Journal of the American Water Resources Association, 1978
Habitat diversity and invertebrate drift were studied in a group of natural and channelized tribu... more Habitat diversity and invertebrate drift were studied in a group of natural and channelized tributaries of the upper Des Moines River during 1974 and 1975. Channelized streams in this region had lower sinuosity index values than natural channel segments. There were significant (P=O.05) positive correlations between channel sinuosity and the variability of water depth and current velocity. Invertebrate drift density, expressed as biomass and total numbers, also was correlated with channel sinuosity. Channelization has decreased habitat variability and invertebrate drift density in streams of the upper Des Moines River Basin and probably has reduced the quantity of water stored in streams during periods of low flow. (KEY TERMS: aquatic insects; stream channelization; stream drift.)
A S-year series of summer temperature profiles was used to calculate the coefficient of eddy cond... more A S-year series of summer temperature profiles was used to calculate the coefficient of eddy conductivity in a small (20.1 ha) mountain lake. The relatively high value obtained (6.22 ~10~' g cm-l set-I) prompted us to evaluate the role of direct solar heating in the hypolimnion using data on total daily solar radiation, the spectral curve of sunlight, and the light transmission properties of the lake water. It was found that an estimated 65-85s of the heating in the upper hypolimnion could be accounted for by direct solar heating. It is postulated that in Castle Lake direct solar heating rather than turbulent mixing is responsible for the shape of the hypolimnetic thermal profile. LNTRODUCTION
Synchronous interannual variability in water transparency observed in neighboring lakes has been ... more Synchronous interannual variability in water transparency observed in neighboring lakes has been linked to regional precipitation and resultant runoff of dissolved organic material, but many climate forcings oscillate over time scales longer than most limnological records can detect. A strong relationship (R 2 5 0.86) between transparency and the previous two years' rainfall and lake stage in a 25-yr record from a Florida lake enabled us to hindcast transparency from a longer 75-yr record of rainfall and lake stage. Predictions revealed a ,30-yr cycle in transparency linked to the Atlantic Multidecadal Oscillation (AMO). Transparency was greatest (4-8 m) in the cool phase of the AMO (,1962AMO (, -1993 associated with below-average rainfall in south Florida and lowest (0.1-3.0 m) during two warm phases (,1932-1961, 1994-present) associated with above-average, but more variable, annual rainfall. Models that predict effects of large-scale hydrologic restoration projects on solute export from South Florida's expansive wetlands need to account for recent entry into a warm AMO phase, where teleconnections between the AMO phases and runoff are opposite of those shown for the U.S. interior.
Journal of the North American Benthological Society, 1991
... Traditionally, our pedagogic approach has been to define the prob-lem narrowly so that it cou... more ... Traditionally, our pedagogic approach has been to define the prob-lem narrowly so that it could be addressed by students within a single discipline or subdiscipline. ... Kent W. Thornton Bruce L. Kimmel Forrest E. Payne Little Rock, Arkansas Oak Ridge, Tennessee Page 9. ...
Page 1. Journal of Plankton Research Vol.16 no. I pp.53-68. 1994 Seasonally, substrate preference... more Page 1. Journal of Plankton Research Vol.16 no. I pp.53-68. 1994 Seasonally, substrate preference and attachment sites of epizoic diatoms on cladoceran zooplankton Evelyn E.Gaiser1 and Roger W.Bachmann2 Department ...
... Roger W. Bachmann & Daniel E. Canfield Jr ... This use of second deriva-tive spectroscopy... more ... Roger W. Bachmann & Daniel E. Canfield Jr ... This use of second deriva-tive spectroscopy for the determination of N03 -N was first proposed by Simal et al., (1985) and was found by Wollin (1987) to have a high degree of accuracy and precision for the determination of N03 -N in ...
