Underwater light penetration, phytoplankton biomass and photosynthetic activity in Lake Xolotlán (Managua)

R. Erikson; E. Hooker; M. Meija

doi:10.1007/bf02291245

Incident Solar Irradiance and Underwater Light Penetration as Factors Controlling the Chlorophyll A Content of a Shallow Equatorial Lake (Lake George, Uganda)

Journal of Ecology ◽

10.2307/2259001 ◽

1974 ◽

Vol 62 (2) ◽

pp. 593 ◽

Cited By ~ 60

Author(s):

G. G. Ganf

Keyword(s):

Chlorophyll A ◽

Solar Irradiance ◽

Light Penetration ◽

Underwater Light ◽

Chlorophyll A Content ◽

Lake George

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MODEL ESTIMATIONS OF CHLOROPHYLL SHARE IN PHYTOPLANKTON

Informatika i sistemy upravleniya ◽

10.22250/isu.2021.67.19-30 ◽

2021 ◽

pp. 19-30

Author(s):

A.I. Abakumov ◽

◽

S.Ya. Pak ◽

Keyword(s):

Dynamic Model ◽

Environmental Conditions ◽

Phytoplankton Biomass ◽

Photosynthetic Activity ◽

Biomass Growth ◽

Environmental Situation

The article proposes and examines a dynamic model of phytoplankton biomass. The amount of chlo-rophyll content in phytoplankton changes in response to environmental situation. The model takes into account the dependence of biomass growth on environmental conditions, as well as the parameters phytoplankton photosynthetic activity.

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Nutrient and gilvin levels in waters of coastal-plain wetlands in an agricultural area of Western Australia

Marine and Freshwater Research ◽

10.1071/mf9880685 ◽

1988 ◽

Vol 39 (5) ◽

pp. 685 ◽

Cited By ~ 18

Author(s):

TJ Wrigley ◽

JM Chambers ◽

AJ McComb

Keyword(s):

Coastal Plain ◽

Phytoplankton Biomass ◽

Particulate Material ◽

Agricultural Activity ◽

Estuarine System ◽

Light Penetration ◽

Phytoplankton Blooms ◽

Consequent Reduction ◽

Coastal Plain Wetlands ◽

High Concentrations

The Peel-Harvey catchment lies on a sandy coastal plain, largely cleared for agriculture, and drains into a eutrophic estuarine system. Sixty-eight wetlands in the catchment had total phosphorus concentrations of 0.4-7.8 mg I-1, the high values being atrributed to agricultural activity. Conductivity was 150-8770 �S cm-1, pH 4.1-9.3. Waters contained high concentrations of gilvin, up to 262 g440 m-1 with a mean ratio of 6.2. Particulate material contributed little to light absorption at lower wavelengths (400-450 nm) but governed absorbance at 600-700 nm. Wetlands with the largest concen- trations of gilvin were located in the grey Bassendean sands, leachates from which had gilvin levels up to 748 g440 m-1. NO phytoplankton blooms were observed, and it is suggested that high gilvin levels and the consequent reduction in light penetration are important in maintaining low phytoplankton biomass in these lakes.

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589 Summer Pruning Effects on Leaf and Whole Canopy Gas Exchange in Apple Trees

HortScience ◽

10.21273/hortsci.34.3.548c ◽

1999 ◽

Vol 34 (3) ◽

pp. 548C-548

Author(s):

Kuo-Tan Li ◽

Alan N. Lakso

Keyword(s):

Photosynthetic Activity ◽

Fruit Size ◽

Light Interception ◽

Light Penetration ◽

Apple Trees ◽

Carbon Supply ◽

Shade Leaves ◽

Reduced Light ◽

Canopy Light Interception

Summer pruning is primarily used in apples to increase the light penetration into inner canopy to improve fruit color. However, summer pruning may reduce fruit size. We hypothesize that removing healthy exterior shoots reduces the whole-tree carbon supply in relation to pruning severity. If the crop load (i.e., demand) is high, fruit size and quality will be reduced. The effects of summer pruning on photosynthetic activity and recovery of shaded leaves after re-exposure were monitored on a range of exposures in canopies of `Empire' apple trees. The photosynthetic ability of leaves was positively related to its prepruning exposure. There was little recovery of photosynthetic activity of shade leaves until late growing season, indicating the re-exposure of shade leaves after summer pruning cannot replace the role of exterior leaves removed by pruning. Whole canopy net CO2 exchange (NCER) was measured on `Empire'/M9 trees with a commercial range of pruning severity. Reductions in NCER were approximately proportional to pruning severity and % leaf area removed and were as great as 60% in the most severe pruning. Canopy light interception decreased slightly. The effects on canopy NCER thus appeared to be primarily related to reduced photosynthetic efficiency and secondarily to reduced light interception.

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Depression of Primary Production by Humic Matter and Suspended Sediment in Limnocorral Experiments at Southern Indian Lake, Northern Manitoba

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-169 ◽

1987 ◽

Vol 44 (8) ◽

pp. 1408-1417 ◽

Cited By ~ 39

Author(s):

S. J. Guildford ◽

F. P. Healey ◽

R. E. Hecky

Keyword(s):

Primary Productivity ◽

Phytoplankton Biomass ◽

Phosphorus Deficiency ◽

Available Phosphorus ◽

Soluble Nitrogen ◽

Light Penetration ◽

Nitrogen And Phosphorus ◽

Humic Material ◽

Enrichment Experiments ◽

Nitrogen And Phosphorus Enrichment

Eroding and flooded shoreline materials were added to a series of limnocorrals in Southern Indian Lake (northern Manitoba) to simulate their effects on the phytoplankton following impoundment of the lake. Inorganic clays depressed primary productivity and phytoplankton biomass but relieved phosphorus deficiency. These effects appeared to be primarily due to reduction of light penetration; release of available phosphorus was small. Organic moss–peat material initially increased and then lowered primary productivity and biomass, while phosphorus deficiency was lowered. The initial stimulation could be traced to the release of soluble nitrogen and phosphorus. Enrichment experiments indicated that the depression was due to the binding of iron or some other metal by dissolved humic material. Responses of phytoplankton in the lake could be understood as a composite of responses seen in the limnocorrals to the two eroding shoreline materials.

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