scholarly journals Calcification intensity in planktonic Foraminifera reflects ambient conditions irrespective of environmental stress

2013 ◽  
Vol 10 (10) ◽  
pp. 6639-6655 ◽  
Author(s):  
M. F. G. Weinkauf ◽  
T. Moller ◽  
M. C. Koch ◽  
M. Kučera
Keyword(s):  
Surface Water ◽  
Environmental Factors ◽  
Physiological Stress ◽  
Planktonic Foraminifera ◽  
Ambient Conditions ◽  
Shell Weight ◽  
Ambient Seawater ◽  
Ecological Stress ◽  
Water Composition ◽  
Oceanic Carbon

Abstract. Planktonic Foraminifera are important marine calcifiers, and the ongoing change in the oceanic carbon system makes it essential to understand the influence of environmental factors on the biomineralization of their shells. The amount of calcite deposited by planktonic Foraminifera during calcification has been hypothesized to reflect a range of environmental factors. However, it has never been assessed whether their calcification only passively responds to the conditions of the ambient seawater or whether it reflects changes in resource allocation due to physiological stress. To disentangle these two end-member scenarios, an experiment is required where the two processes are separated. A natural analogue to such an experiment occurred during the deposition of the Mediterranean sapropels, where large changes in surface water composition and stratification at the onset of the sapropel deposition were decoupled from local extinctions of planktonic Foraminifera species. We took advantage of this natural experiment and investigated the reaction of calcification intensity, expressed as mean area density (MAD), of four species of planktonic Foraminifera to changing conditions during the onset of Sapropel S5 (126–121 ka) in a sediment core from the Levantine Basin. We observed a significant relationship between MAD and surface water properties, as reflected by stable isotopes in the calcite of Foraminifera shells, but we failed to observe any reaction of calcification intensity on ecological stress during times of decreasing abundance culminating in local extinction. The reaction of calcification intensity to surface water perturbation at the onset of the sapropel was observed only in surface-dwelling species, but all species calcified more strongly prior to the sapropel deposition and less strongly within the sapropel than at similar conditions during the present-day. These results indicate that the high-salinity environment of the glacial Mediterranean Sea prior to sapropel deposition induced a~more intense calcification, whereas the freshwater injection to the surface waters associated with sapropel deposition inhibited calcification. The results are robust to changes in carbonate preservation and collectively imply that changes in normalized shell weight in planktonic Foraminifera should reflect mainly abiotic forcing.

scholarly journals Calcification intensity in planktonic Foraminifera reflects ambient conditions irrespective of environmental stress

2013 ◽  
Vol 10 (7) ◽  
pp. 11213-11253
Author(s):  
M. F. G. Weinkauf ◽  
T. Moller ◽  
M. C. Koch ◽  
M. Kučera
Keyword(s):  
Surface Water ◽  
Environmental Factors ◽  
Physiological Stress ◽  
Planktonic Foraminifera ◽  
Ambient Conditions ◽  
Shell Weight ◽  
Ambient Seawater ◽  
Ecological Stress ◽  
Water Composition ◽  
Oceanic Carbon

Abstract. Planktonic Foraminifera are important marine calcifiers, and the ongoing change in the oceanic carbon system makes it essential to understand the influence of environmental factors on the biomineralisation of their shells. The amount of calcite deposited by planktonic Foraminifera during calcification has been hypothesized to reflect a range of environmental factors. However, it has never been assessed whether their calcification only passively responds to the conditions of the ambient seawater or whether it reflects changes in resource allocation due to physiological stress. To disentangle these two end-member scenarios, an experiment is required where the two processes are separated. A natural analogue to such an experiment occurred during the deposition of the Mediterranean sapropels, where large changes in surface water composition and stratification at the onset of the sapropel deposition were decoupled from local extinctions of planktonic Foraminifera species. We take advantage of this natural experiment and investigate the reaction of calcification intensity, expressed as size-normalized weight (SNW), of four species of planktonic Foraminifera to changing conditions during the onset of Sapropel S5 (126–121 ka) in a sediment core from the Levantine Basin. We observe a significant relationship between SNW and surface water properties, as reflected by stable isotopes in the calcite of Foraminifera shells, but we failed to observe any reaction of calcification intensity on ecological stress during times of decreasing abundance culminating in local extinction. The reaction of calcification intensity to surface water perturbation at the onset of the sapropel was observed only in surface dwelling species, but all species calcified more strongly prior to the sapropel deposition and less strongly within the sapropel than at comparable conditions during the present day. These results indicate that the high-salinity environment of the glacial Mediterranean Sea prior to sapropel deposition induced a more intense calcification, whereas the freshwater injection to the surface waters associated with sapropel deposition inhibited calcification. The results are robust to changes in carbonate preservation and collectively imply that changes in normalized shell weight in planktonic Foraminifera should reflect mainly abiotic forcing.

