Terrestrial loads of dissolved organic matter drive inter-annual carbon flux in subtropical lakes during times of drought

Chiu, Chih‐Yu; Jones, John R.; Rusak, James A.; Lin, Hao-Chi; Nakayama, Keisuke; Kratz, Timothy K.; Liu, Wen‐Cheng; Tang, Sen-Lin; Tsai, Jeng‐Wei

doi:10.1016/j.scitotenv.2020.137052

Cited by 23 publications

(41 citation statements)

References 92 publications

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“…This process usually enriches the remaining DIC in 13 C. Additionally, increased rainfall may also have flushed 13 C-depleted DIC and POC from the surrounding catchment 17 . The observed more positive δ 13 C DIC values near the water surface likely result from equilibration with atmospheric CO 2 and photosynthesis that both enrich the remaining DIC in 13 C.…”

Section: Discussionmentioning

confidence: 98%

“…However, this approach only offers a subjective indicator for dominance of external or internal POC sources. Combined investigation of δ 13 C POC and δ 13 C DIC values seem more promising to help separating POC sources, because this technique also maps transformations of carbon. Therefore, the application of a carbon stable isotope fractionation model should be able to provide distinct information on POC sources.…”

Section: Discussionmentioning

confidence: 99%

“…where R is the ratio of the heavy to the light carbon isotope (i.e. 13 C/ 12 C) 62 . All isotope data were corrected for instrumental drift and linearity.…”

Section: Methodsmentioning

confidence: 99%

“…Such processes include carbon uptake and release of carbon within the water column that may also be controlled by seasonal changes of temperature, weather patterns or light availability. These may in turn have important influences on carbon fluxes inside open water bodies such as for instance sedimentation, or gross primary production, ecosystem respiration and external carbon inputs 13 . For the latter, reservoir catchments may offer large but unknown contributions that may exceed internal (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Dominance of in situ produced particulate organic carbon in a subtropical reservoir inferred from carbon stable isotopes

Bueno

Frascareli

Gontijo

et al. 2020

Sci Rep

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Sources of particulate organic carbon (poc) play important roles in aqueous carbon cycling because internal production can provide labile material that can easily be turned into CO 2. On the other hand, more recalcitrant external POC inputs can cause increased loads to sedimentary organic matter that may ultimately cause cH 4 release. In order to differentiate sources, stable isotopes offer a useful tool. We present a study on the Itupararanga Reservoir (Brazil) where origins of POC were explored by comparing its isotope ratios (δ 13 c poc) to those of dissolved inorganic carbon (δ 13 c Dic). The δ 13 c poc averaged around − 25.1‰ in near-surface waters, which indicates higher primary production inferred from a fractionation model that takes into account carbon transfer with a combined evaluation of δ 13 c POC, δ 13 c Dic and aqueous co 2. However, δ 13 c poc values for water depths from 3 to 15 m decreased to − 35.6‰ and indicated different carbon sources. Accordingly, the δ 13 c Dic values of the reservoir averaged around + 0.6‰ in the top 3 m of the water column. This indicates CO 2 degassing and photosynthesis. Below this depth, DIC isotope values of as low as − 10.1‰ showed stronger influences of respiration. A fractionation model with both isotope parameters revealed that 24% of the POC in the reservoir originated from detritus outside the reservoir and 76% of it was produced internally by aqueous co 2 fixation. Reservoirs and their tributaries are active components of landscapes. They receive, transport, process and store inorganic and organic carbon 1. Although lakes and reservoirs cover only 2.2% of the global continental area, they may play so far poorly accounted roles in cycling continental carbon 2-4. In addition, regional investigations of carbon budgets become increasingly important for managing water resources because they define ecosystem functions and services 5-8. Spatiotemporal changes of physicochemical and biological parameters in subtropical reservoirs, can increase our knowledge of carbon turnover in water bodies. For instance, excessive precipitation, can increase terrestrial nutrients, contaminants, soil leaching and additions of untreated sewage input 9. Rainfall events can also cause near-surface turbulences in lakes that has been shown to enhance gas exchange by increasing transfer velocities of CO 2 10,11. Precipitation can also lead to increased input from external sources (i.e. allochthonous matter for instance from plant debris or soils) that may become trapped in lakes and reservoirs. This can, in turn, change biogeochemical dynamics of the water column 12. Such processes include carbon uptake and release of carbon within the water column that may also be controlled by seasonal changes of temperature, weather patterns or light availability. These may in turn have important influences on carbon fluxes inside open water bodies such as for instance sedimentation, or gross primary production, ecosystem respiration and external carbon inputs 13. For the latter, reservoir catchments ma...

