Abiotic Water Quality Monitoring
Why collect data?
Abiotic water quality testing is an important part of environmental monitoring. When water quality is poor, it affects not only aquatic life but the surrounding ecosystem as well. Water quality monitoring can help researchers (and students!) predict and learn from natural processes in the environment and determine human impacts on an ecosystem. These measurement efforts can also assist in restoration projects or ensure environmental standards are being met.
COMMUNITY PARTNER CONNECTION: How can you contribute to ongoing research or monitoring? What kinds of data do local organizations collect? Is there historical data you can use to make a hypothesis about what you will find in your watershed?
What to test, how to test it, and why is it important?
Dissolved Oxygen | pH | Conductivity | Turbidity | Nitrate | Phosphorus
Dissolved Oxygen
WHAT is dissolved oxygen?
Dissolved oxygen (DO) refers to the level of free, non-compound oxygen (not bonded to any other element) present in water or other liquids. It is an important parameter in assessing water quality because of its influence on the organisms living within a body of water. In limnology (the study of lakes), dissolved oxygen is an essential factor second only to water itself . A dissolved oxygen level that is too high or too low can harm aquatic life and affect water quality.
WHY is dissolved oxygen important?
Dissolved oxygen is necessary to many forms of life including fish, invertebrates, bacteria and plants. These organisms use oxygen in respiration, similar to organisms on land. Fish and crustaceans obtain oxygen for respiration through their gills, while plant life and phytoplankton require dissolved oxygen for respiration when there is no light for photosynthesis. See Oxygen Requirements figure.
Microbes such as bacteria and fungi also require dissolved oxygen. These organisms use DO to decompose organic material at the bottom of a body of water. Microbial decomposition is an important contributor to nutrient recycling. However, if there is an excess of decaying organic material (from dying algae and other organisms), in a body of water with infrequent or no turnover (also known as stratification), the oxygen at lower water levels will get used up quicker.
Dissolved oxygen levels often stratify in the winter and summer, turning over in the spring and fall as lake temperatures align.
Minimum dissolved oxygen requirements of freshwater fish
How dissolved oxygen enters the water
DO levels increase with sunlight as aquatic plants photosynthesize during the day.
WHERE does dissolved oxygen come from?
Dissolved oxygen enters water through the air or as a plant byproduct. From the air, oxygen can slowly diffuse across the water’s surface from the surrounding atmosphere, or be mixed in quickly through aeration, whether natural or man-made. The aeration of water can be caused by wind (creating waves), rapids, waterfalls, ground water discharge or other forms of running water. Man-made causes of aeration vary from an aquarium air pump to a hand-turned waterwheel to a large dam.
Dissolved oxygen is also produced as a waste product of photosynthesis from phytoplankton, algae, seaweed and other aquatic plants.
HOW do we measure dissolved oxygen?
Dissolved oxygen is usually reported in milligrams per liter (mg/L) or as a percent of air saturation. 1 mg/L is equal to 1 ppm. It can be measured using a titration method from the H2OQ water quality testing kit or a color indicating test from the LaMotte Water Testing kit.
RESOURCE: Learn more about dissolved oxygen in freshwater on the Fondriest Environmental Learning Center pages.
pH
WHAT is pH?
pH stands for the “power of hydrogen” . The numerical value of pH is determined by the molar concentration of hydrogen ions (H+) .
WHY is pH important?
If the pH of water is too high or too low, the aquatic organisms living within it will die. pH can also affect the solubility and toxicity of chemicals and heavy metals in the water . The majority of aquatic creatures prefer a pH range of 6.5-9.0, though some can live in water with pH levels outside of this range. If the pH of water is too high or too low, the aquatic organisms living within it will die. pH can also affect the solubility and toxicity of chemicals and heavy metals in the water . The majority of aquatic creatures prefer a pH range of 6.5-9.0, though some can live in water with pH levels outside of this range.
Aquatic pH levels. The optimum pH levels for fish are from 6.5 to 9.0. Outside of optimum ranges, organisms can become stressed or die.
pH levels can fluctuate daily due to photosynthesis and respiration in the water. The degree of change depends on the alkalinity of the water.
WHAT factors influence pH in the water?
There are many factors that can affect pH in water, both natural and man-made. Most natural changes occur due to interactions with surrounding rock (particularly carbonate forms) and other materials. pH can also fluctuate with precipitation (especially acid rain) and wastewater or mining discharges . In addition, CO2 concentrations can influence pH levels. Carbon dioxide is the most common cause of acidity in water. Photosynthesis, respiration and decomposition all contribute to pH fluctuations due to their influences on CO2 levels. The extremity of these changes depends on the alkalinity of the water, but there are often noticeable diurnal (daily) variations . This influence is more measurable in bodies of water with high rates of respiration and decomposition. Carbonate materials and limestone are two elements that can buffer pH changes in water. Calcium carbonate (CaCO3) and other bicarbonates can combine with both hydrogen or hydroxyl ions to neutralize pH.
