WASHINGTON (Reuters) - There are more than 210,000 known life forms in the world's oceans, but this could be a fraction of the total number of marine species, according to early results from a marine census released on Thursday. Scientists from around the world are expected to complete the census of the world's oceans by 2010, when they hope to have a better understanding of the waters that cover nearly 70 percent of the Earth's surface. With nearly half of the world's population of 6.3 billion living along ocean coasts, experts say the big deep has been under-explored. "The census...