Influence of meromixia on the distribution of zoobenthos and zooplankton in the salt soda lake Doroninskoe

Abstract Meromictic soda lakes are considered models of reservoirs of the Early Proterozoic. Lake Doroninskoe belongs to a rare type of moderately salty alkaline soda lake with a carbonate type of salinity and pronounced meromixia. Studies and publications on the zoobenthos of the lake are rare. In 2005–2007, studies of zoobenthos and zooplankton of the lake were carried out. Meromixia of the water column caused the stable presence of zooplankton only in a layer up to 4 m. The distribution of the taxonomic abundance, quantitative development and structure of zoobenthos in the lake corresponds to the stratification of the water column into mixolimnion, chemocline and monimolimnion. Bottom biotopes and water column layers deeper than 4 m were uninhabited, which is probably due to the lack of oxygen and high hydrogen sulphide content in the bottom water layers due to meromixia. A similar distribution of zooplankton in Lake Doroninskoe and its mesocosm model was revealed.

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Biogeochemical processes and buffering capacity concurrently affect acidification in a seasonally hypoxic coastal marine basin

Biogeosciences ◽

10.5194/bg-12-1561-2015 ◽

2015 ◽

Vol 12 (5) ◽

pp. 1561-1583 ◽

Cited By ~ 47

Author(s):

M. Hagens ◽

C. P. Slomp ◽

F. J. R. Meysman ◽

D. Seitaj ◽

J. Harlay ◽

...

Keyword(s):

Seasonal Variation ◽

Primary Production ◽

Water Column ◽

Bottom Water ◽

Substantial Reduction ◽

Buffering Capacity ◽

Total Alkalinity ◽

Acid Base ◽

Data Set ◽

Ph Fluctuations

Abstract. Coastal areas are impacted by multiple natural and anthropogenic processes and experience stronger pH fluctuations than the open ocean. These variations can weaken or intensify the ocean acidification signal induced by increasing atmospheric pCO2. The development of eutrophication-induced hypoxia intensifies coastal acidification, since the CO2 produced during respiration decreases the buffering capacity in any hypoxic bottom water. To assess the combined ecosystem impacts of acidification and hypoxia, we quantified the seasonal variation in pH and oxygen dynamics in the water column of a seasonally stratified coastal basin (Lake Grevelingen, the Netherlands). Monthly water-column chemistry measurements were complemented with estimates of primary production and respiration using O2 light–dark incubations, in addition to sediment–water fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TA). The resulting data set was used to set up a proton budget on a seasonal scale. Temperature-induced seasonal stratification combined with a high community respiration was responsible for the depletion of oxygen in the bottom water in summer. The surface water showed strong seasonal variation in process rates (primary production, CO2 air–sea exchange), but relatively small seasonal pH fluctuations (0.46 units on the total hydrogen ion scale). In contrast, the bottom water showed less seasonality in biogeochemical rates (respiration, sediment–water exchange), but stronger pH fluctuations (0.60 units). This marked difference in pH dynamics could be attributed to a substantial reduction in the acid–base buffering capacity of the hypoxic bottom water in the summer period. Our results highlight the importance of acid–base buffering in the pH dynamics of coastal systems and illustrate the increasing vulnerability of hypoxic, CO2-rich waters to any acidifying process.

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Determination of important enzymes and antimicrobial resistances of gram-positive haloalkaliphilic bacteria isolated from Salda Lake

Ege Journal of Fisheries and Aquatic Sciences ◽

10.12714/egejfas.38.3.14 ◽

2021 ◽

Vol 38 (3) ◽

pp. 375-382

Author(s):

Pınar Çağlayan

Keyword(s):

Bacillus Subtilis ◽

Soda Lakes ◽

Soda Lake ◽

16S Rrna Gene Sequencing ◽

Extreme Environment ◽

Rrna Gene ◽

Sequencing Analysis ◽

Haloalkaliphilic Bacteria ◽

Rrna Gene Sequencing

As an extreme environment, soda lakes harbor various haloalkaliphilic microorganisms. Salda Lake is one of the natural soda lake (pH˃9) in Turkey. Haloalkaliphiles are unique microorganisms in their ability to live in high alkaline and high saline conditions, and play an important role in biodegradation and bioremediation of hydrocarbons. Hence, the aims of this study were to isolate haloalkaliphilic bacteria from water sample of Salda Lake, to identify these isolates by both conventional and molecular methods, to screen their industrially important enzymes, and to investigate their antimicrobial resistance profiles. Six isolates were identified as Bacillus horneckiae, Bacillus subtilis, Bacillus paramycoides, Bacillus pumilus, Staphylococcus epidermidis, Bacillus haynesii according to 16S rRNA gene sequencing analysis. The industrially important enzymes (amylase, cellulase, pullulanase, lipase, urease, protease, caseinase, oxidase, catalase) were produced by haloalkaliphilic isolates. These enzymes maybe used in alkaline and saline industrial processes. Although Bacillus subtilis was susceptible to all antibiotics, other isolates showed resistance to at least one antibiotic. The resistance against antibiotics were found as ampicillin/sulbactam 83%, amoxycillin/clavulanic acid 83%, ampicillin 67%, mupirocin 67%, chloramphenicol 50%, tetracycline 50%, imipenem 50%, meropenem 50%, cefadroxil 17%. These bacteria may have develope resistance to antibiotics that entering their natural environment in different ways.

