Variations of dissolved oxygen concentrations under influence of seasonal stratification using deep-water observations in the southern region of the Caspian Sea

Jamshidi, Siamak

doi:10.1007/s12517-022-10705-2

Cited by 3 publications

(4 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The phylogenetic tree was constructed using 122 archaeal proteins. Reference genomes and subclades refer to previous study ( 20 ). MAGs newly reconstructed in this study are marked with white circles.…”

Section: Resultsmentioning

confidence: 99%

“…Different from MGI and MGIV, which are deep sea organisms ( 13 , 15 ), MGII is widely distributed in global seawater ( 16 ) and have a higher abundance in the surface layer than in the deep sea ( 17 , 18 ). The DO concentration could decrease from 4 mg/L to 9 mg/L in surface layer (0–200 m) to 1 ~ 2 mg/L in deeper layers (>200 m) at different sea areas ( 19 – 21 ), which means that MGII is at a higher risk of oxygen exposure. Metagenomic data has revealed that MGII are aerobic heterotrophs particularly capable of decomposing proteins, fatty acids, and polysaccharides ( 22 – 24 ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Oxygen-driven divergence of marine group II archaea reflected by transitions of superoxide dismutases

Qu,

Li,

Gong

et al. 2024

Microbiol Spectr

View full text Add to dashboard Cite

The superoxide anion radical (O 2•− ), the primary reactive oxygen species (ROS), is detrimental to cellular functions. Marine group II (MGII) archaea predominantly inhabit surface ocean environments that are rich in ROS; however, their defense mechanisms against ROS damage remain unknown. In this study, we integrated the analyses of archaeal 16S rRNA gene amplicons and metagenome-assemblage genomes of MGII archaea from the northern South China Sea and 250 other previously published MGII genomes to investigate their antioxidant mechanisms. The results show that the proportion of oxygen-promoted MGII operational taxonomic units in the iron/manganese superoxide dismutase (Fe/MnSOD) gene-containing group was significantly higher than that in the nickel SOD (NiSOD) group, suggesting that MGII members with Fe/MnSOD may have superior antioxidant capacity relative to members possessing NiSOD. Molecular clock analysis of MGII genomes revealed frequent species divergence correlating to the differentiation of Fe/MnSOD or NiSOD genes. The acquisition/loss of these genes in the MGII genomes was synchronized with the historical changes in atmospheric oxygen and oceanic metal element concentrations over the last 2.4 billion years, suggesting that variations in the antioxidant capacity of MGII archaea in response to changing oxygen levels may have driven their divergences over time. IMPORTANCE Reactive oxygen species (ROS), including superoxide anion, is a series of substances that cause oxidative stress for all organisms. Marine group II (MGII) archaea are mainly live in the surface seawater and exposed to considerable ROS. Therefore, it is important to understand the antioxidant capacity of MGII. Our research found that Fe/Mn- superoxide dismutase (Fe/MnSOD) may be more suitable for MGII to resist oxidative damage, and the changes in oxygen concentrations and SOD metallic cofactors play an important role in the selection of SOD by the 17 clades of MGII, which in turn affects the species differentiation of MGII. Overall, this study provides insight into the co-evolutionary history of these uncultivated marine archaea with the earth system.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oxygen-driven divergence of marine group II archaea reflected by transitions of superoxide dismutases

Qu,

Li,

Gong

et al. 2024

Microbiol Spectr

View full text Add to dashboard Cite

show abstract

“…Although the influence of freshwater input in the mouth of rivers is considerable on the stratification pattern (Kosarev, 2005;Tuzhilkin and Kosarev, 2005;Zaker et al, 2007). Observations and vertical temperature profiles showed existence of a strong seasonal thermal stratification in the region (Figure 7; Jamshidi and Yousefi, 2021;Jamshidi, 2022). Significant changes (thermocline and pycnocline layers) were mainly observed across the upper and intermediate layers.…”

Section: Data Availability Statementmentioning

confidence: 93%

“…Due to the low vertical changes in water salinity (the range of seawater salinity between 12-13 psu, Figures 12A-D, 13A, B), the vertical changes in seawater density were correlated with vertical changes in seawater temperature (Jamshidi and Bakar, 2012). The deep-water layer is located under the thermocline layer with low seasonal changes in temperature and salinity (Tuzhilkin and Kosarev, 2005;Jamshidi, 2022). The results of measurements of physical properties such as temperature, salinity, and sigma-T are presented in Figure 12A-D.…”

Section: Hydrophysical Studiesmentioning

confidence: 99%

Flow measurement in the southern coast of the Caspian Sea

Jamshidi

2024

Front. Mar. Sci.

