Upwelling of phosphorus-rich deep water promotes an N-fixing symbiont of the Sargassum algae giving it a competitive advantage.
Upwelling of phosphorus-rich deep water promotes an N-fixing symbiont of the Sargassum algae giving it a competitive advantage.
By the beginning of June this year, approximately 38 million tons of Sargassum drifted towards the coasts of the Caribbean islands, the Gulf of Mexico, and northern South America, marking a negative record. Especially during the summer months, the brown algae accumulate on beaches, decomposing and emitting a foul odor. This not only repels tourists but also threatens coastal ecosystems. In the open ocean, Sargassum seaweed floating on the surface serves as nourishment and habitat for numerous marine species.
The algae originally come from the Sargasso Sea, located east of Florida. However, since 2011, researchers have repeatedly observed the so-called Great Atlantic Sargassum Belt, a gigantic carpet of gulfweed that drifts from the equator towards the Caribbean when easterly winds prevail. Until now, the sources of nutrients phosphorus (P) and nitrogen (N) fueling their rapid growth was unclear. It was hypothesized that nutrient runoff from overfertilization and rainforest deforestation might be responsible. However, these processes cannot explain the increase in Sargassum biomass observed during the past years.
Read More: Max Planck Institute for Chemistry
Photo Credit: hat3m via Pixabay
