Zofia Alicja Owczarek

As Arctic amplification accelerates glacier retreat, new dynamic landscapes are emerging at the interface of terrestrial and marine systems. This study identifies and analyses a distinct coastal landform: the Paraglacial Moraine Lagoon (PML). Formed by coastal barriers composed of terminal or lateral moraines deposited during the Little Ice Age, PMLs represent a critical yet understudied component of the glacier–climate change feedback system. Using a multi-decadal record (1936–2024) comprising aerial photography, satellite imagery, and the Digital Shoreline Analysis System (DSAS), we quantified the evolution of fourteen PML systems across the Svalbard Archipelago. Our results show that PMLs now occupy over 56 % of Svalbard's total lagoon area (ca. 83 km²), nearly triple the area they occupied in the 1930s. We identify two divergent evolutionary trajectories: (1) an erosional – fragmenting pathway (e.g., Tjuvfjordlaguna), where marine forcing leads to barrier narrowing and inlet expansion, and (2) a stabilizing – isolating pathway (e.g., Femtelaguna), where land-terminating glaciers drive rapid terrestrial sediment infilling and barrier progradation. We argue that PMLs function as essential “paraglacial sinks” trapping glaciogenic sediments and organic matter, thereby creating sheltered biodiversity hubs in otherwise harsh coastal environments. As transient features, the formation and eventual destruction of PMLs serve as a high-resolution proxy for the rapid paraglacial adjustment of polar coastlines.

As Arctic amplification accelerates glacier retreat, new dynamic landscapes are emerging at the interface of terrestrial and marine systems. This study identifies and analyses a distinct coastal landform: the Paraglacial Moraine Lagoon (PML). Formed by coastal barriers composed of terminal or lateral moraines deposited during the Little Ice Age, PMLs represent a critical yet understudied component of the glacier–climate change feedback system. Using a multi-decadal record (1936–2024) comprising aerial photography, satellite imagery, and the Digital Shoreline Analysis System (DSAS), we quantified the evolution of fourteen PML systems across the Svalbard Archipelago. Our results show that PMLs now occupy over 56 % of Svalbard's total lagoon area (ca. 83 km²), nearly triple the area they occupied in the 1930s. We identify two divergent evolutionary trajectories: (1) an erosional–fragmenting pathway (e.g., Tjuvfjordlaguna), where marine forcing leads to barrier narrowing and inlet expansion, and (2) a stabilizing–isolating pathway (e.g., Femtelaguna), where land-terminating glaciers drive rapid terrestrial sediment infilling and barrier progradation. We argue that PMLs function as essential "paraglacial sinks" trapping glaciogenic sediments and organic matter, thereby creating sheltered biodiversity hubs in otherwise harsh coastal environments. As transient features, the formation and eventual destruction of PMLs serve as a high-resolution proxy for the rapid paraglacial adjustment of polar coastlines.

As Arctic amplification accelerates glacier retreat, new dynamic landscapes are emerging at the interface of terrestrial and marine systems. This study identifies and analyses a distinct coastal landform: the Paraglacial Moraine Lagoon (PML). Formed by coastal barriers composed of terminal or lateral moraines deposited during the Little Ice Age, PMLs represent a critical yet understudied component of the glacier–climate change feedback system. Using a multi-decadal record (1936–2024) comprising aerial photography, satellite imagery, and the Digital Shoreline Analysis System (DSAS), we quantified the evolution of fourteen PML systems across the Svalbard Archipelago. Our results show that PMLs now occupy over 56 % of Svalbard's total lagoon area (ca. 83 km²), nearly triple the area they occupied in the 1930s. We identify two divergent evolutionary trajectories: (1) an erosional–fragmenting pathway (e.g., Tjuvfjordlaguna), where marine forcing leads to barrier narrowing and inlet expansion, and (2) a stabilizing–isolating pathway (e.g., Femtelaguna), where land-terminating glaciers drive rapid terrestrial sediment infilling and barrier progradation. We argue that PMLs function as essential "paraglacial sinks" trapping glaciogenic sediments and organic matter, thereby creating sheltered biodiversity hubs in otherwise harsh coastal environments. As transient features, the formation and eventual destruction of PMLs serve as a high-resolution proxy for the rapid paraglacial adjustment of polar coastlines.

As Arctic amplification accelerates glacier retreat, new dynamic landscapes are emerging at the interface of terrestrial and marine systems. This study identifies and analyses a distinct coastal landform: the Paraglacial Moraine Lagoon (PML). Formed by coastal barriers composed of terminal or lateral moraines deposited during the Little Ice Age, PMLs represent a critical yet understudied component of the glacier–climate change feedback system. Using a multi-decadal record (1936–2024) comprising aerial photography, satellite imagery, and the Digital Shoreline Analysis System (DSAS), we quantified the evolution of fourteen PML systems across the Svalbard Archipelago. Our results show that PMLs now occupy over 56 % of Svalbard's total lagoon area (ca. 83 km²), nearly triple the area they occupied in the 1930s. We identify two divergent evolutionary trajectories: (1) an erosional–fragmenting pathway (e.g., Tjuvfjordlaguna), where marine forcing leads to barrier narrowing and inlet expansion, and (2) a stabilizing–isolating pathway (e.g., Femtelaguna), where land-terminating glaciers drive rapid terrestrial sediment infilling and barrier progradation. We argue that PMLs function as essential "paraglacial sinks" trapping glaciogenic sediments and organic matter, thereby creating sheltered biodiversity hubs in otherwise harsh coastal environments. As transient features, the formation and eventual destruction of PMLs serve as a high-resolution proxy for the rapid paraglacial adjustment of polar coastlines.

