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The caves on Antalya cliffs are of three origin; sea caves, tufa caves and flank margin caves. Sea caves are formed due to wave action on weak parts of the rock. Because the rocks of the Antalya cliffs are heterogeneous and strength varies in a wide range, weak parts of the cliffs are susceptible to cave formation. Tufa caves occurred as blind holes behind tufa curtains which deposited on tufa cascade environment of deposition. The obvious distinguishing features of tufa caves are primary sedimentary structures instead of corrosion morphologies. The flank margin caves occurred due to mixing corrosion at sea and groundwater interface. In this study more attention has been paid on porosity development and related cave formation due to mixing corrosion. Mixing corrosion is a process in which mixed water dissolves calcium carbonate rock, where groundwater and sea water interfere. Cavities which occur in this process can join together and form big chambers. When rock load on this chambers exceeds rocks strength, the roof may collapse and fall into the chamber. This fallen block is also subject to further dissolution resulting in enlargement of the cave. Entrances of the caves on the cliffs are concentrated between present sea level and 5 m below this level. Similarly, on the sea level caves depth of the caves is around 5 m. Starting from a time of constant sea level in the past, and following sea level rise, mixing corrosion and flank margin cave development should have been continued. [ABSTRACT FROM AUTHOR]

Anchialine caves in coastal locations develop in two ways: by pseudokarst processes that form talus caves, sea caves, tafoni, fissure caves and lava tubes, and by karst dissolutional processes that form stream caves, flank margin caves, and blue holes. Pseudokarst caves are of minor importance in anchialine cave habitat development, with some lava tubes being notable exceptions. Dissolution caves provide the most extensive, variable, and long-term environments for anchialine habitats. The Carbonate Island Karst Model (CIKM) allows dissolutional cave development in carbonate coasts to be understood as the interplay between freshwater and marine water mixing, sea-level change, rock maturity, and interaction with adjacent non-carbonate rocks. Glacioeustatic sea-level changes of the Quaternary have moved all coastal anchialine cave environments repeatedly through a vertical range of over 100 m, and modern anchialine environments could not develop at their current elevations until ~4,000 years ago when sea level reached its present position. Blue holes form by a variety of mechanisms, but the most common is upward stoping and collapse from deep dissolutional voids. As a result, they provide vertical connection between different levels of horizontal cave development produced by a variety of earlier sea-level positions. Blue holes are overprinted by successive sea-level fluctuations; each sea-level event adds complexity to the habitats within blue holes and the cave systems they connect. Blue holes can reach depths below the deepest glacioeustatic sea-level lowstand, and thereby provide a refugia for anchialine species when cave passages above are drained by Quaternary sea-level fall. Blue holes represent the most significant anchialine cave environment in the world, and may provide clues to anchialine cave species colonization and speciation events. [ABSTRACT FROM AUTHOR]

The article focuses on the study concerning the co-existence of large populations of several mysid species in oligotrophic underwater marine caves located on the French Mediterranean coast. It examines the carbon and nitrogen stable isotope compositions of species to determine their trophic relationships. It shows that hemimysis speluncola feeds mainly on zooplankton and phytoplankton outside the cave.

Abstract: This paper aims to identify the spatial patterning of burning and occupation within an early Middle Stone Age (MSA) sea cave in the Western Cape Province of South Africa by creating a multidimensional model of archaeomagnetic data recovered from all excavated units. Magnetic susceptibility and other mineral magnetic parameters are shown to provide an excellent proxy for the anthropogenic alteration and spread of burnt material into the surrounding unaltered cave deposits. The identification of combustion features and areas of occupation or different activities within the site can be determined because the movement of people throughout the cave mixes magnetically strong hearth material with magnetically weak unaltered sediments. This is also indicated by micromorphological analysis. The degree of enhancement is also shown to indicate the extent to which a deposit has been altered, and therefore, intensity of occupation, because multiple heatings of deposits are needed to form the concentrations of iron minerals occurring in some layers. This is further supported by a comparison with artifact density for the layers. Variation in the magnetic values between different areas of the site is noted with major occupation or fire building occurring in the front of the cave during earlier MIS 6 periods, while during later MIS 5 periods the entire cave is occupied intensively. The oldest, MIS 11 deposits at the rear of the cave indicate no evidence of enhancement and an apparent absence of any anthropogenic signature. [ABSTRACT FROM AUTHOR]

The article discusses a study on the existence of Herbstia Nitida Manning and Holthius (Decapoda, Brachyura) in a submarine cave in southeastern Italy. It says that Grotta di Cicolo, a shallow marine cave was explored by scuba divers in 2002 to collect vagile fauna samples wherein all decapoda collected was identified through stereomicroscope. Moreover, the similarity between Herbstia Nitida with Herbstia Condyliata might have been the reason why its has been overlooked in the past studies.

Abstract: Coral reef cavities, crevasses, and caves are inhabited by cryptic communities. The sediments within the submarine Daidokutsu Cave (29m water depth) on the fore-reef slope of Ie Island, Okinawa, Japan, preserve a fossil record of cryptic bivalve species over the past 7000years. The record suggests that infilling of cavities caused a progressive decrease in the exchange of water between the interior and exterior of the cave, resulting in a decline in food supply to the cave. To test this hypothesis, the light conditions within the cave were reconstructed from the spatial and temporal distributions of algal symbiont-bearing large benthic foraminifers, based on the assumption that infilling of reef cavities would have resulted in reduced light intensity within the cave. The results show that progressive darkening of the cave occurred by about 5130yr BP, synchronous with a weakening in water flow within the cave. This synchronicity indicates that infilling of cavities and narrowing of the cave entrance might cause declines in the exchange of water between the interior and exterior of the cave, as well as in light intensity within the cave. These resulted in a deficiency in food in the cave, thereby affecting the species composition of cavernicolous bivalves. [Copyright &y& Elsevier]

Abstract: Submarine caves at the Cape of Otranto in South-Eastern Italy host eccentric stalactites which have been recently recognised as completely biogenic. The possibility to use the calcareous tubules of Polichaete forming the inner texture of the stalactites as suitable samples for radiocarbon dating is described. AMS radiocarbon dating analyses performed on samples taken at different positions along the longitudinal axis of three different stalactites allowed to obtain information about the duration of the formation phase, to determine the growth-rate at different stages of evolution and to establish the complete submarine origin of the stalactites. The comparison of the radiocarbon data obtained for the different studied structures reveal also similarities as well as important differences between single stalactites, supplying new information about their response to environmental changes in the same, confined ecosystem. [Copyright &y& Elsevier]

