Usnea antarctica, an important Antarctic lichen, is vulnerable to aspects of regional environmental change

Studies of cryptogam responses to climate change in the polar regions are scarce because these slow-growing organisms require long-term monitoring studies. Here, we analyse the response of a lichen and moss community to 10 years of passive environmental manipulation using open-top chambers (OTCs) in the maritime Antarctic region. Cover of the dominant lichen Usnea antarctica declined by 71 % in the OTCs. However, less dominant lichen species showed no significant responses except for an increase in Ochrolechia frigida, which typically covered dying lichen and moss vegetation. There were no detectable responses in the moss or associated micro-arthropod communities to the influence of the OTCs. Based on calculated respiration rates, we hypothesise that the decline of U. antarctica was most likely caused by increased net winter respiration rates (11 %), driven by the higher temperatures and lower light levels experienced inside the OTCs as a result of greater snow accumulation. During summer, U. antarctica appears unable to compensate for this increased carbon loss, leading to a negative carbon balance on an annual basis, and the lichen therefore appears to be vulnerable to such climate change simulations. These findings indicate that U. antarctica dominated fell-fields may change dramatically if current environmental change trends continue in the maritime Antarctic, especially if associated with increases in winter snow depth or duration

Skills Labs - Deliverable 2.1.a: Casusidee Estuarine systems: the Scheldt

Tysmans, D., Lansu, A., Löhr, A., Landsman, N., Huiskes, A., & Verkruysse, B. (2008). Skills Labs - Deliverable 2.1.a: Casusidee Estuarine systems: the Scheldt.Volgens de Emergo-methode uitgewerkt casusidee van casus Estuarine systems: the Scheldt binnen het project Skills Labs.SURFFoundatio

The changing form of Antarctic biodiversity

Antarctic biodiversity is much more extensive, ecologically diverse and biogeographically structured than previously thought. Understanding of how this diversity is distributed in marine and terrestrial systems, the mechanisms underlying its spatial variation, and the significance of the microbiota is growing rapidly. Broadly recognizable drivers of diversity variation include energy availability and historical refugia. The impacts of local human activities and global environmental change nonetheless pose challenges to the current and future understanding of Antarctic biodiversity. Life in the Antarctic and the Southern Ocean is surprisingly rich, and as much at risk from environmental change as it is elsewher

Basic Science Considerations in Primary Total Hip Replacement Arthroplasty

Total Hip Replacement is one of the most common operations performed in the developed world today. An increasingly ageing population means that the numbers of people undergoing this operation is set to rise. There are a numerous number of prosthesis on the market and it is often difficult to choose between them. It is therefore necessary to have a good understanding of the basic scientific principles in Total Hip Replacement and the evidence base underpinning them. This paper reviews the relevant anatomical and biomechanical principles in THA. It goes on to elaborate on the structural properties of materials used in modern implants and looks at the evidence base for different types of fixation including cemented and uncemented components. Modern bearing surfaces are discussed in addition to the scientific basis of various surface engineering modifications in THA prostheses. The basic science considerations in component alignment and abductor tension are also discussed. A brief discussion on modular and custom designs of THR is also included. This article reviews basic science concepts and the rationale underpinning the use of the femoral and acetabular component in total hip replacement

Terrestrial research during the fourth International Polar Year

Huiskes, A., M.J.J.E. Loonen & J. Rozema(2016) Terrestrisch onderzoek tijdens het vierde Internationale Pooljaar. In: Buma, A.G.J., A.J.M. Scheepstra & R. Bintanja (eds). Door de kou bevangen. Vijftig jaar Nederlands onderzoek in de poolgebieden. Uitgeverij MaRiSuDa, Lelystad: 182-185Huiskes, A., M.J.J.E. Loonen & J. Rozema(2016) Terrestrisch onderzoek tijdens het vierde Internationale Pooljaar. In: Buma, A.G.J., A.J.M. Scheepstra & R. Bintanja (eds). Door de kou bevangen. Vijftig jaar Nederlands onderzoek in de poolgebieden. Uitgeverij MaRiSuDa, Lelystad: 182-185

Soil characteristics and decomposition of organic matter on Anchorage, Signy and Falkland Islands

Antarctic terrestrial ecosystems have poorly developed soils and currently experience one of the greatest rates of climate warming on the globe. We investigated the responsiveness of organic matter decomposition in Maritime Antarctic terrestrial ecosystems to climate change, using two study sites in the Antarctic Peninsula region (Anchorage Island, 67°S; Signy Island, 61°S), and contrasted the responses found with those at the cool temperate Falkland Islands (52°S). Our approach consisted of two complementary methods: (1) Laboratory measurements of decomposition at different temperatures (2, 6 and 10 °C) of plant material and soil organic matter from all three locations. (2) Field measurements at all three locations on the decomposition of soil organic matter, plant material and cellulose, both under natural conditions and under experimental warming (about 0.8 °C) achieved using open top chambers. Higher temperatures led to higher organic matter breakdown in the laboratory studies, indicating that decomposition in Maritime Antarctic terrestrial ecosystems is likely to increase with increasing soil temperatures. However, both laboratory and field studies showed that decomposition was more strongly influenced by local substratum characteristics (especially soil N availability) and plant functional type composition than by large-scale temperature differences. The very small responsiveness of organic matter decomposition in the field (experimental temperature increase <1 °C) compared with the laboratory (experimental increases of 4 or 8 °C) shows that substantial warming is required before significant effects can be detected