Mariculture has rapidly grown worldwide, which might greatly influence the biogeochemical cycle of organic carbon in coastal seas. In this study, several geochemical parameters, including grain size composition, sedim...Mariculture has rapidly grown worldwide, which might greatly influence the biogeochemical cycle of organic carbon in coastal seas. In this study, several geochemical parameters, including grain size composition, sedimentary total organic carbon (TOC), total nitrogen (TN), stable carbon (δ13C) and nitrogen (δ15N) isotopic compositions, were analyzed for surface sediments collected from different mariculture zones of Sanggou Bay and in different seasons. We investigated the composition and distribution of or- ganic matter in surface sediments and further evaluated the contribution of mariculture activities to TOC sources. The TOC and TN contents (mass percentage) in the bay were in the range of 0.14% to 1.45% and 0.03% to 0.20%, respectively. The spatial distribution indicated that sedimentary TOC and TN contents in shellfish monoculture and shellfish-kelp polyculture zones were higher than in other mariculture zones, which might be related to grain size composition and mariculture organisms. Seasonal variations of TOC contents were observed in different mariculture zones. The TOC/TN atomic ratio (C/N),δ13C and δ15N were in the ranges of 5.97 to 10.97, 21.76‰ to 13.14‰ and 2.13‰ to 8.08‰, respectively, implying that sedimentary organic matter in Sanggou Bay was the mixture of marine phytoplankton, terrestrial and maricultural sources. A simple mixing model based on δ13C was applied and the results indicated that the relative contributions of organic carbon sources in Sanggou Bay followed the order kelp (36.6%) marine phytoplankton (28.7%) shellfish bio-deposition (23.8%) terrestrial input (10.9%). Surface sediments in Sanggou Bay were domi- nated by mariculture-derived organic carbon, which on average accounted for 60.4% of TOC.展开更多
The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay （SGB） and the adjacent Ailian Bay （ALB） and Lidao Bay （LDB） in Shandong Peninsula,eastern China.The species comp...The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay （SGB） and the adjacent Ailian Bay （ALB） and Lidao Bay （LDB） in Shandong Peninsula,eastern China.The species composition and cell abundance of phytoplankton in the bay waters in spring （April 2011）,summer （August 2011）,autumn （October 2011）,and winter （January 2012） were examined using the Uterm6hl method.A total of 80 taxa of phytoplankton that belong to 39 genera of 3 phyla were identified.These included 64 species of 30 genera in the Phylum Bacillariophyta,13 species of 8 genera in the Phylum Dinophyta,and 3 species of 1 genus in the Phylum Chrysophyta.During the four seasons,the number of phytoplankton species （43） was the highest in spring,followed by summer and autumn （40）,and the lowest number ofphytoplankton species （35） was found in winter.Diatoms,especially Paralia sulcata （Ehrenberg） Cleve and Coscinodiscus oculus-iridis Ehrenberg,were predominant in the phytoplankton community throughout the study period,whereas the dominance of dinoflagellate appeared in summer only.The maximum cell abundance of phytoplankton was detected in summer （average 8.08 × 103 cells L-1） whereas their minimum abundance was found in autumn （average 2.60 x 103 cellsL-1）.The phytoplankton abundance was generally higher in the outer bay than in the inner bay in spring and autumn.In summer,the phytoplankton cells were mainly concentrated in the south of inner SGB,with peak abundance observed along the western coast.In winter,the distribution of phytoplankton cells showed 3 patches,with peak abundance along the western coast as well.On seasonal average,the Shannon-Wiener diversity indices of phytoplankton community ranged from 1.17 to 1.78 （autumn 〉 summer 〉 spring 〉 winter）,and the Pielou＇s evenness indices of phytoplankton ranged from 0.45 to 0.65 （autumn 〉 spring 〉 summer〉 winter）.According to the results of canonical correspondence analysis,phosphate level w展开更多
