ulva lactuca or sea lettuce seaweed attached to rocks

seaweed ulva lactuca sea lettuce edible green alga ulvaceae atlantic ocean iodine source treat goitre deficiency magoito beach portugal travel maritime sao joao das lampas lisbon sintra low tide mussels attached marine life closeup surface protist algae thin flat discoid holdfast soft translucent background high level nitrates dangerous fumes macro rich waters eroded rocks holes