Science & Technology (Commonwealth Union) – A recent study highlights the potential impact of ocean biology and marine pollution on Antarctica’s coastline.
The unique ecosystems of Antarctica could be at risk from the introduction of non-native marine species and pollution originating from landmasses in the Southern Hemisphere, according to new oceanographic modelling.
Appearing recently in Global Change Biology, the research conducted by scientists from UNSW Sydney, ANU, University of Otago, and the University of South Florida reveals that floating debris can reach Antarctic waters from more locations than previously believed.
Dr. Hannah Dawson, the lead author who conducted the study as part of her PhD at UNSW and now works at the University of Tasmania emphasized that due to the increasing presence of plastics and other man-made debris in the oceans, there are more chances for organisms to reach Antarctica.
Researchers of the study indicated that non-native species, including various small marine invertebrates, can make their way to Antarctica by hitching a ride on floating materials like kelp, driftwood, pumice, and plastic. While it was previously thought that these species only drifted from isolated islands in the Southern Ocean, the new findings suggest they can also reach the Antarctic coast from all southern continents.
Dr. Dawson indicated that it was already known that kelp could drift to Antarctica from nearby sub-Antarctic islands like Macquarie and Kerguelen, but their research indicates that floating materials might reach Antarctica from much farther away, including regions like South America, New Zealand, Australia, and South Africa.
Professor Crid Fraser from the University of Otago, who co-authored the study, warns that kelp could pose a serious threat to Antarctica’s marine ecosystem.
Professor Fraser stated that the Southern bull kelp and giant kelp are quite large, often exceeding 10 meters in length, and they provide a forest-like habitat for many small animals, which can be transported with them on these long journeys to Antarctica.
She also indicated that if they establish themselves in Antarctica, the marine ecosystems there could undergo significant changes.
With the application of surface current and wave data models from 1997 to 2015, the researchers traced the journey of floating debris from various sources in the Southern Hemisphere to Antarctica, offering new insights into the frequency and routes of marine dispersal.
ANU co-author Dr. Adele Morrison stated that they were able to assess how often these rafting connections occur by simulating dispersal pathways over 19 years of varying ocean conditions.
Dr. Morrison also pointed out that they discovered that floating objects reached the Antarctic coastline in each year they simulated and there seems to be a constant influx of anything that can float – whether it’s kelp or plastic bottles.
Dr. Dawson compares the computer modeling process to the children’s game ‘Poohsticks’ from Winnie the Pooh.
She painted a picture of dropping a stick into a stream and then running downstream to see where it ends up, indicating that it is essentially what they do with their modeling, using simulated ocean currents instead of a stream.
Dr. Dawson stated that they released millions of virtual particles, representing drift objects, from each source landmass and tracked their paths over 19 years of estimated surface ocean currents and waves. After running the simulations, they could see where they would likely end up.
She added that the shortest time it took for particles to reach the Antarctic coastline was from Macquarie Island, south of New Zealand, with some arriving in just under nine months. On average, the longest journey was for objects released from South America.
“Most of these rafting objects arrive at the tip of the Antarctic Peninsula, a region with relatively warm ocean temperatures and often ice-free conditions. These factors make it a likely area for non-native species to first establish,” explained UNSW Scientia Professor Matthew England, who is a co-author as well.
