Literatura científica selecionada sobre o tema "Southern high latitude marine ecosystems"
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Artigos de revistas sobre o assunto "Southern high latitude marine ecosystems"
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Paterson, J. Terrill, Jay J. Rotella, Kevin R. Arrigo e Robert A. Garrott. "Tight coupling of primary production and marine mammal reproduction in the Southern Ocean". Proceedings of the Royal Society B: Biological Sciences 282, n.º 1806 (7 de maio de 2015): 20143137. http://dx.doi.org/10.1098/rspb.2014.3137.
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Polynyas are areas of open water surrounded by sea ice and are important sources of primary production in high-latitude marine ecosystems. The magnitude of annual primary production in polynyas is controlled by the amount of exposure to solar radiation and sensitivity to changes in sea-ice extent. The degree of coupling between primary production and production by upper trophic-level consumers in these environments is not well understood, which prevents reliable predictions about population trajectories for species at higher trophic levels under potential future climate scenarios. In this study, we find a strong, positive relationship between annual primary production in an Antarctic polynya and pup production by ice-dependent Weddell seals. The timing of the relationship suggests reproductive effort increases to take advantage of high primary production occurring in the months after the birth pulse. Though the proximate causal mechanism is unknown, our results indicate tight coupling between organisms at disparate trophic levels on a short timescale, deepen our understanding of marine ecosystem processes, and raise interesting questions about why such coupling exists and what implications it has for understanding high-latitude ecosystems.
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Arfianti, T., e MJ Costello. "Global biogeography of marine amphipod crustaceans: latitude, regionalization, and beta diversity". Marine Ecology Progress Series 638 (19 de março de 2020): 83–94. http://dx.doi.org/10.3354/meps13272.
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Studying the biogeography of amphipod crustaceans is of interest because they play an important role at lower trophic levels in ecosystems. Because they lack a planktonic larval stage, it has been hypothesized that marine benthic amphipod crustaceans may have short dispersal distances, high endemicity, and spatial turnover in species composition, and consequently high global species richness. In this study, we examined over 400000 distribution records of 4876 amphipod species, and identified 12 regions of endemicity. The number and percent of endemic species peaked at 30°-35°S and coincided with 3 of these regions of high endemicity: Australia, New Zealand, and southern Africa. Pelagic species of marine amphipod crustaceans were more cosmopolitan than benthic species. The latitudinal patterns of richness (alpha, gamma, and ES50) and species turnover were at least bimodal. Most occurrence records and greater alpha and gamma richness were in mid-latitudes, reflecting sampling bias. Both ES50 and beta diversity had similar richness in the tropics, mid-latitudes, and on the Antarctic shelf around 70°S. These 2 indices exhibited a sharp dip in the deep Southern Ocean at 55°S. ES50 peaked at 30°-35°S and a small dip was apparent near the equator at 5°-10°N. Beta diversity was driven mostly by turnover rather than nestedness. These findings support the need for conservation in each realm of species endemicity—and for amphipods, particularly in Antarctica and the coastal mid-latitudes (30°-35°S) of the Southern Hemisphere.
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Contreras, L., J. Pross, P. K. Bijl, R. B. O'Hara, J. I. Raine, A. Sluijs e H. Brinkhuis. "Southern high-latitude terrestrial climate change during the Paleocene–Eocene derived from a marine pollen record (ODP Site 1172, East Tasman Plateau)". Climate of the Past Discussions 10, n.º 1 (20 de janeiro de 2014): 291–340. http://dx.doi.org/10.5194/cpd-10-291-2014.
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Abstract. Reconstructing the early Paleogene climate dynamics of terrestrial settings in the high southern latitudes is important to assess the role of high-latitude physical and biogeochemical processes in the global climate system. However, whereas a number of high-quality Paleogene climate records has become available for the marine realm of the high southern latitudes over the recent past, the long-term evolution of coeval terrestrial climates and ecosystems is yet poorly known. We here explore the climate and vegetation dynamics on Tasmania from the middle Paleocene to the early Eocene (60.7–54.2 Ma) based on a sporomorph record from Ocean Drilling Program (ODP) Site 1172 on the East Tasman Plateau. Our results show that three distinctly different vegetation types thrived on Tasmania under a high-precipitation regime during the middle Paleocene to early Eocene, with each type representing different temperature conditions: (i) warm-temperate forests dominated by gymnosperms that were dominant during the middle and late Paleocene; (ii) cool-temperate forests dominated by southern beech (Nothofagus) and araucarians across the middle/late Paleocene transition interval (~59.5 to ~59.0 Ma); and (iii) paratropical forests rich in ferns that were established during and in the wake of the Paleocene–Eocene Thermal Maximum (PETM). The transient establishment of cool-temperate forests lacking any frost-sensitive elements (i.e., palms and cycads) across the middle/late Paleocene transition interval indicates markedly cooler conditions, with the occurrence of frosts in winter, on Tasmania during that time. The integration of our sporomorph data with previously published TEX86-based sea-surface temperatures from ODP Site 1172 documents that the vegetation dynamics on Tasmania were closely linked with the temperature evolution in the Tasman sector of the Southwest Pacific region. Moreover, the comparison of our season-specific climate estimates for the sporomorph assemblages from ODP Site 1172 with the TEX86L- and TEX86H-based temperature data suggests a warm-season bias of both calibrations for the early Paleogene of the high southern latitudes.
