What does it mean to be planktonic? Why is the community so important to the marine ecosystem?
Floaters in the photic zone. Primary producers and consumers. Energy in food chain. No ability to travel along with a purpose.
Why are diatoms a good food source for other organisms?
Because since they are primary producers, they contain the most energy in the food chain (as compared to tertiary consumers etc.)
glassy cell wall: silicon; organic & mineral components; organic: carbohydrtae pectin with silica (silicon dioxide) (accounts for 95% of diatom weight); each half = valve (fit together like a shoe box); rough surface
What is special about the silica shell of a diatom?
It does not readily break down; they sink to the bottom of the ocean to form a layer - sedimentary rock or diatomaceous rock
What do we use diatom silica shells for?
Because they aggregate and form diatomaceous rock, it is porous and ergo used to filter pool water, beer, and champagne; used as mild abrasive in silver polish and toothpaste; sound product and insulation product
How do coccoliths differ from the frustules of diatoms?
composed of disk shaped scales; calcium carbonate
How do coccolithophores get their energy?
From the sun.
Where might you find a high abundance of coccolithophores?
How can looking at a core sample of diatom and coccolithophore shells give insight into what surface conditions were like in the past?
Because they are planktonic organims, they reside in the pelagic zone and then sink to the bottom. Due to their shells being made of calcium carbonate, which decomposes in the prescence of a high acidity, one could tell the rate of decomposition. It gives insight to calcification and the amount of CO2 in the atmosphere. It also tells the temperature (i.e. if waters were colder, there would be less)
How many flagella do dinoflagellates have?
How do dinoflagellates get their nutrition?
Sun: photosynthesis; engulfing nutrients: phagotrophy
What roles do dinoflagellates play in the marine ecosystem?
they are phytoplankton - food source; algal blooms - psp; tropics: abundant; symbionts of jellies, corals, and molluscs
What characteristic defines the ciliates?
cilia - membranelles; cytosome: site for phagocytosis; 2 nuclei: micro (one diploid set), macro (many copies of genes for metabolism)
What are the ecological roles of ciliates?
Why are choanoflagellates important?
marine & freshwater; single & colonial; found in corals and sponges; like animals; highly efficient in consumption of bacteria
What is the structure of a choanoflagellate?
single flagellum surrounded by a funnel shaped base (collar of tentacle-like projections - microvilli)
How do choanflagellates obtain nutrients?
Movement of microvilli make current that draws H2O through
What are actinopods? (Radiolarians)
long, needle-like pseudopods
Why are actinopods important? (Radiolarians)
capture food; decrease sinking rate - controls buoyancy
How do Radiolarians get their nutrition?
from actinopods; feed on phytoplankton and zoa plankton; large radiolarians: copepods
Why might there be a migration of zoa plankton throughout the day?
to feed; so that they are not eaten by larger organisms in the photic zone during the day; so that they do not get too much sun
remain in a planktonic stage throught their lives; ex: diatoms & dinoflagellates
only planktonic organism during larval stage
small organisms that drift and float freely in the waters of the photic zone (marine & freshwater)
fresh/salt; photoautotrophic; 1/3 of O2; diverse; monitor environmental conditions; silica dioxide
flagellum; marine; photosynthesis; food source for organisms; some species produce neurotoxins - red tide
the aggregate of actively swimming animals in a body of water ranging from microscopic organisms to whales
benthic: sea floor; photic: where sun reaches; pelagic: open ocean
phtyplankton; calcium carbonate; indicator species; rapid growth = milky white ocean
single-celled; silica shell; capture food by extending parts of body through holes in the shell; can be preserved in sediment like diatoms
How do you get plankton specimens?
Seine or plankton tow
predatory; uni-cellular; flagellum, microvilli, cell body
production of light without producing heat; simple enzymatic reaction:
enzyme + substrate + O2 --> light
hypothesized: evolved as a detoxification agents; see diagram with luciferin; kinds: bacterial, extracellular, intracellular
radially symmetric frustules
bilaterally symmetric frustules