Relationship of Radiolarian Assemblages to Sediment Types and Physical Oceanography in the Atlantic and Western Indian Ocean Sectors of the Antarctic Ocean
Jose A. Lozano, James D. Hays
The relative abundances of 18 selected taxonomic groups of Radiolaria were determined for 145 trigger-weight core-top samples collected between long 80°E and 55°W and lat 35°S and 60°S. Seventy-two samples were considered to represent nonreworked recent sediments. A factor analysis of these 72 samples resolved Antarctic, subantarctic, and subtropical assemblages, with distributions closely corresponding to the main surface water masses in the area. Using the technique of Imbrie and Kipp, paleoecologic equations have been developed to estimate surface-water temperatures for August (winter) and February (summer). Estimated temperatures range from near 20°C in the northern parts of the area to 0°C at the location of the southernmost cores. The standard error of estimate of the equations is less than 1.5°C. The CaCO3 content of the 145 surface-sediment samples shows that variations in the calcite compensation depth (CCD) for locations north of the Antarctic Polar Front depends mainly on varying dissolution. The CCD is about 4,800 m in the western basin of the Atlantic Ocean but is deeper than 5,200 m, at least locally, in the Indian Ocean. South of the Antarctic Polar Front the CCD is shallower than 3,700 m. Radiolaria are common in most samples, with the maximum number per gram of sediment being found in samples collected near or beneath the Antarctic Polar Front.
2
1990
Whale migration record
STONE, G., FLOREZ-GONZALEZ, L. & KATONA, S
SIR-We recently confirmed a new long distance migration record for mammals (apart from Homo sapiens). We found that a humpback whale (Megaptera novaeangliae) has migrated from the Antarctic peninsula region (64° 20'S; 62° 27'W) to Colombia (2° 57'N; 78° 12'W). The shortest swimming distance between these locations is more than 8,334 kilometres. We identified the whale at both locations using photographs of the distinctive ventral pigmentation on the tail flukes'. The whale was seen in Antarctica on 19 April and in Colombia on 28 August 1986. This is the first time that a hump back whale has been shown to cross the equator, and the first time an Antarctic humpback whale has been documented in South American waters. This finding has interesting implications for the possibility of migration between hemispheres. The match of pigmentation was found by comparing a catalogue of 32 hump backs identified from the Antarctic penin sula' and a collection of 86 identified off the coast of Colombia. The whale swam from Antarctica to Colombia in less than 5 months. Following the typical hump back migration strategy of spending sum mer in high latitudes and winter in low latitudes', this whale probably belongs to a population that feeds in Antarctica and breeds off the coast of Colombia. It is also possible that Antarctic penin sula humpback whales migrate up the eastern side of South America to the coast of Brazil, where there is another breeding ground. The swimming distance from the Antarctic peninsula to this area is shorter by more than 1,800 kilometres than to the Colombian site. This raises the interesting possibility that the Antarctic peninsula feeding grounds may be an area from which humpback whales can cross between the South Pacific Ocean and the South Atlantic Ocean. It is of interest to note that only 1,000 kilometres further north of our Colombian study site there is a site used during the breeding season by possibility that individuals occasionally might do so has important implications for gene flow, population differentiation and population management, and deserves further study.
3
2001
Genetic characterisation of the Colombian Pacific Coast humpback whale population using RAPD and mitochondrial DNA sequences
Megaptera novaeangliae, population structure, RAPD, mitochondrial DNA
Two genetic techniques were used to characterise the humpback whale population that overwinters annually off the Pacific Coast of Colombia. A preliminary study applied molecular techniques to an initial set of 32 biopsied or sloughed skin samples. Randomly Amplified Polymorphic DNA (RAPD) was used to provide an estimate of genetic variability and intra-population structure. Diversity of RAPD banding patterns suggest substantial genetic variability among sampled individuals. A parsimony tree was constructed using presence/absence of RAPD bands as characters, revealing three distinct groups: one of closely related individuals separate from two distinct clades within which relationships were unresolved. Mitochondrial DNA sequences for a consensus fragment 283 base pair in length of the rapidly evolving mitochondrial control region were then generated for the 32 samples and an additional 48 skin samples obtained from further fieldwork. An extensive comparative analysis was made with both published and unpublished control region sequences from humpback whales previously sampled in Colombia (n=64) and other regions in the Southern hemisphere (n=193) and the North Pacific (n=21). Haplotype diversity of the Colombian humpback population was high relative to other sampled populations, with 37 distinctive haplotypes, 11 of which were represented by a single animal. Both RAPD and mtDNA sequence data suggest further genetic substructure within the Colombian Pacific Coast humpback whale population. A large proportion of haplotypes (n=17) are shared with humpback whales sampled off the Antarctic Peninsula, suggesting a strong migratory connection between these regions as reported elsewhere. Only three haplotypes were shared with other Southern Hemisphere breeding grounds. Two Colombian haplotypes were common to populations from the North Pacific, supporting the hypothesis of a past or present East Pacific gene flow corridor between Northern and Southern Hemisphere populations.
Acanthodian remains occur in micaceous siltstone lenses (presumed to have been deposited during a marine incursion) in the Cuche Formation (?Frasnian) of northeast Colombia. The acanthodians are represented by patches of scales from climatiidid Nostolepis sp. cf. N. gaujensis and a fin spine and scales from a new diplacanthid. Type material of N. gaujensis is from the Frasnian Sventoji regional stage in the Baltic, and Nostolepis sp. cf. N. gaujensis has been recorded in the Frasnian of Iran, as well as from Colombia. The new diplacanthid taxon shows affinity to Baltic and Antarctic diplacanthids. The fauna thus shows possible links to both Gondwanan and Euramerican acanthodian assemblages.
5
2007
Migratory destinations of humpback whales from the Magellan Strait feeding ground, Southeast Pacific
Acevedo, J., Rasmussen, K., Félix, F., Castro, C., Llano, M., Secchi, E., Saborío M., Aguayo-Lobo, A., Ben Haase., et al.
Latitudinal preferences within the breeding range have been suggested for Breed- ing Stock G humpback whales that summer in different feeding areas of the eastern South Pacific. To address this hypothesis, humpback whales photo-identified from the Antarctic Peninsula and the Fueguian Archipelago (southern Chile) were com- pared with whales photo-identified from lower latitudes extending from northern Peru to Costa Rica. This comparison was performed over a time span that includes 18 austral seasons. A total of 238 whales identified from the Antarctic Peninsula and 25 whales from the Fueguian Archipelago were among those photo-identified at the breeding grounds. Our findings showed that humpback whales from each feeding area were resighted unevenly across the breeding grounds, which suggests a degree of spatial structuring in the migratory pathway. Humpback whales that feed at the Antarctic Peninsula were more likely to migrate to the southern breeding range between northern Peru and Colombia, whereas whales that feed at the Fueguian Archipelago were more likely to be found in the northern range of the breeding ground off Panama. Further photo-identification efforts and genetic sampling from poorly sampled or unsampled areas are recommended to confirm these reported con- nectivity patterns.
6
2008
Migratory round-trip of individually identified humpback whales at the Strait of Magellan: clues on transit times and phylopatry to destinations
Capella, J., Gibbons, J., Florez González, L., Llano, M., Valladares, C., Sabaj Diez, V. y Vilina, Y.
Colombia, humpback whales, migration, photo-identification, Strait og Magellan
Humpback whales undertake seasonal migration between productive high-latitude areas where they feed in summer and low-latitude tropical waters where mating and calving occur during winter. In the eastern south Pacific, the species breeds off Colombia and Ecuador, and feeds primarily in the western Antarctic Peninsula and in the waters of the Strait of Magellan (SM), recently described as a new feeding ground for humpback whales. Comparison of fluke photographs of 62 individuals from the SM obtained during the austral summer from 1999 to 2005 and 1,042 individuals from Colombia, provided conclusive matches for six individuals, with an overall interchange index of 0.093. Eight migratory trips between summer and winter grounds were registered for four whales during a complete migratory round-trip in consecutive years. The minimum distance traveled in a one-way trip ranged from 6,650 to 7,000 kill. The duration of the two fastest trips between these migratory destinations was 88 and 99 days, with a mean speed of migration of 76 and 67 kill day(-1) respectively. Five of the whales present in both areas were males and three mitochondrial DNA haplotypes were identified: EM-1 for three individuals, EM-2 for two and EM-3 for the last one, all of which have been previously described for humpback whales from Colombia. All six individuals were seen several days in each season in the SM (as many as 39 days in one case), with in average stay of 72 40 days (n = 20) per year, ranging from 3 to 125 days. On average, each of the six individuals was seen in the SM during 7 1 18% of the seven monitored summers. Three individuals were re-sighted in the SM six out of the seven surveyed years, during four to Six Consecutive years. These results provide the first direct evidence to include humpback whales that feed in the Strait of Magellan as part of the eastern south Pacific population of whales that feed off Colombian waters.
