Ana Bio

Heterogeneity of soil surface ammonium concentration and other characteristics, related to plant specific variability in a Mediterranean-type ecosystem

Heterogeneity and dynamics of eight soil surface characteristics essential for plants--ammonium and nitrate concentrations, water content, temperature, pH, organic matter, nitrification and ammonification rates--were studied in a Mediterranean-type ecosystem on four occasions over a year. Soil properties varied seasonally and were influenced by plant species. Nitrate and ammonium were present in the soil at similar concentrations throughout the year. The positive correlation between them at the time of greatest plant development indicates that ammonium is a readily available nitrogen source in Mediterranean-type ecosystems. The results presented here suggest that plant cover significantly affects soil surface characteristics.

Artisanal salt production in Aveiro/Portugal - an ecofriendly process.

Solar salinas are man-made systems exploited for the extraction of salt, by solar and wind evaporation of seawater. Salt production achieved by traditional methods is associated with landscapes and environmental and patrimonial values generated throughout history. Since the mid-twentieth century, this activity has been facing a marked decline in Portugal, with most salinas either abandoned or subjected to destruction, making it necessary to find a strategy to reverse this trend.It is, however, possible to generate revenue from salinas at several levels, not merely in terms of good quality salt production, but also by obtaining other products that can be commercialized, or by exploring their potential for tourism, and as research facilities, among others. Furthermore, with an adequate management, biodiversity can be restored to abandoned salinas, which constitute important feeding and breeding grounds for resident and migratory aquatic birds, many of which are protected by European Community Directives.The aims of this manuscript are to present a brief overview on the current state of sea salt exploitation in Portugal and to stress the importance of recovering these salinas for the conservation of this particular environment, for the regional economy, the scientific community and the general public. The Aveiro salina complex is presented in detail, to exemplify salina structure and functioning, as well as current problems and potential solutions for artisanal salinas.

Surviving an Invasion: Characterization of One of the Last Refugia for Artemia Diploid Parthenogenetic Strains

The eradication of native populations of Artemia by the invasive A. franciscana constitutes one of the most conspicuous examples of biodiversity loss in hypersaline aquatic environments. Detailed information on the biological mechanisms that are supporting the invasion process, as well as on the importance of environment variables, is of paramount importance if adequate measures aiming at preventing the eradication of native strains are to be successfully implemented. Although the role of environmental stress in benefiting invasions has recently been documented, there seems to be little information on the characterization of environments where invasion is delayed or has failed altogether. Given that both the biotic and abiotic parameters of salt ponds within the Aveiro’s salinas complex (Portugal) presently occupied by A. franciscana have already been thoroughly characterised (Vieira and Bio, Journal of Sea Research 65:293–303, 2011), we will compare the same variables to those measured in an artisanal salina from the same complex, where native Artemia still occurs. Since there is no indication of salt ponds where both the native and invasive species co-occur, we hypothesise that explicit differences in environmental factors (e.g. salinity, temperature, pH, alkalinity, dissolved oxygen availability or nutrient concentrations) would help justify the observed distribution pattern of both Artemia species.

The Importance of Marine Observatories and of RAIA in Particular

Coastal and Oceanic Observatories are important tools to provide information on ocean state, phenomena and processes. They meet the need for a better understanding of coastal and ocean dynamics, revealing regional characteristics and vulnerabilities. These observatories are extremely useful to guide human actions in response to natural events and potential climate change impacts, anticipating the occurrence of extreme weather and oceanic events and helping to minimize consequent personal and material damages and costs. International organizations and local governments have shown an increasing interest in operational oceanography and coastal, marine and oceanic observations, which resulted in substantial investments in these areas. A variety of physical, chemical and biological data have been collected to better understand the specific characteristics of each ocean area and its importance in the global context. Also the general public’s interest in marine issues and observatories has been raised, mainly in relation to vulnerability, sustainability and climate change issues. Data and products obtained by an observatory are hence useful to a broad range of stakeholders, from national and local authorities to the population in general. An introduction to Ocean Observatories, including their national and regional importance, and a brief analysis of the societal interest in these observatories and related issues are presented. The potential of a Coastal and Ocean Observatory is then demonstrated using the RAIA observatory as example. This modern and comprehensive observatory is dedicated to improve operational oceanography, technology and marine science for the North Western Iberian coast, and to provide services to a large range of stakeholders.

Three-dimensional data collection for coastal management – efficiency and applicability of terrestrial and airborne methods

ABSTRACT Regular monitoring is essential to understand coastal morphodynamics and anthropic as well as natural impacts, at different temporal and spatial scales. A stereoscopic video-based terrestrial mobile mapping system, three airborne digital photography systems (mounted on a small manned airplane, a fixed-wing UAV and a multi-rotor UAV, respectively) and airborne LiDAR were compared in terms of: system features, such as range, autonomy, acquisition and operating costs; information supplied, its type and precision; and constraints to system applicability in coastal topographic surveys. Systems differed in resolution, efficiency, and applicability. The terrestrial and UAV-based systems provided the most accurate 3D data, being particularly suited for small-scale, high-resolution surveys. UAVs were easy to deploy, but limited by weather condition, particularly wind speed. Observations from a plane were most efficient and suited for larger areas. Airborne systems had the advantage of being less (UAV) to non-invasive (plane) and thus suitable for the monitoring of sensitive areas (e.g. dunes) and/or areas with difficult access. Systems should be chosen according to the specific survey aims, spatial scale, and local conditions, taking into account their applicability and cost-benefit ratios. They may complement each other to provide a comprehensive picture of coastal morphology and dynamics at different scales.

Biomanipulation of Furnas Lake, Azores: effects of repeated fish removal

Fumas Lake is a small mesoto eutrophic water body located in an ancient volcanic crater ofSiio Miguellsland Azores. In addition to agricultura( nutrient inputs, high densities of herbivorous fish (mainly common carp), as well as (irregular) hypolimnetic aeration contribute to maintain high levels of turbidity in the lake through resuspension of the nutrients accumulated in the sediment. ScHEFFER et al. ( 1993) suggested that turbidity in shallow lakes is not a smooth function of their nutrient status. Lakes are thought to have 2 distinct equilibria: a clear state dominated by macrophytes anda turbid state dominated by algae. A shift from turbid to clear water conditions is favoured by ( 1) reduction ofnutrient concentrations, reducing algal growth; (2) increased light availability, favouring vegetation, which retains sediments, protects zooplankton and consumes nutrients; and (3) reduction of planktivorous and benthos-feeding fish stock, reducing consumption of zooplankton, which grazes on phytoplankton, and reducing sediment resuspension with release of nutrients from the sediment pool (JEPPESEN et al. 2007). To improve water quality in the Fumas lake, a substantial part of the herbivorous and bottomfeeding (thus sediment resuspending) fish population, mainly common carp, was removed. Water quality was analysed in terms of turbidity, chlorophyll a, trophic state index values, macrophytes and zooplankton.