Comparison of seaweed communities in coastal waters with different heavy metals concentrations in Minahasa Peninsula, North Sulawesi, Indonesia

• Published in: Aquaculture, Aquarium, Conservation & Legislation Vol. 13; no. 4; pp. 1779 - 1794
• Main Authors: Tombokan, John L, Kepel, Rene C, Mantiri, Desy M H, Paulus, James J H, Lumingas, Lawrence J L
• Format: Journal Article
• Language: English
• Published: Cluj-Napoca Bioflux SRL 01.08.2020
• Subjects: Algae; Aquaculture; Biodiversity; Clustering; Coastal waters; Community structure; Dominance; Environmental protection; Fishing; Halimeda opuntia; Heavy metals; Identification; Marine aquaculture; Metal concentrations; Metals; Public health; Sampling techniques; Sea grasses; Seawater; Seaweeds; Sediments; Species composition; Species diversity; Species richness; Stations; Tourism; United States > US; Sulawesi; Indonesia
• ISSN: 1844-8143; 1844-9166

This study was conducted to compare the biodiversity and community structure (species composition, richness, diversity, evenness, dominance and clustering) of seaweeds found in coastal waters at different metal concentrations such as the presence of heavy metals due to small-scale mining activities in the upstream in North Minahasa Regency (Talawaan Bajo), fishing and mariculture activities (Kora-Kora) in Minahasa Regency, and marine tourism activities (Tanjung Merah) in Bitung City. The line transect method was used to identify and quantify the seaweeds abounding the three established stations divided into three transects each station, and each transect divided into ten quadrates. A total of 19 different species of seaweeds were identified in the study area belonging to the classes of Rhodophyceae (Rhodomelaceae, Lithophyllaceae, Galaxauraceae, Gracilariaceae, Cystocloniaceae families), Phaeophyceae (Dictyotaceae, Sargassaceae families) and Ulvophyceae (Ulvaceae, Halimedaceae, Cladophoraceae, Siphonocladaceae, Valoniaceae families). The most abundant seaweed species across the three stations is: Halimeda opuntia. The seaweed species identified also have different densities ranging from 0.10 to 12.20 per m2. Halimeda opuntia had the highest density, and Hypnea boergesenii, Boodlea composita, Dictyota dichotoma, Sargassum crassifolium, Amphiroa fragilissima, Galaxaura rugosa, Actinotrichia fragilis, Turbinaria ornata and Laurencia papillosa had lower densities. Species richness index, diversity index, evenness index and dominance index were calculated to determine the diversity of seaweeds along the study area. Station 2 obtained the highest species richness index and station 1 obtained the lowest species richness index. Station 3 recorded the highest diversity index and station 2 recorded the lowest diversity index. Evenness index was highest at station 1, while the lowest was at station 2. The dominance index was the highest at the station 2, while the lowest at the station 1. The three sampling stations are divided into 3 groups based on an abundance of 19 species of seaweeds. The three groups are Group I (TM1, TM2, TM3), Group II (KK1, KK2, KK3), and Group II (TB1, TB2, TB3). Apparently, the three station groups are related to the type of sediment and presence of seagrass but not due to metal concentrations.