Carbon cycle for Lake Washington - a stable isotope study

Journal Article · Thu May 01 00:00:00 EDT 1986 · Limnol. Oceanogr.; (United States)

DOI:https://doi.org/10.4319/lo.1986.31.3.0596· OSTI ID:5221497

Quay, P D; Emerson, S R; Quay, B M; Devol, A H

The authors investigate the carbon cycle in Lake Washington for the year 1980 using monthly measurements of the dissolved inorganic carbon (DIC) and its /sup 13/C:/sup 12/C isotopic composition. Mass balances of DIC and its /sup 13/C:/sup 12/C yield estimates of CO/sub 2/ gas exchange rates and net organic carbon production rates. Between 24 June and 13 August, the calculated CO/sub 2/ gas invasion rate of 0.80 x 10/sup 6/ mol C d/sup -1/ is nearly equal to the river DIC inflow rate. The calculated epilimnetic net organic carbon production rate is 0.68 x 10/sup 6/ mol C d/sup -1/, about 20-30% of primary productivity estimated from /sup 14/C-fixation experiments and ETS-derived respiration rates. Metalimnetic and hypolimnetic DIC increase rates and porewater DIC gradients in hypolimnetic sediments indicate that remineralization of particulate organic carbon (POC) previously deposited in the sediments is a major (0.5 x 10/sup 6/ mol C d/sup -1/) DIC source to the lake during summer. For the whole year, summertime CO/sub 2/ gas invasion balances wintertime CO/sub 2/ gas evasion and DIC and POC outflow balance DIC and POC inflow rates, implying no net carbon burial in the sediments during 1980. This contrasts with the measured long term sedimentation-rate-derived carbon burial rate of 0.8 x 10/sup 6/ mol C d/sup -1/. Year-to-year variability in summertime primary production rates largely determines net gains or losses of carbon via CO/sub 2/ gas exchange and sedimentation.

• Research Organization: Univ. of Washington, Seattle
• OSTI ID: 5221497
• Journal Information: Limnol. Oceanogr.; (United States), Vol. 31:3
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CARBON 12
ISOTOPE RATIO
CARBON 13
LAKES
CARBON CYCLE
CARBON DIOXIDE
LIMNOLOGY
MONTHLY VARIATIONS
SEDIMENTS
WASHINGTON
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON OXIDES
CHALCOGENIDES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FEDERAL REGION X
ISOTOPES
LIGHT NUCLEI
NORTH AMERICA
NUCLEI
OXIDES
OXYGEN COMPOUNDS
STABLE ISOTOPES
SURFACE WATERS
USA
VARIATIONS
520101* - Environment
Aquatic- Basic Studies- Radiometric Techniques- (-1989)