Environmental conditions are more effective than nutrient availability and spatial processes on explaining microphytoplankton functional structure in a subtropical hypereutrophic reservoir

2021 ◽  
Author(s):  
Jonatas Alves ◽  
Lorena Pinheiro‐Silva ◽  
Karling Fernanda Schuster ◽  
Alexandre Matthiensen ◽  
Mauricio Mello Petrucio
2019 ◽  
Author(s):  
Giulia Faucher ◽  
Ulf Riebesell ◽  
Lennart Thomas Bach

Abstract. Morphological changes in coccoliths, tiny calcite platelets covering the outer surface of coccolithophores, can be the result of physiological responses to environmental changes. Coccoliths recovered from sedimentary successions may therefore provide information on paleo-environmental conditions prevailing at the time when the coccolithophores were alive. To calibrate the biomineralization responses of ancient coccolithophore to climatic changes studies often compared the biological responses of living coccolithophore species with paleo-data from calcareous nannofossils. However, there is uncertainty whether the morphological responses of living coccolithophores are representative for those of the fossilized ancestors. To investigate this, we cultured four living coccolithophore species (Emiliania huxleyi, Gephyrocapsa oceanica, Coccolithus pelagicus subsp. braarudii, and Pleurochrysis carterae) that have been evolutionarily distinct for millions of years, exposed them to changing environmental conditions (i.e. changing light intensity, Mg / Ca ratio, nutrient availability, temperature and carbonate chemistry) and evaluated their responses in coccolith morphology (i.e. size, length, width, malformation). The motivation for this study was that if the species show the same morphological response to changes in any of the tested abiotic environmental factors, then there is a reason to assume that this response is conserved over geological timescales and that coccolith morphology can serve as a paleo-proxy for that specific factor. In contrast with this concept, we found that the four species responded differently to changing light intensity, Mg / Ca ratio, nutrient availability and temperature in terms of coccolith morphology. The lack of a common response reveals the difficulties in using coccolith morphology as a proxy for paleo-environmental conditions. However, a common response was observed under changing seawater carbonate chemistry (i.e. rising CO2) which consistently induced malformations. This commonality provides some confidence that malformations found in the sedimentary record could be indicative for high CO2 levels.


2017 ◽  
Author(s):  
Wenfa Ng

Temperature rise from climate change may completely change geological landscapes and environmental conditions at habitats previously conducive for specific animal species. Together with increasing difficulty in coping with greater fluctuations in temperature between seasons as well as reduced or enhanced precipitations in areas normally accustomed to consistent patterns of rainfall, variation in nutrient availability is another significant factor impacting on the survivability of animals in a specific area, particularly those in the mid-latitudes and on mountain slopes. Thus, prompted by the lack of nutrients or availability of water arising from climatic changes, many warm and cold-blooded species may migrate towards polar regions as well as higher altitudes of mountains in search of more habitable conditions. Such migrations open up myriad research opportunities into understanding how predators and prey adapt to changes in environmental factors and nutrient availability under climate change, which is accelerating in the polar regions. Specifically, predators and prey may differentially move to different locales with predators having to adapt to new food sources or change their foraging patterns, which, in turn, may impact on their social behaviours on parenting and hunting habits. An example would be lack of food sources prompting predators high in the food chain to adapt by having fewer offsprings, switching to available but less nutritious food, as well as changing foraging patterns. On the other hand, prey may use changes in geological formations between habitats to adapt their breeding patterns as well as foraging activities; for example, using camouflage available in the new environment to better protect their young from new and old predators. Similarly, species on the vertical transect of mountains would also move to higher altitudes to adapt to heat from global warming, or execute a poleward movement in search of more conducive habitats. Altogether, many interesting research directions are awaiting exploration as animal species move towards the poles or higher altitudes on mountains, prompted by rising temperatures that changed environmental conditions and nutrient availability. Mass migrations such as these may potentially unsettle entire ecosystems as species able to adapt to higher temperatures benefit from reduced competition, while those choosing the migratory path face an uncertain future in finding a habitable niche similar to the abandoned one, as well as ability to adapt to the new locale in foraging behaviour, breeding patterns and social behaviour. Possible changes in social behaviour is one significant area for understanding how climate change induced migration exert a selection pressure on animal behaviour and neural development. Interested researchers can expand on the ideas presented in this abstract preprint.


2017 ◽  
Vol 28 (4) ◽  
pp. 871-881 ◽  
Author(s):  
Maria Prieto ◽  
Isabel Martínez ◽  
Gregorio Aragón ◽  
Miguel Verdú

2021 ◽  
Vol 12 ◽  
Author(s):  
Jelena Pavlovic ◽  
Ljiljana Kostic ◽  
Predrag Bosnic ◽  
Ernest A. Kirkby ◽  
Miroslav Nikolic

Silicon (Si) is not classified as an essential element for plants, but numerous studies have demonstrated its beneficial effects in a variety of species and environmental conditions, including low nutrient availability. Application of Si shows the potential to increase nutrient availability in the rhizosphere and root uptake through complex mechanisms, which still remain unclear. Silicon-mediated transcriptional regulation of element transporters for both root acquisition and tissue homeostasis has recently been suggested as an important strategy, varying in detail depending on plant species and nutritional status. Here, we summarize evidence of Si-mediated acquisition, uptake and translocation of nutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), boron (B), chlorine (Cl), and nickel (Ni) under both deficiency and excess conditions. In addition, we discuss interactions of Si-with beneficial elements: aluminum (Al), sodium (Na), and selenium (Se). This review also highlights further research needed to improve understanding of Si-mediated acquisition and utilization of nutrients and vice versa nutrient status-mediated Si acquisition and transport, both processes which are of high importance for agronomic practice (e.g., reduced use of fertilizers and pesticides).


