Spatial variation in the persistence of algal blooms: Evidence from the Nakdong River

Tae-Hyuna Kim

doi:10.3741/JKWRA.2026.59.10.1161

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2026 Vol.59, Issue 10 Next Page

Spatial variation in the persistence of algal blooms: Evidence from the Nakdong River 낙동강 주요 구간별 녹조 지속성 분석

31 October 2026. pp. 1161-1169

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Abstract

This study investigates how harmful algal blooms persist over time in the upstream, midstream, and downstream sections of the Nakdong River. Bloom severity depends not only on how often blooms occur, but also on how long elevated bloom conditions remain after an increase. To examine this dimension, chlorophyll-a and harmful cyanobacteria cell counts are used as bloom indicators, and ARMAX models are applied to weekly time-series data constructed from algal monitoring observations collected between April and October. The estimated half-lives of chlorophyll-a are 0.71 weeks upstream, 0.70 weeks midstream, and 0.77 weeks downstream. The corresponding half-lives for harmful cyanobacteria cell counts are 1.00, 1.25, and 1.75 weeks. Overall, persistence becomes stronger toward the downstream section, and this pattern is more pronounced for harmful cyanobacteria cell counts than for chlorophyll-a. These findings suggest that bloom management should account for reach-specific differences in persistence, with particular attention to earlier and more preventive intervention in downstream areas.

Keywords

Algal blooms

Persistence

Nakdong River

ARMAX

본 연구는 낙동강 수계의 상류, 중류, 하류를 대상으로 녹조의 단기 동태적 지속성을 비교·분석한다. 녹조의 심각성은 발생 여부뿐 아니라 발생 이후 녹조 상태가 얼마나 지속 및 감쇠하는가에 의해서도 결정된다. 이에 본 연구는 클로로필-a와 유해남조류 세포수를 녹조 지표로 설정하고, 4월부터 10월까지의 조류 모니터링 자료를 주간 단위로 재구성한 뒤 ARMAX 모형을 적용하였다. 분석 결과, 클로로필-a 발생의 반감기는 상류 0.71주, 중류 0.70주, 하류 0.77주로 나타났고, 유해남조류 세포수 발생의 반감기는 상류 1.00주, 중류 1.25주, 하류 1.75주로 추정되었다. 이는 녹조 발생의 감쇠 속도와 지속성이 하천 위치와 지표에 따라 다르며, 특히 하류에서 유해남조류 세포수의 지속성이 더 크게 나타남을 보여준다. 이러한 결과는 녹조 관리가 평균적인 발생 수준의 저감에 그치지 않고, 구간별 지속성 구조를 반영한 예방 및 초기 대응 중심의 맞춤형 전략으로 설계될 필요가 있음을 시사한다.

키워드

녹조

동태적 지속성

낙동강

ARMAX

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Information

Publisher :KOREA WATER RESOURECES ASSOCIATION
Publisher(Ko) :한국수자원학회
Journal Title :Journal of Korea Water Resources Association
Journal Title(Ko) :한국수자원학회 논문집
Volume : 59
No :10
Pages :1161-1169
Received Date : 2026-04-14
Revised Date : 2026-05-18
Accepted Date : 2026-05-30
DOI :https://doi.org/10.3741/JKWRA.2026.59.10.1161

Journal of Korea Water Resources Association ISSN:2799-8746(Print) 2799-8754(Online) 한국수자원학회 논문집

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