Romanian Caves Research Articles

Is the gut microbiome involved in adaptation of beetles to caves?

Cave beetles are endemic to one or few caves and live in a stable subterranean microclimate and permanent darkness. However, not much is known about the food sources of cave beetles and the share of autotrophic sources in their diet. Seven cave beetles were sampled seasonally from five Romanian caves together with a sampling of sediments and climatic measurements. Gut was extracted from the sampled specimens, and Illumina's 16S amplicon-based metagenomics sequencing protocol was applied to identify the gut microbiome. About 50% of the most abundant bacteria genera in the studied sediments are unknown taxa. The core elements of the sediments' microbiome were wb1-P19, Pseudomonas, and Lysobacter, all producers and decomposers of organic matter. Only Acinetobacter was shared for sediments and all cave beetles. The core bacteria in the gut of Leiodidae beetles of all five species were Vagococcus, Dysgonomonas, Candidatus Soleaferrea, and two unknown phylotypes. The cave Carabidae gut was dominated by Carnobacterium in one species and Enhydrobacter in the other, showing different food regimes within the Duvalius genus. Vagococcus was present in the gut microbiome of Leptodirini and Duvalius, a genus which might be involved in adaptation to life in caves, where food is scarce and autochthonous productivity is low. Higher body weight in cave beetles is another helpful strategy to cope with an infrequent food supply, as demonstrated by the presence of obesity-related gut microbiota representatives, Lactococcus and Serratia.

The Gram-Negative Bacilli Isolated from Caves-Sphingomonas paucimobilis and Hafnia alvei and a Review of Their Involvement in Human Infections.

The opportunistic infections with Gram-negative bacilli are frequently reported. The clinical studies are focused on the course of human infectious and very often the source of infection remain unclear. We aim to see if the Gram-negative bacilli isolated from a non-contaminated environment—the caves—are reported in human infections. Eleven samples were collected from six Romanian caves. We used the standard procedure used in our clinical laboratory for bacterial identification and for antibiotic susceptibility testing of the cave isolates. Out of the 14 bacterial strains, three isolates are Gram-negative bacilli—one isolate belong to Hafnia alvei and two strains belong to Sphingomonas paucimobilis. We screened for the published studies—full-text original articles or review articles—that reported human infections with S. paucimobilis and H. alvei. Data sources—PubMed and Cochrane library. We retrieved 447 cases from 49 references—262 cases (58.61%) are S. paucimobilis infections and 185 cases (41.39%) are H. alvei infections. The types of infections are diverse but there are some infections more frequent; there are 116 cases (44.27%) and many infections of the bloodstream with S. paucimobilius (116 cases) and 121 cases (65.41%) are urinary tract infections with H. alvei. The acquired source of the bloodstream infections is reported for 93 of S. paucimobilis bloodstream infections—50 cases (43%) are hospital-acquired, and 40 cases (37%) are community-acquired. Most of the infections are reported in patients with different underlying conditions. There are 80 cases (17.9%) are reported of previously healthy persons. Out of the 72 cases of pediatric infections, 62 cases (86.11%) are caused by S. paucimobilis. There are ten death casualties—three are H. alvei infections, and seven are S. paucimobilis infections.

The occurence of non-obligate cave dwelling beetles (Insecta, Coleoptera) in the biospeleological provinces of Romania: A faunal and zoogeographic analysis

Beside 143 specialized (obligate) and other 85 non-obligate cave dwelling species of Coleoptera (also named troglobitic species), previously inventoried by us in the Romanian fauna, in this article we present a list of 156 of non-obligate cave dwelling species which occur in different associations in the Romanian caves, for the first time grouped on biospeleological provinces and zones. In the context of the new studies which showed that the “non-obligate” cave dwelling species do not occur randomly in the caves, but having a proved selectivity for caves, this study is focused on biogeographical aspects of non-specialized cave dwelling species.

Monitoring Human Impact in Show Caves. A Study of Four Romanian Caves

(1) Background: Show caves are unique natural attractions and touristic traffic can trigger their degradation within a short time. There are no universal solutions to counter the effects of the touristic impact upon the cave environment and both protection protocols and management plans have to be established on a case-by-case basis. (2) Methods: The study includes four show caves from the Romanian Carpathians, where monitoring of the number of visitors, paralleled by the monitoring of the main physicochemical parameters of the air and water (CO2, temperature, humidity, drip rate, conductivity, and pH) was implemented. (3) Results and Conclusions: The results of the study have: established a set of basic principles to be enforced by the management of show caves and issued a set of preventive measures and instructions to be followed by the personnel and stakeholders of the caves.

