Anne Karin Hufthammer | University of Bergen (original) (raw)
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Papers by Anne Karin Hufthammer
Journal of Evolutionary Biology, 2010
The Pleistocene to Holocene transition was accompanied by a worldwide extinction event affecting ... more The Pleistocene to Holocene transition was accompanied by a worldwide extinction event affecting numerous mammalian species. Several species such as the woolly mammoth and the giant deer survived this extinction wave, only to go extinct a few thousand years later during the Holocene. Another example for such a Holocene extinction is the Don-hare, Lepus tanaiticus, which inhabited the Russian plains during the late glacial. After being slowly replaced by the extant mountain hare (Lepus timidus), it eventually went extinct during the middle Holocene. Here, we report the phylogenetic relationship of L. tanaiticus and L. timidus based on a 339-basepair (bp) fragment of the mitochondrial D-loop. Phylogenetic tree- and network reconstructions do not support L. tanaiticus and L. timidus being different species. Rather, we suggest that the two taxa represent different morphotypes of a single species and the extinction of ‘L. tanaiticus’ represents the disappearance of a local morphotype rather than the extinction of a species.
In order to compare radiocarbon dates on marine and terrestrial samples, the former have to be co... more In order to compare radiocarbon dates on marine and terrestrial samples, the former have to be corrected for a marine reservoir age. We have calculated present day reservoir ages in this area by dating 22 whales collected AD 1860-1901 and 23 molluscs collected AD 1857-1926. Whales feed on pelagic organisms and will provide the reservoir age for the open ocean surface water. However, they travel large distances and integrate the reservoir ages of water masses along their way. Molluscs are stationary and monitor the sea water passing their living site. For the surface water in the N-Atlantic and Norwegian Sea we recommend to use the mean obtained for the two sets, i.e. reservoir ages of 400 +/- 40 and 375 +/- 30 years relative to tree rings of Intcal04 and British oak respectively, for the parts of the Holocene where specific time-dependent reservoir ages are not determined. The reservoir ages relative to British oak best reflects regional processes and we therefore prefer those, whereas IntCal04 ages are much more precisely determined, but dominated by trees from NW-USA in this time period. The reservoir ages for Allerod-Younger Dryas (YD) are obtained by dating parallel samples of terrestrial plant fragments and marine shells from sediment cores from the outermost western coast of Norway. The marine mud contains both plant fragments blown or washed in from adjacent land and in situ marine shells. In the earliest period (13,800-14,500 cal yrs BP) the reservoir age is 300-400 years, similar to present day values. This suggests that the exchange of CO2 between the atmosphere and the surface ocean was comparable to the present. During a short interval 13,200-13,500 cal yrs BP we found higher reservoir ages of 500-600 years coinciding with lower organic carbon content in our cores, and an inter-Allerod fluctuation seen in marine records. During the early YD the reservoir ages increased gradually from 400 to 650 years, causing a 700-14C year-long plateau, centred at 11,000 14C yrs BP, for marine dates at a time of high resolution for terrestrial dates. This may reflect increased annual sea-ice cover, reducing the rate of CO2 exchange between the atmosphere and the sea surface. But better; our dates show that the marine 14C ages decreased rapidly from 10,600 to 10,100 14C yrs BP. This is the time of the well-known 10,000 14C year plateau in terrestrial dates, and the result is that one can obtain higher resolution of calibrated marine 14C dates at the YD/Holocene transition than for terrestrial 14C dates. This presentation is based on two manuscripts that will be submitted about 1. Sept 2005: Bondevik, S., Mangerud, J., Birks, H. H., Gulliksen, S., and Reimer, P.: Late-glacial reservoir ages of surface waters in the North Atlantic. Mangerud, J., Bondevik, S., Gulliksen, S., Hufthammer, A.K., Hoisaeter, T.: Marine 14C reservoir ages for whales and molluscs from the North Atlantic.
Quaternary Science Reviews, 2006
Quaternary Science Reviews, 2010
Journal of Quaternary Science, 1996
... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-500... more ... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-5007 Bergen, Norway. Publication History. ... The newly discovered Hamnsund Interstadial above this consists of frost-weathered clay and scattered angular blocks. ...
Journal of Quaternary Science, 1996
... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-500... more ... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-5007 Bergen, Norway. Publication History. ... The newly discovered Hamnsund Interstadial above this consists of frost-weathered clay and scattered angular blocks. ...
