The Importance of Biodiversity: The Gulf of Mexico’s Hypoxic Zone

Hypoxia is the depletion of dissolved oxygen to such an extent that water can no longer support its living organisms.

Biodiversity is the variety of species, genes, and natural communities on earth and is central to healthy ecosystems. An ecosystem shelters a diverse amount of species, purifies water, absorbs pollution, produces healthier soil, and provides nutrients to plants, animals, and humans. Decreasing the level of biodiversity through pollution and environmental change can result in species extinction and degradation when organisms cannot adapt quickly enough to the changes. One example of the devastating effects of decreased biodiversity is the United States’ Gulf of Mexico’s hypoxia zone.

The Gulf of Mexico  is currently home to the largest-occurring hypoxia zone in the United States and the second largest in the world, roughly the size of Massachusetts. Hypoxia occurs naturally, and the Gulf Coast’s hypoxia blooms every spring and ends in the summer. The unfortunate news is that the Gulf Coast’s hypoxia zone is widely understood to be a result from the massive runoff of nitrogen into the Mississippi River. Nitrogen (approximately 1.5 million tons annually) is largely used by farmers to fertilize their crops but also serves as food for phytoplankton. The nitrogen-rich waters escalate the phytoplankton’s population growth to unnaturally high levels. When phytoplankton die, their bodies decompose and bacteria feed upon them, further depleting oxygen levels in the water.

While some organisms can evacuate the hypoxia zone before being harmed, others cannot. Slow-moving organisms like shellfish die because they are stressed or cannot escape to oxygen-abundant waters fast enough. The result is a dead-zone. The Gulf Coast’s hypoxia or dead-zone disrupts the fragile web of life that so many organisms and animals rely upon.  The ever-increasing use of nitrogen-based fertilizers means that the hypoxic region may grow, and the amount of oxygen in the water may shrink, eventually affecting shrimp, crab, and various fish’ populations.

There is some optimism in the air. In 2009, the United States Department of Agriculture announced an initiative (Mississippi River Basin Healthy Watersheds Initiative or MRBI) to disperse $320 million within four years to improve the Mississippi River basin’s health/ Specifically, funds went to farmers to help them implement better techniques to reduce or avoid fertilizer run-off. In its “2013 Progress Report”, the MRBI achieved its financial goal, surpassing the amount of funding by $7 million for conservation projects. You can help as well by engaging in water conservation and monitoring programs in your state. To find out the programs in your state, please visit the EPA’s watershed database.