Physical water column observations during summer breeze winds

During summer seasons (from 2012 to 2015) high resolution observation were performed in the Civitavecchia coastal area (Northern Tyrrhenian sea, west coast). All sampling was carried out from a small boat (5m rigid inflatable) starting in the early morning typically around 06:00 a.m. , and lasting from 2 to 8 h, depending on the weather conditions. The purposes of the experiment was to observe the variations of both the coastal circulation and the water column in response to rotation of 180 ° in the wind direction. During surveys both current measurements and yo-yo time series were performed. Current data were acquired using an ADCP SonTeck (500 Khz, sampling interval from 20sec to 60 sec, average interval 50% sampling, cell thickness 1 meter) and the yo-yo time series employing a small instrument package (CTD). The CTD contained an Idronaut 316 Plus and a SeaPoint fluorometer. The sampling rate for the CTD was 10Hz, profiling with the CTD was done by allowing the instrument package to free-fall, at an average descent rate of 1 m/s. During the summer 2012, the sampling plan consisted in four stations spaced a quarter of a mile (St. 1 - 10 m; St. 2 - 20 m; St. 3 - 30 m; and St. 4 - 40 m), in which yo-yo time series were performed with an interval of 20 min. In order to study fluorescence of Chlorophyll a pathes distribution in coastal zone. Breeze induced circulation was the goal of the following summers surveys, in these current measurements and yo-yo time series were performed moored at a depth of 40 m. Offshore station (St. 1 -40m) has been chosen to perform measurement, basis of previously observations (2012 sampling surveys). It was decided as wind driven circulation and mixing phenomena are less influenced by seabed than the other stations. Acquired data have been processed by NEMO SeaDataNet software.

Water chemistry and fluffy layer geochemistry and mineral content at four sites in the western Baltic Sea

The fluffy layer was sampled repeatedly during nine expeditions between October 1996 and December 1998 at four stations situated along a S-N-transect from the Oder Estuary to the Arkona Basin. Geochemical and mineralogical analyses of the fluff show regional differences (trends) in composition, attributed to provenance and to hydrographical conditions along their transport pathways. Temporal variability is very high at the shallow water station of the estuary, and decreases towards the deeper stations in the north. In the shallow water area, intensive resuspension of the fluff due to wind-driven waves and currents leads to an average residence time of only one to two days. Near-bottom lateral transport of the fluff is the main process that transfers the fine grained material, containing both nutrients and contaminants, from the coastal zone into the deeper basins of the Baltic Sea. Seasonal effects (e.g. biogenic production in relation to trace metal variation) are observed at the Tromper Wiek station, where the residence time of the fluffy material is in the scale of seasons. Thus, the fluffy layer offers suitable material for environmental monitoring programs.