engleski

Early spring microphyte composition in Lake Jošava (Eastern Croatia)

Microphyte diversity (planktonic, epiphytic and epilithic) was investigated in the shallow Lake Jošava in early spring of 2018 at four different sampling stations (P1, P2, P3, P4). Higher concentrations of ammonium (0.12 mg/L), nitrites (0.06 mg/L), organic nitrogen (3.92 mg/L), total phosphorus (4.02 mg/L) and chlorophyll (Chl-a: 152.73 µg/L ; Chl-b: 47.74 µg/L ; Chl-c: 123.72 µg/L) were found at the shallowest part of the lake (P4) while higher concentrations of nitrates (2.54 mg/L) and total nitrogen (3.99 mg/L) were measured at the deepest part (P1). The lowest concentration of total phosphorus (0.42 mg/L) and total nitrogen (2.35 mg/L) was found at P3. In total, 137 microphytes were recorded in Lake Jošava. At all sampling stations, 60 phytoplankton species were found, with the highest diversity at P2 (44). The research showed high microphyte diversity (109) on stones at P1 (68) and reed at P2 (61). Hierarchical clustering showed a grouping of data according to various types of substrate. The most common microphytes were diatoms such as Cocconeis placentula, Navicula capitatoradiata and Cyclostephanos dubius. Increased concentrations of nutrients, high chlorophyll concentrations and high microphyte diversity indicate strong anthropogenic impact (traffic, livestock breeding, farming), especially in the shallower lake parts.

epilithon, epiphyton, eutrophication, phytoplankton

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