Abstract: Thermal anomalies up to 4 °C above the climatological mean caused dramatic mass mortalities in benthic ecosystems of the NW Mediterranean during the summer heat waves of 1999 and 2003. Information on the sessile communities of the submarine cave of Bergeggi (Ligurian Sea) was taken in 1986 and 2004, i.e. before and after the two thermal events, using wire-frame photography in four sectors of the cave ecosystem with different morphologies and environmental features. Percent cover data of growth forms (as descriptors of the structural aspects of cave ecosystem) and feeding guilds (functional aspects) were analysed by multivariate and univariate techniques. Differences in trophic organisation and total biotic cover in the four sectors were significant and consistent in the two years. Thus, food web constraints (such as water confinement and trophic depletion), that are mostly dependent on topography, underwent no major change following the thermal events. On the contrary, structural aspects changed across time, 3-dimensional growth forms being replaced by 2-dimensional ones, leading to a general homogenisation of the cave communities. Positive thermal anomalies are thought to have selectively killed erect and massive organisms, their replacement by encrusting organisms possibly representing a phase in cave recolonisation. Submarine caves are poorly resilient ecosystems, and understanding their capacity of recovery after major disturbances is mandatory for their management and conservation. [Copyright &y& Elsevier]

The common shrimps of the genus Palaemon are often reported as living in Mediterranean submarine caves. The present study quantifies the distribution pattern of a Palaemon spp. populations throughout 1 year of observations in a shallow submarine cave in South-eastern Italy, Ionian Sea. The cave was subdivided into six sectors from the entrance towards the inner portion of the ‘blind cave’ and 16 dives (four per season, during both day and night) were performed with SCUBA equipment. The population was estimated in situ using visual census. Four different species of Palaemon were identified. This study has shown that Palaemon spp. assemblages live throughout the year in submarine caves. Moreover, the results suggest submarine caves play an important role in the biology of Palaemon spp. populations, by providing refuge, juvenile recruitment and food resources. [ABSTRACT FROM AUTHOR]

Two new species of Loricifera, Pliciloricus cavernicola sp. nov. and Australoricus oculatus gen. nov. et sp. nov., have been found in two submarine caves, Jim's Cave and Fish Rock Cave, off the coast of New South Wales, Australia. This is the first discovery of Loricifera from Australia and additionally from marine caves. This paper is the third paper concerning the meiofauna animals from the two caves. Pliciloricus cavernicola sp. nov. is characterized by an adult having a large tripartite mouth cone with six oral stylets; clavoscalids with fine lines; a short, robust double organ; small leg-shaped scalids with three stiff hairs; simple claw-shaped scalids; reduction of trichoscalid basal plates in the first two rows and a midventral plica with three ridges. Australoricus oculatus gen. nov. et sp. nov. is characterized by a Higgins-larva having a pair of pigmented eyes; the 2nd scalid row missing; six smooth and long filiform scalids in the 6th row; six rectangular plates with two teeth in the 7th row; three pairs of ventral setae; two large lateral lorica plates; three pairs of posterior setae and toes with balloon-shaped mucrones. [ABSTRACT FROM AUTHOR]

Abstract: An application of an artificial neural network (ANN) combined with thermographic analysis for estimating the depth of eroded caves in a seawall is presented in this paper. A model experiment was first conducted in a sandbox using a thermographic device to detect the interior conditions of a structure from its temperature changes measured on the surface. The temperature difference calculated from the air temperature and the measured concrete surface point on a thermographic image was obtained for the neural network. Based on the laboratory data, an optimum ANN model for the estimation of the depth of eroded caves in a seawall was established by using four input factors: the site temperature, humidity, thermographic area, and the temperature difference. The model was verified using data from a seawall in Tainan City, Taiwan. From the results, it was found that the present ANN model efficiently estimates the depth of eroded caves in a seawall. [Copyright &y& Elsevier]

Submarine caves at the Cape of Otranto (SE, Italy) host pseudostalactites. Only recently have they been recognised as originating mainly from the marine tube worm Protula tubularia (Serpulidae, Polychaeta). Their formation depends on the adaptability, life history and behaviour of that species in the cave habitat. The dating of calcareous tubes in the pseudostalactite core represents the first attempt to describe the formation of such bio-construction, and the gregarious behaviour of the species. Calcareous tubes along the core axis of three pseudostalactites removed from the cave lu Lampiùne (Otranto, South East Italy) have been dated using the 14C method. Measures established ages from 2600 to 5000 years for the three structures. This extremely long period (when compared with the life span of each worm) suggests that each tube aggregation is the result of punctuated growth periods alternated with long standstill phases. At the end of a growth period, each tube aggregation was covered with a brownish concretion, completing the pseudostalactite. [ABSTRACT FROM AUTHOR]

Abstract: Two hypotheses have been proposed to explain the origin of marine isotope stage (MIS) 11 deposits in small Bermudian caves at +21m above modern sea level: (1) a +21m MIS 11 eustatic sea-level highstand, and (2) a MIS 11 mega-tsunami event. Importantly, the foraminifera reported in these caves have yet to be critically evaluated within a framework of coastal cave environments. After statistically comparing foraminifera in modern Bermudian littoral caves and the MIS 11 Calonectris Pocket A (+21m cave) to the largest available database of Bermudian coastal foraminifera, the assemblages found in modern littoral caves – and Calonectris Pocket A – cannot be statistically differentiated from lagoons. This observation is expected considering littoral caves are simply sheltered extensions of a lagoon environment in the littoral zone, where typical coastal processes (waves, storms) homogenize and rework lagoonal, reefal, and occasional planktic taxa. Fossil protoconchs of the Bermudian cave stygobite Caecum caverna were also associated with the foraminifera. These results indicate that the MIS 11 Bermudian caves are fossil littoral caves (breached flank margin caves), where the total MIS 11 microfossil assemblage is preserving a signature of coeval sea level at +21m. Brackish foraminifera (Polysaccammina, Pseudothurammina) and anchialine gastropods (∼95%, >300 individuals) indicate a brackish anchialine habitat developed in the elevated caves after the prolonged littoral environmental phase. The onset of sea-level regression following the +21m highstand would first lower the ancient brackish Ghyben-Herzberg lens (<0.5m) and flood the cave with brackish water, followed by drainage of the cave to create a permanent vadose environment. These interpretations of the MIS 11 microfossils (considering both taphonomy and paleoecology) are congruent with the micropaleontological, hydrogeological and physical mechanisms influencing modern Bermudian coastal cave environments. In conclusion, we reject the mega-tsunami hypothesis, concur with the +21m MIS 11 eustatic sea-level hypothesis, and reiterate the need to resolve the disparity between global marine isotopic records and the physical geologic evidence for sea level during MIS 11. [Copyright &y& Elsevier]

