Importance of nonindigenous harpacticoids (Crustacea: Copepoda) decrease with depth in Lake Ontario

Harpacticoid copepods can be a substantial component of the meiobenthic community in lakes and serve an ecological role as detritivores. Here we present the first species-level lake-wide quantitative assessment of the harpacticoid assemblage of Lake Ontario with emphasis on the status of nonindigenous species. Additionally, we provide COI-5P sequences of harpacticoid taxa through Barcode of Life Data System (BOLD). Harpacticoids were collected at depths from 0.1 to 184 m and from a range of substrates from August to September 2018 as part of the Cooperative Science and Monitoring Initiative (CSMI) offshore benthic survey. Twenty-six meiobenthic samples were analyzed using microscopy for community composition analysis of harpacticoids. We found thirteen indigenous and three nonindigenous species of harpacticoid, with the introduced species dominating at shallow depths. The community transitioned from nonindigenous to indigenous species dominance as depth increased. Nonindigenous species accounted for 79% of the community (by abundance) at depths <20 m, 55% from 20 to 40 m, and only 24% at depths >40 m. The nonindigenous species encountered included the first detections of Schizopera borutzkyi (Monchenko, 1967) and Heteropsyllus nunni (Coull, 1975) from Lake Ontario. S. borutzkyi was the most abundant harpacticoid species in the lake, approaching a maximum density of 50,000/m² and a lake-wide average density of 7,900/m². Numerically important indigenous species included Bryocamptus nivalis (Willey, 1925), Canthocamptus robertcokeri (Wilson, 1958), Canthocamptus staphylinoides (Pearse, 1905), and Moraria cristata (Chappuis, 1929). The prevalence of nonindigenous harpacticoids in the meiobenthos of Lake Ontario suggests further investigations of Great Lakes meiofauna communities are warranted.     

Modeling the pathways and attenuation of nutrients from domestic wastewater treatment systems at a catchment scale

Domestic Wastewater Treatment Systems (DWTS) are often cited as significant sources of pollution in rural catchments. A mass balance based model has been developed to determine annual nutrient loading from individual DWTS into rivers in Ireland. The transport and attenuation of nitrogen and phosphorus in DWTS effluent to groundwater and surface water has been formulated using the results from field research in Ireland, as well as being informed by other international studies. Conceptually the model splits the transport of nutrients to the river into three pathways: direct to surface water (for areas of inadequate percolation), a near surface (subsoil) pathway, and a groundwater pathway. The model quantifies the net nutrient contribution for each DWTS and has been incorporated into a broader source load apportionment catchment model which includes agricultural inputs, thereby enabling the relative risk of nutrient pollution from DWTS in a catchment to be defined.     

Shared orchestration within and beyond the classroom

With the introduction of personal computer devices such as smartphones and tablets into school classrooms, teachers have the added task of orchestrating complex dynamic systems of students interacting with networked technologies. One approach to managing the interactions is to add an orchestration system that enables a teacher view and control each student device. An alternative is to share responsibility for orchestration between the teacher, the students, and the technology. In this form of orchestration, the teacher and all the students have similar computer toolkits designed to guide the students through a productive learning activity. An advantage is that the teacher can hand over control to the students to continue the learning activity outside the classroom, assisted by the Activity Guide software.     

Biodiesel Production Using a Carbon Solid Acid Catalyst Derived from β‐Cyclodextrin

A novel carbon solid acid catalyst was prepared by incomplete hydrothermal carbonization of β‐cyclodextrin into small polycyclic aromatic carbon sheets, followed by the introduction of –SO₃H groups via sulfonation with sulfuric acid. The physical and chemical properties of the catalyst were characterized in detail. The catalyst simultaneously catalyzed esterification and transesterification reactions to produce biodiesel from high free fatty acid (FFA) containing oils (55.2 %). For the as‐prepared catalyst, 90.82 % of the oleic acid was esterified after 8 h, while the total transesterification yield of high FFA containing oils reached 79.98 % after 12 h. By contrast, the obtained catalyst showed comparable activity to biomass (such as sugar, starch, etc.)‐based carbon solid acid catalyst while Amberlyst‐15 resulted in significantly lower levels of conversion, demonstrating its relatively high catalytic activity for simultaneous esterification and transesterification. Moreover, as the catalyst can be regenerated, it has the potential for use in biodiesel production from oils with a high FFA content.     

Minimum time problem synthesis

The use of the non-standard analysis techniques has proved very useful in treating singular perturbation of ordinary differential equations (see the survey paper [12]). The idea that non-standard analysis should provide interesting tools in optimal control is not new (see for instance [1]). In this paper, written from the authors' thesis [8], it is shown that optimal control problems lead to interesting non-standard Hamiltonian systems.     