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Contreras, L., J. Pross, P. K. Bijl, R. B. O'Hara, J. I. Raine, A. Sluijs e H. Brinkhuis. "Southern high-latitude terrestrial climate change during the Palaeocene–Eocene derived from a marine pollen record (ODP Site 1172, East Tasman Plateau)". Climate of the Past 10, n.º 4 (24 de julho de 2014): 1401–20. http://dx.doi.org/10.5194/cp-10-1401-2014.
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Abstract. Reconstructing the early Palaeogene climate dynamics of terrestrial settings in the high southern latitudes is important to assess the role of high-latitude physical and biogeochemical processes in the global climate system. However, whereas a number of high-quality Palaeogene climate records has become available for the marine realm of the high southern latitudes over the recent past, the long-term evolution of coeval terrestrial climates and ecosystems is yet poorly known. We here explore the climate and vegetation dynamics on Tasmania from the middle Palaeocene to the early Eocene (60.7–54.2 Ma) based on a sporomorph record from Ocean Drilling Program (ODP) Site 1172 on the East Tasman Plateau. Our results show that three distinctly different vegetation types thrived on Tasmania under a high-precipitation regime during the middle Palaeocene to early Eocene, with each type representing different temperature conditions: (i) warm-temperate forests dominated by gymnosperms that were dominant during the middle and late Palaeocene (excluding the middle/late Palaeocene transition); (ii) cool-temperate forests dominated by southern beech (Nothofagus) and araucarians that transiently prevailed across the middle/late Palaeocene transition interval (~ 59.5 to ~ 59.0 Ma); and (iii) paratropical forests rich in ferns that were established during and in the wake of the Palaeocene–Eocene Thermal Maximum (PETM). The transient establishment of cool-temperate forests lacking any frost-sensitive elements (i.e. palms and cycads) across the middle/late Palaeocene transition interval indicates markedly cooler conditions, with the occurrence of frosts in winter, on Tasmania during that time. The integration of our sporomorph data with previously published TEX86-based sea-surface temperatures from ODP Site 1172 documents that the vegetation dynamics on Tasmania were closely linked with the temperature evolution in the Tasman sector of the Southwest Pacific region. Moreover, the comparison of our season-specific climate estimates for the sporomorph assemblages from ODP Site 1172 with the TEX86L- and TEX86H-based temperature data suggests a warm bias of both calibrations for the early Palaeogene of the high southern latitudes.
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Son, Min Ho, Chung Il Lee, Joo Myun Park, Hyun Jung Kim, Ralf Riedel, Inseo Hwang, Young-Nam Kim e Hae Kun Jung. "The Northward Habitat Expansion of the Korean Top Shell Turbo sazae (Gastropoda: Vetigastropoda: Turbinidae) in the Korean Peninsula: Effects of Increasing Water Temperature". Journal of Marine Science and Engineering 8, n.º 10 (7 de outubro de 2020): 782. http://dx.doi.org/10.3390/jmse8100782.
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Recent global climate change often leads to poleward expansions of habitat range of marine organisms in response to increasing water temperature at high latitude. This study investigated latitudinal distribution patterns of Turbo sazae from 2009 to 2018 along the southern and eastern coasts of Korea to verify whether gradual increases in seawater temperature in the East Sea/Sea of Japan (hereafter East/Japan Sea) accelerate changes in the geographic distribution of T. sazae. Between 2009 and 2018, underwater SCUBA surveys were conducted at 19 subtidal rocky shore habitats from the southern and eastern coast of the Korean Peninsula, including Jeju Island. Additionally, long-term seawater temperature records over the last 40 years (between 1980s and 2010s) from the East/Japan Sea were analyzed to verify how changes of water temperature corresponded to geographical distributions of T. sazae. The habitat range of T. sazae was found to have extended from latitude 34°02′ N to latitude 37°06′ N from 2009 to 2018. Although seawater temperature has gradually increased since the 1990s in the East/Japan Sea, habitat expansion was particularly evident during the rapid rise of coastal seawater temperature in the 2010s. Because the strong northward expansion of the Tsushima Current can accelerate the rise of seawater temperature in the East/Japan Sea, studies of the effects of climate change on marine ecosystems of the Korean Peninsula should include data from monitoring the dynamics of the Tsushima Current.
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Beltran, Roxanne S., A. Marm Kilpatrick, Greg A. Breed, Taiki Adachi, Akinori Takahashi, Yasuhiko Naito, Patrick W. Robinson, Walker O. Smith, Amy L. Kirkham e Jennifer M. Burns. "Seasonal resource pulses and the foraging depth of a Southern Ocean top predator". Proceedings of the Royal Society B: Biological Sciences 288, n.º 1947 (17 de março de 2021): 20202817. http://dx.doi.org/10.1098/rspb.2020.2817.
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Seasonal resource pulses can have enormous impacts on species interactions. In marine ecosystems, air-breathing predators often drive their prey to deeper waters. However, it is unclear how ephemeral resource pulses such as near-surface phytoplankton blooms alter the vertical trade-off between predation avoidance and resource availability in consumers, and how these changes cascade to the diving behaviour of top predators. We integrated data on Weddell seal diving behaviour, diet stable isotopes, feeding success and mass gain to examine shifts in vertical foraging throughout ice break-out and the resulting phytoplankton bloom each year. We also tested hypotheses about the likely location of phytoplankton bloom origination (advected or produced in situ where seals foraged) based on sea ice break-out phenology and advection rates from several locations within 150 km of the seal colony. In early summer, seals foraged at deeper depths resulting in lower feeding rates and mass gain. As sea ice extent decreased throughout the summer, seals foraged at shallower depths and benefited from more efficient energy intake. Changes in diving depth were not due to seasonal shifts in seal diets or horizontal space use and instead may reflect a change in the vertical distribution of prey. Correspondence between the timing of seal shallowing and the resource pulse was variable from year to year and could not be readily explained by our existing understanding of the ocean and ice dynamics. Phytoplankton advection occurred faster than ice break-out, and seal dive shallowing occurred substantially earlier than local break-out. While there remains much to be learned about the marine ecosystem, it appears that an increase in prey abundance and accessibility via shallower distributions during the resource pulse could synchronize life-history phenology across trophic levels in this high-latitude ecosystem.
