How to fill the biodiversity data gap:Is it better to invest in fieldwork or curation?

Data gaps and biases are two important issues that affect the quality of biodiversity information and downstream results.Understanding how best to fill existing gaps and account for biases is necessary to improve our current information most effectively.Two current main approaches for obtaining and improving data include(1)curation of biological collections,and(2)fieldwork.However,the comparative effectiveness of these approaches in improving biodiversity data remains little explored.We used the Flora de Bogota project to study the magnitude of change in species richness,spatial coverage,and sample coverage of plant records based on curation versus fieldwork.The process of curation resulted in a decrease in species richness(synonym and error removal),but it significantly increased the number of records per species.Fieldwork contributed to a slight increase in species richness,via accumulation of new records.Additionally,curation led to increases in spatial coverage,species observed by locality,the number of plant records by species,and localities by species compared to fieldwork.Overall,curationwas more efficient in producing new information compared to fieldwork,mainly because of the large number of records available in herbaria.We recommend intensive curatorial work as the first step in increasing biodiversity data quality and quantity,to identify bias and gaps at the regional scale that can then be targeted with fieldwork.The stepwise strategy would enable fieldwork to be planned more costeffectively given the limited resources for biodiversity exploration and characterization.

Grazing Pressure and Plant Functional Types in Puna Highlands,Northwestern Argentina

The Puna grasslands support grazing systems that produce meat and wool in multi-species herds,especially from llama(Lama glama)and sheep.However,it is yet unknown whether grazing pressure can modify grassland structure and Plant Functional Types diversity and cover in Puna grasslands.We analyzed the relationship between grazing pressure and Plant Functional Types by comparing transects located near stockyards(high grazing pressure)and far from them(low pressure)and by evaluating the relationship between the Plant Functional Types cover to a Grazing Pressure Index(GPI).This index incorporates the heterogeneity of traditional pastoral management.At two ecological sites(Ciénego and Tolar),we sampled paired transects(near-far).Plots near and far from corrals were similar in all the variables measured except for plots in Tolar,which tend to have higher total cover,possibly due to fecal fertilization near stockyards.Furthermore,we recorded an increase in total cover and grass cover at higher GPI in Ciénego,while in Tolar we found lower values of total cover and herbaceous dicotyledonous cover at intermediate intensities of GPI.The only negative relationship found was the cover of clonal and non-clonal shrubs,possibly explained by the greater use of these shrubs as firewood near stockyards.In summary,our study does not show important changes in Plant Functional Types as a function of grazing pressure in the studied grasslands probably because grazing pressure is diluted or diminished when livestock rotates in different areas and grazing durations vary.Finally,the long grazing history with which the Puna has evolved could also contribute to the co-structuration between native vegetation and livestock farming.

Long-term trends in the abundance and breeding performance in Adélie penguins:the Argentine Ecosystem Monitoring Program

In this work,we report long-term trends in the abundance and breeding performance of Adélie penguins(Pygoscelis adeliae)nesting in three Antarctic colonies(i.e.,at Martin Point,South Orkneys Islands;Stranger Point/Cabo Funes,South Shetland Islands;and Esperanza/Hope Bay in the Antarctic Peninsula)from 1995/96 to 2022/23.Using yearly count data of breeding groups selected,we observed a decline in the number of breeding pairs and chicks in crèche at all colonies studied.However,the magnitude of change was higher at Stranger Point than that in the remaining colonies.Moreover,the index of breeding success,which was calculated as the ratio of chicks in crèche to breeding pairs,exhibited no apparent trend throughout the study period.However,it displayed greater variability at Martin Point compared to the other two colonies under investigation.Although the number of chicks in crèche of Adélie penguins showed a declining pattern,the average breeding performance was similar to that reported in gentoo penguin colonies,specifically,those undergoing a population increase(even in sympatric colonies facing similar local conditions).Consequently,it is plausible to assume a reduction of the over-winter survival as a likely cause of the declining trend observed,at least in the Stranger Point and Esperanza colonies.However,we cannot rule out local effects during the breeding season affecting the Adélie population of Martin Point.

