Environmental characteristics of annual pico/nanophytoplankton blooms along the Qinhuangdao Coast

Abstract Blooms of some pico/nanophytoplankton have occurred frequently along the Qinhuangdao coast since 2009, and it is necessary to identify the critical environmental factors inducing them. In this study, variations in the physical and nutrient characteristics of the seawater were analyzed following the development of local blooms in 2013. The local environmental characteristics were also compared with those of the Changjiang River estuary, China, and the Long Island estuaries in the USA, which are also prone to blooms of special algal species. In Qinhuangdao the local water temperature varied seasonally and rose above 15~C in 2013 early summer, coincident with the water discoloration. The salinity was more than 28 with a variation range of 〈3 throughout the year. Our results suggest that the physical conditions of the Qinhuangdao coastal area were suitable for the explosive proliferation of certain pico/nanophytoplankton, e.g. Aureococcus anophagefferens. The water supporting the bloom was not in a condition of serious eutrophication, but there were relatively high concentrations of reduced nitrogen （especially ammonium）, which acted as an important nitrogen source for the pico/nanophytoplankton bloom. There was also a large gap between total nitrogen （TN） and dissolved inorganic nitrogen （DIN）. Although the phosphate concentration was relatively low, there was no evidence of phosphorus limitation to the growth of pico/ nanophytoplankton during bloom events.

Silicon limitation on primary production and its destiny in Jiaozhou Bay, China VI: The ecological variation process of the phytoplankton

The combination effect of light, water temperature and nutrients on phytoplankton growth in Jiaozhou Bay is studied in this paper. The order of importance of the influence on phytoplankton growth is de- termined as nutrients, water temperature, and light. The influence of these factors unveiled the mechanism of the influence, and revealed the variation process of the nutrients limiting phytoplankton primary production, and of the water temperature influencing the phytoplankton reproduction capacity, and hence influencing the structure of phytoplankton assemblage. Temporal and spatial quantification shows different stages of the influence by wa- ter temperature and nutrients on the phytoplankton growth. Moreover, the authors expatiated the ideal state of the phytoplankton growth and the reason of red tide occurrence. People should consider in their activity the input of nutrient Si first, and then the variation of water temperature, advocating sustainable development manner.

Detection of Phaeocystis globosa using sandwich hybridization integrated with nuclease protection assay(NPA-SH)

Phaeocystis globosa Scherffel is one of the common harmful algae species in coastal waters of the southeastern China.In this study,sandwich hybridization integrated with nuclease protection assay(NPA-SH)was used to qualitatively and quantitatively detect P. globosa.Results showed that this method had good applicability and validity in analyzing the samples from laboratory cultures and from fields.The linear regression equation for P.globosa was obtained,and the lowest detection number of cells was 1.8×104 c...

The study on the effect of NO on the growth of Chaetoceros curvisetus

This article studied nitric oxide (NO) effect on the growth of Chaetoceros curvisetus in chemistry for the first time. Nitric oxide was added into the media with 4 different nutrient concentrations f/2, f/50, f/100, and f/200 when the alga was growing. The growth of C. curvisetus could be obviously promoted or inhibited during the cultivation process in NO enriched media of different concentrations. The growth curve in such media showed a sharp single peak that is the optimal NO concentration for the alga growth, which is consistent with the influence of NO on the growth of high plants. In addition, C. curvisetus can produce NO by itself during the growth. Therefore, using NO could effectively regulate the algae growth, which is important in real tide control and remediation.

Risk associated with toxic blooms of marine phytoplankton functional groups on Artemia franciscana

Objective:To study mortality of copepod Artemia franciscana against the occurrence of harmful marine algae and possible toxicological changes exhibited by binary and tertiary combinations of these harmful algae toxins.Methods:Tweenty four hours acute toxicity assays were performed with selected concentrations of Alexandrium minutum,Prorocentrum lima and Nitzschia N1c1 living cells.Additionally,the results were analyzed using the median-effect/combination index(CI)-isobologram equation to assess possible changes in the toxic effect induced by phytoplankton functional groups.Results:Biotoxin equivalent values obtained by immunodetection were(2.12±0.10),(8.60±1.30)and(4.32±1.67)pg/cell for saxitoxin,okadaic acid and domoic acid,respectively.The 24-h LC_(50) values estimated to saxitoxin and okadaic acid equivalents were 4.06 and 6.27μg/L,significantly below the value obtained for Nitzschia N1c1,which was established at 467.33μg/L.CI analysis applied on phytoplankton assemblages showed that both ternary mixture as the binary combinations exhibited antagonic action on toxic effects in Artemia nauplii,which were significantly lower than the toxic effect exhibited by each species studied.Conclusions:These results show that,although these harmful algae represent a serious risk to estuarine zooplankton community,the presence of phytoplankton functional groups within the same bloom can reduce the potential risk compared to the expected risk when each of the phytoplankton groups are evaluated individually.