Database of Romanian cave invertebrates with a Red List of cave species and a list of hotspot/coldspot caves.

BackgroundThe increasing human impact in Romanian caves raises the urgency of publishing a correct database of the strictly-adapted cave fauna. Previous attempts at indexing cave fauna and classifying caves by using their fauna opened many questions regarding the use of an incomplete list of cave species and mixed lists of troglobionts/stygobionts with troglophiles/stygophiles for ranking caves with priority for protection. It has also become obvious that there is a need to publish a list of Romanian cave species that are under threat. Cave species in Romania (and elsewhere) are endemic on small ranges, are unique and must be considered as important units for conservation. A cave must be equally protected if it has one or more rare and strictly endemic cave species. Although not exhaustive, we here provide the first checklist of Romanian troglobionts/stygobionts developed in the framework of the DARKFOOD and GROUNDWATERISK projects, coordinated by the “Emil Racovita” Institute of Speleology, Cluj-Napoca, Romania. The GIS application was used to complement the checklist of cave species with data on caves and surface environments above the caves. Until complete data on species diversity and population sizes are made available for each cave, measures of conservation can be implemented, based on the presence/absence of cave species, while classifications of caves for protection, based on the number of species, must be avoided. We also propose a list of Romanian caves with fauna that are under threat and a tentative Red List of Romanian troglobiont/stygobionts.New informationThis is the first database with identified troglobiont and stygobiont species of Romania, with a critical analysis of their distribution inside the country. A list of caves that need protection for their rare and unique species and a tentative Red List of Romanian cave fauna are also added. A total of 173 species were identified, of which 77 troglobionts and 96 stygobionts are currently registered in 366 caves. The database is divided into two parts, one part with a list of troglobionts, their revised systematic position, cave name, cave code and geographic region; and the second part with the same information on stygobionts. The database represents the contribution of many active researchers, who are the authors of this paper and of review publications of many other authors of the "Emil Racoviță" Institute of Speleology.

Environmental correlates of community structure in springtails (Collembola) from Romanian caves

Environmental correlates of community structure in springtails (Collembola) from Romanian caves

Radon levels in Romanian caves: an occupational exposure survey.

A comprehensive radon survey has been carried out in seven caves located in the western half of Romania's most significant karst regions. Touristic and non-touristic caves were investigated with the aim to provide a reliable distribution of their radon levels and evaluate the occupational exposure and associated effective doses. Radon gas concentrations were measured with long-term diffusion-type detectors during two consecutive seasons (warm and cold). All investigated caves exceed the European Union reference level of radon gas at workplaces (300Bq/m3). The radon concentration in these caves ranges between 53 and 2866Bq/m3, reflecting particular cave topography, season-related cave ventilation, and complex tectonic and geological settings surrounding each location. Relatively homogeneous high radon levels occur in all investigated touristic caves and in Tăuşoare and Vântului along their main galleries. Except for Muierii, in all the other caves radon levels are higher during the warm season, compared to the cold one. This suggests that natural cave ventilation largely controls the underground accumulation of radon. The results reported here reveal that the occupational exposure in Urşilor, Vadu Crişului, Tăuşoare, Vântului, and Muierii caves needs to be carefully monitored. The effective doses to workers vary between an average of 0.25 and 4.39mSv/year depending on the measuring season. The highest values were recorded in show caves, ranging from 1.15 to 6.15mSv/year, well above the European recommended limit, thus posing a potential health hazard upon cave guides, cavers, and scientists.

Food sources of selected terrestrial cave arthropods

As caves represent an extreme biotope with limited food sources, one might expect cave animal communities to exhibit low feeding specialization and to consume generally whatever organic matter is available. To test this hypothesis, we studied the feeding habits of several arthropod species in Slovakian and Romanian caves. A microanatomical approach utilizing histological methods was selected for this study. While saprophagous animals dominated, our study revealed variability within this nutritional group. Preferences ranged from fungal propagules (for the millipede Trachysphaera costata) to bacteria on bat guano (for the oribatid mite Pantelozetes cavaticus) and to cyanobacteria (for the microwhip scorpion Eukoenenia spelaea). The terrestrial isopod Mesoniscus graniger consumed a mixture of organic and inorganic substrates with plant material in various caves. These findings confirm an adaptability and phenoplasticity and, hence, a variability of characteristics developing under the pressure of extreme environmental factors.

