Presentation on theme: "RED TIDES By Stella Angeli"— Presentation transcript:
1 RED TIDES By Stella Angeli Back ground taken from:
2 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:
3 Causes of red tidesThe 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 activitiesCoastal upwelling, a natural result of the movement of certain ocean currentsCoastal water pollutionSystematic increase in sea water temperatureIron-rich dust influx from large desert areas such as the Saharan desertEl Niño events (ocean-atmosphere phenomenon)Background taken from:
4 EffectsKills fish, invertebrates such as certain clams and oysters, other marine mammals such as dolphins, and water fowl and other birds.On humans health problemsTingling in lips, tongue and throatDiarrhea, vomitingAsthmatic symptomsTemperature ́reversals΄: cold feels hot and vice versaBackground taken from:
5 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 humansFilter masks(asthmatic symptoms)AntiemeticsAsthma Medications : Albuterol, Dipheniramine, Cromolyn, Prednisone, Brevenal,bronchodilatorsIntravenous fluids
6 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 TransportThe initiation of Karenia brevis happens in four stages:Karenia brevis population is first introduced into an areaGrowth, during which the population steadily increasesMaintenance, during which the bloom may be maintained in a circulation feature offshore or moved inshore by wind and currentsDissipation/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:
9 Shared defining characters Apical plateSulcusClass: DinophytaThecal surfaceChloroplastsOval shapeRidgesSulcus located in the intermediate region of the cingulumOrder:GymnodialesApical groovesChloroplastsFucoxanthinCingulumNucleusPicture taken from:
10 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: 23-24µmWidth: 24-36µmDepth: 10 to 15 µmBackground taken from:
11 Features (2)Apical groove- at the anterior part of the cell extending on both the ventral and dorsal sides.Chloroplast-contains chlorophyllCingulum (girdle) -A furrow encircling the cellCingular ridges-Longitudinal ridges in the cingulumFucoxanthin-A brownish accessory pigment used in capturing energy.Longitudinal and transverse flagellum-like a rudder, steers the cell-when beating propels the cell.NucleusSulcus-The longitudinal area on the ventral surface of the cellTheca (also called cell covering or cell wall)- Multiple membrane layers contains vesicles, bladderlike cavitiesPicture taken from:
12 Karenia brevis detector Picture taken from:“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)
13 Background is taken from: Dr Background is taken from: Dr. Barbara’s Kirkpatrick lecture( START Board Member)
14 Programs associated with red tides - Study what causes HABs and how they can be predicted and preventedNOS ProgramsNOAA Marine Biotoxins ProgramIOC Harmful Algal Bloom ProgrammeECOHAB program- Florida etc.
15 ReferencesArticle from: Environmental health ,Harmful algal bloom, 2008Article from: Fish and Wildlife Research Institute, Red Tides in FloridaArticle from: Laurin Publishing, 'FlowCytobot' Detects Blooms, 2008Article from: Roth P 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 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,2004Article from: National Ocean Service, Harmful Algal Blooms,2007Article from: Ocean World ,Red Tides,2004Article from : Shifting Baselines Blog, Can Red Tide Make You Sick?,2005Article from: National Centers for Coastal Ocean Science, Silver Spring,2008, MD., USAArticle from: Journey North, What is red tide?, 2003
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