scholarly journals Global Change and the Biostratigraphy of North Atlantic Cainozoic deep water Ostracoda

1991 ◽  
Vol 9 (2) ◽  
pp. 119-132 ◽  
Author(s):  
Robin C. Whatley ◽  
Graham P. Coles
Keyword(s):  
Deep Sea ◽  
Middle Eocene ◽  
Drake Passage ◽  
Distribution Patterns ◽  
Global Changes ◽  
Climatic Fluctuations ◽  
Faunal Turnover ◽  
Extinction Rates ◽  
Large Numbers ◽  
Total Fauna

Abstract. The biostratigraphical distribution of deep-sea (>1000m) Palaeocene to Recent benthonic Ostracoda, based on nannofossil NP and NN zones is presented. By excluding very rare species and those represented by juveniles, 184 species are used in constructing range tables from a total fauna for the interval of 230 species. The vertical distribution of these specimens clearly allows of the recognition of all the major stratigraphical units within the Cainozoic and is also sufficiently precise to distinguish most of the nannofossil zones. The principal criteria employed are the first and last appearances of taxa. While eminently possible to create a series of ostracod zones, it is argued that they are best employed in the recognition of particular levels within the existing nannofossil scheme. The interpretation of the range tables is complicated in places by large numbers of Lazarus taxa and also by the fact that many of the ‘originations’ actually record the arrival of immigrants from the Indo-Pacific.Graphs of both simple and cumulative species diversity, and of origination and extinction rates, are used to demonstrate major faunal events such as the first arrival in the area, during the Middle Eocene, of cosmopolitan deep-sea species, or the very marked, but stepped, Palaeogene-Neogene faunal turnover. The distribution patterns of the Ostracoda record such global changes as the formation of the psychrosphere and the inception of a marked thermocline but they do not, as other authors have suggested, indicate a dramatic faunal turnover at the Eocene-Oligocene boundary. The more vigorous circulation patterns of the Oligocene, related to the opening of the Drake Passage, are reflected in enhanced ostracod diversity at that time. Elevated late Oligocene extinction rates may be correlated with cooling consequent upon the growth of polar ice. Similarly, Lower Miocene low levels of diversity may be associated with the closure of the Iberian Portal and the effective isolation of the Tethys. The deep-sea ostracods do not, for the most part, record such events as the mid-Pliocene warming nor Quaternary climatic fluctuations.

Biology of Planktonic Foraminifera

1982 ◽  
Vol 6 ◽  
pp. 51-89 ◽  
Author(s):  
Allan W.H. Bé
Keyword(s):  
Marine Sediments ◽  
Deep Sea ◽  
Planktonic Foraminifera ◽  
Distribution Patterns ◽  
Major Portion ◽  
Utilitarian Value ◽  
Large Numbers ◽  
Biostratigraphic Correlation ◽  
Deep Sea Sediments ◽  
History Of

The history of investigations of planktonic foraminifera leading to their current, wide applications in biostratigraphic correlation of Mesozoic and Cenozoic marine sediments can be traced to the discovery by Owen (1867) of the floating habit of certain foraminifera, later confirmed by Brady (1884), and the recognition by Murray and Renard (1891) that their shells constitute a major portion of deep-sea sediments over large regions of the seafloor. The utilitarian value of planktonic foraminifera in paleoecological analysis is also widely accepted today. Fortunately for students of paleoecology, many species of planktonic foraminifera are still extant and live in large numbers in all oceanic regions. Their areal, vertical and seasonal occurrences have been resolved to such a degree that a global synthesis of their distribution patterns is now available (e.g. Bradshaw, 1959; Belyaeva, 1964; Be and Tolderlund, 1971).

scholarly journals An update on the distribution of Glossina (tsetse flies) at the wildlife-human-livestock interface of Akagera National Park, Rwanda

