1. Signatures of pigments and processes in the south Adriatic Pit - project MEDUZAMira Morović, Vesna Flander-Putrle, Davor Lučić, Branka Grbec, Barbara Gangai, Alenka Malej, Frano Matić, 2012, original scientific article Abstract: During two cruises of the MEDUZA experiment conducted in July 2003 and May 2005 various data were obtained over the deepest part of the southern Adriatic Pit. Temperature, salinity, light transmission and fluorescence were measured in July 2003. During May 2005, except CTD measure- ments the samples were taken for laboratory determination of phytoplankton pigments with HPLC technique. During both cruises irradiance and radiance were measured at 14 wavelengths in the range 340-715 nm with optical probe to about 100 m depth. Bad weather conditions during both cruises caused interruption of measurements that continued after 24 to 48 hours. Stormy conditions have resulted in a slightly different structure of the water column. In the periods of measurements recorded were diurnal rhythms in a series of parameters, caused by solar radiation cycles in the surface layers as well as fluctuations in the deeper layers under the influence of the internal tide. Meteorological conditions and changes in sea level are also described. The analysis included the principal component and correlation analysis between the measured and derived parameters in order to establish a link between the in-situ pigments and multispectral data. During both cruises diurnal vertical oscillations were observed in biotic and abiotic parameters. Chlorophyll pigments prevailed over other pigments preventing other pigments to be distinguished spectrally. Regression models for chlorophyll a were established from radiance and reflectance ratios.
Keywords: termohaline properties, vertical migrations, Adriatic, South Adriatic Sea, diurnal rhithm, open sea, internal tide, Adriatic
Published in DiRROS: 05.08.2024; Views: 10; Downloads: 8
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2. Phytoplankton assemblage over a 14-year period in the Adriatic Sea : patterns and trendsSanda Skejić, Blanka Milić Roje, Frano Matić, Jasna Arapov, Janja Francé, Mia Bužančić, Ana Bakrač, Maja Straka, Živana Ninčević Gladan, 2024, original scientific article Abstract: Considering the role of phytoplankton in the functioning and health of marine systems, it is important to characterize its responses to a changing environment. The central Adriatic Sea, as a generally oligotrophic area, is a suitable environment to distinguish between regular fluctuations in phytoplankton and those caused by anthropogenic or climatic influences. This study provides a long-term perspective of phytoplankton assemblage in the central eastern Adriatic Sea, with 14 years of continuous time series data collected at two coastal and two offshore stations. The predominant phytoplankton groups were diatoms and phytoflagellates, but their proportion varied depending on the vicinity of the coast, as evidenced also by the distribution of chlorophyll a. In the coastal environment, the phytoplankton biomass was substantially higher, with a higher proportion of microphytoplankton, while small phytoplankton accounted for the majority of biomass in the offshore area. In addition, a decreasing trend in diatom abundance was observed in the coastal waters, while such trend was not so evident in the offshore area. Using a neural gas algorithm, five clusters were defined based on the contribution of the major groups. The observed increase in diversity, especially in dinoflagellates, which outnumber diatom taxa, could be a possible adaptation of dinoflagellates to the increased natural solar radiation in summer and the increased sea surface temperature.
Keywords: phytoplankton community, long-term data, diversity, chlorophyll a, neural gas analysis, solar radiation, Adriatic Sea
Published in DiRROS: 11.07.2024; Views: 114; Downloads: 55
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