The fractal dimension of star-forming regions at different spatial scales in M33

We study the distribution of stars, HII regions, molecular gas, and individual giant molecular clouds in M33 over a wide range of spatial scales. The clustering strength of these components is systematically estimated through the fractal dimension. We find scale-free behavior at small spatial scales and a transition to a larger correlation dimension (consistent with a nearly uniform distribution) at larger scales. The transition region lies in the range 500-1000 pc. This transition defines a characteristic size that separates the regime of small-scale turbulent motion from that of large-scale galactic dynamics. At small spatial scales, bright young stars and molecular gas are distributed with nearly the same three-dimensional fractal dimension (Df <= 1.9), whereas fainter stars and HII regions exhibit higher values (Df = 2.2-2.5). Our results indicate that the interstellar medium in M33 is on average more fragmented and irregular than in the Milky Way.Comment: 18 pages including 4 figures. Accepted for publication in Ap

Observations of carbon export by small sinking particles in the upper mesopelagic

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Chemistry 175 (2015): 72-81, doi:10.1016/j.marchem.2015.02.011.Carbon and nutrients are transported out of the surface ocean and sequestered at depth by sinking particles. Sinking particle sizes span many orders of magnitude and the relative influence of small particles on carbon export compared to large particles has not been resolved. To determine the influence of particle size on carbon export, the flux of both small (11–64 μm) and large (> 64 μm) particles in the upper mesopelagic was examined during 5 cruises of the Bermuda Atlantic Time Series (BATS) in the Sargasso Sea using neutrally buoyant sediment traps mounted with tubes containing polyacrylamide gel layers and tubes containing a poisoned brine layer. Particles were also collected in surface-tethered, free-floating traps at higher carbon flux locations in the tropical and subtropical South Atlantic Ocean. Particle sizes spanning three orders of magnitude were resolved in gel samples, included sinking particles as small as 11 μm. At BATS, the number flux of small particles tended to increase with depth, whereas the number flux of large particles tended to decrease with depth. The carbon content of different sized particles could not be modeled by a single set of parameters because the particle composition varied across locations and over time. The modeled carbon flux by small particles at BATS, including all samples and depths, was 39 ± 20% of the modeled total carbon flux, and the percentage increased with depth in 4 out of the 5 months sampled. These results indicate that small particles (< 64 μm) are actively settling in the water column and are an important contributor to carbon flux throughout the mesopelagic. Observations and models that overlook these particles will underestimate the vertical flux of organic matter in the ocean.Funding for this study was provided by the National Science Foundation Chemical Oceanography Program (OCE-1260001 and 1406552 to M. L. Estapa) and the Woods Hole Oceanographic Institution Devonshire Postdoctoral Scholarship awarded to C. A. Durkin. Funding for the DeepDOM cruise was provided by the National Science Foundation Chemical Oceanography Program (OCE-1154320 to E. B. Kujawinski and K. Longnecker, WHOI)

Decoupling of net community and export production on submesoscales in the Sargasso Sea

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 29 (2015): 1266–1282, doi:10.1002/2014GB004913.Determinations of the net community production (NCP) in the upper ocean and the particle export production (EP) should balance over long time and large spatial scales. However, recent modeling studies suggest that a horizontal decoupling of flux-regulating processes on submesoscales (≤10 km) could lead to imbalances between individual determinations of NCP and EP. Here we sampled mixed-layer biogeochemical parameters and proxies for NCP and EP during 10, high-spatial resolution (~2 km) surface transects across strong physical gradients in the Sargasso Sea. We observed strong biogeochemical and carbon flux variability in nearly all transects. Spatial coherence among measured biogeochemical parameters within transects was common but rarely did the same parameters covary consistently across transects. Spatial variability was greater in parameters associated with higher trophic levels, such as chlorophyll in >5.0 µm particles, and variability in EP exceeded that of NCP in nearly all cases. Within sampling transects, coincident EP and NCP determinations were uncorrelated. However, when averaged over each transect (30 to 40 km in length), we found NCP and EP to be significantly and positively correlated (R = 0.72, p = 0.04). Transect-averaged EP determinations were slightly smaller than similar NCP values (Type-II regression slope of 0.93, standard deviation = 0.32) but not significantly different from a 1:1 relationship. The results show the importance of appropriate sampling scales when deriving carbon flux budgets from upper ocean observations.NASA Ocean Carbon and Biogeochemistry program Grant Number: NNX11AL94G; WHOI Postdoctoral Scholar fellowship; NASA ACE Grant Number: NNX12AJ25G; NSF Grant Number: OCE-07523662016-02-2

