Environmental DNA simultaneously informs hydrological and biodiversity characterization of an Alpine catchment

Alpine streams are particularly valuable for downstream water resources and of high ecological relevance, however a detailed understanding of water storage and release in such heterogeneous environments is still often lacking. Observations of naturally occurring tracers, such as stable isotopes of water or electrical conductivity, are frequently used to track and explain hydrological patterns and processes. Importantly, some of these hydrological processes also create microhabitat variations in Alpine aquatic systems, each inhabited by characteristic organismal communities. The inclusion of such ecological diversity in a hydrologic assessment of an Alpine system may improve our understanding of hydrologic flows while also delivering biological information. Recently, the application of environmental DNA (eDNA) to assess biological diversity in water and connected habitats has gained popularity in the field of aquatic ecology. A few of these studies have started to link aquatic diversity with hydrologic processes, but hitherto never in an Alpine system. Here, we collected water from an Alpine catchment in Switzerland and compared the genetic information of eukaryotic organisms conveyed by eDNA with the hydrologic information conveyed by naturally-occurring, hydrologic tracers. Between March and September 2017, we sampled water at multiple time points at 10 sites distributed over the 13.4 km$^2$ Vallon de Nant catchment (Switzerland). The sites corresponded to three different water types and habitats, namely low flow or ephemeral tributaries, groundwater fed springs, and the main channel receiving water from both previous mentioned water types

The Variation in Genetic Material of a High Alpine Catchment Reveals (Sub) Surface Exchange

In the past years, it has been proposed that stream networks can accumulate genetic material over a given area. Accordingly, a sample of environmental DNA (eDNA) from streamflow at the outlet of a catchment can be used as an indicator of the upstream biodiversity. eDNA’s use in ecological studies is becoming more and more common and it seems reasonable to assume that eDNA might also offer a powerful tool as a hydrologic tracer. However, the original ecological proposition largely simplifies the complexity of any seasonal, diurnal, or spatial variation according to hydrologic flow paths and processes. From a hydrological perspective, this shortcoming is particularly problematic in Alpine headwater catchments, where the combination of snowmelt-dominated summer flow and particularly high climatic and geomorphologic heterogeneity results in hydrologic flow paths that are especially dynamic in space and time. We were interested to see if on one hand, eDNA could teach us something new about hydrologic (subsurface) flow paths, and on the other hand, if biodiversity assessment should consider hydrologic variation in detail. To do so, we sampled natural occurring eDNA at 11 points distributed over the 13.4 km2, intensively monitored Vallon de Nant (1189-3051 m. a.s.l., Switzerland) between March and September 2017. We chose points corresponding to three different potential microhabitats and flow regimes (main channel, tributary, and spring) likely both inhabited by characteristic organismal communities and of interest for identifying hydrologic flow paths. We found that at moments when streamflow was increasing rapidly, biological richness in upstream points in the main channel and in tributaries was highest contrary to springs, where richness was higher when electrical conductivity was highest. Thus, the main conclusion from our work is that elevated richness corresponds to moments in time when multiple mechanisms transport additional, probably terrestrial, DNA into water storage or flow compartments. These mechanisms could include overbank flow, stream network expansion, and hyporheic exchange. Our data demonstrates that biodiversity assessments using eDNA do need to consider hydrologic processes and shows that there is a potential future for eDNA among hydrologic tracers. We will give recommendations in this talk about how to sample eDNA to answer hydrologic questions

Environmental DNA simultaneously informs hydrological and biodiversity characterization of an Alpine catchment

Alpine streams are particularly valuable for downstream water resources and of high ecological relevance, however a detailed understanding of water storage and release in such heterogeneous environments is still often lacking. Observations of naturally occurring tracers, such as stable isotopes of water or electrical conductivity, are frequently used to track and explain hydrological patterns and processes. Importantly, some of these hydrological processes also create microhabitat variations in Alpine aquatic systems, each inhabited by characteristic organismal communities. The inclusion of such ecological diversity in a hydrologic assessment of an Alpine system may improve our understanding of hydrologic flows while also delivering biological information. Recently, the application of environmental DNA (eDNA) to assess biological diversity in water and connected habitats has gained popularity in the field of aquatic ecology. A few of these studies have started to link aquatic diversity with hydrologic processes, but hitherto never in an Alpine system. Here, we collected water from an Alpine catchment in Switzerland and compared the genetic information of eukaryotic organisms conveyed by eDNA with the hydrologic information conveyed by naturally-occurring, hydrologic tracers. Between March and September 2017, we sampled water at multiple time points at 10 sites distributed over the 13.4 km$^2$ Vallon de Nant catchment (Switzerland). The sites corresponded to three different water types and habitats, namely low flow or ephemeral tributaries, groundwater fed springs, and the main channel receiving water from both previous mentioned water types

