Introduction to Lake Surveys Basic Water Quality Assessment Unit 3 Module 8 Part C Lake Sampling
Objectives Students will be able to: · explain methods used for collecting water, sediment and aquatic organisms. · identify reasons for collecting water and sediment samples. · compare and contrast the characteristics and use of discrete water samplers, integrated water samplers, grab samples and pumps. · explain methods used for collecting contaminants and microbes. · utilize guidelines to determine the size of the water sample needed to conduct specific analyses. · demonstrate specified labeling techniques. · describe the different methods of sediment sampling. · categorize aquatic organisms by size. · describe procedures used in sampling phytoplankton/algae, periphyton, zooplankton, and benthic invertebrates. · compare and contrast direct and indirect quantitative analysis with qualitative analysis used to study phytoplankton. · classify periphyton by the substrates they grow on. · compare and contrast quantitative and qualitative analysis used to study periphyton, zooplankton, and benthic invertebrates. · describe procedures used in sampling aquatic vegetation. · explain the importance of diatoms in determining water quality. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 2
Basic water quality assessment These slides focus on learning basic field techniques used by limnologists: · Morphometry - estimating critical lake basin measurements · Field Profiles - physical and chemical parameters measured from top to bottom of the water column · Sampling – collecting water, sediments, and aquatic organisms Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 3
Lake sampling · This module contains information about the basic techniques needed to perform a baseline characterization of a lake. · Learn how to collect water, sediment and aquatic organisms from different habitats. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 4
Lake sampling Water samples collected for: · · · · major ions nutrients chlorophyll-a, phytoplankton total suspended solids, turbidity color, organic carbon, biochemical oxygen demand Iron (Fe) and other metals (special case mercury-Hg) organic contaminants (PCBs, PAHs, pesticides, hydrocarbons) · bacteria (fecal coliforms, E. coli and other pathogens) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 5
Lake sampling Sediment samples collected for: · bulk properties · nutrients · contaminants (heavy metals, organics) · organisms · paleolimnological studies of lake history (fossil algae, zooplankton, insects, pollen) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 6
Lake sampling Aquatic Organisms: · Phytoplankton · Zooplankton · Benthos and sediment · Aquatic vegetation · Fish and fish habitat assessment Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 7
Water sampling · Conventional · Automated water sampling · Contaminants · Microbes · How much to collect ? · Sample preservation and storage · Where to sample ? Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 8
Water sampling – conventional Conventional: · Discrete water samplers · Van Dorn, Kemmerer, Go-flow, Niskin and other closing bottles that collect water samples at discrete depths · Integrated water samplers · Tubes that composite water from the surface to a set depth · Grab samples · Dipping a bottle at the water surface · Pumps · Can provide discrete or integrated samples Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 9
Water sampling – discrete samplers · Uses bottles that have external trip mechanisms that close the bottle at depth. · Requires a carefully metered or measured, nonstretching rope or cable · nylon is notorious for stretching over 10% · tightly braided cotton or synthetic “non-stretch” sail rigging lines (<5% stretch) work well · research vessels with winches use steel cable Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 10
Water sampling – devices · Which one to use? CTD with Rosette Van Dorn Niskin Kemmerer Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 11
Water sampling - conventional · The closing mechanism on the sampler is triggered by dropping a weight called a messenger down the line · Make sure the line is vertical; attach appropriate weights if it is angled due to currents or boat drift www. wildco. com Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 12
Water sampling – integrated samplers · Integrated water samplers: · Used to collect water representing an entire column of depths (e. g. , 0 to 2 m) and mix it into one composite sample. · Simple to use and inexpensive to make · Can be made with rigid PVC or flexible tubing · Many state long-term monitoring programs use a 2 meter sampler since this stratum is where most of the algal activity is during the stratified period. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 13
Water sampling – integrated samplers · Method · Tube is lowered to desired depth · Surface end is capped to allow air pressure to hold the water in the tube · Bottom end of tube is raised, cap removed and sample is allowed to flow out into a bottle or carboy Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 14
