No easy fixes for giant sargassum ‘blob’

| 23/03/2023 | 49 Comments
Cayman News Service
Sargassum in North Sound last year

(CNS): Dubbed the ‘great blob’, the ever-increasing sargassum belt that circulates in the Atlantic has grown to more than 5,500 miles across and is currently moving through our region. Government officials are warning that the belt is likely to wash ashore in the Cayman Islands again this year. But there is no easy fix. Officials will need to tackle influxes as they happen without worsening beach erosion or disturbing turtle nests while maintaining a pleasant shoreline.

Fuelled largely by climate change and the increases in nutrients from countries engaged in terrestrial deforestation, the belt currently weighs an estimated 10 million tonnes and is double the width of the United States. The mass of seaweed doubled every month between November and January, according to the University of South Florida’s Optical Oceanography Lab, which tracks the mass.

Given its size and current movement, the Cayman Islands will not escape influxes in the coming weeks and months.

The Department of Environment (DoE) and the Cayman Islands National Weather Service (CINWS) are tracking the blob, but it remains difficult to predict local stranding events before they occur. A combination of interrelated factors, such as prevailing winds and complicated nearshore currents, contribute to whether floating sargassum lands on local shores.

Responding to questions from CNS, Jennifer Ahearn, the chief officer in the Ministry of Sustainability and Climate Resiliency, said that Cayman is one of many countries that has been impacted by large sargassum blooms over the past decade.

“At this time, there is no ‘one size fits all’ solution to sargassum,” she said. “Each large-scale beaching event is different and responses – whether led by the public or private sector – will need to take these unique circumstances into account to ensure our interventions do not cause unintentional, negative impacts on local habitats and species.”

A natural part of the ocean ecosystem, healthy patches of sargassum are important habitats for fish, crabs, shrimp, turtles and birds. When small amounts come ashore, it naturally washes away or gets buried by wave action, nourishing the beach and stabilizing the shoreline. But it becomes a headache when the seaweed comes in huge quantities or becomes trapped, as was the case in the North Sound last year.

Cayman, like all other destinations in the region, deploys a number of methods to tackle large inundations. Last year government attempted to pump the sargassum out of the water and take it to the dump. But even though around 2,800sqft of the seaweed was pulled out of the sound, once it began to decompose the programme was stopped and the limited parameters of such a method were left for all to see.

Officials have said that this method could be used again, but that would depend on the unique circumstances of the incident, whether they could get to it in time and the potential impacts of the blooms on the natural environment, communities and tourism.

A task force has already been established to clean public beaches and boat ramps. The ministry, the DoE, the weather service and Hazard Management, among other government agencies, will also coordinate a national response in the event of a significant sargassum stranding incident.

Ahearn said the government was actively monitoring the blooms and is prepared to act upon stranding incidents, “whether through clean-ups of public beaches and boat ramps led by the Public Works Department or using new techniques like we did in response to the North Sound stranding event last year”.

She added, “The national response framework will serve to formalise existing roles and responsibilities, and clarify thresholds for mobilising certain agencies.”

The DoE has produced information about seaweed removal and an online inquiry form to help landowners determine when action is needed to address stranded sargassum and when it is best to let nature take its course. Special precautions need to be taken during turtle nesting season when the sargassum is also likely to be washing ashore.

The seaweed is largely benign when it’s in the ocean, giving a home to sea creatures and even making top-quality fertilizer for gardeners after it is rinsed and dried. But when it is stranded in large quantities, it becomes a threat. It can reduce water oxygen levels and light penetration with the potential to negatively affect marine life, and then when it begins to decompose, it becomes a very smelly problem, even an irritant.

Chief Medical Officer Dr Nick Gent said that the sargassum is not a significant risk to human health but produces gas, such as hydrogen sulfide, which can have an unpleasant smell, even producing feelings of nausea. “Being outdoors, such gasses usually disperse rapidly and do not cause injury or illness,” he said.

Because of the quantity of the sargassum, the gasses might not disperse quickly. Then low residual concentrations of hydrogen sulfide can cause irritation to the eyes, nose, and throat. As degrading sargassum contains a complex mix of irritants, direct contact may cause skin rashes and it is recommended that people working to clear the seaweed use appropriate workwear and wash their hands after contact.

For more information on sargassum, including how to remove it from local beaches and its potential uses, visit the DoE website.

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Category: Marine Environment, Science & Nature

Comments (49)

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  1. Don McCulloch says:

    Hi,

    I live in Kwa-Zulu Natal and we employ shark nets about 200m off our swimming beachs. These nets are laid in an alternate pattern ( Google KZN Sharks Board), and are anchored in less than 20m.