The discovery of conspicuous populations of the rare species Petrobiona massiliana is reported from shallow water karstic caves of Sardinia. The morphological comparative analysis versus previous data from the entire geographic range highlights that spicular traits seem to be highly conservative in contrast with a notable plasticity of growth form. Lifestyle and adaptive strategies that favoured the successful spread of P. massiliana in karstic caves and its persistence as extremely isolated populations in a fragmented habitat are discussed together with potential environmental constraints. The data indicate that conservation of this Mediterranean palaeoendemic species with a spot-like distribution may be a challenge for the western Mediterranean Marine Protected Areas to confer protection to numerous co-occurring cave-dwelling species. [ABSTRACT FROM AUTHOR]

A new species of Sphaerosyllis (Syllidae, Exogoninae), S. iliffei n. sp., is described from interstitial habitats of Montaña de Arena in the Atlantida Tunnel, a marine lava tube of La Corona volcano (Lanzarote, Canary Islands). The new species is characterized by lacking eyes, parapodia bearing four heterogomph compound falcigers with blade lengths decreasing from dorsalmost to ventralmost, and one supra-acicular simple chaeta distally serrated from first chaetiger. Females brood eggs ventrally, attached juveniles occurs to chaetiger 12. Males have long ventral cirri from chaetiger 13 backwards, without natatory chaetae. Sphaerosyllis iliffei n. sp. is the first record of a troglobitic Syllidae, with its unpigmented body, the apparent absence of eyes, and the females ventrally brooding a single embryo. [ABSTRACT FROM AUTHOR]

The Jameos del Agua is a natural anchialine cave lagoon that has been developed as a tourist attraction. It is semi-illuminated due to a partial collapse of the ceiling (known as “jameo”). A fine carpet of benthic diatoms covers the bottom, in 0.5–2 m depth of water, of the tidally influenced and fully marine lagoon. Interstitial polychaetes inhabit this diatomean carpet and the lava rubble mixed with sand and gravel. During the last decades, the echiurid Bonellia viridis became very abundant and its bioturbation activities have changed the natural bottom conditions. The whitish fecal material from B. viridis formed sediment mounds that sharply contrast with the black volcanic rock. This new habitat have been colonized by several endemic species (e.g., Fauveliopsis jameoaquensis), but also by abundant stygoxene macro- and meiofaunal opportunistic species that compete with the endemic stygobities. The most recent colonizers are mainly deposit-feeding polychaetes that take advantage of the high amount of trophic resources available (e.g., Notomastus spp., Trichobranchus glacialis, Aphelochaeta marioni, Cirrophorus lyra). As a result of the recent colonizations, it is necessary to establish monitoring of the communities and to evaluate the viability of controlling the population of B. viridis in the lagoon, since these alterations can also affect the endemic populations living in the water column. [ABSTRACT FROM AUTHOR]

Four juvenile instars of Deeveya medix (Instars I, II, III, and V) from marine caves and blue holes in the Bahamas are described and illustrated. The ontogeny of the species is compared with that of D. spiralis Kornicker & Iliffe, 1985, and D. bransoni Kornicker & Palmer, 1987 and found to be similar. Criteria are presented for identifying stages of species of Deeveya. Each lamella of the furca of known species of Deeveya bears 3 claws on instar I, 4 on instar II, 5 on instar III, 6 on instar IV, and 7 on instar V and the adult. [ABSTRACT FROM AUTHOR]

Fekete-hegy is located at the central part of the Bakony-Balaton Highland Volcanic Field (BBHVF). The volcanic complex of Fekete-hegy comprise at least 3 maar/tuff rings and 2 eroded Strombolian-type scoria cones from the Pliocene age. This paper is focused on degradation of these two eroded scoria cones (Boncsos-teto, Gajos-teto) from morphometrical point of view. According to morphometry of present remnants (mostly Wco) with Porter's equations the original geometry of the scoria cones were established. We could calculate erosion rate of the study localities on the basis of differences between present and supposed original size of the cones. Possibly asymmetric profile of Boncsos-teto is caused by several processes including: (1) deflection of ash by wind drift; (2) phreatomagmatic stage(s) during the emplacement of the cone; (3) asymmetric location of welded structures within the cone; (4) truncation of adjacent volcanic eruption(s) or (5) post-volcanic landslide(s). Finally, differences in present shape and morphometry between Gajos-tetõ and Boncsos-teto we could interpret as Boncsos-teto have to be younger than we have considered in previous. [ABSTRACT FROM AUTHOR]

The aim of this study to demonstrate that how, and in which form sea caves develop in structurally different basaltic lavas and pyroclastites of these kinds. Also influenced by marine erosion, the dimensions and morphology of sea caves principally depend on the structural behaviour of the enclosing basaltic lavas and pyroclastics. In basalt volcanic areas sea caves can form in columnar and irregularly jointed basaltic lava; through opening up and further shaping of primarily existing caverns; in lava deltas; by the excavation of embedded volcanic agglomerate or slack structured aa lava from between thick and primarily existing caverns; in pillow lava; in basaltic dyke; along the border of a basaltic dyke and thick hydrovolcanic tuff and in basaltic tuff. The aim of this study is to demonstrate that how and in which form sea caves develop in structurally different basaltic lavas and pyroclastics. [ABSTRACT FROM AUTHOR]

Marine caves are characterized by wide environmental variability for the interaction between marine and continental processes. Their conditions may be defined as extreme for inhabiting organisms due to the enclosed morphology, lack of light, and scarcity of nutrients. Therefore, it is necessary to identify reliable ecological indicators for describing and assessing environmental conditions in these habitats even more than elsewhere. This review aims to provide the state of art related to the application of benthic foraminifera as proxies in the (paleo)ecological characterization of different habitats of marine caves. Special attention was addressed to a research project focused on Mediterranean marine caves with different characteristics, such as extent, morphology, freshwater influence, salinity, sediment type, oxygenation, and organic matter supply. This review aims to illustrate the reliability of foraminifera as an ecological and paleoecological indicator in these habitats. They respond to various environmental conditions with different assemblages corresponding to a very detailed habitat partitioning. Because marine caves may be considered natural laboratories for environmental variability, the results of these studies may be interpreted in the perspective of the global variability to understand the environmental drivers of future changes in marine systems. [ABSTRACT FROM AUTHOR]

