Thomas Robinson | May 25th, 2020
Coastal marshes in the Gulf of Mexico have been shown to have tipping points in a new study. Tipping points, are when coastal marshes are unable to keep up with the rate of sea-level rise and become submerged over time destroying the marsh ecosystem.
Sediment cores were used from the Mississippi Delta to investigate how coastal marshes reacted to changes in their environment over the past 8,500 years. Researchers found that even a small increase in the rate of sea level rise would result in large areas of coastal marshland becoming submerged. Researchers found that rates above 3 millimeters per year is the likely threshold for coastal marshes to survive. Unfortunately, current rates of sea-level rise are beyond that threshold suggesting that the remaining marshes in the Delta will likely drown within the century.
Coastal wetlands, such as marshes, are one of the most valuable ecosystems in the world. They are extremely productive regions that have significant environmental and economic benefits. They provide homes for diverse ecosystems that can benefit species diversity which results in robust fisheries. Coastal wetlands also provide flood protection and erosion control for coastal areas which help to reduce the effect storms have on the coastline.
As coastal wetlands in the Mississippi River Basin are stressed from sea-level rise, they are also inundated with sediment and nutrients flowing from upstream. Iowa is a major contributor to this issue and even though efforts are underway to alleviate the stress, coastal wetlands will be negatively affected by the state’s agriculture for years to come.