Eutrophication, the over-enrichment of freshwater and coastal ecosystems with nutrients, is being recognized as a rapidly growing environmental crisis. Eutrophication occurs when nutrients, particularly nitrogen (N) and phosphorus (P), from water runoff or atmospheric deposition stimulate the growth of algae and cause cascading environmental effects.

Research is showing that offshore ocean waters, traditionally perceived to be nutrient sparse particularly in oligotrophic environments like the Caribbean, is rapidly changing. The deposition of organic chemical and nutrient-loading pollution into the marine environment globally increased 65% between 2003–2013, contributing to eutrophication choking oxygen from oceans creatures. Worldwide, approximately $164 billion is spent annually on water and wastewater treatments and despite these massive investments in nutrient management, coastal waters across the globe continue to experience significant and growing nutrient loading

Enhanced nutrient levels are stimulating the growth and subsequent decay of micro and macroalgae, contributing to severe ecosystem impacts, such as noxious and harmful algal blooms, reduced water quality, and low dissolved oxygen conditions causing massive “dead zones” where overgrowths consume so much oxygen that nothing else can survive. Consider that the Gulf of Mexico dead zone caused by nutrient pollution grew to 6,634 square miles in the summer of 2021.

Environmental credit trading programs have gained traction for pollutants like atmospheric carbon emissions but there has been minimal media buzz about ocean nutrient pollutants. Could this be the next frontier for a nutrient pollutant credit trading market promoting ocean acidification as the evil twin for climate change?

Nutrient trading markets would allow operators producing point sources of water pollution to offset that pollution by purchasing credits representing reductions elsewhere. Just as the purchase of a carbon offset gives its buyer credit for reducing their carbon footprint, such a trading market would allow a participant to buy and sell the credit for reduction of nutrient pollution.

Seaplants are marine “ﬁxators” for bio-remediating eutrophic waters having the potential to help mitigate this least recognized, and increasingly most urgent, ecological crisis destabilizing the Earth's natural nitrogen and phosphorus cycle. Seaplants could significantly reduce excess nitrogen flowing into coastal waters, while also replacing synthetic fertilizers to reduce the amount of nitrogen entering the ocean from agricultural sources. The nutrient extraction capacity of seaplants grown in Xincun Bay, China was reported by scientists to remove 53.8 metric tons of nitrogen and 3.7 metric tons of phosphorus during the 1999-2000 growing season.

Market opportunities will soon emerge for seaplant mariculture, as a nature-based solution, to become a cost effective and revenue generating intervention for remediating ocean nutrient pollution.