Temporal patterns of dissolved organic matter biodegradability are similar across three rivers of varying size

Coble, Ashley A.; Marcarelli, Amy; Kane, Evan S.; Toczydlowski, David; Stottlemyer, Robert

doi:10.1002/2015jg003218

Cited by 19 publications

(24 citation statements)

References 78 publications

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“…Streams are not simply a conduit from soils to oceans; within-system processes can also alter the composition of DOM and potentially its bioavailability (Cole et al, 2007;Wiegner et al, 2009;Coble et al, 2016). Processing and transport along the hydrological path alters the composition of DOM through microbial processing, photodegradation, and autochthonous production, and these changes affect the degradation of DOM further downstream (Kaplan and Bott, 1982;Larson et al, 2007;Coble et al, 2016;Fasching et al, 2019). Transformations both within and outside freshwater systems can differ largely and thus may have different consequences for DOM composition and bioavailability (Stutter and Cains, 2016).…”

Section: Introductionmentioning

confidence: 99%

Synchronous Biodegradability and Production of Dissolved Organic Matter in Two Streams of Varying Land Use

2020

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In aquatic ecosystems, dissolved organic matter (DOM) composition is driven by land use, microbial activity, and seasonal variation in hydrology and water temperature, and, in turn, its microbial bioavailability is expected to vary due to differences in its composition. It is commonly assumed that DOM of terrestrial origin is resistant to microbial activity because it is composed of more complex aromatic compounds. However, the effect of DOM sources on the microbial reworking and degradation of the DOM pool remains debated. We performed laboratory incubation experiments to examine how temporal changes in DOM composition influence its microbial biodegradability in two contrasting streams (agricultural and forested) in southern Ontario, Canada. Despite a more allochthonous-like DOM signature in the forest stream and a more autochthonous-like DOM signature in the agriculture stream, we found that biodegradation and production of DOC were the same in both streams and synchronous throughout the sampling period. However, the initial DOM composition impacted how the DOM pool changed upon degradation. During the incubations, both autochthonous-like and allochthonous-like fractions of the DOM pool increased. We also found that a greater change in DOM composition during the incubations induced higher degradation of carbon. Finally, temporal variation in DOC biodegradation and production over time or across streams was not related to DOM composition, although there was a significant relationship between BDOC and nutrient concentrations in the agriculture stream. This observation potentially challenges the notion that DOM origin predicts its bioavailability and suggests that broad environmental factors shape DOC consumption and production in aquatic ecosystems. More research is needed to better understand the drivers of microbial biodegradability in streams, as this ultimately determines the fate of DOM in aquatic ecosystems.

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Section: Introductionmentioning

confidence: 99%

Synchronous Biodegradability and Production of Dissolved Organic Matter in Two Streams of Varying Land Use

2020

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“…; Coble, Marcarelli, Kane, Stottlemyer, et al. ) (Figure ). Residence time is also an important consideration; large networks offer a longer time for DOM to be processed and degraded (Frost et al.…”

Section: When and What Do Tributaries Export Into Lake Superior?mentioning

confidence: 94%

“…; Coble, Marcarelli, Kane, and Huckins ; Coble, Marcarelli, Kane, Stottlemyer, et al. ), and a few studies on the eastern south shore (e.g., Back et al. ; Collins et al.…”

Section: How Can Emerging Technologies Be Used To Address Unknowns Inmentioning

confidence: 99%

“…For example, Calumet Watershed (1.7 km 2 ), Salmon‐Trout River (127 km 2 ), and Ontonagon River (3,400 km 2 ) exported 43%–63% of their annual dissolved organic carbon (DOC) load during the spring snowmelt freshet for the period of July 2013–June 2014 (Coble, Marcarelli, Kane, Stottlemyer, et al. ). To explore whether these patterns of export varied among years, we estimated monthly loads of DOC and nitrate from 25‐year records of discharge and nutrient concentrations from Calumet Watershed (Stottlemyer and Toczydlowski ).…”