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Loeb, Valerie J., Eileen E. Hofmann, John M. Klinck, Osmund Holm-Hansen e Warren B. White. "ENSO and variability of the Antarctic Peninsula pelagic marine ecosystem". Antarctic Science 21, n.º 2 (19 de novembro de 2008): 135–48. http://dx.doi.org/10.1017/s0954102008001636.
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AbstractThe West Antarctic Peninsula region is an important source of Antarctic krill (Euphausia superba) in the Southern Ocean. From 1980–2004 abundance and concentration of phytoplankton and zooplankton, krill reproductive and recruitment success and seasonal sea ice extent here were significantly correlated with the atmospheric Southern Oscillation Index and exhibited three- to five-year frequencies characteristic of El Niño–Southern Oscillation (ENSO) variability. This linkage was associated with movements of the Southern Antarctic Circumpolar Current Front and Boundary, a changing influence of Antarctic Circumpolar Current and Weddell Sea waters, and eastward versus westward flow and mixing processes that are consistent with forcing by the Antarctic Dipole high-latitude climate mode. Identification of hydrographic processes underlying ecosystem variability presented here were derived primarily from multi-disciplinary data collected during 1990–2004, a period with relatively stable year-to-year sea ice conditions. These results differ from the overwhelming importance of seasonal sea ice development previously established using 1980–1996 data, a period marked by a major decrease in sea ice from the Antarctic Peninsula region in the late 1980s. These newer results reveal the more subtle consequences of ENSO variability on biological responses. They highlight the necessity of internally consistent long-term multidisciplinary datasets for understanding ecosystem variability and ultimately for establishing well-founded ecosystem management. Furthermore, natural environmental variability associated with interannual- and decadal-scale changes in ENSO forcing must be considered when assessing impacts of climate warming in the Antarctic Peninsula–Weddell Sea region.
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Steneck, Robert S., Michael H. Graham, Bruce J. Bourque, Debbie Corbett, Jon M. Erlandson, James A. Estes e Mia J. Tegner. "Kelp forest ecosystems: biodiversity, stability, resilience and future". Environmental Conservation 29, n.º 4 (dezembro de 2002): 436–59. http://dx.doi.org/10.1017/s0376892902000322.
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Kelp forests are phyletically diverse, structurally complex and highly productive components of coldwater rocky marine coastlines. This paper reviews the conditions in which kelp forests develop globally and where, why and at what rate they become deforested. The ecology and long archaeological history of kelp forests are examined through case studies from southern California, the Aleutian Islands and the western North Atlantic, well-studied locations that represent the widest possible range in kelp forest biodiversity. Global distribution of kelp forests is physiologically constrained by light at high latitudes and by nutrients, warm temperatures and other macrophytes at low latitudes. Within mid-latitude belts (roughly 40–60° latitude in both hemispheres) well-developed kelp forests are most threatened by herbivory, usually from sea urchins. Overfishing and extirpation of highly valued vertebrate apex predators often triggered herbivore population increases, leading to widespread kelp deforestation. Such deforestations have the most profound and lasting impacts on species-depauperate systems, such as those in Alaska and the western North Atlantic. Globally urchin-induced deforestation has been increasing over the past 2–3 decades. Continued fishing down of coastal food webs has resulted in shifting harvesting targets from apex predators to their invertebrate prey, including kelp-grazing herbivores. The recent global expansion of sea urchin harvesting has led to the widespread extirpation of this herbivore, and kelp forests have returned in some locations but, for the first time, these forests are devoid of vertebrate apex predators. In the western North Atlantic, large predatory crabs have recently filled this void and they have become the new apex predator in this system. Similar shifts from fish- to crab-dominance may have occurred in coastal zones of the United Kingdom and Japan, where large predatory finfish were extirpated long ago. Three North American case studies of kelp forests were examined to determine their long history with humans and project the status of future kelp forests to the year 2025. Fishing impacts on kelp forest systems have been both profound and much longer in duration than previously thought. Archaeological data suggest that coastal peoples exploited kelp forest organisms for thousands of years, occasionally resulting in localized losses of apex predators, outbreaks of sea urchin populations and probably small-scale deforestation. Over the past two centuries, commercial exploitation for export led to the extirpation of sea urchin predators, such as the sea otter in the North Pacific and predatory fishes like the cod in the North Atlantic. The large-scale removal of predators for export markets increased sea urchin abundances and promoted the decline of kelp forests over vast areas. Despite southern California having one of the longest known associations with coastal kelp forests, widespread deforestation is rare. It is possible that functional redundancies among predators and herbivores make this most diverse system most stable. Such biodiverse kelp forests may also resist invasion from non-native species. In the species-depauperate western North Atlantic, introduced algal competitors carpet the benthos and threaten future kelp dominance. There, other non-native herbivores and predators have become established and dominant components of this system. Climate changes have had measurable impacts on kelp forest ecosystems and efforts to control the emission of greenhouse gasses should be a global priority. However, overfishing appears to be the greatest manageable threat to kelp forest ecosystems over the 2025 time horizon. Management should focus on minimizing fishing impacts and restoring populations of functionally important species in these systems.
