Document Detail


Convective gas flow development and the maximum depths achieved by helophyte vegetation in lakes.
MedLine Citation:
PMID:  19491087     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND AIMS: Convective gas flow in helophytes (emergent aquatic plants) is thought to be an important adaptation for the ability to colonize deep water. In this study, the maximum depths achieved by seven helophytes were compared in 17 lakes differing in nutrient enrichment, light attenuation, shoreline exposure and sediment characteristics to establish the importance of convective flow for their ability to form the deepest helophyte vegetation in different environments.
METHODS: Convective gas flow development was compared amongst the seven species, and species were allocated to 'flow absent', 'low flow' and 'high flow' categories. Regression tree analysis and quantile regression analysis were used to determine the roles of flow category, lake water quality, light attenuation and shoreline exposure on maximum helophyte depths.
KEY RESULTS: Two 'flow absent' species were restricted to very shallow water in all lakes and their depths were not affected by any environmental parameters. Three 'low flow' and two 'high flow' species had wide depth ranges, but 'high flow' species formed the deepest vegetation far more frequently than 'low flow' species. The 'low flow' species formed the deepest vegetation most commonly in oligotrophic lakes where oxygen demands in sediments were low, especially on exposed shorelines. The 'high flow' species were almost always those forming the deepest vegetation in eutrophic lakes, with Eleocharis sphacelata predominant when light attenuation was low, and Typha orientalis when light attenuation was high. Depths achieved by all five species with convective flow were limited by shoreline exposure, but T. orientalis was the least exposure-sensitive species.
CONCLUSIONS: Development of convective flow appears to be essential for dominance of helophyte species in >0.5 m depth, especially under eutrophic conditions. Exposure, sediment characteristics and light attenuation frequently constrain them to a shallower depth than their flow capacity permits.
Authors:
Brian K Sorrell; Ian Hawes
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Annals of botany     Volume:  105     ISSN:  1095-8290     ISO Abbreviation:  Ann. Bot.     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2009-12-16     Completed Date:  2010-02-12     Revised Date:  2011-07-19    
Medline Journal Info:
Nlm Unique ID:  0372347     Medline TA:  Ann Bot     Country:  England    
Other Details:
Languages:  eng     Pagination:  165-74     Citation Subset:  IM    
Affiliation:
National Institute of Water and Atmospheric Research, PO Box 8602, Christchurch, New Zealand. brian.sorrell@biology.au.dk
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Convection
Fresh Water
Gases / metabolism*
Geologic Sediments / chemistry
Light
Oxygen / metabolism
Plant Physiological Phenomena
Plants / metabolism*
Regression Analysis
Species Specificity
Chemical
Reg. No./Substance:
0/Gases; 7782-44-7/Oxygen
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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