Aquatic Carbon Fluxes
Summary
Integrated ecosystem carbon budgets incorporating both terrestrial and aquatic pathways are rare. This is largely due to the disciplinary nature of science, where methodological constraints tend to enhance the focus on specific components of the carbon balance (Falkowski and others 2000). At the catchment scale, there is currently little consensus or predictable patterns on the relative contribution of aquatic pathways in ecosystem carbon budgets. Consequently, the importance of both aquatic and terrestrial carbon processes and pools at the catchment scale remains underrepresented in discipline-focused ecosystem studies.
The importance of fully integrated carbon budgets has now been demonstrated by numerous studies. Correct accounting of both aquatic and terrestrial carbon fluxes has shifted the source-sink status of ecosystems (Genereux and others 2013; Chu and others 2015; Lundin and others 2016). Local-scale studies (ecosystem specific at the catchment level) on ecosystem carbon budgets are useful for identifying specific carbon fluxes that contribute to the overall budget. For example, studies measuring both terrestrial and aquatic carbon fluxes were first reported for a lowland temperate peatland catchment (Billett and others 2004) and temperate forest in the early 2000s (Shibata and others 2005). There are now sufficient studies on terrestrial–aquatic carbon budgets at the catchment scale to allow for analyses of broad-scale patterns.[1]
Amazon Rainforest
The land–ocean aquatic continuum (LOAC) is now well established as an important component of the global carbon (C) cycle (Ciais et al., 2013). Atmospheric C fixed in terrestrial ecosystems and wetlands can be lost through respiration, and stored in biomass and soil, but can also be transferred laterally to the LOAC as dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved CO2. Along the LOAC this C can in turn undergo biogeochemical transformations, be lost back to the atmosphere via CO2 evasion, transferred further downstream to estuaries and the coast or undergo sedimentation in wetlands (incl. lakes and reservoirs). It has been demonstrated at the catchment (Cole & Caraco, 1998) to global scale (Battin et al., 2009; Ciais et al., in review; Regnier et al., 2013), that these fluxes are important and should not be neglected in land C budgets.[2]
Lack of Research
... At present, aquatic carbon fluxes are inconsistently evaluated in the context of landscape carbon budgets. This is primarily linked to the terrestrial and aquatic carbon components that are measured and/or included, and the scale at which these fluxes are represented. Butman and others (2016) provide the most complete quantitative assessment of the contribution of aquatic pathways to terrestrial carbon budgets on a regional scale, yet highlight how our ability to model terrestrial–aquatic exchanges is limited by direct measurements. To better understand the contribution of aquatic pathways to land-based carbon budgets, attention needs to be directed to smaller-scale, ecosystem-specific studies that may provide a more detailed view of aquatic carbon fluxes and drivers...[3]
Related
Sources
- ↑ Webb, J.R., Santos, I.R., Maher, D.T. et al. The Importance of Aquatic Carbon Fluxes in Net Ecosystem Carbon Budgets: A Catchment-Scale Review. Ecosystems 22, 508–527 (2019). https://doi.org/10.1007/s10021-018-0284-7
- ↑ https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.14620?casa_token=nIxAOGMrvrgAAAAA%3AdcK_qdoV0-FghJxpDDfnhcDlONRKe9uyYN6H2c35Vj9kZy-l9vjNSpjAgKYYTji1LKXWwXRkOvUCtP_g
- ↑ Webb, J.R., Santos, I.R., Maher, D.T. et al. The Importance of Aquatic Carbon Fluxes in Net Ecosystem Carbon Budgets: A Catchment-Scale Review. Ecosystems 22, 508–527 (2019). https://doi.org/10.1007/s10021-018-0284-7