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Rodgers, K. B., J. Lin e T. L. Frölicher. "Emergence of multiple ocean ecosystem drivers in a large ensemble suite with an Earth system model". Biogeosciences 12, n.º 11 (3 de junho de 2015): 3301–20. http://dx.doi.org/10.5194/bg-12-3301-2015.
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Abstract. Marine ecosystems are increasingly stressed by human-induced changes. Marine ecosystem drivers that contribute to stressing ecosystems – including warming, acidification, deoxygenation and perturbations to biological productivity – can co-occur in space and time, but detecting their trends is complicated by the presence of noise associated with natural variability in the climate system. Here we use large initial-condition ensemble simulations with an Earth system model under a historical/RCP8.5 (representative concentration pathway 8.5) scenario over 1950–2100 to consider emergence characteristics for the four individual and combined drivers. Using a 1-standard-deviation (67% confidence) threshold of signal to noise to define emergence with a 30-year trend window, we show that ocean acidification emerges much earlier than other drivers, namely during the 20th century over most of the global ocean. For biological productivity, the anthropogenic signal does not emerge from the noise over most of the global ocean before the end of the 21st century. The early emergence pattern for sea surface temperature in low latitudes is reversed from that of subsurface oxygen inventories, where emergence occurs earlier in the Southern Ocean. For the combined multiple-driver field, 41% of the global ocean exhibits emergence for the 2005–2014 period, and 63% for the 2075–2084 period. The combined multiple-driver field reveals emergence patterns by the end of this century that are relatively high over much of the Southern Ocean, North Pacific, and Atlantic, but relatively low over the tropics and the South Pacific. For the case of two drivers, the tropics including habitats of coral reefs emerges earliest, with this driven by the joint effects of acidification and warming. It is precisely in the regions with pronounced emergence characteristics where marine ecosystems may be expected to be pushed outside of their comfort zone determined by the degree of natural background variability to which they are adapted. The results underscore the importance of sustained multi-decadal observing systems for monitoring multiple ecosystems drivers.
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Murray, Alison E., e Joseph J. Grzymski. "Diversity and genomics of Antarctic marine micro-organisms". Philosophical Transactions of the Royal Society B: Biological Sciences 362, n.º 1488 (21 de maio de 2007): 2259–71. http://dx.doi.org/10.1098/rstb.2006.1944.
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Marine bacterioplanktons are thought to play a vital role in Southern Ocean ecology and ecosystem function, as they do in other ocean systems. However, our understanding of phylogenetic diversity, genome-enabled capabilities and specific adaptations to this persistently cold environment is limited. Bacterioplankton community composition shifts significantly over the annual cycle as sea ice melts and phytoplankton bloom. Microbial diversity in sea ice is better known than that of the plankton, where culture collections do not appear to represent organisms detected with molecular surveys. Broad phylogenetic groupings of Antarctic bacterioplankton such as the marine group I Crenarchaeota, α-Proteobacteria ( Roseobacter -related and SAR-11 clusters), γ-Proteobacteria (both cultivated and uncultivated groups) and Bacteriodetes-affiliated organisms in Southern Ocean waters are in common with other ocean systems. Antarctic SSU rRNA gene phylotypes are typically affiliated with other polar sequences. Some species such as Polaribacter irgensii and currently uncultivated γ-Proteobacteria (Ant4D3 and Ant10A4) may flourish in Antarctic waters, though further studies are needed to address diversity on a larger scale. Insights from initial genomics studies on both cultivated organisms and genomes accessed through shotgun cloning of environmental samples suggest that there are many unique features of these organisms that facilitate survival in high-latitude, persistently cold environments.
Teses / dissertações sobre o assunto "Southern high latitude marine ecosystems"
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Maturana, Martínez Claudia. "Diversity and community composition of active microbial communities in southern high latitude ecosystems". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS134.