HOW do we measure pH?
pH is a determined value based on a defined scale, similar to temperature. This means that pH of water is not a physical parameter that can be measured as a concentration or in a quantity. Instead, it is a figure between 0 and 14 defining how acidic or basic a body of water is along a logarithmic scale . The lower the number, the more acidic the water is. The higher the number, the more basic it is. It can be measured using a pH probe from the H2OQ Water Testing Kit or color indicating tablets from the LaMotte Water Testing Kit.
Conductivity
WHAT is Conductivity?
Conductivity is a measure of water’s capability to pass electrical flow. This ability is directly related to the concentration of ions in the water.
WHY is conductivity important?
Conductivity, in particular specific conductance, is one of the most useful and commonly measured water quality parameters. In addition to being the basis of most salinity and total dissolved solids calculations, conductivity is an early indicator of change in a water system. Most bodies of water maintain a fairly constant conductivity that can be used as a baseline of comparison to future measurements. Significant change, whether it is due to natural flooding, evaporation or man-made pollution can be very detrimental to water quality.
RESOURCE: Learn more about conductivity in freshwater ecosystems
Salts dissolve in water to produce an anion and a cation. These ions make up the basis of conductivity in water.
Factors that affect water volume (like heavy rain/evaporation) affect conductivity. Runoff or flooding over soils that are high in salts or minerals can cause a spike in conductivity despite the increase in water flow.
WHAT factors influence conductivity in water?
Conductive ions come from dissolved salts and inorganic materials such as alkalis, chlorides, sulfides and carbonate compounds. Compounds that dissolve into ions are also known as electrolytes. The more ions that are present, the higher the conductivity of water. Likewise, the fewer ions that are in the water, the less conductive it is. Distilled or deionized water can act as an insulator due to its very low (if not negligible) conductivity value. Sea water, on the other hand, has a very high conductivity.
HOW do we measure conductivity?
Conductivity is usually measured in micro- or millisiemens per centimeter (uS/cm or mS/cm). It can be measured using the conductivity probe in the H2OQ Water Kit.
Turbidity
WHAT is turbidity?
Turbidity is an optical determination of water clarity. Turbid water will appear cloudy or murky, affecting the physical look of the water. Suspended solids and dissolved colored material reduce water clarity by creating an opaque, hazy or muddy appearance. Turbidity measurements are often used as an indicator of water quality based on clarity and estimated total suspended solids in water.
Secchi discs are used to measure water clarity. Photo Credit: Minnesota Pollution Control Agency via NASA
Some sediment will settle to the bottom of a body of water, while others remain suspended.
Turbidity can also inhibit photosynthesis by blocking sunlight. Halted or reduced photosynthesis means a decrease in plant survival and decreased dissolved oxygen output
WHY is turbidity important?
Turbidity is the most visible indicator of water quality. Suspended particles can come from soil erosion, runoff, discharges, stirred bottom sediments or algal blooms. While it is possible for some streams to have naturally high levels of suspended solids, clear water is usually considered an indicator of healthy water. A sudden increase in turbidity in a previously clear body of water is a cause for concern. Excessive suspended sediment can impair water quality for aquatic and human life, impede navigation and increase flooding risks.
WHAT factors influence turbidity?
Suspended solids can be comprised of organic and inorganic materials such as sediment, algae, and other contaminants. However, there are specific factors that can affect turbidity levels in a body of water. These are water flow, point source pollution, land use and resuspension.
HOW do we measure turbidity?
Turbidity is measured by Secchi depth. This measurement is based on the depth that a black and white Secchi disc can be seen when lowered into a body of water. At the point visibility is lost, the depth of the disc is recorded, and is known as the Secchi depth. High Secchi depths correspond with low turbidity levels, while low Secchi depths are associated with high levels of suspended solids. This method is generally only useful in oceans, lakes and deep, low-flow rivers.
Nitrate
WHAT is Nitrate?
Nitrates are a form of nitrogen, which is found in several different forms in terrestrial and aquatic ecosystems. These forms of nitrogen include ammonia (NH3), nitrates (NO3), and nitrites (NO2).
WHY is Nitrate important?
Nitrates are essential plant nutrients, but in excess amounts they can cause significant water quality problems. Together with phosphorus, nitrates in excess amounts can accelerate eutrophication, causing dramatic increases in aquatic plant growth and changes in the types of plants and animals that live in the stream. This, in turn, affects dissolved oxygen, temperature, and other indicators. Excess nitrates can cause hypoxia (low levels of dissolved oxygen) and can become toxic to warm-blooded animals at higher concentrations (10 mg/L) or higher) under certain conditions.
WHAT factors influence Nitrate?
