2017 Vol. 36, No. 2
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2017, 36(2): .
Abstract:
2017, 36(2): 1-10.
doi: 10.1007/s13131-017-0981-7
Abstract:
The Hangzhou Bay (HZB) and Xiangshan Bay (XSB), in northern Zhejiang Province and connect to the East China Sea (ECS) were considerably affected by the consequence of water quality degradation. In this study, we analyzed physical and biogeochemical properties of water quality via multivariate statistical techniques. Hierarchical cluster analysis (HCA) grouped HZB and XSB into two subareas of different pollution sources based on similar physical and biogeochemical properties. Principal component analysis (PCA) identified three latent pollution sources in HZB and XSB respectively and emphasized the importance of terrestrial inputs, coastal industries as well as natural processes in determining the water quality of the two bays. Therefore, proper measurement for the protection of aquatic ecoenvironment in HZB and XSB were of great urgency.
The Hangzhou Bay (HZB) and Xiangshan Bay (XSB), in northern Zhejiang Province and connect to the East China Sea (ECS) were considerably affected by the consequence of water quality degradation. In this study, we analyzed physical and biogeochemical properties of water quality via multivariate statistical techniques. Hierarchical cluster analysis (HCA) grouped HZB and XSB into two subareas of different pollution sources based on similar physical and biogeochemical properties. Principal component analysis (PCA) identified three latent pollution sources in HZB and XSB respectively and emphasized the importance of terrestrial inputs, coastal industries as well as natural processes in determining the water quality of the two bays. Therefore, proper measurement for the protection of aquatic ecoenvironment in HZB and XSB were of great urgency.
2017, 36(2): 11-21.
doi: 10.1007/s13131-016-0849-2
Abstract:
Mangrove degradation must reduce carbon sequestration in recent years, thereby aggravating global warming. Thus, short-term impacts of human activity on mangrove ecosystems are cause for concern from local governments and scientists. Mangroves sediments can provide detailed records of mangrove species variation in the last one hundred years, based on detailed 210Pb data. The study traced the history of mangrove development and its response to environmental change over the last 140 years in two mangrove swamps of Guangxi, Southwest China. Average sedimentation rates were calculated to be 0.48 cm/a and 0.56 cm/a in the Yingluo Bay and the Maowei Sea, respectively. Chemical indicators (δ13Corg and C:N) were utilized to trace the contribution of mangrove-derived organic matter (MOM) using a ternary mixing model. Simultaneous use of mangrove pollen can help to supplement some of these limitations in diagenetic/overlap of isotopic signatures. We found that vertical distribution of MOM was consistent with mangrove pollen, which could provide similar information for tracing mangrove ecosystems. Therefore, mangrove development was reconstructed and divided into three stages:flourishing, degradation and re-flourishing/re-degradation period. The significant degradation, found in the period of 1968-1998 and 1907-2007 in the Yingluo Bay and the Maowei Sea, respectively, corresponding to a rapid increase of reclamation area and seawall length, rather than climate change as recorded in the region.
Mangrove degradation must reduce carbon sequestration in recent years, thereby aggravating global warming. Thus, short-term impacts of human activity on mangrove ecosystems are cause for concern from local governments and scientists. Mangroves sediments can provide detailed records of mangrove species variation in the last one hundred years, based on detailed 210Pb data. The study traced the history of mangrove development and its response to environmental change over the last 140 years in two mangrove swamps of Guangxi, Southwest China. Average sedimentation rates were calculated to be 0.48 cm/a and 0.56 cm/a in the Yingluo Bay and the Maowei Sea, respectively. Chemical indicators (δ13Corg and C:N) were utilized to trace the contribution of mangrove-derived organic matter (MOM) using a ternary mixing model. Simultaneous use of mangrove pollen can help to supplement some of these limitations in diagenetic/overlap of isotopic signatures. We found that vertical distribution of MOM was consistent with mangrove pollen, which could provide similar information for tracing mangrove ecosystems. Therefore, mangrove development was reconstructed and divided into three stages:flourishing, degradation and re-flourishing/re-degradation period. The significant degradation, found in the period of 1968-1998 and 1907-2007 in the Yingluo Bay and the Maowei Sea, respectively, corresponding to a rapid increase of reclamation area and seawall length, rather than climate change as recorded in the region.
