Emergence of Chironomidae (Diptera) in Fertilized and Natural Lakes at Saqvaqjuac, N.W.T.

1988 ◽  
Vol 45 (4) ◽  
pp. 731-737 ◽  
Author(s):  
Harold E. Welch ◽  
John K. Jorgenson ◽  
Martin F. Curtis
Keyword(s):  
Primary Production ◽  
Phytoplankton Production ◽  
Experimental Lakes Area ◽  
Natural Lakes ◽  
Before And After ◽  
Mean Size ◽  
Apparent Reason ◽  
Total Primary Production ◽  
Latitudinal Range ◽  
Lake Fertilization

Chironomid emergence was quantified in four small lakes at Saqvaqjuac, N.W.T. (63°39′N), before and after lake fertilization. Emerging biomass responded immediately to increased phytoplankton production, reaching equilibrium the following year. Emergence from the reference lake was extremely variable, for no apparent reason. The emergence – phytoplankton production relationships found by Davies for the Experimental Lakes Area (~49°N) were generally valid for Saqvaqjuac lakes and Char Lake (74°42′), except that (1) biomass was better correlated than numbers because of increased mean size with increasing latitude and (2) total primary production was a better predictor than phytoplankton production alone because benthic photosynthesis increases with increasing latitude. Chironomid production seems to be a predictable function of total primary production throughout the latitudinal range of the small Canadian lakes examined.

Phytoplankton, Nutrients, and Primary Production in Fertilized and Natural Lakes at Saqvaqjuac, N.W.T.

1989 ◽  
Vol 46 (1) ◽  
pp. 90-107 ◽  
Author(s):  
Harold E. Welch ◽  
John A. Legauit ◽  
Hedy J. Kling
Keyword(s):  
Primary Production ◽  
Light Flux ◽  
Phytoplankton Production ◽  
Small Lakes ◽  
Experimental Lakes Area ◽  
Natural Lakes ◽  
Northwestern Ontario ◽  
North Temperate Lakes ◽  
P Addition ◽  
Very High

Whole-lake phosphorus (P) and nitrogen (N) addition experiments at Saqvaqjuac, N.W.T. (63°N in the central Canadian arctic), showed that the lakes were P limited but required both P and N for increased production. Photosynthetic response to 0.1 g P and 1.0 g N∙m−2∙yr−1 was immediate (15→30 g C∙m−2∙yr−1), with simultaneous increases in protozoa, while oligotrophic chrysophyte assemblages gave way to volvocalean greens. Cyanophytes were not important during P-only or P and N additions or in oligotrophic lakes, but formed permanent blooms in several naturally mesotrophic lakes near sea level. Retention of P was naturally low, but high during P addition. Silicon (Si) retention was always very high. Chlorophyll: P ratios were similar to those of subarctic and north-temperate lakes. Saturation light intensity (Ik) tracked surface light flux with a 2- to 3-wk delay, averaging 15 E∙m−2∙s−1 in winter and peaking at 140 E∙m−2∙s−1 in July. Comparison of our data with those for lakes in the Experimental Lakes Area (northwestern Ontario, 50°N) and Char Lake (75°N) shows that with increasing latitude, in small lakes, (a) phytoplankton production decreases, (b) phytoplankton production per unit light decreases less sharply, and (c) the proportion of primary production occurring beneath ice cover increases.

Primary Production and Phytoplankton in the Experimental Lakes Area, Northwestern Ontario, and other Low-Carbonate Waters, and a Liquid Scintillation Method for Determining 14C Activity in Photosynthesis

1971 ◽  
Vol 28 (2) ◽  
pp. 189-201 ◽  
Author(s):  
D. W. Schindler ◽  
S. K. Holmgren
Keyword(s):  
Primary Production ◽  
Liquid Scintillation ◽  
Species Abundance ◽  
Euphotic Zone ◽  
Phytoplankton Production ◽  
Phytoplankton Species ◽  
Experimental Lakes Area ◽  
Phytoplankton Species Composition ◽  
Northwestern Ontario ◽  
Filtration Error

