DEPIK Mollusk Diversity in the Intertidal Zone of Menganti Beach
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Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan (2020) 10(1): 23-29 DEPIK Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan Journal homepage: www.jurnal.unsyiah.ac.id/depik Mollusk diversity in the intertidal zone of Menganti Beach, Kebumen, Central Java Steviana Amalia Ratih*, Meilisha Putri Pertiwi, Raden Teti Rostikawati Biology Education Study Program, Faculty of Teacher Training and Educational Science, Pakuan University, Bogor, Indonesia. ARTICLE INFO ABSTRACT Keywords: Limited information about Mollusks in Menganti Beach, Central Java has been a strong basis for researching its Mollusk diversity. This study aimed to determine the mollusks' diversity in Menganti Beach, Kebumen. The research was Diversity conducted from April to May 2020, using a survey method and purposive sampling technique. Sampling was Intertidal Zones undertaken at three stations with the belt transect method. The results revealed 37 species with 1767 individuals Coastal from the Class Bivalvia, Gastropods, and Polyplacophora. Based on the diversity index value H '= 3.3, station 1 with the rocky sand substrate is the best for mollusks' habitat. The H' value at station 1 shows the highest diversity that the base substrate is dominated by sand and rocks, which are very supportive of mollusks. It is supported by the evenness value (E), which indicates evenly distributed species, and dominance value (D), which does not indicate a species' dominance. The a-biotic parameters at the three stations obtained an average morning temperature of 29 oC and 30 oC in the afternoon, pH of 7, and a salinity of 30 ‰ so that these values DOI: 10.13170/depik.10.1.18673 support the Mollusk habitat at Menganti Beach, Kebumen. Introduction members, the Bivalves and the Gastropods. Both The Indonesian oceans are vital in the world have various body shapes and shell sizes (Fontoura- ecosystem that stores the potential of natural da-Silva et al., 2013). resources and high diversity. One of the popular Mollusks are sensitive to environmental changes. regions with its unique and enchanting marine They have an ecological role as bioindicators, wealth in southern Central Java is Menganti Beach, especially in aquatic ecosystems. Besides, mollusks Kebumen. Menganti Beach's habitat characteristics can accumulate heavy metals without dying are suitable for the life of mollusk. Preliminary (Wahyuni et al., 2017). Mollusks also acts as a observations on the coast of Menganti Beach found connector in a food chain as detritus (organic a group of animals with distinctive soft-body. These matter). Detritus is mainly sourced from leaves, animals are known as the Mollusca group, soft- mangrove branches that fall and rot, which then bodied triploblastic coelomate animals. mollusks use as an initial decomposer (Katukdoan et After Arthropods, mollusks are the second most al., 2018). diverse phylum. There are around 93,000 living Mollusks, which are the primary calcareous species and about 70,000 known fossils. There are organisms with extensive fossil records, have eight Mollusks classes reported globally: provided important information about past climatic Caudofoveata, Aplacophora, Monoplacophora, events and ocean changes, thereby increasing Polyplacophora, Scaphopoda, Cephalopods, predictions of future changes (Fortunato, 2015). Gastropods, and Bivalves. Among these classes, Mollusks have been used for various commodities only the Gastropods and Bivalves can be found in such as food products, accessories, and raw freshwater (Brusca and Brusca, 2003). materials for medicines (Islami et al., 2018). The phylum Mollusca has two of the largest, This research focuses on coastal areas, namely most distributed, and scientifically famous the intertidal zone. Nugroho (2012) stated that the * Corresponding author. Email address: [email protected] Received 19 November 2020; Received in revised from 8 February 2021; Accepted 15 February 2021 Available online 24 April 2021 p-ISSN 2089-7790; e-ISSN 2502-6194 This is an open access article under the CC - BY 4.0 license (https://creativecommons.org/licenses/by/4.0/) Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan RatihA et al. ( 2021 ) Volume 10, Number 1, Page 23-29 intertidal zone has high nutrient wealth and is rich with in-situ observation to the observation location in oxygen. This area also receives sufficient sunlight, and hand sorting for direct sampling in their habitat. so it is very suitable for an invertebrate breed like The research location used three observation echinoderms and mollusks (Triacha et al., 2021). stations in the coastal area of Menganti Beach The results of observations, data, and (intertidal zone). information regarding the mollusks diversity