scholarly journals Mercury Accumulation and Elimination in Different Tissues of Zebrafish (Danio rerio) Exposed to a Mercury-Supplemented Diet

2021 ◽  
Vol 9 (8) ◽  
pp. 882
Author(s):  
Hugo C. Vieira ◽  
Andreia C. M. Rodrigues ◽  
Amadeu M. V. M. Soares ◽  
Sizenando Abreu ◽  
Fernando Morgado
Keyword(s):  
Water Column ◽  
Danio Rerio ◽  
Accumulation Rate ◽  
Exposure Period ◽  
Mercury Content ◽  
Mercury Accumulation ◽  
Contaminated Food ◽  
Different Tissues ◽  
Model Fish ◽  
Hg Accumulation

In this study, we evaluated the bioaccumulation of mercury in zebrafish (Danio rerio) exposed to mercury-contaminated food for 21 days and the depuration of mercury for a subsequent post-exposure period of 28 days. Four tissues (muscle, liver, gills, and skin) were analyzed for mercury content. Overall, data indicated that Hg accumulation in the liver is faster than in other tissues. Furthermore, the liver is the tissue with the highest accumulation rate per day (0.021 µg Hg g−1 day−1), followed by muscle, skin, and gills. Conversely, the Hg depuration rates in different tissues showed the following order: gills > skin > muscle > liver. The bioaccumulation factor values of liver and muscle increased linearly during the uptake period. The ratios between mercury concentration in liver and muscle during the experiment also increased during the uptake period and remained higher than 1 during the elimination period, suggesting that Danio rerio needed more than 4 weeks of depuration. Finally, the distribution of Hg in the water column during the accumulation period is Hg particulate > Hg dissolved, and during the depuration period it is the opposite, mercury particulate < mercury dissolved. In conclusion, this study contributes to a better understanding of the differences in Hg dynamics during the accumulation and depuration stages in a model fish, also emphasizing the alterations on Hg available in the water column.

Ingestion of metal-nanoparticle contaminated food disrupts endogenous microbiota in zebrafish (Danio rerio)

2013 ◽  
Vol 174 ◽  
pp. 157-163 ◽  
Author(s):  
Daniel L. Merrifield ◽  
Benjamin J. Shaw ◽  
Glenn M. Harper ◽  
Imad P. Saoud ◽  
Simon J. Davies ◽  
...  
Keyword(s):  
Danio Rerio ◽  
Metal Nanoparticle ◽  
Contaminated Food

scholarly journals Control of the geomorphology and gas hydrate extent on widespread gas emissions offshore Romania

2017 ◽  
Vol 188 (4) ◽  
pp. 26 ◽  
Author(s):  
Vincent Riboulot ◽  
Antonio Cattaneo ◽  
Carla Scalabrin ◽  
Arnaud Gaillot ◽  
Gwénaël Jouet ◽  
...  
Keyword(s):  
Water Column ◽  
Black Sea ◽  
Gas Hydrate ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
The Black Sea ◽  
North East ◽  
Bottom Simulating Reflectors ◽  
Gas Flares ◽  
Sea Fan

The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediments offshore the Danube delta is rich in gas and thus shows Bottom Simulating Reflectors (BSR). The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a geomorphological analysis of the continental slope north-east of the Danube canyon compared with the spatial distribution of gas seeps in the water column and the predicted extent of the gas hydrate stability zone. This analysis provides new evidence of the role of geomorphological setting and gas hydrate extent in controlling the location of the observed gas expulsions and gas flares in the water column. Gas flares are today considered an important source of the carbon budget of the oceans and, potentially, of the atmosphere.

scholarly journals Effects of eutrophication on sedimentary organic carbon cycling in five temperate lakes

2019 ◽  
Vol 16 (19) ◽  
pp. 3725-3746 ◽  
Author(s):  
Annika Fiskal ◽  
Longhui Deng ◽  
Anja Michel ◽  
Philip Eickenbusch ◽  
Xingguo Han ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Trophic State ◽  
Microbial Respiration ◽  
Accumulation Rate ◽  
Eutrophic Lake ◽  
Accumulation Rates ◽  
Artificial Lake ◽  
Eutrophic Lakes ◽  
Lake Ecosystems

