Bay dead zone ex­pected to be larger this year

Heav­ier nu­tri­ent load from Susque­hanna River is the cul­prit

Maryland Independent - - Front Page - By DANDAN ZOU dzou@somd­ Twit­ter: @Dan­danEn­tNews

Sci­en­tists pre­dict the size of a dead zone in Chesapeake Bay this sum­mer to be at nearly 1.9 cu­bic miles — larger than the aver­age of 1.7 cu­bic miles recorded in the past three decades.

This year’s dead zone is equiv­a­lent to 3.2 mil­lion Olympic-size swim­ming pools, ac­cord­ing to a press re­lease from the Univer­sity of Mary­land Cen­ter for En­vi­ron­men­tal Sci­ence.

Dead zones, also known as hy­poxic zones, are caused by ex­ces­sive nu­tri­ent pol­lu­tion, pri­mar­ily from hu­man ac­tiv­i­ties such as agri­cul­ture and waste­water, ac­cord­ing to the Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion.

Ex­ces­sive nu­tri­ents can stim­u­late an over­growth of al­gae, which then sinks and de­com­poses in the wa­ter. That process uses oxy­gen in the wa­ter, leaves ar­eas of wa­ter with low oxy­gen and causes fish and other marine life to die or leave the area.

Sci­en­tists at­trib­uted this year’s higher-than-aver­age dead zone size to above-aver­age nu­tri­ent load from the Susque­hanna River in New York and Penn­syl­va­nia this spring, the univer­sity’s re­lease said.

“Although the higher fore­casts for this sum­mer seem to buck a re­cent trend to­ward lower anoxic vol­umes in Chesapeake Bay, they are con­sis­tent with known links be­tween high river flows and oxy­gen de­ple­tion,” said Jeremy Testa, as­sis­tant pro­fes­sor at the Univer­sity of Mary­land Cen­ter for En­vi­ron­men­tal Sci­ence’s Chesapeake

The Susque­hanna River car­ried more than 80 mil­lion pounds of ni­tro­gen into the bay, slightly larger than the long-term aver­age, the re­lease said.

The anoxic por­tion of the zone, which con­tains no oxy­gen at all, is ex­pected to be 0.35 cu­bic miles in early sum­mer, grow­ing to be 0.49 cu­bic miles by late sum­mer, the re­lease said. Both of which are at or slightly above aver­age.

“The fore­cast is a re­minder that the im­prove­ments such as we saw last year are sub­ject to Bi­o­log­i­cal Lab­o­ra­tory. re­ver­sal de­pend­ing on weather con­di­tions,” said Don Boesch, pres­i­dent of the Univer­sity of Mary­land Cen­ter for En­vi­ron­men­tal Sci­ence, in a re­lease. “Two steps for­ward, one step back.”

Mon­i­tory re­ports re­leased ear­lier this year showed the bay’s health slightly im­proved.

“This un­der­scores the crit­i­cal im­por­tance of con­tin­ued in­vest­ments by fed­eral agen­cies in sci­ence and mon­i­tor­ing as the states con­tinue to im­ple­ment the bay’s pol­lu­tion diet,” Boesch said.

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