Fraser William R.

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Fraser

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William R.

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West Antarctic Peninsula : an ice-dependent coastal marine ecosystem in transition

(The Oceanography Society, 2013-09) Ducklow, Hugh W. ; Fraser, William R. ; Meredith, Michael P. ; Stammerjohn, Sharon E. ; Doney, Scott C. ; Martinson, Douglas G. ; Sailley, Sevrine F. ; Schofield, Oscar M. E. ; Steinberg, Deborah K. ; Venables, Hugh J. ; Amsler, Charles D.

The extent, duration, and seasonality of sea ice and glacial discharge strongly influence Antarctic marine ecosystems. Most organisms' life cycles in this region are attuned to ice seasonality. The annual retreat and melting of sea ice in the austral spring stratifies the upper ocean, triggering large phytoplankton blooms. The magnitude of the blooms is proportional to the winter extent of ice cover, which can act as a barrier to wind mixing. Antarctic krill, one of the most abundant metazoan populations on Earth, consume phytoplankton blooms dominated by large diatoms. Krill, in turn, support a large biomass of predators, including penguins, seals, and whales. Human activity has altered even these remote ecosystems. The western Antarctic Peninsula region has warmed by 7°C over the past 50 years, and sea ice duration has declined by almost 100 days since 1978, causing a decrease in phytoplankton productivity in the northern peninsula region. Besides climate change, Antarctic marine systems have been greatly altered by harvesting of the great whales and now krill. It is unclear to what extent the ecosystems we observe today differ from the pristine state.
Antarctic penguin response to habitat change as Earth's troposphere reaches 2°C above preindustrial levels

(Ecological Society of America, 2010-02) Ainley, David G. ; Russell, Joellen ; Jenouvrier, Stephanie ; Woehler, Eric ; Lyver, Philip O'B. ; Fraser, William R. ; Kooyman, Gerald L.

We assess the response of pack ice penguins, Emperor (Aptenodytes forsteri) and Adélie (Pygoscelis adeliae), to habitat variability and, then, by modeling habitat alterations, the qualitative changes to their populations, size and distribution, as Earth's average tropospheric temperature reaches 2°C above preindustrial levels (ca. 1860), the benchmark set by the European Union in efforts to reduce greenhouse gases. First, we assessed models used in the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) on penguin performance duplicating existing conditions in the Southern Ocean. We chose four models appropriate for gauging changes to penguin habitat: GFDL-CM2.1, GFDL-CM2.0, MIROC3.2(hi-res), and MRI-CGCM2.3.2a. Second, we analyzed the composited model ENSEMBLE to estimate the point of 2°C warming (2025–2052) and the projected changes to sea ice coverage (extent, persistence, and concentration), sea ice thickness, wind speeds, precipitation, and air temperatures. Third, we considered studies of ancient colonies and sediment cores and some recent modeling, which indicate the (space/time) large/centennial-scale penguin response to habitat limits of all ice or no ice. Then we considered results of statistical modeling at the temporal interannual-decadal scale in regard to penguin response over a continuum of rather complex, meso- to large-scale habitat conditions, some of which have opposing and others interacting effects. The ENSEMBLE meso/decadal-scale output projects a marked narrowing of penguins' zoogeographic range at the 2°C point. Colonies north of 70° S are projected to decrease or disappear: 50% of Emperor colonies (40% of breeding population) and 75% of Adélie colonies (70% of breeding population), but limited growth might occur south of 73° S. Net change would result largely from positive responses to increase in polynya persistence at high latitudes, overcome by decreases in pack ice cover at lower latitudes and, particularly for Emperors, ice thickness. Adélie Penguins might colonize new breeding habitat where concentrated pack ice diverges and/or disintegrating ice shelves expose coastline. Limiting increase will be decreased persistence of pack ice north of the Antarctic Circle, as this species requires daylight in its wintering areas. Adélies would be affected negatively by increasing snowfall, predicted to increase in certain areas owing to intrusions of warm, moist marine air due to changes in the Polar Jet Stream.
Penguin biogeography along the West Antarctic Peninsula : testing the canyon hypothesis with Palmer LTER observations

