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1.
The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to ...  相似文献   

2.
Zhang  Anqi  Liu  Honghan  Li  Chenhong  Chen  Changping  Liang  Junrong  Sun  Lin  Gao  Yahui 《中国海洋湖沼学报》2022,40(6):2401-2415

Toxic and harmful algal blooms are usually more frequent in mariculture areas due to the abundant trophic conditions. To investigate the relationship between toxic and harmful microalgae and environmental factors, we set up 12 stations near three mariculture regions (Gouqi Island, Sandu Bay, and Dongshan Bay) in the East China Sea. We collected samples from all four seasons starting from May 2020 to March 2021. We identified 199 species belonging to 70 genera, of which 38 species were toxic and harmful, including 24 species of Dinophyceae, 13 species of Bacillariophyceae, and 1 species of Raphidophyceae. The species composition of toxic and harmful microalgae showed a predominance of diatoms in the summer (August), and dinoflagellates in the spring (May), autumn (November), and winter (March). The cell densities of toxic and harmful microalgae were higher in summer (with an average value of 15.34×103 cells/L) than in other seasons, 3.53×103 cells/L in spring, 1.82×103 cells/L in winter, and 1.0×103 cells/L in autumn. Pseudonitzschia pungens, Prorocentrum minimum, Paralia sulcata, and Prorocentrum micans were the dominant species and were available at all 12 stations in the three mariculture areas. We selected 10 toxic and harmful microalgal species with frequency >6 at the survey stations for the redundancy analysis (RDA), and the results show that NO ?3 , water temperature (WT), pH, DO, and NO ?2 were the main factors on distribution of toxic and harmful microalgae. We concluded that the rich nutrient conditions in the East China Sea mariculture areas increased the potential for the risk of toxic and harmful microalgal bloom outbreaks.

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3.
To understand the factors causing frequent outbreaks of harmful algae blooms in the Taihu Lake, China, we studied water quality and nutrient budget in Chinese mitten crab (Eriocheir sinensis) farm ponds in the eastern part of the lake from November 2007 to December 2009. We estimated the nitrogen (N), phosphorus (P), and chemical oxygen demand (COD) loads. Materials input and output ponds, water exchange, and applied management practices of 838.5-hm2 crab ponds were surveyed using questionnaires. Water quality of 12 ponds, which were located no more than 2 km from East Taihu Lake, were monitored. The results show that water quality in the crab ponds was better than reference data. Feeds, including corn seed, commercial feed, trash fish, and gastropod, were the major sources of N and P input in the crab ponds, contributing 88.7% and 94.9%, respectively. In total, 60.5% of N and 37.3% of P were sequestered by macrophytes, and only 15.7% and 8.5% of them were discharged as effluent. The net loads of N and P in effluent were 16.43 kg/hm2/cycle and 2.16 kg/hm2/cycle, respectively, while the COD load was -17.88 kg/hm2/cycle. This indicated that crab farming caused minor negative impact on the trophic status of the lake area, which was attenuated by macrophytes. However, wastewater purification is still necessary in crab faming.  相似文献   

4.
The acute toxic levels of formalin to a marine red-tide dinoflagellate Prorocentrum minimum Schiller (Mastigophora, Dinoflagellida) were determined by linear regression analysis. The data obtained revealed that there is a close regression relationship between logarithmic concentrations of formalin and mortality probit scales of the organism when exposure times are 1, 2, 6, 12, 24 h. The median lethal concentrations (LC50 values) obtained from correlation analysis for these exposure times (with 95% confidence intervals), were 11.83, 6.76, 4.37, 4.27 and 3.98mgL^-1 respectively. A toxicity curve was obtained to connect the exposure time and LC50 value from the correlation between them. The results indicated that P. minimum could be killed or fixed by formalin in the concentration range of 4-12mgL^-1 within 1-24h.  相似文献   

