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The effect of lake water characteristics on decomposition of aquatic macrophytes

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In situ decomposition of the horn wort (Ceratophyllum demersum L.), the buckbean (Menyanthes trifoliata L.) and leaf blades of the yellow water lily (Nuphar lutea L.) was studied with the litter bag method in three small mid-forest lakes of different pH and nutrient content. Time course of decomposition and of nutrient release from decomposing plant material was best fitted with a logarithm approximation and not by usually used exponential fit. pH of lake waters strongly affected decomposition rates of C. demersum and M. trifoliata. No effect of nutrient concentrations in lake water or in plant tissues on decomposition was noted for any of the analysed plants. Organic carbon deficit is speculated as a possible reason for the observed pH effect on decomposition rates. Modification of particulate and soluble N:P ratios are underlined as a consequence of different N and P release from decomposing plant material.
... En octobre 2020 l'augmentation de la hauteur d'eau a provoqué la mort des cératophylles dans B1 qui se sont déposés sur les sédiments et ont été dégradés ce qui a entrainé la libération de NH4 + (Figure 7-13). Cette libération s'est prolongée sur plusieurs mois car le temps pour libérer 50 % de l'azote que contient C. demersum peut être long (Kufel et al., 2004). De plus, la diminution de la température ralentit la dégradation des cératophylles (Battle et Mihuc, 2000). ...
... La sénescence des autres végétaux en automne ne semble pas augmenter la quantité de PO4 3dans la colonne d'eau sauf lors de la disparition massive et rapide des C. submersum en octobre 2020 dans B1(Figure 7-17) ; il est possible qu'une grande partie reste accrétée aux sédiments(Knight et al., 2000). La libération de PO4 3est plus rapide et plus brève que celle de l'azote lors de la dégradation de végétaux aquatiques(Kufel et al., 2004 ;Paalme et al., 2002).Le pourcentage de phosphore prélevé par les végétaux aquatiques pour l'année 2020 peut être estimé comme pour l'azote. Il serait de 11±4 % pour B1, de 13±4 % pour B2 et de 21±4 % pour B3. ...
Thesis
Malgré la réglementation, la pollution anthropique (azote, phosphore, éléments-traces métalliques (ETM), produits pharmaceutiques, coliformes fécaux, etc.) liée aux rejets urbains (stations de traitement des eaux urbaines (STEU) et rejets urbains par temps de pluie (RUTP)) n'est pas négligeable car elle fragilise les écosystèmes aquatiques et peut nuire à la santé humaine. Pour améliorer cette situation, la quantité de polluants se trouvant dans les eaux usées traitées ou de ruissellement urbain doit être amoindrie. Les zones humides sont des merveilles de la nature et sont souvent qualifiées de rein de la Terre du fait de leurs facultés à filtrer les polluants ; elles seraient donc de bonnes candidates pour épurer ces eaux urbaines. Malheureusement, elles sont en fort déclin depuis quelques siècles (13 % des zones humides du 17ème siècle persistaient au début du 21ème siècle). C'est pourquoi en 2011 est né le projet AZHUREV (Aménagement d'une Zone Humide à Reims pour l'Épuration et le Vivant). Ce projet a permis la construction d'une zone humide artificielle (ZHA) ou zone de rejet végétalisée (ZRV) de grande taille (6 ha) (mise en eau en 2017) à la sortie de la STEU du Grand Reims (capacité de 470000 équivalents habitants). Elle est composée de trois bassins de 2 ha alimentés en parallèle, par une partie des effluents de la STEU (10 %), ou des RUTP (25 %) lors d'événements pluvieux, pour améliorer la qualité de ces eaux avant leur rejet dans l'environnement. Initialement ce qui différenciait ces bassins étaient la quantité et le type de végétaux émergés plantés (Phragmites australis, Glyceria maxima, Scirpus lacustris). Dorénavant ce n'est plus le cas car la proportion de végétaux plantés a drastiquement diminué, P. australis étant la seule espèce toujours présente, au profit d'espèces opportunistes (submergées ou flottantes). Ces bassins ont la capacité de réduire la concentration de nombreux composés via différents processus tels que l'oxydation/réduction (azote, ETM), la précipitation/coprécipitation avec les carbonates et le sulfure d'hydrogène (ETM), la biodégradation (produits pharmaceutiques), la photolyse (produits pharmaceutiques, coliformes fécaux) l'adsorption sur les sédiments (ETM et produits pharmaceutiques) ou encore l'assimilation des végétaux (azote et phosphore). La plupart de ces mécanismes sont dépendants à la fois des bactéries et des végétaux aquatiques. De ce fait la capacité d'épuration des bassins est supérieure en été grâce aux températures élevées et aux jours plus longs. L'activité bactérienne a un effet direct sur les polluants et les genres bactériens retrouvés à la sortie de la ZRV font partie du cycle de l'azote, du soufre et du carbone. L'effet des végétaux est quant à lui indirect en promouvant le développement bactérien (source de carbone et d'énergie, support pour le biofilm) et en apportant de la matière organique dans les sédiments lors de la sénescence (site d'adsorption pour les polluants). Ces végétaux sont aussi une source de nourriture, une zone d'habitat et/ou de nidification pour de nombreux animaux sauvages qu'ils soient considérés comme « nuisibles » (rat musqué ou ragondin) ou non (cygne, foulque, canard, grèbe, grenouille, libellule, demoiselle, gammare, limnée, etc.). L'intérêt environnemental de cette ZRV est double, car elle améliore la qualité des eaux urbaines avant leur rejet dans le milieu récepteur tout en fournissant le gîte et le couvert pour de nombreuses espèces animales dépendantes de ce type de milieu. L'interconnexion des multiples variables mesurées a été retranscrite sous la forme d'un modèle conceptuel. Ces résultats sont encourageants pour une éventuelle extension de la ZRV.
