A study of the coastal seawater in Yap Island and Ulithi Atoll, Federated States of Micronesia, 2001

In the coastal reefs of Yap Island and Ulithi Atoll, water analysis to determine the environmental conditions of marine plant flora was carried out during October 2001. Seawater was collected and analyzed at 37 stations; 12 in Yap and 25 in Ulithi Atoll. Water temperature, salinity, dissolved oxygen (DO), pH, nitrate-nitrogen, nitrite-nitrogen, ammonium-nitrogen, inorganic phosphate and silicate were analyzed. The average water temperature, salinity and DO for Yap were 29.5 degree C, 33.2 psu and 6.20 mg l super(-1), respectively. Whereas, those of Ulithi Atoll were 29.5 degree C, 33.5 psu and 6.90 mg l super(-1), respectively. The average dissolved inorganic nitrogen (DIN), dissolved inorganic phosphate (DIP) and N to P ratios were: 4.40 mu M, 0.27 mu M, 2.65 mu M and 26, respectively. Whereas, those of Ulithi Atoll were 5.26 mu M, 0.24 mu M, 2.70 mu M and 32, respectively. There were no significant differences in any factors between the two locations and the amount of dissolved nutrients of each locality showed characteristic low concentrations of tropic and subtropic southwestern Pacific waters.