Dissolved organic carbon uptake in streams: A review and assessment of reach‐scale measurements

Mineau, Madeleine M.; Wollheim, W. M.; Buffam, Ishi; Findlay, Stuart E. G.; Hall, Robert O.; Hotchkiss, Erin R.; Koenig, Lauren E.; McDowell, William H.; Parr, Thomas B.

doi:10.1002/2015jg003204

Cited by 86 publications

(121 citation statements)

References 69 publications

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“…The use of highly labile monomers (e.g., acetate and glucose) and plant leachates typically overestimates the ambient v f and areal uptake ( U ) of DOC (Mineau et al, ; further discussion in Supporting Information Appendix S1). To better estimate ambient areal uptake, we adopt the methods of Mineau et al () and assume that the actively cycling carbon pool consists entirely of BDOC and that the v f estimated by labile compound additions is accurate for the labile pool. Thus, we calculate areal uptake U BDOC (mg m −2 s −1 , units reported in text as mg m −2 hr −1 ) as:

U_{BDOC} = v_{f} \times BDOC

…”

Section: Methodsmentioning

confidence: 99%

Animal‐mediated organic matter transformation: Aquatic insects as a source of microbially bioavailable organic nutrients and energy

et al. 2018

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Animal communities are essential drivers of energy and elemental flow in ecosystems. However, few studies have investigated the functional role of animals as sources of dissolved organic matter (DOM) and the subsequent utilization of that DOM by the microbial community. In a small forested headwater stream, we tested the effects of taxonomy, feeding traits, and body size on the quality and quantity of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) excreted by aquatic insects. In addition, we conducted steady‐state solute additions to estimate instream demand for labile C and compared it to the C excreted by invertebrates. Individual excretion rates and excretion composition varied with body size, taxonomy and feeding guild. The estimated average community excretion rate was 1.31 μg DOC· per mg insect dry weight (DW)−1 hr−1 and 0.33 μg DON·mg DW−1 hr‐1, and individuals excreted DON at nearly twice the rate of NH4+. This DOM was 2–5 times more bioavailable to microbial heterotrophs than ambient stream water DOM. We estimated that the insect community, conservatively, excreted 1.62 mg of bioavailable DOC·m−2 hr−1 and through steady‐state additions measured an ambient labile C demand as 3.97 ± 0.67 mg C m−2 hr−1. This suggests that insect‐mediated transformation and excretion of labile DOC could satisfy a significant fraction (40 ± 7%) of labile C demand in this small stream. Collectively, our results suggest that animal excretion plays an essential functional role in transforming organic matter into microbially bioavailable forms and may satisfy a variable but significant portion of microbial demand for labile C and N. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13242/suppinfo is available for this article.

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U_{BDOC} = v_{f} \times BDOC

…”

Section: Methodsmentioning

confidence: 99%

Animal‐mediated organic matter transformation: Aquatic insects as a source of microbially bioavailable organic nutrients and energy

et al. 2018

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“…Mechanisms affecting DOC processing at different temporal and spatial scales also hamper our quest to appraise controls on DOC processing (Lisboa et al, ; Mineau et al, ). For instance, seasonality is likely to influence stream DOC uptake, as seasonal variability is tightly related to discharge.…”

Section: Introductionmentioning

confidence: 99%

“…The few studies examining the influence of nitrogen availability on DOC uptake metrics have reached contrasting results (Bechtold et al, ; Johnson et al, ; Martí & Sabater, ; Mutschlecner et al, ). Furthermore, research assessing the effects of ambient DOM composition on DOC uptake is even scarcer (Mineau et al, ; but see Lutz et al, ). Similarly, the relationship between stream metabolism and DOC uptake at the reach scale is still poorly explored.…”

Section: Introductionmentioning

confidence: 99%

Behind the Scenes: Mechanisms Regulating Climatic Patterns of Dissolved Organic Carbon Uptake in Headwater Streams