7
2012
Genetic diversity and population structure of humpback whales(Megaptera novaeangliae) from Ecuador based on mitochondrialDNA analyses
Félix, F., Caballero, S., & Olavarría, C.
Humpback whale, genetics, breeding grounds, South America, breeding stock G
Information on the genetic characterisation of humpback whales (Megaptera novaeangliae) wintering off Ecuador (Breeding Stock G) is presented. Mitochondrial DNA was extracted and sequenced from 230 skin samples collected between 2002 and 2008 to establish the genetic diversity of this population. From 182 usable samples, 41 different haplotypes were found, eight of which were new and unique. Haplotype diversity (h ± SD) was estimated to be 0.922 ± 0.012 and the nucleotide diversity (π ± SD) 0.019 ± 0.009. A comparison with other areas within the Southeast Pacific (Colombia and Magellan Strait) and the Antarctic Peninsula suggested panmixia within Breeding Stock G, even though significant differentiation was found with Magellan Strait (p < 0.0001 in both FST and ΦST). An additional analysis with the exact test of population differentiation showed significant differences in haplotype frequencies between breeding areas in Ecuador and southern Colombia (p < 0.01), suggesting some level of stratification at breeding grounds as supported by photo-identification studies. The Ecuadorian dataset included haplotypes reported in all three Southern Hemisphere ocean basins indicating recent gene flow within the Southern Hemisphere. The population showed a male-biased sex ratio in adult animals of 2.16:1. Further research and a larger number of samples from breeding areas in the north (Panama and Costa Rica) are required to appropriately assess the extent of structure in this population.
8
2013
La Bioprospección Antártica: indefiniciones e incompatibilidades con el sistema del tratado Antártico
Villamizar-Lamus, F.
Antarctic, jurisdiction, law, biotechnology, borders, scientific research, antarctic biological prospection, Antarctic Treaty, lack of definitions and incompatibilities
Pese a que las partes de la Reunión Consultiva del Tratado Antártico de 2009 consideraron que la bioprospección antártica estaba regulada de forma adecuada por la legislación antártica vigente, el presente artículo demuestra que existen problemas jurídicos respecto de la definición de conceptos fundamentales así como posibles incompatibilidades con principios básicos del Tratado Antártico que aún no están resueltas, de manera que haya claridad jurídica para realizar actividades de bioprospección en la Antártida.
9
2014
Molecular systematics of the deep-sea bamboo corals (Octocorallia: Isididae: Keratoisidinae) from New Zealand with descriptions of two new species of Keratoisis
Dueñas, LF., Alderslade, P., & Sánchez, JA.
Antarctica, Large sub-unit rRNA 16S, Octocoral, Taxonomy, igr4, mtMutS.
Bamboo corals belong to a species rich and abundant group of octocorals that occur throughout the world’s oceans, primarily in the deep-sea. Their study through morphological, ecological and evolutionary approaches has been problematic because of the extreme environments many of them inhabit and therefore the difficulty of obtaining good quality samples. However, new undescribed species have been commonly collected as part of invertebrate by-catch studies from commercial fisheries. In this study we describe two new species of deep-sea bamboo corals from New Zealand waters, including the Ross Sea (Antarctica) using morphological and molecular approaches. For the morphological description we used macro-structural characters such as branching pattern, color and polyp arrangement, along with axis architecture and sclerite shape and arrangement. The new species fit in the subfamily Keratoisidinae and the genus Keratoisis. Keratoisis magnifica n.sp. is characterized by having big, highly armed conical polyps and K. peara n.sp. has long, smooth internodes with an unusual nacreous lustre. Additionally, we amplified three mitochondrial genes (16S, igr4 and mtMutS), and obtained optimal topologies through maximum likelihood and Bayesian approaches. The resulting molecular phylogenies corroborated the status of the new taxa and elucidated their relationships to closely related species. Additionally, we show further genetic evidence that branching pattern, as previously thought, could be an unreliable character not only for Lepidisis/Keratoisis, but also for other genera within the Keratoisidinae.
10
2015
Un modelo hidrodinámico del estrecho de Gerlache (Antártida) para el verano del hemisferio sur
Lonin, S.
Estrecho Gerlache, modelo hidrodinámico, témpanos de hielo.
La Primera Expedición Científca de Colombia en la Antártida fue realizada durante el verano del hemisferio sur (enero-febrero de 2015) en el área del estrecho de Gerlache, ubicado en la península Antártica. La información oceanográfca e hidrográfca recolectada durante el crucero permitió implementar un modelo hidrodinámico bajo las condiciones de deshielo con el fn de estudiar los procesos hidrofísicos en el área de estudio con posterior aplicación del modelo a las predicciones del tiempo y el movimiento de los témpanos de hielo. Se formula el modelo hidrodinámico, haciendo énfasis en la descripción matemática de una compleja morfología, con presencia de sistemas de fordos, islas y pasillos angostos. Se analizó el régimen de la marea astronómica, siendo de mayor importancia en la dinámica del estrecho en comparación con las corrientes termohalinas y la deriva de viento para este período del año.
11
2015
Avistamiento de Hielos sobre el Mar en la Bahía de Fildes y el Estrecho de Gerlache durante el Verano Austral 2015
Trujillo, J., Ramírez Cárdenas, J., Vargas, M., Adames Prada, R., & Murillo Gómez, N.
Hielo-Marino, Carta-de-hielos, Verano-Austral
Durante la Primera Expedición Científica de Colombia a la Antártica, desde el buque ARC “20 de Julio” y desde el helicóptero ARC 255, se tomaron registros fotográficos de los hielos avistados sobre el mar. Los hielos fotografiados se identificaron y clasificaron usando la terminología de hielos avalada por la Organización Marítima Mundial (OMM), la Carta de Hielos Antárticos del Servicio Hidrológico y Oceanográfico de la Armada de Chile (SHOA) y el Manual de hielo del Servicio de Hielo Canadiense (MANICE por sus siglas en inglés de Manual of Ice). Se corrobora el comportamiento de la dinámica de deshielo propia del verano austral en la Bahía de Fildes y el Estrecho de Gerlache.
12
2015
Characterization of the Antarctic sea urchin (Sterechinus neumayeri) transcriptome and mitogenome: a molecular resource for phylogenetics, ecophysiology and global change biology
This is the first de novo transcriptome and complete mitochondrial genome of an Antarctic sea urchin species sequenced to date. Sterechinus neumayeri is an Antarctic sea urchin and a model species for ecology, development, physiology and global change biology. To identify transcripts important to ocean acidification (OA) and thermal stress, this transcriptome was created pooling, and 13 larval samples representing developmental stages on day 11 (late gastrula), 19 (early pluteus) and 30 (mid pluteus) maintained at three CO2 levels (421, 652, and 1071 μatm) as well as four additional heat-shocked samples. The normalized cDNA pool was sequenced using emulsion PCR (pyrosequencing) resulting in 1.34M reads with an average read length of 492 base pairs. 40 994 isotigs were identified, averaging 1188 bp with a median coverage of 11×. Additional primer design and gap sequencing were required to complete the mitochondrial genome. The mitogenome of S. neumayeri is a circular DNA molecule with a length of 15 684 bp that contains all 37 genes normally found in metazoans. We detail the main features of the transcriptome and the mitogenome architecture and investigate the phylogenetic relationships of S. neumayeri within Echinoidea. In addition, we provide comparative analyses of S. neumayeri with its closest relative, Strongylocentrotus purpuratus, including a list of potential OA gene targets. The resources described here will support a variety of quantitative (genomic, proteomic, multistress and comparative) studies to interrogate physiological responses to OA and other stressors in this important Antarctic calcifier.