As Arctic amplification accelerates glacier retreat, new dynamic landscapes are emerging at the interface of terrestrial and marine systems. This study identifies and analyses a distinct coastal landform: the Paraglacial Moraine Lagoon (PML). Formed by coastal barriers composed of terminal or lateral moraines deposited during the Little Ice Age, PMLs represent a critical yet understudied component of the glacier–climate change feedback system. Using a multi-decadal record (1936–2024) comprising aerial photography, satellite imagery, and the Digital Shoreline Analysis System (DSAS), we quantified the evolution of fourteen PML systems across the Svalbard Archipelago. Our results show that PMLs now occupy over 56 % of Svalbard's total lagoon area (ca. 83 km²), nearly triple the area they occupied in the 1930s. We identify two divergent evolutionary trajectories: (1) an erosional–fragmenting pathway (e.g., Tjuvfjordlaguna), where marine forcing leads to barrier narrowing and inlet expansion, and (2) a stabilizing–isolating pathway (e.g., Femtelaguna), where land-terminating glaciers drive rapid terrestrial sediment infilling and barrier progradation. We argue that PMLs function as essential "paraglacial sinks" trapping glaciogenic sediments and organic matter, thereby creating sheltered biodiversity hubs in otherwise harsh coastal environments. As transient features, the formation and eventual destruction of PMLs serve as a high-resolution proxy for the rapid paraglacial adjustment of polar coastlines.

As Arctic amplification accelerates glacier retreat, new dynamic landscapes are emerging at the interface of terrestrial and marine systems. This study identifies and analyses a distinct coastal landform: the Paraglacial Moraine Lagoon (PML). Formed by coastal barriers composed of terminal or lateral moraines deposited during the Little Ice Age, PMLs represent a critical yet understudied component of the glacier–climate change feedback system. Using a multi-decadal record (1936–2024) comprising aerial photography, satellite imagery, and the Digital Shoreline Analysis System (DSAS), we quantified the evolution of fourteen PML systems across the Svalbard Archipelago. Our results show that PMLs now occupy over 56 % of Svalbard's total lagoon area (ca. 83 km²), nearly triple the area they occupied in the 1930s. We identify two divergent evolutionary trajectories: (1) an erosional–fragmenting pathway (e.g., Tjuvfjordlaguna), where marine forcing leads to barrier narrowing and inlet expansion, and (2) a stabilizing–isolating pathway (e.g., Femtelaguna), where land-terminating glaciers drive rapid terrestrial sediment infilling and barrier progradation. We argue that PMLs function as essential "paraglacial sinks" trapping glaciogenic sediments and organic matter, thereby creating sheltered biodiversity hubs in otherwise harsh coastal environments. As transient features, the formation and eventual destruction of PMLs serve as a high-resolution proxy for the rapid paraglacial adjustment of polar coastlines.

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)

Barrier‐lagoon systems are among the most sensitive coastal environments, given that they accumulate the effects of environmental changes occurring on lands and in the sea. Globally, the stability of lagoons and associated barriers is controlled by the frequency and magnitude of storms approaching the coast, access to sediment supplies, and resilience to sea‐level shifts. However, the majority of studies have focused on midlatitude and tropical coastal zones, with limited insight into cold region lagoon responses. This study presents the preliminary findings of a remote sensing analysis of the post–Little Ice Age (LIA) evolution of Svalbard's barrier‐lagoon systems. A total of 430 lagoon systems were investigated to distinguish their genesis and the type of connection to the sea (closed, choked, restricted, or leaky). Since the termination of the LIA, a minimum of 98 lagoons have been formed, whereas eight have disappeared. The majority of lagoons present along the modern coast of Svalbard are of the choked type (almost 48%). Additionally, a new, previously unidentified lagoon type, the moraine‐controlled paraglacial lagoon, has been identified. These systems are formed by retreating marine‐terminating glaciers, which is a dominant process of new coast formation in the rapidly deglaciating Arctic.

Barrier-lagoon systems are among the most sensitive coastal environments, as they accumulate the effects of environmental changes occurring on lands and in the sea. Globally, the stability of lagoons and associated barriers is controlled by the frequency and magnitude of storms approaching the coasts, access to sediment supplies, and resilience to shifts in sea level. However, most studies refer to mid-latitude and tropical coastal zones, with limited insight into cold region lagoon responses. This study presents the first remote sensing analysis of the post-Little-Ice-Age (LIA) evolution of Svalbard's barrier-lagoon systems. A total of 430 lagoon systems were investigated to distinguish their genesis and type of connection to the sea (closed, choked, restricted, or leaky). Since the termination of the LIA, at least 98 lagoons have been formed, while 8 have disappeared. The majority of lagoons present along the modern coast of Svalbard are of the choked type (almost 48%). A new, previously unidentified lagoon type has been identified: the moraine-controlled paraglacial lagoons. These are systems formed by retreating marine-terminating glaciers, which is a dominant process of new coast formation in rapidly deglaciating Arctic.