(The Oceanography Society, 2013-09) Schofield, Oscar M. E. ; Ducklow, Hugh W. ; Bernard, Kim S. ; Doney, Scott C. ; Patterson-Fraser, Donna ; Gorman, Kristen ; Martinson, Douglas G. ; Meredith, Michael P. ; Saba, Grace ; Stammerjohn, Sharon E. ; Steinberg, Deborah K. ; Fraser, William R.

The West Antarctic Peninsula (WAP) is home to large breeding colonies of the ice-dependent Antarctic Adélie penguin (Pygoscelis adeliae). Although the entire inner continental shelf is highly productive, with abundant phytoplankton and krill populations, penguin colonies are distributed heterogeneously along the WAP. This ecological conundrum targets a long-standing question of interest: what environmental factors structure the locations of Adélie penguin "hot spots" throughout the WAP?
BioTIME : a database of biodiversity time series for the Anthropocene

(John Wiley & Sons, 2018-07-24) Dornelas, Maria ; Antao, Laura H. ; Moyes, Faye ; Bates, Amanda E. ; Magurran, Anne E. ; Adam, Dusan ; Akhmetzhanova, Asem A. ; Appeltans, Ward ; Arcos, Jose Manuel ; Arnold, Haley ; Ayyappan, Narayanan ; Badihi, Gal ; Baird, Andrew H. ; Barbosa, Miguel ; Barreto, Tiago Egydio ; Bässler, Claus ; Bellgrove, Alecia ; Belmaker, Jonathan ; Benedetti-Cecchi, Lisandro ; Bett, Brian J. ; Bjorkman, Anne D. ; Błazewicz, Magdalena ; Blowes, Shane A. ; Bloch, Christopher P. ; Bonebrake, Timothy C. ; Boyd, Susan ; Bradford, Matt ; Brooks, Andrew J. ; Brown, James H. ; Bruelheide, Helge ; Budy, Phaedra ; Carvalho, Fernando ; Castaneda-Moya, Edward ; Chen, Chaolun Allen ; Chamblee, John F. ; Chase, Tory J. ; Collier, Laura Siegwart ; Collinge, Sharon K. ; Condit, Richard ; Cooper, Elisabeth J. ; Cornelissen, Johannes H. C. ; Cotano, Unai ; Crow, Shannan Kyle ; Damasceno, Gabriella ; Davies, Claire H. ; Davis, Robert A. ; Day, Frank P. ; Degraer, Steven ; Doherty, Tim S. ; Dunn, Timothy E. ; Durigan, Giselda ; Duffy, J. Emmett ; Edelist, Dor ; Edgar, Graham J. ; Elahi, Robin ; Elmendorf, Sarah C. ; Enemar, Anders ; Ernest, S. K. Morgan ; Escribano, Ruben ; Estiarte, Marc ; Evans, Brian S. ; Fan, Tung-Yung ; Farah, Fabiano Turini ; Fernandes, Luiz Loureiro ; Farneda, Fabio Z. ; Fidelis, Alessandra ; Fitt, Robert ; Fosaa, Anna Maria ; Franco, Geraldo Antonio Daher Correa ; Frank, Grace E. ; Fraser, William R. ; García, Hernando ; Gatti, Roberto Cazzolla ; Givan, Or ; Gorgone-Barbosa, Elizabeth ; Gould, William A. ; Gries, Corinna ; Grossman, Gary D. ; Gutierrez, Julio R. ; Hale, Stephen ; Harmon, Mark E. ; Harte, John ; Haskins, Gary ; Henshaw, Donald L. ; Hermanutz, Luise ; Hidalgo, Pamela ; Higuchi, Pedro ; Hoey, Andrew S. ; Hoey, Gert Van ; Hofgaard, Annika ; Holeck, Kristen ; Hollister, Robert D. ; Holmes, Richard ; Hoogenboom, Mia ; Hsieh, Chih-hao ; Hubbell, Stephen P. ; Huettmann, Falk ; Huffard, Christine L. ; Hurlbert, Allen H. ; Ivanauskas, Natalia Macedo ; Janík, David ; Jandt, Ute ; Jazdzewska, Anna ; Johannessen, Tore ; Johnstone, Jill F. ; Jones, Julia ; Jones, Faith A. M. ; Kang, Jungwon ; Kartawijaya, Tasrif ; Keeley, Erin C. ; Kelt, Douglas A. ; Kinnear, Rebecca ; Klanderud, Kari ; Knutsen, Halvor ; Koenig, Christopher C. ; Kortz, Alessandra R. ; Kral, Kamil ; Kuhnz, Linda A. ; Kuo, Chao-Yang ; Kushner, David J. ; Laguionie-Marchais, Claire ; Lancaster, Lesley T. ; Lee, Cheol Min ; Lefcheck, Jonathan S. ; Levesque, Esther ; Lightfoot, David ; Lloret, Francisco ; Lloyd, John D. ; Lopez-Baucells, Adria ; Louzao, Maite ; Madin, Joshua S. ; Magnusson, Borgbor ; Malamud, Shahar ; Matthews, Iain ; McFarland, Kent P. ; McGill, Brian ; McKnight, Diane ; McLarney, William O. ; Meador, Jason ; Meserve, Peter L. ; Metcalfe, Daniel J. ; Meyer, Christoph F. J. ; Michelsen, Anders ; Milchakova, Nataliya ; Moens, Tom ; Moland, Even ; Moore, Jon ; Moreira, Carolina Mathias ; Muller, Jorg ; Murphy, Grace ; Myers-Smith, Isla H. ; Myster, Randall W. ; Naumov, Andrew ; Neat, Francis ; Nelson, James A. ; Nelson, Michael Paul ; Newton, Stephen F. ; Norden, Natalia ; Oliver, Jeffrey C. ; Olsen, Esben M. ; Onipchenko, Vladimir G. ; Pabis, Krzysztof ; Pabst, Robert J. ; Paquette, Alain ; Pardede, Sinta ; Paterson, David M. ; Pelissier, Raphael ; Penuelas, Josep ; Perez-Matus, Alejandro ; Pizarro, Oscar ; Pomati, Francesco ; Post, Eric ; Prins, Herbert H. T. ; Priscu, John C. ; Provoost, Pieter ; Prudic, Kathleen L. ; Pulliainen, Erkki ; Ramesh, B. B. ; Ramos, Olivia Mendivil ; Rassweiler, Andrew ; Rebelo, Jose Eduardo ; Reed, Daniel C. ; Reich, Peter B. ; Remillard, Suzanne M. ; Richardson, Anthony J. ; Richardson, J. Paul ; Rijn, Itai van ; Rocha, Ricardo ; Rivera-Monroy, Victor H. ; Rixen, Christian ; Robinson, Kevin P. ; Rodrigues, Ricardo Ribeiro ; Rossa-Feres, Denise de Cerqueira ; Rudstam, Lars ; Ruhl, Henry A. ; Ruz, Catalina S. ; Sampaio, Erica M. ; Rybicki, Nancy ; Rypel, Andrew ; Sal, Sofia ; Salgado, Beatriz ; Santos, Flavio A. M. ; Savassi-Coutinho, Ana Paula ; Scanga, Sara ; Schmidt, Jochen ; Schooley, Robert ; Setiawan, Fakhrizal ; Shao, Kwang-Tsao ; Shaver, Gaius R. ; Sherman, Sally ; Sherry, Thomas W. ; Sicinski, Jacek ; Sievers, Caya ; da Silva, Ana Carolina ; da Silva, Fernando Rodrigues ; Silveira, Fabio L. ; Slingsby, Jasper ; Smart, Tracey ; Snell, Sara J. ; Soudzilovskaia, Nadejda A. ; Souza, Gabriel B. G. ; Souza, Flaviana Maluf ; Souza, Vinícius Castro ; Stallings, Christopher D. ; Stanforth, Rowan ; Stanley, Emily H. ; Sterza, Jose Mauro ; Stevens, Maarten ; Stuart-Smith, Rick ; Suarez, Yzel Rondon ; Supp, Sarah ; Tamashiro, Jorge Yoshio ; Tarigan, Sukmaraharja ; Thiede, Gary P. ; Thorn, Simon ; Tolvanen, Anne ; Toniato, Maria Teresa Zugliani ; Totland, Orjan ; Twilley, Robert R. ; Vaitkus, Gediminas ; Valdivia, Nelson ; Vallejo, Martha Isabel ; Valone, Thomas J. ; Van Colen, Carl ; Vanaverbeke, Jan ; Venturoli, Fabio ; Verheye, Hans M. ; Vianna, Marcelo ; Vieira, Rui P. ; Vrska, Tomas ; Vu, Con Quang ; Vu, Lien Van ; Waide, Robert B. ; Waldock, Conor ; Watts, David ; Webb, Sara ; Wesołowski, Tomasz ; White, Ethan P. ; Widdicombe, Claire E. ; Wilgers, Wilgers ; Williams, Richard ; Williams, Stefan B. ; Williamson, Mark ; Willig, Michael R. ; Willis, Trevor J. ; Wipf, Sonja ; Woods, Kerry D. ; Woehler, Eric ; Zawada, Kyle ; Zettler, Michael L.

