43 research outputs found

    Surface heat exchanges in an estuarine tidal flat (Bahía Blanca estuary, Argentina)

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    The purpose of this article is to provide an analysis of the heat exchanges occurring at a tidal flat of the Bahía Blanca estuary (Argentina). Heat fluxes across the water-atmosphere and sediment-atmosphere interfaces (inundation and exposure, respectively) were studied. Data were collected at Puerto Cuatreros (located near the estuary's head) during one annual cycle (2003). Bulk aerodynamic formulas were used to estimate the radiative and turbulent fluxes from available meteorological data. Air, water and soil temperatures, as well as solar radiation were measured every 10 min. Soil temperature was recorded at three depths (0.05, 0.15 and 0.25 m). Meteorological data were obtained at 30-min intervals from the estuary's weather station located at Puerto Rosales. Atmospheric and tidal conditions regulated the heat exchanges. The most important heat fluxes in every season were net radiation and latent heat flux, reaching maximum values of 816 and 776 W m–2, respectively, after midday in summer. Tidal inundation affected the direction and magnitude of sensible and soil heat fluxes. During a cloudless summer day, nocturnal inundations heated the tidal flat sediment, causing an upward flow of sensible heat. A tidal inundation in the morning cooled the sediment and a downward flow of sensible heat developed (reaching –183 W m–2). Soil heat flux was rapidly reduced during the hours of inundation, becoming nearly zero. The estimated annual evaporation was 2127 mm.

    Beyond just sea‐level rise: considering macroclimatic drivers within coastal wetland vulnerability assessments to climate change

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    Due to their position at the land-sea interface, coastal wetlands are vulnerable to many aspects of climate change. However, climate change vulnerability assessments for coastal wetlands generally focus solely on sea-level rise without considering the effects of other facets of climate change. Across the globe and in all ecosystems, macroclimatic drivers (e.g., temperature and rainfall regimes) greatly influence ecosystem structure and function. Macroclimatic drivers have been the focus of climate change-related threat evaluations for terrestrial ecosystems, but largely ignored for coastal wetlands. In some coastal wetlands, changing macroclimatic conditions are expected to result in foundation plant species replacement, which would affect the supply of certain ecosystem goods and services and could affect ecosystem resilience. As examples, we highlight several ecological transition zones where small changes in macroclimatic conditions would result in comparatively large changes in coastal wetland ecosystem structure and function. Our intent in this communication is not to minimize the importance of sea-level rise. Rather, our overarching aim is to illustrate the need to also consider macroclimatic drivers within vulnerability assessments for coastal wetlands
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