scholarly journals Impact of seawater <i>p</i>CO<sub>2</sub> on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with <i>Ammonia tepida</i>

2010 ◽  
Vol 7 (1) ◽  
pp. 81-93 ◽  
Author(s):  
D. Dissard ◽  
G. Nehrke ◽  
G. J. Reichart ◽  
J. Bijma
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Benthic Foraminifera ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Planktonic Foraminifera ◽  
Ambient Conditions ◽  
Precipitated Calcium Carbonate ◽  
Shell Weight ◽  
Dissolved Carbon

Abstract. Evidence of increasing concentrations of dissolved carbon dioxide, especially in the surface ocean and its associated impacts on calcifying organisms, is accumulating. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium carbonate. Hence, their response to an acidifying ocean may have important consequences for future inorganic carbon cycling. To assess the sensitivity of benthic foraminifera to changing carbon dioxide levels and subsequent alteration in seawater carbonate chemistry, we cultured specimens of the shallow water species Ammonia tepida at two concentrations of atmospheric CO2 (230 and 1900 ppmv) and two temperatures (10 °C and 15 °C). Shell weights and elemental compositions were determined. Impact of high and low pCO2 on elemental composition are compared with results of a previous experiment were specimens were grown under ambient conditions (380 ppvm, no shell weight measurements of specimen grown under ambient conditions are, however, available). Results indicate that shell weights decrease with decreasing [CO32−], although calcification was observed even in the presence of calcium carbonate under-saturation, and also decrease with increasing temperature. Thus both warming and ocean acidification may act to decrease shell weights in the future. Changes in [CO32−] or total dissolved inorganic carbon do not affect the Mg distribution coefficient. On the contrary, Sr incorporation is enhanced under increasing [CO32−]. Implications of these results for the paleoceanographic application of foraminifera are discussed.

scholarly journals Environmental Factors Causing Stress in Avicennia marina Mangrove in Rabigh Lagoon Along the Red Sea: Based on a Multi-Approach Study

2021 ◽  
Vol 8 ◽  
Author(s):  
Mohammed O. Aljahdali ◽  
Abdullahi B. Alhassan ◽  
Zhaohui Zhang
Keyword(s):  
Surface Water ◽  
Environmental Factors ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Red Sea ◽  
Nutrient Dynamics ◽  
High Salinity ◽  
Physiological Stress ◽  
High Surface ◽  
Nutrient Level

Lagoons along the Red Sea are socio-economically important but most vulnerable ecosystems. Strong evaporation, strengthened due to global warming, leads to high salinity and high temperature in surface water, which exacerbate physiological stress in mangroves. Rabigh Lagoon is characterized by unusually large spatial differences in nutrient dynamics and physicochemical parameters. We conducted a multi-approach study to demonstrate how environmental factors cause growth retardation and stress in mangroves. There were significant variations (P &lt; 0.05) in water salinities and temperatures, nitrogen and phosphorus abundance in sediments, and antioxidants in mangroves among 8 sites across the lagoon. Salinity and water temperature rapidly increased from the northern where Red Sea seawater enters to the southern end, but dissolved oxygen declined. High salinity (44.9), high surface water temperature (28.8°C) and relatively high nutrients at the southern end of the lagoon (S8) corresponded to high concentrations of antioxidants. High δ13C (−12.4‰) and δ15N (4.9‰) in the sediments at S8 also reveal relatively high nutrient level due to stagnant water, camel grazing, and runoff bringing in fertilizer from agriculture activities in the catchments during seasonal flooding events. Principal component analyses showed that N and P limitation at the lagoon entrance is the leading cause for mangrove stress, while high salinity, temperature, and low dissolved oxygen are the predominant factors for high antioxidants concentrations at the southern end of the lagoon.