Reification and Fetishism: Processes of Transformation

Reification, fetishism, alienation, mastery, and control – these are some of the key concepts of modernity that have been battered and beaten by postmoderns and nonmoderns alike, with Bruno Latour, a nonmodern, discarding them most recently. Critical of this approach, which creates a rift between moderns and nonmoderns, the author engages in dialogue with modern thinkers – particularly Peter Berger, Thomas Luckmann and Stanley Pullberg – with a view to recycling and redefining the concept of reification from a nonmodern perspective. Marxian scholars associate reification with an attitude of detachment and passivity. The author seeks to convert the negative and asymmetrical Marxian reading of reification, which places subjects above objects, to a positive symmetry. Marx explained the capitalist economy through the lens of religion. Reversing the direction of symmetrical comparison, the author considers the northwestern Zambian universe of ancestors through the lens of Marxian concepts, mainly reification and fetishism. There is much to gain from recycling the old concept of reification. In a non-partisan symmetrical perspective, the redefinition of reification as fetishism yields a new, positive understanding of the place of material and immaterial things in social life and the ways in which we humans apprehend the world and implicate those things in our projects and struggles. Reification is not an impediment to action but a condition for action

Autonomous, high-resolution observations of particle flux in the oligotrophic ocean

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeosciences 10 (2013): 5517-5531, doi:10.5194/bg-10-5517-2013.Observational gaps limit our understanding of particle flux attenuation through the upper mesopelagic because available measurements (sediment traps and radiochemical tracers) have limited temporal resolution, are labor-intensive, and require ship support. Here, we conceptually evaluate an autonomous, optical proxy-based method for high-resolution observations of particle flux. We present four continuous records of particle flux collected with autonomous profiling floats in the western Sargasso Sea and the subtropical North Pacific, as well as one shorter record of depth-resolved particle flux near the Bermuda Atlantic Time-series Study (BATS) and Oceanic Flux Program (OFP) sites. These observations illustrate strong variability in particle flux over very short (~1-day) timescales, but at longer timescales they reflect patterns of variability previously recorded during sediment trap time series. While particle flux attenuation at BATS/OFP agreed with the canonical power-law model when observations were averaged over a month, flux attenuation was highly variable on timescales of 1–3 days. Particle fluxes at different depths were decoupled from one another and from particle concentrations and chlorophyll fluorescence in the immediately overlying surface water, consistent with horizontal advection of settling particles. We finally present an approach for calibrating this optical proxy in units of carbon flux, discuss in detail the related, inherent physical and optical assumptions, and look forward toward the requirements for the quantitative application of this method in highly time-resolved studies of particle export and flux attenuation.M.L.E. was supported by a WHOI Postdoctoral Scholar fellowship, and the floats used in this project were funded by the above NASA grant and by ONR (DURIP, N00014-10-1-0776)

Rate and apparent quantum yield of photodissolution of sedimentary organic matter

