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Abstract--The variability in the supply of pink shrimp (Farfantepenaeus duorarum) postlarvae and the transport mechanisms of planktonic stages were investigated with field data and simulations of transport. Postlarvae entering the [...]

Abstract Coupled physical-biological models are capable of linking the complex interactions between environmental factors and physical hydrodynamics to simulate the growth, toxicity and transport of infectious pathogens and harmful algal blooms (HABs). Such simulations can be used to assess and predict the impact of pathogens and HABs on human health. Given the widespread and increasing reliance of coastal communities on aquatic systems for drinking water, seafood and recreation, such predictions are critical for making informed resource management decisions. Here we identify three challenges to making this connection between pathogens/HABs and human health: predicting concentrations and toxicity; identifying the spatial and temporal scales of population and ecosystem interactions; and applying the understanding of population dynamics of pathogens/HABs to management strategies. We elaborate on the need to meet each of these challenges, describe how modeling approaches can be used and discuss strategies for moving forward in addressing these challenges.

The presence of all three classes of pathogens (viral, protozoan and bacterial) as well as indicator microbes at a non-point source recreational beach is assessed. The analysis of the various microbes under different targeted environmental conditions has included the evaluation of the sources of microbial contaminants and pathogens and the effectiveness of various analytical methods for microbe detection.

Biscayne Bay, a marine lagoon along the southeast Florida coast, has been affected by altered freshwater input due to water management construction features and operations. The Comprehensive Everglades Restoration Plan aims to improve the quantity, quality, timing, and distribution of freshwater flow through central Florida to the southern coasts and to restore nearshore estuarine conditions in Biscayne Bay. The Biscayne Bay Simulation Model (BBSM) is used to evaluate the effects of proposed changes to freshwater flow on salinity in the bay. However, a recent version of the model has left out the groundwater component due to uncertainty in its quantity, a critical shortcoming considering the porous substrate connecting the bay to inland freshwater sources and historic evidence of fresh groundwater discharge. As a result, the BBSM had been unable to reproduce mean salinity and salinity variability along the shoreline. In the present effort, salinity data from an expanded set of monitoring stations were used to estimate the quantity of the fresh groundwater discharge component. Adjustments in friction in the shallow nearshore regions were also made to increase salinity variability to mimic natural conditions. The result, referred to as BBSM version 4, has improved salinity behavior in the critical nearshore region while maintaining previous salinity performance mid-bay. A substantial coastal freshwater component was required to simulate nearshore salinity during portions of the year. This is an interesting finding that suggests groundwater and other freshwater sources along the coast, including convection driven precipitation events, may have been underestimated and require further investigation. [ABSTRACT FROM AUTHOR]

Human health protection at recreational beaches requires accurate and timely information on microbiological conditions to issue advisories. The objective of this study was to develop a new numerical mass balance model for enterococci levels on nonpoint source beaches. The significant advantage of this model is its easy implementation, and it provides a detailed description of the cross-shore distribution of enterococci that is useful for beach management purposes. The performance of the balance model was evaluated by comparing predicted exceedances of a beach advisory threshold value to field data, and to a traditional regression model. Both the balance model and regression equation predicted approximately 70% the advisories correctly at the knee depth and over 90% at the waist depth. The balance model has the advantage over the regression equation in its ability to simulate spatiotemporal variations of microbial levels, and it is recommended for making more informed management decisions. [ABSTRACT FROM AUTHOR]

Reports on the development of a numerical model to describe the currents, residence times, salinity patterns and larval transport in a South Biscayne Bay, Florida lagoonal system. Inclusion of tides, wind and freshwater inflows in model forcing; Agreement of computed tidal currents with observations; Average difference of computed salinity.

Coupled physical-biological models are capable of linking the complex interactions between environmental factors and physical hydrodynamics to simulate the growth, toxicity and transport of infectious pathogens and harmful algal blooms (HABs). Such simulations can be used to assess and predict the impact of pathogens and HABs on human health. Given the widespread and increasing reliance of coastal communities on aquatic systems for drinking water, seafood and recreation, such predictions are critical for making informed resource management decisions. Here we identify three challenges to making this connection between pathogens/HABs and human health: predicting concentrations and toxicity; identifying the spatial and temporal scales of population and ecosystem interactions; and applying the understanding of population dynamics of pathogens/HABs to management strategies. We elaborate on the need to meet each of these challenges, describe how modeling approaches can be used and discuss strategies for moving forward in addressing these challenges.