Review of the Cretaceous avian diversity of Antarctica:a changing scenario for the evolution of early Neornithine birds

The worldwide record of Cretaceous Neornithes and Neornithine-like birds is both controversial and poorly understood.However,in recent years,the Antarctic continent has yielded a substantial number of Maastrichtian avian specimens,contributing significantly to our understanding of the early evolution of this group.Simultaneously,the keen interest and collaborative efforts of various paleornithologists have resulted in a wealth of knowledge,which we have thoroughly reviewed,updated,and discussed in the context of recent discoveries.

Contributions to the knowledge of Antarctodon sobrali(Mammalia:Astrapotheria)from the Eocene of Antarctica

The Astrapotheria constitutes one of the five orders of extinct South American native ungulates,with a fossil record that also extends to the Eocene of the Antarctic Peninsula.In contrast to the abundant specimens known for litoptern Sparnotheriodontidae and metatherians,astrapotheres are represented by scant remains assigned to the endemic Antarctodon sobrali and indeterminate astrapotheres,restricted to levels 35C_(u0)and 35n of the Cucullaea I Allomember of the La Meseta Formation.The discovery of alower molar assignable to this species in the Eocene levels of Seymour(Marambio)Island,enables a revision of the diagnosis and the homologies of the dental characters used to describe this taxon.A reanalysis of its phylogenetic relationships reveals the nearly simultaneous presence of basal astrapotheres in the early Eocene of Itaboraí(Brazil),Patagonia,and West Antarctica.These taxa are characterized by lacking dental specializations usually associated with more abrasive diets like terminal forms of Uruguaytheriinae and Astrapotheriinae.Antarctodon appears to have thrived on the Antarctic continent during the Early Eocene Climatic Optimum within the paleoclimatic context of a hot-house world.Unlike present conditions in Antarctica where no terrestrial mammals inhabit,the early Eocene climate was characterized by warmer temperatures and a biologically diverse environment rich in primary producers,dominated by Nothofagus forests,encompassing both deciduous and evergreen forests,which supported a diverse assemblage of continental vertebrates.

Environmental changes affect picoplanktonic composition in Antarctic Peninsula ponds

Antarctic Peninsula is experiencing one of the largest global warming events worldwide.Shallow water bodies generated by the melting of snow in summer are numerous,and they might act as sentinels of climate change due to their rapid response and ability to integrate catchment information.Shifts in climate can influence the structure of microbial communities which dominate these freshwaters ecosystems.Here,we characterize three ponds at Cierva Point(Antarctic Peninsula)by examining their physico-chemical and morphological characteristics and we explored how different factors modify the structure of the microbial community.We studied the abundance and biomass of heterotrophic bacteria,picocyanobacteria and picoeukaryote algae during January and February of two consecutive summers(2017 and 2018).We found that ponds had different limnological characteristics,due to their location,geomorphological features and presence of the surrounding flora and fauna.Physico-chemical parameters as well as microbial community differed between ponds,months and years.In 2017,most ponds were oligo to mesotrophic states.The larger accumulated rainfall(as a result of environmental changes on the Antarctic Peninsula)during 2018,particularly in February,causes nutrient runoff into water bodies.This affects those ponds with the highest seabird circulation,such as gentoo penguin,increasing eutrophication.As a result,picoplanktonic abundances were higher,and the community structure shifts to a largely heterotrophic bacteria dominated one.These results suggest that these communities could act as sentinels to environmental changes,anticipating a future with mostly hypertrophic ponds.

Middle Eocene chondrichthyan fauna from Antarctic Peninsula housed in the Museo de La Plata,Argentina

In recent years,the taxonomy and systematics of the cartilaginous fish taxa from the Eocene La Meseta Formation of Seymour(Marambio)Island,Antarctica have been extensively discussed in a series of papers,resulting in a complete revision of the Antarctic Eocene ichthyofauna housed in the Vertebrate Paleontology collection of the Museo de La Plata,Argentina.This collection constitutes one of the largest and taxonomically most diverse in the world,with approximately 20000 specimens,which provides a solid database used for the analysis of qualitative and quantitative chondrichthyan taxonomic composition.The information provided herein might be useful to understand the sudden decline in chondrichthyan taxonomic diversity towards the top of La Meseta Formation as well as its potential relationship with environmental changes during the Eocene.

