Contributions of organic alkalinity (Org-Alk) to total alkalinity (TA) were investigated in surface waters from three different coastal environments (estuary, urban, mangrove) and offshore sites in the Gulf of Mexico. ∆TA was calculated as the difference between directly measured TA, and TA calculated from total dissolved inorganic carbon (DIC) and pH. In low nutrient surface waters, ∆TA should be dominated by Org-Alk with minor contributions from inorganic nutrients (e.g., HPO 4 2and SiO(OH) 3-). Average values of ∆TA were 0.1 ± 5.0 µmol kg-1 at coastal sites outside the Mississippi-Atchafalaya River Estuary (n = 17), 33.6 ± 18.0 µmol kg-1 in the Suwannee River Estuary (n = 17), 16.0 ± 25.4 µmol kg-1 in the Tampa Bay, Caloosahatchee River, and Ten Thousand Islands area (n = 55), and-1.0 ± 4.9 µmol kg-1 in offshore waters (n = 14) in the northern Gulf of Mexico. In addition to Org-Alk assessments based on ∆TA, procedures were developed for direct spectrophotometric measurements of Org-Alk via titrations of samples that were purged of CO 2. Two-step titrations of these DIC-free samples consisted of a first titration from pH 4.5 to 6.0 performed using bromocresol purple (BCP), and a second titration, from pH 6.0 to about 8, using cresol red (CR) as the indicator. By diluting all samples, including the offshore reference sample, to a common salinity (the lowest salinity of the coastal samples), borate alkalinity was presumed to be identical for all samples. Org-Alk values were calculated as differences between titration results obtained for coastal samples and the offshore reference sample and, through ancillary nutrient measurements, accounted for alkalinity contributions from silicate and phosphate. The direct titrations confirmed the existence of substantial Org-Alk in coastal samples. Spectrophotometric titration data were also used for model fitting in order to assess the dissociation constants (pK i) of the organic acids. The pK i of the organic acids were within the previously reported range for riverine fulvic acids.

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Building on the spectrophotometric procedure of Yao and Byrne (1998), an automated analysis system has been developed for laboratory and shipboard measurements of total alkalinity at a rate of 6 samples per hour. The system is based on single-point hydrochloric acid (HCl) titrations of seawater samples of a known volume with bromocresol purple as an indicator. The titration is continuously monitored using visible spectroscopy to guide the titration rate according to the real-time pH of the samples. Each titration is terminated just below the equivalence point to achieve a precision and accuracy near 1 mol kg-1 .

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The goals of this project were to determine the daily, seasonal and spatial patterns of red grouper Epinephelus morio sound production on the West Florida Shelf (WFS) using passive acoustics. An 11 month time series of acoustic data from fixed recorders deployed at a known E. morio aggregation site showed that E. morio produce sounds throughout the day and during all months of the year. Increased calling (number of files containing E. morio sound) was correlated to sunrise and sunset, and peaked in late summer (July and August) and early winter (November and December). Due to the ubiquitous production of sound, large-scale spatial mapping across the WFS of E. morio sound production was feasible using recordings from shorter duration-fixed location recorders and autonomous underwater vehicles (AUVs). Epinephelus morio were primarily recorded in waters 15-93 m deep, with increased sound production detected in hard bottom areas and within the Steamboat Lumps Marine Protected Area (Steamboat Lumps). AUV tracks through Steamboat Lumps, an offshore marine reserve where E. morio hole excavations have been previously mapped, showed that hydrophone-integrated AUVs could accurately map the location of soniferous fish over spatial scales of <1 km. The results show that passive acoustics is an effective, non-invasive tool to map the distribution of this species over large spatial scales.

-The Center for Robot-Assisted Search and Rescue (CRASAR R ) deployed the custom Sea-RAI man-portable unmanned surface vehicle and two commercially available underwater vehicles (the autonomous YSI EcoMapper and the tethered VideoRay) for inspection of the Rollover Pass bridge in the Bolivar peninsula of Texas in the aftermath of Hurricane Ike. A preliminary domain analysis with the vehicles identified two key tasks in subsurface bridge inspection (mapping of the debris field and inspecting the bridge footings for scour), three research challenges (navigation under loss of GPS, underwater obstacle avoidance, and stable positioning in high currents without GPS), and possible improvements to humanrobot interaction (having additional display units so that mission specialists can view and operate on imagery independently of the operator control unit, incorporating 2-way audio to allow operator and field personnel to communicate while launching or recovering the vehicle, and the inclusion of teleoperation as the backup mode for autonomy). An additional research question is the cooperative use of surface and underwater vehicles.

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While it is widely known that numerous fish species produce sound, discerning when and where is more challenging. Through the use of autonomous passive acoustic technology, the spatial and temporal patterns of fish sound production, namely red grouper Epinephelus morio, in the eastern Gulf of Mexico were documented. Two methods have been employed off west-central Florida: moored passive acoustic arrays deployed in 2008 and 2009 covering over 16 600 km2 from the coast to 100 m deep, and autonomous gliders with integrated hydrophones deployed cross-shelf for up to 4weeks. Over four million acoustic files generated from these methods were analyzed using DSGLab, an open-source database and data analysis system implemented using Matlab and MySQL. An automatic detection algorithm was created and implemented in DSGLab to determine the presence of red grouper calls. False detections were removed manually and the results were analyzed to determine diel and seasonal variability of red grouper sound production in addition to identifying the range of red grouper in the eastern Gulf of Mexico. Support was provided by the University of South Florida, Center for Ocean Technology glider staff, and the captains and crew of the R/Vs Weatherbird II, FishHawk, Eugenie Clark, and Allicat, and the M/V Narcosis. This research was funded by NOPP (OCE-0741705) awarded to DM and the USF/USGS Graduate Assistantship awarded to CW.