20 research outputs found
Circulation and horizontal fluxes in the northern Adriatic Sea in the period June 1999–July 2002. Part I: Geostrophic circulation and current measurement
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Changes in the northern Adriatic ecosystem and hypertrophic appearance of gelatinous aggregates
No full textMeteorological and oceanographic conditions in the northern Adriatic Sea during the period June 1999–July 2002: Influence on the mucilage phenomenon
No full textMucilage events (formation of very large organic aggregates and gelatinous surface layers) have been documented several times during the past two centuries in the northern Adriatic Sea (NA), while their frequency has significantly increased since 1988. In this work, meteorological and oceanographic conditions in the NA during the period June 1999–July 2002 are described and their relation to the outbreak and fate of the mucilage phenomenon was investigated. Salinity and temperature data were collected during approximately monthly cruises along three transects in the NA. Relevant meteorological situations (air temperature, rainfall, wind) were selected from large-scale ECMWF analyses and from the Local Analysis and Prediction System (LAPS; Emilia Romagna Meteorological Service), while sea conditions (waves) were analysed by means of the Wave Adriatic Model (WAM). Data for air temperature, rainfall, and wind from several meteorological stations in the region were used. Average seasonal cycles of sea temperature and salinity simulated with statistical models, based on historical data collected in the NA since 1972, were used to determine thermal and haline anomalies. The monthly anomaly variability of maximum and minimum air temperatures, rainfall amount and number of rainy days did not appear to be relevant for the mucilage phenomenon outbreak. In contrast, both vertical and horizontal thermohaline gradients in the region were more developed during late spring and summer of 2000 and particularly of 2002, when the mucilage events were of greatest extent in space and time, compared to 2001 (short-lived event) and 1999 (no event). These more pronounced gradients were due to a combination of several unusual conditions: sharp heating of the sea surface in May–June, domination of eastwards transport of freshened waters formed in the Po Delta area, and intrusion of very high salinity intermediate waters originating in the eastern Mediterranean. Moreover, in winter of both 2000 and 2002 very dense and cold water formed and remained in the bottom layer until spring, contributing to increase the stratification degree of the water column. The duration of the mucilage events and their spatial distribution in the region depend strongly on meteorological changes. Recurrent anticyclonic conditions, characterized by low wind and calm sea, favour extended events in time (up 2 months in 2002). In contrast, highly perturbed weather, particularly due to strong “bora” wind, can be determined in sharp decay of the event (e.g. in July 2000)
Circulation and horizontal fluxes in the northern Adriatic Sea in the period June 1999–July 2002. Part II: Nutrients transport
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RECENT TRENDS TOWARDS OLIGOTROPHICATION OF THE NORTHERN ADRIATIC: EVIDENCE FROM CHLOROPHYLL A TIME SERIES.
No full textPBS Report for Port of Rijeka. (Final Report). BALMAS project. Work package 5. Activity 5.1
No full textBallast water is proven to be one of the major vectors transporting invasive alien species (IAS) worldwide. Even harmful aquatic organisms are to be avoided in this manner of transfer. Port Baseline Surveys of the major ports along the Adriatic Sea are to enable efficient continuous monitoring and/or surveillance efforts in detection of new introduced species. Research of environmental conditions, flora and fauna community and circulation pattern in the port and wider area will enable better insight in possible fate of the new introduced species
Factors favouring phytoplankton blooms in the northern Adriatic: towards the northern Adriatic empirical ecological model
No full textInfluenced by one of the largest Mediterranean rivers, Po, the northern
Adriatic (NA) production is highly variable seasonally and interannually. The
changes are especially pronounced between winters and seemingly reflect on
total Adriatic bioproduction of certain species (anchovy). We analysed the
long-term changes in the phytoplankton production in the region, as derived
from monthly oceanographic cruises, in relation to concomitant geostrophic
currents distribution in the area and to Po River discharge rates in days
preceding the cruises. In winter and early spring the phytoplankton
abundances depended on existing circulation fields, in summer and autumn
they were related to Po River discharge rates 1–15 days earlier and on
concomitant circulation fields, while in late spring phytoplankton
abundances increased 1–3 days after high Po River discharge rates regardless
of the circulation fields. During the entire year the phytoplankton
abundances were dependent on forcing of the previous 1–12 months of surface
fluxes and/or Po River rates. The role of wind was uncertain but that was partly
due to unmatched sampling time frames between meteorological and sea data.
Low evaporation rates in November reflected significantly on the next
February circulation pattern and, although with somewhat lower significance,
on large phytoplankton blooms in the same month. We showed that the role of
wind in evaporative flux enhancements is not straightforward as
evaporative fluxes are highly dependent on other factors, e.g. air–sea
temperature difference. Wind-induced vertical mixing was only sporadically
related to phytoplankton abundances. From 1990 to 2004 a shift towards large
winter bioproduction induced by circulation changes appeared. The
investigations performed represent the preliminary actions in the construction of an empirical
ecological model of the NA which can be used in the sustainable economy of
the region, as well as for validation of the numerical ecological model of
the region, which is currently being developed
PBS Report for Port of Pula. (Final Report). BALMAS project. Work package 5. Activity 5.1
No full textBallast water is proven te be one of the major vectors transporting invasive alien species (IAS)
worldwide. Even harmful aquatic organisms are to be avoided in this manner of transfer. Port
Baseline Surveys of the major ports along the Adriatic Sea are to enable efficient continuous
monitoring and/or surveillance efforts in detection of new introduced species. Research of
environmental conditions, flora and fauna community and circulation pattern in the port and
wider area will enable better insight in possible fate of the new introduced species