The first record of dermochelyid turtles in the Eocene of Tierra del Fuego:new insights on the evolution of the Weddellian faunas

The Antarctic Paleogene marine fossil record has been the key to reconstructing the evolution of the Weddellian Sea and final dismemberment of Southern Gondwana.In this context,Eocene marine vertebrates from Seymour(Marambio)Island have provided valuable information.We present the first Eocene record of marine reptiles from the southern Atlantic Coast of South America.This corresponds to several postcranial turtle remains represented by a proximal end of the right humerus,three caudal and one thoracic vertebrae,a fragment of the left pubis,and ten ossicles of the dorsal carapace,coming from the Leticia Formation(late-mid Eocene)at Cabo Tiburones,Tierra del Fuego,Argentina.These materials show severalfeatures such as the size and general morphology of the humerus and vertebrae,and the presence of relatively small,irregular,smooth,and unkeeled ossicles,which allow us to assign them to Dermochelyidae indet.Dermochelyids are a cosmopolitan group ofcryptodiran turtles,registered from the late Cretaceous up to the recent,with some physiological-biological peculiarities(e.g.,endothermy and an exclusive jellyfish-based diet)and characterized by the presence of an osseous carapace formed by ossicles.The new finding from the Leticia Formation is an addition to the scarce and extremely fragmentary record of Eocene dermochelyids from the southern seas like those from the La Meseta and Submeseta formations(Antarctica)and the Waihao and Burnside formations(New Zealand).This new information allows us to discuss the presence of these turtles in such high latitudes in the past and its implication in the evolution of the Weddellian fauna.

Thermodynamic analysis, synthesis, characterization, and evaluation of 1-ethyl-3-methylimidazolium chloride: Study of its effect on pretreated rice husk

This work is focused on the determination of the optimal reaction conditions to synthesize the ionic liquid 1-ethyl-3-methylimidazolium chloride([EMIM][Cl]) and assess its suitability for the pretreatment of rice husk. The modified UNIFAC(UNIversal quasi-chemical Functional-group Activity Coefficients)approach for ionic liquids is used to develop a thermodynamic model that describes the reactive system methylimidazole(MIM), chloroethane(C_(2)H_(5)Cl) and [EMIM][Cl]. The model allows to study the phase equilibria coexistence(vapor–liquid equilibria and solid–liquid equilibria) and yields the theoretically optimal conditions to synthesize the ionic liquid. The model predictions are validated with the available experimental and reported data. By implementing the developed model, a simple way to synthesize ionic liquid [EMIM][Cl] was found allowing to study its influence on the structure and morphology of pretreated rice husk. The lignocellulosic materials involved in this study are characterized by their composition, enzymatic digestibility, scanning electron microscopy, and crystallinity. Compared to untreated material, [EMIM][Cl]-pretreated rice husk produces cellulose that can be efficiently enzymatic hydrolyzed with high sugar yields. This work offers a suitable methodology to include the synthesis and thermodynamics of the solvent media within the design of low-cost ionic liquids for lignocellulosic biomass pretreatment.

Omics analyses in citrus reveal a possible role of RNA translation pathways and Unfolded Protein Response regulators in the tolerance to combined drought, high irradiance, and heat stress

Environmental changes derived from global warming and human activities increase the intensity and frequency of stressful conditions for plants.Multiple abiotic factors acting simultaneously enhance stress pressure and drastically reduce plant growth,yield,and survival.Stress combination causes a specific stress situation that induces a particular plant response different to the sum of responses to the individual stresses.Here,by comparing transcriptomic and proteomic profiles to different abiotic stress combinations in two citrus genotypes,Carrizo citrange(Citrus sinensis×Poncirus trifoliata)and Cleopatra mandarin(Citrus reshni),with contrasting tolerance to different abiotic stresses,we revealed key responses to the triple combination of heat stress,high irradiance and drought.The specific transcriptomic response to this stress combination in Carrizo was directed to regulate RNA metabolic pathways and translation processes,potentially conferring an advantage with respect to Cleopatra.In addition,we found endoplasmic reticulum stress response as common to all individual and combined stress conditions in both genotypes and identified the accumulation of specific groups of heat shock proteins(HSPs),such as small HSPs and HSP70s,and regulators of the unfolded protein response,BiP2 and PDIL2-2,as possible factors involved in citrus tolerance to triple stress combination.Taken together,our findings provide new insights into the acclimation process of citrus plants to multiple stress combination,necessary for increasing crop tolerance to the changing climatic conditions.

