Algea blooms can lead to

By Katrina Styx
August 17, 2009 – 12:31pm., Jordan Independent, Jordan, Minnesota


The hypoxia or “dead” zone in the Gulf of Mexico has been back in the news as scientists report this year’s area will be smaller but still a major issue for aquatic organisms in the coastal areas of Louisiana, Mississippi and Texas. States like Iowa are encouraging farmers to restore wetlands to reduce nutrient runoff and help shrink this hypoxia zone.       

This semimonthly column examines the issue of water through eight conversation topics.  Our goal is to look at water in the context of the Minnesota River Watershed.  

Learn how hypoxia zones form and the effects it has on aquatic organisms and other animal life, along with ways to reduce nutrients from creating these “dead” areas.  Get out to the Agroecology Summit on August 21st and check out Moonstone Farm or paddle the Pomme de Terre River.

WATER – “Hypoxia” 
Defined as low oxygen, hypoxia is usually measured as the concentration of less than 2-3 milligrams oxygen per liter of water (mg/l). Hypoxia or “dead” (refers to the risk of death for many organisms living in these areas) zones are found all over the world usually in coastal waters and have been increasing in both numbers and sizes. One the largest is found in the Gulf of Mexico, the result of excessive levels of nutrients flowing off of the landscape from farms and cities in the Mississippi River and Atchafalaya River watersheds. Excessive nutrients, in particular nitrogen, stimulates the growth of algae that can result in blooms. When the bloom of algae dies off it consumes vital oxygen from the water and can kill fish and other aquatic organisms. Even though hypoxia is primarily found in estuaries and coastal waters, it can also be a problem in freshwater lakes.   

Did You Know – “What are the effects of Hypoxia?” 
The lack of oxygen in the hypoxia zone has a direct effect on the fishery by either pushing adult fish out the area or results in a fish kill. All aquatic animals need oxygen to survive, including mussels and clams which can’t move out of a “dead” zone. Birds like herons and animals like otters that eat fish also suffer. The Ecological Society of America reports these areas may also be more susceptible to overfishing, pest outbreaks, storm damage, or other stresses. Finally, pollutants stored in the sediments can be released when there are chemical reactions between hypoxic water and bottom sediments causing additional polluting of the ecosystem.     

Water Science – “How old is water?” 
How old is the water you are drinking? Water formed on our planet millions of years ago and continues to be recycled as it moves through the hydrologic or water cycle. The water you are drinking could have been used by the dinosaurs or by your great- great- great-grandfather. Water molecules are constantly on the move because of the earth’s wind currents and climate changes. Imagine how the rain that fell across the eastern seaboard of the United States could end up falling later in the form of snow in the Alps and remain part of a glacier for a hundred years or more. Water has been in constant motion since it formed on the earth with practically the same amount as it is used over and over again.

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What Can You Do? – “Protecting Waters from Hypoxia” 
According to the Ecological Society of America, there are a number of things we can do reduce or eliminate hypoxia zones from forming in our waters. 
•Minimize use of fertilizers and manage them properly. Excess fertilizer washes off lawns and farms into streams and eventually rivers, where is travels to the ocean. It can also volatize from fields or manure lagoons into the atmosphere and be redeposited where it can wash into waterways. 
•Remove nutrients from wastewater and urban runoff before they are discharged.  These sources contribute large amounts of nutrients to areas at risk for hypoxia. 
•Reduce the amount of electricity use and number of miles driven. Power generation, either in an electrical power plant or in a car, generates nitrogen oxides (NOx).  NOx are transformed into nitrates in the air and deposited throughout the country, especially east of the Mississippi River. 
•Practice clean boating. This includes choosing boat engines that produce the smallest amount of NOx and using pumpout stations at marinas rather than discharging raw sewage into the water. 
•Preserve land adjoining rivers and streams. This land, often called a riparian buffer, can play a vital role in preventing nutrients that wash off fields and streets from reaching the rivers and coasts. Preserving wetlands also helps keep nutrients out of rivers, estuaries and coastal waters.

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Natural Resource – “Riparian Areas” 
Riparian areas or zones are also called the floodplain and part of a natural river’s ecosystem. This area is typically defined as wide as the river annually or periodically floods. Normally you would find a diverse selection of trees, shrubs, grasses, cattails and other plant species. Unfortunately, many of these riparian areas have been plowed up to be planted into crops like corn and soybeans or developed for housing and other structures. In addition to helping improve water quality, riparian areas support other benefits ranging from flood protection, providing habitat for wildlife and migrating birds, along with aesthetic values.