... Lignin is believed to be the main source of the soil organic matter, especially condensed aromatic molecules (DiDonato et al. 2016). Herbaceous plants contain more lignin than mosses (Aleksandrova 1980;Orlov 1995;Beznosikov 2017, 2019) and decompose much faster than mosses (Kufel et al. 2004;Golovatskaya and Nikonova 2013). In our study, an intensive decomposition of Eriophorum sp. may be the reason for the lignin destruction followed by the formation of high molecular weight PAH structures. ...
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Aim To investigate PAH accumulation in the peat of the swampy hollows in the series of European Arctic tundra sites and to evaluate the effect of PAH composition in the living plants on the peat PAHs in view of their deposition depth and geographic location. Methods The samples were analyzed by the reversed phase HPLC in a gradient mode and spectrofluorimetrical detection. The ASE-350 Accelerated Solvent Extractor system was used for complete extraction of PAHs from peat and plants. Results We determined PAH content in mire plants and peat from three biomes of the European part of the Russian Arctic: forest-tundra, southern tundra, and northern tundra. A correlation analysis allowed us to reveal similarity in the PAH accumulation in plants of the different biomes. A PCA analysis highlighted differences between PAH profiles in different biomes studied. We found significant correlations between the degree of peat decomposition, the share of herbaceous plant residuals in the peat layers, the share of lignin in peat, and the content of 5,6-ring PAHs in peat. The patterns of PAH distribution across the peat layers may be used as a natural model for studying PAH transformation and formation of new PAHs from high molecular weight precursors of plant origin like lignin. There is a correlation between PAHs in the plant peat-formers on the surface and in the peat. Additional PAHs are formed as lignin and other complex organics and are decomposed in the course of peat formation that is associated mostly with herbaceous plant residuals destruction. Conclusion A total PAH accumulation in the peat is revealed to be decreasing and the PAH accumulation peaks—to be smoothed at the boundaries of the seasonally thawing layer and in the permafrost along the latitudinal gradient from south to north. In lower paleological peat horizons, it is explained by a botanical composition and historical period of peat-forming and in the upper peat layers, by a colder climate in the northern areas and changes in the fungal communities that decompose peat organic matter. The PAH composition is similar in terms of the dominant plant species at the peatlands of forest-tundra and northern tundra. We consider the data obtained on the PAH content in the plants to be applicable for other natural peatlands of the tundra and forest-tundra biomes.
... Their content per 1 g of the sample increases. For example, an experiment on the decomposition of herbs Ceratophyllum demersum L. and Menyanthes trifoliata L. and leaves of Nuphar lutea L. in lakes demonstrated that these species lose up to a half of the dry weight in acid medium (pH 4.4-5.2) over a 100-day period [23]. ...