Water sampling – grab samples · Sometimes it is OK just to dip a bottle into the water to sample. · Usually, this is the method of choice for collecting contaminants and bacteria (while wearing clean and sterile gloves). · This is a good method to use to sample a surface algal scum. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 15
Water sampling – pumps Pump types · Peristaltic pumps · Bilge pumps and submersible pumps are also sometimes used http: //www. forestry-suppliers. com Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 16
Water sampling – pumps Advantages · Greater volumes at discrete depths · Shallow lake sampling without disturbing sediments · Samples from depth can be collected with little or no exposure to the atmosphere (i. e. , anoxic sample) · Good for trace elements and organics because sample only comes in contact with the tubing (silicone or teflon) Disadvantages · Requires power · Head pressure – pump must be able to overcome hydraulic head to pull up water from depth over the side of the boat. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 17
Water sampling – automatic samplers · Primarily for stream, estuary and storm water collection · Usually triggered remotely: · Phone call via modem · Precipitation or high flow · Water quality parameter measured with an automated sensor exceeds a preset level Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 18
Water sampling – contaminants - metals Mercury (Hg) in water · Equipment cannot have metal or rubber components · Containers require special preparation to ensure no Hg contamination · Clean hands/dirty hands technique · Usually, but not always, tissue and sediment sampling do not require “ultra-clean” techniques Other priority pollutant metals · Usually, but not always, less stringent protocols than for Hg because problem levels only occur when concentrations in water are much higher than for Hg (see notes) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 19
Water sampling – contaminants - organic Organic contaminants · PCB’s, PAH’s, pesticides, etc. · Containers specially cleaned with solvents (hexane, acetone, methanol…) · Glass or teflon bottles in most cases · Aluminum foil, solvent cleaned, for fish tissue · Sediments stored in glass jars using plastic or teflon utensils · Sometimes bake (> 550 o. C) glassware to vaporize trace organic chemicals Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 20
Water sampling - contaminants · Clean hands/dirty hands (CH/DH) method should be used for collecting and processing samples vulnerable to trace contamination by metals or trace organic compounds. · CH/DH are required when collecting samples to be analyzed for metals (e. g. , Hg) and other trace organic contaminants and inorganic elements. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 21
Water sampling - microbes · Sterile technique: · Containers must be sterilized by autoclaving or with gas used to kill microbes · Take care not to contaminate the container · Water samplers should be swabbed with 70 % alcohol Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 22
Water sampling – microbes · Grab samples taken with sterile containers Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 23
Sampling – how much water do you need? · Depends on the parameters to · · be analyzed Chlorophyll and TSS often require the greatest volume (> 1 L) Better to be safe and have too much water rather than too little Often depends on how productive the system is Also depends on how practical it is to carry out large volumes of water Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 24
Suggested sample volumes Analyte/ volume table chlorophyll Volume needed >500 m. Ls TSS Often > 1 L total phosphorus total nitrogen anions 200 to 500 m. Ls Dissolved nutrients Total and dissolved carbon ~ 100 m. Ls ~60 m. Ls Metals ~60 m. Ls color, DOC ~60 m. Ls Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 25
Lake sampling – filling the bottles · Rinse containers with a small amount of sample, discard, then fill with fresh sample · Fill bottles completely to eliminate head space (unless the bottles are going to be frozen immediately) · If using cubitainers put the cap on loosely, squeeze out all of the air, then tighten the cap · Leave space in bottles that are to be frozen Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 26
Lake sampling – sample bottles · Cubitainers work well for bulk samples that are to be split and processed later in the laboratory. · High density polyethylene wide mouth bottles (60 to 1 L volume) work well for most analytes. They freeze well, don’t crack and the wide mouth is easy to fill. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 27
Lake sampling – sample labeling · An unlabeled sample may as well just be dumped down the drain. Developed by: E. Ruzycki and R. Axler · Use good labels not masking tape, etc. Poor labels often fall off when frozen samples are thawed. · Use permanent markers NOT ball point pens, pencils in a pinch Updated: 12 -14 -03 U 3 -m 8 c-s 28