Abstract: Fish assemblages associated with marine caves and rocky cliffs were investigated in the Salento Peninsula (SE Italy, Mediterranean Sea) by using visual census methods. Sampling was done at three sites, each of which included 4 habitat types: the external and the internal portions of caves, and shallow and deep rocky cliffs. 10 and 13 species were found exclusively inside cave habitats (e.g. Corcyrogobius lichtensteini, Thorogobius ephippiatus and Grammonus ater) or in rocky cliffs (e.g. Diplodus annularis, Sarpa salpa, Sparisoma cretense, Spondyliosoma cantharus), respectively. The four habitat types shared 10 species, and the external portions of the caves shared the most species (both with the internal cave portions and the external rocky cliffs). As a general rule, dissimilarity in the fish assemblage structure between habitats was far greater than dissimilarity between sites. Apogon imberbis (mostly associated with caves) and Chromis chromis (typifying rocky cliffs, mainly the deep ones) mostly contributed to dissimilarities between caves and rocky cliffs. Apogon imberbis (mostly associated with internal caves) and Coris julis (mainly associated to external cave portions) contributed strongly to dissimilarities between internal and external cave portions, while C. chromis, Symphodus mediterraneus and C. julis (associated with the deeper cliffs) and Thalassoma pavo (mostly present in shallow cliffs) differentiated deep and shallow cliffs. Diplodus vulgaris, Oblada melanura and Mullus surmuletus showed a marked increase in density during the cold season in the caves. These results show that fish assemblages associated with rocky reefs rich in marine caves (in terms of relative densities, species composition, species richness, exclusive species and presence of juveniles of some valuable species) may be affected by the peculiar ecological conditions within caves, which could provide additional resources for fishes (e.g. food availability, refuge against predators, sand patches within a rocky matrix) compared to rocky reefs without caves. These results suggest that stretches of rocky coasts rich in marine caves should be considered within management/conservation programs (e.g. when establishing Marine Protected Areas). [Copyright &y& Elsevier]

Abstract: A study of inorganic iodine speciation in the waters of seven Croatian coastal caves is described. These are anchialine caves as they are connected hydraulically with Adriatic Sea surface water, with the tide inside the cave rising and falling with that outside, but replenishment of the water is restricted by the karst rock. In effect, the water in the cave probably acts more like a piston, and although moving slightly vertically, has a long residence time compared to a fully-flushing cave. Anchialine environments display a number of unusual features, e.g., a well-developed pycnocline, hypoxia and endemic fauna. Iodate and iodide were determined by differential pulse voltammetry and cathodic stripping square wave voltammetry, respectively. Low iodide concentrations (<10 nM) have been consistently identified in the bottom water of the caves where concentrations of 90–100 nM would ordinarily be expected from intrusion of Eastern Adriatic surface seawater. Where total inorganic iodine concentrations behave conservatively with salinity the loss of the iodide implies oxidation to iodate. As iodide oxidation remains one of the enduring academic problems of the marine iodine system the study of iodine in anchialine caves may help unravel it. Iodate reduction was observed in mid-water, at the halocline, and mechanisms for the reduction involving either respiration or chemolitho-autotrophic bacteria are considered. The respiration mechanism is favoured because of enhanced alkalinity found in the near surface waters of the caves. [Copyright &y& Elsevier]

Abstract: Most of the studies on biological and ecological effects associated with brine discharge into the marine environment are related to the operation of desalination plants, for the production of freshwater. In this study we analysed the biological effects of a brine effluent from a completely different source, produced from the lixiviation of rock salt caves, for the creation of natural gas storage caverns. Lethal and sub-lethal endpoints following exposure to the brine were studied in a range of macrofauna species characteristic of the soft and hard bottom habitats in the vicinity of the discharge area, namely the isopod Eurydice pulchra, the annelids Sabellaria alveolata and Ophelia radiata, the sea-urchin Paracentrotus lividus and the bivalve Mytilus galloprovincialis. In a first series of experiments, brine, with salinity above 300, was diluted in distilled water to a salinity value close to that of the seawater in the discharge area (salinity 36) and, surprisingly, none of the exposed species was able to survive or develop into viable larvae. A second series of experiments exposed the species to brine diluted with seawater, simulating more realistic discharge circumstances. All the tested species at all the measured endpoints (adult survival, larval abnormal development, sperm fertilization success) showed negative biological effects in brine solutes always at a lower salinity than that of a salinity control obtained with concentrated seawater. The sub-lethal experiments with larval development of P. lividus, S. alveolata and M. galloprovincialis, and the fertilization success of P. lividus gave EC50 values for the brine solute with salinity in the range of 40.9–43.5, whereas the EC50 values for the concentrated seawater were in the range of salinity 44.2–49.0. It is hypothesised that differences in the ionic composition of the brine cause the inability of the species to tolerate the exposure to brine. [Copyright &y& Elsevier]

Magnetic resonance sounding (MRS) is a geophysical technique developed for groundwater exploration. This technique can be used for investigating karst aquifers. Generally, the study of a karst requires a 3D field setup and corresponding multichannel data-acquisition instruments. Now only single-channel MRS equipment is available; i.e., the time needed for a 3D MRS field survey is multiplied by a factor of four or five. Where karst caverns are natural hazards, as in the Dead Sea coastal area at Nahal Hever, Israel, even an approximate localization of potentially dangerous zones and a corresponding estimation of the hazard dimensions are useful. We studied numerically the accuracy of MRS estimations of the volume of different 3D targets around Nahal Hever, shifting a 3D target inside the MRS loop and calculating the volume-estimation errors for each target position. The calculations covered targets of different sizes. The size and position of a target being unkhown factors in a field survey, the numerical data were considered as random values to be analyzed statistically. Using a 1D approximation of the MRS solution and assuming a 100- x 100-m² MRS loop, the volume of a 3D target under Nahal Hever conditions is estimated within a ±75% error when the target is smaller than the MRS loop, and within a ±50% error when the target size is about the same as the MRS loop. The lower threshold of karst-cavity detection with MRS is about 6500 m³. For such estimation, only one sounding is required. [ABSTRACT FROM AUTHOR]

