Part 2: Biotic Indicators Fresh Water Studies: Water Quality & Living Organisms

How do abiotic factors affect freshwater organisms? Temperature

How do abiotic factors affect freshwater organisms? Optimal Temperature Range OrganismTemp(°C) Trout5-20 Smallmouth Bass5-28 Caddisfly larvae10-25 Mosquito larvae10-25 Carp10-25 Catfish20-25 Temperature

How do abiotic factors affect freshwater organisms? Dissolved Oxygen

How do abiotic factors affect freshwater organisms? Dissolved Oxygen Minimum DO Requirements OrganismDO (mg/l) Trout6.5 Smallmouth Bass6.5 Caddisfly larvae4.0 Carp2.0 Catfish2.5 Mosquito larvae1.0

How do abiotic factors affect freshwater organisms? pH

How do abiotic factors affect freshwater organisms? pH Effects of pH on aquatic life pH___________Effect__________________ All fish, most frogs, insects absent Bacteria die. Detritus accumulates, locking up essential nutrients Optimal for most organisms Rapidly lethal to all species of fish

How do abiotic factors affect freshwater organisms? Total Dissolved Solids (TDS)

How do abiotic factors affect freshwater organisms? Total Dissolved Solids (TDS) Natural TDS come from rocks and soil from the watershed that drains into the stream, river, pond or lake. Changes in TDS can indicate a problem. If salts are high, dehydration occurs. Solids cause a laxative effect. Dissolved minerals can affect the pH, raising or lowering depending on the ions present. Range: mg/l

How do abiotic factors affect freshwater organisms? Turbidity

How do abiotic factors affect freshwater organisms? Turbidity High turbidity decreases sunlight which decreases the rate of photosynthesis. Water that is highly turbid will warm faster, decreasing the dissolved oxygen available for respiration of all organisms.

Photo: M.B. Elder

Tier 0: The Sun

Tier 1: Pytoplacton & Plants Tier 0: The Sun

Tier 1: Pytoplacton & Plants Tier 0: The Sun Tier 2: Zooplankton & Insects

Tier 1: Pytoplacton & Plants Tier 0: The Sun Tier 2: Zooplankton & Insects Tier 3: Crustaceans, Insects, Mollusks, Small Fish

Tier 1: Pytoplacton & Plants Tier 0: The Sun Tier 2: Zooplankton & Insects Tier 3: Crustaceans, Insects, Mollusks, Small Fish Tier 4: Smaller Fishes

Tier 1: Pytoplacton & Plants Tier 0: The Sun Tier 2: Zooplankton & Insects Tier 3: Crustaceans, Insects, Mollusks, Small Fish Tier 4: Smaller Fishes Tier 5: Predatory Fishes

Tier 1: Pytoplacton & Plants Tier 0: The Sun Tier 2: Zooplankton & Insects Tier 3: Crustaceans, Insects, Mollusks, Small Fish Tier 4: Smaller Fishes Tier 5: Predatory Fishes Tier 6: Top Predators

Includes Insects Crustaceans Mollusks

Sensitive to Changes Cannot easily escape changes Collected very easily

What do macroinvertebrates do? JobExample Predatorsdragonfly, damselfly, beetles Filter feedersmussels, fly larvae, midge larvae Scraperssnails, mayfly larvae Collectorsworms, planarians Shreddersamphipods, caddisfly larvae

Group A: Very sensitive to Environmental Stresses StonefliesMayfliesCaddisfliesDobsonfliesWater penny Group B: Somewhat sensitive to Environmental Stresses DragonfliesCranefliesDamselfliesCrayfishScuds Group C: Tolerant to Environmental Stresses Midges LeechesSnailsPouch SnailsBlackfly larva

Conclusion: Freshwater organisms-the Biotic part of the Freshwater environment- have “Limits” or “Optimal ranges” in water quality where they prefer to live. The quality of water can be determined by what and how many organisms are living in that environment. Macroinvertebrates are used to evaluate the quality and history of the water environment.

Image credits-Used with permission 1-17R.B. Elder 18-25Norbert Hamm 26-32Norbert Hamm