DTIC ADA441285: Water-Quality Parameters and Benthic Algal Communities at Selected Streams in Minnesota, August 2000-Study Design, Methods, and Data

59 Pages·1.8 MB·English

by  Defense Technical Information Center

Water-Quality Parameters and Benthic
Algal Communities at Selected Streams in
Minnesota, August 2000—Study Design,
Methods, and Data
By K.E. Lee
Open-File Report 02-43
Prepared in cooperation with the Minnesota Pollution Control Agency, Minnesota Department of Natural Resources, and
the U.S. Environmental Protection Agency
Report Documentation Page Form Approved
OMB No. 0704-0188
Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,
including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington
VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it

does not display a currently valid OMB control number.
1. REPORT DATE 2. REPORT TYPE 3. DATES COVERED
2002 N/A -
4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER
Water-Quality Parameters and Benthic Algal Communities at Selected
5b. GRANT NUMBER
Streams in Minnesota, August 2000-Study Design, Methods, and Data
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
U.S. Department of the Interior 1849 C. Street, NW Washington, DC REPORT NUMBER
20240
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)
11. SPONSOR/MONITOR’S REPORT
NUMBER(S)
12. DISTRIBUTION/AVAILABILITY STATEMENT
Approved for public release, distribution unlimited
13. SUPPLEMENTARY NOTES
14. ABSTRACT
15. SUBJECT TERMS
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF
ABSTRACT OF PAGES RESPONSIBLE PERSON

a. REPORT b. ABSTRACT c. THIS PAGE SAR 58
unclassified unclassified unclassified
Standard Form 298 (Rev. 8-98)
Prescribed by ANSI Std Z39-18
U.S. DEPARTMENT OF THE INTERIOR
Gale A. Norton, Secretary
U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director
Use of brand names in this report is for identification purposes only and does not
constitute endorsement by the U.S. Geological Survey.
Mound View, Minnesota, 2002
For additional information write to:
U.S. Geological Survey
District Chief
2280 Woodale Drive
Mounds View, MN 55112
Copies of this report can be purchased from:
U.S. Geological Survey
Branch of Information Services
Box 25286, MS 517
Federal Center
Denver, CO 80225
Information regarding the USGS is available on the Internet via the World Wide Web.
You may connect to the USGS Home Page using the Universal Resource Locator (URL) at
http://wwwrvares.er.usgs.gov.
You may also connect to the Minnesota District Home Page at
http://mn.water.usgs.gov/.
For more information on all USGS reports and
products (including maps, images, and computerized data), call 1-888-ASK-USGS
Open-File Report 02–43
CONTENTS
Abstract.................................................................................................................................................................................1
Introduction...........................................................................................................................................................................1
Purpose and scope....................................................................................................................................................................................2
Study design and methods....................................................................................................................................................2
Precipitation data.....................................................................................................................................................................................4
Hydrologic Data........................................................................................................................................................................................4
Diurnal water-quality measurements.........................................................................................................................................................4
Stream productivity and respiration estimates..........................................................................................................................................4
Benthic algae collection and identification................................................................................................................................................4
Hydrologic characterization..................................................................................................................................................5
Parameters.............................................................................................................................................................................5
Water quality............................................................................................................................................................................................5
Primary production and respiration...........................................................................................................................................................5
Benthic Algae...........................................................................................................................................................................................5
References...........................................................................................................................................................................19
Supplemental information...................................................................................................................................................21
FIGURES
Figure 1. Maps showing the location of sampling sites where diurnal water-quality measurements and benthic
algae samples were collected during August 2000, and ecoregions in the study area..........................................3
Figures 2-14: Graphs showing:
2. Daily-mean discharge during 2000, and long-term mean-daily discharge during June, July and August at
U.S. Geological Survey gaging stations near sampling sites..............................................................................6
3. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Crow Wing River near Nimrod, Minnesota........................................................................................................7
4. Specific conductance, water temperature, dissolved oxygen, and percent oxygen saturation of the
