scholarly journals A Generalization of the TRIX trophic index to the Adriatic Sea basin

2016 ◽  
Author(s):  
Emanuela Fiori ◽  
Marco Zavatarelli ◽  
Nadia Pinardi ◽  
Cristina Mazziotti ◽  
Carla Rita Ferrari

Abstract. The Marine Strategy Framework Directive is pushing for new methodological approaches in order to protect the marine environment more effectively. The trophic index TRIX was developed by Vollenweider in 1998 for the coastal area of Emilia-Romagna (northern Adriatic Sea), and was exploited by Italian legislation to characterize the trophic state of coastal waters. In order to implement TRIX in different areas and for different time periods, we developed a methodology for the generalization of the index changing the scaling parameters. We compared the TRIX index calculated from in situ data ("in situ TRIX") with the corresponding index simulated with a coupled physics and biogeochemical numerical model ("model TRIX") implemented in the overall Adriatic Sea. The comparison between in situ and simulated data was carried out for a data time series in the Emilia-Romagna coastal strip. This study demonstrates the compatibility of the model with the in situ TRIX and the necessity to have time series longer than 10 years to evaluate properly the scaling parameters. The model TRIX is finally calculated for the whole Adriatic Sea showing trophic index differences across the Adriatic coastal areas.

2016 ◽  
Vol 16 (9) ◽  
pp. 2043-2054 ◽  
Author(s):  
Emanuela Fiori ◽  
Marco Zavatarelli ◽  
Nadia Pinardi ◽  
Cristina Mazziotti ◽  
Carla Rita Ferrari

Abstract. The main scope of the Marine Strategy Framework Directive is to achieve good environmental status (GES) of the EU's marine waters by 2020, in order to protect the marine environment more effectively. The trophic index (TRIX) was developed by Vollenweider in 1998 for the coastal area of Emilia-Romagna (northern Adriatic Sea) and was used by the Italian legislation to characterize the trophic state of coastal waters. We compared the TRIX index calculated from in situ data (“in situ TRIX”) with the corresponding index simulated with a coupled physics and biogeochemical numerical model (“model TRIX”) implemented in the overall Adriatic Sea. The comparison between in situ and simulated data was carried out for a data time series on the Emilia-Romagna coastal strip. This study shows the compatibility of the model with the in situ TRIX and the importance of the length of the time series in order to get robust index estimates. The model TRIX is finally calculated for the whole Adriatic Sea, showing trophic index differences across the Adriatic coastal areas.


2014 ◽  
Vol 11 (6) ◽  
pp. 3003-3034 ◽  
Author(s):  
G. Zibordi ◽  
F. Mélin ◽  
J.-F. Berthon ◽  
M. Talone

Abstract. The accuracy of primary satellite ocean color data products from the Moderate Resolution Imaging Spectroradiometer on-board Aqua (MODIS-A) and the Visible/Infrared Imager/Radiometer Suite (VIIRS), is investigated in the Western Black Sea using in situ measurements from the Gloria site included in the Ocean Color component of the Aerosol Robotic Network (AERONET-OC). The analysis is also extended to an additional well-established AERONET-OC site in the northern Adriatic Sea characterized by optically complex coastal waters exhibiting similarities with those observed at the Gloria site. Results from the comparison of normalized-water leaving radiance LWN indicate biases of a few percent between satellite derived and in situ data at the center-wavelengths relevant for the determination of chlorophyll a concentration (443–547 nm, or equivalent). Remarkable is the consistency among the annual cycle determined with time series of satellite-derived and in situ LWN ratios at these center-wavelengths. Contrarily, the differences between in situ and satellite-derived LWN are pronounced at the blue (i.e., 412 nm) and red (i.e., 667 nm, or equivalent) center-wavelengths, suggesting difficulties in confidently applying satellite-derived radiometric data from these spectral regions for quantitative analysis in optically complex waters.


2019 ◽  
Author(s):  
Ivica Vilibić ◽  
Petra Zemunik ◽  
Jadranka Šepic ◽  
Natalija Dunić ◽  
Oussama Marzouk ◽  
...  

Abstract. The paper documents seasonality, interannual to decadal variability and trends in temperature, salinity and density over a transect in the shallow northern Adriatic Sea (Mediterranean Sea) between 1979 and 2017. Amplitude of seasonality decreases with depth, and is much larger in temperature and density than in salinity. Interannual to decadal variability in temperature and salinity are differently correlated in surface and bottom layers, indicating different mechanisms which govern their variability. Trends in temperature are large (up to 6 °C over 100 years), significant through the area and not sensitive to the sampling interval and time series length. In contrast, trends in salinity are largely weak and insignificant and depend on the time series length. The warming of the area is stronger during spring and summer. Such large temperature trends and their spatial variability indicate substantial changes in the thermohaline circulation in this area known as a dense water formation site, with a potential to affect biogeochemical and ecological properties of the whole Adriatic Sea.


Harmful Algae ◽  
2020 ◽  
Vol 93 ◽  
pp. 101773 ◽  
Author(s):  
Timotej Turk Dermastia ◽  
Federica Cerino ◽  
David Stanković ◽  
Janja Francé ◽  
Andreja Ramšak ◽  
...  

2000 ◽  
Vol 42 (1-2) ◽  
pp. 299-304 ◽  
Author(s):  
N. Penna ◽  
S. Berluti ◽  
A. Penna ◽  
F. Ridolfi

The presence of large mucilaginous masses, referred to as mucilage or with the traditional term “dirty sea”, has led to serious problems for the tourism and fishing industries along the coast of the northern Adriatic Sea. Using a cable-guided telecamera, these masses were observed in situ from the water surface along the water column to the sea bottom, with the aim of better understanding the appearance of the mucilage, its formation and dispersion and the processes originated by phytoplankton involved in this phenomenon. Furthermore, we sought information to help explain the fact that the appearance of mucilage does not tend to lead to anoxia in the surrounding water and that the mucilage seemed to containhuge amounts of iron. The chemical-physical characteristics of mucilage samples and samples of the surrounding water were studied. Further studies of their composition were carried out to determine the levels of organic matter, organic carbon, carbohydrates and heavy metals.


