Incorporating leaf chlorophyll content into a two-leaf terrestrial biosphere model for estimating carbon and water fluxes at a forest site

Chlorophyll is the main light-harvesting pigment in leaves, facilitating photosynthesis and indicating the supply of nitrogen for photosynthetic enzymes. In this study, we explore the feasibility of integrating leaf chlorophyll content (Chlleaf) into a Terrestrial Biosphere Model (TBM), as a proxy for the leaf maximum carboxylation rate at 25°C (Vmax25), for the purpose of improving carbon and water flux estimation. Measurements of Chlleaf and Vmax25 were made in a deciduous forest stand at the Borden Forest Research Station in southern Ontario, Canada, where carbon and water fluxes were measured by the eddy covariance method. The use of Chlleaf-based Vmax25 in the TBM significantly reduces the bias of estimated gross primary productivity (GPP) and evapotranspiration (ET) and improves the temporal correlations between the simulated and the measured fluxes, relative to the commonly employed cases of using specified constant Vmax25, leaf area index (LAI)-based Vmax25 or specific leaf area (SLA)-based Vmax25. The biggest improvements are found in spring and fall, when the mean absolute errors (MAEs) between modelled and measured GPP are reduced from between 2.2–3.2 to 1.8gCm−2d−1 in spring and from between 2.1–2.8 to 1.8gCm−2 d−1 in fall. The MAEs in ET estimates are reduced from 0.7–0.8mmd−1 to 0.6mmd−1 in spring, but no significant improvement is noted in autumn. A two-leaf upscaling scheme is used to account for the uneven distribution of incoming solar radiation inside canopies and the associated physiological differences between leaves. We found that modelled Vmax25 in sunlit leaves is 34% larger than in the shaded leaves of the same Chlleaf, which echoes previous physiological studies on light acclimation of plants. This study represents the first case of the incorporation of chlorophyll as a proxy for Vmax25 in a two-leaf TBM at a forest stand and demonstrates the efficacy of using chlorophyll to constrain Vmax25 and reduce the uncertainties in GPP and ET simulations

Leaf chlorophyll content as a proxy for leaf photosynthetic capacity.

Improving the accuracy of estimates of forest carbon exchange is a central priority for understanding ecosystem response to increased atmospheric CO2 levels and improving carbon cycle modelling. However, the spatially continuous parameterization of photosynthetic capacity (Vcmax) at global scales and appropriate temporal intervals within terrestrial biosphere models (TBMs) remains unresolved. This research investigates the use of biochemical parameters for modelling leaf photosynthetic capacity within a deciduous forest. Particular attention is given to the impacts of seasonality on both leaf biophysical variables and physiological processes, and their interdependent relationships. Four deciduous tree species were sampled across three growing seasons (2013-2015), approximately every 10 days for leaf chlorophyll content (ChlLeaf ) and canopy structure. Leaf nitrogen (NArea ) was also measured during 2014. Leaf photosynthesis was measured during 2014-2015 using a Li-6400 gas-exchange system, with A-Ci curves to model Vcmax. Results showed that seasonality and variations between species resulted in weak relationships between Vcmax normalized to 25°C (Vcmax25) and NArea (R2  = 0.62, P < 0.001), whereas ChlLeaf demonstrated a much stronger correlation with Vcmax25 (R2  = 0.78, P < 0.001). The relationship between ChlLeaf and NArea was also weak (R2  = 0.47, P < 0.001), possibly due to the dynamic partitioning of nitrogen, between and within photosynthetic and nonphotosynthetic fractions. The spatial and temporal variability of Vcmax25 was mapped using Landsat TM/ETM satellite data across the forest site, using physical models to derive ChlLeaf . TBMs largely treat photosynthetic parameters as either fixed constants or varying according to leaf nitrogen content. This research challenges assumptions that simple NArea -Vcmax25 relationships can reliably be used to constrain photosynthetic capacity in TBMs, even within the same plant functional type. It is suggested that ChlLeaf provides a more accurate, direct proxy for Vcmax25 and is also more easily retrievable from satellite data. These results have important implications for carbon modelling within deciduous ecosystems

