Gomphonema graciledictum E. Reichardt (2015: 373)

Figs 6: W–Y

Length: 33.2–67.7 µm; width: 6.9–9 µm; striae: 11–13 in 10 µm (n = 7)

Teratological form: deformed valve outline, with bent apices. Unusual striae pattern, throughout the valve or strongly radiate in the median portion of the valve.

Occurrence: S3.

Ecological characteristics: Cond.: 50.00–53.00 µS cm –1; BOD: 0.89–3.27 mg L− 1; COD: 7.23–13.60 mg L− 1; N-NH: 316–378 µg L− 1; 3 − 1 − 1 − − 1 − 1 NO: 0.34–0.37 mg L; DO: 11.42–14.80 mg L; pH: 5,79–6.26; PO: 0.005 –0.008 mg L; TP: 0.009 –0.017 mg L; TS: 10.00– 3 4 66.00 mg L− 1; Temp.: 17.40–17.68 °C; Turb.: 7.03–10.70; Flow: 0.47–0.62 m 3 s; Average depth: 0.19–0.24 m; Prec.: 9.96 mm.

Metal concentrations: Co: 23.91–33.57 mg L –1; Cr: 27.33–78.86 mg L –1; Cu: 197.55–235.49 mg L- 1; Mn: 398.50–444.52 mg L –1; Ni: 31.80–69.89 mg L –1; Pb: 35.58–46.56 mg L –1; Zn: 93.81–167.31 mg L –1.