More Like this

1. Response to Comments on “Designing river flows to improve food security futures in the Lower Mekong Basin”

   https://doi.org/10.1126/science.aat1477  

   Holtgrieve, GW (July 2018, Science)

   Sabo et al. presented an empirically derived algorithm defining the socioecological response of the Tonle Sap Dai fishery in the Cambodian Mekong to basin-scale variation in hydrologic flow regime. Williams suggests that the analysis leading to the algorithm is flawed because of the large distance between the gauge used to measure water levels (hydrology) and the site of harvest for the fishery. Halls and Moyle argue that Sabo et al.’s findings are well known and contend that the algorithm is not a comprehensive assessment of sustainability. We argue that Williams’ critique stems from a misunderstanding about our analysis; further clarification of the analysis is provided. We regret not citing more of the work indicated by Halls and Moyle, yet we note that our empirical analysis provides additional new insights into Mekong flow-fishery relationships. 

   more » « less
2. Towards Haudenosaunee research sovereignty: Investing in local research and training to support community development

   https://doi.org/10.56367/OAG-046-11487  

   Martin-Hill, Dawn; Jamieson, Rebecca; Gibson, Colin M; Monteith, Hiliary; Patel, Rohini; Krantzberg, Gail (January 2025, Open Access Government)

   Towards Haudenosaunee research sovereignty: Investing in local research and training to support community developmentThe article emphasizes the importance of Indigenous Research Governance in Six Nations of the Grand River, addressing the harmful historical effects of academic research on Indigenous Peoples and advocating for structural changes that promote Indigenous data sovereignty and community ownership of research. In both Canada and the United States, academic research has long been part of the colonial project (Hodge, 2012; Williams et al., 2020). The impact research has had on Indigenous Peoples has resulted in a legacy of deep mistrust and negative perception of research by many Indigenous communities (Garrison et al., 2023). Indigenous scholars and leaders who have advocated for repairing this relationship have led major transformations away from the way in which research has traditionally been approached and administered. Most recent paradigm and policy shifts seek to support the establishment of self-determined Indigenous Research Governance (Garba et al., 2023; Morton et al., 2017), which encapsulates many interconnected key concepts, including Indigenous data sovereignty (Schnarch, 2004; Kukutai & Taylor, 2016; Cannon et al., 2024), Indigenous research ethics (Castellano, 2004; Kuhn et al., 2020; Fournier et al., 2023), Indigenous/ decolonizing methodologies (Kovach, 2009; Smith, 2021), and Indigenous epistemologies (McGregor et al., 2010; Karanja, 2019). 

   more » « less
3. Simulation of REE mobility and evolution of F-NaCl-CO2-bearing fluids in hydrothermal calcite and fluorite ore-forming veins

   https://doi.org/10.7185/gold2021.6309  

   Costa Filho, D.; Gysi, A.P. (July 2021, Goldschmidt)

   Rare earth element (REE) deposits are commonly associated with carbonatites and (per)alkaline rocks where hydrothermal magmatic fluids can play a significant role in REE mobilization and deposition [1]. Thermodynamic modeling permits predicting the evolution of ore-forming fluids and can be used to test different controls on hydrothermal REE mobility including temperature, pressure, the solubility of REE minerals, aqueous REE speciation and pH evolution associated with fluid-rock interaction. Previous modeling studies either focused on REE fluoride/chloride complexation in acidic aqueous fluids [2] or near neutral/alkaline fluids associated with calcite vein formation [3]. Such models were also applied to interpret field observations in REE deposits Bayan Obo in China and Bear Lodge in Wyoming [3,4]. Recent hydrothermal calcite-fluid REE partitioning experiments provide new data to simulate the solubility of REE in calcite, REE carbonates/fluorocarbonates at high temperatures [5, 6]. We studied the competing effects controlling the mobility of REE in hydrothermal fluids between 100 and 400 °C at 500 bar. Speciation calculations were carried out in the Ca-F-CO2-Na-Cl-H2O system using the GEMS code package [7]. The properties of minerals and aqueous species were taken from the MINES thermodynamic database [3,5]. The Gallinas Mountains hydrothermal REE deposit in New Mexico was used as a field analogue to compare our models with the formation of calcite-fluorite veins hosting bastnäsite. Previous fluid inclusion studies hypothesized that the REE were transported as fluoride complexes [8] but more recent modeling studies have shown that fluoride essentially acts as a depositing ligand [2]. Here we show more detailed simulations predicting the stability of fluorite, calcite and REE minerals relevant to ore-forming processes in carbonatites and alkaline systems. [1] Gysi et al. (2016), Econ. Geol. 111, 1241-1276; [2] Migdisov and Williams-Jones (2014), Mineral. Deposita 49, 987-997. [3] Perry and Gysi (2018), Geofluids; [4] Liu et al. (2020), Minerals 10, 495; [5] Perry and Gysi (2020), Geochim. Cosmochim. Acta 286, 177-197; [6] Gysi and Williams-Jones (2015) Chem. Geol. 392, 87-101;[7] Kulik et al. (2013), Computat. Geosci. 17, 1-24; [8] Williams-Jones et al. (2000), Econ. Geol. 95, 327-341 

