| how are nutrients distributed in the vertical in arctic vs subarctic | in subarctic nutrients are quickly depleeted and are therefor often found depper than in arctic where they are deepleted slower |
| how are nutrients distributed in the vertical in arctic vs subarctic | in subarctic nutrients are quickly depleeted and are therefor often found depper than in arctic where they are deepleted slower |
| how are nutrients distributed in the vertical in arctic vs subarctic | in subarctic nutrients are quickly depleeted and are therefor often found depper than in arctic where they are deepleted slower |
| Sig noget klogt om freshwater vs seawater i forhold til densitet | Check the statistics |
| Stratification i forskellige årstider | boom |
| Hvad er irradiance?
Hvordan aftager lyset igennem vandet (Beers law)?
Hvor dyb er den fotiske zone? | irradiance - micromol fotoner *m^-2 *s^-1
Lys - aftagelse er eksponentiel. Beers law er på slide.
Fotiske zone - 1% af overfladelys. |
| Hvad ser man med sechidiscen og hvordan kan man udregne K (attenuation koefficient) og euphotic zone? | K (attenuation koefficient) ≈ 1.7/sechi depth
Euphotic zone ≈ 2,5 * sechi depth |
| hvad er forel-ule scale? | Se billedet |
| bare lige hurtigt om photosyntesen | Light reactions happen in the chlorofyl and feeds energy into the calvin cycle
Phophate and nitrogen are the most important nutrients |
| What is the epipelagic area? | Top 200m |
| What gas is the most common in the ocean?
What is DON?
How does phosphor occur?
Who are often iron limited?
What are macro and micronutrients? | Nitrogen is most common as gas in the oceon (ca 90%) but only cyanobakterie kan use it this way.
We call everything below what we can filter disolved organic nitrogen (DON) so even small cells fit in this category
Phosphor occors as phosphate or dissovled organic phosphuros.
Iron is also very important in phytoplankton cells.
Nitrogen, phosphor and silicon are called macronutrients because they occur in large amounts in the oceon.
Micronutrients: < 0,05% of biomass in the cell: Fe, Mg, Zn etc |
| What is Liebigs' law? | The law of limiting factors?
Nitrogen is often limiting in oceans for phytoplankton and phosphorus is often limiting in freshwater.
Silicons are limiting in oceons for diatoms because they have silicon housing
Fe is limiting in antarctica.
Nutrients in smallest relative supply will limit growth.
INcreasing nutrients often has limited effect but decreasement has big effect. |
| Nitrogen cycle what can you say?
What is the F ratio and what is it used for? | In spring in oceons the water collom is very well mixed, so the nitrate from the bottom water can come up again. Can be used by phytoplankton which are eaten by for instance copopods and so on.
But with strong stratisfication nitrate can not be used in upper layers. Bakteria in the upper layer are converting parts from copopods to amonium which is used by phytoplankton.
In the spring the primary production is most based on amonium. (regenerated primary production)
The F ratio: how much of the primary production is based on new production. The F ration can tell us where we are in the seasonal development.
Upwelling leads to nutrients coming up from the buttom – a lot of new production.
In oligotrphic areas – mostlly based on regenerated production
A rule of thumb is when there is a lot of regenerated nitrogen production is pretty low. |
| What are HNLC areas? | High Nutrient Low Chlorofyl. Areas with high nutrients with low clorofyl are called HNLC areas. Seems its because og Fe limitation. |
| Who loves silicate?
When is silicate in upper layers low | 1 - diatoms
2 - This is because of diatoms. They take cilicons into the cells and silico in the upper layers is therefor lower. |
| What is the red field ratio?
What are the two exceptions? | Pretty much the same ratio for all C: 106: N: 16: P: 1
exeptions: in anoxic zones where nitrogen is used to destruct organic matter.