Abstract. Even though human-induced eutrophication has severely impacted temperate lake ecosystems over the last centuries, the effects on total organic carbon (TOC) burial and mineralization are not well understood. We study these effects based on sedimentary records from the last 180 years in five Swiss lakes that differ in trophic state. We compare changes in TOC content and modeled TOC accumulation rates through time to historical data on algae blooms, water column anoxia, wastewater treatment, artificial lake ventilation, and water column phosphorus (P) concentrations. We furthermore investigate the effects of eutrophication on rates of microbial TOC mineralization and vertical distributions of microbial respiration reactions in sediments. Our results indicate that the history of eutrophication is well recorded in the sedimentary record. Overall, eutrophic lakes have higher TOC burial and accumulation rates, and subsurface peaks in TOC coincide with past periods of elevated P concentrations in lake water. Sediments of eutrophic lakes, moreover, have higher rates of total respiration and higher contributions of methanogenesis to total respiration. However, we found strong overlaps in the distributions of respiration reactions involving different electron acceptors in all lakes regardless of lake trophic state. Moreover, even though water column P concentrations have been reduced by ∼ 50 %–90 % since the period of peak eutrophication in the 1970s, TOC burial and accumulation rates have only decreased significantly, by ∼ 20 % and 25 %, in two of the five lakes. Hereby there is no clear relationship between the magnitude of the P concentration decrease and the change in TOC burial and accumulation rate. Instead, data from one eutrophic lake suggest that artificial ventilation, which has been used to prevent water column anoxia in this lake for 35 years, may help sustain high rates of TOC burial and accumulation in sediments despite water column P concentrations being strongly reduced. Our study provides novel insights into the influence of human activities in lakes and lake watersheds on lake sediments as carbon sinks and habitats for diverse microbial respiration processes.

scholarly journals Toxicity of sodium fluoride (NaF) to juvenile catfish, Clarias batrachus

2013 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
Shafina Shawon Sharmin ◽  
Md Baki Billah ◽  
Md Kawser Ahmed ◽  
Md Abdus Salam
Keyword(s):  
Sodium Fluoride ◽  
Chronic Exposure ◽  
Lethal Dose ◽  
Exposure Period ◽  
Degenerative Changes ◽  
Clarias Batrachus ◽  
Cellular Infiltration ◽  
Internal Organs ◽  
Abnormal Behaviors ◽  
Different Tissues

Effects of sodium fluoride (NaF) on Clarias batrachus in the aquarium at a sub lethal dose of 0, 15, 30, 40, 50 and 60 mg/l for a chronic exposure period of 120 days were evaluated. The histopathological alterations in different tissues from brain, gill and liver were examined in fishes showed abnormal behaviors. Such as rupture of hepatocytes, congestion, necrosis pyknosis, cellular infiltration, and degenerative changes. In case of liver, individualization of hepetocytes, mild necrosis, vacuolation, pyknosis and hemorrhage were observed. These results suggest that NaF affects severely on the tissues of the internal organs leading to threat of life and survival. Dhaka Univ. J. Biol. Sci. 22(1): 1-7, 2013 (January)

scholarly journals Isotopically Light Cd in Sediments Underlying Oxygen Deficient Zones

2021 ◽  
Vol 9 ◽  
Author(s):  
Lena Chen ◽  
Susan H. Little ◽  
Katharina Kreissig ◽  
Silke Severmann ◽  
James McManus
Keyword(s):  
Water Column ◽  
Continental Margin ◽  
Solid Phase ◽  
Isotope Composition ◽  
Accumulation Rate ◽  
Cadmium Sulphide ◽  
Crustal Material ◽  
Deep Seawater ◽  
Complex Particle ◽  
Cd Isotopes

