Southeast Iceland Research Articles

Tracing Ocean Circulation and Mixing From the Arctic to the Subpolar North Atlantic Using the 129I–236U Dual Tracer

AbstractThis study represents the first use of the artificial radionuclides 129I and 236U, released into the ocean mainly from Nuclear Reprocessing Plants, as a dual tracer in the vicinity of Iceland with novel estimation of ocean circulatory pathways and mixing in the region. Iceland lies at the gateway to the Arctic where warm, saline Atlantic waters interact with waters of Arctic origin in ways that have critical consequences for the strength and stability of the Atlantic Meridional Overturning Circulation. Many of these interactions are not yet fully understood, such as how Atlantic water circulates around the Arctic Ocean and Nordic Seas and the composition and fate of the major overflows of the Greenland‐Scotland Ridge. Using new and previous measurements of 129I and 236U in seawater, we present a new method of appraising water mass provenance and mixing in the form of the 129I–236U dual mixing plot. With this method, we estimate that at least half the Atlantic‐origin water entering the Arctic Ocean circulates around the Canada Basin before exiting at Fram Strait and that this outflow is increased by about 40% by mixing with Return Atlantic Water “short‐circuiting” the Arctic Ocean at Fram Strait. We present tracer‐based evidence that water carried by the East Greenland Current has an unbroken pathway to the Faroe‐Shetland Channel and that Iceland‐Scotland Overflow Water (ISOW) entrains 60% Labrador Sea Water during transit past southeast Iceland. We present an unambiguous way to differentiate ISOW from DSOW after they partially merge in the Irminger Sea.

High seed losses in mountain birch (Betula pubescens ssp. tortuosa) and developmental, ecological, and environmental correlates

Abstract Plants typically experience great losses from their reproductive potential represented by ovule production to the post-dispersal crop of viable seed. We examined seed density and viability in a founder population of mountain birch (Betula pubescens ssp. tortuosa), aiming to quantify losses at different stages and examine potential selection forces on the reproduction success of the founder generation of an isolated population. At the time of the study (2017–2020), the population had recently reached reproductive maturity, following its colonization around 1990 through long-distance dispersal onto an early successional outwash plain in southeast Iceland. Seed densities were high, but 89% of apparently intact seeds did not contain an embryo, despite being visually indistinguishable from filled seeds. Externally evident losses amounted to about 45% of the total seed crop and were mostly due to predation by the gall midge Semudobia betulae. When all losses were accounted for, 2.7% of the seed crop remained viable and germinated. Pollen limitation may partially explain the high incidence of empty seeds. Excessive flower production is compatible with the predator satiation hypothesis but cannot explain pre-dispersal losses. Another adaptation to predation, masting, appears poorly developed in Iceland. Our results suggest the presence of constraints on the reproduction potential of the new island population, that are more limiting than in neighbouring populations, and we discuss their developmental, ecological, and environmental correlates.

Post-little ice age glacial geomorphology of contrasting topographic settings at Skálafellsjökull, southeast Iceland

ABSTRACT Glacial geomorphological mapping from the southern margin of Skálafellsjökull, southeast Iceland, depicts a topographically diverse mountainside, influencing glacier dynamics, landform formation and glacier retreat since the Little Ice Age maximum in ∼1890. The glacial landforms present are typical of southeast Icelandic temperate glaciers, comprising recessional push moraines, including sawtooth moraines, and associated fluting. Study area A demonstrates an abandoned lobe confined by steep V-shaped topography, displaying moraines and minimal fluting, suggesting low preservation of landforms, and changes in glacier behaviour. At study area B, the sawtooth moraine morphology demonstrates changes in the glacier margin as the ice interacted with a series of topographic benches during active recession. The steep-sided valley at study area C illustrates densely spaced arcuate moraines, reflecting subtle changes in ice elevation. This mapping provides a framework for further investigations into glacier retreat rates and the influence of local topography and climate.

