Ungaged inflow and loss patterns in urban and agricultural sub-reaches of the Logan River Observatory

Streams in semi-arid urban and agricultural environments are often heavily diverted for anthropogenic purposes. However, they simultaneously receive substantial inflows from a variety of ungaged sources including stormwater returns, tile drainage, and irrigation runoff that help sustain flow during dry periods. Due to the inability to identify sources or directly gage many of these inflows, there is a clear need for methods to understand source origination while quantifying potential gains and losses over highly impacted reaches. In the context of the Logan River Observatory, historical gage data illustrate the importance of ungaged and unidentified inflows on maintaining or enhancing flows in both urban and agricultural reaches containing large diversions. To understand the inflows in this portion of the Logan River, we first analysed water samples for ions collected from a subset of representative inflow sources and applied clustering analyses to establish inflow source classifications and associated ion concentration ranges. These representative concentration ranges, combined with mainstem flow and river ion samples taken at sub-reach scales, allow for the application of flow and mass balances to quantify inflow rates from different sources as well as any losses. These calculations demonstrate significant gains and losses occurring in many sub-reaches during three sampling events. The dominant land use (urban or agriculture) and flow regime at the time of sampling were the primary drivers of gains and losses. These exchanges were found to be most important below large diversions during low flow conditions. This highlights the need to classify inflow sources (urban or agriculture, surface or groundwater) and estimate their contributions to anticipate instream consequences of land use and water management decisions. As irrigation and water conveyance practices become more efficient, a portion of these ungaged inflows could be diminished or eliminated, thus further depleting streamflow during dry periods.     

An Analysis of Environmental and Economic Impacts of Fossil Fuel Production in the U.S. from 2001 to 2015

The production and burning of fossil fuels is the primary contributor to CO₂ emissions for the U.S. We assess the impact of producing coal, crude oil, and natural gas on the environment and economic well-being by analyzing state-level data from 2001 to 2015. Our findings show that coal production has led to more CO₂ emissions and no significant benefit to economic well-being. Crude oil production has a non-significant impact on CO₂ emissions but is related to a lower poverty rate, a higher median household income, and a higher employment rate. Natural gas withdrawals have a positive impact on median household income. We discuss these findings in the context of current U.S. energy policies and then provide directions for future research.     

Zooplankton community structure in a cyclonic and mode-water eddy in the Sargasso Sea

Mesoscale eddies are important suppliers of nutrients to the surface waters of oligotrophic gyres, but little is known about the biological response, particularly that of higher trophic levels, to these physical perturbations. During the summers of 2004 and 2005, we followed the development of a cyclonic eddy and an anti-cyclonic mode-water eddy in the Sargasso Sea. Zooplankton (>150 μm) were collected across both eddies in 9 discrete depth intervals between 0 and 700 m. Comparison of the abundance of major taxa of mesozooplankton in the upper 150 m at eddy center and outside the eddies (day and night) indicated that the cyclone and mode-water eddy supported similar mesozooplankton communities, with several taxa significantly higher in abundance inside than outside the eddies, when compared with the Bermuda Atlantic Time-series Study site as representative of mean conditions. In both eddies copepod peak abundance occurred in the 50-100 m depth interval, coincident with the chlorophyll a maximum, suggesting elevated food concentration in the eddies may have influenced zooplankton vertical distribution. The two eddies differed in the strength of diel vertical migration of zooplankton, as indicated by the ratio of night:day abundance in the epipelagic zone, which was higher at the center of the mode-water eddy for most taxa. Over the sampling interval of 1-2 months, abundance of the three most common taxa (copepods, chaetognaths, and ostracods) decreased in the cyclone and increased in the mode-water eddy. This further supports previous findings that over the sampling period the cyclone was in a decay phase, while the mode-water eddy was sustaining nutrient fluxes and high phytoplankton concentrations. A more detailed analysis of community structure in the mode-water eddy indicated the 0-700 m integrated abundance of doliolids was significantly higher inside the mode-water eddy than outside. The presence of a mesopelagic (200-700 m) layer of lepadid barnacle cyprids in this eddy highlights the potential of eddies to transport and disperse biota. We conclude that when compared with average ambient conditions (as measured at BATS), mesoscale eddies can influence zooplankton behavior and alter zooplankton community structure which can affect food-web interactions and biogeochemical cycling in the open ocean.     

Recruitment of the Crabs Eurypanopeus depressus, Rhithropanopeus harrisii, and Petrolisthes armatus to Oyster Reefs: the Influence of Freshwater Inflow

Oyster reefs provide structural habitat for resident crabs and fishes, most of which have planktonic larvae that are dependent upon transport/retention processes for successful settlement. High rates of freshwater inflow have the potential to disrupt these processes, creating spatial gaps between larval distribution and settlement habitat. To investigate whether inflow can impact subsequent recruitment to oyster reefs, densities of crab larvae and post-settlement juveniles and adults were compared in Estero Bay, Florida, over 22 months (2005–2006). Three species were selected for comparison: Petrolisthes armatus, Eurypanopeus depressus, and Rhithropanopeus harrisii. All are important members of oyster reef communities in Southwest Florida; all exhibit protracted spawning, with larvae present throughout the year; and each is distributed unevenly on reefs in different salinity regimes. Recruitment to oyster reefs was positively correlated with bay-wide larval supply at all five reefs examined. Species-specific larval connectivity to settlement sites was altered by inflow: where connectivity was enhanced by increased inflow, stock–recruitment curves were linear; where connectivity was reduced by high inflows, stock–recruitment curves were asymptotic at higher larval densities. Maximum recruit density varied by an order of magnitude among reefs. Although live oyster density was a good indicator of habitat quality in regard to crab density, it did not account for the high variability in recruit densities. Variation in recruit density at higher levels of larval supply may primarily be caused by inflow-induced variation in larval connectivity, creating an abiotic simulation of what has widely been regarded as density dependence in stock–recruitment curves.     

The intersection of corporate social responsibility guidelines and indigenous rights: Examining neoliberal governance of a proposed mining project in Suriname

With neoliberal reforms and the growth of multinational mining investment in developing countries, corporate social responsibility (CSR) has become notable (and debatable) for its potential to fill a social and environmental governance gap. As yet, there has been limited analytical attention paid to the political struggles and power dynamics that get reflected through specific CSR guidelines and their implementation in local contexts; this is particularly apparent with respect to the human rights dimension of CSR, and more specifically, indigenous rights. This study documents the debates, issues of accountability, and different interpretations of CSR between NGOs representing indigenous rights and a mining corporation. These debates focus on environmental impact assessments; indigenous rights to land; and the indigenous right to Free, Prior, and Informed Consent. These exchanges illustrate the socio-political, as well as economic, positioning of these actors, and the different agendas associated with their positions that determine issues of accountability and shape alternate interpretations of CSR guidelines. The outcomes of these debates also reflect the different degrees of power that these actors hold in such contexts, irrespective of the strength or validity of their arguments about CSR. This dialogue is thereby a lens into the more complex and contentious entanglements that emerge with CSR as a mode of governance, as it plays out ‘on the ground.’ These findings also reinforce questions regarding what we can expect of CSR as a mode of governance for addressing human rights issues with resource extraction projects, particularly within the constraints of overriding political and social structures.