Predicting the Effect of Macrobenthos on the Sediment/Water Flux of Metals and Phosphorus

1985 ◽  
Vol 42 (1) ◽  
pp. 95-100 ◽  
Author(s):  
William M. Starkel
Keyword(s):  
Dissolved Oxygen ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Water Flux ◽  
Apparent Effect ◽  
Chironomid Larvae ◽  
Iron Manganese

The log-transformed flux rates of iron, manganese, and phosphorus in a small, softwater lake were linearly related to the biomass of Chaoborus and chironomid larvae. Flux rates were measured by measuring the change in chemical concentrations in the water overlying the sediment of undisturbed cores incubated in situ for 1–2 d. Predicted flux rates of iron and phosphorus at average pelagic densities of animals were enhanced at least twofold over predicted fluxes for diffusion alone. Macroinvertebrates had no apparent effect on flux rates of dissolved oxygen, dissolved inorganic carbon, potassium, or sodium.

Evaluation of reagentless pH modification for in situ ocean analysis: determination of dissolved inorganic carbon using mass spectrometry

2013 ◽  
Vol 27 (5) ◽  
pp. 635-642 ◽  
Author(s):  
Andres M. Cardenas-Valencia ◽  
Lori R. Adornato ◽  
Ryan J. Bell ◽  
Robert H. Byrne ◽  
R. Timothy Short
Keyword(s):  
Mass Spectrometry ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Analysis Determination

Diel behavior of stable isotopes of dissolved oxygen and dissolved inorganic carbon in rivers over a range of trophic conditions, and in a mesocosm experiment

2010 ◽  
Vol 269 (1-2) ◽  
pp. 22-32 ◽  
Author(s):  
Stephen R. Parker ◽  
Christopher H. Gammons ◽  
Simon R. Poulson ◽  
Michael D. DeGrandpre ◽  
Charmaine L. Weyer ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Dissolved Oxygen ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Mesocosm Experiment ◽  
Trophic Conditions

scholarly journals Presentation, calibration and validation of the low-order, DCESS Earth System Model (Version 1)

2008 ◽  
Vol 1 (1) ◽  
pp. 17-51 ◽  
Author(s):  
G. Shaffer ◽  
S. Malskær Olsen ◽  
J. O. Pepke Pedersen
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Oxygen ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
System Model ◽  
Earth System ◽  
Weathering Rates ◽  
Ocean Sediment ◽  
System Data

Abstract. A new, low-order Earth System Model is described, calibrated and tested against Earth system data. The model features modules for the atmosphere, ocean, ocean sediment, land biosphere and lithosphere and has been designed to simulate global change on time scales of years to millions of years. The atmosphere module considers radiation balance, meridional transport of heat and water vapor between low-mid latitude and high latitude zones, heat and gas exchange with the ocean and sea ice and snow cover. Gases considered are carbon dioxide and methane for all three carbon isotopes, nitrous oxide and oxygen. The ocean module has 100 m vertical resolution, carbonate chemistry and prescribed circulation and mixing. Ocean biogeochemical tracers are phosphate, dissolved oxygen, dissolved inorganic carbon for all three carbon isotopes and alkalinity. Biogenic production of particulate organic matter in the ocean surface layer depends on phosphate availability but with lower efficiency in the high latitude zone, as determined by model fit to ocean data. The calcite to organic carbon rain ratio depends on surface layer temperature. The semi-analytical, ocean sediment module considers calcium carbonate dissolution and oxic and anoxic organic matter remineralisation. The sediment is composed of calcite, non-calcite mineral and reactive organic matter. Sediment porosity profiles are related to sediment composition and a bioturbated layer of 0.1 m thickness is assumed. A sediment segment is ascribed to each ocean layer and segment area stems from observed ocean depth distributions. Sediment burial is calculated from sedimentation velocities at the base of the bioturbated layer. Bioturbation rates and oxic and anoxic remineralisation rates depend on organic carbon rain rates and dissolved oxygen concentrations. The land biosphere module considers leaves, wood, litter and soil. Net primary production depends on atmospheric carbon dioxide concentration and remineralization rates in the litter and soil are related to mean atmospheric temperatures. Methane production is a small fraction of the soil remineralization. The lithosphere module considers outgassing, weathering of carbonate and silicate rocks and weathering of rocks containing old organic carbon and phosphorus. Weathering rates are related to mean atmospheric temperatures. A pre-industrial, steady state calibration to Earth system data is carried out. Ocean observations of temperature, carbon 14, phosphate, dissolved oxygen, dissolved inorganic carbon and alkalinity constrain air-sea exchange and ocean circulation, mixing and biogeochemical parameters. Observed calcite and organic carbon distributions and inventories in the ocean sediment help constrain sediment module parameters. Carbon isotopic data and carbonate vs. silicate weathering fractions are used to estimate initial lithosphere outgassing and rock weathering rates. Model performance is tested by simulating atmospheric greenhouse gas increases, global warming and model tracer evolution for the period 1765 to 2000, as forced by prescribed anthropogenic greenhouse gas inputs and other anthropogenic and natural forcing. Long term, transient model behavior is studied with a set of 100 000 year simulations, forced by a slow, 5000 Gt C input of CO2 to the atmosphere, and with a 1.5 million year simulation, forced by a doubling of lithosphere CO2 outgassing.

