• Photosynthesis is an essential process that occurs within an ecosystem. Fueled by energy from the sun, plants convert water and carbon dioxide in the atmosphere into carbohydrates. Plants can adapt to temporary shortages in these elements. However, chemicals can negatively affect photosynthesis by disrupting gas exchange or causing damage to plants. A plant negatively impacted by pollutants will not undergo photosynthesis but rather will focus its resources on recovery from the environmental impacts. New growth stops.
  
  

Sulfur Dioxide

• Sulfur dioxide from coal-plant emissions causes physical damage to plants through acid rain. Acid rain occurs when this chemical combines with moisture in the atmosphere to create acidic precipitation. Acid rain impairs photosynthesis by damaging leaves, the primary site where the process occurs. It also triggers other reactions that mobilize aluminum in the soil. Aluminum naturally occurs in a non-toxic form. When it is mobilized, it reduces populations of soil micro-organisms. The availability of nutrients decreases, resulting in a slowing of photosynthesis as plants attempt to conserve resources.
  
  

Arsenic

• Arsenic is a heavy metal often found in acidic mine drainage. Toxic runoff containing arsenic negatively impacts photosynthesis by lowering chlorophyll concentrations in plants as reported in a 2007 study published in the journal, Chemosphere. Chlorophyll is vital for photosynthesis to occur as this molecule captures energy from the sun to fuel the process.
  
  

Glyphosate

• Glyphosate is a chemical commonly found in garden pesticides such as Roundup and Rodeo. It enters the environment through drift by spraying the herbicide during windy conditions, runoff and accidental spills. Glyphosate interferes with photosynthesis by reducing chlorophyll and causing physical damage to plant leaves. Glyphosate is especially toxic in that it is a nonselective pesticide. A nonselective pesticide can potentially harm non-targeted plant species.
  
  

Phosphorus

• Phosphorus is chemical found in fertilizers. Phosphorus poses its greatest threat to aquatic plants. Phosphorus entering aquatic environments causes a surge in plant growth referred to as an algae bloom. As the algae die, bacteria begin the decomposition process. Soon, levels of dissolved oxygen decrease. Ammonia in the water increases. Photosynthesis ceases as conditions become acidic and too toxic to support life.
  
  

Nitrogen

• Nitrogen-containing fertilizers enter the environment primarily through agricultural runoff. While it can benefit plant growth, it can also have negative effects on plants. Nitrogen causes an increase in the above-ground portion of the plant. A nutrient imbalance results when the root system cannot keep up with the needs of the plant. Plants become vulnerable to disease, parasites and winter damage. Photosynthesis slows as the plant attempts to cope with the increased impact of environmental stress.