青海湖湖滨湿地演变与驱动因素分析

为了更好地应对气候变化的影响,对暖湿化气候下青海湖湖滨湿地的演变现状及其驱动因子进行研究。通过遥感影像解译和水文分析计算结合实地调查,发现21世纪气候暖湿化进程下,青海湖水位升高2.1 m,入湖水量显著增加。2003—2016年的年均径流量比1956—2002年的年均径流量增加了6.0亿m3,湖面降水增加了3.8亿m3,从最低水位到现状水位的湖滨淹没区面积为222 km2。湖滨区的地下水位抬升,地势较低的河谷区沼泽草甸面积扩大11.7 km2,溢出泉恢复,间歇性河流增加了近30条,间歇性湖泊(泡沼)恢复到1980年初的水平。同时,湖水位上升淹没了约23 km2的湖滨沼泽和鸟岛部分区域,植被腐殖质、食物碎屑和鸟类沉积粪便进入湖泊,加之畜牧业和旅游业的发展,牲畜粪便和垃圾流入青海湖,导致水深和光照适宜的湖滨区爆发刚毛藻水华。     

Phytoplankton functional groups in a high spatial heterogeneity subtropical reservoir in China

Traditional classification of phytoplankton assemblages does not adequately reflect their ecological function in aquatic ecosystems. Therefore, we used a functional group approach based on the Q index to analyze the spatial and temporal patterns, environmental factors and the ecological status of phytoplankton in the Danjiangkou Reservoir (DJKR) of China in July 2011 to April 2012. Groups B (Cyclotella species), C (Asterionella formosa and Cyclotella meneghiniana), D (Stephanodiscus hantzschii, Synedra acus and Nitzschia sp.), Lo (mainly Peridiniopsis spp.), P (Fragilaria capucina and Aulacoseira spp.) and Y (Cryptomonas ovata and Cryptomonas erosa) were classified as dominant phytoplankton functional groups. We ran redundancy analysis and Pearson correlation analysis to assess the relationship between functional groups and environmental factors. Total phosphorus, pH and soluble silicate were apparently the key factors driving variation in phytoplankton functional groups. The analyses suggest P-limitation of phytoplankton growth. The Q index based on functional groups indicated the relatively good ecological status of the DJKR which varied as a function of the mixing regime; most samples were scored as medium or high quality according to the Q index evaluation (Q > 2). This is the first application of the assemblage index to a water supply reservoir for the Middle Route Project (MRP) for South-to-North Water Transfer (SNWT) in China.     

Fast bio-inspired computation using a GPU-based systemic computer

Biology is inherently parallel. Models of biological systems and bio-inspired algorithms also share this parallelism, although most are simulated on serial computers. Previous work created the systemic computer – a new model of computation designed to exploit many natural properties observed in biological systems, including parallelism. The approach has been proven through two existing implementations and many biological models and visualizations. However to date the systemic computer implementations have all been sequential simulations that do not exploit the true potential of the model. In this paper the first ever parallel implementation of systemic computation is introduced. The GPU Systemic Computation Architecture is the first implementation that enables parallel systemic computation by exploiting the multiple cores available in graphics processors. Comparisons with the serial implementation when running two programs at different scales show that as the number of systems increases, the parallel architecture is several hundred times faster than the existing implementations, making it feasible to investigate systemic models of more complex biological systems.     

氮、磷对缺刻蚁形藻生长、总脂及花生四烯酸积累的影响

目的:研究缺刻蚁形藻(Myrmecia incisa)在4种氮、磷质量浓度条件下的生长和总脂(TL)及花生四烯酸(AA)含量,以及在低氮和低磷条件下的脂肪酸组成。方法:采用BG-11培养基和Φ6×60cm柱状光生物反应器培养缺刻蚁形藻,利用有机溶剂提取脂类物质,通过气相色谱-质谱仪分析脂肪酸的组成。结果:在300～1500mg/L的硝酸钠质量浓度范围内,氮质量浓度的改变对缺刻蚁形藻的生物量影响不明显,不同氮质量浓度条件下的最终生物量在2.10～2.40g/L之间。低氮质量浓度条件下TL和AA含量最大,分别为藻粉干质量的27%和总脂肪酸(TFA)的9.04%,其中AA占藻体干质量的3.16%。不同磷质量浓度对缺刻蚁形藻的生长影响显著,低磷质量浓度明显抑制藻的生长,其最终生物量在0.98～2.47g/L之间。在质量浓度8～20mg/L的磷酸氢二钾条件下,藻的TL含量没有明显变化,为20%左右。结论:TL与氮、磷质量浓度呈明显负相关关系,低氮比低磷条件更有利于AA的积累。