Atlantic Meridional Overturning Circulation(AMOC)plays a central role in long-term climate variations through its heat and freshwater transports,which can collapse under a rapid increase of greenhouse gas forcing in c...Atlantic Meridional Overturning Circulation(AMOC)plays a central role in long-term climate variations through its heat and freshwater transports,which can collapse under a rapid increase of greenhouse gas forcing in climate models.Previous studies have suggested that the deviation of model parameters is one of the major factors in inducing inaccurate AMOC simulations.In this work,with a low-resolution earth system model,the authors try to explore whether a reasonable adjustment of the key model parameter can help to re-establish the AMOC after its collapse.Through a new optimization strategy,the extra freshwater flux(FWF)parameter is determined to be the dominant one affecting the AMOC’s variability.The traditional ensemble optimal interpolation(EnOI)data assimilation and new machine learning methods are adopted to optimize the FWF parameter in an abrupt 4×CO_(2) forcing experiment to improve the adaptability of model parameters and accelerate the recovery of AMOC.The results show that,under an abrupt 4×CO_(2) forcing in millennial simulations,the AMOC will first collapse and then re-establish by the default FWF parameter slowly.However,during the parameter adjustment process,the saltier and colder sea water over the North Atlantic region are the dominant factors in usefully improving the adaptability of the FWF parameter and accelerating the recovery of AMOC,according to their physical relationship with FWF on the interdecadal timescale.展开更多
The global rise in CO_(2)concentration is having a profound impact on the structure and function of aquatic ecosystems.However,little information is available on the responses of odorproducing cyanobacteria to the inc...The global rise in CO_(2)concentration is having a profound impact on the structure and function of aquatic ecosystems.However,little information is available on the responses of odorproducing cyanobacteria to the increase in CO_(2)concentration.In this study,the effects of different CO_(2)concentrations on 2-methylisoborneol(MIB)-producing Pseudanabaena and non-2-MIB-producing Pseudanabaena under monoculture and co-culture conditions were investigated.Results show that the specific growth rate of Pseudanabaena gradually increased with the rise in CO_(2)concentration,and for the 2-MIB-producing strain,this increase was significantly higher than the non-2-MIB-producing strain.Under co-culture conditions,the proportion of non-2-MIB-producing Pseudanabaena was significantly higher than that of 2-MIB-producing Pseudanabaena,suggesting a superior competitive ability of non-2-MIB-producing Pseudanabaena over 2-MIB-producing Pseudanabaena.Under monoculture conditions,the total 2-MIB production at the 300-μg/g CO_(2)concentration was significantly higher than that at 600-and 1200-μg/g CO_(2)concentrations.The 2-MIB concentration produced by Pseudanabaena decreased with the increasing in CO_(2)concentration.Therefore,we believe that with the future increase in CO_(2)concentration,2-MIB concentration would be decreased and so would the risk of 2-MIB outbreaks.展开更多
Allelochemicals of Chinese-fir root was extracted by technology ofsupercritical CO_2 extraction under orthogonal experiment design, and it was used to analyzeallelopathic activity of Chinese-fir through bioassay of se...Allelochemicals of Chinese-fir root was extracted by technology ofsupercritical CO_2 extraction under orthogonal experiment design, and it was used to analyzeallelopathic activity of Chinese-fir through bioassay of seed germination. The results showed thatas to the available rate of allelochemicals, the pressure and temperature of extraction were themost important factors. The allelochemicals of Chinese-fir root extracted by pure CO_2 and ethanolmixed with CO_2 have different allelopathic activities to seed germination, and the allelochemicalsextracted by ethanol mixed with CO_2 had stronger inhibitory effects on seed germination than thatextracted by pure CO_2.展开更多
基金supported by the National Key R&D Program of China [grant number 2023YFF0805202]the National Natural Science Foun-dation of China [grant number 42175045]the Strategic Priority Research Program of the Chinese Academy of Sciences [grant number XDB42000000]。
文摘Atlantic Meridional Overturning Circulation(AMOC)plays a central role in long-term climate variations through its heat and freshwater transports,which can collapse under a rapid increase of greenhouse gas forcing in climate models.Previous studies have suggested that the deviation of model parameters is one of the major factors in inducing inaccurate AMOC simulations.In this work,with a low-resolution earth system model,the authors try to explore whether a reasonable adjustment of the key model parameter can help to re-establish the AMOC after its collapse.Through a new optimization strategy,the extra freshwater flux(FWF)parameter is determined to be the dominant one affecting the AMOC’s variability.The traditional ensemble optimal interpolation(EnOI)data assimilation and new machine learning methods are adopted to optimize the FWF parameter in an abrupt 4×CO_(2) forcing experiment to improve the adaptability of model parameters and accelerate the recovery of AMOC.The results show that,under an abrupt 4×CO_(2) forcing in millennial simulations,the AMOC will first collapse and then re-establish by the default FWF parameter slowly.However,during the parameter adjustment process,the saltier and colder sea water over the North Atlantic region are the dominant factors in usefully improving the adaptability of the FWF parameter and accelerating the recovery of AMOC,according to their physical relationship with FWF on the interdecadal timescale.
基金Supported by the National Key R&D Program of China(No.2021YFC3200900)the National Natural Science Foundation of China(No.31971477)。
文摘The global rise in CO_(2)concentration is having a profound impact on the structure and function of aquatic ecosystems.However,little information is available on the responses of odorproducing cyanobacteria to the increase in CO_(2)concentration.In this study,the effects of different CO_(2)concentrations on 2-methylisoborneol(MIB)-producing Pseudanabaena and non-2-MIB-producing Pseudanabaena under monoculture and co-culture conditions were investigated.Results show that the specific growth rate of Pseudanabaena gradually increased with the rise in CO_(2)concentration,and for the 2-MIB-producing strain,this increase was significantly higher than the non-2-MIB-producing strain.Under co-culture conditions,the proportion of non-2-MIB-producing Pseudanabaena was significantly higher than that of 2-MIB-producing Pseudanabaena,suggesting a superior competitive ability of non-2-MIB-producing Pseudanabaena over 2-MIB-producing Pseudanabaena.Under monoculture conditions,the total 2-MIB production at the 300-μg/g CO_(2)concentration was significantly higher than that at 600-and 1200-μg/g CO_(2)concentrations.The 2-MIB concentration produced by Pseudanabaena decreased with the increasing in CO_(2)concentration.Therefore,we believe that with the future increase in CO_(2)concentration,2-MIB concentration would be decreased and so would the risk of 2-MIB outbreaks.
基金This paper was supported by Natural Science Foundation of Fujian Province (B0010020)
文摘Allelochemicals of Chinese-fir root was extracted by technology ofsupercritical CO_2 extraction under orthogonal experiment design, and it was used to analyzeallelopathic activity of Chinese-fir through bioassay of seed germination. The results showed thatas to the available rate of allelochemicals, the pressure and temperature of extraction were themost important factors. The allelochemicals of Chinese-fir root extracted by pure CO_2 and ethanolmixed with CO_2 have different allelopathic activities to seed germination, and the allelochemicalsextracted by ethanol mixed with CO_2 had stronger inhibitory effects on seed germination than thatextracted by pure CO_2.
