Wild Tobago

What are the possible applications of the seasonal influx of Sargassum on our island shores? Dr Anjani Ganase considers the research and looks at some of the ways that Sargassum is already used. While sargassum, brown fleshy macroalgae, is known and readily used in many Asian countries, in the Caribbean, it is mostly regarded as a nuisance. While some species of sargassum grow attached to the sea bottom, the oceanic species that we’re exposed to seasonally grows on the surface of the open ocean forming great seaweed rafts. These rafts create shelter and a source of food for marine creatures out at sea, but when they enter shallow coastal areas, they smother and entangle marine life, and decay on our beaches and wetland habitats. Since 2011, these golden tides – rafts of sargassum –- are regularly washing ashore on Caribbean and American coasts in large quantities. The two common oceanic sargassum species identified are Sargassum natans and Sargassum fluitans...

It’s not too early to begin preparing for summer sargassum.   Dr Anjani Ganase reviews the latest Sargassum White Paper generated by the United Nations Environmental Programme. The big picture requires trans-Atlantic cooperation - West Africa and Brazil   to fully understand the annual sargassum influx .   Since 2011 and persisting to today, sargassum has been washing up on beaches and coasts of the Caribbean and South and Central America as regular summer events. The highest amounts to date were 27 million tonnes (estimated) of sargassum washed up in 2018; with 20 million tonnes in 2019.   Amazon and Sahara While the two species of sargassum ( S. natans and S. fluitans ) that wash up on our shores naturally occur and grow in oceanic gyres (in the mid-Atlantic), the excessive amount of algal blooms transported is new. Scientists are now certain that these blooms are the result of increased nutrient outflow from the Amazonian basin, mixed...

Dr Anjani Ganase reveals the intricate web of life that exists between water and air off our shores As a budding marine biologist, some of my first introductions to the ocean did not include exciting encounters on exotic reefs or swimming with dolphins. Rather we were introduced to the very top layer of the ocean and the marine creatures that lived near the surface of the water, these creatures are referred to as a neuston community. Neuston is a Greek word for “to swim” and “to float”. Skimming a net along the surface of the water, we would find a collection of transparent shapes and drifting forms that were larvae of fish and invertebrates and other marine critters. In her recent publication, Rebecca Helm, Assistant Professor at the University of North Carolina, reviews the complexities of the neuston zone around the world and discusses the threats to these communities that reside in the interface between air and ocean at the “frontline” of impacts from human activities.  Divers...

Anjani Ganase, marine biologist, talks about Sargassum and signs of the changing ocean In recent years, regional news networks have reported on repeated inundation events occurring on many beaches on southern and eastern Caribbean islands from massive amounts of Sargassum seaweed during the summer months. Sargassum on beaches has been seen in Tobago, Barbados and Antigua; the events were first reported in 2011 – 2012, 2014 – 2015 and again in 2016. Furthermore, during 2014, the amount of Sargassum that was washed up appeared to be greater in comparison to 2011, and now, six years later the events seem to have become a common scenario. Coastlines along Brazil and in West Africa have also experienced deluge by the Sargassum. Previous records in the news and scientific reports on these Sargassum inundation events in the southern Caribbean and West Africa are rare. Scientists have begun to investigate whether these events are part of a natural long-term cycle or the result of...