Temporal and Seasonal Trends in Nutrient Dynamics and Biomass Measures in Lakes Michigan and Ontario in Response to Phosphorus Control

1994 ◽  
Vol 51 (11) ◽  
pp. 2570-2578 ◽  
Author(s):  
T. H. Johengen ◽  
Ora E. Johannsson ◽  
G. Laird Pernie ◽  
E. S. Millard
Keyword(s):  
Nutrient Dynamics ◽  
Lake Michigan ◽  
Lake Ontario ◽  
Ecological Monitoring ◽  
Nutrient Utilization ◽  
Utilization Rate ◽  
Southern Basin ◽  
Utilization Patterns ◽  
Phosphorus Loads

Results from long-term ecological monitoring studies on Lake Michigan (1983–92) and Lake Ontario (1981–92) were compared with regard to changes in phosphorus loads. In Lake Ontario, total phosphorus (TP) loads decreased from 14 000 t∙yr−1 in 1970 to 7500 t∙yr−1 in 1981, and correspondingly, midlake TP concentration decreased from 25 to 16 μg∙L−1 From 1981 to 1991 TP loads remained around 7500 t∙yr−1; however, TP concentration continued to decline from 16 to 10 μg∙L−1. Similarly, mean summer particulate organic carbon (POC), chlorophyll a (CHLa), and nitrate utilization rate decreased by approximately 40, 20, and 50%, respectively. Conversely, silica utilization rates increased markedly after 1983. In Lake Michigan, TP loads also decreased by around 50% from 1974 to 1990 (2000 t∙yr−1); however, TP concentrations at our 100-m station in the southern basin increased during the study period from around 4 to 8 μg∙L−1 There were no distinct trends in CHLa or nutrient utilization patterns; however, POC levels decreased sharply after 1987. Overall, silica utilization rates in Lake Michigan were 50% higher than in Lake Ontario (14.7 vs. 9.6 μg∙L−1∙d−1), whereas nitrate utilization rates were only half (1.4 vs. 4.1 μg∙L−1∙d−1).

Long-term trends of Lake Michigan benthos with emphasis on the southern basin

2020 ◽  
Vol 46 (3) ◽  
pp. 528-537 ◽  
Author(s):  
Knut Mehler ◽  
Lyubov E. Burlakova ◽  
Alexander Y. Karatayev ◽  
Ashley K. Elgin ◽  
Thomas F. Nalepa ◽  
...  
Keyword(s):  
Lake Michigan ◽  
Southern Basin ◽  
Long Term Trends

scholarly journals New data regarding ecology of freshwater pelagic amphipod Macrohectopus branickii and other crustaceans of plankton from the southern part of Lake Baikal

2021 ◽  
Vol 7 ◽  
pp. 39-48
Author(s):  
Dmitry Yu. Karnaukhov ◽  
Ekaterina M. Dolinskaya ◽  
Sofya A. Biritskaya ◽  
Maria A. Teplykh ◽  
Yana K. Ermolaeva ◽  
...  
Keyword(s):  
Lake Baikal ◽  
Antarctic Krill ◽  
Water Layer ◽  
Ecological Monitoring ◽  
Warming Trend ◽  
Breeding Period ◽  
Southern Basin ◽  
Active Predator ◽  
Species Ecology

In this study, we present a list of crustaceans traced in plankton of the southern basin Lake Baikal in addition to some details regarding ecological peculiarities of the only known freshwater pelagic amphipod Macrohectopus branickii. The amphipod is an active predator among major parts of the Lake Baikal food chain. Its role in the lake’s ecosystem is similar to that of Antarctic krill and mysids in Europe and North America water bodies. As an active swimmer, M. branickii performs daily vertical migrations. Besides, the species also has horizontal migrations and migrating swarms, including time during breeding period, that hamper species studies. We were interested in clarify some features of the species ecology. As a material we used samples obtained in the 0 to 250 m water layer with a plankton Juday net every 7 to 10 days from 2013 until 2018 as a part of long-term ecological monitoring project of Lake Baikal pelagial. Sampling was conducted in the southern part of the lake off the shore of Bolshie Koty Village. The results showed the presence of one peak of young during breeding period, which is at its maximum in May. The maximum of the 1 to 6 mm group containing young individuals and males occurs in July, and during the same period, a slight increase in immature females in comparison with the first group can also be seen. This finding might be directly linked to the warming trend in Lake Baikal.

