Unmanned Aerial Vehicle Collaborative

ABSTRACTAn atmospheric correction algorithm has been developed for the Airborne Imaging Spectrometer for Applications (AISA) imagery over optically shallow waters in Sugarloaf Key of the Florida Keys. The AISA data were collected repeatedly during several days in May 2012, October 2012, and May 2013. Non-zero near-infrared (NIR) remote-sensing reflectance (Rrs) was accounted for through iterations, based on the relationship of field-measured Rrs between the NIR and red wavelengths. Validation showed mean ratios of 0.94–1.002 between AISA-retrieved and in situ Rrs in the blue to red wavelengths, with uncertainties generally <0.003 sr–1. Such an approach led to observations of short-term changes in AISA-retrieved Rrs from repeated measurements over waters with bottom types of seagrass meadow, sand, and patch reef. Some of these changes are larger than twofold the Rrs uncertainties from AISA retrievals, therefore representing statistically significant changes that can be well observed from airborne measurements. Through radiative transfer modelling, we demonstrated that short-term Rrs changes within 1 hour resulted primarily from sediment resuspension, while tides played a relatively minor role due to the small variation in tidal heights. A sensitivity analysis indicated that although Rrs generally increases with decreasing tide height but increasing suspended sediments, more changes were observed over sandy bottom than over seagrass. The case study suggests that repeated airborne measurements may be used to study short-term changes in shallow-water environments, and such a capacity may be enhanced with future geostationary satellite missions specifically designed to observe coastal ecosystems.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 538:35-52 (2015) - DOI: https://doi.org/10.3354/meps11385 Community metabolism in shallow coral reef and seagrass ecosystems, lower Florida Keys D. Turk1,2,*, K. K. Yates3, M. Vega-Rodriguez4, G. Toro-Farmer4, C. L’Esperance1, N. Melo5,6, D. Ramsewak7, M. Dowd1, S. Cerdeira Estrada8, F. E. Muller-Karger4, S. R. Herwitz9, W. R. McGillis2 1Dalhousie University, Halifax, NS B3H 4R2, Canada 2LDEO, Columbia University, New York, NY 10964, USA 3U.S. Geological Survey, St. Petersburg, FL 33701, USA 4College of Marine Science, University of South Florida, St. Petersburg, FL 33701, USA 5Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL 33149, USA 6NOAA Atlantic Oceanographic and Meteorological Laboratory, 4301 Rickenbacker Causeway, Miami 33149, USA 7Marine Sciences, The University of Trinidad and Tobago, TT, Trinidad and Tobago 8National Commission for Knowledge and Use of Biodiversity (CONABIO), Mexico City, 14010, Mexico 9UAV Collaborative, Moffett Field, CA 94035, USA *Corresponding author: daniela.turk@dal.ca ABSTRACT: Diurnal variation of net community production (NEP) and net community calcification (NEC) were measured in coral reef and seagrass biomes during October 2012 in the lower Florida Keys using a mesocosm enclosure and the oxygen gradient flux technique. Seagrass and coral reef sites showed diurnal variations of NEP and NEC, with positive values at near-seafloor light levels >100–300 µEinstein m-2 s-1. During daylight hours, we detected an average NEP of 12.3 and 8.6 mmol O2 m-2 h-1 at the seagrass and coral reef site, respectively. At night, NEP at the seagrass site was relatively constant, while on the coral reef, net respiration was highest immediately after dusk and decreased during the rest of the night. At the seagrass site, NEC values ranged from 0.20 g CaCO3 m-2 h-1 during daylight to -0.15 g CaCO3 m-2 h-1 at night, and from 0.17 to -0.10 g CaCO3 m-2 h-1 at the coral reef site. There were no significant differences in pH and aragonite saturation states (Ωar) between the seagrass and coral reef sites. Decrease in light levels during thunderstorms significantly decreased NEP, transforming the system from net autotrophic to net heterotrophic. KEY WORDS: Coral reef · Seagrass · Production · Calcification · Florida Keys Full text in pdf format Supplementary material PreviousNextCite this article as: Turk D, Yates KK, Vega-Rodriguez M, Toro-Farmer G and others (2015) Community metabolism in shallow coral reef and seagrass ecosystems, lower Florida Keys. Mar Ecol Prog Ser 538:35-52. https://doi.org/10.3354/meps11385 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 538. Online publication date: October 28, 2015 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2015 Inter-Research.