Relation between phosphate and organic matter in fish-pond sediments of the Deroua fish farm (Béni-Mellal, Morocco): implications for pond management

An experimental approach of the phosphate exchange across the water–sediment interface in fish ponds of the Deroua farm (Béni-Mellal, Morocco) is needed to understand the phosphate dynamics in these ponds in relation to their water quality. During this study, we conducted experiments to determine the P-fractions of the different pond sediments and to estimate the release from these sediments of phosphate available for algal uptake. We also determined the amount of phosphate needed to saturate the sediments of two different fish ponds under anoxic and oxic conditions. Phosphate release from sediments comes mainly from Fe(OOH)P and is more important in ponds lined with sheets. The accumulation of organic matter in sediments favours the installation of anoxic conditions and enhances the phosphate release from CaCO₃P, labile in these pond sediments. Under experimental conditions, org-P plays a minor role in the P-release. Oxic conditions, to the contrary, have an inhibitory effect on the P-release from sediments. About 80–98% of the P-adsorbed onto different pond sediments was recovered in the inorg-P-fractions. Aeration induces the oxidation of FeS to Fe(OOH) which can adsorb phosphate from solution. Besides, the presence of bacteria in pond sediments was essential to promote phosphate release under anoxic conditions by controlling the oxidation state of iron and the mineralization of the organic matter. Sheet-lined ponds, when insufficiently dried, accumulate a large quantity of organic matter in their sediments. After a decrease in pH, P is released from CaCO₃P and enhances the phytoplankton productivity responsible for renewed accumulation of organic matter. Org-C concentrations in sediments over 20 mg g^–1 d.w. favour the formation of toxic factors (Fe²⁺, Mn²⁺, NO₂ ^– and H₂S) harmful for carp growth. An extended period of drying efficiently enhances the mineralization of organic matter.     

Changes in sediment phosphate composition of seasonal ponds during filling

Most ponds from the Doñana National Park are shallow temporary freshwater bodies on eolian sands. The total phosphate concentration and the fractional P-composition of the sediments from two small ponds were studied before and inmediately after they were filled (autumn, 1996). Total phosphorus concentration was measured in 2 different size fractions: 2–0.1 mm (coarse) and <0.1 mm (fine). In both ponds, the total phosphorus concentration of the fine sediment increased by 20% at the beginning of the filling period, whereas 5 weeks later it did not increase further. The percentage of organic matter of the fine sediment was relatively high (between 13–18%) and did not change significantly during filling. The concentration of sediment total iron and Fe(OOH) increased significantly in both ponds during filling. The sequential P fractionation of the fine sediment included, besides the determination of two inorganic fractions (Ca-bound P and Fe-bound P), an organic-P fraction extracted with acid, another extracted with alkali, two organic-P fractios from the Ca-EDTA/dithionite and the Na₂-EDTA extracts which contained high concentrations of humic substances. The pond sediments were rich in organic P compounds as the sum of all organic-P fractions ranged between 267 and 320 g g^-1 (68% and 79% of the sum of all fractions). Significant changes (P<0.01) in the fractional P-composition of sediments were found after filling. Acid soluble organic phosphate increased about 30% in both ponds. Iron-bound phosphate increased significantly (about 40%) only in the pond where a higher concentration of Fe(OOH) was measured after filling. An adsorption experiment was carried out for each sediment to simulate P input during filling. Both the iron-bound phosphate and Ca-bound P increased significantly (P<0.01) suggesting that these two fractions were involved in the P-adsorption during the laboratory experiment.     

Seasonal variations of P compounds and their concentrations in two coastal lagoons (Herault,France)

This article concerns seasonal variations in the phosphate concentrations in two coastal lagoons near Montpellier (Mediterranean coast, France). The o-P concentration in the overlying water is highest during summer. The role of the sediment, particularly that of the different P fractions in the sediment, is discussed. Significant variations, especially in the FeOOH ≈ P fraction, occur. For both Tot-P_sed and the Fe00H≈P fraction a gradient from surface to bottom is observed, as well as a distinct decrease in the FeOOH≈P fraction in the surface sediments during summer and autumn. Variations in the FeOOH≈P fraction appear to be compensated by variations in the CaC0₃≈P fraction. These variations appear to be determined by the ferric hydroxide concentration. This compound represents only a small part (maximally 15%) of the total iron in the sediments and is related to the dissolved oxygen content of the immediately overlying water. Besides the fractions o-P, Fe(OOH)≈P, a large part of the CaC0₃≈P fraction is potentially bioavailable. A large proportion of the Tot-P_sed is therefore bioavailable.[/p]     

