This interactive explores the sequential and interlinking science concepts that underpin knowledge and understanding about habitat1 interactions in Aotearoa2 New Zealand’s beach environments.
The concepts listed just above the overarching concepts reflect learning at New Zealand Curriculum level 1 and show how they may build in sequence to levels 2–3. The overarching science concepts are fully developed concepts and might not be achieved until level 7 or 8.
The text is courtesy of the New Zealand Ministry of Education’s Building Science Concepts Book 21 Life between the Tides: Sandy Shores, Mudflats, and Rocky Shores. The links to Hub resources provide additional background information and classroom activities that will support teachers to scaffold the development of their students’ conceptual understanding about life between the tides. The images provide a means to initiate discussions, check student thinking and consolidate student understanding.
To use this interactive, move your mouse or finger over any of the green labelled boxes and select to obtain more information.
Download a PDF file of the transcript here.
The article Building Science Concepts: Life between the tides provides additional science and pedagogical information.
The concepts introduced here are developed further in Building Science Concepts: Tidal communities which explores the overarching concepts for levels 3 and 4.
Interactive background image courtesy of Anne Barker.
Transcript
The beach provides each type of living thing found there with food and shelter
All the living things that make their homes at the beach rely on that environment for their basic needs – food and shelter.
Plants and their food
Through the process of photosynthesis3, plants in the water, as on land, produce their own food in the form of starches and sugars, so they are called producers. They can access carbon dioxide4 for photosynthesis and oxygen5 for respiration6 from the water.
Animals and their food
Herbivorous and carnivorous animals are part of a group of animals known as consumers. Their food webs begin with the plants of the ocean; microscopic algae7 such as phytoplankton8. Zooplankton9 graze on this ‘pasture of the sea’. These two forms of plankton10 form the basic food for all beach community animals.
A place to live
Plants and animals at the beach, like living things everywhere, need shelter to survive. A range of environmental factors make life at the beach challenging: wave action, tide, drying effects of the Sun, wind, particles of salt, periodic covering and uncovering by water and changing salinity11 levels, not to mention predators.
Their shelter is a combination of their physical surroundings and the protective mechanisms they have developed that suit these conditions12. Their shelter must be located near their food, so each type of living thing tends to live in a defined habitat in a specific zone on the beach.
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- Marine habitats
- Habitats in the Bay of Plenty
- Life on a reef
- Adapting to marine habitats
- Catch my drift
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Image: Intertidal13 zone, Auckland Island, Dr Rebecca McLeod.
Some beaches have a greater variety and number of organisms living there than other beaches
Some beaches offer generally much harsher conditions for plants and animals to live in than others. There tends to be many more different species14 in a beach with rock pools (hāroto) than on an open sandy beach. All living things found in each of the beach zones have adaptations15 that enable them to survive in that habitat.
The intertidal zone
All living things found in the area between the tides need to adapt to variations caused by tides, weather16, sea conditions and varying degrees of exposure to:
- wind and Sun
- temperature17 change
- coverage by water
- varying mixtures of freshwater and saltwater
- varying salinity (for example, evaporation18 in rock pools)
- predators from the sea when the tide is in and from the land when the tide is out
- abrasion from sand moved by wind or water
- the movement of water from waves and tides.
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Image: Low tide at Twelve Mile Beach near Greymouth, petervick167, 123RF Ltd.
There are many kinds of living things at the beach
In spite of the range of conditions at beaches, there is an amazing biodiversity19 present. Living organisms have adapted20 to and colonised every available ecological niche21.
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Image: Stalk-eyed mud crab, Public domain.
Changes to the beach may affect the ability of living things found there to obtain food and find shelter
The beach environment undergoes not only the diverse regular daily and seasonal changes of conditions but also the unpredictable changes due to extreme weather, unusual tides and the impact of people.
Water and wind are two of the most powerful agents of change in nature, and their effects are readily seen on all beaches. Waves can move great quantities of beach material such as sand and shingle and wear away cliffs and rock. Wind can create and reshape sand dunes (tāhuahua). Like waves, wind can also wear away cliffs and rock and even uproot seaside plants.
Change can come from the land as well as the sea. Flood events can send huge amounts of water down rivers, carrying debris such as trees, branches and silt22 downstream. If this material builds up in estuaries23, the river’s course can change, leaving tidal mudflats high and dry. The debris left over from logging operations known as slash causes many problems for the inhabitants of river valleys and the seashore.
