Image correction for atmospheric effects (iCOR) is an atmospheric correction tool that can process satellite data collected over coastal, inland or transitional waters and land. The tool is adaptable with minimal effort to hyper-or multi-spectral radiometric sensors. By using a single atmospheric correction implementation for land and water, discontinuities in reflectance within one scene are reduced. iCOR derives aerosol optical thickness from the image and allows for adjacency correction, which is SIMilarity Environmental Correction (SIMEC) over water. This paper illustrates the performance of iCOR for Landsat-8 OLI and Sentinel-2 MSI data acquired over water. An intercomparison of water leaving reflectance between iCOR and Aerosol Robotic Network-Ocean Color provided a quantitative assessment of performance and produced coefficient of determination (R 2) higher than 0.88 in all wavebands except the 865 nm band. For inland waters, the SIMEC adjacency correction improved results in the rededge and near-infrared region in relation to optical in situ measurements collected during field campaigns.

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Marine chemical ecology comprises the study of the production and interaction of bioactive molecules affecting organism behavior and function. Here we focus on bioactive compounds and interactions associated with phytoplankton, particularly bloom-forming diatoms, prymnesiophytes and dinoflagellates. Planktonic bioactive metabolites are structurally and functionally diverse and some may have multiple simultaneous functions including roles in chemical defense (antipredator, allelopathic and antibacterial compounds), and/or cell-to-cell signaling (e.g., polyunsaturated aldehydes (PUAs) of diatoms). Among inducible chemical defenses in response to grazing, there is high species-specific variability in the effects on grazers, ranging from severe physical incapacitation and/or death to no apparent physiological response, depending on predator susceptibility and detoxification capability. Most bioactive compounds are present in very low concentrations, in both the producing organism and the surrounding aqueous medium. Furthermore, bioactivity may be subject to synergistic interactions with other natural and anthropogenic environmental toxicants. Most, if not all phycotoxins are classic secondary metabolites, but many other bioactive metabolites are simple molecules derived from primary metabolism (e.g., PUAs in diatoms, dimethylsulfoniopropionate (DMSP) in prymnesiophytes). Producing cells do not seem to suffer physiological impact due to their synthesis. Functional genome sequence data and gene expression analysis will provide insights into regulatory and metabolic pathways in producer organisms, as well as identification of mechanisms of action in target organisms. Understanding chemical ecological responses to environmental triggers and chemically-mediated species interactions will help define crucial chemical and molecular processes that help maintain biodiversity and ecosystem functionality.

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The biogeochemical conditions at the sediment-water interface and along the water column near the discharge of the Santa Marta sewage outfall (SMSO) were studied during the non upwelling (NUPW) and upwelling (UPW) seasons by sedimentary properties and benthic metabolism measurements, as well as, by the implementation of a coupled 3D hydrodynamic-ecological model (AEM3D). Sediment properties (organic matter quantity, C, N and P pools and δ 13 C, δ 15 N and redox potential) and benthic metabolism (aerobic respiration, denitrification, nitrate ammonification and nutrient recycling) were analyzed in four stations located in the proximity and 100, 750 and 1800 m far from the untreated wastewater effluent discharge in both seasons in the Santa Marta Coastal Area (SMCA). From each site, sediment cores were collected between 20 and 30 m depth. Then, the nutrient fluxes were measured in the laboratory via dark incubations; sequentially to fluxes denitrification and dissimilative nitrate reduction to ammonium were measured via the r-IPT (Isotope Pairing Tecnnique). The results indicate that the sediments trace the impact of the outfall (at 750 m and 1800 m with a contribution of terrestrial organic carbon of ~ 40 and ~ 20%, respectively). The results suggest significantly higher sediment oxygen demands (SOD) in the outfall vicinity, as well as a suppression of denitrification and increments in the ammonia nitrogen release through disassimilatory reduction of nitrate to ammonium (DNRA), which was increased during the UPW season.On the other hand, AEM3D model was applied to analyze the seasonal variations of water physicochemical and biological parameters in SMAC under two different nutrient and organic matter loads from wastewater outfall (flow-rate of 1.0 m 3 s -1 and 2.5 m 3 s -1 ) and along the NUPW and UPW season. The model was set up, calibrated and validated based on benthic metabolic measurements carried out within the simulation period, satellite-derived chlorophyll-a (Chl-a) and sea surface temperature (SST) maps, HYCOM database and field and literature water quality data. The model was able to reproduce the magnitude and timing of complex dynamics and fast transitions of temperature, nutrients, and phytoplankton, including the time and duration of stratification and mixing periods during the NUPW and UPW seasons. The model was also able to capture the effect of fertilization from upwelling and from the outfall plume. The wind field was the main driver of nearshore hydrodynamics and the outfall plume dispersion. The shortest average residence times IV of the outfall plume (3.7 ± 0.4 days) corresponded to the period of highest upwelling intensity.Temperature, light intensity and nutrients were the factors that limited phytoplankton growth. The plume concentrations of TOC, TP and PO4 3increased slightly under two scenarios of different wastewater loading. The phytoplankton growth was limited in both NUPW and UPW seasons due to large changes in temperature and advection and mixing in the coastal area, resulting in lar...