Lake sampling – sample labeling · A simple sample label with the minimum amount of information needed… project WOW Shagawa Lake 7/26/02 1 m Site, date, depth RAW, frozen Sample processing and preservation info Often, much more information may be needed by the laboratory performing your analyses. You will also need to supply a chain of custody form. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 29
Sediment sampling http: //www. fdlrez. org/nr/environmental/water. htm Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 30
Sediment sampling · Dredges · Commonly used to grab a bottom sediment sample in lakes, estuaries and slower moving rivers · Collect soft sediments (mud and muck) for sieving out benthic organisms and also obtaining bulk sediment characteristics · Common types · · · Ekman Peterson Ponar Quantitative corers Box corers Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 31
Sediment sampling – Ekman dredge Photos of sediment samplers www. wildco. com Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 32
Sediment sampling – Ekman dredge · small, light, easy to trigger by messenger (usually) · stainless steel – usually OK for contaminants · best for muck, soft mud and silt where a relatively undisturbed sample down to 15 cm or more may be collected · most common size = 6 inch cube (15 cm) · not as good for sand; if sediment is compacted, or if much gravel, rocks, or large debris is present, the heavier Peterson or Ponar dredge is preferred Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 33
Sediment sampling – Ekman dredge · This animation of the Ekman dredge, illustrates the chain of events during use. http: //www. cee. vt. edu/program_areas/environmental/teach/smpr imer/dredges. html Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 34
Sediment sampling – Ekman dredge Sample collection photos Extruding (sub-coring) Into the baggie… Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 35
Sediment sampling – Ekman safety The jaws humor photo are strong …. be careful Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 36
Sediment sampling – Peterson and Ponar · usually require winches · can sample coarser photos material than the Ekman (small woody debris and gravel) Peterson Ponar www. wildco. com Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 37
Sediment – “quantitative” corer · variety of devices to collect undisturbed cores www. wildco. com Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 38
Sediment sampling – box corers · Used for large lake and oceanographic research Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 39
Sampling aquatic organisms · Learn how to collect water, sediment and aquatic organisms from different habitats. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 40
Sampling aquatic organisms – algae · Phytoplankton (float freely in the water) · Periphyton (attached to aquatic vegetation, rocks, wood and other substrates) · Benthic algae (grow on the lake bottom/sediments); also sometimes called periphyton www. duluthstreams. org/understanding/algae. html Developed by: E. Ruzycki and R. Axler www. cawthron. org. nz/periphyton_image. htm Updated: 12 -14 -03 U 3 -m 8 c-s 41
Sampling aquatic organisms – zooplankton · Zooplankton: · Crustaceans (Cladocerans, copepods) · Rotifers · Protozoans, ciliates · Aquatic insects (e. g. , Chaoborus) www. aims. gov. au/pages/research /hatchery-feeds/hfa-01. html http: //cgee. hamline. edu/see/questions/dp_biosph ere/bios_place/dp_bios_place_ocean. htm Developed by: E. Ruzycki and R. Axler http: //lsda. jsc. nasa. gov/scripts/cf/res ult 2. cfm? mis_index=110 photo source: North American Benthological Society Updated: 12 -14 -03 U 3 -m 8 c-s 42
Sampling aquatic organisms - benthos · Benthic macroinvertebrates · Aquatic insects (adults and larvae) · Leeches · Crayfish · Mussels, snails http: //www. usask. ca/biology/skabugs/ Developed by: E. Ruzycki and R. Axler http: //www. usask. ca/biology/skabugs/ Updated: 12 -14 -03 U 3 -m 8 c-s 43
Sampling aquatic organisms · Aquatic macrophytes · Submergent · Emergent · Floating · Bacterioplankton · Fish · Paleolimnology- reconstructing historical biological communities · Algae (usually diatoms) · Zooplankton · Benthic invertebrates Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 44
Sampling aquatic organisms · An alternate way of grouping aquatic organisms: · Plankton (open water communities) = phytoplankton and zooplankton · Benthos (bottom communities) = periphyton, benthic macroinvertebrates, aquatic macrophytes · Fish (organisms that go where they choose) · Dead stuff = detritus Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 45
Sampling aquatic organisms – by size · Most plankton sampling techniques are size selective (based on mesh size). · Phytoplankton range in size from 0. 2 um to > 200 um (from bacteria sized to colonies and filaments easily seen by the human eye). · Zooplankton range from single-celled protozoans, < 80 um rotifers, to crustaceans and insects (up to millimeters in length). www. aims. gov. au/pages/re search/hatchery-feeds/hfa 01. html Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 46
