Antarctic coastal freshening threatens marine life, study warns

Researchers from the University of Plymouth and the British Antarctic Survey have found that reduced salt levels in Antarctic coastal waters, driven by melting glaciers and increased rainfall, pose a serious risk to marine invertebrates. The study focused on the amphipod Paraceradocus miersi, whose body fluids normally match seawater chemistry. Continued freshening could disrupt local ecosystems and potentially alter global ocean dynamics.

The study's observations stem from an extreme freshening event witnessed at Rothera Research Station on the Antarctic Peninsula in 2017. During experiments simulating diluted seawater, Paraceradocus miersi showed partial ability to regulate calcium, a chemical essential to its bodily functions, yet failed to maintain overall ion balance. This caused salt loss, water uptake, and gill damage—effects that could prove lethal for shallow-dwelling populations.

The research builds on nearly four decades of work by lead author John Spicer examining climate impacts on marine organisms. Because amphipods are abundant and ecologically important in Antarctic waters, their decline could ripple through the food web. The authors emphasize that Antarctic ecosystems are integral to global environmental health, meaning regional freshening may have consequences extending far beyond the continent's shores.