The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community‐led open‐source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene. The database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record. BioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2). BioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year. BioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.
Carbon fluxes and pelagic ecosystem dynamics near two western Antarctic Peninsula Adélie penguin colonies : an inverse model approach

(Inter-Research, 2013-10-31) Sailley, Sevrine F. ; Ducklow, Hugh W. ; Moeller, Holly V. ; Fraser, William R. ; Schofield, Oscar M. E. ; Steinberg, Deborah K. ; Garzio, Lori M. ; Doney, Scott C.

An inverse food-web model for the western Antarctic Peninsula (WAP) pelagic food web was constrained with data from Palmer Long Term Ecological Research (PAL-LTER) project annual austral summer sampling cruises. Model solutions were generated for 2 regions with Adélie penguin Pygoscelis adeliae colonies presenting different population trends (a northern and a southern colony) for a 12 yr period (1995-2006). Counter to the standard paradigm, comparisons of carbon flow through bacteria, microzooplankton, and krill showed that the diatom-krill-top predator food chain is not the dominant pathway for organic carbon exchanges. The food web is more complex, including significant contributions by microzooplankton and the microbial loop. Using both inverse model results and network indices, it appears that in the northern WAP the food web is dominated by the microbial food web, with a temporal trend toward its increasing importance. The dominant pathway for the southern WAP food web varies from year to year, with no detectable temporal trend toward dominance of microzooplankton versus krill. In addition, sensitivity analyses indicated that the northern colony of Adélie penguins, whose population size has been declining over the past 35 yr, appears to have sufficient krill during summer to sustain its basic metabolic needs and rear chicks, suggesting the importance of other processes in regulating the Adélie population decline.
Effect of continental shelf canyons on phytoplankton biomass and community composition along the western Antarctic Peninsula

(Inter-Research, 2015-03-30) Kavanaugh, Maria T. ; Abdala, F. N. ; Ducklow, Hugh W. ; Glover, David M. ; Fraser, William R. ; Martinson, Douglas G. ; Stammerjohn, Sharon E. ; Schofield, Oscar M. E. ; Doney, Scott C.

