The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform
Chenxi Wu - One of the best experts on this subject based on the ideXlab platform.
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Sinking of floating plastic debris caused by biofilm development in a freshwater lake
Chemosphere, 2019Co-Authors: Xianchuan Chen, Xiong Xiong, Xiaoming Jiang, Huahong Shi, Chenxi WuAbstract:Abstract Plastic pollution has been increasingly reported in both marine environment and inland waters, but their fate is not well understood. Several studies have showed that the surface of plastic debris can be colonized by microbes, leading to the sinking of floating plastic debris in marine environment. In this work, development of biofilm on polypropylene sheet (squares with a side length of 5 and 10 mm) and their Buoyancy changes were studied in a freshwater lake in four seasons. Results showed that biofilm development have different growth rate and distinct algae composition in different seasons, which are mainly related to the difference in temperature, nutrient levels, and suspend solids in lake water. Biofilm development was much quicker on small plastics in all seasons. At the end of the experiment, all plastics Lost Buoyancy in summer while only a small portion Lost buoyance in other seasons. Sinking of the floating plastics can be attributed to the development of biofilm and the trapped minerals. Our results demonstrated that biofilm development can cause the sinking of floating plastics in fresh lakes but the time required to lose buoyance can differ seasonally. Floating plastics will remain in water for a longer time in cold season but sink in a short time in warm season. Future research is required to determine the influence of plastic types and shapes, and quantitative relation between environmental variables and the sinking behavior of the fouled plastics should be established for a better prediction of their fate in the freshwater environment.
Martin Schmid - One of the best experts on this subject based on the ideXlab platform.
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The Burgundy-blood phenomenon: a model of Buoyancy change explains autumnal waterblooms by Planktothrix rubescens in Lake Zürich
The New phytologist, 2006Co-Authors: Anthony E. Walsby, Ferdinand Schanz, Martin SchmidAbstract:Summary • Buoyancy changes of the cyanobacterium Planktothrix rubescens– the Burgundy-blood alga – were modelled from its Buoyancy response to light and irradiance changes in Lake Zurich during autumnal mixing. • The daily insolation received by filaments at fixed depths and circulating to different depths was calculated from the measured light attenuation and surface irradiance. The active mixing depth, za5, was determined from the vertical turbulent diffusion coefficient, Kz, calculated from the wind speed, heat flux and temperature gradients. The fixed depth resulting in filament Buoyancy, zn, decreased from 13 to 2 m between August and December 1998; the critical depth for Buoyancy, zq, to which filaments must be circulated to become buoyant, decreased from >60 m in the summer to za5: circulating filaments would have Lost Buoyancy in the high insolation. Often in November and December, after deeper mixing and lower insolation, za5 > zq: filaments would have become buoyant but would have floated to the lake surface (the Burgundy-blood phenomenon) only under subsequent calm conditions, when Kz was low. • The model explains the Burgundy-blood phenomenon in deeper lakes; waterblooms near shallow leeward shores arise from populations floating up in deeper regions of the lake.
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the burgundy blood phenomenon a model of Buoyancy change explains autumnal waterblooms by planktothrix rubescens in lake zurich
New Phytologist, 2006Co-Authors: A. E. Walsby, Ferdinand Schanz, Martin SchmidAbstract:Summary • Buoyancy changes of the cyanobacterium Planktothrix rubescens– the Burgundy-blood alga – were modelled from its Buoyancy response to light and irradiance changes in Lake Zurich during autumnal mixing. • The daily insolation received by filaments at fixed depths and circulating to different depths was calculated from the measured light attenuation and surface irradiance. The active mixing depth, za5, was determined from the vertical turbulent diffusion coefficient, Kz, calculated from the wind speed, heat flux and temperature gradients. The fixed depth resulting in filament Buoyancy, zn, decreased from 13 to 2 m between August and December 1998; the critical depth for Buoyancy, zq, to which filaments must be circulated to become buoyant, decreased from >60 m in the summer to <10 m in winter. • When za5 first exceeded zn, in September, P. rubescens was mixed into the epilimnion. In October, zq > za5: circulating filaments would have Lost Buoyancy in the high insolation. Often in November and December, after deeper mixing and lower insolation, za5 > zq: filaments would have become buoyant but would have floated to the lake surface (the Burgundy-blood phenomenon) only under subsequent calm conditions, when Kz was low. • The model explains the Burgundy-blood phenomenon in deeper lakes; waterblooms near shallow leeward shores arise from populations floating up in deeper regions of the lake.
Xianchuan Chen - One of the best experts on this subject based on the ideXlab platform.
