Tuesday, December 15, 2015

Red Tide is caused by deadly Dinoflagellates. Beware!

 The biblical story of the Nile turning red, as in one of the plagues of Egypt during the time of Moses, was a case of the Red Tide phenomenon.
Dr Abe V Rotor 

The culprit in Red Tide is another algal bloom, but is located at coves and harbors. Organic materials and wastes flow down the river during floods and onto the sea where they fertilize the red tide dinoflagellates. In the Philippines the red tide species is Pyrodinium bahamense compressa. This happens when the water is warm and there is plenty of sunlight. The organisms multiply very rapidly that due to their enormous numbers, the water appears red, hence the term Red Tide.

 Stages and diversity of the Red Tide phenomenon.  Bioluminiscence is a property of the Noctiluca dinioflagelate.  Other dinoflagellates likewise "glow" in water

Fish kill is a result of feeding on red tide organisms. The baleen whale which is a plankton feeder is among the most vulnerable victims, in spite of its huge aze.

 Dinoflagellates of Phylum Pyrophyta include Gonyaulax and Pyrodinium. 

The biblical story of the Nile turning red, as in one of the plagues of Egypt during the time of Moses, was a case of the Red Tide phenomenon. One would appreciate this better on entering Cairo coming from Sinai desert across the Suez Canal. It was one of the most beautiful sights in the region - the legendary Nile flowing into the vast blue Mediterranean Sea. The banks of the Nile are among the best farmlands in the world. But lately, during flood seasons the Nile deposits its load of silt and organic delta-building materials, consequently obstructing water flow. The area has become as a cradle of the Red Tide.


Do not eat green mussel (tahong), oyster (talaba), halaan shell when the red tide flag is up.  Take heed of the warning of DOH.  Shellfish accumulate poison - Paralytic Shellfish Poison or PSP - a saxitoxin, through "luxury feeding" without apparent effect on these shellfish.


Facts about Red Tide 
Red tide is a colloquial term used to refer to one of a variety of natural phenomena known as harmful algal blooms. It is  used to refer more broadly to other types of algal blooms as well.

  1. Red tides are not necessarily red and many have no discoloration at all.
  2. They are unrelated to movements of the tides.
  3. The term is imprecisely used to refer to a wide variety of algal species that are known as bloom-formers.


 ...it appears that humans sometimes exacerbate this phenomenon. When great amounts of industrial and human wastes are discharged into the water, the result can be an oversupply of certain nutrients. This can trigger the heavy population growth of dinoflagellates. Available oxygen in the water is soon depleted, resulting in large fish kills.


Notable occurrences (Internet)

1793: The first case occurring in British Columbia, Canada
1840: No deaths of humans have been attributed to Florida red tide, but people may experience respiratory irritation (coughing, sneezing, and tearing) when the red tide organism (Karenia brevis) is present along a coast and winds blow its aerosolized toxins. Swimming is usually safe, but skin irritation and burning is possible in areas of high concentration of red tide.
1972: A red tide was caused in New England by a toxic dinoflagellate Gonyaulax. The red tides caused by the dinoflagellate Gonyaulax are serious because this organism produces saxitoxin and gonyautoxins which accumulate in shellfish and if ingested may lead to paralytic shellfish poisoning (PSP) and can lead to death.
1976: The first PSP case in Sabah, Malaysian Borneo where 202 victims were reported to be suffering and 7 deaths.
2005: The Canadian red tide was discovered.
2011: Northern California.
2011: Gulf of Mexico
2012: NSW Australia
2012 Englewood Florida
2013: January, red tide occurred again in Sabah with two fatalities.
2013: Again in Florida, fish kill had a negative impact on tourists, and caused respiratory issues for beach-goers.
2014: August, Massive 'Florida red tide' 90 miles long and 60 miles wide.
2014: November, Hibiscus Coast Auckland, New Zealand. On various beaches...
2015: June, 12 persons hospitalized in Bohol for red tide poisoning.
2015: August, several beaches in the Netherlands were plagued. Government institutions dissuaded swimmers to go into the water.
2015: September, Gulf of Mexico.
2015: October, again in Gulf of Mexico and coast of Florida.

·         Occurrence of Red Tide in Philippine Bay
  • Rapid increase in population, urbanization and industrialization reduce the quality of Philippine waters.  The discharge of domestic and industrial wastewater and agriculture runoff has caused extensive pollution of the coastal water bodies.  This effluent is in the form or raw sewage, detergents, fertilizers, heavy metals, chemical products, oil and solid waste.
  • The extent of water pollution in the Philippines Bays can be gleaned from the frequent occurrence of red tide since it first came to the attention in 1983.  Red tide usually occurs when high organic loading from rivers drain into bays resulting in harmful algal blooms (HABs).
  • From 1983 to 2001, a total of 42 toxic outbreaks have resulted in a total of 2,107 paralytic shellfish poisoning cases with 117 deaths.  Earlier, only a few coastal areas of the country were affected in scattered locations, but today, this has grown to a total of 20 coastal areas.
  • ·For Manila Bay, during the 1992 Pyrodinium red-tide outbreak, around outbreak, around 38,500 fisherfolks were displaced from their livelihood due to the red tide scare.  Estimated economic losses for displaced fisherfolks was PhP 3.4 billion (in 2002 prices). (Environmental Monitor 2003)
  • An Inter-Agency Committee on Environmental Health chaired by the Department of Health (DOH) created the National Red Tide Task Force (NRTTF) composed of different government agencies and academic institutions chaired by the Bureau of Fisheries and Aquatic Resources, Department of Agriculture.National Red Tide Task Force (NRTTF) is mandated to monitor toxic red tides in our country.  This is to protect the public from the illness and death caused by the red tide toxin and also to mitigate its negative impact to the shellfish industry.  A regular issuance of the red tide update is also being undertaken. (Internet) ~

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