The western Antarctic Peninsula is experiencing dramatic climate change as warm, wet conditions expand poleward and interact with local physics and topography, causing differential regional effects on the marine ecosystem. At local scales, deep troughs (or canyons) bisect the continental shelf and act as conduits for warm Upper Circumpolar Deep Water, with reduced seasonal sea ice coverage, and provide a reservoir of macro- and micronutrients. Shoreward of many canyon heads are Adélie penguin breeding colonies; it is hypothesized that these locations reflect improved or more predictable access to higher biological productivity overlying the canyons. To synoptically assess the potential impacts of regional bathymetry on the marine ecosystem, 4 major canyons were identified along a latitudinal gradient west of the Antarctic Peninsula using a high-resolution bathymetric database. Biological-physical dynamics above and adjacent to canyons were compared using in situ pigments and satellite-derived sea surface temperature, sea ice and ocean color variables, including chlorophyll a (chl a) and fucoxanthin derived semi-empirically from remote sensing reflectance. Canyons exhibited higher sea surface temperature and reduced sea ice coverage relative to adjacent shelf areas. In situ and satellite-derived pigment patterns indicated increased total phytoplankton and diatom biomass over the canyons (by up to 22 and 35%, respectively), as well as increases in diatom relative abundance (fucoxanthin:chl a). While regional heterogeneity is apparent, canyons appear to support a phytoplankton community that is conducive to both grazing by krill and enhanced vertical export, although it cannot compensate for decreased biomass and diatom relative abundance during low sea ice conditions.
Circumpolar analysis of the Adélie Penguin reveals the importance of environmental variability in phenological mismatch

(John Wiley & Sons, 2017-03-20) Youngflesh, Casey ; Jenouvrier, Stephanie ; Li, Yun ; Ji, Rubio ; Ainley, David G. ; Ballard, Grant ; Barbraud, Christophe ; Delord, Karine ; Dugger, Katie M. ; Emmerson, Louise M. ; Fraser, William R. ; Hinke, Jefferson T. ; Lyver, Philip O'B. ; Olmastroni, Silvia ; Southwell, Colin J. ; Trivelpiece, Susan G. ; Trivelpiece, Wayne Z. ; Lynch, Heather J.

Evidence of climate-change-driven shifts in plant and animal phenology have raised concerns that certain trophic interactions may be increasingly mismatched in time, resulting in declines in reproductive success. Given the constraints imposed by extreme seasonality at high latitudes and the rapid shifts in phenology seen in the Arctic, we would also expect Antarctic species to be highly vulnerable to climate-change-driven phenological mismatches with their environment. However, few studies have assessed the impacts of phenological change in Antarctica. Using the largest database of phytoplankton phenology, sea-ice phenology, and Adélie Penguin breeding phenology and breeding success assembled to date, we find that, while a temporal match between Penguin breeding phenology and optimal environmental conditions sets an upper limit on breeding success, only a weak relationship to the mean exists. Despite previous work suggesting that divergent trends in Adélie Penguin breeding phenology are apparent across the Antarctic continent, we find no such trends. Furthermore, we find no trend in the magnitude of phenological mismatch, suggesting that mismatch is driven by interannual variability in environmental conditions rather than climate-change-driven trends, as observed in other systems. We propose several criteria necessary for a species to experience a strong climate-change-driven phenological mismatch, of which several may be violated by this system.
Long‐term patterns in ecosystem phenology near Palmer Station, Antarctica, from the perspective of the Adélie penguin

(Ecological Society of America, 2023-02-10) Cimino, Megan A. ; Conroy, John A. ; Connors, Elizabeth ; Bowman, Jeff ; Corso, Andrew ; Ducklow, Hugh ; Fraser, William ; Friedlaender, Ari ; Kim, Heather Hyewon ; Larsen, Gregory D. ; Moffat, Carlos ; Nichols, Ross ; Pallin, Logan ; Patterson‐Fraser, Donna ; Roberts, Darren ; Roberts, Megan ; Steinberg, Deborah K. ; Thibodeau, Patricia ; Trinh, Rebecca ; Schofield, Oscar ; Stammerjohn, Sharon

