Sargassum Menace

For the last several years the coastlines of Caribbean islands have from time to time been clogged with sargassum. It is a seaweed that floats on the surface of the sea, inevitably reaching the coastlines of landmasses in its path. 

Besides the unsightly look of the seaweed covering the beaches, the stinking smell of the sargassum as it decays is worse than the smell of a thousand wet farts.

It does not matter if the sargassum menace is caused by global warming or a freak of nature. What matters is that it represents a formidable threat to the economic survival of small island developing states in the region. Since 2011 sargassum has been an economic threat to Caribbean islands and unsurprisingly, it has not provoked a collective response from our leaders. 

It seems foolhardy for economic planners in Barbados and neighbouring territories to be committing millions, billions of dollars to the tourism plant and at the same time ignore the threat sargassum posses to the sector. After a decade the region seems helpless to fight back. We have to find a solution to trap and collect the seaweed at sea before it pollutes our beaches. Who wants to travel thousands of miles to have the rotting stench of sargassum assail the nostrils and the unsightly look it presents?

The following link is presented as a positive step to addressing the issue. Why are we not sensing greater urgency from leaders in the region about combating the threat sargassum posses to the livelihood of the region?

Stinky seaweed is clogging Caribbean beaches – but a New Zealand solution could turn it into green power and fertiliser

Published: May 31, 2022 3.16am BST

Thanks Bentley!

The Adrian Loveridge Column – Automated Passport Kiosks and Sargassum Seaweed

Have we reached a crossroads or what the more sceptical may refer to as an almost insurmountable hurdle in our tourism development?

Returning on a near capacity Virgin Atlantic B747-400 from Gatwick last week, I was initially surprised that just before landing a member of the flight crew advised over the PA to try and get off the aircraft as soon as possible. It was explained a British Airways flight was landing right behind us and the hurry up was to to try and minimize the long queues in immigration. In fact, not only the British Airways B777-200 followed us but also an American Airlines B738.

By now, under not one but two Governments, we would have thought the millions of dollars spent on the Automated Passport Kiosks be fully operational for all arrivals. But no, over two years (November 2016) after installation they are restricted to a very few, seemingly just Barbadians and those with permanent status in Barbados.

Even before the British Airways plane had barely opened its doors the long line of Virgin passengers were already out the terminal door. If the other two aircraft had been close to full that would have meant up to almost 1,000 passengers (depending on model) would be standing in line, within seconds of arrival. Among them of course, many small children and elderly persons!

What seems amazing is that the carrier – in this case, Virgin Atlantic  fully understands the challenges our limited Immigration facilities pose.  Why are our own tourism officials and Government (s) appear not to be able or willing to correct the problem?

The naysayers will point out that this is not a situation unique to Barbados and delays will be experienced in other destinations like entry airports in the United States including Miami, Charlotte and New York. Other Caribbean territories have addressed this by implementing US pre-clearance in their own states but sadly, not so far, Barbados. Even where this had not been introduced, everyone has to stop and think for a moment that the United States in not a tourism dependent country and similarly, neither is the United Kingdom or Canada.

Staying with the ‘dependency’ issue, the Prime Minister, recently highlighted the existing and potential treat of Sargassum seaweed and is quoted as stating it could be ‘as devastating to national economies as a strong tropical storm or category 1 hurricane’. Few can argue with her conclusion, especially if you have witnessed the consequences as I recently did on the French West Indian island of St. Martin.

Our visitors largely comprehend the nature driven challenge, but need to know that we are seriously trying to cope with the problem, even on a localized basis. Some do not understand why our comparatively large ‘Defence Force (BDF)’ cannot be mobilized, at least in public areas,  where a positive even if temporary difference could be made.

Naturally, it is not what they are trained for but if this is really the threat that is portrayed by those in the highest office, doesn’t it make sense?

