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The large A mazonian peatland carbon sink in the subsiding P astaza‐ M arañón foreland basin, P eru
Author(s) -
Lähteenoja Outi,
Reátegui Yully Rojas,
Räsänen Matti,
Torres Dennis Del Castillo,
Oin Markku,
Page Susan
Publication year - 2012
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2011.02504.x
Subject(s) - peat , foreland basin , sink (geography) , carbon sink , environmental science , geology , structural basin , environmental chemistry , hydrology (agriculture) , chemistry , ecology , climate change , geomorphology , biology , geography , oceanography , cartography , geotechnical engineering
The carbon ( C ) dynamics of tropical peatlands can be of global importance, because, particularly in S outheast A sia, they are the source of considerable amounts of C released to the atmosphere as a result of land‐use change and fire. In contrast, the existence of tropical peatlands in A mazonia has been documented only recently. According to a recent study, the 120 000 km 2 subsiding P astaza‐ M arañón foreland basin in P eruvian A mazonia harbours previously unstudied and up to 7.5 m thick peat deposits. We studied the role of these peat deposits as a C reserve and sink by measuring peat depth, radiocarbon age and peat and C accumulation rates at 5–13 sites. The basal ages varied from 1975 to 8870 cal yr bp , peat accumulation rates from 0.46 to 9.31 mm yr −1 and C accumulation rates from 28 to 108 g m −2 yr −1 . The total peatland area and current peat C stock within the area of two studied satellite images were 21 929 km 2 and 3.116 Gt (with a range of 0.837–9.461 Gt). The C stock is 32% (with a range of 8.7–98%) of the best estimate of the S outh A merican tropical peatland C stock and 3.5% (with a range of 0.9–10.7%) of the best estimate of the global tropical peatland C stock. The whole P astaza‐ M arañón basin probably supports about twice this peatland area and peat C stock. In addition to their contemporary geographical extent, these peatlands probably also have a large historical (vertical) extension because of their location in a foreland basin characterized by extensive river sedimentation, peat burial and subsidence for most of the Q uaternary period. Burial of peat layers in deposits of up to 1 km thick Q uaternary river sediments removes C from the short‐term C cycle between the biosphere and atmosphere, generating a long‐term C sink.