Phytoplankton Community Responses to Nutrient Addition in Lake 226, Experimental Lakes Area, Northwestern Ontario

1987 ◽  
Vol 44 (S1) ◽  
pp. s35-s46 ◽  
Author(s):  
D. L. Findlay ◽  
S. E. M. Kasian
Keyword(s):  
Species Composition ◽  
Water Exchange ◽  
Phytoplankton Community ◽  
Late Summer ◽  
Nitrogen And Phosphorus ◽  
Experimental Lakes Area ◽  
Carbon And Nitrogen ◽  
Northwestern Ontario ◽  
Average Biomass ◽  
Reference Lakes

Inclusion of phosphorus in fertilizer added to one of two basins of a small lake, between which water exchange was greatly reduced by a vinyl sea-curtain, significantly increased epilimnetic phytoplankton biomass, and altered species composition. Over an 8-yr period, the average biomass of phytoplankton in the basin receiving carbon, nitrogen, and phosphorus (in ratios of 10:5:1) increased 4 to 8 times and the biomass in the basin receiving only carbon and nitrogen (in ratios of 10:5) increased 2 to 4 times over non-fertilized years. The basin receiving all three nutrients consistently had blooms in late summer which were dominated by nitrogen fixing species of cyanophytes. In comparison with unfertilized reference lakes, the proportion of phytoplankton in fertilized basins which was available to zooplankton as food was 10 times greater in the basin receiving all three nutrients, and two times greater in the basin receiving only nitrogen and carbon. When fertilization of both basins was stopped, species composition and levels of biomass reverted within a year to the composition and biomass levels of phytoplankton observed in the reference lakes and remained at those levels for 2 further years of study.

Phytoplankton Productivity Changes in a Small, Double-Basin Lake in Response to Termination of Experimental Fertilization

1987 ◽  
Vol 44 (S1) ◽  
pp. s47-s54 ◽  
Author(s):  
J. A. Shearer ◽  
E. J. Fee ◽  
E. R. DeBruyn ◽  
D. R. DeClercq
Keyword(s):  
Numerical Model ◽  
Primary Production ◽  
The Other ◽  
Production Rates ◽  
Nitrogen And Phosphorus ◽  
Phytoplankton Productivity ◽  
Phytoplankton Primary Production ◽  
Carbon And Nitrogen ◽  
Model Technique ◽  
Reference Lakes

One basin of a small, double-basin lake was fertilized with carbon, nitrogen, and phosphorus for eight years, and then fertilization was stopped. The other basin was fertilized simultaneously with equivalent amounts of carbon and nitrogen only. Phytoplankton primary production was monitored using an incubator–numerical model technique. Production increased dramatically in the basin receiving artificial additions of C, N, and P. The increase was particularly large in the epilimnion where Cyanophyte blooms occurred during each year of fertilization and production rates averaged 2 to 10 times higher than in nearby, unfertilized reference lakes. Phosphorus, not nitrogen or carbon, was the critical nutrient. The productivity of the other basin also increased, but to a lesser degree and no Cyanophyte blooms were observed in this basin. When all fertilization was terminated, production in both basins immediately decreased. No more surface blooms were observed in either basin. Within 3 yr, the production had dropped to levels typical of reference lakes.

Preliminary Chemical Characterization of Waters in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 171-187 ◽  
Author(s):  
F. A. J. Armstrong ◽  
D. W. Schindler
Keyword(s):  
Chemical Characterization ◽  
Specific Conductance ◽  
Canadian Shield ◽  
Nitrogen And Phosphorus ◽  
Experimental Lakes Area ◽  
Mean Values ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen ◽  
Total Dissolved Nitrogen ◽  
Northwestern Ontario