Abstract: We measured the δ 18O values of the whole shells of the cavernicolous micro-bivalvia Carditella iejimensis obtained from sediments within a submarine cave (31 m water depth) at Ie Island (Okinawa Island, Japan) in the subtropical Northwest Pacific. Our results show no significant millennial-scale trend in the δ 18O record, implying that both springtime temperature and the δ 18O of sea water at 30 m depth around the Okinawa Islands have been stable for the past 3000 years at values similar to those of today. Moreover, we found one exceptionally light δ 18O value from specimens spanning the past 250 years. The δ 18O-derived temperature represents a departure of 2.1 °C from the average value for the past 250 years, being equal to the departure recorded during unusually high temperatures in the spring of 1998. This finding may imply that such high springtime sea surface temperature has been a rare event over the past 3000 years. [Copyright &y& Elsevier]

Growth, external morphology and reproductive phenology of a southern Adriatic population of Pterocladiella capillacea from a marine cave were investigated. Production of new uprights from creeping axes was limited to late autumn–winter; upright growth in length and branching order increase reached their maxima in late summer. Tetrasporic fronds were dominant from June to September, with a peak in July, while cystocarpic uprights were rather rare and recorded in August only. Two stable, distinct morphotypes occurred in this population at two sampling sites exposed to different daily photon irradiances. Uprights from the more illuminated site were regularly pinnate, with numerous closely packed lateral branches, representing the best-known phenotype of the species; in contrast, uprights from the more shaded inner site had very long and narrow axes, greater intervals between first-order branches and lower branching order. Statistical analysis demonstrated that upright growth in length and branching was significantly different at the two sites; upright biomass in the more illuminated site was generally higher because of the higher orders of branching. [ABSTRACT FROM AUTHOR]

A collection of 32 amphipod species from submarine cave habitats and control sites to the east of Hong Kong Island was made during a joint NHM/SWIMS expedition in October 2002. Three families (Caprellidae, Endevouridae and Kamakidae), nine genera (Monoliropus, Caprella, Paraloiloi, Leptocheirus, Microjassa, Cerapus, Listriella, Ensayara and Birubius) and 12 species (Monoliropus concavimanus sp. nov.; Caprella aff. penantis; Elasmopus sp. A; Ptilohyale aff. barbicornis; Cerapus sp. A; Paraloiloi sp. A; Ensayara bifurcata sp. nov.; Birubius nauarchuncus sp. nov.; Podocerus cluspiclunis sp. nov.; Megaluropus sp. A; Urothoe sp. A (aff. cuspis); and Urothoe aff. spinidigitus) can be added to the amphipod checklist for the South China Sea area. [ABSTRACT FROM AUTHOR]

During October 2002, the benthic communities of Conic Island Cave and the adjacent sea area of Hong Kong were sampled by SCUBA divers. Twenty genera and 21 decapod species were identified with seven species being reported from Hong Kong for the first time. [ABSTRACT FROM AUTHOR]

During sampling of submarine cave and associated habitats in the eastern waters of Hong Kong in October 2002, polychaetes were found to be a significant and diverse component of the epifaunal and the soft-sediment benthic marine fauna. Of the families considered herein, eighteen taxa of polychaetes are identified, including at least five new records for Hong Kong (Harmothoe minuta, Iphione ovata, Sthenelais fusca, Neanthes caudata and Arichlidon hanneloreae), and one new species of Sigambra (Pilargiidae). Notes on the identification of these taxa and closely related taxa reported from Hong Kong waters are provided, along with a key to the genera of Chrysopetalidae of the world. [ABSTRACT FROM AUTHOR]

A new species of pycnogonid, of the genus Pycnogonum, is described from the sandy-mud benthos at 17 m depth in a submarine cave off eastern Hong Kong. It belongs to a limited group of small species which have no auxiliary claws, a barrel-shaped proboscis and a male oviger of seven articles. It is distinct in the disposition of dorsal trunk tubercles: only trunk segment three has a midline tubercle, while lateral process tubercles are present only on the third and fourth segments. [ABSTRACT FROM AUTHOR]

Nematode assemblages from sediments of two submarine caves in subtropical Hong Kong waters were investigated, and compared with those from other local sublittoral sediments. A total of 48 putative nematode species from 44 genera and 18 families were identified from the caves. Species richness of the cave nematode assemblages lay between those of adjacent sandy control sites and muddy control sites. Species diversity of the cave assemblages was much lower than those of the sandy control sites but was comparable with those of local muddy sediment. Nematodes at Conic Island Cave were dominated by non-selective deposit feeders, while at Steep Island Cave most nematodes were omnivores/predators. This is in contrast with the more even composition of trophic guilds at the nearby non-cave sites. Multivariate analyses revealed no clear demarcation of community structure among the cave, non-cave and wreck nematode assemblages, indicating no nematode species association endemic to the cave sediment. Sediment characteristics and water depth are suggested as fundamental in determining nematode community structure and trophic composition in the area investigated. Submarine cave sediment provided a sheltered habitat with limited food resources favourable for non-selective deposit feeders and omnivores/predators. [ABSTRACT FROM AUTHOR]

Two species of barnacles (Cirripedia) have been collected from Conic Island Cave, Hong Kong, at depths of between -11.8 and -18.2 m C.D. These are Armatobalanus quadrivittatus (Darwin) and Tetraclitella pilsbryi (Utinomi). Neither is a cave endemic. Armatobalanus quadrivittatus ranges widely throughout the Indo-West Pacific and T. pilsbryi is restricted to the Sino-Japanese region (the East and South China Seas and waters of southern Japan) although both are typical of hypobiotic niches. Armatobalanus quadrivittatus has not hitherto been recorded from Hong Kong and its occurrence here brings the local total of barnacle species to 60. [ABSTRACT FROM AUTHOR]

The article reports on the species of fish identified from the Conic Island Cave in Hong Kong, China. Diverse species of fish were found during the Hong Kong Marine Caves' Expedition convened in collaboration with the Swire Institute of Marine Science and the Natural History Museum in London. Several fish species were discovered with the aid of a digital camera used by the scuba divers to capture the marine species which are commercially important for food consumption and aquarium trade. Roughly about 17 marine species were identified including Japanese scad, Snapper, and Little tuna.

