Darwin's Early Notes on Coral Reef Formation

1984 ◽  
Vol 3 (2) ◽  
pp. 160-163 ◽  
Author(s):  
Frederick Burkhardt
Keyword(s):  
Coral Reef ◽  
South America ◽  
Point Of View ◽  
South American ◽  
American Continent ◽  
The Pacific ◽  
The Pacific Ocean ◽  
South American Continent ◽  
Reef Formation ◽  
Water Coral

Darwin's letters and some rough notes found in his field notebooks of 1835 confirm the statement in his Autobiography that he had formulated his theory of coral reef formation before the Beagle left South America and before he had seen a coral reef. His geological observations having convinced him of the elevation of the South American continent, Darwin predicted that evidence of a compensatory gradual subsidence of the Pacific Ocean floor would be found in the existence of shallow-water coral genera in the Pacific reef formations. The first draft of the theory was written on board the Beagle shortly after seeing the reefs of Moorea in November 1835. After visiting the Cocos (Keeling) Islands he wrote a summary of his view in a letter of April 1838, in which he expressed his conviction that he had found an explanation which would "put some of the facts in a more simple and connected point of view, than that in which they have hitherto been considered".

scholarly journals Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world

2019 ◽  
Author(s):  
Jonas A. Arnemann ◽  
Stephen H. Roxburgh ◽  
Tom Walsh ◽  
Jerson V.C. Guedes ◽  
Karl H.J. Gordon ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Gene Flow ◽  
South America ◽  
New World ◽  
Flow Patterns ◽  
South American ◽  
Southern Brazil ◽  
American Continent ◽  
Central Brazil ◽  
South American Continent

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.

scholarly journals Multiple incursion pathways for Helicoverpa armigera in Brazil show its genetic diversity spreading in a connected world

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jonas Andre Arnemann ◽  
Stephen Roxburgh ◽  
Tom Walsh ◽  
Jerson Guedes ◽  
Karl Gordon ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Gene Flow ◽  
South America ◽  
New World ◽  
Flow Patterns ◽  
South American ◽  
Southern Brazil ◽  
American Continent ◽  
Central Brazil ◽  
South American Continent

AbstractThe Old World cotton bollworm Helicoverpa armigera was first detected in Brazil with subsequent reports from Paraguay, Argentina, Bolivia, and Uruguay. This pattern suggests that the H. armigera spread across the South American continent following incursions into northern/central Brazil, however, this hypothesis has not been tested. Here we compare northern and central Brazilian H. armigera mtDNA COI haplotypes with those from southern Brazil, Uruguay, Argentina, and Paraguay. We infer spatial genetic and gene flow patterns of this dispersive pest in the agricultural landscape of South America. We show that the spatial distribution of H. armigera mtDNA haplotypes and its inferred gene flow patterns in the southwestern region of South America exhibited signatures inconsistent with a single incursion hypothesis. Simulations on spatial distribution patterns show that the detection of rare and/or the absence of dominant mtDNA haplotypes in southern H. armigera populations are inconsistent with genetic signatures observed in northern and central Brazil. Incursions of H. armigera into the New World are therefore likely to have involved independent events in northern/central Brazil, and southern Brazil/Uruguay-Argentina-Paraguay. This study demonstrates the significant biosecurity challenges facing the South American continent, and highlights alternate pathways for introductions of alien species into the New World.

A BOUGUER GRAVITY ANOMALY MAP OF SOUTH AMERICA

Geophysics ◽  
1975 ◽  
Vol 40 (1) ◽  
pp. 120-120
Author(s):  
Gerald L. Breville
Keyword(s):  
South America ◽  
Gravity Anomaly ◽  
South American ◽  
Bouguer Gravity ◽  
American Continent ◽  
Technical Paper ◽  
Bouguer Gravity Anomaly ◽  
Anomaly Map ◽  
South American Continent

A recently prepared Bouguer gravity anomaly map of South America is the first gravity anomaly representation of the entire South American continent. The technical paper which accompanies the map was presented by Breville et al. (1973). A copy of the map and technical paper may be obtained by writing for DMAAC Technical Paper No. 73-2 to the following address: Director, DMA Aerospace Center, ATTN: RDN, South Annex, St. Louis AFS, Mo 63125.

