The Palmer LTER: A Long-Term Ecological Research Program at Palmer Station, Antarctica

Smith, Raymond C.; Baker, Karen S.; Fraser, William R.; Hofmann, Eileen E.; Karl, David M.; Klinck, John M.; Quetin, Langdon B.; Prézelin, Barbara B.; Ross, Robin M.; Trivelpiece, Wayne Z.; Vernet, María

doi:10.5670/oceanog.1995.01

Cited by 120 publications

(92 citation statements)

References 27 publications

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“…However, they are still limited in their ability to detect some physical changes, such as sea ice thickness and Chl a concentration in waters covered by ice (Massom et al, 2006;Hobbs et al, 2016). There are very few places that have long-term monitoring programs to detect changes in the physical and biological environment (such as the Palmer-Long Term Ecological Research program, Smith et al, 1995) and few of these have collected data for a sufficient duration to detect trends in phytoplankton against the background of natural variation. Decades long monitoring programs should be established as a matter of urgency to detect changes in SO phytoplankton abundance, production, and composition.…”

Section: Resultsmentioning

confidence: 99%

Southern Ocean Phytoplankton in a Changing Climate

2017

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Phytoplankton are the base of the Antarctic food web, sustain the wealth and diversity of life for which Antarctica is renowned, and play a critical role in biogeochemical cycles that mediate global climate. Over the vast expanse of the Southern Ocean (SO), the climate is variously predicted to experience increased warming, strengthening wind, acidification, shallowing mixed layer depths, increased light (and UV), changes in upwelling and nutrient replenishment, declining sea ice, reduced salinity, and the southward migration of ocean fronts. These changes are expected to alter the structure and function of phytoplankton communities in the SO. The diverse environments contained within the vast expanse of the SO will be impacted differently by climate change; causing the identity and the magnitude of environmental factors driving biotic change to vary within and among bioregions. Predicting the net effect of multiple climate-induced stressors over a range of environments is complex. Yet understanding the response of SO phytoplankton to climate change is vital if we are to predict the future state/s of the ecosystem, estimate the impacts on fisheries and endangered species, and accurately predict the effects of physical and biotic change in the SO on global climate. This review looks at the major environmental factors that define the structure and function of phytoplankton communities in the SO, examines the forecast changes in the SO environment, predicts the likely effect of these changes on phytoplankton, and considers the ramifications for trophodynamics and feedbacks to global climate change. Predictions strongly suggest that all regions of the SO will experience changes in phytoplankton productivity and community composition with climate change. The nature, and even the sign, of these changes varies within and among regions and will depend upon the magnitude and sequence in which these environmental changes are imposed. It is likely that predicted changes to phytoplankton communities will affect SO biogeochemistry, carbon export, and nutrition for higher trophic levels.

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Section: Resultsmentioning

confidence: 99%

Southern Ocean Phytoplankton in a Changing Climate

2017

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“…Research on Adélie penguins began in the early 1970s (Parmelee 1992), and since the late 1980s has continued in support of 2 long-term research and monitoring programs. An approach shared by these programs is the use of penguin foraging ecology as an indicator of krill variability (see Fraser et al 1988, Smith et al 1995, and indeed many studies show that seabirds are good proxy indicators of the spatial and temporal variance associated with the structure of their prey populations (Sunada et al 1981, Cairns 1987, Furness & Nettleship 1991, Hatch & Sanger 1992, Ainley et al 1993, Croxall et al 1999, Reid et al 1999a. The penguin data analyzed include a time series on Adélie penguin foraging trip durations (8 yr) and another on diets (13 yr), which we use as proxies to investigate possible ice-induced changes in krill availability and population size-class structure, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Siegel & Loeb 1995, 1998 to test hypotheses about changes in krill availability suggested by our analyses. The Elephant Island data were used in lieu of Palmer Station data because the time series on krill abundance for the latter does not include the first 2 yr of our 8 yr foraging trip duration time series (see Smith et al 1995). Piece-wise linear regression models were used to investigate relationships between the Elephant Island krill-abundance trends and the foraging responses of Adélie penguins at Palmer Station.…”

Section: Methodsmentioning

confidence: 99%

A predator's perspective on causal links between climate change, physical forcing and ecosystem response

Fraser¹,

Hofmann²

2003

Mar. Ecol. Prog. Ser.

