scholarly journals The disintegration of populations of underwater plants in soft water lakes enriched with acidic organic matter

2011 ◽  
Vol 73 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Józef Szmeja ◽  
Katarzyna Bociąg
Keyword(s):  
Organic Matter ◽  
Environmental Changes ◽  
Submerged Macrophytes ◽  
General Pattern ◽  
Water Concentration ◽  
Soft Water ◽  
Peat Bogs ◽  
Humic Lakes ◽  
Fontinalis Antipyretica ◽  
Doc Concentration

The characteristics of habitats, individuals and populations of four submerged macrophytes, <em>Lobelia dortmanna </em>L., <em>Isoetes lacustris </em>L., <em>Sphagnum denticulatum </em>Brid. and <em>Fontinalis antipyretica </em>Hedw., were studied in 12 soft water oligohumic lakes which had no inflow of allochtonic DOM and the DOC concentration in the water was &lt;4.0 mg C dm<sup>-3</sup> and 13 humic lakes enriched with allochthonous dissolved organic matter (DOM) from drained peat bogs and ranging in DOC water concentration from 4.1 to 44.0 mg C dm<sup>-3</sup>. The analyses of population disintegration were conducted basing on characteristics of individuals (size, habitat, fertility) and populations (aggregation density index, settlement index of the population area). The settlement index of the population area for <em>Lobelia</em>, <em>Fontinalis</em>, <em>Isoetes</em>, <em>Sphagnum</em> decreased from 8.4 to 6.2 g d.w. m<sup>-2</sup>, 4.6 to 0.01 g d.w. m<sup>-2</sup>, 85.4 to &lt;0.001 g d.w. m<sup>-2</sup> and 39.3 to 7.2 g d.w. m<sup>-2</sup>, respectively. Similar trends were observed in aggregation density. The general pattern of the disintegration of populations of these species was always similar. It was independent of the source macrophytes drew resources from or their susceptibility to environmental changes. Individuals began to be eliminated from the deep and central parts of the population area. The remainder of the populations, which persist in the shallowest, best-illuminated part of the area, are themselves endangered by disturbances caused by wavy motion. The only populations of submerged macrophytes which can survive in polyhumic lakes under such conditions are those which are resistant to disturbances common in the shallow littoral (<em>Lobelia dortmanna</em>, <em>Fontinalis antipyretica</em>).

Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years

2008 ◽  
Vol 42 (1) ◽  
pp. 81-102 ◽  
Author(s):  
Christoph Mayr ◽  
Andreas Lücke ◽  
Nora I. Maidana ◽  
Michael Wille ◽  
Torsten Haberzettl ◽  
...  
Keyword(s):  
Organic Matter ◽  
Environmental Changes ◽  
Southern Patagonia

Distribution pattern of epiphytic microcrustaceans in relation to different macrophyte microhabitats in a shallow wetland (Upo wetlands, South Korea)

2015 ◽  
Vol 44 (2) ◽  
Author(s):  
Jong-Yun Choi ◽  
Seong-Ki Kim ◽  
Kwang-Seuk Jeong ◽  
Gea-Jae Joo
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Submerged Macrophytes ◽  
Submerged Macrophyte ◽  
Ceratophyllum Demersum ◽  
Suitable Habitat ◽  
Seasonal Growth ◽  
Spirodela Polyrhiza ◽  
Macrophyte Species ◽  
Salvinia Natans

AbstractMacrophytes determine the physical complexity of aquatic environments and provide a suitable habitat for colonization by microcrustaceans. We evaluated the effects of a seasonal growth pattern and structure of macrophyte species on epiphytic microcrustaceans collected from macrophyte surfaces (stems and leaves) in shallow wetlands from May 2011 to October 2012. In 2011, epiphytic microcrustaceans that preferred free-floating macrophytes (Spirodela polyrhiza and Salvinia natans) and submerged macrophytes (Potamogeton crispus and Ceratophyllum demersum) were affected by the seasonal growth of these species. Epiphytic microcrustaceans were abundant on the surface of Spirodela polyrhiza in June and August and on Salvinia natans in September and October. In 2012, epiphytic microcrustaceans preferred submerged macrophyte species over the free-floating ones. The results of stable isotope analysis showed that epiphytic microcrustaceans depend on epiphytic particulate organic matter (EPOM) from each macrophyte species rather than on suspended particulate organic matter. Small species (Coronatella rectangula, Pleuroxus laevis, and Chydorus sphaericus) used EPOM (dominated by epiphytic algae) on free-floating and submerged macrophyte species; however, relatively larger species (Ilyocryptus spinifer and Macrothrix rosea) used EPOM only from submerged macrophytes. Based on these findings, we conclude that the distribution of epiphytic microcrustaceans is determined by seasonal characteristics, morphology of macrophyte species, and abundance of food resources.

