sediments from a small number of caves in the Adriatic (Lošinj Island, Croatia: Simon, 2015; Simon & Willems, 1999); Levantine Sea (Cyprus: Jimenez et al., 2019) and the Hybero‐Provencal basin (CT12 cave, Murcia: Bergamin et al., 2020).…”

Taxonomic composition and assemblage structure of brachiopods from two submarine caves in the Aegean Sea, Eastern Mediterranean

“…Mediterranean, being typical of the infralittoralcircalittoral zone (Logan 1979(Logan , 2003Logan et al 2004) but is also commonly found in caves (Taddei Ruggiero 1994Ruggiero , 1996Grobe & Lüter 1999;Rosso et al 2013;Gerovasileiou et al 2015;Sanfilippo et al 2015;Guido et al 2017;Jimenez et al 2019;Bergamin et al 2020). Argyrotheca cuneata is also reported from the Northeastern Atlantic (Logan 1993).…”

“…Megathiris detruncata (Gmelin, 1791), a representative of the family Megathyrididae, is one of the most common species in both caves. It is common throughout the Mediterranean and Northeastern Atlantic (Logan 1979(Logan , 1993(Logan , 2003Harmelin et al 2003;Gerovasileiou et al 2015;Sanfilippo et al 2015;Gerovasileiou & Bailly 2016;Bergamin et al 2020). It is characterized by the broadly transverse shell ornamented by rounded ribs (Figure 3(a-d)).…”

“…Its shell is extremely small, not exceeding 1.4 mm in width, squarely transverse in outline, smooth except numerous growth lines, and strongly biconvex (Figure 4(a-d)). This species is usually found in shallow water, commonly occurring in caves (Logan 1979;Logan , 2003Grobe & Lüter 1999;Simon & Willems 1999;Harmelin et al 2003;Logan et al 2004;Rosso et al 2013;Gerovasileiou et al 2015;Bergamin et al 2020). It is also noted from the Northeastern Atlantic (Logan 1993).…”

“…conducted a morphometric analysis of the populations of Megathiris detruncata (Gmelin, 1791) from caves in the Western Mediterranean and Northeastern Atlantic. Recently Bergamin et al (2020) studied the composition and distribution patterns of the dead brachiopod assemblage found in cave sediment of the CT12 cave in southern Spain.…”