Catalán

Casas-Ruiz

Arce

et al. 2018

Global Biogeochemical Cycles

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Large variability in dissolved organic carbon (DOC) uptake rates has been reported for headwater streams, but the causes of this variability are still not well understood. Here we assessed acetate uptake rates across 11 European streams comprising different ecoregions by using whole‐reach pulse acetate additions. We evaluated the main climatic and biogeochemical drivers of acetate uptake during two seasonal periods. Our results show a minor influence of sampling periods but a strong effect of climate and dissolved organic matter (DOM) composition on acetate uptake. In particular, mean annual precipitation explained half of the variability of the acetate uptake velocities (VfAcetate) across streams. Temperate streams presented the lowest VfAcetate, together with humic‐like DOM and the highest stream respiration rates. In contrast, higher VfAcetate were found in semiarid streams, with protein‐like DOM, indicating a dominance of reactive, labile compounds. This, together with lower stream respiration rates and molar ratios of DOC to nitrate, suggests a strong C limitation in semiarid streams, likely due to reduced inputs from the catchment. Overall, this study highlights the interplay of climate and DOM composition and its relevance to understand the biogeochemical mechanisms controlling DOC uptake in streams.

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“…, Mineau et al. ). However the average rates of mineralization of natural DOM at the soil–water interface in both streams (scaled up to the first‐order catchment) were relatively high: 22% ± 10% (Birnie) and 31% ± 15% (Cairn) under stable flows, with peaks over 50% (Demars ).…”

Section: Discussionmentioning

confidence: 99%

“…, ), which are known to be processed at a slower rate than simple organic compounds (Mineau et al. ). Many studies have also traced the flux of autochthonous DOM through to bacteria (e.g., Neely and Wetzel , Lyon and Ziegler , Risse‐Buhl et al.…”

Section: Introductionmentioning

confidence: 99%

Pulse of dissolved organic matter alters reciprocal carbon subsidies between autotrophs and bacteria in stream food webs

Demars

Friberg

Thornton

2020

Ecological Monographs

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Citation: Demars, B. O. L., N. Friberg, and B. Thornton. 2020. Pulse of dissolved organic matter alters reciprocal carbon subsidies between autotrophs and bacteria in stream food webs. Ecological Monographs 90(1):Abstract. Soils are currently leaching out dissolved organic matter (DOM) at an increasing pace due to climate and land use change or recovery from acidification. The implications for stream biogeochemistry and food webs remain largely unknown, notably the metabolic balance (biotic CO 2 emissions) and carbon cycling between autotrophs and bacteria. We increased by 12% the flux of DOM in a stream for three weeks to mimic a pulse of natural DOM supply from soils rich in organic matter. We were able to track its fate into the food web through the use of a before and after control impact experimental design and the addition of DOM with a distinctive d 13 C signature. We used whole-stream metabolism to quantify carbon fluxes. Both photosynthesis and heterotrophic respiration increased rapidly following C addition, but this was short lived, likely due to nutrient limitations. Carbon exchange between autotrophs and bacteria in the control stream accounted for about 49% of bacterial production and 37% of net primary production, under stable flow conditions. Net primary production relied partly (19% in the control) on natural allochthonous dissolved organic carbon via the CO 2 produced by bacterial respiration, intermingling the green and brown webs. The preferential uptake of labile carbon by bacteria and excess bacterial CO 2 relative to nutrients (N, P) for autotrophs shifted the reciprocal carbon exchange between bacteria and autotrophs to a predominantly one-way carbon flow from bacteria to autotrophs, increasing the C:N:P molar ratios of autotrophs, the latter likely to become less palatable to consumers. The bacterial response to sucrose addition shifted the metabolic balance toward heterotrophy increasing biotic CO 2 emissions (+125%), shortened the average distance travelled by a molecule of organic matter (À40%), and thus provided less organic matter of lower quality for downstream ecosystems. Even a small increase in labile dissolved organic matter supply due to climate and land use change could significantly alter in-stream carbon cycling, with large effects on stream food web and biogeochemistry in small streams draining catchments with soils rich in organic carbon.

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Dissolved organic carbon uptake in streams: A review and assessment of reach‐scale measurements

Cited by 86 publications

References 69 publications

Animal‐mediated organic matter transformation: Aquatic insects as a source of microbially bioavailable organic nutrients and energy

Animal‐mediated organic matter transformation: Aquatic insects as a source of microbially bioavailable organic nutrients and energy

Behind the Scenes: Mechanisms Regulating Climatic Patterns of Dissolved Organic Carbon Uptake in Headwater Streams

Pulse of dissolved organic matter alters reciprocal carbon subsidies between autotrophs and bacteria in stream food webs

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