A Novel Metric to Evaluate the Association Rules for Identification of Functional Dependencies in Complex Technical Infrastructures

Environment Systems and Decisions - Functional dependencies in complex technical infrastructures can cause unexpected cascades of failures, with major consequences on availability. For this reason,...     

Experimental investigation of the near-surface flow dynamics in downburst-like impinging jets

Environmental Fluid Mechanics - Downbursts are strong downdrafts that originate from thunderstorm clouds and create vigorous radial outflows upon hitting the ground. This study is part of the...     

The role of wetlands in the chromophoric dissolved organic matter release and its relation to aquatic ecosystems optical properties. A case of study: Katonga and Bunjako Bays (Victoria Lake; Uganda)

Chromophoric Dissolved Organic Matter (CDOM) is an important component in freshwater and marine ecosystems and plays direct and indirect role in biogeochemical cycles. CDOM originates from the degradation process of organic materials, usually macrophytes and planktons. The present work examines the importance of wetland derived CDOM on the optical and bio-optical properties of two bays of Lake Victoria (Uganda, Africa). This was achieved by determining the attenuation and extinction coefficients of filtered and unfiltered water samples from two equatorial bays on the Ugandan coastline of Lake Victoria. Katonga Bay is a wetland lined bay that receives water from the Katonga river, while Bunjako Bay is an outer bay between Katonga Bay and Lake Victoria. The results showed that attenuation was highest in Katonga Bay and the role of CDOM is most dominant near the river inlet. The quantity and quality of CDOM is extremely different in the two bays: in Katonga Bay it is possible to hypothesize a terrestrial origin of CDOM (transported by the wetland river). On the contrary, in Bunjako Bay, spectral measurements of absorption indicate a modified CDOM and/or alternative CDOM source. The terrestrial CDOM in Katonga Bay is more capable of absorbing harmful UV radiation than the CDOM present in the Bunjako Bay. The resulting optical environment in the former bay presented a water column with a very limited penetration of harmful UV radiation, while a higher penetration was observed in the Bunjako Bay.     

Integrated biomonitoring assessment of the Lesina Lagoon (Southern Adriatic Coast, Italy): preliminary results

An integrated biomonitoring program for marine and coastal ecosystems quality assessment combines the chemical characterization of a site with the evaluation of the possible structure alterations of its living communities. This can be considered an useful tool for better identifying the summarized effects of all the components interacting with the biota. Such an integrated procedure was carried out for the assessment of the quality of the Lesina Lagoon (Southern Adriatic Coast, Italy). The water parameters levels showed a high primary production (2-6 μg l^-1); the sediment and pore water toxicity bioassays recorded a low or moderate diffused toxicity. Besides, the benthic meiofauna community structure was characterized by prevalent Nematoda taxa with a homogeneous spatial distribution. On these basis, the Lesina Lagoon seems to be characterized by a prevalent organic pollution mainly related to agricultural and zootechnical activities which, due to the lagoon's conformation, presents a homogeneous spatial distribution.     

Ecosystem services as a counterpart of emergy flows to ecosystems

A generic input-state-output scheme has been used to represent ecosystem dynamics. Systemic approaches to ecosystems use functions that are based either on inputs, state or outputs of the system. Some examples of approaches that use a combination of functions have been recently proposed. For example the use of eco-exergy to emergy flow can be seen as a mixed input-state approach; more recently, to connect the state to the output of the ecosystem, the relation of eco-exergy and ecosystems services has been proposed. This paper studies the link between the useful output of an ecosystems and its input through the relation between ecosystem services and emergy flow, in a kind of grey/black box scheme (i.e., without considering the state and the structure of the ecosystem). No direct connection between the two concepts can be determined, but identifying and quantifying the emergy flows feeding an ecosystem and the services to humans coming from them facilitate the sustainable conservation of Nature and its functions. Furthermore, this input-output relation can be established in general by calculating the ratio of the value of the ecosystem services to the emergy flow that supports the system. In particular, the ratio of the world ecosystem services to the emergy flow supporting the entire biosphere has been calculated showing that, at least at the global level, Nature is more efficacious in producing “money” (in form of ecosystem services) than economic systems (e.g., national economies and their GDP).     

The key role played by the Augusta basin (southern Italy) in the mercury contamination of the Mediterranean Sea

The Augusta basin, located in SE Sicily (southern Italy), is a semi-enclosed marine area, labelled as a highly contaminated site. The release of mercury into the harbour seawater and its dispersion to the blue water, make the Augusta basin a potential source of anthropogenic pollution for the Mediterranean Sea. A mass balance was implemented to calculate the HgT budget in the Augusta basin. Results suggest that an average of ～0.073 kmol of HgT is released, by diffusion, on a yearly basis, from sediments to the seawater, with a consequent output of 0.162 kmol y(-1) to coastal and offshore waters; this makes the Augusta area an important contributor of mercury to the Mediterranean Sea. Owing to the geographical location of the Augusta basin, its outflowing shelf-waters are immediately intercepted by the surface Atlantic Ionian Stream (AIS) and mixed with the main gyres of the eastern Mediterranean Sea, thus representing a risk for the large-scale marine system.     

A functional perspective on the analysis of land use and land cover data in ecology

Assessments of large-scale changes in habitat are a priority for management and conservation. Traditional approaches use land use and land cover data (LULC) that focus mostly on “structural” properties of landscapes, rather than “functional” properties related to specific ecological processes. Here, we contend that designing functional analyses of LULC can provide important and complementary information to traditional, structural analyses. We substantiate this perspective with an example of functional changes in habitat due to industrial anthropogenic footprints in Alberta’s boreal forest, where there has been little overall forest loss (~ 6% structural change), but high levels of functional change (up to 93% functional change) for species’ habitat, biodiversity, and wildfire ignition. We discuss the methods needed to achieve functional LULC analyses, when they are most appropriate to add to structural assessments, and conclude by providing recommendations for analyses of LULC in a future of increasingly high-resolution, dynamic remote sensing data.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01434-5) contains supplementary material, which is available to authorized users.