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# Responses of primary producers, anoxia, and chemical feedback to Late Glacial climate change: Insights from a paired lake approach

## Details

**Authors** Noé R.M.M. Schmidhauser, Stan J. Schouten, Petra Zahajská, Andrea Lami, Jacqueline F.N. van Leeuwen, Rik Tjallingii, Hendrik Vogel, Martin Grosjean

**Year** 2026

**Publisher** Journal of Quaternary Science

**Kind of work** article

**Discipline** Geology

**Secondary disciplines** Climatology

[Read it at the publisher](https://doi.org/10.1002/jqs.70115) 
10.1002/jqs.70115

## In authors' words

### Abstract

Worldwide, lacustrine ecosystems are threatened by eutrophication and deoxygenation. Both processes are driven by the combined effects of human activities and climate change. Understanding the pre‐anthropogenic nexus between warming, eutrophication, deoxygenation, and related feedback is essential to determine how lakes respond to rapid climate change. We investigate the responses of primary producers, stratification, and nutrient cycling in a small Central European lake (Übeschisee, Swiss Plateau) to rapid climate change during Late Glacial times (17–11 ka). After 16.2 ka (Heinrich Stadial; HS1) and during the Bølling/Allerød interstadial, Übeschisee experienced natural eutrophication following summer warming and vegetation development in the catchment. Anoxia events with blooms of sulfur bacteria systematically established during colder periods of HS1 (16.5 ka), the Older Dryas (14 ka), the Gerzensee Oscillation (13.2 ka), and the Younger Dryas (12.7–11.7 ka). Anoxia events also caused reductive dissolution of Mn; labile P was always efficiently recycled. Algal communities responded to anoxia events, but the excursions of community composition were reversible. Ti follows NGRIP Dust, suggesting that Übeschisee provides a continuous record of dust deposition with high rates during colder periods. The paired lake approach with adjacent Amsoldingersee shows that the results are robust and regionally reproducible, and that common drivers influenced both lakes simultaneously.

### What they set out to do (purpose)

To determine how a small pre-anthropogenic lake system responds to rapid natural climate change, isolating climate-driven feedback among warming, eutrophication, anoxia and nutrient cycling from confounding human impacts.

### Who or what was studied (sample)

Sediment cores from two adjacent Swiss lakes (Übeschisee and Amsoldingersee, Swiss Plateau) spanning the Late Glacial period (~17,000–11,000 years ago).

### How they did it (methods)

Multi-proxy paleolimnological analysis (pigments, geochemistry, Mn/P speciation, algal community microfossils, XRF scanning) compared against the NGRIP ice-core dust record, with a paired-lake replication design to test regional robustness.

### What they found (results)

Cold intervals (HS1, Older Dryas, Gerzensee Oscillation, Younger Dryas) repeatedly triggered anoxia with sulfur-bacteria blooms and reductive Mn dissolution, while warm intervals drove eutrophication from summer warming and catchment vegetation growth, with the same coupled pattern occurring simultaneously in both paired lakes.

## Commentary

### In short

The study demonstrates that a lake ecosystem's climate response is structured as a causal feedback network operating within a nested lake-catchment system, with anoxic and oxic states forming a recurring categorical distinction tied to discrete climate intervals.

**Patterns it shows** D, S, R

Shows the structure is there, Shows it makes a difference

**Added** 2026-09-17

**How to cite this** Noé R.M.M. Schmidhauser, Stan J. Schouten, Petra Zahajská, Andrea Lami, Jacqueline F.N. van Leeuwen, Rik Tjallingii, Hendrik Vogel, Martin Grosjean (2026). Responses of primary producers, anoxia, and chemical feedback to Late Glacial climate change: Insights from a paired lake approach. Journal of Quaternary Science.