日本地球惑星科学連合2019年大会

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[E] 口頭発表

セッション記号 A (大気水圏科学) » A-HW 水文・陸水・地下水学・水環境

[A-HW22] 流域の物質輸送と栄養塩循環-源流域から沿岸海域まで-

2019年5月29日(水) 15:30 〜 17:00 201B (2F)

コンビーナ:小林 政広(国立研究開発法人森林研究・整備機構 森林総合研究所)、吉川 省子(農業・食品産業技術総合研究機構 農業環境変動研究センター)、安元 純(琉球大学 農学部 地域農業工学科)、Adina Paytan(University of California Santa Cruz)、座長:奥田 昇(総合地球環境学研究所)

15:40 〜 16:00

[AHW22-01] Coral Skeleton δ15N as a Tracer of Historic Nutrient Loading to a Coral Reef in Maui, Hawaii

★Invited Papers

*Adina Paytan1 (1.University of California Santa Cruz)

キーワード:Nitrogen Isotopes, Corals, Submarine Groundwater Discharge

Excess nutrient loading to nearshore environments has been linked to declining water quality and ecosystem health. Macro-algal blooms, eutrophication, and reduction in coral cover have been observed in West Maui, Hawaii, and linked to nutrient inputs from coastal submarine groundwater seeps. Here, we present a forty-year record of nitrogen isotopes (δ15N) of intra-crystalline coral skeletal organic matter in three coral cores collected at this site and evaluate the record in terms of changes in nitrogen sources. Our results show a dramatic increase in coral δ15N values after 1995, corresponding with the implementation of biological nutrient removal at the nearby Lahaina Wastewater Reclamation Facility (LWRF). High δ15N values are known to be strongly indicative of denitrification and sewage effluent, corroborating a previously suggested link between local wastewater injection and degradation of the reef environment. This record demonstrates the power of coral skeletal δ15N as a tool for evaluating nutrient dynamics within coral reef environments.