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Sinking of floating plastic debris caused by biofilm development in a freshwater lake
Chemosphere, 2019Co-Authors: Xianchuan Chen, Xiong Xiong, Xiaoming Jiang, Huahong Shi, Chenxi WuAbstract:Abstract Plastic pollution has been increasingly reported in both marine environment and inland waters, but their fate is not well understood. Several studies have showed that the surface of plastic debris can be colonized by microbes, leading to the sinking of floating plastic debris in marine environment. In this work, development of biofilm on polypropylene sheet (squares with a side length of 5 and 10 mm) and their Buoyancy changes were studied in a freshwater lake in four seasons. Results showed that biofilm development have different growth rate and distinct algae composition in different seasons, which are mainly related to the difference in temperature, nutrient levels, and suspend solids in lake water. Biofilm development was much quicker on small plastics in all seasons. At the end of the experiment, all plastics Lost Buoyancy in summer while only a small portion Lost buoyance in other seasons. Sinking of the floating plastics can be attributed to the development of biofilm and the trapped minerals. Our results demonstrated that biofilm development can cause the sinking of floating plastics in fresh lakes but the time required to lose buoyance can differ seasonally. Floating plastics will remain in water for a longer time in cold season but sink in a short time in warm season. Future research is required to determine the influence of plastic types and shapes, and quantitative relation between environmental variables and the sinking behavior of the fouled plastics should be established for a better prediction of their fate in the freshwater environment.
Xiong Xiong - One of the best experts on this subject based on the ideXlab platform.
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Sinking of floating plastic debris caused by biofilm development in a freshwater lake
Chemosphere, 2019Co-Authors: Xianchuan Chen, Xiong Xiong, Xiaoming Jiang, Huahong Shi, Chenxi WuAbstract:Abstract Plastic pollution has been increasingly reported in both marine environment and inland waters, but their fate is not well understood. Several studies have showed that the surface of plastic debris can be colonized by microbes, leading to the sinking of floating plastic debris in marine environment. In this work, development of biofilm on polypropylene sheet (squares with a side length of 5 and 10 mm) and their Buoyancy changes were studied in a freshwater lake in four seasons. Results showed that biofilm development have different growth rate and distinct algae composition in different seasons, which are mainly related to the difference in temperature, nutrient levels, and suspend solids in lake water. Biofilm development was much quicker on small plastics in all seasons. At the end of the experiment, all plastics Lost Buoyancy in summer while only a small portion Lost buoyance in other seasons. Sinking of the floating plastics can be attributed to the development of biofilm and the trapped minerals. Our results demonstrated that biofilm development can cause the sinking of floating plastics in fresh lakes but the time required to lose buoyance can differ seasonally. Floating plastics will remain in water for a longer time in cold season but sink in a short time in warm season. Future research is required to determine the influence of plastic types and shapes, and quantitative relation between environmental variables and the sinking behavior of the fouled plastics should be established for a better prediction of their fate in the freshwater environment.
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Sinking of floating plastic debris caused by biofilm development in a freshwater lake
'Elsevier BV', 2019Co-Authors: Chen Xianchuan, Xiong Xiong, Jiang Xiaoming, Shi Huahong, Wu ChenxiAbstract:Plastic pollution has been increasingly reported in both marine environment and inland waters, but their fate is not well understood. Several studies have showed that the surface of plastic debris can be colonized by microbes, leading to the sinking of floating plastic debris in marine environment. In this work, development of biofilm on polypropylene sheet (squares with a side length of 5 and 10 mm) and their Buoyancy changes were studied in a freshwater lake in four seasons. Results showed that biofilm development have different growth rate and distinct algae composition in different seasons, which are mainly related to the difference in temperature, nutrient levels, and suspend solids in lake water. Biofilm development was much quicker on small plastics in all seasons. At the end of the experiment, all plastics Lost Buoyancy in summer while only a small portion Lost buoyance in other seasons. Sinking of the floating plastics can be attributed to the development of biofilm and the trapped minerals. Our results demonstrated that biofilm development can cause the sinking of floating plastics in fresh lakes but the time required to lose buoyance can differ seasonally. Floating plastics will remain in water for a longer time in cold season but sink in a short time in warm season. Future research is required to determine the influence of plastic types and shapes, and quantitative relation between environmental variables and the sinking behavior of the fouled plastics should be established for a better prediction of their fate in the freshwater environment. (C) 2019 Elsevier Ltd. All rights reserved
Peter G Ryan - One of the best experts on this subject based on the ideXlab platform.
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biofouling on buoyant marine plastics an experimental study into the effect of size on surface longevity
Environmental Pollution, 2016Co-Authors: Francesca M C Fazey, Peter G RyanAbstract:Recent estimates suggest that roughly 100 times more plastic litter enters the sea than is found floating at the sea surface, despite the Buoyancy and durability of many plastic polymers. Biofouling by marine biota is one possible mechanism responsible for this discrepancy. Microplastics (<5 mm in diameter) are more scarce than larger size classes, which makes sense because fouling is a function of surface area whereas Buoyancy is a function of volume; the smaller an object, the greater its relative surface area. We tested whether plastic items with high surface area to volume ratios sank more rapidly by submerging 15 different sizes of polyethylene samples in False Bay, South Africa, for 12 weeks to determine the time required for samples to sink. All samples became sufficiently fouled to sink within the study period, but small samples Lost Buoyancy much faster than larger ones. There was a direct relationship between sample volume (Buoyancy) and the time to attain a 50% probability of sinking, which ranged from 17 to 66 days of exposure. Our results provide the first estimates of the longevity of different sizes of plastic debris at the ocean surface. Further research is required to determine how fouling rates differ on free floating debris in different regions and in different types of marine environments. Such estimates could be used to improve model predictions of the distribution and abundance of floating plastic debris globally.
