Tiny Creature, Big Impact: Warming Alters Lake Food Webs

Warming water temperatures are influencing the feeding habits of microscopic freshwater organisms, leading to potential shifts in entire ecosystems. Research from the HUN-REN Center for Ecological Research focused on Limnomysis benedeni, a tiny, invasive crustacean native to the Ponto-Caspian region.

This omnivorous mysid typically consumes both algae and small zooplankton. However, controlled experiments showed that as water temperatures increased, *L. benedeni* consumed relatively less animal prey and more algae. This dietary shift suggests a change in its ecological role from a zooplankton predator to a competitor for algal resources.

Scientists emphasize that such subtle changes, easily overlooked, can have significant consequences for aquatic food webs. Altered grazing and predation pressures on plankton can reshape nutrient flow and community structure. This highlights how climate change impacts can manifest through small, incremental shifts in species' behavior rather than solely through visible events like heat waves or mass die-offs.

The implications are particularly relevant given the abundance of this invasive species in many European waters. Even moderate dietary shifts in abundant invasive organisms can become ecologically significant, potentially impacting native grazers that also rely on phytoplankton. Further research is ongoing to understand these effects in more complex environments.