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 budgets of two Ascidians and their symbiont, Prochloron, in a tropical seagrass meadow

1993 ◽  
Vol 44 (1) ◽  
pp. 173 ◽  
Author(s):  
I Koike ◽  
M Yamamuro ◽  
PC Pollard
Keyword(s):  
Organic Carbon ◽  
Organic Nitrogen ◽  
Carbon Budget ◽  
Seagrass Meadow ◽  
Inorganic Nitrogen ◽  
Host Animal ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Respiration Rates ◽  
Surrounding Environment

Two species of ascidian, Didemnum molle Herdman and Lissoclinum voeltzkowi Michaelsen, were collected from a Fijian seagrass meadow. The primary production of their symbiont (Prochloron), the inorganic nitrogen metabolism and the filtration rate were measured to assess the nutritional coupling between the symbiont and the host animal. The loss of organic carbon due to the respiration of D. molle (1.1 �g at. C (mg dry wt)-1 day-1) was greater than that supplied through photosynthesis of the Prochloron (0.69 �g at. C (mg dry wt)-1 day,-1). The carbon supplied through filter-feeding appeared to supplement the ascidian's carbon budget. In contrast, organic carbon from the Prochloron of L. voeltzkowi appeared to meet the colony's respiration needs. The nitrogen budgets of both ascidian colonies were estimated from their respiration rates, the nitrogen requirement of the Prochloron, and the uptake of inorganic nitrogen and particulate organic nitrogen uptake from the water column. The nitrogen incorporated from the surrounding environment could contribute to the net nitrogen gain of the colony. However, our estimate of the nitrogen needed by the Prochloron was much greater than that which could be supplied externally. The amount of nitrogen released by the ascidians was also greater than that which could be supplied externally. This suggests that nitrogen is efficiently recycled within the symbiotic Prochloron-ascidian relationship.

Investigation of the Contribution of Natural Organic Runoff to Dissolved Oxygen Depletion in the Red Deer River

1979 ◽  
Vol 14 (1) ◽  
pp. 71-88
Author(s):  
S.E. Penttinen ◽  
P.H. Bouthillier ◽  
S.E. Hrudey
Keyword(s):  
Dissolved Oxygen ◽  
Red Deer ◽  
Stream Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Experimental Program ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Tributary Stream ◽  
Small Tributary

Abstract Studies on the chronic low dissolved oxygen problems encountered under winter ice in the Red Deer River have generally been unable to account for dissolved oxygen depletion in terms of known manmade inputs. An experimental program was developed to assess the possible nature and approximate bounds of oxygen demand due to natural organic runoff carried to the Red Deer River by a small tributary stream, the Blindman River. The study employed an electrolytic respirometer on stream water samples subjected to prior concentration by vacuum evaporation. Evaluation of carbon and nitrogen budgets in conjunction with the measured oxygen demand indicate that biochemical oxygen demand is originating with natural organic runoff in tributaries of the Red Deer River. The results provide a basis for estimation of the possible contribution to the observed oxygen demand in the Red Deer River originating from natural organic runoff.

scholarly journals Environmental changes during the Paleocene–Eocene Thermal Maximum in Spitsbergen as reflected by benthic foraminifera

2013 ◽  
Vol 32 (1) ◽  
pp. 19737 ◽  
Author(s):  
Jenö Nagy ◽  
David Jargvoll ◽  
Henning Dypvik ◽  
Malte Jochmann ◽  
Lars Riber
Keyword(s):  
Benthic Foraminifera ◽  
Environmental Changes ◽  
Thermal Maximum

Carbon and nitrogen budgets of a winter rapeseed field in Estonia: a methodology for the quantification of all relevant pools and fluxes

2021 ◽  
Author(s):  
Jordi Escuer-Gatius ◽  
Krista Lõhmus ◽  
Merrit Shanskiy ◽  
Karin Kauer ◽  
Hanna Vahter ◽  
...  
Keyword(s):  
Mass Balance ◽  
Environmental Parameters ◽  
Balance Method ◽  
Nitrogen Budgets ◽  
N Cycle ◽  
Carbon And Nitrogen ◽  
Mass Balance Method ◽  
C Cycle ◽  
Winter Rapeseed ◽  
C And N

