Inverted, ’parallel’ accretion of organic material in the cave Setergrotta, Rana, northern Norway: a case study

The occurrence of an upside-down parallel accretion of organic gyttja, about 10 cm in thickness is reported from the ceiling of an overflow passage in Setergrotta cave, Mo-i-Rana, northern Norway. The deposition process depended on seasonal flooding, was 14C dated back to c. 6500 cal. BC (7645 ± 115 BP). Two pollen diagrams are presented, one from the accretion and one of a nearby minerogenic cave floor deposit. In the accretion sequence, pollen of spruce (Picea abies) was found only in the youngest parts and corresponds to what is known from vegetation historical studies in the region. No significant signals of neither of known vegetation changes caused by climate nor human impact are found in the parallel accretion, contrary to the floor deposit. One of them indicates a marked deforestation dated to about 790 cal. BC in the catchment area for the cave pollen/water supply.Key words: Pollen analysis, 14C date, inverted parallel cave accretion.Obrnjene ‘paralelne’ akrecije organskega materiala v Jami Setergotta, Rana, severna Norveška: študijski primerV članku poročamo o obrnjenih, do 10 cm debelih, paralelnih akrecijah organskega sedimenta (gyttja) v prelivnem rovu jame Settergrotta, Moi-i-Rana, severna Norveška. Odlaganje tega sedimenta je bilo vezano na sezonsko poplavljanje rova. 14C datacije so določili največjo starost 6500 cal. BC (7645 ± 115 BP). Primerjamo tudi pelodna diagrama iz akrecije z diagramom minerogenih sedimentov na jamskih tleh. V zaporedju akrecije smo pelode smreke (Picea abies) našli le v najmlajšem delu, kar ustreza ugotovitvam zgodovinskih študij vegetacije v regiji. V akrecijah nismo našli nobenih pomembnih znakov vegetacijskih sprememb, ki bi jih povzročile klimatske spremembe ali človek. Drugače je v minerogenem sedimentu na jamskih tleh, kjer pelodna analiza kaže na deforestacijo v času 790 cal. BC v zbirnem območju peloda.Ključne besede: Pelodna analiza, 14C datiranje, obrnjene paralelne akrecije

Karstic aquifers – simple or hybrid systems? Thermal stories from Maaras cave, Greece

Karst systems, such as caves, provide a unique opportunity to study the groundwater from the inside in contrast to spring studies, where hydrographs, chemographs, and thermographs show an integrated signal from the entire catchment and aquifer. Studies from karst springs show that recharge and conduit characteristics significantly influence how the temperature signal is transmitted and thus could inform on the structure of underground flow paths. Here, we present monitoring temperature data from a two-year-long study of a 10 km long river cave, Maaras, in northern Greece. Our data from five measuring stations along the cave stream show how different flow paths transform the temperature signal. The catchment area consists of a polje impacting the recharge conditions that change seasonally from diffuse to concentrated. Diffuse recharge stabilizes the temperature regardless of the conduit conditions. However, temperature fluctuations occur on four different time scales: seasonal, event-based, diurnal, and hourly, indicating different passage conditions. Interaction between the cave stream and the in-cave porous aquifer in the clastic sediments strongly impacts the alteration of the thermal signal through the cave: temperature fluctuations are damped, and the temperature is raised.publishedVersio

Nutrient-limited subarctic caves harbour more diverse and complex bacterial communities than their surface soil

Background: Subarctic regions are particularly vulnerable to climate change, yet little is known about nutrient availability and biodiversity of their cave ecosystems. Such knowledge is crucial for predicting the vulnerability of these ecosystems to consequences of climate change. Thus, to improve our understanding of life in these habitats, we characterized environmental variables, as well as bacterial and invertebrate communities of six subarctic caves in Northern Norway. Results: Only a minuscule diversity of surface-adapted invertebrates were found in these caves. However, the bacte‑ rial communities in caves were compositionally diferent, more diverse and more complex than the nutrient-richer surface soil. Cave soil microbiomes were less variable between caves than between surface communities in the same area, suggesting that the stable cave environments with tougher conditions drive the uniform microbial communi‑ ties. We also observed only a small proportion of cave bacterial genera originating from the surface, indicating unique cave-adapted microbial communities. Increased diversity within caves may stem from higher niche specialization and levels of interdependencies for nutrient cycling among bacterial taxa in these oligotrophic environments. Conclusions: Taken together this suggest that environmental changes, e.g., faster melting of snow as a result of global warming that could alter nutrient infux, can have a detrimental impact on interactions and dependencies of these complex communities. This comparative exploration of cave and surface microbiomes also lays the founda‑ tion to further investigate the long-term environmental variables that shape the biodiversity of these vulnerable ecosystems.info:eu-repo/semantics/publishedVersio

Monitoring and risk assessment for groundwater sources in rural communities of Romania (GROUNDWATERISK)

