This lesson explains how physical landscape history and current human actions shape biodiversity in freshwater and marine ecosystems. It covers definitions and measures of aquatic biodiversity, key drivers and threats, Canadian examples, measurement methods, and practical conservation/restoration approaches.
Biodiversity in Water Systems — The Salty, the Fresh, and the Surprisingly Dramatic "If rivers carved canyons and glaciers shaped mountains, water made sure life showed up ready to party — sometimes politely, sometimes as an algal rave." You already learned how natural forces like rive...
What is biodiversity in water systems, anyway? Biodiversity = the variety of life in an ecosystem — spanning genes, species, and entire communities. In aquatic systems we measure it by species richness (how many kinds), evenness (how balanced their numbers are), and functional diversity (the rol...
Quick reminder: landscape changes set the stage Canyon and river formation creates pools, riffles, and floodplains — each micro-habitat hosts different species. Ecosystems and land development alter runoff, sediment, and connectivity (roads and dams are not the party planners you want). Future...
Marine vs Freshwater biodiversity — the headline differences Feature Freshwater (rivers, lakes) Marine (coasts, estuaries, open ocean) Salinity Low, variable High (but estuaries mix things up) Habitat size Often smaller, fragmented Generally larger, more connected Species adap...
The main drivers of aquatic biodiversity (aka the VIPs of the water world) Habitat complexity — rocks, plants, fallen logs, reefs: more nooks = more niches. Water chemistry — oxygen, pH, nutrients, and salinity determine who can breathe, eat, and survive. Flow and connectivity — rivers that co...
Real-world Canadian examples (because theory is better with drama) Great Lakes : Huge freshwater diversity but threatened by invasive species like zebra mussels, eutrophication, and shipping traffic. St. Lawrence Estuary : A mixing bowl where saltwater and freshwater meet — rich in nutrients and...
Threats to aquatic biodiversity (short, sharp, scary) Pollution (chemical runoff, plastics) Eutrophication (too many nutrients → algal blooms → oxygen death) Invasive species (zebra mussels, lampreys) crowd out natives Habitat fragmentation (dams, channelization) Climate change (temperatur...
Why biodiversity loss matters: services you actually use Clean water (thanks, filter-feeders) Fisheries (food and jobs) Flood control (healthy wetlands store water) Cultural and recreational value (places we swim, fish, and learn) Losing biodiversity is like losing tools from a survival ki...
Conservation and restoration — what actually works Protect riparian zones (vegetated buffers) to reduce runoff and cool water. Restore connectivity (fish ladders, culvert redesign, selective dam removal). Control invasive species early — prevention beats cure. Reduce nutrient runoff through ...
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