Characterization of Available Light for Seagrass and Patch Reef Productivity in Sugarloaf Key, Lower Florida Keys

Authors

Gerardo Toro-Farmer, University of South FloridaFollow
Frank E. Muller-Karger, University of South FloridaFollow
Maria Vega-Rodriguez, University of South Florida
Nelson Melo, Florida International University
Kimberly Yates, U.S. Geological Survey
Sergio Cerdeira-Estrada, National Commission for Knowledge and Use of Biodiversity (CONABIO)
Stanley R. Herwitz, NASA Research Park

Document Type

Article

Publication Date

1-23-2016

Keywords

Florida Keys, corals, seagrass, light spectrum, benthos productivity

Digital Object Identifier (DOI)

https://doi.org/10.3390/rs8020086

Abstract

Light availability is an important factor driving primary productivity in benthic ecosystems, but in situ and remote sensing measurements of light quality are limited for coral reefs and seagrass beds. We evaluated the productivity responses of a patch reef and a seagrass site in the Lower Florida Keys to ambient light availability and spectral quality. In situ optical properties were characterized utilizing moored and water column bio-optical and hydrographic measurements. Net ecosystem productivity (NEP) was also estimated for these study sites using benthic productivity chambers. Our results show higher spectral light attenuation and absorption, and lower irradiance during low tide in the patch reef, tracking the influx of materials from shallower coastal areas. In contrast, the intrusion of clearer surface Atlantic Ocean water caused lower values of spectral attenuation and absorption, and higher irradiance in the patch reef during high tide. Storms during the studied period, with winds >10 m·s⁻¹, caused higher spectral attenuation values. A spatial gradient of NEP was observed, from high productivity in the shallow seagrass area, to lower productivity in deeper patch reefs. The highest daytime NEP was observed in the seagrass, with values of almost 0.4 g·O₂·m⁻²·h⁻¹. Productivity at the patch reef area was lower in May than during October 2012 (mean = 0.137 and 0.177 g·O₂·m⁻²·h⁻¹, respectively). Higher photosynthetic active radiation (PAR) levels measured above water and lower light attenuation in the red region of the visible spectrum (~666 to ~699 nm) had a positive correlation with NEP. Our results indicate that changes in light availability and quality by suspended or resuspended particles limit benthic productivity in the Florida Keys.

Rights Information

This work is licensed under a Creative Commons Attribution 4.0 License.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Remote Sensing, v. 8, issue 2, art. 86

Scholar Commons Citation

Toro-Farmer, Gerardo; Muller-Karger, Frank E.; Vega-Rodriguez, Maria; Melo, Nelson; Yates, Kimberly; Cerdeira-Estrada, Sergio; and Herwitz, Stanley R., "Characterization of Available Light for Seagrass and Patch Reef Productivity in Sugarloaf Key, Lower Florida Keys" (2016). Marine Science Faculty Publications. 253.
https://digitalcommons.usf.edu/msc_facpub/253