Stream and Lake Monitoring Protocol
SOP 10 – Lakes Field Sample Collection, v. 1.0, Page 1 of 7
Stream and Lake Monitoring Protocol
Arctic Network (ARCN), Alaska
Standard Operating Procedure (SOP) # 10
Aquatic Invertebrate Field Sampling
Version 1.0 (Lakes) (November 2007)
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Introduction
This SOP provides information on how to collect limnological information on lakes in
the National Parks units in the Arctic Network (ARCN). Laboratory analyses conducted after
sampling will follow in a subsequent SOP.
Preparation for Lakes Sampling
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(to be done the night before sampling or earlier)
1. Label all bottles that are needed for both field sampling and lab filtration, this
includes but isn’t limited to bottles for each depth for chemical analyzes,
phytoplankton, zooplankton, and benthic invertebrates.
2. Acid wash bottles for chemistry. Add 5 ml of prepared Lugols solution to each
phytoplankton and zooplankton bottle
3. Charge Hydrolab Battery-make sure to turn power save function off while
charging, but back on when finished. Also make sure you’ve downloaded
previous data.
4. Charge batteries for Garmin lake bathymetry mapping sonar.
Bottles needed (numbers depend on depths to be sampled):
Arctic Network
November, 2007
Stream and Lake Monitoring Protocol
SOP 10 – Lakes Field Sample Collection, v. 1.0, Page 2 of 7
Chemistry-
125ml Nalgene bottle with narrow mouth, Zooplankton250ml Nalgene or Polypro wide mouth clear
Algal Composite125ml Nalgene narrow mouth clear
Integrated epilimnetic water2 L amber wide mouth
Benthic invertebrates
6 250 ml Nalgene bottles
Field Sampling Checklist
1. Rafts, paddles, life jackets
2. Hydrolab & Accessories
Hydrolab Surveyor 4a
Hydrolab Datasonde 4a
Hydrolab Cable
Weighted Sensor Guard
3. Secchi disk and metered line
4. Water Column integrated sampler (7m weighted Tygon Tubing 1/4" diameter)
5. VanDorn Water sampler, messenger and metered line
6. Zooplankton net and metered line
7. Ekman grab sampler with messenger and metered line
8. Dive Buddy-depth finder (yellow, flashlight looking thing)
9. Garmin lake mapping echosounder with charged battery
10. 2L sample bottle for integrated epilimnetic sample
Ziplocks with Sampling bottles for zooplankton
Zooplankton- 6, 250ml Nalgene or Polypro wide mouth clear
Algal Composite-1, 125ml Nalgene narrow mouth clear to save
Also bring these extra items:
Spare bottles
Roll of twine
duct tape
sharpies and pencils
lable tape
Zipties/Thread
Leatherman
Small WIR Note Pad
Prior to sampling at the lake
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Arrange supplies in raft/boat, Hydrolab supplies on one side, water sampling (Van Dorn)
on the other. Secure Van Dorn and anchor to boat, make sure Hydrolab is connected to
Surveyor via threaded lock.
-
Locate desired sampling location using the dive buddy. Choose a site in a deep portion
of the lake to be the main sampling site for Hydrolab cast, Secchi, discrete depth water
column samples and one of the three samling sites for zooplankton. Verify depth to
ensure you don’t drop hydrolab or van dorn into the sediments.
Arctic Network
November, 2007
Stream and Lake Monitoring Protocol
SOP 10 – Lakes Field Sample Collection, v. 1.0, Page 3 of 7
Physical and chemical sampling using Hydrolab
Vertical profiles of temperature, dissolved oxygen, pH, specific conductivity, penetration of
photosynthetically active radiation (PAR), and chlorophyll fluorescence are measured using a
Hydrolab Surveyor and Datasonde 4a. Measurements were taken at approximately one-meter
intervals from the surface of the lake to the maximum depth (Z) of each lake.
1. Determine the “sunny” side of the boat, untangle and orient cables appropriately to lower
sonde and licor off this side. Take the time now to re-coil or untangle cords as it will be
very difficult to sort after you have played out several meters of cable.
