Lecture 28- Temperate marine habitats Flashcards
What are the characteristics of temperate marine habitats?
• Low diversity • High endemism (>80% of southern marine fauna are endemic!) • 85% of fish • 90% of echinoderms • 95% of molluscs • Long history of isolation • >65 million yrs
What are some examples of temperate marine habitats?
• Seagrass meadows • Kelp forest • Sub-‐tidal rocky reefs • Soft sediments: mudflats and sandy beaches • Intertidal rocky shores
What is the distribution of marine habitats around Australia?
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What are seagrass meadows like?
-Australia has largest area of temperate seagrass -30 out of 58 worldwide seagrass species occur in Australia -Form in sheltered bays, in shallow, clear water with sandy substrate -very productive habitat (30 cm growth a day) -important nursery grounds (fish and crustaceans) -provide food an shelter -nutrient recycling -help stabilize soft sediment
What are kelp forests like?
-found in S. Aus especially Victoria and Tasmania -form in areas with rocky reefs -very productive habitats (need upwelling that is why few in australia) -kelp= brown algae -fronds can grow 50 cm a day -can grow to above 30 m -used as thickener in ice cream and jelly -provide complex habitat, shelter, and food for many species
What are temperate rocky reefs like?
-more productive than tropical reefs -in shallow water, dominated by algae (ie kelp) -in deep water, dominated by filter feeding epifauna: ascidians, sponges, bryozoans -both provide complex structure and habitat for many species -many endemic species
What are the 3 examples of sharks and rays?
- e.g Spotted wobbegong (ray): mostly hide during the day, very good at camouflaging -fiddler ray= also camouflaged ray(looks like light) -port jackson shark: has few pointy sharp teeth at the front, have bog teeth in the back to crush shells
What are the 3 habitats in temperate regions (main)?
-rocky reefs, kelp forest and seagrass
What are the characteristics of sharks and rays? (elasmobranch)
-many are endemic to australia -nocturnal carnivores (octopuses, sea urchins, molluscs, crustaceans and fish) -spend days hiding in caves or overhangs or lying half buried on sandy bottom -all good at camoouflage .spotted webbegong: has fleshy projections hanging from nostrils used in taste and feeling for prey -porzt jackson shark: specialized teeth (not serratated, front= small/ pointed and rear: broad , flat
What are he shark reproduction like?
-internal reproduction, fertilisation -many have to reach like 5 years to mature, long time to mature -low fecundity -diverse strategy -have slow reproduction -are oviporous: leathery egg cases, cork screw shape, so they drill into the sand until hatching -some egg cases are more flat and are on stones -many sharks are viviparous, have a pseudoplacenta= blood exchange between mother and young -some also ovoviparous= egge in the mother and birth,difference is that the nutrition is from the egg yolk not the mother
What are the characteristics of pipefish, seahorses and seadragons (Sygnathidae)?
-over 200 species (above 30 in temperate Australia) -some of the greatest diversity in body size and shape -micro carnivores -brooders (attached/embedded eggs, open/sealed pouch) -male parental care -eg. Leafy seadragons, weedy seadragon, ghost pipefish
What are the characteristics of the Old wife fish? (Enoplosiadae)
-monotypic family, endemic to Southern Australia (one genus) -name refers to grating sound made when stressed -poisonous first dorsal spine -black and white
What are the characteristic of Boxfishes and Cowfishes? (Ostraciidae)
-have hard bony carapace -name refers to boxy or cow like appearance -move like small submarine -fine motor control with pectoral fins -found in temperate and tropical waters
What are the characteristics of Morowongs (Cheliodactyladae)?
-center of diversity in southern australia -restricted to temperate waters -benthic micro carnivores -have large rubbery lips -very long larval stage (several moths) -peculiar juvenile stage (have papery stage, settle on reef when big, several cm)
What are the characteristics of Weedfish (Clinadae)?
