Peter T Fretwell

British Antarctic Survey | BAS · MAGIC

The study of cetacean strandings was globally recognised as a priority topic at the 2019 World Marine Mammal Conference, in recognition of its importance for understanding the threats to cetacean communities and, more broadly, the threats to ecosystem and human health. Rising multifaceted anthropogenic and environmental threats across the globe, as...

The biological carbon pump drives a flux of particulate organic carbon (POC) through the ocean and affects atmospheric levels of carbon dioxide. Short term, episodic flux events are hard to capture with current observational techniques and may thus be underrepresented in POC flux estimates. We model the potential hidden flux of POC originating from...

The recent rapid growth of rifts in the Brunt Ice Shelf appears to signal the onset of its largest calving event since records began in 1915. The aim of this study is to determine whether this calving event will lead to a new steady state where the Brunt Ice Shelf remains in contact with the bed, or an unpinning from the bed, which could pre-dispos...

The East Antarctic Ice Sheet discharges into the Weddell Sea via the Coats Land ice margin. We have used geophysical data to determine the changing ice-sheet configuration in this region through its last glacial advance and Holocene retreat and to identify constraints on its future stability. Methods included high-resolution multibeam bathymetry, s...

The East Antarctic Ice Sheet discharges into the Weddell Sea via the Coats Land ice margin. We have used geophysical data to determine the changing ice sheet configuration in this region through its last advance and retreat, and identify constraints on its future stability. Methods included high-resolution multibeam-bathymetry, sub-bottom profiles,...

This study is the first to utilize 30-cm resolution imagery from the WorldView-3 (WV-3) satellite to count wildlife directly. We test the accuracy of the satellite method for directly counting individuals at a well-studied colony of Wandering Albatross Diomedea exulans at South Georgia, and then apply it to the closely related Northern Royal Albatr...

Changes in penguin populations on the Antarctic Peninsula have been linked to several environmental factors, but the potentially devastating impact of volcanic activity has not been considered. Here we use detailed biogeochemical analyses to track past penguin colony change over the last 8,500 years on Ardley Island, home to one of the Antarctic Pe...

Key datasets for Figure 3

Key datasets for Figure 5

Yanou Lake sediment record geochemical data

Modern-day Ardley Island penguin count data and statistical analysis

Supplementary Notes, Supplementary Discussion, Supplementary Methods, Supplementary Figures, Supplementary Tables and Supplementary References

Key datasets for Figures 4 and 5

New glass shard Electron Microprobe Analysis (EMPA) data for tephra deposits for this study and published comparison data

Ardley Lake sediment record geochemical data

Antarctic krill (Euphausia superba) and salps are major macroplankton contributors to Southern Ocean food webs and krill are also fished commercially. Managing this fishery sustainably, against a backdrop of rapid regional climate change, requires information on distribution and time trends. Many data on the abundance of both taxa have been obtaine...

Detecting and predicting how populations respond to environmental variability are crucial challenges for their conservation. Knowledge about the abundance and distribution of the emperor penguin is far from complete despite recent information from satellites. When exploring the locations where emperor penguins breed, it is apparent that their distr...

Antarctic krill (Euphausia superba) and salps are major macroplankton contributors to Southern Ocean food webs and krill are also fished commercially. Managing this fishery sustainably, against a backdrop of rapid regional climate change, requires information on distribution and time trends. Many data on the abundance of both taxa have been obtaine...

As the accuracy and sensitivity of remote-sensing satellites improve, there is an increasing demand for more accurate and updated base datasets for surveying and monitoring. However, differentiating rock outcrop from snow and ice is a particular problem in Antarctica, where extensive cloud cover and widespread shaded regions lead to classification...

The thermal infrared portion of the electromagnetic spectrum has considerable potential for mineral and lithological mapping of the most abundant rock-forming silicates that do not display diagnostic features at visible and shortwave infrared wavelengths. Lithological mapping using visible and shortwave infrared hyperspectral data is well developed...

Climate change can have major effects on the distribution of species. In marine ecosystems, the cold waters of the Arctic have restricted warmer water species from crossing between Eurasia and North America. However, with Arctic waters becoming warmer, various marine species have expanded their distribution. Cuttlefish are fast-growing, voracious p...

The South Sandwich Islands and associated seamounts constitute the volcanic arc of an active subduction system situated in the South Atlantic. We introduce a map of the bathymetry and geological setting of the South Sandwich Islands and the associated East Scotia Ridge back-arc spreading centre that consists of two sides: side 1, a regional overvie...

Differentiating exposed rock from snow and ice is a particular problem in Antarctica where extensive cloud cover and widespread shaded regions lead to classification errors. The existing rock outcrop dataset has significant georeferencing issues including overestimation and generalisation of rock exposure areas. The most commonly used method for au...

On the Antarctic Peninsula, lichens are the most diverse botanical component of the terrestrial ecosystem. However, detailed information on the distribution of lichens on the Antarctic Peninsula region is scarce, and the data available exhibit significant heterogeneity in sampling frequency and effort. Satellite remote sensing, in particular the us...

