Cathleen Wigand | United States Environmental Protection Agency (original) (raw)
Papers by Cathleen Wigand
Frontiers in Forests and Global Change, 2021
Tropical mangrove forests have been described as “coastal kidneys,” promoting sediment deposition... more Tropical mangrove forests have been described as “coastal kidneys,” promoting sediment deposition and filtering contaminants, including excess nutrients. Coastal areas throughout the world are experiencing increased human activities, resulting in altered geomorphology, hydrology, and nutrient inputs. To effectively manage and sustain coastal mangroves, it is important to understand nitrogen (N) storage and accumulation in systems where human activities are causing rapid changes in N inputs and cycling. We examined N storage and accumulation rates in recent (1970 – 2016) and historic (1930 – 1970) decades in the context of urbanization in the San Juan Bay Estuary (SJBE, Puerto Rico), using mangrove soil cores that were radiometrically dated. Local anthropogenic stressors can alter N storage rates in peri-urban mangrove systems either directly by increasing N soil fertility or indirectly by altering hydrology (e.g., dredging, filling, and canalization). Nitrogen accumulation rates wer...
Ecological Applications, 2013
Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13... more Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13 ha/yr, and multiple stressors (e.g., wastewater inputs, dredging activities, groundwater removal, and global warming) may be contributing to marsh losses. Among these stressors, wastewater nutrients are suspected to be an important contributing cause of marsh deterioration. We used census data, radiometric dating, stable nitrogen isotopes, and soil surveys to examine the temporal relationships between human population growth and soil nitrogen; and we evaluated soil structure with computer-aided tomography, surface elevation and sediment accretion trends, carbon dioxide emissions, and soil shear strength to examine differences among disappearing (Black Bank and Big Egg) and stable marshes (JoCo). Radiometric dating and nitrogen isotope analyses suggested a rapid increase in human wastewater nutrients beginning in the late 1840s, and a tapering off beginning in the 1930s when wastewater treatment plants (WWTPs) were first installed. Current WWTPs nutrient loads to Jamaica Bay are approximately 13 995 kg N/d and 2767 kg P/d. At Black Bank, the biomass and abundance of roots and rhizomes and percentage of organic matter on soil were significantly lower, rhizomes larger in diameter, carbon dioxide emission rates and peat particle density significantly greater, and soil strength significantly lower compared to the stable JoCo Marsh, suggesting Black Bank has elevated decomposition rates, more decomposed peat, and highly waterlogged peat. Despite these differences, the rates of accretion and surface elevation change were similar for both marshes, and the rates of elevation change approximated the long term relative rate of sea level rise estimated from tide gauge data at nearby Sandy Hook, New Jersey. We hypothesize that Black Bank marsh kept pace with sea level rise by the accretion of material on the marsh surface, and the maintenance of soil volume through production of larger diameter rhizomes and swelling (dilation) of waterlogged peat. JoCo Marsh kept pace with sea-level rise through surface accretion and soil organic matter accumulation. Understanding the effects of multiple stressors, including nutrient enrichment, on soil structure, organic matter accumulation, and elevation change will better inform management decisions aimed at maintaining and restoring coastal marshes.
Springer Series on Environmental Management, 2008
Page 1. Chapter 17 Coastal Salt Marsh Community Change in Narragansett Bay in Response to Cultura... more Page 1. Chapter 17 Coastal Salt Marsh Community Change in Narragansett Bay in Response to Cultural Eutrophication Cathleen Wigand Along the Eastern Coast of North America, from the north where ice packs grate upon ...
