Exactly nine years ago, on April 20, 2010, one of the largest environmental disasters in history occurred in the Gulf of Mexico - an oil spill as a result of an accident on the Deepwater Horizon oil platform. Pollution still affects coastal salt marshes, and plants play a key role in the restoration of these important ecosystems, according to a long-term study.
“Our study highlights the important role that plants play in restoring the coastal ecosystem of the Gulf of Mexico,” said expert David Johnson of the Marine Science Institute of the College of William and Mary in Virginia.
Healthy salt bogs are dominated by two plants - Spartina alterniflora and Juncus roemerianus. There are also many unicellular organisms on the surface, which scientists call benthic microalgae, and small invertebrates - nematodes, snails, worms and others - swim and crawl in the root zone.
Scientists have measured the abundance and biomass of these organisms in heavily polluted, moderately polluted and clean areas of Barataria Bay in Louisiana. Sampling was carried out at six-month intervals between 2011 and 2016. Early sampling showed that almost all plants in heavily contaminated areas died, and benthic microalgae and invertebrates were significantly reduced. A later sample showed that the recovery of the marshes was due to benthic microalgae and spartina, which began to show significant growth within two to three years.
Only after the growth of Spartina began a noticeable restoration of the invertebrate community. This is because marsh grasses facilitate colonization for soil organisms, nourish the food web, provide habitat for animals, release oxygen, bind soil, and slow down water flow.
The results indicate that oil spill mitigation strategies should include planting key species such as Spartina.
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