Biogeochemistry of natural ponds in agricultural landscape: Lessons learned from modeling a kettle hole in Northeast Germany

Gabriela Onandia; Gunnar Lischeid; Thomas Kalettka; Andreas Kleeberg; Mohamed Omari; Katrin Premke; George B Arhonditsis

doi:10.1016/j.scitotenv.2018.04.014

Biogeochemistry of natural ponds in agricultural landscape: Lessons learned from modeling a kettle hole in Northeast Germany

Sci Total Environ. 2018 Sep 1:634:1615-1630. doi: 10.1016/j.scitotenv.2018.04.014. Epub 2018 Apr 24.

Authors

Gabriela Onandia¹, Gunnar Lischeid², Thomas Kalettka³, Andreas Kleeberg⁴, Mohamed Omari⁵, Katrin Premke⁶, George B Arhonditsis⁷

Affiliations

¹ Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany. Electronic address: gabriela.onandia@zalf.de.
² Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany.
³ Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany.
⁴ Department Geology, Soil, Waste, State Laboratory Berlin-Brandenburg, Kleinmachnow, Germany.
⁵ Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany; Computational Systems Biology Group, Zuse-Institut Berlin, Berlin, Germany.
⁶ Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.
⁷ Ecological Modeling Laboratory, Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario, Canada.

PMID: 29710657
DOI: 10.1016/j.scitotenv.2018.04.014

Abstract

Kettle holes, small shallow ponds of glacial origin, represent hotspots for biodiversity and biogeochemical cycling. They abound in the young moraine landscape of Northeast Germany, potentially modulating element fluxes in a region where intensive agriculture prevails. The Rittgarten kettle hole, with semi-permanent hydroperiod and a surrounding reed belt, can be considered as a representative case study for such systems. Aiming to provide insights into the biogeochemical processes driving nutrient and primary producer dynamics in the Rittgarten kettle hole, we developed a mechanistic model that simulates the carbon, nitrogen, phosphorus and oxygen, phytoplankton, and free-floating macrophyte biomass dynamics. After model calibration and sensitivity analysis, our modeling exercise quantified the simulated nutrient fluxes associated with all the major biogeochemical processes considered by the model. Seasonality of nutrient concentrations, magnitude of primary productivity rates, and biogeochemical process characterization in the pond were reasonably reproduced by the model from July 2013 to July 2014. Our results suggest that the establishment of a phytoplankton community well-adapted to low light availability, together with the differential use of N and P from free-floating macrophytes and phytoplankton can explain their coexistence in kettle holes. Sediment nutrient release along with decomposition of decaying submerged macrophyte are essential drivers of internal nutrient cycling in kettle holes. Our results also suggest that the Rittgarten kettle hole act as a net source of CO₂ to the atmosphere on an annual scale, which offers a testable hypothesis for kettle holes with structural and functional similarities. We conclude by discussing the need to shed light on the effects of water level fluctuations on nutrient dynamics and biological succession patterns, as well as the relative importance of external sources and internal nutrient recycling mechanisms.

Keywords: Carbon flux; Internal nutrient recycling; Kettle holes; Macrophytes; Phytoplankton; Temporary ponds; Water quality.