scholarly journals A global hotspot for dissolved organic carbon in hypermaritime watersheds of coastal British Columbia

2017 ◽  
Vol 14 (15) ◽  
pp. 3743-3762 ◽  
Author(s):  
Allison A. Oliver ◽  
Suzanne E. Tank ◽  
Ian Giesbrecht ◽  
Maartje C. Korver ◽  
William C. Floyd ◽  
...  
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Organic Carbon ◽  
Stream Water ◽  
Coastal Ocean ◽  
Stream Discharge ◽  
Coastal Margin ◽  
Doc Concentration ◽  
Small Catchments ◽  
Dom Composition

Abstract. The perhumid region of the coastal temperate rainforest (CTR) of Pacific North America is one of the wettest places on Earth and contains numerous small catchments that discharge freshwater and high concentrations of dissolved organic carbon (DOC) directly to the coastal ocean. However, empirical data on the flux and composition of DOC exported from these watersheds are scarce. We established monitoring stations at the outlets of seven catchments on Calvert and Hecate islands, British Columbia, which represent the rain-dominated hypermaritime region of the perhumid CTR. Over several years, we measured stream discharge, stream water DOC concentration, and stream water dissolved organic-matter (DOM) composition. Discharge and DOC concentrations were used to calculate DOC fluxes and yields, and DOM composition was characterized using absorbance and fluorescence spectroscopy with parallel factor analysis (PARAFAC). The areal estimate of annual DOC yield in water year 2015 was 33.3 Mg C km−2 yr−1, with individual watersheds ranging from an average of 24.1 to 37.7 Mg C km−2 yr−1. This represents some of the highest DOC yields to be measured at the coastal margin. We observed seasonality in the quantity and composition of exports, with the majority of DOC export occurring during the extended wet period (September–April). Stream flow from catchments reacted quickly to rain inputs, resulting in rapid export of relatively fresh, highly terrestrial-like DOM. DOC concentration and measures of DOM composition were related to stream discharge and stream temperature and correlated with watershed attributes, including the extent of lakes and wetlands, and the thickness of organic and mineral soil horizons. Our discovery of high DOC yields from these small catchments in the CTR is especially compelling as they deliver relatively fresh, highly terrestrial organic matter directly to the coastal ocean. Hypermaritime landscapes are common on the British Columbia coast, suggesting that this coastal margin may play an important role in the regional processing of carbon and in linking terrestrial carbon to marine ecosystems.

scholarly journals Assessing the Contribution of Seasonality, Tides, and Microbial Processing to Dissolved Organic Matter Composition Variability in a Southeastern U.S. Estuary

2021 ◽  
Vol 8 ◽  
Author(s):  
Rachel P. Martineac ◽  
Alexey V. Vorobev ◽  
Mary Ann Moran ◽  
Patricia M. Medeiros
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Critical Role ◽  
Bacterial Cells ◽  
Secondary Importance ◽  
Relative Contribution ◽  
Doc Concentration ◽  
Compositional Changes ◽  
Dom Composition

Uncovering which biogeochemical processes have a critical role controlling dissolved organic matter (DOM) compositional changes in complex estuarine environments remains a challenge. In this context, the aim of this study is to characterize the dominant patterns of variability modifying the DOM composition in an estuary off the Southeastern U.S. We collected water samples during three seasons (July and October 2014 and April 2015) at both high and low tides and conducted short- (1 day) and long-term (60 days) dark incubations. Samples were analyzed for bulk DOC concentration, and optical (CDOM) and molecular (FT-ICR MS) compositions and bacterial cells were collected for metatranscriptomics. Results show that the dominant pattern of variability in DOM composition occurs at seasonal scales, likely associated with the seasonality of river discharge. After seasonal variations, long-term biodegradation was found to be comparatively more important in the fall, while tidal variability was the second most important factor correlated to DOM composition in spring, when the freshwater content in the estuary was high. Over shorter time scales, however, the influence of microbial processing was small. Microbial data revealed a similar pattern, with variability in gene expression occurring primarily at the seasonal scale and tidal influence being of secondary importance. Our analyses suggest that future changes in the seasonal delivery of freshwater to this system have the potential to significantly impact DOM composition. Changes in residence time may also be important, helping control the relative contribution of tides and long-term biodegradation to DOM compositional changes in the estuary.

