2023 Vol. 45, No. 1
Display Method:
2023, 45(1): 1-12.
doi: 10.12284/hyxb2023030
Abstract:
As potential mineral resources, rare earth elements and yttrium (REY)-rich sediments in deep-sea, have attracted a lot of attention in recent years. It is generally believed that the main source of REY should come from overlying seawater, but studies are in general lacking on the REY in overlying seawater in REY-enriched areas. In this paper, the dissolved concentrations and vertical distributions of 15 REY were studied in three stations located in the South Pacific Ocean, where enriched REY concentrations were found in sediments. Data obtained from this study were compared with data reported in adjacent waters and other ocean basins. The REY concentration in surface water of the study area was mainly controlled by wind-driven dust input, while the middle and deep waters were controlled by water masses. After the normalization of Post Achaean Australian Shale (PAAS) and North Pacific deep water (NPDW), the fractionation characteristics of REY can be clearly identified, and different water mass characteristics can be distinguished. When compared to data reported in other ocean basins and adjacent waters, more differences are found in surface waters due to dust and terrestrial inputs, while the REY concentrations in Indian Ocean are similar to the study region; the REY concentrations in deep water show a positive correlation with the age of water mass, i.e. the concentrations of REY from small to large are Atlantic, Indian Ocean, South Pacific, North Pacific.
As potential mineral resources, rare earth elements and yttrium (REY)-rich sediments in deep-sea, have attracted a lot of attention in recent years. It is generally believed that the main source of REY should come from overlying seawater, but studies are in general lacking on the REY in overlying seawater in REY-enriched areas. In this paper, the dissolved concentrations and vertical distributions of 15 REY were studied in three stations located in the South Pacific Ocean, where enriched REY concentrations were found in sediments. Data obtained from this study were compared with data reported in adjacent waters and other ocean basins. The REY concentration in surface water of the study area was mainly controlled by wind-driven dust input, while the middle and deep waters were controlled by water masses. After the normalization of Post Achaean Australian Shale (PAAS) and North Pacific deep water (NPDW), the fractionation characteristics of REY can be clearly identified, and different water mass characteristics can be distinguished. When compared to data reported in other ocean basins and adjacent waters, more differences are found in surface waters due to dust and terrestrial inputs, while the REY concentrations in Indian Ocean are similar to the study region; the REY concentrations in deep water show a positive correlation with the age of water mass, i.e. the concentrations of REY from small to large are Atlantic, Indian Ocean, South Pacific, North Pacific.
2023, 45(1): 13-24.
doi: 10.12284/hyxb2023008
Abstract:
In order to identify the functional diversity of the adjacent waters of the Changshan Islands in the ecotone between the Yellow Sea and the Bohai Sea, based on the quarterly survey of fish biological resources and environment factors from October 2016 to August 2017, combined with 13 functional traits such as feeding habit, trophic level, migration type, thermophily, resilience and fish eggs type, the spatio-temporal pattern of functional diversity and its relationship with environmental factors were studied by using community weighted mean index (CWM), functional diversity index and Spearman rank correlation analysis. The results showed that the dominant species of fish community in spring and winter were depressiform, warm temperate and demersal species with the characteristics of anterior or upper mouth, low growth coefficient, high vulnerability, low resilience and non-migration or short distance migration. The dominant species in summer and autumn showed more functional traits, such as long distance migration, pelagic, fusiform and compressiform. FRic in summer and autumn was significantly higher than that in spring and winter, FEve was the highest in spring, and FDiv was the lowest in autumn and was significantly lower than other seasons. FEve in spring and season and FDiv in spring and autumn showed a trend of high in the west and low in the east, while FRic in summer and winter and FEve in autumn showed a trend of high in the east and low in the west. There was a certain correlation between environmental factors and functional diversity index. As an ecotone between the Yellow Sea and the Bohai Sea, the functional traits of the dominant species and functional diversity show seasonal variations made by the fish migration, and the spatial pattern of functional diversity shows complexity and heterogeneity made by environment changing in the adjacent waters of the Changshan Islands.