Crow Wing River near Staples, Minnesota.........................................................................................................8
5. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Mississippi River near Aitkin, Minnesota..........................................................................................................9
6. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Mississippi River near Anoka, Minnesota........................................................................................................10
7. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Rum River near Isanti, Minnesota....................................................................................................................11
8. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Rum River near St. Francis, Minnesota............................................................................................................12
9. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Crow River near Rockford, Minnesota.............................................................................................................13
10. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Crow River near Dayton, Minnesota................................................................................................................14
11. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Blue Earth River West of Winnebago, Minnesota............................................................................................15
12. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Blue Earth River near Amboy, Minnesota........................................................................................................16
13. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
Red River near Brushvale, Minnesota..............................................................................................................17
iii
FIGURES--CONTINUED
14. Specific conductance, pH, water temperature, dissolved oxygen, and percent oxygen saturation of the
RedRiver near Moorhead, Minnesota...............................................................................................................18
TABLES
1. Drainage area, latitude and longitude, land use, ecoregion for 12 sites located on six streams in Minnesota where
diurnal water-quality measurements and benthic algae samples were collected during August 2000................21
2. Site conditions at time of benthic algae collection and dates for diurnal water-quality measurements for 12
sites located on six Minnesota streams sampled during August 2000.................................................................22
3. Median specific conductance, pH, water temperature, dissolved oxygen, and percent dissolved oxygen saturation
for 12 sites located on six streams in Minnesota during August 2000................................................................22
4. Estimates of net community primary production and respiration for 12 sites located on six streams sampled
during August 2000.............................................................................................................................................23
5. Chlorophyll-a content of benthic algae collected from rock and wood substrate from 12 sites located on six
streams in Minnesota during August 2000..........................................................................................................23
6. Total biovolume and density of benthic algae collected from rock and wood substrate from 12 sites located
on six streams in Minnesota during August 2000.............................................................................................. 24
7. Relative biovolume of benthic algae collected from rock substrate at 12 sites located on six streams in
Minnesota during August 2000...........................................................................................................................25
8. Relative biovolume of benthic algae collected from wood substrate at 12 sites located on six streams in
Minnesota during August 2000...........................................................................................................................34
9. Relative density of benthic algae collected from rock substrate at 12 sites located on six |streams in
Minnesota during August 2000...........................................................................................................................41
10. Relative density of benthic algae collected from wood substrate at 12 sites located on six streams in
Minnesota during August 2000...........................................................................................................................48
CONVERSION FACTORS AND ABBREVIATIONS
Multiply metric unit By To obtain inch-pound unit
inches (in.) 2.54 centimeters
square mile (mi2) 2.590 square kilometer
cubic foot per second (ft3/s) 0.02832 cubic meter per second
degrees Fahrenheit (°F) (Temp. oF - 32) / 1.8 degrees Celsius (°C)
Concentrations are given milligrams per milliliter (mg/L). A milligram is one thousandth of a gram. Electrical conductivity is measured
as specific electrical conductance in units of microsiemens per centimeter (µS/cm) at 25 degrees Celsius.
iv
Water-Quality Parameters and Benthic
Algal Communities at Selected Streams in
Minnesota, August 2000—Study Design, Methods,
and Data
By Kathy E. Lee
ABSTRACT composition and chlorophyll-a content, and primary
productivity at 12 stream sites on 6 streams in Minnesota
Water-quality measurements and benthic algal samples
during August 2000. Specific conductance, pH, water
were measured or collected from select Minnesota streams
temperature, dissolved oxygen concentrations and percent
as part of a multiagency (Minnesota Pollution Control
dissolved oxygen saturation measurements were made
Agency, Minnesota Department of Natural Resources,
with submersible data recorders at 30 minute intervals
U.S. Environmental Protection Agency, and U.S. Geologi-
for a period of 3-6 days during August 2000. Benthic
cal Survey) study. The goal of the multiagency study was
algae collected from wood and rock substrate were identi-
to identify quantifiable thresholds of water-quality impair-
fied and enumerated. Biovolume (volume of algal cells
ment and establish quantifiable indicators of nutrient
per unit area), density (number of cells per unit area),
enrichment for medium to high-order streams.