<p>Agricultural activities can have several adverse impacts on the environment; such as important greenhouse gas (GHG) emissions. To implement effective mitigation measures and create effective policies, it is necessary to know the full carbon and nitrogen budgets of agro-ecosystems. However, very often, information regarding the pools or fluxes involved in the carbon and nitrogen cycles is limited, and essential complementary data needed for a proper interpretation is lacking.</p><p>This study aimed to quantify all the relevant pools and fluxes of a winter rapeseed, a widely spread crop in the Europe and Baltic regions. The N<sub>2</sub>O and CH<sub>4</sub> fluxes were measured weekly using the closed static chamber method from August 2016 to August 2017 in a winter rapeseed field in Central Estonia. Additionally, nutrient leaching and soil chemical parameters, as well as environmental parameters like soil moisture, electrical conductivity and temperature were monitored. At the end of the season, the rapeseed and weed biomasses were collected, weighed and analyzed. The remaining relevant fluxes in the N cycle were calculated using various non-empirical methods: NH<sub>3</sub> volatilization was estimated from slurry and environmental parameters, N deposition and NO<sub>x</sub> emissions were obtained from national reports, and N<sub>2</sub> emissions were calculated with the mass balance method. Regarding the C cycle, gross primary production (GPP) of the rapeseed field was also calculated by the mass balance method. Simultaneously, for comparison and validation purposes, GPP was estimated from the data provided by MOD17A2H v006 series from NASA, and N<sub>2</sub> was estimated from the measured emissions of N<sub>2</sub>O using the N<sub>2</sub>:N<sub>2</sub>O ratio calculated from the DAYCENT model equations.</p><p>N<sub>2</sub> emissions and GPP were the biggest fluxes in the N and C cycles, respectively. N<sub>2</sub> emissions were followed by N extracted with plant biomass in the N cycle, while in the carbon cycle soil and plant respiration and NPP were the highest fluxes after GPP. The carbon balance was positive at the soil level, with a net increase in soil carbon during the period, mainly due to GPP carbon capture. Contrarily, the nitrogen balance resulted in a net loss of N due to the losses related to gaseous emissions (N<sub>2</sub> and N<sub>2</sub>O) and leaching.</p><p>To conclude, it was possible to close the C and N budgets, despite the inherent difficulties of estimating the different C and N environmental pools and fluxes, and the uncertainties deriving from some of the fluxes estimations.</p>

Carbon and Nitrogen Scope for Growth as A Function of Diet in the Sea Scallop Placopecten Magellanicus

1991 ◽  
Vol 71 (2) ◽  
pp. 437-450 ◽  
Author(s):  
Jonathan Grant ◽  
Peter J. Cranford
Keyword(s):  
Nitrogen Content ◽  
Clearance Rate ◽  
Absorption Efficiency ◽  
Placopecten Magellanicus ◽  
Scope For Growth ◽  
Carbon And Nitrogen ◽  
Tissue Weight ◽  
Sea Scallop ◽  
Feeding Experiments ◽  
Carbon And Nitrogen Content

Laboratory feeding experiments with the sea scallop Placopecten magellanicus were carried out to compare scope for growth (SFG) to measured growth and determine the effect of diet on carbon and nitrogen SFG. Diets consisting of cultured phytoplankton, kelp detritus, and resuspended sediment were provided daily for 52 days (October-December). Measurements of clearance rate, absorption efficiency, respiration, O/N ratio, and carbon and nitrogen content of diets and scallop tissue were used to construct carbon and nitrogenbudgets for each diet. Growth coefficients were calculated from change in tissue weight during the study period.

The propagule method as a tool to study assemblage dynamics in benthic foraminifera: An example with pH variations

2021 ◽  
Author(s):  
Anna E. Weinmann ◽  
Susan T. Goldstein ◽  
Maria V. Triantaphyllou ◽  
Martin R. Langer
Keyword(s):  
Shallow Water ◽  
Benthic Foraminifera ◽  
Environmental Changes ◽  
Ph Gradients ◽  
Local Conditions ◽  
Recovery Mechanisms ◽  
Decreasing Ph ◽  
Set Up ◽  
Ph Variations ◽  
Insight Into