Section: When and What Do Tributaries Export Into Lake Superior?mentioning

confidence: 99%

“…Biodegradable organic carbon (BDOC) as a percentage of the total DOC concentration, measured in three tributaries of Lake Superior (data from Coble, Marcarelli, Kane, Stottlemyer, et al. ). BDOC percentage varied widely during a late summer storm event compared to estimates during the spring freshet.…”

Section: When and What Do Tributaries Export Into Lake Superior?mentioning

confidence: 99%

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Of Small Streams and Great Lakes: Integrating Tributaries to Understand the Ecology and Biogeochemistry of Lake Superior

Marcarelli

Coble

Meingast

et al. 2018

J American Water Resour Assoc

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Research Impact Statement: Interactions between Lake Superior and its tributaries are frequently ignored, and understanding the Lake Superior ecosystem requires a nuanced consideration of these interactions in time and space.ABSTRACT: Lake Superior receives inputs from approximately 2,800 tributaries that provide nutrients and dissolved organic matter (DOM) to the nearshore zone of this oligotrophic lake. Here, we review the magnitude and timing of tributary export and plume formation in Lake Superior, how these patterns and interactions may shift with global change, and how emerging technologies can be used to better characterize tributary-lake linkages. Peak tributary export occurs during snowmelt-driven spring freshets, with additional pulses during raindriven storms. Instream processing and transformation of nitrogen, phosphorus, and dissolved organic carbon (DOC) can be rapid but varies seasonally in magnitude. Tributary plumes with elevated DOC concentration, higher turbidity, and distinct DOM character can be detected in the nearshore during times of high runoff, but plumes can be quickly transported and diluted by in-lake currents and mixing. Understanding the variability in size and load of these tributary plumes, how they are transported within the lake, and how long they persist may be best addressed with environmental sensors and remote sensing using autonomous and unmanned vehicles. The connections between Lake Superior and its tributaries are vulnerable to climate change, and understanding and predicting future changes to these valuable freshwater resources will require a nuanced and detailed consideration of tributary inputs and interactions in time and space.

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In‐lake transformations of dissolved organic matter composition in a subalpine lake do not change its biodegradability

Stadler

Ejarque

Kainz

2020

Limnology & Oceanography

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In freshwater ecosystems, dissolved organic matter (DOM) originates from terrestrial and aquatic primary production, and its microbial biodegradability is expected to vary due to differences in its biogeochemical composition. However, the interaction of various DOM sources with the aquatic microbial population remains widely debated. Here, we performed laboratory bioassays, conducted in the dark for 20 d, to examine how changes in DOM composition influence its microbial biodegradability along a hydrological continuum (i.e., lake inlet, lake layers, and lake outlet) of a subalpine lake over four seasons. Despite a predominance of terrestrial DOM and lowest initial abundance of microorganisms, the highest microbial growth rates were observed at the lake inlet (0.0076 ± 0.0011 cells mL−1 h−1) across all seasons. DOM reactivity differed more with time (seasons) than with space (sampling sites) and DOM compositional differences showed higher degradability in upper lake layers, but not at the lake outlet. Additionally, gradual humification over incubation time was observed in almost all seasons and sites. Overall, an enhanced biodegradability of DOM was not detected even though lake sites were characterized by an autochthonous, presumably labile DOM signature. However, our results highlight the potential of thriving bacteria in terrestrial‐dominated DOM environments. This observation challenges a previous hypothesis that DOM of terrestrial origin is less accessible and more recalcitrant, while emphasizing the flexible response of aquatic systems to seasonal fluctuations.

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Temporal patterns of dissolved organic matter biodegradability are similar across three rivers of varying size

Cited by 19 publications

References 78 publications

Synchronous Biodegradability and Production of Dissolved Organic Matter in Two Streams of Varying Land Use

Synchronous Biodegradability and Production of Dissolved Organic Matter in Two Streams of Varying Land Use

Of Small Streams and Great Lakes: Integrating Tributaries to Understand the Ecology and Biogeochemistry of Lake Superior

In‐lake transformations of dissolved organic matter composition in a subalpine lake do not change its biodegradability

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