作者: Mary E Russ , Nathaniel E Ostrom , Hasand Gandhi , Peggy H Ostrom , Noel R Urban
DOI: 10.1029/2003JC001890
关键词:
摘要: [1] A study of respiration to photosynthesis (R:P) ratios in Lake Superior, based on the fraction O2 saturation and isotopic composition O2, was undertaken evaluate spatial temporal variations trophic status a large oligotrophic freshwater environment. The lake predominantly net heterotrophic from April October 2000 (R:P ratios: 1.2–2.5). Uniform R:P ∼1.5 with depth across 2001 revealed homogeneity water column during spring. A brief period autotrophy observed summer thermal stratification 2001, surveys showed this condition be prevalent lake-wide August 0.5–0.9). Strong 0.6) found near Duluth, Minnesota, suggested potential for formation mesotrophic conditions within areas increased nutrient loadings urbanization. Respiration were shown exert strong control gas exchange as evidenced by significant correlations between periods heterotrophy autotrophy. This observation unexpected since [O2] appears dominated atmospheric exchange, given that is continuously levels expected equilibration atmosphere. Furthermore, relationship biological physical fluxes may enable use calculate ultimately estimate CO2 lakes