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Les écosystèmes marins des hautes latitudes méridionales (HLME) sont très sensibles au changement climatique, ayant un impact sur les processus physiques, chimiques et biologiques. Cependant, leur rôle important dans la modulation du climat et la circulation des masses d'eau contraste avec le nombre relativement faible d'études sur leur fonctionnement. Relativement peu d'études sur la structure de la communauté bactérioplanctonique ont été rapportées pour le sud de la Patagonie chilienne et pour l'océan Austral (SO) à grande échelle, et aucune n'a ciblé la fraction active de la communauté bactérioplanctonique. Nous avons utilisé le séquençage de l'ARNr 16S pour analyser et décrire la structure communautaire des communautés bactérioplanctoniques actives dans le sud de l'HLME. L'objectif principal de cette thèse était de caractériser la diversité et l'abondance des communautés de bactérioplancton le long de gradients environnementaux et géographiques dans le sud de HLME. Tout d'abord, nous avons cherché à savoir si les fjords voisins du sud de la Patagonie chilienne, avec un climat et une localisation similaires mais des apports d'eau douce différents, présentaient des communautés différentes. Deuxièmement, nous avons étudié les changements interannuels subis par la communauté bactérioplanctonique du fjord de Yendegaia. Troisièmement, nous avons examiné la structure spatiale à grande échelle de la communauté bactérioplanctonique le long d'un transect traversant le secteur Pacifique du SO. Nos résultats montrent que les communautés bactérioplanctoniques du pôle sud sont structurées en fonction de paramètres physiques, chimiques et biologiques caractéristiques de la zone. De plus, nous avons également démontré que les changements des paramètres environnementaux, spatiaux et temporels affectent la structure des communautés bactérioplanctoniques. Ainsi, nous soulignons l'importance des études d'écologie microbienne dans les zones sensibles au changement climatique global comme le sud de l'HLMESouthern high latitudes marine ecosystems (HLME) are highly sensitive to climate change, impacting physical, chemical, and biological processes, however, their prominent role in climate modulation and water masses circulation, contrast with the relatively low number of studies on their functioning. Relatively few studies on bacterioplankton community structure have been reported for southern Chilean Patagonia and for the Southern Ocean (SO) on a large scale, and none have targeted the active fraction of the bacterioplankton community. We used 16S rRNA sequencing to analyze and describe the community structure of the active bacterioplankton communities in southern HLME. The main objective of this thesis was to characterize de diversity and abundance of bacterioplankton communities along environmental and geographical gradients in southern HLME. First, we investigated whether nearby fjords of the southern Chilean Patagonia, with similar climate and location but different freshwater inflows, had different communities. Second, we investigated interannual changes experienced by the bacterioplankton community of the Yendegaia fjord. Third, we examined the large-scale spatial structure of the bacterioplankton community along a transect across the Pacific sector of the SO. Ours results show that southern polar bacterioplanktonic communities are structured according to physical, chemical, and biological parameters characteristic of the area. In addition, we also demonstrated that changes in environmental, spatial, and temporal parameters affect the structure of bacterioplanktonic communities. Thus, highlighting the importance of microbial ecology studies in areas sensitive to global climate change such as southern HLME
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Saunders, Ryan Alexander. "Ecological investigations of euphausiids at high latitudes". Thesis, St Andrews, 2007. http://hdl.handle.net/10023/347.
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Lewis, PN. "Keeping the coastlines of the Southern Ocean pest-free : hazards, risks and management of non-indigenous species in high latitude marine environments". Thesis, 2007. https://eprints.utas.edu.au/20654/1/whole_LewisPatrickNeil2007_thesis.pdf.
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Invasive species are a prominent threat to global biodiversity. In the marine environment of the Southern Ocean, the rate of delivery, establishment and the subsequent impacts of non-indigenous species remains poorly understood. Furthermore, the absence of dedicated monitoring and effective baselines makes it difficult to recognize the presence of invasive populations. It is now understood that several introduction pathways capable of delivering marine species operate in this region, and the first introduced marine species in the Antarctic continent was recently reported. By analysing various stages in the transport pathway, this work provides key information to supplement our current understanding of this threat.
In the Southern Ocean, the natural transport mechanism for shallow-water marine organisms provided by kelp rafts is being augmented by plastic debris and shipping activity. Plastic debris provides additional opportunities for dispersal of invasive organisms, but these dispersal routes are passive, dependent on ocean currents, and already established. In contrast, ships create novel pathways, moving across currents and often visiting many locations over short periods of time. Vessel traffic thus poses the most likely mechanism by which exotic species may be introduced to the Southern Ocean. While this hazard incorporates a variety of specific mechanisms such as ballast water, entrained objects and hull fouling, an assessment of these pathways demonstrates that hull-fouling communities are the most likely avenue for marine introductions.
Introductions can also occur at the level of the genotype. Remote populations of Mytilus galloprovincialis (blue mussels) from the New Zealand sub-Antarctic islands possess a unique genetic structure and should be considered as a sub-species within the Mytilus complex. Such populations represent valuable examples of genetic information in a species with a genetic structure clearly homogenized through human transport opportunities. These unique populations are at risk of hybridization with cosmopolitan gene-lines sourced from temperate ports. The ability of invasive species to gain rapid anthropogenic dispersal also threatens the genetic diversity of the entire species. This loss of genetic diversity is an additional component of biodiversity loss associated with the spread of non-indigenous species.
By identifying high risk species, surveillance and monitoring activities can focus upon species of concern allowing resources to be allocated more efficiently. Temperate fouling communities were collected on settlement plates and exposed to thermal conditions replicating Southern Ocean environments to determine high risk species. A wide variety of temperate species survive the thermal conditions of the sub-Antarctic islands and at least eight species can survive in the waters of Antarctica. Three species (Halicarcinus innominatus, Petrolisthes elongatus and Mytilus galloprovincialis) are capable of spawning and completing their entire life-history cycle at Southern Ocean temperatures.
The data collected in this thesis have been incorporated into an assessment of the risk of marine introduction to the sub-Antarctic Macquarie Island Marine Park. Analyses of environmental tolerances show that at least seven species of invasive marine pests, resident in ports in Australia and New Zealand, could potentially survive and complete their life cycles in the water temperatures that are found at Macquarie Island. Management recommendations include the instigation of baseline monitoring programs and operational procedures aimed to minimize the ship-based transport of marine species.
Capítulos de livros sobre o assunto "Southern high latitude marine ecosystems"
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Armesto, Juan J., Cecilia Smith-Ramírez e Carlos Sabag. "The Importance of Plant-Bird Mutualisms in the Temperate Rainforest of Southern South America". In High-Latitude Rainforests and Associated Ecosystems of the West Coast of the Americas, 248–65. New York, NY: Springer New York, 1996. http://dx.doi.org/10.1007/978-1-4612-3970-3_12.
