Distal volcanic impacts on peatlands: palaeoecological evidence from Alaska

Abstract

2 3Despite the fact that volcanic ash (tephra) layers are found preserved in peat 4 deposits around the world, comparatively little research has investigated the 5 impacts of distal volcanic emissions on peatlands. This study investigates the 6 impacts of several late-Holocene volcanic eruptions on five peatlands in 7 southern Alaska using a palaeoecological approach. Testate amoebae analysis, 8peat humification analysis and a basic analysis of plant macrofossil components 9were applied across 11 tephra layers. Changes in macrofossil and testate 10 amoebae assemblages occur across several of the tephra layers. The 11 humification results were unreliable because of a methodological problem, a 12 finding which may have implications for other studies using this technique. 13Redundancy analyses on testate amoebae data show statistically significant 14 changes associated with two tephras. The most likely causes of the impacts are 15 volcanic gases, acidic precipitation or tephra-derived leachates. The finding 16 that some tephras are associated with impacts whereas others are not may 17 relate to the season of the eruption or meteorological conditions at the time of 18 ash fall. These results suggest the sensitivity of peatlands and peatland 19 microbial communities to distal volcanic products and imply that changes in 20 key palaeoclimatic proxies may be caused by a mechanism independent of 21 climate change. Implications of the results for peat-based palaeoclimatic 22 studies are discussed, as are possible directions for future research.

Climatic changes since the last deglaciation inferred from a lacustrine sedimentary sequence in the eastern Nanling Mountains, south China

“…Higher HD cab values represent stronger humification intensity and vice versa. However, one problem possibly encountered with humification measurements is that we cannot exclude the possible influence of very small mineral fragments passing through the filter paper (Payne and Blackford, 2008), though the influence is not significant.…”

Humification degrees of a lacustrine sedimentary sequence as an indicator of past climatic changes in the last c. 49 000 years in South China

“…Higher HD cab represents stronger humification and vice versa. However, one problem possibly encountered with humification measurements is that one cannot exclude the possible influence of very small mineral fragments passing through the filter paper (Payne & Blackford 2008), though the influence is not significant. The sample for d 13 C org measurement was acidwashed with 5% HCl to remove possible trace amounts of carbonate carbon, rinsed with de-ionized water and oven-dried at 501C.…”

In memoriam and dedication: Richard John Payne (1978–2019)

“…Richard was an all‐round environmental scientist, but tephrochronology was one of his passions. He used tephras extensively in his PhD studies in Alaska (2002–2006) under the supervision of JJB at Queen Mary, University of London (Payne and Blackford, ; Payne et al ., ), and applied his tephra expertise to novel experimental studies in Britain, while still completing his PhD thesis (Payne and Blackford, ; Payne et al . ).…”