Sampling aquatic organisms – by size · Terminology is often confusing · Nannoplankton: < 60 m · Net plankton: > 80 m · From Wetzel 2001: · picoplankton: 0. 2 to 2. 0 m · ultraplankton : 2 to 20 m · microplankton: 20 to 200 m; usually refers to phytoplankton · Macroplankton: > 2 mm (2000 um) and up to cm in length · Densities are expressed as: · individuals per unit volume (#/L) · biomass or weight (mg/L) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 47
Sampling aquatic organisms – by size Sizes Freshwater Plankton Classifications with Suggested Mesh Micron Size Plankton Classification Reference table of sizes ranges 1000 Largest zooplankton and icthyoplankton (larval fish) 750 Larger zooplankton and icthyoplankton 600 Large zooplankton and icthyoplankton 500 Small zooplankton and icthyoplankton 363 Large microcrustacea 243 Microcrustacea 153 Microcrustacea and most rotifers 118 Small rotifers 80 Net phytoplankton and net zooplankton 63 Large nannoplankton and large diatoms 10 Small nannoplankton Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 48
Sampling - algae/phytoplankton · Phytoplankton (float freely in the water) · Periphyton (attached to aquatic vegetation, rocks, wood and other substrates) · Benthic algae (grow on the lake bottom/sediments); also sometimes called periphyton Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 49
Sampling - algae/phytoplankton I. Goals of analysis 1. Quantitative, direct; biomass, cell density 2. Quantitative, but indirect; measuring chlorophyll concentration 3. Qualitative; presence/absence, dominance II. Sampling 1. Methods 2. Frequency Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 50
Sampling - algae/phytoplankton III. Ancillary information IV. Preservation methods: IV. Counting methods: · · taxonomic guides counting chambers, slides microscopes Archiving V. Monitoring for toxic algae Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 51
Phytoplankton – I. Goals of analysis 1. Quantitative analysis (direct): · For monitoring and research purposes · Requires a high level of expertise · The cost (~$250/sample) and time involved are usually too high for a typical water quality assessment · Typically surface water (0 m) or a 0 -2 m composite is collected for long-term monitoring (because noxious scums of blue-greens collect in surface water; site of water contact recreation) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 52
Phytoplankton – I. Goals of analysis 2. Quantitative analysis (indirect): · such as chlorophyll concentration, provide an excellent index of the total amount of phytoplankton, but not what species are actually present. · A cost-effective strategy for many long-term monitoring efforts is to combine chlorophyll data with periodic qualitative community structure estimates. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 53
Phytoplankton – I. Goals of analysis 3. Qualitative analysis · Yields presence/absence information · Costs less to analyze · Still requires taxonomic expertise but goals of analysis are often different than quantitative (i. e. , ID to genus level is often enough) or even to Class (blue-greens, diatoms, greens etc. ) · Collected as a whole water sample or by plankton net Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 54
Phytoplankton – II. Sampling 1. Methods · Whole water; integrated or grab sample · Nets: mesh size appropriate to analysis goals · 10 um mesh will capture most phytoplankton; clogs easily however · Blue-green algal scum can often be sampled by dipping a sample bottle – but is effected by: · · time of day wind conditions Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 55
Phytoplankton – II. Sampling Images of phytoplankton samplers Integrated (whole water) sampler www. wildco. com http: //www. fdlrez. org/nr/environmental/water. htm Van Dorn (whole water) sampler Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 Plankton net U 3 -m 8 c-s 56
Phytoplankton – II. Sampling 2. Frequency · Weekly to bi-weekly sampling is necessary to capture the seasonal dynamics of phytoplankton and to quantify abundance and biomass. · Monthly may be adequate to provide an overall picture of the changes occurring in the ice-free growing season when water quality criteria are usually most critical. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 57
Phytoplankton – III. Ancillary information · Chlorophyll · The most common estimator of algal biomass · Ideally best to have both chlorophyll and algal community identification · More sophisticated techniques are becoming more available for major algal groups via detailed pigment analysis · Other important data · Note any unusual odors when sampling · Secchi depth and nutrients, silica · Temperature, DO, and light profiles Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 58