5.
To understand the characteristics of macrobenthic structures and the relationship between environment and benthic assemblages in jellyfish bloom, we studied the macrobenthos and related environmental factors in the coastal waters of the Yellow Sea and East China Sea. Data were collected during two seasonal cruises in April and August of 2011, and analyzed with multivariate statistical methods. Up to 306 macrobenthic species were registered from the research areas, including 115 species of Polychaeta, 78 of Crustacea, 61 of Mollusca, 30 of Echinodermata, and 22 of other groups. Nine polychaete species occurred at frequencies higher than 25% from the sampling stations： Lumbrineris longifolia, Notomastus latericeus, Nin6e palmata, Ophelina acuminata, Nephtys oligobranchia, Onuphis geophiliformis, Glycera chirori, Terebellides stroemii, and Aricidea fragilis. Both the average biomass and abundance of macrobenthos are higher in August （23.8 g/m^2 and 237.7 ind./m^2） than those in April （11.3 g/m^2 and 128 ind./m^2）; the dissimilarity ofmacrobenthic structures among stations is as high as 70%. In terms of the dissimilarity values, we divided the stations into four clusters in spring and eight in summer. The ABC curve shows that the macrofauna communities in high jellyfish abundance were not changed. Canonical correspondence analysis showed that depth, temperature, median grain size, total organic carbon of sediment and total nitrogen in sediment were important factors affecting the macrozoobenthic community in the study area.  相似文献   

6.
The distributions of N utilizing bacteria (denitrifying bacteria and ammonifying bacteria), P utilizing bacteria (organic phosphobacteria and inorganic phosphobacteria) and heterotrophic bacteria in the Changjiang Estuary, and the roles of main environmental factors in distributing bacteria, are explored with observations from two cruises in June and August 2006. Comparisons between the two important periods of initial hypoxia phase (June) and developed hypoxia phase (August) show differences in both bacterial distributions and the associated main environmental factors. First, the primary group of ammonifying bacteria has larger magnitude with spatial maximum value in the hypoxic stations related to sediment in August. The phosphobacterial abundance and detection rates in August are much lower than those in June, but the denitrifying bacterial abundance becomes greater in August. However, the difference of heterotrophic bacterial abundance between June and August is not obvious. Second, main environmental factors influencing bacteria vary from initial hypoxia phase to developed hypoxia phase. Two parameters (salinity and NO3 ?) in surface water and five environmental parameters (pH, salinity, PO4 3?, NO3 ? and temperature) in bottom water and surface sediment play major roles in the bacterial abundance in June, while different parameter combinations (salinity and PO4 ?) in surface water and different parameter combinations (DO, DOC, NO3 ?, PO4 3? and pH) in bottom water and surface sediment play major roles in August. Moreover, the bottom bacteria distributions in area south of 31°N are related to the position of the Taiwan Warm Current in June. The bacterial abundance and distribution may respond to the environmental change in the hypoxia processes of initial phase and developed phase. During the hypoxia processes, the whole structure of bacterial functional groups probably turns to different states, causing the recycling of nutrient regeneration and aggravating hypoxia regionally.  相似文献   

7.
In the high mountain oligotrophic Seven Rila Lakes (2 095–2 535 m a.s.l.) bacterial abundance was recorded in July and September 2006. In July, bacterial abundance (average (3.32±2.5)×105 cell/ml) in the lakes correlated negatively with elevation, while in September (average (26.39±7.1)×105 cell/ml) this pattern was altered and the greatest abundance of bacteria occurred at the highest ((39.05±1.5)×105 cell/ml) and the lowest ((30.63±6.0)×105 cell/ml) elevated lakes. Regression analyses suggested that the principal factor controlling bacterial abundance, in both July and September, was inorganic nitrogen (NO3-N and NH4-N; R 2=0.70, P<0.05). Other major regulating factors were temperature (R 2=0.66, P<0.03) in July and filter-feeding zooplankton (R 2=0.95, P<0.01) in September. All factors, except NO3-N, had a positive effect on bacterial abundance.  相似文献   

8.
Three surveys were carried out in Pearl River Estuary and adjacent coastal area in May, August, and November, 2013, to investigate the temporal and spatial variations of abundance of phycoerythrin-rich Synechococcus (PE-rich SYN) and phycocyanin-rich Synechococcus (PC-rich SYN). The effects of environmental factors on the alternation of the different Synechococcus groups were also elucidated. PE-rich SYN was detected in three surveys, whereas PC-rich SYN was detected in May and August, but not in November. The highest abundances of PE-rich SYN and PC-rich SYN were recorded in August and May, with mean values of 74.17×103 and 189.92×103 cells mL?1, respectively. From May to November, the relative abundance of PE-rich SYN increased, whereas that of PC-rich SYN declined. PE-rich and PC-rich SYN presented similar horizontal distributions with high abundance in the southern estuary in May, and in the western estuary in August. The abundances of PE-rich and PC-rich SYN were high at 27–32°C and salinity of 10–20. PC-rich SYN was not detected at < 24°C, and PC:PE-rich SYN decreased in abundance with salinity increase. When less than 20 mg L?1, suspended particulate matter (SPM) was helpful for Synechococcus growth. PE-rich SYN decreased in abundance when the concentration of dissolved inorganic nitrogen increased in May and November, and the concentration of phosphate increased in November. However, PC-rich SYN abundance and nutrients showed no correlation. Principal component analysis and regression analysis indicated that PE-rich SYN significantly correlated with the principal components that were affected by environmental factors.  相似文献   