scholarly journals Particulate organic matter composition and organic carbon flux in Arctic valley glaciers: examples from the Bayelva River and adjacent Kongsfjorden

2015 ◽  
Vol 12 (18) ◽  
pp. 15655-15685
Author(s):  
Z.-Y. Zhu ◽  
Y. Wu ◽  
S.-M. Liu ◽  
F. Wenger ◽  
J. Hu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Particulate Organic Matter ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Concentration Data ◽  
Particulate Nitrogen ◽  
Organic Carbon Flux ◽  
Doc Concentration ◽  
The Face

Abstract. In the face of ongoing global warming and glacier retreat, the composition and flux of organic matter in glacier–fjord systems are key variables for updating the carbon cycle and budget, whereas the role of Arctic valley glaciers seems unimportant when compared with the huge Greenland Ice Sheet. Our field observations of the glacier-fed Bayelva River, Svalbard, and the adjacent Kongsfjorden allowed us to determine the compositions of particulate organic matter from glacier to fjord and also to estimate the flux of organic carbon, both for the river and for Svalbard in general. Particulate organic carbon (POC) and dissolved organic carbon (DOC) in the Bayelva River averaged 56 and 73 μM, respectively, in August 2012. Amino acids (AAs) and phytoplankton pigments accounted for ~ 10 % of the particulate organic matter (POM) in the Bayelva River, while AAs represented > 90 % of particulate nitrogen in fjord surface water, suggesting the strong in situ assimilation of organic matter. Bacteria accounts for 13 and 19 % of the POC in the Bayelva River and the Kongsfjorden, respectively, while values for particulate nitrogen (PN) are much higher (i.e., 36 % in Kongsfjorden). The total discharge from the Bayelva River in 2012 was 29 × 106 m3. Furthermore, we calculated the annual POC, DOC, and PN fluxes for the river as 20 ± 1.6, 25 ± 5.6, and 4.7 ± 0.75 t, respectively. Using the POC content and DOC concentration data, we then estimated the annual POC and DOC fluxes for Svalbard glaciers. Although the estimated POC (0.056 ± 0.02 × 106 t yr−1) and DOC (0.02 ± 0.01 × 106 t yr−1) fluxes of Svalbard glaciers are small compared with those of the Greenland Ice Sheet, the area-weighted POC flux of Svalbard glaciers is twice that of the Greenland Ice Sheet, while the flux of DOC can be 4 to 7 times higher. Therefore, we propose that valley glaciers are efficient high-latitude sources of organic carbon.

Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy

2015 ◽  
Vol 95 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Kristine M. Haynes ◽  
Michael D. Preston ◽  
James W. McLaughlin ◽  
Kara Webster ◽  
Nathan Basiliko
Keyword(s):  
Organic Matter ◽  
Microbial Communities ◽  
Environmental Changes ◽  
Functional Redundancy ◽  
Organic Substrates ◽  
Metabolic Potential ◽  
Vegetation Communities ◽  
Chemical Complexity ◽  
Poor Fen

Haynes, K. M., Preston, M. D., McLaughlin, J. W., Webster, K. and Basiliko, N. 2015. Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy. Can. J. Soil Sci. 95: 219–230. Climatic and environmental changes can lead to shifts in the dominant vegetation communities present in northern peatland ecosystems, including from Sphagnum- to vascular-dominated systems. Such shifts in vegetation result in changes to the chemical quality of carbon substrates for soil microbial decomposers, with leaves and roots deposited in the peat surface and subsurface that potentially decompose faster. This study characterized the bacterial and fungal communities present along a nutrient gradient ranging from rich to poor fen peatlands and assessed the metabolic potential of these communities to mineralize a variety of organic matter substrates of varying chemical complexity using substrate-induced respiration (SIR) assays. Distinct microbial communities existed between rich, intermediate and poor fens, but SIR in each of the three sites exhibited the same pattern of carbon mineralization, providing support for the concept of functional redundancy, at least under standardized in vitro conditions. Preferential mineralization of simple organic substrates in the rich fen and complex compounds in the poor fen was not observed. Similarly, no preference was given to “native” organic matter extracts derived from each fen, with microbial communities opting for the most bioavailable substrate. This study suggests that soil bacteria and fungi might be able to respond relatively rapidly to shifts in vegetation communities and subsequent changes in the quality of carbon substrate additions to peatlands associated with environmental and climatic change.