Volcanic unrest as seen from the magmatic source: Reyðarártindur pluton, Iceland

How the Earth’s crust accommodates magma emplacement influences the signals that can be detected by monitoring volcano seismicity and surface deformation, which are routinely used to forecast volcanic eruptions. However, we lack direct observational links between deformation caused by magma emplacement and monitoring signals. Here we use field mapping and photogrammetry to quantify deformation caused by the emplacement of at least 2.5 km3 of silicic magma in the Reyðarártindur pluton, Southeast Iceland. Our results show that magma emplacement triggered minor and local roof uplift, and that magma reservoir growth was largely aseismic by piecemeal floor subsidence. The occurrence and arrangement of fractures and faults in the reservoir roof can be explained by magmatic overpressure, suggesting that magma influx was not fully accommodated by floor subsidence. The tensile and shear fracturing would have caused detectable seismicity. Overpressure eventually culminated in eruption, as evidenced by exposed conduits that are associated with pronounced local subsidence of the roof rocks, corresponding to the formation of an asymmetric graben at the volcano surface. Hence, the field observations highlight processes that may take place within silicic volcanoes, not accounted for in widely used models to interpret volcanic unrest.

A magnetic fabric study of the origin of englacial debris bands at Fláajökull, Southeast Iceland

Two debris bands associated with an overdeepened basin in the terminus region of the Fláajökull glacier, Iceland, have been sampled for their ice and debris. Here the kinematics of deformation are investigated through anisotropy of magnetic susceptibly (AMS), microstructural analyses, and c-axis preferred orientations. Comparison of the crystallographic orientations of 180 grains and the AMS shape orientations of mineral inclusions in polycrystalline ice reveals a multi-maximum girdle oblique to the planar stratification and a record of near vertical triaxial ellipsoids. These two distinct fabrics can be attributed to both pure and simple shear suggesting a complex deformational history. In addition, AMS from an ice-free sediment ridge on the glacier surface indicates pure shear locally dominated strain. The physical properties of the debris bands, sedimentology and field observations suggest that they were sourced from the glacial bed and emplaced by highly pressurized water into localized fractures.

Genetic variation and origin of mountain birch on a recently colonized glacial outwash plain by Vatnajökull glacier, southeast Iceland

Genetic variation and origin of mountain birch on a recently colonized glacial outwash plain by Vatnajökull glacier, southeast Iceland

The evolution and preservation potential of englacial eskers: An example from Breiðamerkurjökull, SE Iceland

AbstractDirectly observing glacial drainage systems (englacial and subglacial) is challenging. The distribution, morphology and internal structure of eskers can provide valuable information about the glacial drainage system and meltwater processes. This work presents the annual evolution (meltout) and internal structure of an esker emerging from the Breiðamerkurjökull ice margin, southeast Iceland. Changes in esker morphology have been repeatedly mapped over a 1‐year period using high temporal and spatial resolution data acquired by an uncrewed aerial vehicle (UAV). The internal architecture of the esker was investigated using ground‐penetrating radar (GPR) surveys. These data are used to identify the dominant processes driving the formation of this englacial esker and to evaluate the preservation potential. The englacial esker was up to 2.6 m thick and ice‐cored. A large moulin upglacier of the esker, which evolved into an englacial conduit, supplied meltwater to the englacial channel. Upglacier dipping debris‐filled basal hydrofractures, formed by pressurised subglacial meltwater rising up the retrograde bed slope, likely supplied sediment to the englacial conduit. Over the 1‐year period of observation the crest morphology evolved from flat‐ to sharp‐crested and the esker footprint increased by a factor of 5.7 in response to post‐depositional processes. The findings presented here indicate that englacial eskers may have low preservation potential due to post‐depositional reworking such as slumping through ice‐core meltout and erosion by later meltwater flow. As englacial eskers may not be preserved in the landscape, they could represent important glacial drainage system components that are not currently captured in palaeo‐ice sheet reconstructions. This work highlights the value of creating a time series of high‐temporal resolution data to quantify morphological evolution and improve glacial process‐form models.

Geophysical reconstruction of the late Holocene proximal proglacial landsystem at Skeiðarársandur, southeast Iceland

