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Inter-annual, seasonal and spatial variability in nutrient limitation of phytoplankton production in a river impoundment

Hydrobiologia

By:
and
DOI: 10.1023/A:1021388315552

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Abstract

We characterize seasonal and spatial patterns in phytoplankton abundance, production and nutrient limitation in a mesotrophic river impoundment located in the southeastern United States to assess variation arising from inter-annual differences in watershed inputs. Short-term (48 h) in situ nutrient addition experiments were conducted between May and October at three sites located along the longitudinal axis of the lake. Nutrient limitation was detected in 12 of the 18 experiments conducted over 2 years. Phytoplankton responded to additions of phosphorus alone although highest chlorophyll concentrations were observed in enclosures receiving combined (P and N) additions. Growth responses were greatest at downstream sites and in late summer suggesting that those populations experience more severe nutrient limitation. Interannual variation in nutrient limitation and primary production corresponded to differences in the timing of hydrologic inputs. Above average rainfall and discharge in late-summer (July-October) of 1996 coincided with higher in-lake nutrient concentrations, increased production, and minimal nutrient limitation. During the same period in 1995, discharge was lower, nutrient concentrations were lower, and nutrient limitation of phytoplankton production was more pronounced. Our results suggest that nutrient limitation is common in this river impoundment but that modest inter-annual variability in the timing of hydrologic inputs can substantially influence seasonal and spatial patterns.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Inter-annual, seasonal and spatial variability in nutrient limitation of phytoplankton production in a river impoundment
Series title:
Hydrobiologia
DOI:
10.1023/A:1021388315552
Volume
481
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Hydrobiologia
First page:
19
Last page:
31
Number of Pages:
13