Evaluation of the potential of coastal cliffs as geosites for the promotion of geotourism

Coastal zones, with their significant geodiversity, are vital areas for geotourism. Effective management is crucial to harness the geological interest of these sites as geotourism resources while ensuring their conservation. ManabíProvince is one of the most representative regions along the Ecuadorian coast due to its beaches and coastal cliffs, offering a wealth of tourist attractions and cultural elements. This study aims to evaluate the geosite potential of six cliffs in ManabíProvince through quantitative and qualitative analyses to propose geotourism promotion strategies. The methodology involves (i) inventory and characterisation of the cliffs, (ii) assessment of the sites by the Spanish Inventory of Places of Geological Interest method (IELIG), and (iii) qualitative evaluation through focus group discussions and Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis. The results reveal that all six sites boast diverse geological assets, including geomorphological, stratigraphic, sedimentological, and tectonic elements. They are characterised by “high ”scientific, didactic, and tourist interest, while also being sus- ceptible to degradation due to natural and anthropic threats. The SWOT analysis demonstrates that the valuable geological and geomorphological heritage of potential geosites provides an opportunity to foster geotourism and boost the province’s economy, incorporating geoconservation and geoeducation strategies. This study proposes a georoute called “Ruta Acantilados del Sol ”, a 245 km journey encompassing all six sites, incorporating diverse tourist and cultural activities. Our research lays the foundation for fostering geotourism along the Manabícoast and strengthening the connection between nature, heritage, and the welfare of residents within a global resilience plan.

Acoustic contamination assessment during the transition between the COVID-19 restrictions and reactivation:A exploratory analysis in Guayaquil

Noise pollution is becoming a critical health risk for city life.In 2020,the COVID-19 pandemic forced many cities to implement several mobility restrictions.These restrictions changed human activity patterns and decreased the noise levels and noise pollution that often affect urban settings.As the number of infections decreased,so did the outdoor activities,influencing the population’s perception of noise.This paper aims to evaluate the changes in noise levels associated with mobility restrictions between 2020 and 2021 in Guayaquil,Ecuador.This study used crowdsourcing with the help of smartphones and mobile applications to collect geo-referenced environmental noise data.The data was used to generate noise maps in different time frames.Finally,noise level maps were created using GIS-based tools to identify the urban areas that experienced the highest noise level variation during the study period.The results show that the most significant noise increase occurred at night.Furthermore,when analyzing noise level changes in different urban areas,the western area of Guayaquil was the one that experienced the most significant noise level variation.Findings inform the perception of noise pollution and could potentially serve as a reference for decision-makers during the proposal of public policies that ensure a better quality of life for its citizens.

济源盆地谭庄组(T_(2-3))上段湖相沉积及遗迹化石特征

济源市西南郊出露有中—上三叠统谭庄组,代表了济源中生代盆地充填的一部分。在湖相剖面中识别出六种岩相组成的两类相序,相序 1呈叠置的向上变粗的序列,由下到上由富有机质页岩 (相E,类型Ⅰ ),纹层粉砂岩 (相A)和水流波痕层理砂岩(相B)组成,记录了在温暖潮湿条件下常年性开放湖泊中小型河口坝三角洲的进积作用;相序 2缺少明显的垂直序列,由互层状细粒碳酸盐岩和粉砂岩(相C),变形层理和波浪改造砂岩 (相D),富有机质页岩(相E,类型Ⅱ)和粘土岩组成,虽然也代表了常年性开放浅水湖泊体系,但反映出很强的季节性气候控制特征。湖相剖面的相C中发育丰富的Skolithoslinearis组合,也反映出底层受季节性气候控制。文章深入探讨了该组上段浅湖沉积的环境演替及气候对沉积作用的控制作用,在湖泊演化过程中,很可能出现过几次水体分层。根据晚三叠世时期的古地理重建,推测谭庄组上段湖相沉积反映出的强烈季节性可以用潘加亚巨型季风影响的设想模式解释。

An overview of plant-autochthonous microorganisms and fermented vegetable foods

Fermented plant-based foods and beverages constitute foods of high nutritional and functional value with appreciated health beneficial effects.They represent a natural and sustainable alternative to counteract the large wastage of vegetables and fruits due to their short shelf life.Usually,the use of controlled fermentation process using autochthonous microorganisms adapted to their vegetable matrix is preferred instead of traditionally spontaneous fermentation to designing fermented vegetable foods with the desirable sensory,technological,nutritional and functional properties.This review summarizes the autochthonous microorganisms selected as starters for the successful fermentation of vegetables and fruits.The main beneficial properties of autochthonous starters and fermented vegetable products with a focus on human health are revised.

