Limnological Observations and Primary Production of Haft Barm Lakes, Fars Province, Iran Limnology of Haft Barm Lake

Haft Barm is a series of five small lakes in the southern Zagros region which has encountered recent rapid development of human settlement. This article reports a survey on its essential ecological attributes.

Water samples were taken from three locations in March and June 2020 and analyzed regarding physical and chemical factors and plankton communities. Trophic state and primary production were estimated.

Results showed water temperature 8.2–23.1 °C, dissolved oxygen 6.3–8.3 mg.L-1, salinity as electrical conductivity 739 – 971 µS.cm-1, total nitrogen 0.1–1.1 mg.L-1, and total phosphorus 0.4 and 3.8 mg.L-1. Algae of the lake consisted of 24 taxa, the highest density of which counted 23360 cells per liter in June, and the Chlorophyceae were the dominant group. The Zooplankton composition was of four taxa from Cladocera (Bosmina sp. and Daphnia sp.), Copepoda (Cyclops sp.), and Rotifera (Rotaria sp.), with the highest densities in Rotaria (35 individuals per liter). Phragmites sp., and Juncus sp. were the dominant species in the macrophyte community besides Polygonum amphbium, and Potamogeton pectiatus. The very high concentration of total phosphorus is a strong sign for predicting a eutrophic condition. The average trophic index is estimated at 88, which suggests a eutrophic to hyper-eutrophic state for the lake. The estimated primary production of the lake was 1114 gC.m-2.A-1.