scholarly journals Molecular Ecology and Systematics of Blue  Mussels (Genus Mytilus) (Mytilidae; Bivalvia;  Mollusca) in the Southern Hemisphere

2021 ◽  
Author(s):  
◽  
Kristen Marie Westfall
Keyword(s):  
Gene Flow ◽  
New Zealand ◽  
South America ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Molecular Ecology ◽  
Population Subdivision ◽  
Kerguelen Islands ◽  
Blue Mussels ◽  
The World

<p>The Mytilus edulis species complex, comprised of M. edulis, M. galloprovincialis and M. trossulus, is antitropically distributed in temperate coastal regions of all oceans and main seas of the world. This genus has been heavily studied in the Northern hemisphere but Southern hemisphere populations have received much less attention. This thesis aims to place Southern hemisphere blue mussels into global evolutionary relationships among Mytilus species and investigate aspects of their molecular ecology, including, effects of non-native Northern hemisphere species introductions, biogeography across the Southern hemisphere, regional phylogeographic patterns and population genetics within New Zealand. Southern hemisphere blue mussel phylogenetic reconstruction resulted in the detection of a monophyletic M. galloprovincialis lineage. Two new molecular markers developed with specificity for this lineage and congruence among phylogenetic investigations indicates a panhemispheric distribution of this M. galloprovincialis lineage with implications for naming a new sibling species of the M. edulis complex. This proposed new species, M. meridianus, is distributed in South America, the Kerguelen Islands, New Zealand and Australia at latitudes between ~ 30°S and ~ 55°S. Non-native M. galloprovincialis introduced from the Northern hemisphere have been present in NZ, Australia and Chile for at least ten years and hybridise with native blue mussels. Introgression is observed in New Zealand and Australian but not Chilean hybrid regions. The limited number of introduced mussels in Australia induces hybrid swamping of non-native alleles but an interlineage gender bias towards non-native maternal parents may result in eventual loss of the unique genomic content of native blue mussels in NZ. Southern hemisphere blue mussels form a monophyletic sister clade to a haplogroup shared by Northern hemisphere M. edulis and M. galloprovincialis. Although single gene histories are not congruent with respect to evolutionary relationships within the Northern hemisphere due to introgressive hybridisation after speciation, it is clear that Southern hemisphere blue mussels arose from a species native to the northeast Atlantic Ocean after speciation of the three ‘M. edulis complex’ members. Within the Southern hemisphere monophyletic clade lies three reciprocally monophyletic clades restricted to the geographic regions South America/Kerguelen Islands, New Zealand and Australia. Phylogeographic analysis indicates past gene flow between South American/Kerguelen Islands and New Zealand populations that has ceased at present day and ongoing gene flow between South America and the Kerguelen Islands likely via the West Wind Drift. Within NZ, population subdivision inferred from mtDNA indicates genetic variation is distributed within an east-west phylogeographic split on the North Island. These populations experienced gene flow in the past that has ceased at present day. Microsatellite allele frequencies indicate a different population subdivision within the northwest North Island that has been narrowed down to a 15 km stretch of coastline in a sheltered bay. The abrupt discontinuity within a small geographic area does not conform to classic population subdivision in this broad-cast spawning species, therefore, further investigation into the genomic content of northwest North Island mussels with respect to introgressed non-native genes is warranted. Resolving complex phylogenetic patterns from interspecific introgression is key to understanding the evolutionary history of Southern hemisphere M. galloprovincialis. Further characterisation of hybrid introgression would increase accuracy of (1) inferences of processes contributing to hybridisation dynamics and (2) population subdivision in NZ. Probing the basis for variation of hybridisation dynamics would help to predict the outcomes of Northern hemisphere M. galloprovincialis introductions in other areas of the world.</p>

scholarly journals Molecular Ecology and Systematics of Blue  Mussels (Genus Mytilus) (Mytilidae; Bivalvia;  Mollusca) in the Southern Hemisphere

2021 ◽  
Author(s):  
◽  
Kristen Marie Westfall
Keyword(s):  
Gene Flow ◽  
New Zealand ◽  
South America ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Molecular Ecology ◽  
Population Subdivision ◽  
Kerguelen Islands ◽  
Blue Mussels ◽  
The World

