A landscape perspective of Holocene organic carbon cycling in coastal SW Greenland lake-catchments

Anderson, Nicholas; Leng, Melanie J.; Osburn, Christopher L.; Fritz, Sherilyn C.; Law, Antonia; McGowan, Suzanne

doi:10.1016/j.quascirev.2018.09.006

Cited by 15 publications

(16 citation statements)

References 52 publications

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“…Stable carbon isotope values and C:N values on solids were measured in multiple laboratories from 2009 to 2014, however comparable methodologies for solid samples using elemental analysis (EA) coupled to isotope ratio mass spectrometers (IRMS) were conducted. Solid sediment samples measured via EA‐IRMS were calibrated with acetanilide for concentrations and normalized against IAEA and NIST‐traceable stable isotope standards for δ 13 C values (Anderson et al ).…”

Section: Methodsmentioning

confidence: 99%

Stable isotopes reveal independent carbon pools across an Arctic hydro‐climatic gradient: Implications for the fate of carbon in warmer and drier conditions

Osburn

Anderson

Leng

et al. 2019

Limnol Oceanogr Letters

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Arctic lakes are poised for substantial changes to their carbon (C) cycles in the near future. Autochthonous processes in lakes which consume inorganic C and create biomass that can be sequestered in sediments are accompanied by allochthonous inputs of organic matter from the surrounding watershed. Both C sources can be mineralized and degassed as CO2, but also become recalcitrant and accumulate in pelagic waters. Using stable carbon isotope (δ13C) values and elemental ratios as geochemical proxies, we investigated diverse organic matter sources to lakes located across a hydro‐climatic gradient in Southwest Greenland. Particulate organic matter (POM) and sediments were clearly of autochthonous algal origin, while dissolved organic matter (DOM) was a mix between autochthonous macrophytes and allochthonous watershed sources. Our results imply that a warmer and drier Arctic will lead to decoupled C pools: a water column dominated by increasingly autochthonous, macrophytic DOM, and sediments dominated by autochthonous algal POM.

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Section: Methodsmentioning

confidence: 99%

Stable isotopes reveal independent carbon pools across an Arctic hydro‐climatic gradient: Implications for the fate of carbon in warmer and drier conditions

Osburn

Anderson

Leng

et al. 2019

Limnol Oceanogr Letters

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“…Previously, the changing abundance of purple sulphur bacteria (PSB) at Braya Sø has been inferred from the variable concentration of the carotenoid okenone in the lake sediment (see [34]). Unfortunately, pigments were not measured on the sediment cores used in this study The organic C flux was calculated as in previous studies [45] and at SS4 the ephippia accumulation rate was estimated as the total number of ephippia in a 1-cm sediment slice divided by the linear sediment accumulation rate (yrs cm -1 ).…”

Section: Sediment Sampling and Analysismentioning

confidence: 99%

Centennial clonal stability of asexualDaphniain Greenland lakes despite climate variability

Dane

Anderson

Osburn

et al. 2020

Preprint

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Climate and environmental condition drive biodiversity at many levels of biological organisation, from populations to ecosystems. Combined with palaeoecological reconstructions, palaeogenetic information on resident populations provides novel insights into evolutionary trajectories and genetic diversity driven by environmental variability. While temporal observations of changing genetic structure are often made of sexual populations, little is known about how environmental change affects the long-term fate of asexual lineages. Here, we provide information on obligately asexual, triploid Daphnia populations from three Arctic lakes in West Greenland through the past 200-300 years to test the impact of a changing environment on the temporal and spatial population genetic structure. The contrasting ecological state of the lakes, specifically regarding salinity and habitat structure may explain the observed lake-specific clonal composition over time. Palaeolimnological reconstructions show considerable environmental fluctuations since 1700 (the end of the Little Ice Age), but the population genetic structure in two lakes was almost unchanged with at most two clones per time period. Their local populations were strongly dominated by a single clone that has persisted for 250-300 years. We discuss three possible explanations for the apparent population genetic stability: (1) the persistent clones are general purpose genotypes that thrive under broad environmental conditions, (2) clonal lineages evolved subtle genotypic differences that are unresolved by microsatellite markers, or (3) epigenetic modifications allow for clonal adaptation to changing environmental conditions. Our results will motivate research into the mechanisms of adaptation in these populations, as well as their evolutionary fate in the light of accelerating climate change in the polar regions.

