It has long been recognized that sharks help nourish coral reefs, but just how – or to what extent – has never really been charted. Until now.
However, a study of gray reef sharks ( Carcharhinus amblyrhynchos ), a predatory species commonly associated with coral environments whose long-standing environmental role has long been debated, shows that the predators use their fecal matter They transfer vital nutrients from their open feeding grounds to shallower reef environments, contributing to the overall health of these fragile ecosystems.
"The role of sharks as top predators is well understood, but their role as nutrient vectors is much less explored."
"Our study shows that large mobile predators such as sharks are an important nutrient source even for the smallest reef inhabitants such as corals co-author Jennifer Caselle, biologist at the University of California at Santa Barbara's Marine Research Institute. "The role of sharks as top predators is well understood, but their role as nutrient vectors is much less studied."
Working in the waters around Palmyra Atoll-a national nature reserve 1
The researchers then analyzed this tracking data as a spatial motion network and were able to do this for the first time, estimating the amount of nitrogen deposited around the distant, unfinished reef of the Palmyra Atoll via the shark's feces material.
The results estimate that this specific population of gray reef sharks – which is believed to number about 8,300 individuals – adds up to 94.5 kg (208.3 pounds) of nitrogen per day for the reef ecosystem, an amount that is likely to be significant contributes to the primary productivity of the reef.
By searching for prey in deep pelagic waters, often miles away, sharks function as vital "nutrient vectors" for shallow reefs. They bring along valuable nutrient sources, such as nitrogen, which in turn effectively serve as fertilizer for thousands of other species that call these reef environments home.
Sensor mimics the & # 39; sixth sense & # 39; Shark's Organ According to
The results have implications for the scientific understanding of fragile coral reef ecosystems and the ecological importance of gray reef sharks, scientists say. The species is currently classified as "near threatened" by the International Union for the Conservation of Nature.
"Combined with their more prominent role as predators, our study underscores another, less obvious, role of reef sharks in enhancing the resilience of these fragile habitats and underscoring the vital importance of conserving these and other common predators," says senior co-author David Jacoby from the Zoological Institute of the Zoological Society in London.
Darcy Bradley of UCSB is co-author of the paper that appears in Procedures of the Royal Society B . Other contributions are from Imperial College London and Florida International University.
Source: UC Santa Barbara