|Invisible barriers to dispersal|In: Science (Washington). American Association for the Advancement of Science: New York, N.Y. ISSN 0036-8075, more
Climate change is causing organisms to migrate into new geographic areas, with most organisms tracking the movement of suitable temperatures poleward. The movements appear to be more rapid for marine than for terrestrial fauna, perhaps because marine organisms have fewer barriers to dispersal , but many marine organisms do encounter barriers that inhibit their ability to colonize new habitats. On page 1135 of this issue, Muir et al. show that low wintertime irradiance limits the poleward expansion of staghorn corals. On page 1132, Deutsch et al. identify another barrier to marine species: the ratio of oxygen supply and metabolic demand, which determines in which parts of the ocean fish and invertebrates have enough oxygen to support their metabolic needs. These two studies remind us that climate change will reshape marine species habitats but not necessarily expand them.