Quaternary International, 2009
Quaternary International, 2009
Journal of Evolutionary Biology, 2010
The Pleistocene to Holocene transition was accompanied by a worldwide extinction event affecting ... more The Pleistocene to Holocene transition was accompanied by a worldwide extinction event affecting numerous mammalian species. Several species such as the woolly mammoth and the giant deer survived this extinction wave, only to go extinct a few thousand years later during the Holocene. Another example for such a Holocene extinction is the Don-hare, Lepus tanaiticus, which inhabited the Russian plains during the late glacial. After being slowly replaced by the extant mountain hare (Lepus timidus), it eventually went extinct during the middle Holocene. Here, we report the phylogenetic relationship of L. tanaiticus and L. timidus based on a 339-basepair (bp) fragment of the mitochondrial D-loop. Phylogenetic tree- and network reconstructions do not support L. tanaiticus and L. timidus being different species. Rather, we suggest that the two taxa represent different morphotypes of a single species and the extinction of ‘L. tanaiticus’ represents the disappearance of a local morphotype rather than the extinction of a species.
In order to compare radiocarbon dates on marine and terrestrial samples, the former have to be co... more In order to compare radiocarbon dates on marine and terrestrial samples, the former have to be corrected for a marine reservoir age. We have calculated present day reservoir ages in this area by dating 22 whales collected AD 1860-1901 and 23 molluscs collected AD 1857-1926. Whales feed on pelagic organisms and will provide the reservoir age for the open ocean surface water. However, they travel large distances and integrate the reservoir ages of water masses along their way. Molluscs are stationary and monitor the sea water passing their living site. For the surface water in the N-Atlantic and Norwegian Sea we recommend to use the mean obtained for the two sets, i.e. reservoir ages of 400 +/- 40 and 375 +/- 30 years relative to tree rings of Intcal04 and British oak respectively, for the parts of the Holocene where specific time-dependent reservoir ages are not determined. The reservoir ages relative to British oak best reflects regional processes and we therefore prefer those, whereas IntCal04 ages are much more precisely determined, but dominated by trees from NW-USA in this time period. The reservoir ages for Allerod-Younger Dryas (YD) are obtained by dating parallel samples of terrestrial plant fragments and marine shells from sediment cores from the outermost western coast of Norway. The marine mud contains both plant fragments blown or washed in from adjacent land and in situ marine shells. In the earliest period (13,800-14,500 cal yrs BP) the reservoir age is 300-400 years, similar to present day values. This suggests that the exchange of CO2 between the atmosphere and the surface ocean was comparable to the present. During a short interval 13,200-13,500 cal yrs BP we found higher reservoir ages of 500-600 years coinciding with lower organic carbon content in our cores, and an inter-Allerod fluctuation seen in marine records. During the early YD the reservoir ages increased gradually from 400 to 650 years, causing a 700-14C year-long plateau, centred at 11,000 14C yrs BP, for marine dates at a time of high resolution for terrestrial dates. This may reflect increased annual sea-ice cover, reducing the rate of CO2 exchange between the atmosphere and the sea surface. But better; our dates show that the marine 14C ages decreased rapidly from 10,600 to 10,100 14C yrs BP. This is the time of the well-known 10,000 14C year plateau in terrestrial dates, and the result is that one can obtain higher resolution of calibrated marine 14C dates at the YD/Holocene transition than for terrestrial 14C dates. This presentation is based on two manuscripts that will be submitted about 1. Sept 2005: Bondevik, S., Mangerud, J., Birks, H. H., Gulliksen, S., and Reimer, P.: Late-glacial reservoir ages of surface waters in the North Atlantic. Mangerud, J., Bondevik, S., Gulliksen, S., Hufthammer, A.K., Hoisaeter, T.: Marine 14C reservoir ages for whales and molluscs from the North Atlantic.
Quaternary Science Reviews, 2006
Quaternary Science Reviews, 2010
Journal of Quaternary Science, 1996
... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-500... more ... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-5007 Bergen, Norway. Publication History. ... The newly discovered Hamnsund Interstadial above this consists of frost-weathered clay and scattered angular blocks. ...
Journal of Quaternary Science, 1996
... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-500... more ... Correspondence: VIDAR VALEN, Department of Geology, University of Bergen, Allégaten 41, N-5007 Bergen, Norway. Publication History. ... The newly discovered Hamnsund Interstadial above this consists of frost-weathered clay and scattered angular blocks. ...
Quaternary International, 2009
Quaternary International, 2009