Final Reply by Dr. Lucas Responds to Peter Webster’s Deleterious Effect of Seaweed on Soils Piece

The Editor

Barbados Underground

Bridgetown, Barbados

West Indies

Dear Sir/Madam,

In a blog (4th. August) in reply to my last article: Webster had this to say: “The only thing obvious about this statement is the contradiction i.e. that the sodium is leached and yet there is an accumulation. Barbados limestone soils are well drained and there can be no accumulation of sodium ions which are readily leached”.

My reply is as follows: “Webster is obviously out of his depth when it comes to surface chemistry and West Indian soils. Let me explain again for his benefit that since sodium has a smaller ionic volume/radius it not adsorbed as readily as potassium and therefore is leached down the soil profile. The black earth soils of Barbados have been classified by Vernon And Carroll(1965, ICTA) as soil type 30. Soil type 30 is what is called a montmorillonite soil ( and has what is known as a two -in one lattice structure). This soil type has a high clay content as can be readily attested after a rainfall by walking through it. The soil adheres to one shoes and is difficult to handle. Indeed after downpours pools of water are often seen dotting the surface of these soils. I will also now explain what is meant by capillary action that I alluded to, that Webster again selectively does not cite. After soluble salts have leached down the soil profile, when a period of prolong dry weather occurs, the soil pore-space acts like what happens when blotting paper is dipped in water. In the latter case water rises up the blotting paper by capillary action. A similar event occurs in the soil. Since there is a water deficit between the water content of the surface (lacks water) and the soil solution down the profile that contains salts (sodium, since I am dealing seaweeds), there is upward movement of salt containing water. When this water reaches the surface, solar evaporation takes place and the soil becomes saline.

I want to disabuse Webster of the view that by washing seaweed one can remove the salt it contains. According to TIC Gums product data the sodium content of various purified seaweed products are as follows per 100 grams. There substances have under gone several washing to meet food-grade standards.

Ticagel 121-AFG Powder Sodium: 619 mg.

Agaroid RS-507 Powder Sodium :

TIC Pretested Agar Agar 100 FCC/NF Powder Sodium: 487mg


Robert D. Lucas, Ph.D.and CFS.

Certified Food Scientist.

Dr. Lucas Responds to Peter Webster’s Deleterious Effect of Seaweed on Soils Piece

Submitted by Robert D. Lucas, Ph.D. and CFS, Certified Food Scientist


[Barbados Underground]

The Editor

Barbados Underground

Bridgetown, Barbados

West Indies

Dear Sir/Madam,

There was an article in the Nation of 26th July entitled “How to handle sargassum” by Mr. Peter Webster. Webster in paragraph one seems to have a problem with “however, if large concentrations of sodium salts are added to the soil.’In paragraph two he cites some work done in Portugal that indicates sargassum “has a strong potential as functional food ingredient.” These comments of Webster are now dealt with.

All sodium salts are soluble and there is therefore a tendency for these salts to be leached downward. In periods of drought, sodium salts rise by capillary action to the surface of the soil. It ought to be obvious that with the repeated addition of seaweed to the soil, there will be an accumulation of sodium in the soil profile; that under dry conditions can rise by capillary action and affect both the salinity and sodic nature of the soil. Is Webster suggesting that the sargassum is only going to be applied once to the soil? Webster conveniently ignored the fact that in paragraph two of my article it is stated “the deleterious effects described by Hunte…can be attributed to the ..development over time of soils that are saline-sodic.” Webster makes an issue of the ratio of potassium (K) to sodium (Na) in the living seaweed In any event K:Na in the living seaweed has nothing to do with what happens when seaweeds are decomposed by microbial action in the soil. As previously stated, since K has a greater ionic volume/radii than Na, it is adsorbed before Na.

I have addressed the uses of seaweeds in food in my article of 14th July in your on-line paper.


Robert D. Lucas,Ph.D. and CFS.

Certified Food Scientist.

What to do with Sargassum

Submitted by Robert D. Lucas,Ph.D. and CFS, Certified Food Scientist

The Editor

Barbados Underground

Bridgetown, Barbados

West Indies

Dear Sir/Madam,

The following is an overview of the uses of seaweed in the food industry. Suggestions are also proposed for prospective uses of the product.

