Acidic Wetlands Research Articles

Tidally driven water column hydro-geochemistry in a remediating acidic wetland

Managed tidal inundation is a newly evolved technique for remediating coastal acid sulphate soil (CASS) wetlands. However, there remains considerable uncertainty regarding the hydro-geochemical pathways and spatiotemporal dynamics of residual H+ and metal(loid) mobilisation into the tidal fringe surface waters of these uniquely iron-rich landscapes. Here, we examine the hydrology and water column chemistry across the intertidal slope of a remediating CASS wetland during several tide cycles. There was extreme spatial and temporal dynamism in water column chemistry, with pH fluctuating by ∼3 units (∼3.5–6.5) during a single tide cycle. Acute acidity was spatially confined to the upper intertidal slope, reflecting surface sediment properties, and tidal overtopping is an important pathway for mobilisation of residual H+ and Al3+ to the water column. Marine derived HCO3- was depleted from surface waters migrating across the intertidal slope and a strong gradient in HCO3- was observed from the tidal fringe to the adjacent tributary channel and nearby estuary. Tidal forcing generated oscillating hydraulic gradients in the shallow fringing aquifer, favouring ebb-tide seepage and driving rapid, heterogeneous advection of groundwater on the lower intertidal slope via surface connected macropores. A combination of diffusive and advective flux across the sediment–water interface led to persistent, elevated surface water Fe2+ (∼10–1000 μM). The geochemical processes associated with Fe2+ mobilisation displayed distinct spatial zonation, with low pH, proton-promoted desorption occurring on the upper intertidal slope, whilst circum-neutral pH, Fe(III)-reducing processes dominated the lower intertidal slope. Arsenic was also mobilised into surface waters on the lower intertidal slope under moderate pH (∼6.0) conditions and was strongly positively correlated with Fe2+. Saturation index values for aragonite were substantially depressed (−1 to −5) and significantly negatively correlated with elevation, thereby presenting a barrier to re-colonisation of the upper intertidal slope by calcifying benthic organisms. These findings highlight the spatially complex hydrological and geochemical controls on surface water quality that can occur in tidally inundated acid sulphate soil environments.

Mercury in swamp sparrows (Melospiza georgiana) from wetland habitats in Wisconsin

Wetlands play a major role in the export of methylmercury (MeHg) to a watershed. The large contribution of wetlands to watersheds in northern Wisconsin, coupled with the acidic environment of this area, makes these habitats especially vulnerable to mercury (Hg) accumulation by biota. The purpose of this study was to compare Hg accumulation between northern Wisconsin wetlands and southern Wisconsin wetlands using the swamp sparrow (Melospiza georgiana) as a representative species. The swamp sparrow was selected as a representative passerine species in which to examine Hg in these habitats, because during their breeding season, they feed at a higher trophic level than many of their counterparts. During the breeding seasons of 2007 and 2008, blood samples were collected from swamp sparrows inhabiting wetlands in both northern and southern Wisconsin and analyzed for total Hg. The mean concentration of total Hg in swamp sparrows from northern wetlands was 0.135 ± 0.064 μg/ml while the mean concentration of total Hg in swamp sparrows from southern wetlands was 0.187 ± 0.106 μg/ml. Results revealed no significant difference (P = 0.17) between Hg accumulation in swamp sparrows from less-acidic wetlands in southern Wisconsin and Hg in swamp sparrows from acidic wetlands in northern Wisconsin. The results are contrary to those observed in other species such as common loon, tree swallow and river otter where higher accumulation has been observed in individuals from acidic habitats. Reasons for the lack of this accumulation pattern in swamp sparrows are unclear and warrant further study.

Microbial diversity of active layer and permafrost in an acidic wetland from the Canadian High Arctic

The abundance and structure of archaeal and bacterial communities from the active layer and the associated permafrost of a moderately acidic (pH < 5.0) High Arctic wetland (Axel Heiberg Island, Nunavut, Canada) were investigated using culture- and molecular-based methods. Aerobic viable cell counts from the active layer were ∼100-fold greater than those from the permafrost (2.5 × 10(5) CFU·(g soil dry mass)(-1)); however, a greater diversity of isolates were cultured from permafrost, as determined by 16S rRNA gene sequencing. Isolates from both layers demonstrated growth characteristics of a psychrotolerant, halotolerant, and acidotolerant community. Archaea constituted 0.1% of the total 16S rRNA gene copy number and, in the 16S rRNA gene clone library, predominantly (71% and 95%) consisted of Crenarchaeota related to Group I. 1b. In contrast, bacterial communities were diverse (Shannon's diversity index, H = ∼4), with Acidobacteria constituting the largest division of active layer clones (30%) and Actinobacteria most abundant in permafrost (28%). Direct comparisons of 16S rRNA gene sequence data highlighted significant differences between the bacterial communities of each layer, with the greatest differences occurring within Actinobacteria. Comparisons of 16S rRNA gene sequences with those from other Arctic permafrost and cold-temperature wetlands revealed commonly occurring taxa within the phyla Chloroflexi, Acidobacteria, and Actinobacteria (families Intrasporangiaceae and Rubrobacteraceae).

