Federal researchers are collecting plankton samples and floating plastic debris between Hawaii and the West Coast.

Scientists aboard the National Oceanic and Atmospheric Administration ship Okeanos Explorer are gathering the samples on their way back from an expedition to Southeast Asia.

They are due to return to Alameda, Calif., Monday.

Sampling operations chief scientist Michael Ford says there are some gaps in the plankton sampling records. He says scientists need samples to better describe the diversity and distribution of plankton.

Ford says this will help scientists detect changes and better understand how plankton responds to plastic debris that’s in the ocean.