scholarly journals Moderate increases in channel discharge are positively related to ecosystem respiration in forested Ozark streams

2021 ◽  
Author(s):  
Allyn K. Dodd ◽  
Daniel D. Magoulick ◽  
Michelle A. Evans-White
Keyword(s):  
Primary Production ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Carbon Sources ◽  
Flow Regimes ◽  
Water Source ◽  
Stream Metabolism ◽  
Global Trends ◽  
Ecosystem Level ◽  
And Function

ABSTRACTThe natural flow regime is considered the “master variable” in lotic systems, controlling structure and function at organismal, population, community, and ecosystem levels. We sought to estimate forested headwater stream metabolism across two dominant flow regimes (Runoff and Groundwater) in northern Arkansas and evaluate potential differences in, and drivers of, gross primary production, ecosystem respiration, and net ecosystem metabolism. Flow regimes differed in intermittency, substrate heterogeneity, hyporheic connectivity, and dominant water source (subsurface runoff vs. groundwater), which we expected to result in differences in primary production and respiration. Average daily gross primary production (GPP) and ecosystem respiration (ER) estimated from field data collected from May 2015-June 2016 tended to be greater in Groundwater streams. Respiration was positively related to discharge (R2= 0.98 p< 0.0001) and net metabolism became more heterotrophic with increasing average annual discharge across sites (R2= 0.94, p= 0.0008). Characterizing ecosystem-level responses to differences in flow can reveal mechanisms governing stream metabolism and, in turn, provide information regarding trophic state and energy inputs as efforts continue to determine global trends in aquatic carbon sources and fates.

Pharmaceuticals and personal care products alter growth and function in lentic biofilms

2015 ◽  
Vol 12 (3) ◽  
pp. 301 ◽  
Author(s):  
Lawton Shaw ◽  
Chuyen Phung ◽  
Michael Grace
Keyword(s):  
Primary Production ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Personal Care Products ◽  
Algal Growth ◽  
Biologically Active ◽  
Community Respiration ◽  
Personal Care ◽  
Ecological Processes ◽  
And Function

Environmental context Pharmaceuticals and personal care products are routinely found in waters discharged from treatment plants and in surrounding aquatic ecosystems. Despite the widespread occurrence of these biologically active agents, there is limited understanding of their potential effects on key ecosystem processes such as primary production, ecosystem respiration and algal growth. This paper examines the effects of five common pharmaceuticals on the rates of these fundamental processes. Abstract Pharmaceutical diffusing substrates were used to study in situ responses of aquatic biofilms in an urbanised lentic ecosystem to five pharmaceutical and personal care products (PPCPs; caffeine, cimetidine, ciprofloxacin, diphenhydramine and metformin). The pharmaceutical diffusing substrates consisted of porous biofilm substrates placed atop a mass of agar amended with 2.5mM of the PPCP compound of interest. Over 21 days, biofilms growing on the substrata were exposed to slow diffusion of the PPCP through the agar and porous substrate. Algal biomass was suppressed by exposure to diphenhydramine (–81%) and ciprofloxacin (–50%). Gross primary production was completely suppressed by diphenhydramine exposure but stimulated by caffeine (+39%) and cimetidine (+46%). For heterotroph biofilms, community respiration was suppressed by exposure to diphenhydramine (–24%). To characterise PPCP exposure, rates of diffusion from the pharmaceutical diffusing substrates were measured at 10, 20 and 30°C. Diffusion was Fickian for all compounds and all temperatures. Diffusion coefficients, D, were in the range 1.5×10–10 to 1.1×10–9m2s–1. From diffusion data, average release rates over 21 days were typically 30–50ngmin–1cm–2 at 20°C. The results show that PPCPs can dramatically affect rates of key ecological processes, and the relationship between release rate and ambient concentration of PPCPs is discussed.

scholarly journals High Rates of Ecosytem Metabolism in Five Western Rivers

2011 ◽  
Vol 33 ◽  
pp. 115-118
Author(s):  
Robert Hall ◽  
Jennifer Tank ◽  
Michelle Baker ◽  
Emma Rosi-Marshall ◽  
Michael Grace ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Carbon Cycling ◽  
Carbon Balance ◽  
Carbon Fixation ◽  
Higher Plants ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Total Rate ◽  
Global Carbon

Primary production and respiration are core functions of river ecosystems that in part determine the carbon balance. Gross primary production (GPP) is the total rate of carbon fixation by autotrophs such as algae and higher plants and is equivalent to photosynthesis. Ecosystem respiration (ER) measures rate at which organic carbon is mineralized to CO2 by all organisms in an ecosystem. Together these fluxes can indicate the base of the food web to support animal production (Marcarelli et al. 2011), can predict the cycling of other elements (Hall and Tank 2003), and can link ecosystems to global carbon cycling (Cole et al. 2007).

