scholarly journals Adaptation of Coccomyxa sp. to Extremely Low Light Conditions Causes Deep Chlorophyll and Oxygen Maxima in Acidic Pit Lakes

2020 ◽  
Vol 8 (8) ◽  
pp. 1218
Author(s):  
Javier Sánchez-España ◽  
Carmen Falagán ◽  
Diana Ayala ◽  
Katrin Wendt-Potthoff
Keyword(s):  
Iron Concentration ◽  
Nutrient Distribution ◽  
Low Light ◽  
Physico Chemical ◽  
Pit Lakes ◽  
Low Diversity ◽  
Photosynthetic Oxygen ◽  
Characteristic Layers ◽  
Harsh Conditions ◽  
Phototrophic Community

Deep chlorophyll maxima (DCM) and metalimnetic oxygen maxima (MOM) are outstanding biogeochemical features of acidic pit lakes (APL). However, knowledge of the eukaryotic phototrophs responsible for their formation is limited. We aimed at linking the dynamics of phototrophic communities inhabiting meromictic APL in Spain with the formation of these characteristic layers. Firstly, the dynamics of DCM and MOM and their relation to physico-chemical parameters (photosynthetically active radiation (PAR), pH, dissolved ferric iron concentration, temperature), pigments and nutrient distribution is described; secondly, the phototrophic community composition is studied through a combination of microscopy, biomolecular and “omics” tools. Phototrophic communities of the studied APL show a low diversity dominated by green microalgae, specifically Coccomyxa sp., which have been successfully adapted to the chemically harsh conditions. DCM and MOM are usually non-coincident. DCM correspond to layers where phototrophs have higher chlorophyll content per cell to cope with extremely low PAR (<1 µmol m−2 s−1), but where photosynthetic oxygen production is limited. MOM correspond to shallower waters with more light, higher phytoplankton biomass and intense photosynthetic activity, which affects both oxygen concentration and water temperature. The main drivers of DCM formation in these APL are likely the need for nutrient uptake and photo-acclimation.

scholarly journals Phytoplankton in extreme environments: importance and consequences of habitat permanency

Hydrobiologia ◽  
2020 ◽  
Vol 848 (1) ◽  
pp. 157-176 ◽  
Author(s):  
Judit Padisák ◽  
Luigi Naselli-Flores
Keyword(s):  
Extreme Environments ◽  
Single Species ◽  
Physiological Adaptation ◽  
Low Light ◽  
High Metal Content ◽  
Top Predators ◽  
Physiological Adaptations ◽  
Characteristic Species ◽  
Compositional Diversity ◽  
Harsh Conditions

AbstractThere is hardly any sunshine exposed surface on this Earth, be it water or terrain, which would not support some biota. Still, many habitats offer harsh conditions requiring specialized physiological adaptations to survive. These environments are referred to as extremes; often inhabited by extremophilic organisms. In this review, characteristic species and assemblage properties of phytoplankton inhabiting extreme environments (especially lakes and pools where planktic life is potentially possible and independently of their origin) in terms of alkalinity, acidity, DOC, salinity, temperature, light and mixing regime will be outlined. Lakes characterized by more than a single extreme are common (e.g. saline + alkaline; acidic + high DOC + high metal content + low light). At the edge of extremes (e.g. pH of 1; salinity over ~ 100–150 g l−1) single species with appropriate physiological adaptation are selected and the phytoplankton is often dominated by a single species (monodominant) setting compositional diversity to zero. Under less extreme conditions permanent equilibria may persist; in many cases over several years in contrast to „average” lakes where equilibria are rare and ephemeral. Food webs depending on „extreme phytoplankton” are often atypical for example because the microbial loop is of prior importance or because birds are top predators.

scholarly journals Prospects for metazoan life in sub-glacial Antarctic lakes: the most extreme life on Earth?