Marine Ecology Progress Series
Decaying mats of Ulva can be washed into salt marshes by the tides as large wrack deposits, espec... more Decaying mats of Ulva can be washed into salt marshes by the tides as large wrack deposits, especially in eutrophic estuaries, where they can negatively impact marsh vegetation. Using field and laboratory experiments, we examined the effects of decomposing Ulva on Spartina alterniflora growth, soil biogeochemistry and nitrogen dynamics. High levels of Ulva exposure resulted in reductions in above-and belowground biomass, while lower levels of Ulva exposure resulted in reductions in only belowground biomass. Porewater ammonium in soil that contained decomposing Ulva quickly attained potentially toxic levels. In addition, amending soil with Ulva led to elevated porewater concentrations of sulfide and trithiane, an organosulfur compound and potential biocide. Use of a 15 N tracer documented plant uptake of Ulva-derived nitrogen, but higher nitrogen availability did not stimulate growth. Our findings support the hypothesis that decaying Ulva mats may create hotspots of adverse physiochemical conditions in salt marshes. However, because our Ulva additions were higher than typically found in coastal marshes, additional field and laboratory studies are needed to establish more firmly whether similarly adverse responses are observed under natural conditions. KEY WORDS: Salt marsh · Eutrophic estuary · Salt marsh loss · Allelochemicals · Allelopathy Resale or republication not permitted without written consent of the publisher
Tidal Marsh Restoration, 2012
Estuaries and Coasts, 2015
In the Northeastern USA, multiple anthropogenic stressors, including changing nutrient loads, acc... more In the Northeastern USA, multiple anthropogenic stressors, including changing nutrient loads, accelerated sea level rise, and altered climatic patterns, are co-occurring and are likely to influence salt marsh nitrogen (N) dynamics. We conducted a multiple-stressor mesocosm experiment to assess impacts of climate change and nutrient load on N uptake by the ecosystem dominant species. The New England salt marsh plant Spartina alterniflora was planted at mean high water (MHW) and 15 cm above and below MHW in tanks plumbed to mimic tides. The experiment consisted of two nutrient treatments (enriched, unenriched), three precipitation treatments (rain, storm, and no precipitation or control), and three elevations (low, mean, and high), with four replicate pots for each. A quarter of the way into the experiment (1 month), an N stable isotope tracer was added to a portion of the precipitation events received by the rain and storm treatments to assess how N is retained by the different components of each treatment. At the completion of the experiment, Spartina pots in the rain treatments retained far more tracer than the pots receiving the twice monthly storms, with the most tracer recovered at the highest elevation in all precipitation treatments as these pots received direct tracer input to stems and sediment surface. Experimental results suggest that the elevation of the marsh as well as the timing and delivery of rainfall may be important factors in how salt marshes intercept, retain, and transform N.
Aquatic Botany, 2015
Accelerated sea level rise threatens coastal wetland plant communities where coastal development ... more Accelerated sea level rise threatens coastal wetland plant communities where coastal development restricts transgression, and inundation increases and declining sediment supplies limit the capacity of coastal wetlands to build in elevation. Juncus gerardii Loisel., black needle rush, is a high latitude cosmopolitan plant species and, within salt marshes of the U.S. mid-Atlantic and New England coasts, it occupies a narrow belt along the marsh-upland border. Examination of historic aerial photography, vegetation resurveys, and peat composition analysis for U.S. Northeastern marshes have shown vegetation change patterns indicative of increased inundation, including decline of J. gerardii. To interpret loss patterns for J. gerardii in southern New England, we conducted a factorial experiment to establish its sensitivity to inundation and drought. A strong relationship was found between inundation and growth for J. gerardii, which together with marsh elevation and water level data, suggests that growth is reduced by current flooding patterns. Examination of J. gerardii flowering also indicates that floret and inflorescence density vary with inundation, suggesting that negative impacts of sea level rise on Juncus may extend to seed production. Late spring and summer drought impacted neither J. gerardii growth nor its flowering, implying that J. gerardii is insensitive to below-average precipitation or drought during this time of year. We conclude that current inundation patterns are incompatible with robust growth for J. gerardii, and recommend conservation actions be focused on the marsh-upland border to facilitate the upslope migration of J. gerardii and other transitional high marsh plant species.
Northeastern Naturalist, 2015
The human population and associated watershed development has risen steadily since the 1850s in R... more The human population and associated watershed development has risen steadily since the 1850s in Rhode Island. With these increases, human-derived wastewater has also risen dramatically, resulting in increasing nitrogen loads to estuarine systems. In this study, we examined relationships of modeled watershed nitrogen loads of 6 coastal subwatersheds 15 r = +0.97, P < 0.05) between the 15 N in Fundulus heteroclitus L. (Common P 15 veloped mainland marsh sites compared to less-developed island marsh sites. Our results derived from watershed wastewater sources. Furthermore, there was an inverse relationship (P = 0.05) between the modeled percentage of human wastewater and mummichog size. The increasing loads of watershed nitrogen entering into coastal salt marshes are a concern because it is unclear how well salt marsh ecosystems can continue to assimilate high nitrogen inputs especially when also subjected to a warming climate.