In order to identify the functional diversity of the adjacent waters of the Changshan Islands in the ecotone between the Yellow Sea and the Bohai Sea, based on the quarterly survey of fish biological resources and environment factors from October 2016 to August 2017, combined with 13 functional traits such as feeding habit, trophic level, migration type, thermophily, resilience and fish eggs type, the spatio-temporal pattern of functional diversity and its relationship with environmental factors were studied by using community weighted mean index (CWM), functional diversity index and Spearman rank correlation analysis. The results showed that the dominant species of fish community in spring and winter were depressiform, warm temperate and demersal species with the characteristics of anterior or upper mouth, low growth coefficient, high vulnerability, low resilience and non-migration or short distance migration. The dominant species in summer and autumn showed more functional traits, such as long distance migration, pelagic, fusiform and compressiform. FRic in summer and autumn was significantly higher than that in spring and winter, FEve was the highest in spring, and FDiv was the lowest in autumn and was significantly lower than other seasons. FEve in spring and season and FDiv in spring and autumn showed a trend of high in the west and low in the east, while FRic in summer and winter and FEve in autumn showed a trend of high in the east and low in the west. There was a certain correlation between environmental factors and functional diversity index. As an ecotone between the Yellow Sea and the Bohai Sea, the functional traits of the dominant species and functional diversity show seasonal variations made by the fish migration, and the spatial pattern of functional diversity shows complexity and heterogeneity made by environment changing in the adjacent waters of the Changshan Islands.
2023, 45(1): 25-37.
doi: 10.12284/hyxb2023056
Abstract:
In order to understand the characteristics of food web structure in Zhongjieshan Islands, consumer samples of fish, shrimp and crabs, cephalopods, shellfish and zooplankton were collected from Zhongjieshan Islands in July 2020. Based on the carbon and nitrogen stable isotope techniques, the contributions of the four potential carbon sources (macroalgae, phytoplankton, suspended particulate organic matter (POM) and substrate organic matter (SOM)) to consumers, as well as the food web structure and nutritional relationship of the Zhongjieshan Islands were analyzed. The results revealed that the δ13C values of carbon sources ranged from −22.93‰ to −9.73‰, and the δ15N values ranged from 1.72‰ to 7.68‰. The δ13C values of consumers ranged from −21.95‰ to −12.55‰, and the δ15N values of consumers ranged from 4.13‰ to 12.92‰. One-way analysis of variance showed that there were significant differences in carbon and nitrogen stable isotopes among different carbon sources and different groups of consumers (p<0.01). SIBER model was used to analyze the trophic structure indexes of the regional ecosystem of Zhongjieshan Islands. Compared with the research results of other sea areas, it was found that the level of food source diversity (CR), trophic level length (NR) and total niche area (TA) were relatively high. SIAR model was used to calculate the carbon source contribution rate. The results showed that phytoplankton and POM were important carbon sources, with an average contribution rate of 29.63% and 28.72%. The maximum contribution rate of phytoplankton to zooplankton was 80.58%, and the maximum contribution rate of POM to fish was 79.74%; the maximum contribution rate of SOM to shrimp and crab was 49.94%; the carbon source contribution of macroalgae to consumers was the lowest, with an average of 18.37%. The mean trophic level range of the main consumers in Zhongjieshan Islands was 1.58 to 3.63, and the trophic level was 3. The average trophic level from big to small was as follows of cephalopods (3.09), fish (3.00), shrimps and crabs (2.70), shellfish (1.82). The consumers in the waters of Zhongjieshan Islands were mainly low and intermediate carnivores, and there were few omnivores and high carnivores. This study initially constructed the ecosystem food web of Zhongjieshan Islands, which provided reference data for understanding the trophic structure in this area, and also provided theoretical information for further study of the ecosystem.