Fundamental and Applied Limnology / Archiv für Hydrobiologie, 2009
Lake Annie is a small (37 ha), relatively deep (21 m) sinkhole lake on the Lake Wales Ridge (LWR)... more Lake Annie is a small (37 ha), relatively deep (21 m) sinkhole lake on the Lake Wales Ridge (LWR) of central Florida with a long history of study, including monthly limnological monitoring since June, 1983. The record shows high variability in Secchi disc transparency, which ranged from < 1 to 15 m with a trend toward decreasing values over the latter decade of record. We examined available regional meteorological, groundwater and limnological data to determine the drivers and thermal consequences of variability in water transparency. While total nutrient concentrations and chlorophyll-a were highest during years of low transparency, stepwise regression showed that none of these had a signifi cant effect on transparency after water color was taken into account. Repeated years of high precipitation between 1993-2005 caused an increase in water table height, increasing the transport of dissolved substances from the vegetated watershed into the lake. Groundwater stage explained 73 % of the interannual variability in water transparency. Transparency, in turn, explained 85 % of the interannual variability in the heat budget for the lake, which ranged from 1.8 × 10 8 to 4.1 × 10 8 Joules m -2 yr -1 , encompassing the range reported across Florida lakes. While surface water temperature was not affected by transparency, depths below 5 m warmed faster during the stratifi ed period during years having a lower rate of light extinction. We show that an increase in precipitation of 20 cm per year reduces the depth of the summer euphotic zone and thermocline by 1.9 and 1.6 m, respectively, and causes a 1-month reduction in the duration of winter mixing in this monomictic lake. Because biota have been shown to respond to shifts in light and heat distribution of much smaller magnitude than exhibited here, our work suggests that subtle changes in precipitation linked to climate fl uctuations may have signifi cant physical as well as biotic consequences.
Canadian Journal of Fisheries and Aquatic Sciences, 1984
... Phosphorus was analyzed according to the procedures of Murphy and Riley (1962) with a persulf... more ... Phosphorus was analyzed according to the procedures of Murphy and Riley (1962) with a persulfate oxidation (Menzel and Cor-win 1965). ... the lake bottom, we located a network of stations on a bathymetric map of the lake and calculated the effective fetch for that wind for each ...
... lakes Roger W. Bachmann 1 , Dana L. Bigham, Mark V. Hoyer and Daniel E. Canfield, Jr. ... dev... more ... lakes Roger W. Bachmann 1 , Dana L. Bigham, Mark V. Hoyer and Daniel E. Canfield, Jr. ... development. As a result Florida lake trophic states have not changed during a period of intense human population growth (Terrell et al. 2000). ...
ABSTRACT We found the conclusion of SCHELSKE et al. (2003, Arch. Hydrobiol. 157 : 145-172) that L... more ABSTRACT We found the conclusion of SCHELSKE et al. (2003, Arch. Hydrobiol. 157 : 145-172) that Lake Apopka was not net heterotrophic was incorrect when annual rates of production and respiration for the entire lake ecosystem are taken into consideration. A new carbon budget for the water and sediments showed for the period of study the sum of the annual sources of organic carbon including primary production and inflows (765 g C m−2 yr−1) was less than the sum of the annual losses including respiration in the water and sediments and outflows (2497 g C m−2 yr−1). Diel oxygen curves demonstrated that it is possible to have oxygen supersaturation at the surface near midday and still have net heterotrophy over 24-h.
Canadian Journal of Fisheries and Aquatic Sciences, 2000
... TN concentrations (micro-grams per litre) were determined by·oxidizing water samples with per... more ... TN concentrations (micro-grams per litre) were determined by·oxidizing water samples with persulfate and determining nitrate-N with second-derivative spec-troscopy ... The same sigmoid curve was tilen compared with a linear regression line fitted to the global data set. ...
ABSTRACT Because the use of volunteer samplers is a very cost-effective way to collect large amou... more ABSTRACT Because the use of volunteer samplers is a very cost-effective way to collect large amounts of information on lakes over space and time, we studied the reliability of the protocols used by the Florida LAKEWATCH program. We found that chlorophyll ...
