A mere whiff of penguin poo pushes krill to take frantic evasive action

Imagine looking at the world through the eyes of the cill stalk in the southern ocean. Suddenly, a penguin looks like a giant giant, which is streamlined like a torpedo, pursuing and consumes thousands of krills at a rapid speed.

Now, researchers have shown that these flightless birds are sufficient to produce the creel to show the behavior of avoiding the smell of water.

“Here we show for the first time that a small amount of Penguin Guano causes a sudden change in the feeding and swimming behavior of the Antarctic Krill,” Dr. Nicole Hrisi said, a postdotoral researcher in Biglo Laboratory for Ocean Sciences in Main, and a new study writer Published In Limitations in marine science,

As a meal for stacks of species and large -scale sequences of carbon, the Crill Antarctic has a keystone species. It is estimated that today there are about 700 trillion adults in the southern Ocean, but their population is moving south due to the loss of climate change, sea ice and ocean acidication.

There is something in water

Zoplankton such as cills are sensitive to chemical signals about food, peers, and pollution and customize their behavior accordingly, and Hels and colleagues wanted to know if Krill also does so in response to smell from predators. The authors focused on the Penguin’s most southern breeding reproductive species, Edelis, as 99.6% of their diet includes the Antarctic Krill. An adult adélie eats up to 1.6 kg per day, and the annual consumption of the Antarctic Krill by the world’s population is about 1.5 million tonnes.

In the late 2022, researchers trapped the research ships “Lawrence M Gold” and “Nathanial B Palmer” at the Bransfield Strait, Antarctica to the Antarctic Krill to take to the research aquarium of Palmer Station. The catch was kept alive in placing tanks on the diet of algal solution. Bird experts first smelled 78 grams of Edelie Guano (“Rotten Shellfish. Not pleasant to handle, Helsay said) Helse said) a colony on the island of Torrerson, away from the Antarctic Peninsula near Palmer station.

To test the krill’s response to Guano, scientists kept a five -minute test of six to eight cills per five minutes in a flue filled with seawater at a temperature of 1.5 ° C. The light was slow to mimic the intensity of a depth of 40 meters, the most productive layer within the southern ocean. The water flows through the flom with a velocity of 3 cm or 5.9 cm per second. This flow was fed with three types of seawater: either algae, adi po, or both. Overall, he tested each combination of flow velocity and water structure four times.

He recorded the behavior of four individual cills per test per test with two automatic cameras, and these videos processed the 3D position of each cill and its speed and the swimming direction during the entire test.

The results showed that Krill usually floats directly upwards, a behavior called reotauxis. But once in the presence of Pu, they dramatically replaced their behavior: they differ more to their swimming speed, while 1.2 to 1.5 times faster. He also made three times more turns, at an angle which was 1.4 times more on an average.

In a second set of experiments, researchers showed that Krill reduced its rate of algae by 64% for food when penguin poo was added to water, dropped from 12.7 micrograms of carbon per hour per hour (or 13% of their body mass) per hour per hour 4.6 micrograms per hour. These results indicate that the Krill in the presence of Guano less efficiently, due to the frequent changes of the direction.

The authors concluded that this “zigzaging” is a reaction of a avoidance or escape.

“Such behavior will greatly increase the possibilities of the Krill’s existence to avoid nearby penguins. And these obstacles will grow rapidly in a herd, if their neighbors can detect the same signal and communicate the danger to each other,” Helsy said.

Krill smells like soul

But which chemicals krill responded inside Poo? This remains clear.

“We hypothesize that the Antarctic Krill Penguin is surviving the smell of ground-up cill and fish in Guiano.

“We do not yet know how the ability to understand these chemical signs and their escape behavior towards them may be different when in open water, or diluted in a state of global warming or ocean acidication. Any change in the behavior of the Krill can have a major impact on the southern ocean of the future, as the Antarctic Crill is a one of the innovative mechanisms.”