13
2015
Colombia: ¿Miembro Consultativo del Tratado Antartico?
Guzmán, D. A
Tratado Antártico, relaciones internacionales
Las relaciones internacionales de Colombia durante el siglo XX, fueron marcadas esencialmente por dos doctrinas, la doctrina réspice polum, que se alineaba de forma casi irreflexiva a la política exterior de los Estados Unidos y la cual hasta los años noventa, estuvo particularmente marcada por la lucha anticomunista; y la doctrina réspice similia2 (Tokatlian, 2000), que trató de acercarse más a los países latinoamericanos. A pesar que bajo estas dos doctrinas Colombia participó en diferentes escenarios internacionales y suscribió varios tipos de tratados mundiales y regionales, su protagonismo fue escaso, debido en gran parte a la ausencia de intereses nacionales permanentes que guiaran los objetivos de una política exterior consistente. Una de las participaciones internacionales de Colombia, en las cuales hasta hace pocos años no ejerció ninguna acción efectiva, es en el Tratado Antártico (TA).
14
2015
Distinct composition signatures of archaeal and bacterial phylotypes in the Wanda Glacier forefield, Antarctic Peninsula
Several studies have shown that microbial communities in Antarctic environments are highly diverse. However, considering that the Antarctic Peninsula is among the regions with the fastest warming rates, and that regional climate change has been linked to an increase in the mean rate of glacier retreat, the microbial diversity in Antarctic soil is still poorly understood. In this study, we analysed more than 40 000 sequences of the V5-V6 hypervariable region of the 16S rRNA gene obtained by 454 pyrosequencing from four soil samples from the Wanda Glacier forefield, King George Island, Antarctic Peninsula. Phylotype diversity and richness were surprisingly high, and taxonomic assignment of sequences revealed that communities are dominated by Proteobacteria, Bacteroidetes and Euryarchaeota, with a high frequency of archaeal and bacterial phylotypes unclassified at the genus level and without cultured representative strains, representing a distinct microbial community signature. Several phylotypes were related to marine microorganisms, indicating the importance of the marine environment as a source of colonizers for this recently deglaciated environment. Finally, dominant phylotypes were related to different microorganisms possessing a large array of metabolic strategies, indicating that early successional communities in Antarctic glacier forefield can be also functionally diverse.
15
2016
Genetic differentiation between humpback whales (Megaptera novaeangliae) from Atlantic and Pacific breeding grounds of South America
Cypriano-Souza, A ., Engel, M. H., Caballero, S., Olavarría, C., Flórez-González, L., Capella, J., Steel, D., Sremba, A., Aguayo, A., Thiele, D., Baker, C. S., Bonatto, S. L.
Megaptera novaeangliae, population genetic structure, microsatellites, mtDNA, migration, individual assignment.
Humpback whales wintering in tropical waters along the Atlantic and Pacific coasts of the South American continent are thought to represent distinct populations or “stocks.” Here we present the first analysis of genetic differentiation and estimates of gene flow between these breeding stocks, based on both mitochondrial DNA (mtDNA) control region sequences (465 bp) and 16 microsatellite loci from samples collected off Brazil (n = 277) and Colombia (n = 148), as well as feeding areas near the western Antarctic Peninsula (n = 86). We found significant differentiation between Brazilian and Colombian breeding grounds at both mtDNA (FST = 0.058) and microsatellite (FST = 0.011) markers and corroborated previous studies showing genetic similarity between humpbacks from Colombia and those from Antarctic Peninsula feeding areas. Estimates of long-term gene flow between Brazil and Colombia were low to moderate, asymmetrical, and mostly mediated by males. Assignment procedures detected some cases of interchange and individuals of admixed ancestry between breeding grounds, indicating limited mixing of individuals between these stocks. Overall, results highlight the differentiation of humpback whale breeding populations with adjacent feeding grounds. This appears to be a remarkable example of fidelity to seasonal habitat in the absence of any contemporary barriers.
16
2016
Expression pattern of heat shock proteins during acute thermal stress in the Antarctic sea urchin, Sterechinus neumayeri
González, K., Gaitán-Espitia, J., Font A., Cárdenas, C., & González-Aravena, M.
Antarctic marine organisms have evolved a variety of physiological, life-history and molecular adaptations that allow them to cope with the extreme conditions in one of the coldest and most temperature-stable marine environments on Earth. The increase in temperature of the Southern Ocean, product of climate change, represents a great challenge for the survival of these organisms. It has been documented that some Antarctic marine invertebrates are not capable of generating a thermal stress response by means of an increase in the synthesis of heat shock proteins, which could be related with their low capacity for acclimatization. In order to understand the role of heat shock proteins as a compensatory response in Antarctic marine species to projected scenarios of increased seawater temperatures, we assessed the expression of the genes Hsp90, Grp78, Hyou1 and Hsc70 in the Antarctic sea urchin Sterechinus neumayeri under three thermal treatments (1 °C, 3 °C and 5 °C), for a period of exposure of 1, 24 and 48 h.
17
2016
The Antarctic Circumpolar Current as a diversification trigger for deep-sea octocorals
Background: Antarctica is surrounded by the Antarctic Circumpolar Current (ACC), the largest and strongest current in the world. Despite its potential importance for shaping biogeographical patterns, the distribution and connectivity of deep-sea populations across the ACC remain poorly understood. In this study we conducted the first assessment of phylogeographical patterns in deep-sea octocorals in the South Pacific and Southern Ocean, specifically a group of closely related bottlebrush octocorals (Primnoidae: Tokoprymno and Thourella), as a test case to study the effect of the ACC on the population structure of brooding species. We assessed the degree to which the ACC constitutes a barrier to gene flow between northern and southern populations and whether the onset of diversification of these corals coincides with the origin of the ACC (Oligocene-Miocene boundary). Results: Based on DNA sequences of two nuclear genes from 80 individuals and a combination of phylogeographic model-testing approaches we found a phylogenetic break corresponding to the spatial occurrence of the ACC. We also found significant genetic structure among our four regional populations. However, we uncovered shared haplotypes among certain population pairs, suggesting long-distance, asymmetrical migration. Our divergence time analyses indicated that the separation of amphi-ACC populations took place during the Middle Miocene around 12.6 million years ago, i.e., after the formation of the ACC. Conclusion: We suggest that the ACC constitutes a semi-permeable barrier to these deep-sea octocorals capable of separating and structuring populations, while allowing short periods of gene flow. The fluctuations in latitudinal positioning of the ACC during the Miocene likely contributed to the diversification of these octocorals. Additionally, we provide evidence that the populations from each of our four sampling regions could actually constitute different species.
18
2016
Phylogenomics and historical biogeography of the monocot order Liliales: out of Australia and through Antarctica
Givnish, T.J., Zuluaga, A., Marques, I., Lam, V.K.Y., Gomez, M.S., Iles, W.J.D., Ames, M., Spalink, D., Moeller, J.R., Briggs, B.G., Lyon, S.P., Stevenson, D.W., Zomlefer, W., Graham, S.W.
We present the first phylogenomic analysis of relationships among all ten families of Liliales, based on 75 plastid genes from 35 species in 29 genera, and 97 additional plastomes stratified across angiosperm lineages. We used a supermatrix approach to extend our analysis to 58 of 64 genera of Liliales and calibrated the resulting phylogeny against 17 fossil dates to produce a new timeline for monocot evolution. Liliales diverged from other monocots 124 Mya and began splitting into separate families 113 Mya. Our data support an Australian origin for Liliales, with close relationships between three pairs of lineages (Corsiaceae/Campynemataceae, Philesiaceae/Ripogonaceae, tribes Alstroemerieae/Luzuriageae) in South America and Australia or New Zealand reflecting teleconnections of these areas via Antarctica. Long-distance dispersal (LDD) across the Pacific and Tasman Sea led to re-invasion of New Zealand by two lineages (Luzuriaga, Ripogonum); LDD allowed Campynemanthe to colonize New Caledonia after its submergence until 37 Mya. LDD permitted Colchicaceae to invade East Asia and Africa from Australia, and re-invade Africa from Australia. Periodic desert greening permitted Gloriosa and Iphigenia to colonize Southeast Asia overland from Africa, and Androcymbium–Colchicum to invade the Mediterranean from South Africa. Melanthiaceae and Liliaceae crossed the Bering land-bridge several times from the Miocene to the Pleistocene.