Phytoplankton – IV. Sample preservation · Lugol’s Iodine · Store in airtight glass container · Store in darkness (light sensitive) · Stains starch a dark color which is useful for identifying green alga · Add enough to make 1% solution (~ 0. 5 m. L to 50 m. L sample yields the color of a fine brandy) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 59
Phytoplankton – IV. Sample preservation · Other preservatives: · acid formalin solution (FAA) · Gluteraldehyde · These are known or suspected carcinogens and OSHA and state regulations for the workplace should be checked before use · Long-term archiving may prove useful to identify trends in species composition or even changes in morphology Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 60
Sampling - periphyton · Periphyton (attached to aquatic vegetation, rocks, wood and other substrates) · Benthic algae (grow on the lake bottom/sediments); also sometimes called periphyton Developed by: E. Ruzycki and R. Axler Photo source: Tahoe Research Group, U California-Davis Updated: 12 -14 -03 U 3 -m 8 c-s 61
Sampling - periphyton · Periphyton are algae attached to solid substrates; bottom sediment, rocks, twigs, beer cans, VW Beetles · These benthic algae are classified by the substrates that they grow on: · · · Epilithic- on rock or other non-living substrate Epiphytic- on plants Epizoic- on the surface of an animal Epipelic- on soft organic or silty sediments Episammonic- on sand Epirefusic- on garbage in the lake Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 62
Periphyton - sampling I. Goals of analysis 1. Quantitative: · biomass, chlorophyll (standing crop) per unit area, species ID, AFDW, organic matter 2. Qualitative · presence/absence, relative abundance, dominance II. Sampling methods III. Preservation Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 63
Periphyton – I. Goals of analysis Do you want to estimate the actual in situ (i. e. , in place) amount of periphyton or do you want a index of how well periphyton might grow at one site relative to another? · In-situ sampling: · remove all the material in a prescribed area · Artificial substrates: · provides easily calculated areal estimates, are cheap, and easy to deploy / retrieve Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 64
Periphyton – II. Sampling methods · Artificial substrates (these are slide holders) Before… …. . and after Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 65
Periphyton – II. Sampling methods · One way to scrape a known area is to lay a plastic 35 mm slide (film removed) over the rock and scrape off the material within the slide area Developed by: E. Ruzycki and R. Axler scrub area = 2. 3 cm. X 3. 5 cm=8 cm 2 Updated: 12 -14 -03 U 3 -m 8 c-s 66
Periphyton – II. Sampling methods Visual of matter taken from a rock Rocks don’t always look like they have much on them Nearly all the stuff scrubbed off this rock was organic matter –most of it living algae S. Loeb and J. Reuter images Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 67
Periphyton – II. Sampling methods · Resulting material from a rock scrub (to the right) containing: · Macroinvertebrates · Detritus · Fungi · Bacteria · as well as algae Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 68
Periphyton – II. Sampling methods Photos of sampling methods http: //www. nmu. edu/wwwedgar/biology/web/Strand/wave%20 zone. htm Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 69
Periphyton – III. Preservation methods · Lugols’s iodine can be used if the algae of interest are soft bodied forms (i. e. , blue-greens and green algae). · If interested only in diatoms, it may be best to preserve in 70% ethanol. · Freeze sediment samples if they are to be analyzed for surficial chlorophyll. www. urbanrivers. org/web_images/diatoms. gif Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 70
Zooplankton - sampling methods Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 71
Zooplankton I. Goals of analysis 1. Quantitative: · biomass, absolute abundance 2. Qualitative · presence/absence, relative abundance, dominance II. Sampling 1. Methods 2. Frequency iii. Ancillary information IV. Preservation methods Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 72
Zooplankton – I. Goals of analysis · Biodiversity · Abundance · Biomass · Community/ecosystem interactions (food webs) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 73
Zooplankton – I. Goals of analysis, cont. 1. Qualitative-presence/absence of different species · Relatively simple qualitative techniques; less expensive 2. Quantitative · Determining absolute and relative abundance of different species; more expensive and time intensive · Again, as for the algal community, you must assess whether increased effort to obtain more detailed information is worth the time and expense Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 74
Zooplankton – II. sampling methods · Plankton bottles, traps, tubes, pumps and nets · Mesh size: balance between catching smaller organisms such as rotifers without reducing net efficiency too much due to algal clogging because of small mesh size · Vertical net tows are the simplest approach · Collect vertically-integrated samples from the entire water column or use a closing net that can sample a discrete depth stratum (e. g. , 5 to 10 m) · Discrete depth samplers (e. g. 10 m) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 75
