A 1000-year record of Adélie penguin diets in the southern Ross Sea

2002 ◽  
Vol 14 (4) ◽  
pp. 327-332 ◽  
Author(s):  
MICHAEL POLITO ◽  
STEVEN D. EMSLIE ◽  
WILLIAM WALKER
Keyword(s):  
Ross Sea ◽  
Prey Selection ◽  
Ice Age ◽  
Adélie Penguin ◽  
Pleuragramma Antarcticum ◽  
Adelie Penguin ◽  
Radiocarbon Dates ◽  
Antarctic Silverfish ◽  
The Antarctic

Non-krill prey remains were recovered from ornithogenic sediments at three active Adélie penguin colonies on Ross Island, to assess long-term dietary trends in this species. Radiocarbon dates place the age of these deposits from a maximum of 947 years ago to the present. We identified 12 taxa of fish and two of squid with the Antarctic silverfish (Pleuragramma antarcticum) as the most abundant prey species represented at all sites. In addition, silverfish have decreased in importance in Adélie penguin diet over the past 600 years, perhaps in response to climate change since the onset of the Little Ice Age, though it remains much more abundant in current penguin diet in the Ross Sea than in the Antarctic Peninsula. Other prey taxa reflect the diversity of prey selection by Adélie penguins in Antarctica.

Influence of environmental conditions on spatial distribution and abundance of early life stages of Antarctic silverfish,Pleuragramma antarcticum(Nototheniidae), in the Ross Sea

2010 ◽  
Vol 22 (3) ◽  
pp. 243-254 ◽  
Author(s):  
Mario La Mesa ◽  
Barbara Catalano ◽  
Aniello Russo ◽  
Silvio Greco ◽  
Marino Vacchi ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Early Life ◽  
General Circulation ◽  
Ross Sea ◽  
Life Stages ◽  
Early Life Stages ◽  
Pleuragramma Antarcticum ◽  
Antarctic Silverfish ◽  
The Antarctic ◽  
Western Ross Sea

AbstractThe Antarctic silverfishPleuragramma antarcticumBoulenger is the dominant fish species in the high Antarctic zone, playing a key role in the Ross Sea midwater shelf ecosystem. Unlike other notothenioids, it is holoplanktonic species, spending its entire life cycle in the water column. Early life stages ofP. antarcticumare generally found in the upper 200 m and their spatial distribution is largely affected by water masses and general circulation. To understand better the mechanisms involved in the geographical distribution of the Antarctic silverfish within the western Ross Sea, an analysis of abundance and distribution was carried out in relation to oceanographic conditions. Samples were collected in summer during the 1998, 2000 and 2004 Italian cruises, covering the majority of the western sector of the Ross Sea. Overall 127 stations were sampled using standard plankton nets for biological samples and CTD and XBT to record abiotic parameters. Although all surveys were in December–January, the yearly results differed in terms of relative abundance of larval developmental stages and of oceanographic characteristics. The 1997–98 samples were characterized by very low abundance overall and by the virtual absence of early larvae. In summers 1999–2000 and 2003–04 the abundance ofP. antarcticumwas one order of magnitude higher than in the earlier season. In 1999–2000 catches were mainly composed of pre-flexion larvae and late postlarvae, while in 2003–04 catches were made up of pre-flexion larvae and juveniles. In January 2000 the Ross Sea summer polynya was fully open as the pack ice was almost completely melted, whereas in January 1998 and 2004 the opening of the polynya was considerably delayed. As a consequence, a delay in phytoplankton blooms and a decrease in primary production were observed in the summer seasons 1998 and 2004 with respect to 2000. The spatial distribution of early life stages, that were confined to the continental shelf and shelf break of the Ross Sea, generally appeared to be positively influenced by transition zones (oceanographic fronts). In addition, most of catches were recorded on or in close proximity to the banks (Pennell, Mawson, Ross and Crary) that characterize the continental shelf of the Ross Sea. On the basis of present findings and literature data, a link between the general circulation in the western Ross Sea and the distribution pattern of the early life stages ofP. antarcticumhas been developed.