and chlorophyll-a content from benthic algae were deter-
This report describes the study design, sampling
mined. These data can be used as part of the multiagency
methods, and summarizes the physical, chemical, and
study to develop an understanding of the relations among
benthic algal data for a component of the multiagency
nutrient concentrations, algal abundance, algal community
study that was designed to document diurnal water-quality
composition, and primary production and respiration pro-
measurements (specific conductance, pH, water tempera-
cesses in rivers of differing ecoregions in Minnesota.
ture, and dissolved oxygen), benthic algal community
INTRODUCTION Nutrients are essential for animal and necessary to develop locally-relevant
plant growth; however, elevated nutri- TMDLs.
The presence of contaminants,
ent concentrations are potentially
and physical or chemical degradation Abiotic factors influencing water
toxic to humans and wildlife and can
affects 36 percent of surveyed river chemistry include climate, geology,
stimulate excessive algal and plant
miles in the United States (U.S. Envi- land use and land cover, soil type,
growth (Wetzel, 1983).
ronmental Protection Agency,1998). topography, and hydrologic character-
Historically, water-resource manage- istics. Biotic factors including
The U.S. Environmental Protec-
ment efforts focused on point sources instream plant and animal metabolism
tion Agency (USEPA) total maximum
of contaminants such as industrial and also influence water chemistry. The
daily load (TMDL) rules are part of
wastewater treatment discharges. The most influential biotic factor affecting
the Clean Water Act section 303(d)
focus has shifted more recently to the nutrient concentrations and other con-
requiring each state to identify
influence of nonpoint source runoff stituents in streams is algal commu-
streams that are not in compliance
on water quality (Boyd, 2000). Non- nity uptake and metabolism (Stumm
with multiple water quality standards
point source contaminants such as and Morgan, 1996). Algal communi-
including nutrient concentrations
nutrients (nitrogen and phosphorus) ties in streams are comprised of phy-
(U.S. Environmental Protection
enter streams through runoff from the toplankton (algae entrained in water
land surface during snow-melt, spring Agency, 1998). Both abiotic and column) and benthic algae that reside
and summer precipitation, from biotic factors and interactions on submerged substrates including
ground-water discharge, or from tile between them influence nutrient con- woody debris (epidendiric), rock
drains and storm sewers (Osborne and centrations, and a greater understand- (epilithic), and macrophytes (epi-
Wiley, 1988; Wiley and others, 1990). ing of these factors and interactions is phytic). Benthic algae include
1
attached forms and phytoplankton that fish. Primary productivity (the rate of were used as the major spatial strata
have settled onto the bottom of formation of organic material over because they are areas with common
streams in quiescent areas. some time period) is an indicator of ecological settings that have relatively
Benthic algal photosynthesis and the health of a stream (Wetzel, 1983) homogenous features including cli-
respiration processes influence nutri- because oxygen and carbon sources mate, geology, land use and land
ent flux (Newbold and others, 1982; form the base of the food chain in cover, soil type, and physiography
Stumm and Morgan, 1996) and other aquatic systems. Benthic algae are (Fandrei and others, 1988; Omernik
water-quality parameters such as spe- important primary producers in and Gallant, 1988). The goal of the
cific conductance, pH, dissolved oxy- streams (Stevenson and others, 1996) multiagency study is to identify quan-
gen and carbon dioxide. During and may be the primary source in tifiable thresholds of water-quality
photosynthesis, algae utilize energy mid-size streams (Vanote and others, impairment and establish quantifiable
from sunlight, take in nutrients and 1980). indicators of nutrient enrichment for
carbon to produce carbohydrates Establishment of water-quality medium to high-order streams.