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Parameterization of biogeochemical sediment–water fluxes using in situ measurements and a diagenetic model

Biogeosciences ◽

10.5194/bg-13-77-2016 ◽

2016 ◽

Vol 13 (1) ◽

pp. 77-94 ◽

Cited By ~ 12

Author(s):

A. Laurent ◽

K. Fennel ◽

R. Wilson ◽

J. Lehrter ◽

R. Devereux

Keyword(s):

Water Column ◽

Bottom Water ◽

In Situ Measurements ◽

Nutrient Loads ◽

Water Fluxes ◽

Overlying Water ◽

Louisiana Shelf ◽

Biogeochemical Models ◽

Bottom Waters

Abstract. Diagenetic processes are important drivers of water column biogeochemistry in coastal areas. For example, sediment oxygen consumption can be a significant contributor to oxygen depletion in hypoxic systems, and sediment–water nutrient fluxes support primary productivity in the overlying water column. Moreover, nonlinearities develop between bottom water conditions and sediment–water fluxes due to loss of oxygen-dependent processes in the sediment as oxygen becomes depleted in bottom waters. Yet, sediment–water fluxes of chemical species are often parameterized crudely in coupled physical–biogeochemical models, using simple linear parameterizations that are only poorly constrained by observations. Diagenetic models that represent sediment biogeochemistry are available, but rarely are coupled to water column biogeochemical models because they are computationally expensive. Here, we apply a method that efficiently parameterizes sediment–water fluxes of oxygen, nitrate and ammonium by combining in situ measurements, a diagenetic model and a parameter optimization method. As a proof of concept, we apply this method to the Louisiana Shelf where high primary production, stimulated by excessive nutrient loads from the Mississippi–Atchafalaya River system, promotes the development of hypoxic bottom waters in summer. The parameterized sediment–water fluxes represent nonlinear feedbacks between water column and sediment processes at low bottom water oxygen concentrations, which may persist for long periods (weeks to months) in hypoxic systems such as the Louisiana Shelf. This method can be applied to other systems and is particularly relevant for shallow coastal and estuarine waters where the interaction between sediment and water column is strong and hypoxia is prone to occur due to land-based nutrient loads.

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Algal composition and biomass in the tropical soda lake Chitu with focus on seasonal variability of Arthrospira fusiformis (Cyanophyta)

Marine and Freshwater Research ◽

10.1071/mf14426 ◽

2016 ◽

Vol 67 (4) ◽

pp. 483 ◽

Cited By ~ 1

Author(s):

Tadesse Ogato ◽

Demeke Kifle ◽

Brook Lemma

Keyword(s):

Seasonal Variability ◽

Soda Lakes ◽

Soda Lake ◽

Dry Weight ◽

Taxonomic Composition ◽

Algal Community ◽

Environmental Drivers ◽

East African ◽

Chl A ◽

Algal Abundance

The vital ecological functions of the East African soda lakes are much dependent on Arthrospira, which forms a natural nearly monoalgal populations and serves as the main diet for the huge flocks of flamingos in the present study lake Chitu (Ethiopia). This study investigated algal taxonomic composition and biomass, and the seasonal variability in the abundance of Arthrospira fusiformis in response to some environmental drivers (e.g. rainfall, salinity and nutrients) using samples collected over an annual cycle. The algal community was composed of a few taxa (15 species), with exclusive dominance of A. fusiformis. Chlorophyll-a (Chl-a) and dry weight, and abundance of A. fusiformis were notably high and exhibited seasonal variations, with significantly (P<0.05) higher levels of Chl-a and dry weight during the rainy season. The observed strong correlations of algal abundance and biomass with rainfall (positively) and alkalinity-salinity (negatively), probably suggest that hydrological control of the salinity is the major driving force for the seasonal variability of A. fusiformis in the lake. Further hydrological modifications that enhance salinisation may greatly affect A. fusiformis thereby causing instability of the flamingos with eventual impairment of the ecosystem values of the lake.

