marine phytoplankton Flashcards
primary production
The process where organisms turn inorganic matter into biomass using solar energy
Gross Primary Production is all the energy primary producers create in a given time
Net Primary Production is what is left after algal respiration
marine phytoplankton - o2 in atmosphere
Marine phytoplankton produce ~50 % of the oxygen in the atmosphere
light in the ocean
Direct reflection as soon as light hits the surface
High absorbtion by water (especially long wave, red light)
Scattering of light (especially short wave, blue light)
Photic zone
In the photic zone photosynthetic organisms can get enough light for their photosynthesis. It’s usually where 1% of light intensity of the surface is still available, ~200 m deep if very clear.
phytoplankton net contents
Typical phytoplankton net contents dominated by ‘large’ dinoflagellate and diatom cells.
200 micron dinoflagellate surrounded by many picoplankton cells (0.2 – 2 microns). These tiny cells account for 79 % of photosynthesis in the tropics, produce oxygen, fix nitrogen, make vitamins, take up CO2. The cyanobacterial genus Prochlorococcus is probably the most abundant photosynthetic organism on Earth.
main phytoplankton groups
- cyanobacteria
- diatom
- dinoflagellate
- green algae
- coccolithophore
tree of life
Genome analyses show that much of Earth’s Biodiversity is Bacteria (~76 phyla). One of those phyla is the Cyanobacteria.
Half of bacterial diversity is thought to be still waiting to be discovered. Usual methods such as culturing or 16sRNA sequencing does not reveal them.
The Archaea are another major group of life on Earth (~28 phyla), first noted in extreme environments like deep-sea hydrothermal vents.
Cyanobacteria (prokaryotes)
3.5 billion years old and the reason our atmosphere became oxygenated
About 2000 species
Thylakoides have chl a, carotenoids, phycobilin (some with phycoerythrin)
Carboxysomes are protein complexes that help fix CO2
Storage product: Glycogen
Cells often grow in colonies
Origin of plants through endosymbiosis
nitrogen fixation - cyanobacteria
In certain filamentous cyanobacteria N2 fixation occurs in specialised cells called heterocysts where the oxygen sensitive enzyme Nitrogenase fixes nitrogen.
Chromalveolata (eukaryote)
Heterokontophyta such as brown algae and diatoms and Haptophyta such as coccolithophores
Archaeplastida (eukaryotes)
land plants, green algae, red algae
green algae
Chlorophyta is a polyphyletic group
Pigments: Chlorophyll a, b, beta-carotenoids, and xanthophylls
Starch storage
The ancestors of land plants
coccolithophores
Main oceanic calcium carbonate (CaCO3) producers
Produce Dimethylsulfoniopropionate (DMSP) which works as cloud condensation nuclei
Phylum Haptophyta
Two anterior flagella and a haptoneme
Exoskeleton made out of calcite
Pigments: chl a, chl c, carotenes and xanthophylls
Store acid polysaccharids, beta glucan, alkenoids
diatoms
Phylum Ochrophyta, ~12,000 named species
Mainly built up of silica (Si)
Overlapping shells called frustules
Pigments: Chl a, Chl c, beta-caroten, fucoxanthin, diato- and diadinoxanthin
Storage Products: lipids, chrysolaminarin
2 main groups : pennate and centric
Diatoms tend to get smaller when they divide vegetatively, the large upper frustule is the epitheca, the smaller lower frustule is the hypotheca
dinoflagellates
Phylum Dinophyta, ~ 1700 marine species
Can obtain energy through photosynthesis or phagotrophism
Chl a and Chl c2. plus xanthophylls that give them their golden brown colour
Store starch and oil
Endosymbionts called zooxanthellae, e.g. in corals, nudibranchs, giant clams.
Big nucleus, filling 25-35% of the cell
Cellulose in plasmamembrane gives them a rigid structure. In plate form the structures are called theca
Most photosynthetic dinoflagellates have light sensitive organelles
Dinoflagellates swim in a distinct whirling pattern due to two flagella
Some species have nematocysts or trichocysts, ejectile organelles used for protection or excretion
