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Oxygen consumption in aquatic sediments is an indicator of overall biological activity of the ecosystem. As such, rates of sedimentary oxygen utilization are well documented for much of the open oceans and freshwater lakes. However, there are few direct measurements of sedimentary oxygen consumption from Antarctic subglacial aquatic sediments. We report the first microsensor oxygen profiles and derived sedimentary oxygen consumption rates from beneath the Ross Ice Shelf and a subglacial lake beneath the West Antarctic Ice Sheet. Rates of oxygen consumption in these two environments are relatively low, but comparable to those reported from ice‐free polar oceans and oligotrophic Arctic lakes. Our study demonstrates the presence of oxygen within Antarctic subglacial aquatic sediments and its importance for oxygen‐consuming microorganisms living in these ecosystems. [ABSTRACT FROM AUTHOR]

During the 2018–2019 Antarctic field season, the Subglacial Antarctic Lakes Scientific Access project team cleanly accessed Mercer Subglacial Lake, West Antarctica, to sample water and sediments beneath 1087 m of overlying ice. A multicorer was successful in sampling the sediment–water interface, with 4 deployments retrieving 10 cores between 0.3 and 0.4 m in length. Gravity coring was also successful, retrieving cores of 0.97 and 1.78 m in glacial diamict. However, sediment cores retrieved by the gravity cores were shorter than the core barrel penetration (as measured by mud streaks on the outside of the coring system), indicating that the system can likely be improved. This manuscript describes the design, implementation, successes, and lessons learned while coring sediments in a subglacial lake. [ABSTRACT FROM AUTHOR]

Aerobic methane production in aquatic ecosystems impacts the global atmospheric budget of methane, but the extent, mechanism, and taxa responsible for producing this greenhouse gas are not fully understood. Lake Bonney (LB), a perennially ice‐covered Antarctic lake, has cold hypersaline waters underlying an oxygenated freshwater layer. We present temporal methane concentration profiles in LB indicating methane production in the oxygenated (> 200% air saturation) water. Experiments amended with methylphosphonate (MPn) yielded methane generation, suggesting in situ methanogenesis via the carbon‐phosphorus (C‐P) lyase pathway. Enrichment cultures from the lake were used to isolate five bacterial strains capable of generating methane when supplied with MPn as the sole P source. Based on 16S rRNA gene sequencing, the isolates belong to the Proteobacteria (closely related to Marinomonas, Hoeflea, and Marinobacter genera) and Bacteroidetes (Algoriphagus genus). 16S rRNA metagenomic sequencing confirms the presence of these taxa in LB. None of the isolated species were reported to be capable to produce methane. In addition, orthologs of the phosphoenolpyruvate mutase gene (PepM) and methylphosphonate synthase (MPnS), enzymes involved in phosphonate and MPn biosynthesis, were widely spread in the LB shotgun metagenomic libraries; genes related to C‐P lyase pathways (phn gene clusters) were also abundant. 16S rRNA and mcrA genes of anaerobic methanogens were absent in both 16S rRNA and metagenomics libraries. These data reveal that in situ aerobic biological methane production is likely a significant source of methane in LB. [ABSTRACT FROM AUTHOR]

This paper examines the tax base elasticity of the regulated casino industry in Illinois to help estimate state-level revenue impacts of casino tax rate changes. Illinois' shift to a graduated rate schedule increased the highest marginal tax rate on casino adjusted gross receipts (AGR) from 20 percent to 70 percent before reverting to a 50 percent rate. We construct a state-level casino tax rate variable, which is a statewide average for each month of the marginal casino tax rate facing each casino. We find that a 1 percent increase in this state-level casino tax rate decreases overall Illinois casino AGR by around 1.1 percent. [ABSTRACT FROM AUTHOR]

Ice shelves surround ∼ 75% of Antarctica's coastline and are highly sensitive to climate change; several have recently collapsed and others are predicted to in the near future. Marine waters beneath ice shelves harbor active ecosystems, while adjacent seas can be important areas of bottom water formation. Despite their oceanographic significance, logistical constraints have resulted in few opportunities to directly sample sub-ice shelf cavities. Here, we present the first data on microbial diversity and biogeochemistry beneath the McMurdo Ice Shelf (MIS) near Ross Island, Antarctica. Physicochemical profiles obtained via a 56 m deep borehole through the MIS revealed three vertically layered water masses (Antarctic Surface Water [AASW], Ice Shelf Water [ISW], and modified High Salinity Shelf Water [mHSSW]). Metabolically active, moderately diverse (Shannon diversity from 2.06 to 5.74) microbial communities were detected in the AASW and mHSSW. Heterotrophic bacterial production and dissolved organic matter concentrations were higher (12-37% and 24%, respectively) in mHSSW relative to AASW. Chemoautotrophic production was 5.3 nmol C L−1 d−1 and 6.0 nmol C L−1 d−1 in the AASW and mHSSW, respectively. Phytoplankton cells were more abundant and larger in the mHSSW sample relative to the AASW, which indicates sinking of phytoplankton produced in surface waters and, together with southerly flowing currents (0.09-0.16 m s−1), horizontal advection of phytoplankton from McMurdo Sound. Advected phytoplankton carbon together with in situ chemoautotrophic production provide important sources of organic matter and other reduced compounds to support ecosystem processes in the dark waters in the ice shelf cavity. [ABSTRACT FROM AUTHOR]

