Aboard the Melinda Ann: Glossary

• Algal bloom: a sudden excessive growth of algae, usually prompted by an influx of phosphorus
• Benthic dredge: a clam-like tool used to trap a sample of lake sediment and bring it to the surface for examination
• Biodiversity: the variety of plant and animal life in a habitat or ecosystem
• Clarity: clearness or quality of water that makes it lucid; opposite of turbidity
• Dissolved oxygen: oxygen gas dissolved in water
• Epilimnion: the topmost layer in a water column, characterized by warmer temperatures and higher dissolved oxygen in the summer
• Food chain (web): a series of organisms (plant and animal) all dependent on the next as a source of food
• Hypolimnion: the bottom layer in a water column, characterized by colder temperatures and little dissolved oxygen in the summer
• Macroinvertebrates: organisms that lack backbones and are large enough to be observed without the aid of a microscope
• Mixing: flow of water from one layer in the water column to another; caused by wind, waves, and photosynthesis
• Phosphorus: a nutrient that naturally occurs in lake and soil sediments, limiting factor in the growth of algae
• Photosynthesis: process which plants, like phytoplankton, undergo that uses sunlight to convert carbon dioxide and water to food
• Phytoplankton (algae): plankton consisting of microscopic plants
• Plankton: small, often microscopic, plant and animal organisms found floating in fresh water; antagonist of ‘Spongebob’
• Plankton net: a tool used to collect zooplankton for examination
• Remote operated vehicle (ROV): electrically-powered instrument that is steered through a lake on a tether with an attached camera
• Secchi depth: bottom depth at which light can penetrate through a water column, measured with a Secchi disk
• Sediment: materials that settle to the bottom of the lake, including tree litter, dead aquatic plants and animals, and soil
• Silt: fine sand and clay that is carried into a lake by runoff and becomes part of the lake sediment
• Stormwater runoff: water that collects on land and carries soil sediment as it flows into a lake or stream
• Strata: layers within the water column with varying characteristics, like temperature, dissolved oxygen, and fluorescence
• Stratification (layering): process by which deep lakes form layers by depth with varying characteristics
• Temperature probe: a specialized thermometer on a tether that is used to measure changes in temperature in a body of water
• Thermocline: a single layer between the top (warm) and bottom (cold) layers in a lake, defined by a dramatic temperature gradient
• Transparency: ability of water to allow light to pass through it
• Turbidity: cloudiness or obscurity of water; opposite of clarity
• Turn over: process by which the surface and bottom water in a lake are the same temperature, causing all layers to mix and become relatively uniform in terms of temperature, amount of sediments, and dissolved oxygen
• Vegetative buffer: a wide strip of vegetation along the shore of a lake that filters stormwater before it reaches the lake and removes phosphorus
• Water column: an imaginary ‘column’ of water extending from the surface to the bottom sediment
• Zooplankton: plankton consisting of microscopic animals