In vitro germination and shoot proliferation of the threatened species Cinchona officinalis L(Rubiaceae).

Cinchona officinalis （Rubiaceae） is an endemic species of the Loja Valley in southern Ecuador with medicinal uses. Because of over-exploitation in the nine- teenth century and more recent disturbances to its ecosystem, C. officinalis populations are threatened. Currently, natural regeneration of the populations is low, despite its high plant regeneration and seed formation capacity. In the present study, an efficient protocol for germination, shoot proliferation and plantlets regeneration was developed for this species. Phenolic content and germination rate of C. officinalis seeds were compared with a control species, C. pubescens. Nodal segments from seedlings of C. officinalis were cultured on Gamborg medium supplemented with different combinations of plant growth regulators. Because the phenol content is high in C. officinalis, the phenolic should be removed with hydrogen peroxide or water washes to stimulate germination. Shoots and callus developed from nodal segments within 45 days using most of the tested combinations of plant growth regulators. The best rates of shoot proliferation, callus formation and adventitious buds were obtained in medium supplemented with 5.0 mg L^-1 6-benzyl-aminopurine and 3.0 mg L^-1 indole- 3-butyfic acid.

Microbial Fermentation Patterns, Diarrhea Incidence, and Performance in Weaned Piglets Fed a Low Protein Diet Supplemented with Probiotics

To evaluate the effects of dietary protein levels and probiotic supplementation on microbial intestinal fermentation, diarrhea incidence, and performance in weaned piglets, 162 piglets were randomly assigned to three treatments: high-protein diet (20%), with antibiotics (HPa);high-protein diet (20%), without antibiotics (HP);and low-protein diet, without antibiotics but with probiotics (LPpb). Piglets and feed were weighed weekly to calculate the average daily gain (ADG), average daily feed intake (ADFI), and gain: feed ratio (G:F). Four piglets per treatment were killed on day 21 postweaning to collect ileal and colon digesta for measurement of short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs), lactic acid (LA), and ammonia (AM). In the digesta collected from the ileum and colon, piglets fed the HPa diet had the lowest concentration of volatile fatty acids. Additionally, the HP diet produced the highest concentration of BCFAs, while the LPpb diet produced moreacetic, propionic, and butyric acids than the HPa and HP diets. Piglets fed the HP diet had higher incidence and severity of diarrhea than piglets fed LPpb and HPa diets, and similar values were observed between these two groups. The second week postweaning was the most critical for diarrhea measurements;during the second week, animals had higher incidence and severity of diarrhea. Piglets fed the HPa and LPpb diets had similar ADGs, while those fed the HP diet had the poorest ADG. Similar results were observed with ADFI and G:F. A low-protein diet supplemented with probiotics changed the fermentation profile, reducing toxic metabolites, promoting gut health, decreasing the incidence and severity of postweaning diarrhea, and improving the performance of piglets.

The fossil record of Antarctic land mammals:commented review and hypotheses for future research

The fossil record of terrestrial mammals in Antarctica is temporally and geographically constrained to the Eocene outcrops of La Meseta and Submeseta formations in Seymour(Marambio)Island in West Antarctica.The faunal assemblage indicates a clear South American imprint since all the groups have a close phylogenetic relationship with Cretaceous and Paleogene mammals from Patagonia.Despite the presence of several mammalian taxonomic groups:Dryolestida,Gondwanatheria,Eutheria and Metatheria,the presence of other major mammalian taxa should be expected and will probably be confirmed by new findings.Placental mammals with an inferred body mass between 10 to 400 kg in size,are represented by xenarthrans,and two groups of the so called South American native ungulates:Astrapotheria and Litopterna.The Metatheria are the smaller(less than 1 kg)and most abundant components of the fauna.Marsupials are represented by derorhynchid ameridelphians,several microbiotherian australidelphians(both microbiotheriids and woodburnodontids),and?glasbiid prepidolopod and polydolopid polydolopimorphians.Plus,there are remains of several mammalian teeth of indeterminate phylogenetic affinities.The present knowledge of the Southern Hemisphere mammalian evolution and paleogeographic change through time,indicates that Antarctica played a major role for land mammals,at least since the Jurassic.The actual representation of Paleogene terrestrial mammals in Antarctica is most probably biased,as all the evidence indicates that australosphenidan mammals should be present in this continent since the Jurassic.

