River metabolism and carbon dynamics in response to flooding in a lowland river

2015 ◽  
Vol 66 (10) ◽  
pp. 919 ◽  
Author(s):  
Robert A. Cook ◽  
Ben Gawne ◽  
Rochelle Petrie ◽  
Darren S. Baldwin ◽  
Gavin N. Rees ◽  
...  
Keyword(s):  
Gross Primary Production ◽  
Carbon Assimilation ◽  
Open Water ◽  
Community Respiration ◽  
Allochthonous Carbon ◽  
Murray River ◽  
Before And After ◽  
Doc Concentration ◽  
Riverine Systems ◽  
Rapid Incorporation

Lowland riverine–floodplain systems often have significant but irregular inputs of allochthonous carbon. However, the importance of this carbon to riverine systems remains poorly understood. We assessed open water dissolved organic carbon (DOC) concentrations, metabolism and biofilm stable isotope (δ13C) signatures, upstream and downstream of an extensive floodplain forest on the Murray River, Australia, before and after a flood event. Prior to flooding, all sites had similar concentrations of DOC, rates of metabolism and biofilm δ13C signatures. During the flood DOC concentration increased up to three-fold downstream of the forest, gross primary production (GPP) increased at all sites, but community respiration (CR) increased only at the downstream sites, resulting in decreased in NPP downstream and a slight increase upstream. Biofilm δ13C signatures became depleted by between 4 and 7‰ downstream of the forest during the flood, reflecting a rapid incorporation of allochthonous carbon into the biofilm. These results indicate that flooding led to a substantial increase to the energy budget of the Murray River through the provisioning of large quantities of allochthonous carbon and that terrestrial carbon was processed within the river biofilms. Allochthonous carbon assimilation within biofilms during flooding provides a potential pathway for allochthonous carbon to be incorporated into the metazoan foodweb.

Quantifying spatiotemporal rhythm of stream metabolism along human disturbance gradients

2020 ◽  
Vol 56 ◽  
pp. 16
Author(s):  
Miraç Eryiğit ◽  
Fatih Evrendilek ◽  
Nusret Karakaya
Keyword(s):  
Gross Primary Production ◽  
Treatment Plant ◽  
Community Respiration ◽  
Stream Metabolism ◽  
Linear Regression Models ◽  
Comparison Results ◽  
Before And After ◽  
The One ◽  
Urban Wastewater Treatment

This study aimed at investigating the effects of the urban wastewater treatment plant (WTP) discharges on the metabolism of Büyüksu Stream (Bolu, Turkey), and modelling the metabolism components as a function of measured environmental variables. Dissolved oxygen (DO) and water temperatures (Tw) were measured to estimate montly stream metabolism in the four reaches: Before and after discharges of the WTP, and the headwaters of Abant Creek and Mudurnu Creek feeding Büyüksu Stream. The DO and Tw measurements were performed for 17 months between August 2015 and December 2016. Metabolism components of community respiration (Rc), gross primary production (GPP) and net ecosystem metabolism (NEM) were estimated by using the two-station method. According to naturality gradient (reach disturbance gradients: before and after discharges, and headwaters of the creeks), mean metabolism components were compared by performing the one-way analysis of variance. The comparison results showed that the WTP discharges increased the average Rc from −30.6 g O2 m−2 day−1 to −130.9 g O2 m−2 day−1, and had no significant impact on the average GPP, statistically (15.6 and 9.1 g O2 m−2 day−1 before and after discharges, respectively). Validations of the multiple non-linear regression models of NEM and Rc gave coefficients of determination of 74.9% and 66.6%, respectively.

Determinants of pelagic metabolism in the Timor Sea during the inter-monsoon period

2011 ◽  
Vol 62 (2) ◽  
pp. 130 ◽  
Author(s):  
A. D. McKinnon ◽  
J. H. Carleton ◽  
S. Duggan
Keyword(s):  
Gross Primary Production ◽  
Vertical Mixing ◽  
Community Respiration ◽  
New Production ◽  
Net Community Production ◽  
Monsoon Period ◽  
Hydrocarbon Seeps ◽  
Timor Sea ◽  
Waves And Tides ◽  
High Production