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Richard S. Gashururu ◽  
Samuel M. Githigia ◽  
Methode N. Gasana ◽  
Richard Habimana ◽  
Ndichu Maingi ◽  
...  
Keyword(s):  
National Park ◽  
Control Strategies ◽  
Glossina Pallidipes ◽  
Distribution Patterns ◽  
Tsetse Flies ◽  
Wet Season ◽  
Chi Square ◽  
Large Numbers ◽  
Surrounding Areas ◽  
Biconical Traps

Abstract Background Glossina (tsetse flies) biologically transmit trypanosomes that infect both humans and animals. Knowledge of their distribution patterns is a key element to better understand the transmission dynamics of trypanosomosis. Tsetse distribution in Rwanda has not been well enough documented, and little is known on their current distribution. This study determined the current spatial distribution, abundance, diversity, and seasonal variations of tsetse flies in and around the Akagera National Park. Methods A longitudinal stratified sampling following the seasons was used. Biconical traps were deployed in 55 sites for 6 consecutive days of each study month from May 2018 to June 2019 and emptied every 48 h. Flies were identified using FAO keys, and the number of flies per trap day (FTD) was used to determine the apparent density. Pearson chi-square (χ2) and parametrical tests (t-test and ANOVA) were used to determine the variations between the variables. The significance (p < 0.05) at 95% confidence interval was considered. Logistic regression was used to determine the association between tsetse occurrence and the associated predictors. Results A total of 39,516 tsetse flies were collected, of which 73.4 and 26.6% were from inside Akagera NP and the interface area, respectively. Female flies accounted for 61.3 while 38.7% were males. Two species were identified, i.e. G. pallidipes [n = 29,121, 7.4 flies/trap/day (FTD)] and G. morsitans centralis (n = 10,395; 2.6 FTD). The statistical difference in numbers was significant between the two species (p = 0.000). The flies were more abundant during the wet season (15.8 FTD) than the dry season (4.2 FTD). Large numbers of flies were trapped around the swamp areas (69.1 FTD) inside the park and in Nyagatare District (11.2 FTD) at the interface. Glossina morsitans was 0.218 times less likely to occur outside the park. The chance of co-existing between the two species reduced outside the protected area (0.021 times). Conclusions The occurrence of Glossina seems to be limited to the protected Akagera NP and a narrow band of its surrounding areas. This finding will be crucial to design appropriate control strategies. Glossina pallidipes was found in higher numbers and therefore is conceivably the most important vector of trypanosomosis. Regional coordinated control and regular monitoring of Glossina distribution are recommended. Graphic Abstract

Interactions between the land snails Theba pisana and Cernuella virgata in the laboratory

2020 ◽  
Author(s):  
Geoff H Baker
Keyword(s):  
Laboratory Experiments ◽  
Distribution Patterns ◽  
Land Snails ◽  
Snail Species ◽  
Agricultural Pests ◽  
Large Numbers ◽  
Small Scales ◽  
Novel Method ◽  
Theba Pisana ◽  
Inhibitory Components

ABSTRACT Two Mediterranean snails, Theba pisana and Cernuella virgata, are agricultural pests in southern Australia. The two species are rarely found together in large numbers in the field, at small scales (&lt;1 m2). In laboratory experiments, the presence of T. pisana reduced the survival of C. virgata, but only when food (carrot + lettuce) was provided. When C. virgata was exposed to only the mucus trails and faeces of T. pisana, produced while feeding on lettuce, both the survival and activity of C. virgata were reduced. When carrot was substituted for lettuce, there was less effect. In addition, when C. virgata was exposed to T. pisana’s faeces only, derived from access to a mix of lettuce and carrot, there was no effect on C. virgata’s survival. The observed reductions in the survival of C. virgata were stronger in autumn (the breeding season for both snail species) compared with spring. Inhibitory components within the mucus trails of T. pisana may (1) help explain the observed distribution patterns of the two species at small scales in the field and (2) provide a novel method for control of pest populations of C. virgata, in some situations.

