scholarly journals Investigation of the abundance, distribution and composition of microplastics at coastal upwelling sites in the Atlantic Ocean

2016 ◽  
Author(s):  
La Daana K Kanhai ◽  
Rick Officer ◽  
Ian O'Connor ◽  
Richard C Thompson
Keyword(s):  
Atlantic Ocean ◽  
Surface Waters ◽  
Primary Productivity ◽  
Null Hypothesis ◽  
Latitudinal Gradient ◽  
Coastal Upwelling ◽  
Abundance Distribution ◽  
Significant Difference ◽  
Benguela Upwelling ◽  
Canary Upwelling

Microplastics are an issue of international concern due to the fact that these substances may potentially threaten biota by (i) causing physical harm, (ii) transporting persistent, bioaccumulating and toxic (PBT) substances and, (iii) leaching plastic additives. Within the world’s oceans, areas which experience coastal upwelling are biota rich due to their high levels of primary productivity. The assessment of microplastic presence in areas which experience coastal upwelling is vital as it will indicate whether microplastics are an issue of concern in areas which support key biological resources. The null hypothesis of the present study is that microplastic abundance will be lower in areas where there is upwelling. As such, the present study aims to investigate whether microplastic abundance in upwelled areas in the Atlantic Ocean is significantly different from non-upwelled areas. Based on an opportunistic voyage aboard the RV Polarstern, microplastics will be sampled in sub-surface waters along a diverse latitudinal gradient in the Atlantic Ocean i.e. from Bremerhaven (Germany) to Cape Town (South Africa). Based on the proposed route, it will be possible to determine microplastic levels at two areas of coastal upwelling in the Atlantic Ocean (i) Canary Upwelling Ecosystem (CUE) and (ii) Benguela Upwelling Ecosystem (BUE). The results will then be analysed to determine whether there was a statistically significant difference between ‘upwelled areas’ and ‘non-upwelled areas’.

scholarly journals Investigation of the abundance, distribution and composition of microplastics at coastal upwelling sites in the Atlantic Ocean

2016 ◽  
Author(s):  
La Daana K Kanhai ◽  
Rick Officer ◽  
Ian O'Connor ◽  
Richard C Thompson
Keyword(s):  
Atlantic Ocean ◽  
Surface Waters ◽  
Primary Productivity ◽  
Null Hypothesis ◽  
Latitudinal Gradient ◽  
Coastal Upwelling ◽  
Abundance Distribution ◽  
Significant Difference ◽  
Benguela Upwelling ◽  
Canary Upwelling

Microplastics are an issue of international concern due to the fact that these substances may potentially threaten biota by (i) causing physical harm, (ii) transporting persistent, bioaccumulating and toxic (PBT) substances and, (iii) leaching plastic additives. Within the world’s oceans, areas which experience coastal upwelling are biota rich due to their high levels of primary productivity. The assessment of microplastic presence in areas which experience coastal upwelling is vital as it will indicate whether microplastics are an issue of concern in areas which support key biological resources. The null hypothesis of the present study is that microplastic abundance will be lower in areas where there is upwelling. As such, the present study aims to investigate whether microplastic abundance in upwelled areas in the Atlantic Ocean is significantly different from non-upwelled areas. Based on an opportunistic voyage aboard the RV Polarstern, microplastics will be sampled in sub-surface waters along a diverse latitudinal gradient in the Atlantic Ocean i.e. from Bremerhaven (Germany) to Cape Town (South Africa). Based on the proposed route, it will be possible to determine microplastic levels at two areas of coastal upwelling in the Atlantic Ocean (i) Canary Upwelling Ecosystem (CUE) and (ii) Benguela Upwelling Ecosystem (BUE). The results will then be analysed to determine whether there was a statistically significant difference between ‘upwelled areas’ and ‘non-upwelled areas’.

scholarly journals Microplastic abundance, distribution and composition along a latitudinal gradient in the Atlantic Ocean

2017 ◽  
Vol 115 (1-2) ◽  
pp. 307-314 ◽  
Author(s):  
La Daana K. Kanhai ◽  
Rick Officer ◽  
Olga Lyashevska ◽  
Richard C. Thompson ◽  
Ian O'Connor
Keyword(s):  
Atlantic Ocean ◽  
Latitudinal Gradient ◽  
Abundance Distribution

Southeast tropical Atlantic changing from subtropical to tropical conditions

2021 ◽  
Author(s):  
Marisa Roch ◽  
Peter Brandt ◽  
Sunke Schmidtko
Keyword(s):  
Wind Stress ◽  
Surface Waters ◽  
Primary Productivity ◽  
Coastal Upwelling ◽  
Ocean Dynamics ◽  
Upper Ocean ◽  
Tropical Atlantic ◽  
Ocean Stratification ◽  
Tropical Conditions ◽  
Stress Changes

