This story is part of an ongoing series high­lighting Northeastern’s research efforts at Mis­sion 31. Full cov­erage.

On a good day, corals make happy homes for pho­to­syn­thetic algae. It’s a coop­er­a­tive setup, with the algae turning dis­solved carbon dioxide into food for the coral and the coral pro­viding a nice roof for the algae.

But due to warming tem­per­a­tures and ocean acid­i­fi­ca­tion, good days are becoming fewer and far­ther between. More and more, algae are evac­u­ating their coral homes, leaving the corals hungry and sus­cep­tible to dis­ease. The phe­nom­enon is called coral bleaching because the algae also do their part to paint the marine inver­te­brates’ bodies the beau­tiful colors we’re familiar with—when there’s no one home, the corals turn white.

One way that corals are thought to weather this cli­mate change storm is by increasing their diet of zoo­plankton, the micro­scopic ani­mals dis­persed throughout the water column. “How­ever, too little is known about zoo­plankton dynamics specif­i­cally on coral reefs to know if this is a sus­tain­able solu­tion for coral recovery from bleaching,” said Amanda Dwyer, a grad­uate stu­dent in pro­fessor Mark Patterson’s lab at Northeastern’s Marine Sci­ence Center in Nahant, Massachusetts.

To get a better sense of zooplankton’s behav­iors and habits, Dwyer will be spear­heading one of four Northeastern-​​led sci­en­tific projects during Mis­sion 31, a month­long under­water research expe­di­tion cur­rently underway and led by Fabien Cousteau, grandson of the leg­endary ocean explorer Jacques Cousteau.

This is a very cool oppor­tu­nity to have one whole lunar cycle of data looking at the zoo­plankton,” Dwyer said. “The tides are based on the moon and so the lunar cycle really has a lot to do with ocean move­ment and ocean patterns.”

With a whole month of data, Dwyer and her col­leagues will pro­vide a foun­da­tion on which others will be able to examine impor­tant ques­tions about zoo­plankton dynamics, including how they move both within and between reefs.

For this par­tic­ular project, she and the four Mis­sion 31 aquanauts—who will be based full-​​time at the under­water research sta­tion Aquarius for the dura­tion of the expedition—will be col­lecting two types of data. First, they’ll be looking at migra­tion of zoo­plankton during the night from the bottom of the ocean floor to the sea sur­face. Second, they will trawl the water during the day at four points along the water column: at about one-​​half meter down, one meter down, and two meters down, as well as at the surface.

Amanda Dwyer, left, and fellow Mis­sion 31 team member Francis Choi training for the mis­sion at Northeastern’s Marine Sci­ence Center in Nahant, Mass. Photo by Mariah Tauger.

They’ll then take these sam­ples back to the lab where they’ll be able to figure out where in the water dif­ferent species reside at dif­ferent points during the day.

Nor­mally zoo­plankton migrate up to the sur­face of the water at night when there’s no light because that helps them avoid pre­da­tion from fish and it’s where their main food source, phy­to­plankton, is most abun­dant,” Dwyer said. “And then they go back down to the bottom during the day, which is a safer envi­ron­ment for them.”

While zoo­plankton dynamics may vary across dif­ferent reefs due to site-​​specific con­di­tions, this 31-​​day snap­shot will pro­vide a gen­eral base­line to begin com­paring zoo­plankton avail­ability with other stressed and unstressed reefs, Dwyer said. This would allow researchers to make pre­dic­tions about a reef’s poten­tial for success.