Also exception in spring bloom
This doesn’t apply to silicate because only diatoms use silicate to build houses. |
| What are the general size scale for:
Pico-
Nano-
Micro-
Meso-
Macro-plankton | skrt |
| What are the two main groups of phytoplankton? | Dinoflagelates and diatoms |
| What can you say about diatoms?
When are they commenly found? | Have silicate shell:
Are most common in spring bloom because of high growth rate. |
| Two shapes of diatoms? | Pennate - aflang
Centric - rund |
| How do diatoms grow? | Diatoms are mostly dividing and therefor get smaller and smaller:
Most growth is through vegetative growth – asexual.
When they reach minimum size they do sexual reproduction.
The vegetative growth makes an exponential curve
Growth rate is very important for succes. In optimal conditions the ones with highest growth rates outcompedes the others. So in spring diatoms outcompete dinoflagelates but dinoflagelates are better with limied nutriants and therefor win later on |
| General about dinoflagelates | Dinoflagelates:
Most are small
A lot can be both autotrof and heterotrof and mixotrof.
Can have a cellulose shell.
They are most common after the spring bloom.
Some can be bioluminescent.
can pruduce toxins as defense for predators |
| What are other ways of characterising phytoplankton? | size
habitat
way of living |
| Different pigments found in phytoplankton
How are they meassured | all have chlorofyl a
diatoms have phucoxanthin that indicates they are related to brown algee
They are meassured by HPLC High Performance Lipid Chromatography |
| what is a phytoplankton bloom and where and when do they happen? | We find blooms where there is elevated concentrations of nutrients
They typically happen in spring but can also occur in smaller size in autum. |
| What are the strategies of phytoplakton on high latitudes in winter? | We don’t know a lot about them. But they overvinter.
When the growing season ends, they retract the organic matter into the middle and goes into a resting stage to survive withuot light and nutrients. A lot of them die during this period. The ones that survive are transported back up during spring. |
| What is the aarms race in relation to phytoplankton and...? | Many phytoplaton spicies have developed toxins to avoid grazing.
The arms race – copopods then evolve to tolorate toxins. |
| what physical and biological factors influence phytoplankton? | Se billedet |
| How is the stratisfication in norway seasonally? Closer to temperate or polar? | In norway the picture looks more like the temperate areas:
This is because of oceon circulation, we get warm water from the golf strem/ atlantic curve.
Most of the oceanographic feature (except for instance light) looks more like a temperate region than a polar.
The later the season the shallower the mixing layer. |
| Effect of sea ice on statification? | Top one is arctic water influenced by ice. Here the stratisfication starts earlier because of the ice melting adding freshwater and the cold water and adds difference in temperature |
| What can you say about stratification and spring bloom? | check the statistics |
| What is light compensation point?
What is the critical depth? | Compensation (light makes photosynthesis = respiration) point
critical depth (total algee production = total algee respiration)
This means that critical depth is deeper than the compensation point if you think about it |
| When does the spring bloom start (Sverdrups' paradigm)? | Okay så critical depth fortæller jo den dybde hvor den samlede algerespiration = den samlede algeproduktion. Vi skal huske algerne bare flyder random rundt.
Hvis critical depth > mixing depth kan spring bloom begynde. Mixing går ikke ligeså dybt ned som det punkt hvor respiration overhaler produktion.
Til gengæld hvis mixing depth > critical depth vil den samlede respiration være større end den samlede produktion og algerne forsvinder. |
| When are we not able to see phytoplankton biomass from a satelite? | When the top nutrient layers have been depleted so all the phytoplankton are down close to the pycnocline |
| What is coastal upwelling? | Coastal upwelling occors when the wind transports (transport) water away from the coast so nutrient rich water from deeper oceons come to the cost.
