Effects of Lake Size on Phytoplankton Photosynthesis

1992 ◽  
Vol 49 (12) ◽  
pp. 2445-2459 ◽  
Author(s):  
E. J. Fee ◽  
J. A. Shearer ◽  
E. R. DeBruyn ◽  
E. U. Schindler
Keyword(s):  
Interannual Variation ◽  
Additional Data ◽  
Climatic Warming ◽  
Lake Surface ◽  
Total Rainfall ◽  
Large Lakes ◽  
Growing Seasons ◽  
Shield Lakes ◽  
Lake Size ◽  
Phytoplankton Photosynthesis

Phytoplankton photosynthesis (PP) was measured for 6 yr in seven remote Canadian Shield lakes that stratify fully during the summer and have water renewal times > 5 yr but vary from 29 to 34 700 ha; Lakes Nipigon and Superior were also studied in two years. Chlorophyll and PP at optimum light were low in the smallest and largest lakes and increased systematically to values nearly five times higher in midsized lakes (~103 ha). Daily PP per square metre of lake surface and annual PP per cubic metre of the mixed layer also varied in this manner, but annual PP per square metre was high in large lakes (despite their low density rates) because of their long growing seasons. Additional data are needed to determine whether the photosynthesis maximum in midsized lakes is inherently size related or an accidental statistical result. Intraannually, chlorophyll-based photosynthesis parameters ([Formula: see text], αB) were similar in all lake sizes, but interannually they varied by two to three times; this interannual variation was significantly correlated with total rainfall during May and June. Implications for extrapolating experimental results from small to large lakes, selecting lakes for interregional comparison studies and predicting how climatic warming would affect phytoplankton photosynthesis are discussed.

Effects of Lake Size on Phytoplankton Nutrient Status

1994 ◽  
Vol 51 (12) ◽  
pp. 2769-2783 ◽  
Author(s):  
S. J. Guildford ◽  
L. L. Hendzel ◽  
H. J. Kling ◽  
E. J. Fee ◽  
G. G. C. Robinson ◽  
...  
Keyword(s):  
Nutrient Status ◽  
Canadian Shield ◽  
Small Lakes ◽  
Large Lakes ◽  
P Deficiency ◽  
Water Renewal ◽  
Mixed Layers ◽  
Shield Lakes ◽  
Lake Size ◽  
Total P

Phytoplankton nutrient status measurements (C/P, C/N, C/chlorophyll, N/P, alkaline phosphatase activity, and N debt) were measured for 6 yr in seven remote Canadian Shield lakes. Lakes Nipigon and Superior were also studied for 2 yr. These lakes varied in surface area from 29 to 8.223 × 10 ha, they all stratified fully during the summer and had water renewal times > 5 yr. All lakes were severely P deficient; however, the large lakes (> 2000 ha) were consistently less P deficient than small lakes. A growth-rate indicator (photosynthesis normalized to particulate C) agreed with nutrient status indicators, in that small lakes had lower rates than large lakes. Total P was a good predictor of chlorophyll, but factors related to lake size (temperature and mixed depth) were equally good or better predictors of nutrient status. Decreasing mean water column light intensity could not explain the lower P deficiency of large lakes. The deeper, more energetic mixed layers in large lakes apparently cause P to be recycled more efficiently. Extrapolation of observations or experimental results from small to large lakes requires recognition that phytoplankton in large lakes are less nutrient deficient and may have higher growth rates.

Effects of Lake Size on Nutrient Availability in the Mixed Layer during Summer Stratification

1994 ◽  
Vol 51 (12) ◽  
pp. 2756-2768 ◽  
Author(s):  
E. J. Fee ◽  
R. E. Hecky ◽  
G. W. Regehr ◽  
L. L. Hendzel ◽  
P. Wilkinson
Keyword(s):  
Mixed Layer ◽  
Nutrient Recycling ◽  
Nutrient Regeneration ◽  
Small Lakes ◽  
Large Lakes ◽  
Total N ◽  
Northwestern Ontario ◽  
Mixed Layers ◽  
Shield Lakes ◽  
Lake Size

