Nutrient concentrations uptake

N S sulphur relations in soft white winter wheat. II. Initial and residual effects of S application on nutrient concentration uptake and N S ratio. Agronomy Journal, 67, 224-228. 

Silicic acid (H4Si04) is a necessary nutrient for diatoms, who build their shells from opal (Si02 H20). Whether silicic acid becomes limiting for diatoms in seawater depends on the availability of Si relative to N and P. Estimates of diatom uptake of Si relative to P range from 16 1 to 23 1. Dugdale and Wilkerson (1998) and Dunne et al. (1999) have shown that much of the variability in new production in the equatorial Pacific may be tied to variability in diatom production. Diatom control is most important at times of very high nutrient concentrations and during non-steady-state times, perhaps because more iron is available at those times. 

Table 1 Discharge, nutrient concentrations, and nutrient uptake lengths for ammonium, nitrate, and phosphate measured at reaches located upstream (UP) and downstream (DW) of WWTP effluent inputs in flve European streams... 

Nutrient concentration has a marked seasonal variation in the middle Ebro. Nutrient loads transported by the river are relevant during the high flow season (December-April), while nitrate inputs from agriculture can also be relevant. In this period, crop fertilization is carried out, precipitation is higher, and plant nitrogen uptake is lower [37], Although nutrient loads are high, dilution causes NO3 and... 

Bode, A., Gonzalez, N., Rodriquez, C., Varela, M., and Varela, M. M. (2005). Seasonal variabflity of plankton blooms in the Ria de Ferrol (NW Spain). I. Nutrient concentrations and nitrogen uptake rates. Estuar. Coast. Shelf Sci. 63, 269—284. 

Most of the water masses in the Baltic Sea are found above the halocline, e.g., in the Baltic Proper only 20% of the volume is below the halocline. Deep-water entrainment and especially internal nutrient turnover processes (phytoplankton uptake, N2 fixation, sedimentation, denitrification) have a profound influence on concentrations in surface water. Decreases in nutrient concentrations in surface waters of the Baltic Sea have been interpreted as consequences of reduced external loading. However, the total amount of N and P in the water mass and active... 

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