Articles & Publications
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- Author(s):
- Cottingham, K.L.
- Abstract:
Anthropogenic alterations of nutrient inputs and food-web structure are two of the primary stressors affecting lake phytoplankton. This paper explores the independent and interactive effects of nutrients and food-web structure (as indexed by zooplankton size) on phytoplankton size structure by fitting time-series models to data from three lakes where both factors have been manipulated. I assessed phytoplankton size structure using three different approaches: small and large size classes, norm…
- Date Published:
- 1999
- Record Visibility:
- Public
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- Author(s):
- Van de Bogert, M.C., S. R. Carpenter, J. J. Cole, M. L. Pace
- Abstract:
Automated in situ sensors for measuring changes in dissolved oxygen (DO) at high frequency have facilitated estimates of gross primary production (GPP) and respiration ® in aquatic systems. Lake researchers usually rely on a single sensor for these estimates, but such point measurements may miss important spatial heterogeneity in within-lake processes and may not accurately represent systemwide values of metabolism. Here we combine simultaneous measurements of metabolism using DO sensors al…
- Date Published:
- 2007
- Record Visibility:
- Public
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- Author(s):
- Bade, D. L., S. R. Carpenter, J. J. Cole, P. C. Hanson, R. H. Hesslein
- Abstract:
We investigated d 13carbon ©–dissolved inorganic carbon (DIC) values in 72 lakes from diverse regions using literature data as well as new measurements for 32 lakes. d 13C-DIC varied broadly among lakes from 231 to 12.6‰. This variation of surface-water d 13C-DIC among lakes is greater than the seasonal variation within most lakes. Several statistical models account for a large portion of the interlake variation and indicate that geochemical (e.g., DIC, pH, alkalinity) and morphometric (are…
- Date Published:
- 2004
- Record Visibility:
- Public
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- Author(s):
- M. L. Pace, J. J. Cole
- Abstract:
Food webs in three lakes were manipulated by altering fish communities to promote or suppress the abundance of large Daphnia. These lakes and an unmanipulated reference lake were monitored for 2 yr. The three experimental lakes were then fertilized for 2 yr with nitrogen and phosphorus. Bacterial responses to these manipulations were examined by means of weekly measurements of abundance and production. Bacterial production, measured both by thymidine and leucine incorporation, increased subst…
- Date Published:
- 1996
- Record Visibility:
- Public
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- Author(s):
- Van de Bogert, M. C., S. R. Carpenter, J. J. Cole, M. L. Pace
- Abstract:
Automated in situ sensors for measuring changes in dissolved oxygen (DO) at high frequency have facilitated estimates of gross primary production (GPP) and respiration ® in aquatic systems. Lake researchers usually rely on a single sensor for these estimates, but such point measurements may miss important spatial heterogeneity in within-lake processes and may not accurately represent systemwide values of metabolism. Here we combine simultaneous measurements of metabolism using DO sensors al…
- Date Published:
- 2007
- Record Visibility:
- Public
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- Author(s):
- M. L. Pace, J. J. Cole
- Abstract:
Temporal variation in dissolved organic carbon (DOC) and water color (light absorption at 440 nm) was measured in 20 lakes in northern Michigan that varied in DOC, pH, morphometry, and relative productivity as indicated by chlorophyll and total phosphorus (TP). Monthly observations during May—August over 6 yr revealed that DOC and color varied by 6- and 28-fold among lakes and varied substantially through time within lakes. The pattern of temporal variation differed among years but was synchr…
- Date Published:
- 2002
- Record Visibility:
- Public
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7
Article
- Author(s):
- Zicker, E. L.
- Abstract:
The paper reports the results of some laboratory investigations concerning the mud-water phosphorus relationship of some Northern Wisconsin and Upper Michigan bog lake muds as influenced by lime, acid, and mechanical agitation. Calcium carbonate added to the water phase of mud-water systems reduced the amount of soluble phosphorus from 8.0 to 0.8 parts per billion. The lime formed a thin crust at the mud-water interface, while the original pH of the bottom material prevailed at a depth of one…
- Date Published:
- 1956
- Record Visibility:
- Public
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- Author(s):
- Dodson, S.
- Abstract:
Amplitude of diel vertical migration is predicted by water clarity measured by Secchi depth. The model assumes that vertical migration serves to minimize mortality from visually feeding fish and to maximize grazing rate within this predation context. Three of the 24 observations of diel vertical migration are outliers which are either ultraoligotrophic, or have minimal populations of plankton-eating fish, or both. The other 21 observations in lakes with average photosynthetic rates ≳300 mg C …
- Date Published:
- 1990
- Record Visibility:
- Public
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- Author(s):
- Hansson, L.-A.
- Abstract:
I assessed the importance of algal recruitment from the sediment surface to the water relative to other population variables such as grazing, growth, and sinking. In four low-productivity lake basins, which were stratified throughout the study, 32% of the identified algal taxonomic groups exhibited recruitment, whereas the other 68% spent their entire lives in the pelagic habitat. For most species, recruitment from sediment to water occurred primarily at shallow depths (<8 m) and often inc…
- Date Published:
- 1996
- Record Visibility:
- Public
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- Author(s):
- Koenings, J. P.
- Abstract:
A sampler and an analytical and characterization scheme were developed to investigate the chemical and physical state of iron in a highly stained acid bog lake (North Gate Lake). Iron fractions were chemically separated by reactivity to bathophenanthroline (BPN) after specific digestion procedures. Physical separation by anaerobic in situ filtration (450 nm) and in situ dialysis (4.8 nm) resulted in three size classes: particulate, colloidal, and dissolved. Inorganic, nonreactive species of i…
- Date Published:
- 1976
- Record Visibility:
- Public
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- Author(s):
- Y. Vadeboncoeur, D. M. Lodge
- Abstract:
Estimates of epipelic algal primary production using 14C are sensitive to whether the presumptive source of dissolved inorganic carbon (DIC) is the overlying water, the interstitial water, or both. To determine the source of DIC, we compared 14C uptake among intact sediment cores exposed to different 14C ratios between interstitial and overlying water. In addition, we evaluated the effect of varying time between addition of 14C and light incubation (preincubation time) and the effect of photo…
- Date Published:
- 1998
- Record Visibility:
- Public
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- Author(s):
- Van de Bogert, M. C., Bade, D. L., S. R. Carpenter, J. J. Cole, M. L. Pace, P. C. Hanson, O. C. Langman
- Abstract:
To characterize the spatial variability of metabolism estimates (gross primary production [GPP], respiration [R], and net ecosystem production [NEP]) in two Northern Wisconsin lakes, we collected data from 27 and 35 dissolved oxygen sensors placed in a two-dimensional array throughout the upper mixed layers over a period of 10 d per lake in midsummer. Averaged over the deployment, aerial metabolism estimates among sensor locations varied 1–2 orders of magnitude and were largely unrelated to p…
- Date Published:
- 2012
- Record Visibility:
- Public