Author Posting. © Association for the Sciences of Limnology and Oceanography, 2012. This article is posted here by permission of Association for the Sciences of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 57 (2012): 1743-1756, doi:10.4319/lo.2012.57.6.1743.We quantified rates of photochemical dissolution (photodissolution) of organic carbon in coastal Louisiana suspended sediments, conducting experiments under well-defined conditions of irradiance and temperature. Optical properties of the suspended sediments were characterized and used in a radiative transfer model to compute irradiances within turbid suspensions. Photodissolution rate increased with temperature (T), with activation energy of 32 ± 7 kJ mol−1, which implicates indirect (non-photochemical) steps in the net reaction. In most samples, dissolved organic carbon (DOC) concentration increased approximately linearly with time over the first 4 h of irradiation under broadband simulated sunlight, after higher rates in the initial hour of irradiation. Four-hour rates ranged from 2.3 µmol DOC m−3 s−1 to 3.2 µmol DOC m−3 s−1, but showed no relation to sample origin within the study area, organic carbon or reducible iron content, or mass-specific absorption coefficient. First-hour rates were higher—from 3.5 µmol DOC m−3 s−1 to 7.8 µmol DOC m−3 s−1—and correlated well with sediment reducible iron (itself often associated with organic matter). The spectral apparent quantum yield (AQY) for photodissolution was computed by fitting DOC photoproduction rates under different spectral irradiance distributions to corresponding rates of light absorption by particles. The photodissolution AQY magnitude is similar to most published dissolved-phase AQY spectra for dissolved inorganic carbon photoproduction, which suggests that in turbid coastal waters where particles dominate light absorption, DOC photoproduction from particles exceeds photooxidation of DOC.We would like to acknowledge funding support from the National Science Foundation Chemical Oceanography program (L.M. and M.L.E.), a National Aeronautics and Space Administration Earth Systems Science Graduate Fellowship (M.L.E.), and the Office of Naval Research Environmental Optics program (E.B.)

Particle dynamics in the rising plume at Piccard Hydrothermal Field, Mid-Cayman Rise

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 2762–2774, doi:10.1002/2015GC005831.Processes active in rising hydrothermal plumes, such as precipitation, particle aggregation, and biological growth, affect particle size distributions and can exert important influences on the biogeochemical impact of submarine venting of iron to the oceans and their sediments. However, observations to date of particle size distribution within these systems are both limited and conflicting. In a novel buoyant hydrothermal plume study at the recently discovered high-temperature (398°C) Piccard Hydrothermal Field, Mid-Cayman Rise, we report optical measurements of particle size distributions (PSDs). We describe the plume PSD in terms of a simple, power-law model commonly used in studies of upper and coastal ocean particle dynamics. Observed PSD slopes, derived from spectral beam attenuation and laser diffraction measurements, are among the highest found to date anywhere in the ocean and ranged from 2.9 to 8.5. Beam attenuation at 650 nm ranged from near zero to a rarely observed maximum of 192 m−1 at 3.5 m above the vent. We did not find large (>100 μm) particles that would settle rapidly to the sediments. Instead, beam attenuation was well-correlated to total iron, suggesting the first-order importance of particle dilution, rather than precipitation or dissolution, in the rising plume at Piccard. Our observations at Piccard caution against the assumption of rapid deposition of hydrothermal, particulate metal fluxes, and illustrate the need for more particle size and composition measurements across a broader range of sites, globally.This work was funded by the National Science Foundation (OCE-1029223; OCE-1061863), NASA (NNX09AB75G) and Woods Hole Oceanographic Institution's Deep Ocean Exploration Institute and Ocean Ridge Initiative. Ship time (R/V Falkor cruise FK008) was funded by the Schmidt Ocean Institute and M.L.E. was supported by a WHOI Postdoctoral Scholar fellowship.2016-02-2

MDOCS Tri-Fold-2014-06-01, Storytellers\u27 Institute Skidmore Fellows Application Tri-Fold

Tri-fold pamphlet inviting Skidmore students and faculty to apply for the inaugural (June 2015) Storytellers\u27 institute

An Aesthetic of Resourcefulness: Japanese Folk Textiles from the Edo Period and Beyond

This paper describes the place in time - the vernacular context in social, economic, cultural and geographic terms - in which specific utilitarian textiles -- sakiori, shifu and boro -- were produced in Japan from, roughly, the Edo (or Tokugawa), through the Meiji, Taisho, and Showa periods, or 1600 to the mid-1900\u27s. Sakiori, shifu and boro clothing and household textiles incorporated re-purposed, recycled fibers and materials in response to conditions of poverty and harsh living conditions in rural Japan. These utilitarian artifacts affect particular aesthetic qualities, reflective of the conditions within which they were originally produced, and are resonant, to some contemporary audiences, in their simplicity and humility of a late 20th and early 21st century modernist sensibility