Carbon dioxide evasion from a Boreal Catchment

Boreal headwaters potentially represent important conduits for the exchange of gaseous carbon between the terrestrial ecosystem and the atmosphere. Even if the loss is small in absolute terms compared to the uptake and release directly from forested terrestrial systems, it is a persistent term that is important when discussing the landscape carbon budget. Earlier studies in Sweden by Algesten et al. (2004) estimate the flux of gaseous carbon between boreal streams and the atmosphere to 0.5 g C/m2 &year. Similar studies in Brocky Burn, Scotland by Hope et al. (2001) show a flux up to 14 g C/m2 &year. The aim of this study is to determine the flux of carbon dioxide between streams in a typical Swedish boreal headwater catchment and the atmosphere. This was done by using the same method as in Brocky Burn. A comparison with other methods calculating the evasion was done in an attempt to get appropriate results. The study was performed within the headwater catchment of Krycklan in Västerbotten during 2003-2005. Totally around 570 water samples were taken during the period at different sites within the catchment and at different times of the year. The results from this study show that the loss of carbon from a boreal headwater catchment is somewhere between 2 and 13 g C/m2 &year. The wide range depends on the annual variation and what measurements are used in the calculations. Earlier Swedish studies seem to have underestimated the evasion flux of carbon dioxide from headwater streams. The study also shows that the evasion is to a great extent regulated by the spring flood

Practical Guide to Measuring Wetland Carbon Pools and Fluxes

Wetlands cover a small portion of the world, but have disproportionate infuence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fuxes. However, the underlying biogeochemical processes that afect wetland C pools and fuxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fuxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fuxes. We frst defne each of the major C pools and fuxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of fndings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions

Journal Staff

Half of the world's forest is in boreal and sub-boreal ecozones, containing large carbon stores and fluxes. Carbon lost from headwater streams in these forests is underestimated. We apply a simple stable carbon isotope idea for quantifying the CO2 loss from these small streams; it is based only on in-stream samples and integrates over a significant distance upstream. We demonstrate that conventional methods of determining CO2 loss from streams necessarily underestimate the CO2 loss with results from two catchments. Dissolved carbon export from headwater catchments is similar to CO2 loss from stream surfaces. Most of the CO2 originating in high CO2 groundwaters has been lost before typical in-stream sampling occurs. In the Harp Lake catchment in Canada, headwater streams account for 10% of catchment net CO2 uptake. In the Krycklan catchment in Sweden, this more than doubles the CO2 loss from the catchment. Thus, even when corrected for aquatic CO2 loss measured by conventional methods, boreal and sub-boreal forest carbon budgets currently overestimate carbon sequestration on the landscape

The patent management trichotomy: Patenting, publishing, and secrecy

Purpose Extant research and practice of patent management are often occupied with how to best utilize patenting as a source of competitive advantage. This paper instead suggests a patent management trichotomy where firms make strategic decisions between patenting, publishing, and secrecy. Approach The paper is conceptual in nature and draws on received IP-management literature to develop an analytical framework. Findings We suggest that the choice between patenting, publishing, and secrecy can be understood in terms of differences in the degree to which the firm can appropriate value from the invention and the degree to which it can operate freely. Originality/value Through an analysis along the dimensions of direct and indirect appropriation as well as static and dynamic freedom to operate, the article conceptualizes the choice between patenting, publishing, and secrecy in a way useful for management decisions as well as for academics

Following one's heart: cardiac rhythms gate central initiation of sympathetic reflexes

Central nervous processing of environmental stimuli requires integration of sensory information with ongoing autonomic control of cardiovascular function. Rhythmic feedback of cardiac and baroreceptor activity contributes dynamically to homeostatic autonomic control. We examined how the processing of brief somatosensory stimuli is altered across the cardiac cycle to evoke differential changes in bodily state. Using functional magnetic resonance imaging of brain and noninvasive beat-to-beat cardiovascular monitoring, we show that stimuli presented before and during early cardiac systole elicited differential changes in neural activity within amygdala, anterior insula and pons, and engendered different effects on blood pressure. Stimulation delivered during early systole inhibited blood pressure increases. Individual differences in heart rate variability predicted magnitude of differential cardiac timing responses within periaqueductal gray, amygdala and insula. Our findings highlight integration of somatosensory and phasic baroreceptor information at cortical, limbic and brainstem levels, with relevance to mechanisms underlying pain control, hypertension and anxiety

Remote Sensing Supported Sea Surface pCO(2) Estimation and Variable Analysis in the Baltic Sea