Fluxes to the summer mixed layer of N, Si, and P were estimated in a size series of northwestern Ontario Canadian Shield lakes. Increasing turbulence caused upward fluxes through the thermocline to increase with lake size for nutrients that increased in concentration below the thermocline (soluble reactive Si, total inorganic N, and NO3−; but not total N or any form of P). Precipitation and terrestrial runoff were equally important sources of N and P in all but very small lakes (< 100 ha), where precipitation supplied much more than runoff. Runoff was the only important source of Si, except in very large lakes (> 100 000 ha) where mixing through the thermocline was important. N2-fixation was unimportant except in intermediate-sized fakes (700–2000 ha). Si fluxes nearly equaled phytoplankton requirements, but N and P were below requirements, and recycling within the mixed layer must be the most important source of these nutrients. N and P deficits increased progressively with lake size, implying that the efficiency of nutrient recycling increased with lake size; mixed layers in large lakes are more turbulent and thicker than in small lakes and these processes increase the probability of nutrient regeneration within the mixed layer.

scholarly journals Influence of Environment on Atmospheric Concentrations of Peronospora antirrhini Sporangia in Field-Grown Snapdragon

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1060-1066 ◽  
Author(s):  
J. M. Byrne ◽  
M. K. Hausbeck ◽  
L. E. Sconyers
Keyword(s):  
Average Length ◽  
Pathogen Resistance ◽  
Management Program ◽  
Leaf Wetness ◽  
Environmental Cues ◽  
Total Rainfall ◽  
Growing Seasons ◽  
Positive Correlations ◽  
Total Spore Count ◽  
Atmospheric Concentrations

Hourly concentrations of airborne sporangia of Peronospora antirrhini at a commercial snapdragon farm were investigated over three growing seasons to determine the influence of the environment on their occurrence and concentration. Hourly concentrations of sporangia of P. antirrhini were estimated using a Burkard volumetric spore sampler. Atmospheric sporangial concentrations followed a diurnal pattern and were greatest during 0500 to 1200 h. Minimum daily temperatures <10.0°C appeared to have a moderate limiting effect on atmospheric sporangial concentrations, whereas temperatures <6.0°C had more severe limiting effects. Maximum daily temperatures ≥30.0°C limited concentrations of atmospheric sporangia. Long dew periods (≥6 h) were associated with relatively large sporangia releases. On 69 days (1999 to 2001), the total number of sporangia trapped was >100/m3/day, and the average length of leaf wetness duration prior to these releases was 11 h. Consecutive days with short leaf wetness periods were associated with low atmospheric sporangial concentrations. Significant positive correlations (P = 0.0502 and P = 0.0174) were found between total rainfall and total spore count for both research plots in 2000. Information gained from this study will contribute to the development of a disease management program that utilizes environmental cues to prompt fungicide applications, thus increasing the efficiency of fungicide programs and delaying the development of pathogen resistance.

scholarly journals The size-distribution of Earth’s lakes

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
B. B. Cael ◽  
D. A. Seekell
Keyword(s):  
Power Law ◽  
Theoretical Explanation ◽  
Lake Area ◽  
Power Law Distribution ◽  
Small Lakes ◽  
Large Lakes ◽  
Lake Ecology ◽  
Empirical Distributions ◽  
Theoretical Predictions ◽  
Lake Size

Abstract Globally, there are millions of small lakes, but a small number of large lakes. Most key ecosystem patterns and processes scale with lake size, thus this asymmetry between area and abundance is a fundamental constraint on broad-scale patterns in lake ecology. Nonetheless, descriptions of lake size-distributions are scarce and empirical distributions are rarely evaluated relative to theoretical predictions. Here we develop expectations for Earth’s lake area-distribution based on percolation theory and evaluate these expectations with data from a global lake census. Lake surface areas ≥0.46 km2 are power-law distributed with a tail exponent (τ = 2.14) and fractal dimension (d = 1.4), similar to theoretical expectations (τ = 2.05; d = 4/3). Lakes <0.46 km2 are not power-law distributed. An independently developed regional lake census exhibits a similar transition and consistency with theoretical predictions. Small lakes deviate from the power-law distribution because smaller lakes are more susceptible to dynamical change and topographic behavior at sub-kilometer scales is not self-similar. Our results provide a robust characterization and theoretical explanation for the lake size-abundance relationship, and form a fundamental basis for understanding and predicting patterns in lake ecology at broad scales.