<p>The Mytilus edulis species complex, comprised of M. edulis, M. galloprovincialis and M. trossulus, is antitropically distributed in temperate coastal regions of all oceans and main seas of the world. This genus has been heavily studied in the Northern hemisphere but Southern hemisphere populations have received much less attention. This thesis aims to place Southern hemisphere blue mussels into global evolutionary relationships among Mytilus species and investigate aspects of their molecular ecology, including, effects of non-native Northern hemisphere species introductions, biogeography across the Southern hemisphere, regional phylogeographic patterns and population genetics within New Zealand. Southern hemisphere blue mussel phylogenetic reconstruction resulted in the detection of a monophyletic M. galloprovincialis lineage. Two new molecular markers developed with specificity for this lineage and congruence among phylogenetic investigations indicates a panhemispheric distribution of this M. galloprovincialis lineage with implications for naming a new sibling species of the M. edulis complex. This proposed new species, M. meridianus, is distributed in South America, the Kerguelen Islands, New Zealand and Australia at latitudes between ~ 30°S and ~ 55°S. Non-native M. galloprovincialis introduced from the Northern hemisphere have been present in NZ, Australia and Chile for at least ten years and hybridise with native blue mussels. Introgression is observed in New Zealand and Australian but not Chilean hybrid regions. The limited number of introduced mussels in Australia induces hybrid swamping of non-native alleles but an interlineage gender bias towards non-native maternal parents may result in eventual loss of the unique genomic content of native blue mussels in NZ. Southern hemisphere blue mussels form a monophyletic sister clade to a haplogroup shared by Northern hemisphere M. edulis and M. galloprovincialis. Although single gene histories are not congruent with respect to evolutionary relationships within the Northern hemisphere due to introgressive hybridisation after speciation, it is clear that Southern hemisphere blue mussels arose from a species native to the northeast Atlantic Ocean after speciation of the three ‘M. edulis complex’ members. Within the Southern hemisphere monophyletic clade lies three reciprocally monophyletic clades restricted to the geographic regions South America/Kerguelen Islands, New Zealand and Australia. Phylogeographic analysis indicates past gene flow between South American/Kerguelen Islands and New Zealand populations that has ceased at present day and ongoing gene flow between South America and the Kerguelen Islands likely via the West Wind Drift. Within NZ, population subdivision inferred from mtDNA indicates genetic variation is distributed within an east-west phylogeographic split on the North Island. These populations experienced gene flow in the past that has ceased at present day. Microsatellite allele frequencies indicate a different population subdivision within the northwest North Island that has been narrowed down to a 15 km stretch of coastline in a sheltered bay. The abrupt discontinuity within a small geographic area does not conform to classic population subdivision in this broad-cast spawning species, therefore, further investigation into the genomic content of northwest North Island mussels with respect to introgressed non-native genes is warranted. Resolving complex phylogenetic patterns from interspecific introgression is key to understanding the evolutionary history of Southern hemisphere M. galloprovincialis. Further characterisation of hybrid introgression would increase accuracy of (1) inferences of processes contributing to hybridisation dynamics and (2) population subdivision in NZ. Probing the basis for variation of hybridisation dynamics would help to predict the outcomes of Northern hemisphere M. galloprovincialis introductions in other areas of the world.</p>

scholarly journals Sixty years of radiocarbon dioxide measurements at Wellington, New Zealand 1954–2014

2016 ◽  
Author(s):  
Jocelyn C. Turnbull ◽  
Sara E. Mikaloff Fletcher ◽  
India Ansell ◽  
Gordon Brailsford ◽  
Rowena Moss ◽  
...  
Keyword(s):  
New Zealand ◽  
Southern Ocean ◽  
Co2 Emissions ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Seasonal Cycle ◽  
Fossil Fuel ◽  
Anthropogenic Sources ◽  
Deep Waters ◽  
Cape Grim

