On the east coast of our country and especially in this area, we are surrounded by and close to water. The Chesapeake Bay is one of the largest estuaries in North America, some say the largest, and one of the most productive in the world. An estuary is a body of water with a mix of fresh and saltwater. The distance of its shoreline, over 11,000 miles, is so convoluted that if it were stretched out, it has been said it would extend from Maine to Florida. Water flows from the mountains in several states through the tributaries, rivers, streams and smaller bays into the Chesapeake Bay on its way to the ocean at Virginia Beach.
Water can be mesmerizing like watching an open fire. Its color can change with the weather, time of day and location. Piney forests have waters that are tinted brown with tannic acids usually from white cedars and naturally occurring iron. The waters in the tropics are often a clear soft aqua with crystal white or pastel sand. The water in the bay and its surrounding estuaries and tributaries tells a story with its changes of color.
Clarity and Color
Water clarity is defined as the measure of the amount of penetration of light through water. That light brings life to the creatures that live in the lower depths of the water. The Bay is relatively shallow with a depth of an average of 21 feet. Areas monitored in 2008 were not able to support life at those depths and were labeled “dead zones”. If nitrogen from runoff is infused into the water, it acts as a fertilizer. Plant material called algae and microscopic phytoplankton growth increases at a rapid rate. The increased population of algae and phytoplankton eventually dies. The decaying matter produces bacteria which use oxygen in the decomposition process. This makes the oxygen unavailable for other sea life. The water clarity decreases with
the abundance of these plants thus blocking the sunlight’s penetration to greater depths.
The color of the water is an indicator of its health. Water in the tributaries of the bay is a green hue. The water generally is clearer in the wintertime when microscopic plant material is no longer living. In the spring as the waters warm, swirls of pollen can be seen on the water from the abundant trees lining the shores. Color and clarity change with the increased temperature of the water.
There has been a conscious effort to increase the presence of oysters in these waters. Many docks have oyster floats attached and oyster farming is increasing. Their numbers are important not just because they are delicious. A mature oyster of 1-2 years of age filters bacteria and toxins from the water of between 45 and 65 gallons a day.
A healthy ecosystem has its own checks and balances. Living organisms such as the oyster help to filter the water. Algae and phytoplankton supply food for aquatic creatures. Salinity varies according to rainfall and drought. Organisms die, decay and produce minimal bacteria.
It can get out of balance when nitrogen or other pollution creates excess algal or phytoplankton growth. The bacteria’s presence in the decaying process of these plants when they die uses oxygen which is otherwise available to aquatic life. Color can be influenced by many factors including: pollution through technology, agriculture, overfishing, irrigation that changes the salinity, farming practices and nitrogen runoff from lawns and erosion. When the effect of this pollution impacts the water, the color and clarity are changed. “Mahogany” or “Red” as well as blooms of green, yellow and brown tides can be visualized as a result from large “blooms” of algal or plankton plant material. Some algal blooms produce toxins as well. Anthropogenic influence, the human impact on the environment, can make a difference. The health of the bay is important. Watermen are a valuable resource for our water communities and supply seafood to extensive markets. Commercial fishermen make their livings on the water, and recreational usage is expanding yearly.
So What Can Be Done?
The Chesapeake Bay is shared by the states of Virginia and Maryland. The University of Maryland Center for Environmental Science studies the health of the bay. The result of these studies helps lawmakers set policy. Monitoring the color of the water is similar to the medical profession. If the color is not right or has changed, perhaps it is indicating declining health.
VIMS (Virginia Institute of Marine Science), the graduate school of the College of William and Mary, is a center for extensive research and monitoring of our waters. Located on the York River in Gloucester, many of their programs are open to the public. They are responsible for research, education and advisory services. VIMS is among the largest marine research and education centers in the United States.
The Chesapeake Bay Program, Enhanced Shallow Water Quality Monitoring Program oversees monthly water monitoring. This program has measured water temperature, specific conductance, dissolved oxygen, PH, turbidity, water depth and aquatic life since 1995. There are water quality stations in the York, Rappahannock and Potomac Rivers. Algal blooms are monitored as well. Starting in 2002 inorganic nutrients such as ammonium, nitrate, nitrite, ortho-phosphate, total dissolved nitrogen, phosphorus and chlorophyll have been monitored at reserve sites.
DCR (Department of Conservation and Recreation) monitors nutrient management and soil and water conservation. Soil and Water Conservation Districts play a pivotal role in preventing runoff. They have been involved in this process since the 1930s with planning and development resources. With 60% of the commonwealth draining into the bay, this bears monitoring.
The Virginia Department of Health’s Waterborne Hazards Control Program monitors our water for algae blooms, some toxic and some not. They are very helpful and knowledgeable about any blooms you may notice and can assist in supplying the public with accurate information concerning our water
and its health.
One of the reasons that water is so mesmerizing is the spectacular and varying views it creates. A reflection is simply the change in direction of a light ray as it enters or bounces off of a medium, in this case, the water. Water is a good absorber of light when the sun is directly overhead. This causes the water to look dark. Sunrise and sunset, when the light is lower in the sky, creates a greater angle and more reflection. When the wind ripples the surface even more surfaces are available to reflect the light causing the “diamond” effect.
Mist or fog on the water, with its water vapor, further dissipates the reflection and softens the color, often showing a multicolored haze effect. This is the same phenomenon that causes rainbows, simply the water vapor reflecting light. With 70% of our earth covered with water, reflection has a profound influence on global temperatures.
Light is reflected off of the water in a differing way when the water is frozen. That explains why tropical oceans remain warmer as the sun’s level is consistently higher in the sky. The heat energy of the rays are absorbed by the water, thus warming it. While the ice in northern areas of the world, where the sun is on a greater angle closer to the horizon, causes less absorption of the warming rays and colder temperatures. Basically, radiation is the absorption of the light, thus warming, and reflection is when light is bounced
off the surface.
Treat yourself to a dark velvet night by the water. Look up at the multitude of sparkling stars. Look down and be awed by that view reflected by the water. Take time to spend an evening with the sunset lighting up the water like a rainbow. Or get up early and marvel at the colors of the dawn painted on the water. Breathe in the newness of spring as pollen drifts in the tide and delight in the darkness of winter as the ice adds a new dimension to the color of our water.
With thanks for photographic assistance and for further information please contact
David Malmquist Director of Communications
Virginia Department of Health Waterborne hazards control program VDH Department of Epidemiology
Department of Conservation and Recreation