Seaweeds belong to a group commonly called macro-algae or  hydrocolloids in the food industry. The  latter name derives from the propensity of the substances to form viscous dispersions and or gels when dispersed in water  (colloidal sols) and from the extensive hydroxyl groups with which the substances can form attachments with water molecules.. Hydrocolloids are a heterogeneous group of long chain polymers (polysaccharides{sugars} and proteins). Some of the amino acids in the protein chain contain sulfur (for example; methionine). These are broken down by sulfur using bacteria into hydrogen sulfide and other noxious substances. Hydrocolloids are widely used in the food industry because of their ability to modify the rheology of food systems This include two basic properties of food systems namely, flow behavior (viscosity) and mechanical solid (texture)property (Saha,D.and Bhattacharya,S.(2010) “Hydrocolloids as thickening and gelling agents in food: a critical review.” J. Food Sci.Technol. 47:6: 587-597.).

According to McHugh. J.D. 2003. “A Guide to the Seaweed Industry.” FAO. Fisheries Technical Paper #44:: “The seaweed industry provides a wide variety of products that have an estimated total annual value of US$ 5.5-6 billion. Food products for human consumption contribute about US$ 5 billion of this. Substances that are extracted from seaweeds -hydrocolloids – account for a large part of the remaining billion dollars, while smaller, miscellaneous uses, such as fertilizers and animal feed additives,  cosmetics and the manufacture of paper make up the rest.”

Hydrocolloids fall under the heading of functional food additives,. They are widely used in many food formulations to improve quality attributes and shelf-life. The two main uses are as thickening and gelling agents. As thickening agents, they find uses in soups, gravies, salad dressings, sauces and toppings while as gelling agents, they are extensively used in products like jam, jelly, marmalade, restructured foods and low sugar/calorie gels (Saha and Bhattacharya. 2010).

Seaweeds are classified in commerce according to pigmentation as: red(used for agar and carrageenan in the food and microbiology) and  brown or green. Sargassum seaweeds (SW) are brown. Brown seaweeds are used for the manufacture of aginlates for the food industry. Apart from being thickeners, alginates have some applications that are not related to either their viscosity or gel properties. They act as stabilizers in ice cream; addition of alginates reduce the formation of ice crystals during freezing, giving a smooth product  Alginate gels are used in re-structured or re-formed food products. For example, re-structured meats can be made by taking meat pieces, binding them together and shaping them to resemble usual cuts of meat, such as nuggets, roasts, meat loaves, even steaks.They are also used in the controlled release of medicinal drugs and other chemicals. In some applications, the active ingredient is placed in a calcium alginate bead and slowly released as the bead is exposed in the appropriate environment.

Available information on Sargassum natans and fluitans, the two species of primary concern across the Caribbean, is sparse (Michelle Morrison, CPI and Daniel Gray. The Caribbean Council,  Anaerobic Digestion Economic Feasibility Study: Generating energy from waste, sewage and Sargassum Seaweed in the OECS :CPI Report Number: CPI-SP-RP-141(31/01/2017).It was also concluded that it was not economically feasible to generate bio-gas using anaerobic digestion since SW have low biochemical methane potentials (BMP). Anaerobiosis using pure culture techniques were apparently not used. Using pure culture techniques one can swamp the indigeneous microflora of the substrate with the microflora of choice, thereby controlling the rate of the process using continuous anaerobiosis (by using pure cultures other organisms that can divert the production of methane are effectively inhibited. Must also be noted that the carbohydrate content of seaweed as a substrate varies during the course of the season. According to Lenstra and others (.2011).Ocean Seaweed Biomass For large scale bio-fuel production Energy Research Center,Netherlands (ECN) S. natans has the following chemical composition :on a dry weight basis(dw) Proteins;6.59%; Fat 0.54%;Carbohydrate 76.43%; Phosphorus  0.082; Potassium19.56%; Energy (kJ/100g dry matter) 1410.

