The influence of water-table depth and pH on the spatial distribution of diatom species in peatlands of the Boreal Shield and Hudson Plains, Canada

Botany ◽  
2015 ◽  
Vol 93 (2) ◽  
pp. 57-74 ◽  
Author(s):  
Kathryn E. Hargan ◽  
Kathleen M. Rühland ◽  
Andrew M. Paterson ◽  
Sarah A. Finkelstein ◽  
James R. Holmquist ◽  
...  
Keyword(s):  
Environmental Change ◽  
Water Table ◽  
Vegetation Type ◽  
Diatom Assemblage ◽  
Diatom Species ◽  
Diatom Assemblages ◽  
Poor Fen ◽  
Influence Of Water ◽  
Boreal Shield ◽  
Northern Peatlands

Diatoms collected from 113 surface peat samples from the Boreal Shield and Hudson Plains show taxonomic distributions that are associated with macro-vegetation type, pH, and position relative to the water table, the main environmental variables measured in this study. The overall goal of our research was to determine the ecological distribution and response of diatoms to microhabitat conditions, and to assess the potential for diatoms to be applied as indicators of long-term environmental change in northern peatlands. Our results indicate that diatom assemblage composition was determined by both the broader peatland type (i.e., bog, rich and poor fens) and microhabitats within peatland formations (e.g., hummock, hollow). The diatom assemblages were primarily influenced by pH with the sites divided at a critical pH of 5.5, and secondarily by the depth to the water table. Acidic bog hollow and hummock microhabitats were species-poor and dominated almost exclusively by Eunotia paludosa A.Grunow and (or) Eunotia mucophila (H.Lange-Bertalot, M.Nörpel-Schempp & E.Alles) H.Lange-Bertalot. These acidophilic and aerophilic diatom species were associated with the narrow pH optima of the dominant Sphagnum L. species (e.g., Sphagnum fuscum (Schimp.) Klinggr., Sphagnum angustifolium (C.E.O.Jensen ex Russow) C.E.O.Jensen) found in these bog habitats. Rich and poor fen samples, which were less acidic, supported a more diverse diatom assemblage (>30 species) with greater variability in both diatom and bryophyte pH tolerances. The diatom assemblages recorded in the bogs and fens of our study are similar to those found in peatlands around the world, demonstrating that diatom species are very specialized to exist in these often harsh semi-aquatic environments. Diatoms from peatlands have great potential as biomonitors of environmental change in these important ecosystems.

Patterned fens of western Labrador and adjacent Quebec: phytosociology, water chemistry, landform features, and dynamics of surface patterns

1988 ◽  
Vol 66 (12) ◽  
pp. 2402-2418 ◽  
Author(s):  
David R. Foster ◽  
George A. King ◽  
Mary V. Santelmann
Keyword(s):  
Water Chemistry ◽  
Water Table ◽  
Vegetation Type ◽  
Open Water ◽  
Differential Rate ◽  
Peat Accumulation ◽  
Surface Patterns ◽  
Vegetation Water ◽  
Northern Peatlands ◽  
Pool Formation

The landforms, vegetation, water chemistry, and stratigraphy of four patterned fens (aapamires) in western Labrador and adjacent Quebec are described in a study investigating the origin and characteristics of surface patterns on northern peatlands. Phytosociological analysis by the relevé approach, in conjunction with analysis by TWINSPAN, is used to describe 11 floristic noda. The vegetational patterns are largely controlled by depth to the water table. Mire landforms discussed in detail include ice-push ridges, flarks and pools, peat ridges, and mire-margin hummocks. Water chemistry is typical of minerotrophic conditions, with pH ranging from 4.4 to 6.7 and calcium concentrations from 20 to 430 μiequiv. L−1. The water chemistry, vegetation, and landforms on the mires are compared with other studies from Labrador and circumboreal regions. Stratigraphic results and field observations support the theory that surface patterns on the mire develop slowly through the interplay of biological and hydrological processes, specifically differential rate of peat accumulation controlled by vegetation type and depth to water table. Pool formation apparently involves four steps: (i) gradual differentiation of shallow flarks on previously undifferentiated mire surface; (ii) expansion and deepening of flarks and development of ridges due to differential peat accumulation; (iii) degradation of flark vegetation into mud bottoms and open-water pools; and (iv) coalescence, continued expansion, and deepening of open-water areas. Hydrological controls over the rate and extent of pool formation are discussed as a probable explanation of the geographical distribution of patterned mires.

scholarly journals Methane flux from drained northern peatlands: Effect of a persistent water table lowering on flux

