A shortage of summer nutrients as a result of our changing climate has contributed to a 50 per cent decline in important North East Atlantic plankton over the past 60 years.
A shortage of summer nutrients as a result of our changing climate has contributed to a 50 per cent decline in important North East Atlantic plankton over the past 60 years.
New research, published in Global Change Biology, shows that larger, nutritious plankton – vital to support fish, seabirds and marine mammals – are being replaced by tiny, primary producers that are of poorer food quality.
Changes from cloudier and wetter summers to longer periods of sunshine and drought have led to decreasing iron and nutrient supply to surface waters. This results in an increased period of suboptimal feeding conditions for zooplankton at a time of year when their metabolic demand is at its highest.
In some areas, large phytoplankton are being almost completely replaced by picoplankton, especially the cyanobacterium Synechococcus, that flourishes when iron and nitrogen levels in surface waters are very low.
However, its small size and lack of essential biomolecules mean it is unable to function in the same way as larger, more nutritious phytoplankton – a vital primary producer of omega-3 – and cannot sustain shelf sea food webs efficiently.
Read more at University Of Plymouth
Image: A mixture of dinoflagellates and diatoms from the L4 coastal monitoring site off Plymouth (Credit Claire Widdicombe)
