Exploring the Deep Sea Like a Native – oceanbites

Angelakis, N., Grammer, G. L., Connell, S. D., Bailleul, F., Durante, L. M., Kirkwood, R., Holman, D., & Goldsworthy, S. D. (2024). Using sea lion-borne video to map various benthic habitats in southern Australia. Frontiers in Marine Science, 11, 1425554. https://doi.org/10.3389/fmars.2024.1425554

The depths of our huge ocean are largely undiscovered. However, as technology continues to advance, new strategies of deep sea exploration are being developed. Previously, researchers have used remotely operated underwater automobiles (ROVs) and cameras dropped from ships to gather video footage of and map unreachable habitats. These strategies are cost- and time- consuming. Additionally, in Australia, these strategies offered little or no details about the underwater world. What if, as a substitute, we utilized animals who call these depths home to discover the ocean?

In this research, researchers posit a new method to benthic (sea ground) surveying and mapping: attaching cameras to Australian sea lions (scientific title Neophoca cinerea) to view the seafloor via their eyes. This novel methodology is faster, cheaper and more far-reaching than conventional exploration strategies.

Seal Bay Conservation Park. Image credit: Roger Smith through Flickr Creative Commons

Seeing the World Through Sea Lions’ Eyes

Australian sea lions are endangered predators that spend most of their time searching on the seafloor. They roam a number of habitats, together with sand plains and seagrass meadows. Because of their various vary, researchers on this research selected to survey the South Australian continental shelf by attaching video cameras to eight feminine sea lions.

The research happened over the course of 9 months off of two islands internet hosting the greatest sea lion colonies in Australia: Olive Island Conservation Park and Seal Bay Conservation Park. Sea lions have been sedated and anesthetized whereas the cameras, GPS, and acceleration and magnetic subject measurement units have been connected to neoprene (rubber) patches on their fur. Their vitals have been checked incessantly to make sure that they remained bodily healthy. Sea lions have been launched after which recaptured after 2-10 days. 

Researchers collected video footage during daytime, solely when the sea lions ventured decrease than 5 meters under the floor. The GPS tracked the areas at which the sea lions surfaced. Depth was measured each second and time spent and distance traveled in every habitat kind have been recorded. This knowledge was used to measure % cowl of every habitat. The animal-borne knowledge was mixed with environmental knowledge, comparable to sea floor temperature and bathymetry, to foretell how environmental components could affect habitat distribution in the research space. 

So What Does The Australian Seafloor Look Like?

Researchers collected a whole of 89 hours of footage and 560 km of habitat. The footage captured six distinct habitats: macroalgae reef, macroalgae meadow, naked sand, sponge/sand, invertebrate reef, and invertebrate boulder habitats. Percent cowl of every of these habitat varieties assorted between the two research websites.

Combining the knowledge captured by the sea lion footage with environmental knowledge, fashions have been in a position to predict benthic habitats 99.5% and 98.6% precisely for Olive Island and Seal Bay, respectively. Specifically, the fashions predicted that the majority of the southern Australian continental shelf is roofed by invertebrate reef, naked sand, and sponge/sand habitats. 

Notably, the findings of this research revealed more about benthic habitats in Australia than earlier research have, even those who have used animal-borne video for mapping. 

Australian sea lion. Image credit: Sheila Thomson through Flickr Creative Commons 

What Do We Know About Benthic Habitats Now?

The strategies on this research offered new insights into the options of benthic habitats the place Australian sea lions forage. For instance, when macroalgae reefs and meadows weren’t current, the seafloor was dominated by invertebrates.The distribution of these invertebrate communities might be predicted by the environmental variables utilized in the fashions for the research.

The digicam footage from this research additionally confirmed a selection of coral communities off the Australian coast. The researchers hypothesized that the spectacular dimension of these communities was doubtless due to the nutrient-rich water offered by seasonal upwelling and water circulation adjustments. The fashions created on this research supported this principle as they instructed that chlorophyll-a (an indicator of high charges of photosynthesis) was an important predictor of benthic habitat. Further, naked sand plains have been one other common habitat that appeared on the video footage. These areas may obtain fewer vitamins than benthic habitats, explaining why fewer animals have been discovered there. 

So What?

Mapping and surveying efforts reveal adjustments in the marine surroundings, particularly adverse adjustments which were brought on by human exercise. Discovering new strategies by which to view and discover the ocean can help scientists determine these points more shortly, main to raised restoration tasks and coverage adjustments. These strategies can be used to find new habitats and communities, particularly for species like the Australian sea lion, whose population has decreased by more than half in the previous 40 years. 

What subsequent? 

Future analysis ought to make the most of animal-borne video surveying along with present strategies to make sure that the advantages of all strategies are taken benefit of. Applying this research to different areas and different marine mammals may additionally present a more complete understanding of our ocean, particularly components which are unreachable by conventional strategies.

Cover photograph by Brian M. Hunt through Wikimedia Commons