[A - B] [C - D] [E - F - G] [H - I - J - K - L - M] [N - O] [P - Q] [R - S] [T - U - V - W - X - Y - Z]

P

parameter – A characteristic, or descriptive feature, such as odor, color, or temperature.

parasite – An organism that lives in or on another organism, causing it harm.

pathogen – A disease-producing agent, usually applied to a living organism. Generally, any virus, bacterium, or fungus that causes disease.

penetrate – To enter or force a way into; to spread or flow throughout an area.

periwinkle – Trailing evergreen plants of the genus Vinca. image

permeability – The ability of a material to allow a liquid to pass through it. Permeable materials, such as gravel and sand, allow water to move quickly through them.

pesticide – A chemical used to kill pests, especially insects and rodents.

pH – A scale from 0 to 14 used to measure relative acidity or alkalinity. A pH measurement less than 7 is acidic, 7 is neutral, and greater than 7 is basic or alkaline. image

phosphate – A form of phosphorous; an essential nutrient for plants and animals; usually present in natural waters as phosphate. Phosphate is an ion composed of one phosphorus atom and four oxygen atoms.

phosphorous – A non-metallic element designated with the chemical symbol P; an essential nutrient for plants and animals; usually present in natural waters as phosphate.

photosynthesis – A series of chemical reactions in producers, usually plants, in which light energy is used to make chemical energy in the form of food.

phytoplankton – Microscopic photosynthetic protists (i.e. bacteria and algae); form the basis of freshwater and marine food webs; the main producers in the open ocean. image

plankton – Microscopic organisms that drift freely with water currents; phytoplankton are producers; zooplankton are animals. image

pod – A seed vessel or fruit of a plant.

pollination – Sexual reproduction in plants in which pollen is transferred from anther to stigma of either the same plant or another plant.

pollution – Contamination of air, water, or soil by toxic organic or inorganic substances (e.g., industrial or agricultural waste by-products, engine exhausts, factory emissions, or human waste). Pollution can come from a single source (point-source) or be discharged over a wide area from many sources (non-point source).

point source pollution – Pollution coming from a single point (e.g., sewage-outflow pipe).

pond lily – An emergent vegetation; water lily of the genus Nymphaea; has floating leaves.

pond snails – Aquatic macroinvertebrate; phylum Mollusca, order Gastropda; organism is enclosed within one shell; tolerant of pollution. image

pool – A deeper area of water in a stream; usually quiet and often with no visible flow.

population – A group of organisms of the same species living in the same area.

porcelain-berry – Ampelopsis brevipedunculata; an exotic invasive plant that grows in intermittently flooded lowland forest. image

porosity – The percent of space or pores between sediment particles; indicates the amount of water the sediment can hold.

pouch snail – Aquatic macroinvertebrate; phylum Mollusca, order Gastropda; organism is enclosed within one shell; tolerant of pollution.

precipitation – Condensed water vapor that falls to or forms on the surface as rain, snow, hail, sleet, dew, and frost.

predator – An organism that kills and eats other organisms.

prey – A creature hunted or caught for food.

primary consumer – An organism that feeds on producers; an herbivore.

primary productivity – The amount of energy trapped by photosynthesis. This quantity determines how much life a region will support.

pristine environment – An environment remaining in a pure or uncorrupted state.

producer – An organism that makes its own food; a photosynthetic organism; an autotroph.

propagation – Increased or spread by natural reproduction.

purple dead nettle – Lamium purpureum; an exotic invasive plant that grows in a clearing (meadow or field). image

Q

Q factor – A rating scale that translates water quality test results to a number from 0-100.