Abstract. We present 60 years of Δ14CO2 measurements from Wellington, New Zealand (41° S, 175° E). The record has been extended and fully revised. New measurements have been used to evaluate the existing record and to replace original measurements where warranted. This is the earliest atmospheric Δ14CO2 record and records the rise of the 14C "bomb spike", the subsequent decline in Δ14CO2 as bomb 14C moved throughout the carbon cycle and increasing fossil fuel CO2 emissions further decreased atmospheric Δ14CO2. The initially large seasonal cycle in the 1960s reduces in amplitude and eventually reverses in phase, resulting in a small seasonal cycle of about 2 ‰ in the 2000s. The seasonal cycle at Wellington is dominated by the seasonality of cross-tropopause transport, and differs slightly from that at Cape Grim, Australia, which is influenced by anthropogenic sources in winter. Δ14CO2 at Cape Grim and Wellington show very similar trends, with significant differences only during periods of known measurement uncertainty. In contrast, Northern Hemisphere clean air sites show a higher and earlier bomb 14C peak, consistent with a 1.4-year interhemispheric exchange time. From the 1970s until the early 2000s, the Northern and Southern Hemisphere Δ14CO2 were quite similar, apparently due to the balance of 14C-free fossil fuel CO2 emissions in the north and 14C-depleted ocean upwelling in the south. The Southern Hemisphere sites show a consistent and marked elevation above the Northern Hemisphere sites since the early 2000s, which is most likely due to reduced upwelling of 14C-depleted and carbon-rich deep waters in the Southern Ocean. This developing Δ14CO2 interhemispheric gradient is consistent with recent studies that indicate a reinvigorated Southern Ocean carbon sink since the mid-2000s, and suggests that upwelling of deep waters plays an important role in this change.

Gondwana and Pangea

2004 ◽  
Author(s):  
John J. W. Rogers ◽  
M. Santosh
Keyword(s):  
North America ◽  
South America ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Late Paleozoic ◽  
Northern Asia ◽  
Pan African ◽  
History Of ◽  
Single Block ◽  
Orogenic Belts

Pangea, the most recent supercontinent, attained its condition of maximum packing at ~250 Ma. At this time, it consisted of a northern part, Laurasia, and a southern part, Gondwana. Gondwana contained the southern continents—South America, Africa, India, Madagascar, Australia, and Antarctica. It had become a coherent supercontinent at ~500 Ma and accreted to Pangea largely as a single block. Laurasia consisted of the northern continents—North America, Greenland, Europe, and northern Asia. It accreted during the Late Paleozoic and became a supercontinent when fusion of these continental blocks with Gondwana occurred near the end of the Paleozoic. The configuration of Pangea, including Gondwana, can be determined accurately by tracing the patterns of magnetic stripes in the oceans that opened within it (chapters 1 and 9). The history of accretion of Laurasia is also well known, but the development of Gondwana is highly controversial. Gondwana was clearly a single supercontinent by ~500 Ma, but whether it formed by fusion of a few large blocks or the assembly of numerous small blocks is uncertain. Figure 8.1 shows Gondwana divided into East and West parts, but the boundary between them is highly controversial (see below). We start this chapter by investigating the history of Gondwana, using appendix SI to describe detailed histories of orogenic belts of Pan-African age (600–500-Ma). Then we continue with the development of Pangea, including the Paleozoic orogenic belts that led to its development. The next section summarizes the paleomagnetically determined movement of blocks from the accretion of Gondwana until the assembly of Pangea, and the last section discusses the differences between Gondwana and Laurasia in Pangea. The patterns of dispersal and development of modern oceans are left to chapter 9, and the histories of continents following dispersal to chapter 10. By the later part of the 1800s, geologists working in the southern hemisphere realized that the Paleozoic fossils that occurred there were very different from those in the northern hemisphere. They found similar fossils in South America, Africa, Madagascar, India, and Australia, and in 1913 they added Antarctica when identical specimens were found by the Scott expedition.

Temperate Forests of the Southern Andean Region

2007 ◽  
Author(s):  
Thomas T. Veblen
Keyword(s):  
South America ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Boreal Forests ◽  
Temperate Forests ◽  
High Latitudes ◽  
Andean Region ◽  
Southern South America ◽  
The Andes ◽  
Evergreen Conifers