231

242

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ABSTRACT:The mechanisms by which variability in sea ice cover and its effects on the demography of the Antarctic krill Euphausia superba cascade to other ecosystem components such as apex predators remain poorly understood at all spatial and temporal scales, yet these interactions are essential for understanding causal links between climate change, ecosystem response and resource monitoring and management in the Southern Ocean. To address some of these issues, we examined the longterm foraging responses of Adélie penguins Pygoscelis adeliae near Palmer Station, western Antarctic Peninsula, in relation to ice-induced changes in krill recruitment and availability. Our results suggest that (1) there is a direct, causal relationship between variability in ice cover, krill recruitment, prey availability and predator foraging ecology, (2) regional patterns and trends detected in this study are consistent with similar observations in areas as far north as South Georgia, and (3) largescale forcing associated with the Antarctic Circumpolar Wave may be governing ecological interactions between ice, krill and their predators in the western Antarctic Peninsula and Scotia Sea regions. Another implication of our analyses is that during the last 2 decades in particular, krill populations have been sustained by strong age classes that emerge episodically every 4 to 5 yr. This raises the possibility that cohort senescence has become an additional ecosystem stressor in an environment where ice conditions conducive to good krill recruitment are deteriorating due to climate warming. In exploring these interactions, our results suggest that at least 1 'senescence event' has already occurred in the western Antarctic Peninsula region, and it accounts for significant coherent decreases in krill abundance, predator populations and predator foraging and breeding performance. We propose that krill longevity should be incorporated into models that seek to identify and understand causal links between climate change, physical forcing and ecosystem response in the western Antarctic Peninsula region.

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“…Most studies have concentrated on the Bransfield Strait (Brandini & Kutner 1986, Holm-Hansen et al 1994, Priddle et al 1994, Kang & Lee 1995, Bidigare et al 1996, Lorenzo et al 2002, which has complex hydrographic characteristics due to the mixing of water masses of the Drake Passage, Weddell Sea and Bellinghausen Sea (Niiler et al 1991, Hofmann & Klinck 1998. South of Bransfield Strait, research was sporadic before the establishment of the 'Palmer Long-Term Ecological Research (LTER) Program' (Smith et al 1995, Baker et al 1996, which has been conducting an integrated study of the marine pelagic ecosystem in an area between Anvers Island and Marguerite Bay since 1990 (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Phytoplankton spatial distribution patterns along the western Antarctic Peninsula (Southern Ocean)

Garibotti¹,

Vernet²,

Ferrario³

et al. 2003

Mar. Ecol. Prog. Ser.

160

117

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This paper describes spatial distribution patterns of the phytoplankton community (composition, cell abundance and biomass concentration) in relation to local environmental conditions in the Southern Ocean. Sampling was performed during summer 1997 off the coast of the western Antarctic Peninsula between Anvers Island and Marguerite Bay. Phytoplankton was characterized by relatively low biomass throughout most of the study area and was dominated by nanoalgae (< 20 µm). Phytoplankton varied along an on-offshore gradient, with decreasing total cell abundance, chlorophyll a (chl a) concentration and carbon biomass toward the open ocean. Chl a concentration showed surface or subsurface maxima in coastal and middle-shelf waters, and deep maxima between ~40 and 100 m in oceanic waters. Across-shelf variability in phytoplankton correlated with vertical stability in the water column, which appears to be the major parameter affecting phytoplankton community structure in the area. We hypothesize that the deep chl a maximum offshore may be associated with iron limitation in near-surface waters and higher iron concentration in 'winter waters' (subsurface remnant of Antarctic Surface Waters). On a smaller spatial scale, a cluster analysis showed great regional variability in phytoplankton assemblages. The area was divided into 4 main regions based on differences in the phytoplankton composition and concentration. Three peaks in phytoplankton abundance were found on a north-to-south gradient in near-shore waters: a Cryptomonas spp. bloom near Anvers Island, a small unidentified phytoflagellate bloom in Grandidier Channel, and a diatom bloom in Marguerite Bay. These assemblages resemble different stages of the phytoplankton seasonal succession, and may be related to the progressive sea-ice retreat, which might have regulated the timing of the onset of the phytoplankton seasonal succession in a north-south gradient. Biological environmental factors, such as seeding of the water column by epontic algae and selective zooplankton herbivory, are hypothesized to affect community composition in coastal regions. We conclude that large-scale variability in phytoplankton community structure is related to water column physical conditions and possibly iron availability, while mesoscale variability, as seen in coastal waters, is more likely due to seasonal succession of different algae groups.

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The Palmer LTER: A Long-Term Ecological Research Program at Palmer Station, Antarctica

Cited by 120 publications

References 27 publications

Southern Ocean Phytoplankton in a Changing Climate

Southern Ocean Phytoplankton in a Changing Climate

A predator's perspective on causal links between climate change, physical forcing and ecosystem response

Phytoplankton spatial distribution patterns along the western Antarctic Peninsula (Southern Ocean)

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