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  1. Abstract

    Phago-mixotrophy, the combination of photoautotrophy and phagotrophy in mixoplankton, organisms that can combine both trophic strategies, have gained increasing attention over the past decade. It is now recognized that a substantial number of protistan plankton species engage in phago-mixotrophy to obtain nutrients for growth and reproduction under a range of environmental conditions. Unfortunately, our current understanding of mixoplankton in aquatic systems significantly lags behind our understanding of zooplankton and phytoplankton, limiting our ability to fully comprehend the role of mixoplankton (and phago-mixotrophy) in the plankton food web and biogeochemical cycling. Here, we put forward five research directions that we believe will lead to major advancement in the field: (i) evolution: understanding mixotrophy in the context of the evolutionary transition from phagotrophy to photoautotrophy; (ii) traits and trade-offs: identifying the key traits and trade-offs constraining mixotrophic metabolisms; (iii) biogeography: large-scale patterns of mixoplankton distribution; (iv) biogeochemistry and trophic transfer: understanding mixoplankton as conduits of nutrients and energy; and (v) in situ methods: improving the identification of in situ mixoplankton and their phago-mixotrophic activity.

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  2. Abstract

    Electrically evoked compound action potentials (ECAPs) generated in the subthalamic nucleus (STN) contain features that may be useful for titrating deep brain stimulation (DBS) therapy for Parkinson’s disease. Delivering a strong therapeutic effect with DBS therapies, however, relies on selectively targeting neural pathways to avoid inducing side effects. In this study, we investigated the spatiotemporal features of ECAPs in and around the STN across parameter sweeps of stimulation current amplitude, pulse width, and electrode configuration, and used a linear classifier of ECAP responses to predict electrode location. Four non-human primates were implanted unilaterally with either a directional (n = 3) or non-directional (n = 1) DBS lead targeting the sensorimotor STN. ECAP responses were characterized by primary features (within 1.6 ms after a stimulus pulse) and secondary features (between 1.6 and 7.4 ms after a stimulus pulse). Using these features, a linear classifier was able to accurately differentiate electrodes within the STN versus dorsal to the STN in all four subjects. ECAP responses varied systematically with recording and stimulating electrode locations, which provides a subject-specific neuroanatomical basis for selecting electrode configurations in the treatment of Parkinson’s disease with DBS therapy.

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  3. Abstract

    Mixotrophic oligotrich ciliates use plastids sequestered from algal prey to acquire energy and metabolic products from photosynthesis. We isolated mixotrophic oligotrichs from coastal waters off Massachusetts (MA) and California (CA), as well as from two freshwater ponds in MA, and identified associated plastid 23S rRNA genes. Ciliates were identified using a combination of microscopy and 18S rRNA phylogeny, and includedLaboea strobilaand variousPseudotontonia,Spirotontonia, andStrombidiumspecies from marine waters, andLimnostrombidium viridefrom freshwater. Overall, nearly half of all plastid sequences recovered from ciliates were haptophytes, followed by 15–20% for stramenopiles and chlorophytes, and < 10% originating from cryptophyte algae. No plastid sequences were from dinoflagellates. Cells ofStrombidium ‘biarmatum’collected from coastal MA in spring and fall possessed mostlyMicromonasplastids, but during spring also possessed cryptophyte sequences. During spring,L. strobilawere found to have a mix of chlorophyte, cryptophyte, haptophyte, and stramenopile sequences, while a co‐occurringStrombidiumsp. had mostly chlorophyte and haptophyte sequences. MixotrophicPseudotontoniaandSpirotontoniaspp. were sampled during summer from coastal MA and in Monterey Bay, CA, and cells from both populations were dominated (> 70%) by haptophyte plastids of similar phylogenetic origin.L. viridewere also evaluated from two freshwater ponds and possessed mostlyChrysochromulinasp. (haptophyte) and synurid (stramenopile) sequences. These results are the first survey of the genetic diversity of plastids associated with pelagic mixotrophic oligotrich ciliates and suggest that some species may selectively retain plastids from certain algal groups, while others appear to be generalists.

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  4. Abstract Aim

    Coffee is an important export for many developing countries, with a global annual trade value of $100 billion, but it is threatened by a warming climate. Shade trees may mitigate the effects of climate change through temperature regulation that can aid in coffee growth, slow pest reproduction, and sustain avian insectivore diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics.


    East Africa.


    We created current and future regional Maxent models for avian insectivores in East Africa using Worldclim temperature data and observations from the Global Biodiversity Information Database. We then adjusted current and future bioclimatic layers based on mean differences in temperature between shade and sun coffee farms and projected the models using these adjusted layers to predict the impact of shade tree removal on climatic suitability for avian insectivores.


    Existing Worldclim temperature layers more closely matched temperatures under shade trees than temperatures in the open. Removal of shade trees, through warmer temperatures alone, would result in reduction of avian insectivore species by over 25%, a loss equivalent to 50 years of climate change under the most optimistic emissions scenario. Under the most extreme climate scenario and removal of shade trees, insectivore richness is projected to decline from a mean of 38 to fewer than 8 avian insectivore species.

    Main conclusions

    We found that shade trees on coffee farms already provide important cooler microclimates for avian insectivores. Future temperatures will become a regionally limiting factor for bird distribution in East Africa, which could negatively impact control of coffee pests, but the effect of climate change can be potentially mediated through planting and maintaining shade trees on coffee farms.

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