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  • The ocean has an amazing diversity of habitat types and species that live within them.

    Ocean habitats are formed in two ways – from living organisms and from physical features such as sand, mud or rocks. Discover how marine habitats are classified and learn about some of their particular features.

    To use this interactive, move your mouse or finger over any of the labelled boxes and click to obtain more information.

    Background image: NIWA CC BY 3.0

    Transcript

    Classifying marine habitats

    Just as there are different types of habitats on land, the ocean also has an amazing diversity of habitat types and species that live within them. A habitat can be the size of your backyard or big enough to cover hundreds of kilometres of ocean. It all depends on the unique conditions and features of that area.

    In our oceans, habitats are formed in two ways – from living organisms and from physical features such as sand, mud or rocks. They extend from the seashore all the way to the deepest parts of the open ocean.

    We classify them according to the combination of different factors – ocean depth, the intensity of currents and waves and the type of seafloor (such as coarse sand or mud). Each combination of factors forms a unique type of habitat that supports many levels of life from the smallest invertebrates to taonga species like tuna (eel) to commercially important species like snapper.

    Download the Department of Conservation infographic as a PDF.

    Physical marine habitats

    Any given habitat type will have a range of different infaunal (under the seafloor), epifaunal (on the seafloor) and water column (above the seafloor) creatures within it. For instance, a sandy seafloor habitat may have burrowing snails and amphipods, while rays and eels may shallowly bury themselves in the sand for protection or to hunt prey. 

    The type of sediments found in an area will depend on the level of energy in the surrounding waters. Strong currents and waves are capable of moving small stones and pebbles, which will wash away. In places where wave and current energy is low and water is slow moving, such as estuaries or sheltered bays, sediments settle and accumulate the smaller particles and so have muddy or silty bottoms.

    Download the Department of Conservation infographic as a PDF.

    Copyright: Department of Conservation

    Biogenic engineers and architects

    The habitats created by living organisms are called biogenic – ‘bio’ means life and ‘genic’ means formed by. Biogenic habitats are those made from living things (such as kelp forests) or from the activities of plants, animals or other organisms (like the burrows that a crab makes).

    On land, the mighty kauri tree could be considered a biogenic habitat. The tree itself is a living organism, which provides habitats for birds, insects, ferns and fungi. 

    This is the basis of biogenic communities – one type of organism provides the structure for many other organisms to live. 

    In the ocean, kelp forests play a similar role. These biogenic habitats are like underwater cities with different species living together in thriving communities. You could think of biogenic organisms as the architects and construction workers who turn the basic materials of the seafloor into living cities.

     A few individual organisms do not form a functional biogenic habitat. The real value for species, conservation and fisheries comes from the ability for these plants and animals to form large, biogenic habitats.

    The organisms that create these habitats are crucial for maintaining healthy oceans, rich with many types of life. They engineer the areas around them to support other species and make valuable resources available, such as oxygen and nutrients.

    Download the Department of Conservation infographic as a PDF.

    Copyright: Department of Conservation

    Biogenic habitats

    Biogenic habitats perform many crucial functions that we also rely on as humans. 

    Kaimoana
    Some, such as kuku and tuangi (New Zealand cockle), are harvested as traditional kaimoana (seafood) or commercial fisheries species. Others provide nursery sites for young fish such as snapper and moki. 

    Filtering the water column
    Many species forming biogenic habitats (sponges, shellfish, tube worms) filter the water column, removing excess nutrients and transferring sediments from the open water to the seafloor.

    Seafloor engineering
    Much like land plants, which stabilise soil with their roots to control erosion, larger biogenic organisms stabilise the seafloor. Silt, mud and rocks aren’t very hospitable to many species, but pioneering species like seagrasses and hururoa (horse mussels) happily settle on these sediments, providing structure for other species to make their homes.

    Creating habitats for other species
    These 3D structures become habitats for invertebrates, fish and shellfish, which in turn feed seabirds and large marine mammals like fur seals.

    New Zealand waters host a myriad of biogenic habitats
    These include kelp forestsmangroves, seagrass beds, kuku beds, sponge gardens and bryozoan beds.

    Download the Department of Conservation infographic as a PDF.

    Copyright: Department of Conservation

    Habitats differ by depth

    We classify habitats according to the combination of different factors. This includes ocean depth, the intensity of currents and waves and the type of seafloor (such as coarse sand or mud). 

    Each habitat has a distinct set of factors that make it a unique area. These areas support many levels of life. This can be from the smallest invertebrates to taonga species like tuna and commercially important species like snapper. 

    In the oceans, environmental conditions vary greatly by depth, so depth also plays a role in species distribution. The deeper you go, the less light there is, the colder it gets and the higher the pressure.

    Download the Department of Conservation infographic as a PDF.

    Copyright: Department of Conservation

    Habitats differ by wave exposure

    Within a small distance, habitats can vary greatly. If there are differences in wave actions or speed of current, it will create a different habitat, inhabited by different species.

    Download the Department of Conservation infographic as a PDF.

    Copyright: Department of Conservation

    Acknowledgment

    This resource is another great collaboration between the Department of Conservation and the SLH. Infographics and text are supplied by DOC.

    Rights: The University of Waikato Te Whare Wānanga o Waikato Published 18 May 2021 Size: 4.2 MB Referencing Hub media
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