Israeli penetration in South America (1973-1947)

2021 ◽  
Vol 26 ◽  
pp. 1-23
Keyword(s):  
South America ◽  
Key Words ◽  
Decision Makers ◽  
The Political ◽  
South American ◽  
American Continent ◽  
The South ◽  
Political Decision ◽  
South American Continent

This research is an attempt to uncover the reality and method of Israeli penetration in the South American continent, and aims to draw attention to the weaknesses and mistakes in the role of Arab communities that they had to play in South America, and the position of Arab governments towards that continent. The research was divided into two main axes, as the first dealt with the means of Israeli penetration in South America until 1947, providing a brief overview of the roots of the penetration in the South American continent and the methods it adopted in achieving this. While the second axis focused on the stance of the South American countries on the Arab-Israeli conflict (1947-1973). However, the Israeli infiltration was affecting the political decision-makers in that continent towards the decision to partition Palestine up to the October 1973 war. Key words: the penetration, Palestine, Israel, immigration, Arabs, America

Species diversity and distributions of microdrile earthworms (Annelida, Clitellata, Enchytraeidae) from South America

Zootaxa ◽  
2009 ◽  
Vol 2065 (1) ◽  
pp. 51-68 ◽  
Author(s):  
MARTIN L. CHRISTOFFERSEN
Keyword(s):  
South America ◽  
Sister Group ◽  
Lateral Position ◽  
Nominal Species ◽  
South American ◽  
Dorsal Vessel ◽  
American Continent ◽  
Northeast Region ◽  
Biodiversity Database ◽  
South American Continent

A comprehensive biodiversity database of Enchytraeidae produced 66 nominal species reported to date from South America (Achaeta, 6 species; Buchholzia, 1; Cognettia, 1; Enchytraeus, 3; Fridericia, 5; Grania, 1; Guaranidrilus, 10; Hemienchytraeus, 12; Henlea, 2; Lumbricillus, 7; Marionina, 12; Stephensoniella, 1; Timmodrilus, 1; Tupidrilus, 4). Almost 76% of this fauna (50 species) is endemic to the South American continent. The remaining 16 species are more or less largely distributed. Detailed South American occurrences are provided. This is the first reassessment of South American enchytraeids in 27 years. The group is conspicuoulsy absent from the northeast region of Brazil. Enchytraeidae are microdrile earthworms, representing the sister group of the Crassiclitellata, or megadrile earthworms. This relationship is supported by molecular phylogenies, ontogenetic transformations, ecological evidence, and several morphological synapomorphies (dorsal pores, contractil dorsal vessel, lateral position of dorsal chaetal bundles, and shape of chaetae).

A checklist of marine crustaceans known from Easter Island

Crustaceana ◽  
2016 ◽  
Vol 89 (1) ◽  
pp. 63-84 ◽  
Author(s):  
Patricio De los Ríos Escalante ◽  
Eliana Ibáñez Arancibia
Keyword(s):  
Complex System ◽  
South America ◽  
Endemic Species ◽  
Terrestrial Ecosystem ◽  
Easter Island ◽  
Point Of View ◽  
Marine Crustaceans ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Pacific Asia

Easter Island constitutes the most isolated terrestrial ecosystem in the Pacific Ocean. The fauna of that site is interesting from a biogeographical point of view because species from Pacific Asia and South America can be found there, as well as endemic species. The aim of the present study was to compile a literature review of published records of marine Crustacea from Easter Island with the emphasis on the heterogeneity in habitats reported for each species. The results confirm the presence of species otherwise known from Pacific Asia, South America, as well as the expected endemic species. In spite of the little information that is generally provided in the habitat records for most species, it may still be possible to find a marked heterogeneity of ecosystems, together generating a complex system that warrants more detailed studies.

