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

Osburn, Christopher L.; Anderson, Nicholas; Leng, Melanie J.; Barry, C.; Whiteford, Erika J.

doi:10.1002/lol2.10119

Cited by 16 publications

(20 citation statements)

References 45 publications

(71 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The lack of significant relationship between the ∆ 14 C of DOC and POC and nitrogen or dissolved O 2 , points to a relatively small control by instream primary production. However, for rivers heavily influenced by lakes, suspended algal material can be a proportionally greater source of POC and turbidity (Osburn et al, 2019). This was likely the case of the outlet of the Great Slave Lake, where POC was noticeably more recent (Δ 14 C −251‰), compared with other locations along the Mackenzie River (Figure 2b).…”

Section: Discussionmentioning

confidence: 99%

Controls on the ¹⁴C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada

Campeau

Soerensen

Martma

et al. 2020

Global Biogeochemical Cycles

View full text Add to dashboard Cite

The Mackenzie River Basin (MRB) delivers large quantities of organic carbon (OC) into the Arctic Ocean, with significant implications for the global C budgets and ocean biogeochemistry. The amount and properties of OC in the Mackenzie River's delta have been well monitored in the last decade, but the spatial variability in OC sources transported by its different tributaries is still unclear. Here we present new data on the radiocarbon (14 C) content of dissolved and particulate OC (Δ 14 C-DOC and Δ 14 C-POC) across the mainstem and major tributaries of the MRB, comprising 19 different locations, to identify factors controlling spatial patterns in riverine OC sources. The Δ 14 C-DOC and Δ 14 C-POC varied across a large range, from −179.9‰ to 62.9‰, and −728.8‰ to −9.0‰, respectively. Our data reveal a positive spatial coupling between the Δ 14 C of DOC and POC across the MRB, whereby the most 14 C-depleted waters were issued from the mountainous west bank of the MRB. This 14 C-depleted DOC and POC likely originates from a combination of petrogenic sources, connected with the presence of kerogens in the bedrock, and biogenic sources, mobilized by thawing permafrost. Our analysis also reveals intriguing relationships between Δ 14 C of DOC and POC with turbidity, water stable isotope ratio and catchment elevation, indicating that hydrology and geomorphology are key to understanding riverine OC sources in this landscape. A closer examination of the specific mechanisms giving rise to these relationships is recommended. For now, this study provides a road map of the key OC sources in this rapidly changing river basin.

show abstract

Section: Discussionmentioning

confidence: 99%

Controls on the ¹⁴C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada

Campeau

Soerensen

Martma

et al. 2020

Global Biogeochemical Cycles

View full text Add to dashboard Cite

show abstract

“…The dynamics of the various sources and sinks of DOM in aquatic systems are difficult to unravel with experiments and observations. Studies to date that attempt to quantify the relative importance of allochthonous and autochthonous sources generally use spectroscopic techniques (McKnight et al 2001), or bulk characteristics like isotope ratios (Toming et al 2013; Osburn et al 2019), all of which are techniques that integrate a vast molecular diversity.…”

mentioning

confidence: 99%

Character and environmental lability of cyanobacteria‐derived dissolved organic matter

Patriarca

Sedano-Núñez

Garcia

et al. 2020

Limnology & Oceanography

View full text Add to dashboard Cite

Autotrophic dissolved organic matter (DOM) is central to the carbon biogeochemistry of aquatic systems, and the full complexity of autotrophic DOM has not been extensively studied, particularly by high-resolution mass spectrometry (HRMS). Terrestrial DOM tends to dominate HRMS studies in freshwaters due to the propensity of such compounds to ionize by negative mode electrospray, and possibly also because ionizable DOM produced by autotrophy is decreased to low steady-state concentrations by heterotrophic bacteria. In this study, we investigated the character of DOM produced by the widespread cyanobacteria Microcystis aeruginosa using highpressure liquid chromatography-electrospray ionization-high-resolution mass spectrometry. M. aeruginosa produced thousands of detectable compounds in axenic culture. These compounds were chromatographically resolved and the majority were assigned to aliphatic formulas with a broad polarity range. We found that the DOM produced by M. aeruginosa was highly susceptible to removal by heterotrophic freshwater bacteria, supporting the hypothesis that this autotroph-derived organic material is highly labile and accordingly only seen at low concentrations in natural settings.

show abstract

“…Lakes in the Kangerlussuaq area are tightly coupled to regional climate change which influences both terrestrial landscape and in-lake aquatic processes, such as hydrological runoff, terrestrial productivity, lake levels, conductivity and DOC concentration [53]. The period covered by the genetic analyses, ~300 years, includes the end of the Little Ice Age (LIA); a period of considerable change in regional climate, with aridity and fluctuating temperatures.…”

Section: Regional Environmental Changementioning

confidence: 99%

Centennial clonal stability of asexualDaphniain Greenland lakes despite climate variability

Dane

Anderson

Osburn

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

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.

show abstract

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

Cited by 16 publications

References 45 publications

Controls on the ¹⁴C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada

Controls on the ¹⁴C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada

Character and environmental lability of cyanobacteria‐derived dissolved organic matter

Centennial clonal stability of asexualDaphniain Greenland lakes despite climate variability

Contact Info

Product

Resources

About

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

Cited by 16 publications

References 45 publications

Controls on the 14C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada

Controls on the 14C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada

Character and environmental lability of cyanobacteria‐derived dissolved organic matter

Centennial clonal stability of asexualDaphniain Greenland lakes despite climate variability

Contact Info

Product

Resources

About

Controls on the ¹⁴C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada

Controls on the ¹⁴C Content of Dissolved and Particulate Organic Carbon Mobilized Across the Mackenzie River Basin, Canada