climate change

Mapping Rising Seas

~ slubkin ~ Leave a comment

According to U.N. Secretary-General Ban Ki-moon, climate change is “one of the most crucial problems on Earth”. That’s because climate change means more than just rising temperatures and shrinking glaciers. Climate change also means shifts in weather patterns, stronger storms, longer and more severe droughts, changes in the distribution of agricultural pests and diseases, increased wildfire risk, greater ocean acidity, and sea level rise.

For my semester project, I chose to model sea level rise at Wallops Island, Virginia. I visited Wallops Island in April as part of the STEM Takes Flight Sea Level Rise/Invasive Species Service Learning Course. I will write about that experience in another post.

Wallops Island is a barrier island off Virginia’s Eastern Shore. It is a wildlife refuge and home to NASA’s Wallops Flight Facility, which is NASA’s center for the management and implementation of suborbital research programs. Because of Wallops Island’s location, it is especially vulnerable to sea level rise.

Satellite measurements (NOAA, 2016) show that since 1992, global sea level has been rising at an average of 0.11 inches per year. However, in Virginia’s barrier islands, sea level is rising at twice that rate, an average of about 0.22 inches per year (NOAA, 2016).

When you think of a quarter inch, it really doesn’t seem like very much.Why is this a big deal?

In places like Wallops Island where elevation is close to sea level, small amounts of sea level rise can result in large losses of land. At the current rate of sea level rise, most of the island will be gone by 2040.

Here are some maps I created of land loss on Wallops Island. In this image, land is represented as black and water is represented in color.

Sea Level Rise

Sea level rise is not a new problem for Wallops Island. Land in the Chesapeake Bay area is subsiding or sinking because the Earth is still adjusting to the recession of the glaciers from the last ice age about 12,000 years ago. However, land subsidence increases the rate of relative sea-level rise, and this is why the Virginia coasts have the second highest level of sea level rise in the U.S.

Because of subsidence, the coastline of Wallops Island has moved steadily shorewards from 1851 (earliest data available) to 1962.  However, since 1962, NASA interventions, including a sea wall completed in 2012, have restored much of the shoreline. The 2014 and 2011 coastlines showed the least encroachment because of these interventions.

Even with the sea wall, constant maintenance is required to prevent the beaches from losing 10 to 22 feet of coast to erosion each year.Coastlines

As the Earth warms, rates of sea level rise will increase. It will become harder and more expensive for NASA to counteract the loss of land and protect its facilities.

For a video and more information about sea level rise, Wallops Island, and the methods used in my project,  visit my online story map.

 

Harmful Algal Blooms – Part 1: Who Cares About Harmful Algal Blooms?

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It’s a beautiful day in Virginia. The sun is shining, the birds are singing and the water is a beautiful shade of brownish green…

Harmful Algal Bloom
Source: Chesapeake Bay Foundation

The “lovely” color of the water is a harmful algal bloom. An algal bloom is an overgrowth of phytoplankton –  tiny, photosynthetic organisms that live in the water. A harmful algal bloom or HAB is an algal bloom that has some kind of negative effect on other organisms.

In Virginia, harmful algal blooms occur between May and September when the water is warm and full of nutrients like phosphorous and nitrogen – the same nutrients used to fertilize plants. Some of these nutrients come from industry and sewage treatment, but many nutrients are washed into the water when rain falls on farms and yards.  Warm, wet summers are great for plants and for harmful algal blooms.

Algal blooms discolor the water and produce noxious odors. They also block the sunlight that is needed by underwater plants and keep filter feeders like oyster from being able to obtain food. When the phytoplankton die and decompose, they remove large quantities of dissolved oxygen from the water and create anoxic dead zones. The result is massive fish kills because fish, oysters, clams, crabs, and other organisms can’t get the oxygen they need.

Source: Chesapeake Bay Foundaton
Source: Chesapeake Bay Foundation

Scientists in Virginia are especially concerned about two species: Cochlodinium polykrikoides and Alexandrium monilatum. Cochlodinium polykrikoides is native to Virginia. Alexandrium monilatum is an invasive species that wasn’t found north of Florida until 2007. It now occurs regularly in Virginia’s rivers.

Both these species produce red tides, like the bloom in the picture below. They also produce toxins that can kill fish and cause birth defects in shellfish. These toxins may also cause illness in humans.

Image from Virginia Institute of Marine Science (VIMS)
Source: Virginia Institute of Marine Science (VIMS)

HABs are a public health problem. They are also an economic problem because a large bloom can have a big impact on Virginia’s fishing industry and tourist industry. So, Virginia has a Harmful Algal Bloom Task Force. The task force includes representatives from the Virginia Institute of Marine Science (VIMS), the Marine Resource Commission, the Department of Environmental Quality (DEQ), Old Dominion University (ODU) and the Virginia Department of Health. These agencies work together to monitor Virginia’s waters for harmful algal blooms and to respond to bloom events. VIMS and ODU do research on harmful algal bloom species and the biological and environmental conditions that contribute to bloom growth.

HABmap
Virginia Harmful Algal Bloom Surveillance Map 

But, harmful algal blooms aren’t unique to Virginia. Large blooms and dead zones have also been recorded in the Great Lakes, the Gulf of Mexico, the St. Lawrence Estuary, the Oregon Coast, Monterey Bay, the Baltic Sea and Florida. The total economic impact of harmful algal blooms in the U.S. is estimated at $100 million per year.

Last year, Congress reauthorized and expanded the Harmful Algal Blooms and Hypoxia Research and Control Act of 1998. This act provides funding for the study and monitoring of HABs in U.S. waters.

As climate change causes waters to warm, harmful algal blooms are expected to increase in both frequency and severity. More and more water will be affected. So, who cares about harmful algal blooms? We all should care.

Next week: Harmful Algal Blooms – Part 2: Monitoring Harmful Algal Blooms

Edited on 11/20 to add map.