Soil fungi have pivotal ecological roles as decomposers, pathogens and symbionts. Alterations to their diversity arising from climate change could have substantial effects on ecosystems, particularly those undergoing rapid warming that contain few species. Here, we report a study using pyrosequencing to assess fungal diversity in 29 soils sampled f...

Antarctica is a unique and geographically remote environment. Field campaigns in the region encounter numerous challenges including the harsh polar climate, steep topography, and high infrastructure costs. Additionally, field campaigns are often limited in terms of spatial and temporal resolution, and particularly, the topographical challenges pres...

Ice shelves in West Antarctica have been shown to melt where warm circumpolar deep water enters a sub-shelf cavity. A bathymetric reconstruction of Totten Glacier in East Antarctica suggests that the same process may be at work there.

Changes in penguin abundance and distribution can be used to understand the response of species to climate change and fisheries pressures, and as a gauge of ecosystem health. Traditionally, population estimates have involved direct counts, but remote sensing and digital mapping methodologies can provide us with alternative techniques for assessing...

The spectral signature of seabird guano is unique.•Landsat imagery can be used to isolate the signature from geology and vegetation.•The guano signature was used to map Antarctic Peninsula seabird colonies.•All major colonies from several species of seabird in the test area were identified.•The method could be transferable to other remote regions o...

The Antarctic Peninsula (AP) is one of the most rapidly changing environments on the planet; mean annual air temperatures have increased by ~3 ºC in the last 50 years. This climatic change has led to longer summers and higher summer-growing season temperatures and, coupled with local glacial retreat, new bare-ground is exposed for colonisation by p...

Site fidelity is an important evolutionary trait to understand, as misinterpretation of philopatric behavior could lead to confusion over the key drivers of population dynamics and the environmental or anthropogenic factors influencing populations. Our objective was to explore the hypothesis that emperor penguins are strictly philopatric using sate...

Evaluating the demographic trends of marine top predators is critical to understanding the processes involved in the ongoing rapid changes in Antarctic ecosystems. However, the remoteness and logistical complexity of operating in Antarctica, especially during winter, make such an assessment difficult. Satellite imaging is increasingly recognised as...

The first airborne hyperspectral campaign in the Antarctic Peninsula region was carried out by the British Antarctic Survey and partners in February 2011. This paper presents an insight into the applicability of currently available radiative transfer modelling and atmospheric correction techniques for processing airborne hyperspectral data in this...

We describe a method of identifying and counting whales using very high resolution satellite imagery through the example of southern right whales breeding in part of the Golfo Nuevo, Península Valdés in Argentina. Southern right whales have been extensively hunted over the last 300 years and although numbers have recovered from near extinction in t...

We describe a new breeding behaviour discovered in emperor penguins; utilizing satellite and aerial-survey observations four emperor penguin breeding colonies have been recorded as existing on ice-shelves. Emperors have previously been considered as a sea-ice obligate species, with 44 of the 46 colonies located on sea-ice (the other two small colon...

As part of a collaborative project between BAS, DRDC Suffield (Canada) and ITRES Research Ltd., (Canada) the first known airborne hyperspectral dataset was acquired over the Antarctic in February 2011. The simultaneous deployment of commercially available visible-near infrared and shortwave infrared spectrometers generated a dataset covering 0.35 t...

The Gamburtsev Subglacial Mountains are regarded as a key nucleation site for the Antarctic Ice Sheet and they retain a unique long-term record of pre-glacial and early glacial landscape evolution. Here, we use a range of morphometric analyses to constrain the nature of early glaciation and subsequent ice sheet evolution in the interior of East Ant...

Bedmap2; Mapping, visualizing and communicating the Antarctic sub-glacial environment. The Bedmap2 project has been a large cooperative effort to compile, model, map and visualize the ice-rock interface beneath the Antarctic ice sheet. Here we present the final output of that project; the Bedmap2 printed map. The map is an A1, double sided print, s...

We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In particu...

We present Bedmap2, a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 • S. We derived these products using data from a variety of sources, including many substantial surveys completed since the original Bedmap compilation (Bedmap1) in 2001. In parti...

The ocean ecosystems around the west Antarctic Peninsula and South Georgia are two of the best described regional ecosystems of the Southern Ocean. They therefore provide a useful basis for developing comparative analyses of ocean ecosystems around the Antarctic. There are clear and expected differences in seasonality and species composition betwee...

The ocean ecosystems around the west Antarctic Peninsula and South Georgia are two of the best described regional ecosystems of the Southern Ocean. They therefore provide a useful basis for developing comparative analyses of ocean ecosystems around the Antarctic. There are clear and expected differences in seasonality and species composition betwee...

Systematic conservation planning for developing marine spatial protection includes analysis of the spatial distribution of fishing activities, existing management and ecological characteristics. This paper assesses the overlap between habitat (bioregion), existing spatial management and Antarctic krill catch in the Southern Ocean. The analysis requ...

a b s t r a c t Temporal and spatial patterns of relative sea level (RSL) change in the North of Britain and Ireland during the Holocene are examined. Four episodes, each defined by marked changes in the RSL trend, are identified. Each episode is marked by a rise to a culminating shoreline followed by a fall. Episode HRSL-1 dates from the Younger D...

