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The Marano-Grado Lagoon (MGL) is extensively contaminated by mercury (Hg) from local sources and long-term (500 years) tidally delivered inputs from the Idrija Hg mine (Slovenia) through Isonzo River suspended loads. A multibox WASP-7 (Water Analysis Simulation Program) model was used to simulate the long-term dynamics of the mercury cycle in the MGL. Scenario simulations were used to compute changes in the system over 100 years. Present and future Hg concentrations in water, sediment, and Hg budgets were compared, including evasion and MeHg inputs to the Mediterranean Sea, based on climate changes and mercury capping in tributary rivers. Using the Ref baseline scenario, the model computes a general decrease in Hg T of 13% in the water column and of 80% in sediment and a strong MeHg increase in sediment (+73%). The net sea export of Hg T decreases by 57% to up to 48 kg/y while MeHg increases by 10% to up to 0.63 kg/y. The lagoon sediment recovery time of Hg T up to a target level of 0.3 mg/kg is computed over 570 years for surface sediments (1750 for subsurface sediments). When removing Hg from boundaries, the same target value for surface sediments is reached within 110 years. [ABSTRACT FROM AUTHOR]

The majority of Scotland's saline lagoons are located on the low-lying coastlines of the Western Isles and the northern archipelagos of Orkney and Shetland, where recorded annual relative sea level rise rates are among the highest in Scotland. The sediment-impounded lagoons of Orkney and Shetland will either lose their impoundment and become incorporated in marine coastal waters, or become increasingly saline, as relative sea levels rise. The rock-basin lagoons of the Western Isles will retain their restricted exchange with the sea but will also become more saline with rising sea level. Specialist lagoonal organisms tend to have wide salinity tolerances but may succumb to competition from marine counterparts. In all areas, there are sufficient fresh-water inland water bodies with potential to be captured as lagoons to compensate for loss of extent and number, but the specialist lagoon biota tend to have limited dispersal powers. It is thus possible that they will be unable to transfer to their analogue sites before existing lagoons become fully marine, giving conservation managers the problem of deciding on management options: leave natural processes to operate without interference, manage the saline inflow to maintain the current salinity regime, or translocate lagoon organisms perceived as threatened by rising salinities. Timing of conversion and capture is unpredictable due to local topography and complications caused by variable stratification. [ABSTRACT FROM AUTHOR]

In the scope of the first WDF management cycle, a multi-municipality sanitation system with secondary treatment was implemented in 2005 in Ria de Aveiro coastal lagoon, with the treated effluent discharging into the Atlantic Ocean through a submarine outfall. The lagoon water chemical status was evaluated regarding dissolved inorganic nutrients and chlorophyll a before and after 2005. The S. Jacinto outfall has effectively reduced the point source nutrient loads (ammonium and phosphate) into Ria de Aveiro, representing a step forward for the implementation of the WFD, through eutrophication abatement. However, the lagoon remains exposed to non-point nitrogen sources, as a consequence of the current land use and water management, which in a scenario of winter extreme precipitation events, nutrients increase through surface run-off. Besides, in a combined scenario of low freshwater input into the lagoon and favourable oceanic condition, nutrients enter through Ria outer boundary coming from the S. Jacinto outfall. Thus, changes in the system hydrodynamics in the context of global change might pose new challenges regarding the WFD second management cycle involving the second river basin management plan and the first flood risk management plan, foreseeing the ‘Good’ ecological status in all Ria's Water Bodies. [ABSTRACT FROM AUTHOR]

Lagoons are highly productive coastal features that provide a range of natural services that society values. Their setting within the coastal landscape leaves them especially vulnerable to profound physical, ecological, and associated societal disturbance from global climate change. Expected shifts in physical and ecological characteristics range from changes in flushing regime, freshwater inputs, and water chemistry to complete inundation and loss and the concomitant loss of natural and human communities. Therefore, managing coastal lagoons in the context of global climate change is critical. Although management approaches will vary depending on local conditions and cultural norms, all management scenarios will need to be nimble and to make full use of the spectrum of values through which society views these unique ecosystems. We propose that this spectrum includes pragmatic, scholarly, aesthetic, and tacit categories of value. Pragmatic values such as fishery or tourism revenue are most easily quantified and are therefore more likely to be considered in management strategies. In contrast, tacit values such as a sense of place are more difficult to quantify and therefore more likely to be left out of explicit management justifications. However, tacit values are the most influential to stakeholder involvement because they both derive from and shape individual experiences and beliefs. Tacit values underpin all categories of social values that we describe and can be expected to have a strong influence over human behavior. The articulation and inclusion of the full spectrum of values, especially tacit values, will facilitate and support nimble adaptive management of coastal lagoon ecosystems in the context of global climate change. [ABSTRACT FROM AUTHOR]