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Diversity of cultivated aerobic poly-hydrolytic bacteria in saline alkaline soils

10.7287/peerj.preprints.3038v1 ◽

2017 ◽

Author(s):

Dmitry Y. Sorokin ◽

Tatiana V. Kolganova ◽

Tatiana V. Khijniak ◽

Brian E. Jones ◽

Ilya V. Kublanov

Keyword(s):

Soda Lakes ◽

Soda Lake ◽

Rrna Gene ◽

Alkaline Soils ◽

Present Information ◽

Hydrolytic Activities ◽

Hydrolytic Bacteria ◽

Sequences Analysis ◽

Ph Range ◽

Soda Soils

Alkaline saline soils known also as “soda solonchaks” represent a natural soda habitat which differed from soda lake sediments by higher aeration and lower humidity. The microbiology of soda soils, in contrast to the more intensively studied soda lakes, remains poorly explored. In this work we present information on the diversity of culturable aerobic haloalkalitolerant bacteria with various hydrolytic activities from soda soils at different locations in Central Asia and Africa. In total, 180 isolates were obtained by using media with various polymers at pH 10 and 0.6 M total Na+. According to the 16S rRNA gene sequences analysis, most of the isolates belonged to Firmicutes and Actinobacteria. Most isolates possessed multiple hydrolytic activities, including endoglucanase, xylanase, amylase and protease. The pH profiling of selected representatives of actinobacteria and endospore-forming bacteria showed, that the former were facultative alkaliphiles, while the latter were mostly obligate alkaliphiles. The hydrolases of both groups were active at a broad pH range from 6 to 11. Overall, this work demonstrated the presence of a rich hydrolytic bacterial community in soda soils which might be explored further for production of haloalkalistable hydrolases.

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Geochemical Characteristics of Sediment in Tropical Lake Sentani, Indonesia, Are Influenced by Spatial Differences in Catchment Geology and Water Column Stratification

Frontiers in Earth Science ◽

10.3389/feart.2021.671642 ◽

2021 ◽

Vol 9 ◽

Author(s):

Sulung Nomosatryo ◽

Rik Tjallingii ◽

Anja Maria Schleicher ◽

Paulus Boli ◽

Cynthia Henny ◽

...

Keyword(s):

Water Chemistry ◽

Water Column ◽

Pore Water ◽

Bottom Water ◽

Geochemical Characteristics ◽

Tropical Lake ◽

Sediment Composition ◽

Column Structure ◽

Wide Range ◽

Sediment Input

Physical and (bio)chemical processes in the catchment as well as internal lake processes influence the composition of lacustrine sediments. Lake internal processes are a consequence of reactions and fluxes between sediment, porewater and the water column. Due to its separation into four interconnected sub-basins, Lake Sentani, Papua Province, Indonesia, is a unique tropical lake that reveals a wide range of geochemical conditions. The highly diverse geological catchment causes mineralogical and chemical differentiation of the sediment input into each sub-basin. Also, strong morphological differences between the sub-basins result in a unique water column structure for each sub-basin, ranging from fully mixed to meromictic. Given the strong differences in sediment composition and bottom water chemistry among the four sub-basins, Lake Sentani offers a unique chance to study multiple lacustrine systems under identical climate conditions and with a common surface water chemistry. We used sediment cores and water samples and measured physicochemical water column profiles to reveal the geochemical characteristics of the water column, the sediment and pore water for all four sub-basins of Lake Sentani. The chemical composition of the sediment reveals differentiation among the sub-basins according to their sediment input and water column structure. Catchment lithology mainly affects overall sediment composition, whereas pore water chemistry is also affected by water column structure, which is related to basin morphology and water depth. In the meromictic sub-basins the bottom water and sediment pore water appear to form a single continuous system, whereas in those sub-basins with oxygenated bottom water the sediment-water interface forms a pronounced chemical barrier.

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Resuspension and estuarine nutrient cycling: insights from the Neuse River Estuary

Biogeosciences Discussions ◽

10.5194/bgd-7-2767-2010 ◽

2010 ◽

Vol 7 (2) ◽

pp. 2767-2798 ◽

Cited By ~ 1

Author(s):

D. R. Corbett

Keyword(s):