1993 ◽  
Vol 7 (4) ◽  
pp. 749-769 ◽  
Author(s):  
Nigel T. Roulet ◽  
R. Ash ◽  
W. Quinton ◽  
Tim Moore
Keyword(s):  
Water Table ◽  
Methane Flux ◽  
Northern Peatlands

scholarly journals Influence of Water Table Fluctuation on Natural Source Zone Depletion in Hydrocarbon Contaminated Subsurface Environments

2020 ◽  
Author(s):  
Reem Ismail ◽  
Saeid Shafieiyoun ◽  
Riyadh Al Raoush ◽  
Fereidoun Rezanezhad
Keyword(s):  
Water Table ◽  
Contaminated Soil ◽  
Soil Surface ◽  
Source Zone ◽  
Water Table Fluctuation ◽  
Mass Removal ◽  
Water Table Fluctuations ◽  
Water Conditions ◽  
Static Water ◽  
Influence Of Water

Most of the prediction theories regarding dissolution of organic contaminants in the subsurface systems have been proposed based on the static water conditions; and the influence of water fluctuations on mass removal requires further investigations. In this study, it was intended to investigate the effects of water table fluctuations on biogeochemical properties of the contaminated soil at the smear zone between the vadose zone and the groundwater table. An automated 60 cm soil column system was developed and connected to a hydrostatic equilibrium reservoir to impose the water regime by using a multi-channel pump. Four homogenized hydrocarbon contaminated soil columns were constructed and two of them were fully saturated and remained under static water conditions while another two columns were operated under water table fluctuations between the soil surface and 40 cm below it. The experiments were run for 150 days and relevant geochemical indicators as well as dissolved phase concentrations were analyzed at 30 and 50 cm below the soil surface in all columns. The results indicated significant difference in terms of biodegradation effectiveness between the smear zones exposed to static and water table fluctuation conditions. This presentation will provide an overview of the experimental approach, mass removal efficiency, and key findings.

scholarly journals Using Terrestrial Laser Scanning to Characterize Peatland Microtopography and Assess Tree Growth Responses to Elevated Temperature and CO2

2020 ◽  
Author(s):  
Jake D. Graham
Keyword(s):  
Elevated Temperature ◽  
Environmental Change ◽  
Primary Production ◽  
Tree Growth ◽  
Land Surface ◽  
Net Primary Production ◽  
Growth Responses ◽  
Aboveground Net Primary Production ◽  
Response To Temperature ◽  
Northern Peatlands

Northern peatlands are a major terrestrial carbon (C) store, with an annual sink of 0.1 Pg C yr-1 and a total storage estimate of 547 Pg C. Northern peatlands are also major contributors of atmospheric methane, a potent greenhouse gas. The microtopography of peatlands helps modulate peatland carbon fluxes; however, there is a lack of quantitative characterizations of microtopography in the literature. The lack of formalized schemes to characterize microtopography makes comparisons between studies difficult. Further, many land surface models do not accurately simulate peatland C emissions, in part because they do not adequately represent peatland microtopography and hydrology. The C balance of peatlands is determined by differences in C influxes and effluxes, with the largest being net primary production and heterotrophic respiration, respectively. Tree net primary production at a treed bog in northern Minnesota represented about 13% of C inputs to the peatland, and marks tree aboveground net primary production (ANPP) as an important pathway for C to enter peatlands. Tree species Picea mariana (Black spruce) and Larix Laricina (Tamarack) are typically found in wooded peatlands in North America, and are widely distributed in the North American boreal zone. Therefore, understanding how these species will respond to environmental change is needed to make predictions of peatland C budgets in the future. As the climate warms, peatlands are expected to increase C release to the atmosphere, resulting in a positive feedback loop. Further, climate warming is expected to occur faster in northern latitudes compared to the rest of the globe. The Spruce and Peatland Responses Under Changing Environments (SPRUCE; https://mnspruce.ornl.gov/) manipulates temperature and CO2 concentrations to evaluate the in-situ response of a peatland to environmental change and is located in Minnesota, USA. In this dissertation, I documented surface roughness metrics for peatland microtopography in SPRUCE plots and developed three explicit methods for classifying frequently used microtopographic classes (microforms) for different scientific applications. Subsequently I used one of these characterizations to perform a sensitivity analysis and improve the parameterization of microtopography in a land surface model that was calibrated at the SPRUCE site. The modeled outputs of C from the analyses ranged from 0.8-34.8% when microtopographical parameters were allowed to vary within observed ranges. Further, C related outputs when using our data-driven parameterization differed from outputs when using the default parameterization by -7.9 - 12.2%. Finally, I utilized TLS point clouds to assess the effect elevated temperature and CO2 concentrations had on P. mariana and L. laricina after the first four years of SPRUCE treatments. I observed that P. mariana growth (aboveground net primary production) had a negative response to temperature initially, but the relationship became less pronounced through time. Conversely, L. laricina had no growth response to temperature initially, but developed a positive relationship through time. The divergent growth responses of P. mariana and L. laricina resulted in no detectable change in aboveground net primary production at the community level. Results from this dissertation help improve how peatland microtopography is represented, and improves understanding of how peatland tree growth will respond to environmental change in the future.