Reviews

The Christian Goddess: Archetype and Theology in the Fantasies of George MacDonald. Bonnie Gaarden. Reviewed by Scott McLaren. Picturing Tolkien: Essays on Peter Jackson\u27s The Lord of the Rings Film Trilogy. Janice M. Bogstad and Philip E. Kaveny, eds. Reviewed by Emily E. Auger. Good Dragons are Rare: An Inquiry into Literary Dragons East and West. Fanfan Chen and Thomas Honegger, eds. Reviewed by David D. Oberhelman. Critical Perspectives on Philip Pullman\u27s His Dark Materials: Essays on the Novels, the Film and the Stage Productions. Steven Barfield and Katharine Cox, eds. Reviewed by Amy S. Rodgers. From Elvish to Klingon: Exploring Invented Languages. Michael Adams, ed. Reviewed by Harley J. Sims. Mythopoeic Narnia: Memory, Metaphor, and Metamorphoses in The Chronicles of Narnia. Salwa Khoddam. Reviewed by Holly Ordway. Abiding in the Sanctuary: The Waite-Trinick Tarot: A Christian Mystical Tarot (1917-1923). Tali Goodwin and Marcus Katz. Preface by Mary K. Greer. Reviewed by Emily E. Auger. Tolkien and Wales: Language, Literature, and Identity. Carl Phelpstead. Reviewed by Sara Brown. North Wind: A Journal of George MacDonald Studies. #29 (2010). Edited by Fernando Soto and John Pennington. Reviewed by Janet Brennan Croft. VII: An Anglo-American Literary Review. #28 (2011). Edited by Marjorie Lamp Mead et al. Reviewed by Janet Brennan Croft. Tolkien Studies: An Annual Scholarly Review. #8 (2011). Edited by Douglas A. Anderson, Michael D.C. Drout, and Verlyn Flieger. Reviewed by Janet Brennan Croft

Reviews

C.S. Lewis, Poetry, and the Great War 1914-1918. John Bremer. Reviewed by Joe R. Christopher. Collected Poems. Hope Mirrlees. Ed. and intro. Sandeep Parmar. Reviewed by Nicholas Birns. Fantasy, Art and Life: Essays on George MacDonald, Robert Louis Stevenson and Other Fantasy Writers. William Gray. Reviewed by Scott McLaren. C. S. Lewis and the Middle Ages. Robert Boenig. Reviewed by Holly Ordway. Sherlock Holmes for the 21st Century: Essays on New Adaptations. Edited by Lynnette Porter. Reviewed by Janet Brennan Croft. Dancing the Tao: Le Guin and Moral Development. Sandra J. Lindow. Reviewed by Carl Badgley. Hobbit Place-names: A Linguistic Excursion Through the Shire. Rainer Nagel. Reviewed by Troels Forchhammer. The Broken Scythe: Death and Immortality in the Works of J.R.R. Tolkien. Edited by Roberto Arduini and Claudio A. Testi. Reviewed by Harley J. Sims. The Hobbit Tarot. Terry Donaldson (author of guide pamphlet) and Peter Pracownik (artist). Reviewed by Emily A Auger. The Lord of the Rings Tarot Deck and Card Game. Terry Donaldson (author of guidebook), Peter Pracownik (artist), and Mike Fitzgerald (game rules). Reviewed by Emily A Auger. J.K. Rowling: Harry Potter. Edited by Cynthia J. Hallett and Peggy J. Huey. Reviewed by Janet Brennan Croft

Reviews

The International Relations of Middle-earth: Learning from The Lord of the Rings. Abigail E. Ruane and Patrick James. Reviewed by Robert T. Tally Jr Moments of Grace and Spiritual Warfare in The Lord of the Rings. Anne Marie Gazzolo. Reviewed by Damien Bador. The Wizard of Oz as American Myth: A Critical Study of Six Versions of the Story, 1900-2007. Alissa Burger. Reviewed by Hugh H. Davis. Plain to the Inward Eye: Selected Essays on C.S. Lewis. Don W. King. Reviewed by Holly Ordway. Tolkien\u27s Poetry. Ed. Julian Eilmann and Allan Turner. Reviewed by Joe R. Christopher. The Lion\u27s World: A Journey into the Heart of Narnia. Rowan Williams. Reviewed by Melody Green. C. S. Lewis - A Life: Eccentric Genius, Reluctant Prophet. Alister McGrath. Reviewed by Gregory Bassham. Seven: An Anglo-American Literary Review. Ed. Marjorie Lamp Mead. Reviewed by Janet Brennan Croft. Supernatural Studies: Official Publication of the Supernatural Studies Association. Ed. Margo Collins and Deborah Christie. Reviewed by Janet Brennan Croft. Fastitocalon: Studies in Fantasticism Ancient to Modern. Ed. Thomas Honegger and Fanfan Chen. Reviewed by Janet Brennan Croft. Wormwood: Literature of the Fantastic, Supernatural and Decadent. Edited by Mark Valentine. Reviewed by Janet Brennan Croft