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

“…where R is the ratio of the heavy to the light carbon isotope (i.e. 13 C/ 12 C) 62 . All isotope data were corrected for instrumental drift and linearity.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dominance of in situ produced particulate organic carbon in a subtropical reservoir inferred from carbon stable isotopes

Bueno

Frascareli

Gontijo

et al. 2020

Sci Rep

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“…In the present study, as shown in Table 1, Rdaytime, Rnight, and R24h were estimated using sensor data and certain periods of the instantaneous NCP data and were integrated either from sunrise to sunset or only over the production period (e.g., only when the instantaneous NCP was positive). Means of instantaneous NCP over certain time periods were used as in previous studies, including Staehr et al (2010 a , b ), Laas et al (2012), Idrizag et al (2016), Richardson et al (2017), and Chiu et al (2020). More precisely, Rdaytime was estimated either with the mean of the instantaneous NCP during a 1‐h period centered on the maximum of the instantaneous Negative NCP (hereafter referred to as the “Max” method) or with the mean of the instantaneous NCP during a 1‐h period following sunset, as in Mostajir et al (2013) (hereafter referred to as the “Most” method).…”

Section: Materials and Proceduresmentioning

confidence: 99%

A new method to estimate planktonic oxygen metabolism using high‐frequency sensor measurements in mesocosm experiments and considering daytime and nighttime respirations

Soulié

Mas²,

Parin³

et al. 2021

Limnology & Ocean Methods

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Understanding how aquatic ecosystems respond to perturbations has emerged as a crucial way to predict the future of these ecosystems and to assess their capacity to produce oxygen and store atmospheric carbon. In this context, in situ mesocosm experiments are a useful approach for simulating disturbances and observing changes in planktonic communities over time and under controlled conditions. Within mesocosm experiments, the estimation of fundamental parameters such as gross primary production (GPP), net community production (NCP), and respiration (R) allows the evaluation of planktonic metabolic responses to a perturbation. The continuous estimation of these metabolic parameters in real time and at high frequency is made possible by employing noninvasive automated sensors in the water column. However, some uncertainties and methodological questions about the estimation of daytime respiration remain to be addressed for this method, and notably to address the fact that respiration could be significantly higher during the day than during the night. In this study, data from two in situ mesocosm experiments performed in fall and spring in a coastal Mediterranean area were used to develop a new method of estimating daytime respiration, and in turn daily GPP, R, and NCP, by considering the maximum instantaneous R, and that takes into account the variability of the coupling between day-night and dissolved oxygen cycles. This new method was compared with the Winkler incubation technique and with another existing method. Results showed that using this existing method, daytime R was significantly underestimated relative to estimates obtained with the newly proposed method.

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Influence of thermal stratification on seasonal net ecosystem production and dissolved inorganic carbon in a shallow subtropical lake

Lin

Chiu

Tsai³

et al. 2020

Preprint

Self Cite

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Plain Language Summary Vertical distribution of dissolved inorganic C (DIC) is one of the most important factors for understanding C emission from lakes. Thermal stratification is expected to be the critical physical process controlling the vertical distribution of DIC. To clarify the relationship between DIC and thermal stratification, we investigated vertical profiles of DIC and the strength of stratification in a subtropical shallow lake (Yuan-Yang Lake [YYL]) using field observations from 2004 to 2017. Our study is the first to apply a three-dimensional hydrological model to clarify the mechanism controlling the vertical profile of DIC as part of an estimate of net ecosystem production in a lake. LIN ET AL.

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Terrestrial loads of dissolved organic matter drive inter-annual carbon flux in subtropical lakes during times of drought

Cited by 23 publications

References 92 publications

Dominance of in situ produced particulate organic carbon in a subtropical reservoir inferred from carbon stable isotopes

Dominance of in situ produced particulate organic carbon in a subtropical reservoir inferred from carbon stable isotopes

A new method to estimate planktonic oxygen metabolism using high‐frequency sensor measurements in mesocosm experiments and considering daytime and nighttime respirations

Influence of thermal stratification on seasonal net ecosystem production and dissolved inorganic carbon in a shallow subtropical lake

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