Variation of seawater properties on tidal-scale in the entrance of Padangbai Lombok Strait Indonesia

• Published in: IOP conference series. Earth and environmental science Vol. 429; no. 1; pp. 12016 - 12023
• Main Authors: Suteja, Y, Atmadipoera, A S, Natih, M N, Wattimena, M, Masoleh, V, Pranoto, Y, Adhyatma, D, Widiastuti, P, Deswanti, S R, Triwahyuni, A, Watari, H, Hastuti, A W, Mamun, A, Vladoiu, A, Chonnaniyah
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2020
• Subjects: Chlorophyll; Dissolved oxygen; Diurnal variations; pH effects; Seawater; Straits; Turbidity; Water masses; Indonesia
• ISSN: 1755-1307; 1755-1315
• DOI: 10.1088/1755-1315/429/1/012016

During Marine Science Summer Course 2017, a continuous 24-h conductivity-temperature-depth (CTD) "yoyo" measurement has been carried out at the entrance of Padangbai Lombok Strait to investigate seawater properties variations on semidiurnal tidal-scale which is dominant in the strait. The SBE CTD 19 plus is equipped with optional sensors such as pH, turbidity and chlorophyll-a derived-fluoro. During 24-h field observation, 15 CTD casts from sea surface to about 60 m depth have been acquired. It is shown that observed seawater properties fluctuate strongly four times a day, following semidiurnal-tide period with two flood-tide and two ebb-tide conditions. During flood-tide, water mass is derived from open strait with colder, saltier, denser and low dissolved oxygen characteristics. In contrast, during ebb-tide, local water mass is recirculated back from the inner bay to the open strait. It is interesting to note that fluctuation of chlorophyll-a indicates a diurnal signal. In addition, fluctuation of pH, turbidity and dissolved oxygen showed a weak semidiurnal signal.