Why marine mammals are climate sentinels

What actually is an climate or ecosystem sentinel ? It is something that indicates an ecosystem response to environmental changes and variability, that would have been unobserved otherwise.

Many marine predators and other marine mammals are often conspicuous and wide ranging, and also integrate information from the abyss to to surface layer, aswell as from the bottom to the top of the food web. Since most mammals are at the top of the food chain, they act as important regulators of the tropic levels below.  

Many marine mammals have long life spans, are long term coastal residents, feed at the high trophic level and have unique fat reserves that can serve as depots for anthropogenic toxins. Many of those species share coastal regions with humans and consume the say food, thus can give important insight for public health problems. Facing anthropogenic changed,many of those may be exposed to stressors such as chemical pollutants, algal biotoxins and pathogens.

Taking whales as an example, they play a significant role in capturing carbon from the atmosphere; each great whale sequesters an estimated 33 tons of CO2 on average. Warming ocean temperatures and loss of sea ice in the Arctic and Antactic can affect the feeding habits and food abundance of those whales. The plankton they feen on, will most likely move and decrease in abundance as currents and winds change. This will then change the migration pattern and distance, leaving less time to forage for food, thus also hurt the reproductive rates of endangred species.

Ecosystems really are a hamsterwheel of codependet factors, that are a lot more vulnerable than we can imagine. Rapid change in Anthropocene and its environment doesn’t give enough time for those species adapt and creates necessities to develop new tools to measure ecosystem dynamics.

by Paulina Kalita