Mismatch between the optimal ages for ecosystem productivity and net CO2 sequestration in Norway spruce forests

2021 ◽  
Author(s):  
Junbin Zhao ◽  
Holger Lange ◽  
Helge Meissner
Keyword(s):  
Climate Change ◽  
Primary Production ◽  
Norway Spruce ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Economic Benefits ◽  
Sink Strength ◽  
Climate Change Scenarios ◽  
Ecosystem Productivity ◽  
Spruce Forests

&lt;p&gt;Forests have climate change mitigation potential since they sequester carbon. However, their carbon sink strength might depend on management. As a result of the balance between CO&lt;sub&gt;2&lt;/sub&gt; uptake and emission, forest net ecosystem exchange (NEE) reaches optimal values (maximum sink strength) at young stand ages, followed by a gradual NEE decline over many years. Traditionally, this peak of NEE is believed to be concurrent with the peak of primary production (e.g., gross primary production, GPP); however, in theory, this concurrence may potentially vary depending on tree species, site conditions and the patterns of ecosystem respiration (R&lt;sub&gt;eco&lt;/sub&gt;). In this study, we used eddy-covariance (EC)-based CO&lt;sub&gt;2&lt;/sub&gt; flux measurements from 8 forest sites that are dominated by Norway spruce (Picea abies L.) and built machine learning models to find the optimal age of ecosystem productivity and that of CO&lt;sub&gt;2&lt;/sub&gt; sequestration. We found that the net CO&lt;sub&gt;2&lt;/sub&gt; uptake of Norway spruce forests peaked at ages of 30-40 yrs. Surprisingly, this NEE peak did not overlap with the peak of GPP, which appeared later at ages of 60-90 yrs. The mismatch between NEE and GPP was a result of the R&lt;sub&gt;eco&lt;/sub&gt; increase that lagged behind the GPP increase associated with the tree growth at early age. Moreover, we also found that newly planted Norway spruce stands had a high probability (up to 90%) of being a C source in the first year, while, at an age as young as 5 yrs, they were likely to be a sink already. Further, using common climate change scenarios, our model results suggest that net CO&lt;sub&gt;2&lt;/sub&gt; uptake of Norway spruce forests will increase under the future climate with young stands in the high latitude areas being more beneficial. Overall, the results suggest that forest management practices should consider NEE and forest productivity separately and harvests should be performed only after the optimal ages of both the CO&lt;sub&gt;2&lt;/sub&gt; sequestration and productivity to gain full ecological and economic benefits.&lt;/p&gt;

Energy and nutrients

2019 ◽  
pp. 161-176
Author(s):  
Richard T. Corlett
Keyword(s):  
Primary Production ◽  
Forest Ecology ◽  
Net Primary Production ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Nitrogen And Phosphorus ◽  
New Information ◽  
Tropical Forest Ecology ◽  
Toxic Concentrations

This chapter deals with the ecology of Tropical East Asia from the perspective of water, energy, and matter flows through ecosystems, particularly forests. Data from the network of eddy flux covariance towers is revealing general patterns in gross primary production, ecosystem respiration, and net ecosystem production, and exchange. There is also new information on the patterns of net primary production and biomass within the region. In contrast, our understanding of the role of soil nutrients in tropical forest ecology still relies mostly on work done in the Neotropics, with just enough data from Asia to suggest that the major patterns may be pantropical. Nitrogen and phosphorus have received most attention regionally, followed by calcium, potassium, and magnesium, and there has been very little study of the role of micronutrients and potentially toxic concentrations of aluminium, manganese, and hydrogen ions. Animal nutrition has also been neglected.

scholarly journals Carbon Balance in Salt Marsh and Mangrove Ecosystems: A Global Synthesis

2020 ◽  
Vol 8 (10) ◽  
pp. 767 ◽  
Author(s):  
Daniel M. Alongi
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Salt Marshes ◽  
Dissolved Inorganic Carbon ◽  
Net Primary Production ◽  
Ecosystem Respiration ◽  
Soil Depth ◽  
Gross Primary Production ◽  
Coastal Ocean ◽  
Microbial Decomposition

Mangroves and salt marshes are among the most productive ecosystems in the global coastal ocean. Mangroves store more carbon (739 Mg CORG ha−1) than salt marshes (334 Mg CORG ha−1), but the latter sequester proportionally more (24%) net primary production (NPP) than mangroves (12%). Mangroves exhibit greater rates of gross primary production (GPP), aboveground net primary production (AGNPP) and plant respiration (RC), with higher PGPP/RC ratios, but salt marshes exhibit greater rates of below-ground NPP (BGNPP). Mangroves have greater rates of subsurface DIC production and, unlike salt marshes, exhibit active microbial decomposition to a soil depth of 1 m. Salt marshes release more CH4 from soil and creek waters and export more dissolved CH4, but mangroves release more CO2 from tidal waters and export greater amounts of particulate organic carbon (POC), dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC), to adjacent waters. Both ecosystems contribute only a small proportion of GPP, RE (ecosystem respiration) and NEP (net ecosystem production) to the global coastal ocean due to their small global area, but contribute 72% of air–sea CO2 exchange of the world’s wetlands and estuaries and contribute 34% of DIC export and 17% of DOC + POC export to the world’s coastal ocean. Thus, both wetland ecosystems contribute disproportionately to carbon flow of the global coastal ocean.

