Wetlands

Two new species of Nitzschia (Bacillariophyta) from shallow wetlands of Peninsular India

by Karthick Balasubramanian

The majority of species belonging to the genus Nitzschia are distinguished by minute taxonomic features that are... more The majority of species belonging to the genus Nitzschia are distinguished by minute taxonomic features that are difficult to observe and document. Currently, geographical distributions for many species are recognized as cosmopolitan; in contrast endemic species are poorly documented and studied. Our study describes two new species of Nitzschia from shallow wetlands across the Bangalore urban district of peninsular India, Nitzschia taylorii, sp. nov. and Nitzschia williamsi, sp. nov. Morphological analyses of these new species were performed with light and scanning electron microscopy, and the ecology of inhabited wetlands are discussed briefly. New species records from urban polluted wetlands provide evidence for broadening taxonomic and ecological investigations of cosmopolitan genera like Nitzschia in the Southern Hemisphere.

Why Should We Care About Birds? By Carol P. Christ

by Feminism and Religion

Originally published on the Feminism and Religion project

I believe that we should we care about birds because it is right to do so.  If we do not, we will contribute to... more I believe that we should we care about birds because it is right to do so.  If we do not, we will contribute to extinction of species, and we will leave a diminished world to those who come after us. We must not give up hope that we can save the world for birds, for other wildlife, and for our children’s children.

On February 2, 2012, the International Day for Wetlands, the Greek government signed into law a Presidential Directive mandating protection of the small wetlands of the Greek islands.  There is no assurance that this law will be enforced.  There are still no measures in effect to protect most of the larger wetlands in Greece, even though this is required by the European law Natura 2000, which requires all of the countries in the European Union to protect bird and wildlife habitats.

Controls on in situ oxygen and DIC dynamics in peats of a temperate fen

by Klaus-Holger Knorr

By Cristian Estop-Aragones, Klaus-Holger Knorr, and Christian Blodau

Rapid Mapping and Prioritisation of Wetland Sites in the Manawatu–Wanganui Region, New Zealand

by Anne-Gaelle Ausseil

Applying systematic conservation planning principles to palustrine and inland saline wetlands of New Zealand: Wetlands systematic conservation planning

by Anne-Gaelle Ausseil

Hydrological and Water Quality Characterisation of a Tropical Riverine Wetland: Nabajjuzi-Masaka, Uganda

by Najib Lukooya Bateganya

Abstract
In East Africa where wetlands are becoming essential systems for waste water treatment and potable... more Abstract
In East Africa where wetlands are becoming essential systems for waste water treatment and potable water supply, hydrological characterisation is crucial to understand the dynamics of their functioning on a spatial and temporal scale. Beside ecosystem services, basic ecological properties such as vegetation structure and nutrient cycling of wetland ecosystems depend on hydrology. Nabajjuzi wetland, in central Uganda, East Africa is internationally recognised as a Ramsar site and currently used for potable water supply in addition to other essential ecological and social economic services to the riparian communities. To contribute to the limited and scanty information of this ecosystem, the study focussed on hydrological and water quality characterisation using a water-nutrient mass balance as the major output. Also, the flow dynamics of Fe and allochthonous suspended solids loading into the wetland were investigated.

Results show that the water balance of Nabajjuzi wetland is dominated by surface flow, which is influenced by rainy and dry periods. During peak flow, the estimated hydraulic retention time was found to be 1 month compared to 1.5 months during the low flow period. Also, water loss flux due to evapotranspiration in this region is high and in Nabajjuzi wetland, it is twice the daily rate of abstraction. Analysis of long term flow data also revealed that the current water abstraction rate can potentially result in hydrological stress to the system during extremely low flow periods. However, the wetland N and P loading is very low compared to other urban disturbed wetlands. Consequently, high concentration of Fe and suspended solids loading are the major constraints to the surface water quality hence potable water supply. Generally, there is need for a more comprehensive hydrological-water quality study and careful planning of the future catchment land use strategies. This can enhance management and conservation of the wetland to guarantee the crucial ecosystem services it provides.

Keywords: Hydrology, Riverine wetland, Hydrological gradient, Surface-flow, Nutrients, Iron, Mass-balance, Lake Victoria basin.

