decking and winter

Hi, does anyone do anything special with their decking over winter? A man who gave me lots of advice with the building of it said to keep it looking good it was best to cover it with a tarpaulin over the winter. Does anyone do this? and would that blue plastic tarpaulin do or would it have to be canvas type? Its a softwood if that makes any difference. I am guessing its to stop algal growth and maybe a bit of protection from being permanently wet?