Plankton crustaceans in bays with different trophic status in Llanquihue lake (41° S Chile)

Abstract

The Llanquihue lake is included in the called Araucanian or Nord Patagonian lakes located between 38-41° S. These lakes are characterized by their oligo-mesotrophic status due to human intervention which takes to the increase in nutrients inputs from industries and towns. Effects on zooplankton assemblages are observed with marked increase of daphnids abundance. The aim of the present study is to analyze the trophic status and zooplankton relative abundance in different bays of Llanquihue lake. It was found direct associations between chlorophyll a with daphnids percentage, total dissolved nitrogen with reactive soluble phosphorus nitrogen/phosphorus molar radio with cyclopoids percentage, and an inverse relation between daphnids and calanoids percentages. The occurrence of three kinds of microcrustacean assemblages and environmental conditions was evidenced: the first one with high calanoids percentage, low species number and low chlorophyll and nutrients concentration, a second with moderate chlorophyll and nutrients concentration and moderate daphnids percentage; high species number and a third site with high chlorophyll and nutrients concentration, high daphnids percentage and high species number. Daphnids increase under mesotrophic status, agree with similar results observed for southern Argentinean and New Zealand lakes.

Associations between spectral properties, bacteriological characteristics, chlorophyll and zooplankton communities in two north Patagonian lakes

“…The results revealed the presence of differences in water quality, in term of bacterial abundances, chlorophyll concentrations and spectral properties, between the two lakes, and within each lake, that agree with the first observations for Caburgua and Lake Villarricas (De los Ríos-Escalante et al, 2020a), and probably are applicable for other northern Patagonian lakes such as Llanquihue, located at 41°S (De los Ríos-Escalante et al, 2017). The present results show that the integration of limnological descriptions and remote-sensing techniques for Chilean lakes can serve to propose a predictive model based on LANDSAT 8 OLI sensor images (De los Ríos-Escalante et al, 2020).…”

“…A different situation occurs with Lake Villarrica, that is oligo-mesotrophic, as a function of the changes in the surrounding basins of the respective bays (De los Ríos-Escalante et al, 2020); such environmental variation within a lake was described also for Llanquihue lake (De los Ríos-Escalante et al, 2017). The results obtained for Lake Villarrica in the present study, that include the role of species abundances, indicates that an increase in chlorophyll is related to the absence of mixotrophic ciliates, as a result of predation by cyclopoid copepods (Kamjunke et al, 2009(Kamjunke et al, , 2012.…”

“…Some of these lakes in Chile have marked human interventions in their surrounding basins, due agriculture or forestry activities, and towns on their shores (De los Ríos-Escalante et al, 2017, 2020. These alterations, due to the replacement of native forest with agriculture, forestry and towns, generate an increase of the nutrient inputs from the basin to the lake with consequent chlorophyll increase in some specific sites of the lake, such as small bays (Woelfl et al, 2010;De los Ríos-Escalante et al, 2017, 2020.…”

“…Some of these lakes in Chile have marked human interventions in their surrounding basins, due agriculture or forestry activities, and towns on their shores (De los Ríos-Escalante et al, 2017, 2020. These alterations, due to the replacement of native forest with agriculture, forestry and towns, generate an increase of the nutrient inputs from the basin to the lake with consequent chlorophyll increase in some specific sites of the lake, such as small bays (Woelfl et al, 2010;De los Ríos-Escalante et al, 2017, 2020. Similar results had been reported for Llanquihue lake (41°S, Chile), where chlorophyll was described together with variations in nutrients and chlorophyll concentrations in groups of sites with towns, aquaculture activities and unaltered sites (De los Ríos-Escalante et al, 2017), and for Lake Villarrica with two bays with towns, and sites with very low human intervention (De los Ríos-Escalante et al, 2020.…”