scholarly journals Multidecadal change in the dissolved inorganic carbon in a long-term ocean state estimation

2015 ◽  
Vol 7 (4) ◽  
pp. 1885-1900 ◽  
Author(s):  
Toshimasa Doi ◽  
Satoshi Osafune ◽  
Nozomi Sugiura ◽  
Shinya Kouketsu ◽  
Akihiko Murata ◽  
...  
Keyword(s):  
State Estimation ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Ocean State Estimation

Variations in the Isotopic Composition of Dissolved Inorganic Carbon in the Unsaturated Zone of a Semi-Arid Region

Radiocarbon ◽  
2015 ◽  
Vol 57 (3) ◽  
pp. 397-406 ◽  
Author(s):  
I Carmi ◽  
D Yakir ◽  
Y Yechieli ◽  
J Kronfield ◽  
M Stiller
Keyword(s):  
Unsaturated Zone ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Sediment Cores ◽  
Tritium Content ◽  
Organic Debris ◽  
Different Seasons ◽  
Semi Arid Region ◽  
Semi Arid

A study of water and carbon isotopes was conducted in a bare plot in the unsaturated zone of the Yatir Forest in the northern Negev of Israel. Sediment cores were collected in three different seasons. Measurements include profiles of mineralogy, moisture and its δ18O and tritium content, dissolved inorganic carbon (DIC) and its δ13C (‰) and Δ14C (‰) content, and δ13C (‰) and Δ14C (‰) in the solid sediment. The profiles of moisture and δ18O in the cores show clearly the effect of evaporation. The tritium profile indicates infiltration of water (0.11 m yr−1). The source of carbon in the DIC is CO2 released by biotic activity through roots of trees and of seasonal plants, which show seasonal variations, and by decay of organic debris. The δ13C (‰) profiles show clearly the chemical transition from dissolved CO2 (δ13C = −22‰) to bicarbonate (δ13C = −14‰). At greater depth (–11.3‰), the δ13C becomes similar to the δ13C in the aquifer below (–12.5‰). The effect of secondary processes is evident in the profile of Δ14C in the DIC. It shows a clear decrease with depth due to exchange with the sediment at a rate of 10‰ yr−1. Precipitation of carbon from the DIC on the sediment is 1.1 mg C Lsed−1 yr−1, negligible compared to the 28 g C in 1 Lsed. In the solid sediment, there is a gradient in Δ14Ccarb at the top meter. The net precipitation of 14C from the DIC on the sediment (0.25 to 1.1‰ yr−1), corrected for decay, cannot be observed in the deeper sediment. The presence of 14C in the top 1 m of the sediment is explained by two possible processes: accumulation of 14C-tagged dust (∼0.05 mm yr−1) and/or long-term cumulative precipitation from the DIC.

scholarly journals Vanishing coccolith vital effects with alleviated CO<sub>2</sub> limitation

2015 ◽  
Vol 12 (18) ◽  
pp. 15835-15866 ◽  
Author(s):  
M. Hermoso ◽  
I. Z. X. Chan ◽  
H. L. O. McClelland ◽  
A. M. C. Heureux ◽  
R. E. M. Rickaby
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Calcareous Nannofossils ◽  
Carbon And Oxygen Isotopes ◽  
Carbon Availability ◽  
Vital Effect ◽  
Vital Effects ◽  
Multiple Species ◽  
Atmospheric Co2 Concentrations

Abstract. By recreating a range of geologically relevant concentrations of dissolved inorganic carbon (DIC) in the laboratory, we demonstrate that the magnitude of the vital effects in both carbon and oxygen isotopes of coccolith calcite of multiple species relates to ambient DIC concentration. Under high DIC levels, all the examined coccoliths lacked any offset from inorganic calcite, whereas in low (present-day) DIC concentrations, these vital effects and interspecies differences become substantial. These laboratory observations support the recent hypothesis from field observations that the appearance of interspecific vital effect in coccolithophores coincides with the long-term Neogene decline of atmospheric CO2 concentrations. The present study brings further valuable constraints on coccolith isotopic compositions by demonstrating the threshold for the absence of vital effects under high DIC regimes. From a mechanistic viewpoint, we show that the vital effect is determined by physiology; growth rate, cell size and relative rates of photosynthesis and calcification, and a modulation of these parameters with ambient carbon availability. This study provides palaeoceanographers with a biogeochemical framework that can be utilised to further develop the use of calcareous nannofossils in palaeoceanography to derive sea surface temperature and pCO2 levels.

scholarly journals Fluxes of carbon and nutrients to the Iceland Sea surface layer and inferred primary productivity and stoichiometry

2015 ◽  
Vol 12 (3) ◽  
pp. 875-885 ◽  
Author(s):  
E. Jeansson ◽  
R. G. J. Bellerby ◽  
I. Skjelvan ◽  
H. Frigstad ◽  
S. R. Ólafsdóttir ◽  
...  
Keyword(s):  
Surface Layer ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Vertical Mixing ◽  
Sea Surface ◽  
Net Community Production ◽  
Horizontal Advection ◽  
Vertical Fluxes ◽  
Community Production

