plankton Flashcards
how to sample plankton? (5)
Jar/Bucket: easy, specific plankton, cheap, represents general concentration of the plankton. Not efficient, not concentrated, only goes as deep as your arm.
Nets: going deeper, more concentrated, easy to use. Expensive, planning to drag at different depths.
Trap: only captures plankton from a certain depth, easy to figure out plankton density. Takes a long time, pollution, resource allocation, mesh quality, non selective based on size.
Bottles/tubes: Simple, discrete depth, looks cool, representative concentration. Expensive, small sample size.
Pump: Very concentrated amount of plankton, easy to use. Expensive, time consuming, resource allocation.
what’s the structure of diatoms?
Unicellular
No flagella - cannot move themselves
Skeleton made of glass (silica): frustule
of 2 valves (epitheca & hypotheca) with pores
Centric (and pennate which are usually benthic)
May form chains
May have spines
how do diatoms reproduce?
Asexual by cell division followed by new hypotheca formation
This method reduces frustule size
Sexual reproduction occurs to
restore frustule size
Amount of silica in seawater limits
rate of reproduction in diatoms
what is the diatomaceous earth used for?
- Pesticide
- Absorbant
- Facial exfoliant
- Shoe deodorizer
- Scouring powder
- Preserving food
- Health
- Filtering
what’s the structure of dinoflagellates?
Unicellular
Cellulose in cell walls
Two flagella (longitudinal and transverse)- whirlers bioluminescence- noctiluca
what’s the structure of coccolithophores?
Unicellular
Two flagella at one end of cell
Covered in calcium carbonate disks
- found on the white cliffs of Dover:
what adaptations do phytoplankton have?
Oil droplets for buoyancy in diatoms
(beach foam)
Spines e.g. Chaetoceros
Chain formation e.g. Chaetoceros
Flagella for movement e.g. Noctiluca,
Pyramimonas, coccolithophores
Ceratium grow fingers to catch more
light and for buoyancy
Bioluminescence
e.g. Noctiluca
what are the factors that affect phytoplankton?
Light, temperature and nutrients affect
primary production (=photosynthesis)
by phytoplankton
Lack of nutrients (especially iron)
reduces primary production and
therefore the presence of phytoplankton
what’s primary productivity?
the synthesis of new organic material from inorganic
molecules such as H2O and CO2
how do algal blooms affect the marine ecosystem
Oxygen depletion 🡪 dead zones
Block light to macroalgae
Clog fish gills
what are the 3 phases of biological carbon pump?
Photosynthesis /primary production by
phytoplankton
Sinking / marine snow
Deep sequestration of carbon
what are the two types of zooplankton?
Holoplankton and meroplankton
Holoplankton - spend their whole life as plankton e.g. comb jellies, copepods
Meroplankton - only part of their life cycle is spent in the plankton before they metamorphose and live benthically or as nekton e.g. sea urchin larvae,
barnacle larvae, crab larvae
what are the physical adaptations of zooplankton?
Transparency e.g. jellies, chaetognaths
Red-coloured e.g. deep-sea jellies
Gelatinous e.g. jellyfish, larvaceans, comb
jellies
Increased surface area
- with spines e.g. porcelain crab larvae
- by flattening body e.g. amphipods
Big eyes e.g. amphipods, cladocerans
what are the behavioral adaptations of zooplankton?
Vertical migration e.g. krill, copepods
Bioluminescence
what’s microbial loop?
Bacterioplankton use dissolved organic material (DOM) – wastes of zooplankton and phytoplankton
Bacteria then become the food of single-celled protozoans
Which are then eaten by zooplankton – closing the loop
