Phytoplankton
Dinoflagellates
Ceratium longipes
human hair
70 microns about the
thickness of a human hair
photo by Bill Andrake
Alexandrium tamarense...
a red tide organism
www.uio.no/miljoforum/m_a
lge/img/alexandrium.gif
about 30
microns or
.03 mm
photo from www.whoi.edu/redtide/labweb/projects.html
Dinoflagellates
The dinoflagellates are a large group of marine phytoplankton, but they are
common in fresh water habitats as well. Dinoflagellates make up the largest
group of algae aside from the diatoms. Being primary producers they begin
the aquatic food chain as they make their food using the sun through
photosysnthesis.
single cell
steers the cell
flagella
pushes the cell
Most dinoflagellates are very tiny single cells with two whip-like tails called
flagella. One of these flagella extends towards the back end while the other
forms a circle around the cell. The flagella move the cell, and can cause a
whirling motion, which the name dinoflagellate comes from... (Greek dinos,
whirling). Dinoflagellates have a complex cell covering that comes in various
shapes and arrangements... some with spikes and spines, such as in Ceratium
species. The cells contain chlorophyll as well as various other plant pigments
giving them a reddish brown color. Dinoflagellates sometimes bloom in
concentrations of more than a million cells in a milliliter of water.
Some species like Alexandrium produce neurotoxins... (nerve poisons) which
in large quantities kill fish and build up in algae eaters such as clams, oysters,
and mussels . People who eat infected shellfish may get a disease called
PARALYTIC SHELLFISH POISONING or “PSP” which can be fatal by shutting
down the nerves which direct muscles to work... thus paralyzing the muscles.
This bloom is called a red tide, from the color the bloom may give to the
water. Some colorless dinoflagellates may also form toxic blooms, such as
Pfiesteria. Not all dinoflagellate blooms are dangerous. Bluish flickers in ocean
water at night often come from blooms of bioluminescent dinoflagellates,
which give off short flashes of light when disturbed.
Alexandrium - a species of dinoflagellate which causes red tide.. see photos on p.1.
Aquatic- having to do with water
Bioluminescent -
“Bio” (meaning from life) “lumin” (meaning light)
when living things have the ability to give off light as in fireflies
Bloom - an event where plankton multiply rapidly resulting in large numbers or
high concentrations of plankton in the water
Chlorophyll - a green chemical in “plant” or algae cells which takes in the Sun’s
light for photosynthesis
Ceratium - a species of dinoflagellate whose cell wall has long spines..see p.1.
Dinoflagellates - red-brown phytoplankton whose cells have two flagella
Diatoms- golden brown phytoplankton whose tiny cells have clear walls of glass
... the most comon form of phytoplankton...and responsible for
most of our oxygen through photosynthesis
Flagella - whip-like tails in single cells used to move them through water
Neurotoxin - from “neuro” (nerve) “toxin” (poison) a poison that prevents nerves
from working properly
Photosynthesis - from “photo” (light) and “synthesis” (to make) process in
plants and algae which make their food from water and carbon dioxide
using the Sun’s energy... AND giving off oxygen as by-product
Plant pigment - a colored chemical (green, orange, yellow, red, or brown) in “plant”
or algae cells which takes in the Sun’s light for photosynthesis
Phytoplankton - plants or algae which drift in the current
Producers - plants or algae which make or “produce” food using photosynthesis
to begin the food chain
Red Tide - a harmful bloom of algae or phytoplankton... normally dinoflagellates.