Effects of tourism-derived sewage on coral reefs: Isotopic assessments identify effective bioindicators. (November 2019)

• Record Type: Journal Article
• Authors: Lachs, Liam; Johari, Nur Arbaeen Mohd; Le, Dung Quang; Safuan, Che Din Mohd; Duprey, Nicolas N.; Tanaka, Kentaro; Hong, Tan Chun; Ory, Nicolas C.; Bachok, Zainudin; Baker, David M.; Kochzius, Marc; Shirai, Kotaro
• Is Part Of: Marine pollution bulletin. Volume 148(2019)
• Page Start: 85
• Page End: 96
• Publication Date: 2019-11
• Subjects: Nitrogen stable isotopes -- Nutrient enrichment -- Sewage bioindicators -- Tourism development -- Community structure -- Resilience; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2019.07.059
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Pulau Redang and Pulau Tioman have experienced huge tourism growth over the last two decades, but minimal sewage treatment may threaten the resilience of their coral reefs. This study uses stable isotope techniques to identify suitable bioindicators of sewage nutrients (δ 15 N) at these islands by measuring macroalgae ( Lobophora spp.), gastropods ( Drupella spp.), scleractinian coral ( Acropora spp.), and leather coral ( Sinularia spp.). At tourist hubs using seepage septic tank systems, enrichment of Acropora δ 15 N (Redang, +0.7‰) and Sinularia δ 15 N (Tioman, +0.4‰) compared to pristine background levels indicate enhanced sewage nutrient discharge. Carbon isotopes and survey data suggest that sedimentation did not confound these δ 15 N trends. Potential damaging effects of sewage discharge on the coral reef communities at both islands are highlighted by strong correlations between Acropora δ 15 N and regional variation in coral reef community structure, and exclusive occurrence of degraded reefs at regions of high sewage influence. Highlights: Stable isotope baseline for Acropora, Drupella and Sinularia in Redang and Tioman Elevated δ 15 N at tourist hubs of both islands indicate sewage nutrient enrichment Co-occurrence of elevated δ 15 N alongside degraded coral reefs Significant correlation between δ 15 N and regional variance in community structure Drupella spp. are likely to have non-acroporid feeding strategies