scholarly journals Thinning and Diametric Fruit Growth Response of Apple Trees Treated with Benzyladenine and GA4+7 (Accel®), Carbaryl, and NAA

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 787E-787
Author(s):  
John A. Cline ◽  
Mary Bom ◽  
Donald C. Elfving
Keyword(s):  
Growth Response ◽  
Additional Data ◽  
Fruit Size ◽  
Fruit Growth ◽  
Sharp Decline ◽  
Fruit Thinning ◽  
Growing Seasons ◽  
Fruit Maturity ◽  
Cluster Rate ◽  
Number Of Seeds

A series of seven fruit thinning experiments with benzyladenine (BA), benzyladenine and GA4+7 (10:1 BA:GA4+7, Accel), carbaryl (CB), and NAA were conducted at the Horticultural Experiment Station, Simcoe, during the 1993 and 1994 growing seasons. In 1993, BA and Accel at 0, 100, 200, and 300 mg of BA/liter were applied to mature `Redspur Delicious'/M.26 and `Empire'/M.26 trees when fruit were ≈10 mm in diameter. In one set of experiments in 1994, Accel was applied at 0, 25, 50, 100, 150, and 200 mg of BA/liter to mature `McIntosh'/M.26 and `Empire'/M.7 trees. In a second set of experiments in 1994, Accel was applied at 0, 50, and 100 mg of BA/liter to mature `Idared'/M.26, `Empire'/M.26, and `Marshall McIntosh'/Mark trees when fruit were ≈10 mm in diameter. Additional treatments included bloom sprays of Accel at 50 mg of BA/liter, and sprays of BA at 50 mg a.i/liter, NAA at 10 mg a.i./liter, CB at 1000 mg a.i./liter, and a “low” (two fruit remaining/flower cluster) and `”high” (one fruit remaining/flower cluster) rate of hand thinning. In all experiments, thinning response to BA and Accel increased with concentration. Concentrations below 50, 100, and 300 mg BA/liter were generally ineffective for thinning `Empire', `Idared', and `McIntosh', and `Delicious', respectively. Fruit size of `Idared' and `Empire' was increased at rates of 50 mg BA/liter, whereas rates of 100 mg BA/liter were needed to increase fruit size of `McIntosh'. Accel applied to `Empire' at 150 mg BA/liter decreased the number of seeds per fruit and increased fruit length:diameter (L:D) ratios. Concentrations of Accel exceeding 100 mg BA/liter in `Red Delicious' decreased the number of seeds per fruit, while having little effect on fruit L:D ratios even though lower concentrations increased fruit L:D ratios. Diametric fruit growth measurements in 1994 indicated a temporary, but sharp, decline in growth rate immediately following treatment imposition for trees that responded positively to thinning. Additional data describing treatment effects on fruit size distribution, vegetative growth, and fruit maturity will be presented and discussed in relation to crop load.

scholarly journals Improved Orchard Establishment of Asimina triloba Seedlings on Acid Soils Supplemented with Calcium Sulfate

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 475A-475
Author(s):  
G.A. Picchioni ◽  
C.J. Graham
Keyword(s):  
Calcium Sulfate ◽  
Dry Matter ◽  
Additional Data ◽  
Acid Soils ◽  
Deciduous Tree ◽  
Dry Matter Accumulation ◽  
Cross Sectional ◽  
Growing Seasons ◽  
Asimina Triloba ◽  
Orchard Soil