19
2016
Orchid historical biogeography, diversification, Antarctica and the paradox of orchid dispersal
Givnish, T.J., Spalink, D., Ames, M., Lyon, S.P., Hunter, S.J., Zuluaga, A., Doucette, A., Caro, G.G., McDaniel, J., Clements, M.A., Arroyo, M.T.K., Endara, L., Kriebel, R., Williams, N.H., Cameron, K.M.
Asparagales, Bi SSE, BioGeo BEARS, long-distance dispersal, Neotropics, Southeast Asia
Aim: Orchidaceae is the most species-rich angiosperm family and has one of the broadest distributions. Until now, the lack of a well-resolved phylogeny has prevented analyses of orchid historical biogeography. In this study, we use such a phylogeny to estimate the geographical spread of orchids, evaluate the importance of different regions in their diversification and assess the role of long-distance dispersal (LDD) in generating orchid diversity. Location: Global. Methods: Analyses use a phylogeny including species representing all five orchid subfamilies and almost all tribes and subtribes, calibrated against 17 angiosperm fossils. We estimated historical biogeography and assessed the importance of different regions for rates of speciation, extinction and net species diversification. We evaluated the impact of particular LDD events on orchid diversity by asking how many species evolved in the new range subsequent to those events. Results: Orchids appear to have arisen in Australia 112 Ma (95% higher probability distribution: 102.0–120.0 Ma), then spread to the Neotropics via Antarctica by 90 Ma (HPD: 79.7–99.5 Ma), when all three continents were in close contact and apostasioids split from the ancestor of all other orchids. Ancestors of vanilloids, cypripedioids and orchidoids+epidendroids appear to have originated in the Neotropics 84–64 Ma. Repeated long- and short-distance dispersal occurred through orchid history: stochastic mapping identified a mean total of 74 LDD events or 0.8 Ma−1. Across orchid history, Southeast Asia was the most important source and maximally accelerated net diversification; across epidendroids, the Neotropics maximally accelerated diversification. Main conclusions: Our analysis provides the first biogeographical history of the orchids, implicating Australia, the Neotropics and Antarctica in their origin. LDD and life in the Neotropics – especially the Andes – had profound effects on their spread and diversification; > 97% of all orchid species are restricted to individual continents.
20
2017
Efectos del ejercicio aeróbico en la composición corporal, resistencia cardiovascular, ciclo circadiano, síndrome T3 Polar en la primera misión de Colombia a la Antártida
En el verano austral 2014-2015 se desarrolló la Primera Expedición de Colombia a la Antártida. Con el propósito de ser país consultivo en el Sistema del Tratado Antártico, la Fuerza Aérea Colombiana se vinculó con un proyecto en ciencias de la salud que pretendía determinar los cambios fisiológicos cardiorrespiratorios, la composición corporal, el síndrome T3 Polar y la calidad del sueño, que se presentan en la aclimatación aguda al frío extremo, en un grupo de expedicionarios de la Antártida, con ejercicio aeróbico durante cuatro semanas de entrenamiento. Se valoraron, en Colombia y en la Antártida, 36 sujetos que aleatoriamente se dividieron en dos grupos; uno realizó ejercicio y otro se mantuvo sedentario. A los participantes se les aplico el índice clínico de Zulewsky, la escala de Epworth, el cuestionario de Pittsburg, consumo máximo de oxígeno y composición corporal. De los 36 sujetos, el 80% son hombres y solo el 20% son mujeres, todos en un promedio de edad de 33.5 años. Los que realizaron ejercicio disminuyeron 4% el IMC, disminuyeron 30% la probabilidad de padecer hipotiroidismo, el 48% mejoraron la calidad de sueño, el 51% disminuyeron la probabilidad de somnolencia diurna y aumentaron el 7% el consumo máximo de oxígeno. El grupo control de sedentarios aumentó 10 % de grasa y disminuyó 10 % su condición cardiovascular. Lo anterior muestra que el ejercicio es un mecanismo protector en la exposición a temperaturas extremas y disminuye la probabilidad de desarrollar patologías metabólicas y cardiovasculares. El sedentarismo, más el frío extremo, deteriora rápidamente las funciones, dando lugar a enfermedades de cualquier tipo.
21
2017
Colombia En El Continente Blanco [Colombia in the White Continent]
Espinel-Bermúdez, J.
Antártida, vinculación, miembro consultivo y política
Se pretende mostrar la importancia que tiene la Antártica para Colombia. En principio, se evidencia la repercusión geoestratégica, científica y económica de este continente, así como la conexión existente entre este lugar y el resto del Planeta; con base en ello es preciso dar conocer la trascendencia del Sistema de Tratado Antártico y el estatus de vinculación de Colombia a esta organización. El alcance que ha tenido la Política Nacional de los Océanos (en adelante PNOEC) para el país al crear y mantener el Programa Antártico Colombiano es relevante y cuyo objetivo primario es llegar a ser miembro consultivo del Tratado, siendo necesario a la vez considerar el papel que juega la Armada Nacional en la PNOEC y la invaluable oportunidad que brinda el Continente Blanco en beneficio de la Nación.
22
2017
COLOMBIA Y ANTÁRTICA: Enlazadas por el mar y su biodiversidad
Fonseca González, I., & Londoño-Mesa, M.
23
2017
Mercury concentrations in wild humpback whales (Megaptera novaeangliae) sampled in the Colombian Pacific and in Antarctic Peninsula
Angel-Romero, P., Barragán-Barrera, D., Botero-Acosta, N., Riet-Sapriza, F., Caballero, S., & Luna-Acosta, A.
"Total
Mercury, Humpback
24
2017
Revisiting the andean tropical glacier behavior during the Antarctic cold reversal
The sensitivity of tropical glaciers to paleoclimatic conditions that prevailed during the Antarctic cold reversal (ACR, ca. 14.5-12.9 ka) has been the subject of a wide debate. In 2014 a paper suggested that tropical glaciers responded very sensitively to the changing climate during the ACR (Jomelli et al., 2014). In this study, we reexamine the conclusions from this study by recalculating previous chronologies based on 226 10Be and 14 3He ages respectively, and using the most up-to date production rates for these cosmogenic nuclides in the Tropical Andes. 53 moraines from 25 glaciers were selected from the previous analysis provided by Jomelli et al. (2014) located in Colombia, Peru and Bolivia. We then focused on two distinct calculations. First we considered the oldest moraine and its uncertainty for every glacier representing the preserved evidence of the maximum glacier extents during the last deglaciation period, and binned the results into 5 distinct periods encompassing the Antarctic cold reversal and Younger Dryas (YD) chronozones: pre-ACR, ACR, ACR-YD, YD and post-YD respectively. Results revealed a predominance of pre-ACR and ACR ages, accounting for 60% of the glaciers. Second we counted the number of moraines per glacier according to the different groups. 21 moraines (40%) of the selected glaciers belong to the pre-ACR-ACR chronozones while 3 moraines only (5%) were dated to the YD and YD-Holocene groups. The rest was assigned to the ACR-YD. These results suggest that moraine records are a very good proxy to document the ACR signal in the Tropical Andes.
25
2017
Climate change effects on Antarctic benthos: a spatially explicit model approach
Torre L., Tabares P.C.C., Momo F., Meyer J.F.C.A., Sahade R.