Climate change is leading to phenological shifts across a wide range of species globally. Polar oceans are hotspots of rapid climate change where sea ice dynamics structure ecosystems and organismal life cycles are attuned to ice seasonality. To anticipate climate change impacts on populations and ecosystem services, it is critical to understand ecosystem phenology to determine species activity patterns, optimal environmental windows for processes like reproduction, and the ramifications of ecological mismatches. Since 1991, the Palmer Antarctica Long‐Term Ecological Research (LTER) program has monitored seasonal dynamics near Palmer Station. Here, we review the species that occupy this region as year‐round residents, seasonal breeders, or periodic visitors. We show that sea ice retreat and increasing photoperiod in the spring trigger a sequence of events from mid‐November to mid‐February, including Adélie penguin clutch initiation, snow melt, calm conditions (low winds and warm air/sea temperature), phytoplankton blooms, shallow mixed layer depths, particulate organic carbon flux, peak humpback whale abundances, nutrient drawdown, and bacterial accumulation. Subsequently, from May to June, snow accumulates, zooplankton indicator species appear, and sea ice advances. The standard deviation in the timing of most events ranged from ~20 to 45 days, which was striking compared with Adélie penguin clutch initiation that varied <1 week. In general, during late sea ice retreat years, events happened later (~5 to >30 days) than mean dates and the variability in timing was low (<20%) compared with early ice retreat years. Statistical models showed the timing of some events were informative predictors (but not sole drivers) of other events. From an Adélie penguin perspective, earlier sea ice retreat and shifts in the timing of suitable conditions or prey characteristics could lead to mismatches, or asynchronies, that ultimately influence chick survival via their mass at fledging. However, more work is needed to understand how phenological shifts affect chick thermoregulatory costs and the abundance, availability, and energy content of key prey species, which support chick growth and survival. While we did not detect many long‐term phenological trends, we expect that when sea ice trends become significant within our LTER time series, phenological trends and negative effects from ecological mismatches will follow.
Top predators in relation to bathymetry, ice and krill during austral winter in Marguerite Bay, Antarctica

( 2007-03-15) Ribic, Christine A. ; Chapman, Erik ; Fraser, William R. ; Lawson, Gareth L. ; Wiebe, Peter H.

A key hypothesis guiding the U.S. Southern Ocean Global Ocean Ecosystems Dynamics (U.S. SO GLOBEC) program is that deep across-shelf troughs facilitate the transport of warm and nutrient-rich waters onto the continental shelf of the Western Antarctic Peninsula, resulting in enhanced winter production and prey availability to top predators. We tested aspects of this hypothesis during austral winter by assessing the distribution of the resident pack-ice top predators in relation to these deep across-shelf troughs and by investigating associations between top predators and their prey. Surveys were conducted July-August 2001 and August-September 2002 in Marguerite Bay, Antarctica, with a focus on the main across-shelf trough in the bay, Marguerite Trough. The common pack-ice seabird species were snow petrel (Pagodroma nivea, 1.2 individuals km-2), Antarctic petrel (Thalassoica antarctica, 0.3 individuals km-2), and Adélie penguin (Pygoscelis adeliae, 0.5 individuals km-2). The most common pack-ice pinniped was crabeater seal (Lobodon carcinophagus). During both winters, snow and Antarctic petrels were associated with low sea ice concentrations independent of Marguerite Trough, while Adélie penguins occurred in association with this trough. Krill concentrations, both shallow and deep, were also associated with Adélie penguin and snow petrel distributions. During both winters, crabeater seal occurrence was associated with deep krill concentrations and with regions of lower chlorophyll concentration. The area of lower chlorophyll concentrations occurred in an area with complex bathymetry close to land and heavy ice concentrations. Complex or unusual bathymetry via its influence on physical and biological processes appears to be one of the keys to understanding how top predators survive during the winter in this Antarctic region.

Fraser William R.

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