Water analyses in 1968 and 1969 from 40 small lakes within a small area of the Canadian Shield in northwestern Ontario gave mean values for Ca, Na, Mg, and K of 1.6, 0.9, 0.9, and 0.4 mg/liter with Ca > Na > Mg > K on a molar basis. HCO3, SO4, and Cl (on a smaller number of samples) were 4.1, 3.0, and 1.4 mg/liter. Total CO2 was variable in the range 0.3–12.0 mg/liter. Specific conductance was in the range 10–35 μmho/cm at 25 C and pH 5.4–7.5. Color was < 5–150 Hazen units, and plant pigments (as chlorophyll a) < 1–21 μg/liter. Total dissolved nitrogen was in the range 110–300 mg N/liter and total dissolved phosphorus 3–20 μg P/liter. NO3-N and PO4-P were often undetectable in summer, and reached winter maxima around 100 and 10 μg/liter.Total dissolved nitrogen and phosphorus contents of five lakes were computed at the beginning and end of periods of several weeks during summer stagnation. Changes were negligibly small in three of the deeper lakes, but the two shallowest showed increases of 0.22 and 0.62 g N/m2 and 0.03 and 0.13 g P/m2. Analyses of precipitation and stream waters were used, with stream flow rates, to calculate input and output of nutrients from four of these lakes during the same periods. Retention of nutrients had occurred in all, and it was concluded that in the two deeper lakes nutrients had been lost to the sediments, whereas in the two shallower ones the increases in dissolved nutrients found were derived from the sediments.Analyses of 33 other Canadian Shield lake areas and of 13 other dilute lakes in other regions are tabulated. Comparison with the Experimental Lakes Area (ELA) lakes shows that the latter are more dilute than any in the Shield area except for some in the Northwest Territories, and much more dilute than any others in the world except for some alpine lakes in California.

Element Concentrations in Chironomids and Their Abundance in the Littoral Zone of Acidified Lakes in Northwestern Ontario

1993 ◽  
Vol 50 (5) ◽  
pp. 953-963 ◽  
Author(s):  
Vincent L. St. Louiss
Keyword(s):  
Emerging Adults ◽  
Littoral Zone ◽  
Poor Quality ◽  
Low Ph ◽  
Experimental Lakes Area ◽  
Acid Lakes ◽  
Northwestern Ontario ◽  
Accumulation Of Metals ◽  
Low Levels ◽  
Reference Lakes

I studied species diversity of the chironomid community, abundance of emerging adults, and accumulation of metals and elements in chironomids in the shallow littoral zone of experimentally acidified and unmanipulated reference lakes at the Experimental Lakes Area in northwestern Ontario. Orthocladiinae were significantly more abundant in acid lakes than in reference lakes, while the Chironominae were less numerous. The lower abundance of Chironominae resulted from fewer chironomids in the Tribe Tanytarsini. Chironomini were more common in acid lakes than in the reference lakes. Biomass of emerging chironomids either increased significantly following acidification or was not different from that of reference lakes. Concentrations of Al, Ca, Mn, and Zn were on average higher in chironomids from a number of the acid lakes than in chironomids from reference lakes. Calcium concentrations in chironomids from the most acid lake were significantly lower, however, suggesting that at low pH levels, Ca may be difficult to sequester. Increased accumulation of certain metals in chironomids, coupled with increased biomass of emerging chironomids as well as low levels of Ca, makes chironomids a potentially abundant but poor-quality food source for organisms that rely on them as prey.

Leeches (Annelida: Hirudinea) in the Experimental Lakes Area, Northwestern Ontario, Canada: Patterns of Species Composition in Relation to Environment

1994 ◽  
Vol 51 (7) ◽  
pp. 1600-1607 ◽  
Author(s):  
Brian A. Grantham ◽  
Brenda J. Hann
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Primary Productivity ◽  
Lake Area ◽  
Eutrophic Lakes ◽  
Experimental Lakes Area ◽  
Large Lakes ◽  
Northwestern Ontario

Canonical correspondence analysis (CCA) was used to examine the distribution of leeches (Annelida: Hirudinea) in 18 lakes at the Experimental Lakes Area (ELA). Leech community composition was best described by an ordination incorporating alkalinity, primary productivity, and lake area. In general, highest species richness occurred in small, eutrophic lakes whereas lowest richness was recorded in medium to large lakes with low productivity. Contrary to results for some other taxa, lake pH was not a dominant variable, describing only a small amount of variance in the species–environment relationship.

Influence of nitrogen to phosphorus supply ratios and physicochemical conditions on cyanobacteria and phytoplankton species composition in the Experimental Lakes Area, Canada

1999 ◽  
Vol 56 (3) ◽  
pp. 451-466 ◽  
Author(s):  
S N Levine ◽  
D W Schindler
Keyword(s):  
Species Composition ◽  
Nitrogen Deficiency ◽  
Late Summer ◽  
Sediment Surface ◽  
Phytoplankton Species ◽  
Low Light ◽  
Experimental Lakes Area ◽  
Phytoplankton Species Composition ◽  
N:P Ratios ◽  
Cyanobacterial Dominance

