Map of the Week – Marine sediment extraction
Did you ever wonder where the sand on the beach comes from? It is the result of the continuous weathering and disintegration of mountains and rocks over millions of years. As larger pieces of rocks are transported from the hinterland by rivers and streams, they gradually get broken down to gravel, sand and subsequently even finer types of sediment like silt and clay. Eventually, this material makes its way to the seas and ocean, where it is deposited at the seafloor together with shells, skeletal fragments and other detritus of biological origin to form marine sediments.
These sediments, commonly called aggregates, provide a crucial natural resource for a variety of industrial, and wider societal, applications. Sand and gravel are the main ingredients to make concrete, the most used construction material to date, required for the construction of roads, housing and other infrastructure. Sand is also important to restore and protect beaches from coastal erosion caused by storms and flooding, a process called beach nourishment. And, with increasing global urbanisation together with increasing coastal erosion due in part to rising sea levels, it is no surprise that aggregate demand has increased three-fold (up to 40-50 billion tonnes per year) over the last two decades. Unfortunately, as this growing demand is depleting existing aggregate resources, there is an increase in illegal and unsustainable sand extraction in the marine environment with potentially far-reaching environmental and social consequences.
In Europe, the ICES Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem (WGEXT) is researching the effects of marine sand and gravel extraction to ensure these resources are sustainably managed and mitigation measures are adopted, where required. The map of the week shows the locations in European waters where marine sediments are extracted as well as the end-use of the extracted material.
The data in this map are provided by EMODnet Human Activities.