Article
The composition of polycyclic aromatic hydrocarbons (PAHs) in vegetation of natural hummocky peatlands in the forest-tundra subzone of the Komi Republic and its possible impact on the composition of polyarenes in peat were assessed. The content of polyarenes was estimated by the method of highly efficient liquid chromatography. The accumulation of polycyclic aromatic hydrocarbons was the highest in Polytrichum strictum, Betula pubescens, and shoots of Picea abies and smaller in Betula nana L., Salix lapponum L., and Carex limosa L. with the domination of low-molecular-weight PAHs. We did not reveal dibenz[a,h]anthracene and benzo[ghi]perylene in plants: they could be the products of soil-forming processes. It is shown that distribution patterns of PAHs in the permafrost-affected soils of peat mounds (Hemic Folic Cryic Histosols) and in the soils of open-water mire pools (Fibric Floatic Histosols) are similar. Small quantities of low-molecular-weight polyarenes were normally accumulated in the seasonally thawed layer. The content of heavy structures (mainly, benzo[ghi]perylene) strongly increased at the contact with permafrost and then slightly decreased in the underlying permafrost. The composition of PAHs in the active layer mainly depended on composition of polyarenes in plants. At the contact with permafrost, the active synthesis or release of high-molecular-weight compounds took place. The influence of the composition of PAHs in plants on their composition in peat greatly depended on the degree of peat decomposition. Reasoning from the natural model of peat formation in open-water mire pools, the composition of polyarenes in the upper peat horizons of such sites was affected by recombination of low-molecular-weight hydrocarbons in Sphagnum riparium and Eriophorum sp. In the course of long-term soil development, the decomposition of complex organic compounds in plant tissues (particularly, in Eriophorum sp.) results in the formation of heavy PAHs with a simultaneous increase in the content of low-molecular-weight polyarenes.
... Rather, submerged macrophytes are often used as indicators of ecological status (Coops et al., 2007;Penning et al., 2008;Søndergaard et al., 2010). Polihumic lakes are generally depauperate of aquatic vegetation (Kufel et al., 2004). Indexes to qualify the ecological states are unavailable for these types of lakes. ...
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Aquatic vegetation greatly impacts lake functions. Forest ecosystems surrounding lakes are effective protection zone of lakes and their associated flora and fauna. The presence of aquatic plants depends on many factors, including the chemical composition and acidity of water, the shape of the lake catchment, the angle of slope along shorelines and the management of surrounding lands. Natural ecosystems throughout Eastern Europe are threatened by anthropogenic activities. Aquatic systems and bogs are particularly sensitive to disturbances. The aim of the study was to determine the influence of land management, forest type and stand age on aquatic plant colonisation within lakes as well as to quantify and qualify the structure of macrophyte communities within two lakes, Płotycze Sobiborskie and Orchowe, located in the Sobibór Landscape Park in western Poland. Even though there were few bogs within the catchment areas and lake buffer zones, where they did occur they had the greatest effect on macrophyte presence. The results of this research indicate that in the absence of anthropogenic disturbances midforest water-bog complexes are relatively stable systems and preserve their natural character. The applied multi-criteria evaluation of macrophytes in the studied lakes and their surrounding buffer zones and catchment areas allowed the lakes to be characterised as lakes with a good ecological status.
... (Pieczyńska 1972, Pieczyńska i in. 1984) oraz głębiej, w strefie pelagialu jeziornego (Kajak i in. 1975). W innych badaniach analizowano rolę, jaką pełnią różne grupy organizmów w obiegu materii organicznej jezior -w tym bakterie (Chróst 1983, 1984, Chróst i in. 1986, Siuda i Chróst 2002, fitoplankton (Chróst i in. 1981), wodne rośliny naczyniowe (Kufel i in. 2004), małże (Stańczykowska i in. 1976) oraz inne grupy bezkręgowców (Pieczyńska i in. 1993(Pieczyńska i in. , 1998. Do nielicznych należą badania zależności między zróżnicowaniem dekompozycji materii organicznej a statusem troficznym jezior (Godlewska-Lipowa 1974a, 1974b. ...
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SUMMARY1 Decomposition of the leaves of Nymphaea alba L. and Betula pubescens Ehrh. was studied in two ponds of contrasting pH, buffering capacity and trophic level. Rates of carbon loss, concentrations of nitrogen, protein and phenolics and colonization of the leaf material by macroinvertebrates were studied.2 Decomposition of B. pubescens leaves was slower than that of N. alba in both ponds. Protein and phenolic concentrations were higher in the decomposing N. alba material, whereas no significant difference was found for nitrogen concentrations.3 Decomposition of both species was slower in the acid water. The effect of acid water on decomposition rate was similar for both species. Both nitrogen and protein concentrations of N. alba remained higher under acid conditions, whereas no effect of study site was observed on the protein and nitrogen concentrations in B. pubescens litter. The concentration of phenolic compounds was higher in N. alba litter from the acid pond; no such difference was observed for B. pubescens litter. The high concentrations of phenolic compounds in N. alba litter from the acid pond probably induced chemical immobilization (tanning reaction), yielding high concentrations of nitrogen and protein in the litter.4 Diversity of the detritivorous macroinvertebrate fauna on the litter of both species was extremely low in the acid pond, while a relatively high diversity occurred in the alkaline water. Exclusion of large macrofauna inhibited decomposition in the alkaline water, while there was no comparable influence in the acid water.5 The effects of low pH on the decomposition of both terrestrial and aquatic macrophyte litter appeared to be caused by interactive effects of low pH on the microbial decomposition, on the detritivorous macroinvertebrates and, in the case of N. alba, on the resource quality of the detritus.
