Werner Francisco E.

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Werner
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Francisco E.
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Models : tools for synthesis in international oceanographic research programs

2010-09 , McGillicuddy, Dennis J. , deYoung, Brad , Doney, Scott C. , Glibert, Patricia M. , Stammer, Detlef , Werner, Francisco E.

Through its promotion of coordinated international research programs, the Intergovernmental Oceanographic Commission (IOC) has facilitated major progress on some of the most challenging problems in oceanography. Issues of global significance—such as general ocean circulation, the carbon cycle, the structure and dynamics of ecosystems, and harmful algal blooms—are so large in scope that they require international collaboration to be addressed systematically. International collaborations are even more important when these issues are affected by anthropogenic processes— such as climate change, CO2 enhancement, ocean acidification, pollution, and eutrophication—whose impacts may differ greatly throughout the global ocean. These problems require an entire portfolio of research activities, including global surveys, regional process studies, time-series observations, laboratorybased investigations, and satellite remote sensing. Synthesis of this vast array of results presents its own set of challenges (Hofmann et al., 2010), and models offer an explicit framework for integration of the knowledge gained as well as detailed investigation of the underlying dynamics. Models help us to understand what happened in the past, and to make predictions of future changes—both of which support the development of sound policy and decision making. We review examples of how models have been used for this suite of purposes, focusing on areas where IOC played a key role in organizing and coordinating the research activities.

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Cold event in the South Atlantic Bight during summer of 2003 : model simulations and implications

2007-05-11 , Aretxabaleta, Alfredo L. , Blanton, Brian O. , Seim, Harvey E. , Werner, Francisco E. , Nelson, James R. , Chassignet, Eric P.

A set of model simulations are used to determine the principal forcing mechanisms that resulted in anomalously cold water in the South Atlantic Bight (SAB) in the summer of 2003. Updated mass field and elevation boundary conditions from basin-scale Hybrid Coordinate Ocean Model (HYCOM) simulations are compared to climatological forcing to provide offshore and upstream influences in a one-way nesting sense. Model skill is evaluated by comparing model results with observations of velocity, water level, and surface and bottom temperature. Inclusion of realistic atmospheric forcing, river discharge, and improved model dynamics produced good skill on the inner shelf and midshelf. The intrusion of cold water onto the shelf occurred predominantly along the shelf-break associated with onshore flow in the southern part of the domain north of Cape Canaveral (29° to 31.5°). The atmospheric forcing (anomalously strong and persistent upwelling-favorable winds) was the principal mechanism driving the cold event. Elevated river discharge increased the level of stratification across the inner shelf and midshelf and contributed to additional input of cold water into the shelf. The resulting pool of anomalously cold water constituted more than 50% of the water on the shelf in late July and early August. The excess nutrient flux onto the shelf associated with the upwelling was approximated using published nitrate-temperature proxies, suggesting increased primary production during the summer over most of the SAB shelf.

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Techniques for cetacean–habitat modeling

2006-04-03 , Redfern, J. V. , Ferguson, M. C. , Becker, E. A. , Hyrenbach, K. D. , Good, Caroline P. , Barlow, Jay , Kaschner, K. , Baumgartner, Mark F. , Forney, K. A. , Ballance, L. T. , Fauchald, P. , Halpin, Patrick N. , Hamazaki, T. , Pershing, Andrew J. , Qian, Song S. , Read, Andrew J. , Reilly, S. B. , Torres, Leigh , Werner, Francisco E.

Cetacean–habitat modeling, although still in the early stages of development, represents a potentially powerful tool for predicting cetacean distributions and understanding the ecological processes determining these distributions. Marine ecosystems vary temporally on diel to decadal scales and spatially on scales from several meters to 1000s of kilometers. Many cetacean species are wide-ranging and respond to this variability by changes in distribution patterns. Cetacean–habitat models have already been used to incorporate this variability into management applications, including improvement of abundance estimates, development of marine protected areas, and understanding cetacean–fisheries interactions. We present a review of the development of cetacean–habitat models, organized according to the primary steps involved in the modeling process. Topics covered include purposes for which cetacean–habitat models are developed, scale issues in marine ecosystems, cetacean and habitat data collection, descriptive and statistical modeling techniques, model selection, and model evaluation. To date, descriptive statistical techniques have been used to explore cetacean–habitat relationships for selected species in specific areas; the numbers of species and geographic areas examined using computationally intensive statistic modeling techniques are considerably less, and the development of models to test specific hypotheses about the ecological processes determining cetacean distributions has just begun. Future directions in cetacean–habitat modeling span a wide range of possibilities, from development of basic modeling techniques to addressing important ecological questions.

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Population connectivity in marine systems : an overview

2007-09 , Cowen, Robert K. , Gawarkiewicz, Glen G. , Pineda, Jesus , Thorrold, Simon R. , Werner, Francisco E.

There is growing consensus that life within the world’s ocean is under considerable and increasing stress from human activities (Hutchings, 2000; Jackson et al., 2001). This unprecedented strain on both the structure and function of marine ecosystems has led to calls for new management approaches to counter anthropogenic impacts in the coastal ocean (Botsford et al., 1997; Browman and Stergiou, 2004: Pikitch et al., 2004). Spatial management, including Marine Protected Areas (MPAs), has been touted as a method for both conserving biodiversity and managing fisheries (Agardy, 1997). Continuing debates on the efficacy of MPAs have identified the need for models that capture the spatial dynamics of marine populations, especially with respect to larval dispersal (Willis et al., 2003; Sale et al., 2005). Theoretical studies suggest that population connectivity plays a fundamental role in local and metapopulation dynamics, community dynamics and structure, genetic diversity, and the resiliency of populations to human exploitation (Hastings and Harrison, 1994; Botsford et al., 2001). Modeling efforts have been hindered, however, by the paucity of empirical estimates of, and knowledge of the processes controlling, population connectivity in ocean ecosystems. While progress has been made with older life stages, the larval-dispersal component of connectivity remains unresolved for most marine populations. This lack of knowledge represents a fundamental obstacle to obtaining a comprehensive understanding of the population dynamics of marine organisms. Furthermore, a lack of spatial context that such information would provide has limited the ability of ecologists to evaluate the design and potential benefits of novel conservation and resource-management strategies.

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