Niyazi Bey, Ahmed

Alpine streams are particularly valuable for downstream water resources and of high ecological relevance, however a detailed understanding of water storage and release in such heterogeneous environments is still often lacking. Observations of naturally occurring tracers, such as stable isotopes of water or electrical conductivity, are frequently used to track and explain hydrological patterns and processes. Importantly, some of these hydrological processes also create microhabitat variations in Alpine aquatic systems, each inhabited by characteristic organismal communities. The inclusion of such ecological diversity in a hydrologic assessment of an Alpine system may improve our understanding of hydrologic flows while also delivering biological information. Recently, the application of environmental DNA (eDNA) to assess biological diversity in water and connected habitats has gained popularity in the field of aquatic ecology. A few of these studies have started to link aquatic diversity with hydrologic processes, but hitherto never in an Alpine system. Here, we collected water from an Alpine catchment in Switzerland and compared the genetic information of eukaryotic organisms conveyed by eDNA with the hydrologic information conveyed by naturally-occurring, hydrologic tracers. Between March and September 2017, we sampled water at multiple time points at 10 sites distributed over the 13.4 km2 Vallon de Nant catchment (Switzerland). The sites corresponded to three different water types and habitats, namely low flow or ephemeral tributaries, groundwater fed springs, and the main channel receiving water from both previous mentioned water types.Accompanying observations of typical physico-chemical hydrologic characteristics with eDNA revealed that in the main channel and in the tributaries the biological richness increases according to change in streamflow, dq/dt. Whereas, in contrast, the richness in springs increased in correlation with electrical conductivity. At the catchment scale, our results suggest that transport of additional, and probably terrestrial, DNA into water storage or flow compartments occurs with increasing streamflow. Such processes include overbank flow, stream network expansion, and hyporheic exchange. In general, our results highlight the importance of considering the at-site sampling habitat in combination with upstream connected habitats to understand how streams integrate eDNA over a catchment and to interpret spatially distributed eDNA samples, both for hydrologic and biodiversity assessments. At the intersection of two disciplines, our study provides complementary knowledge gains and identifies the next steps to be addressed for using eDNA to achieve complementary insights into Alpine water sources. Finally, we provide recommendations for future observation of eDNA in Alpine stream ecosystems

Isotopes and related data associated with water tracing with environmental DNA in a high-Alpine catchment

Isotopes and related data associated with water tracing with environmental DNA in a high-Alpine catchment Prepared by Natalie Ceperley, February 2020. All methods associated with this data are available in the manuscript: Elvira Mächler, Anham Salyani, Jean-Claude Walser, Annegret Larsen, Bettina Schaefli, Florian Altermatt, and Natalie Ceperley. 2019. Water tracing with environmental DNA in a high-Alpine catchment, Hydrology and Earth System Sciences. https://doi.org/10.5194/hess-2019-551. Related data sets are and will be published in the Vallon de Nant Community on Zenodo. Associated sequencing data are publicly available on European Nucleotide Archive (Mächler et al., 2020). All isotope data analyzed in the laboratory of Torsten W. Vennemann at the University of Lausanne. All Files: ▪ NaN - No measurement or sample ▪ Details regarding measurement are available in paper or supplement. Files: 1) climate_hydro_2017_daily.csv ⁃ 16 columns: ⁃ 1. day of year with January 1, 2017 = 1 ⁃ 2-5. Q: daily mean, min, max, and baseflow discharge as measured at outlet (location ER/MR), in liters / day ⁃ 6. P: mean mm of rain across catchment per day ⁃ 7. SR: total solar radiation per day in W/hr/m2 as median of 4 meteorological stations ⁃ 8-10. SCA: mean, min, and max snow covered area on days with satellite imagery available for whole catchment area, in % ⁃ 11-13. water temperature, mean, min, and max, at outlet (location ER/MR), in degrees C ⁃ 14-16. air temperature, mean, min, and max at 4 meteorological stations, in degrees C 2) delta-18-O_permil.csv ⁃ stable isotopes of water (delta 18-O) in per mil ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 3) delta-2-H_permil.csv ⁃ stable isotopes of water (delta 2-H) in per mil ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 4) dqdt_outlet_prev48hrs.csv - dq/dt determined at the outlet for the previous 48 hours at sampling moment (TimeOfSamples_HR.csv) for each sampling site ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 5) ednasamplecount.csv - this is the tally of samples (1 sample includes 4 replicates) ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 6) electricalconductivity_instrument.csv ⁃ Code: 108 - post-analyzed using a glass bodied 6 mm probe in the laboratory (Jenway 4510, Staffordshire, UK). 102 - hand measurement with WTW (multi-3510 with a IDS-tetracon-925, Xylem Analytics, Germany) ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 7) electricalconductivity_uScm.csv - this is the electrical conductivity in micro siemens per cm, according to the instruments coded in electricalconductivity_instrument.csv ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 8) LC-excess.csv - this is the line control execss from the meteoric water line as determined by the samples in the file: precipitationistopemetadata.csv ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 9) locations.csv ⁃ Location codes used in other files. - Coordinates in CH1903 / LV03 and WGS 84 (lat/lon). Elevation in m. asl. 10) precipitationisotopemetadata.csv - This is the sampling information for the isotope data that was used to calculate the meteoric water line. - The full data set will become available in a subsequent publication on Zenodo linked to the same community. - 4 columns: - 1. code: rain (1) or snow (2) - 2. collection date and time - 3. elevation in m. asl. - 4. in the case of rain, this is the depth of collection in mm (area normalized volume), in the case of snow, this is the mean depth below the surface that the sample was taken from in cm. ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 11) sampledates.csv - These are the sample dates in day, month, year and day of year corresponding to the rows in other files 12) stationlocations.csv - These are the locations of four meteorological stations and discharge measurement station. - Coordinates in CH1903 / LV03 and WGS 84 (lat/lon). Elevation in m. asl. 13) TimeOfSamples_HR.csv - This is the time of the sample in hours and decimals correspond to minutes past hour ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) 14) watertemperature_degC.csv ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv) - measure in degrees C - instrument in watertemperature_instrument.csv 15) watertemperature_instrument.csv ⁃ Code: 1 = hand measurement with WTW (multi-3510 with a IDS-tetracon-925, Xylem Analytics, Germany) 2 = HOBO Pendant Temperature/Light Data Logger 64K - UA-002-64", Onset (Bourne, MA, USA) 3 = Continually logging WTW (IDS-tetracon-325, Xylem Analytics, Germany) 4 = Continually logging (10min) HOBO U24-001 Conductivity, Onset (Bourne, MA, USA) ⁃ columns correspond to sampling locations (locations.csv), rows correspond to sampling days (sampledates.csv)Funding is from the Swiss National Science Foundation Grants No PP00P3_179089, 31003A_173074 (to FA), PP00P2_157611 (to BS), the Velux Foundation, and the Chuard Schmid Foundation (to BS)