Naturally existing stable carbon and nitrogen isotopes are important in the study of sedimentary organic matter sources. To identify the sources of sedimentary organic matter in Sanggou Bay and its adjacent areas, whi...Naturally existing stable carbon and nitrogen isotopes are important in the study of sedimentary organic matter sources. To identify the sources of sedimentary organic matter in Sanggou Bay and its adjacent areas, which is characterized by high-density shellfish and seaweed aquaculture, the grain size, organic carbon （OC）, total nitrogen （TN）, carbon and nitrogen isotopic composition （δ13C andδ15N） of organic matter in the surface sediment were determined. The results showed that, in August, sedimentary OC and TN ranged from 0.17% to 0.76% and 0.04% to 0.14%, respectively. In November, OC and TN ranged from 0.23% to 0.87% and 0.05% to 0.14%, respectively. There was a significant positive correlation between OC and TN （R=0.98, P＆lt;0.0001）, indicating that OC and TN were homologous. In August, theδ13C andδ15N of organic matter varied from -23.06‰ to -21.59‰ and 5.10‰ to 6.31‰, respectively. In November,δ13C andδ15N ranged from -22.87‰ to -21.34‰ and 5.13‰ to 7.31‰, respectively. This study found that the major sources of sedimentary organic matter were marine shellfish biodeposition, seaweed farming, and soil organic matter. Using a three-end-member mixed model, we estimated that the dominant source of sedimentary organic matter was shellfish biodeposition, with an average contribution rate of 65.53% in August and 43.00% in November. Thus, shellfish farming had a significant influence on the coastal carbon cycle.展开更多
In this study, we assessed the burial fluxes and source appointment of different forms of carbon in core sediments collected from culture areas in the Sanggou Bay, and preliminarily analyzed the reasons for the greate...In this study, we assessed the burial fluxes and source appointment of different forms of carbon in core sediments collected from culture areas in the Sanggou Bay, and preliminarily analyzed the reasons for the greater proportion of inorganic carbon burial fluxes （BFTIc）. The average content of total carbon （TC） in the Sanggou Bay was 2.14%. Total organic carbon （TOC） accounted for a small proportion in TC, more than 65% of which derived from terrigenous organic carbon （Ct）, and while the proportion of marine-derived organic carbon （Ca） increased significantly since the beginning of large-scale aquaculture. Total inorganic carbon （TIC） accounted for 60%-75% of TC, an average of which was 60%, with a maximum up to 90% during flourishing periods （1880-1948） of small natural shellfish derived from seashells inorganic carbon （SheU-IC）. The TC burial fluxes ranged from 31 g/（m2.a） to 895 g/（m2.a） with an average of 227 g/（m2.a）, which was dominated by TIC （about 70%）. Shell-IC was the main source of TIC and even TC. As the main food of natural shellfish, biogenic silica （BSi） negatively correlated with BFTIc through affecting shellfish breeding. BFTIc of Sta. S1, influenced greatly by the Yellow Sea Coastal Current, had a certain response to Pacific Decadal Oscillation （PDO） in some specific periods.展开更多
The phosphorus cycle is studied during 2013–2014 in the Sanggou Bay（SGB）, which is a typical aquaculture area in northern China. The forms of measured phosphorus include dissolved inorganic phosphorus（DIP）, disso...The phosphorus cycle is studied during 2013–2014 in the Sanggou Bay（SGB）, which is a typical aquaculture area in northern China. The forms of measured phosphorus include dissolved inorganic phosphorus（DIP）, dissolved organic phosphorus（DOP）, particulate inorganic phosphorus（PIP）, and particulate organic phosphorus（POP）.DIP and PIP are the major forms of total dissolved phosphorus（TDP） and total particulate phosphorus（TPP）,representing 51%–75% and 53%–80%, respectively. The concentrations and distributions of phosphorus forms vary among seasons relative to aquaculture cycles, fluvial input, and hydrodynamic conditions. In autumn the concentration of DIP is significantly higher than in other