Ecophysiological groups of bacteria from cave sediments as potential indicators of paleoclimate

Six bacterial ecophysiological groups from Pleistocene sediment samples collected from two Romanian caves were identified and evaluated for their potential contribution to the interpretation of paleoclimate. Denitrifiers and nitrite oxidizers were present in the culture plates of all samples, the ammonia oxidizers were absent, and the iron-reducers were confirmed solely in the deepest sample of one of the caves. The aerobic mesophilic heterotrophs were much less abundant in sediments with high clay content, while the ammonifiers were positively correlated to the organic matter content measured in the sediments. In both caves optically stimulated luminescence (OSL) dating, geochemical, sedimentological and grain size analyses were performed and results were correlated to the different groups of bacteria. Results point to the importance of surface conditions during the time of sediment inflow inside the caves, although the bacterial communities have continuously been shaped since deposition. The present study aims to connect features of the paleoclimate with preliminary data on bacteria from old cave sediments.

Mineralogical data on bat guano deposits from three Romanian caves

Mineralogical studies performed on crusts, nodules and earthy masses from the Romanian caves Gaura cu Muscă, Gaura Haiducească and Peștera Zidită have revealed the presence of three different phosphate associations. The minerals have been identified by means of X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Five phosphates have been identified in the samples, with hydroxylapatite the only common mineral in all the three caves. Brushite, taranakite, leucophosphite and variscite are the other phosphates identified. Associated minerals include gypsum, calcite, quartz and illite-group minerals. Aside from differences in the lithology, the occurrences of the different phosphate minerals indicate variable pH and humidity conditions near or within the guano accumulations.

Assessing copepod (Crustacea: Copepoda) species richness at different spatial scales in northwestern Romanian caves

The aim of the present study was to assess copepod species richness in groundwater habitats from the Pădurea Craiului Mountains, Transylvania (northwestern Romania). Five species richness estimators (one asymptotic, based on species accumulation curves, and four non-parametric) were compared by testing their performances in estimating copepod species richness at three hierarchical spatial scales: cave, hydrographic basin, and karstic massif. Both epigean and hypogean species were taken in account. Two data sets were used in computing copepod species richness: 1. samples collected continuously during one year (dripping water) and seven months (pools) from five caves, and 2. samples collected from pools in twelve additional caves (data gathered from literature). Differences in copepod species richness among caves and hydrographic basins suggest that local environmental features are important in determining local species richness trends.

Biodiversity and Ecology of Fauna in Percolating Water in Selected Slovenian and Romanian Caves

Biodiversity and ecology of fauna in percolating water from Slovenian and Romanian caves was studied. Research focused on unravelling the community structure of epikarst fauna, which is carried away by the trickles of percolating water from the epikarst and vadose zones. The major part of the fauna found in percolating water is represented by copepods. This fauna, originating in the epikarst, was analysed and by means of the systematic sampling and observation the same groups of animals were found in Slovenian and Romanian caves. Differences among caves and sampling points indicate that epikarst is a heterogenous habitat. Relationship between faunal richness and the physical characteristics of the water was found. Correlation between surface geomorphology and fauna in percolating water was statistically significant in the Postojna cave system.

A check-list of the harvestmen (Opilionida) from the Romanian caves

A check-list of Opilionida species found until now in Romanian caves is presented. This survey is completed by a list of 182 caves from which the analyzed species were collected.

Contribution à l'étude de certains Lithobiidae (Chilopoda) des grottes de Roumanie

This paper comprises the ecological and zoogeographical data of 21 systematic units of Lithobiidae coming from 100 Romanian caves (Transylvania, Banat, Oltenie and Dobroudja). Initially the author describes in a summarising way the provenance of the studied material, after which he exposes for every species the results of observations carried out by several authors and by himself. Finally he formulates the conclusions concerning ecology and biogeography resulting from his observations. These data are summarised in a synoptic table in which three species can be considered troglobionts, two of which are blind; these are Harpolithobius oltenicus Negrea; Lithobius decapolitus Matic, Negrea et Prunescu; Lithobius daeicus Matic; The other 18 species found are 5 troglophiles, 12 sub-troglophiles and 1 trogloxene.