Recent changes in submersed macrophytes and water quality variables have been offered as the stro... more Recent changes in submersed macrophytes and water quality variables have been offered as the strongest evidence that the current restoration program at Lake Apopka will be effective (Lowe et al., 2000); however, the new beds of submersed plants in Lake Apopka are found only on hard substrates on the fringes of the lake within 40 m of shore and are protected from waves by cattails (Typha spp.). They occupy only 0.02% of the lake area, and there is no indication that they can colonize the flocculent sediments that make up 90% of the lake area. There is no correlation between annual inputs of phosphorus and total phosphorus concentrations in the lake, and patterns of change in chlorophyll and other water quality variables do not follow changes in phosphorus loads. Rather than reflecting decreases in phosphorus loading, the recent changes could be related to the harvest of benthivorous fish or are just the normal fluctuations found in lakes that have not been perturbed. Regardless of the reason the macrophytes were lost in the 1940s, the new analyses confirm our previous findings that the high turbidities in Lake Apopka are due to the resuspension of sediments, and that the fluid mud cannot support the colonization of submersed aquatic macrophytes. Even without the fluid mud, the target phosphorus concentration of 55 mg m −3 is too high to bring about the restoration of the former macrophyte beds in the lake.
We collected quantitative data on macrophyte abundance and water quality in 319 mostly shallow, p... more We collected quantitative data on macrophyte abundance and water quality in 319 mostly shallow, polymictic, Florida lakes to look for relationships between trophic state indicators and the biomasses of plankton algae, periphyton, and macrophytes. The lakes ranged from oligotrophic to hypereutrophic with total algal chlorophylls ranging from 1 to 241 mg m −3 . There were strong positive correlations between planktonic chlorophylls and total phosphorus and total nitrogen, but there were weak inverse relationships between the densities of periphyton and the trophic state indicators total phosphorus, total nitrogen and algal chlorophyll and a positive relationship with Secchi depth. There was no predictable relationship between the abundance of emergent, floating-leaved, and submersed aquatic vegetation and the trophic state indicators. It was only at the highest levels of nutrient concentrations that submersed macrophytes were predictably absent and the lakes were algal dominated. Below these levels, macrophyte abundance could be high or low. The phosphorus-chlorophyll and phosphorus-Secchi depth relationships were not influenced by the amounts of aquatic vegetation present indicating that the role of macrophytes in clearing lakes may be primarily to reduce nutrient concentrations for a given level of loading. Rather than nutrient concentrations controlling macrophyte abundance, it seems that macrophytes acted to modify nutrient concentrations.
We examined data on CO 2 and related limnological and geographic information from a sample of 948... more We examined data on CO 2 and related limnological and geographic information from a sample of 948 Florida freshwater lakes. The objectives for this study were (1) to determine the partial pressures of carbon dioxide (qCO 2 ) in the surface waters of a large sample of Florida lakes, (2) to determine if several limnological or geographic factors are related to levels of qCO 2 in Florida lakes, and (3) to estimate the net annual rate of loss of CO 2 to the atmosphere from the freshwater lakes of Florida. The calculated qCO 2 for the lakes in our sample range from 0 to 81,000 latm, with a mean of 3,550 latm, a median of 1,030 latm, and a geometric mean of 1,270 latm. About 87% of the Florida lakes were supersaturated with CO 2 . There were statistically significant correlations between values for qCO 2 and several water chemistry variables; however, the R 2 values were small and accounted for only a small portion of the variance. In general the qCO 2 values were higher in the lakes with low alkalinities and low contents of dissolved salts. The best predictor of qCO 2 is pH, with an R 2 of 0.82 for a polynomial relationship. The qCO 2 values tend to decrease from northwest to southeast across the state of Florida, which corresponds to the gradients we found for pH, alkalinity, and specific conductance. The average areal rate of carbon emission from the Florida lakes was 328 g C m -2 y -1 , and the total carbon loss for the lakes and ponds of Florida was 2.0 Tg y -1 . This amounts to about 2% of the total carbon emissions from all the lakes of the world as estimated by previous studies.
