Gesine Mollenhauer
Biographic Data
| ID | 4456860 |
|---|---|
| NAME | Gesine Mollenhauer |
| GIVEN NAMES | Gesine |
| FAMILY NAME | Mollenhauer |
| SIGNATURE | MOLLENHAUER G |
| AFFILIATIONS | Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung |
| ORCID | 0000-0001-5138-564X |
| VERIFIED | Yes |
| TOTAL WORKS | 10 |
| TOTAL CITATIONS | 10 |
| AUTHOR COUNT | 10 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2005 |
| LATEST PUBLICATION YEAR | 2025 |
| H-INDEX | 2 |
Radiocarbon measurements of dissolved inorganic carbon (DIC) in sediment porewater and seawater at AWI Micadas
Radiocarbon ( 14 C) measurements on dissolved inorganic carbon (DIC) are a powerful tool to trace water masses and carbon cycling in the ocean. Existing methodologies to determine the 14 C content of seawater DIC requires large volumes of sample (usually >100 mL) and specialized graphitization techniques to achieve the accuracy and precision needed for meaningful data interpretation. The advancement of the CO 2 gas ionization accelerator mass spe…
The Impact of Leaching on Radiocarbon Ages of Small-Sized Foraminifera Samples
Reliable radiocarbon ( 14 C) ages of foraminifera are a prerequisite to generate robust high-resolution age-depth models or to obtain precise understanding of past carbon cycle dynamics. With the advance of small-scale 14 C measurements, instrumental precision and levels of contamination (extraneous carbon introduced during sample pretreatment or analysis) became increasingly important to consider. To reduce the effect of carbon contamination, an…
Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes
Arctic warming is causing ancient perennially frozen ground (permafrost) to thaw, resulting in ground collapse, and reshaping of landscapes. This threatens Arctic peoples' infrastructure, cultural sites, and land-based natural resources. Terrestrial permafrost thaw and ongoing intensification of hydrological cycles also enhance the amount and alter the type of organic carbon (OC) delivered from land to Arctic nearshore environments. These changes…
Seasonal nitrogen fluxes of the Lena River Delta
The Arctic is nutrient limited, particularly by nitrogen, and is impacted by anthropogenic global warming which occurs approximately twice as fast compared to the global average. Arctic warming intensifies thawing of permafrost-affected soils releasing their large organic nitrogen reservoir. This organic nitrogen reaches hydrological systems, is remineralized to reactive inorganic nitrogen, and is transported to the Arctic Ocean via large rivers.…
Marine Organic Carbon and Radiocarbon—present and Future Challenges
We discuss present and developing techniques for studying radiocarbon in marine organic carbon (C). Bulk DOC (dissolved organic C) Δ 14 C measurements reveal information about the cycling time and sources of DOC in the ocean, yet they are time consuming and need to be streamlined. To further elucidate the cycling of DOC, various fractions have been separated from bulk DOC, through solid phase extraction of DOC, and ultrafiltration of high and low…
C Blank Assessment in Small-Scale Compound-Specific Radiocarbon Analysis of Lipid Biomarkers and Lignin Phenols
Compound-specific radiocarbon ( 14 C) dating often requires working with small samples of 14 C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n -alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6–151 μgC) of n -alkanoic acids and lignin phenols obtained from standard materials with known F 14 C values. Each compound class was extracted from two standard mate…
Permafrost-carbon mobilization in Beringia caused by deglacial meltwater runoff, sea-level rise and warming
During the last deglaciation (18–8 kyr BP), shelf flooding and warming presumably led to a large-scale decomposition of permafrost soils in the mid-to-high latitudes of the Northern Hemisphere. Microbial degradation of old organic matter released from the decomposing permafrost potentially contributed to the deglacial rise in atmospheric CO 2 and also to the declining atmospheric radiocarbon contents (Δ 14 C). The significance of permafrost for t…
Holocene sea-surface temperature variability in the Chilean fjord region
Here we provide three new Holocene (11–0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50–53°S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day SSTs except for the past ~ 0.6 cal ka BP. However, they do not exhibit an early Holocene temperature optim…
Palynological evidence for climatic and oceanic variability off NW Africa during the late Holocene
Pollen and organic-walled dinoflagellate cyst assemblages from core GeoB 9503-5 retrieved from the mud-belt (∼ 50 m water depth) off the Senegal River mouth have been analyzed to reconstruct short-term palaeoceanographic and palaeoenvironmental changes in subtropical NW Africa during the time interval from ca. 4200 to 1200 cal yr BP. Our study emphasizes significant coeval changes in continental and oceanic environments in and off Senegal and sho…
Radiocarbon Dating of Alkenones from Marine Sediments
We evaluate potential process blanks associated with radiocarbon measurement of microgram to milligram quantities of alkenones at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Two strategies to constrain the contribution of blanks to alkenone 14 C dates were followed: 1) dating of samples of known age and 2) multiple measurements of identical samples. We show that the potential contamination associated with the proc…
C Blank Assessment in Small-Scale Compound-Specific Radiocarbon Analysis of Lipid Biomarkers and Lignin Phenols
Compound-specific radiocarbon ( 14 C) dating often requires working with small samples of 14 C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n -alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6–151 μgC) of n -alkanoic acids and lignin phenols obtained from standard materials with known F 14 C values. Each compound class was extracted from two standard mate…
Radiocarbon Dating of Alkenones from Marine Sediments
We evaluate potential process blanks associated with radiocarbon measurement of microgram to milligram quantities of alkenones at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Two strategies to constrain the contribution of blanks to alkenone 14 C dates were followed: 1) dating of samples of known age and 2) multiple measurements of identical samples. We show that the potential contamination associated with the proc…
Seasonal nitrogen fluxes of the Lena River Delta
