scholarly journals Fluxes of particulate matter, carbonates, organic carbon and nitrogen in the northern Adriatic continental shelf: A synthesis overview

2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Michele Giani ◽  
Juan Carlos Miquel ◽  
Amelia De Lazzari ◽  
Alfredo Boldrin
Keyword(s):  
Organic Matter ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Primary Production ◽  
Sediment Traps ◽  
Transport Processes ◽  
Advective Transport ◽  
Northern Adriatic ◽  
Benthic Respiration ◽  
Time Space

Time series of composition and fluxes of settling particles in the marine environment, obtained by sediment traps, contribute to define the main processes driving the dynamics of particulate matter and of the time/space variability of benthic-pelagic exchanges. With this aim, the composition and seasonal and annual fluxes of settling matter, obtained from different projects and from published papers, at 8 sites of the Northern Adriatic shelf were estimated.  The mean yearly particulate fluxes varied from 2763 to 14,447 g m-2 y-1, from 66 to 236 gC m-2y-1 for organic carbon (OC) flux, from 861 to 7525 g m-2y-1 for carbonates and from 12 to 42 gN m-2y-1 for nitrogen (N). The fluxes were characterized by high seasonal variations with marked increase in autumn or in winter with respect to spring or summer. The sink of particles occurs in relatively short episodes as about 50% of annual particle flux settles in less than 1-2 months in the western coastal area. This seasonality can be related to the riverine discharges, primary production and wind regimes of the basin. Utilizing the N/OC ratio as an index for discriminating the different origin of organic matter (i.e., resuspended/riverine and autochthonous), the primary marine carbon flux was estimated to range from 10 to 28% of the OC fluxes and accounted for 8-40% of the primary production, depending on the site. Then, due to the shallow waters of the basin and to the relevant riverine inputs, the total fluxes near the sea bottom were highly dependent on resuspension and advective transport processes. The important contribution of these last processes as source of organic matter is suggested also by the comparison between fluxes determined by sediment traps with mass accumulation rates (MAR) in sediments, derived from radionuclide measurements. Indeed, the fraction of OC fluxes which is not buried in the sediment is sufficient to support the benthic respiration processes.

scholarly journals Downward fluxes of sinking particulate matter in the deep Ionian Sea (NESTOR site), eastern Mediterranean: seasonal and interannual variability

2013 ◽  
Vol 10 (11) ◽  
pp. 7235-7254 ◽  
Author(s):  
S. Stavrakakis ◽  
A. Gogou ◽  
E. Krasakopoulou ◽  
A. P. Karageorgis ◽  
H. Kontoyiannis ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Organic Carbon ◽  
Primary Production ◽  
Interannual Variability ◽  
Primary Productivity ◽  
Mass Flux ◽  
Total Mass ◽  
Sediment Traps ◽  
Ionian Sea ◽  
Seasonal And Interannual Variability

Abstract. In order to assess seasonal and interannual variability in the export of particulate matter and its main constituents, sediment traps were deployed at five successive depths from February 2006 to March 2010 in the deepest basin of the Mediterranean (SE Ionian Sea, NESTOR site). The average total mass fluxes were 66, 58, 54, 34, and 52 mg m−2 d−1, at 700, 1200, 2000, 3200, and 4300 m, respectively. The temporal variations of the mass flux showed similar seasonal signal at all sampling depths with higher values in spring–summer and lower in autumn–winter. Changes in the main constituents of the mass flux (organic carbon, carbonates, opal, and lithogenic matter) largely followed the same temporal variability with total mass flux, revealing mechanisms of rapid vertical (top-down) transport from 700 m down to 4300 m depth. Lateral inputs at the deepest trap are probably of importance, attributed to the influence of the deep Adriatic water, characterized by relatively higher turbidity than overlying water masses. Two major processes seem to control the seasonal mass flux variability: (a) primary productivity at the euphotic zone; and (b) episodic dust input events. Primary productivity shows two maxima during late winter/early spring and late spring/summer, as witnessed by the organic carbon, carbonate, and opal fluxes in the mesopelagic and bathypelagic layers, whereas the influence of dust inputs is evidenced by enhanced lithogenic fluxes occurring during spring and summer. The interannual variability generally shows a gradual increase of fluxes during the time frame of the experiment. Both seasonal and interannual variability of mass flux are associated with variations in the intensity and position of the neighboring Pelops anticyclonic gyre, which appears to affect the upwelling of intermediate, nutrient-rich waters and subsequently the surface productivity. Combination of estimated satellite and algorithm-generated primary production data for the Ionian Sea, calculated POC fluxes out of the euphotic layer and POC fluxes measured by sediment traps at the mesopelagic and bathypelagic layers of NESTOR site during our 4 yr experiment, reveal that only a small portion of primary production (0.46%) reaches at 3200 m, corresponding to a mean annual carbon export of 1.12 g C m−2 yr−1.

