Transfer of Energy and Material to the Deep SeaFormation and Fate of Marine Snow

The Biological Pump

The ‘Missing’ Carbon

Atmospheric Increases are ~3.2 Gt y-1

Anthropogenic inputs are ~5.4 Gt y-1

~2.2 Gt of anthropogenic Carbon input is accounted for in the atmosphere, more than half is missing.

The Biological Pump

Vertical Flux of Organic Particles to the Deep Sea

Sediment TrapsFLUX

gC m-2 d-1

What are sediment traps really measuring?

• Inorganic, organic, and swimming• Downward fluxes only• Relative motions and particle sorting• Statistical funnel

Particle Intercept Trap (PIT)

‘Honjo’ Sediment Trap

Reduction in Vertical Flux over Depth

1 2 3The Martin Curve

Martin and Knauer 1981

50% losses by 300 m75% losses by 500 m90% losses by 1500 m

Explanations for the Shape of the Martin Curve

• Bacterial decomposition = remineralization of Carbon• Cryptic swimmer distribution• Smaller, slower sinking particles at depth

Size distribution of particles in the sea

Flux = Mass x Sinking Rate

McCave 1984

Marine Snow

Marine Snow Particles

Marine Snow Particles

Discarded feeding houses

Marine Snow Particles‘Comets’

Sinking of particles in the sea

Flux = Mass x Sinking Rate

V d2 x (s-w)

V = settling velocityd = particle diameters = density of particlew= density of water

Stoke’s Law

Contribution of Marine Snow to Vertical Flux

Narrow window of particle sizes which are large enough to sink but numerous enough to be widely distributed.

2 200 20,000 (um)

Snow

Bodies

Cells

cell chainplankton

poopaggregates Willie

X

1-10 m

50 m

100 m

2000 m

Available towater columnprocesses

Aggregates

Composition of Marine Snow

Once living material (detrital) that is large enough to be seen by the unaided eye.

Described first by Suzuki and Kato (1955)

High C:N makes for poor food quality.

• Senescent phytoplankton • Feeding webs (e.g., pteropods,

larvaceans)• Fecal pellets• Zooplankton moults

Formation of Marine Snow

Type A: Mucous feeding webs are discarded individually.

Type B: Smaller particles aggregate into larger, faster sinking particles.

Aggregates

How does Type B Snow Form?

Coagulation Theory: Particle Collision Rates

Differential settling velocitiesTurbulent motions

How does Type B Snow Form?

Coagulation Theory: Particle Stickiness

Transparent Exopolymeric Particles

TEPs

Related to bloom conditions of phytoplankton:• High phyto concentration• Nutrient depletion• Self-sedimenting strategy?

Properties of Type B Marine Snow

• High porosity (99% water)• Carbon source for bacteria and protozoan grazers

(gases often produced)• Some snow >90% bacteria• Pore water exchanges dictate chemical gradients

Marine Snow Dynamics

Marine Snow and Surface Production Cycles

Coupled

De-coupled (excesses)

Where will Snow Contribute to Missing Carbon?

Only ~1% of annual newproduction reaches sea floor

High Nutrient (Nitrate) - Low Chlorophyll (HNLC)

Eastern Tropical PacificSub-Polar North PacificSouthern Ocean

Evidence for Iron Limitation in ETP

• Macro-nutrients at non-limiting concentrations• Small-scale bottle and microcosm experiments• Natural additions of iron from land nearby

Galapagos Islands

IronEx IIronEx II

Southern Ocean

OrganizationGreenSea Venture, Inc.

www.greenseaventure.com

Ocean Technology Group (U. of Sydney, Australia)

www.otg.usyd.edu.au

Ocean Carbon Science, Inc.*(Formerly Carboncorp USA) www.rsrch.com/carboncorp

Principal Michael Markels, Jr. Ian S.F. Jones Russ George / Robert Falls

FertilizerFe-lignosulphate

or other iron chelateNH3 solution

Proprietary nutrient supplements, Fe + ?