Online commerce presents consumers with a convenient way of shopping outside of their local jurisdiction, and this online purchase decision is capable of affecting in significant ways the sales and use tax collections of state governments. However, the actual revenue impact has proven difficult to estimate. There is considerable work that examines the revenue impact of seller compliance with sales taxes. However, there is little work on buyer compliance with use taxes. In this paper, we investigate the potential impact of cross-border shopping on state use tax liabilities of buyers, using data from the largest online consumer-to-consumer and business-to-consumer marketplace, eBay.com. We collect our own data on actual cross-border shopping transactions from eBay, focusing upon a 'representative' commodity classification and a 'typical' day; these data consist of nearly 21,000 eBay listings generated by roughly 7,000 individual sellers with over 9,000 buyers. These data allow us to examine the extent of actual, not estimated, cross-border shopping by buyers, and the subsequent potential impact of this cross-border shopping on state use tax liabilities. Our results indicate that cross-border shopping is highly prevalent on eBay, with out-of-state purchases accounting for on average 94 percent of the volume of a state's purchase transactions. Even so, given the limited volume of eBay-based transactions relative to total sales transactions, the likely impact of cross-border transactions on state use tax revenue streams is quite low, at least at present, typically less than one percent of actual state sales tax revenues. [ABSTRACT FROM AUTHOR]

We use data on all Wisconsin municipalities during the period 1990-2003 to study the effect of tax increment finance (TIF) on economic development. We use appropriate statistical techniques to measure the impact of TIF and control variables on aggregate property values. We also examine the possibility communities that use TIF are self-selected. We find little evidence that TIF has led to significant increases in aggregate property values or that TIF increases the total value of residential and manufacturing property within a community. Surprisingly, we find positive impacts for commercial TIF districts. [ABSTRACT FROM AUTHOR]

Cross-sectional time series data in a partial adjustment model are used to examine county government fiscal behavior under a “hard” tax and expenditure limitation policy, an aggregate property tax levy limit, versus a “soft” limit under Truth in Taxation in Kansas. Results indicate that under the aggregate levy limit, per capita property taxes, own-source revenues and own-source expenditures were significantly higher than under the Truth in Taxation policy where local officials face many fewer restrictions on their ability to raise the levy. [ABSTRACT FROM AUTHOR]

Presents editorial changes and policies with regard the publication of the periodical "Contemporary Economic Policy," including total of articles and pages during the period of 2003-2004.

Since the early 1970s, litigation in many U.S. states has led to education finance reform. Over the same period, many states have imposed new tax and expenditure limitations (TELs) on local governments. The imposition of a TEL may alter how local and state education expenditures change subsequent to court-mandated decreases in spending inequality. Similarly, the effectiveness of TELs in limiting local education expenditures may be influenced by reform. To better evaluate the effects of reform and TELs on education spending, this article considers them jointly and finds that reform has a negative effect on local own-source education expenditures only in the presence of TELs. In the absence of court-ordered reform, TELs decrease own-source expenditure, but the effect is less pronounced than when TELs are present with reform. When both are present, state government spending on education is higher. Also TELs and court-ordered reform independently increase state government spending on education. [ABSTRACT FROM AUTHOR]

Although subglacial aquatic environments are widespread beneath the Antarctic ice sheet, subglacial biogeochemistry is not well understood, and the contribution of subglacial water to coastal ocean carbon and nutrient cycling remains poorly constrained. The Whillans Subglacial Lake (SLW) ecosystem is upstream from West Antarctica's Gould‐Siple Coast ~800 m beneath the surface of the Whillans Ice Stream. SLW hosts an active microbial ecosystem and is part of an active hydrological system that drains into the marine cavity beneath the adjacent Ross Ice Shelf. Here we examine sources and sinks for organic matter in the lake and estimate the freshwater carbon and nutrient delivery from discharges into the coastal embayment. Fluorescence‐based characterization of dissolved organic matter revealed microbially driven differences between sediment pore waters and lake water, with an increasing contribution from relict humic‐like dissolved organic matter with sediment depth. Mass balance calculations indicated that the pool of dissolved organic carbon in the SLW water column could be produced in 4.8 to 11.9 yr, which is a time frame similar to that of the lakes' fill‐drain cycle. Based on these estimates, subglacial lake water discharged at the Siple Coast could supply an average of 5,400% more than the heterotrophic carbon demand within Siple Coast embayments (6.5% for the entire Ross Ice Shelf cavity). Our results suggest that subglacial discharge represents a heretofore unappreciated source of microbially processed dissolved organic carbon and other nutrients to the Southern Ocean. Plain Language Summary: Antarctica's thick ice sheets cover a continent rich with liquid water. These subglacial aquatic environments are home to microbial ecosystems that process organic matter and nutrients important for all life. At the same time, subglacial water in Antarctica actively flows between basins and from subglacial basins to the edge of the continent where it mixes with seawater in coastal areas covered by ice shelves. The waters under these ice shelves are cold, dark, and contain low concentrations of organic carbon and nutrients. We used data from Whillans Subglacial Lake, which lies 800 m beneath the ice of West Antarctica, to understand the sources, sinks, and accumulation of organic matter in Antarctic subglacial aquatic environments. We then combined data from the same lake with data on subglacial hydrology in the region to determine whether inputs of subglacial organic matter and nutrients could be important in supporting life in the dark waters beneath the adjacent ice shelf. We found that the input of fresh water from the Antarctic continent to the surrounding ocean can meet the microbial demand for organic carbon and nutrients under the ice shelf. This work has implications for our understanding of Antarctica's influence on biology in the Southern Ocean. Key Points: A mass balance shows that dissolved organic carbon accumulation in Whillans Subglacial Lake is under hydrological and biological controlDifferences between the character of the water column and sediment porewater dissolved organic matter imply biological processingSubglacial outflows have the potential to subsidize biological activity under the world's largest ice shelf [ABSTRACT FROM AUTHOR]