Constant current chronopotentiometric stripping characterisation of organic matter in seawater from the northern Adriatic, Croatia

2014 ◽  
Vol 11 (2) ◽  
pp. 158 ◽  
Author(s):  
Slađana Strmečki ◽  
Jelena Dautović ◽  
Marta Plavšić
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Seasonal Changes ◽  
Electrochemical Techniques ◽  
Organic Matter Content ◽  
Matter Content ◽  
Constant Current ◽  
Po River ◽  
Northern Adriatic ◽  
Catalytically Active

Environmental context We determined seasonal changes in the organic matter content of the northern Adriatic with newly applied electrochemical techniques able to measure catalytically active organics. The inflow of the Po River and its nutrient load are responsible for the observed changes in the type and concentrations of organic matter in the area. Abstract Catalytically active polysaccharides (Cat PSs) and nitrogen-containing polymeric organic material (N-POM) were determined in seawater from the northern Adriatic station ST101. Catalytically active organics were measured by applying electrochemical methods of adsorptive transfer chronopotentiometric stripping with medium exchange and chronopotentiometric stripping in unmodified seawater. Their concentrations were expressed in milligrams per cubic decimetre–3--> of equivalents of the model calibrating substances, polysaccharide xanthan and protein human serum albumin. The optimal electroanalytical conditions for determination of Cat PSs in seawater were evaluated and defined. Seasonal changes of Cat PSs and N-POM were observed during the period 2011–2013. The highest values were determined in the spring–summer period and the lowest in winter. Cat PSs and N-POM were present in both the dissolved and particulate organic carbon fractions. Cat PSs and N-POM showed a statistically significant positive correlation with the concentrations of surface-active substances. A weak but statistically significant correlation was found between Cat PSs and dissolved organic carbon concentrations. Copper complexing capacities in the period 2011–2013 were in the range of 41–130nmoldm–3.

scholarly journals Pulsed carbon export from mountains by earthquake-triggered landslides explored in a reduced-complexity model

2021 ◽  
Vol 9 (4) ◽  
pp. 823-844
Author(s):  
Thomas Croissant ◽  
Robert G. Hilton ◽  
Gen K. Li ◽  
Jamie Howarth ◽  
Jin Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Annual Runoff ◽  
Transport Processes ◽  
Mountain Range ◽  
Biogeochemical Processes ◽  
Organic Matter Degradation ◽  
Carbon Export ◽  
Model Framework ◽  
Mountain Ranges