2017, 36(2): 22-34.
doi: 10.1007/s13131-016-0961-3
Abstract:
A seafloor hydrothermal field, named Deyin-1 later, near 15°S southern Mid-Atlantic Ridge (SMAR) was newly found during the 22nd cruise carried out by the China Ocean Mineral Resources Research & Development Association (COMRA). Sulfide samples were collected at three stations from the hydrothermal field during the 26th cruise in 2012. In this paper, mineralogical characteristics of the sulfides were analyzed with optical microscope, X-ray diffractometer, scanning electron microscope and electron microprobe to study the crystallization sequence of minerals and the process of hydrothermal mineralization. According to the difference of the ore-forming metal elements, the sulfide samples can be divided into three types:(1) the Fe-rich sulfide, which contains mainly pyrite and chalcopyrite; (2) the Fe-Cu-rich sulfide consisting predominantly of pyrite, chalcopyrite and isocubanite, with lesser amount of sphalerite, marmatite and pyrrhotine; and (3) the Fe-Zn-rich sulfide dominated by pyrite, sphalerite and marmatite, with variable amounts of chalcopyrite, isocubanite, pyrrhotine, marcasite, galena and gratonite. Mineral precipitations in these sulfides are in the sequence of chalcopyrite (isocubanite and possible coarse pyrite), fine pyrite, sphalerite (marmatite), galena, gratonite and then the minerals out of the dissolution. Two morphologically distinct generations (Py-I and Py-II) of pyrite are identified in each of the samples; inclusions of marmatite tend to exist in the coarse pyrite crystals (Py-I). Sphalerite in the Fe-Zn-rich sulfide is characterized by a "chalcopyrite disease" phenomenon. Mineral paragenetic relationships and a wide range of chemical compositions suggest that the environment of hydrothermal mineralization was largely changing. By comparison, the Fe-rich sulfide was formed in a relatively stable environment with a high temperature, but the conditions for the formation of the Fe-Cu-rich sulfide were variable. The Fe-Zn-rich sulfide was precipitated during the hydrothermal venting at relatively low temperature.
A seafloor hydrothermal field, named Deyin-1 later, near 15°S southern Mid-Atlantic Ridge (SMAR) was newly found during the 22nd cruise carried out by the China Ocean Mineral Resources Research & Development Association (COMRA). Sulfide samples were collected at three stations from the hydrothermal field during the 26th cruise in 2012. In this paper, mineralogical characteristics of the sulfides were analyzed with optical microscope, X-ray diffractometer, scanning electron microscope and electron microprobe to study the crystallization sequence of minerals and the process of hydrothermal mineralization. According to the difference of the ore-forming metal elements, the sulfide samples can be divided into three types:(1) the Fe-rich sulfide, which contains mainly pyrite and chalcopyrite; (2) the Fe-Cu-rich sulfide consisting predominantly of pyrite, chalcopyrite and isocubanite, with lesser amount of sphalerite, marmatite and pyrrhotine; and (3) the Fe-Zn-rich sulfide dominated by pyrite, sphalerite and marmatite, with variable amounts of chalcopyrite, isocubanite, pyrrhotine, marcasite, galena and gratonite. Mineral precipitations in these sulfides are in the sequence of chalcopyrite (isocubanite and possible coarse pyrite), fine pyrite, sphalerite (marmatite), galena, gratonite and then the minerals out of the dissolution. Two morphologically distinct generations (Py-I and Py-II) of pyrite are identified in each of the samples; inclusions of marmatite tend to exist in the coarse pyrite crystals (Py-I). Sphalerite in the Fe-Zn-rich sulfide is characterized by a "chalcopyrite disease" phenomenon. Mineral paragenetic relationships and a wide range of chemical compositions suggest that the environment of hydrothermal mineralization was largely changing. By comparison, the Fe-rich sulfide was formed in a relatively stable environment with a high temperature, but the conditions for the formation of the Fe-Cu-rich sulfide were variable. The Fe-Zn-rich sulfide was precipitated during the hydrothermal venting at relatively low temperature.
2017, 36(2): 35-42.
doi: 10.1007/s13131-017-1002-6
Abstract:
The United Nations Convention on the Law of the Sea entitled the coastal States to naturally extend the continental shelf, which has caused more drastic disputes of maritime delimitation. This paper devotes to clarifying the significant concept of natural prolongation through an effect method combing the legal principles and technical analysis. Firstly, the classic samples with respect of the development of geological features are traced. Based on these samples, the classification with a model is proposed in order to affirm the concept's significance under certain geomorphologic situations. Lastly, scientific analysis is used to present two potential prolongation situations and emphasize that all the technical analysis on maritime delimitation should be complied with international law and protect the common interest of all the mankind.