scholarly journals Seabed Resuspension in the Chesapeake Bay: Implications for Biogeochemical Cycling and Hypoxia

2020 ◽  
Vol 44 (1) ◽  
pp. 103-122
Author(s):  
Julia M. Moriarty ◽  
Marjorie A. M. Friedrichs ◽  
Courtney K. Harris
Keyword(s):  
Organic Matter ◽  
Chesapeake Bay ◽  
Water Column ◽  
Primary Productivity ◽  
Environmental Changes ◽  
Light Attenuation ◽  
Sediment Resuspension ◽  
Nitrogen Dynamics ◽  
Biogeochemical Model ◽  
Order Of Magnitude

AbstractSediment processes, including resuspension and transport, affect water quality in estuaries by altering light attenuation, primary productivity, and organic matter remineralization, which then influence oxygen and nitrogen dynamics. The relative importance of these processes on oxygen and nitrogen dynamics varies in space and time due to multiple factors and is difficult to measure, however, motivating a modeling approach to quantify how sediment resuspension and transport affect estuarine biogeochemistry. Results from a coupled hydrodynamic–sediment transport–biogeochemical model of the Chesapeake Bay for the summers of 2002 and 2003 showed that resuspension increased light attenuation, especially in the northernmost portion of the Bay, shifting primary production downstream. Resuspension also increased remineralization in the central Bay, which experienced larger organic matter concentrations due to the downstream shift in primary productivity and estuarine circulation. As a result, oxygen decreased and ammonium increased throughout the Bay in the bottom portion of the water column, due to reduced photosynthesis in the northernmost portion of the Bay and increased remineralization in the central Bay. Averaged over the channel, resuspension decreased oxygen by ~ 25% and increased ammonium by ~ 50% for the bottom water column. Changes due to resuspension were of the same order of magnitude as, and generally exceeded, short-term variations within individual summers, as well as interannual variability between 2002 and 2003, which were wet and dry years, respectively. Our results quantify the degree to which sediment resuspension and transport affect biogeochemistry, and provide insight into how coastal systems may respond to management efforts and environmental changes.

scholarly journals Land Use Changes Affecting Soil Organic Matter Accumulation in Topsoil and Subsoil in Northeast Thailand

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Benjapon Kunlanit ◽  
Laksanara Khwanchum ◽  
Patma Vityakon
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Agricultural Land ◽  
Soil Depth ◽  
General Pattern ◽  
Clay Fraction ◽  
High Rate ◽  
Soil Profiles ◽  
Land Uses

The objectives of this study were to investigate effects of land use on accumulation of soil organic matter (SOM) in the soil profile (0–100 cm) and to determine pattern of SOM stock distribution in soil profiles. Soil samples were collected from five soil depths at 20 cm intervals from 0 to 100 cm under four adjacent land uses including forest, cassava, sugarcane, and paddy lands located in six districts of Maha Sarakham province in the Northeast of Thailand. When considering SOM stock among different land uses in all locations, forest soils had significantly higher total SOM stocks in 0–100 cm (193 Mg·C·ha−1) than those in cassava, sugarcane, and paddy soils in all locations. Leaf litter and remaining rice stover on soil surfaces resulted in a higher amount of SOM stocks in topsoil (0–20 cm) than subsoil (20–100 cm) in some forest and paddy land uses. General pattern of SOM stock distribution in soil profiles was such that the SOM stock declined with soil depth. Although SOM stocks decreased with depth, the subsoil stock contributes to longer term storage of C than topsoils as they are more stabilized through adsorption onto clay fraction in finer textured subsoil than those of the topsoils. Agricultural practices, notably applications of organic materials, such as cattle manure, could increase subsoil SOM stock as found in some agricultural land uses (cassava and sugarcane) in some location in our study. Upland agricultural land uses, notably cassava, caused high rate of soil degradation. To restore soil fertility of these agricultural lands, appropriate agronomic practices including application of organic soil amendments, return of crop residues, and reduction of soil disturbance to increase and maintain SOM stock, should be practiced.

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