Seagrass is one of the most important ecosystems in coastal areas. Seagrass beds can absorb carbon of 1.15 tons/ha, with a carbon content below the substrate of 0.88 tons/ha (76.3%), higher than the carbon above the substrate, which is only 0.27 tons/ha (23, 7%). Research on carbon absorption in seagrass is still relatively carried out, so it is necessary to research the potential for carbon absorption in seagrass types Enhalus acoroides and Thalassia hemprichii in Morotai waters. The research will be carried out from September to December 2021, starting with seagrass sampling in three sub-districts (South Morotai, East Morotai, and South West Morotai Districts). The types of seagrass used were Enhalus acoroides and Thalassia hemprichii. Biomass sample analysis was carried out at the Basic Laboratory of the Faculty of Fisheries and Marine Sciences, Pacific Morotai University. Carbon analysis on seagrass was carried out at the Chemical Oceanography Laboratory of the Faculty of Marine and Fisheries Sciences, Hasanudin University Makassar. The seagrass sampling method used the quadratic transect method and sample analysis using the method Loss On Ignition (LOI). The results showed that Thalassia hemprichii has the highest carbon content in the roots, with a value of 38.94 gC/m2 to 49.48 gC/m2. In contrast, Enhalus acoroides has the highest carbon content in the roots with a carbon value of 30.77 gC/m2 to 37.86 gC/m2.

Shoreline change is a process that occurs dynamically and changes in sea bathymetry. The process of adjusting the coastline is continuously carried out for a natural balance against various impacts that can affect changes in the coastline. The process of changing the coastline can occur naturally and is anthropogenic. Based on this description, it is necessary to study/research changes in the coastline seen from oceanographic factors in the form of currents on Tabailenge Island, North Morotai District, Morotai Island Regency. This research was conducted in November 2022 in the waters of Tabailenge Island, South Morotai District, Morotai Island Regency. Analysis was conducted using field data (primary) and Google Earth software image data (secondary). Analysis was carried out using image data from different years (2009, 2011, 2016, 2019, and 2021). The research phase begins with preparing photo image data that will be analyzed for changes in the coastline using satellite imagery from the Google Earth application for the observation periods of 2009, 2011, 2016, 2019, and 2021. Image data use the JPEG format for different months of observation depending on availability. Cloud-free data contained in Google Earth. Based on data from image interpretation in 2009, 2011, 2016, 2019, and 2021, digitization has been carried out to show that there has been a change in the coastline from year to year. Observation of image data for a period of ± 10 years shows that changes in the coastline occur due to the influence of oceanographic parameters such as currents.