Michael Mallin - Academia.edu (original) (raw)
Papers by Michael Mallin
Water, Jul 1, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
decreasing species richness and catch-per-unit-effort in the electroshocking surveys may be devel... more decreasing species richness and catch-per-unit-effort in the electroshocking surveys may be developing and should be closely monitored in future surveys.
Springer eBooks, 2001
Coastal areas in the United States and many other countries are considered to be desirable region... more Coastal areas in the United States and many other countries are considered to be desirable regions to live and recreate. However, as human use of coastal land and water increases, so does the incidence of aquatic-borne disease from contact with contaminated water and eating contaminated shellfish. Movement of humans into coastal areas both greatly increases the number of sources of microbial pathogens and radically alters the landscape through increased construction activity and paving of former natural areas. On a regional scale, increases in human population over a 14-year period in coastal North Carolina were strongly correlated with increases in shellfish bed closures due to high fecal coliform bacterial counts. On a watershed scale, an analysis of several tidal creeks found strong correlations between mean estuarine fecal coliform bacterial counts and watershed population, percent developed area and especially with percent impervious surface coverage. Conversion of natural landscapes to impervious surfaces (roads, drives, sidewalks, parking lots and roofs) removes the land's natural filtration capability, allows for increased concentration of pollutants at the land's surface and provides a means of rapid conveyance of pollutants to downstream waterways. An analysis of rural watersheds in the Coastal Plain found that stream fecal coliform counts and turbidity were both strongly correlated with rainfall in the previous 24 h in watersheds containing extensive industrial swine and poultry operations, as well as watersheds containing more traditional agriculture and cattle husbandry. In contrast, in watersheds rich in swamp wetlands these relationships were not significant, even in watersheds containing extensive animal production. Based on these findings, we suggest that waterborne microbial pathogen abundance can be minimized in urbanizing coastal areas through reduced use of impervious surfaces and maximal use of natural or constructed wetlands for passive stormwater runoff treatment. In animal husbandry areas, retention of natural wetlands and management practices designed to minimize sediment runoff can likely reduce inputs of pathogenic microbes into streams.
Oyster reef work as performed by the UNCW benthic Ecology Laboratory is continuing on the tidal c... more Oyster reef work as performed by the UNCW benthic Ecology Laboratory is continuing on the tidal creeks, with emphasis on Howe, Hewletts and Pages creeks. There seems to be a good supply of larval oysters into the creeks that settle on all available areas of shell. In 2006 live oyster density was greatest in Howe Creek, but older shell material apparently is rapidly covered by sediments coming in from upstream construction activities. Pages Creek had the highest percent coverage of both live and dead shell material. There were no consistent differences among the three creeks with respect to oyster reef complexity (called rugosity) and condition of the individual oysters. Individual oyster condition was elevated in 2006, but in summer 2005 and 2007 it was comparable to oyster conditions found in some highly impacted systems in Chesapeake Bay. The majority of the oyster population in the tidal creeks appears to be in the sublegal size range (45-55mm). We expected to see a shift in the size distribution toward a greater percentage of larger (>75mm) oysters since none of the areas sampled are subject to harvest pressure. This does not appear to be the case. The UNCW Benthic Ecology Lab continues to evaluate potential causes of the for the loss of larger size class of oyster. Based on finding reported in 2006 this loss does not appear to be the result of DERMO infections that although highly prevalent, were not intense.
