World’s Lakes Losing Oxygen Rapidly as the Planet Warms

Oxygen levels in the world’s temperate freshwater lakes are declining rapidly —faster than in the oceans— a trend that is driven largely by climate change, which threatens freshwater biodiversity and drinking water quality. Hydrochemist Josef Hejzlar from the Biology Centre CAS was involved in the research analyzing the dataset from the Czech reservoirs and lakes, which showed that in Central Europe, represented by the Czech Republic, changes are even more pronounced than in other parts of the world.

Research published in Nature found that oxygen levels in surveyed lakes across the temperate zone have declined 6 per cent at the surface and 19 per cent in deep waters since 1980. Meanwhile, in a large subset of mostly nutrient-polluted lakes, surface oxygen levels increased as water temperatures crossed a threshold favouring cyanobacteria, which can create toxins when they flourish in the form of harmful algal blooms. “All complex life depends on oxygen. It’s the support system for aquatic food webs. And when you start losing oxygen, you have the potential to lose species,” said Kevin Rose, author and professor at Rensselaer Polytechnic Institute. Lakes are losing oxygen 3-9 times faster than the oceans, a decline that will have impacts throughout the ecosystem.

Publication: Kevin Rose, et al., World’s lakes losing oxygen rapidly as planet warms, Biology Centre CAS (2023). DOI: 10.1038/s41586-021-03550-y

Original Story Source: Czech Academy of Sciences