I’m a Scientist is like school science lessons meet the X Factor! School students choose which scientist gets a prize of $1000 to communicate their work.
Scientists and students talk on this website. They both break down barriers, have fun and learn. But only the students get to vote.
This zone is the Boron Zone. It has a range of scientists studying all different topics. Who gets the prize? YOU decide!
Seagrass is the only flowering plant that can live totally submerged in water. They essentially function like terrestrial grasses except they have some structural and physiological adaptations to sea water. Ability to be salt tolerant, high light requirements, underwater pollination and seed transfer. In the tropics seagrass meadows are highly influenced by green turtles and dugongs as seagrass is their main food. The floods and cyclones of 2011 in Qld destroyed >50% of the coastal seagrass and it will take 5 to 10 years to recover.
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I’m glad Mark knew, because I didn’t!
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I think Mark can be much more informative on this one. But in general I would say that the main thing plants need to live is light, which they can get underwater just as well as they can on land.
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Plants (algae) originated in the sea more than 500 million years ago. These included single cellular plants through to some of the largest multicellular plants on the planet (e.g. giant kelp). Both types are well adapted to survival underwater – their principle requirements include light, nutrients and gaseous exchange (absorb CO2 and release O2).
Most aquatic plants are simple as they lack root systems and many other structures when compared to their terrestrial counter-parts (flowering plants). The water medium allows gaseous exchange, supports the plants, brings nutrients, however a hard substrate (e.g. rocks) is typically required for the macrophytes (large algal plants) to attach to.
Light is a limiting factor as it is quickly absorbed upon penetrating the water. This is why most plant life is found in the top 10m of the water and very little is found below 100m – where even in the clearest oceans <1% of the light penetrates.
Other plants that have returned to aquatic (underwater) environments have only partially done so –such as mangroves in marine environments and freshwater lilies, bulrushes or water hyacinth. However as Mark said the only truly aquatic flowering plants are seagrasses.
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Great answers from Mark and James – I’ve learnt something here!
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