The study of nekton is an important part of marine biology.

My biological clock is disrupted, and I've been having sleepless nights.

Invasive species can have a major impact on the natural environment.

The government declared a state of emergency to prevent the spread of the new coronavirus.

The Irish Sea separates the UK and Ireland.

The Arctic Ocean is a cold and beautiful sea.

The South Polar Ocean is the coldest sea on Earth.

I have visited the Ionian Sea.

The Bohai Sea is one of the important sea areas of China.

I would like to visit the Dead Sea someday.