Abstract. In mountain ranges, earthquakes can trigger widespread landsliding and mobilize large amounts of organic carbon by eroding soil and vegetation from hillslopes. Following a major earthquake, the landslide-mobilized organic carbon can be exported from river catchments by physical sediment transport processes or stored within the landscape where it may be degraded by heterotrophic respiration. The competition between these physical and biogeochemical processes governs a net transfer of carbon between the atmosphere and sedimentary organic matter, yet their relative importance following a large landslide-triggering earthquake remains poorly constrained. Here, we propose a model framework to quantify the post-seismic redistribution of soil-derived organic carbon. The approach combines predictions based on empirical observations of co-seismic sediment mobilization with a description of the physical and biogeochemical processes involved after an earthquake. Earthquake-triggered landslide populations are generated by randomly sampling a landslide area distribution, a proportion of which is initially connected to the fluvial network. Initially disconnected landslide deposits are transported downslope and connected to rivers at a constant velocity in the post-seismic period. Disconnected landslide deposits lose organic carbon by heterotrophic oxidation, while connected deposits lose organic carbon synchronously by both oxidation and river export. The modeling approach is numerically efficient and allows us to explore a large range of parameter values that exert a control on the fate of organic carbon in the upland erosional system. We explore the role of the climatic context (in terms of mean annual runoff and runoff variability) and rates of organic matter degradation using single pool and multi-pool models. Our results highlight the fact that the redistribution of organic carbon is strongly controlled by the annual runoff and the extent of landslide connection, but less so by the choice of organic matter degradation model. In the context of mountain ranges typical of the southwestern Pacific region, we find that model configurations allow more than 90 % of the landslide-mobilized carbon to be exported from mountain catchments. A simulation of earthquake cycles suggests efficient transfer of organic carbon out of a mountain range during the first decade of the post-seismic period. Pulsed erosion of organic matter by earthquake-triggered landslides is therefore an effective process to promote carbon sequestration in sedimentary deposits over thousands of years.

The vertical flux of particulate matter in the polynya of Terra Nova Bay. Part II. Biological components

2003 ◽  
Vol 15 (2) ◽  
pp. 175-188 ◽  
Author(s):  
A. ACCORNERO ◽  
C. MANNO ◽  
F. ESPOSITO ◽  
M.C. GAMBI
Keyword(s):  
Organic Matter ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Total Mass ◽  
Ross Sea ◽  
Late Summer ◽  
Faecal Pellets ◽  
Terra Nova Bay ◽  
Biogenic Carbon ◽  
Terra Nova

Downward fluxes of particulate matter were investigated in the polynya of Terra Nova Bay (western Ross Sea) from February 1995 to December 1997. The main biological components were siliceous phytoplankton (diatoms, silicoflagellates and parmales), abundant faecal pellets of several types and zooplankton (mainly shelled pteropods). Vertical fluxes of particles occurred mainly through diatoms and faecal pellets in the first and second part of the summer, respectively. The highest fluxes were recurrently observed in late summer, when faeces contributed up to 100% of organic carbon. Unusually high fluxes were recorded in winter 1995, when faecal pellets accounted for 84.6% of the organic carbon. Peak fluxes were always driven by the sinking of faecal pellets, that hence appear to be the most efficient vector of export in the polynya of Terra Nova Bay. A major flux component was the pteropod Limacina helicina, which repeatedly sank in high amounts after the growing season. In April–June, L. helicina probably transported biogenic carbon to deep layers as a passive sinker. The inclusion of pteropods in flux estimates resulted in values that were up to 20 (for total mass), 25 (for organic matter) and 48 (for carbonate) times higher than the previously measured fluxes. Fluxes are known to be biased by swimmers, but ultimately attention must be paid to a possible erroneous categorization of some zooplankton as swimmers to avoid severe underestimation of fluxes of total mass (up to 95% in our study), organic matter (up to 96%) and carbonate (up to 100%).

Seasonal Transport Characteristics of Suspended Particulate Organic Carbon in the Middle and Lower Yangtze River and the Relationship with Three Georges Reservoir

2013 ◽  
Vol 663 ◽  
pp. 1058-1063 ◽  
Author(s):  
Xiao Li Liu ◽  
Shou Ye Yang ◽  
Wen Rui Huang ◽  
Lin Lu Li ◽  
Chen Zeng ◽  
...  
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Suspended Matter ◽  
Yangtze River ◽  
Three Gorges ◽  
The Three Gorges ◽  
Suspended Particulate