Sources of nitrates include naturally occurring animal waste, the natural cycle of decaying plants and animal materials, wastewater treatment plants, runoff from fertilized lawns and cropland, failing on-site septic systems, runoff from animal manure storage areas, and industrial discharges that contain corrosion inhibitors. Nitrates from land sources end up in rivers and streams more quickly than other nutrients like phosphorus. This is because they dissolve in water more readily than phosphates, which have an attraction for soil particles. As a result, nitrates serve as a better indicator of the possibility of a source of sewage or manure pollution during dry weather.
HOW do we measure nitrate?
Both the H20Q and LaMotte water testing kits contain nitrate tests that use the cadmium reduction method to measure nitrate in mg/L. This is a colorimetric method that involves contact of the nitrate in the sample with cadmium particles, which cause nitrates to be converted to nitrites. The nitrites then react with another reagent to form a red color whose intensity is proportional to the original amount of nitrate. The red color is then measured by comparison to a color chart.
Phosphate
WHAT is Phosphorus?
Phosphorus, like nitrogen, is a critical nutrient required for all life. The most common form of phosphorus used by biological organisms is phosphate (PO4), which plays major roles in the formation of DNA, cellular energy, and cell membranes (and plant cell walls). Phosphorus is a common ingredient in commercial fertilizers.
WHY is Phosphorus important?
Too much phosphorus can cause increased growth of algae and large aquatic plants, which can result in decreased levels of dissolved oxygen– a process called eutrophication. High levels of phosphorus can also lead to algae blooms that produce algal toxins which can be harmful to human and animal health.
RESOURCE: USGS: Learn about the relationship between Phosphorus and Freshwater
Toxic Algal Bloom, Lake Erie, 2011 (Credit: NASA)
WHAT factors influence Phosphorus?
There are many sources of phosphorus, both natural and human. These include soil and rocks, wastewater treatment plants, runoff from fertilized lawns and cropland, failing septic systems, runoff from animal manure storage areas, disturbed land areas, drained wetlands, water treatment, and commercial cleaning preparations. High concentrations of phosphorus may result from poor agricultural practices, runoff from urban areas and lawns, leaking septic systems or discharges from sewage treatment plants.
HOW do we measure Phosphorus?
Monitoring phosphorus is challenging because it involves measuring very low concentrations down to 0.01 milligram per liter (mg/L) or even lower. Even such very low concentrations of phosphorus can have a dramatic impact on streams. Both the H20Q and LaMotte water testing kits use tests that measure phosphate in mg/L or ppm.
RESOURCE: Elementary Educators: these Pond Tour Resources may be helpful in simplifying the DO, pH and Nitrate concepts discussed above.
RESOURCE: NGSS aligned lessons from the H2OQ Program for all six of these parameters.
Field-based tools
H2OQ Water Testing Instruments
Tests for:
Dissolved Oxygen
pH
Turbidity
Nitrate
Phosphate
Temperature
Conductivity
safety booklet 2021.pdfLaMotte Water Testing Kit
Tests for:
Dissolved Oxygen
pH
Turbidity
Nitrate
Phosphate
Temperature
Coliform
Classroom-based tools & resources
Analyzing your data
Questions to investigate:
How does our data compare to historical data?
Are there any red flags? Is all data within normal water quality criteria?
How does this data compare to our biotic data?
EPA develops criteria for determining when water has become unsafe for people and wildlife using the latest scientific knowledge. This includes aquatic life, human health, biological, and microbial/recreation criteria. This is a good resource for developing acceptable levels of each parameter.
Submitting/sharing your data
Students and teachers all over Michigan are community scientists contributing their abiotic water quality data using this quick ArcGIS Survey123 form. Zoom into your location, enter your data and use data from other watersheds for comparison (see below).
Sharing back with community partners
Student collected water quality measurements can play a critical role in monitoring water health. It is important to share this data back with community organizations that can help students take action. Community partners can also use their expertise to help analyze the data that was collected.
Comparing your data
Students can design their own Google sheets for compiling data. Exploring Google formulas can be a fun way to connect with Math standards.
US Geological Survey
Real-time and historic water quality data is available for several watersheds in Michigan on USGS's National Water Information System.
Place Based Stewardship Education
Copy of AuGres_FS.pdfNEMIGLSI Case Study: Investigating Local Rivers and Connecting to our Great Lakes
<<Au Gres Elementary students have been monitoring the abiotic water quality of the Au Gres River for nearly a decade!
Community Partner Connections
Who are some of the partners that focus on abiotic water quality in the Great Lakes basin and Michigan?
American Chemical Society -Midland Section
Call a chemist to help with data interpretation, make career connections and more!
Tribal Natural Resource Departments. Here are some examples of tribal Natural Resource/Environmental Department:
Little Traverse Bay Bands of Odawa Indians (Tip of the Mitt), Saginaw Chippewa Indian Tribe (Mount Pleasant area), and Grand Traverse Band of Ottawa and Chippewa (Traverse City area)These are only 3 out of 12 in Michigan!