SW structurely consists of linear polysaccharides made up of 25-30 glucose units linked by(beta) b 1-3 glycosidic bonds. In some cases b1-6 glycosidic bonds occur. Since the cell wall of SW contains cellulose. the biomass must be pretreated and  then (1) treated with (hydrolyzed ) cellulase enzyme systems supplemented with β-glucosidase followed by(2) fermentation with Saccharomyces cerevisiae(yeasts). Having stage(1)immediately followed by stage (2), result in what is known as a two-stage process which is economically more expensive. It is better to have stage (1) and (2) operating simultaneous, using continuous fermentation in the production of alcohol This can be done by the use of immobilized enzyme technology. In immobilized enzymes, the enzymes are enmeshed in a membrane (made of aginlate) which facilitates the reuse of the enzymes reducing costs and increasing reaction efficiencies.

SW can be used as an animal feed for ruminants only at present, since poultry do not have the necessary enzyme systems required to handle b glycosidic links. Feed from SW, has a low protein content  when compared to soy. To augment the protein content, SW can be used as a substrate for the production of single cell protein. Using continuous fermentation techniques, protein yields as high as 40% on a  dry-weight basis can be obtained. Single cell protein can be used in the formulation of non-ruminant rations as I having been advocating for more than twenty years (letters to the Editor, Barbados Advocate). Thinking long term, the gene for the beta glycoside using gene editing techniques can be inserted into a bacterium found normally in the gut microflora of non-ruminants. The edited bacterium with the added gene can then be reinserted into the gut microflora of the non-ruminant by incorporating it into the rations.. The non-ruminant is now able to utilize feeds made from SW.  Alternatively, SW itself can be gene edited and the gene for the  b condition changed to the a state, making it possible to have feed that can be utilized by both ruminants and non-ruminants directly.

Brown macroalgae, Sargassum ssp., are considered as a potential biomass source for energy production due to their relatively fast growth rates, ease of harvesting, and low pre-production cost. Sargassum fluitans, S. natans, and S. filipendula are three of the most abundant macroalgae species found at Puerto Rico’s coasts. The lipids content of Sargassum spp. ranges between 1.0 and 2.5% (total lipids)Diaz-Vazquez and others (2015) “Demineralization of Sargassum spp. macroalgae biomass: selective hydrothermal liquefaction process for bio-oil production.”Front.Energy Res. 3:6..

If the temperature and pressure  of carbon dioxide are both increased  to be at or above its critical point ,it can adopt properties midway between a gas and a liquid. More specifically, it behaves as a super critical fluid above its critical temperature 31.10 °C, (87.98 °F) and critical pressure of 72.9 atm, (7.39 MPa, 1,071 psi), expanding to fill its container like a gas but with a density like that of a liquid. Under these conditions carbon dioxide(CO2) acts as a solvent and removes fats/oils from a product. It is commonly used in the food industry in the manufacture of decaffeinated coffee. This method can be used to extract oil from SW without the residual harmful effects of the use of hexane, the solvent currently in  wide spread use.

SW is prevalent throughout the earth’s oceans. There has been a lot of noise locally about how to handle the problem. As far as I am concerned, there is no reason why the approach used in the fishing industry should not be adopted. With the use of drones and appropriate algorithms or biosensors one can easily detect the position of SW. Using algorithms, the difference in color of the ocean where the SW is versus where it is absent can be used to pinpoint the product. Alternatively, since S.natans has the ability to fix atmospheric nitrogen( by an associated epiphyte or cyanobacteria), a build up of or a depletion of nitrates can be used to detect SW, since the background levels in the ocean will be different. Similarly,the same should hold good for carbon dioxide(CO2) which is utilized during photosynthesis. Finally, there should be a temperature differential, due to the metabolic processes underway in the developing SW and the ocean’s background temperatures.  Lenstra and others (.2011) have outlined measures for fishing and harvesting SW. Recently a Caribbean country purchased two seaweed harvesters. So, instead of waiting for SW to come to Barbados, Barbados should go hunting for it.


Robert D. Lucas,Ph.D. and CFS

Certified Food Scientist.