Vulnerability of organic acid tolerant wetland biota to the effects of inorganic acidification

Inland waterbodies are often naturally acidic but are these ecosystems pre-adapted to inorganic acidification e.g., by acid sulfate soils (ASS)? We conducted a controlled mesocosm experiment with inorganically acidified wetland water and wetland sediment replicates to pH 3 from a naturally acidic (pH 3.9, conductivity=74µScm−1) wetland in south-western Australia. Following acidification, dissolved organic carbon and nitrogen declined, and chlorophyll a dropped to zero. Inorganic acidification mobilised metals from sediment sods with increased water concentrations of Cu, Fe, Mn, Ca, Mg and Al. Acidification showed no significant effect on diatom assemblage. Nonetheless, greatly reduced abundance and diversity of grazing zooplankton was observed. Macroinvertebrates generally showed abundance decreases, although filterer–collector taxa increased. Decreased primary production reduced functional diversity and consumer biomasses. These results suggest likely impact to ecosystem functioning of low pH, weakly-buffered and stained wetlands if exposed to inorganic acidification.

Exploring methanotroph diversity in acidic northern wetlands: Molecular and cultivation-based studies

Acidic wetlands of the northern hemisphere are an important source of methane, a major greenhouse gas. The taxonomic identity of the aerobic methanotrophic bacteria, which colonize these environments and reduce the potential flux of methane to the atmosphere, has remained elusive for a long time. Both cultivation-independent molecular approaches and cultivation-based studies have been used to identify methanotrophs in this acidic habitat. It was shown that acidic peat is colonized mainly by methanotrophic representatives of the Alphaproteobacteria: Methylocystis spp., Methylocella spp. and Methylocapsa spp. Novel methanotrophic isolates from acidic wetlands display a number of unique characteristics and metabolic traits including unusual cell ultrastructure and fatty acid composition, ability to utilize some multicarbon compounds as growth substrates, and new regulatory mechanisms of methane oxidation. Several other methanotroph populations, which have been detected in acidic peat by molecular approaches but have so far eluded isolation, represent a challenge for further cultivation studies.

Intermediary ecosystem metabolism as a main driver of methanogenesis in acidic wetland soil

Methanogens have a very limited substrate range, and their in situ activities are thus linked to 'intermediary ecosystem metabolism', i.e. complex trophic interactions with other microorganisms catalysing essential intermediary processes that ultimately drive methanogenesis. However, information on intermediary ecosystem metabolism and associated biota is fragmented and often conceptualized rather than resolved. The main objective of this review is to evaluate the concept of intermediary ecosystem metabolism in context with recent work aimed at resolving the complex trophic interactions of a methane-emitting peatland.

The effects of changes in soil moisture on nitrogen cycling in acid wetland types of the New Jersey Pinelands (USA)

Wetlands are subject to changes in soil moisture as a result of both short-term seasonal climate variations and long-term changes in regional water resource management, both of which can modify the dynamics of ground and surface water inputs. In the New Jersey Pinelands, forested wetlands that differ in both plant communities and soil structure occur along a topographic and hydrological gradient associated with an unconfined aquifer. Proposed groundwater withdrawals may affect water content of soils along this gradient. We hypothesized that prolonged changes in soil moisture would alter net nitrogen mineralization and nitrification rates in proportion to the amount of moisture change, and that these changes would be similar for the different soils along the drainage catena. Soils from two catenary sequences of wetlands, including pine-dominated (driest landscape position), hardwood-dominated, and Atlantic white-cedar-dominated (wettest landscape position) communities were used in long-term laboratory incubations (36 weeks). Production of NH 4 +–N, NO 3 −–N, and dissolved organic N were measured under two sets of conditions: constant moisture levels of 100%, 60% and 30% water-holding capacity (WHC), and fluctuating moisture levels (alternating 2 week periods at 100% and 30% WHC). In soils from most of the wetlands, we observed increases in net mineralization and nitrification when constant low-moisture conditions were established, but not under fluctuating conditions. Contrary to expectations, responses to the drying treatments varied between wetland types and between replicate wetlands of each type. Under constant-moisture conditions, nitrification increased more in cedar swamps than in either type of pine wetland. Under all conditions, soils from all the wetlands within one of the catenas produced more inorganic and organic soluble N than did the wetlands from the other catena, suggesting that area-wide effects are as important as wetland type in regulating production of soluble N. Within both catenas, pine-hardwood wetlands generated more soluble N under all moisture conditions than did either pine-dominated or cedar wetlands. Our results suggest that changes in soil moisture due to management of water resources will affect N cycling in wetland soils, but that the magnitude of the effects, and the potential for large releases of nitrate, will depend on the specific soil properties of affected wetlands.

