The Optical Properties of Greater Florida Bay: Implications for Seagrass Abundance

McPherson, Meredith L.; Hill, Victoria; Zimmerman, Richard C.; Dierssen, Heidi M.

doi:10.1007/s12237-011-9411-9

Cited by 31 publications

(26 citation statements)

References 44 publications

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“…This index was more than double the values for particulate absorption at wavelengths around 400 nm, at both the patch reef and seagrass areas ( Figure 4C,D,E,F). We found relatively high values of total absorption (a p + a g ) (May a tp443q > 0.21 m´1, Oct. a tp443q > 0.14 m´1; Figure 4) compared to previously reported values near the Upper Florida Keys at the Atlantic side in much deeper water (~´17 m) during summer (a tp440q < 0.1 m´1) [32]. In general, the Lower Keys have higher turbidity compared to the Upper Keys [64], although higher productivity has been observed in seagrass and crustose coralline algae communities in the Lower Keys [65,66].…”

Section: Discussionsupporting

confidence: 47%

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

et al. 2016

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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¨O 2¨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¨O 2¨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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Section: Discussionsupporting

confidence: 47%

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

et al. 2016

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“…Typically expressed as light attenuation (or Kd; the vertical attenuation coefficient for downward irradiance), water column clarity is dependent upon f our major water quality agents: 1) re-suspended or terrestrial input of inorganic sediments; 2) chromophoric dissolved organic matter (CDOM); 3) chlorophyll; and 4) other suspended particulate matter (Biber et al, 2005;McPherson et al, 2011). In combination, these constituents influence absorption and scattering of light with depth and the overall light regime available for plants and animals.…”

Section: Introductionmentioning

confidence: 99%

Water clarity patterns in South Florida coastal waters and their linkages to synoptic-scale wind forcing

Pirhalla¹,

Sheridan²,

Lee³

et al. 2017

Satell Oceanogr Meteorol

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Temporal variability in water clarity for South Florida’s marine ecosystems was examined through satellite-derived light attenuation (Kd) coefficients, in the context of wind- and weather patterns. Reduced water clarity along Florida’s coasts is often the result of abrupt wind-resuspension events and other exogenous factors linked to frontal passage, storms, and precipitation. Kd data between 1998 and 2013 were synthesized to form a normalized Kd index (KDI) and subsequently compared with Self Organizing Map (SOM)-based wind field categorizations to reveal spatiotemporal patterns and their inter-relationships. Kd climatological maximums occur from October through December along southern sections of the West Florida Shelf (WFS) and from January through March along the Florida Straits. Spatial clusters of elevated Kd occur along 3 spatial domains: central WFS, southern WFS, and Florida Straits near the Florida Reef Tract, where intra-seasonal variability is the highest, and clarity patterns are associated with transitional wind patterns sequenced with cyclonic circulation. Temporal wind transitions from southerly to northerly, typically accompanying frontal passages, most often result in elevated Kd response. Results demonstrate the potential of using synoptic climatological analysis and satellite indices for tracking variability in water clarity and other indicators related to biological health.

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“…In 1987 approximately 40 km 2 of Thalassia testudinum meadows experienced a major "die-off" in Florida Bay, and that die-off has been followed by smaller (<1 km 2 ) patchy episodes of mortality on an annual basis [1]. Despite tremendous losses suffered in the past 30 years, South Florida still supports roughly 55%-65% of Florida's seagrass resources and the greatest population densities on the state's coastline [33]. The Florida Bay seagrass meadows are intricately linked to the reefs of the Florida Keys, a popular tourist destination with approximately 2.5 million visitors annually generating nearly $1.2 billion for the region [32].…”

Section: Introductionmentioning

confidence: 99%

“…The Florida Bay seagrass meadows are intricately linked to the reefs of the Florida Keys, a popular tourist destination with approximately 2.5 million visitors annually generating nearly $1.2 billion for the region [32]. Although the Florida Bay seagrass landscape is an invaluable cultural and economic resource, a consensus on the primary cause of seagrass losses there has never been ascertained [33]. Therefore, the study area is representative of coastal systems that require better understanding to characterize, monitor and analyze seagrass landscape dynamics to support resource management decisions.…”

Section: Introductionmentioning

confidence: 99%

Supervised Classification of Benthic Reflectance in Shallow Subtropical Waters Using a Generalized Pixel-Based Classifier across a Time Series

2015

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Abstract:We tested a supervised classification approach with Landsat 5 Thematic Mapper (TM) data for time-series mapping of seagrass in a subtropical lagoon. Seagrass meadows are an integral link between marine and inland ecosystems and are at risk from upstream processes such as runoff and erosion. Despite the prevalence of image-specific approaches, the classification accuracies we achieved show that pixel-based spectral classes may be generalized and applied to a time series of images that were not included in the classifier training. We employed in-situ data on seagrass abundance from 2007 to 2011 to train and validate a classification model. We created depth-invariant bands from TM bands 1, 2, and 3 to correct for variations in water column depth prior to building the classification model. In-situ data showed mean total seagrass cover remained relatively stable over the study area and period, with seagrass cover generally denser in the west than the east. Our approach achieved mapping accuracies (67% and 76% for two validation years) comparable with those attained using spectral libraries, but was simpler to implement. We produced a series of annual maps illustrating inter-annual variability in seagrass occurrence. Accuracies may be improved in future work by better addressing the spatial mismatch between pixel size of remotely sensed data and footprint of field data and by employing atmospheric correction techniques that normalize reflectances across images. OPEN ACCESSRemote Sens. 2015, 7 5099

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The Optical Properties of Greater Florida Bay: Implications for Seagrass Abundance

Cited by 31 publications

References 44 publications

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

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

Water clarity patterns in South Florida coastal waters and their linkages to synoptic-scale wind forcing

Supervised Classification of Benthic Reflectance in Shallow Subtropical Waters Using a Generalized Pixel-Based Classifier across a Time Series

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