重庆丘陵山区池塘沉积物有机碳埋藏速率及其影响因素

池塘等小型水体在全球碳循环中发挥着重要作用,是碳排放的热区,但是对池塘碳埋藏速率认识相对匮乏,限制了全面认识池塘在流域碳传输中的功能。为探究池塘沉积物有机碳埋藏速率及其影响因素,选取重庆市北碚区柳荫镇的11个池塘为研究对象,于2022年7月对池塘沉积物进行采样,分析了池塘沉积物基本理化性质,估算出池塘沉积物有机碳埋藏量和埋藏速率,并分析了池塘因素和流域因素对池塘沉积物有机碳埋藏速率的影响。结果显示：(1)沉积物总有机碳(TOC, Total Organic Carbon)含量在1.03%—3.51%之间变化,总体呈现随深度增加而逐渐降低的趋势;(2)有机碳埋藏速率均值为194.60 g m^-2 a^-1,范围区间为142.76—293.32 g m^-2 a^-1,略高于其他池塘的类似研究结果;(3)沉积物TOC含量与总氮(TN, Total Nitrogen)含量呈显著正相关(P<0.01),与流域中林地面积占比呈显著正相关(P<0.05),与旱地面积占比呈显著负相关(P<0.05),...     

盐城自然保护区两种人工湿地模式评价

在用能值分析对盐城自然保护区两种人工湿地研究的基础上 ,对其可持续发展提出了建议。在缓冲区建立以获取经济效益为目的的鱼塘是必要的 ,它为自然保护事业的发展提供了足够的资金反馈 ;为了减轻由于湿地开发带来的珍禽的生境压力 ,在核心区的边缘必须建立以招鸟为目的的水禽湖。水禽湖对鱼塘的面积比须在 0 .1 9和 8.0 0之间。当比例是0 .1 9时 ,系统获得最大经济效益 2 .1 3× 1 0 3US＄ /a.hm2 ,当比例是 8.0 0时 ,系统获得最大生态效益 1 .1 8× 1 0 3US＄ /a.hm2当比例是 0 .3 1时 ,系统获得相等的生态和经济效益 ,其和是 3 .79× 1 0 2 US＄ /a.hm2 比例 0 .3 1是保护区较优的选择。在此模式运作几年后 ,鱼塘须被改成水禽湖 ,且被划入核心区进行严格管理 ,核心区被扩大。同时 ,建议在江苏省“海上苏东”发展计划对海涂湿地大力开发的同时 ,必须建立一定比例的适于珍禽栖息活动的人工湿地 ,扩大自然保护规模 ,以保护珍贵的生物多样性资源。     

Intermediate Pond Sizes Contain the Highest Density,Richness, and Diversity of Pond-Breeding Amphibians

We present data on amphibian density, species richness, and diversity from a 7140-ha area consisting of 200 ponds in the Midwestern U.S. that represents most of the possible lentic aquatic breeding habitats common in this region. Our study includes all possible breeding sites with natural and anthropogenic disturbance processes that can be missing from studies where sampling intensity is low, sample area is small, or partial disturbance gradients are sampled. We tested whether pond area was a significant predictor of density, species richness, and diversity of amphibians and if values peaked at intermediate pond areas. We found that in all cases a quadratic model fit our data significantly better than a linear model. Because small ponds have a high probability of pond drying and large ponds have a high probability of fish colonization and accumulation of invertebrate predators, drying and predation may be two mechanisms driving the peak of density and diversity towards intermediate values of pond size. We also found that not all intermediate sized ponds produced many larvae; in fact, some had low amphibian density, richness, and diversity. Further analyses of the subset of ponds represented in the peak of the area distribution showed that fish, hydroperiod, invertebrate density, and canopy are additional factors that drive density, richness and diversity of ponds up or down, when extremely small or large ponds are eliminated. Our results indicate that fishless ponds at intermediate sizes are more diverse, produce more larvae, and have greater potential to recruit juveniles into adult populations of most species sampled. Further, hylid and chorus frogs are found predictably more often in ephemeral ponds whereas bullfrogs, green frogs, and cricket frogs are found most often in permanent ponds with fish. Our data increase understanding of what factors structure and maintain amphibian diversity across large landscapes.     

