Inia Soto

Sea Surface Temperature Variability in the Florida Keys and Its Relationship to Coral Cover

The hypothesis that moderate variability in Sea Surface Temperature (SST) is associated with higher coral cover and slower rates of decline of coral cover within the Florida Keys National Marine Sanctuary (FKNMS) was examined. Synoptic SST time series covering the period 1994–2008 were constructed for the FKNMS with the National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer satellite sensors. The SST data were compared with coral-cover time-series data from 36 sites monitored by the Coral Reef and Evaluation Monitoring Program. Sites that experienced moderately high SST variability relative to other sites showed a trend toward higher percentage coral cover in 2008 and relatively slower rates of decline over the 14-year study period. The results suggest that corals at sites that are continuously exposed to moderate variability in temperature are more resilient than corals typically exposed either to low variability or to extremes.

Shoreline changes in west-central Florida between 1987 and 2008 from Landsat observations

Shoreline changes caused by sediment erosion and accretion have important consequences for coastal ecosystems and coastal communities. Assessing such changes over long stretches of coastline, such as along the west-central Florida coast, represents a challenge to coastal zone managers. In this study, we used nine Landsat Thematic Mapper (TM) images from the west-central Florida coast (adjacent to Tampa Bay, FL) to study historical shoreline changes from 1987 to 2008. Specifically, we sought to evaluate the change of shorelines during the cold (1987–1998) and warm (1998–2008) phases of the Atlantic Multidecadal Oscillation (AMO). The cloud-free images selected for this study were collected during the periods when maximum tidal excursions were less than 9 cm from mean sea level, assuring minimal interference from tidal influence. The images revealed that the southern section of the Tampa Bay inlet showed a mean shoreline accretion rate of 1.30 m year–1 and a cumulative mean shoreline change of 27.29 m over the past 21 years. The northern section of the Tampa Bay inlet showed a mean accretion rate of 0.34 m year–1, with a cumulative mean shoreline change of 7.06 m during the past 21 years. Both sections experienced beach nourishment conducted by local communities which, while irregular, were effective in reducing beach erosion. The dynamics of opposing shores in the various inlets in the barrier islands of the study region varied substantially, with many showing accretion in the channel on one side but erosion on the other side.

Automatic red tide detection from MODIS satellite images

Red tides pose a significant environmental and economic threat in the Gulf of Mexico. Timely detection of red tides is important for understanding this phenomenon. In this paper, learning approaches based on k-nearest neighbors, random forests and support vector machines have been evaluated for red tide detection from MODIS satellite images. Detection results from our algorithms were compared with ground truth red tide data collected in situ. Our results show that red tide identification methods based on machine learning approaches outperform baseline algorithms based on bio-optical characterization.

Characterization of Karenia brevis blooms on the West Florida Shelf using ocean color satellite imagery: implications for bloom maintenance and evolution

Abstract. Satellite ocean color remote sensing techniques, coupled with in situ data, were used to examine the spatial extent and evolution of four Karenia brevis blooms on the West Florida Shelf (WFS) in 2004, 2005, 2006, and 2011. Observations were obtained with the moderate resolution imaging spectroradiometer (MODIS-Aqua). These four blooms were delineated by combining remote-sensing reflectance at 555 nm and normalized fluorescence line height. In 2004 and 2005, the WFS was affected by several hurricanes, including the category 5 storm Hurricane Katrina. These hurricanes led to increased river discharge and vertical mixing which favored bloom intensification and dispersion. No hurricanes passed over the WSF in 2006; however, storms in south Florida may have aided bloom intensification via increased river discharge. In 2011, a bloom appeared off Venice, Florida, where several small creeks discharge. The bloom moved south toward Charlotte Harbor where it intensified and lingered for several months as it received nutrients from riverine discharge and upwelling events. While it is difficult to identify initiation stages of a K. brevis bloom (<∼50,000  cells L−1) using satellite imagery, the techniques used here provide information about bloom evolution (size, duration, and advection) and insight into factors affecting bloom dynamics.

Binational collaboration to study Gulf of Mexico's harmful algae

Blooms of the toxic marine dinoflagellate Karenia brevis cause massive fish kills and other public health and economic problems in coastal waters throughout the Gulf of Mexico [Steidinger, 2009]. These harmful algal blooms (HABs) are a gulf-wide problem that require a synoptic observing system for better serving decision-making needs. The major nutrient sources that initiate and maintain these HABs and the possible connectivity of blooms in different locations are important questions being addressed through new collaborations between Mexican and U.S. researchers and government institutions. These efforts were originally organized under the U.S./Mexico binational partnership for the HABs Observing System (HABSOS), led by the U.S. Environmental Protection Agencys Gulf of Mexico Program (EPAGMP) and several agencies in Veracruz, Mexico, since 2006. In 2010 these efforts were expanded to include other Mexican states and institutions with the integrated assessment and management of the Gulf of Mexico Large Marine Ecosystem (GoMLME) program sponsored by the Global Environment Facility (GEF), the United Nations Industrial Development Organization (UNIDO), the Secretaria de Medio Ambiente y Recursos Naturales (SEMARNAT), and the National Oceanic and Atmospheric Administration (NOAA).