Krill are tiny little crustaceans, living in the world’s oceans. They are small and, as people think, only good for whale food. A new research, which involved scientists from Australia, UK, Germany, and the US, revealed that krill are much more important for Earth’s climate than you could believe.
Krill are eaten not just by whales – penguins and many other birds and fishes enjoy them too. In this way they are very important, although the population of krill is vulnerable to human activities. People harvest krill to make livestock feed and human food. Krill oil and shrimp paste are probably the most well-known ways to consume krill. However, krill is also very important for the ocean’s carbon sink.
You know that trees and other green plants are consuming CO2 through photosynthesis. What you might not know is that oceans are also taking part in this process. Oceans are filled with phytoplankton, which are also able to photosynthesisz. Of course, krill do not participate in photosynthesis, but they do consume phytoplankton and excrete pallets that then sink to the seafloor. Scientists say that krill excrements constitute a majority of all the carbon that is sent to the bottom of the ocean.
This is how krill is participating in the global CO2 cycles and scientists would like people to pay attention to that. The issue is that even though fishing can access only about 0.5 % of all available krill, this can still have an impact on CO2 sink in the ocean. Especially since fishing can intensify in the near future. Also, the effects would not only be about CO2 sinking. Dr Emma Cavan, leader of the study, said: “a decline in krill would decrease the beneficial fertilization effect that their faecal matter has on phytoplankton biomass, at the same time also jeopardizing the important part krill play in circulating iron and other nutrients”.
Arctic krill grow up till 6 cm in length. They are small, but they are very significant. Since there is a global movement against fishing bigger fish, krill seems to be the source of food for the future, especially since it is already enjoyed in many parts of the world. However, before increasing the intensity of krill harvesting, people should consider what kind of an impact that could have on the bigger ecosystem and climate.
Scientists say that more research is needed to understand this issue better. And that is definitely coming. We also need to improve fishing methods to ensure that larval krill is safe from our fishing practices. At the end of the day, we need more accurate estimates of the significance of krill, its biomass and the impact of krill harvesting.
Source: University of Tasmania