Habitat associations of the Threatened pugnose minnow (Opsopoeodus emiliae) at the northern edge of the species range

Pugnose minnow (Opsopoeodus emiliae) is a small, reclusive species that is widespread in North America, but is one of the rarest fishes in Canada, found in less than 12 known localities in southwestern Ontario. In contrast to most pugnose minnow populations across the global range, Canadian populations are primarily found in turbid systems, potentially indicating persistence in suboptimal conditions. We used data from a multi-gear species and habitat survey in the Canard River, Ontario, a system dominated by agricultural inputs and the best-known capture site of the species in Canada, to parameterise multi-gear occupancy models for understanding the relationship between pugnose minnow occupancy and microhabitat features, including the role of turbidity. Almost 300 pugnose minnow were captured, representing the largest single collection of the species in Canadian history. The best occupancy model indicated that the probability of pugnose minnow occupancy was highest in the deepest sites with the lowest water clarity (i.e. high turbidity); however, competing models suggested that occupancy was highest at sites with wild celery (Vallisneria americana) and higher water clarity, signifying that habitats with low turbidity may be utilised if sufficient physical cover exists. Together, our results suggest that Canadian pugnose minnow populations occupy and potentially favour turbid conditions, possibly to avoid visual predators in clearer habitats. It remains uncertain whether this abiotic association represents a long-term, viable, local adaptation or whether persistence of pugnose minnow in the Canard River is at risk unless significant water quality improvements can be made.     

柑橘溃疡病菌LAMP实时浊度检测方法的建立及应用

以柑橘溃疡病菌特异性高的假定蛋白基因（登录号：AE008923.1）为靶标，设计并筛选4条引物来特异性识别靶标序列中的6个独立区域，建立柑橘溃疡病菌LAMP实时浊度检测方法。该方法利用实时浊度仪检测反应过程中产生的焦磷酸镁白色沉淀，实现对LAMP整个反应过程的实时监控。从镁离子浓度、甜菜碱浓度、dNTPs浓度、引物浓度和反应温度5个变量参数对 LAMP检测体系进行优化，并对方法的特异性、灵敏度、稳定性及实际样品检测效果进行评价。结果显示，该体系经优化后稳定性良好，可在66 ℃ 恒温条件下，60 min内完成检测；DNA检测下限可达0.02 ng/μL，灵敏度与荧光定量PCR方法相同，比常规PCR方法高1个数量级；能快速、准确地对田间疑似样品进行检测，与荧光定量PCR方法的检出情况一致，没有漏检。结果说明柑橘溃疡病菌实时浊度LAMP检测方法操作简便、所需时间短，特异性与灵敏度高，为柑橘溃疡病菌的快速筛查提供较好的途径。     

Turbidity‐induced changes in emergent effects of multiple predators with different foraging strategies

Abstract – In natural systems, prey frequently interact with multiple predators and the outcome often cannot be predicted by summing the effects of individual predator species. Multiple predator interactions can create emergent effects for prey, but how those change across environmental gradients is poorly understood. Turbidity is an environmental factor in aquatic systems that may influence multiple predator effects on prey. Interactions between a cruising predator (largemouth bass Micropterus salmoides) and an ambush predator (muskellunge Esox masquinongy) and their combination foraging on a shared prey (bluegill Lepomis macrochirus) were examined across a turbidity gradient. Turbidity modified multiple predator effects on prey. In clear water, combined predators consumed in total more prey than expected from individual predator treatments, suggesting risk enhancement for prey. In moderately turbid water, the predators consumed fewer prey together than expected, suggesting a risk reduction for prey. At high turbidity, there were no apparent emergent effects; however, the cruising predator consumed more prey than the ambush predator, suggesting an advantage for this predator. Understanding multiple predator traits across a gradient of turbidity increases our understanding of how complex natural systems function.     

AlCl_3、FeCl_3和有机物颗粒对淤泥絮凝沉降特性影响

以滇池淤泥的脱水为研究对象,以AlCl3和FeCl3为絮凝剂,在不同絮凝剂加入量系列下（AlCl3浓度取0、1、3、5、7、9、11、13、15mmol/L,FeCl3浓度取0、1、3、5、7、9mmol/L）,研究了AlCl3和FeCl3加入量对淤泥絮凝沉降特性以及清混分界面沉降速度的影响,并选取工农业生产中产量极高...     

