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Chemical characteristics of particulate, colloidal, and dissolved organic material in Loch Vale Watershed, Rocky Mountain National Park

Biogeochemistry

By:
, , , , and
DOI: 10.1023/A:1005783812730

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Abstract

The chemical relationships among particulate and colloidal organic material and dissolved fulvic acid were examined in an alpine and subalpine lake and two streams in Loch Vale Watershed, Rocky Mountain National Park. The alpine lake, Sky Pond, had the lowest dissolved organic carbon (DOC) (0.37 mgC/L), the highest particulate carbon (POC) (0.13 mgC/L), and high algal biomass. The watershed of Sky Pond is primarily talus slope, and DOC and POC may be autochthonous. Both Andrews Creek and Icy Brook gain DOC as they flow through wet sedge meadows. The subalpine lake, The Loch, receives additional organic material from the surrounding forest and had a higher DOC (0.66 mgC/L). Elemental analysis, stable carbon isotopic compositon, and 13C-NMR characterization showed that: 1) particulate material had relatively high inorganic contents and was heterogeneous in compositon, 2) colloidal material was primarily carbohydrate material with a low inorganic content at all sites; and 3) dissolved fulvic acid varied in compositon among sites. The low concentration and carbohydrate-rich character of the colloidal material suggests that this fraction is labile to microbial degradation and may be turning over more rapidly than particulate fractions or dissolved fulvic acid. Fulvic acid from Andrews Creek had the lowest N content and aromaticity, whereas Sky Pond fulvic acid had a higher N content and lower aromaticity than fulvic acid from The Loch. The UV-visible spectra of the fulvic acids demonstrate that variation in characteristics with sources of organic carbon can explain to some extent the observed nonlinear relationship between UV-B extinction coefficients and DOC concentrations in lakes.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Chemical characteristics of particulate, colloidal, and dissolved organic material in Loch Vale Watershed, Rocky Mountain National Park
Series title:
Biogeochemistry
DOI:
10.1023/A:1005783812730
Volume
36
Issue:
1
Year Published:
1997
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Biogeochemistry
First page:
99
Last page:
124
Number of Pages:
26