The Lake Book

LAKES ARE LIVING ECOSYSTEMS
Organisms that live in lakes—from microscopic algae to top predators
such as loons—interact with many forces, including wind, sunlight, rain,
snow, nutrients, oxygen, temperature, and alkalinity to create vibrant,
balanced, but ever-changing ecosystems. Without people, homes, and
roads in a watershed, a lake’s water quality is determined only by the
interactions among the many living and non-living parts of a lake
ecosystem.
Maintaining a healthy population of microscopic organisms (including
plants such as algae that use the sun to produce energy and animals
such as copepods and daphnia that eat plants or other animals to
survive) is the basis for a balanced food web. These tiny creatures feed
on larger animals who feed on even larger animals in and around the
lake. Keeping the food web in balance, with enough (but not too much)
food for plants and animals that live there is key to long-term lake health.
Wind and wave action
re-oxygenate surface
waters.
Sunlight and nutrients
stimulate growth of algae.
Many fish need cool,
oxygen-rich waters.
Loons are top
lake predators,
eating almost
exclusively
fish.
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