Bio Lodge Eeeeeeeee

Front 1

What is iron used for?

Back 1

CYPs use iron for photosynthesis and respiration. Bacteria/enzymes use for N assimilation.

Front 2

Redfield Ratio

Back 2

~106:16:1 C:N:P

Front 3

In terms of Redfield Ratio, what is iron?

Back 3

106:16:1 - C:N:P, Fe = .008 or 13250:1 C:Fe

Front 4

Why is iron limiting?

Back 4

It is abundant but not in bioavailable form.

Front 5

What is a siderophore?

Back 5

A tiny compound released by some phytoplankton to scavenge iron.

Front 6

What are sources of iron to the ocean?

Back 6

Rivers
Resuspension of coastal sediment particles
Upwelling of deep water
Dust

Front 7

Is iron really limiting in situ?

Back 7

Nearly a dozen or so field experiments have shown that iron fertilization works, but that's not the whole story.

Front 8

Takeaways from IronExI

Back 8

Equatorial Pacific. Biomass doubled in first few days. Fe particles became bound and sank. Zooplankton growth caught up. Zn or Si may also have been limiting. Patch eventually subducted.

Front 9

Takeaways from IronExII

Back 9

Equatorial Pacific. More Fe added. More measurements taken. Fe and grazing co-regulate iron in HNLC. Increased Fe changed physiology of picophytoplankton, but grazing increased with increased abundance.Draw down of major nutrients and carbon seen as result of growth of phytoplankton.

Front 10

Do these experiments show that iron fertilization can work?

Back 10

Ocean iron experiments not designed to test the efficacy of adding Fe to sequester C. It isn't clear that the basic idea will work, but if it does it will be at a much lower efficiency.

Front 11

Are there drawbacks to ocean iron fertilization?

Back 11

Adding iron could increase export of particulate organic matter, leading to hypoxia/anoxia, increasing denitrification.

Front 12

Cavandar-Bares (1999) did what?

Back 12

Analyzed size fractionated chlorophyll to monitor change in > and < 10 um size classes. Used taxon specific pigment measurements to distinguish between changes in cell number and cell chlorophyll.

Front 13

What is Fv/Fm?

Back 13

Photochemical quantum efficiency. A ratio of inflourescence that describes how efficiently cells use light in photosynthesis? An increase in photochemical efficiency means efficiency was previously limited.

Front 14

How did Cavandar-Bares (1999) distinguish between cell number and cell chlorophyll and why?

Back 14

Taxon specific pigment measurements were used to distinguish between the number of cells and chlorophyll per cell to investigate changes per cell compared to bulk chlorophyll measures.

Front 15

Cavandar-Bares (1999) report was the first to document changes in what species?

Back 15

Prochlorococcus.

Front 16

What can an increase in Chl a mean?

Back 16

An increase in large cells or increased cellular pigment concentration.

Front 17

If cellular pigmentation concentration per cell increases with iron enrichment, then _____.

Back 17

This proves cells were iron limited.

Front 18

Cavandar-Bares (1999) warn that increased fluorescence is not necessarily correlated to ______.

Back 18

The degree of iron limitation because pigment per cell and species composition must also be considered.

Front 19

In Cavandar-Bares (1999) both FL and FALS (forward angle light scatter - correlated to cell size) increased. So...

Back 19

It is not clear if the volumetric concentration of pigment increased or the pigment increased in proportion to cellular volume. Note: FL does not equal Chl a & FALS does not equal volume.

Front 20

True or False? When cell size/species is considered in Cavandar-Bares (1999), there is a significant difference in response to iron enrichment in IronExII.

Back 20

TRUE.

Front 21

What were some of the results of Cavandar-Bares (1999) in size fractionation?

Back 21

Pennate diatoms increased substantially inside the patch. Ultraplankton increased both inside and outside the patch so their abundance cannot necessarily be attributed to iron fertilization. Nanoplankton increased on day 3, doubled on day 4, and then returned to out of patch numbers. Prochlorococcus actually decreased inside the patch- thought to be due to grazing. Synechococcus increased two-fold and then returned to out of patch numbers.