Journal of the American Water Resources Association, 1978
Habitat diversity and invertebrate drift were studied in a group of natural and channelized tribu... more Habitat diversity and invertebrate drift were studied in a group of natural and channelized tributaries of the upper Des Moines River during 1974 and 1975. Channelized streams in this region had lower sinuosity index values than natural channel segments. There were significant (P=O.05) positive correlations between channel sinuosity and the variability of water depth and current velocity. Invertebrate drift density, expressed as biomass and total numbers, also was correlated with channel sinuosity. Channelization has decreased habitat variability and invertebrate drift density in streams of the upper Des Moines River Basin and probably has reduced the quantity of water stored in streams during periods of low flow. (KEY TERMS: aquatic insects; stream channelization; stream drift.)
A S-year series of summer temperature profiles was used to calculate the coefficient of eddy cond... more A S-year series of summer temperature profiles was used to calculate the coefficient of eddy conductivity in a small (20.1 ha) mountain lake. The relatively high value obtained (6.22 ~10~' g cm-l set-I) prompted us to evaluate the role of direct solar heating in the hypolimnion using data on total daily solar radiation, the spectral curve of sunlight, and the light transmission properties of the lake water. It was found that an estimated 65-85s of the heating in the upper hypolimnion could be accounted for by direct solar heating. It is postulated that in Castle Lake direct solar heating rather than turbulent mixing is responsible for the shape of the hypolimnetic thermal profile. LNTRODUCTION
Synchronous interannual variability in water transparency observed in neighboring lakes has been ... more Synchronous interannual variability in water transparency observed in neighboring lakes has been linked to regional precipitation and resultant runoff of dissolved organic material, but many climate forcings oscillate over time scales longer than most limnological records can detect. A strong relationship (R 2 5 0.86) between transparency and the previous two years' rainfall and lake stage in a 25-yr record from a Florida lake enabled us to hindcast transparency from a longer 75-yr record of rainfall and lake stage. Predictions revealed a ,30-yr cycle in transparency linked to the Atlantic Multidecadal Oscillation (AMO). Transparency was greatest (4-8 m) in the cool phase of the AMO (,1962AMO (, -1993 associated with below-average rainfall in south Florida and lowest (0.1-3.0 m) during two warm phases (,1932-1961, 1994-present) associated with above-average, but more variable, annual rainfall. Models that predict effects of large-scale hydrologic restoration projects on solute export from South Florida's expansive wetlands need to account for recent entry into a warm AMO phase, where teleconnections between the AMO phases and runoff are opposite of those shown for the U.S. interior.
Journal of the North American Benthological Society, 1991
... Traditionally, our pedagogic approach has been to define the prob-lem narrowly so that it cou... more ... Traditionally, our pedagogic approach has been to define the prob-lem narrowly so that it could be addressed by students within a single discipline or subdiscipline. ... Kent W. Thornton Bruce L. Kimmel Forrest E. Payne Little Rock, Arkansas Oak Ridge, Tennessee Page 9. ...
Page 1. Journal of Plankton Research Vol.16 no. I pp.53-68. 1994 Seasonally, substrate preference... more Page 1. Journal of Plankton Research Vol.16 no. I pp.53-68. 1994 Seasonally, substrate preference and attachment sites of epizoic diatoms on cladoceran zooplankton Evelyn E.Gaiser1 and Roger W.Bachmann2 Department ...
... Roger W. Bachmann & Daniel E. Canfield Jr ... This use of second deriva-tive spectroscopy... more ... Roger W. Bachmann & Daniel E. Canfield Jr ... This use of second deriva-tive spectroscopy for the determination of N03 -N was first proposed by Simal et al., (1985) and was found by Wollin (1987) to have a high degree of accuracy and precision for the determination of N03 -N in ...
