[Energy Flow in Arctic Aquatic Ecosystems] Page: 12 of 19
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
the surface sediments analyzed thus far, but this is not
unexpected. There appeared to be no major inputs of nacrophytic
plants into the lakes from which these samples were taken, and
algal inputs were probably similarly small since Alexander et al.
(1980) found that algal biomass made up less than one percent of
sediment carbon in the tundra ponds at Barrow. We plan to make
radiocarbon age determinations of the basal peat of shoreline banks
and surface sediments of each lake/pond from which biota are
collected.
IV. The Importance of Peat in Arctic Aquatic Ecosystem Energetics
The role of peat carbon supported energetics will be assessed
by determining the rates of peat oxidation and aerobic and
anaerobic respiration in lakes/ponds during the ice and ice-free
seasons.
When ice is present the exchange of gases between the water
and atmosphere essentially ceases, such that continued aquatic
respiration causes the accumulation of dissolved inorganic carbon
(DIC) and the depletion of dissolved oxygen (DO) in the under-ice
water. The rate of accumulation of DIC of metabolic origin (i.e.,
corrected for carbonate mineral dissolution) is then equal to the
rate of total carbon metabolism, and the rate of exhaustion of DO
is equal to the rate of aerobic metabolism. The difference between
these rates is the rate of anaerobic metabolism.
Oxidative processes cause changes not only in the
concentration of DIC, but also inits carbon isotope composition
(14C, 13C, and 12C). These isotope changes can be used to provide
another estimate of the rates of aerobic and anaerobic respiration,
and an estimate of the rate of peat oxidation. The changes in the
13C/12C ratios of the DIC are used to determine the rates of oxic
and anoxic metabolic processes (Deevey and Stuiver, 1964). This is
possible because the C02 produced anaerobically is enriched in 13C
relative to that produced aerobically (613C -5% and -30%,
respectively). The proportion of C02 derived from each process is
calculated with a mixing equation and the 613C values of the
aerobic and anaerobic C02' and the DIC of the lake water.
-12-
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Schell, D. M. [Energy Flow in Arctic Aquatic Ecosystems], report, December 31, 1985; Fairbanks, Alaska. (https://digital.library.unt.edu/ark:/67531/metadc1310787/m1/12/?rotate=270: accessed July 17, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.