Modeling dissolved inorganic carbon considering submerged aquatic vegetation

Nakayama, Keisuke; Komai, Katsuaki; Tada, Kazufumi; Lin, Hao-Chi; Yajima, Hiroshi; Yano, Shinichiro; Hipsey, Matthew R.; Tsai, Jeng‐Wei

doi:10.1016/j.ecolmodel.2020.109188

“…These studies suggested that river intrusion and thermal stratification are key factors shaping the seasonal and interannual patterns of C fluxes during typhoon disturbances. River intrusion not only controlled the C fluxes, algal biomass, and nutrient loading, but also influenced the length of stratification and hydraulic retention times (Lin et al, 2021;Lin et al, 2022;Maranger et al, 2018;Nakayama et al, 2020;Olsson et al, 2022a;Olsson et al, 2022b;Zwart et al, 2017;Vachon and Del Giorgio, 2014). We hypothesized that allochthonous C loading and river inflow intrusion may affect the DIC and DOC distributions (Figure 1).…”

Section: Introductionmentioning

confidence: 95%

“…CC BY 4.0 License. sediment, and respiration contribute to DIC loading into lakes (Hope et al, 2004;Vachon et al, 2021); simultaneously, autotrophic organisms, such as planktons and submerged vegetation, capture DIC via photosynthesis (Amaral et al, 2022;Nakayama et al, 2020;Nakayama et al, 2022). Moreover, calcification and mineralization may consume dissolved oxygen within water, inducing uncertainty in pCO2 estimation (Hanson et al, 2015;Lin et al, 2022;Nakayama et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Conceptual models of dissolved carbon fluxes considering interannual typhoon responses under extreme climates in a two-layer stratified lake

Lin

¹

,

Nakayama²,

Tsai³

et al. 2022

Preprint

0

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Abstract. Extreme climates affect the seasonal and interannual patterns of carbon (C) distribution due to the regimes of river inflow and thermal stratification within lentic ecosystems. Typhoons rapidly load substantial amounts of terrestrial C into subtropical small lakes, renewing and mixing the water column. We developed conceptual dissolved C models and hypothesized that allochthonous C loading and river inflow intrusion may affect the dissolved inorganic C (DIC) and dissolved organic C (DOC) distributions in a small subtropical lake under these extreme climates. A two-layer conceptual C models was developed to explore how the DIC and DOC fluxes respond to typhoon disturbances on seasonal and interannual time scales in a small subtropical lake (i.e., Yuan‒Yang Lake) while simultaneously considering autochthonous processes such as algal photosynthesis, remineralization, and vertical transportation. Monthly field samplings were conducted to measure DIC, DOC, and chlorophyll a concentrations to compare the temporal patterns of fluxes between typhoon years (2015–2016) and non-typhoon years (2017–2018). The results demonstrated that net ecosystem production was 3.14 times higher in the typhoon years than in the non-typhoon years in Yuan‒Yang Lake. The results suggested that the load of allochthonous C was the most crucial factor affecting the temporal variation of C fluxes in the typhoon years; on the other hand, the transportation rate shaped the seasonal C in the non-typhoon years due to thermal stratification within this small subtropical lake.

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“…The executable binary (windows, Mac, Linux) of the three-dimensional hydrodynamic model, Fantom, used in this study, is available online (from http://www.comp.tmu.ac.jp/shintani/fantom.html). The model outputs are available from https://doi.org/10.5281/zenodo.3930609, "WRR2020: The model outputs for Nakayama et al (2020)".…”

Section: Data Availability Statementmentioning

confidence: 99%

“…Nellemann et al (2009) report that coastal blue carbon ecosystems accumulate approximately 55% of the total carbon dioxide captured from the Earth's atmosphere due to photosynthesis. While there is empirical evidence for blue carbon capture in seagrass systems, sequestration rates are highly variable (Lavery et al, 2013;Nakayama et al, 2020), and the conditions that can enhance or disrupt carbon capture and storage remains of topical interest. Similarly in inland waters, SAV has also been revealed to stabilize water quality in rivers (Weitzman et al, 2013), shallow lakes (Hilt et al, 2018), and potentially also within deep lakes (Sachse et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Integration of submerged aquatic vegetation motion within hydrodynamic models

