Chlorophyll Concentrations in Relation to Environmental Parameters in Different Situations in Shoal Lake (Manitoba-Ontario)

✍ Scribed by Eva Pip

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 951 KB
• Volume: 73
• Category: Article
• ISSN: 1434-2944
• DOI: 10.1002/iroh.19880730405

✦ Synopsis

Seasonal and local chl a fluctuations nere examined at t w o depth ranges in Shoal Lake, a productive Precambrian Shield system. Water residence time in the study area was short), without permanent summer stratification. Chl a fluctuations were significantly correlated with total molybdenum reactive phosphorus (MRP) and total inorganic nitrogen (TIN), but the types of relationships were different for the two nutrients. Chl a was also significantly Fositively correlated withtotal alkalinity and temperature, and inversely correlated with oxygen and light. MRP and dissolved organic matter appeared to be more imFortant for near-bottom chl than for surface chl. Principal component analysis identified 4 major dimensions in which the different locations could be compared in terms of seasonal chl a fluctuations.

1. I n t r o d u c t i o n

Factors which govern seasonal phytoplankton fluctuations i n lakes have only recwitly begun t o be understood within t h e context of t h e ecological hyperspace concept ( e g . HUTCHINSON, 1967). Of the m a n y parameters which appear t o he influential, phosphorus, nitrogen, light a n d temperature have heen identified as iiiajor factors which affect t h e proliferation of algae i n natural water systems (e.g. HUTCHINSON, 1967; ZDANOWSKI, 1982). However m a n y of the available studies deal with a small number of variables integrated for lake systems a s a whole, generally i n t h e context of well-defined suniiiier thermal stratification a n d long residence times of t h e water niass. Comparatively little of t h e information applies t o systems where the latter criteria do not apply, a n d even less is known regarding t h e relative effects of various fattors in different situations within t h e same water body.

The objective of t h e present study was t o examine seasonal a n d local chlorophyll concentrations in relation t o pH, total dissolved solids, total alkalinity, sulphate, total niolyhdenuni reactive phosphorus (MRP), total inorganic nitrogen (TIN), dissolved oxygen, dissolved organic matter (DOM), light a n d temperature i n Shoal Lake, a prodiictive Precaiiibrian Shield lake. This lake, which is the source of drinking water for t h e City of Winnipeg, lacks permanent suninier stratification a n d has a short water residence time. lnorganic rather t h a n total nitrogen a n d phosphorus were considered because t h e former better reflected t h e nutrient fractions available for uptake at a n y given time.