9.
Morphotaxonomy and seasonal abundance of dinoflagellates of the genera Prorocentrum and Mesoporos(Prorocentrales) were studied from nutrient-rich waters,Karachi Harbor and the mouth of the Manora Channel,Pakistan during May 2002-July 2003.Using both light and scanning electron microscopy,13 species of Prorocentrales were identified according to cell shape,size,ornamentation of thecal plates,and architecture of apical platelets,apical pore area,marginal pores,and intercalary bands.P.sigmoides,P.arcuatum,P.scutellum,P.donghaiense,P.balticum,P.minimum,P.emarginatum,P.lima,P.faustiae,and Mesoporos perforatus constitute new records for sindh coast of Pakistan.The most abundant species were P.minimum/P.balticum(4.5×103 cells/L),P.micans(1.1×103 cells/L),P.gracile/P.sigmoides(2.5×102 cells/L) and P.donghaiense(6.6×103 cells/L) at temperatures of 29-31℃ and salinities of 35-40.Maximum abundance was observed in winter and lower abundance in summer.There was no significant change in the distribution of species between stations except for the benthic species which occurred close to Karachi Harbor waters.Significant positive correlations were observed between Prorocentrum spp.and temperature(R 2 =0.27) and negative correlations with salinity(R 2 =-0.32) except for P.minimum and P.emarginatum which has negative correlation with temperature(R 2 =-0.24) and positive with salinity(R 2 =0.08,0.19).The finding of potential okadaic-acid producing species of benthic Prorocentrum call for monitoring for possible human health problems in this region.  相似文献   

10.
The abundance and biomass of benthic heterotrophic bacteria were investigated for the 4 typical sampling stations in the northern muddy part of Jiaozhou Bay, estuary of the Dagu River, raft culturing and nearby areas of Huangdao in March, June, August and December, 2002. The abundance and biomass range from 0.98×107 to 16.87×107 cells g−1 sediment and 0.45 to 7.08 μg C g−1 sediment, respectively. Correlation analysis showed that heterotrophic bacterial abundance and biomass are significantly correlated to water temperature (R=0.79 and 0.83, respectively,P<0.01).  相似文献   

11.
Dimethylsulfide(DMS) and dimethylsulfoniopropionate(DMSP) production by Scrippsiella trochoidea and Prorocentrum minimum was investigated to characterize the effects of physiological stage and salinity on DMS and DMSP pools of these two marine phytoplankton species.Axenic laboratory cultures of the two marine algae were tested for DMSP production and its conversion into DMS.The results demonstrated that both algal species could produce DMS,but the average concentration of DMS per cell in S.trochoidea(12.63 fmol/L) was about six times that in P.minimum(2.01 fmol/L).DMS and DMSP concentrations in algal cultures varied significantly at different growth stages,with high release during the late stationary growth phase and the senescent phase.DMS production induced by three salinities(22,28,34) showed that the DMS concentrations per cell in the two algal cultures increased with increasing salinity,which might result from intra-cellular DMSP up-regulation with the change of osmotic stress.Our study specifies the distinctive contributions of different physiological stages of marine phytoplankton on DMSP and DMS production,and clarifies the influence of salinity conditions on the release of DMS and DMSP.As S.trochoidea and P.minimum are harmful algal bloom species with high DMS production,they might play an additional significant role in the sulfur cycle when a red tide occurs.  相似文献   

