Differences in organic carbon release between conchocelis and thalli of Pyropia haitanensis and responses to changes in light intensity and pH

2022 ◽  
Vol 61 ◽  
pp. 102574
Author(s):  
Kai Xu ◽  
Mengya Li ◽  
Wenlei Wang ◽  
Yan Xu ◽  
Dehua Ji ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Light Intensity ◽  
Pyropia Haitanensis ◽  
Carbon Release

scholarly journals Benthic organic carbon release stimulates bacterioplankton production in a clear-water subarctic lake

2013 ◽  
Vol 32 (1) ◽  
pp. 176-182 ◽  
Author(s):  
Patricia Rodríguez ◽  
Jenny Ask ◽  
Catherine L Hein ◽  
Mats Jansson ◽  
Jan Karlsson
Keyword(s):  
Organic Carbon ◽  
Clear Water ◽  
Bacterioplankton Production ◽  
Carbon Release ◽  
Subarctic Lake

scholarly journals Dissolved and Particulate Organic Carbon in Icelandic Proglacial Streams: A First Estimate

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 748 ◽  
Author(s):  
Peter Chifflard ◽  
Christina Fasching ◽  
Martin Reiss ◽  
Lukas Ditzel ◽  
Kyle S. Boodoo
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Ice Cap ◽  
Glacier Terminus ◽  
Fluorescence Measurements ◽  
Sampling Locations ◽  
Carbon Release ◽  
Annual Carbon ◽  
Spatio Temporal

Here for the first time, we analyze the concentration of dissolved (DOC) and particulate organic carbon (POC), as well as its optical properties (absorbance and fluorescence) from several proglacial streams across Iceland, the location of Europe’s largest non-polar ice cap. We found high spatial variability of DOC concentrations and dissolved organic matter (DOM) composition during peak melt, sampling 13 proglacial streams draining the 5 main Icelandic glaciers. Although glacial-derived organic matter (OM) was dominated by proteinaceous florescence, organic matter composition was variable among glaciers, often exhibiting relatively higher aromatic content and increased humification (based on absorbance and fluorescence measurements) closer to the glacier terminus, modulated by the presence of glacial lakes. Additional sampling locations the in flow path of the river Hvitá revealed that while POC concentrations decreased downstream, DOC concentrations and the autochthonous fraction of OM increased, suggesting the reworking of the organic carbon by microbial communities, with likely implications for downstream ecosystems as glaciers continue to melt. Based on our measured DOC concentrations ranging from 0.11 mg·L−1 to 0.94 mg·L−1, we estimate a potential annual carbon release of 0.008 ± 0.002 Tg·C·yr−1 from Icelandic glaciers. This non-conservative first estimate serves to highlight the potentially significant contribution of Icelandic pro-glacial streams to the global carbon cycle and the need for the quantification and determination of the spatio-temporal variation of DOC and POC fluxes and their respective drivers, particularly in light of increased rates of melting due to recent trends in climatic warming.

scholarly journals Light Modulates the Physiology of NonphototrophicActinobacteria

2019 ◽  
Vol 201 (10) ◽  
Author(s):  
Julia A. Maresca ◽  
Jessica L. Keffer ◽  
Priscilla P. Hempel ◽  
Shawn W. Polson ◽  
Olga Shevchenko ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Cellular Response ◽  
Action Spectrum ◽  
Sugar Transport ◽  
Growth Effect ◽  
Carbon Uptake ◽  
Aquatic Environments ◽  
Primary Producers ◽  
Carbon And Nitrogen ◽  
Carbon Release

ABSTRACTLight is a source of energy and an environmental cue that is available in excess in most surface environments. In prokaryotic systems, conversion of light to energy by photoautotrophs and photoheterotrophs is well understood, but the conversion of light to information and the cellular response to that information have been characterized in only a few species. Our goal was to explore the response of freshwaterActinobacteria, which are ubiquitous in illuminated aquatic environments, to light. We found thatActinobacteriawithout functional photosystems grow faster in the light, likely because sugar transport and metabolism are upregulated in the light. Based on the action spectrum of the growth effect and comparisons of the genomes of threeActinobacteriawith this growth rate phenotype, we propose that the photosensor in these strains is a putative CryB-type cryptochrome. The ability to sense light and upregulate carbohydrate transport during the day could allow these cells to coordinate their time of maximum organic carbon uptake with the time of maximum organic carbon release by primary producers.IMPORTANCESunlight provides information about both place and time. In sunlit aquatic environments, primary producers release organic carbon and nitrogen along with other growth factors during the day. The ability ofActinobacteriato coordinate organic carbon uptake and utilization with production of photosynthate enables them to grow more efficiently in the daytime, and it potentially gives them a competitive advantage over heterotrophs that constitutively produce carbohydrate transporters, which is energetically costly, or produce transporters only after detection of the substrate(s), which delays their response. Understanding how light cues the transport of organic carbon and its conversion to biomass is key to understanding biochemical mechanisms within the carbon cycle, the fluxes through it, and the variety of mechanisms by which light enhances growth.