In the Northeastern U.S., salt marsh area is in decline. Habitat change analysis has revealed fra... more In the Northeastern U.S., salt marsh area is in decline. Habitat change analysis has revealed fragmentation, displacement of high marsh by low marsh species, and marsh drowning, while development of adjacent uplands limits upslope migration. Measures of marsh vegetation loss for eight sites in Rhode Island and New York between ca.1970 and 2011 indicate that substantial loss has occurred over past decades, with higher loss rates found for lower elevation salt marshes. Using inundation experiments, field surveys, and LiDAR datasets, we developed an elevationproductivity relationship for Spartina alterniflora specific to the U.S. Northeast, and located current salt marsh orthometric heights on this curve. We estimate that 87 % of Northeastern salt marshes are located at elevations where growth is limited by inundation. By manipulating water column nutrients, precipitation, and elevation, we further found that altered precipitation regime was associated with significant reductions in biomass, and that nutrient enrichment adversely impacts organic matter accumulation and peat formation. These results provide evidence that Northeastern U.S. marshes are vulnerable to the effects of accelerated sea level rise, and that neither precipitation changes, nor cultural eutrophication, will contribute positively to longterm salt marsh survival.
Hydrobiologia, 2000
Submerged aquatic vegetation is known as a key structural component and regulator in ecosystems. ... more Submerged aquatic vegetation is known as a key structural component and regulator in ecosystems. In this mesocosm study, we examine community- and system-level responses to the presence of Vallisneria americana (L), a deep-rooted macrophyte. Phytoplankton, bacteria and filamentous algal biomasses were significantly lowered in the presence of V. americana. In addition, mesocosms with macrophytes had significantly reduced porewater phosphate and
Successes, Limitations, and Frontiers in Ecosystem Science, 1998
Frontiers in Forests and Global Change, 2021
Tropical mangrove forests have been described as “coastal kidneys,” promoting sediment deposition... more Tropical mangrove forests have been described as “coastal kidneys,” promoting sediment deposition and filtering contaminants, including excess nutrients. Coastal areas throughout the world are experiencing increased human activities, resulting in altered geomorphology, hydrology, and nutrient inputs. To effectively manage and sustain coastal mangroves, it is important to understand nitrogen (N) storage and accumulation in systems where human activities are causing rapid changes in N inputs and cycling. We examined N storage and accumulation rates in recent (1970 – 2016) and historic (1930 – 1970) decades in the context of urbanization in the San Juan Bay Estuary (SJBE, Puerto Rico), using mangrove soil cores that were radiometrically dated. Local anthropogenic stressors can alter N storage rates in peri-urban mangrove systems either directly by increasing N soil fertility or indirectly by altering hydrology (e.g., dredging, filling, and canalization). Nitrogen accumulation rates wer...
Ecological Applications, 2013
Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13... more Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13 ha/yr, and multiple stressors (e.g., wastewater inputs, dredging activities, groundwater removal, and global warming) may be contributing to marsh losses. Among these stressors, wastewater nutrients are suspected to be an important contributing cause of marsh deterioration. We used census data, radiometric dating, stable nitrogen isotopes, and soil surveys to examine the temporal relationships between human population growth and soil nitrogen; and we evaluated soil structure with computer-aided tomography, surface elevation and sediment accretion trends, carbon dioxide emissions, and soil shear strength to examine differences among disappearing (Black Bank and Big Egg) and stable marshes (JoCo). Radiometric dating and nitrogen isotope analyses suggested a rapid increase in human wastewater nutrients beginning in the late 1840s, and a tapering off beginning in the 1930s when wastewater treatment plants (WWTPs) were first installed. Current WWTPs nutrient loads to Jamaica Bay are approximately 13 995 kg N/d and 2767 kg P/d. At Black Bank, the biomass and abundance of roots and rhizomes and percentage of organic matter on soil were significantly lower, rhizomes larger in diameter, carbon dioxide emission rates and peat particle density significantly greater, and soil strength significantly lower compared to the stable JoCo Marsh, suggesting Black Bank has elevated decomposition rates, more decomposed peat, and highly waterlogged peat. Despite these differences, the rates of accretion and surface elevation change were similar for both marshes, and the rates of elevation change approximated the long term relative rate of sea level rise estimated from tide gauge data at nearby Sandy Hook, New Jersey. We hypothesize that Black Bank marsh kept pace with sea level rise by the accretion of material on the marsh surface, and the maintenance of soil volume through production of larger diameter rhizomes and swelling (dilation) of waterlogged peat. JoCo Marsh kept pace with sea-level rise through surface accretion and soil organic matter accumulation. Understanding the effects of multiple stressors, including nutrient enrichment, on soil structure, organic matter accumulation, and elevation change will better inform management decisions aimed at maintaining and restoring coastal marshes.