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The litter bag technique was used to study leaf decomposition in the large forested eutrophic (160.9 μmol l–1 DIN, 1.7 μmol l–1 SRP) Ebro river and in the forested Sènia (12.8 μmol l–1 DIN, 0.7 μmol l–1 RSP). Air dried leaves (3g) of Phragmites australis were used in both watercourses while Populus alba leaves were studied in the Ebro river only, and Populus nigra leaves and a submerged rooted macrophyte (stems and leaves), Potamogeton coloratus, were studied only in the Sènia stream. Litter bags of 100 μm and 1 mm mesh size were collected on days 0, 3, 15, 30, 90 and 120 and 5 mm mesh bags were sampled once after 30 days. Macroinvertebrates inside the leaf bags were retrieved and ash free dry weight and carbon and nitrogen contents of the remaining detritus were determined. Litter decomposition rates, k, were estimated using a simple exponential model. No significant differences in decomposition rates were observed between 100 μm and 1 mm mesh bags. In 100 μm litter bags, decomposition of P. nigra leaves from the Sènia stream (0.0104 day–1) was faster than that of P. alba leaves from the Ebro river (0.0049 day–1) (ANCOVA, p < 10–5). The decomposition rate of P. australis was higher in the Ebro river (0.009 ± 0.002 day–1) than in the Sènia stream (0.0056 ± 0.0004 day–1) for the first 30 days of decomposition, but no differences were observed from day 30 onwards. The number of macroinvertebrates increased over time and were mainly collectors-gatherers of the genus Chironomus. Percentage of detritus nitrogen increased in litter that had initially high C/N ratios (28.7 in P. alba and 64.7 in P. nigra) and decreased when initial C/N ratios were low (12.6 and 14.6 for P. australis from the Sènia and Ebro river respectively).
Article
The importance of detritus varies greatly among shore zones of lakes, but in a large majority of these regions detrital pathways prevail. Aside from a great spatial and seasonal variability, macrophytes and bottom sediments appear to be dominant stores of nutrients in these habitats. Macrophytes hold a central position in nutrient cycling in the shore-littoral lake zones. They are the main source of autochthonous detritus as they prevail in the total biomass of littoral organisms, and they are only rarely available as direct food of consumers. Various processes and interactions determine the role of macrophytes in nutrients dynamics. These are: the intensity of nutrient uptake and translocation, release of nutrients by healthy plants and from decomposing plants, exchange of elements between macrophytes and their periphyton, as well as interception of seston by macrophyte stands. Particular plant species differ in their time of dying and susceptibility to decomposition. The changes in decomposing material (size structure of particles and nutrient content) mean that detritus in various stages of decomposition differs in its role in trophic dynamics of shore-littoral lake zones. Several types of shore regions as regards detritus sources and retention level are discussed.
Article
The decomposition of several lake macrophytes was investigated under field conditions. Data on weight and phosphorus loss, numbers of microbial decomposers and their activity were obtained. Experiments were conducted in the littoral of two lakes with different levels of macrophyte development. Weight loss during 40-60 days of decomposition for fast-decomposing plants was 60-95% and after 365-day of incubation, Potamogeton perfoliatus L. lost nearly 100% of its initial weight. Slow-decomposing plants lost 20-50% of their initial weight after 40-60 days of incubation, and Phragmites australis (Cav.) Trin. ex Steud. lost 84% of its initial weight after 365 days. Total phosphorus content in plants did not decrease at the first stages of decomposition. Total phosphorus content in plants did not decrease at the first stages of decomposition. The number of microbial decomposers utilizing both labile and resistant substrates increased 2-6 times during the first 5-25 days period. During this period the community was morphologically diverse and biochemically active (high level of microbial respiration). It coincided with the highest weight loss. After that period, the number of microorganisms utilizing labile substrates, as well as the rate of decomposition decreased. The part of macrophyte organic matter entering the biological cycle in two lakes made up 3.5% and 26% of phytoplankton primary production. Bacterial production on decomposing macrophytes was calculated at 4% and 51% of bacterioplankton production, respectively, in both lakes.