Reconciling Coulter Counter and laser diffraction particle size analysis for aquaculture monitoring

• Published in: Environmental monitoring and assessment 2024-07, Vol.196 (7), p.672, Article 672
• Main Authors: Milligan, T. G., Law, B. A., Zions, V., Hill, P. S., Hua, K., McKindsey, C. W., Lacoursière‐Roussel, A.
• Format: Article
• Language: English
• Subjects: Animals; Aquaculture; Atmospheric Protection/Air Quality Control/Air Pollution; Benthic environment; Benthos; Bottom sediments; Canada; Community composition; Coulter counters; Deposition; Diffraction; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental changes; Environmental Management; Environmental Monitoring - methods; Far fields; Geologic Sediments - chemistry; Grain size; Introduced species; Lasers; Monitoring; Monitoring/Environmental Analysis; Particle Size; Salmon; Sediment; Sedimentary environments; Sediments; Soil properties; Species composition
• ISSN: 0167-6369; 1573-2959; 1573-2959
• DOI: 10.1007/s10661-024-12786-w

The disaggregated inorganic grain size (DIGS) of bottom sediment analyzed with a Coulter Counter (CC) has been used to show that the fraction of sediment deposited in flocs (floc fraction) increased in both the near and far field after the introduction of open cage salmon aquaculture, altering benthic habitat and species composition. As a result, DIGS was identified as a potential indicator of regional environmental changes due to aquaculture. Laser diffraction is an attractive alternative to the CC because of its greater efficiency and larger size range. To determine if a laser diffraction instrument, Beckman-Coulter LS 13 320 (LS), could replace the CC within a Canadian national aquaculture monitoring program, the DIGS of 581 samples from five different regions in eastern Canada were analyzed with an LS and a CC. Results show that the LS could not be used to calculate floc fraction. Instead, % sortable silt and the volume % of inorganic particles