Where marine iguanas feed on seaweed?

marine iguana
A marine iguana grazes in seaweed
   A prehistoric-looking lizard hauls itself from the water of a rocky inlet and blows a shower of salty water vapour out through its nostrils. It is a rare marine iguana, about 4ft (1.2m) long, found only in the Galapagos Islands, which are in the Pacific west of Ecuador.
   Marine iguanas are the only lizards to feed in the sea. They bask on the shore to warm up their bodies and then, propelling themselves with their flattened tails, swim down 50ft (15m) or more to feed on seaweeds such as sea lettuce growing on the rocks on the sea floor. While they are underwater they cannot breathe, but they conserve oxygen by slowing down their heart rate, so reducing their blood flow. When they come up to breathe, they also expel excess salt taken in while eating underwater. They have glands in their nostrils for excreting the salt.
   For marine iguanas, El NiƱo is likely to bring famine. During the 1982-83 event, when the Pacific waters warmed and the sea level rose, some of their usual grazing places were too deep to reach. And their main food plants died because of the changes in water temperature and salinity — heavy rains diluted the water. Many of the iguanas could not digest the new plants that grew in their place. On some of the islands, half the marine iguanas died and many of the survivors were dangerously underweight. While the marine iguanas suffered, their land relatives were thriving. The normally dry and dusty islands suddenly bloomed with lush plant life, and land iguanas were presented with a superabundance of food.