Title: PHYSICAL PROCESSES CONTROLLING CONNECTIVITY AMONG SOUTH FLORIDA CORAL REEFS AND PATHWAYS OF UPSTREAM RIVER INFLUENCE

Abstract: A combination of in situ and satellite measurements and high resolution modeling are combined to study the connectivity among South Florida coral reef systems and the influence of upstream nutrient sources on local water properties. The study area covers the mesophotic Pulley Ridge reef on the Southwest Florida Shelf and the Florida Keys shallow reef system, extending to the Dry Tortugas. An unprecedented 3-year time series of currents and temperature reveals dominant circulation modes and pathways that are influenced by both shelf dynamics and the proximity of the large scale Loop Current (LC) - Florida Current (FC) system. Modulations of the LC/FC system, changes in LC core (from extended to retracted position in the Gulf of Mexico) and eddy passages were key factors in the connectivity pathways. Moreover, two major episodes of Mississippi water offshore removal took place during the study period, with in situ data quantifying their low-salinity signal around Pulley Ridge and the Florida Keys. Such episodes directly influence water quality around coral reefs in the Northern Gulf of Mexico, but also have remote impacts. For the first time, thick lenses of low salinity and high in nutrient content waters of Mississippi River origin were traced hundreds of kilometers away from the Mississippi Delta to the South Florida reefs, under both flooding and below normal Mississippi discharge conditions. A targeted numerical study elucidated the related processes and revealed complex pathways connecting remote reef systems in the Gulf of Mexico.

Authors: Kourafalou VH, Smith RH, Valle-Levinson A, Le Hénaff M, Kang H, Androulidakis Y

Presentation: Oral

Session: 15

Date: 06/23/16

Time: 14:00

Location: 317 A/B

Back