ABSTRACTSandur plains are extensive sedimentary bodies formed in proglacial settings by glaciofluvial processes. Icelandic sandar have been hypothesised to be comprised of thick alluvial successions that provide critical insight into the processes that contributed to their formation and evolution. However, to‐date, most sandar research has focused on the analysis of sedimentary successions associated to topographically‐confined and small‐scale systems. These, however, do not capture the variety or scale of processes that influence sandar architecture. Therefore, detailed subsurface analysis of large‐scale and unconfined sandar is vital to understand how these systems respond to fundamental drivers, such as: (i) glacier oscillations, and (ii) episodic sediment flux from glacier outburst floods (aka. jökulhlaups). We report an extensive, low‐frequency (40 & 100 MHz) ground‐penetrating radar (GPR) survey of the ice‐proximal component of a large‐scale () active sandur in southeast Iceland. A bright and continuous reflection (PR1) is identified within all radargrams and provides a boundary between pre‐LIA and LIA to present‐day sedimentation. GPR data reveals a ~50 m thick ice‐proximal sediment wedge that is attributed to jökulhlaup and surge‐related glaciofluvial activity during the Little Ice Age (LIA). An approximate rate of deposition of 0.2–0.65 m has been calculated for the sediment wedge above PR1. Furthermore, we propose an extensive, sandur‐wide, pre‐LIA ice marginal limit of Skeiðarárökull, southeast Iceland, based on observations reported here and in previous work.

Moss and underlying soil bacterial community structures are linked to moss functional traits

AbstractMosses are among the first colonizing organisms after glacier retreat and can develop into thick moss mats during later successional stages. They are key players in N2 fixation through their microbiome, which is an important process for nutrient buildup during primary succession. How these moss–microbe interactions develop during succession is not well studied and is relevant in the light of climate change and increased glacier retreat. We examined how the bacterial communities associated with two moss species of the genus Racomitrium and the underlying soil, as well as moss traits and nitrogen fixation, develop along a successional gradient in the glacier forefield of Fláajökull in southeast Iceland. In addition, we tested whether moss functional traits, such as total carbon (TC) and total nitrogen (TN) contents, moss moisture content, and moss shoot length are drivers of moss and underlying soil bacterial communities. Although time since deglaciation did not affect TN and moss moisture contents, TC and shoot length increased with time since deglaciation. Moss and underlying soil bacterial communities were distinct. While the soil bacterial community structure was driven by moss C/N ratios, the moss bacterial community structure was linked to time since deglaciation, moss C/N ratio, and moss moisture content. Moss N2‐fixation rates were linked to bacterial community composition and nifH gene abundance rather than moss TN or time since deglaciation. This was accompanied by a shift from autotrophic to heterotrophic diazotrophs. Overall, our results suggest that there is little lateral transfer between moss and soil bacterial communities and that moss traits affect moss and soil bacterial community structure. Only moss bacterial community changed with time since deglaciation. In addition, moss N2‐fixation rates are determined by bacterial community structure, rather than moss traits or time since deglaciation. This study on the interplay between succession, mosses, soils, and their bacterial communities will inform future work on the fate of newly exposed areas as a result of glacier retreat.

Planned relocation due to landslide-triggered tsunami risk in recently deglaciated areas

Climate change is contributing to the magnitude, frequency and location of natural hazards, including landslides and landslide-triggered tsunamis. As the costs of protecting against a given risk increase, relocation may become the only feasible option despite the socio-economic, human security and cultural consequences. The relocation of people represents one of the most complex governance challenges generated by climate change. This article contributes to the literature by presenting insights and lessons from two case studies of unprecedented landslide-triggered tsunami risk in recently deglaciated areas that have not previously been described in the relocation literature: the unstable Svínafellsheiði slopes in south-east Iceland, and Karrat and Uummannaq Fjords in north-west Greenland. Our results draw attention to the need for planned relocation to be conducted in-line with international best practices, including those relating to the active involvement of affected people in decision-making, ensuring adequate compensation, and clarifying relocation planning schedules. This has occurred against a backdrop of colonial power dynamics, urbanisation trends, and the rise of tourism in these locations. Based on the findings, we recommend that the role of government pivot from determining risk management and relocation options, to providing a structure to underpin and support community agency.

Surface-groundwater exchange between a wetland, sandur, and lava field in southeastern Iceland

AbstractIn May 2019, over 50 springs were identified at a sandur-lava field–wetland complex in Southeast Iceland and a subset was selected for further investigation including monitoring water levels, discharge, and water chemistry. Between May and September 2019, springs at the study site had relatively stable water levels and temperatures (4–5 °C), although heavy rains (>10 mm) corresponded with increased water levels and/or temperatures at some springs. Together, the water level, temperature, and stable isotope data suggest that the springs at the study site are fed by older groundwater from an aquifer that is recharged by precipitation. Spikes in water level indicated that at least one spring at the edge of the sandur also received floodwater and shallow subsurface flows from the glacial-fed Brunná River. One wetland spring was further monitored over the water year (October 2019 to October 2020). Like other springs, water levels and temperatures remained relatively stable, fluctuating with inputs of precipitation. Longer-term studies will be needed to gain an improved understanding of seasonal spring vulnerability to climate change and their role in the functioning of a coastal wetland in Southeast Iceland.

