Innovative Spectral Characterisation Of Beached Pelagic Sargassum Towards Remote Estimation Of Biochemical And Phenotypic Properties
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Date
2023
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Journal ISSN
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Publisher
Science of the Total Environment
Abstract
In recent years, pelagic sargassum (S. fluitans and S. natans, henceforth sargassum) macroalgal
Blooms have become more frequent and larger with higher biomass in the Tropical Atlantic region.
They have environmental and socio-economic impacts, particularly on coastal ecosystems, tourism,
fisheries and aquaculture industries, and on public health. Despite these challenges, sargassum
biomass has the potential to offer commercial opportunities in the blue economy, although it is
reliant on key chemical and physical characteristics of the sargassum for specific use. In this study,we aim to utilise remotely sensed spectral profiles to determine species and morphotypes at different
decomposition stages and their biochemical composition to support monitoring and valorisation of
sargassum. For this, we undertook dedicated field campaigns in Barbados and Ghana to collect
the first time, in situ spectral measurements between 350 and 2500 nm using a Spectra Vista Corp
(SVC) HR-1024i field spectrometer of pelagic sargassum-stranded biomass. The spectral
measurements were complemented by uncrewed aerial system surveys using a DJI Phantom 4 drone
and a DJI P4 multispectral instrument. Using the ground and airborne datasets, this research
developed an operational framework for remote detection of beached sargassum and created
spectral profiles of species and morphotypes and decomposition maps to infer biochemical composition.
We were able to identify some key spectral regions, including a consistent absorption feature (920 –
1080 nm) found in all of the sargassum morphotype spectral profiles; we also observed distinction
between fresh and recently beached sargassum, particularly around 900–1000 nm. This work can
support pelagic sargassum management and contribute to effective utilisation of the sargassum
biomass to ultimately alleviate some of the socio-economic impacts associated with this emerging
environmental challenge.
Description
Research Article
Keywords
pelagic sargassum, remote, phenotypic properties