ABSTRACT
Water covers more than 70% of the surface of the earth and oceans hold about 96.5% of this water. This leads to a great environmental diversity resulting from the very different physical and chemical conditions throughout the body of water. There is a vast number of eukaryotic organisms, and though more than 212,000 species have been accepted according to the World Register of Marine Species (WoRMS), it is estimated that this number only accounts for a quarter of the estimated 0.7 million to 1 million marine species,1 or even less if considering other predictions of a total 2.2 million species.2 According to WoRMS, the amount of described and accepted species increases by about 2000 per year, revealing the great interest in exploring this environment.