Evaluation of Aerial Cluster Sampling of Double-Crested Cormorants on Aquaculture Ponds in Mississippi

Abstract Concern over increasing numbers of double-crested cormorants (Phalacrocorax auritus) and their impacts on channel catfish (Ictalurus punctatus) aquaculture has resulted in increased need for quantitative information to develop and evaluate depredation management efforts. We evaluated aerial surveys in a stratified cluster sampling (SCS) design to estimate and monitor abundance of cormorants on catfish aquaculture ponds in the Yazoo River Basin of Mississippi, USA (hereafter Yazoo Basin). Twice monthly abundance estimates and coefficient of variation during winter averaged 8,128 (n = 29, SE = 1,233) and 33% (n = 29, SE = 0.02), respectively. Counts of cormorants on catfish aquaculture ponds between survey years were correlated (r = 0.87, n = 28). The correlation between diurnal counts of cormorants on ponds and cormorant night roost counts was 0.64 in 2000–2001 and 0.58 in 2003–2004 (n = 20 in both years). A priori estimates of sample size indicated an average increase in sampling effort of 39% during peak periods of cormorant use would be necessary to detect a ±15% change in cormorant abundance on aquaculture ponds at α = 0.05 and β = 0.80. The sampling design we used has the potential to be an effective tool for providing quantitative information on cormorant abundance on catfish aquaculture ponds in the Yazoo Basin. However, increased sampling effort would be necessary to obtain desired levels of precision. The SCS design we evaluated represents only one of many possible survey methods, and we recommend additional evaluation of this method and related survey methods.     

Sexual reproduction and diapause of Hexarthra sp. (Rotifera) in short-lived ponds in the Chihuahuan Desert

1. In the life cycle of monogonont rotifers it is generally assumed that diapausing eggs invariably hatch into amictic stem females which produce female offspring parthenogenetically. Diapausing eggs are only produced by later generations after sexual reproduction has been induced by environmental cues. 2. We show that populations of an undescribed Hexarthra species inhabiting small temporary ponds in the Chihuahuan Desert deviate from this life cycle pattern. These ponds may dry within days and up to 85% of females were mictic. Females producing male offspring and diapausing eggs were observed 1 or 2 days, respectively, after ponds had filled with water. 3. Under laboratory conditions, 7–46% of females hatching from re‐hydrated sediments were sexual. Male offspring of these females can fertilise other mictic stem females leading to diapausing egg formation. In laboratory experiments, females produced fully developed diapausing eggs within 1.9 days at 20 °C and 1.2 days at 30 °C. 4. In addition, embryonic development time (1.1–0.3 days at temperatures between 12 and 30 °C) and juvenile period (2.1–0.5 days for the same temperature range) are shorter than those of other rotifer species. In short‐lived habitats, the potential for rapid population development and production of new diapausing eggs may be crucial in the long‐term survival of populations.     

The spatial and temporal heterogeneity of macrophyte communities in thirty small,temporary ponds over a period of ten years

Ponds are important habitats within many landscapes because of the diversity of wildlife they support. This arises in part because of the heterogeneity of ecological communities found in neighbouring ponds but this variation has proved difficult to explain. Chance and unrecorded historic events have often been emphasised as explanations. This study describes the development of spatial heterogeneity and the role of historic events in the development of pond plant macrophyte communities from the ponds’ creation until ten later using thirty small, adjacent temporary ponds in Northumberland. Plant communities showed significant spatial variation from the first year onwards. Metacommunity spatial patterns changed over time but even after ten years several distinct macrophyte communities persisted in different ponds. The outcome was that a greater variety of pond communities persisted than was likely if a single, larger pond had been created on the site. The spatial patterns of the plants communities were compared to spatial variation of summer dry‐phase and winter inundation. Macrophyte heterogeneity appeared to result from deterministic change which would have been difficult to detect in a snap‐shot survey not knowing the history of the ponds. Winter inundation showed significant spatial trends every year which mirrored the changing distribution of macrophyte communities between ponds. The proximate influence of the inundation is ultimately determined by the position of each pond in the landscape so that the marked spatial and temporal heterogeneity of plant communities was strongly influenced by small scale variation in hydrology. The results suggest that the heterogeneity of pondlife across a landscape may be deterministic when recorded over a longer time period and not due to chance, but that the determining environmental factors are highly contingent on the locality of the pond.     

