Carbon Dioxide absorption

I have no data but I wouldn't put it past Kudzu as being up there. It seems to have taken over Georgia (USA).

Yeh. Dandelions might qualify too. Also, there are some very fast growing trees of the leucania variety that might qualify.

Peat. (We call it sphagnum peat moss here in US. In Ireland they just call it peat)

It probably holds around 25% of sequestered carbon in terrestrial systems.

See this link: http://www.mcgill.ca/reporter/32/15/roulet/

Factual rather than politics in this report.

Forests here in the US are estimated to sequester about 13-14% of the carbondioxide released here anthropogenically:

Land use, land-use change, and forestry activities in 2004 resulted in a net carbon sequestration of 780.1 Tg CO2 Eq. (212.8 Tg C) (Table 7-1 and Table 7-2). This represents an offset of approximately 13 percent of total U.S. CO2 emissions. See page 2 of this document:

http://epa.gov/climatechange/emissions/downloads06/06LULUCF.pdf

While my recollection of my aquatic biology classes would urge me to nominate algae, I don't have any good data, and the mechanism for carbon sequestrtaion in the ocean is more complex than just biological uptake;possible negative effects of adding CO2 to the ocean include acidification, biological conversion to methane, changes in dominant organisms/ populations, changes carbonate balance and there are probably another thousand or so interactions I couldn't name but could probably find given time and a library rights.

milo

I would suspect that fast-growing plants would sequester more carbon dioxide than slower-growing plants.

Generally it is variable and depends on the local growing conditions. Obviously what is required for Carbon sequestration is a large fast growing deciduous trees that live long in your local area.

There are many local studies on a few species. I have not found any compilation of all the studies but here is a local study that checked the local forests.

Here is a great article to help understand the complexities of the question