scholarly journals Disruption of the Atlantic Meridional Circulation during Deglacial Climates Inferred from Planktonic Foraminiferal Shell Weights

2021 ◽  
Vol 9 (5) ◽  
pp. 519
Author(s):  
Stergios D. Zarkogiannis
Keyword(s):  
Atlantic Ocean ◽  
Meridional Circulation ◽  
Order Approximation ◽  
Planktonic Foraminifera ◽  
Sediment Cores ◽  
Meridional Overturning Circulation ◽  
Density Structure ◽  
Last Interglacial ◽  
Shell Weight ◽  
The North

Changes in the density structure of the upper oceanic water masses are an important forcing of changes in the Atlantic Meridional Overturning Circulation (AMOC), which is believed to widely affect Earth’s climate. However, very little is known about past changes in the density structure of the Atlantic Ocean, despite being extensively studied. The physical controls on planktonic foraminifera calcification are explored here, to obtain a first-order approximation of the horizontal density gradient in the eastern Atlantic during the last 200,000 years. Published records of Globigerina bulloides shells from the North and Tropical eastern Atlantic were complemented by the analysis of a South Atlantic core. The masses of the same species shells from three different dissolution assessed sediment cores along the eastern Atlantic Ocean were converted to seawater density values using a calibration equation. Foraminifera, as planktonic organisms, are subject to the physical properties of the seawater and thus their shells are sensitive to buoyancy forcing through surface temperature and salinity perturbations. By using planktonic foraminifera shell weight as an upper ocean density proxy, two intervals of convergence of the shell masses are identified during cold intervals of the last two deglaciations that may be interpreted as weak ocean density gradients, indicating nearly or completely eliminated meridional circulation, while interhemispheric Atlantic density differences appear to alleviate with the onset of the last interglacial. The results confirm the significance of variations in the density of Atlantic surface waters for meridional circulation changes.

scholarly journals Influence of Selected Coagulants of Indicator and Dioxin-Like PCB Removal from Drinking Water

2017 ◽  
Vol 24 (1) ◽  
pp. 41-51
Author(s):  
Agata Rosińska
Keyword(s):  
Surface Water ◽  
Total Concentration ◽  
Sulfate Removal ◽  
Aluminium Sulfate ◽  
Water Composition ◽  
Pcb 126 ◽  
Reduction Efficiency ◽  
Water Rate ◽  
Trade Names ◽  
Dioxin Like Pcb

Abstract The aim of the research was to compare selected coagulants efficiency in indicator and chosen dioxin-like PCB removal from surface water. As coagulants, there were used aluminium sulfate and 5 hydrolyzed polyaluminium chlorides, with trade names: PAX-XL1, PAX-XL10, PAX-XL19, PAX-XL60, PAX-XL69. For the research, surface water was used, collected from dam reservoir. The water composition was modified with standard mixtures PCB MIX24 and MIX13, in order to obtain concentration of each congener equal to 300 ng/dm3. The PCB MIX24 mixture was composed of indicator congeners solution: 28, 52, 101, 118, 138, 153, and 180, whereas the MIX13 mixture - solution of three dioxin-like PCB 77, PCB 126, and PCB 169. It was demonstrated that the application of aluminium sulfate allowed for reaching better effects for purifying water of PCB, than with the usage of pre-hydrolyzed salts, polyaluminium chlorides. Out of the studied coagulants, the best effects for indicator PCB removal were obtained with the application of aluminium sulfate, total PCB concentration was decreased by 65%. The highest efficiency for indicator congeners removal (90%) was obtained for PCB 138 and 153. After the application of hydrolyzed polyaluminium chlorides PAX-XL1, PAX-XL10 decrease in higher chlorinated PCB concentration was obtained, in the range of 23 to 74%. Selectivity of chosen PCB congener removal, depending on applied coagulant, was demonstrated; with the usage of aluminium sulfate, removal of heptachlorobiphenyl PCB 180 at the level of 34% was obtained, whereas with the application of PAX-XL1 and PAX-XL10 higher reduction efficiency for this congener was obtained, i.e. 83 and 74% respectively. For dioxin-like PCB, after application of aluminium sulfate, total concentration reduction by 74% was obtained, efficiency of this congeners removal amounted to from 54 (PCB 77) up to 72% (PCB 126), similar results were obtained after the usage of PAX-XL1. The lowest PCB removal from water rate was stated for coagulants PAX-XL60 and PAX-XL69.

