The input of nutrients by the Rhône river into the Mediterranean Sea: Recent observations and comparison with earlier data

摘要: The nutrient input by the Rhone river into Mediterranean Sea was measured from June 1994 to May 1995. various fractions of N and P (dissolved particulate, organic inorganic) as well chlorophyll dissolved silicate concentrations were twice a month at Arles, 40 km upstream mouth, in this period. In addition, some samples taken when high flood.The study shows that nitrogen is mainly present nitrate (76%). Dissolved particulate represent 8 9%, ammonium 5% nitrite 1% total respectively. Almost half phosphate phosphate, largest part which calcium-bound phosphate. Orthophosphate represents 31% phosphate.We estimated nitrogen, 115–127 kt y-1 (N), 6.5–12.2 (P) 135–139 (Si) different methods. For an annual 92.3 96.1 found, 1.3 1.5 nitrite, 6.3 6.7 ammonium, 9.7 9.8 5.3 12.7 nitrogen; for imput 2.7 3.0 orthophosphate, 1.7 & polyphosphate 2.5 7.5 While N-input form nitrate, large particulate-P. Comparisons previous estimations show mean concentration has increased about 50% during last two decades.