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Arroyo, Mary T. Kalin, Magaly Riveros, Alejandro Peñaloza, Lohengrin Cavieres e Ana Maria Faggi. "Phytogeographic Relationships and Regional Richness Patterns of the Cool Temperate Rainforest Flora of Southern South America". In High-Latitude Rainforests and Associated Ecosystems of the West Coast of the Americas, 134–72. New York, NY: Springer New York, 1996. http://dx.doi.org/10.1007/978-1-4612-3970-3_8.
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Sell, Anne F., Graham P. von Maltitz, Holger Auel, Arne Biastoch, Maya Bode-Dalby, Peter Brandt, Sabrina E. Duncan et al. "Unique Southern African Terrestrial and Oceanic Biomes and Their Relation to Steep Environmental Gradients". In Sustainability of Southern African Ecosystems under Global Change, 23–88. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-10948-5_2.
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AbstractThe southern African subcontinent and its surrounding oceans accommodate globally unique ecoregions, characterized by exceptional biodiversity and endemism. This diversity is shaped by extended and steep physical gradients or environmental discontinuities found in both ocean and terrestrial biomes. The region’s biodiversity has historically been the basis of life for indigenous cultures and continues to support countless economic activities, many of them unsustainable, ranging from natural resource exploitation, an extensive fisheries industry and various forms of land use to nature-based tourism.Being at the continent’s southern tip, terrestrial species have limited opportunities for adaptive range shifts under climate change, while warming is occurring at an unprecedented rate. Marine climate change effects are complex, as warming may strengthen thermal stratification, while shifts in regional wind regimes influence ocean currents and the intensity of nutrient-enriching upwelling.The flora and fauna of marine and terrestrial southern African biomes are of vital importance for global biodiversity conservation and carbon sequestration. They thus deserve special attention in further research on the impacts of anthropogenic pressures including climate change. Excellent preconditions exist in the form of long-term data sets of high quality to support scientific advice for future sustainable management of these vulnerable biomes.
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Mehlhorn, Paul, Brent Newman e Torsten Haberzettl. "Comparison of Different Normalisers for Identifying Metal Enrichment of Sediment: A Case Study from Richards Bay Harbour, South Africa". In Sustainability of Southern African Ecosystems under Global Change, 787–814. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-10948-5_27.
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AbstractSouth Africa’s ecosystems are challenged in various ways by anthropogenic effects, such as land-use change, leading to soil erosion in concert with industrial or agricultural pollution, leading to an increase in pollutants in final depositional systems. Here we focus on metals in the marine environment of Richards Bay Harbour. The use for Al, Fe, Rb, Ti and the silt fraction of the sediment as normalisers of Cr, Cu, Co and Pb concentrations in sediment is compared to determine if they provide the same understanding on the enrichment. Baseline metal concentration models were defined and Enrichment Factors calculated to quantify the magnitude of enrichment.Exceedingly high Cr and Cu concentrations in defined parts of the harbour lead to similar trends rather than a similar effectiveness of the normalisers. Probable biogeochemical processes hinder the effectiveness of Fe and geological background or hydrodynamic properties hinder the effectiveness of Ti as normaliser. Differences in the spatial extent of sediment identified as enriched and the area where metal concentrations exceed guidelines detracts from fully appreciating the extent of metal contamination of sediment using guidelines, with management implications. Furthermore, in the case of Cu, the guidelines for this metal might be underproductive.
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Kloeppel, Brian D., e Barton D. Clinton. "Drought Impacts on Tree Growth and Mortality of Southern Appalachian Forests". In Climate Variability and Ecosystem Response in Long-Term Ecological Research Sites. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195150599.003.0009.
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The Coweeta LTER Program represents the eastern deciduous forests of the southern Appalachian Mountains in the United States. Coweeta Hydrologic Laboratory was established in 1934 and hence has a long record of climate measurement and vegetation response to both natural and human disturbance (Swank and Crossley 1988). The general climate of the area is classified as marine humid temperate because of high moisture and mild temperatures (Critchfield 1966; Swift et al. 1988). These conditions have favored the evolution of high species diversity in organisms in the southern Appalachians at many levels. In recent years, however, Coweeta has experienced several droughts that have caused significant tree growth reduction and increased mortality rates (Swift et al. 1990; Clinton et al. 1993; Vose and Swank 1994; McNulty and Swank 1995). In this chapter, we describe the general climate and features of Coweeta as well as the impact of droughts on tree growth and mortality. The timescale of this climate variability is annual, with the potential for preexisting soil moisture conditions either providing a buffer or further exacerbating the drought conditions. Mean annual precipitation at Coweeta Hydrologic Laboratory (latitude 35º14' N, longitude 83º26' W) varies from 1798 mm at the base climate station (686 m) to 2373 mm at the high-elevation Mooney Gap climate station (1364 m). Mean annual growing season precipitation, defined as May to October, is 782 mm at the base climate station (figure 3.1). Mean annual streamflow from watershed 18, a low-elevation reference watershed, is 1011 mm or 56% of precipitation (figure 3.1). Short-duration thundershowers at Coweeta are typical for midsummer and fall with occurrences of large rainfalls stimulated by tropical disturbances near the Atlantic or Gulf coasts. Forty-nine percent of the 133 storms each year have a total precipitation amount less than 5 mm, and 69% of the annual precipitation falls with an intensity less than 10 mm per hour. Snow is a minor part of the annual precipitation, averaging 2–5% depending on elevation. Snow cover rarely lasts for more than 3 or 4 days, even on the upper slopes.
