Ecosystem studies and mathematical model for Lake ...
Warnke, D.A., J . Richter, and C. Oppenheimer. 1973. Characteristics of the nearshore environment off the south coast of Anvers Island, Antarctic Peninsula. Liinnology and Oceanography, 18: 131-142.
—Wood
Ecosystem studies and mathematical model for Lake Bonney, Taylor Valley, southern Victoria Land LEONARD W. HOWELL, JR., RICHARD G. KRUTCHKOFF, and BRUCE C. PARKER
Virginia Polytechnic Institute and State Unwersity Blacksburg, Virginia 24061 The fifth and final austral summer of our study of the Lake Bonney ecosystem pursuant to a mathematical model was undertaken from November 1976 to January 1977. Measurements throughout the season included dissolved 02, pH, sulfates, NH,,-N, NO 3 -N, NO 2 -N, primary productivity, algal counts, temperature, alkalinity, and PO 4 -P. Increasing emphasis was given to assessment of glacial meltwater input to the lake, inorganic nitrogen and orthophosphorus composition of the meltwater and the icecemented permafrost, and a new investigation of carbon-14 organic substrate uptake by the plankton microorganisms. These data will be reported subsequently following detailed analysis and interpretation. In addition, we are investigating the growth of Lake Bonney, the volume of which has more than doubled since its discovery and description by Scott's field party in 1903. The lake's growth in recent years is emphasized by the necessity to abandon the hut in January 1977 when the water level reached its foundation (figure 1). This hut was erected in 1962 and was several meters above Lake Bonney ice at that time. The remainder of this report describes the mathematical model, now nearly complete and to our knowledge the first such model for an arheic, meromictic lake. Our modeling approach for the Lake Bonney ecosystem has been to employ three categories of information to develop a model as a tool for exploring interactions between various lake organisms and their environments. These three categories are (1) real data or measurements taken at Lake Bonney (e.g., nutrient levels, productivity rates), (2) real data or measurements from other aquatic ecosystems (e.g., nutrient uptake rates, cell composition) and (3) intuitive guesses (e.g., death rates, consumption rates). The Lake Bonney model is deterministic and consists of 21 simultaneous differential equations, 21 parametric equations, 42 submodels, and 180 coefficients. We have written a FORTRAN program that solves these equations numerically, giving the solutions graphically and/or in tabular form. Four programs permit a variety of input-output options. October 1977
Figure 1. Lake Bonney hut (built 1962) and analytical chemistry lab (built 1971) in early January 1977, showing lake water surrounding the hut and at a level nearly touching the foundation. Each program calls each of the subprograms, and many of the subprograms call each other as they run on the IBM 370/158 computer. Other important features of the model are mass-balance, which checks the consistency of the equations, and a confidence interval submodel that allows for confidence intervals in prediction. Differential equations used in our model consist of derivatives of biomass and nutrient (or other variable) concentrations with respect to time, as follows: (1) suspended (plankton) algae, (2) suspended (plankton) bacteria, (3) suspended (plankton) yeasts, (4) water column phosphorus, (5) water column inorganic nitrogen, (6) water column inorganic carbon, (7) water column particulate organic matter (nonliving), (8) water column dissolved organic matter, (9) water column dissolved oxygen, (10) mat algae (referring to benthic attached felts), (11) mat yeasts, (12) mat bacteria, (13) mat consumers (referring to ciliates, rotifers, tardigrades and nematodes in mats and which are not found in the plankton), (14) mat inorganic nitrogen, (15) mat phosphorus, (16) mat inorganic carbon, (17) mat dissolved organic matter, (18) mat particulate organic matter (nonliving), (19) mat dissolved oxygen, (20) mat volume, and (21) lake volume (living part only). Parametric equations, which are those for environmental variables influencing the biomasses and nutrients of interest, are: (1) boron concentrations in the water column, (2) boron concentration