Galactic Hot Dogs
 

ALGAE

Algae are simple organisms that make food from sunlight by photosynthesis, but lack the roots, stems, and leaves of proper plants. Algae are found in all water environments, and some can live on land, forming a thin, greenish layer on damp surfaces. Algae make up most of the oceans’ PHYTOPLANKTON – microscopic life forms photosynthesizing at the ocean surface. Larger marine algae called seaweeds are made of many cells, with structures called fronds that look similar to plant leaves.

FOREST OF KELP

Kelps are varieties of large, dark green or brown seaweeds that grow in cold seas around the world. One type, called giant kelp, can reach up to 60 m (196 ft) from seabed to surface. Giant kelp can form magnificent underwater forests. Kelp beds provide an important habitat for other marine life, including snails, crabs, sea urchins, seals, and sea otters.

TYPES OF SEAWEED

All seaweeds contain green chlorophyll for photosynthesis, but some types have extra pigments which make them appear brown or red. Different seaweeds survive at different tidal zones on the seashore – the longer they can survive being exposed by the tides, the higher up the beach they can live.

ALGAL OVERKILL

Lakes, ponds, and ditches can be smothered by algal growth when there are too many nutrients in the water. Thick layers of algae cover the water’s surface, cutting off sunlight to the plants and algae below and killing them. As these organisms rot, oxygen in the water is used up, and much of the life below the water’s surface dies.

PHYTOPLANKTON

Microscopic algae that float in the oceans, using the energy of sunlight to make food and grow, are called phytoplankton. Together with zooplankton – tiny animals and animal-like organisms – they float near the water’s surface. In the right conditions, phytoplankton can multiply rapidly, turning water green or red. They are the ultimate source of food for almost all marine life.

POISONOUS RED TIDES

Algal blooms can happen in the sea when nutrients such as fertilizers or sewage make life too easy for phytoplankton. Algae such as Noctiluca scintillans can turn the sea red, poisoning animals such as shellfish with toxins which would normally be more dispersed. Noctiluca means “night light” – this phytoplankton can glow in the dark, creating flickers of light on the sea’s surface.

FIND OUT MORE

Oceans
Photosynthesis

Copyright © 2007 Dorling Kindersley

highlights

Teens and E-Cigarettes: 6 Things You Must Know
For the first time in a generation, tobacco use has risen among the nation's youth, due to the rising use of e-cigarettes. Learn more about the dangerous and addictive e-cigarette trend, and get tips to talk to your teen.

Find Today's Newest & Best Children's Books!
Looking for newly released books for your child? Try our new Book Finder tool to search for new books by age, type, and theme, brought to you by Galactic Hot Dogs.

Printable Lists of the Top 100 Baby Names
Need help with baby name ideas? Use our printable list of the top 100 girl names and top 100 boy names of 2015 to help you brainstorm and narrow down your favorites.

Registered for Kindergarten — Now What?
Wondering what to do now that you've signed your child up for kindergarten? Try our award-winning Kindergarten Readiness app! This easy-to-use checklist comes with games and activities to help your child build essential skills for kindergarten. Download the Kindergarten Readiness app today!

stay connected

Sign up for our free email newsletters and receive the latest advice and information on all things parenting.

Enter your email address to sign up or manage your account.

Facebook icon Facebook icon Follow Us on Pinterest

editor’s picks