Need for harmonized long-term multi-lake monitoring of African Great Lakes

To ensure the long-term sustainable use of African Great Lakes (AGL), and to better understand the functioning of these ecosystems, authorities, managers and scientists need regularly collected scientific data and information of key environmental indicators over multi-years to make informed decisions. Monitoring is regularly conducted at some sites across AGL; while at others sites, it is rare or conducted irregularly in response to sporadic funding or short-term projects/studies. Managers and scientists working on the AGL thus often lack critical long-term data to evaluate and gauge ongoing changes. Hence, we propose a multi-lake approach to harmonize data collection modalities for better understanding of regional and global environmental impacts on AGL. Climate variability has had strong impacts on all AGL in the recent past. Although these lakes have specific characteristics, their limnological cycles show many similarities. Because different anthropogenic pressures take place at the different AGL, harmonized multi-lake monitoring will provide comparable data to address the main drivers of concern (climate versus regional anthropogenic impact). To realize harmonized long-term multi-lake monitoring, the approach will need: (1) support of a wide community of researchers and managers; (2) political goodwill towards a common goal for such monitoring; and (3) sufficient capacity (e.g., institutional, financial, human and logistic resources) for its implementation. This paper presents an assessment of the state of monitoring the AGL and possible approaches to realize a long-term, multi-lake harmonized monitoring strategy. Key parameters are proposed. The support of national and regional authorities is necessary as each AGL crosses international boundaries

Need for harmonized long-term multi-lake monitoring of African Great Lakes

To ensure the long-term sustainable use of African Great Lakes (AGL), and to better understand the functioning of these ecosystems, authorities, managers and scientists need regularly collected scientific data and information of key environmental indicators over multi-years to make informed decisions. Monitoring is regularly conducted at some sites across AGL; while at others sites, it is rare or conducted irregularly in response to sporadic funding or short-term projects/studies. Managers and scientists working on the AGL thus often lack critical long-term data to evaluate and gauge ongoing changes. Hence, we propose a multi-lake approach to harmonize data collection modalities for better understanding of regional and global environmental impacts on AGL. Climate variability has had strong impacts on all AGL in the recent past. Although these lakes have specific characteristics, their limnological cycles show many similarities. Because different anthropogenic pressures take place at the different AGL, harmonized multi-lake monitoring will provide comparable data to address the main drivers of concern (climate versus regional anthropogenic impact). To realize harmonized long-term multi-lake monitoring, the approach will need: (1) support of a wide community of researchers and managers; (2) political goodwill towards a common goal for such monitoring; and (3) sufficient capacity (e.g., institutional, financial, human and logistic resources) for its implementation. This paper presents an assessment of the state of monitoring the AGL and possible approaches to realize a long-term, multi-lake harmonized monitoring strategy. Key parameters are proposed. The support of national and regional authorities is necessary as each AGL crosses international boundaries