Lake and reservoir management, Jan 2, 2022
Abstract Iraola ND, Mallin MA, Cahoon LB, Gamble DW, Zamora PB. 2022. Nutrient dynamics in a eutr... more Abstract Iraola ND, Mallin MA, Cahoon LB, Gamble DW, Zamora PB. 2022. Nutrient dynamics in a eutrophic blackwater urban lake. Lake Reserv Manage. 38:28–46. Greenfield Lake is a eutrophic blackwater urban lake in Wilmington, North Carolina, and in 2014 was declared by the state as impaired waters due to excessive chlorophyll a concentrations. Phytoplankton production is strongly nitrogen (N) limited, and the lake supports filamentous green algal blooms in spring and N-fixing cyanobacteria blooms in summer. To inform future lake restoration efforts, we quantified nutrient loads from 5 perennial streams that drain the highly impervious Greenfield Lake watershed to determine their impact on the lake’s eutrophic state. The 5 streams were sampled monthly from 2016 to 2017 during periods of dry weather and again after rain events of at least 1.2 cm to compare stormwater runoff to baseflow conditions. Two streams alone accounted for 76% of inorganic N and 63% of inorganic P surface inflow, whereas 2 other streams, despite high (53–74%) impervious coverage, had low loading. A lake-wide sediment phosphorus survey also revealed P accumulations mirrored streams of high nutrient load, while low P accumulations were in areas draining streams with large wetland and stormwater treatment areas. Drainage area was positively correlated with nitrate concentration and nitrate and ammonium loading. Unconventionally, percent impervious coverage was negatively correlated with nutrient concentrations and loads; we suspect that the presence of a large golf course in the watershed with the lowest impervious cover was a key driving factor. Our work also demonstrates the significance of catchment features: Drainages with large stormwater retention structures and significant natural wetlands in the lower reaches yielded low nutrient loadings.
Elsevier eBooks, 2019
Abstract Coastal waters of the Carolinas include some magnificent resources that are increasingly... more Abstract Coastal waters of the Carolinas include some magnificent resources that are increasingly degraded from upstream pollution and poorly controlled local development. Escalating water demands have rapidly depressed coastal water tables. Upper watershed industries, cities, and croplands contaminate coastal riverine potable source waters with a wide array of unregulated/poorly regulated toxic substances, and with nutrients that fuel nuisance algal blooms. Industrialized livestock production adds fecal microbes and many other contaminants to surface and groundwaters. Toxic cyanobacteria blooms have spread into newly affected freshwaters including potable source waters. Physical reengineering of coastal landscapes with numerous detention ponds has created ideal incubation sites for noxious estuarine/marine dinoflagellate and raphidiophycean blooms. Stormwater runoff from sprawling coastal development alters the sediment composition and benthic fauna of receiving waters, while also adding toxic chemicals and fecal contaminants that threaten human health and seafood safety. These impacts are expected to be exacerbated by warming trends in climate change.
Marine Pollution Bulletin, 2021
Polyethylene terephthalate (PET) is frequently used in the food and beverage industry and therefo... more Polyethylene terephthalate (PET) is frequently used in the food and beverage industry and therefore contributes greatly to plastic marine debris. The fecal pollution indicator bacteria Enterococcus is used for marine water contamination assessments and is regularly found in storm water discharge. In order to examine if PET drinking bottles act as refuges for Enterococcus, a study was conducted within euhaline tidal waters of Wrightsville Beach, NC, USA via the deployment of bottle floats positioned nearby two stormwater outfall pipes. Bottles were retrieved weekly to assess the accumulation of fecal bacteria and phytoplankton. Each bottle was analyzed for the presence of Enterococcus on plastic surfaces and within water inside the bottle. Abundance of Enterococcus and planktonic chlorophyll α was found to be significantly greater in association with PET bottles versus the surrounding waters. Bottles were observed to act as reservoirs for both Enterococcus and phytoplankton with concentrations well above the state, federal, and WHO standards.
The United States Environmental Protection Agency considers nutrient pollution in stream ecosyste... more The United States Environmental Protection Agency considers nutrient pollution in stream ecosystems one of the U.S. most pressing environmental challenges. But limited independent replicates, lack of experimental randomization, and space- and time-varying confounding handicap causal inference on effects of nutrient pollution. In this paper the causal g-methods developed by Robins and colleagues are extended to allow for exposures to vary in time and space in order to assess the effects of nutrient pollution on chlorophyll a, a proxy for algal production. Publicly available data from the North Carolina Cape Fear River and a simulation study are used to show how causal effects of upstream nutrient concentrations on downstream chlorophyll a levels may be estimated from typical water quality monitoring data. Estimates obtained from the parametric g-formula, a marginal structural model, and a structural nested model indicate that chlorophyll a concentrations at Lock and Dam 1 were influe...