scholarly journals Geographic contingency, not species sorting, dominates macroevolutionary dynamics in an extinct clade of neogastropods (Volutospina; Volutidae)

Paleobiology ◽  
2021 ◽  
pp. 1-15
Author(s):  
Dana S. Friend ◽  
Brendan M. Anderson ◽  
Warren D. Allmon
Keyword(s):  
Middle Eocene ◽  
Ecological Factors ◽  
Geographic Range ◽  
Late Eocene ◽  
Range Size ◽  
Species Sorting ◽  
Extinction Rates ◽  
Geographic Range Size ◽  
Speciation Rates ◽  
Planktotrophic Larvae

Abstract Rates of speciation and extinction are often linked to many ecological factors, traits (emergent and nonemergent) such as environmental tolerance, body size, feeding type, and geographic range. Marine gastropods in particular have been used to examine the role of larval dispersal in speciation. However, relatively few studies have been conducted placing larval modes in species-level phylogenetic context. Those that have, have not incorporated fossil data, while landmark macroevolutionary studies on fossil clades have not considered both phylogenetic context and net speciation (speciation–extinction) rates. This study utilizes Eocene volutid Volutospina species from the U.S. Gulf Coastal Plain and the Hampshire Basin, U.K., to explore the relationships among larval mode, geographic range, and duration. Based on the phylogeny of these Volutospina, we calculated speciation and extinction rates in order to compare the macroevolutionary effects of larval mode. Species with planktotrophic larvae had a median duration of 9.7 Myr, which compared significantly to 4.7 Myr for those with non-planktotrophic larvae. Larval mode did not significantly factor into geographic-range size, but U.S. and U.K. species do differ, indicating a locality-specific component to maximum geographic-range size. Non-planktotrophs (NPTs)were absent among the Volutospina species during the Paleocene–early Eocene. The relative proportions of NPTs increased in the early middle Eocene, and the late Eocene was characterized by disappearance of planktotrophs (PTs). The pattern of observed lineage diversity shows an increasing preponderance of NPTs; however, this is clearly driven by a dramatic extinction of PTs, rather than higher NPT speciation rates during the late Eocene. This study adds nuance to paleontology's understanding of the macroevolutionary consequences of larval mode.

Pressure and Temperature Adaptation of Cytosolic Malate Dehydrogenases of Shallowand Deep-Living Marine Invertebrates: Evidence for High Body Temperatures in Hydrothermal Vent Animals

1991 ◽  
Vol 159 (1) ◽  
pp. 473-487 ◽  
Author(s):  
ELIZABETH DAHLHOFF ◽  
GEORGE N. SOMERO
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vents ◽  
Elevated Temperatures ◽  
Marine Invertebrates ◽  
Distribution Patterns ◽  
Pressure Effects ◽  
Temperature Adaptation ◽  
Body Temperatures ◽  
Elevated Pressures

Effects of temperature and hydrostatic pressure were measured on cytosolic malate dehydrogenases (cMDHs) from muscle tissue of a variety of shallow- and deep-living benthic marine invertebrates, including seven species endemic to the deep-sea hydrothermal vents. The apparent Michaelis-Menten constant (Km) of coenzyme (nicotinamide adenine dinucleotide, NADH), used to index temperature and pressure effects, was conserved within a narrow range (approximately 15–25 μmoll−1) at physiological temperatures and pressures for all species. However, at elevated pressures, the Km of NADH rose sharply for cMDHs of shallow species (depths of occurrence &gt;Approximately 500 m), but not for the cMDHs of deep-sea species. Cytosolic MDHs of invertebrates from the deep-sea hydrothermal vents generally were not perturbed by elevated temperatures (15–25°C) at in situ pressures, but cMDHs of cold-adapted deep-sea species were. At a single measurement temperature, the Km of NADH for cMDHs from invertebrates from habitats with well-characterized temperatures was inversely related to maximal sustained body temperature. This correlation was used to predict the maximal sustained body temperatures of vent invertebrates for which maximal habitat and body temperatures are difficult to estimate. Species occurring on the ‘smoker chimneys’, which emit waters with temperatures up to 380°C, are predicted to have sustained body temperatures that are approximately 20–25°C higher than vent species living in cooler vent microhabitats. We conclude that, just as adaptation of enzymes to elevated pressures is important in establishing species’ depth distribution patterns, adaptation of pressure-adapted enzymes to temperature is critical in enabling certain vent species to exploit warm-water microhabitats in the vent environment.