    My suggestion to prevent the Sargassum from coming ashore would be to deploy the ropes with-out the nets. The floating sargassum would be caught in the net and towed out to sea. Once in the ocean the line could be pulled through the sargassum leaving it to float away.

    Good luck.

  2. Anonymous says:

    Occam’s Razor.

    The fish and other organisms that eat the sargassum, have been overfished for centuries and its still happening.

    Stop all fishing and nature will solve the problem, as it did even 50 year ago.

    it seems God gave us intelligence but no wisdom

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  3. Anonymous says:

    Yes, like he provided all those frogs for Egypt.
    No blessing here, blud.

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  4. Anonymous says:

    Diesel and a blow torch is all you need.

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  5. Anonymous says:

    Pretty sure this stuff is why there is oil in the Gulf of Mexico. Just let it rot on the beaches and in a few thousand years we’ll all be oil rich.

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  6. Anonymous says:

    I’m interested. In what way is it caused by climate change?

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    • Anonymous says:

      Columbus first documented encounters with Sargassum in his expedition diaries in 1492, and the Sargasso Sea has been documented in scientific publications since 1854.

      Around the same time Florida was going to be underwater if we don’t do something quick.

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    • Anonymous says:

      Google it. It’s not been kept a secret until now, you know.

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    • Anonymous says:

      Higher CO2 levels in air leading to higher CO2 levels dissolved in oceans (Ocean Acidification). Dissolved CO2 promotes accelerated plant growth (plants use CO2 to grow, and produce Oxygen).
      Warmer temps, excess CO2, excess fertilisers dumped into seas from industrial farming, all combine to create massive blooms of Sargassum. Way more than at any time in history.

      Unfortunately, it’s not even close to enough plant growth to trap and store the excess CO2, and reduce the impact on climate by any meaningful amount.

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    • Anonymous says:

      Assuming you’re asking out of ignorance and a good faith desire to learn, warming ocean temperatures and large scale industrial runoff into the ocean have presented favorable conditions for seaweed growth.

      We all love a hot plate of food, seaweed as well.

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    • Anonymous says:

      I’m going to go ahead and guess here. Maybe the sea is alot more warmer than it used to be and now the seaweed start to release alot more into the ocean now because of the warmer temperatures.

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    • Anonymous says:

      Animal waste and fertiliser runoff from massive African factory farms – so that we can eat steak, bacon, and consume 20 chickens in a single order of hot wings. We don’t pause to think where stuff comes from.

  7. Guido Marsupio says:

    Fix the problem before it hits the beach, not after. Need some sort of protective floating boom like they use for oil spill containment. Any Marine Engineering or Remediation folks out there?

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    • Anonymous says:

      The Ocean Cleanup, they are the experts. Google

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    • Anonymous says:

      Yes, marine engineer here.

      To stop this coming ashore would require a vast expenditure. Can see it cost $10m +, and still only being partially effective.

      combine that with the massive restrictions this would cause for watersports and fishing, as it would involve a hundred miles of boys, nets, anchors, and boats constantly maintaining all that infrastructure.

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      • Guido Marsupio says:

        Thanks, marine engineer! How about this – a V-shaped line of containment buoys oriented in the predominant direction (wind? current?) to route the sargassum AROUND the islands (well, 3 sets of them). Less boat restriction, less cost…

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        • Anonymous says:

          Multiply cost a thousand-fold. (Deep-water anchoring is possible, its just really very expensive. Plus the cost of the shielding material that would withstand the conditions, etc., etc.,)

      • Anonymous says:

        Thanks for the perspective, Marine Engineer. Would a V-shaped pattern of floating buoys pointed in the direction of the prevailing wind and current be better? Would need to be as wide as the island but still smaller and less expensive, and easier to get around by the boats.

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    • Anonymous says:

      To fix the problem you need to reforest the Amazon basin and ban the use of fertilizer across large swathes of South America and West Africa.

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      • Anonymous says:

        You ignored North America and Europe? Hmnnn… It is one big ocean. (Yes, I understand currents, however, fixing a minority of the problem and ignoring the majority of the cause is band-aiding a severed limb).

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        • Anonymous says:

          Ummm, no. You do not understand currents…

          Just because the plastic washing up on our beaches has French writing on it, does not mean it is from France.

          Europeans (and North Americans) can be directly blamed for many things, but Sargassum washing up on our beaches isn’t one of them. That one is most directly attributable to rainforest destruction and agriculture, primarily in Brazil.

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    • Anonymous says:

      Filling in the mangroves on Grand Cayman is what is causing the seaweed to increase. Every house lot that is created here the seaweed doubles, wait until we extend the east / west arterial road to frank sound, you’ll be able to walk from here to africa across the atlantic on seaweed.

  8. Anonymous says:

    It makes Sunday brunch at Calypso Grill and Tukka quite frightful with the honk from the seaweed.