Next‐Generation Sequencing Assessment of Eukaryotic Diversity in Oil Sands Tailings Ponds Sediments and Surface Water

Tailings ponds in the Athabasca oil sands (Canada) contain fluid wastes, generated by the extraction of bitumen from oil sands ores. Although the autochthonous prokaryotic communities have been relatively well characterized, almost nothing is known about microbial eukaryotes living in the anoxic soft sediments of tailings ponds or in the thin oxic layer of water that covers them. We carried out the first next‐generation sequencing study of microbial eukaryotic diversity in oil sands tailings ponds. In metagenomes prepared from tailings sediment and surface water, we detected very low numbers of sequences encoding eukaryotic small subunit ribosomal RNA representing seven major taxonomic groups of protists. We also produced and analysed three amplicon‐based 18S rRNA libraries prepared from sediment samples. These revealed a more diverse set of taxa, 169 different OTUs encompassing up to eleven higher order groups of eukaryotes, according to detailed classification using homology searching and phylogenetic methods. The 10 most abundant OTUs accounted for > 90% of the total of reads, vs. large numbers of rare OTUs (< 1% abundance). Despite the anoxic and hydrocarbon‐enriched nature of the environment, the tailings ponds harbour complex communities of microbial eukaryotes indicating that these organisms should be taken into account when studying the microbiology of the oil sands.     

Breeding pond fidelity in the common toad, Bufo bufo

Two independent studies of adult common toad, Bufo bufo , movements between different spawning ponds/populations both within and between years were made in England and Sweden during the spring breeding periods of1987–1990. The results of the two studies were subsequently combined since they were found to be complementary. In addition, in England during 1984 and 1985, large numbers of 'toadlets' were marked so that they could be identified if recaptured as breeding adults.
The degree of relocation between ponds was negatively correlated to the distance between ponds. The proportion of both males and females that moved between ponds within a particular year was significantly less than the proportion relocating between years. In any year, between 79% and 96% of adults that survived to breed the following year, returned to the original pond. Similarly, of the toadlets marked during1984–85, 81% of the males that subsequently returned as breeding adults were captured in their pond of origin.
Isolation, in relation to both population dynamics and population genetics, is defined and its implications for the management of common toad populatins discussed.     

亚热带河口养殖塘沉积物有机碳矿化及其影响因子

亚热带河口的养殖塘是温室气体二氧化碳(CO2)的重要排放源,但其沉积物有机碳矿化动力学特征目前尚未厘清.以我国东南沿海亚热带闽江、木兰溪以及九龙江河口区的6个凡纳滨对虾(Penaeus vannamei)养殖塘为研究对象,对沉积物取样,并进行为期60 d的室内厌氧培养,对养殖塘沉积物CO2累积产量曲线利用一阶动力学模型...     

Effects of hydrology on zooplankton communities in high-mountain ponds, Mount Rainier National Park, USA

Ten high-mountain ponds in Mount Rainier National Park, WashingtonState, were studied from ice-out in June through September1992to investigate the influences of fluctuating pond volumes onzooplankton communities. All of the ponds were at maximum volumeimmediately after ice-out. The temporary pond with the shortestwet phase was inhabited by rotifer taxa with short generationtimes and a crustacean taxon with the ability to encyst as drought-resistantresting bodies at immature stages of development. Dominant zooplanktontaxa in three other temporary ponds and six permanent pondswere similar. Rotifer densities typically were lower in temporaryponds relative to those in permanent ponds, although Brachionusurceolaris was abundant shortly before the temporary ponds dried.Large volume loss was associated with large declines in totalabundances of crustacean populations. Daphnia rosea was notpresent in temporary ponds following fall recharge. In deep-permanentponds, copepods had slower developmental rates, smaller temporalchanges in total abundances of crustacean populations and twoadditional large-bodied crustacean taxa were present relativeto the characteristics of crustacean communities in shallow-permanentponds. Owing to their small sizes and sensitivity to environmentalchange, collectively ponds such as these may provide an earlysignal of long-term climate change in aquatic systems.     

Fish growth enhances microbial sulfur cycling in aquaculture pond sediments

Microbial sulfate reduction and sulfur oxidation are vital processes to enhance organic matter degradation in sediments. However, the diversity and composition of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) and their environmental driving factors are still poorly understood in aquaculture ponds, which received mounting of organic matter. In this study, bacterial communities, SRB and SOB from sediments of aquaculture ponds with different sizes of grass carp (Ctenopharyngodon idellus) were analysed using high-throughput sequencing and quantitative real-time PCR (qPCR). The results indicated that microbial communities in aquaculture pond sediments of large juvenile fish showed the highest richness and abundance of SRB and SOB, potentially further enhancing microbial sulfur cycling. Specifically, SRB were dominated by Desulfobulbus and Desulfovibrio, whereas SOB were dominated by Dechloromonas and Leptothrix. Although large juvenile fish ponds had relatively lower concentrations of sulfur compounds (i.e. total sulfur, acid-volatile sulfide and elemental sulfur) than those of larval fish ponds, more abundant SRB and SOB were found in the large juvenile fish ponds. Further redundancy analysis (RDA) and linear regression indicated that sulfur compounds and sediment suspension are the major environmental factors shaping the abundance and community structure of SRB and SOB in aquaculture pond sediments. Findings of this study expand our current understanding of microbial driving sulfur cycling in aquaculture ecosystems and also provide novel insights for ecological and green aquaculture managements.     