(needed in algal cell growth), and pro- standards for nutrients has not histori-
STUDY DESIGN AND METHODS
duce oxygen as characterized by this cally been based on the complex inter-
stoichiometry (Stumm and Morgan, actions of abiotic and biotic factors.
Site selection criteria included
1996): The information generated in this and
drainage area, ecoregion type, and
106CO2 + 16NO3- + HPO42- + 122 H2O + 18 H+ concurrent studies will provide an presence of a streamflow gaging sta-
opportunity to develop statistical rela-
(+ Trace Elements and Energy) tion. The 12 sites on six rivers
C H O N P + 138 O sunlight tions between chemical factors (nutri-
106 263 110 16 1 2 selected for this study had drainage
(algal protoplasm) ent concentrations) and biological
areas greater than 1,000 mi2. These
Changes in pH, dissolved oxy- factors (primary production processes
sites were located within four differ-
gen, and nutrient concentrations occur or algal community composition) that
ent ecoregions at or near U.S. Geolog-
during this process. Dissolved oxygen can be used by managers in stream-
ical Survey (USGS) or other
and pH concentrations increase, and water-quality-criteria development.
streamflow gaging stations (fig. 1,
dissolved nutrient concentrations
table 1, at the back of the report). Riv-
Purpose and Scope
decrease as algae increase photosyn-
ers that were representative of each
thetic activity during the day. The
The report describes the study ecoregion were selected. Two sites
uptake of carbon dioxide during day-
design, methods, and provides were sampled on each river to allow
light accompanied by the uptake of
selected water-quality parameters and upstream and downstream compari-
nitrate (NO -) or phosphate (HPO -)
3 4 benthic algal data for 12 sites located sons of nutrient flux in a concurrent
and H+ ions results in a pH increase
on six Minnesota streams sampled study. Each site has a designated site
due to the remaining OH- ions. Dis-
during August 2000. The purposes of identifier. The site identifier is com-
solved oxygen and pH decrease dur-
the study were to document specific prised of two or three letters corre-
ing the night as photosynthesis ceases
conductance, pH, water temperature, sponding to the river name followed
and aquatic animals continue to con-
dissolved oxygen (DO), benthic algal by numbers that correspond to the
sume oxygen and respire. The
abundance, community composition, river mile near the site location. For
reduced dissolved oxygen concentra-
and chlorophyll-a content, and to example, the Crow Wing River near
tions and pH at night are also aug-
provide estimates of net primary pro-
Nimrod, Minnesota (CWR-72.3) is
mented by microbial bacterial
ductivity and respiration at each site.
located 72.3 miles upstream of the
decomposition of biota to NO -. Bio-
3 This study is one component of a mul- confluence of the Crow Wing and the
logical oxygen demand (BOD) is a
tiagency (Minnesota Pollution Con-
Mississippi Rivers.
measurement of the amount of oxygen
trol Agency, Minnesota Department
required to stabilize the demands for of Natural Resources, U.S. Environ- August was selected as the time
oxygen during the microbial decom- mental Protection Agency, and U.S. frame for this study because the
position of organic matter (Reid and Geological Survey) study designed to objective was to determine water
Wood, 1976). develop an understanding of the rela- quality and algal characteristics dur-
In addition to their roles in chem- tions among nutrient concentrations, ing low to medium flow and to mini-
ical modulation, algae provide a algal abundance, algal composition, mize the likelihood of runoff.
source of oxygen and carbon for pri- and primary production and respira- Precipitation generally is less frequent
mary and secondary consumers such tion processes in rivers of differing during late summer and rainfall events
as aquatic macroinvertebrates and ecoregions in Minnesota. Ecoregions usually produce less runoff, because
2
100° 98° 96° 94° 92° 90°
0 25 50 75 100MILES
LLLSSSaaattteeekkkllleeelllaaa CCAANNAADDAA 49°
49° 0 25 50 75 100KILOMETERS
Base from U.S. Geological Survey
Digital data, 1:100,000, 1993
U.S. Albers projection.