Zooplankton – II. sampling methods, cont. · Zooplankton distribution varies seasonally, temporally, and spatially in a lake · Widely variable across the lake, inshore vs. offshore and from day to night (diel “dye-eel” variations) · Zooplankton can sometimes avoid nets and traps · Sampling effectiveness may vary for Crustacea, macrozooplankton, and Rotifera Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 76
Zooplankton – sampling methods Birge closing net and Wisconsin Net Simple zoop nets Zooplankton samplers wildco. com Schindler traps for sampling discrete depths Aquatic Research Instruments Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 77
Zooplankton – using a net · Nets should be hauled from just above the lake bottom to the lake surface at a constant speed (about 1 sec per meter or as a rule of thumb, count 1000, 2000 etc. , as you pull the net in hand-over-hand). · Information required for quantitative analysis includes: · depth of tow, · mesh size, · diameter of net opening Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 78
Zooplankton – using a net · Wash plankton concentrate into a jar/bottle with filtered lake water · Rinse net at least with filtered lake water or by raising and lowering the net (without introducing new lake water through the mouth) Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 79
Zooplankton – using a net · Nets can sample a large volume of water Example Using a Wisconsin net with a small, 13 cm diameter opening for a 0 to 5 m vertical tow: Where d = 0. 13 m and z = 5. 0 m = 0. 66 m 3 = 66 liters Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 80
Zooplankton – III. Sample preservation 1. Zooplankton samples can be preserved in 95% ethanol or 5% formaldehyde (formalin). 2. Animals preserved in formalin sometimes become distorted, which complicates size measurements. One solution involves the addition of 40 g/L sucrose to the 5% formaldehyde. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 81
Benthic invertebrates New Section Photo Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 82
Benthic invertebrates I. Goals of analysis 1. Qualitative: presence/absence, relative abundance, dominance, biodiversity 2. Quantitative: biomass, absolute abundance, biodiversity II. Sampling 1. Methods 2. Frequency III. Preservation IV. Equipment Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 83
Benthic invertebrates – Qualitative · Simple, cost-effective · Easily standardized and repeatable · Number of sampling sites should reflect the habitat diversity: · Substrates; bedrock, cobbles, sand, mud, organic debris, rooted macrophytes · Groundwater upwellings, lake inflows and outflows · Different wave exposures · Different types of shoreline vegetation Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 84
Benthic invertebrates – Qualitative · Near shore sampling · Rock pick · Kick and sweep · Activity trap · Off shore sampling · Grab (Ekman sampler) · Nighttime vertical net tow St Louis Riverwatch http: //lakes. chebucto. org/contract. html Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 85
Benthic invertebrates - Quantitative · Quantitative sampling · Density expressed as individuals per unit area; biomass per unit area · Sampling methods dependent upon substrate and habitat type · Use cores of known cross-sectional area (usually 5 to 10 cm diameter) for soft sediments · Emergence traps Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 86
Benthic invertebrates – II. Sampling Photos of various traps / nets sediment cores activity traps dip nets sediment dredges Wildco. com Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 87
Benthic invertebrates – Sampling · Adult emergence traps · http: //www. usask. ca/biology/skabugs/Candle. L. html Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 88
Benthic invertebrates – III. Preservation · 10 % formalin · Good for general use but remember that formalin is a carcinogen · Fixes (preserves tissues well) · 70 % ethanol · Good preservative but does not fix tissue · Low toxicity to humans · Major disadvantage is that large volumes are required, which can be difficult to carry in the field. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 89
Aquatic vegetation Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 90
Aquatic vegetation · Visual assessment · Grabs · Census transects (point and quadrant) · Aerial surveys AW Research Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 91
Aquatic vegetation · Aquatic plant survey methods vary, depending on the objectives of the study. Including: · Surveying for a particular species (e. g. , an exotic species) · Creating a plant community map · Conducted as part of a general fish and wildlife habitat survey Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 92
Aquatic vegetation · Survey techniques must account for the three growth types: · Emergent · Submergent · Floating Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 93
