Inland water metabolic carbon processes and associated biological mechanisms that drive carbon source-sink instability

Abstract

<p>Due to their complexity, inland water carbon (C) cycling processes significantly impact the C source-sink stability status of terrestrial ecosystems over short-term, long-term, and geological timescales. Stable C source-sink processes primarily include terrestrial biospheric production, lithospheric organic carbon (OC) oxidization, rock weathering, and riverine C transport. Conversely, the effect of metabolic C processes on the C source-sink status of inland waterbodies is not stable. Therefore, inland water metabolic C processes may cause significant C sink underestimations, which relevant studies have largely ignored. A new way to account for this missing inland water C sink is an in-depth understanding of the metabolic C processes and associated driving effects of biological regulation mechanisms on the C source-sink status. This new approach can help to more accurately quantify the global ecosystem C budget. The purpose of this review is threefold: (i) to clarify metabolic C processes and associated biological regulation mechanisms of inland waterbodies; (ii) to systematically analyze C cycling processes and associated C source-sink statuses of inland waterbodies at different timescales; (iii) to reveal driving mechanisms of metabolic C processes on C source-sink stability in inland waterbodies. Doing so will help us better understand how to more accurately calibrate C source-sink functions globally while also garnering an in-depth understanding of the role that terrestrial ecosystems play in C neutralization under global climate change.</p>