seasons（P〈0.01）, and higher concentrations are found in the west of the bay. In winter and spring the phosphorus concentrations are higher in the east of the bay than in the west. In summer, the distributions of phosphorus forms are uniform. A preliminary phosphorus budget is developed, and shows that SGB is a net sink of phosphorus. A total of 1.80×10^7 mol/a phosphorus is transported into the bay. The Yellow Sea is the major source of net input of phosphorus（61%）, followed by submarine groundwater discharge（SGD）（27%）, river input（11%）, and atmospheric deposition（1%）. The main phosphorus sink is the harvest of seaweeds（Saccharina japonica and Gracilaria lemaneiformis）, bivalves（Chlamys farreri）,and oysters（Crassostrea gigas）, accounting for a total of 1.12×10^7 mol/a. Burial of phosphorus in sediment is another important sink, accounting for 7.00×10^6 mol/a. Biodeposition by bivalves is the major source of phosphorus in sediment, accounting for 54% of the total.展开更多
Integrated multi-trophic aquaculture(IMTA)has been considered as an ecofriendly culture system providing a potential solution to environmental risks caused by intensive monoculture system.However,the impact of IMTA on...Integrated multi-trophic aquaculture(IMTA)has been considered as an ecofriendly culture system providing a potential solution to environmental risks caused by intensive monoculture system.However,the impact of IMTA on phytoplankton remains unclear.In this study,the spatial and temporal variations of phytoplankton in Sanggou Bay were investigated seasonally based on 21 sampling sites covering three cultivation zones(bivalve zone,IMTA zone,and kelp zone)and one control zone(without aquatic cultivation).In total,128 phytoplankton species,with diatoms and dinoflagellates as the dominant groups,were obtained across the whole year,and the mean Shannon diversity index(H')and species richness(SR)were determined as 1.39 and 9.39,respectively.The maximum chlorophyll a(Chl-a)(6.32μg L^(-1))and plankton diversity(H'of 1.97)occurred in summer and autumn,respectively.Compared to other zones,the bivalve zone displayed significantly higher Chl-a and lower H'in majority of time.Pairwise PERMANOVA analysis indicated that the phytoplankton assemblage in the bivalve zone was significantly different with the control and kelp zones,while the IMTA zone maintained close to other three zones.Based on generalized additive models,temperature,NO_(2)^(-)-N,N/P ratio,SiO_(3)^(2-)-Si,and salinity were determined as the key factors underlying Chl-a and phytoplankton diversity.Addi-tionally,the results of redundancy analysis further indicated that the phytoplankton assemblage in the bivalve zone is positively re-lated with nutrients such as NO_(3)^(-)-N and NH_(4)^(+)-N as well as water depth,while the phytoplankton assemblages in the kelp,control,and IMTA zones are associated with NO_(2)^(-)-N,SiO_(3)^(2-)-Si,and salinity.Taken all observations into consideration together,it can be inferred that IMTA can effectively reduce Chl-a level compared to bivalve monoculture by reducing the nutrients.However,the SR,H’,and species composition of phytoplankton are primarily determined by local environment factors such as temperature,water depth,salinit展开更多
The standing crop and primary production of benthic microalgae on tidal flats have seasonally been observed in the Sanggou and Jiaozhou Bays of the northern China coast during 1999 - 2000. The results show that the an...The standing crop and primary production of benthic microalgae on tidal flats have seasonally been observed in the Sanggou and Jiaozhou Bays of the northern China coast during 1999 - 2000. The results show that the annual primary productions of benthic microalgae on tidal flats in the two bays are 2 532 and 7 542 tons carbon, which would be able to support 3.1 x 103 and 9.2 x 103 tons shellfish meat, respectively. The nature of sediment is essential for governing the biomass and primary production of benthic microalgae on tidal flats. The biomass and primary production of benthic microalgae on tidal flats with muddy sediments are higher than those with sandy sediments, which resulted from higher nutrient concentration and lower grazing pressure. That is the reason why in comparison with Xiangshan Bay the standing crop and production of benthic microalgae on tidal flats of the Sanggou and Jiaozhou Bays are low. Light was a key factor controlling vertical distribution of biomass and production of benthic microalgae on tidal flats of the two bays, resulted in appearance of maximum chlorophyll a and primary production at the surface layer and sharply decreased with depth of sediment.展开更多