Aquatic vegetation · Plant survey: · Surface survey – uses a boat and trained observer to survey the littoral zone · Divers can produce similar but more thorough results · Aerial survey – works well for looking for wetland species like purple loosestrife or floating species but doesn’t work well for submerged species. · Satellite imagery is potentially well-suited for aquatic plant surveys in lakes and wetlands and current research shows promise Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 94
Aquatic vegetation · Satellite image of Swan Lake, MN · UM researchers are determining the effectiveness of this technique Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 95
Aquatic vegetation Developing a map of the aquatic plant community · Surface survey · Quick but not very accurate if the water is turbid · Sample regularly at different depths · A weighted plant rake (rake on a rope) can used as a sampling tool · Plants are marked on a map as they are identified http: //www. state. ma. us/dem/programs/lakepond/ Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 96
Aquatic vegetation · Here is a graph showing the % cover of several aquatic plant species in Lake Independence (MN). Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 97
Aquatic vegetation · Here is a presence/ absence map from Lake Okeechobee. · This type of map is useful in tracking the spread of exotic species from year to year. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 98
Aquatic vegetation · Quantifying aquatic plants Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 99
Fish New section - fish image Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 100
Fish Image of large fyke net Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 101
Fish Netting fish - photo Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 102
Fish Lab investigation photo Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 103
Paleolimnology Photos of microscopic images Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 104
Paleolimnology · Paleolimnology is the study of past freshwater, saline, and brackish environments · In some cases, the history of the water body itself is important, but typically information is used in a wider geographical and ecological context · These clues can often result in quantitative and qualitative reconstructions of important lake chemistry and biology Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 105
Paleolimnology – diatoms · Diatoms are powerful indicators of water quality · There are hundreds of species in all aquatic habitats · They respond quickly and integratively to environmental gradients · Diatoms are the most used group of algae used in bioassessment Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 106
Paleolimnology – diatoms · A sediment core is collected · The fossils, geological, and chemical signals that are preserved in the core are the clues to revealing the ecological history of the lake and the surrounding landscape. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 107
Paleolimnology – diatoms · The core is essentially sliced into slabs (1 to 4 cm) that represent different historic time periods. · The sub-samples are dated using 210 Pb and other isotope methods to determine the age and sediment accumulation rates over the past hundreds of years. Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 108
Paleolimnology – diatoms Graphical representation Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 109
Profiling techniques New section – image of profiling techniques Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 110
Physical and chemical profiles – Ex. 1 Grindstone Lake · Temp gradient sharpest from 5 -6 m · No really sharp gradients in DO where it drops to critical levels · Conclusion: You might sample every meter to ~ 8 – 10 m to characterize thermocline. Then sample at 2 or even 5 m intervals to save time without losing much information. Developed by: E. Ruzycki and R. Axler DO T Updated: 12 -14 -03 U 3 -m 8 c-s 111
Physical and chemical profiles – Ex. 2 · West Upper Lake Minnetonka · Temp gradient sharpest from * DO is already zero at 13 m and 10 temp is decreasing near linearly -11 m · DO also sharp from 10 11 m, dropping to zero. · Conclusion: sample every meter to ~12 m to characterize thermocline and “oxycline. ” Then sample at 2 m intervals to save time without losing information. Developed by: E. Ruzycki and R. Axler DO T Updated: 12 -14 -03 U 3 -m 8 c-s 112
Physical and chemical profiles – Ex. 3 · Sampling interval decisions become more important when you’re on a deep lake (>50 m) where time at a site is important. · Lake Mead is 150 m deep · Lake Washington is > 65 m Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 113
Physical and chemical profiles – Ex. 3 Profile of lake Washington Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 114
Developed by: E. Ruzycki and R. Axler Updated: 12 -14 -03 U 3 -m 8 c-s 115
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