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“…The carbon (C) stored and cycled in permafrost, soils and lake sediments of Arctic landscapes is a vital component of the terrestrial C budget (Hugelius et al, 2014;Anderson et al, 2019), but Arctic ecosystems are changing rapidly (Saros et al, 2019). Climate warming in Arctic regions (Smol and Douglas, 2007) can change the ecosystem structure of catchments and lakes with probable implications for landscape-scale C cycling (Anderson et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Palaeoenvironmental records from lakes integrate carbon from the lake and catchment and allow the reconstruction of variability of C cycling on timescales that would otherwise be unobtainable (Leavitt et al, 1989(Leavitt et al, , 2009. Palaeolimnology of Arctic lakes can be used to help estimate C burial rates over the Holocene (Anderson et al, 2009(Anderson et al, , 2019 and to understand how lakes in different regions process terrestrial OM (McGowan et al, 2018). Investigations of carbon cycling across the transition between the cooler Little Ice Age (LIA) and warmer recent conditions in the Arctic provide a way of understanding how Arctic systems respond to climate change.…”

Section: Introductionmentioning

confidence: 99%

Anthropocene climate warming enhances autochthonous carbon cycling in an upland Arctic lake, Disko Island, West Greenland

et al. 2021

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Abstract. The Arctic is rapidly changing, disrupting biogeochemical cycles and the processing, delivery and sedimentation of carbon (C), in linked terrestrial–aquatic systems. In this investigation, we coupled a hydrogeomorphic assessment of catchment soils, sediments and plants with a recent lake sediment sequence to understand the source and quality of organic carbon present in three Arctic upland lake catchments on Disko Island, located just south of the low–high Arctic transition zone. This varied permafrost landscape has exposed soils with less vegetation cover at higher altitudes, and lakes received varying amounts of glacial meltwater inputs. We provide improved isotope and biomarker source identifications for palaeolimnological studies in high-latitude regions, where terrestrial vegetation is at or close to its northerly and altitudinal range limit. The poorly developed catchment soils lead to lake waters with low dissolved organic carbon (DOC) concentrations (≤1.5 mg L−1). Sedimentary carbon/nitrogen (C/N) ratios, the C isotope composition of organic matter (δ13Corg) and biomarker ratios (n-alkanes, n-alkanols, n-alkanoic acids and sterols) showed that sedimentary organic matter (OM) in these lakes is mostly derived from aquatic sources (algae and macrophytes). We used a 210Pb-dated sediment core to determine how carbon cycling in a lake–catchment system (Disko 2) had changed over recent centuries. Recent warming since the end of the Little Ice Age (LIA∼1860 CE), which accelerated after ca. 1950, led to melt of glacier ice and permafrost, releasing nutrients and DOC to the lake and stimulating pronounced aquatic algal production, as shown by a >10-fold increase in β-carotene, indicative of a major regime shift. We also demonstrate that recent increases in catchment terrestrial vegetation cover contributed to the autochthonous response. Our findings highlight that in Arctic lakes with sparsely developed catchment vegetation and soils, recent Anthropocene warming results in pronounced changes to in-lake C processing and the deposition of more reactive, predominately autochthonous C, when compared with extensively vegetated low-Arctic systems.

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A landscape perspective of Holocene organic carbon cycling in coastal SW Greenland lake-catchments

Cited by 15 publications

References 52 publications

Stable isotopes reveal independent carbon pools across an Arctic hydro‐climatic gradient: Implications for the fate of carbon in warmer and drier conditions

Stable isotopes reveal independent carbon pools across an Arctic hydro‐climatic gradient: Implications for the fate of carbon in warmer and drier conditions

Centennial clonal stability of asexualDaphniain Greenland lakes despite climate variability

Anthropocene climate warming enhances autochthonous carbon cycling in an upland Arctic lake, Disko Island, West Greenland

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