Fundamental and Applied Limnology / Archiv für Hydrobiologie, 2009
Lake Annie is a small (37 ha), relatively deep (21 m) sinkhole lake on the Lake Wales Ridge (LWR)... more Lake Annie is a small (37 ha), relatively deep (21 m) sinkhole lake on the Lake Wales Ridge (LWR) of central Florida with a long history of study, including monthly limnological monitoring since June, 1983. The record shows high variability in Secchi disc transparency, which ranged from < 1 to 15 m with a trend toward decreasing values over the latter decade of record. We examined available regional meteorological, groundwater and limnological data to determine the drivers and thermal consequences of variability in water transparency. While total nutrient concentrations and chlorophyll-a were highest during years of low transparency, stepwise regression showed that none of these had a signifi cant effect on transparency after water color was taken into account. Repeated years of high precipitation between 1993-2005 caused an increase in water table height, increasing the transport of dissolved substances from the vegetated watershed into the lake. Groundwater stage explained 73 % of the interannual variability in water transparency. Transparency, in turn, explained 85 % of the interannual variability in the heat budget for the lake, which ranged from 1.8 × 10 8 to 4.1 × 10 8 Joules m -2 yr -1 , encompassing the range reported across Florida lakes. While surface water temperature was not affected by transparency, depths below 5 m warmed faster during the stratifi ed period during years having a lower rate of light extinction. We show that an increase in precipitation of 20 cm per year reduces the depth of the summer euphotic zone and thermocline by 1.9 and 1.6 m, respectively, and causes a 1-month reduction in the duration of winter mixing in this monomictic lake. Because biota have been shown to respond to shifts in light and heat distribution of much smaller magnitude than exhibited here, our work suggests that subtle changes in precipitation linked to climate fl uctuations may have signifi cant physical as well as biotic consequences.
Canadian Journal of Fisheries and Aquatic Sciences, 1984
... Phosphorus was analyzed according to the procedures of Murphy and Riley (1962) with a persulf... more ... Phosphorus was analyzed according to the procedures of Murphy and Riley (1962) with a persulfate oxidation (Menzel and Cor-win 1965). ... the lake bottom, we located a network of stations on a bathymetric map of the lake and calculated the effective fetch for that wind for each ...
... lakes Roger W. Bachmann 1 , Dana L. Bigham, Mark V. Hoyer and Daniel E. Canfield, Jr. ... dev... more ... lakes Roger W. Bachmann 1 , Dana L. Bigham, Mark V. Hoyer and Daniel E. Canfield, Jr. ... development. As a result Florida lake trophic states have not changed during a period of intense human population growth (Terrell et al. 2000). ...
ABSTRACT We found the conclusion of SCHELSKE et al. (2003, Arch. Hydrobiol. 157 : 145-172) that L... more ABSTRACT We found the conclusion of SCHELSKE et al. (2003, Arch. Hydrobiol. 157 : 145-172) that Lake Apopka was not net heterotrophic was incorrect when annual rates of production and respiration for the entire lake ecosystem are taken into consideration. A new carbon budget for the water and sediments showed for the period of study the sum of the annual sources of organic carbon including primary production and inflows (765 g C m−2 yr−1) was less than the sum of the annual losses including respiration in the water and sediments and outflows (2497 g C m−2 yr−1). Diel oxygen curves demonstrated that it is possible to have oxygen supersaturation at the surface near midday and still have net heterotrophy over 24-h.
Canadian Journal of Fisheries and Aquatic Sciences, 2000
... TN concentrations (micro-grams per litre) were determined by·oxidizing water samples with per... more ... TN concentrations (micro-grams per litre) were determined by·oxidizing water samples with persulfate and determining nitrate-N with second-derivative spec-troscopy ... The same sigmoid curve was tilen compared with a linear regression line fitted to the global data set. ...
ABSTRACT Because the use of volunteer samplers is a very cost-effective way to collect large amou... more ABSTRACT Because the use of volunteer samplers is a very cost-effective way to collect large amounts of information on lakes over space and time, we studied the reliability of the protocols used by the Florida LAKEWATCH program. We found that chlorophyll ...