Hydrothermal Synthesis and Characterization of Europium-doped Barium Titanate Nanocrystallites

Barium titanate nanocrystallites were synthesized by a hydrothermal technique from barium chloride and tetrabutyl titanate. Single-crystalline cubic perovskite Ba TiO_3 consisting of spherical particles with diameters ranging from 10 to 30 nm was easily achieved by this route. In order to study the influence of the synthesis process on the morphology and the optical properties, barium titanate was also prepared by a solid-state reaction. In this case, only the tetragonal phase which crystallizes above 900 was observed. High-temperature X-ray diffraction measurements were performed to investigate the crystallization temperatures as well as the particle sizes via the Scherrer formula. The lattice vibrations were evidenced by infrared spectroscopy. Eu^(3+)was used as a structural probe, and the luminescence properties recorded from Ba TiO_3 :Eu^(3+)and elaborated by a solid-state reaction and hydrothermal process were compared. The reddish emission of the europium is increased by the nanometric particles.

Development of a microcomposite with single-walled carbon nanotubes and Nd_2O_3 for determination of paracetamol in pharmaceutical dosage by adsorptive voltammetry

This study presents for the first time a new composite of carbon paste(CP), single-walled carbon nanotubes(SWCNTs) and Nd2 O3(NdOX). This versatile composite(NdOX-SWCNT/CPE) was applied to the oxidation of paracetamol(PCM). The newly formed surface was characterized by scanning electron microscopy(SEM), electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV). The results showed greater conductivity and a higher surface area for the composite than those of the carbon paste alone. Moreover, the anodic peak currents for PCM increased from 1.6 to 3.6 m A with CPE and NdOXSWCNT/CPE, indicating an increase of nearly 51.0% for the anodic peak current. On the other hand, the anodic peak potentials shifted from 0.67 to 0.57 V. The detection limits were 0.05 mmol/L with NdOXSWCNT/CPE and 0.50 mmol/L with SWCNT/CPE. The relative standard deviations(RSDs) were 1.5%(n=7). The accuracy and interference of the methods were evaluated with a urine chemistry control spiked with known quantities of PCM, uric acid, dopamine, ascorbic acid, caffeine, acetylsalicylic acid,tartrazine, sunset yellow, allure red, rutin, morin and metal ions. Finally, the novelty and usefulness of the composite were evaluated to quantify PCM in pharmaceutical dosage forms such as tablets, powders and syrups for children.

Long-term study of at-sea distribution of seabirds and marine mammals in the Scotia Sea, Antarctica

The Scotia Sea is one of the most biologically rich regions of Antarctica, and it hosts a large community of upper trophic-level predators. Long-term at-sea monitoring provides valuable information on the Antarctic marine ecosystem and relationships among top predators. This paper presents the results of at-sea monitoring of seabirds and cetaceans over five consecutive summer seasons （2010--2014） in the Scotia Sea, Antarctica. A total of 11 656 flying birds belonging to 24 species were recorded in 884 ten-minute counts. Six Procellariiformes species were abundant： Black-browed Albatross, Cape Petrel, Southern Fulmar, Antarctic Prion, Wilson＇s Storm-petrel, and Black-bellied Storm-petrel. Only three of these species accounted for 82% of the total abundance： Antarctic Prion （40%）, Southern Fulmar （22%）, and Cape Petrel （20%）. A total of 678 baleen whales belonging to five species were recorded along a sampling effort of 2 351 nautical miles： Humpback, Sei, Southern Right, Fin, and Minke whales, which had different abundances during the study. The Fin Whale had the highest mean encounter rate for the 5 years （0.29 whales per nautical mile）, followed by the Humpback Whale （0.09 whales per nautical mile）. Annual dissimilarity in abundance of both seabirds and cetaceans occurred in conjunction with changes in the sea surface temperature and ice cover, showing the dependence of top predators on environmental changes. The largest aggregations of all top predators （seabirds and cetaceans） were recorded in two regions, west and south of the South Orkney Islands, suggesting important prey availability （especially krill） in those areas.