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

Nine miles off the coast of Key Largo, Fla., and 63 feet beneath the waves lies the world’s only under­water research lab: Aquarius. “There’s no place like it on earth,” said Mark Pat­terson, pro­fessor of marine and envi­ron­mental sci­ence and civil and envi­ron­mental engi­neering at North­eastern Uni­ver­sity, who has vis­ited and lived within the “habitat” 10 times.

In the years it has been sub­merged, Aquarius has inti­mately assim­i­lated into the coral reef nearby. Sponges and corals dec­o­rate the exte­rior and a 700-​​pound grouper has taken up res­i­dence under­neath. Inside, it’s a ver­i­table under­water apart­ment com­plex com­plete with kitchen, sleeping quar­ters, and Wi-​​Fi.

It’s like a minia­ture city immersed in the envi­ron­ment,” said Brian Hel­muth, a pro­fessor of marine and envi­ron­mental sci­ence and public policy at Northeastern’s Marine Sci­ence Center, which is located on a penin­sula at his­toric East Point in Nahant, Mass.

Focused on urban coastal sus­tain­ability, the MSC researchers have a strong interest in under­standing deeply inte­grated human-​​ocean sys­tems such as Aquarius. Oper­ated by Florida Inter­na­tional Uni­ver­sity, the habitat will become home to a team of aquanauts—including Helmuth—beginning on June 1 for a 31-​​day expe­di­tion, aptly named Mis­sion 31. Fabien Cousteau, grandson of Jacques-​​Yves Cousteau, the famed ocean explorer and cre­ator of the first ocean floor habi­tats for humans, will spear­head the mis­sion in honor of the 50th anniver­sary of his grandfather’s Con­shelf Two mission.

The over­ar­ching theme for Mis­sion 31 is the human-​​ocean con­nec­tion within the lens of explo­ration and dis­covery,” Cousteau said.

North­eastern will take the lead as sci­en­tific partner during the second half of the mis­sion, when Hel­muth will begin his two-​​week-​​long sub­mer­sion. The expe­di­tion aligns with Northeastern’s focus on solving global chal­lenges in sus­tain­ability, one of the university’s core research themes.

The extended length of the dive allows the aqua­nauts to “sat­u­rate,” meaning the gases inside their bodies equi­li­brate with the sur­rounding high-​​pressure envi­ron­ment. This allows for more in-​​depth, long-​​term research inves­ti­ga­tions not nor­mally per­mitted during the stan­dard hour-​​long dives, which require a period of depres­sur­iza­tion or “off­gassing” in order to pre­vent serious illness.

As part of Mis­sion 31, North­eastern will pursue four main research projects all cen­tered on the theme of coral reef ecology in the con­text of global change. Hel­muth will be under­water with Aquarius for two full weeks, while the rest of the North­eastern team—which includes Pat­terson, three grad­uate stu­dents, and two research tech­ni­cians sta­tioned “topside”—will be con­ducting shorter-​​term dives throughout that same period. In addi­tion, Stephen W. Director, Northeastern’s provost and senior vice pres­i­dent for aca­d­emic affairs, will dive to Aquarius to visit Hel­muth and the rest of the Aquarius team. Director’s dive will be streamed live to the Boston Museum of Sci­ence, part of an ongoing edu­ca­tional out­reach com­po­nent of Northeastern’s part of the mission.

In the first research project—part of an existing National Sci­ence Foun­da­tion grant to Patterson’s lab—the North­eastern team will create elec­trical models of two dif­ferent types of coral bodies and their respec­tive responses to stress. Data will be col­lected throughout the two-​​week-​​long stay at Aquarius.

Sec­ondly, the team will be col­lecting “pea-​​sized” tissue sam­ples from 14 coral species for the Ocean Genome Legacy, Northeastern’s partner and a pub­licly acces­sible biorepos­itory of DNA sam­ples from ocean species around the globe that is now located at Northeastern’s Marine Sci­ence Center.

One of those species, the barrel sponge, can live for more than two mil­lennia and is the focus of a third project, which will be led by Patterson’s and Helmuth’s labs. The researchers will use state-​​of-​​the-​​art mon­i­toring instru­ments to track the flow of energy through the sponges in order to examine the non-​​lethal effects of cli­mate change on the organism.

In the fourth project, the team will col­lect spec­i­mens of zoo­plankton from throughout the water column 24 hours a day. Global change has been a pri­mary driver of coral reef decline over the last half cen­tury, and many studies have shown that corals weather these effects better when they have access to food in the form of animal plankton. Cur­rently, no good snap­shot of zoo­plankton bio­di­ver­sity in these areas has been gath­ered to estab­lish a base­line for exam­ining the effects of future global change on this species set.

The Marine Sci­ence Center has a lot of expe­ri­ence in coral ecology,” Pat­terson said. “We’re a global uni­ver­sity that is strongly focused on sus­tain­ability as evi­denced by our Urban Coastal Sus­tain­ability Ini­tia­tive. Here’s an impor­tant system to get long term data on the health of corals and coral reefs, which is obvi­ously influ­enced by human actives on the land and sea.”