Production and respiration in the Red Sea coral Stylophora pistillata as a function of depth

1984 ◽  
Vol 222 (1227) ◽  
pp. 215-230 ◽  
Keyword(s):  
Carbon Fixation ◽  
Algal Cell ◽  
Unit Surface Area ◽  
Fixed Carbon ◽  
Host Animal ◽  
Direct Function ◽  
Stylophora Pistillata ◽  
Carbon Availability ◽  
Branch Density ◽  
Average Size

Colony morphology, rates of production and respiration, translocation of carbon from symbiotic algae to host, and the daily contribution of carbon fixed by zooxanthellae to animal respiration demands (CZAR) in phenotypes of Stylophora pistillata from 3 and 35 m were compared. Corals from 35 m showed an increase in branch density, a decrease in zooxanthellae density, and an increase in chlorophyll a per algal cell when compared to colonies from 3m. These changes are explained as adaptations to limited photosynthetically active radiation at the deeper depth. Photosynthetic efficiency was higher at 35 m, as evidenced by a production rate 25% that at 3 m, but with light only about 8% that of shallow water irradiance. Respiration of deeper corals decreased by a half. A depth-specific respiratory decline was displayed by both the algae and the animal fractions. Decreased coral animal respiration appears to be a direct function of decreased photosynthetically fixed carbon availability, and to be an immediate response to daily carbon input. Decreased carbon availability to the host animal at 35 m was a consequence of both decreased net carbon fixation and decreased percentage of net fixed carbon translocated to the host. The daily CZAR at 35 m was less than half that at 3m. Mean CZAR at 35 m was 78%, suggesting that deeper corals have an obligate requirement for heterotrophically obtained carbon. By contrast, corals from 3m, which displayed a mean CZAR of 157%, appeared to be photo trophic with respect to carbon required for respiration. Altered trophic strategies with depth were confirmed by daily carbon budgets calculated for average size corals from both depths. Multiple correlation tests of all parameters confirmed the utility of expressing production and respiration measures in terms of unit surface area. However, significant correlations with other normalizing parameters were found, and their usefulness discussed.

Photosynthesis below the surface in a cryptic microbial mat

2002 ◽  
Vol 1 (4) ◽  
pp. 295-304 ◽  
Author(s):  
Lynn J. Rothschild ◽  
Lorraine J. Giver
Keyword(s):  
Carbon Fixation ◽  
Early Earth ◽  
Cyanobacterial Mat ◽  
Fixed Carbon ◽  
Daily Production ◽  
Near Surface ◽  
Surface Conditions ◽  
A Value ◽  
Subsurface Environments

The discovery of subsurface communities has encouraged speculation that such communities might be present on planetary bodies exposed to harsh surface conditions, including the early Earth. While the astrobiology community has focused on the deep subsurface, near-subsurface environments are unique in that they provide some protection while allowing partial access to photosynthetically active radiation. Previously we identified near-surface microbial communities based on photosynthesis. Here we assess the productivity of such an ecosystem by measuring in situ carbon fixation rates in an intertidal marine beach through a diurnal cycle, and find them surprisingly productive. Gross fixation along a transect (99×1 m) perpendicular to the shore was highly variable and depended on factors such as moisture and mat type, with a mean of ~41 mg C fixed m−2 day−1. In contrast, an adjacent well-established cyanobacterial mat dominated by Lyngbya aestuarii was ~12 times as productive (~500 mg C fixed m−2 day−1). Measurements made of the Lyngbya mat at several times per year revealed a correlation between total hours of daylight and gross daily production. From these data, annual gross fixation was estimated for the Lyngbya mat and yielded a value of ~1.3×105 g m−2 yr−1. An analysis of pulse-chase data obtained in the study in conjunction with published literature on similar ecosystems suggests that subsurface interstitial mats may be an overlooked endogenous source of organic carbon, mostly in the form of excreted fixed carbon.