Purpose: To explore the extent to which Scottish pre-eminence in accounting texts in the eighteen... more Purpose: To explore the extent to which Scottish pre-eminence in accounting texts in the eighteenth century was influenced by religion. By so doing, to add to the literature on the relationship between religion and accountability. Design/methodology/approach: An examination of religion as social practice is conducted by examining the relationship between formal, printed, sources, and the extensive archives of the Church of Scotland. A sample of five administrative units of the church is used to explore local practice in detail. Findings: Accountability was at the heart of the theology of the Church of Scotland. It shaped local practices of accountability to give what is termed 'systemic accountability', which featured the detailed specification of roles and the recording of transactions. Lay involvement in this system was extensive amongst the 'middling sort'. This system formed the backdrop to the Scottish preeminence in accounting texts, facilitated by widespread literacy and a propensity to publish, both in turn shaped by the broader religious context. Research limitations/implications: the research is confined to Scotland and does not consider the wider impact on areas such as British North America. The value of examining religion as a relationship between belief and social practice could be extended to other belief systems, as the article only considers the Reformed Protestant tradition of Christianity. Practical implications (if applicable) Social implications (if applicable) Originality/value: The value is in a detailed investigation of religion as a social practice, which has not been presented before in the context of accountability. It presents a new perspective on Scottish accomplishments in the field of accounting, accomplishments which have been of significance for the broader profession. Work on the impact of religion on accounting has challenged a division between the sacred and the profane, where accounting is seen to be proper to the latter (
Numerous phytoplankton-oriented ecological studies have been conducted since 1965 in the extensiv... more Numerous phytoplankton-oriented ecological studies have been conducted since 1965 in the extensive North Carolina estuarine system. Throughout a range of geomorphological estuarine types, a basic underlying pattern of phytoplankton productivity and abundance following water temperature seasonal fluctuations was observed. Overlying this solar-driven pattern was a secondary forcing mechanism consisting of a complex interaction between meteorology and hydrology, resulting in periodic winter or early spring algal blooms and productivity pulses in the lower riverine estuaries. Wet winters caused abundant nitrate to reach the lower estuaries and stimulate the blooms, whereas dry winters resulted in low winter phytoplankton abundance and primary production. Dinoflagellates (Heterocapsa triquetra, Prorocen- trum minimum, Gymnodinium spp.) and various cryptomonads dominated these cool-weather estuarine blooms. Sounds were less productive than the riverine estuaries, and were dominated by dia...
Phytoplankton primary production and its environmental regulation were examined at 3 stations rep... more Phytoplankton primary production and its environmental regulation were examined at 3 stations representative of the lower Neuse River Estuary near the Pamlico Sound interface. This study covered a 3-year period (November 1987-October 1990). The authors also examined the roles of the major phytoplankton nutrients nitrogen and phosphorus in controlling growth and bloom formation. The overall potential for nuisance blooms and associated episodes of bottom water hypoxia and anoxia was investigated in field studies. Algal biomass and production varied seasonally, with high values in summer and low values in winter. In situ nutrient addition bioassays indicated the estuary experienced a general state of N limitation with especially profound limitation during summer periods. The authors recommendations for a management strategy include reductions in Dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and suspended sediment loads in order to maintain the system in a nu...
Journal of the American Statistical Association, 2019
The United States Environmental Protection Agency considers nutrient pollution in stream ecosyste... more The United States Environmental Protection Agency considers nutrient pollution in stream ecosystems one of the U.S.' most pressing environmental challenges. But limited independent replicates, lack of experimental randomization, and space-and time-varying confounding handicap causal inference on effects of nutrient pollution. In this paper the causal g-methods are extended to allow for exposures to vary in time * We would like to thank Dr. Rebecca Benner and the Nature Conservancy of North Carolina for compiling and providing the data. We would also like to thank all those who collected and collated these data in order to protect the Cape Fear watershed. The causal inference with interference research group at UNC (Brian Barkley, Sujatro Chakladar, and Wen Wei Loh) plus Mary Kirk Wilkinson provided helpful feedback and critical support throughout this project. We also thank the Associate Editor and two anonymous for helpful comments.