Springer Series on Environmental Management, 2008
Page 1. Chapter 17 Coastal Salt Marsh Community Change in Narragansett Bay in Response to Cultura... more Page 1. Chapter 17 Coastal Salt Marsh Community Change in Narragansett Bay in Response to Cultural Eutrophication Cathleen Wigand Along the Eastern Coast of North America, from the north where ice packs grate upon ...
Marine Ecology Progress Series
Decaying mats of Ulva can be washed into salt marshes by the tides as large wrack deposits, espec... more Decaying mats of Ulva can be washed into salt marshes by the tides as large wrack deposits, especially in eutrophic estuaries, where they can negatively impact marsh vegetation. Using field and laboratory experiments, we examined the effects of decomposing Ulva on Spartina alterniflora growth, soil biogeochemistry and nitrogen dynamics. High levels of Ulva exposure resulted in reductions in above-and belowground biomass, while lower levels of Ulva exposure resulted in reductions in only belowground biomass. Porewater ammonium in soil that contained decomposing Ulva quickly attained potentially toxic levels. In addition, amending soil with Ulva led to elevated porewater concentrations of sulfide and trithiane, an organosulfur compound and potential biocide. Use of a 15 N tracer documented plant uptake of Ulva-derived nitrogen, but higher nitrogen availability did not stimulate growth. Our findings support the hypothesis that decaying Ulva mats may create hotspots of adverse physiochemical conditions in salt marshes. However, because our Ulva additions were higher than typically found in coastal marshes, additional field and laboratory studies are needed to establish more firmly whether similarly adverse responses are observed under natural conditions. KEY WORDS: Salt marsh · Eutrophic estuary · Salt marsh loss · Allelochemicals · Allelopathy Resale or republication not permitted without written consent of the publisher
Tidal Marsh Restoration, 2012
Estuaries and Coasts, 2015
In the Northeastern USA, multiple anthropogenic stressors, including changing nutrient loads, acc... more In the Northeastern USA, multiple anthropogenic stressors, including changing nutrient loads, accelerated sea level rise, and altered climatic patterns, are co-occurring and are likely to influence salt marsh nitrogen (N) dynamics. We conducted a multiple-stressor mesocosm experiment to assess impacts of climate change and nutrient load on N uptake by the ecosystem dominant species. The New England salt marsh plant Spartina alterniflora was planted at mean high water (MHW) and 15 cm above and below MHW in tanks plumbed to mimic tides. The experiment consisted of two nutrient treatments (enriched, unenriched), three precipitation treatments (rain, storm, and no precipitation or control), and three elevations (low, mean, and high), with four replicate pots for each. A quarter of the way into the experiment (1 month), an N stable isotope tracer was added to a portion of the precipitation events received by the rain and storm treatments to assess how N is retained by the different components of each treatment. At the completion of the experiment, Spartina pots in the rain treatments retained far more tracer than the pots receiving the twice monthly storms, with the most tracer recovered at the highest elevation in all precipitation treatments as these pots received direct tracer input to stems and sediment surface. Experimental results suggest that the elevation of the marsh as well as the timing and delivery of rainfall may be important factors in how salt marshes intercept, retain, and transform N.