The sediment resuspension mechanisms in Sungo Bay, a large-scale aquaculture area in north China, were investigated by analysing data collected during several periods from 2005 to 2006. Nortek 6M ADV current meter and...The sediment resuspension mechanisms in Sungo Bay, a large-scale aquaculture area in north China, were investigated by analysing data collected during several periods from 2005 to 2006. Nortek 6M ADV current meter and YSI6600 were used to collect the field data on current speed, current direction and water turbidities 1 m above the bottom. Based on the collected field data, it could be found that wind-waves and currents were the main driving force for sediment resuspension. The correlation between suspended sediment concentration （SSC） and turbidity （NTU） is SSC = 15.908 x In （NTU） ＋ 7.0888 （n = 33, R2 = 0.7209）. Taking the key factor （angle 0） into account, the combination effect between wave and current were expressed. Results showed that the combined shear stress （row） of wave stress （re） and current stress （rw） could be calculated by row = rc ＋ 2√ rcrw sin θ ＋ rw sin^2 θ. The critical shear stress for sediment resuspension was about 0.059 N/m^2. The correlation between suspended sediment concentration and critical shear stress could be expressed by rcw = 238.06 SSC ＋ 25.215 （n = 25, R^2 = 0.7298）.展开更多
基金funded by Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA23050402)the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology (Qingdao) (No. 2018SDKJ0501-3)+2 种基金the National Natural Science Foundation of China (No. 41276172)the Special Fund of Basic Research for Central non-profit Scientific Research Institute (No. 2014A01 YY01)Special Fund of Basic Research for Chinese Academy of Fishery Sciences (Nos. 2016HY-JC01-01 and 2017GH09)
文摘Mariculture has rapidly grown worldwide, which might greatly influence the biogeochemical cycle of organic carbon in coastal seas. In this study, several geochemical parameters, including grain size composition, sedimentary total organic carbon (TOC), total nitrogen (TN), stable carbon (δ13C) and nitrogen (δ15N) isotopic compositions, were analyzed for surface sediments collected from different mariculture zones of Sanggou Bay and in different seasons. We investigated the composition and distribution of or- ganic matter in surface sediments and further evaluated the contribution of mariculture activities to TOC sources. The TOC and TN contents (mass percentage) in the bay were in the range of 0.14% to 1.45% and 0.03% to 0.20%, respectively. The spatial distribution indicated that sedimentary TOC and TN contents in shellfish monoculture and shellfish-kelp polyculture zones were higher than in other mariculture zones, which might be related to grain size composition and mariculture organisms. Seasonal variations of TOC contents were observed in different mariculture zones. The TOC/TN atomic ratio (C/N),δ13C and δ15N were in the ranges of 5.97 to 10.97, 21.76‰ to 13.14‰ and 2.13‰ to 8.08‰, respectively, implying that sedimentary organic matter in Sanggou Bay was the mixture of marine phytoplankton, terrestrial and maricultural sources. A simple mixing model based on δ13C was applied and the results indicated that the relative contributions of organic carbon sources in Sanggou Bay followed the order kelp (36.6%) marine phytoplankton (28.7%) shellfish bio-deposition (23.8%) terrestrial input (10.9%). Surface sediments in Sanggou Bay were domi- nated by mariculture-derived organic carbon, which on average accounted for 60.4% of TOC.