The suspended matter samples collected about 2 times every month in Datong of Yangtze River from May to November 2010 were used for determination of grain size and particulate organic carbon (POC) component. The results indicated that the size composition and organic carbon concentrations of Datong showed obvious seasonal characteristics. The median grain size of the suspended particulate matter ranged from 5.8 to 7.8Φ, decreased in summer (July to September) and increased in autumn (October to November). The POC% of the suspended particulate matter ranged from 0.87% to 1.18%, and was lower in summer, because high sediment discharge had dilution effect for organic carbon. The increase of the turbidity of water reduced the production capacity, and the organic matter correspondingly decreased. POC% decreased with the reduction of median grain size, which suggested that organic matter into the river in summer is mainly organic debris, but not mainly absorbed by the fine particles of clay. CaCO3 content ranged 3.7% to 7.6% and was higher in summer, which reflected the increased source contribution of the upper stream. It decreased in autumn, which reflected the increased source contribution of the middle and lower stream. Since the impoundment of the Three Gorges Reservoir, POC% in Datong were significantly higher than before, which showed the rise of fine particulate matter component and its stronger adsorption of organic matter. The Three Gorges Dam had significant influence on the grain size and organic composition of suspended matter of theYangtze River into the sea. Its potential environmental impact of bio-geochemical effects deserves more research attention.

Primary production dynamics of dominant hydrophytes in Lake Provala (Serbia)

2009 ◽  
Vol 4 (2) ◽  
pp. 250-257 ◽  
Author(s):  
Ljiljana Nikolić ◽  
Slobodanka Pajević ◽  
Branka Ljevnaić
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Primary Production ◽  
Chlorophyll A ◽  
Myriophyllum Spicatum ◽  
Open Water ◽  
Maximum Growth ◽  
Vegetation Period ◽  
Ceratophyllum Demersum ◽  
Chl A

AbstractThe objective of this investigation was to analyze the primary production of the dominant hydrophytes by monitoring levels of organic matter and organic carbon and estimating photosynthetic potential via the total chlorophyll content. The survey was conducted in Lake Provala (Serbia) throughout the peak vegetation period of the year 2000. The contents of organic matter and organic carbon for Myriophyllum spicatum L. were 105.11 g m−2 and 73.66 g m−2, Nymphoides peltata (Gmel.) Kunt. were 95.51 g m−2 and 45.26 g m−2 and Ceratophyllum demersum L. were 52.17 g m−2 and 29.75 g m−2. Chlorophyll A (Chl a) and chlorophyll A+B (Chl a+b) pigments ranged from 1.54 mg g−1(Chl a) and 2.1 mg g−1(Chl a+b) in M. spicatum to 5.27 mg g−1(Chl a) and 7.53 mg g−1(Chl a+b) in C. demersum. At full leaf out, the latter aquatic plants exceeded 50% cover of the open water surface. All species achieved maximum growth in June, but significant differences in growth dynamics were observed. At the end of the vegetation period, these plants sink to the bottom and decompose

scholarly journals Chemical characterization of fine particulate matter in Changzhou, China, and source apportionment with offline aerosol mass spectrometry

2017 ◽  
Vol 17 (4) ◽  
pp. 2573-2592 ◽  
Author(s):  
Zhaolian Ye ◽  
Jiashu Liu ◽  
Aijun Gu ◽  
Feifei Feng ◽  
Yuhai Liu ◽  
...  
Keyword(s):  
Trace Elements ◽  
Organic Matter ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Source Apportionment ◽  
Fine Particulate Matter ◽  
Chemical Characterization ◽  
Water Soluble ◽  
Aerosol Mass ◽  
Fine Particulate

