Rogoznica Lake, a Euxinic Marine Lake on the Adriatic Coast (Croatia) that Fluctuates Between Anoxic Holomictic and Meromictic Conditions

The biogeochemistry of ferruginous lakes and past ferruginous oceans

“…Several natural processes could produce a basin with Zr ≥ 4 %, which -as described above -might poise a lake to develop meromixis. Lake basins carved in karstic terrain can be quite deep relative to their surface area, and many meromictic lakes are known from karstic regions (Alcocer, 2017;Ciglenečki et al, 2017), including ferruginous La Cruz in Spain (Camacho et al, 2017a). Morphometry resulting in high Zr and meromixis is sometimes attributed to faulting in exposed bedrock that has been weathered or further carved by glacial ice or outwash.…”

Electrochemical Evidence of non-Volatile Reduced Sulfur Species in Water-Soluble Fraction of Fine Marine Aerosols

“…Two types of non-volatile RSS peaks were detected and attributed to the presence of mercapto-type (RS-Hg peak at around −0.6 V and positive, calibrated with 3-MPA) and sulfide/S 0 -like compounds (HgS peak more negative than −0.6 V, calibrated with sulfide). In spring samples only, the presence of the mercapto-type compounds was evident and proved by the addition of the standard 3-MPA, ranging from 2.60 to 15.40 ng m −3 , while both, the mercapto-type (0.48-2.23 ng m −3 ) and sulfide and/or S 0 -like compounds (0.02-0.26 ng m −3 ) were detected in early autumn samples collected during anoxic holomictic event [44] in the nearby marine lake water column.…”

“…The appearance of the negative HgS peak in autumn samples could be likely associated with enhanced release of volatile S compounds during water layer mixing in the nearby marine Rogoznica Lake [44]. That is, during intense vertical lake water layers mixing, millimolar concentrations of sulfide present in the anoxic bottom layer reach the surface where it is rapidly oxidized (mainly to S 0 ) and further lost into the atmosphere.…”

Climatology of Dust Deposition in the Adriatic Sea; a Possible Impact on Marine Production

“…RL is known as a site with high biological and microbiological activities, that is, high levels of primary and secondary production (Čanković et al., 2019; Ciglenečki et al., 2017); however, extreme values for water column oxygen saturation (200%–300%) have been measured occasionally (Ciglenečki et al., 2005; Ćosović et al., 2000). All these events have been already discussed in relation to nano‐ and pico‐planktonic blooms (Ćosović et al., 2000; Šestanović et al., 2005), as well as microphytoplankton ( Chaetoceros curvisetus and Prorocentrum arcuatum ) and mixotrophic activities (microflagellates Hermesinum adriaticum, and Ceratium furca occurrences, Burić et al., 2009; Svensen et al., 2008), which are known to be connected with the input of extra nutrient sources (Nodwell & Price, 2001; Nygaard & Tobiesen, 1993).…”

“…Interannual variability in dust deposition is also analyzed using average values for the investigated area. Additionally, the central Adriatic marine system of Rogoznica Lake (RL) (43°32'N, 15°58'E), as a site with stable seasonal physicochemical stratification, atmospheric input as the only source of freshwater (Ciglenečki et al, 2015(Ciglenečki et al, , 2017Čanković et al, 2019), and relatively short residence time of trace metals (Fe, Mo) in the water column due to interaction with sulfide (Helz et al, 2011), is taken to prove the effect of dust deposition on primary production.…”