In southern hemisphere it happens when wind travels from right angels towards the left and oppisite on nothern hemispheres |
| Name an alternative explenation to svendrups paradigm | The disturbance-recovery hypothesis
basicly means that grazzers control the phytoplankton concentration
Zoo plankton are a bit later than phytoplankton and control the phytoplankton population
important to remember that dinoflagelates can also be grazzers on same size and down |
| In temperate areas:
how is the annual phytoplankton, light, nutrients, and zooplankton. Explain wy | Boom check the picture fam |
| Spring bloom | Two important factors:
Light increase and nutrients.
Grazing is not very important for the inition of the bloom but important for the decline.
In the high arctic the bloom is late and short but a LOT of phytoplankton (ice melts away andd sudendly there is light and the melted water makes stratification) and in more temperate areas it is less strong but over longer periods of time. |
| What can you say about ice algee | Ice algee are very important in arctic ecosystems and can have high biomass
These are actually chain building diatoms that make them appear as macro algee.
They utalize how much light comes through the ice.
relative importance of ice algee increase with latitude |
| What can you say about biomass vs production in different seasons? | In summer biomass is low but production is high. This is because of grazers. The production is very high but grazers keep the biomass down.
F ratio: amount of production based on new production. It will be very low here because there is a lot of grazers and the nutrients are being reused. grazers eat photoplankton -> excrete -> recycled by bactiria and lastly taken up once again by phytoplankton
When production is way higher than biomass the F ratio is low because it means it is a lot of recycled material. this is what we see in summer where nutrients are pretty depleated. |
| How to measure primary production? | 1) measure over time:
Could be mg carbon pr day
2) measuring c14 over time. See how much is incorporated over time. You could incubate a cell with c14 and measure again after x amount of hours and then see how much they have taken up through photosynthesis
3) empirical relationships based on satelite data. |
| What do you call the type of bloom that can NOT be measured from satelite | Subsurface bloom |
| What is the microbal loop? | 10% of energy is transferred between trophic levels.
Picophytoplankton are very small cells. |
| foodweb | The fewer the steps the more yield %.
In summer there are more steps cause of more recycled material.
Step 2-3 is very important in the microscopic foodweb bacteria being eaten by heterotrophic nanoflagelates. Calanus is a copopod. This yields a lower biomass for higher trphic levels. |
| Quickly sum up what is typical for "bloom" in summer | Low F ratio, grazers are more important and most biomass is grazed down even thogh there can be high production. Smaller phytoplancton are more dominant. |
| Autum bloom what happens? | The mixing layer increases and more nutrients allow growth and a second smaller bloom.
Autum bloom has increased in arctic. Less ice in autum makes more phytoplancton in autum. |
| What happens in winter? | Different strategies:
Resting stages on bottom is not very important in the oceanic areas because they are too deep for upwelling. More important in coastal areas where upwelling can go all the way to the bottom.
I think they have resting stages in the bottom in coastal areas so they can be brought back up with nutrients
Nutrients are also brought bak up during winter. |
| How to meassure biomass in free water colomn?
(Add more questions about this in cruise section? | Neskin bottle
- can open in specific depths
- quantitative
- how many
phytoplankton net
- dont know the sspecific depth
- qualitative
- which organisms |
| What assumptions did sverdrup make in his paradime | See picture
and also: production of organic matter by photosynthesis is proportional to energy of radiation |
| What do we expect in the future in terms of species distribution | More flagaellates/diatoms relative to now because of climate change. |
| How do different types of glaciers generally influence phytoplankton? | A typical glacier on land will have runoff then bring material from land (sediments and nutrients) into the fjord. Sometimes a lot of sediment inibits light but if there is not to much sediment it can be beneficial for phytoplankton.
Close to glacier euphotic zone is not deep because of sediment.
Glaciers going directly into sea:
Makes more phytoplankton production often. There is always exchange of water into the fjord. Then the water rises to the surface and makes upwelling at the glacier front. To close to the glacier is light to little but further away from the glacier is a lot of primary production. |
| how are nutrients distributed in the vertical in arctic vs subarctic | in subarctic nutrients are quickly depleeted and are therefor often found depper than in arctic where they are deepleted slower |