Taphocenoses of temporary ponds in the steppe zone of European Russia by algo-zoological analysis of recent sediments

Subfossil algae and invertebrates in the surface sediments of 26 small ponds in Saratov and Volgograd regions have been studied. Algo-zoolgical analysis of recent (surface silt) sediments has been performed. The characteristic features of taphocenoses in temporary ponds of the region under study are revealed, which distinguish them from proportionate ponds in the forest zone. It is found that sediments in the studied temporary ponds are characterized by low concentrations and diversity of biological remains, with the dominance of diatom frustules; Testacea, Ostracoda, and Spongilla sp. spicules are the predominant zoogenic remains. It is revealed that additional subfossil material can be obtained by rinsing sediments and analyzing sieve residues.     

Development and practical application of limiting values for the phosphate concentration in surface waters in the Netherlands

Summary To counteract eutrophication it is important to possess sufficient information (1) on the relationship between the content of nutrients and the algal biomass, and (2) on the cycling of nutrients in lakes.A comparative study of a large number of surface waters in the Netherlands has demonstrated that it is possible to derive a relationship between the nitrogen and phosphorus concentrations and the upper limit of the chlorophyll concentration, averaged over the summer season.For the authority in charge of water quality it is essential to know how far the phosphorus loading must be reduced to attain the desired phosphate concentration. The results of an extensive study of the nutrient budgets of Lake Wolderwijd-Nuldernauw over the period 1976–1979 demonstrate that in certain cases a relative high phosphate concentration can occur (approx. 0.30 mg/l) in spite of a low external phosphorus loading (approx. 0.7 g P/m² year). Such high concentrations can be explained by the continuous presence of a bloom of blue-green algae and the release of phosphate from the aquatic sediments during the summer. In such lakes it is necessary to take additional measures, such as flushing with water poor in algae and phosphates, or, where necessary, the removal of aquatic sediment rich in phosphate.     

A small dredge for sampling aquatic macrophytes

A small dredge for sampling of aquatic macrophytes in shallow lakes, ponds and rivers is described. The dredge consists of a crown-like stainless steel vessel, disk and legs. The total dredge weight is 550 g. The dredge is useful for sampling higher plants, water ferns, mosses, liverworts and large algae, and for sampling soft sediments.     

Seed Banks and Species Richness Potential of Coal Slurry Ponds Reclaimed as Wetlands

Seed bank experiments are described to assess the species richness potential of coal slurry ponds reclaimed as wetlands (ranging from 6 to more than 40 years old). Experimental treatments test the drawdown and flooded conditions characteristic of the vegetation dynamics of emergent wetlands in the Upper Mississippi Valley. More seedlings, primarily annuals, emerged from exposed wet sediments (freely drained) than under continuous flooded sediments in cold ponds (339 versus 136 seedlings m^?2, respectively) and in natural ponds (163 versus 47, respectively). More seeds were produced by plants established in freely drained conditions than under flooded conditions from sediments in the coal ponds (26546 versus 1842 seeds m^?2, respectively) and the natural ponds (28430 versus 4526, respectively). Similarly, more biomass was also produced by these plants in freely drained than under flooded conditions in coal ponds (118 versus 47 g m^?2, respectively) and natural ponds (118 versus 52, respectively). Fertilization (NPK) did not affect germination for the most part, but it did affect seed set and biomass production, especially for C₄ annuals such as Echinochloa crusgalli and Panicum dichotomiflorum. I propose that lime (calcium carbonate) and fertilizer be applied during the first few scheduled drawdowns for these coal slurry ponds reclaimed as wetlands to increase the number of species and to allow their more rapid development as self-sustaining systems.     

Spatial and seasonal distribution of heterotrophic bacteria in pond water and sediments under different management practices

Population densities and generation time of heterotrophic bacteria were estimated in water and sediments of fish ponds used for polyculture, monoculture and traditional systems of fish farming over a period of two and a half years. Spatial differences in microbial densities in the ponds were related to the organic loadings of the farm site and farm management. A number of environmental factors such as nitrogen, dissolved organic carbon, bicarbonate and phosphate of water were found to be responsible for the seasonal changes of heterotrophic bacteria in these ponds.