Investigating sources of gaseous oxidized mercury in dry deposition at three sites across Florida, USA

Abstract. During 2009–2010, the State of Florida established a series of air quality monitoring stations to collect data for development of a statewide total maximum daily load (TMDL) for mercury (Hg). At three of these sites, located near Ft. Lauderdale (DVE), Pensacola (OLF), and Tampa Bay (TPA), passive samplers for the measurement of air Hg concentrations and surrogate surfaces for measurement of Hg dry deposition were deployed. While it is known that Hg in wet deposition in Florida is high compared to the rest of the United States, there is little information on Hg dry deposition. The objectives of the work were to: (1) investigate the utility of passive sampling systems for Hg in an area with low and consistent air concentrations as measured by the Tekran® mercury measurement system, (2) estimate dry deposition of gaseous oxidized Hg, and (3) investigate potential sources. This paper focuses on Objective 3. All sites were situated within 15 km of 1000 MW electricity generating plants (EGPs) and major highways. Bi-weekly dry deposition and passive sampler Hg uptake were not directly correlated with the automated Tekran® system measurements, and there was limited agreement between these systems for periods of high deposition. Using diel, biweekly, and seasonal Hg observations, and ancillary data collected at each site, the potential sources of Hg deposited to surrogate surfaces were investigated. With this information, we conclude that there are three major processes/sources contributing to Hg dry deposition in Florida, with these varying as a function of location and time of year. These include: (1) in situ oxidation of locally and regionally derived Hg facilitated by mobile source emissions, (2) indirect and direct inputs of Hg from local EGPs, and (3) direct input of Hg associated with long range transport of air from the Northeastern United States. We also suggest based on the data collected with the Tekran® and passive sampling systems that different chemical forms of GOM are associated with each of these sources.

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Investigating sources of gaseous oxidized mercury in dry deposition at three sites across Florida, USA

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-9201-2012 ◽

2012 ◽

Vol 12 (19) ◽

pp. 9201-9219 ◽

Cited By ~ 44

Author(s):

M. Sexauer Gustin ◽

P. S. Weiss-Penzias ◽

C. Peterson

Keyword(s):

United States ◽

Long Range ◽

Dry Deposition ◽

Passive Sampling ◽

Point Sources ◽

Long Range Transport ◽

Range Transport ◽

Potential Sources ◽

Sampling Systems ◽

Surrogate Surfaces

Abstract. During 2009–2010, the State of Florida established a series of air quality monitoring stations to collect data for development of a statewide total maximum daily load (TMDL) for mercury (Hg). At three of these sites, located near Ft. Lauderdale (DVE), Pensacola (OLF), and Tampa Bay (TPA), passive samplers for the measurement of air Hg concentrations and surrogate surfaces for measurement of Hg dry deposition were deployed. While it is known that Hg in wet deposition in Florida is high compared to the rest of the United States, there is little information on Hg dry deposition. The objectives of the work were to: (1) investigate the utility of passive sampling systems for Hg in an area with low and consistent air concentrations as measured by the Tekran® mercury measurement system, (2) estimate dry deposition of gaseous oxidized Hg, and (3) investigate potential sources. This paper focuses on Objective 3. All sites were situated within 15 km of 1000 MW electricity generating plants (EGPs) and major highways. Bi-weekly dry deposition and passive sampler Hg uptake were not directly correlated with the automated Tekran® system measurements, and there was limited agreement between these systems for periods of high deposition. Using diel, biweekly, and seasonal Hg observations, and ancillary data collected at each site, the potential sources of Hg deposited to surrogate surfaces were investigated. With this information, we conclude that there are three major processes/sources contributing to Hg dry deposition in Florida, with these varying as a function of location and time of year. These include: (1) in situ oxidation of locally and regionally derived Hg facilitated by mobile source emissions, (2) indirect and direct inputs of Hg from local EGPs, and (3) direct input of Hg associated with long range transport of air from the northeastern United States. Based on data collected with the surrogate surface sampling system, natural background dry deposition for Florida is estimated to be 0.03 ng m−2 h−1. Deposition associated with mobile sources is 0.10 ng m−2 h−1 at TPA and DVE, and 0.03 ng m−2 h−1 at OLF. Long range transport contributes 0.8 ng m−2 h−1 in the spring. At DVE ~0.10 ng m−2 h−1 is contributed directly or indirectly from local point sources. We also suggest based on the data collected with the Tekran® and passive sampling systems that different chemical forms of GOM are associated with each of these sources.

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The State of Bee Monitoring in the United States: A Call to Refocus Away From Bowl Traps and Towards More Effective Methods

Annals of the Entomological Society of America ◽

10.1093/aesa/saaa010 ◽

2020 ◽

Vol 113 (5) ◽

pp. 337-342 ◽

Cited By ~ 5

Author(s):

Zachary M Portman ◽

Bethanne Bruninga-Socolar ◽

Daniel P Cariveau

Keyword(s):

United States ◽

Passive Sampling ◽

Sampling Methods ◽

The United States ◽

Limited Resources ◽

Native Bees ◽

Robust Detection ◽

Current State ◽

Bee Abundance ◽

Meaningful Data

Abstract Effective monitoring is necessary to provide robust detection of bee declines. In the United States and worldwide, bowl traps have been increasingly used to monitor native bees and purportedly detect declines. However, bowl traps have a suite of flaws that make them poorly equipped to monitor bees. We outline the drawbacks of bowl traps, as well as other passive sampling methods. We emphasize that current methods do not monitor changes in bee abundance. We then propose future approaches to improve bee monitoring efforts, which include improving our understanding of the efficacy and drawbacks of current methods, novel molecular methods, nest censusing, mark-recapture, sampling of focal plant taxa, and detection of range contractions. Overall, we hope to highlight deficiencies of the current state of bee monitoring, with an aim to stimulate research into the efficacy of existing methods and promote novel methods that provide meaningful data that can detect declines without squandering limited resources.