2. Secure datasonde to hydrolab via black cable, orient cable pins in proper fashion.
Connection to datasonde must orient the larger pin with the larger port, proper orientation
is indicated by matching raised dots on the datasonde and cable. Surveyor unit is
attached to the sonde via serial port, make sure to tighten both tension screws on serial
cord.
3. Turn unit on and record the lake name, station number, date, and time.
4. Save data at each 1-m depth beginning at the surface of the lake, while the sonde is
lowered into the water column. Stop lowering the Sonde at 1 m above the lake sediment.
Collecting data on lake morphomtery
A small echosounder with GPS capabilities (Garmin xxx) is used take many discrete
locations and their associated depths. This information is collated in a Geographical Information
System to provide a bathymetric map of the lake. Data is collected in a stratified random manner
by rowing 10-15 transects across the lake. These transects are evenly spaced out along the lake.
Ideally transects would be separated by approximately 100 m.
Procedure:
1.
Attach the transducer/GPS cable to the GPS-linked, Garmin-153C
echosounder.
2.
Fix the transducer to the side of the boat such that the bottom of the transducer
is approximately 0.2 m below the lake surface and pointed straight down into
the water.
3.
Turn on the echosounder. Save the data with the lake name and year sampled.
Be sure that both latitude, longitude, and depth are being recorded and saved
by the echosounder.
Secchi Reading
General Overview: The Secchi transparency reading is a measurement of water clarity.
The Secchi diskis divided into quarters with alternating black and white sections.
Procedure:
1. Take the secchi reading from the shady side of the boat. If there is no
shade you will need to use your hand to cut down the sun glare.
2. Lower the secchi disk slowly until the white quadrants disappear, and
determine the depth to the nearest tenth of a meter.
Arctic Network
November, 2007
Stream and Lake Monitoring Protocol
SOP 10 – Lakes Field Sample Collection, v. 1.0, Page 4 of 7
3. Lower the secchi disk so it is about 0.5m below the first reading.
Slowly pull the disk up until it reappears, and determine this depth to the
nearest tenth of a meter.
4. Record both depths in field book. Average the two depths to get the
secchi depth that you will record on the data sheet.
Integrated Epilimnion Sampling.
General Overview: You are going to lower a weighted length of tygon tubing to the
bottom of the epilminion. This will give you an integrated sample of the epilimnion.
The volume of water collected dependent on depth is known or can be calculated.
Repeat this procedure until you have at least 1 liter of water in the sample bottle.
This water will be used for chlorophyll analysis, phytoplankton species identification,
and nutrient chemistry
Materials:
Integratied Sampler (weighted 7-9m tygon)
1 L brown sample bottle
Procedure:
1. Slowly lower tubing into water column, stopping at the desired depth
2. Raise tubing slowly allowing water to flow out (this effectively rinsed the tubing)
3. Slowly lower tubing again to desired depth
4. Place your thumb over the end of the tubing to “capture” the water in the tubing
5. Slowly raise the tubing, making sure not to release water
6. Allow full length of tubing (water) to drain into sample bottle
Lugol’s Solution
10 g Iodine
20 g Potassium iodine
200 mls H2O
20 ml glacial acetic acid
Discrete Depth Water Sample Collection
Use the VanDorn water sampler to collect water below the epilimnion at desired depths
for chemical analyses, zooplankton, or phytoplankton.
VanDorn Operation
1. Make certain VanDorn safety rope is attached to something secure in raft.
2. “Cock” VanDorn by grasping right plunger (not wire or ball), pulling out, and threading
wire through top receptacle while simultaneously depressing plunger-Release plunger,
bottom plunger should be armed-watch your fingers
3. Follow similar pattern with remaining plunger, except wire loop should slip over
protruded metal trigger.
4. Make sure plunger and bands aren’t tangled with rope or other parts.
5. Locate metal messenger. Orientate yourself with depth markings on rope
6. Lower VanDorn to desired depth, with a flick of your wrist drop messenger.
Arctic Network
November, 2007
Stream and Lake Monitoring Protocol
SOP 10 – Lakes Field Sample Collection, v. 1.0, Page 5 of 7
7. Pull up VanDorn, grab by handle, invert, seat bottom plunger tightly (push it with your
hand) to confirm seal to prevent all your sample water from leaking out.