Evidence of recovery from phosphorus enrichment in Lake Michigan

2002 ◽  
Vol 59 (10) ◽  
pp. 1639-1647 ◽  
Author(s):  
Richard P Barbiero ◽  
Marc L Tuchman ◽  
Glenn J Warren ◽  
David C Rockwell
Keyword(s):  
Lake Michigan ◽  
Silica Content ◽  
Phosphorus Loading ◽  
Phosphorus Load ◽  
Southern Basin ◽  
Soluble Silica ◽  
Long Term Monitoring ◽  
First Time ◽  
Term Monitoring

During the last century, diatom production responses to increased phosphorus loading in Lake Michigan resulted in increased silica sedimentation losses and a consequent decline in the silica content of the lake. In light of recent reductions in phosphorus loading to the lake, we examined long-term monitoring data to determine if this trend might be reversing. Spring total phosphorus concentrations, although highly variable, declined approximately 1 μg·L–1 throughout the lake between 1983 and 2000. Spring soluble silica concentrations, an indicator of total in-lake reserves, increased from 1.1 to 1.6 mg·L–1 during this period. Summer epilimnetic silica concentrations in the southern basin were at apparently limiting levels of approximately 0.15 mg·L–1 until 1991 and then increased sharply. A similar trend was seen in the northern basin. Summer diatom populations increased in both basins after 1991, and ordination analyses suggest that the species composition of both spring and summer communities has responded to these silica increases. These results document for the first time a reversal of the silica depletion sequence and provide the most compelling evidence to date that phosphorus load reductions are having an impact on the Lake Michigan ecosystem.

Monitoring Effects of Catchment Management Practices on Phosphorus Loads into the Eutrophic Peel-Harvey Estuary, Western Australia

1986 ◽  
Vol 18 (4-5) ◽  
pp. 53-61 ◽  
Author(s):  
P. B. Birch ◽  
G. G. Forbes ◽  
N. J. Schofield
Keyword(s):  
Management Practices ◽  
Major Change ◽  
High Flow ◽  
Catchment Management ◽  
Flow Rates ◽  
Early Results ◽  
Phosphorus Loads ◽  
Time Of Year ◽  
High Runoff

Early results from monitoring runoff suggest that the programme to reduce application of superphosphate to farmlands in surrounding catchments has been successful in reducing input of phosphorus to the eutrophic Peel-Harvey estuary. In the estuary this phosphorus fertilizes algae which grow in abundance and accumulate and pollute once clean beaches. The success of the programme has been judged from application of an empirical statistical model, which was derived from 6 years of data from the Harvey Estuary catchment prior to a major change in fertilizer practices in 1984. The model relates concentration of phosphorus with rate of flow and time of year. High phosphorus concentrations were associated with high flow rates and with flows early in the high runoff season (May-July). The model predicted that the distribution of flows in 1984 should have resulted in a flow-weighted concentration of phosphorus near the long-term average; the observed concentration was 25% below the long-term average. This means that the amount of phosphorus discharged into the Harvey Estuary could have been about 2 5% less than expected from the volume of runoff which occurred. However several more years of data are required to confirm this trend.

Opioid Consumption Patterns and Prolonged Opioid Use Among Opioid-Naïve Ankle Fracture Patients

2021 ◽  
pp. 193864002199292
Author(s):  
Hope Skibicki ◽  
Sundeep Saini ◽  
Ryan Rogero ◽  
Kristen Nicholson ◽  
Rachel J. Shakked ◽  
...  
Keyword(s):  
Ankle Fracture ◽  
Monitoring Program ◽  
Opioid Consumption ◽  
Consumption Patterns ◽  
Utilization Rate ◽  
Opioid Use ◽  
Index Procedure ◽  
Postoperative Visit ◽  
Fracture Surgery

Introduction Previous literature has demonstrated an association between acute opioid exposure and the risk of long-term opioid use. Here, the investigators assess immediate postoperative opioid consumption patterns as well as the incidence of prolonged opioid use among opioid-naïve patients following ankle fracture surgery. Methods Included patients underwent outpatient open reduction and internal fixation of an ankle or tibial plafond fracture over a 1-year period. At patients’ first postoperative visit, opioid pills were counted and standardized to the equivalent number of 5-mg oxycodone pills. Prolonged use was defined as filling a prescription for a controlled substance more than 90 days after the index procedure, tracked by the New Jersey Prescription Drug Monitoring Program up to 1 year postoperatively. Results At the first postoperative visit, 173 patients consumed a median of 24 out of 40 pills prescribed. The initial utilization rate was 60%, and 2736 pills were left unused. In all, 32 (18.7%) patients required a narcotic prescription 90 days after the index procedure. Patients with a self-reported history of depression (P = .11) or diabetes (P = .07) demonstrated marginal correlation with prolonged narcotic use. Conclusion Our study demonstrated that, on average, patients utilize significantly fewer opioid pills than prescribed and that many patient demographics are not significant predictors of continued long-term use following outpatient ankle fracture surgery. Large variations in consumption rates make it difficult for physicians to accurately prescribe and predict prolonged narcotic use. Level of Evidence: Level III