Abstract. Knowledge of aerosol chemistry in densely populated regions is critical for effective reduction of air pollution, while such studies have not been conducted in Changzhou, an important manufacturing base and populated city in the Yangtze River Delta (YRD), China. This work, for the first time, performed a thorough chemical characterization on the fine particulate matter (PM2.5) samples, collected during July 2015 to April 2016 across four seasons in this city. A suite of analytical techniques was employed to measure the organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble inorganic ions (WSIIs), trace elements, and polycyclic aromatic hydrocarbons (PAHs) in PM2.5; in particular, an Aerodyne soot particle aerosol mass spectrometer (SP-AMS) was deployed to probe the chemical properties of water-soluble organic aerosol (WSOA). The average PM2.5 concentration was found to be 108.3 µg m−3, and all identified species were able to reconstruct ∼ 80 % of the PM2.5 mass. The WSIIs occupied about half of the PM2.5 mass (∼ 52.1 %), with SO42−, NO3−, and NH4+ as the major ions. On average, nitrate concentrations dominated over sulfate (mass ratio of 1.21), indicating that traffic emissions were more important than stationary sources. OC and EC correlated well with each other and the highest OC ∕ EC ratio (5.16) occurred in winter, suggesting complex OC sources likely including both secondary and primary ones. Concentrations of eight trace elements (Mn, Zn, Al, B, Cr, Cu, Fe, Pb) can contribute up to ∼ 5.0 % of PM2.5 during winter. PAH concentrations were also high in winter (140.25 ng m−3), which were predominated by median/high molecular weight PAHs with five and six rings. The organic matter including both water-soluble and water-insoluble species occupied ∼ 21.5 % of the PM2.5 mass. SP-AMS determined that the WSOA had average atomic oxygen-to-carbon (O ∕ C), hydrogen-to-carbon (H ∕ C), nitrogen-to-carbon (N ∕ C), and organic matter-to-organic carbon (OM ∕ OC) ratios of 0.54, 1.69, 0.11, and 1.99, respectively. Source apportionment of WSOA further identified two secondary OA (SOA) factors (a less oxidized and a more oxidized oxygenated OA) and two primary OA (POA) factors (a nitrogen-enriched hydrocarbon-like traffic OA and a local primary OA likely including species from cooking, coal combustion, etc.). On average, the POA contribution outweighed SOA (55 % vs. 45 %), indicating the important role of local anthropogenic emissions in the aerosol pollution in Changzhou. Our measurement also shows the abundance of organic nitrogen species in WSOA, and the source analyses suggest these species are likely associated with traffic emissions, which warrants more investigations on PM samples from other locations.

scholarly journals Pulsed carbon export from mountains by earthquake-triggered landslides explored in a reduced-complexity model

2020 ◽  
Author(s):  
Thomas Croissant ◽  
Robert G. Hilton ◽  
Gen Li ◽  
Jamie Howarth ◽  
Jin Wang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Annual Runoff ◽  
Transport Processes ◽  
Mountain Range ◽  
Biogeochemical Processes ◽  
Organic Matter Degradation ◽  
Carbon Export ◽  
Model Framework ◽  
Mountain Ranges

Abstract. In mountain ranges, earthquakes can trigger widespread landsliding and mobilise large amounts of organic carbon by eroding soil and vegetation from hillslopes. Following a major earthquake, the landslide-mobilised organic carbon can be exported from river catchments by physical sediment transport processes, or stored within the landscape where it may be degraded by heterotrophic respiration. The competition between these physical and biogeochemical processes governs a net transfer of carbon between the atmosphere and sedimentary organic matter, yet their relative importance following a large landslide-triggering earthquake remains poorly constrained. Here, we propose a model framework to quantify the post-seismic redistribution of soil-derived organic carbon. The approach combines predictions based on empirical observations of co-seismic sediment mobilisation, with a description of the physical and biogeochemical processes involved after the earthquake. Earthquake-triggered landslide populations are generated by randomly sampling a landslide area distribution, a proportion of which is initially connected to the fluvial network. Initially disconnected landslide deposits are transported downslope and connected to rivers at a constant velocity in the post-seismic period. Disconnected landslide deposits lose organic carbon by heterotrophic oxidation, while connected deposits lose organic carbon synchronously by both oxidation and river export. The modelling approach is numerically efficient and allows us to explore a large range of parameter values that exert a control on the fate of organic carbon in the upland erosional system. We explore the role of the climatic context (in terms of mean annual runoff and runoff variability) and rates of organic matter degradation using single and multi-pool models. Our results highlight that the redistribution of organic carbon is strongly controlled by the annual runoff and the extent of landslide connection, but less so by the choice of organic matter degradation model. In the context of mountain ranges typical of the southwest Pacific region, we find that model configurations allow for more than 90 % of the landslide-mobilized carbon to be exported from mountain catchments. A simulation of earthquake cycles suggests efficient transfer of organic carbon out of a mountain range during the first decade of the post-seismic period. Pulsed erosion of organic matter by earthquake-triggered landslides therefore offers an effective process to promote carbon sequestration in sedimentary deposits over thousands of years.

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