scholarly journals Benthic foraminifera as trophic links between phytodetritus and benthic metazoans: carbon and nitrogen isotopic evidence

2008 ◽  
Vol 357 ◽  
pp. 153-164 ◽  
Author(s):  
H Nomaki ◽  
NO Ogawa ◽  
N Ohkouchi ◽  
H Suga ◽  
T Toyofuku ◽  
...  
Keyword(s):  
Benthic Foraminifera ◽  
Carbon And Nitrogen ◽  
Isotopic Evidence ◽  
Trophic Links

Carbon and nitrogen budgets and respiration rates of selected foraminifera of the Gullmar Fjord in Sweden

2021 ◽  
Author(s):  
Julia Wukovits ◽  
Nicolaas Glock ◽  
Johanna Nachbagauer ◽  
Petra Heinz ◽  
Wolfgang Wanek ◽  
...  
Keyword(s):  
Benthic Foraminifera ◽  
Environmental Changes ◽  
Microscopy Imaging ◽  
Test Volume ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Respiration Rates ◽  
Feeding Experiments ◽  
Nitrogen Intake ◽  
Oxygen Concentrations

<p>Benthic foraminifera are highly abundant, ubiquitous marine protists, with many species feeding on microalgae or phytodetritus. Knowledge about carbon and nitrogen budgets and metabolic activities of benthic foraminifera can help to increase our understanding about their ecology and their role in aquatic biogeochemistry at the sediment-water interface. This can further increase their application as proxies for environmental changes. Shifts in the benthic foraminiferal communities of the Swedish Gullmars Fjord document the shift from well oxygenated bottom waters to seasonal hypoxia at its deepest location the Alsbäck Deep (125 m), during the last century.</p><p>So far there are only investigations available relating foraminiferal community composition with increased primary productivity and resulting hypoxia in this Fjord. In contrast, studies about the species-specific feeding ecology or food derived foraminiferal carbon and nitrogen fluxes are scarce.</p><p>Therefore, laboratory feeding experiments and respiration rate measurements were carried out with <em>Bulimina marginata</em>, <em>Cassidulina laevigata</em> and <em>Globobulima turgida</em>, abundant foraminifera in such environments, collected in August 2017.</p><p>Experiments were conducted to evaluate the carbon and nitrogen intake and turnover of dual (<sup>13</sup>C and <sup>15</sup>N) isotope labelled <em>Phaeodactylum tricornutum</em> detritus; detritus of a common diatom in the Gullmar Fjord. For the feeding experiments, foraminifera were incubated at 9.1°C in the dark, in sterile filtered seawater at ambient oxygen concentrations. The foraminifera were fed for a period of 24 hours and subsequently incubated without food for another 24 hours. After each incubation cycle, foraminiferal respiration rates were measured. The individuals were analyzed via Elemental Analyzer-Isotope Ratio Mass Spectroscopy to evaluate <sup>13</sup>C/<sup>12</sup>C and <sup>15</sup>N/<sup>14</sup>N ratios and their bulk content of organic carbon and nitrogen.</p><p>Additionally, we present carbon and nitrogen to volume ratios for the foraminifera <em>B. marginata</em>, <em>C. laevigata</em>, <em>G. turgida</em>, <em>G. auriculata</em> and <em>Nonionella turgida</em>, as derived from elemental analysis and light microscopy imaging.</p><p>The results show, that <em>B. marginata</em>, an opportunistic species associated with high fluxes of organic matter, had the highest rate of specific carbon and nitrogen intake and turnover. <em>Cassidulina laevigata</em>, a species that co-occurs with fresh phytodetritus and does not tolerate very low oxygen concentrations, showed lower carbon and nitrogen intake rates. <em>Globobulima turgida</em>, a denitrifying infaunal species that thrives under hypoxia, showed the lowest specific carbon and nitrogen intake and turnover rates. Respiration rates of all species did not depend on incubation with or without a food source. The foraminifera showed similar carbon and nitrogen densities per test volume across all species.</p><p>Overall this study helps to improve the knowledge on the nutritional ecology of the investigated species, demonstrating the close relation between feeding/metabolic rates and their environmental niche and highlighting the need to introduce foraminiferal data in future marine carbon and nitrogen flux models.</p>

Carbon and Nitrogen Isotopic Evidence on Basketmaker II Diet at Cedar Mesa, Utah

KIVA ◽  
1994 ◽  
Vol 60 (2) ◽  
pp. 239-255 ◽  
Author(s):  
Brian Chisholm ◽  
R. G. Matson
Keyword(s):  
Carbon And Nitrogen ◽  
Isotopic Evidence

scholarly journals Carbon and Nitrogen Uptake of Calcareous Benthic Foraminifera along a Depth-Related Oxygen Gradient in the OMZ of the Arabian Sea

2016 ◽  
Vol 7 ◽  
Author(s):  
Annekatrin J. Enge ◽  
Julia Wukovits ◽  
Wolfgang Wanek ◽  
Margarete Watzka ◽  
Ursula F. M. Witte ◽  
...  
Keyword(s):  
Nitrogen Uptake ◽  
Benthic Foraminifera ◽  
Arabian Sea ◽  
Carbon And Nitrogen ◽  
Oxygen Gradient

Metabolic signalling and the partitioning of resources in plant storage organs

1999 ◽  
Vol 133 (3) ◽  
pp. 243-249 ◽  
Author(s):  
NIGEL G. HALFORD
Keyword(s):  
Dry Weight ◽  
Wild Relatives ◽  
Crop Plants ◽  
Wild Plants ◽  
Young Plant ◽  
Carbon And Nitrogen ◽  
Cultivated Potato ◽  
Metabolic Signalling ◽  
Storage Organs ◽  
Plant Storage

The most important harvested organs of crop plants, such as seeds, tubers and fruits, are often described as assimilate sinks. They play little or no part in the fixation of carbon through the production of sugars through photosynthesis, or in the uptake of nitrogen and sulphur, but import these assimilated resources to support metabolism and to store them in the form of starch, oils and proteins. Wild plants store resources in seeds and tubers to later support an emergent young plant. Cultivated crops are effectively storing resources to provide us with food and many have been bred to accumulate much more than would be required otherwise. For example, approximately 80% of a cultivated potato plant's dry weight is contained in its tubers, ten times the proportion in the tubers of its wild relatives (Inoue & Tanaka 1978). Cultivation and breeding has brought about a shift in the partitioning of carbon and nitrogen assimilate between the organs of the plant.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

Precipitation in silicon: Microanalysis

1988 ◽  
Vol 46 ◽  
pp. 474-475
Author(s):  
R.W. Carpenter
Keyword(s):  
Transition Metals ◽  
Spatial Resolution ◽  
Thin Foil ◽  
Precipitation Reaction ◽  
High Current ◽  
Reaction Products ◽  
Carbon And Nitrogen ◽  
Dielectric Layers ◽  
Precipitation Processes ◽  
Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

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