In order to understand the characteristics of food web structure in Zhongjieshan Islands, consumer samples of fish, shrimp and crabs, cephalopods, shellfish and zooplankton were collected from Zhongjieshan Islands in July 2020. Based on the carbon and nitrogen stable isotope techniques, the contributions of the four potential carbon sources (macroalgae, phytoplankton, suspended particulate organic matter (POM) and substrate organic matter (SOM)) to consumers, as well as the food web structure and nutritional relationship of the Zhongjieshan Islands were analyzed. The results revealed that the δ13C values of carbon sources ranged from −22.93‰ to −9.73‰, and the δ15N values ranged from 1.72‰ to 7.68‰. The δ13C values of consumers ranged from −21.95‰ to −12.55‰, and the δ15N values of consumers ranged from 4.13‰ to 12.92‰. One-way analysis of variance showed that there were significant differences in carbon and nitrogen stable isotopes among different carbon sources and different groups of consumers (p<0.01). SIBER model was used to analyze the trophic structure indexes of the regional ecosystem of Zhongjieshan Islands. Compared with the research results of other sea areas, it was found that the level of food source diversity (CR), trophic level length (NR) and total niche area (TA) were relatively high. SIAR model was used to calculate the carbon source contribution rate. The results showed that phytoplankton and POM were important carbon sources, with an average contribution rate of 29.63% and 28.72%. The maximum contribution rate of phytoplankton to zooplankton was 80.58%, and the maximum contribution rate of POM to fish was 79.74%; the maximum contribution rate of SOM to shrimp and crab was 49.94%; the carbon source contribution of macroalgae to consumers was the lowest, with an average of 18.37%. The mean trophic level range of the main consumers in Zhongjieshan Islands was 1.58 to 3.63, and the trophic level was 3. The average trophic level from big to small was as follows of cephalopods (3.09), fish (3.00), shrimps and crabs (2.70), shellfish (1.82). The consumers in the waters of Zhongjieshan Islands were mainly low and intermediate carnivores, and there were few omnivores and high carnivores. This study initially constructed the ecosystem food web of Zhongjieshan Islands, which provided reference data for understanding the trophic structure in this area, and also provided theoretical information for further study of the ecosystem.
2023, 45(1): 38-52.
doi: 10.12284/hyxb2023020
Abstract:
To study the spatial distribution patterns of meiofauna in the southern Yellow Sea and the influencing environmental factors, two cruises were conducted in the southern Yellow Sea in August (summer) and November (autumn) 2020 to analyze the taxa composition, abundance, biomass, vertical distribution, community structure of meiofauna and their relationship with environmental factors. The results showed that a total of 15 taxa of meiofauna were identified, among which free-living marine nematode was the most dominant group, accounting for 75.6% and 84.6% of the total abundance of meiofauna in the two cruises, respectively. Other important groups were benthic copepods, rotifers and cladocerans. The average abundance of meiofauna in summer and autumn was (514.9±32.1) ind./(10 cm2) and (350.8±30.7) ind./(10 cm2), and the average biomass (dry weight) was (651.7±98.0) μg/(10 cm2) and (589.2±37.1) μg/(10 cm2), respectively. There were differences both in the spatial and temporal distribution of meiofauna. In terms of seasonal distribution, highly significant differences were found in the abundance and taxa composition of meiofauna. Combined with the analysis results of environmental factors, the sediment median diameter was the main environmental factor causing the differences. In terms of spatial distribution, the abundance of meiofauna and community structure differed significantly along the water depth gradient in summer, while no significant differences were found along the water depth gradient in autumn. The Yellow Sea Cold Water Mass was supposed to be the main factor affecting the spatial distribution of meiofauna in summer. The abundance and taxa diversity of meiofauna in this study were lower compared with other studies on meiofauna in the southern Yellow Sea. The sediment chlorophyll a and organic matter contents were the important factors causing the change in abundance of meiofauna in the southern Yellow Sea. The assessment of the abundance ratio of marine nematodes to copepods (N/C ratio) showed the presence of organic pollution in the area in autumn, while this result was not consistent with that of the macrofaunal assemblages in the environmental quality evaluation of the same area, and further studies are needed for the application of N/C ratio to evaluate the environmental quality.