A modified 14C method is described for measuring phytoplankton production in low-carbonate waters. The procedure includes the use of the Arthur and Rigler (Limnol. Oceanogr. 12: 121–124, 1967) technique for determining filtration error, liquid scintillation counting for determining the radioactivity of membrane filters and stock 14C solutions, and gas chromatography for measuring total CO2.Primary production, chlorophyll a, and total CO2 were measured for two dates in midsummer from each of several lakes in the Experimental Lakes Area (ELA), ranging from 1 to 1000 ha in area and from 2 to 117 m in maximum depth. Phytoplankton species abundance and biomass were determined for the same dates. Production ranged from 0.02 to 2.12 gC/m3∙day and from 0.179 to 1.103 g C/m2∙day. Chlorophyll ranged from 0.4 to 44 mg/m3 and from 5 to 98 mg/m2 in the euphotic zone. The corresponding ranges for live phytoplankton biomass were 120–5400 mg/m3 and 2100–13,400 mg/m2. Chrysophyceae dominated the phytoplankton of most of the lakes.A system for classifying the lakes in terms of phytoplankton species composition and production–depth curves is developed.

Methyl mercury in aquatic insects from an experimental reservoir

1998 ◽  
Vol 55 (9) ◽  
pp. 2036-2047 ◽  
Author(s):  
B D Hall ◽  
D M Rosenberg ◽  
A P Wiens
Keyword(s):  
Aquatic Insects ◽  
Methyl Mercury ◽  
Fold Increase ◽  
Fish Tissue ◽  
Functional Feeding Groups ◽  
Experimental Lakes Area ◽  
Major Pathway ◽  
Natural Lakes ◽  
Northwestern Ontario ◽  
Before And After

Our objective was to study the effects of experimental flooding of a small wetland lake on the methyl mercury (MeHg) concentrations in aquatic insects and to compare MeHg concentrations in insects with those in water and fish from the same system. Insects were collected from the shorelines of the experimental reservoir before and after flooding, an undisturbed wetland lake, and an oligotrophic lake, all in the Experimental Lakes Area in northwestern Ontario. Samples were identified to the lowest possible taxon and categorized into functional feeding groups (FFGs; predators or collector/shredders). The insects were analyzed for MeHg and total Hg using clean techniques. Contamination was not a problem because levels of MeHg in insects were much higher than background concentrations. Odonata, Corixidae, Gerridae, Gyrinidae, and Phryganeidae/Polycentropodidae exhibited increases in MeHg concentrations in response to flooding. When data were grouped into FFGs, increases were observed in predators. There were insufficient numbers of collector/shredders collected to make a definitive conclusion on MeHg increases. Predators exhibited an approximately threefold increase in MeHg concentrations after flooding compared with a 20-fold increase in water concentrations and a four- to five-fold increase in fish concentrations. Trends in MeHg concentrations in aquatic insects from reservoirs and natural lakes in Finland and northern Québec were similar to ours. Evidence of an increase in MeHg concentrations in the lower food web helps explain increases in MeHg concentrations in fish from reservoirs because food is the major pathway of MeHg uptake in fish tissue.

New and regenerated primary production in a productive reservoir ecosystem

2010 ◽  
Vol 67 (2) ◽  
pp. 278-287 ◽  
Author(s):  
Leah M. Domine ◽  
Michael J. Vanni ◽  
William H. Renwick
Keyword(s):  
Primary Production ◽  
Euphotic Zone ◽  
Gizzard Shad ◽  
Phytoplankton Production ◽  
Total Production ◽  
Relative Importance ◽  
Dorosoma Cepedianum ◽  
New Production ◽  
Total Primary Production ◽  
The Difference

The concept of new and regenerated production has been used extensively in marine ecosystems but rarely in freshwaters. We assessed the relative importance of new and regenerated phosphorus (P) in sustaining phytoplankton production in Acton Lake, a eutrophic reservoir located in southwestern Ohio, USA. Sources of nutrients to the euphotic zone, including watershed loading, fluxes from sediments, and excretion by sediment-feeding fish (gizzard shad, Dorosoma cepedianum ), were considered sources of new P input that support new primary production and were quantified over the course of a growing season. Regenerated production was estimated by the difference between new and total primary production. New production represented 32%–53% of total primary production, whereas regenerated production represented 47%–68% of total primary production. P excretion by gizzard shad supplied 45%–74% of new P and 24% of P required for total production. In summary, fluxes of P from the watershed and those from sediment-feeding fish need to be considered in strategies to reduce eutrophication in reservoir ecosystems.

