Transcript A cyanobacteria bloom

Phytoplankton
MARE 444
Lecture 2
Phytoplankton
the majority of the plants in the ocean are
planktonic unicellular algae called
phytoplankton.
some can be caught be nets, others can only
be collected by filtering or centrifugation
(e.g., nano- and picoplankton).
Phytoplankton
Group
Diatoms
Dinoflagellates
Microflagellates
Picoplankton
Cyanobacteria
Prochlorococcus
Eukaryotic Pico
Phycological Terminology
Bacilliariophyceae
Dinophyceae
Haptophyta, Prymnesiophyta,
Chrysomonadales,
Cryptomonadales
Photoautotrophs < 2μm
Cyanophyta, photosynth bact.
Photosynth bacteria
Very small, struct. advanced
Phytoplankton
Vital role in marine food chain
4000 species of phytoplankton have been
described, new species are continually being
described
At least 13 classes of marine phytoplankton
are distinguished, representing a wide variety
of organisms
Phytoplankton
Phytoplankton account for about half of global
primary production
Types of Phytoplankton
Bacteria and cyanobacteria
Diatoms
Dinoflagellates
Others
Photosynthetic Bacteria and
Cyanobacteria
Photosynthetic Bacteria
Prokaryotic (Kingdom Monera)
Contain bacterial chlorophyll (different from
the other chlorophyll molecules)
Cyanobacteria
Prokaryotic (Kingdom Monera)
Contain chlorophyll-a (like eukaryotic
autotrophs)
Cyanobacteria
Important primary producers
Small size (1-2μm)- large SAV ratio
Sink or rise very slowly
Maximize nutrient absorption
Reduces grazing loss
Cyanobacteria
Distribution
A cyanobacteria bloom
The Diatoms
Microalgae
Diatom Cellular Structure
(chrysolaminarin)
(chlorophyll a and c,
fucoxanthin, etc)
The Diatoms
Planktonic diatoms
Silica shell and lack of flagella = sinking
diatoms evolved various strategies to counter
sinking
chains
spines
oil droplets
ionic regulation - internal ion concentration
is lower than external seawater =
reduction in density
Diatoms with elaborate
spines and processes
Functions:
The Dinoflagellates
Dinoflagellate Characteristics
Typically 2 flagella
Large nucleus (looks like a fingerprint)
Chlorophylls a and c
Accessory pigments (ß-carotene, peridinin,
xanthophylls)
Food reserve is starch
Dinoflagellate Characteristics
Some have:
Dinoflagellate Characteristics
Some are autotrophic, others are auxotrophic,
others are mixotrophic, others are
heterotrophic
Dinoflagellate Taxonomy
Armored
plates (numbers, shapes)
Naked
size and shape
cingular position, displacement, and overhang
sulcal placement and intrusion
presence/shape of apical groove
Dinoflagellate Ecology
Dinos tend to occur in the summer and early
fall when nutrients are more depleted and
seas are calmer
Microflagellates
Some (e.g., coccolithophorids) are very
common
Coccolithophores
Unicell containing a haptonema between two
smooth flagella
Haptonema - a coiled appendage that is used
for feeding and sensory purposes
Chlorophylls a, c1, and c2, carotenoids
Chrysolaminarin
Coccolithophores
Single regular calcareous plates
Prokaryotic Picoplankton
Prochlrophyta
Often most abundant phtoplankton in
oligotrophic, tropical waters
Have traits in common with several
taxonomic groups
bacteria, cyanobacteria, green algae
Eukaryotic Picoplankton
Typically green algae (Chlorophyta)
Contain chlorophylls a and b, carotenoids,
xanthophylls
Starch is the food reserve
1, 2, 4, or 8 flagella