High-resolution underway measurements of phytoplankton photosynthesis and abundance as an innovative addition to water quality monitoring programs
<p>Marine waters can be highly heterogeneous both on a spatial and temporal scale, yet monitoring programs currently rely primarily on low-resolution methods. This potentially leads to undersampling. This study explores the potential of two high-resolution methods for monitoring phytoplankton...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-09-01
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| Series: | Ocean Science |
| Online Access: | https://www.ocean-sci.net/15/1267/2019/os-15-1267-2019.pdf |
| Summary: | <p>Marine waters can be highly heterogeneous both on a spatial and
temporal scale, yet monitoring programs currently rely primarily on
low-resolution methods. This potentially leads to undersampling. This study
explores the potential of two high-resolution methods for monitoring
phytoplankton dynamics: fast repetition rate fluorometry for information on
phytoplankton photosynthesis and productivity and automated scanning
flow cytometry for information on phytoplankton abundance and community
composition. These methods were tested in combination with an underway
Ferrybox system during four cruises on the Dutch North Sea in April, May,
June, and August 2017. The high-resolution methods were able to visualize
both the spatial and temporal variability of the phytoplankton community in the
Dutch North Sea. Spectral cluster analysis was applied to objectively
interpret the multitude of parameters and visualize potential spatial
patterns. This resulted in the identification of biogeographic regions with
distinct phytoplankton communities, which varied per cruise. Our results
clearly show that the sampling based on fixed stations does not give a good
representation of the spatial patterns, showing the added value of underway
high-resolution measurements. To fully exploit the potential of the tested
high-resolution measurement setup, methodological constraints need further
research. Among these constraints are accounting for the diurnal cycle in
photophysiological parameters concurrent to the spatial variation, better
predictions of the electron requirement for carbon fixation to estimate
gross primary productivity, and the identification of more flow cytometer
clusters with informative value. Nevertheless, the richness of additional
information provided by high-resolution methods can improve existing
low-resolution monitoring programs towards a more precise and ecosystemic
ecological assessment of the phytoplankton community and productivity.</p> |
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| ISSN: | 1812-0784 1812-0792 |