To study the spatial distribution patterns of meiofauna in the southern Yellow Sea and the influencing environmental factors, two cruises were conducted in the southern Yellow Sea in August (summer) and November (autumn) 2020 to analyze the taxa composition, abundance, biomass, vertical distribution, community structure of meiofauna and their relationship with environmental factors. The results showed that a total of 15 taxa of meiofauna were identified, among which free-living marine nematode was the most dominant group, accounting for 75.6% and 84.6% of the total abundance of meiofauna in the two cruises, respectively. Other important groups were benthic copepods, rotifers and cladocerans. The average abundance of meiofauna in summer and autumn was (514.9±32.1) ind./(10 cm2) and (350.8±30.7) ind./(10 cm2), and the average biomass (dry weight) was (651.7±98.0) μg/(10 cm2) and (589.2±37.1) μg/(10 cm2), respectively. There were differences both in the spatial and temporal distribution of meiofauna. In terms of seasonal distribution, highly significant differences were found in the abundance and taxa composition of meiofauna. Combined with the analysis results of environmental factors, the sediment median diameter was the main environmental factor causing the differences. In terms of spatial distribution, the abundance of meiofauna and community structure differed significantly along the water depth gradient in summer, while no significant differences were found along the water depth gradient in autumn. The Yellow Sea Cold Water Mass was supposed to be the main factor affecting the spatial distribution of meiofauna in summer. The abundance and taxa diversity of meiofauna in this study were lower compared with other studies on meiofauna in the southern Yellow Sea. The sediment chlorophyll a and organic matter contents were the important factors causing the change in abundance of meiofauna in the southern Yellow Sea. The assessment of the abundance ratio of marine nematodes to copepods (N/C ratio) showed the presence of organic pollution in the area in autumn, while this result was not consistent with that of the macrofaunal assemblages in the environmental quality evaluation of the same area, and further studies are needed for the application of N/C ratio to evaluate the environmental quality.
2023, 45(1): 53-61.
doi: 10.12284/hyxb2023028
Abstract:
According to the Pholis fangi otoliths collected from bottom-trawl surveys in Haizhou Bay during from 2015 to 2019, linear mixed-effects model (LMEM) was used to study the interannual variation of growth rate of P. fangi from 2013 to 2018 and assess the response of the growth of P. fangi at different ages to external environmental factors such as bottom temperature, chlorophyll content and population density. The results showed that the otolith increment of P. fangi differed significantly between ages, with the mean otolith increment of 0.327 mm at 0 year old, significantly higher than that at another ages. The random-effects showed that the growth rate of P. fangi showed an increasing trend from 2013 to 2015, with a fluctuating trend from 2016 to 2018. The main factors affecting the growth of P. fangi at 0 year old were bottom temperature and population density. The growth rate increased and then decreased with the increase of bottom temperature, and decreased with the increase of population density. The effect of environmental factors on the growth rate of P. fangi at 1 year old were not significant, reflecting the ability of adults to adapt to the environment. This study provided insight into the growth dynamics of fish in response to biotic and abiotic factors, which will help to cope with the impact of climate change on fishery ecosystems.
According to the Pholis fangi otoliths collected from bottom-trawl surveys in Haizhou Bay during from 2015 to 2019, linear mixed-effects model (LMEM) was used to study the interannual variation of growth rate of P. fangi from 2013 to 2018 and assess the response of the growth of P. fangi at different ages to external environmental factors such as bottom temperature, chlorophyll content and population density. The results showed that the otolith increment of P. fangi differed significantly between ages, with the mean otolith increment of 0.327 mm at 0 year old, significantly higher than that at another ages. The random-effects showed that the growth rate of P. fangi showed an increasing trend from 2013 to 2015, with a fluctuating trend from 2016 to 2018. The main factors affecting the growth of P. fangi at 0 year old were bottom temperature and population density. The growth rate increased and then decreased with the increase of bottom temperature, and decreased with the increase of population density. The effect of environmental factors on the growth rate of P. fangi at 1 year old were not significant, reflecting the ability of adults to adapt to the environment. This study provided insight into the growth dynamics of fish in response to biotic and abiotic factors, which will help to cope with the impact of climate change on fishery ecosystems.
2023, 45(1): 62-70.
doi: 10.12284/hyxb2023004
Abstract:
As a typical dwelled tidal shellfish, Sinonovacula constricta is often exposed to sulfide-rich environment and shows strong sulfide tolerance. The cytosolic sulfotransferase 1B1 (SULT1B1) is located at downstream of the sulfur metabolism pathway, while it is a key enzyme catalyzing the sulfation reaction and plays an important role in the biotransformation of endogenous substances such as thyroid hormones (THs). In order to study the role of ScSULT1B1-12 in sulfur resistance, the sequence characteristics were analyzed by bioinformatics method. Combined with the changes of blood\begin{document}${\rm {SO}} _4^{2-} $\end{document} ![]()
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As a typical dwelled tidal shellfish, Sinonovacula constricta is often exposed to sulfide-rich environment and shows strong sulfide tolerance. The cytosolic sulfotransferase 1B1 (SULT1B1) is located at downstream of the sulfur metabolism pathway, while it is a key enzyme catalyzing the sulfation reaction and plays an important role in the biotransformation of endogenous substances such as thyroid hormones (THs). In order to study the role of ScSULT1B1-12 in sulfur resistance, the sequence characteristics were analyzed by bioinformatics method. Combined with the changes of blood
2023, 45(1): 71-79.