Inorganic carbon fixation in ice-covered lakes of the McMurdo Dry Valleys

2019 ◽  
Vol 31 (3) ◽  
pp. 123-132 ◽  
Author(s):  
Trista J. Vick-Majors ◽  
John C. Priscu
Keyword(s):  
Aquatic Ecosystems ◽  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Dry Valleys ◽  
Ammonia Oxidizers ◽  
Fixed Carbon ◽  
Carbon Supply ◽  
Gain Energy ◽  
Photosynthetic Microorganisms ◽  
Dark Carbon Fixation

AbstractInorganic carbon fixation, usually mediated by photosynthetic microorganisms, is considered to form the base of the food chain in aquatic ecosystems. In high-latitude lakes, lack of sunlight owing to seasonal solar radiation limits the activity of photosynthetic plankton during the polar winter, causing respiration-driven demand for carbon to exceed supply. Here, we show that inorganic carbon fixation in the dark, driven by organisms that gain energy from chemical reactions rather than sunlight (chemolithoautotrophs), provides a significant influx of fixed carbon to two permanently ice-covered lakes (Fryxell and East Bonney). Fryxell, which has higher biomass per unit volume of water, had higher rates of inorganic dark carbon fixation by chemolithoautotrophs than East Bonney (trophogenic zone average 1.0 µg C l−1 d−1vs 0.08 µg C l−1 d−1, respectively). This contribution from dark carbon fixation was partly due to the activity of ammonia oxidizers, which are present in both lakes. Despite the potential importance of new carbon input by chemolithoautotrophic activity, both lakes remain net heterotrophic, with respiratory demand for carbon exceeding supply. Dark carbon fixation increased the ratio of new carbon supply to respiratory demand from 0.16 to 0.47 in Fryxell, and from 0.14 to 0.22 in East Bonney.

Regulation of assimilate partitioning in leaves

2000 ◽  
Vol 27 (6) ◽  
pp. 507 ◽  
Author(s):  
Charlotte E. Lewis ◽  
Graham Noctor ◽  
David Causton ◽  
Christine H. Foyer
Keyword(s):  
Carbon Fixation ◽  
Starch Synthesis ◽  
Co2 Concentration ◽  
Building Blocks ◽  
Energy Budgets ◽  
Assimilate Partitioning ◽  
Fixed Carbon ◽  
Carbon And Nitrogen ◽  
Cellular Energy ◽  
Photosynthetic Carbon

Concepts of the regulation of assimilate partitioning in leaves frequently consider only the allocation of carbon between sucrose and starch synthesis, storage and export. While carbohydrate metabolism accounts for a large proportion of assimilated carbon, such analyses provide only a restricted view of carbon metabolism and partitioning in leaf cells since photosynthetic carbon fixation provides precursors for all other biosynthetic pathways in the plant. Most of these precursors are required for biosynthesis of amino acids that form the building blocks for many compounds in plants. We have used leaf carbon : nitrogen ratios to calculate the allocation of photosynthetic electrons to the assimilation of nitrogen necessary for amino acid formation, and conclude that this allocation is variable but may be higher than values often quoted in the literature. Respiration is a significant fate of fixed carbon. In addition to supplying biosynthetic precursors, respiration is required for energy production and may also act, in both light and dark, to balance cellular energy budgets. We have used growth CO2 concentration and irradiance to modify source activity in Lolium temulentum in order to explore the interactions between photosynthetic carbon and nitrogen assimilation, assimilate production, respiration and export. It is demonstrated that there is a robust correlation between source activity and foliar respiration rates. Under some conditions concomitant increases in source activity and respiration may be necessary to support faster growth. In other conditions, increases in respiration appear to result from internal homeostatic mechanisms that may be candidate targets for increasing yield.

scholarly journals Metabolic differences between symbiont subpopulations in the deep-sea tubeworm Riftia pachyptila

2020 ◽  
Author(s):  
Tjorven Hinzke ◽  
Manuel Kleiner ◽  
Mareike Meister ◽  
Rabea Schlüter ◽  
Christian Hentschker ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Statistical Evaluation ◽  
Gradient Centrifugation ◽  
Riftia Pachyptila ◽  
Metabolic Diversity ◽  
Host Animal ◽  
Host Interaction ◽  
Sulfur Oxidizing ◽  
Differentiation Stage ◽  
Vent Tube

