Geoff Trussell

The rules of the water

by Greg St. Martin

This summer, an inter­dis­ci­pli­nary research team led by Marine and Environmental Sciences pro­fessor Geoff Trussell will study com­mu­nity orga­ni­za­tion and con­nec­tivity of rocky inter­tidal habi­tats throughout the Gulf of Maine. The project is intended to help inform the devel­op­ment of pre­dic­tive eco­log­ical models that can be used to improve how these ecosys­tems are man­aged and preserved.

The study’s goal is to iden­tify common rules gov­erning com­mu­nity orga­ni­za­tion that can be scaled up to explain broad bio­geo­graphic vari­a­tion across the Gulf of Maine. The gulf spans 36,000 square miles, including the shores of Northeastern’s Marine Sci­ence Center and extending as far north as the Cana­dian provinces of Nova Scotia and New Brunswick.

July 15, 2014 - Geoff Trussell is Professor and Chair of the Marine and Environmental Sciences Department (MES) at the Northeastern University Marine Science Center in Nahant, MA.

Geoff Trussell is Professor and Chair of the Marine and Environmental Sciences Department and director of the Marine Science Center in Nahant, MA.

“Until you get a gen­eral under­standing of rules that may apply across all com­mu­ni­ties, it’s going to be very dif­fi­cult to under­stand how to manage them,” said Trussell, who is director of Northeastern’s Marine Sci­ence Center in Nahant, Mass­a­chu­setts, and chair of the Depart­ment of Marine and Envi­ron­mental Sciences.

The research study — which is sup­ported by a $1.7 mil­lion award from the National Sci­ence Foundation’s Bio­log­ical Oceanog­raphy program — has broad impli­ca­tions. According to Trussell, waters in the Gulf of Maine are warming at a faster rate than nearly all of the world’s other salt­water ocean basins. Plus, he said, they’re being increas­ingly invaded by non-​​native species.

The researchers will survey 22 sites throughout the Gulf of Maine to eval­uate the vari­a­tion in fac­tors such as species com­po­si­tion, food avail­ability, wave energy, and other envi­ron­mental stres­sors and ana­lyze what is dri­ving the dif­fer­ences between these coastal marine com­mu­ni­ties. Trussell noted that past studies have his­tor­i­cally focused on the southern Gulf of Maine. Theirs, he said, will be the first to focus on the entire Gulf in order to better under­stand the var­ious fac­tors dri­ving indi­vidual com­mu­nity dynamics.

Earth and Environmental Sciences Assistant Professor Tarik Gouhier

Marine and Environmental Sciences Assistant Professor Tarik Gouhier

Trussell is the lead prin­cipal inves­ti­gator on the project, which brings together experts in ecology, pre­dic­tive mod­eling, and marine com­mu­nity con­nec­tivity. The team includes co-​​principal inves­ti­gator Tarik Gouhier, an assis­tant pro­fessor whose lab in Nahant focuses on devel­oping dynam­ical models to under­stand eco­log­ical and envi­ron­mental processes; stu­dent researchers from the MSC; and researchers from the Uni­ver­sity of Mass­a­chu­setts Boston, the Downeast Insti­tute, and the Uni­ver­sity of Maine.

Trussell noted that his former doc­toral stu­dent, Eliz­a­beth Bryson, played a key role in research pub­lished last year in the journal Eco­log­ical Mono­graphs showing dis­tinct dif­fer­ences in how marine com­mu­ni­ties are struc­tured in the northern Gulf com­pared to the south. These find­ings, he added, pro­vided com­pelling evi­dence that more work needed to be done to inform ade­quate scaling of local rules that per­tain to the entire Gulf of Maine.

“Here you have com­mu­ni­ties that super­fi­cially look sim­ilar,” Trussell said. “They con­tain the same species and so on, but they have dif­ferent processes oper­ating to deter­mine how they recover from dis­tur­bance and how they are ulti­mately organized.”

These dif­fering com­mu­nity dynamics are vast and com­plex. For many com­mu­ni­ties, coastal oceanog­raphy is a major factor, as it influ­ences the delivery of species from one com­mu­nity to another. The abun­dance of cer­tain species is also dic­tated by water tem­per­a­ture. Another factor is seaweed—in the northern Gulf it is a crit­ical marine resource for har­vesters and in the south it plays a key role in buffering many species from the heat stress.

Trussell added that inva­sive species—and how warming waters enhance their establishment—play a huge role in how these com­mu­ni­ties are organized.

“If we’re going to be able to pre­dict those impacts, we really need to under­stand how these com­mu­ni­ties work across this broad scale,” he said.

Originally published in news@Northeastern on June 8, 2015.

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