Asimina triloba (L.) Dunal (pawpaw), a deciduous tree indigenous to the eastern U.S., is being considered as a potential new fruit crop. The difficulty in establishing transplanted pawpaw seedlings has been identified as an important research need for successful cultivation of this species. We have addressed the possible benefits of soil-applied CaSO4 in establishing pawpaw seedlings on acidic, low-Ca orchard soil. Two-year-old seedling rootstocks were planted at a spacing of 1.5 m (within rows) × 5.5 m (between rows), and trickle-irrigated (with N, P, and K) for two growing seasons. Before planting, CaSO4 was applied at rates of 0, 11, and 22 t/ha and incorporated to a depth of 15 cm. Seedling trunk cross-sectional area (TCA) growth increased with increasing CaSO4 application. After the first season, increases in TCA averaged 27% and 44% greater with CaSO4 treatments (11 and 22 t/ha, respectively), as compared to the 0 t/ha treatment. This effect was accentuated by the end of the second season. Average qualitative ratings (based on seedling vigor and appearance) were also improved with CaSO4 treatment. These findings indicate that establishment of pawpaw seedling rootstocks may be improved with Ca fertilization in orchards of low-Ca status. Additional data, including seedling dry matter accumulation, will be presented.

Drivers of walleye recruitment in Minnesota’s large lakes

2020 ◽  
Vol 77 (12) ◽  
pp. 1921-1933
Author(s):  
Andrew E. Honsey ◽  
Zachary S. Feiner ◽  
Gretchen J.A. Hansen
Keyword(s):  
Thermal Conditions ◽  
Predictive Performance ◽  
First Year ◽  
Large Lakes ◽  
Substantial Impact ◽  
Inland Lakes ◽  
Growing Seasons ◽  
Class Strength ◽  
Explained Variance ◽  
First Year Of Life

Fish recruitment is complex and difficult to predict. Data-driven approaches show promise for predicting recruitment and understanding its drivers. We used a random forest model to infer relationships between year-class strength and 17 variables describing potential recruitment drivers across 30+ years of walleye (Sander vitreus) data from Minnesota’s nine largest inland lakes. Our model explained 20% of the variation in year-class strength overall, with predictive performance varying among lakes (–8% to 37% explained variance). Of the variables analyzed, degree-days during the first year of life and first winter severity were the most important for predicting recruitment, with relatively weak year classes predicted to occur with cold first growing seasons and severe first winters. Other thermal variables were secondarily important predictors of year-class strength. Predicted year-class strength was positively related to stock size and stocking and negatively related to the presence of invasive species; however, these variables were less important than thermal variables. Our results indicate that thermal conditions in early life can have a substantial impact on walleye recruitment and highlight the potential for differing recruitment drivers and dynamics among lakes.

Ecology and productivity of Cantharellus cibarius var. roseocanus in two eastern Canadian jack pine stands

Botany ◽  
2011 ◽  
Vol 89 (10) ◽  
pp. 663-675 ◽  
Author(s):  
Caroline Rochon ◽  
David Paré ◽  
Nellia Pélardy ◽  
Damase P. Khasa ◽  
J. André Fortin
Keyword(s):  
Pinus Banksiana ◽  
C:N Ratio ◽  
Mineral Soil ◽  
Stand Density ◽  
Economic Importance ◽  
Site Conditions ◽  
Plant Association ◽  
Total Rainfall ◽  
Growing Seasons ◽  
Positive Correlations

Despite the economic importance of chanterelles, much remains to be known about their habitat requirements. Cantharellus cibarius var. roseocanus Redhead, Norvell & Danell sporocarp productivity was measured during three growing seasons in two Pinus banksiana Lamb. stands of boreal forest. The objective was to determine how the variability in stand, plant association, edaphic, and meteorological conditions was related to sporocarp productivity. DNA of this species was detected in organic and mineral soil horizons. Sporocarp productivity was similar for both stands, but the absence of colonies on trails at one of the sites likely reflects microenvironmental conditions that are unsuitable for chanterelle growth. Under the prevailing site conditions, preferred microhabitats were characterized by high stand density, high C:N ratio, and frequent moss presence. The Solidago puberula Nutt. – Comptonia peregrina (L.) Coulter – Pinus banksiana association, lichen presence, and as much clay and silt content as can possibly be found on this moderately acidic sandy soil favoured the productivity of this chanterelle, whereas ericaceous species presence was negatively correlated with chanterelle productivity. Positive correlations were found between total rainfall 1 week prior to fructification, air temperature 2 weeks prior to fructification, and sporocarp productivity. Results highlight the specific conditions favourable to Cantharellus cibarius var. roseocanus fructifications within these stands.

