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Home , Assimilation (biology), Meroplankton, Nekton, Trace metal, Water column

Includes the coastal zone and the , the realm of the oceanographer

I. Circulation

II. Column Production A. Coastal B. Open Oceans E. Micronutrients F. Harmful Algal Blooms

III. and

The is also important to benthic production over a great part of the ocean

c

Winds and forces push to the right in the northern hemisphere, left in the South

Because of the Coriolis Effect, surface currents In the main ocean basins, the currents form do not move parallel to the wind but at an angle circular systems (gyres) that dominate global of 45 deg. from wind direction circulation and climate.

1 Cold to Hot

What are the important primary producers Production by in the water column? is generally lower than that of bottom

All microscopic and mostly as single Coccolithophorids cells or short chains Cryptomonads

Global Pattern of Marine Primary

May

gyre gyre gyre

gyre gyre gyre

2 Forcing agents for Phytoplankton Production

High Low Chlorophyll regions (HNLC) Especially Intense Herbivory or Trace Limitation? Nitrates ( , , , )

Ocean Cycle

Seasonal profile, coastal Maine

The Compensation depth is a physiological concept: The depth at which the rate of for an individual equals the rate of by that plant. Compensation depth: photosynthesis = respiration The Critical depth is an ecological concept applied to the whole community of plants and related to vertical mixing of the water:

Higher light absorption by more dense

3 The Compensation depth is a physiological concept: The depth at which the rate of photosynthesis for an individual plant equals the rate of respiration by that plant.

The Critical depth is an ecological concept applied to the whole community of plants and related to vertical mixing of the water:

It is the depth to which the total phytoplankton may be circulated and still spend sufficient time above the compensation depth to have the total production equal the total respiration for a given time period Thus the depth of vertical mixing is another important determinant of productivity

Seasonality Cycles are in the different temperate in other zone regions results in two distinct peaks

Spring Summer Autumn Winter Spring

Lenes et al.

I. Ocean Circulation

II. Water Column Production A. Coastal Oceans B. Open Oceans E. Micronutrients F. Harmful Algal Blooms

III. Zooplankton and Nekton

4 along the California has different effects on productivity depending on river inputs and width of the margin (Ken Bruland and Colleagues)

Iron Limitation of Ocean Phytoplankton 10 nM Observations Iron Experiments  Fe - Tropical Pacific Ocean,near - Multiple additions of dissolved the equator, rich in N iron to attain 2 nM (225 kg in and P but low in plant life. 80 km2). Sulphur Hexafluoride used as tracer. < 1 nM - Control is area with no iron - Light levels are plentiful  Fe added, only SF6 and acid solution - What limits plant biomass? - Navigate ship following buoys that mark the water masses - Measure light, chlorophyl a, , biomass, CO2 pp

5 Iron Point Source Iron Ex Experiments • Results of iron enrichment experiments taken from the US JGOFS (Joint Global Ocean Flux Study) newsletter Experiment Date Results IronExI 1993 3-fold increase in chlorophyll Photochemical Quantum Efficiency IronExII 1996 10-fold increase in chlorophyll, 90µatm drawdown in CO2 SOIREE 1999 6-fold increase in chlorophyll, 25µatm drawdown in CO2

• Photosynthetic capacity: immediate and sustained increases. EisenEx 2000 4-fold increase in chlorophyll • Phytoplankton Growth rate: doubled, abundance increased 20x. SEEDS 2001 40-fold increase in chlorophyll • Nitrate concentrations: declined by half. SOFeX (N) 2002 Greater than 10-fold increase in chlorophyll, Greater than 40µatm drawdown in CO2 • Shift dominance to larger diatoms; release control by herbivory SOFeX (S) 2002 Greater than 10-fold increase in chlorophyll, Greater than 40µatm drawdown in CO2 SERIES 2002 Greater than 10-fold increase in chlorophyll

Iron Ex Experiments What happens to the Carbon Produced during these Blooms?

This graph shows the difference in the rate of carbon assimilation and drawdown in the Equatorial Pacific and the .

Boyd et al. 2007 Science 315 Pg. 312

6 The are the drifting larvae of bottom-dwelling animals

I. Ocean Circulation

II. Water Column Production A. Coastal Oceans B. Open Oceans E. Micronutrients F. Harmful Algal Blooms

III. Zooplankton and Nekton

The principal herbivores of phytoplankton Others use filters to remove from the water in the ocean are the which feed by creating currents, and capturing algae using a “feeding basket” made by appendages

Salp butterfly

Predatory Zooplankton Many Phytoplankton and Zooplankton are bioluminescent; they account for most of the bioluminescense in the sea

Arrow worm

7 Many Phytoplankton and Zooplankton ( and ) The nekton consists mostly of Larger, undergo daily vertical migrations of IV. The Nekton predatory type animals a meter to tens of meters

Anchovy School of

Tuna

V. Water Column Water Column Food Web (traditional view) (Simplified)

The , an important Water Column component of water column trophic dynamics Food Web (modern view)

To Zooplankton

From Algae

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