Intertidal and subtidal benthic foraminifera in flooded caves: Implications for reconstructing coastal karst aquifers and cave paleoenvironments

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

“…Species typical of clusters A and B plot on the negative side of the first axis and are associated with the fine sediment fractions (silt and clay), but also with gravel. The same preference by P. corrugata, S. vivipara and S. emaciatum for pelitic sediment was recognised by Little & van Hengstum (2019). This indicates that they prefer to attach to larger fragments associated with pelitic sediment.…”

“…Consequently, the high variability of sediment texture may not be attributed to high spatial variability of hydrodynamic conditions; actually, a low-energy environment may be supposed in the cave for the general presence of pelitic sediment (Table 2). Also, the micrite coat, which mainly constitutes the fine sediment fraction and is likely due to autochthonous carbonate precipitation as recognised in marine caves of Mallorca Island and Bermuda (Fornós et al, 2009;Little & van Hengstum, 2019), confirms such conditions. The clear succession of distinct foraminiferal assemblages along the cave also indicates the absence of significant post-mortem transport, which would have caused the mixing of fauna from different sections of the cave.…”

“…The high abundance of BF in these samples may indicate a high nutrient availability corresponding to cluster B, while the increasing opportunistic behaviour of P. corrugata moving away from the entrance may represent the response to increasing environmental stress (Alve, 1995(Alve, , 2003. Consequently, the role of organic carbon recognised by Little & van Hengstum (2019) as a main factor influencing BF in the Bermudian caves may be supposed also for the CT12 cave.…”

“…This assemblage was dominated by S. emaciatum, which was also rather common in the CT12 cave. The same species, but also the less abundant Sejunctella sp., represented the characterising species of the Subtidal Marine Assemblage recognised in other Bermudian caves by Little & van Hengstum (2019) and thought to be associated with organic carbon from marine sources. Another common species in this assemblage was S. emaciatum, reported as an indicator of oxygenated saline groundwater, frequent also in the CT12 cave.…”

“…The count of BF was carried out in the total assemblage and considered as the sum of several generations over time, including those that were possibly living at the time of sampling. This approach prevents seasonal variability from affecting foraminiferal species (Duchemin et al, 2008), supplying information on mean environmental conditions (Leorri et al, 2008) and allowing the identification of distinct environments (Little & van Hengstum, 2019). In order to prevent the inclusion of reworked or transported specimens, only well-preserved Fig.…”