The role of ultraviolet radiation in structuring epilithic algal communities in Rocky Mountain montane lakes: evidence from pigments and taxonomy

2004 ◽  
Vol 61 (8) ◽  
pp. 1461-1474 ◽  
Author(s):  
Suzanne E Tank ◽  
David W Schindler
Keyword(s):  
Ultraviolet Radiation ◽  
Photosynthetic Pigments ◽  
Algal Growth ◽  
Rocky Mountain ◽  
Grazing Pressure ◽  
Community Diversity ◽  
Algal Community ◽  
Nutrient Concentrations ◽  
Algal Communities

We investigated changes in the community structure of epilithic (rock-dwelling) algae brought about by ultraviolet-A and -B radiation (UV-A and UV-B, respectively), using measurements of biovolume of individual taxa, and taxonomically diagnostic photosynthetic pigments. We undertook our study in four Canadian Rocky Mountain montane lakes, where downwelling ultraviolet radiation (UVR) can be intense. Although taxonomic counts revealed significant decreases in algal community diversity under UV-A and UV-B exposure, they revealed no other significant trends in algal community composition. Instead, redundancy analysis using these counts suggested that variations in nutrient concentrations were most important in structuring these communities. Photosynthetic pigments decreased significantly under UV-A and UV-B exposure. This decrease was much more striking for carotenoid than for chlorophyll concentrations, despite the photoprotective properties of many carotenoid pigments. Grazed carotenoids have been shown to be more resistant to degradation than grazed chlorophylls. We suggest that an observed increase in grazing pressure in our UVR-shielded communities counteracted increases in algal growth, but that increased algal growth rates were reflected by increased concentrations of slowly degrading carotenoids. Our study suggests that other factors, such as nutrients and grazers, are more important than UVR for structuring epilithic algal communities in our study lakes.

scholarly journals Contribution of Internal Nutrients Loading on the Water Quality of a Reservoir

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1409 ◽  
Author(s):  
Hye Won Lee ◽  
Yong Seok Lee ◽  
Jonggun Kim ◽  
Kyoung Jae Lim ◽  
Jung Hyun Choi
Keyword(s):  
Water Quality ◽  
Sediment Load ◽  
Transport Model ◽  
Three Dimensional ◽  
Algal Growth ◽  
Nutrient Concentrations ◽  
Internal Load ◽  
Phosphorus Flux

Sediment plays an important role in the water quality of a lake by acting as both a nutrient source and sink. The amount of phosphorus and nitrogen in the water depends on the internal load from the sediment as well as the external load. To estimate the effects of sediment load on the water quality of a reservoir, we applied a three-dimensional hydrodynamic and transport model based on the benthic chamber experimental results at Euiam Lake, South Korea. As shown in the sensitivity analysis results, the eutrophication period could be significantly extended by a change of phosphorus flux rates from the sediments. The increased phosphorus flux from the sediments intensifies the algal growth of Euiam Lake, which could cause serious algal bloom during spring and fall. This study provides information on nutrient concentrations in the sediment of Euiam Lake, verifies the role of the sediment as a source or sink of nutrients, and evaluates the effect of sediment release of nutrients and contaminants on water quality. This research is a useful tool in determining the effects of internal load in lakes and establishing the operation guideline for sediment management in order to maintain feasible water quality for beneficial use.

Role of residual biofilm in the recolonization of rocky intermittent streams by benthic algae

2000 ◽  
Vol 51 (7) ◽  
pp. 725 ◽  
Author(s):  
Belinda J. Robson
Keyword(s):  
Algal Growth ◽  
Benthic Algae ◽  
Algal Community ◽  
Transplant Experiment ◽  
Intermittent Streams ◽  
Naturally Occurring ◽  
Eastern Australia ◽  
Algal Biofilm ◽  
Stream Biota