2017 ◽  
Author(s):  
Wenfa Ng

Temperature rise from climate change may completely change geological landscapes and environmental conditions at habitats previously conducive for specific animal species. Together with increasing difficulty in coping with greater fluctuations in temperature between seasons as well as reduced or enhanced precipitations in areas normally accustomed to consistent patterns of rainfall, variation in nutrient availability is another significant factor impacting on the survivability of animals in a specific area, particularly those in the mid-latitudes and on mountain slopes. Thus, prompted by the lack of nutrients or availability of water arising from climatic changes, many warm and cold-blooded species may migrate towards polar regions as well as higher altitudes of mountains in search of more habitable conditions. Such migrations open up myriad research opportunities into understanding how predators and prey adapt to changes in environmental factors and nutrient availability under climate change, which is accelerating in the polar regions. Specifically, predators and prey may differentially move to different locales with predators having to adapt to new food sources or change their foraging patterns, which, in turn, may impact on their social behaviours on parenting and hunting habits. An example would be lack of food sources prompting predators high in the food chain to adapt by having fewer offsprings, switching to available but less nutritious food, as well as changing foraging patterns. On the other hand, prey may use changes in geological formations between habitats to adapt their breeding patterns as well as foraging activities; for example, using camouflage available in the new environment to better protect their young from new and old predators. Similarly, species on the vertical transect of mountains would also move to higher altitudes to adapt to heat from global warming, or execute a poleward movement in search of more conducive habitats. Altogether, many interesting research directions are awaiting exploration as animal species move towards the poles or higher altitudes on mountains, prompted by rising temperatures that changed environmental conditions and nutrient availability. Mass migrations such as these may potentially unsettle entire ecosystems as species able to adapt to higher temperatures benefit from reduced competition, while those choosing the migratory path face an uncertain future in finding a habitable niche similar to the abandoned one, as well as ability to adapt to the new locale in foraging behaviour, breeding patterns and social behaviour. Possible changes in social behaviour is one significant area for understanding how climate change induced migration exert a selection pressure on animal behaviour and neural development. Interested researchers can expand on the ideas presented in this abstract preprint.


2017 ◽  
Vol 16 (2) ◽  
pp. 209-227 ◽  
Author(s):  
Frida Güiza ◽  
Yadira Méndez–Lemus ◽  
Michael K. McCall

Urbanscapes of disaster are socially and environmentally constituted. Drawing upon the theoretical framework of social vulnerability to disasters, the concept of urbanscape is enriched and empirically verified. This paper highlights how urban social hazards are more relevant for vulnerable people than the risk of experiencing the negative effects of extreme natural events. The analysis of floods in a slum located in a Mexican city reveals intricate socioenvironmental conditions underpinning a disaster process. Findings reveal that social, political, and economic hazards (including criminal hazards), imposed by the urban model on its inhabitants, are the most difficult to cope with and adapt to. This paper contributes to the wider literature on disasters, presenting an in–depth qualitative analysis of the factors propelling urban dwellers to endure in a vulnerable urbanscape, regardless of the physical and environmental conditions at the site.


2020 ◽  
Vol 16 (3) ◽  
pp. 1007-1025 ◽  
Author(s):  
Giulia Faucher ◽  
Ulf Riebesell ◽  
Lennart Thomas Bach

Abstract. Morphological changes in coccoliths, tiny calcite platelets covering the outer surface of coccolithophores, can be induced by physiological responses to environmental changes. Coccoliths recovered from sedimentary successions may therefore provide information on paleo-environmental conditions prevailing at the time when the coccolithophores were alive. To calibrate the biomineralization responses of ancient coccolithophore to environmental changes, studies often compared the biological responses of living coccolithophore species with paleo-data from calcareous nannofossils. However, there is uncertainty whether the morphological responses of living coccolithophores are representative of those of the fossilized ancestors. To investigate this, we exposed four living coccolithophore species (Emiliania huxleyi, Gephyrocapsa oceanica, Coccolithus pelagicus subsp. braarudii, and Pleurochrysis carterae) that have been evolutionarily distinct for hundreds of thousands to millions of years, to a range of environmental conditions (i.e., changing light intensity, Mg∕Ca ratio, nutrient availability, temperature, and carbonate chemistry) and evaluated their responses in coccolith morphology (i.e., size, length, width, malformation). The motivation for this study was to test if there is a consistent morphological response of the four species to changes in any of the tested abiotic environmental factors. If this was the case, then this could suggest that coccolith morphology can serve as a paleo-proxy for that specific factor because this response is conserved across species that have been evolutionary distinct over geological timescales. However, we found that the four species responded differently to changing light intensity, Mg∕Ca ratio, nutrient availability, and temperature in terms of coccolith morphology. The lack of a common response reveals the difficulties in using coccolith morphology as a paleo-proxy for these environmental drivers. However, a common response was observed under changing seawater carbonate chemistry (i.e., rising CO2), which consistently induced malformations. This commonality provides some confidence that malformations found in the sedimentary record could be indicative of adverse carbonate chemistry conditions.


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