Treated Wastewater Changes the Export of Dissolved Inorganic Carbon and Its Isotopic Composition and Leads to Acidification in Coastal Oceans

2018 ◽  
Vol 52 (10) ◽  
pp. 5590-5599 ◽  
Author(s):  
Xufeng Yang ◽  
Liang Xue ◽  
Yunxiao Li ◽  
Ping Han ◽  
Xiangyu Liu ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Treated Wastewater ◽  
Coastal Oceans

scholarly journals Evaluating Dissolved Inorganic Carbon Cycling in a Forested Lake Watershed Using Carbon Isotopes

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 636-645 ◽  
Author(s):  
Ramon Aravena ◽  
S. L. Schiff ◽  
S. E. Trumbore ◽  
P. J. Dillon ◽  
Richard Elgood
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotopes ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Isotopic Composition ◽  
Isotopic Fractionation ◽  
Early Spring ◽  
Late Winter ◽  
Isotope Pattern ◽  
Carbon Isotopic

Dissolved inorganic carbon (DIC) is the main acid buffer in forested lake watersheds in Canada. We used carbon isotopes (13C, 14C) to evaluate the production and cycling of DIC in an acid-sensitive lake watershed of the Precambrian Shield. Soil CO2, groundwater and stream DIC were characterized chemically and isotopically. Soil CO2 concentration profiles reflect both changes in production and in losses due to diffusion. δ13C soil CO2 profiles (δ13C values of −23‰ in summer, slightly enriched during the fall and −25%‰ during the winter) are a reflection of the isotopic composition of the sources and changes in isotopic fractionation due to diffusion. Carbon isotopic composition (13C, 14C) of the groundwater and stream DIC clearly indicate that weathering of silicates by soil CO2 is the main source of DIC in these watersheds. 14C data show that, in addition to recent groundwater, an older groundwater component with depleted 14C activity is also present in the bedrock. The carbon isotope pattern in the groundwater also implies that, besides the main springtime recharge events, contributions to the groundwater may also occur during late winter/early spring.

scholarly journals On the Isotopic Composition of Dissolved Inorganic Carbon in Rivers and Shallow Groundwater: A Diagrammatic Approach to Process Identification and A More Realistic Model of the Open System

Radiocarbon ◽  
1997 ◽  
Vol 39 (3) ◽  
pp. 251-268 ◽  
Author(s):  
C. B. Taylor
Keyword(s):  
Steady State ◽  
New Zealand ◽  
Isotopic Composition ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Dynamic Balance ◽  
Shallow Groundwater ◽  
Realistic Model ◽  
Essential Information ◽  
Aquifer Systems

Rivers and shallow groundwater are deep groundwater precursors. Their dissolved inorganic carbon content (DIC) and its isotopic composition are end members in the evolution of these properties in confined situations, and are therefore essential information when applying carbon isotopes as tracers of groundwater processes and determining aquifer residence times using 14C.During studies of regional aquifer systems in New Zealand, a simple model has been developed to explain the isotopic compositions of DIC encountered in rivers and shallow groundwater. The model format incorporates a diagrammatic approach, providing a framework for tracing the subsequent evolution of DIC in both precipitation- and river-recharged aquifers under closed conditions.DIC concentration of rivers continuously adjusts toward chemical and isotopic equilibrium between direct addition of CO2 to the water (via plant respiration and decay of dead organic material) and exchange of CO2 across the river-air interface. In the shallow groundwater situation, the gaseous reservoir is soil CO2, generally at significantly higher partial pressure. In both cases, calcite dissolution or other processes may be an additional source of DIC directly added to the bicarbonate and dissolved CO2 components; while these may add or remove DIC, steady-state isotopic concentrations are considered to be determined only by the dynamic balance between directly added CO2 and gas exchange. This model allows the calculation of steady states, using selectable parameters in river or groundwater situations. These appear as straight lines in 13C or 14C vs. 1/DIC, or total 14C vs. DIC plots, into which the experimental data can be inserted for interpretation. In the case of 14C, the steady-state balance is very often complicated by the presence of an old component in the directly added DIC; the understanding achieved via the 13C patterns is helpful in recognizing this.Data from four contrasting aquifer systems in New Zealand. The success of the approach has depended crucially on DIC concentrations measured very accurately on the isotope samples, rather than separate chemical analyses.

scholarly journals Differences in metabolic rate between two Atlantic cod (Gadus morhua) populations estimated with carbon isotopic composition in otoliths

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248711
Author(s):  
Szymon Smoliński ◽  
Côme Denechaud ◽  
Gotje von Leesen ◽  
Audrey J. Geffen ◽  
Peter Grønkjær ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Gadus Morhua ◽  
Inorganic Carbon ◽  
Atlantic Cod ◽  
Dissolved Inorganic Carbon ◽  
Physiological State ◽  
Carbon Isotopic Composition ◽  
Physiological Basis ◽  
Carbon Isotopic ◽  
Growth Increments

The isotopic composition of inorganic carbon in otoliths (δ13Coto) can be a useful tracer of metabolic rates and a method to study ecophysiology in wild fish. We evaluated environmental and physiological sources of δ13Coto variation in Icelandic and Northeast Arctic (NEA) cod (Gadus morhua) over the years 1914–2013. Individual annual growth increments of otoliths formed at age 3 and 8 were micromilled and measured by isotope-ratio mass spectrometry. Simultaneously, all annual increment widths of the otoliths were measured providing a proxy of fish somatic growth. We hypothesized that changes in the physiological state of the organism, reflected by the isotopic composition of otoliths, can affect the growth rate. Using univariate and multivariate mixed-effects models we estimated conditional correlations between carbon isotopic composition and growth of fish at different levels (within individuals, between individuals, and between years), controlling for intrinsic and extrinsic effects on both otolith measurements. δ13Coto was correlated with growth within individuals and between years, which was attributed to the intrinsic effects (fish age or total length). There was no significant correlation between δ13Coto and growth between individuals, which suggests that caution is needed when interpreting δ13Coto signals. We found a significant decrease in δ13Coto through the century which was explained by the oceanic Suess effect-admixture of isotopically light carbon from fossil fuel. We calculated the proportion of the respired carbon in otolith carbonate (Cresp) using carbon isotopic composition in diet and dissolved inorganic carbon of the seawater. This approach allowed us to correct the values for each stock in relation to these two environmental baselines. Cresp was on average 0.275 and 0.295 in Icelandic and NEA stock, respectively. Our results provide an insight into the physiological basis for differences in growth characteristics between these two cod stocks, and how that may vary over time.

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