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Smith, Raymond C., e Xiaojun Yuan. "The Quasi-Quintennial Timescale—Synthesis". In Climate Variability and Ecosystem Response in Long-Term Ecological Research Sites. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195150599.003.0020.
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The El Nino–Southern Oscillation (ENSO) is one of the most important contributors to interannual variability on Earth (Diaz and Markgraf 2000). It is an aperiodic phenomenon that tends to reoccur within the range of 2 to 7 years, and it is manifest by the alternation of extreme warm (El Niño) and cold (La Niña) events. There is also evidence (Allen 2000) that the aperiodic ENSO phenomenon must be considered in conjunction with climate fluctuations at decadal to multidecadal time frames that may modulate ENSO’s lower frequency variability. Numerous studies show global climatic impacts associated with the ENSO phenomenon. Further, there is considerable evidence to indicate that ENSO impacts the climate of both middle and high latitudes, and a recent analysis (figure S.1, discussed below) provides a global picture of warm versus cold ENSO conditions. Consequently, it is not surprising that many LTER sites, from the Arctic to Antarctic, show evidence of ENSO-related fluctuations in environmental variables. The quasi-quintennial timescale of variability is second only to seasonal variability in driving worldwide weather patterns. Consequently, an important theme in part II is the worldwide influence of ENSO-related climate variability and the teleconnected spatial patterns of this variability. Also, a common theme for several ecosystems discussed in this section is their high sensitivity to small climatic changes that are subsequently amplified and cascaded through the system. For example, the narrow temperature threshold for an ice-to-water phase change may create a pronounced nonlinear ecosystem response to what is a relatively small temperature shift (as demonstrated for the McMurdo Dry Valleys). Or alternatively, this narrow temperature threshold may shift a sea ice–dominated ecosystem (Palmer LTER) to a more oceanic marine ecosystem by reducing the seasonality and magnitude of the sea ice habitat. Such nonlinear amplifications of small climatic changes can increase the ecological response and make it more detectable within the natural background of variability. We explore these themes here. To illustrate the global footprint of ENSO variability, composites of yearly averaged El Niño and La Niña conditions for surface air temperature (SAT) and sea surface temperature (SST, Reynolds and Smith 1994) were generated.
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Mack, Greg H., e Barbara A. Nolen. "Regional Setting of the Jornada Basin". In Structure and Function of a Chihuahuan Desert Ecosystem. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195117769.003.0006.
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Within the area around Las Cruces, New Mexico, is a network of studies both at the Jornada Experimental Range (JER) and the Chihuahuan Desert Rangeland Research Center (CDRRC), which includes the Desert Soil-Geomorphology Project. All of these research entities are in the Chihuahuan Desert; this chapter describes the geologic history and development of landscapes that are important elements to our understanding of this ecosystem and its dynamic nature. Southern New Mexico consists of C3 shrubs and C4 grasses in the lower elevations surrounded by C3 woodlands and juniper savannas in the higher elevations (Dick-Peddie 1993; see also chapter 10). Although the boundary of the Chihuahuan Desert has differed slightly depending on whether it was based on vegetative or climatic criteria, the boundary most widely used is based on a de Martonne aridity index of 10 (Schmidt 1979). Like many deserts of the world, the Chihuahuan Desert is in a zone of dry, high-pressure cells near 30° latitude; is relatively far from marine moisture sources; and occupies a position in which mountains scavenge moisture from weather fronts (Strahler and Strahler 1987). The orographic influence is especially important in Mexico, which contains about threefourths of the Chihuahuan Desert, because the desert is bounded to the west by the Sierra Madre Occidental and to the east by the Sierra Madre Oriental Mountains. The basin and range province consists of north–south trending mountain ranges and broad intervening desert basins that at the Jornada Basin site is the product of the Rio Grande rift tectonic system, which has been active since middle tertiary time (Seager 1975; Seager et al. 1984). Erosion of the steeply tilted mountain ranges has been the main source of sediment for the filling of the intermontane basins. Vertically, sedimentary deposits are separated by paleosols that indicate quiescent times following periods of erosion and sedimentation. As the basins filled with sediment, pore spaces between sediment particles filled with water from rain, making these structural basins large reservoirs of ground water (Hawley and Lozinsky 1992; Hawley and Kennedy 2004).
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Crame, J. Alistair. "Evolution of high-latitude molluscan faunas". In Origin and Evolutionary Radiation of the Mollusca, 119–31. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780198549802.003.0010.
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Abstract Two central, and interrelated, questions lie at the heart of investigations into the evolutionary history of polar and high- latitude marine biotas: how old are they?, and how isolated have they been through time? There is, perhaps, still a widespread impression that polar biotas are in some way less mature than their low-latitude counterparts. Because of repeated glaciations through the late Neogene and Quaternary, it is assumed generally that many taxa are still re-adjusting to life in high latitudes; by comparison, the more benign low- latitude regions are thought to be sites where life has proliferated comparatively undisturbed for long periods of time (see Dunbar, 1968 and references therein for a fuller development of this theme). Whereas there may have been open marine connections between the Arctic and North Atlantic oceans over at least the last 30 million years (=m.y.) (Marincovich et al., 1990), links between the Arctic and North Pacific oceans were severed from the Late Cretaceous to late Pliocene (65-3 m.y. ago). A common view of the Southern Ocean marine fauna is that it is the product of a considerable period of evolutionary isolation (e.g. Knox and Lowry, 1977; Lipps and Hickman, 1982).
