Post-Little Ice Age evolution of Svalbard's lagoon systems – types, changes, and responses to storms

Lagoon coasts are regarded as among the most vulnerable ecosystems to the effects of climate change, serving as conduits for interconnectivity between terrestrial, marine, and atmospheric systems. The stability of lagoons is contingent upon several factors, including the influence of storm waves, ocean currents, sediment supply, and sea level changes. To date, however, little research has been conducted on the processes shaping the evolution of Arctic coastal lagoon systems (Smith et al., 2020). The present study utilises a comprehensive array of remote sensing data sources, encompassing aerial photographs from the 1930s, orthophotographs from 1936–1938, and satellite imagery from 2021, to identify lagoon formation and systematically classify their typology.

The construction of a database comprising over 430 lagoons revealed that at least 98 of these were formed after 1936, with eight disappearing within a century. Since the end of the last ice age (LIA), at least 98 new lagoons have been formed, resulting in the current Svalbard coastal environment comprising 434 lagoons spanning 147 km². A new lagoon type currently rapidly forming across the archipelago, is the moraine-controlled paraglacial lagoon. These lagoons form as a consequence of glacial retreat and subsequent inundation of the area between moraines and glacier ice-cliffs by the sea. The majority of observed lagoons are characterised by resistant barriers capable of withstanding strong storms. In general, the factors controlling the stability of Svalbard lagoons remain poorly understood. This is partly due to the fact that permafrost has not yet been thoroughly studied in the area and partly due to the fact that the distribution of sub-lagoon permafrost is not yet fully understood.

Keywords: lagoon systems, moraine-controlled paraglacial lagoons, coastal change,
glacier retreat, Svalbard, Arctic.

Funding: This research was funded in whole by the National Science Centre in Poland (project: Arctic storm impacts recorded in beach-ridges and lake archives: scenarios for less icy future “ASPIRE” – UMO-2020/37/B/ST10/03074)