Planothidium rostratum (Østrup) Lange-Bertalot (1999: 279)

Figs 7: AO–AP

Length: 13.9–14.1 µm; width: 5.2–5.8 µm; striae: 15 in 10 µm (n = 2)

Teratological form: deformed valve outline, with loss of transapical symmetry.

Occurrence: S3.

Ecological characteristics: Cond.: 42.00–50.00 µS cm –1; BOD: 1.43–2.38 mg L− 1; COD: 4.68–13.68 mg L− 1; N-NH: 323–680 mg L− 1; 3 − 1 − 1 − − 1 − 1 NO: 0.34–1.00 mg L; DO: 7.79–14.80 mg L; pH: 6.26–6.28; PO: 0.005 –0.006 mg L; TP: 0.007 –0.016 mg L; TS: 10.00– 3 4 11.00 mg L− 1; Temp.: 17.68–23.25 °C; Turb.: 10.30–10.40; Flow: 0.62–0.66 m 3 s; Average depth: 0.22–0.24 m; Prec.: 9.96 mm.

Metal concentrations: Co: 23.73–47.24 mg L –1; Cr: 27.33–80.86 mg L –1; Cu: 160.64–235.49 mg L- 1; Mn: 398.05–444.52 mg L –1; Ni: 27.57–69.89 mg L –1; Pb: 35.58–66.21 mg L –1; Zn: 78.97–167.31 mg L –1.