(Table S1) N15 isotope ratios, age determination and accumulation rates of sediment core HLY02-02-17
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
2014
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| _version_ | 1867171825006411776 |
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| author | Brunelle, Brigitte G Sigman, Daniel M Cook, Mea S Keigwin, Lloyd D Haug, Gerald H Plessen, Birgit Schettler, Georg Jaccard, Samuel L |
| author_facet | Brunelle, Brigitte G Sigman, Daniel M Cook, Mea S Keigwin, Lloyd D Haug, Gerald H Plessen, Birgit Schettler, Georg Jaccard, Samuel L |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | In a piston core from the central Bering Sea, diatom microfossil-bound N isotopes and the concentrations of opal, biogenic barium, calcium carbonate, and organic N are measured over the last glacial/interglacial cycle. Compared to the interglacial sections of the core, the sediments of the last ice age are characterized by 3 per mil higher diatom-bound d15N, 70 wt % lower opal content and 1200 ppm lower biogenic barium. Taken together and with constraints on sediment accumulation rate, these results suggest a reduced supply of nitrate to the surface due to stronger stratification of the upper water column of the Bering Sea during glacial times, with more complete nitrate consumption resulting from continued iron supply through atmospheric deposition. This finding extends the body of evidence for a pervasive link between cold climates and polar ocean stratification. In addition, we hypothesize that more complete nutrient consumption in the glacial age subarctic Pacific contributed to the previously observed ice age reduction in suboxia and denitrification in the eastern tropical North Pacific by lowering the nutrient content of the intermediate-depth water formed in the subpolar North Pacific. In the deglacial interval of the Bering Sea record, two apparent peaks in export productivity are associated with maxima in diatom-bound and bulk sediment d15N. The high d15N in these intervals may have resulted from greater surface nutrient consumption during this period. However, the synchroneity of the deglacial peaks in the Bering Sea with similar bulk sediment d15N changes in the eastern Pacific margin and the presence of sediment lamination within the Bering Sea during the deposition of the productivity peaks raise the possibility that both regional and local denitrification worked to raise the d15N of the nitrate feeding Bering Sea surface waters at these times. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_833622 |
| institution | PANGAEA |
| language | en |
| publishDate | 2014 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table S1) N15 isotope ratios, age determination and accumulation rates of sediment core HLY02-02-17 Brunelle, Brigitte G Sigman, Daniel M Cook, Mea S Keigwin, Lloyd D Haug, Gerald H Plessen, Birgit Schettler, Georg Jaccard, Samuel L Accumulation rate, barium; Accumulation rate, calcium; Accumulation rate, mass; Accumulation rate, opal; AGE; Age, 14C AMS; Age, 14C calibrated; Age, dated; Age, dated, standard deviation; Aluminium; Barium; Barium, biogenic; Calcium carbonate; Calendar age, maximum/old; Calendar age, minimum/young; DEPTH, sediment/rock; HEA02; Healy; HLY0202; HLY02-02-17; JPC; Jumbo Piston Core; Neogloboquadrina pachyderma sinistral, δ18O; Nitrogen, total; Normalized; North Pacific Ocean; Opal, biogenic silica; Uvigerina sp., δ18O; δ15N; δ15N, bulk sediment In a piston core from the central Bering Sea, diatom microfossil-bound N isotopes and the concentrations of opal, biogenic barium, calcium carbonate, and organic N are measured over the last glacial/interglacial cycle. Compared to the interglacial sections of the core, the sediments of the last ice age are characterized by 3 per mil higher diatom-bound d15N, 70 wt % lower opal content and 1200 ppm lower biogenic barium. Taken together and with constraints on sediment accumulation rate, these results suggest a reduced supply of nitrate to the surface due to stronger stratification of the upper water column of the Bering Sea during glacial times, with more complete nitrate consumption resulting from continued iron supply through atmospheric deposition. This finding extends the body of evidence for a pervasive link between cold climates and polar ocean stratification. In addition, we hypothesize that more complete nutrient consumption in the glacial age subarctic Pacific contributed to the previously observed ice age reduction in suboxia and denitrification in the eastern tropical North Pacific by lowering the nutrient content of the intermediate-depth water formed in the subpolar North Pacific. In the deglacial interval of the Bering Sea record, two apparent peaks in export productivity are associated with maxima in diatom-bound and bulk sediment d15N. The high d15N in these intervals may have resulted from greater surface nutrient consumption during this period. However, the synchroneity of the deglacial peaks in the Bering Sea with similar bulk sediment d15N changes in the eastern Pacific margin and the presence of sediment lamination within the Bering Sea during the deposition of the productivity peaks raise the possibility that both regional and local denitrification worked to raise the d15N of the nitrate feeding Bering Sea surface waters at these times. |
| title | (Table S1) N15 isotope ratios, age determination and accumulation rates of sediment core HLY02-02-17 |
| topic | Accumulation rate, barium; Accumulation rate, calcium; Accumulation rate, mass; Accumulation rate, opal; AGE; Age, 14C AMS; Age, 14C calibrated; Age, dated; Age, dated, standard deviation; Aluminium; Barium; Barium, biogenic; Calcium carbonate; Calendar age, maximum/old; Calendar age, minimum/young; DEPTH, sediment/rock; HEA02; Healy; HLY0202; HLY02-02-17; JPC; Jumbo Piston Core; Neogloboquadrina pachyderma sinistral, δ18O; Nitrogen, total; Normalized; North Pacific Ocean; Opal, biogenic silica; Uvigerina sp., δ18O; δ15N; δ15N, bulk sediment |
| url | https://doi.org/10.1594/PANGAEA.833622 |