Human use of stream flow for water supply may increase the duration and/or frequency of dry periods in intermittent streams, but there is little information on the effect of this change on in-stream flora or fauna. To predict the effects of dry periods on stream biota, it is necessary to understand the relative roles of various sources of recolonization. A transplant experiment was used to test the hypothesis that the dry residual algal biofilm on stones in intermittent streams is an important source of algal growth when the streams are re-wetted. Two sites were chosen, one on each of two intermittent streams in south-eastern Australia. Rocks at the sites differed in the amount of naturally occurring residual biofilm on them. Forty rocks were transplanted between the sites and counts of algal densities were made from samples taken one and five weeks after flow recommenced. At one of the sites, where the biofilm was dominated by Cyanobacteria, dry residual biofilm strongly influenced the developing algal community at both one and five weeks after flow recommenced. At the other site the influence of dry biofilm was limited after five weeks, implying that other sources of algal recolonization were influential there.

scholarly journals The Impact of Ultraviolet Radiation on the Aetiology and Development of Uveal Melanoma

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1700
Author(s):  
Melissa Chalada ◽  
Charmaine A. Ramlogan-Steel ◽  
Bijay P. Dhungel ◽  
Christopher J. Layton ◽  
Jason C. Steel
Keyword(s):  
Risk Factors ◽  
Ultraviolet Radiation ◽  
Uveal Melanoma ◽  
World Health Organisation ◽  
World Health ◽  
Genetic Mutations ◽  
High Incidence ◽  
The World ◽  
The Impact

Uveal melanoma (UM) is currently classified by the World Health Organisation as a melanoma caused by risk factors other than cumulative solar damage. However, factors relating to ultraviolet radiation (UVR) susceptibility such as light-coloured skin and eyes, propensity to burn, and proximity to the equator, frequently correlate with higher risk of UM. These risk factors echo those of the far more common cutaneous melanoma (CM), which is widely accepted to be caused by excessive UVR exposure, suggesting a role of UVR in the development and progression of a proportion of UM. Indeed, this could mean that countries, such as Australia, with high UVR exposure and the highest incidences of CM would represent a similarly high incidence of UM if UVR exposure is truly involved. Most cases of UM lack the typical genetic mutations that are related to UVR damage, although recent evidence in a small minority of cases has shown otherwise. This review therefore reassesses statistical, environmental, anatomical, and physiological evidence for and against the role of UVR in the aetiology of UM.

scholarly journals Water quality drives the regional patterns of an algal metacommunity in interconnected lakes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Min Sung Kim ◽  
Seok Hyun Ahn ◽  
In Jae Jeong ◽  
Tae Kwon Lee
Keyword(s):  
Water Quality ◽  
Community Assembly ◽  
River Flow ◽  
Geographical Area ◽  
Oxygen Demand ◽  
Algal Community ◽  
Regional Patterns ◽  
Algal Communities ◽  
Species Sorting ◽  
Metacommunity Structure

AbstractThe metacommunity approach provides insights into how the biological communities are assembled along the environmental variations. The current study presents the importance of water quality on the metacommunity structure of algal communities in six river-connected lakes using long-term (8 years) monitoring datasets. Elements of metacommunity structure were analyzed to evaluate whether water quality structured the metacommunity across biogeographic regions in the riverine ecosystem. The algal community in all lakes was found to exhibit Clementsian or quasi-Clementsian structure properties such as significant turnover, grouped and species sorting indicating that the communities responded to the environmental gradient. Reciprocal averaging clearly classified the lakes into three clusters according to the geographical region in river flow (upstream, midstream, and downstream). The dispersal patterns of algal genera, including Aulacoseira, Cyclotella, Stephanodiscus, and Chlamydomonas across the regions also supported the spatial-based classification results. Although conductivity, chemical oxygen demand, and biological oxygen demand were found to be important variables (loading > |0.5|) of the entire algal community assembly, water temperature was a critical factor in water quality associated with community assembly in each geographical area. These results support the notion that the structure of algal communities is strongly associated with water quality, but the relative importance of variables in structuring algal communities differed by geological regions.