scholarly journals Reduced carbon cycle resilience across the Palaeocene–Eocene Thermal Maximum

2018 ◽  
Vol 14 (10) ◽  
pp. 1515-1527 ◽  
Author(s):  
David I. Armstrong McKay ◽  
Timothy M. Lenton
Keyword(s):  
Organic Carbon ◽  
Carbon Cycle ◽  
Deep Ocean ◽  
Tipping Point ◽  
Tipping Points ◽  
Carbon Burial ◽  
Thermal Maximum ◽  
Organic Carbon Burial ◽  
Carbon Release ◽  
Hyperthermal Events

Abstract. Several past episodes of rapid carbon cycle and climate change are hypothesised to be the result of the Earth system reaching a tipping point beyond which an abrupt transition to a new state occurs. At the Palaeocene–Eocene Thermal Maximum (PETM) at ∼56 Ma and at subsequent hyperthermal events, hypothesised tipping points involve the abrupt transfer of carbon from surface reservoirs to the atmosphere. Theory suggests that tipping points in complex dynamical systems should be preceded by critical slowing down of their dynamics, including increasing temporal autocorrelation and variability. However, reliably detecting these indicators in palaeorecords is challenging, with issues of data quality, false positives, and parameter selection potentially affecting reliability. Here we show that in a sufficiently long, high-resolution palaeorecord there is consistent evidence of destabilisation of the carbon cycle in the ∼1.5 Myr prior to the PETM, elevated carbon cycle and climate instability following both the PETM and Eocene Thermal Maximum 2 (ETM2), and different drivers of carbon cycle dynamics preceding the PETM and ETM2 events. Our results indicate a loss of “resilience” (weakened stabilising negative feedbacks and greater sensitivity to small shocks) in the carbon cycle before the PETM and in the carbon–climate system following it. This pre-PETM carbon cycle destabilisation may reflect gradual forcing by the contemporaneous North Atlantic Volcanic Province eruptions, with volcanism-driven warming potentially weakening the organic carbon burial feedback. Our results are consistent with but cannot prove the existence of a tipping point for abrupt carbon release, e.g. from methane hydrate or terrestrial organic carbon reservoirs, whereas we find no support for a tipping point in deep ocean temperature.

scholarly journals The effect of water conditions on the phenology and age structure of Luronium natans (L.) Raf. populations

2011 ◽  
Vol 74 (3) ◽  
pp. 253-262 ◽  
Author(s):  
Ewa Bazydło ◽  
Józef Szmeja
Keyword(s):  
Organic Carbon ◽  
Light Intensity ◽  
Total Nitrogen ◽  
Flowering Period ◽  
Development Stages ◽  
Water Conditions ◽  
Nitrogen Concentrations ◽  
Generative Phase ◽  
North Western ◽  
Do So

The study presents the results of the analysis of development stages of <em>Luronium natans</em> (L.) Raf. depending on water conditions (pH, light, total nitrogen, total phosphorus, organic carbon) in 21 populations in north-western Poland. The fractions of seedlings, juvenile, mature and generative stems, as well as the course of phenological phenomena were determined. Seedlings are sparse and can be found from May to July. Most of them occur in waters ranging from slightly acid to neutral (pH 6.0-7.0) with TP concentrations of 10-20 µg dm<sup>-3</sup>, TN concentrations &lt; 1.0 mg dm<sup>-3</sup> and DOC concentrations of 3.5-5.0 mg dm<sup>-3</sup>, on a mineral (5-10% OC) and fairly well lit (31-40% PAR) substrate. The generative phase lasts from May to October. The flowering period is between August and mid-September. Only 35.2±9.4% of flowering stems produce fruits. The plant flowers abundantly in waters with total nitrogen concentrations &gt; 1.2 mg dm<sup>-3</sup>, that is above the level of TN concentrations most favourable to seedlings and both juvenile and mature individuals. TP and DOC concentrations, and light intensity (PAR) do not influence the size of the generative stems fraction in populations. However, sediment structure is of importance in this respect: about 62.9% of stems flower and fruit on a mineral substrate (&lt; 1% OC), whereas only 17.4% do so on an organic one. The results of this study may be useful in the conservation of this endangered European endemic species.

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