BIODIVERSITAS ISSN: 1412-033X Volume 23, Number 11, November 2022 E-ISSN: 2085-4722 Pages: 5862-5868 DOI: 10.13057/biodiv/d231140 Variabilities of the carbon storage of mangroves in Gili Meno Lake, North Lombok District, Indonesia SITTI HILYANA 1, , FIRMAN ALI RAHMAN 2 1 Departement of Marine Science, Faculty of Agriculture, Universitas Mataram. Jl. Majapahit No.62, Gomong, Selaparang, Mataram 83125, West Nusa Tenggara, Indonesia. Tel./fax.: +62-370-633007,  email: sittihilyana@unram.ac.id 2 Department of Biology Education, Faculty of Education and Teacher Training, Universitas Islam Negeri Mataram. Jl. Pendidikan No. 35, Mataram 83127, West Nusa Tenggara, Indonesia Manuscript received: 5 September 2022. Revision accepted: 10 November 2022. Abstract. Hilyana S, Rahman FA. 2022. Variabilities of the carbon storage of mangroves in Gili Meno Lake, North Lombok District, Indonesia. Biodiversitas 23: 5862-5868. Mangrove is one of the coastal vegetation that can act as carbon mitigation (carbon sink and carbon storage). This study aims to determine the potential for carbon sinks and storage in the leaves and roots of each type of mangrove found in Gili Meno lake, North Lombok, Indonesia. The research includes the identification of species and sampling (leaves and roots) of mangroves in the research quadrant. The organic carbon content of mangrove leaves and roots was tested using the Wakley and Black method. The results showed that there were 5 (five) types of mangroves in Gili Meno lake, namely: Avicennia marina, Lumnitzera racemosa, Bruguiera cylindrica, Rhizophora apiculata, and Excoecaria agallocha. The highest leaf tissue carbon content value was R. apiculata at 45.85%C or equivalent to 3.19 g.C, while in roots, A. marina was 50.06%C, equivalent to 4.49 g.C. In addition, the potential carbon stock in the leaves of the entire mangrove ecosystem in an area of 3 ha is 762.81 tons.C±199.257 and at the roots is 659.76 tons.C±394.848, while the largest potential carbon stock in leaf organs is the type of mangrove R. apiculata, which is 318.91 tons.C.ha -1 . and at the root is the type of mangrove A. marina, amounting to 448.54 tons.C.ha -1 . The estimated carbon dioxide uptake by the Gili Meno mangrove leaves is in the range of 130.36 g.CO2-168.27 g.CO2 or with an average of 154.34 g.CO2±14.376, while the species with the highest carbon dioxide absorption capacity is R. apiculata (268.27 g.CO2) and the lowest in the species of L. racemosa (130.36 g.CO2). Keywords: Carbon dioxide, carbon stores, mangroves INTRODUCTION Gili Meno is a small island in North Lombok District, West Nusa Tenggara (NTB) Province. Geographically, Gili Meno is located between Gili Trawangan and Gili Air. One of the characteristics of Gili Meno among small islands in general in NTB or Indonesia is the presence of a saltwater lake located in the middle of the island. Gili Meno saltwater lake has an area of 6.6 ha with a diversity of biota (flora and fauna) and unique physical and chemical characteristics of the lake waters. One of them is extreme salinity conditions with an average of 54.00±0.82 ppt (Rahman and Hadi 2021), this condition is different in general in Indonesian marine waters, namely in the range of 33-43 ppt by the salinity quality standard based on the Indonesian Minister of Environment Decree No. 51 of 2004. The uniqueness of extreme environmental parameters in the Gili Meno saltwater lake requires the biota that makes up the lake ecosystem to survive, one of which is the vegetation of various types of mangroves that grow around the lake with an area of ±3 ha. Mangrove vegetation that grows around the Gili Meno lake has various environmental services, namely as a buffer for the island ecosystem in its benefits environmental services such as carbon dioxide (CO2) absorption, disaster mitigation (abrasion, coastal waves, sea breeze barriers, and tsunamis), availability of clean air (O2), stability of coastal waters, habitat for biota, mangrove ecotourism and germplasm (Aksornkoae and Kato 2011; Mcleod et al. 2011; Pendleton et al. 2012; Giri et al. 2015; Nordhaus et al. 2019; Rahman et al. 2020; Sadono et al. 2020; Alimbon and Manseguiao 2021a). One of the important issues related to mangrove ecosystems is the study of mangrove ecology related to environmental services, namely the ability to absorb and store carbon below and above the soil surface (Estrada and Soares 2017; Taillardat et al. 2018; Widyastuti et al. 2018; Kusumaningtyas et al. 2019; Matatula et al. 2021). Various previous studies have proven that mangrove ecosystems have a greater carbon storage capacity than terrestrial forest and seagrass ecosystems, even though the world's mangrove forests only cover 0.2% of land vegetation cover (Hamilton and Casey 2016). Mangrove forest carbon storage can reach 6-8 tons.C.ha -1 .yr -1 compared to land forest carbon storage capacity of 1.8-2.7 tons.C.ha -1 .yr -1 and seagrass ecosystem with a storage capacity of 2-4 ton.C.ha -1 .yr -1 (Murray et al. 2011). In addition, according to Murdiyarso et al. (2015) that the total carbon potential of Indonesian mangrove forests is around 3.14 Pg.C or globally of 69 million tonnes of carbon (Worthington and Spalding 2018). Considering the importance of mangroves as a buffer ecosystem for the Gili Meno lake area, which has a role in