The Timor Sea is a major conduit of the Indonesian Throughflow characterised by large internal waves and tides. To ascertain whether these result in high pelagic productivity, we conducted experiments to determine the metabolic balance between net community production (NCP) and community respiration (CR) on the Sahul Shelf, the Sahul Shoals and the Yampi Shelf, an area of active hydrocarbon seeps. The barrier to vertical mixing of subthermocline nutrients represented by the halocline allowed new production to dominate in March 2004, whereas production in June 2005 depended on recycled nutrients. CR was correlated with dissolved organic carbon (DOC) in 2004, but with chlorophyll in 2005, suggesting that respiration was dominated by microheterotrophs in 2004 but by autotrophs in 2005. Overall, area-specific CR averaged 120 ± 92 (s.d.), 101 ± 52 and 61 ± 6 mmol O2 m–2 day–1, NCP averaged 109 ± 85 (s.d.), 32 ± 41 and 57 ± 10 mmol O2 m–2 day–1, and average gross primary production (= CR+NCP) : R ratios were 1.9, 1.4 and 1.9 on the shelf, at the Sahul Shoals and the Yampi Shelf, respectively. We suggest that differences in water column structure and internal wave activity drive intermittent high production events in a predominantly oligotrophic sea.

scholarly journals Temperature dependence of planktonic metabolism in the subtropical North Atlantic Ocean

2014 ◽  
Vol 11 (16) ◽  
pp. 4529-4540 ◽  
Author(s):  
L. S. García-Corral ◽  
E. Barber ◽  
A. Regaudie-de-Gioux ◽  
S. Sal ◽  
J. M. Holding ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Temperature Dependence ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Gross Primary Production ◽  
Activation Energies ◽  
Community Respiration ◽  
Metabolic Rates ◽  
Net Community Production ◽  
Different Seasons

Abstract. The temperature dependence of planktonic metabolism in the subtropical North Atlantic Ocean was assessed on the basis of measurements of gross primary production (GPP), community respiration (CR) and net community production (NCP), as well as experimental assessments of the response of CR to temperature manipulations. Metabolic rates were measured at 68 stations along three consecutive longitudinal transects completed during the Malaspina 2010 Expedition, in three different seasons. Temperature gradients were observed in depth and at basin and seasonal scale. The results showed seasonal variability in the metabolic rates, the highest rates being observed during the spring transect. The overall mean integrated GPP / CR ratio was 1.39 ± 0.27 decreasing from winter to summer, and the NCP for the subtropical North Atlantic Ocean during the cruises exhibits net autotrophy (NCP > 0) in about two-thirds (66%) of the total sampled communities. Also, we reported the activation energies describing the temperature dependence of planktonic community metabolism, which was generally higher for CR than for GPP in the subtropical North Atlantic Ocean, as the metabolic theory of ecology predicts. Furthermore, we made a comparison of activation energies describing the responses to in situ temperature in the field (EaCR = 1.64 ± 0.36 eV) and those derived experimentally by temperature manipulations (EaCR = 1.45 ± 0.6 eV), which showed great consistency.

scholarly journals Rates and drivers of Red Sea plankton community metabolism

2018 ◽  
Author(s):  
Daffne C. López-Sandoval ◽  
Katherine Rowe ◽  
Paloma Carillo-de-Albonoz ◽  
Carlos M. Duarte ◽  
Susana Agusti
Keyword(s):  
Red Sea ◽  
Gross Primary Production ◽  
Environmental Drivers ◽  
Community Respiration ◽  
Net Community Production ◽  
Chl A ◽  
Warm Environment ◽  
Increasing Temperature ◽  
Community Production ◽  
Planktonic Communities

Abstract. Resolving the environmental drivers shaping planktonic communities is fundamental to understanding their variability, present and future, across the ocean. More specifically, resolving the temperature-dependence of planktonic communities in low productive waters is essential to predict the response of marine ecosystems to warming scenarios, as ocean warming leads to oligotrophication of the subtropical ocean. Here we quantified plankton metabolic rates along the Red Sea, a unique oligotrophic and warm environment, and analysed the drivers that regulate gross primary production (GPP), community respiration (CR) and the net community production (NCP). The study was conducted on six oceanographic surveys following a north-south transect along Saudi Arabian coasts. Our findings revealed that Chl-a specific GPP and CR rates increased with increasing temperature (R2 = 0.41 and 0.19, respectively, P 

Patterns of dark respiration in aquatic systems

2020 ◽  
Vol 71 (4) ◽  
pp. 432
Author(s):  
Mustafa Mantikci ◽  
Peter A. Staehr ◽  
Jørgen L. S. Hansen ◽  
Stiig Markager
Keyword(s):  
Respiration Rate ◽  
Natural Water ◽  
Water Samples ◽  
Dark Respiration ◽  
Ecosystem Respiration ◽  
Open Water ◽  
Marine Phytoplankton ◽  
Community Respiration ◽  
Coastal Systems ◽  
Natural Water Samples