scholarly journals Ultraviolet Radiation and Chronic Inflammation—Molecules and Mechanisms Involved in Skin Carcinogenesis: A Narrative Review

Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 326
Author(s):  
Magdalena Ciążyńska ◽  
Irmina Olejniczak-Staruch ◽  
Dorota Sobolewska-Sztychny ◽  
Joanna Narbutt ◽  
Małgorzata Skibińska ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Chronic Inflammation ◽  
Potential Role ◽  
Tumor Formation ◽  
Skin Carcinogenesis ◽  
Molecular Networks ◽  
Cancer Therapies ◽  
Inflammatory Microenvironment ◽  
Skin Cancers

The process of skin carcinogenesis is still not fully understood. Both experimental and epidemiological evidence indicate that chronic inflammation is one of the hallmarks of microenvironmental-agent-mediated skin cancers and contributes to its development. Maintaining an inflammatory microenvironment is a condition leading to tumor formation. Multiple studies focus on the molecular pathways activating tumorigenesis by inflammation and indicate several biomarkers and factors that can improve diagnostic and prognostic processes in oncology and dermatology. Reactive oxygen species produced by ultraviolet radiation, oxidizers, or metabolic processes can damage cells and initiate pro-inflammatory cascades. Considering the potential role of inflammation in cancer development and metastasis, the identification of early mechanisms involved in carcinogenesis is crucial for clinical practice and scientific research. Moreover, it could lead to the progress of advanced skin cancer therapies. We focus on a comprehensive analysis of available evidence and on understanding how chronic inflammation and ultraviolet radiation can result in skin carcinogenesis. We present the inflammatory environment as complex molecular networks triggering tumorigenesis and constituting therapeutic targets.

5-MOP Induced Protection Against Epidermal DNA Damage by Ultraviolet Radiation in Human Skin: The Role of the Skin Type

1991 ◽  
pp. 201-209
Author(s):  
Antony R. Young ◽  
Christopher S. Potten ◽  
Caroline A. Chadwick ◽  
Gillian M. Murphy ◽  
A. Jeffrey Cohen
Keyword(s):  
Dna Damage ◽  
Ultraviolet Radiation ◽  
Human Skin ◽  
Skin Type

scholarly journals Feeding patterns in Eubranchipus grubii (Dybowski 1860) (Branchiopoda: Anostraca) and its potential influence on the phytoplankton communities of vernal pools

2018 ◽  
Vol 77 (2) ◽  
Author(s):  
Sofia Celewicz ◽  
Michał Jan Czyż ◽  
Bartłomiej Gołdyn
Keyword(s):  
Cell Volume ◽  
Phytoplankton Community ◽  
Grazing Pressure ◽  
Potential Influence ◽  
Filter Feeder ◽  
Algal Communities ◽  
Phytoplankton Communities ◽  
Fairy Shrimps ◽  
The Mean ◽  
And Control

Filtration patterns in the fairy shrimp Eubranchipus grubii were analysed under laboratory conditions using water containing phytoplankton from their actual locality in western Poland. After 48 hours of feeding, we compared the structure of algal communities in water samples in treatments with males, females and control. The mean filtration rate for E. grubii was relatively high (14,488 mL h-1) in comparison to other crustacean filter feeders and was higher for females than for males. Fairy shrimps grazed effectively on all 11 dominant phytoplankton taxa and there was no sign of overall preferences with regard to taxon, cell volume, length or shape. Female fairy shrimps removed significantly more cells of three taxa (Cryptomonas erosa, C. ovata and Trachelomonas volvocina). The differences between sexes did not depend on the cell volume or length of particular phytoplankton taxa but were significantly related to their initial abundance, initial biomass and shape. The higher the abundance and biomass of the algal taxa, the more intensively it was grazed by females than by males. Females were also observed to graze more on spherical and elongated cells. In conclusion, our results show E. grubii to be an effective, generalist filter feeder capable of significantly influencing the phytoplankton community of a vernal pool. Possible implications of such grazing pressure are also discussed.

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