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For maximum learning, cruise participants should be introduced to the following terms, which are frequently used in this manual and aboard the vessel.

ACID - Any substance that can donate a hydrogen atom or proton (H+) to any other substances. Examples are vinegar and hydrochloro acid.
ACCURACY - The closeness of a measured value to a true value.
AFT DECK - Area in the back (stern) of the vessel as opposed to the area in the front of the vessel (bow).
ALGAE - Simple, photosynthetic aquatic plants that lack true roots, stems or leaves.
ALGAL BLOOMS - Extensive growth of algae in a body of water often due to increased nutrients such as nitrates and phosphates from fertilizers.
ALKALINITY - Alkalinity is a measure of the capacity of water to neutralize acids. This is known as the buffering capacity of water that is the ability of water to resist a change in pH when acid is added. Alkalinity in water is due primarily to the presence of bicarbonate, carbonate, and hydroxide ions.
AMBIENT TEMPERATURE - The current temperature of the surroundings. Ambient water temperatures may differ from the ambient air temperature.
BEAKER - Container with a spout used to transport, pour, and/or mix liquids or solids.
BENTHOS - A term applied to organisms that live on or in the bottom of a body of water and its sediment (benthic zone).
BLOODWORMS - Midge fly larvae found in the bottom of lakes. Their red color is due to a chemical similar to the hemoglobin that is found in human blood.
BUFFER - Standard solutions of a known value, such as pH 7 and pH 10, used to calibrate pH meters. Buffers resist changes in pH.
BUFFERING CAPACITY - The buffering capacity of water refers to the ability of the water to neutralize acids. Limestone (calcium carbonate) is a natural buffer that helps to maintain soil and water pH near neutral.
CALIBRATION - Determination of the correct value of each setting on an instrument by comparison with a standard or known value.
CONDUCTIVITY - The measure of a substance's ability (in our case, water) to carry electricity. Conductivity depends on the concentration of charged particles (ions) and temperature. It is measured in micromhos (mmho/cm).
CONDUCTIVITY METER - An instrument consisting of two electrodes (positive and negative) that measure the flow of electricity between them.
CONSUMERS - Organisms that eat other organisms or plants for nutrition.
CUVETTE - A special container (sample cell) used to hold a small volume of water for certain measuring instruments such as turbidity meter.
DATA - The information (numerical and observational) gained through research.
DEIONIZED WATER - Water that has had all of its charged particles (ions), other than hydrogen and hydroxide ions, removed.
DENSITY - The ratio of the mass of a substance to its volume.
DEPTH SOUNDER - An instrument that sends and receives impulses indicating how deep the water is as well as the bottom contours.
DETRITUS - Dead and decomposing organic matter.
DIATOMS - Single-celled microscopic plants with hard "shells" of silica.
DIGITAL TITRATOR - An instrument used in the dissolved oxygen analysis that delivers a measured amount of chemical solution (titrant) to the water sample.
DISSOLVED OXYGEN - Oxygen gas molecules dissolved in water that are available for living organisms to use. Abbreviated DO. Measured in parts per million (ppm). DO solubility varies with water temperature and pressure.
ECOSYSTEM - A system of interrelated organisms and their physical and chemical environment. It includes both the biotic (living) community and the abiotic (non-living) environment.
ERLENMEYER FLASK - Container having a wide bottom and smaller neck and mouth; used to mix liquids.
EROSION - The wearing away of land surfaces by running waters, glaciers, winds, and waves. Erosion occurs naturally from weather or runoff but can be intensified by land-clearing practices related to farming, residential or industrial development, road building, or timber cutting.
EUTROPHIC LAKE - A lake that has high concentrations of nutrients; often shallow with periods of low oxygen.
EUTROPHICATION - The natural or artificial addition of nutrients to a body of water resulting in increased growth of plants. Acts as an aging process in a body of water and may cause decreases in dissolved oxygen. Accelerated aging of lakes by human activity is called cultural eutrophication.
EXOTIC SPECIES - Species or organisms found beyond their natural range or zone of potential dispersal. They have been intentionally or accidentally introduced outside their natural ranges. Also referred to as non-indigenous species. Examples are the zebra mussel, spiny waterflea, and sea lamprey.
FOOD CHAIN - A series of feeding relationships where organisms at one level serve as food for a higher level of organisms.
FOOD WEB - The many interconnected food chains of a biological community.
