Tangaroa voyage: Northern Victoria Land's coastal marine life
A key focus for the Antarctic Science Platform on the 2023 Tangaroa voyage was gathering new information on shallow ecosystems along the Northern Victoria Land coastline, to better understand how marine life in the area may respond to future warming and sea ice loss.
To undertake the work, the ship was required to work very close to shore - incredible views, but logistically challenging, with ice bergs and sea ice having to be negotiated. This year, the team were able to access enough nearshore water to complete planned research into coastal benthic biota.
Led by Prof. Miles Lamare (University of Otago and Co-PI of Project 3), ASP coastal work was undertaken at eight key sites, from Cape Wheatstone in the south to Robertson’s Bay at the northern end of the Ross Sea coastline. Researchers gathered information on species distributions and biodiversity, how coastal food-webs function, and how benthic communities are structured by the physical environment.
Left: The seafloor off Cape Hallett Peninsula, with diverse marine life at 100 metres. The photo (about 1 m2 in area) was taken using NIWA’s towed imaging system (DTIS) and shows the abundant sponges, soft coral, ascidians and crinoids that cover the sea floor. Right: A DTIS image of the deep seafloor (433 m) off the Northern Victoria Land coast. The large bolder (about 1 m across) is home to brittlestars, soft corals and colonies of pink Stylasterid hydrocorals. Credits: Miles Lamare, Sadie Mills (NIWA), Steve George (NIWA)
To undertake the work, the researchers first made detailed maps of the seafloor that allowed them to then tow camera and video systems, gathering high resolution images of the sea floor and marine life along the coast. The detailed mapping of biodiversity that came from this imagery was followed by targeted sampling of the seafloor marine life, so that the scientist can build a picture of how the ecosystems function along the coast in terms of energy flow, productivity and connection with other parts of the Ross Sea.
RV Tangaroa at Cape Wheatstone. Photo: Joshu Mountjoy/NIWA
Over the course of a week dedicated to this work, researchers gathered over 4,000 camera images of benthic marine life, and filmed 41,000m2 of sea floor previously unseen. At the same time, over 20,000 samples were collected for analysis back in New Zealand over the coming year.
The Tangaroa voyage supports ASP research into the biological and physical aspects of Ross Sea ecology that provides fundamental information essential to understanding threats from the changing environment. Field work of this kind is critical to development and validation of the projection models that the ASP is developing to better understand climate-related threats to the Ross Sea Marine Protected Area and further afield.