<p>Benthic foraminifera are important indicators for ecological studies. The assemblage composition of local communities can be used to analyze influences of environmental variables such as temperature, salinity, pH, and others. In recent years, the experimental propagule method has emerged as an effective tool to evaluate the influence of these variables on assemblage dynamics of benthic foraminifera. Propagules (tiny juveniles) of benthic foraminifera are widespread and can survive outside of a species’ natural distribution range. Their ability to become dormant and be re-activated once local conditions become suitable, is an important driver behind the capacity of foraminiferal assemblages to react quickly to environmental changes. In the laboratory, the propagules are first separated from the coarser fractions by sieving and then cultured under different conditions.</p><p>In the present study, we analyzed the effect of ocean pH on the composition of shallow-water assemblages from Corfu Island (Greece). Like other calcifying organisms, assemblages of foraminifera are susceptible to pH variations and have revealed compositional shifts along natural or experimental pH gradients. Our experimental set-up included four pH treatments between 6.5 and 8.5 at constant temperature and salinity (22°C and 38 ppt) for 5 weeks.</p><p>At the conclusion of the cultivation experiment, we found high numbers of grown specimens (825–1564 per replicate) and a high survivability rate throughout all treatments (78–87%). Higher pH (7.8 and 8.5) resulted in assemblages that were dominated by monothalamous and porcelaneous species, whereas lower pH (6.5 and 7.2) lead to a reduction in porcelaneous and an increase in agglutinated species. Several taxa showed significant positive or negative correlations with decreasing pH values.</p><p>Our results are congruent with previous findings that reported compositional shifts from calcareous to agglutinated taxa with decreasing pH (both from culture and field observations). Our study also indicates that the activation of propagules is an important mechanism behind assemblage dynamics in shallow-water foraminifera. As such, it offers an improved insight into potential resilience and recovery mechanisms of foraminiferal assemblages with regard to local or seasonal pH variations as well as ongoing ocean acidification.</p>

Body size and diet–related morphological variation of bats over the past 65 years in China

2019 ◽  
Vol 101 (1) ◽  
pp. 61-79 ◽  
Author(s):  
Xinke Yue ◽  
Alice C Hughes ◽  
Kyle W Tomlinson ◽  
Shangwen Xia ◽  
Song Li ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Isotope Composition ◽  
Land Use Changes ◽  
Length Change ◽  
Nitrogen Stable Isotope ◽  
Carbon And Nitrogen ◽  
The Past ◽  
Latitudinal Range ◽  
Forearm Length ◽  
Phenotypic Responses

Abstract We examined both historical (1960s) and recent (2017) specimens of an insectivorous bat species (Hipposideros armiger) and a phytophagous bat (Rousettus leschenaultii) from the same latitudinal range to explore phenotypic responses to environmental change in China over the past 65 years. Hipposideros armiger exhibited significant increases in forearm length and three diet-related cranial traits, as well as carbon and nitrogen stable isotope composition, suggesting that modern H. armiger must travel farther for food and may now use different food resources. In contrast, R. leschenaultii showed no change in forearm length but displayed significant increases in diet-related cranial traits. This study provides evidence for differential responses to recent environmental changes in bat species with different diets. The changes in diet-related traits of the two species and the forearm length change on the insectivorous bats suggest that recent phenotypic changes may be adaptions to land-use changes rather than to climate change.

scholarly journals The impact of African aridity on the isotopic signature of Atlantic deep waters across the Middle Pleistocene Transition

2012 ◽  
Vol 77 (1) ◽  
pp. 182-191 ◽  
Author(s):  
Bruno Malaizé ◽  
Elsa Jullien ◽  
Amandine Tisserand ◽  
Charlotte Skonieczny ◽  
E. Francis Grousset ◽  
...  
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Environmental Changes ◽  
Phase Relationship ◽  
Isotopic Signature ◽  
Middle Pleistocene ◽  
Time Interval ◽  
Deep Waters ◽  
Time Period ◽  
The Impact

A high resolution analysis of benthic foraminifera as well as of aeolian terrigenous proxies extracted from a 37 m-long marine core located off the Mauritanian margin spanning the last ~ 1.2 Ma, documents the possible link between major continental environmental changes with a shift in the isotopic signature of deep waters around 1.0–0.9 Ma, within the so-called Mid-Pleistocene Transition (MPT) time period. The increase in the oxygen isotopic composition of deep waters, as seen through the benthic foraminifera δ18O values, is consistent with the growth of larger ice sheets known to have occurred during this transition. Deep-water mass δ13C changes, also estimated from benthic foraminifera, show a strong depletion for the same time interval. This drastic change in δ13C values is concomitant with a worldwide 0.3‰ decrease observed in the major deep oceanic waters for the MPT time period. The phase relationship between aeolian terrigeneous signal increase and this δ13C decrease in our record, as well as in other paleorecords, supports the hypothesis of a global aridification amongst others processes to explain the deep-water masses isotopic signature changes during the MPT. In any case, the isotopic shifts imply major changes in the end-member δ18O and δ13C values of deep waters.

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