Marine cave biota of the Tarkhankut Peninsula (Black Sea, Crimea), with emphasis on sponge taxonomic composition, spatial distribution and ecological particularities

Abstract

The main objectives of this study are the establishment of a detailed description of five semi-submerged and shallow-water marine caves from the Tarkhankut Peninsula (Crimea), their biological characteristics with particular attention to species composition, and the distribution of sponge assemblages in these caves. Three semi-submerged and two submerged caves with lengths of 9–131 m and volumes of 61–3060 m3 have been investigated. All of them are karst-abrasive or karst in origin. In the investigated caves, we inventoried seven sponge species. All were recorded species of Porifera belong to the class Demospongiae and have previously been recorded also in adjacent open sea waters. These species are tolerant to different hydrological conditions, mostly temperature and salinity. Some of them have wide geographic distribution. The species composition of sponges from the shallow water caves of Crimea is quite different from the sponge composition in Mediterranean caves. This could be due to the geographic isolation of the Black Sea and the differences in the hydro-chemical parameters of the milieu (water salinity in Tarkhankut is 18–21‰).

Ecological patterns in anchialine caves

“…This pattern was shown in all areas, except those with chemosynthesis, such the site “c” in El Aerolito, where chemosynthetic production of dissolved organic carbon allows a greater density of macroorganisms [ 33 , 65 ]. In fact, the highest species richness in terrestrial and underwater caves has been reported near their entrances [ 3 , 4 , 26 , 68 ]. Caves lacking a direct connection to the sea, but still being close to the coastline, exhibit an increased probability that “new” organisms can be transported into the cave as a result of hydrological changes, such as sea level rise [ 42 , 69 ].…”

Integrative taxonomy of the cave-dwelling mysids of the genus Hemimysis

“…doi.org/xx.xxxx/xxxxxxxx.xxxx.xxxxxx) and Bulgaria ( Fig. 1, points 3-6) (see Ereskovsky et al, 2016Ereskovsky et al, , 2018. Hemimysis l. lamornae was collected in the English Channel in a darkened niche of breakwaters (Table S1, see supplemental material online).…”

“…Living in cave conditions can lead to niche partitioning and the evolution of closely related species living in neighbouring caves or even different parts of the same cave (Lejeusne & Chevaldonn e, 2006;Neiber, Hansen, Iliffe, Gonzalez, & Koenemann, 2012;Rastorgueff, Harmelin-Vivien, Richard, & Chevaldonn e, 2011). The study of fauna living in the marine caves of the Black Sea may clarify the species composition of poorly studied underwater cave communities as well as the evolution of species adapted to low salinity (Ereskovsky et al, 2018;Ereskovsky, Kovtun, & Pronin, 2016). One of the most interesting targets of these studies is the cavedwelling mysids representing genus Hemimysis G.O.…”

Sponge community of the western Black Sea shallow water caves: diversity and spatial distribution

“…Sponges (Phylum Porifera) represent one of the most abundant animal phyla in many benthic ecosystems ( Bell & Smith, 2004 ) and can constitute the dominant sessile organism group in marine cave environments ( Sarà, 1962 ; Corriero et al, 2000 ; Richter et al, 2001 ; Bell, 2002 ; Gerovasileiou & Voultsiadou, 2012 ; Gerovasileiou & Voultsiadou, 2016 ; Gerovasileiou et al, 2016 ; Radolović et al, 2015 ; Ereskovsky, Kovtun & Pronin, 2016 ). The sponge fauna of marine semi-submerged caves has been investigated predominantly in the Mediterranean Sea ( Sarà, 1958 ; Sarà, 1961a ; Sarà, 1961b ; Laborel & Vacelet, 1959 ; Labate, 1964 ; Vacelet, 1976 ; Vacelet, 1996 ; Pansini & Pronzato, 1982 ; Corriero et al, 1997 ; Corriero et al, 2000 ; Corriero, 1989 ; Knittweis et al, 2015 ; Dimarchopoulou, Gerovasileiou & Voultsiadou, 2018 ), although a few studies were performed in Ireland ( Bell, 2002 ), in the Caribbean area ( Macintyre et al, 1982 ; Hart, Manning & Iliffe, 1986 ; Kobluk & Van Soest, 1989 ), and the Black Sea ( Ereskovsky, Kovtun & Pronin, 2016 ). Here, it was clearly demonstrated that superficial caves do not resemble submerged caves in terms of benthos diversity and community structure.…”

“…Our knowledge on the biodiversity of the Black Sea sponges is scarce; data describing the sponge diversity in its caves is practically non-existent, except for one publication on Crimean cave sponges ( Ereskovsky, Kovtun & Pronin, 2016 ).…”