Dating girls that like ocean corals
The corals used in these studies are the ones people are most familiar with: corals that have symbiotic relationships with photosynthetic algae, which provide food in exchange for shelter, and therefore grow in shallow, sunlit, tropical waters.
We do not know whether changes in the sea surface environment increased the production of marine life, leading to more food for corals, or whether ocean circulation changes enhanced the dispersal of coral larvae.
The features of the bands themselves may reflect the condition of the ocean at the time the coral was alive and creating its skeleton.
We can look at the thickness of each band to gauge the corals’ growth rate during a given year, giving us a general sense of ocean conditions.
Like their shallow-water cousins, cold-water corals build carbonate skeletons containing geochemical traces that reflect the chemical and physical properties of the waters in which they grew.
These corals do not always accrete annual growth bands, but we know the direction in which they grow, so we can use them to create records of the deep ocean.