Aquatic Botany, 2015
Accelerated sea level rise threatens coastal wetland plant communities where coastal development ... more Accelerated sea level rise threatens coastal wetland plant communities where coastal development restricts transgression, and inundation increases and declining sediment supplies limit the capacity of coastal wetlands to build in elevation. Juncus gerardii Loisel., black needle rush, is a high latitude cosmopolitan plant species and, within salt marshes of the U.S. mid-Atlantic and New England coasts, it occupies a narrow belt along the marsh-upland border. Examination of historic aerial photography, vegetation resurveys, and peat composition analysis for U.S. Northeastern marshes have shown vegetation change patterns indicative of increased inundation, including decline of J. gerardii. To interpret loss patterns for J. gerardii in southern New England, we conducted a factorial experiment to establish its sensitivity to inundation and drought. A strong relationship was found between inundation and growth for J. gerardii, which together with marsh elevation and water level data, suggests that growth is reduced by current flooding patterns. Examination of J. gerardii flowering also indicates that floret and inflorescence density vary with inundation, suggesting that negative impacts of sea level rise on Juncus may extend to seed production. Late spring and summer drought impacted neither J. gerardii growth nor its flowering, implying that J. gerardii is insensitive to below-average precipitation or drought during this time of year. We conclude that current inundation patterns are incompatible with robust growth for J. gerardii, and recommend conservation actions be focused on the marsh-upland border to facilitate the upslope migration of J. gerardii and other transitional high marsh plant species.
Northeastern Naturalist, 2015
The human population and associated watershed development has risen steadily since the 1850s in R... more The human population and associated watershed development has risen steadily since the 1850s in Rhode Island. With these increases, human-derived wastewater has also risen dramatically, resulting in increasing nitrogen loads to estuarine systems. In this study, we examined relationships of modeled watershed nitrogen loads of 6 coastal subwatersheds 15 r = +0.97, P < 0.05) between the 15 N in Fundulus heteroclitus L. (Common P 15 veloped mainland marsh sites compared to less-developed island marsh sites. Our results derived from watershed wastewater sources. Furthermore, there was an inverse relationship (P = 0.05) between the modeled percentage of human wastewater and mummichog size. The increasing loads of watershed nitrogen entering into coastal salt marshes are a concern because it is unclear how well salt marsh ecosystems can continue to assimilate high nitrogen inputs especially when also subjected to a warming climate.
In the Northeastern U.S., salt marsh area is in decline. Habitat change analysis has revealed fra... more In the Northeastern U.S., salt marsh area is in decline. Habitat change analysis has revealed fragmentation, displacement of high marsh by low marsh species, and marsh drowning, while development of adjacent uplands limits upslope migration. Measures of marsh vegetation loss for eight sites in Rhode Island and New York between ca.1970 and 2011 indicate that substantial loss has occurred over past decades, with higher loss rates found for lower elevation salt marshes. Using inundation experiments, field surveys, and LiDAR datasets, we developed an elevationproductivity relationship for Spartina alterniflora specific to the U.S. Northeast, and located current salt marsh orthometric heights on this curve. We estimate that 87 % of Northeastern salt marshes are located at elevations where growth is limited by inundation. By manipulating water column nutrients, precipitation, and elevation, we further found that altered precipitation regime was associated with significant reductions in biomass, and that nutrient enrichment adversely impacts organic matter accumulation and peat formation. These results provide evidence that Northeastern U.S. marshes are vulnerable to the effects of accelerated sea level rise, and that neither precipitation changes, nor cultural eutrophication, will contribute positively to longterm salt marsh survival.
Hydrobiologia, 2000
Submerged aquatic vegetation is known as a key structural component and regulator in ecosystems. ... more Submerged aquatic vegetation is known as a key structural component and regulator in ecosystems. In this mesocosm study, we examine community- and system-level responses to the presence of Vallisneria americana (L), a deep-rooted macrophyte. Phytoplankton, bacteria and filamentous algal biomasses were significantly lowered in the presence of V. americana. In addition, mesocosms with macrophytes had significantly reduced porewater phosphate and
Successes, Limitations, and Frontiers in Ecosystem Science, 1998