Front 22

Cavandar-Bares (1999) size fractionation takeaway

Back 22

Changes in numbers of size classes show that even though some of the smaller phytoplankton increased two-fold, only the initially rare pennate diatoms broke free of grazing pressure.

Front 23

Possibilities for slow in pennate diatom growth in IronExII:

Back 23

Light limitation due to bloom.
Increased grazing or sinking.
Silica limitation.

Front 24

Cavandar-Bares (1999) summary:

Back 24

Measured a dramatic size-based shift in cells >10um increased 60 fold. Point is, phytoplankton community structure changes dramatically with nutrient enrichment.

Front 25

How is Fe supply linked to global climate?

Back 25

The biological pump. Sinking of C sequestered in POM out of exchange zone with atmosphere.

Front 26

What happens to picophytoplankton in IronExII according to Cavandar-Bares (1999)?

Back 26

Get healthier (increased pigment per cell and cell volume) but not much more abundant due to grazing.

Front 27

How does the growth of large phytoplankton support iron fertilization as climate change mitigation?

Back 27

Inefficient growth of attendant large grazers, allows time for sinking of large diatoms and their fecal pellets, sequestering more organic material and, therefore, carbon.

Front 28

Do large or small phytoplankton tend to benefit from Fe enrichment? Why?

Back 28

Large diatoms. Smaller phytoplankton are more efficient at growing under nutrient poor conditions, and growth rates are kept in check by small zooplankton. Larger diatoms grow better in nutrient rich conditions and attendant large zooplankton take longer to reproduce, thus blooms occur.

Front 29

The class size of phytoplankton that dominate iron enriched patches is dominated by ______.

Back 29

The amount of iron dissolved.

Front 30

For ocean fertilization to successfully mitigate climate change, what is one thing that must happen?

Back 30

Phytoplankton must grow, locking up carbon and nutrients into organic material, and this organic material must be transferred into the deep ocean so that it does not simply get recycled near the surface where carbon will be released back into the atmosphere.

Front 31

Increases in chlorophyll concentration suggest _______.

Back 31

Phytoplankton are able to use more of the available light to grow.

Front 32

What is Ekman transport?

Back 32

The 90 degree net transport of the surface layer due to wind forcings.

Front 33

What direction does Ekman transport move in the northern hemisphere? And the southern? Why?

Back 33

right in northern; left in southern; Coriolis Effect

Front 34

How does Ekman transport influence upwelling?

Back 34

Ekman transports water offshore when winds blow along the coast and toward the equator: causing upwelled water to replace the transported surface water.

Front 35

What influences the rate of upwelling?

Back 35

Strength & direction of wind; structure of water (MLD); ocean topography (canyons, slope shelf); large scale current structure

Front 36

Why does zonation occur in the Peruvian upwelling?

Back 36

Phytoplankton must acclimate to increase in nutrients. Once they do biomass increases rapidly and then nutrients become depleted. (not ready- shift up- shift down).

Front 37

Compare and contrast the Canary and Peruvian upwelling systems.

Back 37

Canary has a broader shelf, lower source water nutrients, and stronger but less predictable winds.

Front 38

When does a bloom develop in the Canary system?

Back 38

Only between wind events when the surface mixed layer becomes shallower than the critical depth.

Front 39

What is critical depth?

Back 39

production equals respiration loss plus consumption

Front 40

Summarize Iriarte & Gonzalez (2004).

Back 40

Studied phytoplankton size class response to El Nino conditions off of northern Chile. Found that during EN, size more evenly distributed, PP, Chl a, & C export low; whereas, during return to La Nina conditions PP, Chl a, & C export increase- although more variable- along with increased phytoplankton size. Believe increased export due to increased sinking rates and fecal pellet size/sinking rate, and less efficient grazing.