<div> <p><span>A warming and freshening trend of the mixed layer in the upper southeast tropical Atlantic Ocean (SETA) is observed by the Argo observation array during the time period of 2006 to 2019. Thus, the ocean surface density is reducing. This has an impact on the upper-ocean stratification which intensified by more than 30 % in the SETA region since 2006. The initial typical subtropical stratification with a salinity maximum at the surface is shifted to more tropical conditions characterized by warmer and fresher surface waters and a subsurface salinity maximum. </span></p> </div><div> <p><span>A more detailed analysis of isopycnals shows a continuous upward displacement of isopycnal surfaces suggesting that wind stress curl-driven upwelling has to play an essential role. Therefore, ASCAT wind stress changes are examined, revealing that increased open ocean wind curl-driven upwelling but also partly counteracting reduced coastal upwelling due to weakened alongshore southerly winds are present. Changing alongshore winds might be a reason why tropical surface waters spread further southward reaching more into the SETA region. Besides, atmospheric fluxes could further impact upper ocean characteristics. </span></p> </div><div> <p><span>Changes in the upper-ocean stratification matter as they affect not only physical ocean dynamics such as ocean ventilation processes but also biogeochemical and ecological activities such as nutrient fluxes and fisheries. Nevertheless, the consequences of increased stratification for upwelling regions are not yet fully understood. The SETA upwelling system is a key region for enhanced nutrient supply to the euphotic zone and hence, a core nutrient source for high coastal primary productivity. </span></p> </div><p>We aim to assess the recent change of upper-ocean stratification towards tropical conditions at the sea surface in the SETA region and explore its driving mechanisms as well as possible consequences for the primary productivity and fisheries off Angola and Namibia, in order to improve our understanding of what is happening as a result of intensified upper-ocean stratification in upwelling regions.</p>

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

scholarly journals Sinking rates and ballast composition of particles in the Atlantic Ocean: implications for the organic carbon fluxes to the deep ocean

2009 ◽  
Vol 6 (1) ◽  
pp. 85-102 ◽  
Author(s):  
G. Fischer ◽  
G. Karakaş
Keyword(s):  
Organic Carbon ◽  
Atlantic Ocean ◽  
Sediment Trap ◽  
Carbon Flux ◽  
Coastal Upwelling ◽  
Production Systems ◽  
Deep Ocean ◽  
Biogeochemical Model ◽  
Carbonate Content ◽  
Organic Carbon Flux

Abstract. The flux of materials to the deep sea is dominated by larger, organic-rich particles with sinking rates varying between a few meters and several hundred meters per day. Mineral ballast may regulate the transfer of organic matter and other components by determining the sinking rates, e.g. via particle density. We calculated particle sinking rates from mass flux patterns and alkenone measurements applying the results of sediment trap experiments from the Atlantic Ocean. We have indication for higher particle sinking rates in carbonate-dominated production systems when considering both regional and seasonal data. During a summer coccolithophorid bloom in the Cape Blanc coastal upwelling off Mauritania, particle sinking rates reached almost 570 m per day, most probably due the fast sedimentation of densely packed zooplankton fecal pellets, which transport high amounts of organic carbon associated with coccoliths to the deep ocean despite rather low production. During the recurring winter-spring blooms off NW Africa and in opal-rich production systems of the Southern Ocean, sinking rates of larger particles, most probably diatom aggregates, showed a tendency to lower values. However, there is no straightforward relationship between carbonate content and particle sinking rates. This could be due to the unknown composition of carbonate and/or the influence of particle size and shape on sinking rates. It also remains noticeable that the highest sinking rates occurred in dust-rich ocean regions off NW Africa, but this issue deserves further detailed field and laboratory investigations. We obtained increasing sinking rates with depth. By using a seven-compartment biogeochemical model, it was shown that the deep ocean organic carbon flux at a mesotrophic sediment trap site off Cape Blanc can be captured fairly well using seasonal variable particle sinking rates. Our model provides a total organic carbon flux of 0.29 Tg per year down to 3000 m off the NW African upwelling region between 5 and 35° N. Simple parameterisations of remineralisation and sinking rates in such models, however, limit their capability in reproducing the flux variation in the water column.

scholarly journals Facial Profile Shape, Malocclusion and Palatal Morphology in Malay Obstructive Sleep Apnea Patients

2010 ◽  
Vol 80 (1) ◽  
pp. 37-42 ◽  
Author(s):  
S. M. Banabilh ◽  
A. R. Samsudin ◽  
A. H. Suzina ◽  
Sidek Dinsuhaimi
Keyword(s):  
Obstructive Sleep Apnea ◽  
Null Hypothesis ◽  
Control Group ◽  
Class Ii Malocclusion ◽  
Chi Square ◽  
Facial Profile ◽  
Obstructive Sleep ◽  
Significant Difference ◽  
Chi Square Test ◽  
The Mean

Abstract Objective: To test the null hypothesis that there is no difference in facial profile shape, malocclusion class, or palatal morphology in Malay adults with and without obstructive sleep apnea (OSA). Materials and Methods: Subjects were 120 adult Malays aged 18 to 65 years (mean ± standard deviation [SD], 33.2 ± 13.31) divided into two groups of 60. Both groups underwent clinical examination and limited channel polysomnography (PSG). The mean OSA and control values were subjected to t-test and the chi square test. Results: Physical examination showed that 61.7% of the OSA patients were obese, and 41.7% of those obese patients had severe OSA. The mean body mass index (BMI) was significantly greater for the OSA group (33.2 kg/m2 ± 6.5) than for the control group (22.7 kg/m2 ± 3.5; P < .001). The mean neck size and systolic blood pressure were greater for the OSA group (43.6 cm ± 6.02; 129.1 mm Hg ± 17.55) than for the control group (35.6 cm ± 3.52; 114.1 mm Hg ± 13.67; P < .001). Clinical examination showed that the most frequent findings among OSA groups when compared with the control group were convex profiles (71.7%), Class II malocclusion (51.7%), and V palatal shape (53.3%), respectively; the chi square test revealed a significant difference in terms of facial profile and malocclusion class (P < .05), but no significant difference in palatal shape was found. Conclusion: The null hypothesis is rejected. A convex facial profile and Class II malocclusion were significantly more common in the OSA group. The V palatal shape was a frequent finding in the OSA group.

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