12.
Nutrient and Chlorophyll-a (Chl-a) concentrations were investigated monthly along three transects extending from a mariculture area to open waters around the Zhangzi Island area from July to December 2009. The objective of this study is to illustrate food availability to the bottom-sowed scallop Patinopecten yessoensis under the influences of the Yellow Sea Cold Water Mass (YSCWM), freshwater input and feedbacks of cultivated scallops. Significant thermal stratification was present in open waters from July to October, and salinity decreased in July and August in surface layers in the mariculture area. Nutrient concentrations increased with depth in both areas in summer, but were similar through water column in November and December. On average, nutrient increased from summer to autumn in all components except ammonia. Nutrient concentrations lower than the minimum thresholds for phytoplankton growth were present only in upper layers in summer, but stoichiometric nitrogen limitation existed in the entire investigation period. Column-averaged Chl-a concentration was lower in open waters than in mariculture area in all months. It increased significantly in mariculture area in August and October, and was less variable in open waters. Our results show that nutrients limitation to phytoplankton growth is present mainly in upper layer in association with stratification caused by YSCWM in summer. Freshwater input and upwelling of nutrients accumulated in YSCWM can stimulate phytoplankton production in mariculture area. Farming activities may change stoichiometric nutrient ratios but have less influence on Chl-a concentration.  相似文献   

13.
The temporal dynamics of the biomass, as well as the carbon (C), nitrogen (N), phosphorus (P) concentrations and accumulation contents, in aboveand below-ground vegetation components were determined in the alpine steppe vegetation of Northern Tibet during the growing season of 2010. The highest levels of total biomass (311.68 g m−2), total C (115.95 g m−2), total N (2.60 g m−2), and total P (0.90 g m−2) accumulation contents were obtained in August in 2010. Further, biomass and nutrient stocks in the below-ground components were higher than those of the above-ground components. The dominant species viz., Stipa purpurea and Carex moorcrofti had lower biomass and C, N, P accumulations than the companion species which including Oxytropis. spp., Artemisia capillaris Thunb., Aster tataricus L., and so on.  相似文献   

14.
Variations in physical-chemical factors, species composition, abundance and biomass of nano- and micro-phytoplankton assemblages, as well as their responses to environmental factors, were investigated over a complete cycle (6 months) in a semi-enclosed shrimp-farming pond near Qingdao, northern China. The aim was to establish the temporal patterns of phytoplankton communities and to evaluate protists as suitable bioindicators to water quality in mariculture systems. A total of 34 taxa with nine dominant species were identified, belonging to six taxonomic groups (dinoflagellates, diatoms, cryptophyceans, chlorophyceans, euglenophyceans and chrysophyceans). A single peak of protist abundance occurred in October, mainly due to chlorophyceans, diatoms and chrysophyceans. Two biomass peaks in July and October were primarily due to dinoflagellates and diatoms. Temporal patterns of the phytoplankton communities significantly correlated with the changes in nutrients, temperature and pH, especially phosphate, either alone or in combination with NO3-N and NH3-N. Species diversity, evenness and richness indices were clearly correlated with water temperature and/or salinity, whereas the biomass/abundance ratio showed a significant correlation with NO3-N. The results suggest that phytoplankton are potentially useful bioindicators to water quality in semi-enclosed mariculture systems.  相似文献   

15.
The rapid development of mariculture in China in recent decades has satisfied people's demand of seafood, and has made a great contribution to economic development. However, mariculture has also caused some negative impacts on the eco-environment. By statistically analyzing national data(as well as data for four main provinces) regarding the mariculture area and cultivation species in China since reform and opening up, the historical evolution of mariculture during the past 40 years was analyzed, the driving factors related to policy, market and technology innovation were discussed, and the potential impacts of mariculture on the coastal eco-environment were also illustrated. The statistical results indicated that the maricultural area increased radically during the past 40 years, from 1979(116.47 × 10~3 ha) to 2012(2205.65 × 10~3 ha), with an increase of nearly 20-fold. Shandong Province represented the fastest-growing region, with an increase of 31-fold. Moreover, the cultivated species had gradually become diversified. Initially, shellfish and algae were major species, and then it developed to various species including fish, and currently shellfish and crustaceans were the major species. The development of mariculture was driven by government policies, market economy and technology innovation. Rapid development of mariculture also caused significantly adverse impacts on the eco-environment of the coastal regions. For example, the sea reclamation for mariculture decreased the area and function of coastal wetlands and the contaminants originating from mariculture destroyed the coastal aquatic environment. Fortunately, the implementation of ‘13 th Five-Year Fisheries Planning' is expected to help both improve the seafood quality and reduce the contamination in coastal aquatic environment. This current study will provide reference for management and structure adjustment of mariculture in the future.  相似文献   