Nakayama

¹

,

Shintani

²

,

Komai

³

et al. 2020

Preprint

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Aquatic models used for both freshwater and marine systems frequently need to account for submerged aquatic vegetation (SAV) due to its influence on flow and water quality. Despite its importance, parameterizations are generally adopted that simplify feedbacks from SAV, such as canopy properties (e.g., considering the deflected vegetation height) and the bulk friction coefficient. This study reports the development of a fine-scale non-hydrostatic model that demonstrates the two-way effects of SAV motion interaction with the flow. An object-oriented approach is applied to capture the multiphase phenomena, whereby a leaf-scale SAV model based on a discrete element method is combined with a flow dynamics model to resolve stresses from currents and waves. The model is verified through application to a laboratory-scale seagrass bed. A force balance analysis revealed that leaf elasticity and buoyancy are the most significant components influencing the horizontal and vertical momentum equations, respectively. The sensitivity of canopy-scale bulk friction coefficients to water depth, current speeds, and vegetation density of seagrass was explored. Deeper water was also shown to lead to a smaller decrease in vegetation height. The model approach can contribute to improving assessment of processes influencing water quality, sediment stabilization, carbon sequestration, and SAV restoration, thereby supporting an understanding of how waterways and coasts will respond to changes brought about by development and a changing climate. Plain Language Summary Aquatic system models that capture aquatic vegetation are increasingly important to help us understand processes controlling carbon budgets (e.g., "blue carbon") and for planning restoration efforts (e.g., Adams et al., 2016, https://doi.org/10.1002/lno.10319). Current models all rely on "static" approaches to account for vegetation via bulk parameterizations, though we know vegetation motion is important (e.g., Abdolahpour et al., 2018, https://doi.org/10.1002/lno.11008). Our study is the first to model the feedback between blade-scale vegetation motion and hydrodynamics to show it is crucial in shaping bottom mixing processes with implications for carbon and nutrient deposition.

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“…Nellemann et al (2009) report that coastal blue carbon ecosystems accumulate approximately 55% of the total carbon dioxide captured from the Earth's atmosphere due to photosynthesis. While there is empirical evidence for blue carbon capture in seagrass systems, sequestration rates are highly variable (Lavery et al, 2013; Nakayama et al, 2020), and the conditions that can enhance or disrupt carbon capture and storage remains of topical interest. Similarly in inland waters, SAV has also been revealed to stabilize water quality in rivers (Weitzman et al, 2013), shallow lakes (Hilt et al, 2018), and potentially also within deep lakes (Sachse et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Integration of Submerged Aquatic Vegetation Motion Within Hydrodynamic Models

Nakayama

¹

,

Shintani

²

,

Komai

³

et al. 2020

Water Resources Research

Self Cite

View full text Add to dashboard Cite

Aquatic models used for both freshwater and marine systems frequently need to account for submerged aquatic vegetation (SAV) due to its influence on flow and water quality. Despite its importance, parameterizations are generally adopted that simplify feedbacks from SAV, such as canopy properties (e.g., considering the deflected vegetation height) and the bulk friction coefficient. This study reports the development of a fine‐scale non‐hydrostatic model that demonstrates the two‐way effects of SAV motion interaction with the flow. An object‐oriented approach is applied to capture the multiphase phenomena, whereby a leaf‐scale SAV model based on a discrete element method is combined with a flow dynamics model to resolve stresses from currents and waves. The model is verified through application to a laboratory‐scale seagrass bed. A force balance analysis revealed that leaf elasticity and buoyancy are the most significant components influencing the horizontal and vertical momentum equations, respectively. The sensitivity of canopy‐scale bulk friction coefficients to water depth, current speeds, and vegetation density of seagrass was explored. Deeper water was also shown to lead to a smaller decrease in vegetation height. The model approach can contribute to improving assessment of processes influencing water quality, sediment stabilization, carbon sequestration, and SAV restoration, thereby supporting an understanding of how waterways and coasts will respond to changes brought about by development and a changing climate.

show abstract

Modeling dissolved inorganic carbon considering submerged aquatic vegetation

Cited by 20 publications

References 72 publications

Conceptual models of dissolved carbon fluxes considering interannual typhoon responses under extreme climates in a two-layer stratified lake

Conceptual models of dissolved carbon fluxes considering interannual typhoon responses under extreme climates in a two-layer stratified lake

Integration of submerged aquatic vegetation motion within hydrodynamic models

Integration of Submerged Aquatic Vegetation Motion Within Hydrodynamic Models

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