Spatial and seasonal variability of surface particulate inorganic carbon and relationship with particulate organic carbon in the Yellow-Bohai Sea

2020 ◽  
Vol 76 (5) ◽  
pp. 327-339
Author(s):  
Xiujun Wang ◽  
Jun Yu ◽  
Hang Fan
2008 ◽  
Vol 5 (6) ◽  
pp. 1615-1623 ◽  
Author(s):  
S. Fiedler ◽  
B. S. Höll ◽  
A. Freibauer ◽  
K. Stahr ◽  
M. Drösler ◽  
...  

Abstract. Numerous studies have dealt with carbon (C) contents in Histosols, but there are no studies quantifying the relative importance of the individual C components in pore waters. For this study, measurements were taken of all the carbon components (particulate organic carbon, POC; dissolved organic carbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH4) in the soil pore water of calcareous fens under three different water management regimes (re-wetted, deeply and moderately drained). Pore water was collected weekly or biweekly (April 2004 to April 2006) at depths between 10 and 150 cm. The main results obtained were: (1) DIC (94–280 mg C l−1) was the main C-component. (2) POC and DOC concentrations in the pore water (14–125 mg C l−1 vs. 41–95 mg C l−1) were pari passu. (3) Dissolved CH4 was the smallest C component (0.005–0.9 mg C l−1). Interestingly, about 30% of the POM particles were colonized by microbes indicating that they are active in the internal C turnover. Certainly, both POC and DOC fractions are essential components of the C budget of peatlands. Furthermore, dissolved CO2 in all forms of DIC appears to be an important part of peatland C-balance.


2020 ◽  
Vol 12 (5) ◽  
pp. 840 ◽  
Author(s):  
Dabin Lee ◽  
SeungHyun Son ◽  
HuiTae Joo ◽  
Kwanwoo Kim ◽  
Myung Joon Kim ◽  
...  

In recent years, the change of marine environment due to climate change and declining primary productivity have been big concerns in the East/Japan Sea, Korea. However, the main causes for the recent changes are still not revealed clearly. The particulate organic carbon (POC) to chlorophyll-a (chl-a) ratio (POC:chl-a) could be a useful indicator for ecological and physiological conditions of phytoplankton communities and thus help us to understand the recent reduction of primary productivity in the East/Japan Sea. To derive the POC in the East/Japan Sea from a satellite dataset, the new regional POC algorithm was empirically derived with in-situ measured POC concentrations. A strong positive linear relationship (R2 = 0.6579) was observed between the estimated and in-situ measured POC concentrations. Our new POC algorithm proved a better performance in the East/Japan Sea compared to the previous one for the global ocean. Based on the new algorithm, long-term POC:chl-a ratios were obtained in the entire East/Japan Sea from 2003 to 2018. The POC:chl-a showed a strong seasonal variability in the East/Japan Sea. The spring and fall blooms of phytoplankton mainly driven by the growth of large diatoms seem to be a major factor for the seasonal variability in the POC:chl-a. Our new regional POC algorithm modified for the East/Japan Sea could potentially contribute to long-term monitoring for the climate-associated ecosystem changes in the East/Japan Sea. Although the new regional POC algorithm shows a good correspondence with in-situ observed POC concentrations, the algorithm should be further improved with continuous field surveys.


2008 ◽  
Vol 5 (3) ◽  
pp. 2049-2073
Author(s):  
S. Fiedler ◽  
B. S. Höll ◽  
A. Freibauer ◽  
K. Stahr ◽  
M. Drösler ◽  
...  