Recent changes in submersed macrophytes and water quality variables have been offered as the stro... more Recent changes in submersed macrophytes and water quality variables have been offered as the strongest evidence that the current restoration program at Lake Apopka will be effective (Lowe et al., 2000); however, the new beds of submersed plants in Lake Apopka are found only on hard substrates on the fringes of the lake within 40 m of shore and are protected from waves by cattails (Typha spp.). They occupy only 0.02% of the lake area, and there is no indication that they can colonize the flocculent sediments that make up 90% of the lake area. There is no correlation between annual inputs of phosphorus and total phosphorus concentrations in the lake, and patterns of change in chlorophyll and other water quality variables do not follow changes in phosphorus loads. Rather than reflecting decreases in phosphorus loading, the recent changes could be related to the harvest of benthivorous fish or are just the normal fluctuations found in lakes that have not been perturbed. Regardless of the reason the macrophytes were lost in the 1940s, the new analyses confirm our previous findings that the high turbidities in Lake Apopka are due to the resuspension of sediments, and that the fluid mud cannot support the colonization of submersed aquatic macrophytes. Even without the fluid mud, the target phosphorus concentration of 55 mg m −3 is too high to bring about the restoration of the former macrophyte beds in the lake.
We collected quantitative data on macrophyte abundance and water quality in 319 mostly shallow, p... more We collected quantitative data on macrophyte abundance and water quality in 319 mostly shallow, polymictic, Florida lakes to look for relationships between trophic state indicators and the biomasses of plankton algae, periphyton, and macrophytes. The lakes ranged from oligotrophic to hypereutrophic with total algal chlorophylls ranging from 1 to 241 mg m −3 . There were strong positive correlations between planktonic chlorophylls and total phosphorus and total nitrogen, but there were weak inverse relationships between the densities of periphyton and the trophic state indicators total phosphorus, total nitrogen and algal chlorophyll and a positive relationship with Secchi depth. There was no predictable relationship between the abundance of emergent, floating-leaved, and submersed aquatic vegetation and the trophic state indicators. It was only at the highest levels of nutrient concentrations that submersed macrophytes were predictably absent and the lakes were algal dominated. Below these levels, macrophyte abundance could be high or low. The phosphorus-chlorophyll and phosphorus-Secchi depth relationships were not influenced by the amounts of aquatic vegetation present indicating that the role of macrophytes in clearing lakes may be primarily to reduce nutrient concentrations for a given level of loading. Rather than nutrient concentrations controlling macrophyte abundance, it seems that macrophytes acted to modify nutrient concentrations.
We examined data on CO 2 and related limnological and geographic information from a sample of 948... more We examined data on CO 2 and related limnological and geographic information from a sample of 948 Florida freshwater lakes. The objectives for this study were (1) to determine the partial pressures of carbon dioxide (qCO 2 ) in the surface waters of a large sample of Florida lakes, (2) to determine if several limnological or geographic factors are related to levels of qCO 2 in Florida lakes, and (3) to estimate the net annual rate of loss of CO 2 to the atmosphere from the freshwater lakes of Florida. The calculated qCO 2 for the lakes in our sample range from 0 to 81,000 latm, with a mean of 3,550 latm, a median of 1,030 latm, and a geometric mean of 1,270 latm. About 87% of the Florida lakes were supersaturated with CO 2 . There were statistically significant correlations between values for qCO 2 and several water chemistry variables; however, the R 2 values were small and accounted for only a small portion of the variance. In general the qCO 2 values were higher in the lakes with low alkalinities and low contents of dissolved salts. The best predictor of qCO 2 is pH, with an R 2 of 0.82 for a polynomial relationship. The qCO 2 values tend to decrease from northwest to southeast across the state of Florida, which corresponds to the gradients we found for pH, alkalinity, and specific conductance. The average areal rate of carbon emission from the Florida lakes was 328 g C m -2 y -1 , and the total carbon loss for the lakes and ponds of Florida was 2.0 Tg y -1 . This amounts to about 2% of the total carbon emissions from all the lakes of the world as estimated by previous studies.
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