Resumen: The Antarctic Peninsula is one of the regions on the Earth with the clearest evidence of recent and fast air warming. This air temperature rise has caused massive glacier retreat leading to an increased influx of glacier meltwater which entails hydrological changes in coastal waters, increasing sediment input and ice-scouring impact regime. It has been hypothesized that an increase of sediment load due to glacier retreat resulted in a remarkable benthic community shift in Potter Cove, a small inlet of the South Shetland Islands. In order to test this hypothesis, we developed an explicit spatial model to explore the link between sedimentation and ice-scouring increase upon four of the most conspicuous benthic species. This is a valuable novel approach since disturbances are strongly dependent of the space. The model takes into account sediment and population dynamics with Lotka-Volterra competition, a sediment-dependent mortality term and a randomized ice-scouring biomass removal. With the developed algorithm, and using a MATLAB environment, numerical simulations for scenarios with different sedimentation and ice-impact rates were undertaken in order to evaluate the effect of this phenomenon on biological dynamics. Comparing simulation results with biological data, the model not only recreates the spatial community distribution pattern but also seems to be able to recreate the shifts in abundance under sedimentation enhancement, pointing out its importance as a structuring factor of polar benthic communities. Considering the challenges of Antarctic field work, this model represents a powerful tool for assessing, understanding, and predicting the effects of climate change on threatened Antarctic coastal ecosystems.
26
2018
An initial approximation to the meteo-marine conditions of south bay (Doumer island) and comparison of the meteorological behavior between Doumer and Anvers islands, Antarctica (austral summer 2016-2017)
Villegas, N., Málikov, I., & Cárdenas, C.
Western Antarctic Peninsula, Palmer Archipelago, meteorology, seawater temperature
In order to contribute to the meteo-marine knowledge of the Western Antarctic Peninsula (WAP), the behavior of some atmospheric characteristics of South Bay is described and meteorological differences were identified in two islands of the Palmer Archipelago (south of the Gerlache Strait). The data was obtained during the III Colombian Antarctic Expedition in the Austral summer 2016-2017. The series of air temperature, relative humidity, dew point temperature, wind direction and wind speed at Doumer Island were compared with those recorded at Anvers Island and with sea temperature behavior at 10 m depth in South Bay (Doumer Island). It was concluded that although Anvers and Doumer Islands are neighboring, the behavior of meteo-marine variables in the Austral summer 2016-2017 differs.
27
2018
Hielo. Bitácora de una expedicionaria antártica
Posada-Swafford, A.
Desde hace casi quince años una de las principales periodistas científicas colombianas ha realizado expediciones a la Antártida, el enorme continente de hielo que ha sido uno de los territorios más enigmáticos de la geografía del mundo, y que alberga al Polo Sur. Explorado por grandes aventureros como Roald Amundsen y Robert Scott, quienes protagonizaron un reto de dimensiones épicas para ver cuál de los dos llegaba primero al punto más central de una de las antípodas, este territorio es aún una gran incógnita que fascina a científicos y a viajeros. Posada-Swaἀord, con la paciencia de quien recolecta historias y anécdotas, datos útiles y leyendas, centenas de apuntes y objetos (piedras, plumas de pingüino, insignias de expediciones, etcétera), construyó una bitácora única en la que quedan consignadas sus reflexiones sobre el país del hielo que amenaza con desaparecer por el calentamiento global.
28
2018
An overview of Colombia’s Antarctic programme
Sanchez, W.A.
Colombia, navy, Antarctica, Latin America, 20 de Julio
This paper provides an overview of the history and growth of Colombia’s Antarctic programme and how it has rapidly progressed in recent years. The country carried out its first Antarctic expedition with a domestically manufactured vessel during the 2014–2015 austral summer. Annual expeditions have continued since then, and in early 2018 the government announced its intention to acquire a new vessel and establish a seasonal base by 2025 at the latest in a location yet to be determined. This rapid succession of achievements demonstrates Colombia’s seriousness about its Antarctic programme. Nevertheless, a major challenge will be to secure funding for its Antarctic programme, thus 2018 will be a critical year as the country will hold general elections, and it will be imperative for the next administration to consider the programme a priority in order to maintain its momentum. It is important to understand the intention and objectives of non-claimant nations with growing Antarctic programmes and for the international community to harness this interest so that they can carry out meaningful contributions in order to protect Antarctica.
29
2018
Detenerse a respirar en el fin del mundo: Colombia en Antártida
López, N.
Arte, Antártida, conservación, programa antártico colombiano.
El Proyecto Colombiano de Arte en Antártida (PCAA) acerca la Antártida, su importancia y sus problemáticas, a un público general. La meta es consolidar un programa artístico y cultural que haga visible, a nivel nacional e internacional, la participación de Colombia en las misiones que se llevan a cabo en el continente blanco, mientras crea conciencia sobre el inmenso valor que este representa para la vida en el planeta. Se aspira a que en 2035 el pcaa se haya institucionalizado dentro del circuitoartístico de Colombia. En ensayo fotográfico hace un recorrido por intervenciones sutiles: recolectar agua de los hielos que se descongelan, tomar el pulso del corazón antártico, atrapar aire frío y luego repartirlo por el mundo.
30
2018
First record of Juncaceicola as endophytic fungi associated with Deschampsia antarctica Desv.
Andrade, G.A.K., Cañón, E.R.P., Alves, R.P., Schmitz, D., Schünemann, A.L., de Albuquerque, M.P., Putzke, J., Pereira, A.B., Victoria, F.C.
In the current study, we present the molecular characterization of an endophyte fungus associated with the leaves of Deschampsia antarctica Desv. (Poaceae), a monocot species native to Antarctica. The isolate was obtained from 90 leaf fragments from two distinct collection sites, both located on Half Moon Island, South Shetland Islands and Maritime Antarctica. The internal transcribed spacer region (ITS) was sequenced and the endophytic fungus was identified as belonging to the genus Juncaceicola Tennakoon, Camporesi, Phook and K.D. Hyde (99% nucleotide sequence identity). When compared to all fungi of the genus Juncaceicola deposited in data base, our isolate showed greater proximity with Juncaceicola typharum, however, because it presents a low bootstrap value to be considered a new species, we treat it as Juncaceicola cf. typharum. Moreover, the identification of our isolate as belonging to the genus Juncaceicola makes this the first occurrence of a species of this genus to be associated with the leaves of Antarctic plants. This work is considered as a starting point for other studies with fungi of this genus associated with leaves of Deschampsia antarctica, as it presents results from two collection points on a single Antarctic island, suggesting that new sites and new Antarctic islands should be explored.
31
2018
Geographic and temporal patterns of non-lethal attacks on humpback whales by killer whales in the eastern South Pacific and the Antarctic Peninsula
The role and impact of killer whales Orcinus orca as predators of baleen whales has been emphasized by studies of humpback whales Megaptera novaeangliae. In this study, rake marks on the fluke were used as a proxy for predatory attacks in a sample of 2909 adult humpback whales and 133 calves from 5 breeding and 2 feeding locations in the eastern South Pacific and the Antarctic Peninsula. The goal of this study was to evaluate how often, at what age, where, and when humpback whales were more susceptible to attacks. Overall, 11.5% of adults and 19.5% of calves had rake marks on their flukes. Significant differences were found in the prevalence of scars in calves when comparing breeding (9%) vs. feeding areas (34%) (Χ 2 = 10.23, p < 0.01). Multi-year sighting analysis of scar acquisition in 120 adults (82% site fidelity) and 37 calves in the Magellan Strait showed no new marks after the initial sighting for the subsequent 15 yr. This finding indicates that rake marks were most probably acquired when whales were calves, which supports the belief that scar acquisition is a once in a lifetime event. The odds of having rake marks increased with time but with a significantly higher rate in calves (Χ 2 = 5.04, p < 0.05), which suggests an increase in predation pressure over time. Our results support the earlier hypothesis that killer whale attacks occur mostly on calves, near breeding sites, and during the first migration to feeding areas.
32
2018
Distribucion Espacial de la Varibale densidad de los estrechos de Gerlache y Bransfield durante el verano austral entre 1979-2019.
