A rapid technique for preparation of aquatic macrophyte samples for measuring 14C incorporation

Lewis, Marlon R.; Kemp, W. Michael; Cunningham, Jeffrey J.; Stevenson, J. Court

doi:10.1016/0304-3770(82)90054-7

Cited by 9 publications

(3 citation statements)

References 6 publications

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“…Above-and belowground parts were processed for measuring labelled PO 14 C according to Lewis et al (1982) and Modigh et al (1998). Tissues were soaked in diluted HCl (0.1 N) to remove adsorbed carbonates, and then into 10 ml of concentrated nitric acid (65%) for 48 h. One ml of the acid extract was diluted with 9 ml Tris buffer (0.75 M), and 1 ml of this solution was diluted in 4 ml of scintillation liquid (Ultima Gold TM ).…”

Section: Zostera Noltii Culture With Labelled Dissolved Organic Carbomentioning

confidence: 99%

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Brun¹,

Vergara²,

Navarro³

et al. 2003

Mar. Ecol. Prog. Ser.

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The effects of macroalgae blooms on seagrasses were assessed by shading Zostera noltii Hornem. with Ulva rigida C. Agardh mats under laboratory and field conditions. In the laboratory, where there was no direct contact between U. rigida and Z. noltii, leaf, rhizome, and root elongation rates, as well as gross production, declined as a function of U. rigida layers, causing a mobilization of non-structural carbohydrates in both above-and belowground tissues to meet carbon demands. However, when shading was performed in the field, where direct contact exists between Z. noltii and U. rigida, Z. noltii responses were not proportional to the number of Ulva layers. Elongation rates and gross production were reduced by U. rigida shading, with the lowest values under 2 Ulva layers, while there were no significant differences between controls and 4 U. rigida layers. This suggests another Ulva effect occurs besides shading. To test the likely effect of dissolved organic carbon (DOC) derived from U. rigida, Z. noltii plants were cultured under light limitation with radioactive dissolved organic carbon (DO 14 C) released by U. rigida. Plants cultured under a full DO 14 C load showed a significant enhancement of growth. The DO 14 C disappeared from the culture medium during the first 4 d of culture as a linear function of external DO 14 C concentration. This was coupled to a linear increase of radioactive particulate organic carbon (PO 14 C) in aboveground tissues, while a substantial part of this PO 14 C was allocated in belowground tissues. Overall, the PO 14 C incorporated in Z. noltii plants represented ca. 20 to 25% of the DO 14 C which had disappeared. Therefore, a net transfer of DO 14 C from U. rigida to Z. noltii has been documented. Other additional possibilities, such as a light quality effect or other kind of signals (i.e. growth factors), are discussed.KEY WORDS: Eutrophication · Heterotrophic DOC uptake · Dissolved organic carbon · Seagrass · Non-structural carbohydrates · Light reduction Resale or republication not permitted without written consent of the publisher

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Section: Zostera Noltii Culture With Labelled Dissolved Organic Carbomentioning

confidence: 99%

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Brun¹,

Vergara²,

Navarro³

et al. 2003

Mar. Ecol. Prog. Ser.

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“…The predominate use of oxygen procedures is ostensibly due to low cost and simplicity as compared to macrophyte 14 C protocols. While 14 Clabeled phytoplankton can be filtered and dissolved directly into liquid scintillation solution, macrophyte tissue must be either dry combusted (Berger & Bate 1986, Dunton & Schell 1986 or solubilized (Lewis et al 1982, Arnold & Littler 1985 prior to 14 C counts. Macrophyte experiments generate large volumes of radioactively labeled seawater, which accrue additional costs in storage, shipping, and disposal.…”

Section: Introductionmentioning

confidence: 99%

Stable isotope (13C) and O2 micro-optode alternatives for measuring photosythesis in seaweeds

Miller¹,

Dunton²

2007

Mar. Ecol. Prog. Ser.

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Many photosynthetic studies with macroalgae are based on oxygen evolution. This approach is preferred over 14 C tracer techniques since oxygen electrodes are generally inexpensive and radioactive wastes are not produced. Nevertheless, oxygen techniques do not directly measure carbon assimilation; thus, primary production estimates rely on the conversion of oxygen units to carbon units via a photosynthetic quotient, which may vary depending on physiological state and nutrient status of the alga. We present in detail 2 methods for measuring photosynthesis in macroalgae, both of which should enhance prospects for photosynthetic research, particularly under field conditions. First, a carbon uptake procedure is described which relies on incorporation of a stable 13 C isotope label. Important advantages of the 13 C method include simplicity of sample processing, avoidance of environmental hazards and restrictions of radioactive 14 C, and ability to be used as a dual tracer with 15 N. Second, we employed a fiber-optic micro-optode system for measurement of dissolved oxygen. The fluorescence-based optodes stabilize quickly (<15 s), do not consume oxygen, and are simple to set up and maintain. Oxygen and carbon photosynthesis were assessed concurrently in a light/dark chamber design. Both techniques resolved significant decreases in lightsaturated photosynthesis (P max) in the kelp Laminaria hyperborea collected subtidally at 10 m compared to kelp at 0 m (from mean low tide). Oxygen and carbon photosynthetic rates agreed well with published values and were mutually consistent, considering a reasonable photosynthetic quotient. Estimated measurement errors (< 2%) associated with the 13 C technique were less than intrinsic variation (> 20%) in photosynthetic rates between kelp individuals with similar light histories. Both techniques should provide an alternative to traditional photosynthetic protocols and stimulate further primary production research in macrophytes.

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“…Nitrate was analyzed on the filtrate by the method of Strickland and Parsons (1972) modified for smaller volumes. Analysis of "C in the plant tissue was by a modified method of Lewis et al (1982). The plants were dried for 12 h at 65" C, weighed and ground in a tissue homogenizer.…”

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confidence: 99%

Inhibition of Carbon Uptake and Stimulation of Nitrate Uptake at Low Salinities in Fucus Distichus (Phaeophyceae)

Rueter

Robinson

1986

J Phycol

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Inorganic carbon and nitrate uptake were examined in whole plants of Fucus distichus L. (Powell) incubated in dilutions of synthetic ocean water and media with different concentrations of Na+, K+ and Cl−. Reduction in salinity from normal seawater (33 ppt) decreased carbon uptake rate but increased nitrate uptake rate by 50% each. Substitution of K+ for Na+ at constant ionic strength decreased nitrate uptake. Substitution of K+ or mannitol for Na+ decreased carbon uptake. Neither the uptake of nitrate or carbon was changed by substituting SO42‐ for Cl−. Ionophores, valinomycin and monensin, inhibited both nitrate uptake and carbon fixation from 20 to 70% of control rates. The stimulation of nitrate uptake at low salinity may be beneficial to plants in estuarine tidal environments in which nitrate is supplied by the fresh water source.

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A rapid technique for preparation of aquatic macrophyte samples for measuring 14C incorporation

Cited by 9 publications

References 6 publications

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Stable isotope (13C) and O2 micro-optode alternatives for measuring photosythesis in seaweeds

Inhibition of Carbon Uptake and Stimulation of Nitrate Uptake at Low Salinities in Fucus Distichus (Phaeophyceae)

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