FOREL-ULE COLOR SCALE - A uniform way to measure the color of water using glass tubes filled with colored solution. (See water color scale).
GLOBAL POSITIONING SYSTEMS (GPS) - A system of satellites, ground stations, and GPS receivers. Ground stations monitor satellites in "known" positions and triangulation is used to determine such things as latitude and longitude or the location of the vessel or other vehicles.
GRADUATED CYLINDER - A cylindrical-shaped piece of laboratory equipment that is marked in units for measurement of liquids.
HEAD - Restroom and toilet. Unisex. Make sure door is locked when in use.
HERO PLATFORM - A special restricted area extending out from the side of the vessel from which instruments are lowered into the water.
HYPOTHESIS - A tentative statement made to test logical or empirical consequences.
INDICATOR SPECIES - Certain organisms, in part, that help determine water quality (clean versus polluted).
IONS - Electrically charged atoms or groups of atoms that are capable of conducting an electrical current in water. They may be positively or negatively charged. In neutral water, there are equal concentrations of hydrogen (H+) ions and hydroxyl (OH-) ions. Salt water has significant amounts of sodium (Na+) and chloride (Cl-) ions.
LABORATORY - Area inside the vessel where various tests are run and special equipment is maintained and used to collect data.
LATITUDE - A geographical measurement made up of degrees, minutes, and seconds. It is measured north or south with reference to the equator. This measurement is obtained from the GPS.
LIFE VEST - A garment worn to help a person float in case they fall in the water. Also known as a Personal Flotation Device (PFD).
LIMNOLOGY - The science of studying freshwater. Limnologists study freshwater systems and oceanographers study marine (salt-water) systems.
LOGARITHMIC SCALE - A scale in which each unit increment represents a tenfold increase or decrease such as a pH scale.
LONGITUDE - A geographical measurement made up of degrees, minutes, and seconds. It is measured east or west of the Prime Meridian.
MAGNETIC COMPASS - A device for determining directions by means of a magnetic needle swinging on a free pivot and pointing to the magnetic North.
MICROORGANISMS - Organisms too small to be seen with the unaided eye, including bacteria, protozoans, yeasts, viruses, and algae.
MICROSCOPE - An optical device used to magnify very small objects. It may have one eyepiece (monocular) or two eyepieces (binocular or stereoscopic).
MILLIGRAMS PER LITER - A unit (abbreviated as mg/L) used to measure dissolved oxygen and other chemicals. It is a measure of concentration, not absolute amounts. [Note: 1 mg/L = 1 ppm]
NITRATE - A salt of nitric acid (HNO3). Nitrates are often highly soluble and can be reduced to form nitrites and ammonia.
NUTRIENT - Chemical substances such as nitrates, phosphates, or potassium that are necessary for plant growth.
OLIGOTROPHIC LAKE - Deep, clear lake with low nutrient supplies and little organic matter. Characterized by high transparency and high dissolved oxygen levels.
ORGANISM - Any living being such as plants, animals, fungi, bacteria, etc.
PARTS PER MILLION - A unit (abbreviated as ppm) used to measure dissolved oxygen and other chemicals. It is a measure of concentration, not absolute amounts. For example, one inch in sixteen miles is one ppm. [Note: 1 mg/L = 1 ppm]
PELAGIC - Open water zone.
PERCENT OXYGEN SATURATION - Percent of the potential amount of dissolved oxygen that water will hold at a given temperature.
pH - A numeric value that indicates relative acidity and alkalinity on a scale of 1 to 14. A pH value of 7.0 is neutral. Acids have pH values less than 7, bases have pH values greater than 7. Acid rain has a pH of less than 5.6.
PHLEGER CORER - A weighted hollow tube used to sample the bottom sediment layers.
PHOTOSYNTHESIS - Production of food (carbohydrates) and oxygen by plants from carbon dioxide and water in the presence of chlorophyll and sunlight.
PILOT HOUSE - The area or compartment in which the captain operates the ship.
PLANKTON - Plants (phytoplankton), animals (zooplankton), and other organisms that drift in the water column. They are often microscopic but range in size from single-cells to large oceanic jellyfish.
PLANKTON NET - A funnel-shaped device of fine meshed cloth which will permit water to pass through it, but not microscopic organisms.
PLUME LINE - The point of separation between river water and Lake Michigan water due to such factors as temperature, turbidity, or microorganisms.