   more » « less
4. Image Analysis to Quantify Coral Bleaching Using Greyscale Model

   https://doi.org/10.17504/protocols.io.bx8wprxe  

   McLachlan, RH; Grottoli, AG (January 2021, Protocolsio)

   This protocol outlines a method of quantitatively measuring the degree of bleaching of a coral colony nondestructively in the field using image analysis. Previous studies have shown that mean intensity grey (MIG), also known as percent whiteness, is highly correlated with chlorophyll a and Symbiodiniaceae density (Chow et al. 2016, Amid et al. 2018), and therefore can be used to quantify the bleaching intensity of a coral colony. Color analysis can be done using digital photographs of live coral colonies either in situ (e.g., Maguire et al. 2003) or exsitu in the lab (Amid et al. 2018; this protocol). Photographs must be taken prior to any preservation or processing of tissue, such as freezing, use of preservatives or fixatives, airbrushing etc., to ensure no alteration of the original coral color occurs. In this protocol, corals are photographed in front of a white reference standard and the resulting color images are subsequently converted to 8-bit greyscale and analyzed. There are two steps to this protocol: 1) Photographing live coral fragments 2) Image analysis of mean grey value 

   more » « less
5. Hydrothermal Rare Earth Elements (REE) Partitioning into Fluorite: A Fluid Inclusion Study from the Gallinas Mountains REE-bearing Fluorite Deposit, NM

   https://doi.org/10.56577/SM-2024.2978  

   Velmani, Aadish; Gysi, Alexander; Hurtig, Nicole (April 2024, New Mexico Geological Society)

   are earth elements (REE) are becoming increasingly important in modern society due to their numerous uses in manufacturing of components for green and high-tech energy industries. Studying the mechanisms of REE mineral formation in geologic systems is vital for understanding where and how these mineral deposits form. Previous studies of REE mineral deposits have shown that hydrothermal fluids can play a key role in the mobilization and enrichment of REE (Williams-Jones et al., 2000; Gysi et al., 2016; Vasyukova and Williams-Jones, 2018). Fluorite is ideal to study the behavior of REE because of their compatibility in its structure and it is a ubiquitous hydrothermal vein mineral found together with REE fluorocarbonates (i.e., bastnäsite and parisite). However, the controls on hydrothermal fluid-mineral REE partitioning in these deposits are not yet fully understood. In this study, we present petrographic observations of fluorite veins and fluid inclusions from the Gallinas Mountains REE-bearing fluorite veins/breccia deposit in New Mexico (McLemore, 2010; Williams-Jones et al. 2000). The Gallinas Mountains deposit notably contains hydrothermal fluorite and bastnäsite, and is associated with ~30 Ma alkaline igneous rocks intruded into Permian sedimentary rocks (McLemore, 2010). The goal of this study is to better understand the cause of REE variations in fluorite as a function of temperature and salinity of the fluids, and to determine how the REE concentrations change in barren and mineralized veins. Optical microscopy and cold-cathode cathodoluminescence (CL) is used to distinguish different fluorite generations and fluid inclusion types. Scanning electron microscopy (SEM) is used to identify REE minerals, zonation in fluorite, and acquire elemental compositions of different vein minerals. 

   more » « less