Bay Grasses Decline to Lowest Levels in More than a Quarter Century

Underwater grasses in the Chesapeake Bay declined last year to the lowest levels in more than a quarter century, in part because of storms in 2011 that flushed runoff pollution into the estuary, grassesaccording to scientists with the Chesapeake Bay Program. Global warming is also cooking a temperature-sensitive species of grass in the southern Bay.

Bay grasses declined 21 percent, to 48,191 acres, between 2011 and 2012, Dr. Robert Orth, an aquatic vegetation expert and Professor of Marine Science at the Virginia Institute of Marine Science, said during a press conference this morning.

Chesapeake Bay Foundation President Will Baker said the decline is a sobering reminder that extreme weather can set back recovery of the Bay. He said it is also a reminder that we need to focus on the elements we can control, especially reducing pollution to the Bay.

“In 2012, underwater grasses suffered a one-two punch,” Baker said. “Extreme heat in 2010 led to a significant decline in grasses in the lower Bay in 2011. And 2011 was a very wet year, beginning with heavy spring rains and ending with Hurricane Irene and Tropical Storm Lee, creating poor conditions for growth in 2012.”

An accurate picture of the Bay’s health is more complex than just the grass numbers, with improvements recently in other areas. The Chesapeake last year experienced the smallest low-oxygen “dead zone” since 1985. Oysters are showing improved resiliency, and striped bass are at significantly higher levels now than during the 1970s and early 1980s.

Dr. Orth and Lee Karrh, Senior Biologist at the Maryland Department of Natural Resources and chair of the Chesapeake Bay Program’s Submerged Aquatic Vegetation Work Group, said the solution to the recent problems with the Bay grasses is for regional governments to reduce pollution to meet EPA pollution limits for the estuary. These limits (also called the Bay “Total Maximum Daily Load” or TMDL) require the implementation of state plans to reduce pollution that are a blueprint for saving the Bay.

“The TMDL is the elephant in the room,” said Dr. Orth. “And how to deal with (the EPA pollution limits) on a local basis is what everyone is talking about.”

Karrh agreed. “The best thing we can do is to improve water quality,” to restore the Bay’s grasses, he said.

According to the Bay Program scientists, a species of aquatic vegetation common in the southern bay -– eelgrass -– is being killed by warming Bay waters caused by climate change. Eelgrass requires relatively cool waters to survive.

Grasses in the lower and middle Bay were subjected to excessively warm waters in the summer of 2010. Poor water clarity –- caused in part by algal blooms likely fed by nitrogen and phosphorus pollution — since then has kept the grasses from rebounding, according to the Bay Program scientists.

Grasses in two other areas of the Bay showed notable resilience. In the far northern part of the Bay, the grass beds at the mouth of the Susquehanna River remained robust and dense, although they also declined somewhat, according to the Bay Program scientists. In Virginia, grasses in the James River continued to increase.

The Bay Program yesterday unveiled new online maps that people can use to track how underwater grasses have changed in abundance and location over the last three decades. To view it, click here.

By Tom Pelton Chesapeake Bay Foundation

(Photo from Chesapeake Bay Program)

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Eroding Bay Islands Could Be Helped by Experimental Buoys

islandWith islands in the Chesapeake Bay slowly vanishing beneath the waves because of rising sea levels and sinking land, a company plans to build experimental buoy systems to  reduce erosion in three locations this year, including on historic Tangier Island, Virginia.

The Glen Burnie, Maryland-based Murtech plans to use an innovative design tested in the labs of the U.S. Naval Academy by Dr. Michael E. McCormick, a pioneer of wave energy research and former Chairman of the Department of Naval Systems Engineering, who is also a consultant for Murtech.

This summer, the company plans to install 53 buoys –- the largest, 10 feet in diameter –- in front of the harbor of Tangier Island (an example of one of the devices is shown at right).  Tangier harbor’s western entrance has been widened by storms and erosion in recent years, allowing large waves to roll in and smash the crab shacks and piers of watermen. The buoys will have fins on their sides, and are designed to create interference with the waves and reduce their size and power. Similar systems are being planned for Barren Island, in Maryland, and Aberdeen Proving Grounds, in the northern Chesapeake Bay, according to Murtech.buoy

“The idea is to reduce the wave energy going into the channel,” said Dr. McCormick.  “And we hope to also help them stabilize the shoreline.”

Researchers say climate change is driving up water levels in the Chesapeake Bay at a rate of three or four millimeters a year.  Many islands in the Bay are eroding, including Holland Island (pictured at the top of this story) in part because the land is also settling due to natural geological shifts.

Tangier Island (pictured at right) is ground zero for people who want to see the real-work impact of sea level rise. This remote fishing community of 470 people looks like a town out of an earlier century –- with Victorian homes, simple cottages, and a general store connected by walking paths and bridges. Because there are no roads built for cars, many residents get around on golf carts.

The streets frequently flood during storms and high tides. Large puddles -– ponds, really -– linger to dominate lawns.  Graves are weighted down with cement slabs, so the frequent flood waters don’t disturb them. Tangier’s public school was built on stilts, and then had to be raised even higher because the waters kept bumping up against the floorboards.

Ken Castelli , Director of the Tangier History Museum, said the island loses several acres of land every year to erosion.

“The island used to be twice as big when Captain John Smith was here, in 1608,” Castelli said.  “Even up until the early 20th century, the island was still relatively large. And then in the last 60 years or so, the island has finally whittled away enough to where it looks like (the erosion) is starting to speed up, because we are getting smaller and smaller.”

The island’s population has fallen by two thirds since the 1930s. Those who do remain are determined not to give up on their quiet, close-knit community.

“We do have quite a bit of flooding, but we just take it in stride,” said  Tangier Mayor James “Ooker” Eskridge, a waterman (pictured at left).

As he motored his work boat out of the harbor on a recent morning, he passed a section of town called Oyster Creek that is now completely beneath the waves.

“You could explore the bottom there and find the bricks from the homes – the chimneys and old bottles, pottery, different things,” he said, pointing out at an expanse of water near a channel marker. “That’s where the community used to be.”

tangierIn addition to the experimental buoy system to protect the Island, the federal and state governments are planning to build a 430-foot-long stone jetty beside the harbor at a cost of about $4.1 million.

“We are willing to try anything,” Eskridge said, passing crab shacks that have been damaged by waves. “When are losing your island to erosion, we’re not picky what we get.”

Back on shore, I called an engineer to ask: can buoys and rocks really do much against the rising sea?CBF boat

“That’s a very good question, Sir,” replied Larry Ives, leader of the Tangier Island jetty construction project with the U.S. Army Corps of Engineers.  “Can they stop it?  Probably not… Can they stave it off for an extended period of time? Yes, sir, they can, until we can come up with some other alternatives.”

The goal is to help the Tangier Islanders hold onto their historic community for as long as they possibly can, with the help of a little Naval Academy innovation and Army Corps muscle.
Tom Pelton is a Senior Staff Writer for The Chesapeake Bay Foundation

(Photo of Holland Island at top by Dave Hartcorn/CBF; photo of buoy and contract worker Hunter Stearns from Murtech/Michael McCormick;Tangier Island by CBF; Mayor James Eskridge by author.)

 

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