Data set of dissolved major and trace elements from the lacustrine systems of Clearwater Mesa, Antarctica

This article presents analytical observations on physicochemical parameters and major and trace element concentrations of water, ice, and sediment samples from the lake systems of Clearwater Mesa (CWM), northeast Antarctic Peninsula. Geo-chemical analyses include inductively coupled plasma mass spectrometry (ICP-MS) for cations and trace elements and ion chromatography for anions. Some figures are included (i.e. Piper and Gibbs diagrams) which indicate water classification type and rock-water interactions in CWM, respectively. It also contains PHREEQC software output, listing the chemical speciation for dissolved elements, Saturation Indexes (SI), and modelling outputs. Each lake SI are also illustrated in a figure. Finally, total organic and inorganic carbon (TOC and TIC, respectively) were determined for bottom lake sediments and marginal salt samples. This information will be useful for future research assessing the impacts of anthropogenic pollution and the effects of climate change, providing insights into naturally occurring geochemical processes in a pristine environment, and evaluating geochemical behaviour of dissolved elements in high-latitude hydrological systems. These data correspond to the research article "Dissolved major and trace geochemical dynamics in Antarctic Lacustrine Systems" [1]. (C) 2020 The Authors. Published by Elsevier Inc.

Dissolved major and trace geochemical dynamics in Antarctic lacustrine systems

Tyler Joe Kohler

Clearwater Mesa Uames Ross Island, northeast Antarctic Peninsula) provides a unique opportunity to study solute dynamics and geochemical weathering in the pristine lacustrine systems of a high latitude environment. In order to determine major controls on the solute composition of these habitats, a geochemical survey was conducted on 35 lakes. Differences between lakes were observed based on measured physico-chemical parameters, revealing neutral to alkaline waters with total dissolved solids (TDS) < 2500 mg L-1. Katerina and Trinidad-Tatana systems showed an increase in their respective TDS, total organic carbon values, and finner sediments from external to internal lakes, indicating an accumulation of solutes due to weathering. Norma and Florencia systems exhibited the most diluted and circumneutral waters, likely from the influence of glacier and snow melt. Finally, isolated lakes presented large variability in TDS values, indicating weathering and meltwater contributions at different proportions. Trace metal abundances revealed a volcanic mineral weathering source, except for Pb and Zn, which could potentially indicate atmospheric inputs. Geochemical modelling was also conducted on a subset of connected lakes to gain greater insight into processes determining solute composition, resulting in the weathering of salts, carbonates and silicates with the corresponding generation of clays. We found CO2 consumption accounted for 20-30% of the total species involved in weathering reactions. These observations allow insights into naturally occurring geochemical processes in a pristine environment, while also providing baseline data for future research assessing the impacts of anthropogenic pollution and the effects of climate change. (C) 2019 Elsevier Ltd. All rights reserved.

2020

Global and local anthropogenic effects on hydrodynamics of lakes

Carl Love Mikael Råman Vinnå

In many countries water quality is a major concern for drinking water management authorities. Freshwater is a limited resource and the demand for good-quality water from natural aquatic systems is therefore high. Additional stress arises from anthropogenic emissions of nutrients, chemicals, pathogens, heat and hydrological alterations as well as from the ongoing global climate change. In this thesis the relevant recent past, present and future factors affecting water quality in the perialpine Lake Biel, used as a source for drinking water, was investigated. Through measurements in the field combined with hydrodynamic logical modelling in one and three dimensions, optimal locations for forthcoming lake water intakes was identified. Water quality properties considered were temperature, oxygen, suspended sediment concentration (SSC) and the risk of subaqueous mass movements. The results identified the forthcoming changes expected in Lake Biel due to the upcoming decommission of the Mühleberg Nuclear Power Plant (MNPP) in 2019. This plant currently release ~700 MW of heat into the upstream Aare River in the form of cooling water. The removal of this anthropogenic thermal source will decrease future lake temperature by ~0.3 °C (volume average). Due to seasonal river discharge patterns, the main impact of the plant closure will occur during winter. Minor effects are expected in summer in the form of moderately weaker lake stratification. Furthermore, the current fate of thermal pollution emitted from MNPP was linked to the hydraulic residence time of Lake Biel. While short-term anthropogenic thermal impacts in Lake Biel can be large, the system is additionally experiencing continuous warming up to ~0.1 °C per decade (volume average) by the ongoing climate change. The climate effect on Lake Biel and its primary tributary, the Aare River, was investigated as well as compared to the much larger Lake Geneva and Rhône River. Climate change causes seasonal river discharge shifts resulting in enhanced river warming in summer and diminished warming in winter, while at the same time SSC increases in winter and decreases in summer. Differences in temperature as well as warming rates between rivers and lakes in turn resulted in a discharge and hydraulic residence time-dependent decrease in climate warming of lakes. Furthermore, deep-water renewal in both lakes is predicted to increase in summer and decreases in winter, possibly influencing the replenishment of deep water oxygen. Additionally, sedimentation patterns in Lake Biel were examined and linked to the historical diversion of the Aare River into the lake. The majority of sediment supplied to Lake Biel (~80 %) came from large SSC events in the Aare. These events resulted in a selective particle settling pattern, which concentrated sedimentation on the shallow shelf area North-East of the Aare delta. Both the large SSC events as well as this selective sedimentation pattern were connected to weather fronts coming in from the Atlantic Ocean. The research performed here opens up for further promising interdisciplinary research between Meteorology, Climatology, Hydrology and Sedimentology. Inland water management would benefit through increased knowledge regarding the propagation of particles and/or anthropogenic heat, from river catchments into downstream lakes and sediments.

EPFL2018

Human domination of the global water cycle absent from depictions and perceptions

Camille Roland Marie Minaudo

Human water use, climate change and land conversion have created a water crisis for billions of individuals and many ecosystems worldwide. Global water stocks and fluxes are estimated empirically and with computer models, but this information is conveyed to policymakers and researchers through water cycle diagrams. Here we compiled a synthesis of the global water cycle, which we compared with 464 water cycle diagrams from around the world. Although human freshwater appropriation now equals half of global river discharge, only 15% of the water cycle diagrams depicted human interaction with water. Only 2% of the diagrams showed climate change or water pollution-two of the central causes of the global water crisis-which effectively conveys a false sense of water security. A single catchment was depicted in 95% of the diagrams, which precludes the representation of teleconnections such as ocean-land interactions and continental moisture recycling. These inaccuracies correspond with specific dimensions of water mismanagement, which suggest that flaws in water diagrams reflect and reinforce the misunderstanding of global hydrology by policymakers, researchers and the public. Correct depictions of the water cycle will not solve the global water crisis, but reconceiving this symbol is an important step towards equitable water governance, sustainable development and planetary thinking in the Anthropocene.

NATURE PUBLISHING GROUP2019

Global and local anthropogenic effects on hydrodynamics of lakes

Carl Love Mikael Råman Vinnå

EPFL2018