2019 ◽  
Vol 18 (05) ◽  
pp. 416-419 ◽  
Author(s):  
Sven Thatje ◽  
Alastair Brown ◽  
Claus-Dieter Hillenbrand
Keyword(s):  
Hydrothermal Vents ◽  
Pure Water ◽  
Hydrothermal Activity ◽  
Microbial Life ◽  
Lake Vostok ◽  
Physico Chemical ◽  
Physiological Adaptations ◽  
Subglacial Lakes ◽  
Life On Earth ◽  
Harsh Conditions

AbstractAbout 400 subglacial lakes are known from Antarctica. The question of whether life unique of subglacial lakes exists has been paramount since their discovery. Despite frequent evidence of microbial life mostly from accretion ice, subglacial lakes are characterized by physiologically hostile conditions to metazoan life, as we know it. Pure water (salinity ≤0.4–1.2%), extreme cold (−3°C), high hydrostatic pressure, areas of limited or no oxygen availability and permanent darkness altogether require physiological adaptations to these harsh conditions. The record of gene sequences including some associated with hydrothermal vents does foster the idea of metazoan life in Lake Vostok. Here, we synthesize the physico-chemical environment surrounding sub-glacial lakes and potential sites of hydrothermal activity and advocate that the physico-chemical stability found at these sites may be the most likely sites for metazoan life to exist. The unique conditions presented by Lake Vostok may also offer an outlook on life to be expected in extra-terrestrial subglacial environments, such as on Jupiter's moon Europa or Saturn's moon Enceladus.

scholarly journals Control of Photosynthetic and High-Light-Responsive Genes by the Histidine Kinase DspA: Negative and Positive Regulation and Interactions between Signal Transduction Pathways

2004 ◽  
Vol 186 (12) ◽  
pp. 3882-3888 ◽  
Author(s):  
Hui-Yi Hsiao ◽  
Qingfang He ◽  
Lorraine G. van Waasbergen ◽  
Arthur R. Grossman
Keyword(s):  
Histidine Kinase ◽  
Constitutive Expression ◽  
Companion Paper ◽  
High Light ◽  
Photosynthetic Oxygen Evolution ◽  
Wild Type ◽  
Low Light ◽  
Photosynthetic Oxygen ◽  
Inducible Genes ◽  
Encoding Genes

ABSTRACT We have deleted a gene for a sensor histidine kinase, dspA (or hik33), in the cyanobacterium Synechocystis sp. strain PCC6803. In low and moderate light, the mutant grew slowly under photoautotrophic conditions, with a doubling time of ∼40 h, and had severely reduced photosynthetic oxygen evolution. When the mutant was maintained in low or moderate light in the presence of glucose, its growth rate was only somewhat lower than that of wild-type cells. However, the mutant was light sensitive and rapidly died in high light. Furthermore, levels of many transcripts encoding genes associated with photosynthesis were altered in the mutant relative to wild-type Synechocystis sp. strain PCC6803 both in low light and following exposure to high light. There was constitutive expression of several high-light-inducible genes, including hli, psbAIII, and gpx2; there was little increased accumulation of sodB mRNA in high light; and the cells failed to accumulate cpcBA and psaAB mRNAs in low light in the presence of glucose, although a normal decline in the levels of these mRNAs was observed during exposure to high light. These results suggest that DspA is involved in controlling sets of photosynthetic and high-light-responsive genes, either directly or indirectly. These and other results, some of which are presented in a companion paper (C.-J. Tu, J. Shrager, R. Burnap, B. L. Postier, and A. R. Grossman, J. Bacteriol. 186:3889-3902, 2004), suggest that DspA acts as a global regulator that helps coordinate cellular metabolism with growth limitations imposed by environmental conditions.

Physico-chemical gradients and meromictic stratification in Cueva de la Mora and other acidic pit lakes of the Iberian Pyrite Belt

2009 ◽  
Vol 28 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Javier Sánchez España ◽  
Enrique López Pamo ◽  
Marta Diez ◽  
Esther Santofimia
Keyword(s):  
Iberian Pyrite Belt ◽  
Chemical Gradients ◽  
Physico Chemical ◽  
Pit Lakes

scholarly journals Temporal and Bathymetric Variation of Epiphytic Microalgae on Posidonia oceanica (L.) Delile Leaves in Gökçeada (North Aegean, Turkey)

2020 ◽  
Vol 20 (10) ◽  
pp. 727-737
Author(s):  
Aysu Guresen ◽  
Sedat Ozan Guresen ◽  
Yelda Aktan
Keyword(s):  
Leaf Surface ◽  
Environmental Parameters ◽  
Posidonia Oceanica ◽  
Filamentous Cyanobacteria ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Low Diversity ◽  
North Aegean ◽  
Benthic Ecosystems ◽  
Surface Improvement

