University of East Anglia, UK and the British Antarctic Survey
An oceanographer marvels at the good timing of shrimp.
For many marine organisms, the timing of egg hatching is key to species survival because the time window in which larvae can survive is very short. If eggs hatch too early, they starve before their food source — the spring phytoplankton — blooms. If they hatch too late, they also miss the bloom.
I’m amazed by how often nature gets things right. In most of the North Atlantic, shrimp eggs hatch just a few days before the spring bloom. Peter Koeller of the Bedford Institute of Oceanography in Dartmouth, Nova Scotia, showed that the development and hatching time of shrimp are influenced by local deep-ocean temperature (P. Koeller et al. Science 324, 791–793, 2009). This is not surprising, because eggs develop in the deep ocean and their growth rate depends on temperature.
What is surprising is that the shrimp spawn on the right day of the year across the North Atlantic, even though temperatures in the deep ocean vary from one area to the next and do not influence the timing of the spring bloom. Through evolution, the shrimp have adapted to local temperature patterns to spawn at just the right time.
However, this could prove to be a problem for shrimp and the many other zooplankton, fish and shellfish species that have adapted their spawning habits to local conditions. What will the survival rate of larvae be if deep-ocean temperatures rise, or if the spring bloom occurs earlier? How much time do organisms need to sense and adapt to such changes? These new data will help us to understand the complex interdependence of marine ecosystems, and possibly help to detect potential mismatches between egg hatching and food-source availability.