Cadmium is a trace metal of interest in the ocean partly because its concentration mimics that of phosphate. However, deviations from the global mean dissolved Cd/PO4 relationship are present in oxygen deficient zones, where Cd is depleted relative to phosphate. This decoupling has been suggested to result from cadmium sulphide (CdS) precipitation in reducing microenvironments within sinking organic matter. We present Cd concentrations and Cd isotope compositions in organic-rich sediments deposited at several upwelling sites along the northeast Pacific continental margin. These sediments all have enriched Cd concentrations relative to crustal material. We calculate a net accumulation rate of Cd in margin settings of between 2.6 to 12.0 × 107 mol/yr, higher than previous estimates, but at the low end of a recently published estimate for the magnitude of the marine sink due to water column CdS precipitation. Cadmium in organic-rich sediments is isotopically light (δ114/110CdNIST-3108 = +0.02 ± 0.14‰, n = 26; 2 SD) compared to deep seawater (+0.3 ± 0.1‰). However, isotope fractionation during diagenesis in continental margin settings appears to be small. Therefore, the light Cd isotope composition of organic-rich sediments is likely to reflect an isotopically light source of Cd. Non-quantitative biological uptake of light Cd by phytoplankton is one possible means of supplying light Cd to the sediment, which would imply that Cd isotopes could be used as a tracer of past ocean productivity. However, water column CdS precipitation is also predicted to preferentially sequester light Cd isotopes from the water column, which could obfuscate Cd as a tracer. We also observe notably light Cd isotope compositions associated with elevated solid phase Fe concentrations, suggesting that scavenging of Cd by Fe oxide phases may contribute to the light Cd isotope composition of sediments. These multiple possible sources of isotopically light Cd to sediments, along with evidence for complex particle cycling of Cd in the water column, bring into question the straightforward application of Cd isotopes as a paleoproductivity proxy.

Distribution of Phenylalanine Ammoma-Lyase and 4-Coumarate: CoA Ligase in Oat Primary Leaf Tissues

1981 ◽  
Vol 36 (5-6) ◽  
pp. 389-395 ◽  
Author(s):  
Wolfgang Knogge ◽  
Christa Beulen ◽  
Gottfried Weissenböck
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Direct Evidence ◽  
Accumulation Rate ◽  
Pal Activity ◽  
Coa Ligase ◽  
Vascular Elements ◽  
Intact Chloroplasts ◽  
Plant Stage ◽  
Leaf Tissues ◽  
Different Tissues

Abstract 4-Coumarate: CoA ligase (CL) isolated from oat primary leaves shows two activity maxim a in 5 and 7 day old seedlings, the first of which corresponds with the highest flavone accumulation rate. In this plant stage most of L-phenylalanine ammonia-lyase (PAL) is located in the epidermal tissues, whereas CL dominates in mesophyll protoplasts and in the vascular elements. In the older leaves, in which PAL is only detectable in the epiderm is and in vascular elements, most of CL is located in the latter. The CL from different tissues varies significantly in substrate specificity. Investigations of intact chloroplasts from isolated protoplasts revealed that approximately half of the PAL activity can be extracted from this organelle, whereas there is no direct evidence for the existence of CL in plastids.

Turbidity, particle fluxes and mineralisation of carbon and nitrogen in a shallow coastal area

1995 ◽  
Vol 46 (1) ◽  
pp. 409 ◽  
Author(s):  
JR Valeur ◽  
A Jensen ◽  
M Pejrup
Keyword(s):  
Water Column ◽  
Deposition Rate ◽  
Time Resolution ◽  
Coastal Area ◽  
Accumulation Rate ◽  
Mixing Layer ◽  
Particulate Nitrogen ◽  
Indirect Measure ◽  
Particle Fluxes ◽  
Shallow Coastal Area

During a research programme carried out in a shallow coastal area (�rhus Bight, Denmark), short-term and long-term particle dynamics were measured continuously for a year in the water column and in the seabed. The research area is a homogeneous accumulation area for fine-grained sediment, with a water depth of 15 m. Fluxes in the water column were measured at nine depths with a time resolution of one to two weeks during one year, using duplicate sediment traps with an aspect ratio of 5. Significant correlation between turbidity and vertical particle fluxes was found. Continuous measurements close to the bottom gave an indirect measure of the concentration of suspended particles every 5 min. In this way, it was possible to measure resuspension dynamics with a detailed time resolution. A new method was developed for the separation of downward fluxes of primary and secondary (resuspended) sediment. The net deposition rate of total particulate matter (TPM) found by this method (DTPM = 1050 g m-2 year-1) is in good agreement with the accumulation rate found by 210Pb core datings (ATPM = 890 g m-2 year-1). The accumulation rate of particulate organic carbon (POC) and total particulate nitrogen (TPN) beneath the benthic mixing layer was five times smaller than the net deposition rate; this is assumed to be caused by mineralization mainly in the benthic mixing layer. Resuspension events are believed to play a major role in mineralization of organic matter and exchange of nutrients with the water column. Resuspension rates were 10 to 100 times greater than the net deposition rates in all measuring periods. Supply of new, easily resuspendable sediment during the spring phytoplankton bloom dramatically increased the possibility of resuspension.

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