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Plankton-Plankton are almost always at the bottom of the food chain in any marine environment, making them possibly the most important group.
-The word “plankton” isn’t necessarily a technical science term, it is a general word to describe small organisms with no control over their long-term movements.
-There are several groups and types of planktonic organisms.
http://science.discovery.com/videos/brink-package-algae-to-oil.html
PhytoplanktonDiatoms – phylum bacillariophyta
-Anywhere from 5,000 – 50,000 species estimated.
-More than 1 million diatoms can be created from 1 diatom in just 2 weeks.
-Make up 25% of photosynthetic biomass on Earth.
*Bilateral or Radial symmetry*Frustule - two-part silica skeleton. One layer sits outside of the other,
sort of like the lid of a petri dish
*Secretes a “mucous” through the raphe, long slit down the center of a diatom
raphe
PhytoplanktonDinoflagellates - Dinophyta
*2nd largest group of photosynthetic algae, behind
diatoms.
*Very few of them are heterotrophic parasites in fish.
-Small movements by means of flagella, protein appendages
that flip back and forth
-Red tide phenomenon is caused by dinoflagellates. Its an
overgrowth caused by excessive nutrients, water is reddish
brown due to tons of dinoflagellates in water. (up to 20 million
per liter) pictures on next slide.
-Many species are bioluminescent when disturbed.“……it is not the property of fire alone to give light;…small
drops of the water, struck off by the motion of the oars in
rowing, seem sparkling and luminous.”
Francis Bacon, 1605
Plankton - Red Tides-Large amounts of dinoflagellates turn the water reddish-brown, and make it
poisonous to humans and other organisms who live in the water.
Red tide off coast of Washington State
Off the coast of California
-These produce high amounts of potentially deadly neurotoxins.
Phytoplankton
*Mutualism between coral and
dinoflagellates
PhytoplanktonGreen Algae – Phylum Chlorophyta
*When you typically think of seaweed,
this is what you are actually thinking of.
*Photosynthetic, mainly multicellular in
marine ecosystems.
*Scientists believe that land plants may
have evolved from green algae due to
having similar types of cholorphyll.
*Produce cellulose (makes cells rigid
and hard).
*Different in that green algae lack roots
and transport structures (xylem and
phloem).
-Some species also have mutualistic relationships with coral and other cnidarians
(jellies).
PhytoplanktonRed Algae – Phylum Rhodophyta
*Similar to green algae, except they have no
cellulose, but some do secrete calcium
carbonate.
*Do NOT produce the same types of
chlorophyll as land plants and green algae.
*Some secrete calcium carbonate (act like
cement in a brick wall).
*Phycoerythrins – red pigments produced by red algae. NO OTHER
EUKARYOTE contains these pigments.
***They can live in deeper water because they absorb blue light,
which travels further than any other color on the spectrum.
PhytoplanktonBrown Algae – Phylum Phaeophyta
*Most complex structure of all types of
marine algae.
*Can have holdfasts (roots), blades
(leaves), stipes (stalks), pneumatocysts
(air-filled chambers to keep near light).
*Kelp can reach the surface from nearly
80 feet deep (grow almost a foot a day).
Sargasso Sea (Center of North Atlantic) –
named because of so much floating brown
algae (sargassum is a genus of brown
algae).
Amoeba/Paramecium
Amoeba – eukaryotes, engulf their
food using phagocytosis
Paramecium – eukaryotes, move
using cilia, tiny hairs. Hairs also
push food into mouth-like opening.
ZooplanktonPhylum Arthropoda
Copepod - plankton from
Spongebob
Daphnia – water fleas
(look like pregnant
birds)
Krill – closely related to
shrimp, one of the most
abundant animals in the
sea. Ostracod – swim in circles
with long appendages
Phylum cnidaria – hydra,
smaller sea anemone
Planaria – flat
worms, 2 eyespots.
Nematodes – Phylum Nematoda-These are extremophiles, meaning they can
survive in extreme environments.
-They can live in incredibly hot or cold habitats and
can survive on almost no food for weeks at a time.
-Tens of thousands of species have been identified,
most of which are parasitic.
Nematode digestive infection
Why are these all
so IMPORTANT?BOTTOM OF THE FOOD CHAIN!!!!!!!!!!!!!