Water, Jul 1, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
decreasing species richness and catch-per-unit-effort in the electroshocking surveys may be devel... more decreasing species richness and catch-per-unit-effort in the electroshocking surveys may be developing and should be closely monitored in future surveys.
Springer eBooks, 2001
Coastal areas in the United States and many other countries are considered to be desirable region... more Coastal areas in the United States and many other countries are considered to be desirable regions to live and recreate. However, as human use of coastal land and water increases, so does the incidence of aquatic-borne disease from contact with contaminated water and eating contaminated shellfish. Movement of humans into coastal areas both greatly increases the number of sources of microbial pathogens and radically alters the landscape through increased construction activity and paving of former natural areas. On a regional scale, increases in human population over a 14-year period in coastal North Carolina were strongly correlated with increases in shellfish bed closures due to high fecal coliform bacterial counts. On a watershed scale, an analysis of several tidal creeks found strong correlations between mean estuarine fecal coliform bacterial counts and watershed population, percent developed area and especially with percent impervious surface coverage. Conversion of natural landscapes to impervious surfaces (roads, drives, sidewalks, parking lots and roofs) removes the land's natural filtration capability, allows for increased concentration of pollutants at the land's surface and provides a means of rapid conveyance of pollutants to downstream waterways. An analysis of rural watersheds in the Coastal Plain found that stream fecal coliform counts and turbidity were both strongly correlated with rainfall in the previous 24 h in watersheds containing extensive industrial swine and poultry operations, as well as watersheds containing more traditional agriculture and cattle husbandry. In contrast, in watersheds rich in swamp wetlands these relationships were not significant, even in watersheds containing extensive animal production. Based on these findings, we suggest that waterborne microbial pathogen abundance can be minimized in urbanizing coastal areas through reduced use of impervious surfaces and maximal use of natural or constructed wetlands for passive stormwater runoff treatment. In animal husbandry areas, retention of natural wetlands and management practices designed to minimize sediment runoff can likely reduce inputs of pathogenic microbes into streams.
Oyster reef work as performed by the UNCW benthic Ecology Laboratory is continuing on the tidal c... more Oyster reef work as performed by the UNCW benthic Ecology Laboratory is continuing on the tidal creeks, with emphasis on Howe, Hewletts and Pages creeks. There seems to be a good supply of larval oysters into the creeks that settle on all available areas of shell. In 2006 live oyster density was greatest in Howe Creek, but older shell material apparently is rapidly covered by sediments coming in from upstream construction activities. Pages Creek had the highest percent coverage of both live and dead shell material. There were no consistent differences among the three creeks with respect to oyster reef complexity (called rugosity) and condition of the individual oysters. Individual oyster condition was elevated in 2006, but in summer 2005 and 2007 it was comparable to oyster conditions found in some highly impacted systems in Chesapeake Bay. The majority of the oyster population in the tidal creeks appears to be in the sublegal size range (45-55mm). We expected to see a shift in the size distribution toward a greater percentage of larger (>75mm) oysters since none of the areas sampled are subject to harvest pressure. This does not appear to be the case. The UNCW Benthic Ecology Lab continues to evaluate potential causes of the for the loss of larger size class of oyster. Based on finding reported in 2006 this loss does not appear to be the result of DERMO infections that although highly prevalent, were not intense.