in the mat, (3) salt concentration in the water column, (4) salt concentration in the mat, (5) glacier and mountain blockage of sunlight, (6) daily/seasonal sunlight intensity, (7) water column temperature, (8) mat temperature. (9) water column pH. (10) mat pH. (11) freezing/ melting of lake ice, (12) meltwater input of algae (tychoplankton). (13) meltwater input of bacteria, (14) meltwater input of yeasts, (15) meltwater input (freshwater), (16) meltwater input of inorganic carbon, (17) meltwater input of dissolved organic matter, (18) meltwater input of particulate organic matter, (19) meltwater input of phosphorus, (20) meltwater input of inorganic nitrogen, and (21) meltwater input of dissolved oxygen. Sensitivity studies have been conducted to examine the depth of various concepts in the submodels. Such submodels 23
WATER (.ULUMN ALGAE L6 15 14 13 1 11 10 9 B 7 6 5, 4, 3, 2 I 0
I 40
I GAYS 80
WATER COLUMN ALGAE 161 15 I 14 I 13 1 121 11 1 10 1 91 81 7! 61 51 41 31 2 I 1 1 240
SUNLIGHT INTNS. L PER DY
SCALE = 3.18E-02
16 15 14 13 12 11 10 9, 8 7 61 51 41 31 2 11
**** *******A*******
I 120
I 160
SCALE
I 200
240
*
*
*
*
*
I 40
I DAYS 80
SUNLIGHT INTNS. I PER DY
0.14E-02
161 15 1 14 1 13 1
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*
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12!
11 I 10 I 91 81
71
61 51 41 31 2 I 1 I *******a*****ss **
,
I 280
I DAYS 320
I 360
I 400
I 440
I 480
I 240
SCALE = 0.35E 02
I 280
I 120
I 160
200
e40
SCALE = 0.35E 02 * ** * * * * * * * * * * *
*
* ****
DAYS 1 323
*
**** I 360
1 400
440
480
Figure 2. Examples of Lake Bonney mathematical model computer output. 2A. 480 day prediction of phytoplankton algal biomass for East Lake lobe (g/m 3 = y axis value x 0.18x10 2 and = y axis value x 0.14x10 2 , respectively). 2B. Sunlight intensity over Lake Bonney (langleys per day = y axis value x 0.35x102).
include (1) the effect of boron toxicity on algal growth, (2) the sink effect of the mat in nutrient uptake from the water column and (3) primary production as a function of light intensity, nitrogen, phosphorus, inorganic carbon, dissolved organic matter, boron concentration, and salinity. Although our field studies at Lake Bonney have covered only the austral summer, our model has been expanded to include the winter and day-by-day predictions for a period of more than 2 years. Other programs cover periods of 120 and 480 days. An example of the computer output is illustrated in figure 2A, which shows phytoplankton biomass. Figure 2B illustrates graphically the parametric equation for sunlight. Having a total lake ecosystem model allows one to order biological concepts in terms of their individual contribution to the lake as a whole. It is also a useful tool in exploring the environmental impact of perturbations on the lake. While this model would require major alteration for typical dimictic lakes or impoundments in exorheic regions, such as most of North America, South America, and New Zealand, the model could be adapted to other similar meromictic lakes with only minor changes in coefficients and parametric equations. We gratefully acknowledge support of National Science Foundation grant GV-351 71 and members of the 1976-1977 Lake Bonney field team: T. Allnutt, B. Bishop, D. Brown, J . Crate, L. Heiskell, Jr., W. Thompson, D. Wendt, and S. Wendt. 24
Baseline microbiological data for soils of the Dufek Massif B.C. PARKER, A.B. FORD,* T. ALLNUTT, B. BISHOP, and S. WENDT
Virginia Polytechnic Institute & State University Blacksburg, Virginia 24061
Cameron and Ford (1974) report the first baseline microbiological data for soils of the Pensacola Mountains. Especially noteworthy are their findings that few organisms and low species diversities are associated with these relatively remote and pristine residual soils, thereby resembling the earlier results from undisturbed sites in the dry valleys of Victoria Land. We report here a preliminary assessment of this earlier study using 23 aseptically collected soil samples from the Dufek Massif, primarily between 82139'S. 53°40'W. and 82°30'S. 51°48'W. Collections were made 1-20 December 1976 and brought to McMurdo Station within 2 weeks for immediate pro8 Alaskan Geology Branch, U.S. Geological Survey, Menlo Park, California 94025.
