scholarly journals Carbon limitation of lake productivity

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181415 ◽  
Author(s):  
Theis Kragh ◽  
Kaj Sand-Jensen
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Light Availability ◽  
Hard Water ◽  
Carbon Limitation ◽  
Lake Productivity ◽  
Phytoplankton Productivity ◽  
Lake Ecosystems ◽  
Oxygen Conditions ◽  
Mesocosm Experiments ◽  
Flow Through

Phytoplankton productivity in lakes controls the rate of synthesis of organic matter that drives energy flow through the food webs and regulates the transparency and oxygen conditions in the water. Limitation of phytoplankton productivity and biomass by nutrients and light availability is an established paradigm for lake ecosystems, whereas invasion of atmospheric CO 2 has been assumed to cover the high demands of dissolved inorganic carbon (DIC) during intense organic productivity. We challenge this paradigm, and show up to a 5-fold stimulation of phytoplankton productivity and biomass in outdoor mesocosms enriched with DIC, compared to mesocosms with lower DIC concentrations. High DIC supported phytoplankton productivity by direct algal uptake of bicarbonate, through the release of CO 2 coupled to calcification and by inducing high pH that greatly enhances atmospheric CO 2 invasion. Comparisons of 204 natural Danish lakes supported mesocosm experiments showing higher phytoplankton biomass and pH levels in hard water than soft water lakes for the same nutrient and light availabilities. The most productive lakes are nutrient-rich, hard water lakes that attain surface pHs of 10–11 and chemically enhance atmospheric CO 2 uptake 10–15-fold. Our results will help understand natural variations of lake productivity along gradients in nutrients, DIC and pH.

Carbon Isotope Composition of Lake Sediments in Relation to Lake Productivity and Radiocarbon Dating

1992 ◽  
Vol 37 (3) ◽  
pp. 333-345 ◽  
Author(s):  
Ramon Aravena ◽  
Barry G. Warner ◽  
Glen M. MacDonald ◽  
Karen I. Hanf
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Lake Water ◽  
Dissolved Inorganic Carbon ◽  
Isotope Composition ◽  
Hard Water ◽  
Lake Basin ◽  
Lake Productivity ◽  
Radiocarbon Dates ◽  
Organic Sediment

AbstractCarbon-13 profiles and radiocarbon dates were obtained from two Canadian kettle basins having similar geological and hydrological characteristics to develop criteria for evaluating the validity of radiocarbon dates on lake sediment from basins in calcareous terrain. Radiocarbon dates from a site in Alberta show a variable hard-water effect related to local hydrological changes during postglacial history of the lake basin, whereas radiocarbon dates from the other site in Ontario show no noticeable influence of old carbon during its history. These differences are mainly related to lake water residence time, which has influenced carbon isotopic exchange between atmospheric CO2 and dissolved inorganic carbon in lake water. δ13C values for bulk organic sediment and terrestrial and aquatic macrofossils reveal that the main component of lake sediment at both sites is autocthonous in origin. Furthermore, each site supported different submerged aquatic plant communities that used different sources of carbon for photosynthesis, thereby imprinting the organic sediments with a characteristic 13C composition. Both sites reflect a clear relationship between 13C values and paleoproductivity. This study shows the individualistic response of the developing lake system to the hydrology, lake biota, and local geology, and demonstrates the problem of using 13C in lake sediments as a single criterion to recognize the validity of radiocarbon dates of lake sediment without supporting paleoecological information.

Factors influencing the growth of Mougeotia in experimentally acidified mesocosms

2000 ◽  
Vol 57 (3) ◽  
pp. 538-547 ◽  
Author(s):  
Jennifer L Klug ◽  
Janet M Fischer
Keyword(s):  
Inorganic Carbon ◽  
Phytoplankton Community ◽  
Dissolved Inorganic Carbon ◽  
Abiotic Factors ◽  
Minor Role ◽  
Little Rock ◽  
Factors Associated ◽  
Phytoplankton Communities ◽  
Mesocosm Experiments ◽  
Potential Factors

Acidification causes profound changes in species composition in aquatic systems. We conducted mesocosm experiments in three northern Wisconsin lakes (Trout Lake, Little Rock - Reference, Little Rock - Treatment) to test how different phytoplankton communities respond to acidification. Major differences exist among these lakes in water chemistry and phytoplankton community composition. In each lake, three pH treatments (control, press (sustained pH 4.7), and pulse (alternating pH 4.7 and ambient pH)) were maintained for 6 weeks. We observed a striking increase in species in the genus Mougeotia in all systems. Mougeotia is a filamentous green alga often found in acidified lakes. The magnitude of the Mougeotia increase differed among lakes and treatments, and we used an autoregressive model to identify potential factors responsible for these differences. Our results suggest that biotic factors such as competition with other algae played a relatively minor role in regulating Mougeotia dynamics. Instead, pH and abiotic factors associated with changes in pH (e.g., dissolved inorganic carbon) were important predictors of Mougeotia dynamics.