Torres Ramirez F. J
Tratado Antartico, Gerlache, Bransfield, Densidad, Control de Calidad, Verano Austral
Colombia ha realizado expediciones a la Antártica desde el año 2014, con el objetivo de contribuir al conocimiento sobre el continente blanco y materializar los intereses nacionales sobre el mismo. El presente estudio aporta al entendimiento de la dinámica oceanográfica en los estrechos de Gerlache y Bransfield a partir del análisis conjunto de información de temperatura, salinidad y presión recolectada con equipos CTD durante las expediciones antárticas realizadas por Colombia entre los años 2014 y 2019, complementada con información de 40 años obtenida del World Ocean Database. Este análisis permitió a través de un control de calidad previo, calcular y graficar la distribución horizontal de la variable densidad a diferentes profundidades estándar durante el verano austral entre 1979 a 2019, para así entender la distribución de la variable mencionada en el área de estudio. Se analizó el comportamiento de la densidad, demostrando a través de los resultados que, este parámetro se da en razón a las variaciones de la salinidad y no de la temperatura como ocurre en latitudes bajas. A diferencia de estudios previos realizados en la península Antártica para un año particular, en la presente investigación se seleccionó un periodo de 40 años del verano austral (meses de enero, febrero y marzo), con miras a conocer la distribución horizontal de la variable densidad para diferentes profundidades estándar y a determinar las condiciones esperadas, las cuales son un indicador de comportamiento a nivel general en el área de estudio.
33
2019
Effects of an Explosive Polar Cyclone Crossing the Antarctic Marginal Ice Zone
Vichi, M., Eayrs, C., Alberello, A., Bekker, A., Bennetts, L., Holland, D., de Jong, E., Joubert, W., MacHutchon, K., Messori, G, Mojica, J., Onorato, M., Saunders, C., Skatulla, S., & Toffoli, A.
Antarctic sea ice shows a large degree of regional variability, which is partly driven by severe weather events. Here we bring a new perspective on synoptic sea ice changes by presenting the first in situ observations of an explosive extratropical cyclone crossing the winter Antarctic marginal ice zone (MIZ) in the South Atlantic. This is complemented by the analysis of subsequent cyclones and highlights the rapid variations that ice-landing cyclones cause on sea ice: Midlatitude warm oceanic air is advected onto the ice, and storm waves generated close to the ice edge contribute to the maintenance of an unconsolidated surface through which waves propagate far into the ice. MIZ features may thus extend further poleward in the Southern Ocean than currently estimated. A concentration-based MIZ definition is inadequate, since it fails to describe a sea ice configuration which is deeply rearranged by synoptic weather.
34
2019
How are we getting there? The present and future of South America’s Antarctic fleet
Sanchez, W.A.
Polar Vessels, Shipyards, Peru, Chile, Argentina, Brazil, Icebreaker
While South America is geographically close to Antarctica, more so than some countries that claim Antarctic territory, it is nevertheless important to maintain modern and operational platforms, particularly vessels, via which South American states can travel to this region. In recent years, Peru has obtained a new polar vessel, while Chile is domestically manufacturing a new icebreaker and Brazil is looking to purchase a new polar ship. Nevertheless, countries like Argentina and Uruguay, due to limited funds, do not appear to have plans to acquire new polar vessels to replace their current, ageing naval platforms. Certainly, governments can also utilise aircraft to transport personnel and equipment to Antarctica as well as to carry out some scientific tests and search-and-rescue operations. However there are particular advantages to possessing a vessel in the inventory of any country’s Antarctic program, since it can transport heavy equipment, and perform subsurface tests out at sea. Polar vessels also carry smaller craft and a helicopter, which multiplies the ship’s capabilities. This essay aims to discuss the current operational status of South America’s polar platforms, with a specific focus on ships, and what are their future. We will analyse the region’s ships and compare them to other nations that have Antarctic programmes (e.g. Australia, the People’s Republic of China and the United States), in order to have an idea of how South American states are doing in comparison to other programs. As we look at South America’s present and attempt to predict the region’s future in Antarctica, we will discuss issues like cooperation amongst South American Antarctic programs, and the future of regionally manufactured naval platforms for polar use.
35
2019
Zooplankton composition and taxonomic abundance from South Pacific until Antarctic Peninsula 2016-2017
López L.H.M.; Franco-Herrera Andres.
Antarctica, Connectivity, South Pacific, Zooplankton
Mesozooplankton biomass and epipelagic copepod assemblage composition and distribution were studied in the Gerlache Strait from January 17 to 22, 2015, as part of the first Colombian oceanographic expedition to the Antarctic. Mesozooplankton-integrated biomass was generally low (< 5 mgdry weight/m−2) in the outer area of the northern section of the Gerlache Strait (between Crocker Passage and Hughes Bay) although there was a notable increase southward, with the highest value (1.02 g dry weight / m−2) at the entrance of Wilhelmina Bay in the central zone of the Strait. The epipelagic copepod assemblage comprised 17 species belonging to 4 orders and 13 families. The dominant species by number was Oithona similis, followed by O. frigida, Ctenocalanus citer, Drescheriella glacialis, and Calanoides acutus. Aetideus armatus is reported for the first time in the western sector of the Antarctic Peninsula. Differences in the assemblages of copepods between the northern and southern section of the Gerlache Strait were established. Considering the previous results reported about hydrography and phytoplankton composition in Gerlache Strait and our analysis of the copepod assemblage structure, a scenario is suggested in which, at less during January 2015, each section of the Strait exhibited a particular copepod assemblage structure: a northern section was dominated by small-sized copepods while the southern section was dominated by small-sized and large-sized copepods.
37
2020
Beach litter distribution in Admiralty Bay, King George Island, Antarctica
Anfuso, G., Bolívar-Anillo, H., Asensio-Montesinos, F., Portantiolo Manzolli, R., Portz, L., & Villate Daza, D.
In the Antarctic Peninsula, most important activities are touristic visits, from the second half of the 20th Century, and scientific investigation linked to 75 research stations. Beach litter content/abundance was investigated at 17 beaches in Admiralty Bay (King George Island, Antarctica) and the type of plastic material was determined by Raman spectroscopy. An average value of 0.16 items m−1 was observed. Wood items consisted of processed wood fragments representing 47.27% of the total. Foam represented 21%, hard plastic pieces 9.68% (consisting of polyvinyl chloride or high density polyethylene), metal 3.37%, rubber fragments 2.81%, foamed plastic pieces 2.66% (composed by polystyrene), the rest of categories representing less than 2% of the total. Wood debris and metal are essentially remnant objects of ancient whaling activities and research expeditions, polyurethane and expanded polystyrene materials have different origins and hard plastic, rubber, paper/cardboard and paint fragments seem mostly linked to present research activities.
38
2020
Colombia in the Antarctica: Approaches to a scientific/social investigation. A call to the academy/state/society
Lopera-Ramírez, L.
Antártida, proyecto de país, enfoque diferencial
La Antártida, para muchos desconocida, para otros épica, y para las grandes potencias del globo un lugar de posicionamiento geoestratégico sin precedentes, merece la atención no solo del andamiaje estatal como tal, sino de una triada donde a este se anejan la academia y la sociedad desde su expresión visionaria/participativa que permite entregar el valor necesario a un “proyecto país” con enfoque diferencial, direccionado a los intereses nacionales, desde el entendido que estos trascienden más allá de las fronteras, donde las relaciones internacionales y la política exterior de un estado permiten la gestión. Con el fin de adentrarnos en el objeto de estudio, es preciso contextualizar algunos aspectos que permitirán un recorrido entre la relevancia y la fastuosa historia del Continente Blanco. En principio, se hará referencia a la importancia estratégica, sus características y lo que sígnica para el hemisferio en conjunto con el majestuoso Océano Antártico que lo rodea.
39
2020
Diversity and Functioning of Antarctic Seaweed Microbiomes
Gaitán-Espitia, J., & Schmid, M.
Antarctic macroalgae are important primary producers and habitat-forming species that play fundamental roles in Antarctic coastal habitats and sustain important communities of benthic organisms, including a not well-known microbiota. Anthropogenic pressures, e.g., increasing ocean temperatures and extreme events, have threatened the ecological integrity of several seaweed species and also can modify the range shifts (e.g., introduction of Durvillaea antarctica in King George Island), cause local extinctions, and alter the structure of these associations in their natural habitats. However, understanding and prediction of the responses of seaweeds to changing environment and rapid anthropogenic-driven change cannot be done without considering the associated microbiome. These complex microbial communities are intricately involved in the host health, defense, growth, and development of seaweeds, thus with far-reaching implications for the ecology of the whole coastal ecosystem. For most Antarctic seaweeds, the microbiome comprises a stable core as well as microbes whose presence depends on local conditions and transient microbial associates that are responsive to biotic and abiotic processes across spatial and temporal scales. In this chapter, we will explore the ecological and genetic diversity of microbiomes in Antarctic seaweeds and their functional connections.
