Abstract
Increasing contributions of prymnesiophytes such as Phaeocystis pouchetii and Emiliania huxleyi to Barents Sea (BS) phytoplankton production have been suggested based on in situ observations of phytoplankton community composition, but the scattered and discontinuous nature of these records confounds simple inference of community change or its relationship to salient environmental variables. However, provided that meaningful assessments of phytoplankton community composition can be inferred based on their optical characteristics, ocean-colour records offer a potential means to develop a synthesis between sporadic in situ observations. Existing remote-sensing algorithms to retrieve phytoplankton functional types based on chlorophyll-a (chl-a) concentration or indices of pigment packaging may, however, fail to distinguish Phaeocystis from other blooms of phytoplankton with high pigment packaging, such as diatoms. We develop a novel algorithm to distinguish major phytoplankton functional types in the BS and apply it to the MODIS-Aqua ocean-colour record, to study changes in the composition of BS phytoplankton blooms in July, between 2002 and 2018, creating time series of the spatial distribution and intensity of coccolithophore, diatom and Phaeocystis blooms. We confirm a north-eastward expansion in coccolithophore bloom distribution, identified in previous studies, and suggest an inferred increase in chl-a concentrations, reported by previous researchers, may be partly explained by increasing frequencies of Phaeocystis blooms. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
| Original language | English |
|---|---|
| Article number | 20190357 |
| Number of pages | 16 |
| Journal | Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
| Volume | 378 |
| Issue number | 2181 |
| Early online date | 31 Aug 2020 |
| DOIs | |
| Publication status | Published - 2 Oct 2020 |
Funding
Data accessibility. The datasets of optical properties used in the construction of the phytoplankton community composition algorithm used in this study are available at [doi:10.5285/97daa7ea-8792-6cff-e053-6c86 abc0dd46] [doi:10.5285/982b6da2-7e11-060a-e053-6c86abc09389] [doi:10.5285/982b6da2-7e12-060a-e053-6c86 abc09389], accompanying datasets for chlorophyll-a concentration are available at [doi:10.5285/97daa7ea-8793-6cff-e053-6c86abc0dd46] [doi:10.5285/982b6da2-7e13-060a-e053-6c86abc09389] [doi:10.5285/982b6da2-7e14-060a-e053-6c86abc09389] MODIS-A data is available from NASA’s website for ocean-colour. [https://oceancolor.gsfc.nasa.gov/data/10.5067/AQUA/MODIS/L3M/RRS/2018/] Authors’ contributions. A.O. carried out analyses and drafted the manuscript. H.A.B. supervised analysis and the drafting of the manuscript. T.P. edited the manuscript. B.N. assisted in the interpretation of the significance of our results for the structure of benthic communities. I.K. set up Hydrolight simulations. All authors read and approved the manuscript. Competing interests. The authors declare that they have no competing interests. Funding. This research was funded by the Natural Environment Research Council (NERC) grant no. NE/P006507/1. Acknowledgements. We acknowledge D. McKee of the University of Strathclyde 16 Richmond St, Glasgow G1 1XQ, for assisting in the configuration of Hydrolight. We acknowledge S. Sathyendranath of the Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, for assessing the validity of our correction scheme for temporal drift.
Keywords
- Arctic
- climate
- ocean-colour
- phaeocystis
- phytoplankton
- remote-sensing