基金supported by the National Program on Key Basic Research Project of China (Grant Nos. 2011CB409804 and 2015CB954002)Program for New Century Excellent Talents in University (NCET-12-1065)the National Natural Science Foundation of China (Grant No.41176136) to J. Sun
文摘The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay （SGB） and the adjacent Ailian Bay （ALB） and Lidao Bay （LDB） in Shandong Peninsula,eastern China.The species composition and cell abundance of phytoplankton in the bay waters in spring （April 2011）,summer （August 2011）,autumn （October 2011）,and winter （January 2012） were examined using the Uterm6hl method.A total of 80 taxa of phytoplankton that belong to 39 genera of 3 phyla were identified.These included 64 species of 30 genera in the Phylum Bacillariophyta,13 species of 8 genera in the Phylum Dinophyta,and 3 species of 1 genus in the Phylum Chrysophyta.During the four seasons,the number of phytoplankton species （43） was the highest in spring,followed by summer and autumn （40）,and the lowest number ofphytoplankton species （35） was found in winter.Diatoms,especially Paralia sulcata （Ehrenberg） Cleve and Coscinodiscus oculus-iridis Ehrenberg,were predominant in the phytoplankton community throughout the study period,whereas the dominance of dinoflagellate appeared in summer only.The maximum cell abundance of phytoplankton was detected in summer （average 8.08 × 103 cells L-1） whereas their minimum abundance was found in autumn （average 2.60 x 103 cellsL-1）.The phytoplankton abundance was generally higher in the outer bay than in the inner bay in spring and autumn.In summer,the phytoplankton cells were mainly concentrated in the south of inner SGB,with peak abundance observed along the western coast.In winter,the distribution of phytoplankton cells showed 3 patches,with peak abundance along the western coast as well.On seasonal average,the Shannon-Wiener diversity indices of phytoplankton community ranged from 1.17 to 1.78 （autumn 〉 summer 〉 spring 〉 winter）,and the Pielou＇s evenness indices of phytoplankton ranged from 0.45 to 0.65 （autumn 〉 spring 〉 summer〉 winter）.According to the results of canonical correspondence analysis,phosphate level w
基金The Joint Fund Project of National Fund Committee and Shandong Province under contract No.U1406403the State Oceanic Administration Project of China under contract Nos DOMEP(MEA)-01-01 and DOMEP(MEA)-02
文摘Naturally existing stable carbon and nitrogen isotopes are important in the study of sedimentary organic matter sources. To identify the sources of sedimentary organic matter in Sanggou Bay and its adjacent areas, which is characterized by high-density shellfish and seaweed aquaculture, the grain size, organic carbon （OC）, total nitrogen （TN）, carbon and nitrogen isotopic composition （δ13C andδ15N） of organic matter in the surface sediment were determined. The results showed that, in August, sedimentary OC and TN ranged from 0.17% to 0.76% and 0.04% to 0.14%, respectively. In November, OC and TN ranged from 0.23% to 0.87% and 0.05% to 0.14%, respectively. There was a significant positive correlation between OC and TN （R=0.98, P＆lt;0.0001）, indicating that OC and TN were homologous. In August, theδ13C andδ15N of organic matter varied from -23.06‰ to -21.59‰ and 5.10‰ to 6.31‰, respectively. In November,δ13C andδ15N ranged from -22.87‰ to -21.34‰ and 5.13‰ to 7.31‰, respectively. This study found that the major sources of sedimentary organic matter were marine shellfish biodeposition, seaweed farming, and soil organic matter. Using a three-end-member mixed model, we estimated that the dominant source of sedimentary organic matter was shellfish biodeposition, with an average contribution rate of 65.53% in August and 43.00% in November. Thus, shellfish farming had a significant influence on the coastal carbon cycle.