Front 41

Which system is more efficient, picoplankton/microbial or micro&macro plankton?

Back 41

Picoplankton and their attendant zooplankton are more efficient, recycling more nutrients in the surface layer.

Front 42

Iriarte and Gonzalez (2004) set out to do what of the northern coast of Chile?

Back 42

To assess the changes in size-fractionated primary production, biomass, and the sedimentation rate (export/carbon flux) of phytoplankton in a coastal area during and after El Nino.

Front 43

Which phytoplankton size classes are most common during EN according to Iriarte and Gonzalez (2004)?

Back 43

Pico and nanophytoplankton;
pico = 0.2-2um and nano = 2-20um

Front 44

What are normal phytoplankton conditions inthe northern Humboldt Current exchange?

Back 44

highly productive community dominated by chain-forming diatoms

Front 45

What happens to sea-level near the north coast of Chile during El Nino?

Back 45

Thermocline fluctuates with remotely wind forced Kelvin waves at the equator - ENSO western Pacific builds and sea-level & thermocline shift in east as a result

Front 46

How does the temperature of water impact phytoplankton during EN according to Iriarte & Gonzalez (2004)?

Back 46

Warm water moves toward the coast, increasing stratification and suppressing cold nutrient-dense upwelling water

Front 47

What happens to the phytoplankton community during EN?

Back 47

Pico- and nano palnkton dominate the phytoplankton community, accounting for more than 505 of Chl a and PP in coastal waters.

Front 48

Iriarte & Gonzalez (2004) were looking at primary productivity, phytoplankton size class changes and _____>

Back 48

Sedimentation rates/export/flux of carbon to deep

Front 49

When did Iriarte & Gonzalez (2004) find microphytoplankton growth was enhanced?

Back 49

After El Nino, with the re-establishment of cold nutrient-rich upwelled water, >23um microphytoplankton productivity and biomass increased.

Front 50

How did sedimentation rates change during EN in Iriarte & Gonzalez (2004)?

Back 50

Sed rates decreased.

Front 51

Why do Iriarte & GOnzalez (2004) believe sedimentation rates decrease during EN?

Back 51

EN favors a shift to microbial loop-based food chain, more efficient, slower sinking rates of smaller phytoplankton

Front 52

Why do smaller phytoplankton grow during EN?

Back 52

Smaller phytoplankton grow more efficiently in nutrient poor/oligotrophic waters.

Front 53

True or False. Iriarte & Gonzalez (2004) believe unused particulate organic carbon (that doesn't sink or get grazed) might be moving seaward (horizontally) in filaments or eddies during EN.

Back 53

True.

Front 54

Tam et al. (2008) developed what for the Northern Humboldt Current Ecosystem?

Back 54

Ecotrophic Model, modeling the NHCE food web based on ecosystem function

Front 55

Tam et al. (2008) modeled trophic change during El Nino. Summarize these changes.

Back 55

Overall reduction in biomass, increase in dinoflagellates and macrozooplankton. Reduced organization and energy flows of ecosystem.

Front 56

Tam et al (2008) suggest that sardines are better suited to the phytoplankton size class shift during El Nino. Why?

Back 56

Sardines are more efficient removers of small particles than anchovy.

Front 57

What is a dinoflagellate?

Back 57

Photosynthetic and mixotroph plankton group. Protist/eukaryote (microorganism/single cell with nucleus). Produce cysts/resting phase.

Front 58

What are euphasiids?

Back 58

Example: krill. Have deeper distribution in tropical pacific.

Front 59

How is the size of an ecosystem measured? (Tam et al 2008)

Back 59

The size of an ecosystem can be measured by its total activity in terms of energy flows, or by the total system throughput.

Front 60

Did the total system throughput change in the Tam et al (2008) ecotrophic model?

Back 60

Yes. In addition to the total biomass reduction (-26.7%), total system throughput reduced dramatically (-58.7%), along with a reduction of absolute energy flows for prey consumption, exports, respiration and to detritus.