Abstract. Numerous studies have dealt with carbon (C) concentrations in Histosols, but there are no studies quantifying the relative importance of all individual C components in pore waters. For this study, measurements were made of all the carbon components (i.e., particulate organic carbon, POC; dissolved organic carbon, DOC; dissolved inorganic carbon, DIC; dissolved methane, CH4) in the soil pore water of a calcareous fen under three different water management regimes (re-wetted, deeply and moderately drained). Pore water was collected weekly or biweekly (April 2004 to April 2006) at depths between 10 and 150 cm. The main results obtained were: (1) DIC (94–280 mg C l−1) was the main C-component. (2) POC and DOC concentrations in the pore water (14–125 mg C l−1 vs. 41–95 mg C l−1) were pari passu. (3) Dissolved CH4 was the smallest C component (0.005–0.9 mg C l−1). Interestingly, about 30% of the POM particles were colonized by microbes indicating that they are active in the internal C transfer in the soil profile ("C-Shuttles"). Consequently, it was concluded that POC is at least as important as DOC for internal soil C turnover. There is no reason to assume significant biochemical differences between POC and DOC as they only differ in size. Therefore, both POC and DOC fractions are essential components of C budgets of peatlands. Furthermore dissolved CO2 in all forms of DIC apparently is an important part of peatland C-balances.


2021 ◽  
Author(s):  
John Barry Gallagher ◽  
Vishnu Prahalad ◽  
John Aalders

Abstract Total organic carbon (TOC) sediment stocks as a CO2 mitigation service require exclusion of allochthonous black (BC) and particulate inorganic carbon corrected for water–atmospheric equilibrium (PICeq). For the first time, we address this bias for a temperate salt marsh and a coastal tropical seagrass in BC hotspots that represent two different blue carbon ecosystems of Malaysia and Australia. Seagrass TOC stocks were similar to the salt marshes with soil depths < 1 m (59.3 ± 11.3 and 74.9 ± 18.9 MgC ha− 1, CI 95% respectively). Both ecosystems showed larger BC constraints than their pristine counterparts did. However, the seagrass meadows’ mitigation services were largely constrained by both higher BC/TOC and PICeq/TOC fractions (38.0% ± 6.6% and 43.4% ± 5.9%, CI 95%) and salt marshes around a third (22% ± 10.2% and 6.0% ± 3.1% CI 95%). The results provide useful data from underrepresented regions, and, reiterates the need to consider both BC and PIC for more reliable blue carbon mitigation assessments.


2019 ◽  
Author(s):  
Wim Joost van Hoek ◽  
Lauriane Vilmin ◽  
Arthur H. W. Beusen ◽  
José M. Mogollón ◽  
Xiaochen Liu ◽  
...  

Abstract. Here, we present the implementation of the freshwater carbon (C) cycle in the Dynamic In-stream Chemistry module (CARBON-DISC), which is part of the Integrated Model to Assess the Global Environment-Dynamic Global Nutrient Model (IMAGE-DGNM). A coupled hydrology-biogeochemistry approach with 0.5 by 0.5-degree resolution accounts for the spatial and temporal variability in dynamic conditions in the aquatic continuum using independent global databases. This process-based model resolves the concentrations, transformations and transfer fluxes of dissolved inorganic carbon (DIC), dissolved organic carbon (DOC) and terrestrial and autochthonous particulate organic carbon (POC) from headwaters to river mouth with a time step of 1 month for the period 1950–2000. This is a major step forward in basin scale modelling of the C processing in freshwater systems, since simulated results can be validated at every location and point in time, and the model can be applied for retrodiction and to analyse future scenarios. Validation of the model with long-term measurement data shows a fair agreement, considering that this is a global model. To analyse the performance of the full production-respiration DISC module, two other schemes are presented, including an abiotic system excluding any in-stream processing of DOC and allochthonous production, and an extended abiotic system including heterotrophic respiration, but excluding production. Furthermore, a sensitivity analysis shows that many parameters, such as temperature, solar radiation, organic sediment mineralization rate and C inputs, including particulate organic carbon from terrestrial vegetation and dissolved inorganic carbon from groundwater, strongly affect atmosphere-freshwater exchange of CO2.


2012 ◽  
Vol 9 (10) ◽  
pp. 4155-4167 ◽  
Author(s):  
M. N. Müller ◽  
L. Beaufort ◽  
O. Bernard ◽  
M. L. Pedrotti ◽  
A. Talec ◽  
...  