基金The National Basic Research Program(973 Program)of China under contract No.2010CB428902the Special Scientific Research Funds for Central Non-profit Institutes,Chinese Academy of Fishery Sciences under contract No.2014A01YY01the Management of Central Public-interest Scientific Institution Basal Research Fund under contract No.20603022013003
文摘In this study, we assessed the burial fluxes and source appointment of different forms of carbon in core sediments collected from culture areas in the Sanggou Bay, and preliminarily analyzed the reasons for the greater proportion of inorganic carbon burial fluxes （BFTIc）. The average content of total carbon （TC） in the Sanggou Bay was 2.14%. Total organic carbon （TOC） accounted for a small proportion in TC, more than 65% of which derived from terrigenous organic carbon （Ct）, and while the proportion of marine-derived organic carbon （Ca） increased significantly since the beginning of large-scale aquaculture. Total inorganic carbon （TIC） accounted for 60%-75% of TC, an average of which was 60%, with a maximum up to 90% during flourishing periods （1880-1948） of small natural shellfish derived from seashells inorganic carbon （SheU-IC）. The TC burial fluxes ranged from 31 g/（m2.a） to 895 g/（m2.a） with an average of 227 g/（m2.a）, which was dominated by TIC （about 70%）. Shell-IC was the main source of TIC and even TC. As the main food of natural shellfish, biogenic silica （BSi） negatively correlated with BFTIc through affecting shellfish breeding. BFTIc of Sta. S1, influenced greatly by the Yellow Sea Coastal Current, had a certain response to Pacific Decadal Oscillation （PDO） in some specific periods.
基金The National Basic Research Program of China(973 Program)under contract No.2011CB409802the National Natural Science Foundation of China under contract No.41521064+1 种基金the Taishan Scholars Program of Shandong Province of Chinathe Aoshan Talents Program Supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2015ASTP-OS08
文摘The phosphorus cycle is studied during 2013–2014 in the Sanggou Bay（SGB）, which is a typical aquaculture area in northern China. The forms of measured phosphorus include dissolved inorganic phosphorus（DIP）, dissolved organic phosphorus（DOP）, particulate inorganic phosphorus（PIP）, and particulate organic phosphorus（POP）.DIP and PIP are the major forms of total dissolved phosphorus（TDP） and total particulate phosphorus（TPP）,representing 51%–75% and 53%–80%, respectively. The concentrations and distributions of phosphorus forms vary among seasons relative to aquaculture cycles, fluvial input, and hydrodynamic conditions. In autumn the concentration of DIP is significantly higher than in other seasons（P〈0.01）, and higher concentrations are found in the west of the bay. In winter and spring the phosphorus concentrations are higher in the east of the bay than in the west. In summer, the distributions of phosphorus forms are uniform. A preliminary phosphorus budget is developed, and shows that SGB is a net sink of phosphorus. A total of 1.80×10^7 mol/a phosphorus is transported into the bay. The Yellow Sea is the major source of net input of phosphorus（61%）, followed by submarine groundwater discharge（SGD）（27%）, river input（11%）, and atmospheric deposition（1%）. The main phosphorus sink is the harvest of seaweeds（Saccharina japonica and Gracilaria lemaneiformis）, bivalves（Chlamys farreri）,and oysters（Crassostrea gigas）, accounting for a total of 1.12×10^7 mol/a. Burial of phosphorus in sediment is another important sink, accounting for 7.00×10^6 mol/a. Biodeposition by bivalves is the major source of phosphorus in sediment, accounting for 54% of the total.
基金supported by the National Science and Technology Basic Resources Investigation Program of China(No.2018FY100206)the National Natural Science Foundation of China(Nos.31902370 and 42276099)+2 种基金the Ningbo Public Welfare Science and Technology Program(No.2022S161)the Key Program of Science and Technology Innovation in Ningbo(No.2023Z118)the National Key Research and Development Program of China(No.2018YFD0900703).