Lake and reservoir management, Jan 2, 2022
Abstract Iraola ND, Mallin MA, Cahoon LB, Gamble DW, Zamora PB. 2022. Nutrient dynamics in a eutr... more Abstract Iraola ND, Mallin MA, Cahoon LB, Gamble DW, Zamora PB. 2022. Nutrient dynamics in a eutrophic blackwater urban lake. Lake Reserv Manage. 38:28–46. Greenfield Lake is a eutrophic blackwater urban lake in Wilmington, North Carolina, and in 2014 was declared by the state as impaired waters due to excessive chlorophyll a concentrations. Phytoplankton production is strongly nitrogen (N) limited, and the lake supports filamentous green algal blooms in spring and N-fixing cyanobacteria blooms in summer. To inform future lake restoration efforts, we quantified nutrient loads from 5 perennial streams that drain the highly impervious Greenfield Lake watershed to determine their impact on the lake’s eutrophic state. The 5 streams were sampled monthly from 2016 to 2017 during periods of dry weather and again after rain events of at least 1.2 cm to compare stormwater runoff to baseflow conditions. Two streams alone accounted for 76% of inorganic N and 63% of inorganic P surface inflow, whereas 2 other streams, despite high (53–74%) impervious coverage, had low loading. A lake-wide sediment phosphorus survey also revealed P accumulations mirrored streams of high nutrient load, while low P accumulations were in areas draining streams with large wetland and stormwater treatment areas. Drainage area was positively correlated with nitrate concentration and nitrate and ammonium loading. Unconventionally, percent impervious coverage was negatively correlated with nutrient concentrations and loads; we suspect that the presence of a large golf course in the watershed with the lowest impervious cover was a key driving factor. Our work also demonstrates the significance of catchment features: Drainages with large stormwater retention structures and significant natural wetlands in the lower reaches yielded low nutrient loadings.
Elsevier eBooks, 2019
Abstract Coastal waters of the Carolinas include some magnificent resources that are increasingly... more Abstract Coastal waters of the Carolinas include some magnificent resources that are increasingly degraded from upstream pollution and poorly controlled local development. Escalating water demands have rapidly depressed coastal water tables. Upper watershed industries, cities, and croplands contaminate coastal riverine potable source waters with a wide array of unregulated/poorly regulated toxic substances, and with nutrients that fuel nuisance algal blooms. Industrialized livestock production adds fecal microbes and many other contaminants to surface and groundwaters. Toxic cyanobacteria blooms have spread into newly affected freshwaters including potable source waters. Physical reengineering of coastal landscapes with numerous detention ponds has created ideal incubation sites for noxious estuarine/marine dinoflagellate and raphidiophycean blooms. Stormwater runoff from sprawling coastal development alters the sediment composition and benthic fauna of receiving waters, while also adding toxic chemicals and fecal contaminants that threaten human health and seafood safety. These impacts are expected to be exacerbated by warming trends in climate change.
Marine Pollution Bulletin, 2021
Polyethylene terephthalate (PET) is frequently used in the food and beverage industry and therefo... more Polyethylene terephthalate (PET) is frequently used in the food and beverage industry and therefore contributes greatly to plastic marine debris. The fecal pollution indicator bacteria Enterococcus is used for marine water contamination assessments and is regularly found in storm water discharge. In order to examine if PET drinking bottles act as refuges for Enterococcus, a study was conducted within euhaline tidal waters of Wrightsville Beach, NC, USA via the deployment of bottle floats positioned nearby two stormwater outfall pipes. Bottles were retrieved weekly to assess the accumulation of fecal bacteria and phytoplankton. Each bottle was analyzed for the presence of Enterococcus on plastic surfaces and within water inside the bottle. Abundance of Enterococcus and planktonic chlorophyll α was found to be significantly greater in association with PET bottles versus the surrounding waters. Bottles were observed to act as reservoirs for both Enterococcus and phytoplankton with concentrations well above the state, federal, and WHO standards.
The United States Environmental Protection Agency considers nutrient pollution in stream ecosyste... more The United States Environmental Protection Agency considers nutrient pollution in stream ecosystems one of the U.S. most pressing environmental challenges. But limited independent replicates, lack of experimental randomization, and space- and time-varying confounding handicap causal inference on effects of nutrient pollution. In this paper the causal g-methods developed by Robins and colleagues are extended to allow for exposures to vary in time and space in order to assess the effects of nutrient pollution on chlorophyll a, a proxy for algal production. Publicly available data from the North Carolina Cape Fear River and a simulation study are used to show how causal effects of upstream nutrient concentrations on downstream chlorophyll a levels may be estimated from typical water quality monitoring data. Estimates obtained from the parametric g-formula, a marginal structural model, and a structural nested model indicate that chlorophyll a concentrations at Lock and Dam 1 were influe...
