As Wetlands Move Inland Due to Sea Level Rise, Coastal Ecosystems Release More Carbon Into the Atmosphere

According to a new modeling study, coastal ecosystems will not act as a carbon sink but rather will increase atmospheric carbon emissions as swamps move inland as a result of increasing sea levels in six mid-Atlantic states.

Migration in coastal areas

(Photo : ASAAD NIAZI/AFP via Getty Images)

The study raises concerns about whether the carbon benefits of coastal ecosystems will endure in the face of rising sea levels, as per ScienceDaily.

An enlarged location of coastal marshes could potentially acquire more carbon, separating it from the atmosphere in which it behaves as a greenhouse gas in the form of carbon dioxide, according to earlier estimates.

However, as coastal swamps encroach on low-lying forests and wetlands, the death of trees and their subsequent decomposition will discharge too much carbon into the atmosphere than the swamps can hold, further accelerating climate change.

Natural resource organizations in North Carolina, New York, New Jersey, Delaware, Maryland, and Virginia were consulted throughout the study's execution.

To aid in coastal planning, maps of potential changes in coastal areas and carbon rising sea levels were produced.

The study's lead author and a policy associate at Duke's Nicholas Institute for Environmental Policy Solutions, Katie Warnell, said, this study and our discussions with the states start raising various questions about ways of managing coastal landscapes given these changes and stresses the importance of reducing greenhouse and sea-level rise overall because that's the main driver of all of this.

One component of the puzzle is carbon. In addition to providing coastal protection and fisheries with nursery habitats, marshes are important for a variety of other reasons.

When deciding how to manage our coastal habitats, we must consider all of these various aspects. The open-access, peer-reviewed study was released in the PLOS Climate journal on June 23.

In scenarios that forecast intermediate sea level rise, modeling runs examined soil adjustments in coastal regions through the year 2104 Inland marsh migration changed land from being a net carbon sink to being a net carbon source in 16 of the model's 19 runs.

According to Warnell, some measures can be taken to prevent conversion in important areas.

Berms and pumps were used in North Carolina to protect towns and agricultural land from sea level rise, even though they are expensive in some areas.

Ocean's contribution to carbon sinks

The ocean stores carbon in a variety of forms and by far theis major carbon sink and reservoir. Inorganic carbon that has been absorbed is the most prevalent form (DIC). As per Mongabay.

Over millennia, this made its way into the oceans through interactions between seawater and sediments, weathering of the land, anaerobic decomposition from the Earth's interior (for instance, via volcanic vents), and exchanging of gases within the atmosphere. In seawater, the CO2 typically dissolves and exists as carbonate (CO3-), bicarbonate (HCO3-), and CO2 ions.

The ocean's surface, marine organisms, dissolved organic carbon (DOC), and sea surface sediments are the other four oceanic carbon reservoirs. The transitional and deep ocean is thought to be the largest of these reservoirs.

Due to responsible acts of biological carbon pumps, primarily found in the ocean's surface layers, oceans also function as carbon sinks.

Through photosynthesis, phytoplankton converts CO2 from the atmosphere and CO2 that has dissolved in seawater into biomass. Particulate organic carbon (POC), which sinks through the water column, makes up about 25% of this.

Less than 1% of the POC sinking is transported to the ocean floor by sediment deposition and contributes to the ocean floor's carbon sink. The majority of the POC is remineralized by microbes.