in the The station is determined based on the situation intertidal zone of Menganti Beach, Kebumen, and environmental conditions in the field. They are Central Java have not revealed the issue assuredly. the state of vegetation, the dominating substrate, The limited information about mollusks in and the surrounding activities. Each station has Menganti Beach is the basis for conducting research varied substrate characteristics: station one with a related to the diversity of mollusks to facilitate the rocky sand substrate; station two with a coral calculation of its species diversity. Based on the substrate; and station three with a seagrass bed as a description above, it is necessary to research the substrate (Figure 1). mollusks' diversity in the intertidal zone of The technique of collecting data (Sampling) Menganti Beach, Kebumen, Central Java. Systematic sampling of mollusks using a purposive sampling technique. It used the belt Materials and Methods transect method presented in Figure 2. According to Location and Time Johan (2003), the belt transect method aims to The study was conducted from April to May describe the population of an organism, the number 2020 in the intertidal zone of Menganti Beach, of individuals and colonies, and the number of Karangduwur Village, Ayah Subdistrict, Kebumen species and distribution. One of the organisms' Regency, Central Java Province. Karangduwur characteristics is the varied sizes with specific Village is an area of 415.2320 hectares, in which maximum sizes, like invertebrates. Menganti Beach is about 40 km from the center of The belt transect design applied was spread over Kebumen. The coordinates of Menganti Beach are 100 meters in a perpendicular position from the at 07°46'12.7"S 109°24'46.7"E. lowest tide limit to the shoreline in the intertidal zone of Menganti Beach. The transects were spread over three stations with different substrate types. Each station consisted of five plots in the shape of a 5 x 5 meters-square, separated by 15 meters between each. The determination of transects relates to the conditions of the location and substrate in the field. Figure 1. Research location at Menganti Beach, Kebumen. Population and sample Population in this study is all Phylum Mollusca species in the intertidal zone of Menganti Beach, Kebumen. The sample in this study is the Phylum Mollusca species found at each research station Figure 2. The design of belt transects in sampling point. location. Methods of data collection This research used a survey method conducted Data collection procedure with a descriptive exploratory approach that The sampling process was carried out for two describes the diversity of mollusks. Data collection days at low tide, in the morning starting at around 24 Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan RatihA et al. ( 2021 ) Volume 10, Number 1, Page 23-29 06.00 WIB and in the afternoon at 16.00 WIB, The Dominance Index is analyzed using the followed by counting the number of individuals Dominance of Simpson formula (Magurran, 1988): found in each plot. with Abiotic parameter data were taken at each research station, including temperature, pH, and Information: salinity. According to Odum (1993), the D = dominance index measurement of abiotic parameters aims to ni = number of individuals per species determine the Physico-chemical conditions of N = total number of individuals aquatic ecosystems related to environmental conditions that support aquatic-biota. Results Making preserves is done outside the field to There were 37 species of mollusks obtained with facilitate the process of identifying species. It started 1767 individuals, including the classes of Bivalve, by storing specimens immersed in 70% alcohol Gastropod, and Polyplacophora. The results of solution in closed jars (Melay et al., 2015). The jars observations of mollusks species are presented in were labeled with a description containing the Table 1. sample number, name of the collector, date of Based on the data obtained from Mollusks, collection, location, habitat, and a note for the calculations were made to find the values of sample color. diversity index (H '), evenness index (E), and The samples obtained were identified using dominance index (D). The index values found at relevant books and references as follows: the station 1 (rocky sand), station 2 (coral), and station 3 identification of Bivalve and Gastropod classes (seagrass beds) can be seen in Table 2. The average referring to "The Living Marine Resources of the Western results of measuring abiotic parameters at the study Central Pacific. Volume 1", a book by Carpenter and location for two days in the morning and afternoon, Niem (1998) and "The Living Marine Resources of the can be seen in Table 3. Eastern Central Atlantic. Volume 2." by Carpenter and Nicoletta (2016);