In Situ Sensor Technology for Simultaneous Spectrophotometric Measurements of Seawater Total Dissolved Inorganic Carbon and pH

2015 ◽  
Vol 49 (7) ◽  
pp. 4441-4449 ◽  
Author(s):  
Zhaohui Aleck Wang ◽  
Frederick N. Sonnichsen ◽  
Albert M. Bradley ◽  
Katherine A. Hoering ◽  
Thomas M. Lanagan ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Sensor Technology ◽  
Total Dissolved Inorganic Carbon ◽  
In Situ Sensor

Controls on in situ oxygen and dissolved inorganic carbon dynamics in peats of a temperate fen

2012 ◽  
Vol 117 (G2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Cristian Estop-Aragonés ◽  
Klaus-Holger Knorr ◽  
Christian Blodau
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Dynamics

scholarly journals Short-term fate of phytodetritus in sediments across the Arabian Sea Oxygen Minimum Zone

2008 ◽  
Vol 5 (1) ◽  
pp. 43-53 ◽  
Author(s):  
J. H. Andersson ◽  
C. Woulds ◽  
M. Schwartz ◽  
G. L. Cowie ◽  
L. A. Levin ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Inorganic Carbon ◽  
Surface Sediments ◽  
Dissolved Inorganic Carbon ◽  
Oxygen Minimum Zone ◽  
Short Term ◽  
Minimum Zone ◽  
Algal Material ◽  
Oxygen Minimum

Abstract. The short-term fate of phytodetritus was investigated across the Pakistan margin of the Arabian Sea at water depths ranging from 140 to 1850 m, encompassing the oxygen minimum zone (~100–1100 m). Phytodetritus sedimentation events were simulated by adding ~44 mmol 13C-labelled algal material per m2 to surface sediments in retrieved cores. Cores were incubated in the dark, at in situ temperature and oxygen concentrations. Overlying waters were sampled periodically, and cores were recovered and sampled (for organisms and sediments) after durations of two and five days. The labelled carbon was subsequently traced into bacterial lipids, foraminiferan and macrofaunal biomass, and dissolved organic and inorganic pools. The majority of the label (20 to 100%) was in most cases left unprocessed in the sediment at the surface. The largest pool of processed carbon was found to be respiration (0 to 25% of added carbon), recovered as dissolved inorganic carbon. Both temperature and oxygen were found to influence the rate of respiration. Macrofaunal influence was most pronounced at the lower part of the oxygen minimum zone where it contributed 11% to the processing of phytodetritus.

scholarly journals Winter measurements of biogeochemical parameters in the Rockall Trough (2009–2012)

2013 ◽  
Vol 6 (2) ◽  
pp. 389-409
Author(s):  
T. McGrath ◽  
C. Kivimäe ◽  
E. McGovern ◽  
R. R. Cave ◽  
E. Joyce
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Dissolved Inorganic Nutrients ◽  
Chemical Signatures ◽  
Rockall Trough ◽  
Biogeochemical Parameters ◽  
Oxidised Nitrogen

Abstract. This paper describes the sampling and analysis of biogeochemical parameters collected in the Rockall Trough in January/February of 2009, 2010, 2011 and 2012. Sampling was carried out across two transects, one southern and one northern transect each year. Samples for dissolved inorganic carbon (DIC) and total alkalinity (TA) were taken alongside salinity, dissolved oxygen and dissolved inorganic nutrients (total-oxidised nitrogen, nitrite, phosphate and silicate) to describe the chemical signatures of the various water masses in the region. These were taken at regular intervals through the water column. The 2009 and 2010 data are available on the CDIAC database.

The responses of phytoplankton communities to elevated CO2 show seasonal variations in the highly eutrophic Lake Taihu

2016 ◽  
Vol 73 (5) ◽  
pp. 727-736 ◽  
Author(s):  
Xiaoli Shi ◽  
Xuhui Zhao ◽  
Min Zhang ◽  
Zhou Yang ◽  
Ping Xu ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Net Primary Production ◽  
Lake Taihu ◽  
High Growth ◽  
Eutrophic Lake ◽  
High Growth Rate ◽  
Four Seasons ◽  
Phytoplankton Communities

From April 2012 to January 2013 (over four seasons), in situ microcosm experiments were conducted in Lake Taihu, perturbed over a range of pCO2 scenarios (270, 380, and 750 μatm; 1 atm = 101.325 kPa). The influence of CO2 level on microcosms was greatest during the spring because of the high growth rate of phytoplankton. In this season, rising CO2 levels caused a pH reduction, and the maximum reduction was 0.6 units when CO2 level was enhanced from the present level to 750 μatm. The doubling of CO2 level could increase the net primary production (NPP) by 65% during spring when the concentrations of other nutrients were maintained. The rise of NPP could cause a decline of dissolved inorganic carbon (DIC) concentration, and CO2 enrichment might mitigate the extent of this decline. Meanwhile, higher CO2 may slow or prevent a loss of diversity of phytoplankton in microcosms in this season. During the other three seasons, Microcystis predominated, and the percentage of cyanobacteria did not alter with the change of CO2. We did not observe a significant increase in the abundance of any taxa with the rise of CO2 during the in situ microcosm experiments.

Sign in / Sign up

Export Citation Format

Share Document