AbstractThe hydrothermal vent tube worm Riftia pachyptila lives in intimate symbiosis with intracellular sulfur-oxidizing gammaproteobacteria. Although the symbiont population consists of a single 16S rRNA phylotype, bacteria in the same host animal exhibit a remarkable degree of metabolic diversity: They simultaneously utilize two carbon fixation pathways and various energy sources and electron acceptors. Whether these multiple metabolic routes are employed in the same symbiont cells, or rather in distinct symbiont subpopulations, was unclear. As Riftia symbionts vary considerably in cell size and shape, we enriched individual symbiont cell sizes by density gradient centrifugation in order to test whether symbiont cells of different sizes show different metabolic profiles. Metaproteomic analysis and statistical evaluation using clustering and random forests, supported by microscopy and flow cytometry, strongly suggest that Riftia symbiont cells of different sizes represent metabolically dissimilar stages of a physiological differentiation process: Small symbionts actively divide and may establish cellular symbiont-host interaction, as indicated by highest abundance of the cell division key protein FtsZ and highly abundant chaperones and porins in this initial phase. Large symbionts, on the other hand, apparently do not divide, but still replicate DNA, leading to DNA endoreduplication. Highest abundance of enzymes for CO2 fixation, carbon storage and biosynthesis in large symbionts indicates that in this late differentiation stage the symbiont’s metabolism is efficiently geared towards the production of organic material. We propose that this division of labor between smaller and larger symbionts benefits the productivity of the symbiosis as a whole.

scholarly journals The World of Algae Reveals a Broad Variety of Cryptochrome Properties and Functions

2021 ◽  
Vol 12 ◽  
Author(s):  
Jan Petersen ◽  
Anxhela Rredhi ◽  
Julie Szyttenholm ◽  
Sabine Oldemeyer ◽  
Tilman Kottke ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Algal Cell ◽  
Algal Species ◽  
Life Cycles ◽  
Land Plants ◽  
Abiotic Factor ◽  
Secondary Endosymbiosis ◽  
Biological Clocks ◽  
Terrestrial Habitats ◽  
Broad Variety

Algae are photosynthetic eukaryotic (micro-)organisms, lacking roots, leaves, and other organs that are typical for land plants. They live in freshwater, marine, or terrestrial habitats. Together with the cyanobacteria they contribute to about half of global carbon fixation. As primary producers, they are at the basis of many food webs and they are involved in biogeochemical processes. Algae are evolutionarily distinct and are derived either by primary (e.g., green and red algae) or secondary endosymbiosis (e.g., diatoms, dinoflagellates, and brown algae). Light is a key abiotic factor needed to maintain the fitness of algae as it delivers energy for photosynthesis, regulates algal cell- and life cycles, and entrains their biological clocks. However, excess light can also be harmful, especially in the ultraviolet range. Among the variety of receptors perceiving light information, the cryptochromes originally evolved as UV-A and blue-light receptors and have been found in all studied algal genomes so far. Yet, the classification, biophysical properties, wavelength range of absorbance, and biological functions of cryptochromes are remarkably diverse among algal species, especially when compared to cryptochromes from land plants or animals.

scholarly journals Coral Productivity Is Co-Limited by Bicarbonate and Ammonium Availability

2020 ◽  
Vol 8 (5) ◽  
pp. 640 ◽  
Author(s):  
Stephane Roberty ◽  
Eric Béraud ◽  
Renaud Grover ◽  
Christine Ferrier-Pagès
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Physiological State ◽  
Stylophora Pistillata ◽  
Carbon Availability ◽  
Carbon And Nitrogen ◽  
Positive Effects ◽  
Coral Holobiont ◽  
Photosynthetic Performances ◽  
The Impact

