Biogeochemical flows are the pathways by which elements like carbon, phosphorus, nitrogen, and sulfur, or compounds like water, flow between living organisms and the environment. Human activities can alter these cycles in a variety of ways as we interact with ecosystems and natural resources.  

For example, agricultural fertilizer and soil erosion have substantially increased levels of biologically available nitrogen and phosphorus in natural systems. The synthetic production of nitrogen entering ecosystems through fertilizers is now greater than all forms of natural production combined, and phosphorus levels in bodies of water due to the runoff from agricultural and mining activities are dangerously high, though under-reported. 

The overabundance of nitrogen decreases plant diversity in terrestrial ecosystems, and the combination of excess nitrogen and phosphorus in water bodies leads to algal blooms, eutrophication, and biodiversity loss, as well as shifts in disease vectors, such as malaria. Resulting soil pollution decreases the nutritional quality of crops and contributes to nutritional disease in humans. Water quality is particularly vulnerable to rapid changes in runoff and temperature fluctuation as climate change destabilizes seasonal weather patterns. Fluctuating water quality affects the availability of drinkable water, and the marine ecosystems humans rely on for food and livelihoods.

“…an unchecked and unbalanced addition [of fertilizers] can have grave and possibly not easily reversible consequences for marine ecosystems, e.g., mass mortality of benthic communities and increased microbial growth.”

– Schobben et al., Eutrophication, microbial-sulfate reduction and mass extinctions.