A PhD candidate at the World Maritime University’s WMU-Sasakawa Global Ocean Institute, Ms Kristie Alleyne, has published as lead author some of her research findings in Scientific Reports Nature.com, which is one the world’s most cited multidisciplinary academic journals. Ms Alleyne is a member of the WMU-Sasakawa Global Ocean Institute’s “Closing the Circle: Marine Debris, Sargassum and Marine Spatial Planning” Programme, exploring challenges and potential solutions to the sargassum and the plastic pollution threat in the Eastern Caribbean with the support of generous funding from The Nippon Foundation and in partnership with CERMES at the University of the West Indies (UWI), Barbados.
As part of her PhD project, Ms Alleyne conducted spatiotemporal analyses of sargassum influx events in Barbados. In her recent publication in the Scientific Reports of Nature Journal, she and her co-authors (Professor Francis Neat at WMU, Professor Hazel Oxenford at UWI-CERMES, Dr. Henri Valles at UWI and Dr. Donald Johnson at the University of Southern Mississippi) quantified the species and morphotype composition of sargassum strandings in Barbados and tested if this was related to separate oceanic origins and routes traveled using a backtracking algorithm. Interestingly, they found significant seasonal variation in the relative abundance of three morphotypes that could be traced to two distinct easterly sub-origins and/or transport pathways. The first sub-origin/transport pathway lies around 15° N and travels directly E–W across the Atlantic, the second sub-origin/transport pathway lies south of 10° N and takes a more meandering route coming close to the coast of South America.
hese research findings are significant because of the mass proliferation of pelagic sargassum in the Tropical Atlantic. This in turn has resulted in major ecological and socioeconomic impacts on regional fisheries and tourism industries in the Eastern Caribbean. The unprecedented occurrence of sargassum in the Caribbean has been tracked to a ‘new’ bloom region known as the North Equatorial Recirculation Region (NERR) encompassing the area between the South Equatorial Current and the North Equatorial Counter Current and extending from Africa to South America. The vast biomass of sargassum presents a plethora of management challenges when it washes ashore but also represents significant commercial opportunities. However one challenge to the valorisation of this new resource is the uncertainty in the supply of pelagic sargassum and morphotypes. Sargassum arriving in Barbados consists of two major species (Sargassum fluitans and S. natans), with three commonly occurring morphotypes (S. natans I, S. natans VIII and S. flitans III). Oceanic mixing tends to blend the morphotypes together making it difficult to determine if there are regions of the NERR that favor bloom and growth of the distinct types. Research on the variability in morphotype composition is thus necessary to better understand factors responsible for the continued proliferation of pelagic sargassum and turn a current threat into opportunities.
The identification of these two sub-origins/transport pathways points to resolvability of the complex problem of blooms; why now, why here, what are the dominant parameters that influence growth and mortality? Moreover, the findings of this study are relevant to the developing sargassum industry by providing insights into the potential causes of variation in morphotype composition arriving in the Caribbean. Information on morphotype composition will be important to managers and decision-makers and the interventions they make at different times of the year as the region continues to tackle the complex challenges associated with influx events.
Ms Alleyne points out that scientific forecasts are predicting moderate to severe sargassum influx events in the upcoming months, thus, there are certainly many challenges on the horizon. Nevertheless, she believes that valorisation of pelagic sargassum presents an opportunity to minimize the negative impacts associated with sargassum strandings; however, contamination with plastic and heavy metals presents concerns. In this regard, her research shows that understanding the origins of pelagic sargassum is only one piece of this very complex problem. “The ‘Circle’ is far from closed but the WMU-Sasakawa Global Ocean Institute (GOI) together with CERMES from the University of the West Indies, Barbados are working arduously to understand and address valorization challenges, specifically as it relates to levels of arsenic, in hopes of transforming the Golden Tides into sustainable valorization opportunities”, said PhD Candidate Kristie Alleyne. ‘ We have however identified one important piece of the equation that must be resolved if we are to address the impacts of sargassum but much remains to be done research wise’.
In congratulating Ms Alleyne on publishing her research findings in the world-leading journal Scientific Reports Nature.Com, Professor Ronán Long, Director of the WMU-GOI, says that the close working partnership with UWI-CERMES and the support of The Nippon Foundation are both vital for undertaking applied research on what has become a major hazard for coastal communities in the Eastern Caribbean. He is confident that the results can be applied by Barbados and several other Small Island Developing States and further afield in their battle against the ecological and health crisis caused by the mass proliferation of pelagic sargassum due to climate change and other anthropogenic impacts on the marine environment.