ANALYSIS OF NUTRIENTS DISTRIBUTION AND ABUNDANCE ON THE WATERS AROUND MOUNT ANAK KRAKATAU

• Main Author: Imanda Yusuf - NIM: 12914011 , Mutiara
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29428
• Institution: Institut Teknologi Bandung

<p align="justify">The aimed of this study to determine nutrients distribution, abundance and trophic state on the waters around Mount Anak Krakatau. Water samples is taken at 17 stations in 11-12 September 2017 and 22 stations in 17-18 April 2018. Samples of water were tested to determine the concentration of: nitrate, nitrite, ammonia, phosphate, silica, potassium, iron, manganese, magnesium, and calcium which tested using different method. Spectrophotometry was used for nitrate, nitrite, ammonia, phospate, and silica. Titration method for calcium and magnesium, and Atomic Absorption Spectrophotometry for iron, manganese, and potassium. The result show that total nitrogen (0,247 – 0,593 mg N/l) and phosphate (0,022-0,055 mg P-PO4/l) had higher concentration than natural seawater. Both nitrogen and phosphate tend to have high concentration in stations close to the shore and nutrients move to southwest due to the southwestward flow in September. Whereas silicate (0-0.164 mg/l) has a higher concentration near bottom on 11-12 September 2017 and on the surface on 17-18 April 2018. Iron and manganese actually have very high concentration compared to marine waters in general (0.05-0.2 mg/l, (Boyd, 1988)) . The high concentration of iron (ranging from 0.6 mg/L to 4.4 mg/l) is closely related to the wet deposition process of volcanic ash which affected by high precipitation at April 2018. Then for potassium, calcium, and magnesium have almost uniform values at each station because it is a conservative element. and it has ratio with salinity that commonly found in other marine waters. From the values of total nitrogen concentration, found that the trophic status of the waters around Gunung Anak Krakatau is classified as eutrophic on 11-12 September 2017 and mesotrophic on 17-18 April 2018, and based on phosphate concentration classified as eutrophic on 11-12 September 2017 and hyper-eutrophic on 17-18 April 2018. <p align="justify">