SOME ASPECTS OF ACCUMULATED CARBON IN FEW BRYOPHYTE- DOMINATED ECOSYSTEMS: A BRIEF MECHANISTIC OVERVIEW Mahesh Kumar SINGH Department of Botany and Plant.

SOME ASPECTS OF ACCUMULATED CARBON IN FEW BRYOPHYTE-DOMINATED ECOSYSTEMS: A BRIEF MECHANISTIC OVERVIEW

Mahesh Kumar SINGHDepartment of Botany and Plant PhysiologyFaculty of Agriculture and Environmental Sciences, Szent István UniversityGödöllő, Hungary

Carbon Budget

There is growing consensus within scientific community that increases in atmospheric methane (CH4) and carbon dioxide (CO2) are enhancing the earth’s natural greenhouse effect.

Because of the potential effects of these gases on global energy budget and future climate, there is an urgent need to quantify terrestrial sources and sinks of carbon.

ACCUMULATED CARBON

Understanding the rate of carbon accumulation has become more important in estimating the amount of carbon reserves and in terms of their relevance to climate change, CO2 sequestration and global warming.

Bryophyte are the primary and most important form of carbon storage in many ecosystems.

Biology of Bryophyte

Non-vascular land plants Generally known as “amphibians of plant kingdom”, mostly land

dwellers but some are aquatic e.g. Riccia fluitans, Ricciocarpus natans, Sphagnum, Riella etc.

STORED CARBON IN BRYOPHYTE

There is more carbon stored in sphagnum and sphagnum litter (150×1012g) than in any other genus of plants, vascular or non-vascular

Since the end of last glacial period, the soils of the northern latitudes have served as a reservoir for terrestrial carbon and northern peatlands alone may contain two to three times the amount of carbon stored in tropical rainforests

The majority of the carbon has been frozen in permafrost soils and sequestered from atmospheric circulation for thousands of years. On a warming planet, this carbon represents a “ticking time bomb” that could rapidly decompose and increase the amount of CO2 in the

atmosphere by as much as 50%

Stored Carbon and its pattern in various

bryophyte-dominated ecosystems Carbon accumulation= net primary production- decomposition

(stored carbon) Tundra The largest stores of carbon in arctic ecosystems are in tussock

tundra (29.1 PgC; 1 Pg= 1015 g) and wet sedge tundra (14.4 PgC) As much as 95% of the carbon in tundra ecosystems is bound in

dead organic matter as peat Until recently, tundra ecosystems were considered to be net sinks

for carbon on the order of 0.1 to 0.3 PgC yr-1 Increases in air and soil temperature may have already converted

large regions of tundra from net sinks to net sources of CO2

Tundra Ecosystem

Boreal Forests Although boreal forests cover a little less than 17% of the earths

land surface, they contain more than one-third of all soil carbon (625 PgC; 1 Pg= 1015 g) and currently function as a net carbon sink of 0.7 Gt C yr-1

Peatands Peatlands play an unique role in the terrestrial carbon cycle

because they sequester the major greenhouse gas, CO2, as peat. Boreal and subarctic peatlands cover nearly 3.5 million km2 of the earths land surface and stores 300-455 PgC. These peatlands may alone contains 2-3 times the amount of carbon stored in tropical rainforest.

Global Distribution of Peatlands

Tropical Rain Forest, Temperate Coniferous Forest and Grasslands

Bryophytes are a prominent feature of many forest and grassland types, where they can make an important contribution to carbon balance. Tropical montane rain forest, because of their complexity and variety of microhabitats, usually harbors a rich diversity of bryophytes.

Similarly, bryophytes in the temperate forest and grasslands are thought to be an important carbon sink.

Global Distribution of Tropical Rain Forest

Global Distribution of Forest

Global Distribution of Grasslands

Vegetation type Biomass (kg dry wt. m-2)

Carbon content (kg dry wt. m-2)

Temperate Grassland

0.87 0.39

Coniferous forest 26.2 11.8

Tropical montane rain forest

40.0 22.0

Total bryophyte biomass (kg dry weight m-2) and bryophyte carbon content (kg m-2) in different types of forest and grassland vegetation (Singh et al. 2005)

Conclusion

Since the end of last glacial period, bryophyte-dominated served as a reservoir for terrestrial carbon. The long time-scales over which these carbon-rich bryophyte-dominated ecosystems have developed means that recovery following major disturbance require centuries or millennia. This brief overview focuses on the importance of bryophyte-dominated ecosystems in global carbon budget because of enormous amount of carbon accumulated in bryophytes in all major ecosystems around the world.

Acknowledgements

This paper was elaborated with kind support of projects: Hungarian-Indian Intergovernmental Science Project (TÉT IND- 11/2001) and Hungarian Ministry of Environmental Protection and Hydrology, Hungarian Academy of Sciences Project (KVvM-MTA- 910009) is greatly acknowledged.

Thank you for your attention

Mahesh Kumar Singh