Chesapeake Bay dead zone this summer worst since 2014

Chesapeake Bay dead zone this summer worst since 2014

In June, federal scientists predicted a bigger-than-average oxygen-deprived dead zone in the Chesapeake Bay this summer, and it turns out they were right.

Researchers with the Virginia Institute of Marine Science who study bay hypoxia announced Monday that the total amount of dead zones this summer was the worst since 2014, and a 10 percent increase over last year.

This, despite a drop in the overall duration and maximum extent of dead zones compared with 2016.

“The time period from beginning to the end was just a little shorter than usual,” said VIMS marine biologist Marjorie Friedrichs in a phone call Monday. “But the peaks — when it was bad, it was really bad.”

VIMS, based in Gloucester Point, has used a real-time, three-dimensional forecast model since 2014 to gauge various hypoxia metrics in the bay, including volume and duration, the average summer volume and the cumulative or total amount in a given year, generated by adding up each day’s hypoxic volume.

Tallying up the daily volume, researchers estimated there were 919 cubic kilometers of hypoxia during 2017. This is larger than the 833 cubic kilometers in 2016, 757 cubic kilometers in 2015 and 918 cubic kilometers in 2014.

chesapeake-bay-dead-zone-this-summer-worst-since-2014 photo 1 Robert Ostermaier / HANDOUT Drone photos of algae blooms in the York River from a drone being used by Virginia Institute of Marine Science,- Original Credit: Virginia Institute of Marine Science- Original Source: Virginia Institute of Marine Science Drone photos of algae blooms in the York River from a drone being used by Virginia Institute of Marine Science,- Original Credit: Virginia Institute of Marine Science- Original Source: Virginia Institute of Marine Science (Robert Ostermaier / HANDOUT)

Hypoxia occurs when large amounts of nitrogen — mostly from farm fertilizers — is swept into the vast watershed, typically by rain events, and ends up in the bay.

There, it fuels explosive growths of algal blooms in the Chesapeake and its major tributaries. As the blooms decay, they suck up oxygen from the water column and create dead zones that are lethal to blue crabs, striped bass and other marine life.

The concentration of dissolved oxygen in ocean water is typically between 7 and 8 milligrams per liter, said VIMS. Anything below 4 milligrams will begin to affect marine organisms.

Waters with less than 0.2 milligrams are called anoxic and can’t support most forms of life; those with no measurable dissolved oxygen are hypoxic.

In June, NOAA warned that heavy rains in the northern part of the watershed from January to May spelled trouble for the bay this summer, sweeping even more nitrogen than usual into the waterways that feed the estuary.

Much of that nitrogen came from the Susquehanna, the bay’s biggest tributary and a notoriously polluted river running through New York, Pennsylvania and Maryland before it hits the Chesapeake.

Robert Magnien, director of NOAA’s Center for Sponsored Coastal Research, said at the time that “great strides” have been made to reduce nutrient pollution in the watershed — but not enough.

“More work needs to be done to address nonpoint nutrient pollution from farms and other developed lands to make the bay cleaner for its communities and economic interests,” Magnien said.

chesapeake-bay-dead-zone-this-summer-worst-since-2014 photo 2 CAPTION

Video of the harmful algal bloom in the York River, a major tributary of Chesapeake Bay. Samples collected and video footage captured by professor Kim Reece of the Virginia Institute of Marine Science, VIMS lab specialist Bill Jones, and colleagues in the Marine and Aquaculture Molecular Genetics lab at VIMS on August 30, 2012. 

Video of the harmful algal bloom in the York River, a major tributary of Chesapeake Bay. Samples collected and video footage captured by professor Kim Reece of the Virginia Institute of Marine Science, VIMS lab specialist Bill Jones, and colleagues in the Marine and Aquaculture Molecular Genetics lab at VIMS on August 30, 2012. 

chesapeake-bay-dead-zone-this-summer-worst-since-2014 photo 3 CAPTION

Boeing Co. and SpaceX are bringing back gumdrop-shaped capsules in developing spacecraft under NASA contracts to ferry astronauts to the International Space Station. (Sept. 15, 2017) (Sign up for our free video newsletter here http://bit.ly/2n6VKPR)

Boeing Co. and SpaceX are bringing back gumdrop-shaped capsules in developing spacecraft under NASA contracts to ferry astronauts to the International Space Station. (Sept. 15, 2017) (Sign up for our free video newsletter here http://bit.ly/2n6VKPR)

According to VIMS, the early spring loads were but one factor in this year’s dead zone activity.

Also in play were relatively strong winds in the first half of May, which delayed the onset of hypoxia compared to previous years. In June, hypoxia increased “very rapidly” and peaked unusually high at mid-month.

Windy periods kicked up in late June through August, dropping the overall amount of hypoxia from earlier peaks created in part by record-breaking temperatures of 100-plus degrees in mid-summer.

VIMS operates its baywide forecast model with Anchor QEA, a Seattle-based scientific and engineering consulting firm where managing scientist Aaron Bever is a VIMS graduate.

Their report comes on the heels of a report from Maryland released last month that found that, at least for a portion of Maryland’s mainstem of the bay, dissolved oxygen levels were better than average for late August.

But the Maryland Department of Natural Resources cautioned that its results were incomplete due to bad weather conditions, which precluded assessing the bay south of the Potomac River to the Virginia state line.

Contact Dietrich at 757-247-7892 or tdietrich@dailypress.com. Follow on Twitter at DP_Dietrich

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    Article Chesapeake Bay dead zone this summer worst since 2014 compiled by www.baltimoresun.com

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