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Analysis of the seawater CO 2 system in the barrier reef‐lagoon system of Palau using total alkalinity‐dissolved inorganic carbon diagrams
Author(s) -
Watanabe Atsushi,
Kayanne Hajime,
Hata Hiroshi,
Kudo Setsuko,
Nozaki Ken,
Kato Ken,
Negishi Akira,
Ikeda Yutaka,
Yamano Hiroya
Publication year - 2006
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2006.51.4.1614
Subject(s) - alkalinity , seawater , reef , coral reef , dissolved organic carbon , oceanography , bay , carbon dioxide , environmental science , water column , total inorganic carbon , geology , ecology , chemistry , biology , organic chemistry
We studied the seawater carbon dioxide (CO 2 ) system in the Palau coral reef by measuring total alkalinity (TA) and total dissolved inorganic carbon (DIC). Variation in the CO 2 system on the reef flat and in the lagoon was analyzed by TA‐DIC diagrams, taking into accounts the differing residence times of seawater. CO 2 in the offshore water was relatively stable in space and time, but on the reef flat it was subject to rapid (about 3 h) and substantial changes due to photosynthesis and calcification during the day and due to respiration and calcification at night. Water flowed into the lagoon where decomposition of organic matter and continuing calcification occurred over relatively long residence times (~30 d). Despite the spatial and temporal variations, the center of the lagoon had relatively constant TA and DIC values similar to the mean values for the entire lagoon. A long‐term 30–40% decrease in reef productivity and calcification has occurred over the last decade, primarily a result of degradation of the reef environment following a major coral reef bleaching event in 1998. This is reflected in decreases in the differences in TA and DIC between offshore lagoon waters and those in center of the lagoon.