Revolutionary eDNA Technology Could Transform Marine Monitoring in the Southern Ocean

In an exciting development for marine conservation, cutting-edge DNA technology is enhancing the ability to monitor marine life in the Southern Ocean and identify non-native species encroaching upon the pristine waters near Antarctica.

Groundbreaking Expedition

In 2019, a groundbreaking expedition aboard Australia’s former icebreaker Aurora Australis saw scientists embark on a remarkable 3,000 nautical mile journey from Hobart to the Davis research station. This ambitious venture involved collecting 138 seawater samples, from which researchers analyzed 'environmental DNA' (eDNA) to uncover which zooplankton species were present at the time of collection.

Role of Environmental DNA

Dr. Leonie Suter, a molecular geneticist with the Australian Antarctic Division, explained that the team compared the eDNA findings with those gathered using a Continuous Plankton Recorder (CPR), a device that captures zooplankton while being towed behind the vessel. "The CPR is essential for monitoring zooplankton diversity since 1991, yet its design leaves many delicate organisms damaged and unidentifiable," explained Dr. Suter.

With eDNA, however, the possibilities expand dramatically. "This method allows us to identify a wide range of organisms from mere traces in the environment, including faeces, eggs, and larvae," she added. The results were staggering; the research team found that eDNA detected 68 zooplankton species, significantly outpacing the 32 species discovered via the CPR, with only 12 shared by both methodologies.

Ecological Implications

The implications of these findings are profound. Dr. Suter emphasized how integrating eDNA with CPR data provides a "holistic view" of zooplankton diversity, crucial for recognizing ecological patterns that might otherwise remain unseen. For instance, gelatinous organisms may be more resilient to rising ocean temperatures, but relying solely on crustaceans could overlook these important shifts.

Marine Biosecurity Concerns

Notably, the eDNA method also revealed the presence of 16 non-native or potentially invasive species during the voyage, primarily near Tasmania, signifying areas of concern for marine biosecurity. Intriguingly, some species increased in detection as the team ventured into sea ice, possibly due to organisms clinging to the ship's hull being dislodged by the icy conditions.

Proactive Measures Needed

Kirsten Leggett, the Environmental Manager at the Australian Antarctic Division, echoed the importance of proactive measures to mitigate these risks. The new Australian icebreaker, RSV Nuyina, is outfitted with a comprehensive biofouling management plan to minimize the chances of inadvertently transporting non-native species into sensitive Antarctic ecosystems.

Future Research Directions

The dual approach of eDNA and CPR methodologies not only facilitates monitoring long-term ecological changes but opens new avenues for assessing marine biosecurity threats. As Dr. Suter noted, further research should focus on fine-tuning eDNA detection methods to swiftly identify non-native species, thereby safeguarding the vulnerable Antarctic environments.

Conclusion

With the publication of these findings in the prestigious journal *Science of the Total Environment*, there's a growing call within the scientific community to embrace eDNA technologies. This novel approach can enhance our understanding of marine ecosystems amid the harsh realities of environmental change and globalization.

Stay tuned as we unveil more groundbreaking research that could reshape our understanding of marine life and conservation in the Southern Ocean!