In the past 100 years, a decreasing rainfall trend has been recorded on Romanian territory, a trend that continues today. Therefore, realistic estimation of the groundwater resources is crucial, especially for the rural communities lacking the economic power to use alternative sources of drinking water. The groundwater sources used by rural communities in Romania generally originate directly from caves, wells or springs with no proper evaluation of the water quality. Groundwater is exposed to different pollutants, as bats' guano in caves, fertilizers in agricultural areas or livestock (cattle, sheep, goats, etc.) farms on the surface. On the other hand, the water extracted directly from inside the caves is affecting groundwater ecosystems, highly vulnerable to any human impact and neglected by European legislation so far. The project aims to monitor, during two consecutive years, groundwater sources with different degrees of above- and underground pollution, from different regions of Romania. To achieve the goals of the project, a multidisciplinary monitoring strategy that will include measurements of hydrological, physico-chemical and biological (microbiology and aquatic invertebrates’ assessment) parameters alongside the quantification of radon and stable isotopes, rainfall or possible inflows of water. The specific outcomes of this project are: i) to test, develop and validate a new, more rapid and efficient method for monitoring and risk assessment of groundwater sources – and not only – by using molecular techniques, and propose this method to the water agencies in Romania; ii) to propose for Romanian authorities to implement a harmonized coherent methodology to measure radon concentration in water, as a consequence of EURATOM Directive; and iii) to educate local communities that are using groundwater as source for drinking water and raise young people’s awareness on the benefits of ecosystem services provided by the groundwater

Monitoring and risk assessment for groundwater sources in rural communities of Romania (GROUNDWATERISK)

In the past 100 years, a decreasing rainfall trend has been recorded on Romanian territory, a trend that continues today. Therefore, realistic estimation of the groundwater resources is crucial, especially for the rural communities lacking the economic power to use alternative sources of drinking water. The groundwater sources used by rural communities in Romania generally originate directly from caves, wells or springs with no proper evaluation of the water quality. Groundwater is exposed to different pollutants, as bats' guano in caves, fertilizers in agricultural areas or livestock (cattle, sheep, goats, etc.) farms on the surface. On the other hand, the water extracted directly from inside the caves is affecting groundwater ecosystems, highly vulnerable to any human impact and neglected by European legislation so far. The project aims to monitor, during two consecutive years, groundwater sources with different degrees of above- and underground pollution, from different regions of Romania. To achieve the goals of the project, a multidisciplinary monitoring strategy that will include measurements of hydrological, physico-chemical and biological (microbiology and aquatic invertebrates’ assessment) parameters alongside the quantification of radon and stable isotopes, rainfall or possible inflows of water. The specific outcomes of this project are: i) to test, develop and validate a new, more rapid and efficient method for monitoring and risk assessment of groundwater sources – and not only – by using molecular techniques, and propose this method to the water agencies in Romania; ii) to propose for Romanian authorities to implement a harmonized coherent methodology to measure radon concentration in water, as a consequence of EURATOM Directive; and iii) to educate local communities that are using groundwater as source for drinking water and raise young people’s awareness on the benefits of ecosystem services provided by the groundwater

Nutrient‑limited subarctic caves harbour more diverse and complex bacterial communities than their surface soil

Background Subarctic regions are particularly vulnerable to climate change, yet little is known about nutrient availability and biodiversity of their cave ecosystems. Such knowledge is crucial for predicting the vulnerability of these ecosystems to consequences of climate change. Thus, to improve our understanding of life in these habitats, we characterized environmental variables, as well as bacterial and invertebrate communities of six subarctic caves in Northern Norway. Results Only a minuscule diversity of surface-adapted invertebrates were found in these caves. However, the bacterial communities in caves were compositionally different, more diverse and more complex than the nutrient-richer surface soil. Cave soil microbiomes were less variable between caves than between surface communities in the same area, suggesting that the stable cave environments with tougher conditions drive the uniform microbial communities. We also observed only a small proportion of cave bacterial genera originating from the surface, indicating unique cave-adapted microbial communities. Increased diversity within caves may stem from higher niche specialization and levels of interdependencies for nutrient cycling among bacterial taxa in these oligotrophic environments. Conclusions Taken together this suggest that environmental changes, e.g., faster melting of snow as a result of global warming that could alter nutrient influx, can have a detrimental impact on interactions and dependencies of these complex communities. This comparative exploration of cave and surface microbiomes also lays the foundation to further investigate the long-term environmental variables that shape the biodiversity of these vulnerable ecosystems

Global karst springs hydrograph dataset for research and management of the world’s fastest-flowing groundwater

(IF 6.44; Q1)International audienceKarst aquifers provide drinking water for 10% of the world’s population, support agriculture, groundwater-dependent activities, and ecosystems. These aquifers are characterised by complex groundwater-flow systems, hence, they are extremely vulnerable and protecting them requires an in-depth understanding of the systems. Poor data accessibility has limited advances in karst research and realistic representation of karst processes in large-scale hydrological studies. In this study, we present World Karst Spring hydrograph (WoKaS) database, a community-wide effort to improve data accessibility. WoKaS is the first global karst springs discharge database with over 400 spring observations collected from articles, hydrological databases and researchers. The dataset’s coverage compares to the global distribution of carbonate rocks with some bias towards the latitudes of more developed countries. WoKaS database will ensure easy access to a large-sample of good quality datasets suitable for a wide range of applications: comparative studies, trend analysis and model evaluation. This database will largely contribute to research advancement in karst hydrology, supports karst groundwater management, and promotes international and interdisciplinary collaborations