Nitrogen removal from landfill leachate in constructed wetlands with reed and willow: Redox potential in the root zone

by Antonio Albuquerque

A. Białowiec, L. Davieis, A. Albuquerque, P. Randerson
Journal of Environmental Management, 2012, V. 97, 22–27

This study investigated the effects of reed and willow on bioremediation of landfill leachate in comparison with an... more This study investigated the effects of reed and willow on bioremediation of landfill leachate in comparison with an unplanted control by measuring redox potential levels in the rhizosphere of microcosm systems in a greenhouse. Plants had a significant influence on redox potential relative to the plant-less system. Redox potential in the reed rhizosphere was anoxic (mean −102 ± 85 mV), but it was the least negative, being significantly higher than in the willow (mean −286 ± 118 mV), which had the lowest Eh. Redox potential fluctuated significantly in the willow rhizosphere during daylight hours, with large decreases in the morning. Levels of NH4+ decreased significantly in the first day of the experiment and remained at similar low levels in all three variants for the next four weeks of the experiment. Following this removal of ammonia significant peaks in NO2− occurred in the control and reed tanks on the 1st day, and again on 14th day in the control tank up to 13 mg/dm3. In the willow tank there was also one significant peak of NO2− in the first week, but only up to 0.5 mg/dm3. Significant accumulation, within 21 days of NO3− in all variants was observed, but in tanks with reed and willow the concentration of NO3− remained significantly lower (<4 mg/dm3) than in the unplanted tank (∼35 mg/dm3). Final levels of total-nitrogen, nitrate and chemical oxygen demand were considerably lower in the reed and willow tank than in the unplanted tank.

The influence of plants on nitrogen removal from landfill leachate in discontinuous batch shallow constructed wetland with recirculating subsurface horizontal flow

by Antonio Albuquerque

A. Białowiec, L. Davies, A. Albuquerque, P. Randerson
Ecological Engineering, 2012, V. 40, 44-52

Three discontinuous batch shallow constructed wetland systems with recirculating subsurface horizontal flow with reed,... more Three discontinuous batch shallow constructed wetland systems with recirculating subsurface horizontal flow with reed, willow, and without plants were used to assess the removal of nitrogen from landfill leachate in relation to hydraulic retention time and climatic conditions. In all systems redox potential in the beds increased asymptotically from negative anoxic conditions to +67 (reed bed), −2 (willow bed), and +17 mV (control bed), reaching a plateau in two wk. During the first 24 h after feeding the beds all forms of nitrogen decreased significantly. It has been shown that plants release O2 and Norg which was then hydrolyzed to ammonia. Plant-available radiation significantly (p < 0.05) increased the release of Norg and removal of ammonia after the 9th day of the experiment. Low, and relatively constant concentrations of nitrite and nitrate indicated that denitrification had taken place in the beds.

Influence of stormwater infiltration on the treatment capacity of a LECA-based horizontal subsurface flow constructed wetland

by Antonio Albuquerque

L. Amado, A. Albuquerque, A. Espirito Santo
Ecological Engineering, 2012, V. 39, 16-23.

This research work evaluates the impact of stormwater infiltration on the removal of organics, solids, nitrogen and... more This research work evaluates the impact of stormwater infiltration on the removal of organics, solids, nitrogen and phosphorus in a LECA-based horizontal subsurface flow constructed wetland. Stormwater runoff for the period between January 2008 and June 2010 (30 months) was estimated for the drainage basin of the Vila Fernando wastewater treatment plant (constructed wetland system) and it was observed proportionality between the increase in surface runoff and the infiltration flow rate that reached the plant. The average stormwater infiltration rate that reached the plant was 67.4 m(3) d(-1) (77% of the influent flow rate into the plant). The 30 month monitoring campaign set up at one of the reed beds showed that stormwater infiltration led to a high variation of the hydraulic loading rate (HLR) throughout the bed, which affected its performance in the removal of organic matter, suspended solids and nitrogen. For a HLR below 20 cm d-1 the removal efficiencies for BOD5, COD and TSS doubled. The removal of nitrogen was too low and was associated with the weak development of nitrifying biofilm and the poor growth of reeds. However, it was observed a good relationship between the applied and removed loads for most of the parameters, which seems to indicate that the organic, solid, nitrogen and phosphorus loading rates influenced the respective removal rates. The use of a bed material with high specific surface area, such as LECA, can only improve the treatment capacity of horizontal subsurface flow systems if the organic and solid loading rates, as well as the HLR, can be effectively controlled.