Monitoring of water table dynamics in peatlands with OPTRAM: Towards globally applicable algorithms in Google Earth Engine using Landsat and Sentinel-2

2021 ◽  
Author(s):  
Iuliia Burdun ◽  
Michel Bechtold ◽  
Viacheslav Komisarenko ◽  
Annalea Lohila ◽  
Elyn Humphreys ◽  
...  
Keyword(s):  
Time Series ◽  
Water Table ◽  
Input Data ◽  
Short Wave ◽  
Google Earth ◽  
Google Earth Engine ◽  
Short Wave Infrared ◽  
Northern Peatlands ◽  
Sentinel 2

<p>Fluctuations of water table depth (WTD) affect many processes in peatlands, such as vegetation development and emissions of greenhouse gases. Here, we present the OPtical TRApezoid Model (OPTRAM) as a new method for satellite-based monitoring of the temporal variation of WTD in peatlands. OPTRAM is based on the response of short-wave infrared reflectance to the vegetation water status. For five northern peatlands with long-term in-situ WTD records, and with diverse vegetation cover and hydrological regimes, we generate a suite of OPTRAM index time series using (a) different procedures to parametrise OPTRAM (peatland-specific manual vs. globally applicable automatic parametrisation in Google Earth Engine), and (b) different satellite input data (Landsat vs. Sentinel-2). The results based on the manual parametrisation of OPTRAM indicate a high correlation with in-situ WTD time-series for pixels with most suitable vegetation for OPTRAM application (mean Pearson correlation of 0.7 across sites), and we will present the performance differences when moving from a manual to an automatic procedure. Furthermore, for the overlap period of Landsat and Sentinel-2, which have different ranges and widths of short-wave infrared bands used for OPTRAM calculation, the impact of the satellite input data to OPTRAM will be analysed. Eventually, the challenge of merging different satellite missions in the derivation of OPTRAM time series will be explored as an important step towards a global application of OPTRAM for the monitoring of WTD dynamics in northern peatlands.</p>

Fossil diatom assemblages as paleoecological indicators of paleo-water environmental change in the Ulleung Basin, East Sea, Republic of Korea

2017 ◽  
Vol 52 (3) ◽  
pp. 345-357 ◽  
Author(s):  
Suk Min Yun ◽  
Taehee Lee ◽  
Seung Won Jung ◽  
Joon Sang Park ◽  
Jin Hwan Lee
Keyword(s):  
Environmental Change ◽  
East Sea ◽  
Ulleung Basin ◽  
Republic Of Korea ◽  
Diatom Assemblages

Effects of Didymosphenia geminata blooms on benthic diatom assemblages in the Restigouche River Watershed, eastern Canada

Botany ◽  
2015 ◽  
Vol 93 (5) ◽  
pp. 317-323 ◽  
Author(s):  
Branaavan Sivarajah ◽  
Joshua Kurek ◽  
Kathleen M. Rühland ◽  
John P. Smol
Keyword(s):  
Benthic Diatom ◽  
Diatom Assemblage ◽  
Diatom Assemblages ◽  
Eastern Canada ◽  
Didymosphenia Geminata ◽  
Assemblage Composition ◽  
River Watershed ◽  
And Function ◽  
Riverine Systems ◽  
The Impact

Nuisance Didymosphenia geminata (Lyngbye) M. Schmidt (didymo) blooms were first reported in 2006 from the Restigouche River Watershed (RRW), eastern Canada. Although government agencies and recreational users are concerned about these blooms, little is known about the impact on biota and (or) the structure and function of the relatively pristine riverine systems of the RRW. Here, we assess whether didymo blooms affect overall benthic diatom assemblage composition by examining epilithic samples from middle stretches of the Patapedia and Upsalquitch rivers. Significant (albeit minor) differences (P < 0.05) in diatom assemblage composition between sites, with and without didymo blooms, were only observed from the Patapedia River. Rarefied diatom species diversity (Hill’s N2) and rarefied richness did not differ significantly among sites, regardless of the presence or absence of blooms. Our data show that didymo blooms have minimal effect on benthic diatom assemblage composition in the RRW.

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