We used continuous measurements of dissolved oxygen (DO) in dark bottles to characterise patterns of the dark respiration rate (Rdark) for three marine phytoplankton monocultures and in natural-water samples from two marine coastal systems. Furthermore, patterns of ecosystem community respiration rate were determined from open-water changes in DO in a fjord and in a lake. We considered two models of Rdark to describe temporal changes in DO: constant Rdark and decreasing Rdark; increasing Rdark. In addition, the effect of incubation time on Rdark was investigated in bottle incubations. Constant Rdark was observed in short-term (12-h) bottle incubations in natural-water samples from two marine coastal systems. Declining Rdark was observed in marine phytoplankton cultures and open-water measurements in a lake. Increasing Rdark was observed in open-water measurements in a fjord, particularly during summer. Long-term (120-h) bottle incubations in natural-water samples showed an increase in Rdark after 48 and 72h. We show that the conventional expectation of constant rates of respiration in darkness is far from typical, because non-linear changes are common under both controlled experimental conditions, as well as for open-water measurements of ecosystem respiration.

Nanofiltration: improvements of water quality in a large distribution system

2003 ◽  
Vol 3 (1-2) ◽  
pp. 193-200 ◽  
Author(s):  
S. Peltier ◽  
M. Cotte ◽  
D. Gatel ◽  
L. Herremans ◽  
J. Cavard
Keyword(s):  
Water Quality ◽  
Distribution System ◽  
Treatment Plant ◽  
System A ◽  
Physico Chemical ◽  
Before And After ◽  
Doc Concentration ◽  
Improved Stability ◽  
Microbiological Water Quality ◽  
Large Distribution

A nanofiltration (NF) treatment was introduced during the autumn of 1999 in the Méry-sur-Oise treatment plant which feeds the northern Parisian suburbs distribution system. A study was conducted over 4 years to compare the water quality before and after nanofiltration. The results confirmed that NF treatment produced a low DOC concentration in water (average 0.7 mg C/L). This reduction of DOC concentration levels enabled an improved stability of chlorine residual that has been reduced to 0.2 mg/L at the outlet of the plant. The formation of trihalomethanes was thus reduced by 50% in the network. Moreover, the reduction of BDOC enabled an improved biological stability in the water and enhanced the microbiological water quality during distribution. In addition, the NF treatment enhanced the physico-chemical water quality.

scholarly journals Titanium Dioxide (TiO2) nanoparticles more strongly affect bacteria compared to algae in stream ecosystems

2017 ◽  
Vol 6 (1) ◽  
pp. 103-108
Author(s):  
Zachary J. Hough ◽  
Hannah S. Walters ◽  
Heather A. Bechtold
Keyword(s):  
Titanium Dioxide ◽  
Surface Waters ◽  
Gross Primary Production ◽  
Community Respiration ◽  
Stream Ecosystems ◽  
Nano Tio2 ◽  
High Exposure ◽  
Chl A ◽  
Household Products ◽  
Negative Effect

Titanium dioxide (TiO2) is a novel nano-particulate contaminant found in surface waters. Nano-TiO2 is commonly used in numerous pharmaceutical and personal care products ranging from make-up to pill casings, and is an additive in food and household products. Despite the commercialized use of TiO2, its increased presence in surface waters, and toxic effects on stream organsims, little information exists on how nano-TiO2 affects stream ecosystems as a whole. We examined the effect of various concentrations (0.5 - 3 mg/L) of nano-TiO2 on stream ecosystems by measuring the response of algal and microbial communities to acute (12 hr) and chronic (22 day) exposures. We measured gross primary production (GPP), community respiration (CR), and chlorophyll a (chl a) concentrations on intact algae from a local stream.We expected metabolic function of both algal and microbial components of the benthic biofilm to decline with exposure  due to sensitivities to metal oxides. However, we found exposure to any of the concentrations of nano-TiO2 tested caused CR to decrease compared to controls, but, GPP either increased or stayed the same as our controls. We found algal chl a concentraions to increase in the high exposure treatment. Since nano-TiO2 had a negative effect on the microbes, we hypothesized that either autotrophs were released from microbial competition and increased chl a production, or that shading from TiO2 particles may have caused increased chl a production. Additional studies investigating the effects of higher concentrations and longer exposure times to these compounds are warranted.