EEEaaasssttt 48°
48° GGGrrraaannndddFFFooorrrkkksss
GGrraannddFFoorrkkss
NNNOOORRRTTTHHH
DDDAAAKKKOOOTTTAAA
BBeemmiiddjjii HHiibbbbiinngg Lake Superior
GGGrrraaannnddd 47°
47° RRRaaapppiiidddsss
12 MMIINNNNEESSOOTTAA DDuulluutthh
FFaarrggoo MMoooorrhheeaadd NNiimmrroodd
1 3 AAiittkkiinn MMIICCHHIIGGAANN
11
SSttaapplleess BBrraaiinneerrdd
BBrruusshhvvaallee 2
WWaahhppeennttoonn FFeerrgguussFFaallllss 46°
46°
SSaaiinntt CClloouudd SSSaaaiiinnnttt 5
FFFrrraaannn6ccciiisss IIssaannttii
DDaayyttoonn AAnnookkaa WWIISSCCOONNSSIINN
RRoocckkffoorrdd8 4 45°
45° 7
MMiinnnneeaappoolliiss
SSSOOOUUUTTTHHH SSSaaaiiinnnttt
PPPaaauuulll
DDDAAAKKKOOOTTTAAA
MMaarrsshhaallll RReeddWWiinngg
44° RRaapp1ii0ddaann MMaannkkaattoo OOwwaattoonnnnaa RRoocchheesstteerr 44°
AAmmbbooyy
9
WWiinnnneebbaaggoo AAllbbeerrtt LLeeaa
IIOOWWAA
100° 98° 96° 94° 92° 90°
100° 98° 96° 94° 92° 90° EXPLANATION
7 Sampling site (with site
CANADA 0 25 50 75 100 MILES 49°
49° identifier)
0 25 50 75100 KILOMETERS
Source: Omernik
and Galant, 1988
49
48°
48°
NORTH 48
DAKOTA
50 47°
47°
42
MINNESOTA
ECOREGIONS
46°
46° 46 (42) NW Glaciated plains
50
(43) NW Great plains
51
WISCONSIN (45) Piedmont
45° 43 45° (46) N. Glaciated Plains
(47) W. Corn belt Plains
SOUTH
(48) Lake Agassiz Plain
DAKOTA 51 (49) N. Minnesota Wetlands
45 44° (50) N. Lakes and Forest
44°
47 (51) N. Cen. Hardwood Forest
52 (52) Driftless area
IOWA 53 (53) SE Wisconsin till plains
100° 98° 96° 94° 92° 90°
Figure 1. The location of sampling sites where diurnal water-quality measurements and benthic algae samples were collected during
August 2000, and ecoregions in the study area.
3
of reduced soil-moisture and exten- vals over a period of 3-6 days using of benthic algae sample collection
sive vegetative cover on cropland submersible data recorders (HydoLab (table 2). Benthic algae were collected
areas. In an extensive study area, such Data Sonde units). The probes were from both wood (epidendric) and rock
as Minnesota, the amount of time positioned in the euphotic zone in an (epilithic) substrate at each site and
required to adequately sample area of streamflow of at least 1 ft3/s. processed separately. Benthic algae
selected streams increases the proba- The probes were calibrated according samples were collected in accordance
bility that streamflow will be unsteady
to manufacturers specifications before with the USGS National Water Qual-
in some streams because of precipita-
installation at a site and following ity-Assessment Program (NAWQA)
tion-induced runoff.
retrieval. New batteries and DO sen- algal sampling protocols (Porter and
sor membranes were installed prior to others, 1993).
Precipitation Data
each deployment.