The United Nations Convention on the Law of the Sea entitled the coastal States to naturally extend the continental shelf, which has caused more drastic disputes of maritime delimitation. This paper devotes to clarifying the significant concept of natural prolongation through an effect method combing the legal principles and technical analysis. Firstly, the classic samples with respect of the development of geological features are traced. Based on these samples, the classification with a model is proposed in order to affirm the concept's significance under certain geomorphologic situations. Lastly, scientific analysis is used to present two potential prolongation situations and emphasize that all the technical analysis on maritime delimitation should be complied with international law and protect the common interest of all the mankind.
2017, 36(2): 43-50.
doi: 10.1007/s13131-017-1003-5
Abstract:
Mean trophic level of fishery landings (MTL) is one of the most widely used biodiversity indicators to assess the impacts of fishing. Based on the landing data compiled by Food and Agriculture Organization combined with trophic information of relevant species in FishBase, we evaluated the status of marine fisheries from 1950 to 2010 for different coastal states in Pacific, Atlantic and Indian Oceans. We found that the phenomenon of "fishing down marine food webs" occurred in 43 states. Specifically, 27 states belonged to "fishing-through" pattern, and 16 states resulted from "fishing-down" scenario. The sign of recovery in MTL was common in the Pacific, Atlantic and Indian Oceans (occurred in 20 states), but was generally accompanied by significantly decreased catches of traditional low trophic level species. In particular, 11 states showed significant declining catches of lower trophic levels. The MTL-based assessment of "fishing down marine food webs" needs to be interpreted cautiously.
Mean trophic level of fishery landings (MTL) is one of the most widely used biodiversity indicators to assess the impacts of fishing. Based on the landing data compiled by Food and Agriculture Organization combined with trophic information of relevant species in FishBase, we evaluated the status of marine fisheries from 1950 to 2010 for different coastal states in Pacific, Atlantic and Indian Oceans. We found that the phenomenon of "fishing down marine food webs" occurred in 43 states. Specifically, 27 states belonged to "fishing-through" pattern, and 16 states resulted from "fishing-down" scenario. The sign of recovery in MTL was common in the Pacific, Atlantic and Indian Oceans (occurred in 20 states), but was generally accompanied by significantly decreased catches of traditional low trophic level species. In particular, 11 states showed significant declining catches of lower trophic levels. The MTL-based assessment of "fishing down marine food webs" needs to be interpreted cautiously.
2017, 36(2): 51-56.
doi: 10.1007/s13131-017-0982-6
Abstract:
Sagittal otoliths morphology were compared to identify five Pampus species of the Chinese coast (Chinese pomfret Pampus chinensis, grey pomfret P. cinereus, southern lesser pomfret P. minor, plumage pomfret P. punctatissmus, and Pampus sp.). Otoliths demonstrated species-specific characteristics with noticeable differences in overall shape, margin and anterior region among species. With species divergence, otoliths get thinner following further developed rostrum and anti-rostrum. Interspecies variation in otolith could associate with experienced different temperature and water column. The discriminant analysis presented a high classification accuracy of 96.6%, which confirms the inter-specific distinction of otolith shape and enable the species identification.
Sagittal otoliths morphology were compared to identify five Pampus species of the Chinese coast (Chinese pomfret Pampus chinensis, grey pomfret P. cinereus, southern lesser pomfret P. minor, plumage pomfret P. punctatissmus, and Pampus sp.). Otoliths demonstrated species-specific characteristics with noticeable differences in overall shape, margin and anterior region among species. With species divergence, otoliths get thinner following further developed rostrum and anti-rostrum. Interspecies variation in otolith could associate with experienced different temperature and water column. The discriminant analysis presented a high classification accuracy of 96.6%, which confirms the inter-specific distinction of otolith shape and enable the species identification.
