RED TIDES

By Stella Angeli

Back ground taken from: http://biology.unm.edu/ccouncil/Biology_203/Images/Protists/dino1.gif

What is red tides?• Red tide is a common name for a

phenomenon known as algal bloom, that occurs when toxic, microscopic algae in sea water proliferate to higher than normal concentration often discoloring the water red, brown, green or yellow.

• World distribution: Mexico, Texas, Florida, South and North Carolina and others.

• Most blooms last three to five months and may affect hundreds of square miles.

• As the bloom increases the density of red tide organisms increase to several million cells in each liter of sea water, creating visible patches near the water’s surface.

Picture taken from: www.whoi.edu/redtide/

Causes of red tides• The causes of red tides are unclear but experienced scientists have arrived at the

conclusion that some specific factors might have caused the phenomenon:

Result of human activities

Coastal upwelling, a natural result of the movement of certain ocean currents

Coastal water pollution

Systematic increase in sea water temperature

Iron-rich dust influx from large desert areas such as the Saharan desert

El Niño events (ocean-atmosphere phenomenon)

Background taken from: http://www.hkredtide.org/eng/images/Figure_1AlgalGrowthfactor.jpg

• Kills fish, invertebrates such as certain clams and oysters, other marine mammals such as dolphins, and water fowl and other birds.

• On humans health problems

Tingling in lips, tongue and throat

Diarrhea, vomiting

Asthmatic symptoms

Temperature reversals ́ ΄: cold feels hot and vice versa

Background taken from: http://bp2.blogger.com/_QCWLAhyamfg/SDdrNx9eEpI/AAAAAAAAEc4/zj533-WqzLk/s1600-h/dead+fish.jpg

Effects

Elimination and treatment in humans• Researchers at Florida International University in Miami are experimenting with

using 640-kilohertz ultrasound waves that create micropressure zones as hot as 3,700 °C. This breaks some water molecules into reactive fragments that can kill algae.

Treatment in humans

Filter masks(asthmatic

symptoms)

Intravenous fluids

Antiemetics

Asthma Medications : Albuterol,

Dipheniramine, Cromolyn, Prednisone,

Brevenal,bronchodilators

Which organism causes the red tides? • The organism that causes the red tides is a microscopic alga called Karenia brevis,

which produces strong chemical brevetoxins that can harm manatees and many other species of aquatic life.

Initiation and Transport

The initiation of Karenia brevis happens in four stages:

Karenia brevis population is first introduced into an area Growth, during which the population steadily increases Maintenance, during which the bloom may be maintained in a circulation feature

offshore or moved inshore by wind and currents Dissipation/termination. Mechanisms that contribute to this stage, such as winds

and currents, may disperse the cells, introduce new water masses, or move the bloom to a different area.

Background taken from: http://www.marine.usf.edu/microbiology/images/k-brevis-scan.jpg

Karenia brevisClassification

Kingdom: Alveolata

Phylum: Dinophyta

Class: Dinophyceae

Order: Gymnodiniales

Background taken from: www.whoi.edu/redtide

Shared defining characters

Picture taken from: http://dinos.anesc.u-tokyo.ac.jp/plankton/figure/Karenia_brevis.jpg

Kingdom: Protista

Flagella

Chloroplasts

Nucleus

Single cells

Phylum: Dinophyta

ChloroplastsSpiraling swimming motion

2 flagellaNucleusTheca

Grooves

Shared defining characters

Picture taken from: http://dinos.anesc.u-tokyo.ac.jp/plankton/figure/Karenia_brevis.jpg

Class: Dinophyta

Apical plateSulcusThecal surfaceChloroplastsOval shapeRidges

Order:Gymnodiales

Sulcus located in the intermediate region of the cingulumApical groovesChloroplastsFucoxanthinCingulumNucleus

Features • Karenia brevis is a photosynthetic dinoflagellate.

• Cells are squarish in outline and are strongly dorso-ventrally flattened. The girdle is not or only slightly displaced.

• Length: 23-24µm

• Width: 24-36µm

• Depth: 10 to 15 µm

Background taken from: http://www.liv.ac.uk/hab/Data%20sheets/k_brev/fig4.htm

Features (2)• Apical groove- at the anterior part of the cell

extending on both the ventral and dorsal sides.

• Chloroplast-contains chlorophyll

• Cingulum (girdle) -A furrow encircling the cell

• Cingular ridges-Longitudinal ridges in the cingulum

• Fucoxanthin-A brownish accessory pigment used in capturing energy.

• Longitudinal and transverse flagellum-like a rudder, steers the cell-when beating propels the cell.

• Nucleus

• Sulcus-The longitudinal area on the ventral surface of the cell

• Theca (also called cell covering or cell wall)- Multiple membrane layers contains vesicles, bladderlike cavities

Picture taken from: http://www.floridamarine.org/images/articles/17864/17864_3359.jpg

Karenia brevis detector

“Breve Busters optically detect Karenia brevis blooms by comparing light absorption by particles in ambient water to the light absorption fingerprint that is characteristic of K. brevis. That comparison yields a Similarity Index (SI) which is related to the fraction of phytoplankton community biomass contributed by K. brevis. Values of SI below 0.5 indicate less than 10% K. brevis, values over 0.8 indicate greater than 90% K. brevis.” (Sarasota Operations Coastal Ocean Observation Lab)

Picture taken from: http://coolgate.mote.org/socool/images/BreveBuster.jpg

Background is taken from: Dr. Barbara’s Kirkpatrick lecture( START Board Member)

Programs associated with red tides - Study what causes HABs and how they can be predicted and

prevented

• NOS Programs

• NOAA Marine Biotoxins Program • IOC Harmful Algal Bloom Programme

• ECOHAB program- Florida etc.

References• Article from: Environmental health ,Harmful algal bloom, 2008• Article from: Fish and Wildlife Research Institute, Red Tides in Florida• Article from: Laurin Publishing, 'FlowCytobot' Detects Blooms, 2008• Article from: Roth P. 2005. The microbial community associated with the Florida red

tide dinoflagellate Karenia brevis: algicidal and antagonistic interactions. MS thesis. The College of Charleston, Charleston, South Carolina.

• Article from: Anderson, D.M. 1995. ECOHAB: the ecology and oceanography of harmful algal blooms: A national research agenda. Woods Hole Oceanographic Institute.

• Article from: Hansen et Moestrup, 1989,Karenia brevis (Davis)• Article from: Earth Observatory,NASA Satellites Detect “Glow” of Plankton in Black

Waters,2004• Article from: National Ocean Service, Harmful Algal Blooms,2007• Article from: Ocean World ,Red Tides,2004• Article from : Shifting Baselines Blog, Can Red Tide Make You Sick?,2005• Article from: National Centers for Coastal Ocean Science, Silver Spring,2008, MD., USA• Article from: Journey North, What is red tide?, 2003