EUNIS habitat classification 2017 > M - Marine benthic habitats > ME1 - Upper bathyal rock > ME15 - Mediterranean upper bathyal rock > ME152 - Biocenosis of Mediterranean upper bathyal caves and ducts in total darkness

Biocenosis of Mediterranean upper bathyal caves and ducts in total darkness

Quick facts

EUNIS habitat type code ME152
Relation to Resolution 4 habitat type (used for designation of Emerald sites)

Description (English)

Very large submerged cavities especially present in drowned karstic networks, isolated little cavities and microcavities in heaps of stones and within certain concretions.
The caves in total darkness are enclaves of the aphotic area in the littoral area; they present extremely original environmental conditions, close to those found on the continental slope. The two key factors are the absence of light, which rules out photosynthetic organisms, and confinement, which rules out organisms which have a strong trophic requirement. Water renewal in the dark chambers is usually very slight or occasional and depends on local topographical, bathymetrical and geographical factors. The great hydrological stability is indicated by anomalies of temperature, extremely oligotrophic conditions, and biochemical parameters. Positive thermal anomalies are typical of caves with a rising profile (a frequent case in karstic caves) and negative anomalies have been noticed in the rare caves with a descending profile. The very great reduction in the trophic addition from the outside brings about a drastic selection of the animals established in this habitat. The rate of biological cover of the walls of this habitat may be 80 to 50% in the richest areas but can be almost nil in the most confined parts. The selection of trophic groups and morphological groups, as well as the spatial organisation, are governed by environmental conditions that are peculiar to each cave. This biocenosis includes a significant portion of typically deep-sea species, the most original of these being found in caves with a descending profile, with a thermal regime similar to that of the Mediterranean deeps.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Not available

Other classifications

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 2007 (revised descriptions 2012) A6.1 Deep-sea rock and artificial hard substrata narrower
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type Comment
EUNIS Habitat Classification 200410 A6.1 Deep-sea rock and artificial hard substrata same
EUNIS Habitat Classification 200308 A5.1 Deep-sea rock and artificial hard substrata same
EUNIS Habitat Classification 200202 A5.1 Deep-sea rock and artificial hard substrates same
EUNIS Habitat Classification 199910 A5.1 Bathyal zone hard substrates same
EUNIS Habitat Classification 199811 A5.1 Bathyal zone rock (continental slope floor) same
Palaearctic Habitat Classification 199905 11.211 Bathyal benthic communities wider
Palaearctic Habitat Classification 1997 11.211 Bathyal benthic communities wider
Palaearctic Habitat Classification 1996 11.211   wider
Palaearctic Habitat Classification 1993 11.211   wider
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