Approach

- Fertilizer released along a "spiral fertilization" path

- Small, floating nutrient pellets

- Atmospheric nitrogen fixed as ammonia (NH3) via industrial process (using fossil fuels)- Ammonia pumped from a land- or ocean-based (i.e., floating) facility for release into the surface ocean near the edge of the continental shelf - Ammonia discharged via "plurality of riser pipes"

- Retrofit commercial ocean liners for releasing mix into the propeller wash at an "appropriate" time(s) during a voyage- Algal response monitored by satellite imaging and shipboard instrumentation

Claimed Efficacy

1 t Fe/yr added to HNLC ocean would capture 30,000 t C/yr [11].

600,000 to 2,000,000 t CO2 can be sequestered by fertilizing 5000 sq. mi. of Equatorial Pacific Ocean within 20 days [3].

Adding 1 t N/yr to the ocean sequesters 5 t C/yr from the atmosphere, even for long-term, gigaton-scale ocean fertilization application [12].

Not specified

Ocean Area(s) Targeted for Fertilization

 Equatorial Pacific Ocean - Chilean coastal upwelling zone

- Coastal waters of "Low income food deficient" nations

- "Plankton domains" along major shipping lanes

Claimed Cost Estimate $7 to $7.5 /tC [3] $18 to $55 /tC [1,2] Not available

Markels, Jr., M., 1995, P/N 5433173, Method of improving production of seafood. Markels, Jr., M., 1996, P/N 5535701, Method of increasing seafood production in the ocean.Markels, Jr., M., 1999, P/N 5967087, Method of increasing seafood production in the barren ocean.Jones, Ian S. F. et al., 1999, P/N 5992089, Process for sequestering into the ocean the atmospheric greenhouse gas carbon dioxide by means of supplementing the ocean with ammonia or salts thereof. [Patent for the Ocean Technology Group at the University of Sydney, Australia. Includes a schematic for the ‘nourishment’ process.]Howard Jr., E.G. and O’Brien, T.C. (assignee: E.I. du Pont de Nemours and Company), 1999, P/N 5965117, Water buoyant particulate materials containing micronutrients for phytoplankton. [Du Pont’s variant on Markels’ patented idea of floating pellets with embedded iron fertilizer. Specifies a wide range of compounds for making pellets with.] Markels, Jr., M., 2000, P/N 6056919, Method of sequestering carbon dioxide. [Markels’ first patent emphasizing carbon sequestration. Markels’ previous patents were focused upon fish production by fertilization, although the potential for carbon dioxide capture was also mentioned in the patents (see below).]Markels, Jr., M., 2001, P/N 6200530, Method of sequestering carbon dioxide with spiral fertilization. [Note the incremental, almost annual "improvements" being made to the patented technology.]Markels, Jr., M., Filed in 2001, A/N 20010002983, Method of sequestering carbon dioxide with a fertilizer comprising chelated iron. [Patent application number six for Markels. Markels proposing a "system" for tracking sequestered carbon.]

U.S. Patents Filed

Extreme Deposition: Food Falls

• Rare events (not recorded in traps)• Deposit large amounts of high quality organic

materials to sea floor (low C:N)• Rapid sinking, reach 1000s of meters in few days• Large bodies that remain intact (whales, fish,

macroalgae, etc)

Deep sea benthic respiration out of balance with traps

How frequent are food falls?

~200 kg C km-2 d-1

Same as about 1 fish 5000 m-2 d-1

What impact will that fish have on the deep sea community?

At 2000 m...

A 10 kg fish will be respired completely...

In 1 DAY over a 0.5 km2 areaIn 1 YEAR over a 0.002 km2 area

At 5000 m...

That same 10 kg fish will be respired completely...

In one DAY over a 16 km2 areaIn one YEAR over a 0.044 km2 area

Fall event

2000 years

Carbon

10 kg Food fall respired in a 1 m2 area

FALL

Particles distributed by feeding

Dissolved Organics

Fecal materials

Spatial re-distribution of organic material

current

Rattail or grenadierCoryphaenoides cinereus

Galatheid crab (Munidopsis sp)

Community response to arrival of food

Non-motile, infaunal

Motile benthic inverts (amphipods, crabs)

Fishes (grenadiers)

Local diversity gradient

Sediment Time-Series

Siegel and Deuser 1997

The Statistical Funnel

Why isn’t the Eastern Atlantic Fe-limited?