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Lake-specific responses to elevated atmospheric nitrogen deposition in the Colorado Rocky Mountains, U.S.A.

Hydrobiologia

By:
, , ,
DOI: 10.1023/B:HYDR.0000008636.13361.47

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Abstract

We explored variability among subalpine lakes sharing very similar climate and atmospheric conditions, but differing in watershed characteristics, hydrology, and food web structure. Special attention was given to nitrogen (N) dynamics because the study area receives some of the highest levels of atmospheric N deposition in the Rocky Mountains. We asked if the effect of regional N deposition would be manifested uniformly among neighboring lakes both in terms of ambient conditions and responses to greater nutrient inputs. Catchment vegetation appeared to be the main determinant of ambient nitrate (NO3), phosphate (PO4), and dissolved organic carbon (DOC) concentrations, although in-lake differences in recycling produced variable and contrasting NH4 levels. Phytoplankton chlorophyll a temporarily responded to early season NO3 peaks in the lakes with rocky watersheds, but chlorophyll means over the ice-free season were remarkably similar among lakes despite differences in both nutrient supply and zooplankton grazing. In most cases, phosphorus was limiting to phytoplankton growth, although the importance of N deficiencies was greater in lakes with forested watersheds and fringing wetlands.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Lake-specific responses to elevated atmospheric nitrogen deposition in the Colorado Rocky Mountains, U.S.A.
Series title:
Hydrobiologia
DOI:
10.1023/B:HYDR.0000008636.13361.47
Volume
510
Year Published:
2003
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Hydrobiologia
First page:
103
Last page:
114
Number of Pages:
12