scholarly journals ENSO-triggered floods in South America: correlation between maximum monthly discharges during strong events

2018 ◽  
Author(s):  
Federico Ignacio Isla
Keyword(s):  
South America ◽  
Saline Water ◽  
High Water ◽  
Water Levels ◽  
South American ◽  
Porto Alegre ◽  
Large Cities ◽  
The Pacific ◽  
Southern Patagonia ◽  
The Pacific Ocean

Abstract. ENSO-triggered floods altered completely the annual discharge of many watersheds of South America. Anomalous years as 1941, 1982–83, 1997–98 and 2015–16 signified enormous fluvial discharges draining towards the Pacific Ocean, but also to the Atlantic. These floods affected large cities built on medium-latitudinal Andes (Lima, Quito, Salta), but also those located at floodplains, as Porto Alegre, Blumenau, Curitiba, Asunción, Santa Fe and Buenos Aires. Maximum discharge months are particular and easily distinguished along time series from watersheds located at the South American Arid Diagonal. At watersheds conditioned by precipitations delivered from the Atlantic or Pacific anti-cyclonic centers, the ENSO-triggered floods are more difficult to discern. The floods of 1941 affected 70,000 inhabitants in Porto Alegre. In 1983, Blumenau city was flooded during several days; and the Paraná River multiplied 15 times the width of its middle floodplain. That year, the Colorado River in Northern Patagonia connected for the last time to the Desagûadero – Chadileuvú – Curacó system and its delta received saline water for the last time. During strong ENSO years the water balances of certain piedmont lakes of Southern Patagonia are modified as the increases in snow accumulations cause high water levels, with a lag of 13 months. The correlation between the maximum monthly discharges of 1982–83 and 1997–98 at different regions and watersheds indicates they can be forecasted for future floods triggered by same phenomena. South American rivers can be classified therefore into ENSO-affected and ENSO-dominated for those within the Arid Diagonal that are exclusively subject to high discharges during those years.

Eocene birds from the western margin of southernmost South America

2010 ◽  
Vol 84 (6) ◽  
pp. 1061-1070 ◽  
Author(s):  
Michel A. Sallaberry ◽  
Roberto E. Yury-Yáñez ◽  
Rodrigo A. Otero ◽  
Sergio Soto-Acuña ◽  
Teresa G. Torres
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
First Record ◽  
South American ◽  
American Continent ◽  
Western Margin ◽  
Geological Units ◽  
South American Continent ◽  
Previous Assumption ◽  
Seymour Island

This study presents the first record of Eocene birds from the western margin of southernmost South America. Three localities in Magallanes, southern Chile, have yielded a total of eleven bird remains, including Sphenisciformes (penguins) and one record tentatively assigned to cf. Ardeidae (egrets). Two different groups of penguins have been recognized from these localities. The first group is similar in size to the smallest taxa previously described from Seymour Island, Marambiornis Myrcha et al., 2002, Mesetaornis Myrcha et al., 2002, and Delphinornis Wiman, 1905. The second recognized group is similar in size to the biggest taxa from Seymour Island; based on the available remains, we recognize the genus Palaeeudyptes Huxley, 1859, one of the most widespread penguin genera in the Southern Hemisphere during the Eocene. The stratigraphic context of the localities indicates a certain level of correlation with the geological units described on Seymour Island. The newly studied materials cast more light on the paleobiogeography of the group, extending the known ranges to the South American continent. In addition to the newly discovered birds, the presence of several taxa of elasmobranchs previously recovered exclusively from Eocene beds in the Southern Hemisphere help to clarify the age of the studied localities, widely discussed during the last decades. This paper verifies the presence of extensive Eocene sedimentary successions with fossil vertebrates along the western margin of southern South America, contrary to the previous assumption that such a record is lacking in Chile.

scholarly journals Subpolar High Anomaly Preconditioning Precipitation over South America