Morbidity in the Marshes: Using Spatial Epidemiology to Investigate Skeletal Evidence for Malaria in Anglo-Saxon England (AD410-1050).

by Gaynor Western

Gowland, R.L. & Western, A.G. 2012. American Journal of Physical Anthropology 147(2): 301-311.

Discriminating papyrus (Cyperus papyrus) and its co-existence species using random forest and hyperspectral data resampled to HYMAP

by Riyad Ismail

Adam, E, Mutanga, O, Rugege, D and Ismail, R, 2012

Techniques for discriminating swamp wetland species are critical for the rapid assessment and proactive management of... more Techniques for discriminating swamp wetland species are critical for the rapid assessment and proactive management of wetlands. In this study, we tested whether the random forest (RF) algorithm could discriminate between papyrus swamp and its co-existent species (Phragmites australis, Echinochloa pyramidalis and Thelypteris interrupta) using in situ canopy reflectance spectra. Canopy spectral measurements were taken from the species using analytical spectral devices but later resampled to Hyperspectral Mapper (HYMAP) resolution. The RF algorithm and a simple forward variable selection (FVS) technique were used to identify key wavelengths for discriminating papyrus swamp and its co-existence species. The method yielded 10 wavelengths located in the visible and short-wave infrared portions of the electromagnetic spectrum with a lowest out-of-bag (OOB) estimate error rate of 9.5% and .632+ bootstrap error of 8.95%. The use of RF as a classification algorithm resulted in overall accuracy of 90.50% and a kappa value of 0.87, with individual class accuracies ranging from 93.73% to 100%. Additionally, the results from this study indicate that the RF algorithm produces better classification results than conventional classification trees (CTs) when using all HYMAP wavelengths (n = 126) and when using wavelengths selected by the FVS technique.

Migratory benthic fishes may induce regime shifts in a tropical floodplain pond

by Roger Paulo Mormul

Freshwater Biology 2012 - accepted and awaiting online first version

Alternative states are a widely recorded phenomenon in shallow lakes, which may shift between turbid and clear water... more Alternative states are a widely recorded phenomenon in shallow lakes, which may shift between turbid and clear water conditions. Here we investigate whether such shifts in a tropical floodplain pond may be related to the effect of the flood pulse regime on the community structures of fish and macrophytes. Using a long-term data set, we demonstrate how benthic fish migration together with colonization by submerged plants affected the transition from a turbid to a macrophyte-dominated state in a floodplain pond without top-down control. In our study, the turbid state occurred mostly during low water phases (in contrast to the pattern in temperate regions) and was largely characterized by high values for the biomass of benthic fish, chlorophyll-a and total phosphorous. During the period of rising water levels, the migration of benthic fish out of the pond occurs simultaneously with the establishment of submerged plants, while water turbidity decreases along with phytoplankton and nutrient concentrations, inducing a clear-water phase. However, when submerged plants are absent and fish migration is low, a transient state is generated. We suggest that, different from the temperate ponds and shallow lakes, where the main driving mechanisms establishing alternative states are related to cascading effects via the food chain, in the tropical ponds and shallow lakes, resuspension of sediments by benthic fish may play the most significant role in establishing alternative states. However, the effect of the flood pulse regime plays an important role in the temporal dynamics of fish community structure by controlling benthic fish migration.

Preservation and degradation of the wood

by Marcus Brittain

2010 (pages 4-11)

In Pryor, F. and M. Bamforth (ed.), Excavations at Flag Fen, Peterborough: 1995-2007' Oxford: Oxbow

An assessment of the current and changing preservational condition of the burial context of late Bronze Age and early... more An assessment of the current and changing preservational condition of the burial context of late Bronze Age and early Iron Age waterlogged wood within the Flag Fen basin, Cambridgeshire, UK. These timbers form one of Europe's largest prehistoric timber constructions that has invariably been interpreted as a dwelling, a walkway, and a ritual centre.