2017, 36(2): 57-61.
doi: 10.1007/s13131-017-1001-7
Abstract:
Bifenthrin (BF) is a pyrethroid insecticide that is widely used in agriculture, horticulture, and for residential purposes. However, few studies addressing the reproductive toxicity of BF on fishes are available. The present study was conducted to investigate the effects of BF on testicular development in Sebastiscus marmoratus and to gain insight into its mechanism. After exposure to 1, 10 and 100 ng/L BF for 50 days, there was a reduced number of mature sperm and an abundance of the late stages of spermatocysts in the testes. The levels of 17β-estradiol and testosterone were decreased significantly after BF exposure. The activity of caspase-3 was increased in a dose-dependent manner after BF exposure, TUNEL assay indicated that BF exposure resulted in the occurrence of apoptosis in the testes, which might be main reason for the inhibition of spermatogenesis.
Bifenthrin (BF) is a pyrethroid insecticide that is widely used in agriculture, horticulture, and for residential purposes. However, few studies addressing the reproductive toxicity of BF on fishes are available. The present study was conducted to investigate the effects of BF on testicular development in Sebastiscus marmoratus and to gain insight into its mechanism. After exposure to 1, 10 and 100 ng/L BF for 50 days, there was a reduced number of mature sperm and an abundance of the late stages of spermatocysts in the testes. The levels of 17β-estradiol and testosterone were decreased significantly after BF exposure. The activity of caspase-3 was increased in a dose-dependent manner after BF exposure, TUNEL assay indicated that BF exposure resulted in the occurrence of apoptosis in the testes, which might be main reason for the inhibition of spermatogenesis.
2017, 36(2): 62-68.
doi: 10.1007/s13131-016-0942-6
Abstract:
The aim of the present study is to detect the potential of the base population from diallel crosses of eight introduced strains of the Pacific white shrimp (Litopenaeus vannamei) for improving the yield. Heterosis and heritability were estimated for pond survival at commercial farm conditions for the base population that included 207 full-sib families from a nested mating design by artificial insemination. Among all the hybrids, the heterosis ranged from -11.37% (UA1×UA2) to 20.53% (UA3×SIN) with an average of 0.953%. The results showed that more than half of the hybrids (51.85%) have negative heterosis for survival rate, but most of the hybrids with positive heterosis have high estimates. The high proportion of negative heterosis for survival rate reminders us that the survival trait also should be considered in the crossbreeding program to avoid yield decrease. However, high positive heterosis manifested in most of the hybrids for survival indicates the usefulness of these hybrids for improving the survival to obtain higher yield by crossbreeding in this breeding program. The heritability estimate for pond survival was 0.092±0.043 when genetic groups were included in the pedigree, and it was significantly different from zero (P<0.05). The results from this study also indicated that significant improvement for survival is possible through selection in L. vannamei.
The aim of the present study is to detect the potential of the base population from diallel crosses of eight introduced strains of the Pacific white shrimp (Litopenaeus vannamei) for improving the yield. Heterosis and heritability were estimated for pond survival at commercial farm conditions for the base population that included 207 full-sib families from a nested mating design by artificial insemination. Among all the hybrids, the heterosis ranged from -11.37% (UA1×UA2) to 20.53% (UA3×SIN) with an average of 0.953%. The results showed that more than half of the hybrids (51.85%) have negative heterosis for survival rate, but most of the hybrids with positive heterosis have high estimates. The high proportion of negative heterosis for survival rate reminders us that the survival trait also should be considered in the crossbreeding program to avoid yield decrease. However, high positive heterosis manifested in most of the hybrids for survival indicates the usefulness of these hybrids for improving the survival to obtain higher yield by crossbreeding in this breeding program. The heritability estimate for pond survival was 0.092±0.043 when genetic groups were included in the pedigree, and it was significantly different from zero (P<0.05). The results from this study also indicated that significant improvement for survival is possible through selection in L. vannamei.
2017, 36(2): 69-77.
