Eutrophication of Lake 227 by Addition of Phosphate and Nitrate: the Second, Third, and Fourth Years of Enrichment, 1970, 1971, and 1972

1973 ◽  
Vol 30 (10) ◽  
pp. 1415-1440 ◽  
Author(s):  
D. W. Schindler ◽  
H. Kling ◽  
R. V. Schmidt ◽  
J. Prokopowich ◽  
V. E. Frost ◽  
...  
Keyword(s):  
Standing Crop ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Low Carbon ◽  
Particulate Carbon ◽  
Water Renewal ◽  
Anoxic Conditions ◽  
Natural Lakes ◽  
Low Concentrations ◽  
Carbon Concentrations

Lake 227, a small lake with extremely low concentrations of dissolved inorganic carbon, was fertilized with PO4 and NO3 for 4 years, beginning in 1969. The additions increased natural inputs of phosphorus and nitrogen about five times.Phytoplankton standing crop increased nearly two orders of magnitude, and the Cryptophyceae and Chrysophyceae present in natural lakes of the area were replaced by Chlorophyta and Cyanophyta. The standing crop of phytoplankton per square meter was near the maximum which could theoretically be maintained by surface light, in spite of the low carbon concentrations. Added phosphate and nitrate were rapidly removed by phytoplankton, so that concentrations in the lake remained low.Almost all of the added nutrient was retained by the lake, in spite of relatively fast water renewal times. An average of 80% of the phosphorus income of the lake was sedimented. There was no return of phosphorus from sediments in spite of anoxic conditions in the hypolimnion.Photosynthesizing plankton reduced dissolved inorganic carbon concentrations severely, causing a flux of atmospheric CO2 into the lake. From 69 to 95% of the inorganic + particulate carbon supplied to the lake was from the atmosphere. Results demonstrate that low carbon concentrations do not hinder eutrophication if phosphorus and nitrogen supplies are adequate.

Diurnal Variation of Dissolved Inorganic Carbon and its Use in Estimating Primary Production and CO2 Invasion in Lake 227

1973 ◽  
Vol 30 (10) ◽  
pp. 1501-1510 ◽  
Author(s):  
D. W. Schindler ◽  
E. J. Fee
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Community Respiration ◽  
Phytoplankton Production ◽  
Carbon Limitation ◽  
Low Carbon ◽  
Nitrogen And Phosphorus ◽  
Natural Lakes ◽  
Tracer Techniques

Standard in situ measurements of phytoplankton production and 14C bottle bioassays gave erroneous results when applied to lake 227, a eutrophic softwater lake in the Canadian Shield. Errors were found to be due to diurnal variations in the degree of carbon limitation of phytoplankton, and to invasion of CO2 from the atmosphere and hypolimnion.A method based on diurnal measurements of dissolved inorganic carbon, community respiration, and invasion of CO2, using gas chromatography, is described. Production by phytoplankton in lakes fertilized with nitrogen and phosphorus was found to be several times higher than in natural lakes of the area. Net production during summer stratification was found to equal invasion of CO2 from the atmosphere.The new technique should have application in other eutrophic low carbon lakes, where 14C tracer techniques are encumbered by serious technical complications.

Photoinhibition of Respiration in Epilithic Periphyton

1987 ◽  
Vol 44 (S1) ◽  
pp. s150-s153 ◽  
Author(s):  
R. W. Graham ◽  
M. A. Turner
Keyword(s):  
Sulfuric Acid ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Dark Respiration ◽  
Gross Photosynthesis ◽  
Dark Control ◽  
Low Concentrations ◽  
Effect Of Light

To determine whether respiration in the light was equal to respiration in the dark we examined epilithic periphyton from a lake acidified experimentally with sulfuric acid. Because of the low concentrations of dissolved inorganic carbon, we could use both 12C and 14C uptake techniques. Using the 14C technique we could correct for residual photosynthesis in samples treated with the photosynthetic inhibitor DCMU (3-(3,4-dichlorophenyl)-1,1-dsmethyiurea). DCMU did not alter rates of dark respiration. However, respiration of DCMU-treated samples in the light was less than in the dark (P < 0.01). This photoinhibition of respiration was about 40% of dark control values. If we had calculated gross photosynthesis for the specific conditions of this experiment, but assumed incorrectly that light and dark respiration were equal, we would have overestimated gross photosynthesis by about 30%. Thus, if the ratio of respiration to photosynthesis is high, researchers will have to evaluate the effect of light on respiration to better estimate gross photosynthesis. The technique we describe, of monitoring both 12C and 14C flux in DCMU-treated samples in the light, will provide an underestimate of respiration in the light.