40
2020
Estructura y distribución de la comunidad microfitoplanctónica a lo largo del estrecho de Gerlache durante el verano austral 2018-2019
De La Hoz Barrientos, L., Cañón Páez, M., & Sánchez, D.
microfitoplancton, estructura, Antártica, estrecho de Gerlache
En el presente estudio se describe la estructura de la comunidad fitoplanctónica y su distribución en el estrecho de Gerlache durante el verano austral 2018-2019. Se realizaron arrastres verticales de 200 m a la superficie a través de una red bongo equipada con flujómetro. Las muestras se fijaron en lugol básico, en una relación 100:1. Muestras adicionales para el análisis de nutrientes y clorofila-a se tomaron a través de una roseta oceanográfica. Mediante un análisis de funciones empíricas ortogonales estandarizadas el estrecho de Gerlache fue regionalizado en cuatro regiones, usando los datos de riqueza y químicos. De las regiones identificadas se ubicaron dos en el norte, una en el centro y otra en el sur. En términos de riqueza se identificaron 40 taxones representados por 28 diatomeas, once dinoflagelados y un silicoflagelado. La mayor riqueza y abundancia se encontró en la región central, siendo las diatomeas el grupo dominante en todas las estaciones. Las especies Corethron criophilum y Porosira glacialis representaron el mayor aporte a la comunidad. Los dinoflagelados formaron el segundo grupo más distintivo en el área de estudio, representado por las especies Protoperidinium pyrum y Prorocentrum minimun. Por otra parte, los silicoflagelados con la especie Dictyocha sp. fueron el grupo con menor representatividad en el área; sin embargo, su mayor abundancia se observó en la región norte. Con base en investigaciones realizadas por otros autores en años anteriores para el mismo periodo climático se evidenciaron diferencias en la estructura de la comunidad, con dominancia de las diatomeas sobre los demás grupos identificados; dichos cambios pueden obedecer a las técnicas analíticas empleadas y a la variabilidad interanual.
41
2020
From Space to Earth: physical and biological impacts of glacier dynamics in the marine system by means of Remote Sensing at Almirantazgo Bay, Antarctica
Cárdenas, C., Casassa, G., Aguilar, X., Mojica, D., Johnson, E., & Brondi, F.
To determine the biological and physical mechanisms between Lange glacier and its pro-glacier marine system located in Almirantazgo bay, King George Island, Antarctica, specific variables were determined through remote sensing approaches shown in this work. These preliminary results will allow relating the dynamics of both systems, the glacier, and the marine ecosystem. The information for the estimation of surface flux velocity of the glacier was derived through Radar satellite images (Sentinel-1) by means of offset tracking, the bathymetry was derived from a Multi-beam Echo Sounder, and the Digital Elevation Modell was obtained by means of a Remotely Piloted Aircraft; Finally, the biological parameters were derived from MODIS and OLCI images for the analysis of satellite data to have a first insight to the characteristics of the marine system. This information will help to build the first frame needed to study through remote sensing approaches, the mechanisms that govern the interface among “Lang Glacier” and the “Almirantazgo Bay” at King George Island, Antarctica.
42
2020
Installing a prototype wind turbine to produce energy in Antarctica to allow a permanent Colombian scientific base to be established
Lozano-Jiménez, C.
Wind energy, renewable energy, Marambio Station, Seymour Island, Colombia Antarctic Program
This study was performed to support an expeditionary team of Colombian scientists seeking to promote and undertake research in various scientific fields in Antarctica. The work was part of the Colombian Antarctic program, which comprises various projects intended to lead to a permanent Colombian scientific base being established in the Antarctic. The first step involved installing a Colombian-made wind turbine to produce electricity at a permanent base. The aeolian turbine was designed to provide sufficient electricity to illuminate and heat a small base. The turbine was constructed using readily accessible materials but taking the Madrid Protocol environmental regulations into consideration. The project was performed at the Argentinian Antarctic Marambio Station on Seymour Island, off the Antarctic Peninsula. An initial field study performed in 2015 was the first of three phases of the project. In the initial phase, local meteorological data were gathered to support development of a prototype turbine and to allow a design to be selected that was robust enough for the extreme environmental conditions. The wind turbine was then constructed in Colombia. The second phase involved transporting the turbine to Antarctica and installing it at the Marambio Station in 2018. Finally, the physical conditions of structural and electronic components of the turbine were carefully inspected at the beginning of 2020 (after the turbine had operated continually for ~2 years) to allow repairs to be made and any necessary re-engineering to be performed.
43
2020
Projected shifts in the foraging habitat of crabeater seals along the Antarctic Peninsula
Hückstädt, L., Piñones, A., Palacios, D., McDonald, B., Dinniman, M., Hofmann, E., BurnsM J., Crocker, D., & Costa, D.
Crabeater seals exhibit extreme dietary specialization, feeding almost exclusively on Antarctic krill. This specialization has inextricably linked habitat use, life history and evolution of this pinniped species to the distribution of its prey. Therefore, the foraging habitat of crabeater seals can be used to infer the distribution of Antarctic krill. Here, we combined seal movements and diving behaviour with environmental variables to build a foraging habitat model for crabeater seals for the rapidly changing western Antarctic Peninsula (WAP). Our projections show that future crabeater seal foraging habitat and, by inference, krill distribution will expand towards offshore waters and the southern WAP in response to changes in circulation, water temperature and sea ice distribution. Antarctic krill biomass is projected to be negatively affected by the environmental changes, which are anticipated to manifest as a decrease in krill densities in coastal waters, with impacts on the land-/ice-based krill predator community, particularly in the northern WAP.
44
2020
Stereo-Photogrammetric Measurement Of Spatio-Temporal Velocity Fields At Lange Glacier, King George Island
Ellen Schwalbe, Robert Koschitzki, Erling Johnson, Diego Fernando Mojica Moncada, Benjamin Schröter, Carlos Cardenas, Gino Casassa & Hans-Gerd Maas
A network consisting of six cameras was set up on both sides of Lange Glacier on King George Island, Antarctica, for a period of two years to monitor changes in the glacier's motion behaviour. The cameras were observing spatio-temporal glacier surface velocity vector fields as well as the position of the glacier front. Velocity field information was obtained from image sequences by applying subpixel accuracy photogrammetric image sequence analysis techniques. Georeferencing in a superordinate coordinate system was performed via integrated photogrammetric-geodetic network adjustment. As a result, velocity fields were determined with maximum glacier surface velocities in the order of 1.5 meter per day. The results of terrestrial camera image sequence processing can be used as validation and calibration reference for satellite image based glacier velocity dynamics calculations. Moreover, the very high temporal resolution of the image sequences taken at 20 minute time intervals can also be used to analyse highly dynamic processes.
45
2020
Latitudinal gradients of haemosporidian parasites: Prevalence, diversity and drivers of infection in the Thorn-tailed Rayadito (Aphrastura spinicauda)
Cuevas, E., Vianna, J.A., Botero-Delgadillo, E., Doussang, D., González-Acuña, D., Barroso, O., Rozzi, R., Vásquez, R.A., Quirici, V.
Haemoproteus, Haemosporidian parasites, Latitudinal gradient Leucocytozoon, Plasmodium, South American temperate forests
Latitudinal gradients are well-suited systems that may be helpful explaining distribution of haemosporidian parasites and host susceptibility. We studied the prevalence, diversity and drivers of haemosporidian parasites (Leucocytozoon, Plasmodium and Haemoproteus) along a latitudinal gradient (30°–56° S), that encompass the total distribution (~3,000 km) of the Thorn-tailed Rayadito (Aphrastura spinicauda) in the South American temperate forests from Chile. We analyzed 516 individuals from 18 localities between 2010 and 2017 and observed an overall prevalence of 28.3% for haemosporidian parasites. Leucocytozoon was the most prevalent parasite (25.8%). We recorded 19 distinct lineages (13 for Leucocytozoon, five for Plasmodium, and one for Haemoproteus). Differences in haemosporidian prevalence and diversity by genus and type of habitat were observed in the latitudinal gradient. Further, we support the existence of a latitudinal associate distribution of Leucocytozoids in South America, where prevalence and diversity increase toward higher latitudes. Distribution of Leucocytozoon was associated with sub-antarctic habitat (higher latitude) and explained by cold temperature and high precipitation. On the other hand, we lacked to find a latitudinal associate pattern for Plasmodium and Haemoproteus, however low prevalence and high diversity were recorded in areas considered as a hotspot of biodiversity in Central Chile. Our findings confirmed the importance of habitat and climatic variables explaining prevalence, diversity and distribution of haemosporidian parasites in a huge latitudinal gradient, belonging the distribution of the Thorn-tailed Rayadito in the world's southernmost forests ecosystems.
