title: Bayesian evaluation of the southern hemisphere radiocarbon offset during the holocene

authors: Hogg, Alan G.

subjects: radiocarbon

abstract: While an interhemispheric offset in atmospheric radiocarbon levels from AD 1950–950 is now well established, its existence earlier in the Holocene is less clear, with some studies reporting globally uniform 14C levels while others finding Southern Hemisphere samples older by a few decades. In this paper, we present a method for wiggle-matching Southern Hemisphere data sets against Northern Hemisphere curves, using the Bayesian calibration program OxCal 4.1 with the Reservoir Offset function accommodating a potential interhemispheric offset. The accuracy and robustness of this approach is confirmed by wiggle-matching known-calendar age sequences of the Southern Hemisphere calibration curve SHCal04 against the Northern Hemisphere curve IntCal04. We also show that 5 of 9 Holocene Southern Hemisphere data sets are capable of yielding reliable offset information. Those data sets that are accurate and precise show that interhemispheric offset levels in the Early Holocene are similar to modern levels, confirming SHCal04 as the curve of choice for calibrating Southern Hemisphere samples.

text: Bayesian evaluation of the southern hemisphere radiocarbon offset during the holocene While an interhemispheric offset in atmospheric radiocarbon levels from AD 1950–950 is now well established, its existence earlier in the Holocene is less clear, with some studies reporting globally uniform 14C levels while others finding Southern Hemisphere samples older by a few decades. In this paper, we present a method for wiggle-matching Southern Hemisphere data sets against Northern Hemisphere curves, using the Bayesian calibration program OxCal 4.1 with the Reservoir Offset function accommodating a potential interhemispheric offset. The accuracy and robustness of this approach is confirmed by wiggle-matching known-calendar age sequences of the Southern Hemisphere calibration curve SHCal04 against the Northern Hemisphere curve IntCal04. We also show that 5 of 9 Holocene Southern Hemisphere data sets are capable of yielding reliable offset information. Those data sets that are accurate and precise show that interhemispheric offset levels in the Early Holocene are similar to modern levels, confirming SHCal04 as the curve of choice for calibrating Southern Hemisphere samples.

year: 2009

title: Effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi (Basilewsky)

authors: Li, Wei

subjects: foraging success

abstract: This study aimed to evaluate the effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi. Predation on crucian carp Carassius auratus by juvenile mandarin fish was tested at five levels of turbidity combined with two light intensities, imitating daylight and night in two turbidity types. Foraging success was significantly lower in clay-induced turbidity than in algal-induced turbidity. In clay-induced turbidity trials, there was a slight but insignificant increase in foraging success of mandarin fish with increasing turbidity under lighted conditions. In algal-induced turbidity trials, there were no significant differences in foraging success of mandarin fish among turbidity levels at both light and dark levels, but at 80 NTU turbidity level, foraging success was lower than in all the other turbidity levels. There was no significant difference in foraging success at different turbidities under darkness. These results suggest that piscivory of mandarin fish is influenced by different turbidity types but is not significantly influenced by increased turbidity combined with decreased light intensity.

text: Effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi (Basilewsky) This study aimed to evaluate the effects of turbidity and light intensity on foraging success of juvenile mandarin fish Siniperca chuatsi. Predation on crucian carp Carassius auratus by juvenile mandarin fish was tested at five levels of turbidity combined with two light intensities, imitating daylight and night in two turbidity types. Foraging success was significantly lower in clay-induced turbidity than in algal-induced turbidity. In clay-induced turbidity trials, there was a slight but insignificant increase in foraging success of mandarin fish with increasing turbidity under lighted conditions. In algal-induced turbidity trials, there were no significant differences in foraging success of mandarin fish among turbidity levels at both light and dark levels, but at 80 NTU turbidity level, foraging success was lower than in all the other turbidity levels. There was no significant difference in foraging success at different turbidities under darkness. These results suggest that piscivory of mandarin fish is influenced by different turbidity types but is not significantly influenced by increased turbidity combined with decreased light intensity.

year: 2013

title: The timing of the human discovery and colonization of New Zealand

authors: Sutton, Douglas G.

abstract: In discriminating between the proposed Long, Short and Intermediate Chronologies for New Zealand prehistory, archaeologists have recently voted by a narrow majority that the human commensal, Rattus exulans, was present in New Zealand up to 2000 years BP, although the preferred date of ‘first settlement’ by people was ca 800 years BP. A recalibration of New Zealand chronometric data has resulted in reinterpretations of the date and duration of occupation on critical archaeological sites. A remodelling of the ages of the putatively earliest sites in New Zealand has shown these to indicate only a broadly defined period when settlement occurred rather than the date when New Zealand was discovered (as the Short Chronology advocates have insisted). Finally, comparisons with archaeological research on islands elsewhere in the world have brought with them recognition that the discovery, exploration, initial settlement and colonization of New Zealand by Polynesian voyagers were broadly consecutive processes. This paper reviews a range of current evidence in the context of its current theorization and affirms the Long Chronology, recognizing it as the most plausible hypothesis.

text: The timing of the human discovery and colonization of New Zealand In discriminating between the proposed Long, Short and Intermediate Chronologies for New Zealand prehistory, archaeologists have recently voted by a narrow majority that the human commensal, Rattus exulans, was present in New Zealand up to 2000 years BP, although the preferred date of ‘first settlement’ by people was ca 800 years BP. A recalibration of New Zealand chronometric data has resulted in reinterpretations of the date and duration of occupation on critical archaeological sites. A remodelling of the ages of the putatively earliest sites in New Zealand has shown these to indicate only a broadly defined period when settlement occurred rather than the date when New Zealand was discovered (as the Short Chronology advocates have insisted). Finally, comparisons with archaeological research on islands elsewhere in the world have brought with them recognition that the discovery, exploration, initial settlement and colonization of New Zealand by Polynesian voyagers were broadly consecutive processes. This paper reviews a range of current evidence in the context of its current theorization and affirms the Long Chronology, recognizing it as the most plausible hypothesis.

year: 2008