scholarly journals Dissolved organic carbon release by marine macrophytes

2012 ◽  
Vol 9 (2) ◽  
pp. 1529-1555 ◽  
Author(s):  
C. Barrón ◽  
E. T. Apostolaki ◽  
C. M. Duarte
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Seagrass Meadow ◽  
Gross Primary Production ◽  
The Philippines ◽  
Community Respiration ◽  
Seagrass Meadows ◽  
Macrophyte Communities ◽  
Marine Macrophytes ◽  
Doc Flux

Abstract. Estimates of dissolved organic carbon (DOC) release by marine macrophyte communities (seagrass meadows and macroalgal beds) were obtained experimentally using in situ benthic chambers. The effect of light availability on DOC release by macrophyte communities was examined in two communities both by comparing net DOC release under light and dark, and by examining the response of net DOC release to longer-term (days) experimental shading of the communities. All most 85% of the seagrass communities and almost all of macroalgal communities examined acted as net sources of DOC. There was a weak tendency for higher DOC fluxes under light than under dark conditions in seagrass meadow. There is no relationship between net DOC fluxes and gross primary production (GPP) and net community production (NCP), however, this relationship is positive between net DOC fluxes and community respiration. Net DOC fluxes were not affected by shading of a T. testudinum community in Florida for 5 days, however, shading of a mixed seagrass meadow in the Philippines led to a significant reduction on the net DOC release when shading was maintained for 6 days compared to only 2 days of shading. Based on published and unpublished results we also estimate the global net DOC production by marine macrophytes. The estimated global net DOC flux, and hence export, from marine macrophyte is about 0.197 ± 0.015 Pg C yr−1 or 0.212 ± 0.016 Pg C yr−1 depending if net DOC flux by seagrass meadows was estimated by taking into account the low or high global seagrass area, respectively.

Synthesis of canine seromucoid before and after total hepatectomy

1962 ◽  
Vol 202 (6) ◽  
pp. 1087-1089 ◽  
Author(s):  
John C. Kukral ◽  
Ronald J. Pancner ◽  
June Louch ◽  
Richard J. Winzler
Keyword(s):  
Perchloric Acid ◽  
Incorporation Rate ◽  
One Stage ◽  
Before And After ◽  
Extrahepatic Tissues ◽  
Rapid Incorporation

The incorporation rate of S35 DL-methionine into the perchloric acid-soluble (seromucoid) fraction of serum was studied in the same four dogs before and after a one-stage total hepatectomy. This incorporation rate was used as an index of seromucoid synthesis. In all dogs before hepatectomy there was a rapid incorporation rate reaching a maximum synthesis in approximately 6 hr after injection. After hepatectomy the average incorporation rate was reduced to about one-third of prehepatectomy levels. It is concluded that in the dog most of the perchloric acid-soluble (seromucoid) fraction is of hepatic origin whereas a smaller part is synthesized by extrahepatic tissues.

scholarly journals Patterns in planktonic metabolism in the Mediterranean Sea

2009 ◽  
Vol 6 (12) ◽  
pp. 3081-3089 ◽  
Author(s):  
A. Regaudie-de-Gioux ◽  
R. Vaquer-Sunyer ◽  
C. M. Duarte
Keyword(s):  
Mediterranean Sea ◽  
Gross Primary Production ◽  
Western Mediterranean ◽  
Early Summer ◽  
Late Spring ◽  
Community Respiration ◽  
Net Community Production ◽  
R Ratio ◽  
The Mediterranean ◽  
Community Production

Abstract. Planktonic gross community production (GPP), net community production (NCP) and community respiration (CR) across the Mediterranean Sea was examined in two cruises, Thresholds 2006 and 2007, each crossing the Mediterranean from West to East to test for consistent variation along this longitudinal gradient in late spring to early summer. GPP averaged 2.4±0.4 mmol O2 m−3 d−1, CR averaged 3.8±0.5 mmol O2 m−3 d−1, and NCP averaged – 0.8±0.6 mmol O2 m−3 d−1 across the studied sections, indicative of a tendency for a net heterotrophic metabolism in late spring to early summer, prevalent across studied sections of the Mediterranean Sea as reflected in 70% of negative NCP estimates. The median P/R ratio was 0.6, also indicating a strong prevalence of heterotrophic communities (P/R<1) along the studied sections of the Mediterranean Sea. The communities tended to be net heterotrophic (i.e. P/R<1) at GPP less than 2.8 mmol O2 m−3 d−1. The Western Mediterranean tended to support a higher gross primary production and community respiration than the Eastern basin did, but these differences were not statistically significant (t-test, p>0.05). The net heterotrophy of the studied sections of the Mediterranean Sea indicates that allochthonous carbon should be important to subsidise planktonic metabolism during the late spring.

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