Three new species of anthurid isopod are described, one each of the genera Caenanthura and Amakusanthura from within or adjacent to Conic Island Cave, eastern Hong Kong, and a new species of Cyathura from the Mai Po Marshes in northwestern Hong Kong. The anthurid isopods of Hong Kong waters are reviewed. In addition, a new arcturid isopod species of the genus Arcturina is described, also from the vicinity of Conic Island Cave. [ABSTRACT FROM AUTHOR]

An investigation of two subtidal caves in the eastern exposed waters of Hong Kong was undertaken in 2002. The geological context and the physical parameters of the cave environments are described. The caves, or zawns, occurring at depths of between -9.3 to -12.4 m C.D. and -1.8 to -18.2 m C.D. at Steep Island and Conic Island, respectively, were probably created at a time of lowered sea levels during the last ice age >19,000 years ago. The caves have subsequently been drowned and each now possesses a floor that is covered in muddy sand. The present paper sets the context for the range of taxonomic and ecological studies undertaken during the 2002 Hong Kong Marine Caves Expedition. [ABSTRACT FROM AUTHOR]

In October 2002, the Hong Kong Marine Caves Expedition was convened jointly by the Swire Institute of Marine Science, The University of Hong Kong and the Natural History Museum, London. The expedition explored the marine cave habitats of Hong Kong and their fauna. This paper describes the diversity of marine cave molluscs collected using SCUBA from two marine caves at Conic Island and Steep Island in the eastern waters of Hong Kong. Twenty, and eight species of shell-bearing epifaunal bivalves and gastropods, respectively, were collected from the ceilings and walls of the two caves. Another 11 infaunal bivalve species were collected from the sediment-filled floors of the caves. Of the species identified, eight are new records for Hong Kong. These are the bivalves Spondylus anacanthus, Hiatella cf. orientalis, Panomya turgida, Nuculana sp., Abra cf. fujitai, Pinguitellina cf. nux, and Lyonsiella cf. parva, and the epitonid gastropod Epitonium bullatum. The epibenthic molluscs recorded during this survey were mostly adults whereas the endobenthic bivalves were all juveniles. Although the above species are recorded from Hong Kong for the first time, they have been identified from non-cave habitats elsewhere. In particular, the often singular presence of juvenile infaunal bivalves in the cave sediments suggests their opportunistic colonization by such species and thus further evidence for a lack of endemicity. That the epibenthic molluscs are non-endemic is probably also because Hong Kong's submarine caves are very modern, that is, Middle Holocene. [ABSTRACT FROM AUTHOR]

In October 2002, staff from the Swire Institute of Marine Science (SWIMS), the University of Hong Kong, and the Natural History Museum (NHM), London, mounted a joint expedition to study submarine caves (zawns) off the eastern coast of Hong Kong, to test hypotheses that they may support either endemic or unusual communities, or they may act as refugia for such taxa. The present paper analyses the sedimentary macroinfaunal communities from that survey. Sampling was by hand-coring undertaken by SCUBA divers. Muddy-sand habitats within two caves were sampled in comparison with four control sites outside the caves, one of heterogeneous muddy sand, one of clean sand and two of fine mud; the samples were sieved across a 0.5 mm mesh. Sedimentary granulometry, water temperature, pH and dissolved oxygen were also measured. The benthic community within the caves showed a higher density and diversity than most of those described from non-cave sediments in Hong Kong waters. The community was distinct from that found at the control sites, partly owing to sediment granulometry differences. Thirty-three species were found only in the caves, some of which are known from elsewhere in non-cave habitats; six species are, to date, only known from these caves. It is concluded that the cave habitat conditions offer a stable and sheltered habitat which allows the development of a distinct community, although not representing an endemic fauna, as well as being a refuge for species under threat from anthropogenic or natural stresses outside the caves. [ABSTRACT FROM AUTHOR]

Sixteen species of ahermatypic scleractinian corals have been collected from two submarine caves in Hong Kong. These are Ballanophyllia eguchii, B. ponderosa, Dendrophyllia arbuscula, D. ehrenbergiana, D. coccinea, D. compressa, D. gracilis, Turbastrea coccinea, T. faulkneri, T. diaphana, T. sibogae, T. turbinata, Cyathellia axillaris, Culicia japonica, C. rubeola and Oulangia stokesiana. Eleven of the species are new records for Hong Kong. This study has thus obtained the most diverse collection of ahermatypic corals from Hong Kong hitherto. None of the corals is a cave endemic, however, all being widely distributed in the Indo-West Pacific. Nevertheless, such cave habitats may be locally important for ahermatypic corals and it is recommended that they be designated as Sites of Special Scientific Interest and possibly receive wider protection under the Marine Parks Ordinance (1995). [ABSTRACT FROM AUTHOR]

Some two hundred taxa have been recorded from Hong Kong's submarine caves. Of these, at least eleven are new to science. The majority of species occurring on the walls and roofs in particular, however, are not cave endemics and have been recorded from other habitats in Hong Kong and elsewhere. Unlike the Tethyan karsted limestone caves of Japan and the Philippines in the Asian region, and elsewhere, Hong Kong's cave fauna is similar to other local sea bed habitats at similar depths, probably because of their modernity. Although the sediments that make up the cave's floors appear more stable (in terms of their faunistic composition), there is evidence that they are periodically infilled and flushed out. This may be either on a seasonal basis or following severe tropical storm and typhoon events. It is therefore likely that the infaunal taxa of the cave's floors are partly sustained by episodic colonization. Notwithstanding the lack of an identifiable endemicity, the caves act as refugia for a number of otherwise rare taxa, for example, the ahermatypic corals Balanophyllia eguchii and Tubastrea falkneri, and fishes gain protection within them from locally intense fishing activities. The caves also appear to contain epifaunal communities that are representative of earlier, undisturbed times and environmental conditions in Hong Kong. It is recommended that (i) the two caves on Conic Island and Steep Island be designated as Sites of Special Scientific Interest; (ii) that other caves be searched for and studied and (iii) more long-term studies be made of their physical environments and the communities they support. [ABSTRACT FROM AUTHOR]

Twenty species of soft corals belonging to the Octocorallia and one species of Ceriantipatharia were collected from two submarine caves in the oceanic southeastern waters of Hong Kong. Of these, 13 octocorals and one black coral were new records for Hong Kong. One new species, Paraminabea hongkongensis sp. nov., is described herein. Sixty octocorals and six ceriantipatharians have now been recorded from Hong Kong, most from open areas of the seabed. That the 14 new records for Hong Kong are from small marine caves highlights the importance of such marine habitats locally. None of the 14 species is a cave endemic, however, all have been recorded from elsewhere in the Indo-West Pacific. Nevertheless, it is recommended that Hong Kong's submarine caves be designated as Sites of Special Scientific Interest and possibly further receive protection under the Marine Parks Ordinance (1995). [ABSTRACT FROM AUTHOR]

