Environmental changes affect picoplanktonic composition in Antarctic Peninsula ponds

Antarctic Peninsula is experiencing one of the largest global warming events worldwide.Shallow water bodies generated by the melting of snow in summer are numerous,and they might act as sentinels of climate change due to their rapid response and ability to integrate catchment information.Shifts in climate can influence the structure of microbial communities which dominate these freshwaters ecosystems.Here,we characterize three ponds at Cierva Point(Antarctic Peninsula)by examining their physico-chemical and morphological characteristics and we explored how different factors modify the structure of the microbial community.We studied the abundance and biomass of heterotrophic bacteria,picocyanobacteria and picoeukaryote algae during January and February of two consecutive summers(2017 and 2018).We found that ponds had different limnological characteristics,due to their location,geomorphological features and presence of the surrounding flora and fauna.Physico-chemical parameters as well as microbial community differed between ponds,months and years.In 2017,most ponds were oligo to mesotrophic states.The larger accumulated rainfall(as a result of environmental changes on the Antarctic Peninsula)during 2018,particularly in February,causes nutrient runoff into water bodies.This affects those ponds with the highest seabird circulation,such as gentoo penguin,increasing eutrophication.As a result,picoplanktonic abundances were higher,and the community structure shifts to a largely heterotrophic bacteria dominated one.These results suggest that these communities could act as sentinels to environmental changes,anticipating a future with mostly hypertrophic ponds.

Use of wild trout for PBDE assessment in freshwater environments: Review and summary of critical factors

Certain wild animals represent sentinels to address issues related to environmental pollution,since they can provide integrative data on both pollutant exposure and biological effects.Despite their technological benefits,PBDEs are considered a threat to environmental health due to their persistence,toxicity,and capacity to be accumulated.These pollutants have been found geographically widespread in fish,particularly in predator species such as trout.The aim of this work is to critically review the applicability and usefulness of wild trout for assessing PBDEs in freshwater environments.Reviewed reports include data from highly industrialized areas as well as areas from remote regions with relatively low human activity,including European and North American great lakes and freshwater environments in Europe,Greenland,subarctic areas and Patagonia,respectively.A summary of relevant factors were grouped into organism-specific factors(food habits,age,size,lipid content,sex and reproduction,tissue type,mechanism of contaminant uptake and metabolism),and PBDE levels in the surrounding environment(sediment).Five wild trout species[rainbow trout(Oncorhynchus mykiss),brown trout(Salmo trutta),lake trout(Salvelinus namaycush),arctic char(Salvelinus alpinus),and brook trout(Salvelinus fontinalis)],collected worldwide within the 1994 to present time frame,were considered.Multivariate techniques(principal component analysis-PCA)and mapping approach,showed clear differences in geographic distribution patterns of PBDE levels in trout depending on the region studied:wild trout from European and North American great lakes have the highest PBDE loads.This pattern could be due to high industrial activity at these locations.A correlational approach used to explore intraspecific relationships between PBDE levels and morphometry,showed positive relationships only for brown trout.Further,brown trout showed the highest trout-to-sediment ratios,which is suggestive of a relatively greater capacity of this species to accumulate PBDEs in relation to sediment levels.Overall,results suggest that adult wild trout could be useful as a PBDE bioindicator.

Bio-ecological remediation of freshwater aquaculture environments:A systematic review and bibliometric analysis

Freshwater aquaculture plays an important role in the global aquaculture industry.The success of freshwater aquaculture relies on the integration of bio-ecological remediation technologies to ensure its sustainable development.This paper systematically reviews the global literatures on bio-ecological remediation of freshwater aquaculture environments from 1990 to 2021,and discusses in detail the research progress and status quo in this field using both bibliometric analysis and content analysis.Our results indicate that the number of publications per year has increased year by year,with a particularly rapid increase after 2015.Institutions and researchers from China and the USA publish the greatest number of papers and contribute the most to this field.By analyzing the research progress in this field,we also find that the protection and restoration of freshwater aquaculture environments has received attention since as early as 1990,such as the application of constructed wetlands and recirculating aquaculture systems.Recently,researchers have increasingly focused on the use of microbial communities in remediation.Furthermore,vanRijn,J's papers are of great value to the research in this field.In content analysis,the application of primary technologies,including plant selection,aquatic animals,microorganisms,and biological filtration and purification equipment,as well as ecological engineering technologies with combinations of various types of organisms,is described to improve the effectiveness and efficiency of remediation.The performance,advantages,disadvantages,or limitations and prospects of these technology applications are analyzed in detail.By comparison,ecological engineering is shown to be the best remediation technology,being most comprehensive,and well-established.Taken together,this paper composes and summarizes existing work in this field,and provides guidance for future research on the improvement of existing technologies and the development of new technologies,with the aim of enhancing remediation capability,improving ecological sustainability and ensuring economic viability.