scholarly journals Seasonal and Interannual Trends of Oceanographic Parameters over 40 Years in the Northern Adriatic Sea in Relation to Nutrient Loadings Using the EMODnet Chemistry Data Portal

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2280 ◽  
Author(s):  
Federica Grilli ◽  
Stefano Accoroni ◽  
Francesco Acri ◽  
Fabrizio Bernardi Aubry ◽  
Caterina Bergami ◽  
...  
Keyword(s):  
Climate Changes ◽  
Management Practices ◽  
Adriatic Sea ◽  
Nutrient Concentrations ◽  
Data Series ◽  
Mean Flow ◽  
Northern Adriatic Sea ◽  
Po River ◽  
Northern Adriatic

Long-term data series (1971–2015) of physical and biogeochemical parameters were analyzed in order to assess trends and variability of oceanographic conditions in the northern Adriatic Sea (NAS), a mid-latitude shallow continental shelf strongly impacted by river discharges, human activities and climate changes. Interpolation maps and statistical models were applied to investigate seasonal and spatial variability, as well as decadal trends of temperature, salinity, chlorophyll-a and nutrients. This analysis shows that sea surface temperature increased by +0.36% year−1 over four decades. Annual mean flow of the Po River markedly changed due to the occurrence of periods of persistent drought, whereas the frequency of flow rates higher than 3000 m3 s−1 decreased between 2006 and 2015. Moreover, we observed a long-term decrease in surface phosphate concentrations in Po River water (−1.34% year−1) and in seawater (in summer −2.56% year−1) coupled, however, to a significant increase in nitrate concentration in seawater (+3.80% year−1) in almost all seasons. These changes indicate that the nutrient concentrations in the NAS have been largely modulated, in the last forty years, by the evolution of environmental management practices and of the runoff. This implies that further alteration of the marine environment must be expected as a consequence of the climate changes.

scholarly journals Spatial and seasonal variability of fractionated phytoplankton biomass and primary production in the frontal region of the Northern Adriatic Sea

2005 ◽  
Vol 6 (1) ◽  
pp. 5 ◽  
Author(s):  
M.R. VADRUCCI ◽  
G. CATALANO ◽  
A. BASSET
Keyword(s):  
Primary Production ◽  
Phytoplankton Biomass ◽  
Adriatic Sea ◽  
Size Structure ◽  
Nutrient Concentrations ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Frontal System ◽  
Dissolved Phosphorus ◽  
Point Total

Spatial and seasonal patterns of variation of fractionated phytoplankton biomass and primary production and their relationships with nutrient concentrations were analyzed along an inshore - offshore gradient and in relation to the presence of a frontal system in the Northern Adriatic Sea. Sampling was carried out in winter and summer during four oceanographic cruises (June 1996 and 1997, February 1997 and 1998) as part of the PRISMA II project. Water samples for determining nutrient concentrations, phytoplankton biomass (as Chla) and primary production (as 14 C assimilation) were collected at five optical depths. Sampling stations were located along 2 or 4 parallel transects arranged perpendicularly to the shoreline and the frontal system. The transects were located at such a distance from the coast that the frontal system crossed them at their halfway point. Total dissolved nitrogen (TDN) and total dissolved phosphorus concentrations (TDP) were 12.41 ± 3 .95 mM and 0.146 ± 0 .070 mM, respectively. The values in the two seasonal periods were similar, decreasing along the inshore-offshore gradient. Values for phytoplankton biomass and primary productionwere higher in the winter than the summer cruises, and decreased, in both seasonal periods, along the inshore / offshore gradient. Moreover, in both seasonal periods, picophytoplankton dominated both biomass and productivity, (56% and 44%, respectively) at stations beyond the frontal system, while microphytoplankton was more important at stations inside it (44% and 44%, respectively). Total phytoplankton biomass and primary production were directly related to nutrient concentrations. Regarding size classes, significant patterns of variation with nutrients were observed particularly for biomass. The results indicate that the size structure and function of phytoplankton guilds seem to be mediated by nutrient inflow, as well as by competitive interaction among size fractions.

scholarly journals Long-term changes in hydrographic conditions in northern Adriatic and its relationship to hydrological and atmospheric processes

2004 ◽  
Vol 22 (3) ◽  
pp. 733-745 ◽  
Author(s):  
N. Supić ◽  
B. Grbec ◽  
I. Vilibić ◽  
I. Ivančić
Keyword(s):  
Discharge Rate ◽  
Time Lag ◽  
Data Series ◽  
Time Lags ◽  
Po River ◽  
Northern Adriatic ◽  
Nao Index ◽  
Mediterranean Oscillation ◽  
Yearly Means

Abstract. A very long data series (1921–2000) of hydrographic parameters (temperature, salinity and density) collected in surface and bottom layers at a station in the coastal zone in the northeastern Adriatic was analyzed. Seasonal and interannual variability of the three parameters is described on the basis of monthly and yearly averages. The seasonal cycles obtained were found to be typical for the northern Adriatic. Interannual analysis showed that there was no trend in temperature, salinity and density in the region during the interval analyzed. The long-term series of yearly means of hydrographic parameters were related to the long-term series of yearly means of several hydrological/atmospheric parameters using different time lags of between 0 and 4 years. These parameters are surface heat flux gained by insolation Qs computed for Trieste, precipitation P in Trieste, Po River discharge rate R and two atmospheric oscillation indexes, a Mediterranean Oscillation (MO) index and North Atlantic Oscillation (NAO) index. At zero time lag the interannual changes at the surface were found to be significantly related to changes in the Qs and NAO index (temperature) and R (salinity and density). At the same time lag the changes in the bottom were found to be related to the MO index (temperature, salinity and density). Additionally, bottom salinity and density were significantly related to R at a time lag of 1 year. Key words. Oceanography: Physical (air-sea interactions; hydrography)

scholarly journals Climatic and Anthropogenic Impacts on Environmental Conditions and Phytoplankton Community in the Gulf of Trieste (Northern Adriatic Sea)

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2652 ◽  
Author(s):  
Stefano Cozzi ◽  
Marina Cabrini ◽  
Martina Kralj ◽  
Cinzia De Vittor ◽  
Massimo Celio ◽  
...  
Keyword(s):  
Management Practices ◽  
Phytoplankton Community ◽  
Anthropogenic Impacts ◽  
Nutrient Balance ◽  
Environmental Data ◽  
Data Series ◽  
Nutrient Loads ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Gulf Of Trieste

During the last century, human activities have exerted an increasing pressure on coastal ecosystems, primarily inducing their eutrophication, with a more recent partial mitigation of this phenomenon where improvements of environmental management practices were adopted. However, a reanalysis of the pressures on coastal zones and surrounding drainage basins is needed because of the alterations induced nowadays by the climate changes. A comparative analysis of long-term oceanographic and environmental data series (1986–2018) was performed, in order to highlight the effects of anthropogenic and climatic disturbances on the phytoplankton community in the Gulf of Trieste (GoT). After the 1980s, the decline in phytoplankton abundance was matched to increasing periods of low runoff, an overall deficit of the precipitation and to a decrease in phosphate availability in the coastal waters (−0.003 µmol L−1 yr−1), even in the presence of large riverine inputs of nitrogen and silicates. This trend of oligotrophication was reversed in the 2010s by the beginning of a new and unexpected phase of climatic instability, which also caused changes of the composition and seasonal cycle of the phytoplankton community. Beyond the management of nutrient loads, it was shown that climatic drivers such as seawater warming, precipitation and wind regime affect both nutrient balance and phytoplankton community in this coastal zone.

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