Far from being frozen and sterile environments, glaciers are biogeochemical reactors and regulators. A new review, led by Jon Hawkings and co-authored by Marek, discusses the hydrology and biogeochemistry of glacierised environments and their impact on downstream ecosystems.

All the key topics in current glacial biogeochemistry are addressed:

• supraglacial meltwaters exporting labile organic carbon associated with active supraglacial microbial communities, as well as carbon and nutrients delivered via atmospheric deposition;
• meltwaters funnelled to the glacier bed and exiting at the glacier snout transporting large quantities of rock flour as well as supraglacial and subglacial-derived organic carbon and nutrients to downstream ecosystems;
• subglacial water flow paths influencing rock–water contact times and affecting weathering reactions;
• microbial processes and physical-chemical weathering sequestering or emitting greenhouse gases;
• meltwaters potentially fuelling biological processes in downstream ecosystems by priming glacier-fed streams, fjords, and oceans with rock flour and nutrients.

The rapid reduction in glacier area projected for the next century mandates that future research provides a critical assessment of the effects of deglaciation on watershed biogeochemistry, ecology and global biogeochemical cycles.

The review is dedicated to the memory of Maya Bhatia, who died unexpectedly during
the writing of this review. Maya made key contributions to our understanding of glacier biogeochemistry that are described in the article, without which the field would be in a far more premature position. Maya was an outstanding person, scientist, colleague and friend, and is sorely missed.

Hawkings JR, Bradley JA, Doting EL, Hassan N, Hendry KR, Holt AD, Hood E, Spencer RGM, Stibal M, Tranter M, Venturelli RA, Wadham JL, Bhatia MP (2026) Glacier biogeochemical cycling and downstream impacts. Nature Reviews Earth & Environment doi:10.1038/s43017-025-00751-1