Front 61

What controlled ecosystem size/energy throughput during El Nino in the Tam ecotrophic model?

Back 61

Bottom-up control; the shift in phytoplankton species increase consumption (by zooplankton) and decrease export (because of efficient consumption).

Front 62

What is a transfer efficieny?

Back 62

The efficiency with which energy is transferred from one trophic level to the next. Determined by combination of efficiencies relating to resource acquisition and assimilation in an ecosystem.

Front 63

What were the transfer efficiencies under LN & EN conditions in the Tam ecotrophic model?

Back 63

LN > 10%
EN reduced transfer efficiencies

Front 64

How did the trophic level of certain species change during El Nino in the Tam ecotrophic model?

Back 64

The trophic level (primary, secondary, tertiary consumers) increased during El Nino.

Front 65

How did energetic indicators (PP, net PP) change during El Nino in the Tam model?

Back 65

Most energetic indicators decreased except biomass/throughput ratio, indicating a more energetically efficient ecosystem during El Nino.

Front 66

How was the Tam ecotrophic model different from other NHCE models of EN impacts?

Back 66

Separated plankton species into diatoms, dino- and silicoflagellates, and micro- (20-200um), meso- (200-2000um), and macro- zooplankton (2-20mm); separated demersal groups, and included jumbo squid into model.

Front 67

What were the three main impacts on the EN food web according to the Tam ecotrophic model?

Back 67

1) dramatic shrinking of ecosystem size/energy throughput in terms of energy flows and ecosystem organization; 2) slight changes in overall functioning (proportion of energy flows used for respiration, consumption by predators, detritus and export); and, use of alternate pathways through more zooplankton predation on primary producers, leading to a higher impact of the fisher on ecosystem flows.

Front 68

What are common traits of polar food webs?

Back 68

High seasonality in light.
Very low temperatures.
Sea ice influences physics, optics and biology.

Front 69

At what temperature does seawater begin to freeze?

Back 69

-1.8 degrees C

Front 70

Do sea ice crystals contain salt?

Back 70

No. Ice crystals exclude salt.

Front 71

What happens to salt if it isn't included in ice crystals?

Back 71

Brine concentrates in channels and is eventually transferred to seawater. Sailinity is thus increased.

Front 72

How is sea ice a habitat?

Back 72

Brine channels colonized by algae; and, underside of ice important habitat for algae and animals.

Front 73

What are sympagic biota?

Back 73

algae and microbes that like to live in brine channels or on the underside of sea ice.

Front 74

How does sea ice influence stratification?

Back 74

Stratification due to ice melt allows intense phytoplankton bloom

Front 75

What is the Arctic Ocean like?

Back 75

Broad, shallow seas with high seasonal production surrounding a deep basin; seasonal sea ice production on shelves; lots of riverine input of fresh water, nutrients and organic matter.

Front 76

Name important phytoplankton in the northern Bering Strait.

Back 76

Diatoms, coccolithophorids, Phaeocystis

Front 77

What is the largest benthic predator? How does it feed?

Back 77

Gray whales. They bite sediment and sift out benthos. Gray whales are also important in releasing nutrients in water column.

Front 78

What water is exchanged with the Arctic Ocean?

Back 78

Entrainment of north Atlantic and Pacific water into Arctic, warm salty water mixes with cold, freshwater. In addition to heat and salt, nutrients and plankton are also exchanged.

Front 79

What's the Southern Ocean like?

Back 79

Ocean currents surrounding an ice-covered continent. There is little terrestrial input of freshwater and nutrients. Relatively narrow shelves.

Front 80

What's the deal with Antarctic currents?

Back 80

Antarctic circumpolar current - divergence between ACC and landward countercurrent upwelling.

Front 81

What limits production in polar regions?

Back 81

Temperature and light. Temperature does not limit primary or secondary production. Seasonality- some regions are ice free for one month or less.