Assessing UAV-based laser scanning for monitoring glacial processes and interactions at high spatial and temporal resolutions

Uncrewed Aerial Vehicles (UAVs), in combination with Structure from Motion (SfM) photogrammetry, have become an established tool for reconstructing glacial and ice-marginal topography, yet the method is highly dependent on several factors, all of which can be highly variable in glacial environments. However, recent technological advancements, related primarily to the miniaturisation of new payloads such as compact Laser Scanners (LS), has provided potential new opportunities for cryospheric investigation. Indeed, UAV-LS systems have shown promise in forestry, river, and snow depth research, but to date the method has yet to be deployed in glacial settings. As such, in this study we assessed the suitability of UAV-LS for glacial research by investigating short-term changes in ice surface elevation, calving front geometry and crevasse morphology over the near-terminus region of an actively calving glacier in southeast Iceland. We undertook repeat surveys over a 0.1 km2region of the glacier at sub-daily, daily, and weekly temporal intervals, producing directly georeferenced point clouds at very high spatial resolutions (average of >300 points per m−2at 40 m flying height). Our data has enabled us to: 1) Accurately map surface elevation changes (Median errors under 0.1 m), 2) Reconstruct the geometry and evolution of an active calving front, 3) Produce more accurate estimates of the volume of ice lost through calving, and 4) Better detect surface crevasse morphology, providing future scope to extract size, depth and improve the monitoring of their evolution through time. We also compared our results to data obtained in parallel using UAV-SfM, which further emphasised the relative advantages of our method and suitability in glaciology. Consequently, our study highlights the potential of UAV-LS in glacial research, particularly for investigating glacier mass balance, changing ice dynamics, and calving glacier behaviour, and thus we suggest it has a significant role in advancing our knowledge of, and ability to monitor, rapidly changing glacial environments in future.

Geomorphological map of Breiðamerkursandur 2018: the historical evolution of an active temperate glacier foreland

ABSTRACT We present a geomorphological map of Breiðamerkursandur, the outwash plain and foreland of Breiðamerkurjökull, an outlet glacier of the Vatnajökull ice cap, Southeast Iceland. We trace the glacial retreat of the glacier snout since its historical late nineteenth century Little Ice Age (LIA) maximum extentand the concomitant development of the glacial drainage pathways. Since the outlet began retreating from its LIA terminal position, a 120 km2 area of foreland has been exposed. The mapped geomorphology is a supplementary continuation of previous surveys in the 20th century, which highlighted the geomorphology and ice margin for the years 1945, 1965 and 1998. Since the 1998 landsystem map, Breiðamerkurjökull has retreated a further 0.6–4.0 km and 29 km2 has been exposed. This new map was prepared with the use of remote sensing, LiDAR DEM, a range of oblique aerial photographs and satellite images, written documents, in-field survey measurements and refined landform classifications to more accurately trace the position of the retreating snout and its outlet streams over the last 130 years.

The Environmental History of Skeiðarársandur Outwash Plain, Iceland

We sketch the Holocene history of Skeiðarársandur outwash plain, southeast Iceland, but concentrate on postlandnam changes. The dramatic human history of the Öræfi farming community is well known, but for the first time, medieval cartularia and late 16th to early 20th century sources are combined to reconstruct the plain's environmental history. We identify trends and agents that have allowed recent ecosystem recovery and decribe the zonation and characteristics of the present major ecosystems. Skeiðarársandur's history represents a state shift in an extreme disturbance regime, but it is also set to become a rare example of subsequent recovery through natural processes, albeit indirectly caused by global warming. The plain's eastern flank at least carried extensive birch forests and riparian meadows in the first centuries after settlement. The first documented catastrope was the A.D. 1362 Öræfajökull eruption, and from then on, increasingly desctructive glacial floods swept across Skeiðarársandur, some covering almost the entire 1000 km2 plain. At least 11 farms were abandoned by 1500, and by the 18th century, the farming community west of Öræfajökull had been reduced from ≥20 to four farmsteads. By the late Little Ice Age, Skeiðarársandur was an exceptionally barren wasteland. Over the past 80 years, fewer and less destructive outburst floods, warming climate, and enhanced seed rain with greater species diversity have facilitated plant establishment and rapid vegetation succession in parts of the plain. In the absence of major disturbances, one of the largest natural birch forest in Iceland may develop on Skeiðarársandur.

