New research reveals that Coastal ecosystems function as a greenhouse gas sink.

New greenhouse gas budget shows that coastal ecosystems globally are net sinks of greenhouse gases carbon dioxide (CO2)₂) but methane emissions (CH₄) and nitrous oxide (N₂o) Face some of the carbon dioxide₂ uptake, according to international researchers led by Australia’s Southern Cross University.

The new findings of the coastal greenhouse gas (CO) balance₂ +CH₄ + n₂O) in 10 global regions and globally in the paper, “Coastal and estuarine vegetation combined is a greenhouse gas sink,” published May 22 in The nature of climate change.

From tropical lagoons to polar fjords, from coastal mangrove forests to underwater seagrass communities, many coasts around the world display a great diversity of greenhouse gas sinks and emissions.

“Understanding how and where greenhouse gases are released and absorbed into coastal ecosystems is an important first step for implementing effective climate change mitigation strategies,” said lead researcher Dr. Judith Rosentreiter, Senior Research Fellow at Southern Cross University.

“For example, protecting and restoring mangrove and salt marsh habitats is a promising carbon dioxide augmentation strategy.₂ It’s absorbed by these coastal wetlands.”

Other activities to reduce human impact, such as reducing nutrients, organic matter, and wastewater inputs into coastal waterways, can reduce the amount of methane.₄ n₂Launch ya into the atmosphere.

The global team of scientists looked at ten different regions of the world: North America, South America, Europe, Africa, Russia, West Asia, South Asia, East Asia, Southeast Asia, and Australia (see Figure 1).

They found that the strongest coastal sink of greenhouse gases (GHG) was in Southeast Asia due to the extensive and productive tropical coastal wetlands that absorb CO2.₂. A second sink hotspot is North America, with its large areas of coastal wetlands but also carbon dioxide₂– Capture fjords.

Our new research shows that fjords around the world take up about 40% of the carbon dioxide₂ that may be released from tidal systems, deltas and lakes. Most (86%) of this important carbon dioxide₂ Co-author Professor Bradley Eyre, Professor of Biochemistry at Southern Cross University, said the uptake of the fjords comes from the North American region, mostly from Greenland.

Dr Rosentreter added, “Other coastal habitats are sources of greenhouse gases. For example, coastal wetlands such as mangrove forests, coastal salt marshes and seagrasses, release more than three times as much methane.₄ of all estuaries in the world.

At the same time, coastal wetlands, also called “blue carbon” coastal wetlands, can be powerful sinks of carbon dioxide.₂ Some also take N₂O, which, in general, makes them a net greenhouse gas sink to the atmosphere when all three greenhouse gases are considered.

In our new study, we showed that when we consider the three greenhouse gases (CO₂ +CH₄ + n₂O), eight out of 10 regions in the world are net coastal sinks of greenhouse gases,” said Dr Rosentreter.

Results will inform efforts RECCAP2 Global Carbon Project.

“The research was initiated by the Global Carbon Project to establish greenhouse gas budgets for large regions covering the entire world, and for which the contribution of these coastal ecosystems has remained missing,” said co-author Pierre Regnier, Professor of Earth System Sciences at the institute. Free University of Brussels.

At a Glance: Coastal sinks and sources of greenhouse gases around the world

A data set of observations from 738 sites was compiled from studies published between 1975 and 2020 to quantify carbon dioxide.₂CH₄n₂O fluxes in estuaries and coastal vegetation in 10 global regions.

The particular coastal features (climate, hydrology, abundance) in each region around the world drive greenhouse gas uptake and/or release from coastal systems.

Strongest coastal greenhouse gas sinks:

• Above: The archipelagic region of Southeast Asia, due to its vast and productive tropical mangrove forests and carbon dioxide-sipping seaweeds.₂.
• Next: North America for its large expanses of salt marshes, mangroves and seagrass but also carbon dioxide₂– Capture fjords.
• Third: Africa with great carbon monoxide₂ Uptake by mangroves and seagrasses moderately reduced by estuarine greenhouse gas emissions.

Temperate coastal greenhouse gas sinks:

• South America: moderate CO₂ Uptaken by coastal wetlands, especially mangroves, and some greenhouse gas emissions at estuaries.
• Australia: Long stretches of coastal wetlands that take up carbon dioxide₂but this region also has a large number of estuaries along its coasts, many of which are sources of carbon dioxide₂CH₄ n₂s.
• West Asia: Weak estuarine greenhouse gases and moderate CO2₂ It is absorbed by coastal wetlands, mostly seaweeds.

Weak coastal sinks of greenhouse gases:

• East Asia and South Asia: temperate coastal wetlands CO₂ Sink largely of estuarine greenhouse gas emissions.

Sources of weak coastal greenhouse gases:

• Europe and Russia: Both regions release more coastal greenhouse gases than they can absorb from the atmosphere. These regions have many affected tidal estuaries that release greenhouse gases; The cooler climate also means they have fewer coastal wetlands (for example, mangrove forests) that would otherwise take up large amounts of carbon dioxide.₂.