The predictive model of hydrobiological diversity in the Asana-Tumilaca basin, Peru based on water physicochemical parameters and sediment metal content

Abstract

The hydrobiological diversity in the basin depends on biotic and abiotic factors. A predictive model of hydrobiological diversity for periphyton and macrobenthos was developed through multiple linear regression analysis (MLRA) based on the physicochemical parameters of water (PPW) and metal content in sediments (MCS) from eight monitoring stations in the Asana-Tumilaca Basin during the dry and wet seasons. The electrical conductivity presented values between 47.9 and 3617 μS/cm, showing the highest value in the Capillune River due to the influence of geothermal waters. According to Piper's diagram, the water in the basin had a composition of calcium sulfate and calcium bicarbonate-sulfate. According to the Wilcox diagram, the water was found to be between good and very good quality, except for in the Capillune River. The Shannon-Wiener diversity indices (H') were 2.62 and 2.88 for periphyton, and 2.10 and 2.44 for macrobenthos, indicating moderate diversity; for the Pielou's evenness index (J'), they were 0.68 and 0.70 for periphyton, and 0.68 and 0.59 for macrobenthos, indicating similar equity, in the dry and wet seasons, respectively, for both indices. In the model there were three cases, where the first two cases only worked with PPW or MCS, and case 3 worked with PPW and MCS. For case 3, the predicted values for H' and J' of periphyton and macrobenthos concerning those observed presented correlation coefficients of 0.7437 and 0.6523 for periphyton and 0.9321 and 0.8570 for macrobenthos, respectively, which were better than those of cases 1 and 2. In addition, principal component analysis revealed that the As, Pb, and Zn contents in the sediments negatively influenced the diversity, uniformity, and richness of the macrobenthos. In contrast, Cu and Cr had positive impacts because of the adaptation processes.

Keywords: Glacial melt; Hydrochemistry; Taylor diagram; Volcanic soils; Weathering.

Fig. 1

Monitoring stations along the Asana-Tumilaca River Basin: Asana 1 (a), Altarani (b), Asana 2 (c), Asana 3 (d), Asana 4 (e), Charaque (f), Capillune (g), and Tumilaca (h).

Fig. 2

Flow chart for methodology and proposed models.

Fig. 3

Box-plot presentation of the global variability in a) physicochemical parameters of water, b) metal content in sediments, c) hydrobiological diversity indices in the Asana-Tumilaca Basin.

Fig. 4

Piper diagram of the water from the monitoring points in the Asana-Tumilaca Basin during the a) dry season (DS) and b) wet season (WS).

Fig. 5

The river water classification of the Asana-Tumilaca Basin according to the Wilcox diagram at the monitoring stations during the a) dry season (DS) and b) wet season (WS).

Fig. 6

Monitoring of snow cover in the Arundane and Chuquiananta mountain ranges during the a) dry season (DS) and b) wet season (WS).

Fig. 7

Shannon-Wiener diversity indices, Pielou's evenness, and richness of a) periphyton and b) macrobenthos at the monitoring stations Asana 1 (A), Altarani River (B), Asana 2 River (C), Asana 3 River (D), Asana 4 River (E), Charaque River (F), Capillune River (G), and Tumilaca River (H).

Fig. 8

Taxonomic composition of a) periphyton and b) macrobenthos at the monitoring stations Asana 1 (A), Altarani River (B), Asana 2 River (C), Asana 3 River (D), Asana 4 River (E), Charaque River (F), Capillune River (G), and Tumilaca River (H).

Fig. 9

Taylor diagram of the observed and predicted hydrobiological diversity indices of a) periphyton-H′, b) periphyton-J′, c) macrobenthos-H′, and d) macrobenthos-J’.

Fig. 10

PCA biplot of physicochemical composition of water (EC, DO, pH, T, HCO₃⁻, Cl⁻, SO₄²⁻, Ca, Mg, K, Na), metal content in sediments (As, Hg, Cd, Cu, Cr, Pb, Zn), and hydrobiological diversity indices (periphyton-H′, periphyton-J′, macrobenthos-H′, macrobenthos-J′).