scholarly journals Observed and modelled ecosystem respiration and gross primary production of a grassland in southwestern France

2010 ◽  
Vol 7 (1) ◽  
pp. 429-462 ◽  
Author(s):  
C. Albergel ◽  
J.-C. Calvet ◽  
A.-L. Gibelin ◽  
S. Lafont ◽  
J.-L. Roujean ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Primary Production ◽  
Root Zone ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Net Ecosystem Exchange ◽  
Co2 Flux ◽  
Single Equation ◽  
Complex Model ◽  
Area Index

Abstract. In this work, a simple representation of the soil moisture effect on the ecosystem respiration is implemented into the A-gs version of the Interactions between Soil, Biosphere, and Atmosphere (ISBA) model. It results in an improvement of the modelled CO2 flux over a grassland, in southwestern France. The former temperature-only dependent respiration formulation used in ISBA-A-gs is not able to model the limitation of the respiration under dry conditions. In addition to soil moisture and soil temperature, the only parameter required in this formulation is the ecosystem respiration parameter Re25. It can be estimated by the mean of eddy covariance measurements of turbulent nighttime CO2 flux (i.e. ecosystem respiration). The resulting correlation between observed and modelled net ecosystem exchange is r2=0.63 with a bias of −2.18 μmol m−2 s−1. It is shown that when CO2 observations are not available, it is possible to use a more complex model, able to represent the heterotrophic respiration and all the components of the autotrophic respiration, to estimate Re25 with similar results. The modelled ecosystem respiration estimates are provided by the Carbon Cycle (CC) version of ISBA (ISBA-CC). ISBA-CC is a version of ISBA able to simulate all the respiration components whereas ISBA-A-gs uses a single equation for ecosystem respiration. ISBA-A-gs is easier to handle and more convenient than ISBA-CC for practical use in atmospheric or hydrological models. Surface water and energy flux observations as well as gross primary production (GPP) estimates are compared with model outputs. The dependence of GPP to air temperature is investigated. The observed GPP is less sensitive to temperature than the modelled GPP. Finally, the simulations of the ISBA-A-gs model are analysed over a seven year period (2001–2007). Modelled soil moisture and leaf area index (LAI) are confronted with the observed root-zone soil moisture content (m3 m−3), and with LAI estimates derived from surface reflectance measurements.

scholarly journals Eddy covariance carbon flux in a scrub in the Mexican highland

2020 ◽  
Author(s):  
Aurelio Guevara-Escobar ◽  
Enrique González-Sosa ◽  
Mónica Cervantes-Jiménez ◽  
Humberto Suzán-Azpiri ◽  
Mónica Elisa Queijeiro-Bolaños ◽  
...  
Keyword(s):  
Primary Production ◽  
Eddy Covariance ◽  
Vegetation Index ◽  
Carbon Sink ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Net Ecosystem Exchange ◽  
R Package ◽  
Dark Cycle ◽  
Remote Sensors

Abstract. Vegetation fixes C in its biomass through photosynthesis or might release it into the atmosphere through respiration. Measurements of these fluxes would help us understand ecosystem functioning. The eddy covariance technique (EC) is widely used to measure the net ecosystem exchange of C (NEE) which is the balance between gross primary production (GPP) and ecosystem respiration (Reco). Orbital satellites such as MODIS can also provide estimates of GPP. In this study, we measured NEE with the EC in a scrub at Bernal in Mexico, and then partitioned into gross primary production (GPP-EC) and Reco using the recent R package Reddyproc. Measurements of GPP-EC were related to the estimates from the MODIS satellite provided in product MOD17A2H, which contains data of the gross primary productivity (GPP-MODIS). The Bernal site was a carbon sink despite it was an overgrazed site, the average NEE during fifteen months of 2017 and 2018 was −0.78 g C m−2 d−1 and the flux was negative in all measured months. The GPP-MODIS underestimated the ground data when representing the relation with a Theil-Sen regression: GPP-EC = 1.866 + 1.861 GPP-MODIS; an ordinary less squares regression had similar coefficients and the R2 was 0.6. Although cacti (CAM), legume shrubs (C3) and herbs (C3) had a similar vegetation index, the nighttime flux was characterized by positive NEE suggesting that the photosynthetic dark-cycle flux of cacti was lower than Reco. The discrepancy among the GPP flux estimates stresses the need to understand the limitations of EC and remote sensors, while incorporating complementary monitoring and modelling schemes of nighttime Reco, particularly in the presence of species with different photosynthetic cycles.

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