Climate, Oceans and Phytoplankton: That Sinking Feeling* *With apologies to Bill Forsyth and Jorge Sarmiento (Nature 2000) Conservation Biology Oct 22, 2004

Our plan for today: Conservation and the ocean. Why? Global carbon budget. How? Carbon sequestration: injection How? Carbon sequestration: “biological pump”

Our plan for today: Conservation and the ocean. Kyoto Carbon credits.

How the oceans influence climate Oceans and atmosphere are tightly linked. Oceans are critical for storing heat (and carbon) Powerful currents are moving waters - transporting heat Deep-water currents influence extremes in climate Minor changes in ocean current mean major (large scale) climate variations

Global Carbon Cycle

Roger Revelle “the grandfather of the greenhouse effect...”  40% of the atmospheric carbon remains in the atmosphere.  2/3 from fossil fuel; 1/3 from clear of forests.  Sent warning of sea level changes due to greenhouse effect... CARBON CYCLE ISSUES CO2 (ppm)

DEEP WATERS are Undersaturated with CO 2

Absorption of CO 2 in the Ocean: “new” and “void” CO 2 (aq) CO 2 + Ca +2 CaCO 3 (ppt) (reactive, catalytic)  pCO

CARBON SEQUESTERING - a PANACEA? Depth Organic carbon PSN P Inorganic CO 2 Case 2Case 1

Depth P Inorganic CO 2 Option 1 Carbon Sequestering: injection

Option 1 Carbon Sequestering: injection Peter Brewer (MBARI) Collection of CO 2 gases from industry Pump to below 1000 m. CO 2 gases will be denser than seawater and will remain as a liquid or as ice. Movement depends on mid- or deep-water circulation. Plume formation and water circulation

Movement Uncertain effects on benthic communities Transportation and processing costs

Option 2 Carbon Sequestering: Biological pump Depth Organic carbon PSN

IRON LIMITATION IN MARINE SYSTEMS

John Martin “Johnny Ironseed”  Looked at the oceans with an analytical eye....  Developed an analytical approach that opened up a field of ocean chemistry  “Give me half a tanker, and I’ll create the next ice age.” Linked PHYTOPLANKTON PRODUCTIVITY With the CARBON CYCLE

PhosphateSilicate Nitrate Cell Biomass + growth = ∑ needs (C, N, P, ?)

Nitrate Cell Biomass + growth = ∑ needs (C, N, P, Fe ) Redfield ratio: 106:16:1: C:N:P:Fe (cellular) So … for every gram of iron added, draw down 2.9 tonnes of carbon.

So what is limiting the growth of the phytoplankton? Residence Time in Upper Waters (years) Concentration mol L -1 FeSO 4 Fe +2 + SO 4 -2 Fe +3 Fe(OH) x (ppt)

How does iron get to the Pacific? April 2001

“CLEAN” sampling and handling techniques Martin’s Small Bottle-experiments (small scale)

Meso-scale studies to “test” the iron hypothesis: Does adding iron stimulate the growth of phytoplankton? IronExII SOFeX

SOFeX - 64 km 2 with 1 nM FeSO 4... So, some ecosystems have major Nutrients ($$$) but limiting levels of Iron (cheap!)

Quantifiable reduction in atmospheric CO 2 in "patches" of iron fertilization. SOFEX. Watson, A.J., and others Effect of iron supply on Southern Ocean CO2 uptake and implications for glacial atmospheric CO2. Nature 407:

Started with a mixed flagellate and diatom community

Ended with a DIATOM-only community.

IronExII SINK! Biological Pump! Remove CO 2 via Productivity

Meso-scale studies to “test” the iron hypothesis: Does adding iron stimulate the growth of phytoplankton? IronExII SOFeX

To get the Biological Pump... Pumping, need to grow diatoms and other heavy cells. Does the addition of iron always result in these heavy cells? Good (sp. density 1.1)... Better (sp. density 1.5)... Terrible! (sp. density 1.1)

SERIES: fertilization of Ocean Station PAPA (2002) Funded through SOLAS (NSERC, CCAF etc.) Iron fertilization to measure: Growth, gas production, sinking 64 sq. km FeSO4 addition ~ 1-2 nM Fe in the surface water

SERIES: fertilization of Ocean Station PAPA (2002) Funded through SOLAS (NSERC, CCAF etc.)

SERIES: fertilization of Ocean Station PAPA (2002) Funded through SOLAS (NSERC, CCAF etc.)

FeSO 4 and SF6 (gas)

SERIES: fertilization of Ocean Station PAPA (2002)

In warm waters... FeSO 4 SO Fe +2 Fe +3 Fe(OH) x (ppt)

In warm waters... But the cold waters of the North may be a different story

Different story FeSO 4 SO Fe +2 Fe +3 Fe(OH) x (ppt) CO 2 CO 2 CH 4 DMS N 2 O

Consequences of fertilizing OS PAPA... Few Diatoms, lots of flagellates. Flagellates were stimulated to grow  Respire at > 90% of carbon  Produce GHG that are more destructive than CO 2 The resulting phytoplankton are a bit suspect....

.... HARMFUL ALGAL BLOOMS The definition of a HAB is not clear-cut, since it is a societal term, not a scientific term, that describes a diverse array of blooms (both macroscopic and macroscopic) that can cause detrimental effects to national economies.

Responsible for Paralytic Shellfish Poisoning (PSP) One flagellate that dominated is....

Chaetoceros sp. (a non-specific fish kill species) One of the diatoms that dominated was...

Another was Pseudo-nitzschia … a toxigenic diatom which produces domoic acid - responsible for Amnesiac Shellfish poisoning (ASP) in local waters

There’s no great degree of success. chemistry of iron limits use at different zones The measurement of success is uncertain. The consequences of fertilization may be detrimental at the regional scale HABs toxins May show no net benefit to GHG emissions. CO 2 respired quickly O 2 stress in surface waters CH 4, DMS and N 2 O produced. Conclusions … so far.

Public ponderings…on scientific responsibility. “There are many of us who consider the oceans to be sacred…. We’ve let the cat out of the bag. We have to keep looking at it now whether we like it or not.” - Ken Coale “The biggest danger, in my view, is that large-scale iron fertilization will occur without the necessary understanding of just what will happen on scales ranging from single cells to ecosystems.” - John Martin