Biofuels destroys the Gulf of Mexico
The decision of the USA to make in the future the basic rate on biological fuel means for the Gulf inevitable expansion of its oxygen-poor dead zone. This conclusion comes microbiologists from Carnegie Mellon University in Pittsburgh. According to their findings, published in the journal «Environmental Science and Technology», even the use of cellulose as a feedstock for bioethanol production will not stop the process of reducing the oxygen content in the Gulf, despite the fact that nitrogen fertilizer at the same time requires much less than with biofuels from cornstarch.
Lowering the oxygen content created in recent decades, large areas of the Gulf of Mexico a vast dead zone, which for most higher organisms - fish, crabs, shrimp - leaves no chance of survival. The greatest size of the zone reaches the spring and summer, when the Mississippi and the second distributary of its delta - Atchafalaya River - bring in the bay water with high concentration of nutrients. These nutrients, mainly nitrogen and phosphorus, are a part used in the midwestern U.S. chemical fertilizers, which are a result of the rains washed down from the soil surface and penetrated into the groundwater. In rivers they fall into the bay and promote intensive growth of algae, which are decomposed by means of bacteria, absorbing oxygen from the water in large quantities.
Several U.S. states have already launched programs to reduce nutrient discharges into the bay, which is likely to lead to a threefold reduction in the dead zone - from 15000 to 5000 square kilometers. However, in 2007 the U.S. Senate dealt a fatal blow to these plans, deciding on the production of 136 billion liters of ethanol annually until 2022. But biofuels produced, including, as a result of intensive use of fertilizers, particularly if the biofuel is used as the basis for corn starch. According to the plans of Americans, the number of corn-based ethanol is expected to reach 40 percent of the total production of biofuels, that is tripled. Other types of energy products should be manufactured from cellulose or other crops, cultivation of which less expensive in terms of energy and mineral fertilizers.
Recent studies show that the number falling from the mouths of rivers into the ocean nitrogen, promotes the widening of the algae will grow and the use of cellulose. Even if it will bring a 20-percent decrease compared to the mixture used today, switching to less demanding in terms of all types of fertilizers will not yield tangible results.
It shall come into force and other factors conducive to the growth of oxygen-poor areas, says Andreas Oshlis from the Institute of Marine Research, named after the Leibniz (Leibnitz-Institut für Meereswissenschaften) (IFM-GEOMAR)
Plays a role in this case, and carbon. The increase of CO2 in the atmosphere stimulates the growth of carbon sequestration in algae on the surface of the sea. Like people, excessively consume junk food, the algae on a carbon diet "get fat", and as a result of bacteria in the decomposition of phytoplankton consume more oxygen. Therefore, the dead zone will grow with the increase of CO2 in the atmosphere, even if the intensity of use of mineral fertilizers will remain at the same level "
A separate problem is the production of raw materials for biofuels, according to Oshlis, it is often of low economic efficiency of fertilizers, as well as their uncontrolled use. "Based on the profitability of farms, raw materials for biofuels are cultivated today in the scale monoculture, which requires an increasing amount of mineral fertilizers. Manufacture of food products has long been built on the principle of economical fertilizer, which is not observed in the case of biofuels, say experts of biogeochemical modeling.