Catchment productivity controls CO2 emissions from lakes

Maberly, Stephen C.; Barker, Philip A.; Stott, Alistair W.; Ville, M.M. De

doi:10.1038/nclimate1748

Cited by 182 publications

(158 citation statements)

References 29 publications

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“…For example, recent inter-regional assessments have highlighted the importance of terrestrial inorganic C inputs in shaping aquatic CO 2 dynamics 6,33,39 . Similarly, studies that have targeted specific components of the aquatic network, such as low DOC lakes 40 or headwater streams 41 , have also highlighted the importance of soil CO 2 inputs. There is no actual contradiction between these various studies and the results we present here: the direct influence of terrestrial DOC is superimposed onto a background of CO 2 dynamics driven by external inputs of CO 2 .…”

Section: Discussionmentioning

confidence: 99%

Increases in terrestrially derived carbon stimulate organic carbon processing and CO2 emissions in boreal aquatic ecosystems

et al. 2013

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Section: Discussionmentioning

confidence: 99%

Increases in terrestrially derived carbon stimulate organic carbon processing and CO2 emissions in boreal aquatic ecosystems

et al. 2013

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“…Although the groundwater DIC represented a larger proportion of the loaded C in Schulzensee (Fig. 3), similar groundwater DIC concentrations and net loading rates (Table 2) between these lakes suggest that the significant difference observed in pelagic DIC concentrations (and surface emissions) is most likely due to within-lake metabolic processes, rather than differences in hydrology (Stets et al 2009) or catchment productivity (Maberly et al 2012). …”

Section: Carbon Balancesmentioning

confidence: 99%

A regime shift from macrophyte to phytoplankton dominance enhances carbon burial in a shallow, eutrophic lake

et al. 2013

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Abstract. Ecological regime shifts and carbon cycling in aquatic systems have both been subject to increasing attention in recent years, yet the direct connection between these topics has remained poorly understood. A four-fold increase in sedimentation rates was observed within the past 50 years in a shallow eutrophic lake with no surface in-or outflows. This change coincided with an ecological regime shift involving the complete loss of submerged macrophytes, leading to a more turbid, phytoplanktondominated state. To determine whether the increase in carbon (C) burial resulted from a comprehensive transformation of C cycling pathways in parallel to this regime shift, we compared the annual C balances (mass balance and ecosystem budget) of this turbid lake to a similar nearby lake with submerged macrophytes, a higher transparency, and similar nutrient concentrations. C balances indicated that roughly 80% of the C input was permanently buried in the turbid lake sediments, compared to 40% in the clearer macrophyte-dominated lake. This was due to a higher measured C burial efficiency in the turbid lake, which could be explained by lower benthic C mineralization rates. These lower mineralization rates were associated with a decrease in benthic oxygen availability coinciding with the loss of submerged macrophytes. In contrast to previous assumptions that a regime shift to phytoplankton dominance decreases lake heterotrophy by boosting whole-lake primary production, our results suggest that an equivalent net metabolic shift may also result from lower C mineralization rates in a shallow, turbid lake. The widespread occurrence of such shifts may thus fundamentally alter the role of shallow lakes in the global C cycle, away from channeling terrestrial C to the atmosphere and towards burying an increasing amount of C.

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“…Concentrations of CO 2 in lakes frequently exceed air-equilibrium as a result of input from the catchment of CO 2 or terrestrially fixed organic carbon that is oxidised to CO 2 (Cole et al 2007;Maberly et al 2013). However, in productive systems the rate of carbon-fixation in a unit volume of water can greatly exceed rates of carbon supply from the atmosphere, or other sources, leading to depletion of CO 2 virtually to zero (Maberly 1996) limiting productivity (Ibelings and Maberly 1998;Jansson et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Biochemical and biophysical CO2 concentrating mechanisms in two species of freshwater macrophyte within the genus Ottelia (Hydrocharitaceae)

et al. 2013

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Two freshwater macrophytes, Ottelia alismoides and Ottelia acuminata, were grown at low (mean 5 µmol L -1 ) and high (mean 400 µmol L -1 ) CO 2 concentrations under natural conditions. The ratio of PEPC to RuBisCO activity was 1.8 in O. acuminata in both treatments. In O. alismoides, this ratio was 2.8 and 5.9 when grown at high and low CO 2 , respectively, as a result of a 2-fold increase in PEPC activity. The activity of PPDK was similar to, and changed with, PEPC (1.9-fold change). The activity of the decarboxylating NADP-malic enzyme (ME) was very low in both species while NAD-ME activity was high and increased with PEPC activity in O. alismoides. These results suggest that O.alismoides might perform a type of C 4 metabolism with NAD-ME decarboxylation, despite lacking Kranz anatomy. The C 4 -activity was still present at high CO 2 suggesting that it could be constitutive.O. alismoides at low CO 2 showed diel acidity variation of up to 34 μequiv g -1 FW indicating that it may also operate a form of Crassulacean Acid Metabolism (CAM). pH-drift experiments showed that both species were able to use bicarbonate. In O. acuminata, the kinetics of carbon uptake were altered by CO 2 growth conditions, unlike in O. alismoides. Thus the two species appear to regulate their carbon concentrating mechanisms differently in response to changing CO 2 . O. alismoides is potentially using three different concentrating mechanisms. The Hydrocharitaceae have many species with evidence for C 4 , CAM, or some other metabolism involving organic acids, and are worthy of further study.3

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Catchment productivity controls CO2 emissions from lakes

Abstract: Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner.

Cited by 182 publications

References 29 publications

Increases in terrestrially derived carbon stimulate organic carbon processing and CO2 emissions in boreal aquatic ecosystems

Increases in terrestrially derived carbon stimulate organic carbon processing and CO2 emissions in boreal aquatic ecosystems

A regime shift from macrophyte to phytoplankton dominance enhances carbon burial in a shallow, eutrophic lake

Biochemical and biophysical CO2 concentrating mechanisms in two species of freshwater macrophyte within the genus Ottelia (Hydrocharitaceae)

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