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  9. Anonymous says:

    …”The ministry, the DoE, the weather service and Hazard Management, among other government agencies, will also coordinate a national response…”

    What a joke. these agencies can’t communicate efficiently within their offices, there is no way they can communicate between offices for a positive national response.

    Actually, the ‘National response’ will be “Sargassum, welcome to our shores”!

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  10. Anonymous says:

    Don’t worry Ahearn is on it, and has the situation all under control. Plenty of smelly H2S gas in that statement.

    She failed to mention that local deforestation and increased release of largely untreated septic tank effluent into the groundwater has also contributed to the regional problem.

    She will most likely recommend another PwC project to investigate this too before years end.

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    • Hubert says:

      On Little Cayman one can now start to see the largely untested septic tank effluent damaging the beach along Crosswinds and Little Cayman Resorts.

      10 years ago it was beautiful and clear along the beaches there. 😭 😿 😢

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      • Anonymous says:

        Southern Cross Beach not Crosswinds.

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        • Johnny Canuck says:

          I was at Southern Cross earlier this month and was shocked and saddened at how the beach and water quality had deteriorated since I was last there 5 years ago.

          CIG Ministry of Environment better start enforcing regs or Little Cayman will be destroyed for tourists in a few years.

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          • Peter Hillenbrand says:

            I live next to the Southern Cross Club. I am curious what you mean by “beach and water quality had deteriorated..” When the sargo washes ashore in quantity it does affect the shoreline ecosystem, but the beach and water quality has not been adversely affected long term. In the instances when the sargo washes up in quantities too great to effectively clear, which has happened 3 times since 2018, the beach and shore do turn nasty, but those conditions to date have been temporary. If you are referring to septic issues, I know of only one place on Little Cayman where septic issues are causing near shore harm. Hopefully DoE is reacting to this case.

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            • Johnny Canuck says:

              If you look in front of the beach in front of your resort you will clearly see algae / seaweed / sargo which is dark brown / black which has sunk to the bottom. One now has to swim out 150 / 200 yards to hit clear turquoise water. You must walk through the algae/ seaweed / Sargon to get to the clear water from your beach.

              It was not like that 5 years ago. My whole family noticed this change when we visited the beach earlier this month.

              I regret I did not take a picture but will on my next visit but it is clear to see. The date of my visit to the beach was March 10 but we did not stay at Southern Cross.

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              • Peter Hillenbrand says:

                The entire shoreline of South Hole Sound is Turtle Grass. That has been there for as long as I can remember. This has always stretched out 75 – 100 M to reach the touquois sand bottom. That is not new and would have been there 5 years ago when you last visited. the sargo is relatively new (2018 on Little Cayman), and that is a pain for everyone. I went down to the SCC after lunch today, walking on the beach. There is no unnatural algae besides the turtle grass and a bit of sargassum. No one along the beach from the airport to the start of the mangroves in South Hole Sound has septic discharge that is not approved by the DoH. I have never seen unnatural algea blooms caused by sewage discharge, if that is what you are referring to, along this stretch. SCC’s septic system was last updated to higher (current) standards in 2010. I am not sure what it was you experienced, but if it was anything besides the Turtle Grass or sargassum, it was a weird one time event that I have never seen myself. For me Little Cayman is still a pristine wonderland. If you, hopefully, visit again and see this phenomenon, please do report it to SCC staff. Thanks Johnny.

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    • Anonymous says:

      MI6

  11. Anonymous says:

    We can use it as biofuel or fertilizer. St.Lucia’s Algas has been in the news on this. Enough “free” renewable fertiliser for every farm in America: https://www.algasorganics.com

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    • Anonymous says:

      Yes it can be refined, but who keeps the hard meatls and arsenic? I guess you could burn it in the dump, opps, I mean take it to the dump…

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    • Anonymous says:

      Our ✝️Lord provides.
      Sargassum is excellent fertilizer ~ market it.

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  12. Anonymous says:

    It doesn’t make a good fertiliser, unlike other types of seaweed, as it contains high levels of arsenic that can contaminate ground water and soil.

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    • Anonymous says:

      This island is awash with arsenic from burned storm debris, what’s a little bit more in your diet? Besides it keeps the cancer doctors in business and slowly preserves your body so you don’t need embalming when you finally kick the bucket.

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    • Anonymous says:

      On its own, in unrefined form that’s correct, but those can be separated out and sold as useful byproducts in their own right. Keep in mind we also don’t pour crude oil into our vehicles. Some refining is necessary to make the crude useful as automotive gasoline. Nobody is throwing away crude oil because it’s too hard to figure this out.

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      • Anonymous says:

        You are not suggesting we refine it here!! Pleeease. We can’t even recycle glass, ban plastic & styrofoam or fix the dump!!!!

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