ENVIRONMENTAL-CONTROL OF PHOTOSYNTHATE ALLOCATION IN THE PHYTOPLANKTON OF GEORGIAN BAY (LAKE HURON)

Citation
Ja. Furgal et al., ENVIRONMENTAL-CONTROL OF PHOTOSYNTHATE ALLOCATION IN THE PHYTOPLANKTON OF GEORGIAN BAY (LAKE HURON), Canadian journal of fisheries and aquatic sciences, 55(3), 1998, pp. 726-736
Citations number
52
Categorie Soggetti
Marine & Freshwater Biology",Fisheries
ISSN journal
0706652X
Volume
55
Issue
3
Year of publication
1998
Pages
726 - 736
Database
ISI
SICI code
0706-652X(1998)55:3<726:EOPAIT>2.0.ZU;2-M
Abstract
Allocation of photosynthate by phytoplankton in Georgian Bay was measu red from spring through fall of 1993 to test previous models for envir onmental control of allocation and to assess for the first time the ef fects on allocation of solar ultraviolet radiation. Ultraviolet-B radi ation (UV-B, 280-320 nm) at near-surface levels significantly inhibite d photosynthesis (by up to 82%) under both natural and artificial ligh t. UV-B effects on allocation to protein, polysaccharide, low molecula r weight materials, and total lipids were rarely significant, but the sensitivity of photosynthesis to UV-B increased directly with allocati on to protein. UV-B exposure had more influence on allocation among li pid classes, but the effects were still statistically marginal. Alloca tion to protein and glycolipids varied directly with silicon availabil ity, while allocation to total lipids and glycolipids varied inversely with phosphorus availability. Previously published models for predict ing protein, polysaccharide, and total lipid allocation from temperatu re and daylength were unsuccessful. Lipid classes showed distinctive s easonal patterns and environmental correlates, consistent with differi ng functional roles and (or) taxonomic associations among the major li pid classes. The allocation of photosynthate, and thus the food qualit y and nutrient stoichiometry of the primary producers, appeared to be under complex control that could not be precisely predicted from any s imple combination of environmental variables.