Reviews

Peter Pan\u27s Shadows in the Literary Imagination. Kirsten Stirling. Reviewed by Kayla McKinney Wiggins. C.S. Lewis and the Church: Essays in Honour of Walter Hooper. Ed. Judith Wolfe and B.N. Wolfe. Reviewed by Joe R. Christopher. Deadly Powers: Animal Predators and the Mythic Imagination. Paul A. Trout. Reviewed by Lizzy Walker. The Mythological Dimensions of Neil Gaiman. Anthony S. Burdge, Jessica Burke, and Kristine Larsen, eds. Reviewed by Nicholas Birns. Animals and Humans: Recurrent Symbiosis in Archaeology and Old Norse Religion. Kristina Jennbert. Reviewed by Emily E. Auger. Tolkien in Translation. Edited by Thomas Honegger. Reviewed by Harley J. Sims. Translating Tolkien: Text and Film. Ed. Thomas Honegger. Reviewed by Sara Brown. Critical Discourses on the Fantastic, 1712-1831. David Sandner. Reviewed by Joe Young. Arthurian Figures of History and Legend: A Biographical Dictionary. Frank D. Reno. Reviewed by Donald T. Williams. The Loss and the Silence: Aspects of Modernism in the Works of C.S. Lewis, J.RR. Tolkien, and Charles Williams. Margaret Hiley. Reviewed by Holly Ordway. Buffy and the Heroine’s Journey: Vampire Slayer as Feminine Chosen One. Valerie Estelle Frankel. Reviewed by Janet Brennan Croft. North Wind: A Journal of George MacDonald Studies. #30 (2011). Edited by Fernando Soto and John Pennington. Reviewed by Janet Brennan Croft. Mallorn: The Journal of the Tolkien Society. #53 (Spring 2012). Ed. Henry Gee. Reviewed by Janet Brennan Croft. Tolkien Studies: An Annual Scholarly Review. #9 (2012). Ed. Verlyn Flieger and Michael D.C. Drout. Reviewed by Janet Brennan Croft. Fastitocalon: Studies in Fantasticism Ancient to Modern. #2.1&2 (2011). Ed. Thomas Honegger and Fanfan Chen. Reviewed by Janet Brennan Croft

Reviews

George MacDonald: Divine Carelessness and Fairytale Levity. Daniel Gabelman. Reviewed by Bonnie Gaarden. The Gender Dance: Ironic Subversion in C.S. Lewis\u27s Cosmic Trilogy. Monika B. Hilder. Preface by Matthew Dickerson. Reviewed by Joe R. Christopher. Sir Gawain and the Green Knight: In a Modern English Version with a Critical Introduction. John Gardner. Reviewed by Perry Neil Harrison. Myths of Light: Eastern Metaphors of the Eternal. Joseph Campbell. Reviewed by Christopher Tuthill. The Riddles of the Hobbit. Adam Roberts. Reviewed by Jon Garrad. The Modern Literary Werewolf: A Critical Study of the Mutable Motif. Brent A. Stypczynski. Reviewed by Sharon L. Bolding. Fairy Tales Reimagined: Essays on New Retellings. Ed. by Susan Redington Bobby. Reviewed by Kazia Estrada. C.S. Lewis\u27s Perelandra: Reshaping the Image of the Cosmos. Ed. Judith Wolfe and Brendan Wolfe. Reviewed by Holly Ordway. The Ideal of Kingship in the Writings of Charles Williams, C.S. Lewis, and J.R.R. Tolkien: Divine Kingship is Reflected in Middle-Earth. Christopher Scarf. Reviewed by Melody Green. The Ring of Words: Tolkien and the Oxford English Dictionary. By Peter Gilliver, Jeremy Marshall, and Edmund Weiner. Reviewed by Mike Foster. Tolkien: The Forest and the City. Ed. Helen Conrad-O\u27Briain and Gerard Hynes. Reviewed by T.S. Miller. Tolkien Studies X. Edited by Michael D.C. Drout, Verlyn Flieger, and David Bratman. Reviewed by Janet Brennan Croft. Seven: An Anglo-American Literary Review 30. Edited by Marjorie Lamp Mead. Reviewed by Janet Brennan Croft