Growth, photosynthesis, and extracellular organic release in colonized and axenic Myriophyllum spicatum

1989 ◽  
Vol 67 (12) ◽  
pp. 3429-3438 ◽  
Author(s):  
H. Godmaire ◽  
C. Nalewajko
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Myriophyllum Spicatum ◽  
Distribution Patterns ◽  
Release Rates ◽  
Lower Growth ◽  
Bicarbonate Uptake ◽  
Algal Photosynthesis ◽  
Major Nutrients ◽  
Carbon Concentrations

Growth and photosynthesis of axenic and colonized Myriophyllum were compared to test the validity of using axenic plants as controls in the quantification of extracellular organic carbon (EOC) release. Axenic plants were characterized by lower growth rates that could be attributed to the unavailability of some major nutrients other than N, P, or C and (or) micronutrients in the culture medium. Vmax, the maximum rate of bicarbonate uptake, and Pmax, the maximum light-saturated rate of photosynthesis, of nonaxenic Myriophyllum were significantly higher than those of axenic plants. These differences could be attributed to epiphytic algal photosynthesis. At subsaturating dissolved inorganic carbon concentrations (below 15 mg C ∙ L−1), both plants achieved similar rates of photosynthesis but differed in the kinetics of EOC release. In short-term incubation (2–6 h), 14C-EOC accounted for 0.2–0.4% of photosynthesis, and total EOC amounted to 1.3–3.8%. 14C-EOC consisted primarily (≥ 60%) of low molecular weight products (≤ 1500). No differences were apparent in size distribution patterns of 14C-EOC from axenic and nonaxenic Myriophyllum and at different dissolved inorganic carbon concentrations. Axenic plants generally showed lower rates of EOC release (in absolute values). On colonized Myriophyllum, the contribution of the epiphytes to the EOC release pool was found to be low (≤ 20% of 14C-EOC) and could partly explain the greater EOC release rates of nonaxenic plants. However, our results are not totally conclusive because the lower growth rate of axenic plants could also be responsible for the lower photosynthetic and EOC release rates of these plants.

scholarly journals Transient tracer distributions in the Fram Strait in 2012 and inferred anthropogenic carbon content and transport

Ocean Science ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 319-333 ◽  
Author(s):  
Tim Stöven ◽  
Toste Tanhua ◽  
Mario Hoppema ◽  
Wilken-Jon von Appen
Keyword(s):  
Surface Water ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Atlantic Water ◽  
Fram Strait ◽  
Polar Surface ◽  
Anthropogenic Carbon ◽  
Tracer Age ◽  
Transient Tracer ◽  
Carbon Concentrations

Abstract. The storage of anthropogenic carbon in the ocean's interior is an important process which modulates the increasing carbon dioxide concentrations in the atmosphere. The polar regions are expected to be net sinks for anthropogenic carbon. Transport estimates of dissolved inorganic carbon and the anthropogenic offset can thus provide information about the magnitude of the corresponding storage processes. Here we present a transient tracer, dissolved inorganic carbon (DIC) and total alkalinity (TA) data set along 78°50′ N sampled in the Fram Strait in 2012. A theory on tracer relationships is introduced, which allows for an application of the inverse-Gaussian–transit-time distribution (IG-TTD) at high latitudes and the estimation of anthropogenic carbon concentrations. Mean current velocity measurements along the same section from 2002–2010 were used to estimate the net flux of DIC and anthropogenic carbon by the boundary currents above 840 m through the Fram Strait. The new theory explains the differences between the theoretical (IG-TTD-based) tracer age relationship and the specific tracer age relationship of the field data, by saturation effects during water mass formation and/or the deliberate release experiment of SF6 in the Greenland Sea in 1996, rather than by different mixing or ventilation processes. Based on this assumption, a maximum SF6 excess of 0.5–0.8 fmol kg−1 was determined in the Fram Strait at intermediate depths (500–1600 m). The anthropogenic carbon concentrations are 50–55 µmol kg−1 in the Atlantic Water/Recirculating Atlantic Water, 40–45 µmol kg−1 in the Polar Surface Water/warm Polar Surface Water and between 10 and 35 µmol kg−1 in the deeper water layers, with lowest concentrations in the bottom layer. The net fluxes through the Fram Strait indicate a net outflow of  ∼  0.4 DIC and  ∼  0.01 PgC yr−1 anthropogenic carbon from the Arctic Ocean into the North Atlantic, albeit with high uncertainties.

scholarly journals B/Ca in coccoliths and relationship to calcification vesicle pH and dissolved inorganic carbon concentrations

2012 ◽  
Vol 80 ◽  
pp. 143-157 ◽  
Author(s):  
Heather Stoll ◽  
Gerald Langer ◽  
Nobumichi Shimizu ◽  
Kinuyo Kanamaru
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Carbon Concentrations
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