Wetland Resource Use in Xe Pian National Protected Area, Lao PDR in 2005

by Chris Hallam

Pester_etal_2012_Frontiers

by Klaus-Holger Knorr

Freshwater wetlands are a major source of the greenhouse gas methane but at the same time can function as carbon sink.... more Freshwater wetlands are a major source of the greenhouse gas methane but at the same time can function as carbon sink. Their response to global warming and environmental pollution is one of the largest unknowns in the upcoming decades to centuries. In this review, we highlight the role of sulfate-reducing microorganisms (SRM) in the intertwined element cycles of wetlands. Although regarded primarily as methanogenic environments, biogeochemical studies have revealed a previously hidden sulfur cycle in wetlands that can sustain rapid renewal of the small standing pools of sulfate. Thus, dissimilatory sulfate reduction, which frequently occurs at rates comparable to marine surface sediments, can contribute up to 36–50% to anaerobic carbon mineralization in these ecosystems. Since sulfate reduction is thermodynamically favored relative to fermentative processes and methanogenesis, it effectively decreases gross methane production thereby mitigating the flux of methane to the atmosphere. However, very little is known about wetland SRM. Molecular analyses using dsrAB [encoding subunit A and B of the dissimilatory (bi)sulfite reductase] as marker genes demonstrated that members of novel phylogenetic lineages, which are unrelated to recognized SRM, dominate dsrAB richness and, if tested, are also abundant among the dsrAB-containing wetland microbiota. These discoveries point toward the existence of so far unknown SRM that are an important part of the autochthonous wetland microbiota. In addition to these numerically dominant microorganisms, a recent stable isotope probing study of SRM in a German peatland indicated that rare biosphere members might be highly active in situ and have a considerable stake in wetland sulfate reduction. The hidden sulfur cycle in wetlands and the fact that wetland SRM are not well represented by described SRM species explains their so far neglected role as important actors in carbon cycling and climate change.

Hydrodynamic and water quality processes in mangrove regions

by Roger Falconer - Cardiff University

Paper 61:  Struve, J. and Falconer, R. A. 2001. Hydrodynamic and water quality processes in mangrove regions. Journal of Coastal Research, Special Issue

Nutrient Removal from Atchafalaya during 2011 flood

by Y. Jun Xu

Macrophyte structural complexity influences spider assemblage attributes in wetlands

by Roger Paulo Mormul

Wetlands 2012

Macrophytes increase structural complexity in aquatic ecosystems and their emergent structures provide habitats for... more Macrophytes increase structural complexity in aquatic ecosystems and their emergent structures provide habitats for spiders. We sampled spiders in three species of macrophytes (Eichhornia azurea, Eichhornia crassipes and Limnobium laevigatum) and measured five traits indicative of structural complexity: horizontal structure, vertical structure, plant height, macrophyte richness and macrophyte biomass. We tested the hypothesis that spider density and diversity increase and guild composition changes along a gradient of structural complexity provided by macrophytes. Vertical and horizontal structure and macrophyte richness covaried with the attributes of spider assemblages. However, vertical structure was an important habitat-complexity trait because it covaried with all spider attributes investigated, positively affecting density and taxa richness and changing guild composition. Our findings suggest that the increase in macrophyte structural complexity, primarily through vertical structure, provides additional habitat and microhabitat variability. These forms of variability may increase the availability of prey and shelter and even reduce intraguild predation between spiders, thereby potentially increasing density and taxa richness. Moreover, an increase in vertical complexity provides available structures for web attachment, favoring web-building spiders and consequently affecting guild composition. Thus, habitat structure plays an important role in structuring spider assemblages and specific traits may mediate changes in particular attributes of spider assemblages.

Expansion rate and geometry of floating vegetation mats on the margins of thermokarst lakes, northern Seward Peninsula, Alaska, USA

by Andrew Parsekian

SUBSURFACE GEOLOGIC CONTROLS ON ISOLATED WETLANDS IN THE PINELANDS OF NEW JERSEY

by Andrew Parsekian