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Global threat to agriculture from invasive species

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1602205113 ◽

2016 ◽

Vol 113 (27) ◽

pp. 7575-7579 ◽

Cited By ~ 224

Author(s):

Dean R. Paini ◽

Andy W. Sheppard ◽

David C. Cook ◽

Paul J. De Barro ◽

Susan P. Worner ◽

...

Keyword(s):

United States ◽

Invasive Species ◽

The United States ◽

African Countries ◽

Potential Threat ◽

Potential Cost ◽

Trade Patterns ◽

Species Invasions ◽

The World ◽

Potential Sources

Invasive species present significant threats to global agriculture, although how the magnitude and distribution of the threats vary between countries and regions remains unclear. Here, we present an analysis of almost 1,300 known invasive insect pests and pathogens, calculating the total potential cost of these species invading each of 124 countries of the world, as well as determining which countries present the greatest threat to the rest of the world given their trading partners and incumbent pool of invasive species. We find that countries vary in terms of potential threat from invasive species and also their role as potential sources, with apparently similar countries sometimes varying markedly depending on specifics of agricultural commodities and trade patterns. Overall, the biggest agricultural producers (China and the United States) could experience the greatest absolute cost from further species invasions. However, developing countries, in particular, Sub-Saharan African countries, appear most vulnerable in relative terms. Furthermore, China and the United States represent the greatest potential sources of invasive species for the rest of the world. The analysis reveals considerable scope for ongoing redistribution of known invasive pests and highlights the need for international cooperation to slow their spread.

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Sources of Resistance for Two Differentially Pathogenic Strains of Xanthomonas fragariae in Fragaria Genotypes

HortScience ◽

10.21273/hortsci.35.1.128 ◽

2000 ◽

Vol 35 (1) ◽

pp. 128-131 ◽

Cited By ~ 16

Author(s):

John L. Maas ◽

John S. Hartung ◽

Cristina Gouin-Behe ◽

Stan C. Hokanson

Keyword(s):

United States ◽

Control Strategies ◽

The United States ◽

Plant Production ◽

Strawberry Fruit ◽

Bacterial Strains ◽

Sources Of Resistance ◽

Xanthomonas Fragariae ◽

Potential Sources ◽

Nursery Plant

Bacterial angular leafspot disease (BALD) of strawberry (Fragaria sp. and F. ×ananassa Duchesne cultivars) has become increasingly destructive to strawberry fruit and plant production in Canada and the United States, as well as in other countries. The disease, caused by Xanthomonas fragariae Kennedy and King, was first documented in Minnesota in 1960, and has become of worldwide concern because of the economic impact of BALD in strawberry fruit and nursery-plant production and the lack of adequate disease control strategies. We tested 81 Fragaria genotypes, including representatives of F. ×ananassa, F. chiloensis (L.) Duchesne, F. virginiana Duchesne, and F. vesca L., for resistance to two pathogenic strains of X. fragariae. Two genotypes, a native F. virginiana from Minnesota and an F. virginiana × F. ×ananassa hybrid, were found to resist infection by both bacterial strains and may be potential sources of resistance to other strains of X. fragariae.

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Implementation of CCDC to produce the LCMAP Collection 1.0 annual land surface change product

10.5194/essd-2021-202 ◽

2021 ◽

Author(s):

George Xian ◽

Kelcy Smith ◽

Danika Wellington ◽

Josephine Horton ◽

Qiang Zhou ◽

...

Keyword(s):

United States ◽

Land Cover ◽

Land Cover Change ◽

Land Surface ◽

The United States ◽

Land Resource ◽

Land Change ◽

Continuous Change ◽

Ancillary Data ◽

Surface Change

Abstract. The increasing availability of high-quality remote sensing data and advanced technologies have spurred land cover mapping to characterize land change from local to global scales. However, most land change datasets either span multiple decades at a local scale or cover limited time over a larger geographic extent. Here, we present a new land cover and land surface change dataset created by the Land Change Monitoring, Assessment, and Projection (LCMAP) program over the conterminous United States (CONUS). The LCMAP land cover change dataset consists of annual land cover and land cover change products over the period 1985–2017 at 30-meter resolution using Landsat and other ancillary data via the Continuous Change Detection and Classification (CCDC) algorithm. In this paper, we describe our novel approach to implement the CCDC algorithm to produce the LCMAP product suite composed of five land cover and five land surface change related products. The LCMAP land cover products were validated using a collection of ~25,000 reference samples collected independently across CONUS. The overall agreement for all years of the LCMAP primary land cover product reached 82.5 %. The LCMAP products are produced through the LCMAP Information Warehouse and Data Store (IW+DS) and Shared Mesos Cluster systems that can process, store, and deliver all datasets for public access. To our knowledge, this is the first set of published 30 m annual land cover and land cover change datasets that span from the 1980s to the present for the United States. The LCMAP product suite provides useful information for land resource management and facilitates studies to improve the understanding of terrestrial ecosystems and the complex dynamics of the Earth system. The LCMAP system could be implemented to produce global land change products in the future.

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