Epidendric samples were col-
Daily precipitation data were lected from submerged woody debris
Stream Productivity and
obtained to provide an environmental that was in the euphotic zone of the
context for diurnal water-quality mea- Respiration Estimates stream. Epidendric samples were col-
surements and benthic algal data. lected from 10 locations in each
Stream productivity and respira-
Daily precipitation amounts for stream reach. Snags were gently
tion were estimated using DO concen-
August 2000 were obtained from the removed from the water to minimize
trations over diurnal periods (table 2,
Minnesota Department of Natural disturbance of the algal community; a
at the back of the report). Chloro-
Resources Climatology website 3–4 inch cylindrical section was cut
phyll-a content in benthic algae was
(http://www.climate.umn.edu). Daily from each snag with lopping shears;
also measured as an alternate measure
rainfall data were obtained for the and the snag sections were retained in
of primary production. Net productiv-
weather station closest to the stream a plastic bag prior to processing. After
ity and respiration estimates were algae were removed from the snag
sampling site.
quantified according to Sorrenson and sections, the length and diameter of
Hydrologic Data others (1999). Briefly, productivity each section was measured, and the
estimates were determined by calcu- surface area of each snag segment was
Daily-mean streamflow (the mean lating the slope of the DO concentra- calculated.
discharge for a particular day) for tions between 10 am and 3 pm. This
Epilithic samples were collected
June through August 2000 was time period was used because the
from submerged rocks located in the
obtained for USGS stream gages that rapid rates of change in DO were lin-
euphotic zone. Approximately 10 dif-
were located near sampling sites ear. The estimates define the net rate
ferent rocks, which were carefully
(table 1). The daily-mean streamflow of oxygen accrual in milligrams of
removed and placed in a container
provides information about near-term oxygen per Liter per hour (mg
with benthic algal growth facing up.
conditions that may influence physi- O /L/hr), which is equivalent to grams
2 After algae were removed from each
cal, chemical and biological charac- of O per cubic meter per hour (g
2 rock a foil template was created to
teristics. The long term mean-daily O /m3/hr). Net community respiration
2 cover the section of the rock covered
streamflow (mean for a particular day was quantified by calculating the
with algae. This foil template was
over the period of record) was also slope of the DO concentrations
retained and measured to determine
computed for each site and provides a between midnight and 6 a.m. Esti-
surface area.
benchmark to determine if stream- mates of productivity and respiration
Samples were processed simi-
flows during the study period were do not account for rates of oxygen dif-
larly as described below. Algae were
generally higher or lower than average fusion that are a function of water
removed from each snag section or
conditions. These hydrologic data temperature and the difference in oxy-
rock using a stiff-bristled brush and
were obtained from the USGS gen saturation between water and air
de-ionized water from a rinse bottle.
National Water Information System’s (Odum, 1956).
The algal suspension from each sam-
Automated Data Processing System.
Benthic Algae Collection and ple (epilithic and epidendric samples
Diurnal Water-Quality were processed separately) was
Identification
washed into a small, plastic process-
Measurements
Benthic algae were collected from ing pan. Samples were processed until
Measurements of specific conduc- each site during the period of diurnal about 50 to 100 mL of water had
tance, pH, water temperature, and DO water-quality measurements. Site con- accumulated in the processing pan.
were recorded at 30 minute inter- ditions were characterized at the time The combined algal-water suspension
4
was homogenized for approximately lection periods at the following sites: acceptable. It is not possible to deter-
30 seconds. The homogenate was split Crow Wing River near Nimrod and mine if the abrupt change in specific
into subsamples for determinations of Staples (CWR-72.3 and 35.5, respec- conductance was a result of runoff
chlorophyll-a (5mL), and identifica- tively); Mississippi River near Aitkin from precipitation or probe malfunc-
tion (60 mL). The homogenate from (UM-872); Crow River at Rockford tion.