2010 ◽  
Vol 67 (5) ◽  
pp. 1526-1542 ◽  
Author(s):  
Silvina A. Solman ◽  
Isidoro Orlanski
Keyword(s):  
Pacific Ocean ◽  
South America ◽  
Rossby Wave ◽  
South American ◽  
American Continent ◽  
The South ◽  
South Pacific Ocean ◽  
Anomalous Circulation ◽  
Frontal Activity ◽  
South American Continent

Abstract The mechanisms associated with the intraseasonal variability of precipitation over South America during the spring season are investigated with emphasis on the influence of a quasi-stationary anomalous circulation over the southeastern South Pacific Ocean (SEP). A spectral analysis performed to the bandpass-filtered time series of daily precipitation anomalies for the La Plata Basin (LPB) and the South Atlantic convergence zone (SACZ) regions revealed several statistically relevant peaks corresponding to periods of roughly 23 days and 14–16 days—with the lower (higher) frequency peaks more prevalent for the SACZ (LPB). The large-scale circulation patterns preconditioning precipitation variability over both regions were explored by means of a regression analysis performed on the daily 500-hPa geopotential anomaly field provided by the NCEP–NCAR reanalysis dataset. The most prominent feature of the regression fields is the presence of a quasi-stationary anomalous anticyclonic (cyclonic) circulation over the southeastern South Pacific Ocean associated with positive rainfall anomalies over the LPB (SACZ) and, emanating from that high (low), an external Rossby wave propagating northeastward toward the South American continent. The synoptic-scale activity, quantified in terms of a frontal activity index, showed a strong influence on precipitation over the LPB and to a lesser extent over the SACZ. Moreover, the frontal activity is actually modulated by the anomalous high circulation over the SEP region. The behavior of this anomalous circulation may be supported by a positive feedback mechanism that can enhance the response of the high anomaly itself, which in turns reinforces the Rossby wave train propagating toward the South American continent.

scholarly journals Global tropospheric ozone variations from 2003 to 2011 as seen by SCIAMACHY

2016 ◽  
Vol 16 (2) ◽  
pp. 417-436 ◽  
Author(s):  
F. Ebojie ◽  
J. P. Burrows ◽  
C. Gebhardt ◽  
A. Ladstätter-Weißenmayer ◽  
C. von Savigny ◽  
...  
Keyword(s):  
South America ◽  
North Atlantic ◽  
Tropospheric Ozone ◽  
Southern Oscillation ◽  
South American ◽  
Quasi Biennial Oscillation ◽  
The Pacific ◽  
The Tropics ◽  
Biennial Oscillation ◽  
South American Continent

Abstract. An analysis of the tropospheric ozone (O3) columns (TOCs) derived from SCIAMACHY limb-nadir-matching (LNM) observations during the period 2003–2011, focusing on global variations in TOC, is described. The changes are derived using a multivariate linear regression model. TOC shows changes of −0.2 ± 0.4, 0.3 ± 0.4, 0.1 ± 0.5 and 0.1 ± 0.2 % yr−1, which are not statistically significant at the 2σ level in the latitude bands 30–50° N, 20° S–0, 0–20° N and 50–30° S, respectively. Tropospheric O3 shows statistically significant increases over some regions of South Asia (1–3 % yr−1), the South American continent (up to 2 % yr−1), Alaska (up to 2 % yr−1) and around Congo in Africa (up to 2 % yr−1). Significant increase in TOC is determined off the continents including Australia (up to 2 % yr−1), Eurasia (1–3 % yr−1) and South America (up to 3 % yr−1). Significant decrease in TOC (up to −3 % yr−1) is observed over some regions of the continents of North America, Europe and South America. Over the oceanic regions including the Pacific, North Atlantic and Indian oceans, significant decreases in TOC (−1 to −3 % yr−1) were observed. In addition, the response of the El Niño–Southern Oscillation (ENSO) and quasi-biennial oscillation (QBO) to changes in TOC for the period 2003–2011 was investigated. The result shows extensive regions, mostly in the tropics and Northern Hemisphere extratropics, of significant ENSO responses to changes in TOC and a significant QBO response to TOC changes over some regions.

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