The Arctic is nutrient limited, particularly by nitrogen, and is impacted by anthropogenic global warming which occurs approximately twice as fast compared to the global average. Arctic warming intensifies thawing of permafrost-affected soils releasing their large organic nitrogen reservoir. This organic nitrogen reaches hydrological systems, is remineralized to reactive inorganic nitrogen, and is transported to the Arctic Ocean via large rivers.…
Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes
Arctic warming is causing ancient perennially frozen ground (permafrost) to thaw, resulting in ground collapse, and reshaping of landscapes. This threatens Arctic peoples' infrastructure, cultural sites, and land-based natural resources. Terrestrial permafrost thaw and ongoing intensification of hydrological cycles also enhance the amount and alter the type of organic carbon (OC) delivered from land to Arctic nearshore environments. These changes…
Radiocarbon Dating of Alkenones from Marine Sediments
We evaluate potential process blanks associated with radiocarbon measurement of microgram to milligram quantities of alkenones at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Two strategies to constrain the contribution of blanks to alkenone 14 C dates were followed: 1) dating of samples of known age and 2) multiple measurements of identical samples. We show that the potential contamination associated with the proc…
Palynological evidence for climatic and oceanic variability off NW Africa during the late Holocene
Pollen and organic-walled dinoflagellate cyst assemblages from core GeoB 9503-5 retrieved from the mud-belt (∼ 50 m water depth) off the Senegal River mouth have been analyzed to reconstruct short-term palaeoceanographic and palaeoenvironmental changes in subtropical NW Africa during the time interval from ca. 4200 to 1200 cal yr BP. Our study emphasizes significant coeval changes in continental and oceanic environments in and off Senegal and sho…
Holocene sea-surface temperature variability in the Chilean fjord region
Here we provide three new Holocene (11–0 cal ka BP) alkenone-derived sea surface temperature (SST) records from the southernmost Chilean fjord region (50–53°S). SST estimates may be biased towards summer temperature in this region, as revealed by a large set of surface sediments. The Holocene records show consistently warmer than present-day SSTs except for the past ~ 0.6 cal ka BP. However, they do not exhibit an early Holocene temperature optim…
Permafrost-carbon mobilization in Beringia caused by deglacial meltwater runoff, sea-level rise and warming
During the last deglaciation (18–8 kyr BP), shelf flooding and warming presumably led to a large-scale decomposition of permafrost soils in the mid-to-high latitudes of the Northern Hemisphere. Microbial degradation of old organic matter released from the decomposing permafrost potentially contributed to the deglacial rise in atmospheric CO 2 and also to the declining atmospheric radiocarbon contents (Δ 14 C). The significance of permafrost for t…
C Blank Assessment in Small-Scale Compound-Specific Radiocarbon Analysis of Lipid Biomarkers and Lignin Phenols
Compound-specific radiocarbon ( 14 C) dating often requires working with small samples of 14 C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n -alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6–151 μgC) of n -alkanoic acids and lignin phenols obtained from standard materials with known F 14 C values. Each compound class was extracted from two standard mate…
Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes
Arctic warming is causing ancient perennially frozen ground (permafrost) to thaw, resulting in ground collapse, and reshaping of landscapes. This threatens Arctic peoples' infrastructure, cultural sites, and land-based natural resources. Terrestrial permafrost thaw and ongoing intensification of hydrological cycles also enhance the amount and alter the type of organic carbon (OC) delivered from land to Arctic nearshore environments. These changes…
Seasonal nitrogen fluxes of the Lena River Delta
The Arctic is nutrient limited, particularly by nitrogen, and is impacted by anthropogenic global warming which occurs approximately twice as fast compared to the global average. Arctic warming intensifies thawing of permafrost-affected soils releasing their large organic nitrogen reservoir. This organic nitrogen reaches hydrological systems, is remineralized to reactive inorganic nitrogen, and is transported to the Arctic Ocean via large rivers.…
Marine Organic Carbon and Radiocarbon—present and Future Challenges
We discuss present and developing techniques for studying radiocarbon in marine organic carbon (C). Bulk DOC (dissolved organic C) Δ 14 C measurements reveal information about the cycling time and sources of DOC in the ocean, yet they are time consuming and need to be streamlined. To further elucidate the cycling of DOC, various fractions have been separated from bulk DOC, through solid phase extraction of DOC, and ultrafiltration of high and low…
The Impact of Leaching on Radiocarbon Ages of Small-Sized Foraminifera Samples
Reliable radiocarbon ( 14 C) ages of foraminifera are a prerequisite to generate robust high-resolution age-depth models or to obtain precise understanding of past carbon cycle dynamics. With the advance of small-scale 14 C measurements, instrumental precision and levels of contamination (extraneous carbon introduced during sample pretreatment or analysis) became increasingly important to consider. To reduce the effect of carbon contamination, an…
Radiocarbon measurements of dissolved inorganic carbon (DIC) in sediment porewater and seawater at AWI Micadas
Radiocarbon ( 14 C) measurements on dissolved inorganic carbon (DIC) are a powerful tool to trace water masses and carbon cycling in the ocean. Existing methodologies to determine the 14 C content of seawater DIC requires large volumes of sample (usually >100 mL) and specialized graphitization techniques to achieve the accuracy and precision needed for meaningful data interpretation. The advancement of the CO 2 gas ionization accelerator mass spe…
Geology (7 works) · Geology and Paleoclimatology Research (6 works) · Oceanography (6 works) · Carbon fibers (5 works) · Chemistry (5 works) · Environmental Science (5 works) · Isotope Analysis in Ecology (5 works) · Radiocarbon dating (5 works) · Environmental Chemistry (4 works) · Geology (4 works)