A 9000-year record of Adélie penguin occupation and diet in the Windmill Islands, East Antarctica

2005 ◽  
Vol 17 (1) ◽  
pp. 57-66 ◽  
Author(s):  
STEVEN D. EMSLIE ◽  
ERIC J. WOEHLER
Keyword(s):  
Population Cycles ◽  
East Antarctica ◽  
Adélie Penguin ◽  
Pygoscelis Adeliae ◽  
Pleuragramma Antarcticum ◽  
Fish Prey ◽  
Adelie Penguin ◽  
Radiocarbon Dates ◽  
Nest Site Fidelity ◽  
Windmill Islands

We investigated 17 abandoned Adélie penguin (Pygoscelis adeliae) colonies in the Windmill Islands, East Antarctica, in summer 2002/03. Forty radiocarbon dates on penguin bones and eggshells from 13 of these sites indicate a near continuous occupation by breeding penguins in this region for over 9000 years. These dates refine the recent geological record in this region and indicate that deglaciation of the northern islands occurred much earlier than previously suggested. Dietary remains from these sites include at least 23 taxa of cephalopods and teleost fish. Quantification of these remains indicates significant fluctuations in the relative abundance of two of the more common major prey taxa. The Antarctic silverfish (Pleuragramma antarcticum Boulenger) was the most common teleost prey during all time periods represented by the ages of the sites, but preservational factors may explain a gradual decrease in the remains of this species in increasingly older sites. The most common cephalopod in the sediments was the squid, Psychroteuthis glacialis Thiele, which occurred in low numbers in most sites except one (Site 75). An unusually high number of squid beaks preserved in Site 75, dating to approximately 5700–6100 cal. yr BP, does not correlate with a decrease in fish prey at that time. The high number of abandoned penguin colonies (> 200) in the Windmill Islands may be due to population cycles in the past in association with low nest-site fidelity and movement by breeding penguins to new sites within this region.

scholarly journals The rise and fall of an ancient Adélie penguin ‘supercolony’ at Cape Adare, Antarctica

2018 ◽  
Vol 5 (4) ◽  
pp. 172032 ◽  
Author(s):  
Steven D. Emslie ◽  
Ashley McKenzie ◽  
William P. Patterson
Keyword(s):  
Ross Sea ◽  
Open Water ◽  
Adélie Penguin ◽  
Water Access ◽  
Pygoscelis Adeliae ◽  
Adelie Penguin ◽  
Radiocarbon Dates ◽  
Cooling Period ◽  
Fast Ice ◽  
Marine Productivity

We report new discoveries and radiocarbon dates on active and abandoned Adélie penguin ( Pygoscelis adeliae ) colonies at Cape Adare, Antarctica. This colony, first established at approximately 2000 BP (calendar years before present, i.e. 1950), is currently the largest for this species with approximately 338 000 breeding pairs, most located on low-lying Ridley Beach. We hypothesize that this colony first formed after fast ice began blocking open-water access by breeding penguins to the Scott Coast in the southern Ross Sea during a cooling period also at approximately 2000 BP. Our results suggest that the new colony at Cape Adare continued to grow, expanding to a large upper terrace above Ridley Beach, until it exceeded approximately 500 000 breeding pairs (a ‘supercolony’) by approximately 1200 BP. The high marine productivity associated with the Ross Sea polynya and continental shelf break supported this growth, but the colony collapsed to its present size for unknown reasons after approximately 1200 BP. Ridley Beach will probably be abandoned in the near future due to rising sea level in this region. We predict that penguins will retreat to higher elevations at Cape Adare and that the Scott Coast will be reoccupied by breeding penguins as fast ice continues to dissipate earlier each summer, restoring open-water access to beaches there.

South Polar Skua breeding populations in the Ross Sea assessed from demonstrated relationship with Adélie Penguin numbers

Polar Biology ◽  
2016 ◽  
Vol 40 (3) ◽  
pp. 577-592 ◽  
Author(s):  
Deborah J. Wilson ◽  
Philip O’B. Lyver ◽  
Terry C. Greene ◽  
Amy L. Whitehead ◽  
Katie M. Dugger ◽  
...  
Keyword(s):  
Ross Sea ◽  
Adélie Penguin ◽  
Adelie Penguin ◽  
South Polar Skua ◽  
Breeding Populations ◽  
South Polar

scholarly journals A kleptoplastidic dinoflagellate and the tipping point between transient and fully integrated plastid endosymbiosis

