Nutrient Pollution Affecting Salt Marshes’ Ability to Sequester Carbon

Back in August, when irrepressible fires caused by slash-and-burn deforestation raged through South America’s rainforests, scientists worried that the burning trees would release CO2 back into the atmosphere. Rainforests are carbon sinks, natural environments that sequester and store CO2 from the atmosphere. When trees are burned, however, the stored CO2 is released back into the atmosphere.

Now, scientists worry that another one of Earth’s carbon sinks is releasing CO2: salt marshes.

Salt Marshes as Carbon Sinks

Salt marshes—grasslands that are flooded by sea water—sequester and store CO2 from the atmosphere in two ways. Vegetation absorbs CO2 via photosynthesis and then stores it as organic carbon in plant tissues. Carbon is also stored in sediments, organic matter, and peat deposits within the marsh.

According to Project Drawdown, an organization dedicated to finding solutions to global warming, protecting coastal wetlands would keep 53 gigatons of CO2 from entering the atmosphere.

Yet, new studies have found that salt marshes’ ability to store CO2 is decreasing due to nitrate pollution from fertilizer runoff.

Nutrient Pollution Negatively Affects Salt Marshes

Researchers from Massachusetts conducted an experiment, published as “Nitrate Addition Stimulates Microbial Decomposition of Organic Matter in Salt Marsh Sediments” in Global Change Biology, in which three samples of salt marsh sediments were collected in Plum Island Sound, MA and tested to determine how large amounts of nitrate affect microbes.

Under normal circumstances, the microbes in salt marshes remove nitrogen from the soil through a process known as denitrification and release it into the atmosphere as nitrous oxide. Due to the microbes’ function, scientists have long held the belief that salt marshes were resilient to nitrogen pollution.

This study, however, reveals that large amounts of nitrate from fertilizer runoff are shifting the composition of the microbial community. The excess nitrate is stimulating the production of dissolved inorganic carbon, resulting in the decomposition of organic matter usually left undisturbed in these marshes. The microbes are now degrading organic matter at an alarming rate, reducing the marshes’ ability to store carbon.

While slash-and-burn deforestation in South America seems inexorable—as many farmers refuse to convert to modern and sustainable agricultural practices—the pollution of salt marshes can be stopped. To reduce the amount of CO2 entering the atmosphere and warming the planet, fertilizer runoff must be reduced.

Reducing Nutrient Pollution

Currently, researchers are investigating ways to reduce fertilizer runoff. In Rice County, Minnesota, a team led by Dr. Paul Jackson, Associate Professor of Chemistry and Environmental Studies at St. Olaf College, is researching the ways in which cover crops reduce fertilizer runoff.

According to Dr. Jackson, the results of his study suggest that “fields planted with cover crops discharge a lower concentration of nitrate compared to fields without cover crops.”

In Portsmouth, England, the City Council has voted to introduce oyster beds in the strait of Solent, where nitrate pollution has accelerated the growth of algae. Oysters sequester and store nitrogen in their tissues and cells. Additionally, they create a microbiome of bacteria that performs denitrification.

Introducing something to the environment that can reduce nitrate pollution is one option, but mitigating nutrient pollution at its source is ideally the best decision. This begins with investigating our fertilizers.

Using Environmentally Friendly Fertilizer

Conventional, solid fertilizers are difficult for plants to absorb, as these solids can accumulate into nitrogen hotspots. Then, when it rains, these solids are washed into rivers and streams, polluting the water. Furthermore, because plants only absorb 50 percent of nitrogen introduced into the soil, farmers often use excess fertilizer, which further contributes to nutrient pollution.

xVital, xVirity’s revolutionary fertilizer, is liquid in form, so it doesn’t clump together and wash away into our water resources. Furthermore, because it is mixed with water, plants have an easier time absorbing it, so nitrogen isn’t lost and excess fertilizer isn’t necessary.

There are various ways we can prevent the destruction of the earth’s natural carbon sinks and the exacerbation of climate change. Invest in a fertilizer that doesn’t contribute to nutrient pollution and protect the earth’s resources by checking out xVital today.

For further reading on nutrient pollution, check out these articles:

Algae Blooms on the Rise: Scientists Point to Biosolids as Possible Culprit 

Factory Farm Waste is Destroying our Environment 

Climate Change is Not the Only Culprit for Dying Coral in Florida

Extreme Algae Bloom in Lake Pontchartrain and the Coast of Mississippi

Minnesota Fertilizer Rule set for Approval 

Naples Florida Bans Lawn Fertilizer During Rainy Season 



Synthetic Fertilizers Disrupt Carbon-Catching Ability of Salt Marshes

Oysters Considered to Cut Solent Nitrate Pollution

See How Cover Crops Can Clean Up Streams

How Oysters may Help Reduce Nitrogen Pollution