Testing the effect of warming oceans
The world's oceans are important for both the global ecological balance and a number of ecosystem services like food production and transport. While scientists have tested the effects of terrestrial warming using greenhouses, no research has been done to look at the effects of ocean warming. The EU-funded CC AND MARINE LIFE (The influence of multiple global change stressors on marine communities: A novel field approach) project aimed to test how marine ecosystems respond to changes in surface and water temperature. To achieve this, researchers developed an underwater hotplate system – a collection of panels that can be heated to more than 10 °C above ambient temperature. The hotplate system could also record the nearby water temperature very accurately. CC AND MARINE LIFE first used the hotplate system to maintain a higher water temperature and study how the marine ecosystems colonised the panels. This experiment yielded very different ecosystems to the surrounding colder water, with bacteria and metazoans in much greater quantities. Overall, short-term temperature changes encouraged the growth of non-native species and common biofouling organisms. The project also left the hotplate system in the ocean to be colonised by marine organisms before being heated up. In this experiment, the temperature change did not have an effect on the already-established ecosystem. Lastly, CC AND MARINE LIFE studied the effects of increased temperature in ocean waters off western Australia during a 2011 heat wave. High temperatures killed off a common species of seaweed on the ocean surface, leading to widespread death and migration of marine invertebrates. This project has, for the first time, looked at how temperature changes might affect marine ecosystems. This will improve our ability to predict and manage the effects of rising ocean temperatures.
Keywords
Ocean warming, marine ecosystems, climate change, marine communities, hotplate system
