Seagrass plays an important role in the marine ecosystem. However, seagrass meadow worldwide are in decline. In Guam, a study has shown that its seagrass meadows have dropped by 22 percent.
When American University Environmental Science Prof. Kiho Kim and his student, Carly K. LaRoche sought to find out the status of seagrass meadows in Guam, they discovered that it had decreased in total size by 22 percent between 2004 and 2015.
Whether the reduction is a long-term trend or whether it is due to natural or human factors has not been determined.
There has not been extensive understanding of seagrass coverage in current literature, particularly in the western tropical Pacific. Nevertheless, the researchers managed to obtain their data using satellite imagery analysis and on-the-ground measurements and mapping of the coastal terrain.
On an international scale, between 1879 and 2006, seagrass meadows have declined by 30 percent. Since 1990, the rate of loss has been accelerating due to coastal development, dredging activities and declining water quality.
According to Kim, Guam’s seagrasses had fared better, despite the loss. This may be due to the level of human activity on the island, which, although increasing, is still significantly lower than in places where large-scale losses have taken place, like the northeast US, the Gulf of Mexico and the Mediterranean.
In any case, the 22 percent decline in Guam’s seagrass meadows adds to other stresses faced by Guam’s coastal areas, where the main pollutant is sewage-derived nitrogen, brought about by poor wastewater infrastructure.