Epiphytic microalgae attached to Posidonia oceanica leaves play a significant role through primary production, nutrient cycling and trophic fluxes in benthic ecosystems. Due to their sensitivity, epiphytic microalgae respond to environmental alterations more quickly than their host. The aim of this study is therefore to evaluate the ecological quality in Gökçeada Underwater Park (North Aegean) using epiphytic microalgal composition and abundance. In this respect, P. oceanica shoots are collected at 6m, 15m and 28m in May, July, October 2009 and January 2010 to estimate the microalgal composition and abundance. Also, P. oceanica descriptors and physico-chemical parameters in the water column of the meadow lower limit are measured. Leaf surface improvement through greater depths, have provided a convenient substratum for epiphytic colonization. A total of 56 taxa belonging to epiphytic microalgae are composed of Bacillariophyceae (91%), Cyanophyceae (7%) and Dinophyceae (2%). Temporal and bathymetric dynamics of the epiphytic community structure and abundance depend on the environmental parameters; such as leaf surface, nutrients and turbidity. Also, a mucilage phenomenon, resulted in a low diversity due to the dominancy of filamentous cyanobacteria. Necessary data is supplied for a less evaluated region affected by agricultural activities and urbanization in the recent years.

scholarly journals Independent iron and light limitation in a low-light-adapted Prochlorococcus from the deep chlorophyll maximum

2020 ◽  
Vol 15 (1) ◽  
pp. 359-362
Author(s):  
Nicholas J. Hawco ◽  
Feixue Fu ◽  
Nina Yang ◽  
David A. Hutchins ◽  
Seth G. John
Keyword(s):  
Light Intensity ◽  
High Efficiency ◽  
Iron Concentration ◽  
Euphotic Zone ◽  
Theoretical Models ◽  
Light Limitation ◽  
Deep Chlorophyll Maximum ◽  
North Pacific Subtropical Gyre ◽  
Low Light ◽  
Chlorophyll Maximum

AbstractThroughout the open ocean, a minimum in dissolved iron concentration (dFe) overlaps with the deep chlorophyll maximum (DCM), which marks the lower limit of the euphotic zone. Maximizing light capture in these dim waters is expected to require upregulation of Fe-bearing photosystems, further depleting dFe and possibly leading to co-limitation by both iron and light. However, this effect has not been quantified for important phytoplankton groups like Prochlorococcus, which contributes most of the productivity in the oligotrophic DCM. Here, we present culture experiments with Prochlorococcus strain MIT1214, a member of the Low Light 1 ecotype isolated from the DCM in the North Pacific subtropical gyre. Under a matrix of iron and irradiance matching those found at the DCM, the ratio of Fe to carbon in Prochlorococcus MIT1214 cells ranged from 10–40 × 10−6 mol Fe:mol C and increased with light intensity and growth rate. These results challenge theoretical models predicting highest Fe:C at lowest light intensity, and are best explained by a large photosynthetic Fe demand that is not downregulated at higher light. To sustain primary production in the DCM with the rigid Fe requirements of low-light-adapted Prochlorococcus, dFe must be recycled rapidly and at high efficiency.

IMPACT OF TANNERIES ON GROUND WATER CONTAMINATION IN UNNAO DISTRICT

2016 ◽  
Vol 2 (2) ◽  
pp. 110-114 ◽  
Author(s):  
Shradha Sinha ◽  
Neeraj Agarwal ◽  
Shailja Pandey ◽  
Vandana Grover
Keyword(s):  
Water Quality ◽  
Ground Water ◽  
Iron Concentration ◽  
Chemical Parameters ◽  
Ground Water Quality ◽  
High Concentration ◽  
Physico Chemical ◽  
Two Parameters ◽  
The Impact

Attempt is made to understand the impact of tanneries on ground water quality of Unnao. Study was undertaken to evaluate physico-chemical parameters and chromium, lead iron concentration in ground water near tannery industries. The results revealed that only two parameters fluoride and chromium are present in slight high concentration than permissible limit. Ground water quality % sample compliance / violation with respect to BIS standard were also studied.

Natural genetic variation of Arabidopsis thaliana root morphological response to magnesium supply

2015 ◽  
Vol 66 (12) ◽  
pp. 1249 ◽  
Author(s):  
Qiying Xiao ◽  
Hugues De Gernier ◽  
László Kupcsik ◽  
Jérôme De Pessemier ◽  
Klaus Dittert ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root System ◽  
Root Morphology ◽  
System Architecture ◽  
Lateral Roots ◽  
Iron Concentration ◽  
Primary Root ◽  
Root System Architecture ◽  
Mineral Nutrient ◽  
Nutrient Distribution

