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  • 1
    Publication Date: 2024-03-15
    Description: Prior exposure to variable environmental conditions is predicted to influence the resilience of marine organisms to global change. We conducted complementary 4-month field and laboratory experiments to understand how a dynamic, and sometimes extreme, environment influences growth rates of a tropical reef-building crustose coralline alga and its responses to ocean acidification (OA). Using a reciprocal transplant design, we quantified calcification rates of the Caribbean coralline Lithophyllum sp. at sites with a history of either extreme or moderate oxygen, temperature, and pH regimes. Calcification rates of in situ corallines at the extreme site were 90% lower than those at the moderate site, regardless of origin. Negative effects of corallines originating from the extreme site persisted even after transplanting to more optimal conditions for 20 weeks. In the laboratory, we tested the separate and combined effects of stress and variability by exposing corallines from the same sites to either ambient (Amb: pH 8.04) or acidified (OA: pH 7.70) stable conditions or variable (Var: pH 7.80-8.10) or acidified variable (OA-Var: pH 7.45-7.75) conditions. There was a negative effect of all pH treatments on Lithophyllum sp. calcification rates relative to the control, with lower calcification rates in corallines from the extreme site than from the moderate site in each treatment, indicative of a legacy effect of site origin on subsequent response to laboratory treatment. Our study provides ecologically relevant context to understanding the nuanced effects of OA on crustose coralline algae, and illustrates how local environmental regimes may influence the effects of global change.
    Keywords: Alkalinity, total; Alkalinity, total, standard error; Aragonite saturation state; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (〈20 L); Calcification/Dissolution; Calcification rate of calcium carbonate; Calcite saturation state; Calcite saturation state, standard error; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard error; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cayo_Roldan; Coast and continental shelf; Event label; EXP; Experiment; Field experiment; Flow rate; Flow rate, standard error; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Hospital_Point; Identification; Irradiance; Irradiance, standard error; Laboratory experiment; Lithophyllum sp.; Macroalgae; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Partial pressure of carbon dioxide (water) at sea surface temperature (wet air), standard error; pH; pH, standard error; Plantae; Potentiometric; Potentiometric titration; Replicate; Rhodophyta; Salinity; Salinity, standard error; Single species; Site; Species; Temperature, water; Temperature, water, standard error; Time point, descriptive; Treatment; Tropical; Type
    Type: Dataset
    Format: text/tab-separated-values, 15767 data points
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  • 2
    ISSN: 1523-5378
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background.  Helicobacter pylori infection is usually acquired during childhood and is a known risk factor for the development of gastric malignancies in adulthood. It has been reported that early age at first infection may determine a neoplastic outcome in adults. The purpose of this study was to determine the prevalence of Helicobacter pylori infection in children residing in areas with high (Pasto) and low risk (Tumaco) of gastric cancer in Colombia to evaluate whether differences in the age of acquisition of H. pylori infection were present in the two populations.Materials and Methods.  The study sample was based on a census taken in 1999. Using the 13C-urea breath test, we compared the prevalence of H. pylori infection among children aged 1–6 years.Results.  Among 345 children in Pasto, 206 (59.7%) were H. pylori-positive, compared with 188 (58.6%) among 321 children in Tumaco. The two populations share a common pattern of very early age at infection and marked increase in prevalence during the first 4 years of life. No differences in any one year were observed when comparing the two groups.Conclusions.  The prevalence of infection was similarly high and increased with age in both populations. In these populations the age of acquisition of H. pylori after 1 year of age does not appear to be a primary factor responsible for the differences in the rates of gastric cancer incidence in adults. Previous findings in adults showed lower prevalence of the most virulent genotypes in Tumaco compared to Pasto, and bacterial virulence may play a key role in determining cancer outcome.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 375 (1995), S. 542-543 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - The origin and early domestication of cacao (Theobroma cacao ssp. cacao L.) remains an elusive issue as a result of uncertainty about the historical distribution of wild populations, ancient cultivations, human-mediated dispersion and continued crossing ...