one sample (Mississippi River near (CR-23); Blue Earth River near Win-
Anoka, Minnesota) was split into nebago and Amboy (BE-73.2 and 54, Primary Production and
three portions to determine variability respectively); and Red River near
Respiration
in algal samples. Brushvale and Moorhead (RED-536
Chlorophyll-a samples were fil- and 452, respectively). Net community primary produc-
tered through a 0.47 mm glass fiber tion and respiration estimates are
PARAMETERS
filter with 5 pounds of pressure per shown in table 4, at the back of the
square inch. The filter was placed in WATER QUALITY report. Potential factors influencing
rates of primary production and respi-
foil inside of a petri dish and placed
Table 3, at the back of the report, ration include the density of benthic
on dry ice prior to analysis at the Min-
shows summary statistics for diurnal algae, aquatic macrophytes, abun-
nesota Department of Health Labora-
measurements of specific conduc- dance of phytoplankton, solar inten-
tory. Taxonomic samples were placed
tance, pH, water temperature, dis- sity/cloud cover, precipitation, water
in a glass bottle with 1 percent glut-
solved oxygen and pecent oxygen temperature, hydrologic characteris-
araldehyde as a preservative and kept
saturation at each site. Figures 3-14 tics, the density of aquatic insects that
in a refrigerated low light environ-
show specific conductance, pH, water graze on algae, microbial community
ment prior to shipment to Phycotech
temperature and dissolved oxygen for composition, and density of aquatic
in St. Joseph, Michigan for analyses.
each site. The y-axis scale for a organisms utilizing dissolved oxy-
Identification of algal taxa were
gen. Net community primary produc-
selected constituent may not be simi-
accomplished by Phycotech personnel
tion varied from 0.03 to 1.10
lar in figures 3-14 due to differences
using methods modified from Crump- g/O /m3/hr among all streams. Net
in data magnitude which would 2
ton (1987). HPMA (2-hydroxypropyl community respiration estimates var-
obscure the patterns of the water-qual-
methacrylate) was used in sample ied from 0 to 1.09 g/O /m3/hr. Chlo-
ity parameters within each site. 2
mounting which provides an optically rophyll-a content varied from 2.1 to
clear background while permanently In general, dissolved oxygen con- 150 mg/m2 among all samples (table
infiltrating and preserving the sample centrations, dissolved oxygen percent 5, at the back of the report). Net com-
for archival purposes. saturation, pH and temperature val- munity primary production and respi-
ration rates and chlorophyll-a contents
ues increased, and specific conduc-
HYDROLOGIC
observed for streams in this study
tance values decreased during
CHARACTERIZATION were similar to those observed for 72
daylight hours. These trends were
agricultural streams in the upper mid-
reversed during nighttime period. Dis-
The hydrologic conditions during west (Sorenson and others, 1999).
solved oxygen concentrations went
June and July 2000 prior to sampling
below the state standard of 5.0 mg/L
were characterized by variable stream
Benthic Algae
at the Mississippi River at Anoka (fig.
discharge in response to storm events.
6).
Daily-mean stream discharges during
Community composition is repre-
June and July 2000 were character-
The pH values for the Crow sented by both biovolume (volume of
ized by one or more storm events of
Wing River near Staples (fig. 4) is algal cells per unit area) and density
varying magnitudes (fig.2).
missing due to probe malfunction. (number of cells per unit area) of taxa.
Hydrologic conditions during the Specific conductance at the Red River Biovolume is closely linked with
August sampling period were stable near Brushvale (fig. 13) is problem- observed thickness of algae on a sub-
and streamflows were below the long- atic due to the non-gradual change in strate. Bivolume provides an estimate
term mean flows at most sites except specific conductance after the rain of biomass and represents taxa shifts
at the Red River of the North sam- storm on August 16th. An indepen- well when the size of algae are vari-
pling locations where the flow was dent measure of the specific conduc- able (Stevenson and others, 1996).
low and stable, but was greater than tance on August 15th was similar to Density estimates generally have less
the long-term mean streamflow. Pre- that recorded by the submersible data variability than biovolume, but taxa
cipitation events of approximately 0.5 sonde and the post deployment-cali- shifts may be obscured when cell
inches occurred during sampling col- bration check of the sonde was sizes are variable. Table 6, at the back
5