Nutrient cycling differs between cropped soils with century-old and recently pyrolyzed biochar

2021 ◽  
Author(s):  
Victor Burgeon ◽  
Julien Fouché ◽  
Sarah Garré ◽  
Ramin Heidarian-Dehkordi ◽  
Gilles Colinet ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Soil Solution ◽  
Nutrient Dynamics ◽  
Chemical Properties ◽  
Crop Productivity ◽  
Nutrient Concentrations ◽  
Soil Productivity ◽  
Long Term Effects ◽  
Mitigation And Adaptation

<p>The amendment of biochar to soils is often considered for its potential as a climate change mitigation and adaptation tool through agriculture. Its presence in tropical agroecosystems has been reported to positively impact soil productivity whilst successfully storing C on the short and long-term. In temperate systems, recent research showed limited to no effect on productivity following recent biochar addition to soils. Its long-term effects on productivity and nutrient cycling have, however, been overlooked yet are essential before the use of biochar can be generalized.</p><p>Our study was set up in a conventionally cropped field, containing relict charcoal kiln sites used as a model for century old biochar (CoBC, ~220 years old). These sites were compared to soils amended with recently pyrolyzed biochar (YBC) and biochar free soils (REF) to study nutrient dynamics in the soil-water-plant system. Our research focused on soil chemical properties, crop nutrient uptake and soil solution nutrient concentrations. Crop plant samples were collected over three consecutive land occupations (chicory, winter wheat and a cover crop) and soil solutions gathered through the use of suctions cups inserted in different horizons of the studied Luvisol throughout the field.</p><p>Our results showed that YBC mainly influenced the soil solution composition whereas CoBC mainly impacted the total and plant available soil nutrient content. In soils with YBC, our results showed lower nitrate and potassium concentrations in subsoil horizons, suggesting a decreased leaching, and higher phosphate concentrations in topsoil horizons. With time and the oxidation of biochar particles, our results reported higher total soil N, available K and Ca in the topsoil horizon when compared to REF, whereas available P was significantly smaller. Although significant changes occurred in terms of plant available nutrient contents and soil solution nutrient concentrations, this did not transcend in variations in crop productivity between soils for neither of the studied crops. Overall, our study highlights that young or aged biochar behave as two distinct products in terms of nutrient cycling in soils. As such the sustainability of these soils differ and their management must therefore evolve with time.</p>

scholarly journals Subglacial water-sheet floods, drumlins and ice-sheet lobes

1999 ◽  
Vol 45 (150) ◽  
pp. 201-213 ◽  
Author(s):  
E.M. Shoemaker
Keyword(s):  
New York ◽  
Lake Michigan ◽  
New York State ◽  
Ice Sheet ◽  
Lake Ontario ◽  
High Water ◽  
Green Bay ◽  
Subglacial Lake ◽  
Western Lake ◽  
Subglacial Lakes

AbstractThe effect of subglacial lakes upon ice-sheet topography and the velocity patterns of subglacial water-sheet floods is investigated. A subglacial lake in the combined Michigan–Green Bay basin, Great Lakes, North America, leads to: (1) an ice-sheet lobe in the lee of Lake Michigan; (2) a change in orientations of flood velocities across the site of a supraglacial trough aligned closely with Green Bay, in agreement with drumlin orientations; (3) low water velocities in the lee of Lake Michigan where drumlins are absent; and (4) drumlinization occurring in regions of predicted high water velocities. The extraordinary divergence of drumlin orientations near Lake Ontario is explained by the presence of subglacial lakes in the Ontario and Erie basins, along with ice-sheet displacements of up to 30 km in eastern Lake Ontario. The megagrooves on the islands in western Lake Erie are likely to be the product of the late stage of a water-sheet flood when outflow from eastern Lake Ontario was dammed by displaced ice and instead flowed westward along the Erie basin. The Finger Lakes of northern New York state, northeastern U.S.A., occur in a region of likely ice-sheet grounding where water sheets became channelized. Green Bay and Grand Traverse Bay are probably the products of erosion along paths of strongly convergent water-sheet flow.

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