scholarly journals Development of passive sampler POCIS for the analysis of polar pesticides in surface water

2015 ◽  
Vol 18 (2) ◽  
pp. 132-144
Author(s):  
Trang Thi Nhu Tran ◽  
Ty Thi Pham ◽  
Hai Lam Son Truong
Keyword(s):  
Surface Water ◽  
Environmental Factors ◽  
Pesticide Residues ◽  
Passive Sampling ◽  
Sampling Method ◽  
Passive Sampler ◽  
Polar Pesticides ◽  
Sampling Process ◽  
European Standards ◽  
First Time

The first time in Vietnam a passive sampling method has been developed to analyse the polar pesticides in surface water. The initial investigations of POCIS were performed for 7 polar pesticides as simazine,thiodicarb, carbofuran, chlortoluron, atrazine, isoproturon, and diuron. We determined the sampling rates RS for these substances ranged from 0.369 to 0.962 L day- 1. The obtained values of ku and RS showed the important influence of environmental factors such as flow on the ability to integrate polar pesticides in passive sampling process. This method can be applied to determine these 7 polar pesticides in surface water at trace levels according to European standards for pesticide residues in water (< 0.1 μg L-1).

scholarly journals Key Environmental Factors Controlling Planktonic Foraminiferal and Pteropod Community’s Response to Late Quaternary Hydroclimate Changes in the South Aegean Sea (Eastern Mediterranean)

2020 ◽  
Vol 8 (9) ◽  
pp. 709
Author(s):  
Christina Giamali ◽  
George Kontakiotis ◽  
Efterpi Koskeridou ◽  
Chryssanthi Ioakim ◽  
Assimina Antonarakou
Keyword(s):  
Environmental Factors ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Explanatory Power ◽  
Principal Component ◽  
Aegean Sea ◽  
Late Glacial ◽  
The South

A multidisciplinary study was conducted in order to investigate the environmental factors affecting the planktonic foraminiferal and pteropod communities of the south Aegean Sea. Aspects of the Late Quaternary paleoceanographic evolution were revealed by means of quantitative analyses of planktonic foraminiferal and pteropod assemblages (including multivariate statistical approach; principal component analysis (PCA)), the oxygen (δ18O) and carbon (δ13C) isotopic composition of planktonic foraminifera and related paleoceanographic (planktonic paleoclimatic curve (PPC), productivity (E-index), stratification (S-index), seasonality) indices, extracted by the gravity core KIM-2A derived from the submarine area between Kimolos and Sifnos islands. Focusing on the last ~21 calibrated thousands of years before present (ka BP), cold and eutrophicated conditions were identified during the Late Glacial period (21.1–15.7 ka BP) and were followed by warmer and wetter conditions during the deglaciation phase. The beginning of the Holocene was marked by a climatic amelioration and increased seasonality. The more pronounced environmental changes were identified during the deposition of the sapropel sublayers S1a (9.4–7.7 ka BP) and S1b (6.9–6.4 ka BP), with extremely warm and stratified conditions. Pteropod fauna during the sapropel deposition were recorded for the first time in the south Aegean Sea, suggesting arid conditions towards the end of S1a. Besides sea surface temperature (SST), which shows the highest explanatory power for the distribution of the analyzed fauna, water column stratification, primary productivity, and seasonality also control their communities during the Late Quaternary.

scholarly journals Spatial Differences in the Chemical Composition of Surface Water in the Hornsund Fjord Area: A Statistical Analysis with A Focus on Local Pollution Sources

