Innovative spectral characterisation of beached pelagic sargassum towards remote estimation of biochemical and phenotypic properties

TY - JOUR

T1 - Innovative spectral characterisation of beached pelagic sargassum towards remote estimation of biochemical and phenotypic properties

AU - Fidai, Y. A.

AU - Botelho Machado, C.

AU - Dominguez Almela, V.

AU - Oxenford, H. A.

AU - Jayson-Quashigah, P. N.

AU - Tonon, T.

AU - Dash, J.

N1 - Funding Information: This work was supported by the Economic and Social Research Council GCRF (Grant number: ES/T002964/1), a scholarship from Southampton Marine and Maritime Institute, University of Southampton, and the School of Geography and Environmental Sciences, University of Southampton. From the University of Southampton, we recognise Prof. Emma Tompkins for her role as a supervisor and for her leadership and support throughout the project and field campaigns, and Prof. Bob Marsh for his support in Barbados. We also acknowledge and offer our sincere gratitude to the teams at the University of West Indies in Barbados (Micaela Small, Joseph Weekes, Mia Clarke, Kristie Alleyne, Dale Benskin) and University of Ghana (Prof. Kwasi Appeaning-Addo, Dr. Winnie Sowah, Dr. Yaw Atiglo, Michael Kwame-Biney, Bernice Wilmot, Sylvester Egyir), as well as the Environmental Protection Agency Ghana, for hosting us, sharing their expertise and for their contributions to data collection. We thank the Natural Environment Research Council Field Spectroscopy Facility for their training and loaning us the field spectrometer to make this work possible (Loan Reference: 890.0322). Funding Information: This work was supported by the Economic and Social Research Council GCRF (Grant number: ES/T002964/1 ), a scholarship from Southampton Marine and Maritime Institute, University of Southampton , and the School of Geography and Environmental Sciences, University of Southampton . Publisher Copyright: © 2024 The Authors

PY - 2024/3/1

Y1 - 2024/3/1

N2 - 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/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, for 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/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.

AB - 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/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, for 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/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.

KW - Coastal management

KW - Macroalgae

KW - Marine ecosystems

KW - Remote sensing

KW - Sargassum

UR - http://www.scopus.com/inward/record.url?scp=85182030154&partnerID=8YFLogxK

U2 - 10.1016/j.scitotenv.2023.169789

DO - 10.1016/j.scitotenv.2023.169789

M3 - Article

C2 - 38181957

AN - SCOPUS:85182030154

SN - 0048-9697

VL - 914

JO - Science of the Total Environment

JF - Science of the Total Environment

M1 - 169789

ER -