Part 2: From land to sea, though not forgetting freshwater, river and streams

Key terms here: fertilisers, eutrophication or hypertrophication, hypoxia, deadzones.

Although fertilisers have revolutionized agriculture since the 19^th century, its use for animal agriculture and growing feed has major implication on our environment, today.  Fertilisers, both chemical or natural, are rich in nutrient, and particularly high in nitrogen and phosporus, that help increase crop yields. However, plants only intake less than 20% of nitrogen and phosphorus (Dybas 2005), the rest is washed away by rain and ends up directly in freshwater and groundwater ecosystems, riparian environments and oceans (See table). Nutrient encourage the growth of aquatic plants such as phytoplankton, just as they do on land. The lake is thus exposed to a process of eutrophication (excessive numbers of nutrient in an aquatic environment) and causes oxygen depletion a.k.a. hypoxia in which aquatic organisms are unable to survive due to the low oxygen concentrations. The remaining bodies of water are called dead zone.

Cattle manure is rich in nitrogen, phosphorus and potassium, which represent the major causes of eutrophication. One peer-reviewed study argued that Industrialised Animal Production were major sources of nutrients and therefore were contributing to the eutrophication of some environments in the United States (Mallin et al, 2003). Focusing on Concentrated Animal Feeding Operations (CAFOs), which represent big companies for intensive meat production, Mallin et al (2013) argue that the high concentration of CAFOs puts pressure on regional environment due to major imbalance in waste production and the capacity to effectively manage this waste. This ‘mismanaged’ waste is left to spread on fields and enters our environment through a process groundwater infiltration and overland flow (Edwards et al, 1992). In consequence, some of North Carolina’s major lakes have experienced large microbial contaminations and the presence of algal bloom that have caused major fish kills. These surface runoff not only affect large lakes and rivers but also heavily impact smaller temporal water bodies such as vernal pools, that are particularly important for containing endemic plant species but are often used for cattle grazing due it promoting the growth of native plant species (Brudvig et al, 2007). A recent 2011 study (Croel et al, 2011) showed that, though cattle grazing nearby vernal pools might increase some plant diversity on land, cattle manure was influencing vernal pool water quality. The presence of nutrient rich materials in pools, have caused increasing growth of algal blooms which have been detrimental for the already endangered plant communities that live amongst vernal environments (Croel et al, 2011).

 This post explained and presented how the livestock industries are indirectly affecting freshwater environments such as wetlands, lakes , rivers and streams