Paraglacial exposure and collapse of glacial sediment: The 2013 landslide onto Svínafellsjökull, southeast Iceland

AbstractIn the last 130 years, Icelandic glaciers have experienced significant mass loss, and numerous paraglacial slope failures have been documented in the country. One such failure occurred in late February 2013, when a large landslide fell onto the Svínafellsjökull outlet glacier in southeast Iceland. Digital elevation models and aerial imagery were used to quantify the glacial and paraglacial changes leading up to the event, reconstructing the processes that occurred during the landslide and the effects of the debris on the glacier surface. Between 1994 and 2013, glacier thinning and glacier‐retreat exposed a steep lateral moraine perched on bedrock which later failed and caused the landslide. Increased pore‐water pressure after an intense rainstorm and potential fluvial erosion at the toe of the source area are considered to be the primary trigger mechanisms. Morphological evidence indicates multiple phases of movement in the source area and a highly water‐rich debris avalanche on Svínafellsjökull. The debris reached a runout distance of almost 4 km and affected an area of about 1.7 km2. The estimated displaced volume of the slide is 5.33 ± 0.08 × 106 m3, making it the largest documented landslide originating from unconsolidated material in Iceland. The glacier surface ablation beneath the debris deposits was reduced due to insulation, whereas increased glacier thinning was observed surrounding the deposits, resulting in an up to 35 m height difference between the debris‐free and the debris‐covered ice by 2020. This study shows that large catastrophic landslides can originate from, and result in the formation of ice‐cored or frozen sediment complexes and highlights the potential risk coming from similar slopes around the world as glaciers continue to recede and the number of paraglacial landslides increases.

Communicating Risk in Glacier Tourism: A Case Study of the Svínafellsheiði Fracture in Iceland

Every day in early summer 2018, an estimated 1000 tourists went on guided tours of Svínafellsjökull, an outlet glacier in southeast Iceland. However, this changed on 22 June 2018, when a warning was issued against glacial travel due to the risk of a large landslide caused by a fracture in the surrounding mountainside. Tourists often entrust tourism employees with responsibility for their safety; however, there is a dearth of research into the ways in which tourism employees receive and respond to risk communication. These dynamics were explored in this ethnographic study, which drew on 50 semistructured interviews and extensive participant observation. The results indicate that despite demographic shifts, Icelandic inhabitants remain the basic unit on which risk management processes are centered, with repercussions for the ways in which exposure is calculated and risk is communicated. Tourists and tourism employees have a limited understanding of the risk and emergency protocols compared with local inhabitants. We argue that, for their own safety and that of customers, risk communication needs to be tailored to the needs of tourism employees, including guides and hospitality workers. The recommendations that emerge from this research can guide risk communication strategies in other mountainous regions of the world where tourism is an important source of livelihoods.

Psychosocial response to a no-build zone: Managing landslide risk in Iceland

Land use planning has been promoted as a key measure to decrease the risk of natural disasters including landslides, however, there is a dearth of research on how the impact it has on the psychosocial wellbeing of affected people. This ethnographic study examines the risk management of the Svínafellsheiði mountain in south-east Iceland. Scientific monitoring suggests that an estimated 60–100 million cubic metres of bedrock could fall onto the glacier below, and cause flooding or a tsunami in the proglacial lake. A no-build zone was in place between 2018 and 2020 to prevent a further increase in the number of people exposed to the hazard. Our results indicate that the no-build zone had adverse effects on the psychosocial wellbeing of those affected including frustration about a perceived inability to make changes to their home and business operations, leaving them feeling that their future was uncertain or on hold. These frustrations also acted as a persistent reminder of the risk posed by the unstable slope, reinforcing anxiety and undermining people’s ability to gain respite through day-to-day routine. Based on the findings, we recommend that land use planners take the psychosocial wellbeing of affected communities into account when contemplating no-build zones, and that psychosocial support be offered especially when a small group of people face an existential threat for an extended period.