Although most of the continent of South America is characterized by tropical vegetation, south of the tropic of Capricorn there is a full range of temperate-latitude vegetation types including Mediterranean-type sclerophyll shrublands, grasslands, steppe, xeric woodlands, deciduous forests, and temperate rain forests. Southward along the west coast of South America the vast Atacama desert gives way to the Mediterranean-type shrublands and woodlands of central Chile, and then to increasingly wet forests all the way to Tierra del Fuego at 55°S. To the east of the Andes, these forests are bordered by the vast Patagonian steppe of bunch grasses and short shrubs. The focus of this chapter is on the region of temperate forests occurring along the western side of the southernmost part of South America, south of 33°S. The forests of the southern Andean region, including the coastal mountains as well as the Andes, are presently surrounded by physiognomically and taxonomically distinct vegetation types and have long been isolated from other forest regions. Although small in comparison with the extent of temperate forests of the Northern Hemisphere, this region is one of the largest areas of temperate forest in the Southern Hemisphere and is rich in endemic species. For readers familiar with temperate forests of the Northern Hemisphere, it is difficult to place the temper temperate forests of southern South America into a comparable ecological framework owing both to important differences in the histories of the biotas and to contrasts between the broad climatic patterns of the two hemispheres. There is no forest biome in the Southern Hemisphere that is comparable to the boreal forests of the high latitudes of the Northern Hemisphere. The boreal forests of the latter are dominated by evergreen conifers of needle-leaved trees, mostly in the Pinaceae family, and occur in an extremely continental climate. In contrast, at high latitudes in southern South America, forests are dominated mostly by broadleaved trees such as the southern beech genus (Nothofagus). Evergreen conifers with needle or scaleleaves (from families other than the Pinaceae) are a relatively minor component of these forests.

scholarly journals Brucellosis and tuberculosis in cattle in South America

2018 ◽  
Vol 55 (2) ◽  
pp. e141139
Author(s):  
José Soares Ferreira Neto
Keyword(s):  
New Zealand ◽  
South America ◽  
Epidemiological Data ◽  
Review Article ◽  
South American ◽  
Cattle Population ◽  
High Quality ◽  
The World ◽  
Meat Market ◽  
Epidemiological Situation

In general, European and North American countries, as well as Australia and New Zealand, have already eradicated or reached good levels of control of brucellosis and tuberculosis in cattle. In the rest of the world, however, the epidemiological situation of these two diseases is frequently poorly understood. In this review article, quantified data on these diseases in the South American countries are presented. Initially, the aspects that led the continent to host 25% of the world cattle population are presented, in addition to the aspects that placed the continent at a prominent position in the international meat market. Subsequently the continent was divided into three country groups, considering the size of the cattle population and how well the epidemiological situation of brucellosis and tuberculosis in cattle is quantified. It is argued that countries that do not generate high-quality quantitative epidemiological data on these diseases have serious limitations in outlining and managing control or eradication strategies. Thus, for successful outcomes, at least methodologies to estimate the prevalence of infected herds should be employed.

Correction - The Australasian genera of pericomoid Psychodidae (Diptera) and the status of related Enderlein genera in the neotropics

1989 ◽  
Vol 3 (6) ◽  
pp. 721
Author(s):  
DA Duckhouse
Keyword(s):  
New Zealand ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Sister Group ◽  
New Genera ◽  
The Status ◽  
Taxonomic Problem ◽  
Actual Relationship ◽  
Made In

Australasian pericomoids, psychodids resembling northern hemisphere species of Pericoma Walker (tribe Pericomini), are mostly members of the tribe Maruinini, here re-defined. Amongst Maruinini, they are like several neotropical genera named by Enderlein (1937), but their actual relationship to Enderlein's genera, and hence their identity, has been a long-standing taxonomic problem. Consideration of extensive new collections and observations made in the southern hemisphere now shows that they consist of the following: Genus Notiocharis Eaton. Tribe Maruinini: genus Didicrum Enderlein, and five new genera, Eremolobulosa, Rotundopteryx, Alloeodidicrurn, Satchellomyia and Ancyroaspis. Of these, the Australian Eremolobulosa is the possible sister group of the European Lobulosa Szabo, and the New Zealand genera Satchellomyia and Ancyroaspis are possible sister groups. Of Enderlein's neotropical genera, five classified by Quate (1963) as synonyms, or in one case a subgenus, of Pericoma (Didicrum, Desmioza, Synmormia, Syntomolaba and Podolepria) are recognised as full genera. A key to Australasian pericomoid genera is provided.