智能光纤浊度传感器设计与试验

浊度是指水体中悬浮颗粒的含量，在水产养殖中，悬浮颗粒由大量的细菌、病原体组成，颗粒物浓度过大，易危害水生动物的生存。传统的浊度检测技术易受环境光、色度、温度等因素的影响，稳定性差、精度低。为此设计了基于IEEE1451.2的智能光纤浊度传感器，该传感器由光学检测模块、信号变送模块、智能处理模块组成。光学检测模块采用880nm红外发光二极管作为光源，采用90°散射光检测法，有效降低了色度对浊度检测的影响。信号变送模块采用正向比例积分电路、I/V转换、滤波、检波电路对采集到的散射光电流信号进行处理，得到一个线性关系良好的直流浊度电压信号。为了提高传感器的精确度，设计了基于IEEE1451.2的智能处理模块，构建了温度补偿算法，采用校正TEDS参数完成对浊度的温度补偿，提高了浊度测量的准确度。对传感器性能进行测试试验，结果表明传感器准确度误差在±1.5%以内，稳定性误差在±1.0%以内，满足水产养殖对光纤浊度传感器的需求，具有较高的可靠性。     

Prey‐type‐dependent foraging of young‐of‐the‐year fish in turbid and humic environments

Abstract – Fish, which are generally visual foragers, experiences reduced reaction distance in visually degraded environments, which has consequences for encounter rates with prey. Small prey is detected at shorter distances than larger prey, and piscivores are therefore predicted to be more strongly affected by visual degradation. In experiments, roach (Rutilus rutilus) were fed two plankton prey types and pike (Esox lucius) were fed Daphnia and larval roach, in clear water, algal turbid water and water coloured brown by dissolved organic matter (DOM). Planktivorous foraging in roach was not affected by visual degradation, while pike foraging on both Daphnia and larval roach was. Pike showed increased reaction distance to Daphnia in visually degraded water, while it was severely reduced with roach as prey even if the visual range was not reduced below pike reaction distances in clear water. Pike foraging on Daphnia was not affected, but when foraging on roach, the reduced search efficiency was counteracted by increased attack rates. However, there was no increase in movement and no difference between turbid and DOM treatments. Effects on piscivores will likely become more pronounced at later life stages as prey size and the reliance on long‐distance detection increases at the same time as changing climatic conditions may further deteriorate the visual conditions in future.     

微生物絮凝剂处理淀粉废水

以微生物絮凝剂(MBF7)处理淀粉工业废水.结果表明,在1 L废水中投加质量分数10%的CaCl25 mL,MBF720 mL,在PH9的条件下,分别以600、400、140、70和30 r/min搅拌20s、20s、20s、2 min和3 min时反应条件最佳,浊度去除率高达96.4%.     

基于浑浊度监测山区河流悬浮泥沙含量的试验研究

针对山区河流悬浮泥沙含量监测缺乏实时性的问题,对浑浊度及悬浮泥沙含量进行监测,分析光照强度、流速、颗粒粒径和水体含沙量对浑浊度的影响,建立浑浊度与悬浮泥沙含量的关系模型式。结果表明： 1）光照强度对浑浊度的影响最大,根据二者之间的关系,将光照强度（E）划分为3个区间：E≤6 800 lx、6 800 lx <E≤22 000 lx、E>22 000 lx,对应于3个区间,确定了浑浊度与悬浮泥沙含量的关系模型; 2）水流流速主要影响上层泥沙颗粒的分布,流速为0.16 m/s时测量区域的浑浊度大于流速为0.018 m/s时的浑浊度; 3）泥沙颗粒的粒径大于扬动流速能带动的临界粒径时,其会沉积在渠底,因此,泥沙级配中大于临界粒径的颗粒占比越大,悬浮泥沙含量越小,浑浊度越小; 4）水体含沙量越大,水沙输移过程中携带悬浮泥沙的量也越多,测量区域上层水样的浑浊度越大; 5）采用本研究确定的浑浊度与悬浮泥沙含量的3个关系模型,预测得到的悬浮泥沙含量与实际悬浮泥沙含量的平均相对误差分别为7.22%、10.00%、8.58%。根据在自然条件下不同光照强度区间测得的浑浊度,可以得出该测量区域的悬浮泥沙含量。由于浑浊度可以现场连续、快速测得,所以将此方法引入山区河流悬浮含沙量实时监测是可行的。     

Change in translucency of squid mantle muscle upon storage

ABSTRACT:   Change in the translucency of squid mantle muscle during itsstorage at 0°C was studied by monitoring L* valueand turbidity. Two indicators showed that squid mantle muscle lostits translucency and reached maximal turbidity within 24 hof storage. Thickness of mantle muscle also increased by 15% in12 h, earlier than the loss of translucency. ATP contentdecreased with storage time and was completely lost in almost 24 h,a similar period to translucency loss, but later than rigor contraction.Development of black color on skin surface by chromatophores wasfully achieved in 24 h. It was thus concluded that ATPcontent was well correlated with a loss of translucency or increasein the turbidity of mantle muscle and development of dark coloron the surface skin of mantle.     

应用高光谱数据定量反演查干湖水质参数研究

湖泊水质下降和富营养化问题日益严重,传统监测方法已经日益不能满足水质监测的需要。该文通过野外高光谱仪器测定查干湖水体反射光谱,分析研究水体反射光谱特征与水质参数叶绿素a含量、透明度和浊度之间的关系,运用多种半经验算法建立反演模型。结果表明:单波段光谱反射率与叶绿素a和浊度的相关系数较小,但与透明度相关系数较高;光谱反射率通过对数、比值转换,可以有效的提高叶绿素a和浊度估测模型的精度,却对透明度作用不大。总体来说,叶绿素a和浊度估测模型效果较好,透明度高光谱估测模型相对较差,需进一步研究。