New primary production in northwest European shelf seas, 1960–2003

Spatial and temporal patterns from 1960 to 2003 in annual potential new primary production (PNP) of the NW European shelf seas were derived from general additive models of nitrate concentrations and from data on riverine and atmospheric fluxes of oxidized nitrogen. Average PNP was highest in the seasonally stratified outer shelf regions (>70 gC m-2 yr-1), where the proportion of PNP accounted for by vertical fluxes from deep water (>65%) was correlated with the North Atlantic Oscillation (NAO) index. PNP was lowest in the central North Sea (~30 gC m-2 yr-1) and in the southern North Sea was correlated with river inputs that accounted for 24% of the annual total (average ~50 gC m-2 yr-1). Atmospheric deposition accounted for ~3% of annual PNP region-wide, but in the northern North Sea this was higher than the contribution from rivers. Tidal fronts are traditionally considered to be highly productive zones, but we find them to have characteristically low PNP and conclude that they must be loci of high recycled production. The results indicate an exceptional flux of nitrate-rich ocean water onto the shelf in the early 1990s, which resulted in a pulse of PNP coincident with a well-documented 'regime shift' in the pelagic food web. North Sea-wide, long-term average PNP was approximately equal to production by all higher trophic levels combined, though trophic propagation of inter-annual variations was weakly defined. Nevertheless, there is a case for proposing that harvesting in areas and periods of low PNP should be managed more conservatively to minimize the risk of detrimental effects on the food web

From cylindrical to non‐cylindrical foreland basin: Pliocene–Pleistocene evolution of the Po Plain–Northern Adriatic basin (Italy)

n/

Habitat continuity and stepping-stone oceanographic distances explain population genetic connectivity of the brown alga Cystoseira amentacea

Effective predictive and management approaches for species occurring in a metapopulation structure require good understanding of interpopulation connectivity. In this study, we ask whether population genetic structure of marine species with fragmented distributions can be predicted by stepping-stone oceanographic transport and habitat continuity, using as model an ecosystem-structuring brown alga, Cystoseira amentacea var. stricta. To answer this question, we analysed the genetic structure and estimated the connectivity of populations along discontinuous rocky habitat patches in southern Italy, using microsatellite markers at multiple scales. In addition, we modelled the effect of rocky habitat continuity and ocean circulation on gene flow by simulating Lagrangian particle dispersal based on ocean surface currents allowing multigenerational stepping-stone dynamics. Populations were highly differentiated, at scales from few metres up to thousands of kilometres. The best possible model fit to explain the genetic results combined current direction, rocky habitat extension and distance along the coast among rocky sites. We conclude that a combination of variable suitable habitat and oceanographic transport is a useful predictor of genetic structure. This relationship provides insight into the mechanisms of dispersal and the role of life-history traits. Our results highlight the importance of spatially explicit modelling of stepping-stone dynamics and oceanographic directional transport coupled with habitat suitability, to better describe and predict marine population structure and differentiation. This study also suggests the appropriate spatial scales for the conservation, restoration and management of species that are increasingly affected by habitat modifications.MARES Grant (Doctoral Programme in Marine Ecosystem Health and Conservation) [EU-512002-1-2010-1-BE-EMJD]; Ghent University [FPA 2011-0016]; FCT (Portugal); project TETRIS; [SFRH/BPD/63703/2009]; [SFRH/BPD/107878/2015]; [SFRH/BPD/111003/2015]info:eu-repo/semantics/publishedVersio

Determining the influence of different atmospheric circulation patterns on PM10 chemical composition in a source apportionment study

This study combines a set of chemometric analyses with a source apportionment model for discriminating the weather conditions, local processes and remote contributions having an impact on particulate matter levels and chemical composition. The proposed approach was tested on PM10 data collected in a semi-rural coastal site near Venice (Italy). The PM10 mass, elemental composition and the water soluble inorganic ions were quantified and seven sources were identified and apportioned using the positive matrix factorization: sea spray, aged sea salt, mineral dust, mixed combustions, road traffic, secondary sulfate and secondary nitrate. The influence of weather conditions on PM10 composition and its sources was investigated and the importance of air temperature and relative humidity on secondary components was evaluated. Samples collected in days with similar atmospheric circulation patterns were clustered on the basis of wind speed and direction. Significant differences in PM10 levels and chemical composition pointed out that the production of sea salt is strongly depending on the intensity of local winds. Differently, typical primary pollutants (i.e. from combustion and road traffic) increased during slow wind regimes. External contributions were also investigated by clustering the backward trajectories of air masses. The increase of combustion and traffic-related pollutants was observed when air masses originated from Central and Northwestern Europe and secondary sulfate was observed to rise when air masses had passed over the Po Valley. Conversely, anthropogenic contributions dropped when the origin was in the Mediterranean area and Northern Europe. The chemometric approach adopted can discriminate the role local and external sources play in determining the level and composition of airborne particulate matter and points out the weather circumstances favoring the worst pollution conditions. It may be of significant help in designing local and national air pollution control strategies

Enriching the Italian Genuine Saving with water and soil depletion: National trends and regional differences

National and international governments aim to promote the responsible management of the natural capital but measuring its contribution to economic growth is still a challenging exercise. The natural capital supports a plurality of environmental functions whereas the economic growth is frequently measured by aggregated indicators. In this paper, we propose an extended version of the Genuine Saving macro indicator to account for water and soil depletion. Further, as natural capital is spatially heterogeneous we estimate Genuine Saving for Italy for the period 2000–2015 at the regional level. Whilst the case study produces specific results for Italy the methodological framework is broadly applicable to other states. The Italian comparison shows that soil and water provide an absolute change of roughly 1% of the GS but average relative regional variations are between 5 and 33% of GDP, showing that the geographical scale of sustainability analysis is a crucial element for responsible management of national assets. The methodological contribution suggests that the Genuine Saving can support policy makers in developing targeted policies for sustainable growth

Note Illustrative della Carta Geologica d’Italia alla scala 1:50000. Foglio 337 Norcia.

Non present