Abstract. Coccolithophores, a key phytoplankton group, are one of the most studied organisms regarding their physiological response to ocean acidification/carbonation. The biogenic production of calcareous coccoliths has made coccolithophores a promising group for paleoceanographic research aiming to reconstruct past environmental conditions. Recently, geochemical and morphological analyses of fossil coccoliths have gained increased interest in regard to changes in seawater carbonate chemistry. The cosmopolitan coccolithophore Emiliania huxleyi (Lohm.) Hay and Mohler was cultured over a range of pCO2 levels in controlled laboratory experiments under nutrient replete and nitrogen limited conditions. Measurements of photosynthesis and calcification revealed, as previously published, an increase in particulate organic carbon production and a moderate decrease in calcification from ambient to elevated pCO2. The enhancement in particulate organic carbon production was accompanied by an increase in cell diameter. Changes in coccolith volume were best correlated with the coccosphere/cell diameter and no significant correlation was found between the coccolith volume and the particulate inorganic carbon production. The conducted experiments revealed that the coccolith volume of E. huxleyi is variable with aquatic CO2 concentration but its sensitivity is rather small in comparison with its sensitivity to nitrogen limitation. Comparing coccolith morphological and geometrical parameters like volume, mass and size to physiological parameters under controlled laboratory conditions is an important step to understand variations in fossil coccolith geometry.


2020 ◽  
Author(s):  
John Barry Gallagher ◽  
Vishnu Prahalad ◽  
John Aalders

AbstractTotal organic carbon (TOC) sediment stocks as a CO2 mitigation service requires exclusion of allochthonous black (BC) and particulate inorganic carbon corrected for water– atmospheric equilibrium (PICeq). For the first time, we address this bias for a temperate salt marsh and a coastal tropical seagrass in BC hotspots. Seagrass TOC stocks were similar to the salt marshes with soil depths < 1 m (59.3 ± 11.3 and 74.9 ± 18.9 MgC ha-1, CI 95% respectively) and sequestration rates of 1.134 MgC ha-1 yr-1. Both ecosystems showed larger BC constraints than their pristine counterparts. However, the seagrass meadows’ mitigation services were largely constrained by both higher BC/TOC and PICeq/TOC fractions (38.0% ± 6.6% and 43.4% ± 5.9%, CI 95%) and salt marshes around a third (22% ± 10.2% and 6.0% ± 3.1% CI 95%). The results demonstrate a need to account for both BC and PIC within blue carbon mitigation assessments.


2010 ◽  
Vol 7 (3) ◽  
pp. 1109-1116 ◽  
Author(s):  
M. N. Müller ◽  
K. G. Schulz ◽  
U. Riebesell

Abstract. The physiological performance of two coccolithophore species, Emiliania huxleyi and Coccolithus braarudii, was investigated during long-term exposure to elevated pCO2 levels. Mono-specific cultures were grown over 152 (E. huxleyi) and 65 (C. braarudii) generations while pCO2 was gradually increased to maximum levels of 1150 μatm (E. huxleyi) and 930 μatm (C. braarudii) and kept constant thereafter. Rates of cell growth and cell quotas of particulate organic carbon (POC), particulate inorganic carbon (PIC) and total particulate nitrogen (TPN) were determined repeatedly throughout the incubation period. Increasing pCO2 caused a decrease in cell growth rate of 9% and 29% in E. huxleyi and C. braarudii, respectively. In both species cellular PIC:TPN and PIC:POC ratios decreased in response to rising pCO2, whereas no change was observed in the POC:TPN ratios of E. huxleyi and C. braarudii. These results are consistent with those obtained in shorter-term high CO2 exposure experiments following abrupt pertubations of the seawater carbonate system and indicate that for the strains tested here a gradual CO2 increase does not alleviate CO2/pH sensitivity.


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