doi: 10.1007/s13131-016-0962-2
Abstract:
Microbial carbon fixation is a paramount process in the ocean especially below the photic zone both in water and sedimentary ecosystems. Autotrophic microbes that fix carbon dioxide are renowned. However, the question whether heterotrophs can also fix carbon is intriguing. Ten heterotrophically grown, identified bacterial isolates from the Sino-Pacific marine sediments were tested for autotrophic uptake potential with and without addition of electron donors. Nine of the ten isolates showed carbon uptake capacity without addition of any substrate at very low rates in the order of 10-8 to 10-4 fmol/(cell·h). The addition of manganese and ammonium at 1 mmol/L final concentration enhanced the uptake potential. Addition of 1 mmol/L final concentrations of reduced iron (10-6 to 10-5 fmol/(cell·h) and sulfide (10-5 fmol/(cell·h) decreased the uptake potential significantly at p<0.1. Bacterial tolerance to formaldehyde suggested propensities of anaplerotic chemical reactions that form metabolic intermediates of C-1 metabolism pathways. The isolates displayed high metabolic flexibility. With the changes in electron donors, the isolates metabolically toggled between relatively anoxic reductive iron/sulfur cycles and the oxidative cycles of manganese/ammonium and vice-versa. This property makes these microbes successful survivors in the highly dynamic Sino-Pacific sediments.
Microbial carbon fixation is a paramount process in the ocean especially below the photic zone both in water and sedimentary ecosystems. Autotrophic microbes that fix carbon dioxide are renowned. However, the question whether heterotrophs can also fix carbon is intriguing. Ten heterotrophically grown, identified bacterial isolates from the Sino-Pacific marine sediments were tested for autotrophic uptake potential with and without addition of electron donors. Nine of the ten isolates showed carbon uptake capacity without addition of any substrate at very low rates in the order of 10-8 to 10-4 fmol/(cell·h). The addition of manganese and ammonium at 1 mmol/L final concentration enhanced the uptake potential. Addition of 1 mmol/L final concentrations of reduced iron (10-6 to 10-5 fmol/(cell·h) and sulfide (10-5 fmol/(cell·h) decreased the uptake potential significantly at p<0.1. Bacterial tolerance to formaldehyde suggested propensities of anaplerotic chemical reactions that form metabolic intermediates of C-1 metabolism pathways. The isolates displayed high metabolic flexibility. With the changes in electron donors, the isolates metabolically toggled between relatively anoxic reductive iron/sulfur cycles and the oxidative cycles of manganese/ammonium and vice-versa. This property makes these microbes successful survivors in the highly dynamic Sino-Pacific sediments.
2017, 36(2): 78-87.
doi: 10.1007/s13131-016-0956-0
Abstract:
The key functional genes involved in temperature adaption of the Antarctic psychrotrophic bacterium Psychrobacter sp. G. were identified by transcriptomic sequencing. We analyzed the global transcriptional profile of Psychrobacter sp. G under cold stress (0℃) and heat stress (30℃), with the optimal growth temperature 20℃ as the control. There were large alterations of the transcriptome profile, including significant upregulation of 11 and 12 transcripts as well as significant downregulation of 47 and 42 transcripts in the cold and heat stress groups, respectively, compared to the control. The expression of various genes encoding enzymes and transcriptional regulators, including PfpI and TetR family transcriptional regulators under heat stress, as well as the expression of DEAD/DEAH box helicase and the IclR family of transcriptional regulators under cold stress, were upregulated significantly. The expression of several genes, most affiliated with TonB-dependent receptor and siderophore receptor, was downregulated significantly under both heat and cold stress. Many of the genes associated with the metabolism of fatty acid and ABC transporters were regulated differentially under different temperature stress. The results of this survey of transcriptome and temperature stress-relevant genes contribute to our understanding of the stress-resistant mechanism in Antarctic bacteria.
The key functional genes involved in temperature adaption of the Antarctic psychrotrophic bacterium Psychrobacter sp. G. were identified by transcriptomic sequencing. We analyzed the global transcriptional profile of Psychrobacter sp. G under cold stress (0℃) and heat stress (30℃), with the optimal growth temperature 20℃ as the control. There were large alterations of the transcriptome profile, including significant upregulation of 11 and 12 transcripts as well as significant downregulation of 47 and 42 transcripts in the cold and heat stress groups, respectively, compared to the control. The expression of various genes encoding enzymes and transcriptional regulators, including PfpI and TetR family transcriptional regulators under heat stress, as well as the expression of DEAD/DEAH box helicase and the IclR family of transcriptional regulators under cold stress, were upregulated significantly. The expression of several genes, most affiliated with TonB-dependent receptor and siderophore receptor, was downregulated significantly under both heat and cold stress. Many of the genes associated with the metabolism of fatty acid and ABC transporters were regulated differentially under different temperature stress. The results of this survey of transcriptome and temperature stress-relevant genes contribute to our understanding of the stress-resistant mechanism in Antarctic bacteria.
