Marine phytoplankton in a high CO2 world

Marine phytoplankton is responsible for ~50% of global primary productivity, it supports the oceanic food web and affects biogeochemical cycles. I participated in a large mesocosm experiment that observed altered community structure and carbon drawdown in response to increased CO2. There was a 27% reduction in community primary production at the peak of an Emiliania huxleyi-dominated bloom in mesocosms initially at 760 ppm CO2 compared to present day pCO2. There were changes in community structure but not dominance; Synechococcus and large pico-eukaryote abundances were reduced by ~60%, E. huxleyi was reduced by ~50%. A number of E. huxleyi strains persisted throughout the experiment in both treatments and no malformation or significant change in lith size occurred at increased CO2. In a second field experiment in the oligotrophic ocean off the Canary Islands, 760 ppm pCO2 did not change community structure or cell division rates of Synechococcus, Prochlorococcus or pico-eukaryotes.In laboratory experiments, I maintained the diatom, Thalassiosira pseudonana CCMP1335 at 760 ppm and present day pCO2 for ~100 generations in gas equilibrated continuous cultures – one of the longest experiments that has been attempted to investigate the effect of increased CO2 on marine phytoplankton. No clear evidence of adaptation or acclimation to increased CO2 was found, neither were there consistent changes in transcription of RuBisCO or carbonic anhydrase genes. Non-calcified E. huxleyi CCMP1516 and calcified CCMP371 grown in gas equilibrated semi-continuous cultures for several weeks showed no change in cell division rate at 760 ppm CO2. An understanding of the underlying changes in communities is required for modelling responses to increasing CO2, molecular tools may prove useful for this task. The strong community response in the mesocosms shows that rising atmospheric CO2 can greatly affect phytoplankton productivity and biogeochemical cycling.EThOS - Electronic Theses Online ServiceNatural Environment Research CouncilGBUnited Kingdo

Predictable ecological response to rising CO2 of a community of marine phytoplankton

Rising atmospheric CO2 and ocean acidification are fundamentally altering conditions for life of all marine organisms, including phytoplankton. Differences in CO2 related physiology between major phytoplankton taxa lead to differences in their ability to take up and utilize CO2. These differences may cause predictable shifts in the composition of marine phytoplankton communities in response to rising atmospheric CO2. We report an experiment in which seven species of marine phytoplankton, belonging to four major taxonomic groups (cyanobacteria, chlorophytes, diatoms, and coccolithophores), were grown at both ambient (500 ?atm) and future (1,000 ?atm) CO2 levels. These phytoplankton were grown as individual species, as cultures of pairs of species and as a community assemblage of all seven species in two culture regimes (high?nitrogen batch cultures and lower?nitrogen semicontinuous cultures, although not under nitrogen limitation). All phytoplankton species tested in this study increased their growth rates under elevated CO2 independent of the culture regime. We also find that, despite species?specific variation in growth response to high CO2, the identity of major taxonomic groups provides a good prediction of changes in population growth and competitive ability under high CO2. The CO2?induced growth response is a good predictor of CO2?induced changes in competition (R2 > .93) and community composition (R2 > .73). This study suggests that it may be possible to infer how marine phytoplankton communities respond to rising CO2 levels from the knowledge of the physiology of major taxonomic groups, but that these predictions may require further characterization of these traits across a diversity of growth conditions. These findings must be validated in the context of limitation by other nutrients. Also, in natural communities of phytoplankton, numerous other factors that may all respond to changes in CO2, including nitrogen fixation, grazing, and variation in the limiting resource will likely complicate this prediction

Dermatoglyphic patterns in children with chronic constipation

Analysis of the fine ridge configurations on the digits of the palms and soles (dermatoglyphics) may sometimes help in the diagnoses of certain medical disorders. Dermatoglyphic patterns have been reported to be associated with congenital anomalies, such as congenital heart disease, duodenal ulcer, abdominal pain, and constipation. The palmar dermatoglyphic patterns of 77 children with constipation (39 functional and 38 organic constipation) were recorded. The control group consisted of 84 children with inguinal hernia. Those patients with at least one arch identified on any digit of either hand were termed arch positive. There was no significant correlation between arch positivity and constipation (functional or organic), or inguinal hernia (chi square, P =0.9211). Therefore, the presence of palmar arches cannot be used as a screening device for children with chronic constipation, especially of organic etiology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44424/1/10620_2005_Article_BF02285186.pd

The supernatural characters and powers of sacred trees in the Holy Land

This article surveys the beliefs concerning the supernatural characteristics and powers of sacred trees in Israel; it is based on a field study as well as a survey of the literature and includes 118 interviews with Muslims and Druze. Both the Muslims and Druze in this study attribute supernatural dimensions to sacred trees which are directly related to ancient, deep-rooted pagan traditions. The Muslims attribute similar divine powers to sacred trees as they do to the graves of their saints; the graves and the trees are both considered to be the abode of the soul of a saint which is the source of their miraculous powers. Any violation of a sacred tree would be strictly punished while leaving the opportunity for atonement and forgiveness. The Druze, who believe in the transmigration of souls, have similar traditions concerning sacred trees but with a different religious background. In polytheistic religions the sacred grove/forest is a centre of the community's official worship; any violation of the trees is regarded as a threat to the well being of the community. Punishments may thus be collective. In the monotheistic world (including Christianity, Islam and Druze) the pagan worship of trees was converted into the worship/adoration of saints/prophets; it is not a part of the official religion but rather a personal act and the punishments are exerted only on the violating individual

Brain regions showing white matter loss in Huntington's Disease are enriched for synaptic and metabolic genes

Background The earliest white matter changes in Huntington’s disease are seen before disease onset in the premanifest stage around the striatum, within the corpus callosum, and in posterior white matter tracts. While experimental evidence suggests that these changes may be related to abnormal gene transcription, we lack an understanding of the biological processes driving this regional vulnerability. Methods Here, we investigate the relationship between regional transcription in the healthy brain, using the Allen Institute for Brain Science transcriptome atlas, and regional white matter connectivity loss at three time points over 24 months in subjects with premanifest Huntington’s disease relative to control participants. The baseline cohort included 72 premanifest Huntington’s disease participants and 85 healthy control participants. Results We show that loss of corticostriatal, interhemispheric, and intrahemispheric white matter connections at baseline and over 24 months in premanifest Huntington’s disease is associated with gene expression profiles enriched for synaptic genes and metabolic genes. Corticostriatal gene expression profiles are predominately associated with motor, parietal, and occipital regions, while interhemispheric expression profiles are associated with frontotemporal regions. We also show that genes with known abnormal transcription in human Huntington’s disease and animal models are overrepresented in synaptic gene expression profiles, but not in metabolic gene expression profiles. Conclusions These findings suggest a dual mechanism of white matter vulnerability in Huntington’s disease, in which abnormal transcription of synaptic genes and metabolic disturbance not related to transcription may drive white matter loss