Plants dynamically cope with the variability of mineral nutrient distribution in soil by constantly modulating nutrient uptake and shaping root-system architecture. The changes in root morphology in response to major essential elements are largely documented, but little is known about how the root system responds to magnesium (Mg) availability. Thirty-six natural accessions of the model species Arabidopsis thaliana were subjected to an in vitro screen for identifying variation in root system architecture in response to Mg availability. Response of root morphology was observed on 2-dimensional agar plates. Low Mg supply repressed the elongation of the lateral roots more than of the primary root. However, some accessions exhibited higher number and length of lateral roots than the reference Columbia-0. Across all accessions, the root morphological traits did not correlate with tissue Mg concentrations. Interestingly, shoot calcium and root phosphorus concentrations were positively correlated with the number and length of lateral roots, whereas root iron concentration was negatively correlated with the primary root length. The diversity of root phenotypes identified in this report is a useful resource to study the genetic component determining root morphology in response to Mg availability.

scholarly journals ALGAL DYNAMICS OF RIVER PANDU IN RELATION TO AMBIENT ENVIRONMENT

2014 ◽  
Vol 20 ◽  
pp. 9-17
Author(s):  
Sunita Verma ◽  
Divya Tiwari ◽  
Ajay Verma
Keyword(s):  
Fly Ash ◽  
Aquatic Environment ◽  
Algal Growth ◽  
Current Status ◽  
Species Number ◽  
Anthropogenic Stress ◽  
Algal Population ◽  
Sharp Decline ◽  
Physico Chemical ◽  
Low Diversity

An investigation on river Pandu in the year 2009-2010 was carried out to explore its current status in terms of physico-chemical and phycological profile. The study revealed that algal spectrum of the river was connected with the intensity of pollution in the river. River, at present is a perturbed ecosystem due to heavy anthropogenic stress on it. Despite abundant nutrients and other factors responsible for propping algal growth, river had a meak algal population and low diversity as compared to other perennial rivers indicating the grossly polluted unhealthy condition of the river. Algae are natural inhabitants of aquatic environment; and act as natural purifiers due to their nutrient gleaning and oxygenating capabilities; they are more sensitive than animals to industrial and municipal wastes. Maximum number of species existed at station-1 followed by stations-4 and 6 and then at station-5. Lowest species representation has been noticed at stations-2 and 3. Species number and algal population too declined sharply at stations-2 and 3 as compared to station-I. Sharp decline in algal population at stations-2 and 3 may be attributed to certain obvious reasons such as low transparency and reduced illumination as a consequence of residual fly ash discharged by PTPP drain at station-2. Except station-1, all downstream stations show grossly polluted condition of the river.DOI: http://dx.doi.org/10.3126/eco.v20i0.11325Ecoprint: An International Journal of EcologyVol. 20, 2013Page : 9-17

Insights into community of photosynthetic microorganisms from permafrost

2020 ◽  
Vol 96 (12) ◽  
Author(s):  
Tatiana A Vishnivetskaya ◽  
Abraham L Almatari ◽  
Elena V Spirina ◽  
Xiaofen Wu ◽  
Daniel E Williams ◽  
...  
Keyword(s):  
Green Algae ◽  
The Arctic ◽  
Low Light ◽  
Prolonged Incubation ◽  
Photosynthetic Organisms ◽  
Photosynthetic Microorganisms ◽  
Permafrost Thawing ◽  
Siberian Permafrost ◽  
Harsh Conditions ◽  
Permafrost Sediments

ABSTRACT This work integrates cultivation studies of Siberian permafrost and analyses of metagenomes from different locations in the Arctic with the aim of obtaining insights into the community of photosynthetic microorganisms in perennially frozen deposits. Cyanobacteria and microalgae have been described in Arctic aquatic and surface soil environments, but their diversity and ability to withstand harsh conditions within the permafrost are still largely unknown. Community structure of photosynthetic organisms in permafrost sediments was explored using Arctic metagenomes available through the MG-RAST. Sequences affiliated with cyanobacteria represented from 0.25 to 3.03% of total sequences, followed by sequences affiliated with Streptophyta (algae and vascular plants) 0.01–0.45% and Chlorophyta (green algae) 0.01–0.1%. Enrichment and cultivation approaches revealed that cyanobacteria and green algae survive in permafrost and they could be revived during prolonged incubation at low light intensity. Among photosynthetic microorganisms isolated from permafrost, the filamentous Oscillatoria-like cyanobacteria and unicellular green algae of the genus Chlorella were dominant. Our findings suggest that permafrost cyanobacteria and green algae are expected to be effective members of the re-assembled community after permafrost thawing and soil collapse.

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