Response of Amphipoda and Trichoptera to Lake Fertilization in the Canadian Arctic

1992 ◽  
Vol 49 (11) ◽  
pp. 2354-2362 ◽  
Author(s):  
John K. Jorgenson ◽  
Harold E. Welch ◽  
Martin F. Curtis
Keyword(s):  
Life Cycle ◽  
Primary Production ◽  
Northwest Territories ◽  
Canadian Arctic ◽  
Phytoplankton Production ◽  
Natural Conditions ◽  
Gammarus Lacustris ◽  
The Third ◽  
Biomass Ratio ◽  
Lake Fertilization

Small oligotrophic lakes at Saqvaqjuac, Northwest Territories, were fertilized with phosphorus and nitrogen after 2 yr of study and the response of macroinvertebrates to increased primary production was followed for 3 yr. The amphipod Gammarus lacustris lacustris (G. O. Sars) had a 2-yr life cycle, with three cohorts present in August. Biomass under natural conditions was approximately 0.1–0.2 g dry wt∙m−2. Gammarus responded immediately to a doubling of phytoplankton production with increased survival of young-of-year. Gammarus biomass increased steadily to 0.9 g dry wt∙m−2 and had not stabilized after 3 yr of fertilization. Trichoptera were represented by three species, with Grensia praeterita composing the bulk of the biomass, followed by Apatania zonella and an uncommon Hesperophylax species. Trichoptera biomass ranged from 0.04 to 0.3 g dry wt∙m−2 before fertilization. Response to increased primary production was slow, beginning in year 2 of fertilization. Trichoptera biomass had doubled by the third year of fertilization but was probably several years from equilibrium. Application of benthos models, in addition to the data, suggested that the production to biomass ratio was between 1 and 2, averaging 1.5.

Importance of Picoplankton in Lake Superior

1986 ◽  
Vol 43 (1) ◽  
pp. 235-240 ◽  
Author(s):  
Gary L. Fahnenstiel ◽  
Linda Sicko-Goad ◽  
Donald Scavia ◽  
Eugene F. Stoermer
Keyword(s):  
Primary Production ◽  
Lake Superior ◽  
Size Class ◽  
Eukaryotic Cells ◽  
Size Fractionation ◽  
Mean Size ◽  
Total Primary Production ◽  
Chroococcoid Cyanobacteria ◽  
Pass Through ◽  
Track Autoradiography

In Lake Superior, approximately 50% of total primary production is attributable to phytoplankton that pass through a 3-μm screen. The <3-μm size class is dominated by eukaryotic flagellates, nonmotile eukaryotic cells (1 μm), and chroococcoid cyanobacteria. Approximately 20% of total primary production is attributable to orange autofluorescent chroococcoid cyanobacteria (mean size = 0.7 μm) as determined by size fractionation and track autoradiography. These small prokaryotes exhibited abundances of 42 000 and 56 000 cells∙ml−1, maximum photosynthetic rates of 7 and 6 fg∙cell−1∙h−1, and growth rates of 1.5 and 0.8∙d−1 in the epilimnion and hypolimnion, respectively. A significant portion of this picoplankton (<1 μm) production may be consumed by heterotrophic protozoans in a "microbial loop."

scholarly journals Importance of extracellular organic carbon production in the total primary production by tidal-flat diatoms in comparison to phytoplankton

1999 ◽  
Vol 190 ◽  
pp. 289-295 ◽  
Author(s):  
N Goto ◽  
T Kawamura ◽  
O Mitamura ◽  
H Terai
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Tidal Flat ◽  
Carbon Production ◽  
Total Primary Production

