Long term effects of warming and ocean acidification are modified by seasonal variation in species responses and environmental conditions

Warming of sea surface temperatures and alteration of ocean chemistry associated with anthropogenic increases in atmospheric carbon dioxide will have profound consequences for a broad range of species, but the potential for seasonal variation to modify species and ecosystem responses to these stressors has received little attention. Here, using the longest experiment to date (542 days), we investigate how the interactive effects of warming and ocean acidification affect the growth, behaviour and associated levels of ecosystem functioning (nutrient release) for a functionally important non-calcifying intertidal polychaete (Alitta virens) under seasonally changing conditions. We find that the effects of warming, ocean acidification and their interactions are not detectable in the short term, but manifest over time through changes in growth, bioturbation and bioirrigation behaviour that, in turn, affect nutrient generation. These changes are intimately linked to species responses to seasonal variations in environmental conditions (temperature and photoperiod) that, depending upon timing, can either exacerbate or buffer the long-term directional effects of climatic forcing. Taken together, our observations caution against over emphasizing the conclusions from short-term experiments and highlight the necessity to consider the temporal expression of complex system dynamics established over appropriate timescales when forecasting the likely ecological consequences of climatic forcing

Ocean acidification and climate change: advances in ecology and evolution

Atmospheric CO2 concentration [CO2] has increased from a pre-industrial level of approximately 280 ppm to approximately 385 ppm, with further increases (700–1000 ppm) anticipated by the end of the twenty-first century [1]. Over the past three decades, changes in [CO2] have increased global average temperatures (approx. 0.2°C decade?1 [2]), with much of the additional energy absorbed by the world's oceans causing a 0.8°C rise in sea surface temperature over the past century. The rapid uptake of heat energy and CO2 by the ocean results in a series of concomitant changes in seawater carbonate chemistry, including reductions in pH and carbonate saturation state, as well as increases in dissolved CO2 and bicarbonate ions [3]: a phenomenon defined as ocean acidification. Time-series and survey measurements [4–6] over the past 20 years have shown that surface ocean pH has reduced by 0.1 pH unit relative to pre-industrial levels, equating to a 26% increase in ocean acidity [3]. Reductions of 0.4–0.5 pH units are projected to occur by the end of the twenty-first century [1] and, while atmospheric [CO2] has consistently fluctuated by 100–200 ppm over the past 800 000 years [7], the recent and anticipated rates of change are unprecedented [8]

Coastal Biodiversity and Ecosystem Service Sustainability (CBESS) total organic carbon in mudflat and saltmarsh habitats

The dataset details organic carbon content of sediments across 6 intertidal sites in the winter and summer of 2013. The data provide a quantitative measure of the organic carbon present within surface sediments (up to a depth of 2 cm). Three sites were located in Essex, South East England and the other 3 in Morecambe Bay, North West England. Each site consisted of a saltmarsh habitat and adjacent mudflat habitat. 22 sampling quadrats were placed in each habitat covering 4 spatial scales. 3 replicate samples of surface sediment were collected at each quadrat. They were then processed for organic carbon content using the Loss on Ignition method (detailed below) Values are expressed as a percentage of the total sample collected. This data was collected as part of Coastal Biodiversity and Ecosystem Service Sustainability (CBESS): NE/J015644/1. The project was funded with support from the Biodiversity and Ecosystem Service Sustainability (BESS) programme. BESS is a six-year programme (2011-2017) funded by the UK Natural Environment Research Council (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC) as part of the UK&#39;s Living with Environmental Change (LWEC) programme.,The location of the sample sites was determined by randomly allocated quadrats. Twenty two 1 x 1 m quadrats were randomly allocated to each mudflat and saltmarsh site using R (R Development Core Team, 2014) to specify four different spatial scales (A = 1 quadrat only, B = 3 quadrats at 1 m to 10 m apart, C = 6 quadrats at 10 m to 100 m apart, D = 12 quadrats at 100 m to 1000 m or site maximum). Mudflats: surface scrapes of sediment were taken. Saltmarsh: sediment was cut from 2cm below the surface. All samples were frozen at minus 20 degrees and then analysed using standard loss on ignition (LOI) technique, full details of which can be found here: http://www.geog.cam.ac.uk/facilities/laboratories/techniques/loi.html,</span

Riparian Deforestation Affects the Structural Dynamics of Headwater Streams in Southern Brazilian Amazonia

Comparative studies of streams with altered versus conserved riparian zones are important to evaluate the degree of alterations caused by inappropriate use of these streams’ vital buffer zones. The aim of this study was to determine the impact of riparian deforestation on the habitat structure of southern Brazilian Amazonian headwater streams, as well as to provide elements for impact assessment and the monitoring of these water bodies. We selected ten sites and two headwater streams at each site; one stream was located in an area with preserved riparian vegetation (pristine streams) and the other stream in a deforested riparian zone (altered streams). Stretches of these streams were analyzed across hydrological periods (dry period, beginning of the rainy period, and end of the rainy period) for hydro-morphological aspects, water physical-chemical variables, and habitat integrity (proportion of forestation in buffer zones and habitat integrity index). Compared to pristine streams in all the hydrological periods analyzed, altered streams presented lower oxygen concentration (~1.0 mg/L), an increase of 1 °C in water temperature, and less organic material availability. We found that riparian deforestation affects habitat structure variability among hydrological periods, making them more homogeneous. Therefore, beyond the necessary broadening of the spatial scale of studies in this region, monitoring these understudied headwater stream environments is also crucial for determining the magnitude of deforestation effects on these vulnerable aquatic ecosystems. © Monica Elisa Bleich, Amanda Frederico Mortati, Thiago André and Maria Teresa Fernandez Piedade

Evidence that Dot-dependent and -independent factors isolate the Legionella pneumophila phagosome from the endocytic network in mouse macrophages

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74415/1/j.1462-5822.2001.00093.x.pd