Abstract. This study evaluates long-term mean fluxes of carbon and nutrients to the upper 100 m of the Iceland Sea. The study utilises hydro-chemical data from the Iceland Sea time series station (68.00° N, 12.67° W), for the years between 1993 and 2006. By comparing data of dissolved inorganic carbon (DIC) and nutrients in the surface layer (upper 100 m), and a sub-surface layer (100–200 m), we calculate monthly deficits in the surface, and use these to deduce the long-term mean surface layer fluxes that affect the deficits: vertical mixing, horizontal advection, air–sea exchange, and biological activity. The deficits show a clear seasonality with a minimum in winter, when the mixed layer is at the deepest, and a maximum in early autumn, when biological uptake has removed much of the nutrients. The annual vertical fluxes of DIC and nitrate amounts to 2.9 ± 0.5 and 0.45 ± 0.09 mol m−2 yr−1, respectively, and the annual air–sea uptake of atmospheric CO2 is 4.4 ± 1.1 mol C m−2 yr−1. The biologically driven changes in DIC during the year relates to net community production (NCP), and the net annual NCP corresponds to export production, and is here calculated as 7.3 ± 1.0 mol C m−2 yr−1. The typical, median C : N ratio during the period of net community uptake is 9.0, and clearly higher than the Redfield ratio, but is varying during the season.

scholarly journals Long-term hydrolytically stable bond formation for future membrane-based deep ocean microfluidic chemical sensors

Lab on a Chip ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1287-1295 ◽  
Author(s):  
M. Tweedie ◽  
D. Sun ◽  
B. Ward ◽  
P. D. Maguire
Keyword(s):  
Chemical Analysis ◽  
Chemical Sensors ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Bond Formation ◽  
Deep Ocean ◽  
Two Fluid

Future ocean profiling of dissolved inorganic carbon and other analytes will require miniaturised chemical analysis systems based on sealed gas membranes between two fluid channels.

scholarly journals Δ14C and Δ13C of Seawater DIC as Tracers of Coastal Upwelling: A 5-Year Time Series from Southern California

Radiocarbon ◽  
2011 ◽  
Vol 53 (4) ◽  
pp. 669-677 ◽  
Author(s):  
Guaciara M Santos ◽  
Julie Ferguson ◽  
Karla Acaylar ◽  
Kathleen R Johnson ◽  
Sheila Griffin ◽  
...  
Keyword(s):  
Time Series ◽  
Ocean Circulation ◽  
Southern California ◽  
Inorganic Carbon ◽  
Coastal Upwelling ◽  
Dissolved Inorganic Carbon ◽  
Southern California Bight ◽  
Surface Seawater ◽  
Upwelling Event

Marine radiocarbon (14C) is a widely used tracer of past ocean circulation, but very few high-resolution records have been obtained. Here, we report a time series of carbon isotope abundances of dissolved inorganic carbon (DIC) in surface seawater collected from the Newport Beach pier in Orange County, within the Southern California Bight, from 2005 to 2010. Surface seawater was collected bimonthly and analyzed for Δ14C, δ13C, and salinity. Results from May 2005 to November 2010 show no long-term changes in δ13C DIC values and no consistent variability that can be attributed to upwelling. Δ14C DIC values have lowered from ∼34‰ to about ∼16‰, an 18‰ decrease from the beginning of this project in 2005, and is consistent with the overall 14C depletion from the atmospheric thermonuclear bomb pulse at the end of the 1950s. Δ14C DIC values, paired with salinity, do appear to be suitable indicators of upwelling strength with periods of upwelling characterized by more saline and lower DIC Δ14C values. However, a similar signal was not observed during the strong upwelling event of 2010. These results were obtained in the Southern California Bight where upwelling is fairly weak and there is a complex occanographic circulation in comparison with the remaining western USA coastline. It is therefore likely that the link between DIC Δ14C, salinity, and upwelling would be even stronger at other sites. These data represent the longest time series of Δ14C data from a coastal Southern California site performed to date.

scholarly journals Coral calcification mechanisms facilitate adaptive responses to ocean acidification

2017 ◽  
Vol 284 (1868) ◽  
pp. 20172117 ◽  
Author(s):  
Verena Schoepf ◽  
Christopher P. Jury ◽  
Robert J. Toonen ◽  
Malcolm T. McCulloch
Keyword(s):  
Ocean Acidification ◽  
Inorganic Carbon ◽  
Coral Species ◽  
Dissolved Inorganic Carbon ◽  
Adaptive Responses ◽  
Natural Gradient ◽  
Coral Calcification ◽  
Seawater Ph ◽  
Two Temperatures

Ocean acidification (OA) is a pressing threat to reef-building corals, but it remains poorly understood how coral calcification is inhibited by OA and whether corals could acclimatize and/or adapt to OA. Using a novel geochemical approach, we reconstructed the carbonate chemistry of the calcifying fluid in two coral species using both a pH and dissolved inorganic carbon (DIC) proxy (δ 11 B and B/Ca, respectively). To address the potential for adaptive responses, both species were collected from two sites spanning a natural gradient in seawater pH and temperature, and then subjected to three pH T levels (8.04, 7.88, 7.71) crossed by two temperatures (control, +1.5°C) for 14 weeks. Corals from the site with naturally lower seawater pH calcified faster and maintained growth better under simulated OA than corals from the higher-pH site. This ability was consistently linked to higher pH yet lower DIC values in the calcifying fluid, suggesting that these differences are the result of long-term acclimatization and/or local adaptation to naturally lower seawater pH. Nevertheless, all corals elevated both pH and DIC significantly over seawater values, even under OA. This implies that high pH upregulation combined with moderate levels of DIC upregulation promote resistance and adaptive responses of coral calcification to OA.

U.S. GODAE: Sustained Global Ocean State Estimation for Scientific and Practical Application

2004 ◽  
Author(s):  
Carl Wunsch ◽  
Ichiro Fukumori ◽  
Tong Lee ◽  
Dimitris Menemenlis ◽  
David W. Behringer ◽  
...  
Keyword(s):  
State Estimation ◽  
Global Ocean ◽  
Practical Application ◽  
Ocean State Estimation
Sign in / Sign up

Export Citation Format

Share Document