Rapid Assembly and Eruption of a Shallow Silicic Magma Reservoir, Reyðarártindur Pluton, Southeast Iceland

AbstractAlthough it is widely accepted that shallow silicic magma reservoirs exist, and can feed eruptions, their dynamics and longevity are a topic of debate. Here, we use field mapping, geochemistry, 3D pluton reconstruction and a thermal model to investigate the assembly and eruptive history of the shallow Reyðarártindur Pluton, southeast Iceland. Primarily, the exposed pluton is constructed of a single rock unit, the Main Granite (69.9–77.7 wt.% SiO2). Two further units are locally exposed as enclaves at the base of the exposure, the Granite Enclaves (67.4–70.2 wt.% SiO2), and the Quartz Monzonite Enclaves (61.8–67.3 wt.% SiO2). Geochemically, the units are related and were likely derived from the same source reservoir. In 3D, the pluton has a shape characterized by flat roof segments that are vertically offset and a volume of >2.5 km3. The pluton roof is intruded by dikes from the pluton, and in two locations displays depressions associated with large dikes. Within these particular dikes the rock is partially to wholly tuffisitic, and rock compositions range from quartz monzonite to granite. We interpret these zones as eruption‐feeding conduits from the pluton. A lack of cooling contacts throughout the pluton indicates rapid magma emplacement and a thermal model calculates the top 75 m would have rheologically locked up within 1,000 years. Hence, we argue that the Reyðarártindur Pluton was an ephemeral part of the wider plumbing system that feeds a volcano, and that timeframes from emplacement to eruption were rapid.

Channels of the glacial river Jökulsá á Breiðamerkursandi

The glacial river Jökulsá á Breiðamerkursandi drains the Jökulsárlón tidal lagoon (27 km2), in Southeast Iceland. Despite being the shortest glacial outlet (0.6 km), it is among the most voluminous rivers in Iceland, with an estimated average drainage of 250–300 m3/s and has doubled its volume at peak runoff. Until a bridge was established, this was one of Iceland’s most infamous river and for travellers, cruising on horseback, the greatest obstacle to cross on the main road. The river began shaping its present channel in the late 19th century but was not permanently settled until the mid-20th century. Before that it used to wander around the fan, occasionally in several branches, or as a single heavy moving water. In this paper we present a map of its known runoffs and channels that were formed in the 19th and 20th centuries. Few channels were digitized from old maps, but several of those were identified and recorded by the late Flosi Björnsson (1906–1993), a farmer from the Kvísker, who guided travellers across the river before the bridge was built. The Breiðamerkurjökull outlet glacier of Vatnajökull, Southeast Iceland, advanced 10–15 km during the Little Ice Age. During the LIA advance the wide fan shaped shore in front of Breiðamerkurjökull gradually extended outward by >1 km, mainly due to sediment deposition by the Jökulsá river and few other temporal glacial river branches. At the turn of the 20th century the outlet glacier started to retreat slowly and in the 1930s terminal lakes were formed. With the formation of the Jökulsárlón tidal lagoon river dumping at the shore terminated and was replaced by a progressive coastal erosion. Currently ca. 0.9 km has eroded off the coast since the 1930s. A 0.65 km wide strip now remains between the coast and Jökulsárlón tidal lagoon, where the Jökulsá river and the remains of its former runway channels are located.

Local knowledge of emerging hazards: Instability above an Icelandic glacier

Climate change is contributing to shifts in the magnitude and scale of hazards, and the emergence of risks in areas where they were previously unknown. In south-east Iceland, a fracture in the mountainside of Svínafellsheiði threatens to cause between 60 and 100 million cubic metres of rock to fall onto the glacier below. A large landslide could break up the surface of the glacier, crash into the proglacial lake, and affect people and infrastructure downhill. In addition to the unprecedented scale, the Svínafellsheiði fracture represents the first time people and infrastructure have been exposed to this type of hazard in Iceland. In this article we examine the role of local knowledge in disaster risk reduction and management for communities that are facing a particular type of hazard for the first time. We argue that even when a community lacks experience with a specific type of hazard, local knowledge can still play a valuable role in hazard identification and risk management.