Proximity Interactions in a Permanently Housed Dairy Herd: Network Structure, Consistency, and Individual Differences

Understanding the herd structure of housed dairy cows has the potential to reveal preferential interactions, detect changes in behavior indicative of illness, and optimize farm management regimes. This study investigated the structure and consistency of the proximity interaction network of a permanently housed commercial dairy herd throughout October 2014, using data collected from a wireless local positioning system. Herd-level networks were determined from sustained proximity interactions (pairs of cows continuously within three meters for 60 s or longer), and assessed for social differentiation, temporal stability, and the influence of individual-level characteristics such as lameness, parity, and days in milk. We determined the level of inter-individual variation in proximity interactions across the full barn housing, and for specific functional zones within it (feeding, non-feeding). The observed networks were highly connected and temporally varied, with significant preferential assortment, and inter-individual variation in daily interactions in the non-feeding zone. We found no clear social assortment by lameness, parity, or days in milk. Our study demonstrates the potential benefits of automated tracking technology to monitor the proximity interactions of individual animals within large, commercially relevant groups of livestock

Bunching behaviour in housed dairy cows at higher ambient temperatures.

Bunching behavior in cattle may occur for several reasons including enabling social interactions, a response to stress or danger, or due to shared interest in resources such as feeding or watering areas. There is evidence in pasture grazed cattle that bunching may occur more frequently at higher ambient temperatures, possibly due to sharing of fly-load or to seek shade from the direct sun under heat stress conditions. Here we demonstrate how bunching behavior is associated with higher ambient temperatures in a barn-housed UK dairy herd. A real-time local positioning system (RTLS) was used, as part of a precision livestock farming (PLF) approach, to track the spatial position and activity of a commercial dairy herd (c100 cows) in a freestall barn continuously at high temporal resolution for 4 mo between August and November 2014. Bunching was determined using 4 different spatial measures determined on an hourly basis: herd full and core range size, mean herd inter-cow distance (ICD), and mean herd nearest neighbor distance (NND). For hourly mean ambient temperatures above 20°C, the herd showed higher bunching behavior with increasing ambient temperature (i.e., reduced full and core range size, ICD, and NND). Aggregated space-use intensity was found to positively correlate with localized variations in temperature across the barn (as measured by animal mounted sensors), but the level of correlation decreased at higher ambient barn temperatures. Bunching behavior may increase localized temperatures experienced by individuals and hence may be a maladaptive behavioral response in housed dairy cattle, which are known to suffer heat stress at higher temperatures. Our study is the first to use high-resolution positional data to provide evidence of associations between bunching behavior and higher ambient temperatures for a barn-housed dairy herd in a temperate region (UK). Further studies are needed to explore the exact mechanisms for this response to inform both welfare and production management

Rheumatoid synovial fibroblasts differentiate into distinct subsets in the presence of cytokines and cartilage

Background We investigated two distinct synovial fibroblast populations that were located preferentially in the lining or sub-lining layers and defined by their expression of either podoplanin (PDPN) or CD248, and explored their ability to undergo self-assembly and transmigration in vivo. Methods Synovial fibroblasts (SF) were cultured in vitro and phenotypic changes following stimulation with interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β1 were examined. To examine the phenotype of SF in vivo, a severe combined immunodeficiency (SCID) human-mouse model of cartilage destruction was utilised. Results SF in the lining layer in rheumatoid arthritis (RA) expressed high levels of PDPN compared to the normal synovium, whereas CD248 expression was restricted to sub-lining layer cells. TNF-α or IL1 stimulation in vitro resulted in an increased expression of PDPN. In contrast, stimulation with TGF-β1 induced CD248 expression. In the SCID human-mouse model, rheumatoid SF recapitulated the expression of PDPN and CD248. Fibroblasts adjacent to cartilage expressed PDPN, and attached to, invaded, and degraded cartilage. PDPN+ CD248– SF preceded the appearance of PDPN– CD248+ cells in contralateral implants. Conclusions We have identified two distinct SF populations identified by expression of either PDPN or CD248 which are located within different anatomical compartments of the inflamed synovial membrane. These markers discriminate between SF subsets with distinct biological properties. As PDPN-expressing cells are associated with early fibroblast migration and cartilage erosion in vivo, we propose that PDPN-expressing cells may be an attractive therapeutic target in RA.</p