2017, 36(2): 88-93.
doi: 10.1007/s13131-017-0979-1
Abstract:
Genus Pseudoalteromonas belongs to Family Pseudoalteromonadaceae in Gammaproteobacteria. A cold-adapted gram-negative bacterium, hydrocarbon-degrading Pseudoalteromonas sp. NJ289, was isolated from sea-ice of the Antarctica region, and sequenced the whole genome through the next generation sequencing platform. The assembly yielded three contigs representing two chromosomes and one plasmid with the sizes of 3.2 Mb, 636 kb and 1.8 kb, respectively. The G+C contents of genome were 40.83% and included 3 589 ORFs. Functional annotation indicated some potential roles in enzymatic activity and environmental adaptability. This study may help for understanding the population diverse, evolutionary ecology and the microbial interaction.
Genus Pseudoalteromonas belongs to Family Pseudoalteromonadaceae in Gammaproteobacteria. A cold-adapted gram-negative bacterium, hydrocarbon-degrading Pseudoalteromonas sp. NJ289, was isolated from sea-ice of the Antarctica region, and sequenced the whole genome through the next generation sequencing platform. The assembly yielded three contigs representing two chromosomes and one plasmid with the sizes of 3.2 Mb, 636 kb and 1.8 kb, respectively. The G+C contents of genome were 40.83% and included 3 589 ORFs. Functional annotation indicated some potential roles in enzymatic activity and environmental adaptability. This study may help for understanding the population diverse, evolutionary ecology and the microbial interaction.
2017, 36(2): 94-104.
doi: 10.1007/s13131-017-0980-8
Abstract:
Marine magnetotactic bacteria were collected from the intertidal sediments of Yuehu Lake (China), where their abundance reached 103-104 ind./cm3. Diverse morphotypes of magnetotactic bacteria were observed, including cocci and oval, vibrio-, spirillum-, rod-, elliptical-, handle- and bar-shaped forms. The magnetococci were the most abundant, and had flagella arranged in parallel within a bundle. The majority of magnetosomes were arranged in one, two or multiple chains, although irregular arrangements were also evident. All the results of high-resolution transmission electron microscopy (HRTEM) analysis show that magnetosome crystals were composed of Fe3O4, and their morphology was specific to particular cell morphotypes. By the 16S rRNA gene sequence analysis, we found fourteen operational taxonomic units (OTUs) which were related to magnetotactic bacteria. Among these, thirteen belonged to the Alphaproteobacteria and one to the Gammaproteobacteria. Compared with known axenic and uncultured marine magnetotactic bacteria, the 16S rRNA gene sequences of most magnetotactic bacteria collected from the Yuehu Lake exhibited sequence identities ranging from 90.1% to 96.2% (<97%). The results indicate that microbial communities containing previously unidentified magnetotactic bacteria occur in the Yuehu Lake.
Marine magnetotactic bacteria were collected from the intertidal sediments of Yuehu Lake (China), where their abundance reached 103-104 ind./cm3. Diverse morphotypes of magnetotactic bacteria were observed, including cocci and oval, vibrio-, spirillum-, rod-, elliptical-, handle- and bar-shaped forms. The magnetococci were the most abundant, and had flagella arranged in parallel within a bundle. The majority of magnetosomes were arranged in one, two or multiple chains, although irregular arrangements were also evident. All the results of high-resolution transmission electron microscopy (HRTEM) analysis show that magnetosome crystals were composed of Fe3O4, and their morphology was specific to particular cell morphotypes. By the 16S rRNA gene sequence analysis, we found fourteen operational taxonomic units (OTUs) which were related to magnetotactic bacteria. Among these, thirteen belonged to the Alphaproteobacteria and one to the Gammaproteobacteria. Compared with known axenic and uncultured marine magnetotactic bacteria, the 16S rRNA gene sequences of most magnetotactic bacteria collected from the Yuehu Lake exhibited sequence identities ranging from 90.1% to 96.2% (<97%). The results indicate that microbial communities containing previously unidentified magnetotactic bacteria occur in the Yuehu Lake.
