| _version_ | 1867169092639653888 |
|---|---|
| author | Nave, Silvia Osorio Labeyrie, Laurent D Gherardi, Jeanne-Marie Caillon, Nicolas Cortijo, Elsa Kissel, Catherine Abrantes, Fatima F |
| author_facet | Nave, Silvia Osorio Labeyrie, Laurent D Gherardi, Jeanne-Marie Caillon, Nicolas Cortijo, Elsa Kissel, Catherine Abrantes, Fatima F |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | he last glacial was punctuated by several massive ice sheet surges into the North Atlantic that impacted surface water hydrology especially where icebergs melted. However, the links between variations in surface water hydrology and surface water productivity during these Heinrich events (HEs) remain uncertain. To address this issue, diatoms and organic carbon were examined across Heinrich event 1 (HE 1) and Heinrich event 4 (HE 4) in seven sediment cores spanning 40°N to 63°N latitude. Our results show low diatom abundances during HEs, consistent with decreased surface water productivity. Diatom dilution by increased sediment flux was tested by normalizing diatom abundance to a constant 230Th flux. Although the particle rain rate was enhanced during HEs, this does not explain the sharp drop in diatoms. During HE 4, surface productivity decreased at all latitudes examined, probably because of strong, year-round stratification. The same inferred changes occurred during HE 1 within the area of maximum iceberg melting. However, at northern latitudes (above 50°N) the summer insolation increase of the glacial termination drove increased surface productivity during the whole period, including HE 1. Marine organic carbon, taken as independent proxy for export production, supports the diatom data. Trends shown by the productivity proxies evolve generally in parallel with the hydrographic proxies, with an increase in productivity when sea surface temperature increases. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_833081 |
| institution | PANGAEA |
| language | en |
| publishDate | 2007 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table S1) 230Th normalized diatom fluxes through HE1 in sediment core MD95-2027 Nave, Silvia Osorio Labeyrie, Laurent D Gherardi, Jeanne-Marie Caillon, Nicolas Cortijo, Elsa Kissel, Catherine Abrantes, Fatima F -; Accumulation rate, diatoms; AGE; CALYPSO; Calypso Corer; DEPTH, sediment/rock; Diatoms, total, per unit sediment mass; IMAGES I; Marion Dufresne (1995); MD101__Campaign; MD952027; MD95-2027; Newfoundland Slope; Thorium-230, flux normalized he last glacial was punctuated by several massive ice sheet surges into the North Atlantic that impacted surface water hydrology especially where icebergs melted. However, the links between variations in surface water hydrology and surface water productivity during these Heinrich events (HEs) remain uncertain. To address this issue, diatoms and organic carbon were examined across Heinrich event 1 (HE 1) and Heinrich event 4 (HE 4) in seven sediment cores spanning 40°N to 63°N latitude. Our results show low diatom abundances during HEs, consistent with decreased surface water productivity. Diatom dilution by increased sediment flux was tested by normalizing diatom abundance to a constant 230Th flux. Although the particle rain rate was enhanced during HEs, this does not explain the sharp drop in diatoms. During HE 4, surface productivity decreased at all latitudes examined, probably because of strong, year-round stratification. The same inferred changes occurred during HE 1 within the area of maximum iceberg melting. However, at northern latitudes (above 50°N) the summer insolation increase of the glacial termination drove increased surface productivity during the whole period, including HE 1. Marine organic carbon, taken as independent proxy for export production, supports the diatom data. Trends shown by the productivity proxies evolve generally in parallel with the hydrographic proxies, with an increase in productivity when sea surface temperature increases. |
| title | (Table S1) 230Th normalized diatom fluxes through HE1 in sediment core MD95-2027 |
| topic | -; Accumulation rate, diatoms; AGE; CALYPSO; Calypso Corer; DEPTH, sediment/rock; Diatoms, total, per unit sediment mass; IMAGES I; Marion Dufresne (1995); MD101__Campaign; MD952027; MD95-2027; Newfoundland Slope; Thorium-230, flux normalized |
| url | https://doi.org/10.1594/PANGAEA.833081 |