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Review

Review of Methods for Measuring the Particle Size of Flocs in Marine Cohesive Suspended Sediments

해양 점착성 부유퇴적물 플록 특성 규명을 위한 입자 크기 측정기술 리뷰

JUN YOUNG SEO1
,
SUN MIN CHOI2
,
SU IN KIM3
,
HO KYUNG HA4*
서 준영1
,
최 선민2
,
김 수인3
,
하 호경4*
1Professor, Department of Oceanography, Chonnam National University, Gwangju 61186, Korea
2Researcher, Korea Institute of Ocean Science and Technology, Geoje 53201, Korea
3Graduate Student, Department of Ocean Sciences, Inha University, Incheon 22212, Korea
4Professor, Department of Ocean Sciences, Inha University, Incheon 22212, Korea
1전남대학교 지구환경과학부 해양환경전공 교수
2한국해양과학기술원 남해연구소 선임연구원
3인하대학교 해양과학과 대학원생
4인하대학교 해양과학과 교수
*Corresponding Author
28 February 2026. pp. 14-30
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Abstract

Flocs are cohesive aggregates of fine-grained suspended sediments formed by electrochemical interactions and physical collisions among primary particles in marine environments. The porous structure of these flocs leads to significant spatiotemporal variability, making flocs important for various marine processes (e.g., particle settling, resuspension, pollutant transport, and biogeochemical cycling). The properties of floc vary with particle composition, organic matter content, morphology, effective density, and settling behavior. Moreover, the formation and behavior of flocs are controlled by a combination of factors including particle size, composition, organic content, morphology, effective density, and settling velocity. In addition, flocs are strongly subjected to the suspended sediment concentration and turbulence (physical factors), salinity and ionic composition (chemical factors), and binding effects driven by microorganisms and extracellular polymeric substances (biological factors). These complex interactions make quantitative characterization of flocs difficult and hinder the use of a single observational method. This study provides a comprehensive review of the principles and applications of instruments used to characterize flocs in marine settings. It highlights techniques such as acoustic sensors, laser scattering, holography, image-based methods, and X-ray or laser diffraction. In particular, this review examines specific instruments including the Acoustic Doppler Current Profiler (ADCP), LISST-Holo, floc cameras, SediGraph, and Mastersizer. The analysis focuses on differences in quantification capabilities, spatiotemporal resolution, and interpretive scope among these instruments. The comparison exhibits that no single instrument can capture the full complexity of floc behavior. Thus, a robust assessment of floc dynamics requires the integration of complementary measurements from multiple sensors. This synthesis serves as a practical reference for improving the understanding of floc-mediated sediment dynamics and refining models of sediment transport and biogeochemical processes in marine environments.

Keywords
Cohesive sediment
Flocculation
Floc
Particle size distribution
Particle-sizing instruments

해양환경에서 형성되는 점착성 퇴적물의 응집체인 플록(floc)은 일차입자 간의 전기화학적 상호작용과 물리적 충돌을 통해 형성되는 다공성 구조의 응집체로, 시·공간적으로 매우 높은 불균질성을 보인다. 이러한 플록은 부유물질의 침강과 재부유, 오염물질 및 유기물의 이동, 생지화학적 순환 등 다양한 해양 프로세스에 중요한 영향을 미친다. 플록의 형성과 거동은 입도, 조성, 유기물 함량, 형상, 유효밀도, 침강속도와 같은 특성뿐만 아니라, 수층 내 부유퇴적물농도와 난류 조건(물리적 요인), 염분 및 이온 조성(화학적 요인), 그리고 미생물 및 세포외고분자물질에 의한 결합 효과(생물학적 요인)에 의해 복합적으로 조절된다. 이로 인해 플록의 특성은 환경 조건에 따라 크게 변화하며, 이를 정량적으로 파악하는데 상당한 관측적 한계가 존재한다. 본 연구에서는 해양환경에서 플록 특성을 규명하기 위해 활용되는 대표적인 관측장비(음향, 광산란, 홀로그램, 이미지, X선‧레이저 회절)의 원리와 적용 범위를 체계적으로 정리하고, 각 장비가 제공하는 정량 정보의 해석 가능성과 한계점을 비교·검토하였다. 특히, ADCP, LISST-Holo, 플록카메라, SediGraph, Mastersizer를 중심으로, 플록의 크기, 형상, 유효밀도 및 침강속도를 해석하는데 있어 장비별 정량성, 시·공간 해상도 및 해석 가능 범위를 비교하였다. 이러한 비교·분석을 바탕으로, 시·공간적으로 변동성이 큰 플록의 복합적 거동을 신뢰성 있게 평가하기 위해서는 단일 장비에 의존하기보다 각 장비의 장점을 상호보완적으로 결합한 다중 센서 기반 통합 관측 전략이 필수적임을 제시하였다. 본 연구는 향후 플록 기반 퇴적물 거동 예측과 해양 퇴적물 거동 모델의 정밀화를 위한 기초자료로 활용될 수 있다.

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Information
  • Publisher :The Korean Society of Oceanography
  • Publisher(Ko) :한국해양학회
  • Journal Title :The Sea Journal of the Korean Society of Oceanography
  • Journal Title(Ko) :한국해양학회지 바다
  • Volume : 31
  • No :1
  • Pages :14-30
  • Received Date : 2025-11-24
  • Revised Date : 2026-01-19
  • Accepted Date : 2026-01-30
  • DOI :https://doi.org/10.7850/jkso.2026.31.1.014
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