EGU21-5793
https://doi.org/10.5194/egusphere-egu21-5793
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Climatology of dust deposition in the Adriatic Sea and biological response of Rogoznica Lake (central Adriatic)

Boris Mifka1, Irena Ciglenečki2, and Maja Telišman Prtenjak3
Boris Mifka et al.
  • 1Department of Physics, University of Rijeka, Rijeka (boris.mifka@phy.uniri.hr)
  • 2Ruđer Bošković Institute, Division for Marine and Environmental Research, Zagreb (Irena.Ciglenecki-Jusic@irb.hr)
  • 3University of Zagreb, Faculty of Science, Department of Geophysics, Zagreb, Croatia (telisman@gfz.hr)

Airborne desert dust is one of the most abundant aerosols and an important factor in climate
change. After deposition in the sea, mineral dust acts as the nutrient. In this study, the climatology
of desert dust deposition in the Adriatic Sea was investigated with special reference to the possible
source and mineralogical characteristics of transported dust from North Africa. The effect is
particularly examined in unique, isolated marine system, Rogoznica Lake (RL; 43° 32 ’N, 15° 58’
E) through its biological response.
For that purpose, the MERRA-2 reanalysis data for dust deposition in the period 1989-
2019 were used. Annual dust deposition cycle in the Adriatic Sea has maximum in spring and fall
with stronger deposition in central and south. Wet deposition accounts for 63-92% of total
deposition and 75% of data contains less than 1.5% of the mass. Intensity classes are defined for
the remaining 25% and each refers to about 30% of the mass. On average, over 73 days per year
is of weak, 14.6 of moderate, and 3.65 of extreme intensity, which varies spatially. In order to
detect the specific synoptic patterns for the dust transport in relation to the dust sources activity
and deposition in the Adriatic Sea, the EOF analysis on 850 hPa was utilized. Positive or negative
mode phases correspond to deposition anomalies in the Adriatic Sea and can be related to particular
dust sources in North Africa.
Given the seasonal strong physicochemical stratification, relatively small volume, and only
source of freshwater and nutrients through precipitation during stratification, the Rogoznica Lake
proved ideal for monitoring desert dust deposition events, by monitoring nutrient concentration in
the surface layer (0–2 m). For the 2000-2012 period no correlation with MERRA-2 deposition
time series were found, but biological activity as a direct consequence of nutrient increase was
observed during deposition events. Since the Adriatic Sea was proved to be phosphate (P) and iron
(Fe) limited, the mineralogical database was used to estimate the amount of deposited P and Fe
during intense deposition events.

How to cite: Mifka, B., Ciglenečki, I., and Telišman Prtenjak, M.: Climatology of dust deposition in the Adriatic Sea and biological response of Rogoznica Lake (central Adriatic), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5793, https://doi.org/10.5194/egusphere-egu21-5793, 2021.

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