Autogenous Eutrophication, Anthropogenic Eutrophication, and Climate Change: Insights from the Antrift Reservoir (Hesse, Germany)

Abstract

Climate change is projected to aggravate water quality impairment and to endanger drinking water supply. The effects of global warming on water quality must be understood better to develop targeted mitigation strategies. We conducted water and sediment analyses in the eutrophicated Antrift catchment (Hesse, Germany) in the uncommonly warm years 2018/2019 to take an empirical look into the future under climate change conditions. In our study, algae blooms persisted long into autumn 2018 (November), and started early in spring 2019 (April). We found excessive phosphorus (P) concentrations throughout the year. At high flow in winter, P desorption from sediments fostered high P concentrations in the surface waters. We lead this back to the natural catchment-specific geochemical constraints of sediment P reactions (dilution- and pH-driven). Under natural conditions, the temporal dynamics of these constraints most likely led to high P concentrations, but probably did not cause algae blooms. Since the construction of a dammed reservoir, frequent algae blooms with sporadic fish kills have been occurring. Thus, management should focus less on reducing catchment P concentrations, but on counteracting summerly dissolved oxygen (DO) depletion in the reservoir. Particular attention should be paid to the monitoring and control of sediment P concentrations, especially under climate change.

Challenges and Successes in Identifying the Transfer and Transformation of Phosphorus from Soils to Open Waters and Sediments

“…In this special issue, we invited research and review articles that address the topic of soil P processes involving transfer and transformation across the landscape, either presenting novel research methods or synergy among non-traditional research fields; a review of existing successes and failures with underlying causes; or data-driven recommendations on the various approaches necessary to mitigate P loss and achieve the tangible goal of improving water quality. This volume contains eight original research articles [6][7][8][9][10][11][12][13] and two review articles [14,15].…”

“…General contribution papers covered the various aspects of basic-applied research on mineral-P interaction and how these reactions impact P mobilization, bioavailability, transfer [7], and speciation of P in different soil matrices using advanced analytical methods. Some of these methods included the application of XANES [13] and field-based research related to stream bank legacy nutrients [8]; natural and anthropogenic eutrophication, and its relationship to climate change [12]; and the evaluation of the impact of P due to (i) grazing systems [11], (ii) weathering and vegetation [6], and soil and manure management practices [10]. Together, these contributions improved our current understanding of the reactions and processes that impact P concentration, speciation, cycling, loss, and transfer from agroecosystems.…”