Shifting marine animals: Depth vs. latitude

By Rachel Berman

A diver experiences a unique vertical habitat in the Pacific. Credit: Twilight Zone Expedition Team 2007, NOAA-OE

If you’ve looked at the information available on our website, you’ll find that we track species not only by their latitudinal movement, but also by the shifts in depth that the population experiences over time. To put this into perspective, if you were to start at New York City and drive to southern Maine, you have moved latitudinally (similar to the shift we’ve seen in American lobster). You might find the climate to be a little cooler further from the equator.
How about depth/elevation? Climb up a mountain and you might find yourself more exposed to the rays from the sun, surrounded by thinner, colder air, and it might be a little breezier the higher you go. In the ocean, the changes that occur with depth are related, but a bit different. There are about 5000 meters (16,400 feet) between the “sunlight zone” and the “abyss.”
The layers of the ocean have different properties, and they each host a different set of characteristic inhabitants. The photic (epipelagic) zone is the top layer of the ocean where light from the sun supports the growth of phytoplankton and algae. These phytoplankton then support a wide range of fish and invertebrates, especially on the relatively shallow continental shelves that surround each continent. Overall, species tracked on the OceanAdapt size have moved an average of almost 10 meters deeper over the last three decades. While not dramatically deeper, it suggests that many species are moving offshore in search of cooler waters.

Read about shifting marine species: