Sci­en­tists: Bay may con­trib­ute more to global warm­ing

Meth­ane con­cen­tra­tion higher than ex­pected

Maryland Independent - - Community Forum - By TA­MARA WARD tward@somd­ Twit­ter: @CalRecTAMARA

Meth­ane buildup in the Ch­e­sa­peake Bay alone, if re­leased, is equal to cur­rent meth­ane es­ti­mates for all the es­tu­ar­ies in the world com­bined, ac­cord­ing to a study re­leased by Univer­sity of Mary­land Cen­ter for En­vi­ron­men­tal Science.

The re­search re­port, “Meth­ane con­cen­tra­tions in­crease in bot­tom waters dur­ing sum­mer­time anoxia in the highly eu­trophic es­tu­ary, Ch­e­sa­peake Bay, U.S.A.,” ex­plores the role of meth­ane emis­sions dur­ing dead zone and storm events and how the Ch­e­sa­peake Bay could con­trib­ute more to global warm­ing than pre­vi­ously be­lieved.

“Meth­ane in­flux is a con­se­quence of eu­troph­i­ca­tion that hasn’t been fo­cused on in the Ch­e­sa­peake Bay,” said study au­thor Laura Lapham, a pro­fes­sor at UMCES Ch­e­sa­peake Bi­o­log­i­cal Lab, in an in­ter­view.

Meth­ane, a col­or­less, odor­less, nat­u­rally oc­cur­ring flammable gas, is nor­mally un­der con­trol in es­tu­ar­ies like the Ch­e­sa­peake Bay. Meth­ane is also a green­house gas that traps heat in the earth’s at­mos­phere, caus- ing global warm­ing.

Eu­troph­i­ca­tion is the ex­ces­sive amounts of nu­tri­ents, such as phos­pho­rus and ni­tro­gen of­ten from runoff, that cause plant and an­i­mal life to die due to the lack of oxy­gen. Oxy­gen de­ple­tion is also know as anoxia. Ac­cord­ing to the study, the Ch­e­sa­peake Bay is over­whelmed with nu­tri­ents that cause pol­lu­tion lead­ing to low oxy­gen con­cen­tra­tions and meth­ane emis­sions.

Lapham and a team of re­searchers stud­ied the wa­ter at the bot­tom of the Ch­e­sa­peake Bay over the course of a sum­mer in 2013, set­ting up in­stru­ments perched above the mud that would track any signs of meth­ane be­ing re­leased into the wa­ter, ac­cord­ing to a UMCES re­lease.

Dur­ing April, meth­ane con­cen­tra­tions were low when bot­tom waters were fully oxy­genated and in­creased as dis­solved oxy­gen was de­pleted. Meth­ane con­cen­tra­tions peaked in mid-July, which could be at­trib­uted to the dis­tur­bance of sed­i­ments. Con­cen­tra­tions de­creased in early Au­gust and then re­turned to back­ground lev­els when nor­mal oxy­gen con­di­tions re­turned in late Septem­ber.

“The nat­u­ral con­sump­tion process con­trols meth­ane,” re­ported Lapham. “The ma­jor­ity is con­sumed before be­ing re­leased into the at­mos­phere.” How­ever, she ac­knowl­edges there is the pos­si­bil­ity that storms could come through and churn up the wa­ter, re­leas­ing the meth­ane, warned Lapham.

To ad­dress the prob­lem of meth­ane buildup in the wa­ter and to min­i­mize meth­ane emis­sions into the at­mos­phere, Lapham sug­gests de­creas­ing the amount of nu­tri­ents go­ing into the bay.

Mary­land, Penn­syl­va­nia and Vir­ginia are al­ready en­gaged in many ef­forts un­der­way to re­store the bay, to in­clude the up­grad­ing of waste­water treat­ment plants and the re­duc­ing of pol­lu­tion runoff from stormwa­ter and agri­cul­ture, shared Mary­land Di­rec- tor of the Ch­e­sa­peake Bay Com­mis­sion Bevin Ann Buch­heis­ter in an in­ter­view.

“The bay restora­tion ef­fort, and all the pol­lu­tion re­duc­tion prac­tices wa­ter­shed states are im­ple­ment­ing for waste­water, stormwa­ter and agri­cul­ture, are aimed at elim­i­nat­ing those very dead zones that could con­trib­ute meth­ane to the at­mos­phere, so we need to con­tinue and ac­cel­er­ate our ef­forts,” said Buch­heis­ter. “With this new in­for­ma­tion, we can also view our restora­tion ef­forts as serv­ing a dual pur­pose: restora­tion of the bay and de­creas­ing our con­tri­bu­tion to cli­mate change.”

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