The nitrogen environment and nitrogen status of reef-building coral endosymbionts is one of the important factors determining the optimal assimilation of phototrophic carbon and hence the growth of the holobiont. However, the impact of inorganic nutrient availability on the photosynthesis and physiological state of the coral holobiont is partly understood. This study aimed to determine if photosynthesis of the endosymbionts associated with the coral Stylophora pistillata and the overall growth of the holobiont were limited by the availability of dissolved inorganic carbon and nitrogen in seawater. For this purpose, colonies were incubated in absence or presence of 4 µM ammonium and/or 6 mM bicarbonate. Photosynthetic performances, pigments content, endosymbionts density and growth rate of the coral colonies were monitored for 3 weeks. Positive effects were observed on coral physiology with the supplementation of one or the other nutrient, but the most important changes were observed when both nutrients were provided. The increased availability of DIC and NH4+ significantly improved the photosynthetic efficiency and capacity of endosymbionts, in turn enhancing the host calcification rate. Overall, these results suggest that in hospite symbionts are co-limited by nitrogen and carbon availability for an optimal photosynthesis.

Phosphoenolpyruvate carboxylase mediated carbon flow in a cyanobacterium

1988 ◽  
Vol 66 (2) ◽  
pp. 93-99 ◽  
Author(s):  
George W. Owttrim ◽  
Brian Colman
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Protein Production ◽  
Carbon Fixation ◽  
Fixed Carbon ◽  
Free System ◽  
Pyruvate Orthophosphate Dikinase ◽  
Orthophosphate Dikinase ◽  
Phosphoglyceric Acid ◽  
A Cell

The source of the substrate phosphoenolpyruvate (PEP) for phosphoenolpyruvate carboxylase (PEP-case) activity in the cyanobacterium Coccochloris peniocystis has been investigated, as well as possible sinks for this carbon. PEP was not produced by pyruvate orthophosphate dikinase, as this activity was not detectable in cell-free lysates. PEP is supplied from photosynthetically or glycolytically produced 3-phosphoglyceric acid (3-PGA), as carbon was observed to flow from 3-PGA to C4 acids in a cell-free system. This indicates PEP-case activity is dependent on photosynthetically fixed carbon and thus two separate carbon fixation reactions occur in the cell in the light. Estimates of the in vivo concentrations of various metabolites indicates that neither substrate nor inhibitor concentrations limit enzyme activity in vivo. Thus PEP-case activity in vivo appears to be limited by the supply of PEP and is, therefore, high in the light and low in the dark. The nitrogen storage product cyanophycin was identified as one sink for carbon fixed by PEP-case. As a culture aged, cyanophycin production increased, while chlorophyll and protein production decreased.

scholarly journals Heterotrophic Carbon Fixation in a Salamander-Alga Symbiosis

2020 ◽  
Author(s):  
John A. Burns ◽  
Ryan Kerney ◽  
Solange Duhamel
Keyword(s):  
Inorganic Carbon ◽  
Carbon Fixation ◽  
Minor Role ◽  
Host Animal ◽  
Algal Symbionts ◽  
Algal Symbiont ◽  
Oophila Amblystomatis ◽  
Modes Of Interaction ◽  
Egg Capsule

AbstractThe unique symbiosis between a vertebrate salamander, Ambystoma maculatum, and unicellular green alga, Oophila amblystomatis, involves multiple modes of interaction. These include an ectosymbiotic interaction where the alga colonizes the egg capsule, and an intracellular interaction where the alga enters tissues and cells of the salamander. One common interaction in mutualist photosymbioses is the transfer of photosynthate from the algal symbiont to the host animal. In the A. maculatum-O. amblystomatis interaction, there is conflicting evidence regarding whether the algae in the egg capsule transfer chemical energy captured during photosynthesis to the developing salamander embryo. In experiments where we took care to separate the carbon fixation contributions of the salamander embryo and algal symbionts, we show that inorganic carbon fixed by A. maculatum embryos reaches 2% of the inorganic carbon fixed by O. amblystomatis algae within an egg capsule after 2 hours in the light. After 2 hours in the dark, inorganic carbon fixed by A. maculatum embryos is 800% of the carbon fixed by O. amblystomatis algae within an egg capsule. Using photosynthesis inhibitors we show that A. maculatum embryos and O. amblystomatis algae compete for available inorganic carbon within the egg capsule environment. Our results confirm earlier studies suggesting a role of heterotrophic carbon fixation during vertebrate embryonic development. Our results also show that the considerable capacity of developing A. maculatum embryos for inorganic carbon fixation precludes our ability to distinguish any minor role of photosynthetically transferred carbon from algal symbionts to host salamanders using bicarbonate introduced to the egg system as a marker.

