The material in this slide show is provided free for educational use only. All other forms of storage or reproduction are subject to copyright- please contact the National Marine Aquarium The slide show was designed and produced for the NMA by STEP, the Science Training & Education Partnership T raining & S cience E ducation P artnership

Plants and Light in the Ocean

Light and plant growth Light and depth in the ocean Summary How plants survive

Light and plant growth Light and depth in the ocean Summary How plants survive

Plants grow by photosynthesis They make their own food, using light and simple materials such as water

The green colour of plants is caused by chlorophyll Chlorophyll absorbs the light used in photosynthesis

Light and plant growth Light and depth in the ocean Summary How plants survive

Light is absorbed by water, so the amount of light decreases as you go deeper into the ocean

75% of the oceans are more than 3 kilometres deep Only 5% of the oceans are less than 200 metres deep

Too dark for growth surface 100 m 500 m 1000 m 3500 m Enough light here for growth

Light and plant growth Light and depth in the ocean Summary How plants survive

On land, there is usually plenty of sunlight Trees grow tall trunks so that they can stand above other plants that might shade them

In the ocean, most light disappears in the top 100 metres Plants cannot grow deeper than this

Plants growing attached to the seabed, like this kelp, can only grow where the ocean is shallow enough to let through enough light for growth

95% of the oceans are too deep for attached plants like kelp and seaweeds

In the open ocean, the most important plants are tiny algae This is a ‘diatom’ - a common type of floating alga Each cell is about 0.05 mm long - it would take 200 end-to-end to cover a distance of one centimetre

Light and plant growth Light and depth in the ocean Summary How plants survive

Plants need light in order to growLight decreases as you go deeper into the ocean You have seen that -

Most of the oceans are too deep and dark for seaweeds and kelp Plants in the open ocean are single-celled algae You have seen that -

NOTES for USERS The material in this slide show is designed to support the teaching of science at Key Stage 1 A full description of the slide show, and linked activities for students, can be found on the National Marine Aquarium (NMA) web-site: Teachers are free to amend the slide show in whatever way they feel fit, or to use slides in other contexts. However, please note that neither the NMA nor the designers will accept responsibility for modifications, and original material remains copyright of the NMA Individual images used in the slides are copyright of NMA or STEP, except where acknowledged separately The slides have been set up to display as A4 landscape format. If they are incorporated into other slide sequences with different display settings, change in aspect ratio and text location will occur The slide sequence contains the minimum of effects and transitions. However, there are some automated animations, and teachers will wish to make sure that they are familiar with the sequence before use in class Use the PowerPoint notes viewer to obtain additional information for some slides