2019 ◽  
Vol 116 (36) ◽  
pp. 17934-17942 ◽  
Author(s):  
Elisabeth Hehenberger ◽  
Rebecca J. Gast ◽  
Patrick J. Keeling
Keyword(s):  
Posttranscriptional Regulation ◽  
Ross Sea ◽  
Environmental Parameters ◽  
Tipping Point ◽  
Fully Integrated ◽  
Regulation Mechanisms ◽  
The Antarctic ◽  
Integration Levels ◽  
Genetic Integration

Plastid endosymbiosis has been a major force in the evolution of eukaryotic cellular complexity, but how endosymbionts are integrated is still poorly understood at a mechanistic level. Dinoflagellates, an ecologically important protist lineage, represent a unique model to study this process because dinoflagellate plastids have repeatedly been reduced, lost, and replaced by new plastids, leading to a spectrum of ages and integration levels. Here we describe deep-transcriptomic analyses of the Antarctic Ross Sea dinoflagellate (RSD), which harbors long-term but temporary kleptoplasts stolen from haptophyte prey, and is closely related to dinoflagellates with fully integrated plastids derived from different haptophytes. In some members of this lineage, called the Kareniaceae, their tertiary haptophyte plastids have crossed a tipping point to stable integration, but RSD has not, and may therefore reveal the order of events leading up to endosymbiotic integration. We show that RSD has retained its ancestral secondary plastid and has partitioned functions between this plastid and the kleptoplast. It has also obtained genes for kleptoplast-targeted proteins via horizontal gene transfer (HGT) that are not derived from the kleptoplast lineage. Importantly, many of these HGTs are also found in the related species with fully integrated plastids, which provides direct evidence that genetic integration preceded organelle fixation. Finally, we find that expression of kleptoplast-targeted genes is unaffected by environmental parameters, unlike prey-encoded homologs, suggesting that kleptoplast-targeted HGTs have adapted to posttranscriptional regulation mechanisms of the host.

Presence and distribution of serotonin in the stomach of the Antarctic silverfish Pleuragramma antarcticum

Polar Biology ◽  
2011 ◽  
Vol 35 (5) ◽  
pp. 795-799
Author(s):  
Chiara Gambardella ◽  
Laura Ghigliotti ◽  
Lorenzo Gallus ◽  
Eva Pisano ◽  
Grazia Tagliafierro ◽  
...  
Keyword(s):  
Pleuragramma Antarcticum ◽  
Antarctic Silverfish ◽  
The Antarctic

scholarly journals Gone fishing: Adélie penguin site-specific foraging tactics and breeding performance

2020 ◽  
Vol 32 (3) ◽  
pp. 199-209
Author(s):  
Silvia Olmastroni ◽  
Niccolò Fattorini ◽  
Francesco Pezzo ◽  
Silvano Focardi
Keyword(s):  
Ross Sea ◽  
Weather Conditions ◽  
High Energy ◽  
Adélie Penguin ◽  
Breeding Performance ◽  
Local Conditions ◽  
Seabird Species ◽  
Adelie Penguin ◽  
Breeding Parameters ◽  
Trade Offs

AbstractThe ecological drivers underlying breeding performance are expected to differ across the geographical range of seabird species, but few studies have compared trade-offs between colonies with different local conditions. During chick-rearing (2000–01), we compared the foraging trips, diet and breeding parameters of two Adélie penguin colonies in the Ross Sea, at Edmonson Point (EdPo; ~2000 breeding pairs) and Inexpressible Island (InIs; ~24 000 breeding pairs). Penguins from InIs travelled farther and performed longer feeding trips. The quantity of food brought to the nest was the same for the two colonies, but penguins from InIs brought more fish and less krill. Eggs hatched earlier at EdPo. Breeding success did not differ, but chick weight during hatching–fledging was greater at InIs. Despite worse weather conditions at InIs, the larger proportion of high-energy food brought by penguins from InIs (i.e. fish) may explain their offspring‘s better performance. In addition, the persistence of fast ice at EdPo may have led to greater energy expenditure of breeding individuals, possibly reducing chick growth. The greater intraspecific competition expected at InIs may have been reduced by longer foraging trips and/or counteracted by the more nutritious diet. Our findings reveal complex trade-offs between foraging effort and environmental constraints in determining the breeding performance of Adélie penguins.

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