Composition and abundance patterns are described for the plankton assemblages in a shallow submarine cave ‘Grotta di Ciolo’, on the Salento Peninsula (Apulia, SE Italy) side of the Otranto Channel, between March 2002 and March 2003. Every 20 days, samples were collected at two sites inside the cave (near to and far from the entrance), and one outside, by towing 50 and 200 μm mesh sized plankton nets at each station for a horizontal distance of 30 m. Also four nocturnal collections were conducted. Temporal and spatial patterns of distribution were described, and multivariate analyses were used to assess trends in community composition. A total of 232 taxa were recognised. The cave plankton appeared more affected by the hyperbenthos than outside plankton. Mysidacea represented the most conspicuous component of the cave plankton, with two species typical in Salento marine caves, Hemimysis margalefi and Siriella jaltensis. Harpacticoida copepods, together with asexual algal propagules, dominated the plankton of the cave numerically, whereas Calanoida and Cyclopoida copepods with mollusc veligers characterised the plankton of the outside sector. While the mysid S. jaltensis was found outside the cave in nocturnal samples, H. margalefi appeared to migrate simply along the axis of the cave, never leaving it during night. The community composition changed seasonally over the 1-year period. There was clear horizontal partitioning of the plankton, with significant differences between the two stations of the cave. Higher water turbulence probably explains the presence of asexual propagules even at the inner station. An explanation of the benthos impoverishment has been proposed as an alternative to the current ‘trophic depletion’ theory. [ABSTRACT FROM AUTHOR]

Cave diving expeditions were conducted in the Golfo di Orosei in June/July 2003 and July 2004. The main site of the exploration was located 500 m north of Cala Sisine ( Fig. 1 ). The cave system of Grotta del Bel Torrente is one of the biggest in Sardegna. To date, a total of more than 2.5 km dry and water-filled passages have been surveyed. A map of the cave was generated as the basis for further investigations. The focus of the biological work is on the diversity of the species and their distribution throughout the cave until 800 m from the entrance. Until 350 m from the entrance a clearly visible halocline is developed between the upper layer (20 °C, salinity about 22) and the underlying water column (22 °C, salinity about 33). A zone of intermediate water salinity and temperature, without halocline, follows over a distance of 100 m. In more than 450 m from the entrance the salinity drops to 1 and temperature is 15 °C. Up to 350 m from the entrance, marine sponges, molluscs, crustaceans, polychaetes, ascidians and fishes were observed. The occurrence of empty tubes of Serpulidae and shells of oysters in this zone may reflect oxygen deficiency. Some fish such as mullet ( Liza sp.) migrate between the fresh and salt water columns. [ABSTRACT FROM AUTHOR]

Several studies have described patterns of distribution and species composition of sessile assemblages from marine caves but few have examined the processes of recruitment and larval settlement in the earlier stages of substrate colonisation. The present study evaluated (i) the distinctness of newly recruited assemblages on the local spatial scale, (ii) how this assemblage distinctness changes over time and (iii) how the recruitment patterns are affected by a different start-time in different positions in the cave. Two sets of 90 baked-clay panels (15 × 15 × 1 cm) were deployed in March (E1) and October 2002 (E2) at three positions in the shallow submarine cave ‘Grotta di Ciolo’ (South-East Italy, Central Mediterranean Sea): entrance (P1) and at 20 m (P2) and 80 m (P3) from the entrance, respectively. Each position was represented by two areas (1.5 × 1.5 m), and three panels from each area were randomly removed after 1, 3, 6, 12 and 24 months. The assemblages of the settled organisms comprised a total of 63 taxa. Different succession patterns were highlighted among assemblages across positions. A recruitment period of 2 years allowed a complete colonisation of panels at P1, where both encrusting algae dominated rocky walls and panels. In contrast, recruitment was very slow at P2 and P3, where the mature benthic community was not replicated on the 2-year panels. Finally, there was a partial convergence towards a common ecological succession in series started at different times. [ABSTRACT FROM AUTHOR]

The sponges Oopsacas minuta (Hexactinellida) and Asbestopluma hypogea (Demospongiae, Cladorhizidae) belong to groups that are typical of deep water, but both species have already been recorded from the shallow water Trois Pépés cave at La Ciotat (Marseille area). We here report on subsequent findings of A. hypogea in two other littoral caves: one at Garmenjak Island in the Middle Adriatic (Croatia), the other at Jarre Island (Marseille, France). The maximum temperatures experienced in situ by these populations are not only significantly higher than those from the deep Mediterranean Sea, but they are also up to 6 °C higher than those reported for the Trois Pépés cave population, up to 23.1 °C in July 2002 for the Garmenjak population and 22.8 °C in August 2004 for the Jarre population (exposures from a few hours to a few days). The average summer temperature inside both caves remains several degrees lower than the outside temperature at the same depth. Long-term survival of A. hypogea populations at the relatively high summer/autumn temperatures in both Jarre cave (4 years monitoring) and Garmenjak cave (5 years monitoring) indicates that the species can successfully colonise such shallow habitats in spite of its presumed deep-water origin. We also report additional cave records of O. minuta in the Adriatic (Croatia): from the marine part of the Živa Voda anchialine cave at Hvar Island, from the marine caves at Iški Mrtovnjak, Lastovo and Fraškerić Islands. The wide distribution of this species in the deep Mediterranean is substantiated by a record on Santa Lucia Bank north of Corsica (303 m) and photographs taken by the submersible Cyana in the Central Tyrrhenian Sea (2912 m, 2845 m) and the Ionian Sea (2447 m). All the findings of these two species in the Mediterranean are reviewed and possible patterns of their colonisation of littoral caves are discussed. [ABSTRACT FROM AUTHOR]

We studied the use of six caves by metamorphosed plethodontid salamanders from 2000-2005 in the Cumberland Plateau of northwestern Georgia. Nine species were observed, the most abundant being, in descending order, Eurycea lucifuga, Plethodon glutinosus, P. petraeus, and E. longicauda. Eurycea lucifuga and P. glutinosus were the only species observed in all six caves. Salamanders used caves seasonally, and all four species were more abundant within caves during seasons with warm, long days. A parsimonious explanation for the observed seasonal pattern of cave use is that salamanders use both cave and surface habitats, moving into caves to avoid hot, dry conditions on the surface. Eurycea lucifuga was most abundant in low-elevation, cold caves. The abundance of P. glutinosus was positively related to cave dimension and secondarily to wall heterogeneity. Species richness was not randomly distributed among caves, but neither was it consistently related to particular variables. Caves into which salamanders crowd during certain seasons represent ideal situations for the testing of hypotheses related to species interactions, both within and among species. [ABSTRACT FROM AUTHOR]

