15 research outputs found
Competition for food between the introduced polychaete Marenzelleria viridis (Verrill) and the native amphipod Monoporeia affinis Lindström in the Baltic
Abstract Since 1985 the spionid polychaete Marenzelleria viridis (Verrill) has invaded large parts of the Baltic Sea. In deeper softbottom habitats (>10 m) a marked long-term decrease of the native amphipod Monoporeia affinis has been noted and is presently associated with the establishment of the polychaete. One plausible explanation is that the polychaetes and the amphipods are competing for food resources as both are deposit feeding animals and likely to share similar food resources. Interspecific competition for food between the polychaete and the amphipod was studied in a laboratory experiment. Two year classes (0y+,1y+) of the amphipods were kept at various densities, with and without added food resources, with and without the polychaete, in microcosms with sediment and continuous supply of cooled water for 2 months. The polychaetes did not have any effect on mortality in the amphipods. 4-way ANOVA showed that food addition, density of amphipods and presence of the polychaete had a significant effect on the growth of amphipods of different age classes. 1y+ amphipods showed increased growth with added food and this increase was density-dependent in the absence of the polychaetes but not in their presence. The polychaetes reduced the growth of 1y+ amphipods at natural densities (2000 ind m À 2 ) by 60%, but had no clear effects on the growth of juveniles. It is concluded that lower amphipod growth in the presence of M. viridis was caused by competition for food and is likely to affect the population of M. affinis in deep soft-bottom habitats of the northern Baltic Sea.
Income Inequality Developments in the Great Recession
The Great Recession has increased concerns over the fairness of the distribution of wealth and income in many societies. Using data on eight advanced economies (Germany, Greece, Ireland, Italy, Slovakia, Spain, the United Kingdom, and United States) between 2007 and 2010, I show how the Great Recession affected income inequality in different countries and how families and the state tried to mitigate its impact - through redistributing income within households and through the tax and benefit system. In most countries redistribution within household, through the social safety net and through direct taxes has been largely successful in offsetting the effect on income inequality of increased earnings inequality caused by the rise in unemployment in this pre-austerity period. I discuss some policy lessons that emerge from the varying experiences of different countries
Health related quality of life and perception of deformity in patients with adolescent idiopathic scoliosis
BACKGROUND: Quality of life and cosmethic appearance have gained importance as outcomes in AIS treatment. Improving aesthetic appearance and quality of life are defined as the primary aims of scoliosis treatment by health professionals. Studies that assess and compare the different treatment results in the field of quality of life and cosmethics are some what limited
High-resolution alkenone sea surface temperature variability on the North Icelandic Shelf: implications for Nordic Seas palaeoclimatic development during the Holocene
The palaeoceanography of the northern Icelandic Shelf for the Holocene period was reconstructed from alkenone indices measured in core JR51-GC35. This contains a continuous record of Holocene sedimentation spanning 0 10.2 cal. kyr BP with a resolution of ~ 20 yr/cm. We have identified a general Holocene cooling trend that has superimposed millennial-scale oscillations of >2°C. Their timing is in close agreement with the timing of glacier advances in northern Iceland. For the later half of the Holocene, the alkenone-sea surface temperature (SST) record from JR51-GC35 correlates with proxy data for the strength of NADW formation recorded in cores south of Iceland. This is interpreted as evidence of a close connection existing between north Icelandic sea surface temperatures and the North Atlantic meridonal overturning circulation. The timing of the millennial-scale SST variability in our core off North Iceland is found to be out of phase, or anti-phased, with the SST variability of a record in the eastern Nordic Seas (MD952011). This suggests that the evolution of Holocene climate in the Nordic Seas was more complex than previously proposed; and it is likely to be caused by differential responses of the Irminger and Norwegian Currents and modulated by changes in atmospheric circulation analogous to the North Atlantic Oscillation