Primary Productivity of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion

1984 ◽  
Vol 41 (4) ◽  
pp. 591-604 ◽  
Author(s):  
R. E. Hecky ◽  
S. J. Guildford
Keyword(s):  
Light Intensity ◽  
Primary Production ◽  
Water Column ◽  
Primary Productivity ◽  
Phosphorus Deficiency ◽  
Light Environment ◽  
Phytoplankton Production ◽  
Light Penetration ◽  
The Mean ◽  
Chlorophyll Concentrations

The primary productivity of seven regions of Southern Indian Lake and neighboring Wood Lake was measured during open-water seasons from 1974 to 1978. The lake had regional differences in chlorophyll concentrations and daily rates of integral primary production in 1974 and 1975 prior to impoundment of the lake. Regions receiving Churchill River flow tended to have higher chlorophyll concentrations and production rates than those regions marginal to the flow. Impoundment of the lake resulted in higher efficiencies of primary production in all regions, as indicated by higher light-saturated rates of carbon uptake per unit chlorophyll and by higher initial slopes of the hyperbolic light response relation of the phytoplankton. Many large basins of the lake had light penetration reduced by high concentrations of suspended sediment from eroding shorelines, while other areas had relatively unchanged light penetration. The increased efficiency of carbon fixation per unit chlorophyll resulted in higher rates of integral production in those regions where light penetration was not greatly affected. Daily rates of integral primary production in lake regions where light penetration had decreased markedly were not significantly different after impoundment because efficiencies of light utilization were higher. Comparison of the mean water column light intensities for those turbid regions with the values of Ik (light intensity at the onset of light saturation) for phytoplankton indicated that these turbid regions are now light deficient on average. Phosphorus deficiency, as indicated by alkaline phosphatase activity per unit ATP, which was present before impoundment, has been eliminated as the mean water column light intensity declined below 5 mEinsteins∙m−2∙min−1. The light environment of a new reservoir can be a significant determinant of integral production, and predicting the consequences of impoundment on phytoplankton production requires accurate prediction of the light environment.

Is Total Primary Production in Shallow Coastal Marine Waters Stimulated by Nitrogen Loading?

Oikos ◽  
1996 ◽  
Vol 76 (2) ◽  
pp. 406 ◽  
Author(s):  
Jens Borum ◽  
Kaj Sand-Jensen
Keyword(s):  
Primary Production ◽  
Nitrogen Loading ◽  
Marine Waters ◽  
Coastal Marine ◽  
Total Primary Production

Relationships of Fish Yield to Lake Phytoplankton Standing Crop, Production, and Morphoedaphic Factors

1977 ◽  
Vol 34 (12) ◽  
pp. 2271-2279 ◽  
Author(s):  
Ray T. Oglesby
Keyword(s):  
Primary Production ◽  
Standing Crop ◽  
Crop Production ◽  
Fishery Management ◽  
Cold Water ◽  
Phytoplankton Production ◽  
Fish Yield ◽  
Morphoedaphic Index ◽  
Intensively Managed ◽  
Predicted Values

Fish yield is related to annual primary production, summer phytoplankton standing crop, and the morphoedaphic index for lakes representing a wide variety of typologies by a series of models in the form of log-log regressions. Tentative boundary conditions are established by which lakes inappropriate to the models can be excluded. Confidence intervals for predicted values about the mean are given for the fish yield–phytoplankton standing crop regression. From this relation, potential yields for the lakes studied are reduced from a range of 10,000 to one of 25-fold. Efficiencies with which carbon is transferred from primary production to fish yield vary by 2 to 3 orders of magnitude and are highest for small, intensively managed ponds and lowest for large, deep, cold-water lakes. Models based upon fish yield as a function of phytoplankton production or standing crop are inherently more accurate and subject to fewer exceptions than are those related to morphoedaphic factors. The former appear to be capable of substantial refinement but even in their present state might be employed to make useful predictions for groups of lakes. A suggested supplement to existing approaches in fishery management involves the following sequence: (1) use of expectation-variability diagrams to obtain an overview of the problem, (2) selection of an appropriate model or models to predict yield, (3) prediction of a range of yields, and (4) implementation of regulations proved successful for other lakes in the same yield category. Key words: fish, lakes, phytoplankton, morphoedaphic index, fishery management

Sign in / Sign up

Export Citation Format

Share Document