Paleoceanography summary exam II
Spatial and temporal variability → be careful when extrapolating from sediment core to whole
ocean. Differences in paleogeography and types of organisms (evolution)
CaCO3 = calcium carbonate (solid phase)
HCO3- = bicarbonate (dissolved)
CO32- = carbonate (dissolved)
H2CO3 = carbonic acid
NO3- = nitrate
NH3 = ammonium
CaSiO3 = silicate bedrock
H4SiO4 = Si(OH)4 = dissolved silica = silicic acid
SiO2nH2O = Biogenic silica = biogenic opal
Si = silicate (element)
Silicate = compound/ion containing SiO4
Organic matter production
- Production in the surface ocean
- Sinking flux of OM into deeper waters
- Dissolved OM: leaks from organisms, acts as a solute
- Photosynthesis in Euphotic zone = layer where light is present
- All phytoplankton need N and P
In sea water: ammonium (low C, converts to nitrate) and nitrate
Depth profiles
- Low but important concentrations
- Low in surface waters → there they are taken up
- Higher in intermediate→ flux of OM into deep water, nutrients released again
- Less release in the deepest areas
Biological pump = biological processes bringing carbon to the ocean’s interior
,Degradation of OM = remineralization and regeneration
Euphotic zone:
- inorganic carbon → OM : nutrient consumption and oxygen production.
- OM degrades below euphotic zone, little OM makes it to the sea floor
- Some OM recycled in euphotic, some settles (by gravity) to ocean interior
Ocean’s interior:
- recycled in thermocline and deep waters : oxygen consumption and CO2
- Some buried as OM, some released as CO2 in deep waters.
OM recycling
Average Marine OM
Redfield ratio 106:16:1
Redfield composition (CH2O)106(NH3)16H3PO4
Phytoplankton build in N and P in OM at a constant ratio
This is average, can vary depending on species and environmental conditions
Redfield ratio of sea water
Stoichiometry of OM production
Stoichiometry = quantitative relationship between elements in reactions or materials
, - Including nutrients, more water is taken up and more oxygen is produced
- Conversion of nitrate into ammonia → produces oxygen.
- OM more complex than CH2O → need less water and produce more oxygen when OM is
formed.
- True average: Ratios differ per carbohydrate → lipids and proteins have different ratios
Know simplified by heart, complicated ones not.
Phytoplankton = micro-organisms capable of photosynthesis
Primary producers → fix carbon.
Not secondary producers = heterotrophs (produce OM based on uptake of OM)
Separation → metabolism
- Autotrophs = harvest light or chemical energy to produce OM (and release oxygen)
- Photo(auto)trophs = use light
- Chemoautotrophs = use chemical energy (e.g. sulphite and oxidize)
Separation → size
>20k species
- Pico : 0.2-2 μm
- Nano : 2-20 μm
- Micro : 20-200 μm
Size matters:
- Living
o Small: few nutrients. Open gyres. Oligotrophic ocean. Warm water. Low production.
o Nano and micro: high nutrient availability, high production, coastal zone, upwelling
- Sinking speed
o Larger : sink out of euphotic zone more easily, less recycling
- Eat:
o Smaller → more easy to eat
Picophytoplankton
- Very small, important, efficient nutrient uptake
- Live at low nutrient concentrations, open ocean, cannot fix nitrogen from atmosphere
, - Unicellular autotrophic cyanobacteria: Synechococcus and Prochlorococcus
Larger algae → need to know these!!!! (nano and micro, large, inefficient nutrient uptake)
responsible for much OM production
Diatoms
- Silicate shield: SiO2
- First to bloom
Coccolithophorids
- CaCO3 shields
- Reduced light, later blooms, warmer waters
Dinoflagellates
- Cellulose (theca)
- Motile, coastal areas, red tides, mixo and heterotrophs (no theca)
Phaeocystis
- Massive blooms in e.g. north sea
- Produce dimethyl sulphide (DMS) → gas released in atmosphere.