doi: 10.12284/hyxb2023022
Abstract:
Coral bleaching has become increasingly severe in recent years. Bleaching means a decrease in the symbiotic zooxanthellae density in corals. However, the significance of lipids in corals to maintain the stability of energy supply when the zooxanthellae density decreases remains unclear. Favia palauensis and Porites lutea samples collected in the Xisha Islands in March and June 2020 as materials were used in this study. By combining physiological parameters (zooxanthellae density and lipid content) with geochemical indexes (stable nitrogen isotope δ15Nz value of zooxanthellae), the response of coral lipids to the changes in zooxanthellae density and photosynthetic intensity was investigated. The results showed that the zooxanthellae density and δ15Nz value of two genera of corals decreased significantly in summer, implying that the decrease in zooxanthellae density in summer resulted in a decrease in their photosynthetic intensity. At the same time, the lipid content of the two genera of corals also decreased significantly, and the lipid content was positively correlated with zooxanthellae density and δ15Nz value, indicating that there was a coupling relationship between the coral lipid content and the changes of the photosynthetic intensity of zooxanthellae. When photosynthesis intensity decreases, coral can better maintain the stability of energy supply by consuming their own stored lipids, which is of great significance to improve their adaptability to environmental stress and bleaching resilience.
Coral bleaching has become increasingly severe in recent years. Bleaching means a decrease in the symbiotic zooxanthellae density in corals. However, the significance of lipids in corals to maintain the stability of energy supply when the zooxanthellae density decreases remains unclear. Favia palauensis and Porites lutea samples collected in the Xisha Islands in March and June 2020 as materials were used in this study. By combining physiological parameters (zooxanthellae density and lipid content) with geochemical indexes (stable nitrogen isotope δ15Nz value of zooxanthellae), the response of coral lipids to the changes in zooxanthellae density and photosynthetic intensity was investigated. The results showed that the zooxanthellae density and δ15Nz value of two genera of corals decreased significantly in summer, implying that the decrease in zooxanthellae density in summer resulted in a decrease in their photosynthetic intensity. At the same time, the lipid content of the two genera of corals also decreased significantly, and the lipid content was positively correlated with zooxanthellae density and δ15Nz value, indicating that there was a coupling relationship between the coral lipid content and the changes of the photosynthetic intensity of zooxanthellae. When photosynthesis intensity decreases, coral can better maintain the stability of energy supply by consuming their own stored lipids, which is of great significance to improve their adaptability to environmental stress and bleaching resilience.
2023, 45(1): 80-88.
doi: 10.12284/hyxb2023010
Abstract:
The microorganisms that generate and utilize methane are recognized as the key parts of global methane cycle, and their metabolic process has significant effects on global climate change. The knowledge upon composition and distribution characteristics of these methane metabolic microorganisms in global ocean sediments is the basis to understand the participation of methane metabolizing microorganisms in marine sediments in methane cycle. Pyrosequencing based on functional gene mcrA (methyl coenzyme-M reductase A) was applied to study the community composition and abundance of methane metabolic microbes in global ocean sediments, and their abundance together with those of archaea were estimated with fluorescence real-time quantitative PCR. Compared with other marine habitats, the methane metabolic archaeal communities in the deep ocean sediments had a much lower diversity and simpler community structure. The α-diversity in Atlantic Ocean and Indian Ocean was significantly higher than that in the Pacific Ocean (p<0.05). Methanogens revealed from this study belong to three orders, Methanobacteriales, Methanosarcinales, and Methanomicrobiales. Methanomicrobiales as the dominant one was predominated by an unknown OSD group. The average abundance (wet weight, the same below) of archaeal 16S rRNA gene in all sediments was 8.81×106 copies/g. Those in Atlantic Ocean was lower than the other two oceans; while those in the Mariana Trench was lower than in the northern part of the South China Sea, and tended to decrease with the increase of sediment depth. The abundance of mcrA gene in all sediment samples was 1.38×103–8.25×104 copies/g. Those in Atlantic Ocean was the highest. It revealed that low abundance and diversity of methane metabolic archaea in the deep-sea sediments, and the high similarities among different communities among samples in different oceans. In addition, the OSD group recovered as the predominant group in this study had no close relationship with any other known genotypes in the GenBank, therefore, its taxonomic status was unknown and deserve further study.