16.
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17.
The dinoflagellate Prorocentrum minimum, one of the most widespread red tide causing species, affects marine aquaculture and ecosystems worldwide. In this study, ridgetail white prawn Exopalaemon carinicauda were exposed to P. minimum cells (5 × 104 cells mL?1) to investigate its harmful effects on the shrimp. Antioxidant activities and histological changes were used as indicators of health status of the shrimp. In 72 hours, the mortality of E. carinicauda was not affected, but its antioxidant response and histology were statistically different from those of control. Elevated superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities and depressed catalase (CAT) activity were observed in gill; while increased SOD, glutathione S-transferase (GST), CAT activities and modulated GPX activity were observed in hepatopancreas. Thus, antioxidant activities in gill and hepatopancreas seem to respond differentially to harmful alga exposure. Increased malondialdehyde (MDA) content in early a few hours indicates the damage of the antioxidant defense system. Although MDA content recovered to a low level thereafter, a series of histological abnormalities including accumulation or infiltration of hemocytes, tissue lesions and necrosis were discovered in gill and hepatopancreas. Exposure to P. minimum induced sublethal effects on E. carinicauda, including temporary oxidative damage and histological injury.  相似文献   

18.
The species composition and abundance of microzooplankton at 10 marine and five coastal stations(Hongdao,Daguhe,Haibohe,Huangdao and Hangxiao) in the Jiaozhou Bay(Qingdao,China) were studied in 2001.The microzooplankton community was found to be dominated by Tintinnopsis beroidea,Tintinnopsis urnula,Tintinnopsis brevicollis and Codonellopsis sp.The average abundance of microzooplankton was highly variable among stations.Specifically,the abundance of microzooplankton was higher at inshore stations and lower ...  相似文献   

19.
Dilution incubations and Calanus sinicus addition incubations were simultaneously conducted at five stations in the Yellow Sea in June of 2004 to evaluate the impact of microzooplankton and Calanus sinicus on phytoplankton based on the Chlorophyll a (Chl-a) levels. The Chl-a growth rates (k) ranged from 0.60–1.67 d−1, while microzooplankton grazed the Chl-a at rates (g) of 0.29–0.62 dt-1. The addition of C. sinicus enhanced the Chl-a growth rate (Z) by 0.004–0.037 d−1 ind.−1 L. C. sinicus abundance ranged from 84.1–160.9 ind. m−3, which occupied 90.7%–99.1% of the copepod (>500 μm) population. The in-situ increase in phytoplankton by C. sinicus community was estimated to be 0.000 4–0.005 9 d−1. These results showed that microzooplankton were the main grazers of phytoplankton, while C. sinicus induced a slight increase in the levels of phytoplankton.  相似文献   

20.
Two modes of regulating the water quality of experimental ponds in indoor raceway culture of Litopenaeus vannamei were evaluated using simple water treatment facilities. A self-made water purifying net, aeration stone, composite microbe preparation, and Ceratophyllum demersum were placed in the experimental ponds and the culture water was circulated along the raceway inside the pond using a paddle wheel aerator. In addition, the water quality in the experimental pond was improved by draining effluent from the pipeline at the bottom of ponds 7 and 8 (mode I) and exchanging the circulating water in pond 10 (mode II) with the reservoir water in pond 9 using a pump and pipeline. The water quality in the experimental ponds was similar in response to regulation using mode I or mode II. Water quality parameters in the experimental ponds were controlled within a suitable range by simple facilities during culture period without using any chemical treatments. The rich content of dissolved oxygen was maintained by the circular flow and continuous aeration of the pond water. The respective average values of the main water parameters in experimental ponds 7 and 10 in response to regulation of the water quality using modes I and II were as follows: pH 8.17 and 7.99; DO 5.16 mg/L and 5.97 mg/L; CODMn 18.45 and 12.61 mg/L; TAN (NH3-N) 0.854 mg/L (0.087 mg/L) and 0.427 mg/L (0.012 mg/L); NO2-N 0.489 mg/L and 0.337 mg/L. Moreover, the average body length and body weight of harvested shrimp of pond 7 and pond 10 were 7.56 cm and 8.99 cm, 5.10 g and 8.33 g, respectively. Furthermore, the survival rate, average biomass yield and average condition factor of the shrimp harvested were 70% and 60%, 2.54 kg/m2 and 2.14 kg/m2, and 0.675 g/cm and 0.927 g/cm, respectively. Linear equations describing the relationship between body length and culture time and cubic or power functions describing the relationship between body weight and body length were obtained based on evaluation of the growth data of shrimps throughout the culture period.  相似文献   

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