scholarly journals Fish Teeth Sr Isotope Stratigraphy and Nd Isotope Variations: New Insights on REY Enrichments in Deep-Sea Sediments in the Pacific

2021 ◽  
Vol 9 (12) ◽  
pp. 1379
Author(s):  
Fenlian Wang ◽  
Gaowen He ◽  
Xiguang Deng ◽  
Yong Yang ◽  
Jiangbo Ren
Keyword(s):  
Deep Sea ◽  
Surface Sediments ◽  
Drake Passage ◽  
Marshall Islands ◽  
Early Oligocene ◽  
The Pacific ◽  
Deep Sea Sediments ◽  
Isotope Stratigraphy ◽  
Topographic Barriers ◽  
Fish Teeth

Rare earth elements and yttrium (REY) are widely recognized as strategic materials for advanced technological applications. Deep-sea sediments from the eastern South Pacific and central North Pacific were first reported as potential resources containing significant amounts of REY that are comparable to, or greater than, those of land-based deposits. Despite nearly a decade of research, quantitative abundances and spatial distributions of these deposits remain insufficient. Age controls are generally absent due to the lack of biostratigraphic constraints. Thus, the factors controlling the formation of REY-rich sediments are still controversial. In this study, the REY contents of surface sediments (<2 m depth) in 14 piston cores from the Middle and Western Pacific were investigated. The results show that deep-sea sediments with high REY contents (>1000 μg/g) were mainly concentrated around seamounts (e.g., the Marshall Islands). The REY contents of surface sediments generally decreased with distance from the seamounts. Biostratigraphic and fish teeth debris (apatite) Sr isotopic stratigraphy of one piston cores (P10) from the Middle Pacific indicate that deep-sea sediments with high REY contents were aged from early Oligocene to early Miocene. Since the opening of the Drake Passage during the early Oligocene, the northward-flowing Antarctic Bottom Water (AABW) would have led to an upwelling of nutrients around seamounts with topographic barriers, and at the same time, AABW would delay the rate of sediment burial to try for enough time for REY entering and enriching in the apatite (fish teeth debris). Understanding the spatial distribution of fertile regions for REY-rich sediments provides guidance for searching for other REY resources in the Pacific and in other oceans.

Rise and fall of rotaliids in the Paleocene-Eocene: the influence of climate and trophic competition

2021 ◽  
Author(s):  
Andrea Benedetti ◽  
Cesare Andrea Papazzoni ◽  
Francesca Romana Bosellini
Keyword(s):  
Middle Eocene ◽  
Ecological Niches ◽  
Trophic Conditions ◽  
Significant Drop ◽  
Abrupt Decrease ◽  
Faunal Turnover ◽  
Number Of Species ◽  
Early Eocene Climatic Optimum ◽  
Climatic Optimum ◽  
Larger Foraminifers