POLLUTANT - Any substance introduced to the environment that adversely affects the usefulness of a resource.
PONAR GRAB SAMPLER - A weighted, metal, jaw-like device used to take a "bite" out of the lake bottom. Used to collect bottom material or benthos.
PORTSIDE - When facing the front (bow) of the vessel, the left side.
PRECISION - Degree of variation among a set of repeated measurements obtained under similar conditions.
PRODUCER - An organism such as a plant which makes its own food through the process of photosynthesis.
RADAR - Use of radio waves to provide information about objects on or above the surface of water; RAdio Direction And Range.
SAND DUNES - Mounds of sand created by wind picking up sand and depositing it when an obstacle is encountered.
SEASONAL TURNOVER - A change in a lake that usually occurs in spring and fall when more dense, cooler or heavier surface water sinks forcing warmer and less dense bottom water upward. This results in a stirring and mixing of nutrients.
SECCHI DISK - A small (20 cm) disk which is used to measure the transparency of water. It is lowered into the water until it is no longer visible.
SEDIMENT - Materials such as soil, sand, and silt that are washed from land into water, usually after rain. The particles are deposited in areas where the water flow is slowed such as in harbors, wetlands, and lakes.
SIDE DECK - The right (starboard) or left (portside) passage from the front (bow) to the back (stern) on the vessel; off limits.
SOLUBILITY - The relative ability of a substance (solid or gas) to dissolve in water or another liquid.
SOLUTION - A homogeneous mixture containing two or more substances.
SOLVENT - A substance that dissolves another substance to form a solution.
SONAR - Use of sound to determine depth of water as well as direction and distance to underwater features; SOund Navigation And Range.
STANDARD - A prepared sample with a known value.
STARBOARD - When facing the front (bow) of the vessel, the right side.
SUSPENSION - A mixture in which very small particles of a solid remain suspended without dissolving.
THERMAL STRATIFICATION - Separation of water into different temperature layers. Upper layer: EPILIMNION, middle layer: THERMOCLINE, and bottom layer: HYPOLIMNION.
THERMOMETER - Used to determine temperature. May be calibrated in the Celsius and/or Fahrenheit Scale. For scientific purposes, the Celsius Scale is used.
TITRATION - The addition of small, precise quantities of chemical to a sample until an endpoint such as a color change is reached. The dissolved oxygen test involves a titration procedure using a digital titrator to add drops of a chemical to the water sample.
TRANSPARENCY - The depth that light will penetrate water. A Secchi disk is used to measure the limit of visibility in water bodies such as lakes.
TRIBUTARY - A stream or river that flows into a larger stream, river, or lake.
TURBIDITY - A measure of how particles suspended in water affect its clarity. Microorganisms, soil particles, plankton, or other organic/inorganic matter causes the cloudy or muddy appearance of water.
TURBIDITY METER - An instrument used to measure water clarity as related to light scattered by particles suspended in water. Light scattered by the suspended material is detected by a photocell. The photocell converts the scattered light into an electrical current that is sent through the meter producing a numerical reading in NTUs.
VAN DORN SAMPLING BOTTLE - A plastic cylinder with stoppers at each end that is used to collect water samples at various depths.
WATER COLOR SCALE - A number of standard colors (the Forel-Ule Scale) compared with lake water. The resulting number is related to water quality, dissolved or suspended matter, and biological productivity.
WATER COLUMN - Vertical arrangement of water from the surface to the bottom of a water body.
WATER CYCLE - Movement of water from the air to land and water and back to the air. Evaporation, transpiration, condensation, infiltration, and runoff are all parts of the water (hydrologic) cycle.
WATER QUALITY - The physical, chemical, and biological characteristics of water as they relate to the use of the water.
WATER SAMPLERS - Metal or plastic cylinder-shaped containers with stoppers at each end used to collect a sample of water at selected depths or at the water's surface. Van Dorn bottles, and less frequently, Kemmerer water samplers, are used on the vessels.
WATERSHED - The land area in which water drains toward a lake, stream, or river at a lower elevation.
WINCH - An electric powered hoist used for lowering and raising sampling equipment. The winch line is also called the hydrographic wire. VERY DANGEROUS. HANDS OFF.
YELLOW LINES - Warning marks on the aft (rear) and side decks of the vessels over which passengers are NOT to step unless with an instructor.