Anton Brancelj

The epikarst habitat in Slovenia and the description of a new species

Paramorariopsis irenae n. sp. is the second species of the genus, which was described for the first time 15 years ago from a small cave in the southern part of Slovenia. The new species is closely related to Paramorariopsis anae Brancelj, 1991. The main differences are found in the ornamentation of caudal rami, abdominal somites and legs P2–P4, while P5 are very similar. It was initially assumed that the genus represented a member of the community inhabiting wet mosses near the caves entrance. It can now be confirmed that it belongs to a specific community of Copepoda in the epikarst (i.e. part of the unsaturated karst zone). So far two genera are recognised as exclusively epikarstic: Morariopsis Kiefer, 1930 and Paramorariopsis Brancelj, 1991. Both genera were for a long time considered as monospecific with restricted distribution. Intensive sampling of the epikarst zone in Slovenia and Italy revealed that many genera, previously assumed as “rare”, are in fact common, widely distributed, and show a considerable level of specific endemicity. Morphological adaptations of taxa specific for the epikarst are discussed along with detailed discussion on habitat and sampling methods developed for that habitat.

Groundwater Drift as a Tracer for Identifying Sources of Spring Discharge

Groundwater invertebrate drift, collected from the spring outlets at the interface of vadose and phreatic zones, has been examined for its potential for identifying sources of discharge from a karst aquifer. Concurrently, major ion geochemistry, dissolved inorganic carbon (δ13CDIC), particulate organic carbon (δ13CPOC), and naturally occurring stable isotopes of oxygen and tritium (δ18O, 3H) were investigated over a period of 1 year in two outlets, a temporary (TS) and a perennial (PS) spring. A few differences in major ion geochemistry and stable isotope composition were found between the two springs together with moderate seasonal variability. In contrast, invertebrate drift showed clear differences between TS and PS springs in density and composition. Canonical correspondence analysis showed the presence of two distinct groups of samples from TS and PS, with Ca2+ as the only significant explanatory variable for differences in drift composition. Finally, certain species from the drift were found to be useful tracers for distinguishing between the phreatic and the epikarst and vadose zones as the origin of spring water.

Interpretation of epikarstic cave drip water recession curves: a case study from Velika Pasica Cave, central Slovenia

ABSTRACT Recession curves are widely used in hydrological studies and projects, such as in rivers, streams or springs. However, no cave drip water has been analysed with recession curves. In this paper, four cave drips were monitored in the Velika Pasica Cave, in order to discover the water flow and storage properties of the epikarst. Various methods were applied in the recession analysis, combining the hydrological characteristics of the four drips: for the slow water in the epikarst, the matching strip method was the identified as the appropriate model for the drip water recession analysis. According to the recession coefficient k, the water flow in the epikarst was divided into fast flow, intermediate flow and slow flow. The volume of water retained in the reservoir (the epikarst storage) could be presented as a function of its specific recession coefficient. EDITOR D.Koutsoyiannis; ASSOCIATE EDITOR X. Chen

Two new stygobiotic copepod species from the Tibesti area (Northern Chad) and a re-description of Pilocamptus schroederi (van Douwe, 1915)

Between 4th and 18th March 2014, an international group of biologists carried out a hydrobiological expedition to the Ounianga-Tibesti area of northern Chad (Africa). The Tibesti is a desert volcanic area, intersected by the beds of ancient rivers which were active in the Tertiary. In deep canyons there are small water bodies (gueltas/aguelmans), fed by rain and spring water. They are rich in zooplankton, benthos, and even fish, but their groundwater fauna has previously been unknown. Groundwater samples collected in the vicinity of one guelta contained Syncarida, Isopoda, and Copepoda. Among the latter, two new species were recognised, Haplocyclops (H.) henrii sp. nov. and Parastenocaris joi sp. nov., together with a third species, Pilocamptus schroederi (van Douwe, 1915), previously known only from the littoral zone and wet mosses of Lake Victoria. The Tibesti area is thus the third known location of P. schroederi. All these species have a Gondwanaland distribution and are probably relicts of the Tertiary fauna, formerly widespread in the Sahara. Together with descriptions of two new species, a detailed re-description of P. schroederi is presented, along with remarks on their ecology.

The effect of hydrological and hydrochemical parameters on the microdistribution of aquatic fauna in drip water in the Velika Pasica Cave, Central Slovenia

Water quality and quantity significantly affects the aquatic fauna in the epikarst and conversely can also reflect the hydrological environment. Intensive, long-term studies on hydrological and hydrochemical parameters were monitored at 4 permanent dripping sites (VP1–VP4) in the Velika Pasica Cave (Slovenian) over a period from 2006 to 2013 concurrently with aquatic fauna sampling. Multivariate methods were applied to elucidate the relationship between the environmental conditions and the resident aquatic ecosystem. Seven major aquatic taxa were collected from the drips, with Copepoda being the dominant taxa; however, the spatial distribution and composition of these species varied distinctively at the 4 study sites; the drip water from different sites had distinct hydrological and hydrochemical characteristics. The most significant parameters influencing community composition were drip water discharge volume and NO3− ion content. The results indicate that hydrology and hydrochemistry significantly influence the microdistribution of aquatic fauna within the epikarstic aquifer.