&lt;p&gt;It is largely accepted that climate plays a pivotal role in the diversification of shallow-water communities, with special regards to larger foraminifera (LF), also because increase of surface water temperatures is often accompanied by change in trophic conditions. The shift from widespread eutrophic to oligotrophic conditions in shallow seas probably contributed to the LF differentiation during Paleocene-Eocene times. However, there are few recent attempts to quantify the changes in biodiversity and to correlate them with the global climatic events of the Paleogene. We concentrated our attention on the group of rotaliids, resilient taxa that partially survived after the mass extinction occurred at the end of the Cretaceous.&lt;/p&gt;&lt;p&gt;Our data show that their differentiation at genus level was very rapid, reaching its maximum already in the late Danian SB2 Zone. Specific diversification, instead, culminated in late Thanetian SB4 Zone. A second peak in specific diversity is recorded during the Cuisian (upper part of the Ypresian), then rotaliid diversity steadily declined, as long as other groups of larger foraminifers, especially &lt;em&gt;Alveolina &lt;/em&gt;and &lt;em&gt;Nummulites&lt;/em&gt;, became more competitive and proliferated with a large number of species up to the Bartonian SB17 Zone, when a significant drop in rotaliid biodiversity is recorded.&lt;/p&gt;&lt;p&gt;Differently to other taxonomic groups, i.e., alveolinids and nummulitids, for which a single genus during the whole Eocene generated numerous species, rotaliid genera are usually characterized by a low number of species, possibly due to the re-opening of ecological niches after the abrupt decrease of diversity that followed the PETM event. The competition with other K-strategist LF probably contributed to the decline of rotaliids in the middle Eocene up to the MECO event, where a last dramatic drop is recorded.&lt;/p&gt;&lt;p&gt;The major changes appear strictly linked to warming events such as the Late Danian Event (LDE, starting of the generic diversification of rotaliids), Paleocene Eocene Termal Maximum (PETM, faunal turnover followed by abrupt decrease in both generic and specific diversity), Early Eocene Climatic Optimum (EECO, increase in number of K-strategists under widespread oligotrophic conditions) and Middle Eocene Climatic Optimum (MECO, ultimate drop in diversity and competition with other larger foraminifers).&lt;/p&gt;&lt;p&gt;This study was funded by the Italian Ministry of Education and Research (MIUR), funds PRIN 2017: project &amp;#8220;Biota resilience to global change: biomineralization of planktic and benthic calcifiers in the past, present and future&amp;#8221; (prot. 2017RX9XXY).&lt;/p&gt;

Climate Defined but Not Soil-restricted: The Distribution of a Neotropical tree through Space and Time

2021 ◽  
Author(s):  
Facundo Alvarez ◽  
Paulo S Morandi ◽  
Ben Hur Marimon-Junior ◽  
Reginal Exavier ◽  
Igor Araújo ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Environmental Variables ◽  
Distribution Patterns ◽  
Distribution Models ◽  
Climatic Fluctuations ◽  
Space And Time ◽  
Predictive Variables ◽  
Soil Variables ◽  
Neotropical Tree ◽  
Edaphic Variables

Abstract AimsBrosimum rubescens, a tree species with a Neotropical distribution, can achieve local monodominance in Southern Amazonia forests. Understanding how and why this species varies across space and time is important because the monodominance of some species alters ecosystems complexity. Here we evaluate the fundamental ecological niche of B. rubescens by species distribution models (SDM), combining predictive environmental variables with occurrence points. We specifically aim to 1) determine how the spatial distribution patterns of B. rubescens vary with different environmental predictive variables, and 2) evaluate the temporal and spatial persistence of B. rubescens in the Neotropics. MethodsTo generate the SDMs, the predictive environmental variables were incorporated as main components of climatic, hydric and soil variables. ResultsAll algorithms show higher performance in spatial predictions for hydric variables and for the combination of climatic, hydric and edaphic variables. We identified that the potential niches of B. rubescens seem to be defined by climatic fluctuations, with the edaphic conditions being predictive variables that are not restrictive of their presence on the evaluated spatial scale. From the LMG (Last Glacial Maximum) to the present, the species seems to have increased its spatial amplitude; however, from the present to the future, predictions suggest that B. rubescens will experience a considerable loss of its range. ConclusionsOur findings show the independent and combined effects of different environmental variables, allowing us to identify which limit or facilitate the spatial distribution of B. rubescens. We corroborate the spatial persistence and geographical fidelity of the species' spatial patterns over time.

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