-center of diversity in southern australia -experts at camouflage (look like weed, kelp) -not a lot known about them
What are the characteristics of the Handfishes (Brachionichthyidae)?
-4 species -do not have a larval stage, do not disperse very far -juveniles are like miniature adults, unusual -benthic egg layers -lack planktonic larvae stage -species in decline (loss of spawning habitat?) -found almost exclusively in Tasmania in shallow water -live in small breeding colonies -walk using modified pectoral fins
What are the characteristics of Giant Australian Cuttlefish? Sepia apama (invertebrate)
-endemic to southern Australia -largest cuttlefish in the world (50 cm long, with tentacles above a metre) -feed on small fish, crabs, and crustaceans -form hige mating aggregations in Spencer Gulf, SA, the small males who can’t mate as easily, they take on the colour of a female to sneak in (becuase only large males would normally mate) -can change colour instantly as well as shape and texture of skin
What are the characteristics of Eleven arm seastar (C. muricata)?
- largest seastar in southeastern Australia -voracious predator: eats molluscs, crabs and worms -can have 7-14 arms -can reproduce by dropping a leg
What are the characteristic of rock lobster? (predatory invertebrate)
-important commercial and recreational fishery -nocturnal predators: eat mussels, sea urchins, crabs, abalone -live in crevices and overhangs -very long larval stage
What are the characteristic of sea anemone?
-can eat a sea urchin -sit and wait predators -use stinging tentacles to capture prey
What are the characteristic of ELephant snail? (benthic hebrivore)
-scutus antipodes -very large (up to 12cm) -so called because it swings its tentacles around -related to limpets -nocturnal (hides during the day)
What are the characteristic of Blacklip abalone? (benthic herbivore)
.haliotis rubra -very important commercial fishery (and recreational) -endemic to Southern Australia -feed on drifting algae -don’t move very much
What are the characteristic of Long spine sea urchin? (benthic herbivore)
-C. rodgersii -native to NSW -when populations boom can lead to urchin barrens -range extension to Tas where it is decimating kelp (due to warming of the sea)
What are some sessile animals on rocks?
-all filter feeders -colonial ascidians -bryozoans -sponges
What are the soft sediments or Mudflats like?
-areas where low tide exposes soft mud -very fine sediment, usually anaerobic below surface -dominated by filter feeding and deposit feeding invertebrates -important feeding grounds for birds and fish
What is the soft sediment infauna and epifauna?
-the pippy: burrow in sand, sucks in water from the surface and filter it -soldier crab: deposit feeder, and moon snail (predator) -polychate worm
What are the benthic predators?
-eg. ELephant fish -feed on molluscs and worms in sediment -use their noses to detect electrical signals from moving animals in the mud
What are the temperate rocky shore like?
- dominant forces: wave action and tides -sloping shores characterised by distinct zones
- top of shore exposed to hot and dry conditions and waves
- bottom is only in exposed for short periods
- molluscs often dominate especially in upper zones
- predators, larger animals lower on the shore
What is the zonation like in the temperate rocky shores?
-characteristic zonation= gradient of dryness -splash zone (lichens, Littoria grazers) -barnacle zone (Barnacles) -Limper and mussel zone (also Galeolaria and Hormosira) -Sublitorral fringe (large algae, octopus, sea urchins and seastars)
What is the intertidal platform of the temperate rocky shores like?
-no zonation becuase it is flat -often dominated by Hormosira banksii (Neptune’s necklace) -animals protected from desiccation by algae -lots of tide pools provide diverse habitats too
What are the threats to temperate marine habitats?
-human activities (boat anchors, trampling, removal of plants and animals) -overfishing -introduced species -inputs from terrestrial runoff = sittation, toxicants, sewage, oil spills -climate change (especially sea surface temperature, sea level rise and ocean acidification)
Summary?
-habitat types: seagrass bed, kelp forest, subtidal rocky reefs, soft sediments, intertidal rocky shores -very high endemism -lower diversity than tropics -many threats (similar to tropics)
