Determination of particulate organic carbon and nitrogen

Ehrhardt, Manfred; Koeve, Wolfgang

doi:10.1002/9783527613984.ch17

Cited by 41 publications

(30 citation statements)

References 23 publications

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“…POC and PON measurements of the EIFEX and F. kerguelensis samples were analyzed using a C/N Analyser (Euro EA Elemental Analyser) after Ehrhard and Koeve (1999). The POP content of all samples was determined colorimetrically using the method from Hansen and Koroleff (1999).…”

Section: Methodsmentioning

confidence: 99%

Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms Fragilariopsis kerguelensis and Chaetoceros dichaeta

2007

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Abstract.The interaction between iron availability and the phytoplankton elemental composition was investigated during the in situ iron fertilization experiment EIFEX and in laboratory experiments with the Southern Ocean diatom species Fragilariopsis kerguelensis and Chaetoceros dichaeta. Contrary to other in situ iron fertilization experiments we observed an increase in the BSi:POC, BSi:PON, and BSi:POP ratios within the iron fertilized patch during EIFEX. This is possibly caused by a relatively stronger increase in diatom abundance compared to other phytoplankton groups and does not necessarily represent the amount of silicification of single diatom cells. In laboratory experiments with F. kerguelensis and C. dichaeta no changes in the POC:PON, PON:POP, and POC:POP ratios were found with changing iron availability in both species. BSi:POC, BSi:PON, and BSi:POP ratios were significantly lower in the high iron treatments compared to the controls. In F. kerguelensis this was caused by a decrease in cellular BSi concentrations and therefore possibly less silicification. In C. dichaeta no change in cellular BSi concentration was found. Here lower BSi:POC, BSi:PON, and BSi:POP ratios were caused by an increase in cellular C, N, and P under high iron conditions. These results indicate that iron limitation does not always increase silicification in diatoms and that changes in the BSi:POC, BSi:PON, and BSi:POP ratios under iron fertilization in the field are caused by a variety of different mechanisms. Our results therefore imply that simple cause-and-effect relationships are not always applicable for modeling of elemental ratios.

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Section: Methodsmentioning

confidence: 99%

Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms Fragilariopsis kerguelensis and Chaetoceros dichaeta

2007

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“…TPC and POC were measured on separate filters using an "Euro EA Elemental Analyser" (Ehrhardt and Koeve, 1999). The filter for POC analysis was treated with fuming HCl (≈ 10 h) to remove all inorganic carbon.…”

Section: Production Rates Of Particulate Inorganic and Organic Carbonmentioning

confidence: 99%

Influence of CO2 and nitrogen limitation on the coccolith volume of Emiliania huxleyi (Haptophyta)

et al. 2012

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Abstract. Coccolithophores, a key phytoplankton group, are one of the most studied organisms regarding their physiological response to ocean acidification/carbonation. The biogenic production of calcareous coccoliths has made coccolithophores a promising group for paleoceanographic research aiming to reconstruct past environmental conditions. Recently, geochemical and morphological analyses of fossil coccoliths have gained increased interest in regard to changes in seawater carbonate chemistry. The cosmopolitan coccolithophore Emiliania huxleyi (Lohm.) Hay and Mohler was cultured over a range of pCO 2 levels in controlled laboratory experiments under nutrient replete and nitrogen limited conditions. Measurements of photosynthesis and calcification revealed, as previously published, an increase in particulate organic carbon production and a moderate decrease in calcification from ambient to elevated pCO 2 . The enhancement in particulate organic carbon production was accompanied by an increase in cell diameter. Changes in coccolith volume were best correlated with the coccosphere/cell diameter and no significant correlation was found between the coccolith volume and the particulate inorganic carbon production. The conducted experiments revealed that the coccolith volume of E. huxleyi is variable with aquatic CO 2 concentration but its sensitivity is rather small in comparison with its sensitivity to nitrogen limitation. Comparing coccolith morphological and geometrical parameters like volume, mass and size to physiological parameters under controlled laboratory conditions is an important step to understand variations in fossil coccolith geometry.

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“…Two sub-samples from each flask were filtrated onto precombusted (525 • C for 7 h) GF/F filters and frozen at −20 • C. For POC analysis filters were fumed over HCl for 24 h to remove all inorganic carbon and afterwards all filters were measured on a Euro EA Elemental Analyser (Ehrhardt and Koeve, 1999). PIC (particulate inorganic carbon) was calculated from the difference of TPC and POC.…”

Section: Tpc Poc Pic Tpnmentioning

confidence: 99%

Effects of long-term high CO2 exposure on two species of coccolithophores

2010

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Abstract. The physiological performance of two coccolithophore species, Emiliania huxleyi and Coccolithus braarudii, was investigated during long-term exposure to elevated pCO 2 levels. Mono-specific cultures were grown over 152 (E. huxleyi) and 65 (C. braarudii) generations while pCO 2 was gradually increased to maximum levels of 1150 µatm (E. huxleyi) and 930 µatm (C. braarudii) and kept constant thereafter. Rates of cell growth and cell quotas of particulate organic carbon (POC), particulate inorganic carbon (PIC) and total particulate nitrogen (TPN) were determined repeatedly throughout the incubation period. Increasing pCO 2 caused a decrease in cell growth rate of 9% and 29% in E. huxleyi and C. braarudii, respectively. In both species cellular PIC:TPN and PIC:POC ratios decreased in response to rising pCO 2 , whereas no change was observed in the POC:TPN ratios of E. huxleyi and C. braarudii. These results are consistent with those obtained in shorter-term high CO 2 exposure experiments following abrupt pertubations of the seawater carbonate system and indicate that for the strains tested here a gradual CO 2 increase does not alleviate CO 2 /pH sensitivity.

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Determination of particulate organic carbon and nitrogen

Cited by 41 publications

References 23 publications

Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms <i>Fragilariopsis kerguelensis</i> and <i>Chaetoceros dichaeta</i>

Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms <i>Fragilariopsis kerguelensis</i> and <i>Chaetoceros dichaeta</i>

Influence of CO<sub>2</sub> and nitrogen limitation on the coccolith volume of <I>Emiliania huxleyi</I> (Haptophyta)

Effects of long-term high CO<sub>2</sub> exposure on two species of coccolithophores

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Determination of particulate organic carbon and nitrogen

Cited by 41 publications

References 23 publications

Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms &lt;i&gt;Fragilariopsis kerguelensis&lt;/i&gt; and &lt;i&gt;Chaetoceros dichaeta&lt;/i&gt;

Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms &lt;i&gt;Fragilariopsis kerguelensis&lt;/i&gt; and &lt;i&gt;Chaetoceros dichaeta&lt;/i&gt;

Influence of CO&lt;sub&gt;2&lt;/sub&gt; and nitrogen limitation on the coccolith volume of &lt;I&gt;Emiliania huxleyi&lt;/I&gt; (Haptophyta)

Effects of long-term high CO&lt;sub&gt;2&lt;/sub&gt; exposure on two species of coccolithophores

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Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms <i>Fragilariopsis kerguelensis</i> and <i>Chaetoceros dichaeta</i>

Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms <i>Fragilariopsis kerguelensis</i> and <i>Chaetoceros dichaeta</i>

Influence of CO<sub>2</sub> and nitrogen limitation on the coccolith volume of <I>Emiliania huxleyi</I> (Haptophyta)

Effects of long-term high CO<sub>2</sub> exposure on two species of coccolithophores