Amended diagnosis of the genus Nannodiaptomus (Copepoda, Calanoida), based on redescription of N. phongnhaensis and description of a new species from caves in central Vietnam

Nannodiaptomus phongnhaensis Dang & Ho, 2001, an endemic stygobiotic diaptomid from Vietnam and the type species of the genus Nannodiaptomus Dang & Ho, 2001, is redescribed on the basis of a new material from its type locality: Hang Phong Nha Cave, Quang Binh province, central Vietnam. We also designated a neotype, because the type material has been lost. The diagnosis of the genus is amended, based on the description of the neotype. The taxonomic position of the genus in the subfamily Speodiaptominae is proposed, and its relationships with other genera of this subfamily are discussed. A new cave-dwelling species Nannodiaptomus haii sp. nov., from a cave near the type locality of N. phongnhaensis, is also described and illustrated. The new species differs from the type species of the genus, among other things, by the structure of males left swimming leg 5, where the inner margin of the apical process and the sub-terminal seta on the swimming leg 5 Exp-2 have small serrated membranes, but these bear 3-4 distinct denticular protrusions in N. phongnhaensis.

A new blind groundwater-dwelling genus of the Cladocera (Crustacea: Branchiopoda) from the Korean Peninsula

Groundwater-dwelling Cladocera are to date known only from the caves and hyporheic zones of the rivers in Europe (Belgium, England, France, Bosnia and Herzegovina, Macedonia, Slovenia, Spain), Turkey (European part) and Arabian Peninsula (Yemen). All these animals belong to the subfamily Aloninae Dybowski & Grochowski of the family Chydoridae Dybowski & Grochowski (Cladocera: Anomopoda). Examination of some samples collected by our colleagues - experts in Copepoda, Bathynellidae and Amphipoda-in South Korea led us to discovery of a new stygobiotic alonine genus, which is also the first record of a groundwater-dwelling cladoceran in Asia. Aims of this paper are: (1) to describe Korealona gen. nov., represented by two species, Korealona karanovici gen. nov., sp. nov. found in three different localities, and K. choi sp. nov., also found in three different localities; and (2) to discuss its differences from other genera of this subfamily and possible phylogenetic position of this genus among the aloninse. Distribution ranges of two species of Korealona gen. nov. are not unequivocally associated with present-day main river basins in Korea, but more sampling efforts are needed for final conclusions on their distribution ranges in Korea and closest countries and understanding of the genus evolutionary history.

Spatiotemporal heterogeneity of actual and potential respiration in two contrasting floodplains

Floodplains are vital components of river ecosystems and play an important role in carbon cycling and storage at catchment and global scales. For efficient river management and conservation, it is critical to understand the functional role of spatiotemporally complex and dynamic habitat mosaics of river floodplains. Unfortunately, the fundamental understanding of mineralization and carbon flux patterns across complex floodplains is still fragmentary. In this study, respiratory potential (i.e., electron transport system activity – ETSA) was quantified seasonally across different aquatic and terrestrial habitats (wetted channels, gravel bars, islands, riparian forests and grasslands) of two Alpine floodplains differing in climate, altitude, discharge, flow alteration intensity and land use (Soca – natural flow regime, 12% grassland area; Urbach – mean annual discharge reduction by 30% due to water abstraction, 69% grassland area). In situ respiration (R) was measured and ETSA/R ratios calculated to examine differences in exploitation intensity of the overall respiratory capacity among floodplain habitats and seasons. ETSA and R provided potential and actual estimates, respectively, of organic matter mineralization in the different floodplain habitats. Hierarchical linear regression across habitat types showed organic matter, grain sizes 8 mm were also highly important for the Soca floodplain. The combination of ETSA and R measurements conducted in contrasting floodplains increased our understanding of the relationships between floodplain habitat heterogeneity, organic matter mineralization and human impacts; i.e., structural-functional linkages in floodplains. These data are integral towards predicting changes in floodplain function in response to environmental alterations from increasing human pressures and environmental change.

A new subterranean Maraenobiotus (Crustacea: Copepoda) from Slovenia challenges the concept of polymorphic and widely distributed harpacticoids

Maraenobiotus slovenicus sp. nov. is described from subterranean waters of a very cold, temporary karstic spring in the vicinity of Velika Pasica cave, central Slovenia. A detailed examination of numerous specimens reveals a low level of morphological variability in this population. Morphological characters traditionally used in the genus Maraenobiotus Mrázek, 1893 would identify our population as a subspecies of the polymorphic and widely distributed M. vejdovskyi Mrázek, 1893. This species was reported from the Palearctic, with at least six accepted subspecies, some of which have been reported in sympatry or parapatry, sometimes even without any apparent niche partitioning. One of these subspecies, M. vejdovskyi truncatus Gurney, 1932, originally described from the UK and later on also reported from Italy and Japan, shares with our population the extremely reduced female principal caudal setae. However, a closer examination of the caudal armature and other characters reveals significant differences between these disjunct populations. We propose a hypothesis of distinct species within the M. vejdovskyi-complex, and critically review all recognized and some unrecognized morphotypes and subspecies. As a result, three new species names are proposed for previously reported populations from Italy and Japan: Maraenobiotus galassiae sp. nov.; M. isidai sp. nov.; and M. pescei sp. nov. Four subspecies of M. vejdovskyi are now elevated to the full specific rank: M. anglicus Gurney, 1932; M. arctica Löffler; M. tenuispina Roy; and M. truncatus Gurney, 1932. This hypothesis remains to be tested using molecular (and other) tools, but can serve as a viable alternative to the concept of polymorphic and widely distributed freshwater harpacticoids. http://zoobank.org/urn:lsid:zoobank.org:pub:92302CF9-21BA-4454-A3DD-337BB7152DCE