ANTARCTIC JOURNAL
—Wood
Ecosystem studies and mathematical model for Lake Bonney, Taylor Valley, southern Victoria Land LEONARD W. HOWELL, JR., RICHARD G. KRUTCHKOFF, and BRUCE C. PARKER
Virginia Polytechnic Institute and State Unwersity Blacksburg, Virginia 24061 The fifth and final austral summer of our study of the Lake Bonney ecosystem pursuant to a mathematical model was undertaken from November 1976 to January 1977. Measurements throughout the season included dissolved 02, pH, sulfates, NH,,-N, NO 3 -N, NO 2 -N, primary productivity, algal counts, temperature, alkalinity, and PO 4 -P. Increasing emphasis was given to assessment of glacial meltwater input to the lake, inorganic nitrogen and orthophosphorus composition of the meltwater and the icecemented permafrost, and a new investigation of carbon-14 organic substrate uptake by the plankton microorganisms. These data will be reported subsequently following detailed analysis and interpretation. In addition, we are investigating the growth of Lake Bonney, the volume of which has more than doubled since its discovery and description by Scott's field party in 1903. The lake's growth in recent years is emphasized by the necessity to abandon the hut in January 1977 when the water level reached its foundation (figure 1). This hut was erected in 1962 and was several meters above Lake Bonney ice at that time. The remainder of this report describes the mathematical model, now nearly complete and to our knowledge the first such model for an arheic, meromictic lake. Our modeling approach for the Lake Bonney ecosystem has been to employ three categories of information to develop a model as a tool for exploring interactions between various lake organisms and their environments. These three categories are (1) real data or measurements taken at Lake Bonney (e.g., nutrient levels, productivity rates), (2) real data or measurements from other aquatic ecosystems (e.g., nutrient uptake rates, cell composition) and (3) intuitive guesses (e.g., death rates, consumption rates). The Lake Bonney model is deterministic and consists of 21 simultaneous differential equations, 21 parametric equations, 42 submodels, and 180 coefficients. We have written a FORTRAN program that solves these equations numerically, giving the solutions graphically and/or in tabular form. Four programs permit a variety of input-output options. October 1977
Figure 1. Lake Bonney hut (built 1962) and analytical chemistry lab (built 1971) in early January 1977, showing lake water surrounding the hut and at a level nearly touching the foundation. Each program calls each of the subprograms, and many of the subprograms call each other as they run on the IBM 370/158 computer. Other important features of the model are mass-balance, which checks the consistency of the equations, and a confidence interval submodel that allows for confidence intervals in prediction. Differential equations used in our model consist of derivatives of biomass and nutrient (or other variable) concentrations with respect to time, as follows: (1) suspended (plankton) algae, (2) suspended (plankton) bacteria, (3) suspended (plankton) yeasts, (4) water column phosphorus, (5) water column inorganic nitrogen, (6) water column inorganic carbon, (7) water column particulate organic matter (nonliving), (8) water column dissolved organic matter, (9) water column dissolved oxygen, (10) mat algae (referring to benthic attached felts), (11) mat yeasts, (12) mat bacteria, (13) mat consumers (referring to ciliates, rotifers, tardigrades and nematodes in mats and which are not found in the plankton), (14) mat inorganic nitrogen, (15) mat phosphorus, (16) mat inorganic carbon, (17) mat dissolved organic matter, (18) mat particulate organic matter (nonliving), (19) mat dissolved oxygen, (20) mat volume, and (21) lake volume (living part only). Parametric equations, which are those for environmental variables influencing the biomasses and nutrients of interest, are: (1) boron concentrations in the water column, (2) boron concentration in the mat, (3) salt concentration in the water column, (4) salt concentration in the mat, (5) glacier and mountain blockage of sunlight, (6) daily/seasonal sunlight intensity, (7) water column temperature, (8) mat temperature. (9) water column pH. (10) mat pH. (11) freezing/ melting of lake ice, (12) meltwater input of algae (tychoplankton). (13) meltwater input of bacteria, (14) meltwater input of yeasts, (15) meltwater input (freshwater), (16) meltwater input of inorganic carbon, (17) meltwater input of dissolved organic matter, (18) meltwater input of particulate organic matter, (19) meltwater input of phosphorus, (20) meltwater input of inorganic nitrogen, and (21) meltwater input of dissolved oxygen. Sensitivity studies have been conducted to examine the depth of various concepts in the submodels. Such submodels 23