Blowin’ in the wind: reciprocal airborne carbon fluxes between lakes and land This paper is based on the J.C. Stevenson Memorial Lecture presented at the Canadian Conference for Fisheries Research (CCFFR) in Ottawa, Ontario, 9–11 January 2009.

2011 ◽  
Vol 68 (1) ◽  
pp. 170-182 ◽  
Author(s):  
M. Jake Vander Zanden ◽  
Claudio Gratton
Keyword(s):  
Carbon Flux ◽  
Open Water ◽  
Memorial Lecture ◽  
Published Data ◽  
Insect Emergence ◽  
Large Lakes ◽  
Lake Ecosystems ◽  
Ecosystem Size ◽  
Lake Size

Ecologists are increasingly interested in how disjunct habitats are connected through the cross-habitat movement of matter, prey, nutrients, and detritus and the implications for recipient systems. The study of lake ecosystems has been dominated by the study of pelagic (open-water) production and processes, though there is growing awareness of the role of terrestrial inputs and benthic trophic pathways. Here, we review the phenomena of airborne fluxes to and from lakes. We assemble published data on terrestrial particulate organic carbon (TPOC) deposition to lakes, insect production, and insect emergence and use these data to simulate how airborne lake-to-land and land-to-lake carbon flux is expected to scale with ecosystem size, while taking into account among-lake variability in emergence and TPOC deposition. Emergent insect flux to land increases as a function of lake size, while TPOC deposition to lakes decreases as a function of lake size. TPOC deposition exceeds insect emergence in small lakes, while in large lakes, insect emergence exceeds TPOC deposition. We present a general framework for considering directional fluxes across habitat boundaries. Furthermore, our results highlight the overarching role of ecosystem geometry in determining insect emergence, airborne carbon deposition, and net carbon flux between adjacent ecosystems.

scholarly journals Methane paradox in tropical lakes? Sedimentary fluxes rather than water column production in oxic waters sustain methanotrophy and emissions to the atmosphere

2020 ◽  
Author(s):  
Cédric Morana ◽  
Steven Bouillon ◽  
Vimac Nolla-Ardèvol ◽  
Fleur A. E. Roland ◽  
William Okello ◽  
...  
Keyword(s):  
Surface Waters ◽  
Tropical Lakes ◽  
Large Lakes ◽  
Ch4 Flux ◽  
Ch4 Emissions ◽  
Isotope Tracer ◽  
Ch4 Production ◽  
Elevated Water ◽  
Lake Size ◽  
Sunlight Intensity

Abstract. Despite growing evidence that methane (CH4) formation could also occur in well-oxygenated surface freshwaters, its significance at the ecosystem scale is uncertain. Empirical models based on data gathered at high latitude predict that the contribution of oxic CH4 increases with lake size and should represent the majority of CH4 emissions in large lakes. However, such predictive models could not directly apply to tropical lakes which differ from their temperate counterparts in some fundamental characteristics, such as year-round elevated water temperature. We conducted stable isotope tracer experiments which revealed that oxic CH4 production is closely related to phytoplankton metabolism, and is a common feature in five contrasting African lakes. Nevertheless, methanotrophic activity in surface waters and CH4 emissions to the atmosphere were predominantly fuelled by CH4 generated in sediments and physically transported to the surface. Indeed, measured CH4 bubble dissolution flux and diffusive benthic CH4 flux were several orders of magnitude higher than CH4 production in surface waters. Microbial CH4 consumption dramatically decreased with increasing sunlight intensity, suggesting that the freshwater CH4 paradox might be also partly explained by photo-inhibition of CH4 oxidizers in the illuminated zone. Sunlight appeared as an overlooked but important factor determining the CH4 dynamics in surface waters, directly affecting its production by photoautotrophs and consumption by methanotrophs.

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