Northeastern researchers investigate rules of the water

A team of Northeastern University interdisciplinary researchers, led by professor Geoff Trussel, has received a $1.7 mil­lion award from the National Sci­ence Foundation's Bio­log­ical Oceanog­raphy program to study com­mu­nity orga­ni­za­tion and con­nec­tivity of rocky inter­tidal habi­tats throughout the Gulf of Maine.

The project has ties to the university's larger Urban Coastal Sustainability Initiative, a cutting-edge science and policy center committed to generating research and developing solutions toward the sustainability of city coastal regions, and is intended to help inform the devel­op­ment of pre­dic­tive eco­log­ical models that can be used to improve how these ecosys­tems are man­aged and preserved and has 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 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.

"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 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.

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 Marine Sci­ence Center; 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.

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