To test the hypothesis that N:P supply ratios influence phytoplankton species composition, and particularly that cyanobacteria are favored by a low ratio, mesocosms at one pelagic and two littoral sites within the Experimental Lakes Area, Ontario, were fertilized for 10-12 weeks with similar amounts of P but different amounts of N. Total N:P supply (LN:LP) ratios (fertilizer plus natural inputs) ranged from 8:1 to 50:1. Nitrogen deficiency was detected in all mesocosms with LN:LP ratios <17:1, but N2-fixing Anabaena gained dominance only in the low-N:P pelagic mesocosms, and only in late summer. Cryptophytes and (or) chlorophytes dominated littoral mesocosms at all N:P ratios, while Pseudoanabaena catenata, a nonheterocystous cyanobacterium, was the late-summer dominant in pelagic mesocosms with LN:LP ratios >17:1. Canonical correlation analysis related cyanobacterial dominance to high P and low CO2 availability. Low light intensities and low N:P ratios also favored heterocystous (but not nonheterocystous) cyanobacteria. Total phytoplankton biomass and productivity increased with LN:LP ratio, while periphyton growth was maximal at low N:P ratios. Nitrogen limitation of phytoplankton may encourage blooms of N2 fixers or drive productivity down to the sediment surface where N is more available.

Accumulation and recycling of PCBs and PAHs in artificially eutrophied Lake 227

1999 ◽  
Vol 56 (4) ◽  
pp. 650-660 ◽  
Author(s):  
Jeff D Jeremiason ◽  
Steven J Eisenreich ◽  
Michael J Paterson
Keyword(s):  
Phytoplankton Community ◽  
Sediment Accumulation ◽  
Point Sources ◽  
Accumulation Rates ◽  
Experimental Lakes Area ◽  
High Accumulation ◽  
Northwestern Ontario ◽  
Polycyclic Aromatic ◽  
Contaminant Accumulation

The influence of lake trophic status on the cycling and burial of polychlorinated biphenyls (PCB's) and polycyclic aromatic hydrocarbons (PAH's) was examined in Lake 227 (L227), an artificially eutrophied lake in the Experimental Lakes Area, northwestern Ontario, Canada. Sedimentary accumulation of PCB's, PAH's, and organic carbon (OC) was determined pre- and post-eutrophication in L227 and compared with accumulation in other regional lakes. Mass and OC accumulation increased an average of 1.4 and 2.0 times, respectively, since nutrient addition began in June 1969. ΣPCB and ΣPAH sediment accumulation rates and profiles in L227 were similar to those in Lake Superior and other proximate and midlatitude lakes unimpacted by point sources. Eutrophication did not increase contaminant accumulation. In general, individual PAH accumulation rates declined following eutrophication, which coincided with similar signals elsewhere. Perylene declined markedly (4 times) since eutrophication as a result of decreased in situ formation. An increase in OC accumulation did not enhance contaminant accumulation in L227 because phytoplankton community structure shifted to species characterized by lower bioaccumulation factors, and water column recycling rates were high. Accumulation rates of mass, OC, PCB's, and PAH's, when compared with ice-free settling fluxes in 1993 and 1994, exhibited similar recycling ratios in eutrophic L227 and oligotrophic L110 due to the efficient preservation of organic matter in sediments.

Experimental Lakes Area: Whole-Lake Experiments in Eutrophication

1974 ◽  
Vol 31 (5) ◽  
pp. 937-953 ◽  
Author(s):  
D. W. Schindler ◽  
E. J. Fee
Keyword(s):  
Algal Blooms ◽  
Large Scale ◽  
The Other ◽  
Phosphorus Fertilization ◽  
Low Carbon ◽  
Nitrogen And Phosphorus ◽  
Experimental Lakes Area ◽  
Carbon And Nitrogen ◽  
Small Phytoplankton ◽  
Carbon Concentrations

The following whole-lake experiments are described:Lake 227, fertilized for 5 yr with phosphate and nitrate, has shown an enormous increase in phytoplankton, in spite of low carbon concentrations. The carbon necessary for production of algal blooms was found to invade from the atmosphere.Lake 304, eutrophied by fertilization with phosphorus, nitrogen, and carbon in 1971 and 1972, recovered rapidly when phosphorus fertilization was terminated.Lake 226 was split in half with a curtain. One half was fertilized with carbon and nitrogen and the other was fertilized with phosphorus, carbon, and nitrogen. The half of the lake receiving phosphorus developed an algal bloom and the other half did not.Lake 302, which had carbon, nitrogen, and phosphorus added to the hypolimnion, did not develop algal blooms in summer. Small phytoplankton blooms were found under ice in early December, but all nutrients were efficiently sedimented and unavailable the following year.The above studies illustrate clearly that phosphorus control is an efficient primary step in preventing or checking eutrophication problems.A review of other published and ongoing studies in the Experimental Lakes Area is given, illustrating the role which large-scale experiments can play in interpreting environmental problems.

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