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The introduction of Artemia franciscana to the coastal areas of the Mekong Delta of Vietnam fulfills the country’s needs to develop aquaculture activities and helps poor salt farmers to improve their living standards. The successful production of Artemia depends on many factors such as temperature, salinity, soil nutrient status and management. Apart from weather conditions and technical aspects, nutrient management for optimal growth of beneficial algae is one of the keys determining the success or failure of Artemia production. In the early stage of Artemia cultivation, algal booms occur in the ponds of rich nutrients if Artemia larvae’s consumption does not keep up with the rate of algal growth. Algal blooms deprive Artemia from its oxygen requirement or lead Artemia to suffer from indigestion since the retention time of algae in Artemia’s digestive tract is too short for effective digestion. In the juvenile stage of Artemia, low algal growth often results in Artemia’s starvation. In order to achieve sustainable Artemia production, the present study was undertaken aiming at a complete understanding on how the prevailing conditions in Artemia ponds (e.g. submergence, extremely high salinity, daily raking of pond bottom sediment) affect the dynamics of nitrogen (N) and phosphorus (P) in the pond sediments and the water column. Equally, we wanted to assess which soil properties control the supply of these nutrients from pond sediments. In turn, the responses of algae to the availability of N and P released from the sediments were quantified to determine whether these elements are limiting the growth of algae. Next, we set up bioassays with algae, in which inorganic N or P was added in different combinations to find the levels of N and P required for optimal growth of beneficial algae in Artemia ponds. We could demonstrate that the hypersaline conditions existing in Artemia ponds do affect both N and P availability. Increasing salinity to 80 g L-1 reduced mineral N accumulation at an early stage of submergence. However, these adverse effects of high salinity on N mineralization are short-lived as net N mineralization rate recovered after two weeks of submergence. Some of the heterotrophic organisms present in these soils may apparently adapt to high salinity, since these soils had been permanently submerged with highly saline water during the subsequent Artemia cultivation cycles. Extremely high salinity enhanced P availability and mobility. When sediments were extracted with artificial sweater (Instant Ocean at 70g L-1, EC 84-94 dS m-1), the concentrations of Dissolved Reactive P (DRP) present in the water column were 1.5 to 3 fold above the concentrations of DRP in the extracts with lower salinity (EC 11-23 dS m-1). In the standing water column, a large amount of DRP was immobilized by soil microorganisms. In current Artemia cultivation practice, disturbing pond sediments as daily rake of the pond bottom to feed Artemia favours conditions for the release and maintenance of available N and P. Under these conditions, the availability of N and P to algae utilization can be reliably predicted based on some simple soil chemical tests: the presence of Dissolved Inorganic N (DIN) after submergence can be predicted from the amounts of labile soil organic N extractable by hot KCl (R2 = 0.67, P < 0.001); whereas the pools of Olsen-P and/or the concentrations of DRP measured in saline extracts after 24 h equilibration can serve to estimate the availability of P (R2 = 0.64, P < 0.001 and R2 = 0.84, P < 0.001, respectively). We inoculated the diatom Chaetoceros calcitrans in solutions extracted from Artemia pond sediments to investigate its growth in relation to the availability of N and P as measured in the Artemia pond sediments. Large ratios of DIN:DRP in the extracts, ranging between 80 and 520, showed that the sediments from the Artemia ponds are highly unbalanced with respect to N and P. After inoculation, DRP was quickly exhausted in all extracts revealing that P is a limiting nutrient for the growth of algae. Only the media with DRP concentrations above 0.1 mg P L-1 sustained a higher density and biomass of algae. An attempt was made to elucidate the role of other Dissolved Organic P species (DOP) as a P source for algae in environments depleted in DRP. However, this could not be clearly ascertained since the concentrations of DOP in the media were too low (< 0.05 mg P L-1) to meet the requirements of the algae. Finally we performed experiments to determine the required quantities and balanced ratios of N and P for algae growth. The diatom C. calcitrans was used again and inoculated in the sediment extracts, amended with inorganic N or P in different combinations. Again, algae growth resulted in an exhaustion of DRP in all media. Adding inorganic P stimulated algae to assimilate more N and resulted in increases in algal densities (R2 = 0.70, P < 0.001) and biomass (R2 = 0.68, P < 0.001). Alternately, adding inorganic N decreased algal production. The densities of algae decreased logarithmically when DIN:DRP ratios increased from 50 to 910. When DIN:DRP ratios exceed 150, algal densities and biomass were constantly low, regardless the availability of DRP. Below a ratio of DIN:DRP of 150, the densities and biomass of algae were strongly dependent on the initial concentrations of DRP. When DIN:DRP ratio in the water column drops below 150, increasing DRP will stimulate algae to take up more DIN; however, the N and P contents of algal biomass always maintained a balance between 12 and 23. This suggests that a ratio of N:P in the water column not too remote from 23 will be more optimal for algae growth. The present study reveals that the growth of algae in Artemia ponds is limited by P. As a whole, the data suggest that supplying DRP above 0.1 mg P L-1 and at the same time maintaining DIN:DRP ratios below 150 is suitable for the growth of C. calcitrans in Artemia ponds. In the early stage of Artemia cultivation, however, DIN:DRP ratios in the pond water drop below this value due to supplying inorganic P may bring a serious risk of algal blooms.