Ex­pect ‘sig­nif­i­cant’ al­gae bloom on Lake Erie

The Hamilton Spectator - - CANADA & WORLD - JOHN FLESHER

TRA­VERSE CITY, MICH. — A “sig­nif­i­cant” harm­ful al­gae bloom is ex­pected to form in western Lake Erie this sum­mer, though it prob­a­bly won’t be as large as some pre­vi­ous for­ma­tions that posed health risks and ham­pered tourism, sci­en­tists said Thurs­day.

The Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion and re­search part­ners re­leased their an­nual al­gae fore­cast for the shal­low­est and warm­est of the Great Lakes, where mas­sive al­gae for­ma­tions are a re­cur­ring threat to the en­vi­ron­ment and the econ­omy. Toxic con­tam­i­na­tion from a 2014 bloom prompted a two-day shut­down of tap wa­ter sys­tems for 400,000 peo­ple in Toledo, Ohio, and south­east­ern Michi­gan.

“It’ll be large, green and ugly and will cause the same kinds of is­sues it has in the past for char­ter boat cap­tains try­ing to get peo­ple out to fish,” said Don Scavia, a Univer­sity of Michi­gan sci­en­tist.

It’s un­likely to cre­ate an­other drink­ing wa­ter cri­sis like the one three years ago. It resulted from a rare com­bi­na­tion of fac­tors, in­clud­ing high lev­els of tox­ins gen­er­ated by the bloom and its lo­ca­tion near Toledo’s off­shore wa­ter in­take fa­cil­ity, NOAA oceanog­ra­pher Rick Stumpf said. Mon­i­tor­ing has been stepped up since then and early-de­tec­tion de­vices in­stalled, he added.

Still, the sit­u­a­tion un­der­scores the need to re­duce the flow of nu­tri­ents into the lake that feed al­gae and sim­i­lar bac­te­ria, pri­mar­ily from farms, but also sewage treat­ment plants and other sources, Stumpf said.

Re­searchers have de­vel­oped a scale for rat­ing the sever­ity of a bloom based on how much al­gae it con­tains over a sus­tained pe­riod. They pre­dict this year’s will reg­is­ter a score of 7.5, though it could range any­where from 6.5 to 9. A rat­ing above 5 in­di­cates a po­ten­tially harm­ful level, mean­ing such blooms could do dam­age by pro­duc­ing tox­ins or suck­ing enough oxy­gen from the wa­ter to cause fish kills.

When they de­vel­oped the scale, re­searchers thought the max­i­mum score would be a 10. A 2011 bloom reached that mark and a 2015 bloom ex­ceeded it, reg­is­ter­ing a 10.5 as the big­gest on record. It’s worth not­ing that a bloom’s size doesn’t nec­es­sar­ily re­flect its tox­i­c­ity.

The 2016 bloom rated a mild 3.2, which ex­perts cred­ited largely to dry weather. Spring and sum­mer rain­fall plays a key role in bloom for­ma­tion by wash­ing fer­til­iz­ers from crop­lands into streams and rivers that flow into the lake. Phos­pho­rus in chem­i­cal fer­til­iz­ers and live­stock ma­nure pro­motes al­gae growth.

The weather has been sig­nif­i­cantly wet­ter this year, and the bloom size is ex­pected to re­flect that.

Re­cent al­gae for­ma­tions in western Lake Erie have taken shape in late July and grown big­ger in early Au­gust. A sim­i­lar pat­tern is ex­pected in com­ing months.

“A bloom of this size is ev­i­dence that the re­search and out­reach ef­forts cur­rently un­der­way to re­duce nu­tri­ent load­ing, op­ti­mize wa­ter treat­ment, and un­der­stand bloom dy­nam­ics need to con­tinue,” said Christo­pher Winslow, di­rec­tor of the Ohio Sea Grant Col­lege Pro­gram.

HARAZ N. GHANBARI, THE AS­SO­CI­ATED PRESS

An al­gae bloom cov­ered Lake Erie in 2014. Sci­en­tists ex­pect sim­i­lar prob­lems this year.

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