The microorganisms that generate and utilize methane are recognized as the key parts of global methane cycle, and their metabolic process has significant effects on global climate change. The knowledge upon composition and distribution characteristics of these methane metabolic microorganisms in global ocean sediments is the basis to understand the participation of methane metabolizing microorganisms in marine sediments in methane cycle. Pyrosequencing based on functional gene mcrA (methyl coenzyme-M reductase A) was applied to study the community composition and abundance of methane metabolic microbes in global ocean sediments, and their abundance together with those of archaea were estimated with fluorescence real-time quantitative PCR. Compared with other marine habitats, the methane metabolic archaeal communities in the deep ocean sediments had a much lower diversity and simpler community structure. The α-diversity in Atlantic Ocean and Indian Ocean was significantly higher than that in the Pacific Ocean (p<0.05). Methanogens revealed from this study belong to three orders, Methanobacteriales, Methanosarcinales, and Methanomicrobiales. Methanomicrobiales as the dominant one was predominated by an unknown OSD group. The average abundance (wet weight, the same below) of archaeal 16S rRNA gene in all sediments was 8.81×106 copies/g. Those in Atlantic Ocean was lower than the other two oceans; while those in the Mariana Trench was lower than in the northern part of the South China Sea, and tended to decrease with the increase of sediment depth. The abundance of mcrA gene in all sediment samples was 1.38×103–8.25×104 copies/g. Those in Atlantic Ocean was the highest. It revealed that low abundance and diversity of methane metabolic archaea in the deep-sea sediments, and the high similarities among different communities among samples in different oceans. In addition, the OSD group recovered as the predominant group in this study had no close relationship with any other known genotypes in the GenBank, therefore, its taxonomic status was unknown and deserve further study.
2023, 45(1): 89-101.
doi: 10.12284/hyxb2023018
Abstract:
Nitrification is a pivotal process in the marine nitrogen cycle. Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) drive the ammonia oxidation, which is the first and rate-limiting step in nitrification, and their relative contributions to nitrification are ones of the most important topics related to the nitrogen cycle in ocean. In this study, surface sediment samples at 20 sites from Bohai Sea and South Yellow Sea were collected in April and May, 2019. The relative contributions of AOA and AOB to nitrification potential were studied in the microcosmic experiment. The results showed that the potential nitrification rates (PNRs, in terms of nitrogen) ranged from 0.004 6 μmol/(g·d) to 0.283 1 μmol/(g·d), in which potential nitrification rate of AOA and AOB ranged from 0.004 3 μmol/(g·d) to 0.274 3 μmol/(g·d) and 0.000 4 μmol/(g·d) to 0.056 0 μmol/(g·d), respectively. AOA was the main contributor to the nitrification therein, whose contribution rate was 59.79%−97.95% in Bohai Sea and 18.47%−94.26% in South Yellow Sea, respectively. The potential nitrification rates in surface sediments from Bohai Sea were significantly higher than those from South Yellow Sea. Besides, salinity was a key environmental factor for potential nitrification rates, and high\begin{document}${{\rm {NO}}_3^-} $\end{document} ![]()
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Nitrification is a pivotal process in the marine nitrogen cycle. Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) drive the ammonia oxidation, which is the first and rate-limiting step in nitrification, and their relative contributions to nitrification are ones of the most important topics related to the nitrogen cycle in ocean. In this study, surface sediment samples at 20 sites from Bohai Sea and South Yellow Sea were collected in April and May, 2019. The relative contributions of AOA and AOB to nitrification potential were studied in the microcosmic experiment. The results showed that the potential nitrification rates (PNRs, in terms of nitrogen) ranged from 0.004 6 μmol/(g·d) to 0.283 1 μmol/(g·d), in which potential nitrification rate of AOA and AOB ranged from 0.004 3 μmol/(g·d) to 0.274 3 μmol/(g·d) and 0.000 4 μmol/(g·d) to 0.056 0 μmol/(g·d), respectively. AOA was the main contributor to the nitrification therein, whose contribution rate was 59.79%−97.95% in Bohai Sea and 18.47%−94.26% in South Yellow Sea, respectively. The potential nitrification rates in surface sediments from Bohai Sea were significantly higher than those from South Yellow Sea. Besides, salinity was a key environmental factor for potential nitrification rates, and high
2023, 45(1): 102-113.
