Gastropods is an important organism that commonly found inhabiting the rocky intertidal area. Distribution pattern of this species is influenced by various factors such as population history, microhabitat, predation and a complex interactions between oceanographic dynamics and ecological features. This study aims to compare the temporal distribution pattern of gastropods at two different rocky intertidal area. This research was conducted at the rocky intertidal area of Amban and Nuni, North Manokwari District, West Papua. Data collection was performed during the daylight and night in April and June 2012 using systematic sampling method. The results showed that both physical and chemical factors are suite for supporting gastropods life. Furthermore, these factors seem to have an impact on gastropod zoning patterns observed in the study area. The similarity index values ​​indicate that the similarity of gastropod species between the two locations is low, which means that the species of gastropods found in each location is quite different. The community structure of gastropod at the study area is stable. In addition, we found that the gastropods diversity were higher during the night than the daylight because gastropods are classified as a nocturnal animals. Key Words: Gastropod; Rocky Intertidal; Community Structure; Nocturnal

The content of secondary metabolite compounds in marine plants, especially mangrove has a certain bioactivity. Therefore, this study was aims to determine the content of secondary metabolites in the mangrove leaf extract of Rhizophora apiculata and Rhizophora mucronata. This study was conducted on January-April 2020. Sampling locations were carried out in the Mangrove Conservation Area of Tuban Village, Bali. In this study, samples were collected in the form of old leaves. The samples were taken in three sites and in each sites, 500 gr of leaves were collected randomly for each species. Therefore, in total we have 1.5 kg of leaves for each species. Samples are then extracted and tested to determine the content of secondary metabolites. The results showed the content of secondary metabolites in the leaves of R. apiculata mangrove were phenols, alkaloids, flavonoids, tannins, saponins, steroids while R. mucronata contained phenols, flavonoids, tannins, saponins, terpenoids.

The seagrass ecosystem has great potential in absorbing of CO2 concentration in atmosphere, results of the process photosynthesis will be stored in form of biomass during seagrass still alive. The research purpose was to know carbon storage from the seagrass ecosystem at the top substrate (leaves) and bottom substrates (rhizome and roots) in Nusa Lembongan coastal area, Bali. The research location is divided into three stations with 27 points. Carbon stock was analyzed by using invasion method consisting of calculating the value of ash content, organic matter content and carbon content. The results found three seagrass species in the Nusa Lembongan coastal area: Thalassia hemprichii, Cymodocea rotundata and Enhalus acoroides. The most dominant spesies is the Thalassia hemprichii. The carbon stored at the top substrate (leaf) is 21.08 gC/m2 and the bottom substrates (rhizome and root) are 52.67 gC/m2. The total estimated carbon deposits in the Nusa Lembongan coastal area is 65.98 tonnes with carbon deposits in the bottom substrate are larger than the top substrate, which is 71% or 47.12 tons on the bottom substrate while 29% or 18.86 tons on the top substrate.

Tanjung Benoa is a waters in Bali that is influenced by the monsoon pattern system which has a different circulation pattern of water masses and varies between seasons. The difference in mass of water resulted in changes in the condition of the waters that affect the high and low productivity of the waters and abundance of mollusks in the waters of Tanjung Benoa. Mollusks have an important role for the aquatic environment, namely as a bio-indicator of environmental health and water quality. This study aims to determine the structure of the molluscs community and determine the environmental factors that influence the western season and the transition season I. Sampling is done in January 2019 (west season) and in March 2019 (Transition I). The results of the analysis showed a decrease in diversity and uniformity occurred in the fourth week (west season) and the seventh week (transition season I) with the category of moderate species diversity and medium type uniformity. The low value of uniformity and diversity in the western season is influenced by increasing pH values and decreasing waters nitrate values. When compared with the western season, in the transition season I the increase in temperature and a decrease in phosphate value occur in the seventh week. this result was obtained using principal component analysis (PCA) that used the environmental parameter index and the value of diversity and uniformity of mollusks. However, this value is still in the medium category. So it can be seen in the western season and the transition season. The state of mollusks in Tanjung Benoa waters is stable and can adapt to seasonal changes and environmental conditions.

The demands of marine organisms for the aquarium trade are remain high and seems continue to increase. Consequently, many of marine organisms has been spread out from its natural habitat as in the case of endemic Banggai cardinalfish, (Pterapogon kauderni). That has invaded “new” habitat since it being trade in 1995. In recent years, a small populations of P. kauderni is known to be exist in a narrow bay near the Gilimanuk harbor, Bali. An underwater visual fish census survey was conducted on June 2018 to estimate the habitat types and densities of P. kauderni.  Additionally, 23 specimens of P. kauderni were collected randomly in order to assess biological parameters such as the length-weight relationship. We successfully recorded 30 groups of P. kauderni that inhabit a shallow areas with a depth range between 0.5m to 2m. Of these, more than 90% of the groups were found to be associated with sea urchin (Diadema sp.) while the rest were found to live together with branching coral (Acropora sp.) and branching sponge (Ptylocaulis sp.). Total number of fish observed during the survey were 381 individuals. The fish density is 0.76 individu.m-2. Length-weight relationship showed that P. kauderni exhibit is negative allometry (b<3) which mean that the increase in length is faster than the weight gain. Interestingly, from the 23 specimens collected, none of these were sexually mature (SL<41 mm) which may indicated that the population of P. kauderni in Bali are under serious threats of exploitation.