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2019-02-01
    Description: Mesoscale eddies are important, frequent, and persistent features of the circulation in the eastern South Pacific (ESP) Ocean, transporting physical, chemical and biological properties from the productive shelves to the open ocean. Some of these eddies exhibit subsurface hypoxic or suboxic conditions and may serve as important hotspots for nitrogen loss, but little is known about oxygen consumption rates and nitrogen transformation processes associated with these eddies. In the austral fall of 2011, during the Tara Oceans expedition, an intrathermocline, anticyclonic, mesoscale eddy with a suboxic (〈 2 µmol kg−1 of O2), subsurface layer (200–400 m) was detected  ∼  900 km off the Chilean shore (30° S, 81° W). The core of the eddy's suboxic layer had a temperature-salinity signature characteristic of Equatorial Subsurface Water (ESSW) that at this latitude is normally restricted to an area near the coast. Measurements of nitrogen species within the eddy revealed undersaturation (below 44 %) of nitrous oxide (N2O) and nitrite accumulation (〉 0.5 µM), suggesting that active denitrification occurred in this water mass. Using satellite altimetry, we were able to track the eddy back to its region of formation on the coast of central Chile (36.1° S, 74.6° W). Field studies conducted in Chilean shelf waters close to the time of eddy formation provided estimates of initial O2 and N2O concentrations of the ESSW source water in the eddy. By the time of its offshore sighting, concentrations of both O2 and N2O in the subsurface oxygen minimum zone (OMZ) of the eddy were lower than concentrations in surrounding water and “source water” on the shelf, indicating that these chemical species were consumed as the eddy moved offshore. Estimates of apparent oxygen utilization rates at the OMZ of the eddy ranged from 0.29 to 44 nmol L−1 d−1 and the rate of N2O consumption was 3.92 nmol L−1 d−1. These results show that mesoscale eddies affect open-ocean biogeochemistry in the ESP not only by transporting physical and chemical properties from the coast to the ocean interior but also during advection, local biological consumption of oxygen within an eddy further generates conditions favorable to denitrification and loss of fixed nitrogen from the system.
    Type: Article , PeerReviewed
    Format: text
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  • 5
    Publication Date: 2019-09-24
    Description: While observations suggest a long-term expansion of the Oxygen Minimum Zone (OMZ) in the South Eastern Pacific (SEP), it also exhibits a large interannual to decadal variability in its upper and lower limits. The uncertainty of the fate of the SEP OMZ in a warmer climate as simulated by Earth system models also questions to which extent natural variability in the OMZ can obscure the detection of externally forced trends. Here we analyze long-term simulations from a hierarchy of models of the OMZ off Peru and Chile and show that a significant share of the variability is not linearly related to climate modes (including ENSO), suggesting that it originates from internal dynamics associated to both local non-linear physical and biogeochemical processes. Still the OMZ volume tends to shrink during strong Eastern Pacific El Niño while it expands during La Niña and Central Pacific El Niño events. It is shown in particular that La Niña and strong El Niño events significantly modulate the OMZ volume through the transport of water masses of equatorial origin by the Peru/Chile undercurrent and the propagation of extra-tropical Rossby waves. Implications of our results are discussed in terms of the challenge for developing an Eastern Pacific observing system in the frame of the TPOS2020 program, considering the time of emergence for climate-trend detection above background variability.