doi: 10.12284/hyxb2023014
Abstract:
The Antarctic cruise routes across different regions of the global oceans, it is of great significance to understand the global distribution of ultraplankton. During 33rd Chinese Antarctic Expedition, we used flow cytometry to investigate large-scale latitudinal distribution of ultraplankton abundance and its effect factors in the surface water along the cruise routes. The results showed that picoplankton accounted for 60% of total chlorophyll a (Chl a) concentration in the tropic and temperate zones and the contribution of picoplankton to total Chl a concentration varied from 15% to 40% in the Southern Ocean. Prochlorococcus (Pro) were mainly distributed in the north of 40°S, Synechococcus (Syn) were distributed in the north of 50°S, while pico-eukaryotes (PEuk) and heterotrophic bacteria (HBac) were detected and distributed in the Southern Ocean and along the cruise routes. The average abundance of Pro, Syn, PEuk and HBac were (5.50±9.09)×103 cells/mL, (13.56±20.33)×103 cells/mL, (3.87± 3.08)×103
The Antarctic cruise routes across different regions of the global oceans, it is of great significance to understand the global distribution of ultraplankton. During 33rd Chinese Antarctic Expedition, we used flow cytometry to investigate large-scale latitudinal distribution of ultraplankton abundance and its effect factors in the surface water along the cruise routes. The results showed that picoplankton accounted for 60% of total chlorophyll a (Chl a) concentration in the tropic and temperate zones and the contribution of picoplankton to total Chl a concentration varied from 15% to 40% in the Southern Ocean. Prochlorococcus (Pro) were mainly distributed in the north of 40°S, Synechococcus (Syn) were distributed in the north of 50°S, while pico-eukaryotes (PEuk) and heterotrophic bacteria (HBac) were detected and distributed in the Southern Ocean and along the cruise routes. The average abundance of Pro, Syn, PEuk and HBac were (5.50±9.09)×103 cells/mL, (13.56±20.33)×103 cells/mL, (3.87± 3.08)×103
2023, 45(1): 114-124.
doi: 10.12284/hyxb2023016
Abstract:
Based on ecological observations of the northern Chukchi Sea and the western Canada Basin junction zore, We found that within the upper 150 m, the phytoplankton distribution was complicated by dominant water masses: the Melting Water (MW), the Alaskan Coastal Water (ACW) transported with the Beaufort Gyre (BG), and summer Bering Sea Water (sBSW). The changes of temperature and nutrients were closely related to water mass, and the physical-biochemical coupling effect further affects the distribution and community structure of phytoplankton. The Chl a maximum concentration layer often existed in the dim water of about 50 m depth. In the nutrient-rich sBSW and ACW dominant water-mass, phytoplankton were dominant by netplankton (74% of the total Chl a concentration) and picoplankton (65% of the total Chl a concentration). In the early stage of bloom, dissolved inorganic nitrogen (DIN) was relative limited to phosphate, while bioavailable nitrogen was still above the absolute limit threshold. The DIN-Salinity conservative mixing model showed that phytoplankton significantly removed nitrogen, and the nitrogen-uptake was positively related to Chl a concentration. The amount of nitrogen uptake in ACW water mass with slightly higher temperature was higher than that in sBSW water mass. In response to Arctic warming, the enhanced Beaufort Gyre, and nutrient supply from ACW and sBSW, Chl a concentration of phytoplankton in this region (ranged from 0.04−0.69 mg/m3 with an average of (0.327±0.163) mg/m3) were higher than the historical observations. This will increase the carbon absorption flux in the Arctic sea area, which is conducive to its development as a carbon sink area.