Water Quality ◽

Nutrient Cycling ◽

Water Column ◽

Bottom Water ◽

River Estuary ◽

Neuse River Estuary ◽

Nutrient Concentrations ◽

Neuse River ◽

Advective Flux ◽

The Past

Abstract. For at least the past several decades, North Carolina's Neuse River Estuary (NRE) has been subject to water quality problems relating to increased eutrophication. Research studies initiated in the past several years have addressed the complex nutrient cycles in this system. Most of this research, however, is concerned with the nutrient processes of the water column and the passive diffusion processes of the benthic sedimentary environment. Resuspension of bottom sediments, by bioturbation, tides, or wind-generated waves, may have a significant effect on the flux of nutrients in an estuarine system These processes can result in the advective transport of sediment porewater, rich with nitrogen, phosphorus and carbon, into the water column. Thus, estimates of nutrient and carbon inputs from the sediments may be too low. This study focused on the potential change in porewater and bottom water nutrient concentrations associated with measured resuspension events. Previous research used short-lived radionuclides and meteorological data to characterize the sediment dynamics of the benthic system of the estuary. These techniques in conjunction with the presented porewater inventories allowed evaluation of the depth to which sediments have been disturbed and the advective flux of nutrients to the water column. The largest removal episode occurred in the lower NRE as the result of a wind event and was estimated that the top 2.2 cm of sediment and corresponding porewater were removed. NH4+ advective flux (resuspended) was 2 to 6 times greater than simply diffusion. Phosphate fluxes were estimated to be 15 times greater than the benthic diffusive flux. Bottom water conditions with elevated NH4+ and PO43− indicate that nutrients stored in the sediments continue to play an important role in overall water quality and this study suggests that the advective flux of nutrients to the water column is critical to understand estuarine nutrient cycling.

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Heterotrophic nanoflagellates in the pelagic zone and sediments of the eastern Laptev sea

Океанология ◽

10.31857/s0030-1574596974-986 ◽

2019 ◽

Vol 59 (6) ◽

pp. 974-986

Author(s):

N. G. Kosolapova ◽

D. B. Kosolapov ◽

A. I. Kopylov ◽

A. V. Romanenko

Keyword(s):

Water Column ◽

Heterotrophic Nanoflagellates ◽

Heterotrophic Flagellates ◽

Laptev Sea ◽

Freshwater Input ◽

Water Layers ◽

Quantitative Characteristics ◽

Taxonomic Groups ◽

First Time ◽

The Laptev Sea

For the first time, the species composition of heterotrophic nanoflagellates, their quantitative characteristics, as well as the abundance and biomass of their main food objects: bacteria and picophytoplankton, were determined in the water column and sediments of the Laptev Sea. On a meridional transect from the Lena delta to the deep-sea zone in early autumn an increase in the number and biomass of planktonic flagellates was recorded in the area of the internal shelf, which is impacted by Lena's freshwater input. The pattern of vertical distribution of planktonic flagellates differed in the different parts of the sea, but everywhere their greatest number was confined to either the surface or the near-bottom water layers. Quantitative parameters of planktonic flagellates positively correlated with the temperature, bacterial abundance and biomass and negatively correlated with the water salinity. The abundance and biomass of heterotrophic flagellates in the surface sediments was 34 orders of magnitude higher than in the water column and exceeded those of planktonic flagellates in the shallow sites under 1 m2. A total of 28 species and forms of heterotrophic flagellates have been identified. Representatives of two taxonomic groups: Kinetoplastea and Stramenopiles, which were the most tolerance to the salinity, dominated in the community. The species richness of the flagellates decreased with the water depth and was minimal in the less saline coastal waters and increased in the deep-see area.

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Mineral Vesicles and Chemical Gardens from Carbonate-Rich Alkaline Brines of Lake Magadi, Kenya

Crystals ◽

10.3390/cryst10060467 ◽

2020 ◽

Vol 10 (6) ◽

pp. 467 ◽

Cited By ~ 2

Author(s):

Melese Getenet ◽

Juan Manuel García-Ruiz ◽

Cristóbal Verdugo-Escamilla ◽

Isabel Guerra-Tschuschke

Keyword(s):

Self Assembly ◽

Metal Salt ◽

Recent Observation ◽

Soda Lakes ◽

Soda Lake ◽

Alkaline Solutions ◽

One Pot ◽

Rock Interaction ◽

Lake Magadi ◽

Chemical Gardens

Mineral vesicles and chemical gardens are self-organized biomimetic structures that form via abiotic mineral precipitation. These membranous structures are known to catalyze prebiotic reactions but the extreme conditions required for their synthesis has cast doubts on their formation in nature. Apart from model solutions, these structures have been shown to form in serpentinization-driven natural silica-rich water and by fluid-rock interaction of model alkaline solutions with granites. Here, for the first time, we demonstrate that self-assembled hollow mineral vesicles and gardens can be synthesized in natural carbonate-rich soda lake water. We have synthesized these structures by a) pouring saturated metal salt solutions, and b) by immersing metal salt pellets in brines collected from Lake Magadi (Kenya). The resulting structures are analyzed by using SEM coupled with EDX analysis, Raman spectroscopy, and powder X-ray diffraction. Our results suggest that mineral self-assembly could have been a common phenomenon in soda oceans of early Earth and Earth-like planets and moons. The composition of the obtained vesicles and gardens confirms the recent observation that carbonate minerals in soda lakes sequestrate Ca, thus leaving phosphate behind in solution available for biochemical reactions. Our results strengthens the proposal that alkaline brines could be ideal sites for “one-pot” synthesis of prebiotic organic compounds and the origin of life.

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