We studied the glacial geomorphology and geochronology of two ice-free valleys in the Dufek Massif (Antarctic Specially Protected Area 119) providing new constraints on past ice sheet thickness in the Weddell Sea embayment. 10Be and 26Al cosmogenic surface exposure dating provided chronological control. Seven glacial stages are proposed. These incl...

Studying emperor penguins used to be a job for heroes. But penguins leave traces; thanks to high‐resolution satellites they can waddle but they cannot hide. Peter Fretwell comes in from the cold to find that penguin numbers are much higher than we thought.

[This corrects the article on p. e33751 in vol. 7.].

Our aim was to estimate the population of emperor penguins (Aptenodytes fosteri) using a single synoptic survey. We examined the whole continental coastline of Antarctica using a combination of medium resolution and Very High Resolution (VHR) satellite imagery to identify emperor penguin colony locations. Where colonies were identified, VHR imagery...

Emperor penguin colonies 2009. Size of circle relates to estimated number of pairs in each colony. (EPS)

Several recent empirical studies have challenged the prevailing dogma that broadcast-spawning species exhibit little or no population genetic structure by documenting genetic discontinuities associated with large-scale oceanographic features. However, relatively few studies have explored patterns of genetic differentiation over fine spatial scales....

Abstract: Globally, areas categorically known to be free of human visitation are rare, but still exist in Antarctica. Such areas may be among the most pristine locations remaining on Earth and, therefore, be valuable as baselines for future comparisons with localities impacted by human activities, and as sites preserved for scientific research usin...

We present BEDMAP2, a new, updated and continuous map of bed elevation and ice thickness for Antarctica and the southern ocean from a large international consortium of Antarctic field programs. We have incorporated all of the ice thickness data from the original BEDMAP with approximately 265 000 km of newly acquired airborne radio-echo-sounding lin...

Coupled ice-sheet and climate models predict that the Gamburtsev Subglacial Mountains (hereafter, Gamburtsevs) were a key nucleation site for the East Antarctic Ice Sheet (EAIS), 34 million years ago. However, evidence for the scale and shape of the EAIS since its inception is limited and generally restricted towards present-day ice sheet margins....

a b s t r a c t Precise relative sea level (RSL) data are important for inferring regional ice sheet histories, as well as helping to validate numerical models of ice sheet evolution and glacial isostatic adjustment. Here we develop a new RSL curve for Fildes Peninsula, South Shetland Islands (SSIs), a sub-Antarctic archipelago peripheral to the no...

1] The West Antarctic ice sheet (WAIS) has long been considered vulnerable to rapid retreat and today parts are rapidly losing ice. Projection of future change in WAIS is, however, hampered by our poor under-standing of past changes, especially during interglacial periods that could be analogs for the future, but which undoubtedly provide an opport...

The multilateral failure to apply the Convention on Biological Diversity (CBD) by the target year 2010 was headline news as are the accelerating climatic changes which dictate its urgency. Some ecosystems that are vulnerable to anthropogenic change have few species listed as endangered because too little is known about their biota. The highest vuln...

In 1948, a small colony of emperor penguins Aptenodytes forsteri was discovered breeding on Emperor Island (67° 51' 52″ S, 68° 42' 20″ W), in the Dion Islands, close to the West Antarctic Peninsula (Stonehouse 1952). When discovered, the colony comprised approximately 150 breeding pairs; these numbers were maintained until 1970, after which time th...

We present the first regional map of vegetation of anywhere on the Antarctic continent based on remote sensing (RS) data. We have used a normalized difference vegetation index (NDVI) for the examination of Landsat ETM data on the Antarctic Peninsula. The results show that 44.6km2 (0.086%) of the study area (74,468km2) is classed with a probability...

Globally, areas categorically known to be free of human visitation are rare, but still exist in Antarctica. Such areas may be among the most pristine locations remaining on Earth and, therefore, be valuable as baselines for future comparisons with localities impacted by human activities, and as sites preserved for scientific research using increasi...

Precise relative sea level (RSL) data are important for inferring regional ice sheet histories, as well as helping to validate numerical models of ice sheet evolution and glacial isostatic adjustment. Here we develop a new RSL curve for Fildes Peninsula, South Shetland Islands (SSIs), a sub-Antarctic archipelago peripheral to the northern Antarctic...

This chapter provides a background to research on Northern krill biology, starting with a description of its morphology and identifying features, and the historical path to its eventual position as a single-species genus. There is a lack of any euphausiid fossil material, so phylogenetic analysis has relied on comparative morphology and ontogeny an...

We present new isobases constraining the Holocene isostatic uplift of the South Shetland Islands, northern Antarctic Peninsula, based on evidence from raised shorelines. Holocene shorelines were described and surveyed at fifteen sites to determine the spatial variability of relative sea level (RSL) change across the South Shetland Islands, and prov...