Based on ecological observations of the northern Chukchi Sea and the western Canada Basin junction zore, We found that within the upper 150 m, the phytoplankton distribution was complicated by dominant water masses: the Melting Water (MW), the Alaskan Coastal Water (ACW) transported with the Beaufort Gyre (BG), and summer Bering Sea Water (sBSW). The changes of temperature and nutrients were closely related to water mass, and the physical-biochemical coupling effect further affects the distribution and community structure of phytoplankton. The Chl a maximum concentration layer often existed in the dim water of about 50 m depth. In the nutrient-rich sBSW and ACW dominant water-mass, phytoplankton were dominant by netplankton (74% of the total Chl a concentration) and picoplankton (65% of the total Chl a concentration). In the early stage of bloom, dissolved inorganic nitrogen (DIN) was relative limited to phosphate, while bioavailable nitrogen was still above the absolute limit threshold. The DIN-Salinity conservative mixing model showed that phytoplankton significantly removed nitrogen, and the nitrogen-uptake was positively related to Chl a concentration. The amount of nitrogen uptake in ACW water mass with slightly higher temperature was higher than that in sBSW water mass. In response to Arctic warming, the enhanced Beaufort Gyre, and nutrient supply from ACW and sBSW, Chl a concentration of phytoplankton in this region (ranged from 0.04−0.69 mg/m3 with an average of (0.327±0.163) mg/m3) were higher than the historical observations. This will increase the carbon absorption flux in the Arctic sea area, which is conducive to its development as a carbon sink area.
2023, 45(1): 125-137.
doi: 10.12284/hyxb2023024
Abstract:
Shallow water bathymetry using remote sensing is an important technology in marine geodesy. The Stumpf ratio and Lyzenga polynomial methods, as classic representative algorithms, are widely used and many improved algorithms have been developed. However, these methods do not take into account the bathymetry ability of different spectra. In this study, we propose a bathymetry method based on spectral stratification. Firstly, according to the difference in the penetration ability of red, green and blue spectra to the waterbody, an image-based nonparametric spectral layering strategy is proposed to extract the red, green and blue layers. Then, based on the band bathymetric performance of different spectral layers, we constructed a bathymetric inversion optimization model by spectral layers and further obtained the shallow water bathymetry. The Changxian Reef in the Nansha sea area and Buck Island Reef in U.S. Virgin Islands are selected as test cases to validate the proposed method. Compared with the classical Stumpf ratio and Lyzenga polynomial methods, the root-mean-square error (RMSE), mean absolute error (MAE) and mean relative error (MRE) of the proposed method have decreased by 0.41−0.89 m, 0.35−0.65 m, and 4%−19% respectively. Particularly, the accuracy of the red light layer (i.e., the shallow water depth) is significantly improved, and the MRE is reduced by 58%−149%. Our findings suggest that the proposed bathymetry method based on spectral stratification is feasible and effective in improving the accuracy of the shallow water depth estimation and has good potential for future applications.
Shallow water bathymetry using remote sensing is an important technology in marine geodesy. The Stumpf ratio and Lyzenga polynomial methods, as classic representative algorithms, are widely used and many improved algorithms have been developed. However, these methods do not take into account the bathymetry ability of different spectra. In this study, we propose a bathymetry method based on spectral stratification. Firstly, according to the difference in the penetration ability of red, green and blue spectra to the waterbody, an image-based nonparametric spectral layering strategy is proposed to extract the red, green and blue layers. Then, based on the band bathymetric performance of different spectral layers, we constructed a bathymetric inversion optimization model by spectral layers and further obtained the shallow water bathymetry. The Changxian Reef in the Nansha sea area and Buck Island Reef in U.S. Virgin Islands are selected as test cases to validate the proposed method. Compared with the classical Stumpf ratio and Lyzenga polynomial methods, the root-mean-square error (RMSE), mean absolute error (MAE) and mean relative error (MRE) of the proposed method have decreased by 0.41−0.89 m, 0.35−0.65 m, and 4%−19% respectively. Particularly, the accuracy of the red light layer (i.e., the shallow water depth) is significantly improved, and the MRE is reduced by 58%−149%. Our findings suggest that the proposed bathymetry method based on spectral stratification is feasible and effective in improving the accuracy of the shallow water depth estimation and has good potential for future applications.
2023, 45(1): 138-146.
doi: 10.12284/hyxb2023006
Abstract:
In-situ monitoring of ammonia nitrogen (NH3-N) and nitrite (\begin{document}${\rm{NO}}_2^- $\end{document} ![]()
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In-situ monitoring of ammonia nitrogen (NH3-N) and nitrite (
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