Late Paleozoic Floras of the Southern Hemisphere: Distribution, Composition, Paleoecology

1986 ◽  
Vol 15 ◽  
pp. 128-142 ◽  
Author(s):  
Sergio Archangelsky
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Early Carboniferous ◽  
Late Paleozoic ◽  
Geological Time ◽  
The World ◽  
Equatorial Belt ◽  
Cathaysia Flora ◽  
Distribution Composition ◽  
Different Parts

The paleobotanical literature contains frequent references to paleofloristic regions (often called “floral provinces”) for the Late Paleozoic. Halle (1937) published an early map showing the distribution of four different floral associations in Asia, viz. the Glossopteris Flora, the Angara Flora, the European Permo-Carboniferous Flora and the Cathaysia Flora. Gothan and Weylan (1954) completed this map by adding information from different parts of the world. In 1962 Wagner published a general map showing a Permo-Carboniferous Equatorial Belt separating the northern hemisphere Angara Flora from the southern hemisphere Gondwana Flora. The diagrammatic representation by Meyen (1969) shows the increasing diversifications of these floras with geological time. A later version (Meyen in Chaloner and Meyen, 1973, and in Vakhrameiev, et al., 1978) shows an early differentation into two major units, i.e., the Arcto-Carboniferous Kingdom and the Gondwana Kingdom. The former would be subdivided into the Euramerican and Angara areas, to be distinguished from the Early Carboniferous onwards.

scholarly journals The movements of Alpine glaciers throughout the last 10,000 years as sensitive proxies of temperature and climate changes

2020 ◽  
Vol 232 ◽  
pp. 02002
Author(s):  
Walter Kutschera ◽  
Gernot Patzelt ◽  
Joerg M. Schaefer ◽  
Christian Schlüchter ◽  
Peter Steier ◽  
...  
Keyword(s):  
New Zealand ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Climate Changes ◽  
European Alps ◽  
Cosmogenic Isotopes ◽  
The Holocene ◽  
Surface Exposure Dating ◽  
Exposure Dating ◽  
Alpine Glaciers

A brief review of the movements of Alpine glaciers throughout the Holocene in the Northern Hemisphere (European Alps) and in the Southern Hemisphere (New Zealand Southern Alps) is presented. It is mainly based on glacier studies where 14C dating, dendrochronology and surface exposure dating with cosmogenic isotopes is used to establish the chronology of advances and retreats of glaciers. An attempt is made to draw some general conclusions on the temperature and climate differences between the Northern and Southern Hemisphere.

scholarly journals 3. Contributions to the Phenomena of the Zodiacal Light.

1851 ◽  
Vol 2 ◽  
pp. 162-164
Author(s):  
C. Piazzi Smyth
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Zodiacal Light ◽  
The World ◽  
Instrumental Measurement ◽  
Geographical Position

The purport of this paper was to place on record certain observations made during the years 1843–4–5, in the southern hemisphere, at those times of the year when the Zodiacal Light cannot be seen in the Northern hemisphere; to test, by means of these new data,—which, besides the novelty of the geographical position, had the further one of being determined by instrumental measurement,—what laws of the phenomena may be considered to have been satisfactorily made out, and what required further elucidation; and to recommend these latter to the attention of observers situated in more favourable parts of the world than those commanded by European Observatories generally.

Summing up and consideration of future research needs

1975 ◽  
Vol 189 (1096) ◽  
pp. 479-483
Keyword(s):  
Organochlorine Pesticides ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Organic Pollutants ◽  
Equatorial Region ◽  
The Other ◽  
Future Research ◽  
World Production ◽  
Research Needs ◽  
The World

If there is one thing above all else that this meeting has established it is surely that most of the questions that one may ask regarding organic pollutants and their behaviour in the sea cannot be satisfactorily answered at present. It is only, perhaps, in regard to the persistent organohalogen pesticides, DDT and dieldrin in particular, and PCBs, that one can speak with any assurance. We were persuaded by Professor Goldberg and Dr Portmann that, although the peak input to the oceans in the northern hemisphere may have passed in respect of both DDT and dieldrin, this is not so for the equatorial region and the southern hemisphere; the problem has moved southward and the world production and use of organochlorine pesticides is still increasing. Vigilance must therefore be maintained. The use of PCBs, on the other hand, is being generally phased out.

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