Bioeksperimen
Vol. 12 No. 2: September 2026

Daily dynamics and structure of zooplankton communities as bioindicators in Merdada Lake, Dieng Plateau, Central Java, Indonesia

Wahyu Febriani (Program Ilmu Lingkungan, Sekolah Pascasarjana, Universitas Gadjah Mada, Yogyakarta)
Suwarno Hadisusanto (Faculty of Biology, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta, Indonesia 55281 3Center for Environmental Studies, Universitas Gadjah Mada, Daerah Istimewa Yogyakarta)



Article Info

Publish Date
28 Sep 2026

Abstract

Prolonged anthropogenic disturbance contributes to the degradation of Merdada Lake. Tourism development, intensive water extraction, fertilizer and pesticide application, and the conversion of land into agricultural areas have accelerated soil erosion, sediment accumulation, nutrient loading, and siltation, which ultimately reduce water quality and influence zooplankton communities. This study assessed the suitability of zooplankton as a bioindicator by examining community composition, abundance, daily variation, ecological indices, and key environmental constraints as indicators of trophic conditions. Sampling was carried out randomly in May 2021 at five observation sites with three replicates, conducted during nighttime (7:00 PM), early morning (5:00 AM), and morning (9:00 AM). The zooplankton community consisted of several functional groups, including Cladocerans, Copepods, Nauplius, Protozoa, and Rotifers. Abundance ranged from 5.51 to 22.47 individuals per liter, with Rotifers, particularly Philodina sp., being the most dominant group. Peak abundance was recorded at night, reflecting diel movement patterns associated with vertical migration and food availability. Ecological index analysis revealed poor-moderate diversity (H’ = 1.76–1.90), moderate -high evenness (E = 0.72–0.80), and high dominance (C = 0.79–0.82), which indicates an unstable community structure and ecological. Variations in zooplankton structure and daily dynamics were strongly associated with light intensity, nitrate concentration, dissolved oxygen, and alkalinity. Overall, the findings demonstrate that zooplankton communities are sensitive to environmental changes and can serve as effective bioindicators of water quality in Merdada Lake. Overall, zooplankton communities are responsive to water quality conditions in Merdada Lake.

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Journal Info

Abbrev

bioeksperimen

Publisher

Subject

Biochemistry, Genetics & Molecular Biology

Description

Aim Bioeksperimen: Jurnal Penelitian Biologi is a peer-reviewed, open-access scientific journal dedicated to advancing knowledge across a broad spectrum of biological sciences through the publication of high-quality original research articles. The journal promotes rigorous experimental and ...