- Climate impact → forming cloud condensation nuclei
- Foam on beaches upon decay of the algae after a bloom
Cyanobacteria: Trichodesmium
- Lives in solitude or colonies
- Diazotroph: Fixes N from atmosphere and convert to NH3, does not need nitrate
- Nutrient-depleted environments in open ocean: important in (sub)tropical regions
Zooplankton grazing
- Impact amount of phytoplankton
- Waste products → droppings can sink → important for biological pump
- Release of ammonium
- Prefer nitrate instead of ammonium → less energy (no conversion needed). Help recycling of
nutrients
Pteropods : aragonite (CaCO3)
Foraminifera : calcite (CaCO3)
Ciliates : eat pico
Copepods : eat micro (couple of mm large)
Factors governing OM production
P = R B f (nutrients, CO2) f (light)
Spatial and temporal variability → be careful when extrapolating from sediment core to whole
ocean. Differences in paleogeography and types of organisms (evolution)
CaCO3 = calcium carbonate (solid phase)
HCO3- = bicarbonate (dissolved)
CO32- = carbonate (dissolved)
H2CO3 = carbonic acid
NO3- = nitrate
NH3 = ammonium
CaSiO3 = silicate bedrock
H4SiO4 = Si(OH)4 = dissolved silica = silicic acid
SiO2nH2O = Biogenic silica = biogenic opal
Si = silicate (element)
Silicate = compound/ion containing SiO4
Organic matter production
- Production in the surface ocean
- Sinking flux of OM into deeper waters
- Dissolved OM: leaks from organisms, acts as a solute
- Photosynthesis in Euphotic zone = layer where light is present
- All phytoplankton need N and P
In sea water: ammonium (low C, converts to nitrate) and nitrate
Depth profiles
- Low but important concentrations
- Low in surface waters → there they are taken up
- Higher in intermediate→ flux of OM into deep water, nutrients released again
- Less release in the deepest areas
Biological pump = biological processes bringing carbon to the ocean’s interior
,Degradation of OM = remineralization and regeneration
Euphotic zone:
- inorganic carbon → OM : nutrient consumption and oxygen production.
- OM degrades below euphotic zone, little OM makes it to the sea floor
- Some OM recycled in euphotic, some settles (by gravity) to ocean interior
Ocean’s interior:
- recycled in thermocline and deep waters : oxygen consumption and CO2
- Some buried as OM, some released as CO2 in deep waters.
OM recycling
Average Marine OM
Redfield ratio 106:16:1
Redfield composition (CH2O)106(NH3)16H3PO4
Phytoplankton build in N and P in OM at a constant ratio
This is average, can vary depending on species and environmental conditions
Redfield ratio of sea water
Stoichiometry of OM production
Stoichiometry = quantitative relationship between elements in reactions or materials
, - Including nutrients, more water is taken up and more oxygen is produced
- Conversion of nitrate into ammonia → produces oxygen.
- OM more complex than CH2O → need less water and produce more oxygen when OM is
formed.
- True average: Ratios differ per carbohydrate → lipids and proteins have different ratios
Know simplified by heart, complicated ones not.
Phytoplankton = micro-organisms capable of photosynthesis
Primary producers → fix carbon.
Not secondary producers = heterotrophs (produce OM based on uptake of OM)
Separation → metabolism
- Autotrophs = harvest light or chemical energy to produce OM (and release oxygen)
- Photo(auto)trophs = use light
- Chemoautotrophs = use chemical energy (e.g. sulphite and oxidize)
Separation → size
>20k species
- Pico : 0.2-2 μm
- Nano : 2-20 μm
- Micro : 20-200 μm
Size matters:
- Living
o Small: few nutrients. Open gyres. Oligotrophic ocean. Warm water. Low production.
o Nano and micro: high nutrient availability, high production, coastal zone, upwelling
- Sinking speed
o Larger : sink out of euphotic zone more easily, less recycling
- Eat:
o Smaller → more easy to eat
Picophytoplankton
- Very small, important, efficient nutrient uptake
- Live at low nutrient concentrations, open ocean, cannot fix nitrogen from atmosphere
, - Unicellular autotrophic cyanobacteria: Synechococcus and Prochlorococcus
Larger algae → need to know these!!!! (nano and micro, large, inefficient nutrient uptake)
responsible for much OM production
Diatoms
- Silicate shield: SiO2
- First to bloom
Coccolithophorids
- CaCO3 shields
- Reduced light, later blooms, warmer waters
Dinoflagellates
- Cellulose (theca)
- Motile, coastal areas, red tides, mixo and heterotrophs (no theca)
Phaeocystis
- Massive blooms in e.g. north sea
- Produce dimethyl sulphide (DMS) → gas released in atmosphere.
- Climate impact → forming cloud condensation nuclei
- Foam on beaches upon decay of the algae after a bloom
Cyanobacteria: Trichodesmium
- Lives in solitude or colonies
- Diazotroph: Fixes N from atmosphere and convert to NH3, does not need nitrate
- Nutrient-depleted environments in open ocean: important in (sub)tropical regions
Zooplankton grazing
- Impact amount of phytoplankton
- Waste products → droppings can sink → important for biological pump
- Release of ammonium
- Prefer nitrate instead of ammonium → less energy (no conversion needed). Help recycling of
nutrients
Pteropods : aragonite (CaCO3)
Foraminifera : calcite (CaCO3)
Ciliates : eat pico
Copepods : eat micro (couple of mm large)
Factors governing OM production
P = R B f (nutrients, CO2) f (light)