46
2020
Humpback whales extend their stay in a breeding ground in the Tropical Eastern Pacific
breeding site, Cetacea, Colombian Pacific, conservation, environmental changes, G-stock, Gorgona National Park, Megaptera novaeangliae, migration time
During the austral winter, G-stock humpback whales, Megaptera novaeangliae, migrate to the Tropical Eastern Pacific to breed. To analyse if the whale migration times have changed over time, we analysed 31 years (1988-2018) of arrival and departure times to Gorgona National Park, Colombia, an important breeding site. During this period, whales have significantly changed their arrival time, coming now earlier, but their departure time has not changed significantly. Hence, humpback whales now stay 1 month longer than 31 years ago. Humpbacks arrived in Gorgona at the earliest during the beginning of May and stayed at the most until late December. The change observed in the arrival time to breeding grounds could be related to ice sheet mass changes in autumn in Antarctica and increase in population size over the past decades but we were unable to determine which factor is more important in explaining the observed trend. Management decisions in Colombia need to account for a longer stay, specifically restricting anthropogenic activities from 1May to 31December. We urge other researchers to review their data, in case this shift is evident in other regions and management plans need to be updated.
47
2020
Hydrographic conditions during two austral summer situations (2015 and 2017) in the Gerlache and Bismarck straits, northern Antarctic Peninsula
Antarctic peninsula, OMP analysis, Water masses, θ-S diagram
Hydrography in the Gerlache and Bismarck straits is described based on data collected in Januaries of 2015 and 2017, during austral summer. These straits are in the northern Antarctic Peninsula (NAP) continental shelf. In the study area, temperature in the surface mixed layer during January 2017 was warmer than recorded in other years, contemporaneous with an extreme decrease in Antarctic sea ice extent at the end of 2016. This was probably caused by warm water advected from the north into Gerlache Strait, a consequence of northeasterly surface winds over the NAP, forced by a Southern Annular Mode (SAM) negative phase. Optimum multiparameter analysis indicated that relatively warm, salty and low-oxygenated modified Circumpolar Deep Water (mCDW) intrudes over the NAP continental shelf and dominates the Bismarck Strait, where it enters the Gerlache Strait, especially through its southern extremity. The mCDW mixes with relatively cold, fresh and recently ventilated modified High Salinity Shelf Water (mHSSW), producing temporal variations in water proportions. HSSW forms in the Weddell Sea and is advected southward along the deep basins of the Bransfield Strait, entering as bottom water into Gerlache Strait via its northern limit. There were two fronts in Gerlache Strait during both summers. First was a surface thermal front in the mixed layer represented by the 1 °C isotherm (~64.5°S), which separated colder waters toward Bismarck Strait. Second was a sub-pycnocline front, represented by the 0.4 °C and 220 μmol kg−1 dissolved oxygen contours below ~100 dbar, which separated mCDW toward Bismarck Strait from mHSSW on the northern side of the strait. This frontal position varies as a consequence of temporal variations in source water fractions. Moreover, changes in Ekman transport, forced by enhanced westerly winds associated with a SAM positive phase, appeared responsible for a major fraction of mCDW in Gerlache Strait during 2015 relative to 2017. The spatiotemporal variability of source water mixing in the water column structure of the Gerlache Strait might have implications for local biological and chemical cycles, and for regional climate feedbacks, because warm mCDW accelerates glacier retreat in the western Antarctic Peninsula.
48
2021
Interannual Climate Variability in theWest Antarctic Peninsula under Austral Summer Conditions
Santamaría-del-Ángel, E., Cañon-Páez, M., Sebastiá-Frasquet, M., González-Silveira, A., Gutierrez, A., Aguilar-Maldonado, J., López-Calderón, J., Camacho-Ibar, V, Franco-Herrera, F., & Castillo-Ramírez, A.
climate variability, West Antarctic Peninsula (WAP), SST, multi-sensor LAC imagery, five-year warm cycle, Southern Annular Mode (SAM)/Antarctic Oscillation (AAO), Southern Oscillation Index (SOI), WAP marine ecoregions, Group on Earth Observations (GEO).
This study aimed to describe the interannual climate variability in the West Antarctic Peninsula (WAP) under austral summer conditions. Time series of January sea-surface temperature (SST) at 1 km spatial resolution from satellite-based multi-sensor data from Moderate Resolution Imaging Spectrometer (MODIS) Terra, MODIS Aqua, and Visible Infrared Imager Radiometer Suite (VIIRS) were compiled between 2001 and 2020 at localities near the Gerlache Strait and the Carlini, Palmer, and Rothera research stations. The results revealed a well-marked spatial-temporal variability in SST at the WAP, with a one-year warm episode followed by a five-year cold episode. Warm waters (SST > 0 °C) reach the coast during warm episodes but remain far from the shore during cold episodes. This behavior of warm waters may be related to the regional variability of the Antarctic Circumpolar Current, particularly when the South Polar Front (carrying warm waters) reaches the WAP coast. The WAP can be divided into two zones representing two distinct ecoregions: the northern zone (including the Carlini and Gerlache stations) corresponds to the South Shetland Islands ecoregion, and the southern zone (including the Palmer and Rothera stations) corresponds to the Antarctic Peninsula ecoregion. The Gerlache Strait is likely situated on the border between the two ecoregions but under a greater influence of the northern zone. Our data showed that the Southern Annular Mode (SAM) is the primary driver of SST variability, while the El Niño Southern Oscillation (ENSO) plays a secondary role. However, further studies are needed to better understand regional climate variability in the WAP and its relation with SAM and ENSO; such studies should use an index that adequately describes the ENSO in these latitudes and addresses the limitations of the databases used for this purpose. Multi-sensor data are useful in describing the complex climate variability resulting from the combination of local and regional processes that elicit different responses across the WAP. It is also essential to continue improving SST approximations at high latitudes.
49
2021
Site Selection of the Colombian Antarctic Research Station Based on Fuzzy-Topsis Algorithm
Jairo R. Coronado-Hernández, Wilson A. Rios-Angulo, Camilo Segovia, Diana Urrego-Niño & Alfonso R. Romero-Conrado
Site selection, Fuzzy TOPSIS, Antarctic station.
By 2025 the Republic of Colombia aims to be an advisory member of the Antarctic Treaty System (ATS) and the installation of a scientific station is necessary to upscale the scientific capabilities. The aim of this paper is showing the results of the implementation of a Fuzzy TOPSIS algorithm for site selection of the Colombian Antarctic Scientific Station. A three-phase methodology was proposed, and the obtained results allowed to identify the optimum location for the station, considering key success factors and regulatory constraints.
50
2021
Contributions to the knowledge of macroalgae of the Gerlache Strait - Antarctica
Rincón Díaz, N., Macaya, E., & Guzmán Henao, S.
Macroalgas, Antártica, Estrecho de Gerlache, Rhodophyta, Ochrophyta, Cambio climático.
Esta investigación es un aporte al conocimiento de algunas especies de macroalgas marinas que fueron recolectadas durante las expediciones científicas “Almirante Padilla” (2016-2017) y “Almirante Campos” (2018-2019), en las que participó el Instituto de Investigaciones Marinas y Costeras-Invemar con el proyecto: Biodiversidad y Condiciones Oceanográficas del Estrecho de Gerlache “Biogerlache-Antártica”. Se realizaron recolectas usando draga tipo Shipek y videos subacuáticos con un ROV (Remote Operated Vehicle). Se identificaron seis especies, cuatro Rhodophyta y dos Ochrophyta-Phaeophyceae. Se incluye información sobre la profundidad y zonación donde las macroalgas fueron halladas, y su relación con registros previos para el área de estudio.