Purpose: To explore the extent to which Scottish pre-eminence in accounting texts in the eighteen... more Purpose: To explore the extent to which Scottish pre-eminence in accounting texts in the eighteenth century was influenced by religion. By so doing, to add to the literature on the relationship between religion and accountability. Design/methodology/approach: An examination of religion as social practice is conducted by examining the relationship between formal, printed, sources, and the extensive archives of the Church of Scotland. A sample of five administrative units of the church is used to explore local practice in detail. Findings: Accountability was at the heart of the theology of the Church of Scotland. It shaped local practices of accountability to give what is termed 'systemic accountability', which featured the detailed specification of roles and the recording of transactions. Lay involvement in this system was extensive amongst the 'middling sort'. This system formed the backdrop to the Scottish preeminence in accounting texts, facilitated by widespread literacy and a propensity to publish, both in turn shaped by the broader religious context. Research limitations/implications: the research is confined to Scotland and does not consider the wider impact on areas such as British North America. The value of examining religion as a relationship between belief and social practice could be extended to other belief systems, as the article only considers the Reformed Protestant tradition of Christianity. Practical implications (if applicable) Social implications (if applicable) Originality/value: The value is in a detailed investigation of religion as a social practice, which has not been presented before in the context of accountability. It presents a new perspective on Scottish accomplishments in the field of accounting, accomplishments which have been of significance for the broader profession. Work on the impact of religion on accounting has challenged a division between the sacred and the profane, where accounting is seen to be proper to the latter (
Numerous phytoplankton-oriented ecological studies have been conducted since 1965 in the extensiv... more Numerous phytoplankton-oriented ecological studies have been conducted since 1965 in the extensive North Carolina estuarine system. Throughout a range of geomorphological estuarine types, a basic underlying pattern of phytoplankton productivity and abundance following water temperature seasonal fluctuations was observed. Overlying this solar-driven pattern was a secondary forcing mechanism consisting of a complex interaction between meteorology and hydrology, resulting in periodic winter or early spring algal blooms and productivity pulses in the lower riverine estuaries. Wet winters caused abundant nitrate to reach the lower estuaries and stimulate the blooms, whereas dry winters resulted in low winter phytoplankton abundance and primary production. Dinoflagellates (Heterocapsa triquetra, Prorocen- trum minimum, Gymnodinium spp.) and various cryptomonads dominated these cool-weather estuarine blooms. Sounds were less productive than the riverine estuaries, and were dominated by dia...
Phytoplankton primary production and its environmental regulation were examined at 3 stations rep... more Phytoplankton primary production and its environmental regulation were examined at 3 stations representative of the lower Neuse River Estuary near the Pamlico Sound interface. This study covered a 3-year period (November 1987-October 1990). The authors also examined the roles of the major phytoplankton nutrients nitrogen and phosphorus in controlling growth and bloom formation. The overall potential for nuisance blooms and associated episodes of bottom water hypoxia and anoxia was investigated in field studies. Algal biomass and production varied seasonally, with high values in summer and low values in winter. In situ nutrient addition bioassays indicated the estuary experienced a general state of N limitation with especially profound limitation during summer periods. The authors recommendations for a management strategy include reductions in Dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and suspended sediment loads in order to maintain the system in a nu...
Journal of the American Statistical Association, 2019
The United States Environmental Protection Agency considers nutrient pollution in stream ecosyste... more The United States Environmental Protection Agency considers nutrient pollution in stream ecosystems one of the U.S.' most pressing environmental challenges. But limited independent replicates, lack of experimental randomization, and space-and time-varying confounding handicap causal inference on effects of nutrient pollution. In this paper the causal g-methods are extended to allow for exposures to vary in time * We would like to thank Dr. Rebecca Benner and the Nature Conservancy of North Carolina for compiling and providing the data. We would also like to thank all those who collected and collated these data in order to protect the Cape Fear watershed. The causal inference with interference research group at UNC (Brian Barkley, Sujatro Chakladar, and Wen Wei Loh) plus Mary Kirk Wilkinson provided helpful feedback and critical support throughout this project. We also thank the Associate Editor and two anonymous for helpful comments.