Submarine caves, cavities and niches characterised by H2S elevated concentrations are particularly interesting for their inhabiting microflora as well as for the overall chemical, geological and biological parameters. These ecosystems are usually populated by well adapted living forms, physically distributed following the in situ concentration and gradient of micronutrients, O2 and H2S, and also according to the values of temperature and pH. The biota is primarily characterised by prokaryotes (both autotrophic and heterotrophic) adapted to anoxic and/or microaerophilic condition and capable to form extensive biofilms on the rocky surfaces and even on the bottom sediment. These habitats can be defined as extreme, because the scarcity or absence of solar irradiation, the chemo-physical traits and the fact that specialised prokaryotes are often the only inhabitants. This review is focused on the microbial ecology of marine caves and holes characterised by high levels of hydrogen sulphide. Ecological and geological data are already available but very few insights as far as regard microbiology were achieved in order to describe these fascinating habitats. The autochthonous mesophilic and thermotolerant microorganisms living in these caves may have interesting physiological traits and eventually may lead to potential application in biotechnological processes. [ABSTRACT FROM AUTHOR]

Abstract: Morphological features along the Algarve rocky coast, South Portugal, are identified and described, with an emphasis on shore platforms and notches. The contributions of processes, such as wave attack, chemical weathering and bioerosion, to sculpting the shore platforms are discussed. The preferential localization of shore platforms on sites exposed to waves, and the lack of significant chemical weathering, point to wave erosion as the first-order factor in platform formation, whilst bioerosion/bioprotection, lithology and geological structure determine platform morphological variations. In addition, platforms above the present intertidal zone appear to have a polygenetic evolution, being inherited from former sea-level highstands and currently undergoing chemical weathering. The occurrence of notch features is independent of the degree of exposure to waves, but they mostly occur where the substratum is sand. Hydrostatic pressure appears to be an important factor in the formation of marine caves in the more sheltered sites. [Copyright &y& Elsevier]

Habitat fragmentation and climate change are two major threats on biodiversity. Fragmentation limits the number of patches and their decreased connectivity cannot always maintain populations at dynamic equilibrium. The natural extreme fragmentation of marine cave habitats represents an opportunity to understand how these processes interact. The hypothesis of a low gene flow among populations due to a high level of fragmentation was tested by analysing sequence variation in a fragment of the mitochondrial gene of the cytochrome oxidase subunit I in 170 individuals (23 localities across the NW Mediterranean) of two marine cave-dwelling mysids of the genus Hemimysis. The species Hemimysis margalefi recently replaced its congener Hemimysis speluncola, a species shift that could be related to the warming of the Mediterranean Sea and to differences in their thermal tolerances. There were too few H. speluncola samples to further discuss their genetic structuring, but for H. margalefi, the present study revealed high levels of genetic diversity and genetic structuring, as shown by the eight genetically distinct groups identified. The Croatian group might constitute a sibling species due to a strong divergence (15%). Nevertheless, these groups present reduced but orientated gene flow according to the general circulation in the Mediterranean, and fit a stepping-stone model. At local scale (Marseille area, France), gene flow among caves is dependent on unexpected local hydrodynamic barriers, that determine metapopulation sizes. Through the example of mysid species inhabiting marine caves, the present work confirms the strong influence of habitat disjunction (natural fragmentation) on population structure, and stresses the importance of coastal geomorphological features in inducing complex interactions between the circulation of water masses and the circulation of genes. [ABSTRACT FROM AUTHOR]

During the past 5 decades, the large-sized biota inhabiting dark marine caves has attracted the attention of many marine biologists; in contrast, studies concerning the meiofaunal organisms of these peculiar biotopes remain scanty and mostly with a taxonomic aim. In this study, the nature and abundance of meiofaunal taxa living in a Mediterranean, semi-submerged sea cave was surveyed in relation to distance from the entrance and over two different seasonal periods. Particular attention was paid to the Gastrotricha taxocene. Research was carried out in a cave along the Ionian coast of Apulia (southern Italy), the “Grotta Piccola del Ciolo” which opens for approximately 120 m on the north-eastern side of a shallow fjord and has a bottom blanketed by fine to very fine sand, occasionally rich in detritus. Quantitative samples in four replicates were collected by SCUBA diving, in November 2000 and June 2001, coring the sediment with a hand-held piston corer in three light-free sites (stations 1–3) located at increasing distances from the entrance. At each site, two additional 500-ml sediment samples were collected for an in vivo study of the Gastrotricha. Faunistic analysis found a fairly high meiobenthic diversity, identifying representatives of more than 12 major groups, with total abundances ranging from 656 ind./10 cm2 (10 cm2) in November to 1,069 ind./10 cm2 in June. Station 1, the closest to the entrance invariably hosted the most abundant meiofaunal community (851 ind./10 cm2 in November and 1932 ind./10 cm2 in June), followed by station 2 or 3 depending on the season. While nematodes and harpacticoids appear as the most abundant taxa when the cave is considered as a whole, other taxa may prevail numerically in selected stations, e.g. priapulids, which are the second most abundant taxon at station 1 (30 ind./10 cm2 in November and 83 ind./10 cm2 in June). Although the density of total meiofauna and that of the single groups may not be very high, the cave is interesting by virtue of the peculiarity of the hosted fauna, e.g., species and genera new to science or new to the Mediterranean Sea. Regarding the Gastrotricha, we found 16 species, accounting for 1.3–2.6% of the total meiobenthos (density = 8.4 ind./10 cm2 in November and 27.4 ind./10 cm2 in June). Analysis of the gastrotrich community found, particularly in June, an assemblage of taxa quite different from those found in open habitats, even at the family level; differences that are probably due to the exploitation of different food resources by animals populating the two environments, i.e. algae in the open sea versus bacteria in the caves. Results indicate that for meiofauna, as happens for macrofauna, the marine caves may represent hotspots of biodiversity and endemism; the driving forces at the base of the trophic depletion hypothesis seem to be responsible for structuring the meiofauna community inside the cave. [ABSTRACT FROM AUTHOR]

Using a diver-operated net, Retromysis nura n. gen., n. sp. was sampled in the dimly lit zone of a superficial marine cave on Minorca Island (W. Mediterranean). The females of the new genus are exceptional due to a large sternal plate transversely projecting behind the marsupium. The males are characterized by a mediocaudal lobe on the appendix masculina and by a pair of modified, backwards-oriented setae terminally on the antennular trunk, while the females show normal, smooth, forwards-oriented setae in this position. With this first description, a total of three monotypic genera belonging to the tribe Heteromysini are now known from marine and anchihaline caves in the western Mediterranean. [ABSTRACT FROM AUTHOR]