Changes in nutrient availability from calcareous to acid wetland habitats with closely related brown moss species: increase instead of decrease in N and P

To test whether shifts in nutrient availability from calcareous to mineral-poor habitats could be a driving force in the evolution of seven closely related wetland brown mosses, we measured soil and vascular plant nutrients and conducted a laboratory incubation experiment with Swedish and some Dutch samples, in which net N and P-mineralization, respiration and microbial characteristics were measured. In spite of high respiration and microbial N, net N-mineralization appeared to be low for the calcareous Palustriella falcata and Scorpidium spp. Net N-mineralization significantly increased (and respiration and microbial N decreased) for the mineral-poor Sarmentypnum exannulatum, Straminergon stramineum and Warnstorfia fluitans, probably due to a decrease in microbial N-demand. Even though values were mainly negative, net P-mineralization showed a similar increase from calcareous to mineral-poor fens, probably due to lower precipitation of calcium phosphate. The calcareous habitat of the early wetland mosses may thus have been nutrient-poor instead of nutrient-rich. Adaptation to mineral-poor habitats, probably driven by expansion of mineral-poor wetlands when the boreal zone became colder and wetter, may have been associated with higher availability of ammonium and phosphate. However, this may have stimulated Sphagnum more than brown mosses, which may have been restricted to particular niches with perhaps some nitrification.

Singulisphaera acidiphila gen. nov., sp. nov., a non-filamentous, Isosphaera-like planctomycete from acidic northern wetlands

Four novel strains of budding bacteria, designated MOB10T, PO2, MPL1015 and BG32, were isolated from acidic wetlands of northern Russia. Cells of these four strains were aerobic, non-motile spheres that occurred singly or in shapeless aggregates and attached to surfaces by means of a holdfast material. The isolates were moderately acidophilic, mesophilic organisms capable of growth between pH 4.2 and 7.5 (optimum growth at pH 5.0-6.2) and at temperatures between 4 and 33 degrees C (optimum growth at 20-26 degrees C). The strains possessed a complex intracellular membrane system that compartmentalized the cells. The major fatty acids were C16 : 0, C18 : 1omega9c and C18 : 2omega6c,12c. The major quinone was menaquinone-6 (MK-6). The G+C content of the DNA was 57.8-59.9 mol%. 16S rRNA gene sequence analysis showed that strains MOB10T, PO2, MPL1015 and BG32 were members of the order Planctomycetales and belonged to a phylogenetic lineage defined by the genus Isosphaera, exhibiting 90 % sequence similarity to the type strain of the thermophilic planctomycete Isosphaera pallida and 95-95.5 % sequence similarity to a taxonomically uncharacterized group of filamentous bacteria from activated sludge, 'Nostocoida limicola' III. However, compared with 'Nostocoida limicola' III and Isosphaera pallida, the new isolates from acidic wetlands were non-filamentous, unpigmented bacteria, which possessed highly distinctive phospholipid fatty acid profiles and were capable of growth and of degrading several biopolymers under acidic, microaerobic and cold conditions. The data suggest that the four isolates should be considered as representing a novel species of a new genus of the order Planctomycetales, for which the name Singulisphaera acidiphila gen. nov., sp. nov. is proposed. The type strain of Singulisphaera acidiphila is MOB10T (=ATCC BAA-1392T =VKM B-2454T =DSM 18658T).

