Characterization of dissolved inorganic carbon and dissolved oxygen in two impacted Amazonian lakes

[摘要] Six surface water campaigns were carried out in lakes Bolonha-LB and Agua Preta-LAP(Brazil) during 2018- 2019. Temporal and spatial variations of temperature, pH, electricalconductivity, dissolved oxygen(DO), total alkalinity (TA), turbidity, dissolved carbon dioxide(COza), and partial pressure of CO,(pCOz) were analyzed and estimated. High levels of COza,were observed during the study (104 - 998 umol l"'),while CO2e, in equilibrium with theatmosphere ranged between 11.5 and 12.3 umol l'. The pCO2 values ranged from 3,400 to23,600 uatm. DO ranged from 1.0 - 8.5 mg l' and showed significant spatial differences (p production).The analysis of the relationships between AOU and excess CO indicated that about 65% of thecarbon mineralization in the lakes is anaerobic，indicating the predominance of the respirationprocess in the systems studied. A comparative analysis with other 117 tropical lakes showed thatLAP and LB are part of the 78% of lakes with CO supersaturation. This work showed that: theheterotrophic processes identified during this study are mainly a product of the inorganiccontributions of organic matter from the adjacent urban region.

[学科分类] 天文学(综合)

[关键词] carbonate system;DIC;dissolved carbon;AOU;tropical lakes