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 496
Author(s):  
Krystyna Koziol ◽  
Marek Ruman ◽  
Filip Pawlak ◽  
Stanisław Chmiel ◽  
Żaneta Polkowska
Keyword(s):  
Chemical Composition ◽  
Surface Water ◽  
Human Activity ◽  
Principal Component ◽  
Inverse Correlation ◽  
Published Data ◽  
Pollution Transport ◽  
Local Pollution ◽  
Water Composition ◽  
Spatial Differences

Surface catchments in Svalbard are sensitive to external pollution, and yet what is frequently considered external contamination may originate from local sources and natural processes. In this work, we analyze the chemical composition of surface waters in the catchments surrounding the Polish Polar Station in Svalbard, Hornsund fjord area. We have pooled unpublished and already published data describing surface water composition in 2010, related to its pH, electrical conductivity (EC), metals and metalloids, total organic carbon (TOC) and selected organic compound concentrations, including persistent organic pollutants (POPs) and surfactants. These data were statistically analyzed for spatial differences, using Kruskal–Wallis ANOVA and principal component analysis (PCA), with distance from the station in the PCA approximating local human activity impact. The geological composition of the substratum was found to be a strong determinant of metal and metalloid concentrations, sufficient to explain significant differences between the studied water bodies, except for the concentration of Cr. The past and present human activity in the area may have contributed also to some of the polycyclic aromatic hydrocarbons (PAHs), although only in the case of naphthalene can such an effect be confirmed by an inverse correlation with distance from the station. Other likely factors contributing to the chemical concentrations in the local waters are marine influence, long-range pollution transport and release from past deposition in the environment.

Effect of multicomponent fouling during microfiltration of natural surface waters containing nC60 fullerene nanoparticles

2017 ◽  
Vol 3 (4) ◽  
pp. 744-756 ◽  
Author(s):  
R. Floris ◽  
G. Moser ◽  
K. Nijmeijer ◽  
E. R. Cornelissen
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Surface Waters ◽  
Membrane Fouling ◽  
Industrial Water ◽  
Water Composition ◽  
Water Treatment Plants ◽  
Fullerene Nanoparticles ◽  
Microfiltration Membranes

To understand and mitigate the role of surface water composition and associated membrane fouling in the removal of nC60 nanoparticles by low-pressure membranes, experiments were carried out with microfiltration membranes using natural feed waters, mimicking separation in real industrial water treatment plants.

scholarly journals The impact of anthropogenic and environmental factors on the variability of Escherichia coli in rivers in southwest Bangladesh

2021 ◽  
Author(s):  
M. M. Majedul Islam ◽  
Md. Atikul Islam
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Surface Water ◽  
Environmental Factors ◽  
Physicochemical Parameters ◽  
Sewage Treatment Plant ◽  
Oxygen Demand ◽  
Faecal Contamination ◽  
E Coli ◽  
The Impact

Abstract Faecal contamination of surface water sources is an important water quality issue worldwide. Although quite a few studies exist on surface water faecal contamination and variability of indicator bacteria, most of the studies have been based on larger river basins and in temperate region. The variability is relatively unknown in local scale and in tropical developing countries. In this study we assess how anthropogenic and environmental factors affect faecal contamination and physicochemical parameters in Rupsha and Bhairab rivers around Khulna city, Bangladesh. Water samples were collected from six locations of the rivers during a wet and dry period in 2018 to measure Escherichia coli (E. coli) concentrations. Water physicochemical parameters—temperature, turbidity, pH, dissolved oxygen, biochemical oxygen demand and chemical oxygen demand were also measured. Higher concentrations of E. coli were found in the sampling sites located near the densely populated urban area compared to the downstream site, which receives fewer amounts of discharges from sewer drains. All the E. coli samples violated bathing water quality standards. E. coli concentrations were found to be correlated positively with precipitation and turbidity. A linear regression model was applied, that explains large part of the variation in E. coli concentration (R2 = 0.42). Water quality index assessment was also ranked the water quality as ‘poor’ category; indicate that the water is unsuitable for uses in domestic and recreational purposes and high health risks involved with the water use. The study findings highlight the problem of untreated sewage discharge into the rivers. Implementation of sewage treatment plant with adequate capacity is highly recommended.

Sign in / Sign up

Export Citation Format

Share Document