WATER (.ULUMN ALGAE L6 15 14 13 1 11 10 9 B 7 6 5, 4, 3, 2 I 0
I 40
I GAYS 80
WATER COLUMN ALGAE 161 15 I 14 I 13 1 121 11 1 10 1 91 81 7! 61 51 41 31 2 I 1 1 240
SUNLIGHT INTNS. L PER DY
SCALE = 3.18E-02
16 15 14 13 12 11 10 9, 8 7 61 51 41 31 2 11
**** *******A*******
I 120
I 160
SCALE
I 200
240
*
*
*
*
*
I 40
I DAYS 80
SUNLIGHT INTNS. I PER DY
0.14E-02
161 15 1 14 1 13 1
**** ****t
0
*
***** v**s*.
12!
11 I 10 I 91 81
71
61 51 41 31 2 I 1 I *******a*****ss **
,
I 280
I DAYS 320
I 360
I 400
I 440
I 480
I 240
SCALE = 0.35E 02
I 280
I 120
I 160
200
e40
SCALE = 0.35E 02 * ** * * * * * * * * * * *
*
* ****
DAYS 1 323
*
**** I 360
1 400
440
480
Figure 2. Examples of Lake Bonney mathematical model computer output. 2A. 480 day prediction of phytoplankton algal biomass for East Lake lobe (g/m 3 = y axis value x 0.18x10 2 and = y axis value x 0.14x10 2 , respectively). 2B. Sunlight intensity over Lake Bonney (langleys per day = y axis value x 0.35x102).
include (1) the effect of boron toxicity on algal growth, (2) the sink effect of the mat in nutrient uptake from the water column and (3) primary production as a function of light intensity, nitrogen, phosphorus, inorganic carbon, dissolved organic matter, boron concentration, and salinity. Although our field studies at Lake Bonney have covered only the austral summer, our model has been expanded to include the winter and day-by-day predictions for a period of more than 2 years. Other programs cover periods of 120 and 480 days. An example of the computer output is illustrated in figure 2A, which shows phytoplankton biomass. Figure 2B illustrates graphically the parametric equation for sunlight. Having a total lake ecosystem model allows one to order biological concepts in terms of their individual contribution to the lake as a whole. It is also a useful tool in exploring the environmental impact of perturbations on the lake. While this model would require major alteration for typical dimictic lakes or impoundments in exorheic regions, such as most of North America, South America, and New Zealand, the model could be adapted to other similar meromictic lakes with only minor changes in coefficients and parametric equations. We gratefully acknowledge support of National Science Foundation grant GV-351 71 and members of the 1976-1977 Lake Bonney field team: T. Allnutt, B. Bishop, D. Brown, J . Crate, L. Heiskell, Jr., W. Thompson, D. Wendt, and S. Wendt. 24
Baseline microbiological data for soils of the Dufek Massif B.C. PARKER, A.B. FORD,* T. ALLNUTT, B. BISHOP, and S. WENDT
Virginia Polytechnic Institute & State University Blacksburg, Virginia 24061
Cameron and Ford (1974) report the first baseline microbiological data for soils of the Pensacola Mountains. Especially noteworthy are their findings that few organisms and low species diversities are associated with these relatively remote and pristine residual soils, thereby resembling the earlier results from undisturbed sites in the dry valleys of Victoria Land. We report here a preliminary assessment of this earlier study using 23 aseptically collected soil samples from the Dufek Massif, primarily between 82139'S. 53°40'W. and 82°30'S. 51°48'W. Collections were made 1-20 December 1976 and brought to McMurdo Station within 2 weeks for immediate pro8 Alaskan Geology Branch, U.S. Geological Survey, Menlo Park, California 94025.
ANTARCTIC JOURNAL