Effects of groundwater extraction from crystalline hard rock on water chemistry in an acid forested catchment at Gårdsjön, Sweden

Atmospheric deposition of S in Sweden has decreased by some 80% over the last 15 a, resulting in a general reduction of SO 4 concentrations in ground and surface water. This project, however, shows that artificial hydrological alteration in an acid wetland can reverse this trend and increase acidity and SO 4 concentrations. The experiment involved the monitoring of two catchments in relatively virgin conditions. In one of the catchments, an experiment with intensive groundwater extraction from the bedrock was carried out. During the experiment, the runoff from the catchment decreased by 50%. Furthermore, the extraction of groundwater resulted in increased seasonal aeration of the centrally located wetland, leading to oxidation of reduced S bound to the soil layers of the wetland. The S changed to solute SO 4, with a subsequent SO 4 surge. Thus, the experiment resulted in an induced acidification of the wetland and runoff waters. The extraction of groundwater significantly increased the recharge of water from the overburden, glacial till and organic soils to groundwater in the bedrock, which in turn reduced the retention time in the bedrock aquifer. These changes resulted in the chemical signature of the groundwater in the bedrock becoming similar to those of the wetland. The findings revealed deterioration in the water quality in the bedrock due to increased concentrations of dissolved organic C and SO 4, as well as a decrease in pH.

The Effects of pH on a Periphyton Community in an Acidic Wetland, USA

The Effects of pH on a Periphyton Community in an Acidic Wetland, USA

Effect of Soil Type, Applications of Chicken Manure and Effective Microorganisms on Corn Yield and Microbial Properties of Acidic Wetland Soils in Indonesia

A field experiment was carried out to elucidate the effect of chicken manure (CM) and effective microorganisms (EM) on the yield of corn and chemical and microbial properties of acidic wetland soils. A split-split plot experimental design with three replications was used in this research. The main plot consisted of two types of soil. The sub-plot was for the application of CM, while the sub-sub plot was for the application of EM. Sweet corn seeds were planted and cultivated until harvest. Above ground plant biomass and round of the stem of an ear of corn were observed. Soil samples were taken and analyzed for chemical and microbial properties. The results showed that the interaction between soil types and CM application affected the corn yield, while EM had no effect. Similarly, the chemical and microbial characteristics of soils used were affected by soil type and the application of CM, while the effect of EM was not clear.

Facultative Methanotrophs Revisited

Facultative Methanotrophs Revisited

Mercury dynamics of a temperate forested wetland

Wetlands have been identified as important sites of mercury methylation in catchments, but the range of wetland types and their geographic distribution for which methylmercury fluxes are reported in the literature are limited. Linkages among wetland hydrology, total mercury and methylmercury concentrations and fluxes, and other water quality parameters were assessed in a temperate forested swamp in Southern Ontario, Canada. Two hydrogeomorphically distinct stream reaches within the wetland exhibited differences in wetland-stream hydrologic connectivity, which strongly influenced mercury dynamics. Total mercury flux from both reaches to the downstream was highest during flow conditions in which the wetland and stream were hydrologically connected. The wetland as a whole was a net sink for total mercury and a net source for methylmercury to the downstream system. Both total mercury and methylmercury concentrations were related to dissolved and particulate organic carbon in stream waters, but these relationships were dependent upon the sampling location and flow conditions. Throughout the wetland, methylmercury concentrations exhibited temporal relationships with sulfate concentrations. Further, despite short surface water residence times, periods of wetland and stream disconnect and high pH (approx. 8) in surface water, methylmercury fluxes from this wetland to the downstream were similar to those from more stagnant and acidic wetlands.

Insect faunas associated with the Fossil remains of Pinus sylvestris L. in blanket peat from Northeast Scotland

Pine stumps have been found preserved in blanket peats at altitudes of up to 793 m OD in Scotland. Radiocarbon dating by other researchers has demonstrated that these sites were not all contemporary, but most fall within the mid‐Holocene period. Palynological, dendrochronological and stable isotope analyses have previously been carried out on these fossil pine stumps, but not palaeoentomological analysis. This paper reports on the results of an analysis of the fossil beetle remains from two of these sites in the Cairngorms, Monaltrie Moss and a moss on the Mar Lodge estate. The insect faunas indicate that acidic wetland was colonised by pine trees, which developed into mature woodland. The dominance of saproxylic (deadwood) faunas in comparison to those associated with healthier trees suggests that the woodland was always under stress. The pine fauna at Mar Lodge was replaced by montane wetland species once the pine trees died out.

Isolation of acidophilic methane-oxidizing bacteria from northern peat wetlands.

Acidic northern wetlands are an important source of methane, one of the gases that contributes to global warming. Methane oxidation in the surface of these acidic wetlands can reduce the methane flux to the atmosphere up to 90 percent. Here the isolation of three methanotrophic microorganisms from three boreal forest sites is reported. They are moderately acidophilic organisms and have a soluble methane monooxygenase. In contrast to the known groups of methanotrophs, 16S ribosomal DNA sequence analysis shows that they are affiliated with the acidophilic heterotrophic bacterium Beijerinckia indica subsp. indica.

