Characterization of available light for seagrass and patch reef productivity in Sugarloaf Key, Lower Florida Keys

Remote Sensing
By: , and 

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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.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Characterization of available light for seagrass and patch reef productivity in Sugarloaf Key, Lower Florida Keys
Series title Remote Sensing
DOI 10.3390/rs8020086
Volume 8
Issue 2
Year Published 2016
Language English
Contributing office(s) St. Petersburg Coastal and Marine Science Center
Description 20 p.
First page 1
Last page 20
Country United States
State Florida
Other Geospatial Lower Florida Keys, Sugarloaf Key
Online Only (Y/N) N
Additional Online Files (Y/N) N