Recent macroscale research has shown that the increase in regional sea temperatures has triggered a major re-organisation in calanoid copepod species composition and biodiversity over the whole North Atlantic basin. During the last 40 years there has been a northerly movement of warmer water plankton by 10° latitude in the north-east Atlantic and a similar retreat of colder water plankton to the north. This geographical movement is much more pronounced than any documented terrestrial study, presumably due to advective processes (see biogeographic case-study below). Over the last decade there has been a progressive increase in the presence of warm-water/sub-tropical species into the more temperate areas of the north-east Atlantic.

In terms of marine phenological changes and climate, the plankton of the North Sea has been extensively studied using Continuous Plankton Recorder data. Using 66 taxa it was found that the plankton community was responding to changes in SST by adjusting their seasonality (in some cases a shift in seasonal cycles of over six weeks was detected), but more importantly the response to climate warming varied between different functional groups and trophic levels, leading to mismatch. It is thought that temperate marine environments are particularly vulnerable to phenological changes caused by climatic warming because the recruitment success of higher trophic levels is highly dependent on synchronisation with pulsed planktonic production. The rapid changes in plankton communities observed over the last few decades in the North Atlantic, related to regional climate changes, have enormous consequences for other trophic levels and biogeochemical processes. See phenology case-study below.