95 research outputs found
Will ocean acidification affect marine microbes?
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in The ISME Journal 5 (2011): 1-7, doi:10.1038/ismej.2010.79.The pH of the surface ocean is changing as a result of increases in
atmospheric carbon dioxide (CO2) and there are concerns about potential
impacts of lower pH and associated alterations in seawater carbonate
chemistry on the biogeochemical processes in the ocean. However, it is
important to place these changes within the context of pH in the present day
ocean, which is not constant; it varies systematically with season, depth and
along productivity gradients. Yet this natural variability in pH has rarely been
considered in assessments of the effect of ocean acidification on marine
microbes. Surface pH can change as a consequence of microbial utilisation
and production of carbon dioxide, and to a lesser extent other microbiallymediated
processes such as nitrification. Useful comparisons can be made
with microbes in other aquatic environments that readily accommodate very
large and rapid pH change. For example, in many freshwater lakes, pH changes
that are orders of magnitude greater than those projected for the 22nd century
oceans can occur over periods of hours. Marine and freshwater assemblages
have always experienced variable pH conditions. Therefore, an appropriate null
hypothesis may be, until evidence is obtained to the contrary, that major
biogeochemical processes in the oceans other than calcification will not be
fundamentally different under future higher CO2 / lower pH conditions.Funding from the Gordon and Betty Moore Foundation, and logistical support from
the Plymouth Marine Laboratory and the Center for Microbial Oceanography:
Research and Education (National Science Foundation grant EF-0424599) are
gratefully acknowledged
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Food for pollinators: quantifying the nectar and pollen resources of urban flower meadows
Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many ‘pollinator-friendly’ seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data exist. Our approach should inform the design of new seed mixes to ensure continuity in floral resource availability throughout the year, and to identify suitable species to fill resource gaps in established mixes
Physic nut plants present high mycorrhizal dependency under conditions of low phosphate availability
The central nervous system transcriptome of the weakly electric brown ghost knifefish (Apteronotus leptorhynchus): de novo assembly, annotation, and proteomics validation
Auditory event-related potentials
Auditory event related potentials are electric potentials (AERP, AEP) and magnetic fields (AEF) generated by the synchronous activity of large neural populations in the brain, which are time-locked to some actual or expected sound event
Interpretation and physiological significance of diastolic coronary artery pressure-flow relationships in the canine coronary bed.
Ventral mandibulectomy for removal of oral tumours in the dog: Surgical technique and results in 19 cases
Valvular-ventricular interaction: importance of the mitral apparatus in canine left ventricular systolic performance.
Effects of barium-induced cardiac contraction on large- and small-vessel intramyocardial blood volume.
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