Tools For Measuring Abiotic Ecological Factors

Abiotic factors are the non-living factors in an environment that affect organisms. They may include air, water, temperature, soil composition, altitude, topography, sunlight availability, latitude and elevation. Ecologists must determine how organisms are affected by these abiotic factors in order to gauge their survival, growth and environmental stressors. Several special tools aid ecologists to determine the characteristics of these abiotic factors.

The temperature of air, water and soil affects the survival of organisms, whether plant or animal. An organism's metabolism relies on certain temperature parameters. Animal species that are poikilothermic, meaning they use behavior to regulate body temperature, prove to be especially susceptible to temperature conditions. Temperature of water affects photosynthesis rates in plants, and lower water temperatures indicate typically higher dissolved oxygen. Temperature ranges over time offer useful information as well. To measure temperature, ecologists use either traditional glass or less breakable digital thermometers. Remote probes called thermistors may be used to measure water temperature.

Light meters are used to measure light intensity. A range of light conditions may exist in different areas, vegetation density and in varying weather, affecting plant growth and photosynthesis.

Ecologists need to measure the pH of soil or water in an environment to see what level the organisms there can tolerate. In water, pH varies depending on the type of environment, whether river, lake or pond; its mineral substrate; and what kinds of plants live in or around it. Industrial pollution runoff leads to lower pH and therefore greater acidity, which affects organisms' survival. Chemical pH tests can be conducted in the field if necessary; however, in the laboratory, digital pH meters prove invaluable.

The slope of an area affects organisms that live in it by creating microclimates. Ecologists use clinometers in slope profiling to measure the slope angle and distance.

Ecologists use anemometers to measure wind speed. Wind speed provides another variable for weather conditions.

Altitude influences where an organism lives, and it affects temperature. Ecologists use handheld altimeters to measure the elevation of environments of interest.

Ecologists use planimeters to measure polar planimetry, which in turn determines the surface area of a site.

Ecologists use Global Positioning System or GPS units to determine coordinates for sites of interest. Some GPS units offer elevation and surface area measurements.

Scientists determine the turbidity, or cloudiness, of water to see how much light can pass through it. Numerous substances affect turbidity, including mud, sand, erosion, runoff and other precipitates. Cloudy water reduces the amount of light that can reach organisms living in water, slows photosynthesis and lowers available oxygen for animals. Turbidity also leads to bacterial growth and can be a factor in potability. Ecologists can use Jackson Candle Turbidimeters, Secchi disks or turbidity tubes to measure turbidity. Turbidity tubes connect visibility and turbidity, are portable and are inexpensive to make.

To record depths along transects of lakes, ecologists use handheld sonar devices. These devices also work well for measuring bathymetry and maximum depth in shallower bodies of water.

A water-level logger is a battery-powered tool that offers continuous measurement of water level. It combines a pressure transducer and data logger.

Ecologists determine water content of soil by measuring fresh soil samples and then drying them in an oven. Finding the difference between the weights of fresh vs. dried soil yields the soil moisture content. High-heat furnaces or Bunsen burners prove useful for burning off humus content in soil samples.

Microscopes enable ecologists to study soil samples. Microscopes can reveal soil texture (such as silt, sand or clay), color and how many rocks a sample contains.

To measure dissolved oxygen in water, ecologists use digital probes. These help determine water quality and oxygen availability for organisms living in water. Higher dissolved oxygen results in better water quality.

Data loggers provide ecologists with a broad capability to combine tools for measuring abiotic factors. Data loggers can be left in the field over long periods, in the site of organisms of interest, recording data. While many commercial data loggers can be expensive and conspicuous, small data loggers can use custom circuit boards and memory cards. These can be programmed for many different functions and environmental parameters.