8. Open top plunger, secure in typical fashion
9. Rinse sample bottle and cap a couple of times with water in VanDorn
10. Fill sample bottles with VanDorn water for chemical analyses at desired depths. Use
125 ml bottles for nutrient analyses and phytoplankton preservation, and 250 ml bottles
for zooplankton. Add 5-10 ml of Lugols preservative to phytoplankton and zooplankton
samples. When finished tightly cap both bottles, place back in depth designated ziplocktry to keep samples cool and out of sun by placing them in a small cooler.
Zooplankton Sampling
General Overview- Take 2 samples at each of three stations in the central region of the
lake. Separate sampling stations by approximately 100 m. Use the dive budy to assess depth at
each station. One station is an epilimnetic sample from approximately 5 m to the surface. Use
the temperature profile from the Hydrolab to make sure the epilimnion is at least 5 m deep. If
the epilimnion is less than 5 m deep, take the epilimnion zooplankton samples from the bottom
of the epilimnion to the surface and record the depth of water sampled. The second sample at
each station is a whole water column sample from 1 m above the sediment to the surface of the
lake. Record the detph of this sample on the bottle.
Materials
Zooplankton tow net and line
(6) 250ml wide mouth HDPEs
Bottles with Lugols preservative
Procedure
1. Familiarize yourself with net-when valve at bottom of net is open, the gray
handle is parallel with the “funnel” spout, when its closed they are perpendicular
2. Attach zoop line to stable structure in boat
3. With net open, hold by line and quickly lower/raise net in water to effectively
rinse the net.
4. Close net and slowly lower into water about 1m, may need to squeeze air out to
get it to sink effectively. Net should be stretched out with spout/end of net
positioned at the bottom.
5. Slowly lower net, insure large opening of net is always facing towards surface.
Lower to the desired depth.
6. Once desired depth is reached, raise at a moderate pace till top of net is above
the water
7. Grab net and raise and lower net (don’t resubmerge top) to rinse/wash all Zoops
into the lower portion of the net
8. Now you can grab net closer to funnel and splash water on sides to continue to
rinse zoops into funnel.
9. Tilt slightly to pore out additional water, then rinse sides with rinse bottle.
Arctic Network
November, 2007
Stream and Lake Monitoring Protocol
SOP 10 – Lakes Field Sample Collection, v. 1.0, Page 6 of 7
10. Position funnel into 250ml WM HDPE, turn valve to empty contents into bottle.
11. Rinse bottom of net/funnel with rinse bottle into sample bottle.
12. Repeat procedure the second sample at the station rinsing the net in between
samples.
Sampling for Benthic Invertebrates
Benthic invertebrates are collected from fine substrates with an Ekman Grab sampler and
from the shoreline area using a sweep net. The Grad samples are quantitative and can be
expressed as densities and biomasses per surface area of the sampler. The sweep nets provide a
qualitative estimate of species presence and absence.
1.
2.
3.
4.
5.
6.
7.
Use dive buddy to locate 3-m depth
Cock the Ekman grab sampler in open position
Rapidly lower the open sampler into the bottom sediments
Quickly drop the messenger down the taught line to close sampler
Bring the closed sampler up to the boat and hold over Ekman wash net
Open the sampler and collect the sediments
Wash the sample through the net until a small fist-sized ball of sediments and
invertebrates remain
8. Place in a 250 ml sample bottle and fill with 95% EtOH
9. To sample benthic invertebrates in near shore areas, use sweep net to make 3
5-m sweeps through the water just above the sediments in the littoral zone.
Make collection in areas with and without vegetation.
10. Place sample in 250 ml bottle and fill with 95% EtOH.
I
References
Cummins, K.W. and R.W. Merritt. 1996. Ecology and distribution of aquatic insects. In R.W.
Merritt and K.W. Cummins, eds. An introduction to the aquatic insects of North
America. 3rd ed. Kendall/Hunt Publishing Co., Dubuque, Iowa.
Oswood, M., T. Simpson, L. Saperstein, and S. Nelson. 2001. The freshwater benthos of the
Kanuti National Wildlife Refuge. Kanuti National Wildlife Refuge Final Report FY0101.
Arctic Network
November, 2007
Streams and Lake Monitoring Protocol,
SOP 11 – MacroInvertebrate Field Sampling, v. 1.00
Arctic Network
November, 2007