Marginal seas are a dynamic and still to large extent uncertain component of the global carbon cycle. The large temporal and spatial variations of sea-surface partial pressure of carbon dioxide (pCO(2)) in these areas are driven by multiple complex mechanisms. In this study, we analyzed the variable importance for the sea surface pCO(2) estimation in the Baltic Sea and derived monthly pCO(2) maps for the marginal sea during the period of July 2002-October 2011. We used variables obtained from remote sensing images and numerical models. The random forest algorithm was employed to construct regression models for pCO(2) estimation and produce the importance of different input variables. The study found that photosynthetically available radiation (PAR) was the most important variable for the pCO(2) estimation across the entire Baltic Sea, followed by sea surface temperature (SST), absorption of colored dissolved organic matter (a(CDOM)), and mixed layer depth (MLD). Interestingly, Chlorophyll-a concentration (Chl-a) and the diffuse attenuation coefficient for downwelling irradiance at 490 nm (Kd_490nm) showed relatively low importance for the pCO(2) estimation. This was mainly attributed to the high correlation of Chl-a and Kd_490nm to other pCO(2)-relevant variables (e.g., a(CDOM)), particularly in the summer months. In addition, the variables' importance for pCO(2) estimation varied between seasons and sub-basins. For example, the importance of a(CDOM) were large in the Gulf of Finland but marginal in other sub-basins. The model for pCO(2) estimate in the entire Baltic Sea explained 63% of the variation and had a root of mean squared error (RMSE) of 47.8 mu atm. The pCO(2) maps derived with this model displayed realistic seasonal variations and spatial features of sea surface pCO(2) in the Baltic Sea. The spatially and seasonally varying variables' importance for the pCO(2) estimation shed light on the heterogeneities in the biogeochemical and physical processes driving the carbon cycling in the Baltic Sea and can serve as an important basis for future pCO(2) estimation in marginal seas using remote sensing techniques. The pCO(2) maps derived in this study provided a robust benchmark for understanding the spatiotemporal patterns of CO2 air-sea exchange in the Baltic Sea

Carbon dioxide dynamics in an agricultural headwater stream driven by hydrology and primary production

Headwater streams are known to be hotspots for carbon dioxide (CO2) emissions to the atmosphere and are hence important components in landscape carbon balances. However, surprisingly little is known about stream CO2 dynamics and emissions in agricultural settings, a land use type that globally covers ca. 40% of the continental area. Here we present hourly measured in situ stream CO2 concentration data from a 11.3 km(2) temperate agricultural headwater catchment covering more than 1 year (in total 339 d excluding periods of ice and snow cover). The stream CO2 concentrations during the entire study period were generally high (median 3.44 mg C L-1, corresponding to partial pressures (pCO(2)) of 4778 mu atm) but were also highly variable (IQR = 3.26 mgC L-1). The CO2 concentration dynamics covered a variety of different timescales from seasonal to hourly, with an interplay of hydrological and biological controls. The hydrological control was strong (although with both positive and negative influences dependent on season), and CO2 concentrations changed rapidly in response to rainfall and snowmelt events. However, during growing-season base flow and receding flow conditions, aquatic primary production seemed to control the stream CO2 dynamics, resulting in elevated diel patterns. During the dry summer period, rapid rewetting following precipitation events generated high CO2 pulses exceeding the overall median level of stream CO2 (up to 3 times higher) observed during the whole study period. This finding highlights the importance of stream intermittency and its effect on stream CO2 dynamics. Given the observed high levels of CO2 and its temporally variable nature, agricultural streams clearly need more attention in order to understand and incorporate these considerable dynamics in large-scale extrapolations

Autumn destabilization of deep porewater CO2 store in a northern peatland driven by turbulent diffusion

The CO2 stored in deep peat porewater is viewed as a fixed component of peatland C cycling. Here, the authors reveal a hitherto unknown hydro-physical process that results in sudden losses from this CO2 store every autumn.The deep porewater of northern peatlands stores large amounts of carbon dioxide (CO2). This store is viewed as a stable feature in the peatland CO2 cycle. Here, we report large and rapid fluctuations in deep porewater CO2 concentration recurring every autumn over four consecutive years in a boreal peatland. Estimates of the vertical diffusion of heat indicate that CO2 diffusion occurs at the turbulent rather than molecular rate. The weakening of porewater thermal stratification in autumn likely increases turbulent diffusion, thus fostering a rapid diffusion of deeper porewater CO2 towards the surface where net losses occur. This phenomenon periodically decreases the peat porewater CO2 store by between 29 and 90 g C m(-2) throughout autumn, which is comparable to the peatland's annual C-sink. Our results establish the need to consider the role of turbulent diffusion in regularly destabilizing the CO2 store in peat porewater