    Type: Conference or Workshop Item , NonPeerReviewed
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  • 6
    Publication Date: 2022-01-31
    Description: Subtropical gyres are the oceanic regions where plastic litter accumulates over long timescales, exposing surrounding oceanic islands to plastic contamination, with potentially severe consequences on marine life. Islands’ exposure to such contaminants, littered over long distances in marine or terrestrial habitats, is due to the ocean currents that can transport plastic over long ranges. Here, this issue is addressed for the Easter Island ecoregion (EIE). High-resolution ocean circulation models are used with a Lagrangian particle-tracking tool to identify the connectivity patterns of the EIE with industrial fishing areas and coastline regions of the Pacific basin. Connectivity patterns for “virtual” particles either floating (such as buoyant macroplastics) or neutrally-buoyant (smaller microplastics) are investigated. We find that the South American shoreline between 20°S and 40°S, and the fishing zone within international waters off Peru (20°S, 80°W) are associated with the highest probability for debris to reach the EIE, with transit times under 2 years. These regions coincide with the most-densely populated coastal region of Chile and the most-intensely fished region in the South Pacific. The findings offer potential for mitigating plastic contamination reaching the EIE through better upstream waste management. Results also highlight the need for international action plans on this important issue.
    Type: Article , PeerReviewed
    Format: text
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  • 7
    Publication Date: 2024-02-07
    Description: The abundance and distribution of plastic debris at the sea surface shows considerable variability over different spatial scales. Some of the oceanographic processes at small (〈1 km) and submeso (1–10 km) scales manifest themselves as slicks at the sea surface, which might have the potential to concentrate organisms and particles (such as positively buoyant plastics), putting species that feed in these areas at risk of ingesting plastics. Slicks can be filaments, lines, meanders, or patches, which are lighter in color and smoother in surface roughness compared to the surrounding area. Here we tested the hypothesis that passive particles (including plastics) and organisms are aggregated in the surface waters within these slicks. According to their main features (orientation to coast and/or wind), the studied slicks were most likely generated by oceanographic processes such as topographically controlled fronts, other types of fronts and internal waves. Neuston samples were collected from the sea surface inside and outside of slicks (n = 11 sites with slicks) in the coastal waters of Rapa Nui (Easter Island) during two campaigns in austral summer (January 2018) and autumn (April 2019). In general, passive particles, including plastics, exuviae, eggs and foraminiferans, were found more frequently inside than outside the slicks. In some cases, motile zooplankton organisms such as chaetognaths, vertically migrating crustaceans and early developmental stages (EDS) of fish were also more common within the slicks. In addition, a positive relationship was found between plastics and planktonic organisms such as foraminiferans, snails and jellyfish (e.g., Velella velella), although a strong correlation was also found with fish EDS and chaetognaths. These results suggest that surface slicks are areas of aggregation for both passive particles and active organisms, thus playing an important ecological role in food retention and particle concentration where the risk of plastic ingestion by fish and seabirds is enhanced
    Type: Article , PeerReviewed
    Format: text
    Format: text
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  • 8
    Publication Date: 2021-05-19
    Description: The Canary Current Large Marine Ecosystem shelf has the typical size and composition, of passive continental margins. In general, it has a mean width between 40-50 km, with exceptions like Bank D´Arguin or Dakar. The maximum age of the sedimentary rocks is 200 Ma. The geomorphological variations are the result of the sedimentary contributions associated to the river basins, which also influence the genesis and presence of canyons in the shelf and slope. These canyons are the main geomorphological features in the region. Seamounts, salt domes, pockmarcks and gravitational processes like debris flows are also observed. The tectonic processes are generally extensive, but have a small influence. It is remarkable the presence of a coral reef with more than 400 km of length in the shallowest Mauritania slope. The geomorphological studies in the intraplate volcanic islands (Canary Islands and Cape Verde), confirm the presence of developed shelves in the older islands, not observed in the younger ones. There are gravitational slides and canyons in all the islands. The region was divided in 4 areas: Morocco–Western Sahara; Mauritania; Canary Islands; and Senegal –Gambia –Guinea–Bissau – Guinea–Cape Verde. Within each of these areas, different geomorphological and geological domains are described.
    Description: Published
    Keywords: Passive continental margin ; Geologic domains ; Geomorphologic features ; Geologic processes ; Intraplate volcanic islands ; CCLME
    Repository Name: AquaDocs
    Type: Report Section , Refereed
    Format: pp. 23-38
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