Fragile ocean ecosystems threatened by plan to dump iron

Fragile ocean ecosystems threatened by plan to dump iron

Letter to the Editor The Indpendent (UK)

14th May 2007

A US company plans to deposit large quantities of iron in the Pacific (Independent report, 3 May). The intention is to demonstrate this will remove carbon dioxide (CO2) from the atmosphere to the deep ocean where it will be locked away for centuries (sequestration). The plan is that they will do this commercially to offset the carbon footprint of various industries.

Several open-ocean experiments have attempted to quantify the level of sequestration caused by purposeful fertilisation by iron (an essential micro-nutrient). Plant biomass increased but sequestration into the deep ocean (below 1,000m) was not demonstrated. The particles carrying this carbon degrade rapidly in the upper ocean and it is likely that almost all of the CO2 taken up is released back to the atmosphere within a year. In addition, there is the considerable carbon cost of the fertilisation process itself.

Although we welcome further experimentation, such work must be done alongside other studies such as the measurement of deep-ocean, downward carbon flux and analysis of ecosystem changes.

This does not appear to be the case in the forthcoming experiments and the temptation will be to conclude erroneously that any biomass increase is evidence of enhanced sequestration. Commercial exploitation of this technique could cause substantial harm to the ocean ecosystem and may even reduce its ability to sequester carbon. Such an assault on these remote and fragile ecosystems should not be done until we can show there are demonstrable benefits that outweigh the costs.

DR RICHARD LAMPITT, DR ERIC ACHTERBERG, DR JOHN ALLEN, DR DEBORA IGLESIAS-RODRIGUEZ, DR EKATERINA POPOVA, DR RICHARD SANDERS, PROF JOHN SHEPHERD FRS, DR DENISE SMYTHE-WRIGHT, DR MERIC SROKOSZ, PROF PETER STATHAM, DR TOBY TYRRELL, DR ANDREW YOOL

NATIONAL OCEANOGRAPHY CENTRE, SOUTHAMPTON