scholarly journals Sinks for Plant Surplus Carbon Explain Several Ecological Phenomena

2022 ◽  
Author(s):  
Cindy E. Prescott
Keyword(s):  
Mycorrhizal Fungi ◽  
Carbon Fixation ◽  
High Energy ◽  
Cellular Damage ◽  
Primary Metabolism ◽  
Fixed Carbon ◽  
Floral Nectaries ◽  
Root Grafts ◽  
Micro Organisms ◽  
Understory Trees

Abstract Plants engage in many processes and relationships that appear to be wasteful of the high-energy compounds that they produce through carbon fixation and photosynthesis. For example, living trees keep leafless tree stumps alive (i.e. respiring) and support shaded understory trees by sharing carbohydrates through root grafts or mycorrhizal fungal networks. Plants exude a variety of organic compounds from their roots and leaves, which support abundant rhizosphere and phyllosphere microbiomes. Some plants release substantial amounts of sugar via extra-floral nectaries, which enrich throughfall and alter lichen communities beneath the canopy. Large amounts of photosynthetically fixed carbon are transferred to root associates such as mycorrhizal fungi and N-fixing micro-organisms. In roots, some fixed C is respired through an alternative non-phosphorylating pathway that oxidizes excess sugar. Each of these processes is most prevalent when plants are growing under mild-to-moderate deficiencies or nutrients or water, or under high light or elevated atmospheric CO2. Under these conditions, plants produce more fixed carbon than they can use for primary metabolism and growth, and so have ‘surplus carbon’. To prevent cellular damage, these compounds must be transformed into other compounds or removed from the leaf. Each of the above phenomena represents a potential sink for these surplus carbohydrates. The fundamental ‘purpose’ of these phenomena may therefore be to alleviate the plant of surplus fixed C.

Fate of photosynthetic fixed carbon in light- and shade-adapted colonies of the symbiotic coral Stylophora pistillata

1984 ◽  
Vol 222 (1227) ◽  
pp. 181-202 ◽  
Keyword(s):  
Growth Rates ◽  
Specific Growth ◽  
Reductase Activity ◽  
Ammonium Uptake ◽  
Fixed Carbon ◽  
Stylophora Pistillata ◽  
Uptake Rates ◽  
Specific Growth Rates

The total daily flux of photosynthetically fixed carbon in light- and shade-adapted phenotypes of the symbiotic coral, Stylophora pistillata , was quantified. Light adapted corals fixed four times as much carbon and respired twice as much as shade corals. Specific growth rates of zooxanthellae in situ were estimated from average daily mitotic indices and from ammonium uptake rates (nitrate uptake or nitrate reductase activity could not be demonstrated). Specific growth rates were very low, demonstrating that of the total net carbon fixed daily, only a small fraction (less than 5 %) goes into zooxanthellae cell growth. The balance of the net fixed carbon (more than 95 %) is translocated to the host. New and conventional methods of measuring total daily translocation were compared. The ‘growth rate’ method, which does not employ 14 C, emerged as superior to the conventional in vitro and in vivo methods. The contribution of translocated carbon to animal maintenance res­piration (czar) was 143 % in light corals and 58 % in shade corals. Thus, translocation in the former could supply not only the total daily carbon needed for respiration but also a fraction of the carbon needed for growth. Whereas light-adapted corals released only 6%, shade-adapted corals released almost half of their total fixed carbon as dissolved or particulate organic material. This much higher throughput of organic carbon may possibly benefit the heterotrophic microbial community in shade environments.

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