2017, 36(2): 105-110.
doi: 10.1007/s13131-017-0984-4
Abstract:
Nitrogen removal from media by microalgae provides the potential benefit of producing lipids for biodiesel and biomass. However, research is limited on algal growth and biomass under different nitrogen sources and provides little insight in terms of biofuel production. We studied the influences of nitrogen sources on cell growth and lipid accumulation of Chlamydomonas sp. ICE-L, one of a promising oil rich micro algal species. Chlamydomonas sp. ICE-L grown in NH4Cl medium had maximum growth rate. While the highest dry biomass of 0.28 g/L was obtained in media containing NH4NO3, the highest lipid content of 0.21 g/g was achieved under nitrogen-deficiency condition with a dry biomass of 0.24 g/L. In terms of total polyunsaturated fatty acids (PUFAs) production, NH4NO3 and NH4Cl media performed better than nitrogen-deficiency and KNO3 media. Furthermore, NH4NO3 and NH4Cl media elucidated better results on C18:3 and C20:5 productions while KNO3 and -N conditions were better in C16:0, C18:1 and C18:2, comparatively.
Nitrogen removal from media by microalgae provides the potential benefit of producing lipids for biodiesel and biomass. However, research is limited on algal growth and biomass under different nitrogen sources and provides little insight in terms of biofuel production. We studied the influences of nitrogen sources on cell growth and lipid accumulation of Chlamydomonas sp. ICE-L, one of a promising oil rich micro algal species. Chlamydomonas sp. ICE-L grown in NH4Cl medium had maximum growth rate. While the highest dry biomass of 0.28 g/L was obtained in media containing NH4NO3, the highest lipid content of 0.21 g/g was achieved under nitrogen-deficiency condition with a dry biomass of 0.24 g/L. In terms of total polyunsaturated fatty acids (PUFAs) production, NH4NO3 and NH4Cl media performed better than nitrogen-deficiency and KNO3 media. Furthermore, NH4NO3 and NH4Cl media elucidated better results on C18:3 and C20:5 productions while KNO3 and -N conditions were better in C16:0, C18:1 and C18:2, comparatively.
2017, 36(2): 111-121.
doi: 10.1007/s13131-017-0969-3
Abstract:
The water quality grades of phosphate (PO4-P) and dissolved inorganic nitrogen (DIN) are integrated by spatial partitioning to fit the global and local semi-variograms of these nutrients. Leave-one-out cross validation is used to determine the statistical inference method. To minimize absolute average errors and error mean squares, stratified Kriging (SK) interpolation is applied to DIN and ordinary Kriging (OK) interpolation is applied to PO4-P. Ten percent of the sites is adjusted by considering their impact on the change in deviations in DIN and PO4-P interpolation and the resultant effect on areas with different water quality grades. Thus, seven redundant historical sites are removed. Seven historical sites are distributed in areas with water quality poorer than Grade IV at the north and south branches of the Changjiang (Yangtze River) Estuary and at the coastal region north of the Hangzhou Bay. Numerous sites are installed in these regions. The contents of various elements in the waters are not remarkably changed, and the waters are mixed well. Seven sites that have been optimized and removed are set to water with quality Grades III and IV. Optimization and adjustment of unrestricted areas show that the optimized and adjusted sites are mainly distributed in regions where the water quality grade undergoes transition. Therefore, key sites for adjustment and optimization are located at the boundaries of areas with different water quality grades and seawater.
The water quality grades of phosphate (PO4-P) and dissolved inorganic nitrogen (DIN) are integrated by spatial partitioning to fit the global and local semi-variograms of these nutrients. Leave-one-out cross validation is used to determine the statistical inference method. To minimize absolute average errors and error mean squares, stratified Kriging (SK) interpolation is applied to DIN and ordinary Kriging (OK) interpolation is applied to PO4-P. Ten percent of the sites is adjusted by considering their impact on the change in deviations in DIN and PO4-P interpolation and the resultant effect on areas with different water quality grades. Thus, seven redundant historical sites are removed. Seven historical sites are distributed in areas with water quality poorer than Grade IV at the north and south branches of the Changjiang (Yangtze River) Estuary and at the coastal region north of the Hangzhou Bay. Numerous sites are installed in these regions. The contents of various elements in the waters are not remarkably changed, and the waters are mixed well. Seven sites that have been optimized and removed are set to water with quality Grades III and IV. Optimization and adjustment of unrestricted areas show that the optimized and adjusted sites are mainly distributed in regions where the water quality grade undergoes transition. Therefore, key sites for adjustment and optimization are located at the boundaries of areas with different water quality grades and seawater.