scholarly journals Vanishing coccolith vital effects with alleviated carbon limitation

2016 ◽  
Vol 13 (1) ◽  
pp. 301-312 ◽  
Author(s):  
M. Hermoso ◽  
I. Z. X. Chan ◽  
H. L. O. McClelland ◽  
A. M. C. Heureux ◽  
R. E. M. Rickaby
Keyword(s):  
Dissolved Inorganic Carbon ◽  
High Pco2 ◽  
Carbon Limitation ◽  
Primary Control ◽  
Calcareous Nannofossils ◽  
Carbon And Oxygen Isotopes ◽  
Interspecific Differences ◽  
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 exhibit significantly reduced isotopic offsets from inorganic calcite compared to the substantial vital effects expressed at low (preindustrial and present-day) DIC concentrations. The supply of carbon to the cell exerts a primary control on biological fractionation in coccolith calcite via the modulation of coccolithophore growth rate, cell size and carbon utilisation by photosynthesis and calcification, altogether accounting for the observed interspecific differences between coccolith species. 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 and bring further valuable constraints by demonstrating a convergence of all examined species towards inorganic values at high pCO2 regimes. 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, especially during periods of relatively elevated pCO2 concentrations, as they prevailed during most of the Meso-Cenozoic.

scholarly journals CO2 Uptake and Fixation by Endosymbiotic Chemoautotrophs from the Bivalve Solemya velum

2006 ◽  
Vol 73 (4) ◽  
pp. 1174-1179 ◽  
Author(s):  
Kathleen M. Scott ◽  
Colleen M. Cavanaugh
Keyword(s):  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Dissolved Inorganic Carbon ◽  
Co2 Uptake ◽  
Maximal Velocity ◽  
Marine Habitats ◽  
Half Saturation Constant ◽  
Oxygen Conditions ◽  
Solemya Velum ◽  
Influence Of Ph

ABSTRACT Chemoautotrophic symbioses, in which endosymbiotic bacteria are the major source of organic carbon for the host, are found in marine habitats where sulfide and oxygen coexist. The purpose of this study was to determine the influence of pH, alternate sulfur sources, and electron acceptors on carbon fixation and to investigate which form(s) of inorganic carbon is taken up and fixed by the gamma-proteobacterial endosymbionts of the protobranch bivalve Solemya velum. Symbiont-enriched suspensions were generated by homogenization of S. velum gills, followed by velocity centrifugation to pellet the symbiont cells. Carbon fixation was measured by incubating the cells with 14C-labeled dissolved inorganic carbon. When oxygen was present, both sulfide and thiosulfate stimulated carbon fixation; however, elevated levels of either sulfide (>0.5 mM) or oxygen (1 mM) were inhibitory. In the absence of oxygen, nitrate did not enhance carbon fixation rates when sulfide was present. Symbionts fixed carbon most rapidly between pH 7.5 and 8.5. Under optimal pH, sulfide, and oxygen conditions, symbiont carbon fixation rates correlated with the concentrations of extracellular CO2 and not with HCO3 − concentrations. The half-saturation constant for carbon fixation with respect to extracellular dissolved CO2 was 28 � 3 μM, and the average maximal velocity was 50.8 � 7.1 μmol min−1 g of protein−1. The reliance of S. velum symbionts on extracellular CO2 is consistent with their intracellular lifestyle, since HCO3 − utilization would require protein-mediated transport across the bacteriocyte membrane, perisymbiont vacuole membrane, and symbiont outer and inner membranes. The use of CO2 may be a general trait shared with many symbioses with an intracellular chemoautotrophic partner.

scholarly journals The impact on atmospheric CO<sub>2</sub> of iron fertilization induced changes in the ocean's biological pump

2007 ◽  
Vol 4 (5) ◽  
pp. 3863-3911 ◽  
Author(s):  
X. Jin ◽  
N. Gruber ◽  
H. Frenzel ◽  
S. C. Doney ◽  
J. C. McWilliams
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Light Availability ◽  
Co2 Flux ◽  
Surface Patch ◽  
Biological Pump ◽  
Small Surface ◽  
Uptake Efficiency ◽  
Iron Fertilization ◽  
Basin Scale ◽  
The Impact

Abstract. Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical biogeochemical ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC) removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability) tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

scholarly journals Sentinel-2 for mapping the spatio-temporal development of submerged aquatic vegetation at Lake Starnberg (Germany)