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Chaloupka, Milani. "Southern Great Barrier Reef Green Sea Turtle (Chelonia mydas) Stock: Consequences of Local Sex-Biased Harvesting". In Species Conservation and Management, 340–54. Oxford University PressNew York, NY, 2004. http://dx.doi.org/10.1093/oso/9780195166460.003.0030.
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Abstract The green turtle (Chelonia mydas) is a marine species with a broad pantropical distribution (Bowen et al. 1992) and is the most abundant large herbivore in marine ecosystems (Bjorndal et al. 2000). The southern Great Barrier Reef (sGBR) green turtle stock is one of the most important breeding populations of green turtles in the western South Pacific region (FitzSimmons et al. 1997) with benthic foraging grounds in Australian, Indonesian, Papua New Guinean, Coral Sea, and New Caledonian waters (Limpus et al. 1992). The Great Barrier Reef and coastal Queensland benthic habitat component of this stock includes a spatially disjunct metapopulation with foraging grounds that span 12° latitude and 1800 km with foraging grounds that range from tropical waters in the northern Great Barrier Reef (nGBR) to warm temperate waters in southern coastal Queensland (Figure 30.1) (Chaloupka 2002a). Pelagic juveniles recruit to these benthic habitat foraging grounds after pelagic development in the western South Pacific Ocean (Limpus and Chaloupka 1997).
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"The Ecology of Juvenile Salmon in the Northeast Pacific Ocean: Regional Comparisons". In The Ecology of Juvenile Salmon in the Northeast Pacific Ocean: Regional Comparisons, editado por Marc Trudel, Mary E. Thiess, Cynthia Bucher, Edward V. Farley, R. Bruce MacFarlane, Edmundo Casillas, Joseph Fisher, John F. T. Morris, James M. Murphy e David W. Welch. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569957.ch8.
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Abstract.—Size-selective mortality combined with longer winters at high-latitudes is expected to exert strong directional selection on size, growth, and energy use and storage capacity in northern fish populations. Here, we tested the hypotheses that juvenile Pacific salmon <em>Oncorhynchus </em>spp. grow faster, reach larger size, and accumulate higher energy reserves in the marine environment at northern latitudes using juvenile Chinook salmon <em>O. tshawystcha </em>and coho salmon <em>O. kisutch </em>collected on the continental shelf from the California coast to the Bering Sea. Size reached at the end of the growing season, the quantity of energy stored prior to the onset of winter, and summer growth of juvenile Chinook and coho salmon during their first year at sea varied significantly among regions of the continental shelf. Latitudinal trends were detected for the fall size of subyearling and yearling Chinook salmon and storage energy in yearling Chinook salmon. However, they were opposite to expectations, with values decreasing from southern to northern areas. Latitudinal trends were also apparent for summer growth in juvenile yearling Chinook salmon. However, in contrast to fall size and storage energy, higher growth rates were generally observed in northern rather than in southern regions. Similarly, summer growth generally decreased from northern to southern regions in juvenile coho salmon. Storage energy did not exhibit a consistent trend with latitude in juvenile subyearling Chinook salmon and coho salmon. The different response of juvenile Chinook salmon and coho salmon to a latitudinal cline in temperature and the length of the growing season suggest that both species utilize the marine environment differently. We suggest that regional variations in juvenile salmon growth and energy accumulation may result from differences in prey quality (i.e., lipids), diet, and interspecific competition for prey resources.
Relatórios de organizações sobre o assunto "Southern high latitude marine ecosystems"
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Stone, Robert P., Stephen D. Cairns, Dennis M. Opresko, Gary C. Williams e Michele M. Masuda. A guide to the corals of Alaska. US Department of Commerce, NOAA, NMFS Scientific Publications Office, janeiro de 2024. http://dx.doi.org/10.7755/pp.23.
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The Magnuson-Stevens Fishery Conservation and Management Reauthorization Act of 2006 mandat¬ed the research and management of the nation’s deep-sea coral resources through establishment of the National Oceanic and Atmospheric Administra¬tion’s Deep Sea Coral Research and Technology Program. The challenge for Alaska was daunting, where expansive, world-class fisheries often coincided with extraordinarily rich coral habitats for a high-latitude region. The first chal¬lenge was to inventory known locations of deep-sea corals. Many coral records and some museum collections existed from Alaska, but the taxonomy of cor¬als was little studied and field iden¬tification of corals was problematic. Formal bycatch programs and research activities in recent decades provided many more specimens for taxonomic study, but guides to species were largely incomplete, inaccurate, and outdated given the fast pace of species discovery in Alaska. We provide a comprehen¬sive, up-to-date guide, detailing 161 coral taxa identified from museum collections, primary literature, and video records. Each profile includes a description, images for each taxon, taxonomic history, biology, ecology, geographical distribution, and habitat, including depth distribution. Corals are found in the six regions of Alaska but the coral fauna of the Aleutian Islands is by far the most species rich. The state of taxonomy for some coral groups is ex¬cellent, while others require additional collections and more taxonomic work. Construction of this guide resulted in descriptions of several antipatharian species, published separately from this guide (Alternatipathes mirabilis, Bathypathes alaskensis, B. ptiloides, B. tiburonae, and Parantipathes pluma) and the scleractinian Flabellum (Flabel¬lum) oclairi Cairns, sp. nov. described herein. The guide provides informa¬tion for targeting new collections and identifying areas of high abundance and indicator species of vulnerable marine ecosystems. Stakeholders can now more adequately assess Alaska’s coral resources and risks from natural and anthropogenic stressors.