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Image: Pollution from the Fox Glacier landfill being washed down the Fox River and along the coast, DOC, CC BY 4.0.
Every beach has a range of habitats, and different kinds of living things can be found in each habitat
New Zealand beaches include a variety of distinct habitats24, each supporting a wide range of living things. All beaches share several characteristics:
- Land forming their shores – hard, such as cliffs and rocks, or soft, such as sand or mud.
- Presence of water – saltwater or a combination of saltwater and freshwater in mudflats and estuaries.
- Tides (tai) – regularly fluctuating levels of water.
Within each habitat, there are a range of conditions to be found with specific adaptations needed by the inhabitants in order to survive.
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Image: Ngarimu Bay, Anne Barker.
There are various kinds of beaches, and the way they look is constantly changing
The three main types of beach considered here are:
- rocky shores
- flat, sandy (and shingle) beaches
- mudflats in lagoons and estuaries.
Many of the beaches in Aotearoa New Zealand are made up of more than one of these types or variations of them.
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- Monitoring rocky shore communities
- Mt Maunganui surf beach
- Mangroves act as a buffer(mudflats)
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Image: Piha Beach, Aleksei Potov, 123RF Ltd.
Acknowledgment
This resource is a partial replication of the New Zealand Ministry of Education’s Building Science Concepts Book 21 Life between the Tides: Sandy Shores, Mudflats, and Rocky Shores.
- habitat: The natural environment in which an organism lives.
- Aotearoa: The Māori name for New Zealand, meaning Land of the Long White Cloud.
- photosynthesis: A process that uses the energy from sunlight to convert carbon dioxide and water into carbohydrates, releasing oxygen as a byproduct. Photosynthesis occurs in the green parts of plants, in algae and in some microorganisms.
- carbon dioxide: CO2 is a colourless, odourless, incombustible gas. It is a product of cellular respiration and combustion and is an essential component in photosynthesis.
- oxygen: A non-metal – symbol O, atomic number 8. Oxygen is a gas found in the air. It is needed for aerobic cellular respiration in cells.
- respiration: Can mean either cellular respiration (the process by which cells create energy) or gas exchange (breathing).
- algae: A large, diverse group of photosynthetic eukaryotic organisms. Algae have no stems or leaves and grow in water or on damp surfaces.
- phytoplankton: Very small plant organisms that drift with water currents and, like land plants, use carbon dioxide, release oxygen and convert minerals to a form animals can use.
- zooplankton: Tiny shrimp-like animals that drift with water currents.
- plankton: A group of marine organisms including single-celled and multi-celled organisms.
- salinity: The amount of chemicals dissolved in water. In seawater, the main chemical is sodium chloride (salt), but there are many others in smaller quantities.
- condition: An existing state or situation; a mode or state of being.
- intertidal: Marine habitats that are above the water at low tide and below the water at high tide.
- species: (Abbreviation sp. or spp.) A division used in the Linnean system of classification or taxonomy. A group of living organisms that can interbreed to produce viable offspring.
- adaptation: A change in the structure or function of something. In biology, a change in a species, as a result of natural selection. Individuals with a particular feature (adaptation) are more likely to survive and reproduce than individuals without this feature.
- weather: Daily or short-term conditions like temperature, cloud cover, precipitation and wind affecting a certain area.
- temperature: A measure of the degree of hotness or coldness of an object or substance. Temperature is measured with a thermometer calibrated in one or more temperature scales. Kelvin scale temperature is a measure of the average energy of the molecules of a body.
- evaporation: The process by which a liquid is converted into a gas, without necessarily reaching the boiling point.
- biodiversity: The range of species found in a particular region. The more species that exist (the higher the biodiversity), the more likely it is that an ecosystem will survive episodes of change.
- adaptation: A change in the structure or function of something. In biology, a change in a species, as a result of natural selection. Individuals with a particular feature (adaptation) are more likely to survive and reproduce than individuals without this feature.
- niche: The position occupied by an organism in an ecosystem. The niche includes both the organism’s specific physical environment and the role that it plays within the wider ecosystem.
- silt: A granular material of a size somewhere between sand and clay. Its mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in water. It may also exist at the bottom of a water body.
- estuary: A partially enclosed body of water where freshwater mixes with saltwater from the sea.
- habitat: The natural environment in which an organism lives.