Self Cite

View full text Add to dashboard Cite

Oceanographic monitoring was conducted in the southern basin of the Caspian Sea to evaluate the physical structure of seawater and sea currents. This monitoring aimed to gather data and analyze the characteristics of the seawater, including temperature, salinity, density, and other relevant parameters. Additionally, the monitoring also focused on studying the patterns and dynamics of sea currents in the region. The collected data and analysis from this monitoring period provided valuable insights into the oceanographic conditions of the southern basin of the Caspian Sea. During storm events, a high level of correlation between the current and wind data was observed in the southern basin of the Caspian Sea during the 2017-2018 monitoring period. The measured current data indicated that the predominant directions were north (N) and northwest (NW). It was observed that strong gusts predominantly originated from the north (N) and northwest (NW) directions. Additionally, a smaller portion of the strong gusts was observed to come from the South-Southeast (S-SE) direction. These findings indicate that the prevailing wind patterns during the monitoring period were primarily from the north and northwest, with a lesser contribution from the South-Southeast direction. The current profiles observed during the monitoring period in the southern basin of the Caspian Sea were primarily influenced by the general circulation pattern of the region. This circulation pattern played a significant role in shaping the current profiles observed during the measurements. In terms of the surface current speed, the maximum recorded value was approximately 200 cm/s, which occurred in January. This indicates that there were instances of relatively high-speed currents in the southern basin of the Caspian Sea during that time. The evaluation of inter-annual variability in vertical structure and seawater temperature profiles during the monitoring period confirmed the presence of seasonal stratification in the water column of the southern basin of the Caspian Sea. This stratification was observed to consist of different layers, including the surface mixed layer, thermocline, and deep-water layers. The formation of these layers is indicative of the seasonal variations in temperature and density within the water column. The vertical changes in the water’s physical parameters during the monitoring period revealed the formation of stratification in the southern basin of the Caspian Sea. In March, it was observed that the water temperature decreased from 11.5°C at the surface to 8.5°C at a depth of 100 m, indicating the presence of a temperature gradient. As the monitoring progressed into May, the stratification became stronger, with the surface water temperature reaching around 23°C. By August, the surface layer of the sea water experienced a significant increase in temperature, reaching 29°C. These observations highlight the development of stratification and the seasonal variations in water temperature during the monitoring period in spring and summer seasons. The water temperature beneath the thermocline layer, specifically at a depth of 100 meters, was recorded to be around 8-8.5 oC. Additionally, the water salinity in the water column exhibited fluctuations between 12-12.5 (psu). Monitoring and understanding physical properties variations are crucial for assessing the oceanographic conditions and their potential impact on marine ecosystems in the southern basin of the Caspian Sea.

show abstract

Evaluation of trophic state conditions in the three urban perennial lakes of the Coimbatore district, Tamil Nadu: Based on water quality parameters and rotifer composition

Mohan,

Prabha

2024

HydroResearch

View full text Add to dashboard Cite

Variations of dissolved oxygen concentrations under influence of seasonal stratification using deep-water observations in the southern region of the Caspian Sea

Cited by 3 publications

References 46 publications

Oxygen-driven divergence of marine group II archaea reflected by transitions of superoxide dismutases

Oxygen-driven divergence of marine group II archaea reflected by transitions of superoxide dismutases

Flow measurement in the southern coast of the Caspian Sea

Evaluation of trophic state conditions in the three urban perennial lakes of the Coimbatore district, Tamil Nadu: Based on water quality parameters and rotifer composition

Contact Info

Product

Resources

About