2019 ◽  
Vol 78 (1) ◽  
Author(s):  
Christine Fritz ◽  
Katja Kuhwald ◽  
Thomas Schneider ◽  
Juergen Geist ◽  
Natascha Oppelt
Keyword(s):  
Trophic State ◽  
Submerged Aquatic Vegetation ◽  
Aquatic Vegetation ◽  
Environmental Changes ◽  
Light Availability ◽  
Empirical Method ◽  
Lake Ecosystems ◽  
In Situ Data ◽  
Spatio Temporal ◽  
Sentinel 2

Submerged aquatic vegetation (SAV) plays an important role in freshwater lake ecosystems. Due to its sensitivity to environmental changes, several SAV species serve as bioindicators for the trophic state of freshwater lakes. Variations in water temperature, light availability and nutrient concentration affect SAV growth and species composition. To monitor the trophic state as required by the European Water Framework Directive (WFD), SAV needs to be monitored regularly. This study analyses the development of macrophyte patches at Lake Starnberg, Germany, by exploring four Sentinel-2A acquired within the main growing season in August and September 2015. Two different methods of littoral bottom coverage assessment are compared, i.e. a semi-empirical method using depth-invariant indices and a physically based, bio-optical method using WASI-2D (Water Colour Simulator). For a precise Sentinel-2 imaging by date and hour, satellite measurements were supported by lake bottom spectra delivered by in situ data based reflectance models. Both methods identified vegetated and non-vegetated patches in shallow water areas. Furthermore, tall- and meadow-growing SAV growth classes could be differentiated. Both methods revealed similar results when focusing on the identification of sediment and SAV patches (R² from 0.56 to 0.81), but not for a differentiation on SAV class growth level (R² <0.42).

Temperature Rising (Two Celsius) Effect on Planktonic Biomass in Subtropical Marshes, Iraq

2021 ◽  
Vol 5 (1) ◽  
pp. 44-52
Author(s):  
Mohammed Al-Haidarey
Keyword(s):  
Climate Change ◽  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Winter Season ◽  
Heating System ◽  
Early Spring ◽  
Natural Sediment ◽  
Lake Ecosystems

Planktonic species may respond to climate change through their niche across three axes which include self, space and time. This study was designed to investigate the effect of increasing winter temperature on the plankton biomass, the mesocosm was constructed as a collection of 16 enclosures with a water-outlet system and natural sediment, two aquatic plant species and heating system. This research was conducted over 12 weeks (beginning on Dec. 2018) when the temperature of eight enclosures was 2±0.2 °C higher than the ambient temperature. Weekly abiotic parameters (salinity, pH, PO4, NO3, DIC) and biotic (chlorophyll-a, zooplankton and phytoplankton biomass) were reported. The obtained results showed that there were no major improvements in salinity, pH, PO4, NO3 and dissolved inorganic carbon (DIC). Whereas, chlorophyll-a, zooplankton and phytoplankton biomass have dramatically improved. Therefore, this research has indicated that water temperature change during the winter season due to climate change could affect planktonic biomass and early spring in subtropical marshes, but this study was performed in the mesocosm experiment and it needs to be studied in large-scale natural lake ecosystems.

scholarly journals Periphyton Function in Lake Ecosystems

2002 ◽  
Vol 2 ◽  
pp. 1449-1468 ◽  
Author(s):  
Yvonne Vadeboncoeur ◽  
Alan D. Steinman
Keyword(s):  
Light Availability ◽  
Habitat Type ◽  
High Water ◽  
Nutrient Cycles ◽  
Lake Morphometry ◽  
Trophic Conditions ◽  
Lake Ecosystems ◽  
Food Web Interactions ◽  
Spatial Hierarchy

Periphyton communities have received relatively little attention in lake ecosystems. However, evidence is increasing that they play a key role in primary productivity, nutrient cycling, and food web interactions. This review summarizes those findings and places them in a conceptual framework to evaluate the functional importance of periphyton in lakes. The role of periphyton is conceptualized based on a spatial hierarchy. At the coarsest scale, landscape properties such as lake morphometry, influence the amount of available habitat for periphyton growth. Watershed-related properties, such as loading of dissolved organic matter, nutrients, and sediments influence light availability and hence periphyton productivity. At the finer scale of within the lake, both habitat availability and habitat type affect periphyton growth and abundance. In addition, periphyton and phytoplankton compete for available resources at the within-lake scale. Our review indicates that periphyton plays an important functional role in lake nutrient cycles and food webs, especially under such conditions as relatively shallow depths, nutrient-poor conditions, or high water-column transparency. We recommend more studies assessing periphyton function across a spectrum of lake morphometry and trophic conditions.

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