Changes in pH, temperature, and salinity in seawater can indicate the occurrence of ocean acidification. The purpose of this research was to study changes in acidity that occur in Ohoililir waters, Southeast Maluku, which is part of the Banda Sea. This research was conducted in March 2019 as a study of the prefix of oceanic equities in the Southeast Maluku region which is part of the Banda Sea which is currently one of the priority researches in Indonesia, and sampling at 10 points. The results obtained were pH average of 8.69, temperature average of 29.74°C, and salinity of 33.23. The correlation between pH and temperature is -0.097 and the correlation between pH and salinity is in the range of -0.054 which indicates a very weak relationship between pH and temperature and salinity. Besides, pH has a negative correlation to temperature and salinity. This shows the need for further research on the relationship between these three or more parameters to see the effect on the ocean.

Ekosistem lamun merupakan salah satu ekosistem penting di laut, disamping terumbu karang dan mangrove sebagai pendukung kehidupan biota. Ekosistem lamun memiliki fungsi ekologi diantaranya adalah sebagai habitat, tempat pemijahan, pengasuhan, pembesaran, dan mencari makanan dari berbagai biota. Berkembangnya kegiatan manusia di wilayah pesisir khususnya di perairan Teluk Ambon seperti kegiatan pariwisata, pemukiman, dan aktivitas lainnya memungkinkan adanya pengaruh terhadap ekosistem lamun, sehingga diduga mengalami perubahan fisik, kelimpahan, maupun sebarannya. Tujuan dari penelitian ini untuk mengetahui keanekaragaman jenis dan persentase tutupan, serta kualitas air di ekosistem lamun Teluk Ambon. Penelitian ini dilakukan pada bulan September 2019 di Teluk Ambon dengan 7 (tujuh) stasiun yaitu Tanjung Tiram, Halong, Galala, Lateri, Passo, Waiheru, dan Tawiri. Data diperoleh menggunakan teknik transek dengan mengadopsi protocol dari UNESCO pada ekositem lamun yang kontinu atau koleksi bebas pada vegetasi lamun yang sepenggal-sepenggal. Parameter kualitas air yang diukur meliputi parameter fisika (suhu dan salinitas) dan parameter kimia (pH, DO, nitrat, silikat dan fosfat. Suhu, salinitas, pH, dan Do diukur secara in situ dengan menggunakan Water Quality Checker (WQC) WTW 3430 Set F. Sampel air dibawa ke laboratorium kimia Pusat Penelitian Laut Dalam LIPI Ambon untuk analisa nitrat, silikat dan fosfat dengan menggunakan metode spektrofotometri. Hasil yang diperoleh terdapat enam jenis lamun yang ditemukan di Teluk Ambon yaitu Enhalus acoroides, Thalassia hemprichii, Halophila ovalis, Halophina minor, Cymonocea rotundata, dan Halodule pinifolia. Persentase tutupan lamun pada setiap stasiun Galala : E. acroides (34,41%), T. hemprichii (28,37%), H. ovalis (1,40 %) dan H. pinifolia (35.81%); Halong : E. acroides (29,42%), T. hemprichii (7,95%), H. ovalis (1,77 %), C. rotundata (10.58%) dan H. pinifolia (35.81%); Tj. Tiram : E. acroides (41.51%), T. hemprichii (52,72%), H. ovalis (0,61 %) dan H. pinifolia (5.16%); Lateri : E. acroides (76.25%) dan T. hemprichii (52,72%); Passo : H. minor (100%); Waiheru : E. acroides (100%); Tawiri  H. ovalis (46,45%) dan H. pinifolia (53.55%). Suhu perairan lebih rendah dari suhu optimum. Salinitas perairan dan DO masih dalam bakumutu yang diperolehkan. Berdasarkan nilai pH maka perairan Teluk Ambon tergolong perairan tidak produktif. Kadar fosfat dan nitrat lebih tinggi dari bakumutu berdasarkan KMNLH 2004.

Polycyclic Aromatic Hydrocarbon (PAHs) is a polycyclic aromatic organic compound that is toxic to humans and aquatic organisms. This research aims to determine the level of pollution of PAHs compounds in seawater at the estuary of Cimandiri River, Pelabuhan Ratu. This research was conducted in April 2017 by survey method. Seawater samples were taken using a water sampler at 15 research stations. The levels and types of PAHs compounds were determined using Gas Chromatography-Mass Spectrometer (GC-MS), and PAHs sources with individual ratios diagnose. The results showed that seawater in the Cimandiri River Estuary still relatively low from contamination of PAH compounds. The type of PAH in seawater at the estuary of the Cimandiri River is dominated by low molecular weight naphthalene compound. PAH contained in seawater at the estuary of the Cimandiri River possibly comes from various sources, likely oil spills, burning petroleum, and combustion of organic compounds. PAH content in seawater of Cimandiri River estuary relatively small and still within the criteria for marine organism life state by The State Ministry Office for Life Environment.

The influence of nature and human activities greatly affects the distribution and diversity of algae. This study was conducted to determine the species diversity, density, phosphate concentration, and algae utilization as a food material found on the island of Ambon. The sampling location was on Ambon’s island in three locations, i.e., Tantui, Hative Besar, and Allang. For 100 m, line transects were laid perpendicular to the shore at every station. For every of the transect line, four 50 cm×50 cm quadrat was placed randomly. There was 18 genus of seaweed. Of the 22 species, 11 species from Rhodophyta (50.0 %), 5 species from Phaeophyta (22.73%), and 6 were from the class of Chlorophyta (27.3%). The highest value density is village Hative Besar that is 1219.9 gr.m−2 is from the Chlorophyta group (Enteromorpha prolifera), Tantui is 986 gr/m2 from the Rhodophyta group (Gracilaria), and Allang that is 756.18 gr.m−2 from the Rhodophyta group (Acantophora). The maximum concentration in Allang is 0.19 mg.L−1, concentration in Hative Besar is 0.18 mg.L−1, while the minimum phosphate concentration is 0.15 mg.L−1 at the Tantui location. The types of algae that can be used as food sources include Gracilaria sp., Caulerpa sp., Sargassum sp, Gelidium sp., and Ulva sp.

Research of heavy metals content in sediments was carried out in April 2006 on the bottom sea of Buton, Kabaena, and Muna islands. This study was aimed to determine the content of heavy metals Cd, Cu, Ni, Pb, and Zn and to predict the quality of the sediments by employing indices analysis. Sediment samples were taken using a grab at 8 stations. Heavy metal content was analyzed using AAS. Three indices are exercised to analyze the metal content in the sediment, that are contamination factors, geoaccumulation index, and pollution load index. The computation of contamination factors showed an average value of less than 1, namely Pb= 0.236, Cd= 0.269, Cu= 0.048, Zn= 0.346, and Ni= 0.986. Meanwhile, the geoaccumulation index values were less than 1, the value for Pb= -3.836, Cd= -2.878, Cu= - 5.061, Zn= -2.430, and Ni= -1.002. The pollution load index value is 0.201. These values which were less than 1 implied low level of pollution in the area. Thus, according to the analysis, the sediments in these three waters are still natural and not polluted.