Hypohelion scirpinum . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Hypohelion scirpinum . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Hypohelion scirpinum usually occurs on dead fallen stems and leaves of Schoenoplectus lacustris . Virtually nothing is known about the ecology of this fungus, except for Ingold's observation that its life cycle is entirely aquatic. It seems likely however that, like many other members of the Rhytismataceae , the fungus colonizes the living plant, then fruits on those leaves and stems after they have died. HOSTS: Arundinaria macrosperma (stem), Plantae gen. indet. (leaf), Schoenoplectus lacustris (stem, dead floating stem), Scirpus lacustris var. occidentalis (stem), S. validus (stem), Scirpus sp. (stem). Almost all records are from Schoenoplectus lacustris , many of the others are misidentifications or synonyms for this plant. The record on Arundinaria is questionable. GEOGRAPHICAL DISTRIBUTION: Belgium, Canada (Saskatchewan), France, Germany, Hungary, Italy, Latvia, Russia (Tver Oblast), Sweden, UK (England), Ukraine, USA (Dakota, Mississippi). A temperate northern hemisphere species of low altitude, not very acidic wetlands and slow flowing rivers. Rather infrequently recorded, with numbers of records declining, and some unsuccessful searches for this fungus in apparently suitable habitats in recent years. TRANSMISSION: By air-borne ascospores in humid conditions.

Fungal endophytes from the roots of alpine and boreal Ericaceae

Oidiodendron mains Barron, Scytalidiutn vaccinii Dalpé, Litten, &amp; Sigler, and a variable white taxon (VWT) were isolated consistently from the roots of ericaceous plants collected in three different habitats. Restriction fragment length polymorphism data were used to (i) clarify the identification of strains of O. maius with character states intermediate between O. maius and Oidiodendron griseum Robak, (ii) identify the VWT as distinct from S. vaccinii in spite of cultural similarities, and (iii) reveal that S. vaccinii comprises two genotypes correlated with habitat. Corn meal agar was used to induce conidiogenesis in S. vaccinii, and one strain produced apothecia consistent with the description of Hymenoscyphus ericae (Read) Korf &amp; Kernan, confirming the anamorph–teleomorph relationship of these two taxa. Oidiodendron maius and S. vaccinii, already accepted as mycobionts of the Ericaceae, are confirmed as ubiquitous in natural habitats of Alberta and are often both isolated from the same root fragment. The isolation of Phialocephala fortinii Wang &amp; Wilcox, a non-mycorrhizal endophyte of diverse plant families, from two of the sites but not from the acidic wetland indicates that its distribution depends on edaphic factors. Its vigorous growth on the initial isolation plates adversely affected the recovery of the other three taxa. Key words: ericoid mycorrhiza, Ericaceae, RFLP, Oidiodendron, Scytalidium, Hymenoscyphus, Phialocephala.

Hydrologic control of sulfur biogeochemistry in an acidic freshwater wetland

(1994). Hydrologic control of sulfur biogeochemistry in an acidic freshwater wetland. SIL Proceedings, 1922-2010: Vol. 25, No. 3, pp. 1311-1314.

Partitioning of lead in pristine and runoff-impacted waters from acidic wetlands in the New Jersey Pinelands

We have examined the roles of dissolved organic carbon (DOC) and pH in determining patterns of Pb fractionation in surface water from Sphagnum-dominated peatlands in undisturbed and urbanized watersheds of the Pinelands of New Jersey. In undisturbed wetlands, the water is highly acidic (pH 3.5) and has high concentrations of DOC; wetlands receiving urban runoff are less acidic and have lower concentrations of DOC. The effects of PH were separated from the effects of DOC by experimentally raising the pH of water from the undisturbed site to 6.0. A separation procedure was compiled from the literature to separate the soluble Pb fraction into labile (exchangeable on ion-exchange resin) and non-labile fractions, and the latter fraction was further separated into photo-oxidation-sensitive and insensitive fractions. In low pH, high DOC waters, 95% of added PbCl2 remained soluble, and 56 to 80% of this Pb was labile (varying with contact time with the resin). In high-pH swamp waters, a smaller fraction (64 to 71%) remained soluble; the distribution of the soluble Pb among non-labile forms varied with the source of the water. Pb fractionation in runoff was quite different from that in runoff-impacted swamp water at the same pH, and may reflect differences in DOC and/or higher levels of Fe in the runoff.