文摘Integrated multi-trophic aquaculture(IMTA)has been considered as an ecofriendly culture system providing a potential solution to environmental risks caused by intensive monoculture system.However,the impact of IMTA on phytoplankton remains unclear.In this study,the spatial and temporal variations of phytoplankton in Sanggou Bay were investigated seasonally based on 21 sampling sites covering three cultivation zones(bivalve zone,IMTA zone,and kelp zone)and one control zone(without aquatic cultivation).In total,128 phytoplankton species,with diatoms and dinoflagellates as the dominant groups,were obtained across the whole year,and the mean Shannon diversity index(H')and species richness(SR)were determined as 1.39 and 9.39,respectively.The maximum chlorophyll a(Chl-a)(6.32μg L^(-1))and plankton diversity(H'of 1.97)occurred in summer and autumn,respectively.Compared to other zones,the bivalve zone displayed significantly higher Chl-a and lower H'in majority of time.Pairwise PERMANOVA analysis indicated that the phytoplankton assemblage in the bivalve zone was significantly different with the control and kelp zones,while the IMTA zone maintained close to other three zones.Based on generalized additive models,temperature,NO_(2)^(-)-N,N/P ratio,SiO_(3)^(2-)-Si,and salinity were determined as the key factors underlying Chl-a and phytoplankton diversity.Addi-tionally,the results of redundancy analysis further indicated that the phytoplankton assemblage in the bivalve zone is positively re-lated with nutrients such as NO_(3)^(-)-N and NH_(4)^(+)-N as well as water depth,while the phytoplankton assemblages in the kelp,control,and IMTA zones are associated with NO_(2)^(-)-N,SiO_(3)^(2-)-Si,and salinity.Taken all observations into consideration together,it can be inferred that IMTA can effectively reduce Chl-a level compared to bivalve monoculture by reducing the nutrients.However,the SR,H’,and species composition of phytoplankton are primarily determined by local environment factors such as temperature,water depth,salinit
基金This study was supported by EC Project under contract No.ERB3514PL97 2439 with the contract No.ERB IC18-CT98-0291.
文摘The standing crop and primary production of benthic microalgae on tidal flats have seasonally been observed in the Sanggou and Jiaozhou Bays of the northern China coast during 1999 - 2000. The results show that the annual primary productions of benthic microalgae on tidal flats in the two bays are 2 532 and 7 542 tons carbon, which would be able to support 3.1 x 103 and 9.2 x 103 tons shellfish meat, respectively. The nature of sediment is essential for governing the biomass and primary production of benthic microalgae on tidal flats. The biomass and primary production of benthic microalgae on tidal flats with muddy sediments are higher than those with sandy sediments, which resulted from higher nutrient concentration and lower grazing pressure. That is the reason why in comparison with Xiangshan Bay the standing crop and production of benthic microalgae on tidal flats of the Sanggou and Jiaozhou Bays are low. Light was a key factor controlling vertical distribution of biomass and production of benthic microalgae on tidal flats of the two bays, resulted in appearance of maximum chlorophyll a and primary production at the surface layer and sharply decreased with depth of sediment.
基金Acknowledgments This work was supported by the National Basic Research Program of China （Grant No. 2011 CB409805）, the National Science and Technology Planning Project of China （Grant No. 2011BAD13B05）, the National Natural Science Foundation of China （Grant No. 41006074） and theSpecial Project of State Oceanic Administration （Grant No. DOMEP （MEA）-02）. The authors were grateful to Mr. Zhang Huayue of Xunshan Fishery Group for his cooperation along this work and also to the very constructive comments by several reviewers.
文摘The sediment resuspension mechanisms in Sungo Bay, a large-scale aquaculture area in north China, were investigated by analysing data collected during several periods from 2005 to 2006. Nortek 6M ADV current meter and YSI6600 were used to collect the field data on current speed, current direction and water turbidities 1 m above the bottom. Based on the collected field data, it could be found that wind-waves and currents were the main driving force for sediment resuspension. The correlation between suspended sediment concentration （SSC） and turbidity （NTU） is SSC = 15.908 x In （NTU） ＋ 7.0888 （n = 33, R2 = 0.7209）. Taking the key factor （angle 0） into account, the combination effect between wave and current were expressed. Results showed that the combined shear stress （row） of wave stress （re） and current stress （rw） could be calculated by row = rc ＋ 2√ rcrw sin θ ＋ rw sin^2 θ. The critical shear stress for sediment resuspension was about 0.059 N/m^2. The correlation between suspended sediment concentration and critical shear stress could be expressed by rcw = 238.06 SSC ＋ 25.215 （n = 25, R^2 = 0.7298）.