Ocean Science ◽  
2019 ◽  
Vol 15 (5) ◽  
pp. 1351-1362 ◽  
Author(s):  
Ivica Vilibić ◽  
Petra Zemunik ◽  
Jadranka Šepić ◽  
Natalija Dunić ◽  
Oussama Marzouk ◽  
...  

Abstract. The paper documents seasonality, interannual-to-decadal variability, and trends in temperature, salinity, and density over a transect in the shallow northern Adriatic Sea (Mediterranean Sea) between 1979 and 2017. The amplitude of seasonality decreases with depth and is much larger in temperature and density than in salinity. Time series of temperature and salinity are correlated in the surface but not in the bottom layer. Trends in temperature are large (up to 0.6 ∘C over 10 years), significant through the area, and not sensitive to the sampling interval and time series length. In contrast, trends in salinity are largely small and insignificant and depend on the time series length. The warming of the area is more during spring and summer. Such large temperature trends and their spatial variability emphasize the importance of maintaining regular long-term observations for the proper estimation of thermohaline trends and their variability. This is particularly important in regions which are key for driving thermohaline circulation such as the northern Adriatic, with the potential to affect biogeochemical and ecological properties of the whole Adriatic Sea.


2014 ◽  
Vol 71 (7) ◽  
pp. 1593-1603 ◽  
Author(s):  
Alberto Barausse ◽  
Vittoria Correale ◽  
Aleksia Curkovic ◽  
Licia Finotto ◽  
Emilio Riginella ◽  
...  

Abstract Elasmobranch populations are declining worldwide, calling for urgent assessment of fishery exploitation and application of effective conservation strategies. Here, we applied a novel approach, integrating long-term time-series of landings (1945–2012) and extensive surveys at the fish market of Chioggia, Italy, home of the major fishing fleet of the northern Adriatic Sea, to evaluate the status of elasmobranch populations and fisheries in the one of the most fished Mediterranean basins. The time-series highlight a dramatic decline in elasmobranch landings, particularly for skates and catsharks (Scyliorhinus spp.), whose current catch rates are 2.4 and 10.6% of the average 1940s levels, respectively. These data likely reflect similar large reductions in abundance, as indicated by the analysis of catch-per unit-effort time-series. The biomass of landed skates and catsharks showed regular fluctuations that disappeared after the collapse of the landings. Elasmobranch market composition, assessed through the sampling of 11 900 specimens from 2006 to 2013, included 14 species, but was dominated by just two: Mustelus mustelus and M. punctulatus, which represented more than 60% of the catch. The proportion of sexually immature individuals was generally very high, up to 83% of landed females and 71% of landed males, depending on the species. Although some correlations were detected between landings and local hydrography or climatic indices, the analyses of landings and surveys at the fish market identified fishery exploitation as the main driver of the striking, long-term elasmobranch decline in the northern Adriatic Sea, calling for urgent management actions to improve the conservation status of these fish.


Ocean Science ◽  
2015 ◽  
Vol 11 (2) ◽  
pp. 275-286 ◽  
Author(s):  
G. Zibordi ◽  
F. Mélin ◽  
J.-F. Berthon ◽  
M. Talone

Abstract. The accuracy of primary satellite ocean color data products from the Moderate Resolution Imaging Spectroradiometer on-board Aqua (MODIS-A) and the Visible/Infrared Imager/Radiometer Suite (VIIRS) is investigated in the Western Black Sea using in situ measurements from the Gloria site included in the ocean color component of the Aerosol Robotic Network (AERONET-OC). The analysis is also extended to an additional well-established AERONET-OC site in the northern Adriatic Sea characterized by optically complex coastal waters exhibiting similarities to those observed at the Gloria site. Results from the comparison of normalized water-leaving radiance LWN indicate biases of a few percent between satellite-derived and in situ data at the center wavelengths relevant for the determination of chlorophyll a concentrations (443–547 nm, or equivalent). Remarkable is the consistency between the annual cycle determined with time series of satellite-derived and in situ LWN ratios at these center wavelengths. Contrarily, the differences between in situ and satellite-derived LWN are pronounced at the blue (i.e., 412 nm) and red (i.e., 667 nm, or equivalent) center wavelengths, confirming difficulties in confidently applying satellite-derived radiometric data from these spectral regions for quantitative analysis in optically complex waters.


Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2810
Author(s):  
Fabrizio Bernardi Aubry ◽  
Francesco Acri ◽  
Gian Marco Scarpa ◽  
Federica Braga

The coexistence of phytoplankton and macrophytes in the Lagoon of Venice (Northern Adriatic Sea, Italy) was investigated using in situ data collected monthly as part of International Long Term Ecosystem Research (LTER), together with satellite imagery for the period 1998–2017. The concentrations of chlorophyll a and hydrochemical parameters were measured in three areas of the lagoon, where the expansion of well-developed stands of submerged vegetation was observed by remote sensing. Our results suggest interaction between phytoplankton and macrophytes (macroalgae and seagrasses) in the last few years of the time series, evidenced by decreasing chlorophyll a concentrations in the vicinity of the macrophyte stands. The integration of LTER and remotely sensed data made it possible to evaluate the interaction of macrophytes and phytoplankton at the ecosystem scale for the first time in the Lagoon of Venice.


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