Biogeographic patterns in scaled chrysophytes from the east coast of North America

1. We assessed the distribution of scaled chrysophytes in fresh waters along 3200 km of the east coast of North America (29° to 48°N) to determine any biogeographic patterns in relation to chemical, physical, climatic and spatial variables. 2. Scaled chrysophytes were identified using scanning electron microscopy and counted from 264 waterbodies in nine regions (20 subregions). Eighteen chemical, physical and climate variables were determined for each waterbody. We used Sorensen’s similarity index and analysis of similarity (ANOSIM) to evaluate whether the floras differed between regions, subregions, glaciated and non‐glaciated areas, as well as within sets of waterbodies with similar chemical and physical characteristics but situated in different regions. Distance‐based linear modelling (DISTLM) was used to evaluate the relative importance of the chemical, physical and climate factors in explaining the variability in the assemblages of scaled chrysophytes, and the resulting models were visualised using redundancy analysis (RDA). 3. Significant differences in the flora were found between all regions and most subregions, and between glaciated and non‐glaciated areas. Significant differences were also recorded between waterbodies with similar chemical and physical characteristics but situated in different regions. Many species were abundant along specific sections of the latitudinal gradient, but lacking from others. A set of environmental variables explained significant and independent portions of the variation in scaled chrysophytes, with pH and mean minimum July temperature accounting for 20% of the total. 4. The distribution of scaled chrysophytes along the east coast of North America is not homogeneous and there are biogeographic patterns, despite apparent dispersal mechanisms (migratory birds and wind events) that might act to reduce differences between regions. Rather, differences exist even between neighbouring subregions containing sites with statistically similar chemical and physical attributes. Environmental variables clearly play a significant role in determining whether species will inhabit a given site. However, species were not always found in waterbodies likely to support growth, implicating inadequate dispersal, poor transportability or both.     

Marked recent increases of colonial scaled chrysophytes in boreal lakes: implications for the management of taste and odour events

1. Lake managers suspect that taste and odour‐causing algal blooms are increasing in frequency and intensity, although long‐term monitoring records are scarce, and a number of critical scientific and management questions remain unanswered. 2. In nutrient‐poor lakes and reservoirs, these events are caused primarily by sporadic outbreaks of some chrysophyte algae, which leave identifiable markers in lake sediments. We examine the siliceous remains of these organisms in more than fifty boreal lakes at broad temporal and spatial scales. 3. Colonial scaled chrysophytes, including the taste and odour‐causing Synura petersenii, have increased markedly in more that 90% of the lakes examined since pre‐industrial times. 4. Detailed stratigraphic analyses of two lakes show a rise in the abundance of colonial taxa in the 1930s to 1950s, with a sharp increase over the past two decades. 5. An examination of biogenic silica and biological ratios in Crosson Lake, Ontario, Canada, indicate that these changes represent true increases in the absolute abundance of colonial chrysophytes. 6. Rapid increases over the past two decades indicate that these trends are the result of one or more anthropogenic stressors that are operating at a broad, regional scale.     

Prevalence of otomycosis in malnourished children in Edo State,Nigeria

Out of the total number at 200 suspected cases of otomycoses consisting of 40 malnourished and 160 apparently healthy children examined in this study between the months of July and August in Edo State, 64 Cases (32%) were identified to be of fungal aetiology on the basis of positive culture and careful microscopic exarnination. The state at protein energy malnourishment was deterwined using physicians' comments in their case files. The fungal agents isolated were Aspergillus niger 28 (43.8%); A. fumigatus 4 (25%); Fusarium solari 4 (6.3%); Candida albicans 8 (12.5%); and Hendersonula teruloidea types torn B 5 (6.3%). Of these isolates, A. niger having an solation rate of (43.8%) was found to be the most predominant fungal species associated with otomycosis. This revised version was published online in August 2006 with corrections to the Cover Date.     

Heterotrophic flagellates, centrohelid heliozoa and filose amoebae from marine and freshwater sites in the Antarctic

Heterotrophic flagellates, centrohelid heliozoa and filose amoebae were recorded from cultures derived from water collected at marine and freshwater sites in the Antarctic. Marine samples were collected in the vicinity of Prydz Bay, southeast Antarctica and freshwater samples from Sombre Lake on Signy Island and Crooked and Druzhby Lakes in the Vestfold Hills. Thirty-five species were identified. One new species, Kiitoksia kaloista (Protista incertae sedis), is described. The other species have been previously reported from other geographic locations, providing no evidence for endemism in protozoan species found in Antarctica. Received: 23 September 1996 / Accepted: 28 December 1996     

Physico-chemical and Water Quality Index analysis of the Okhuaihe River,Edo State,Nigeria

The water quality of the Okhuaihe River, Edo State, Nigeria was investigated from February to June 2016 to determine its suitability for drinking and other domestic purposes. Water samples collected from three stations were tested for fifteen physico-chemical parameters using standard analytical procedures. Biochemical oxygen demand and sodium were significantly different across the three stations. Except for calcium and iron, all other parameters were within the permissible limits recommended by the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO). Water Quality Index (WQI) values ranged from 9.17 to 10.40, indicating excellent water quality. Although the quality of the water from the Okhuaihe River is suitable for drinking and domestic usage, regular monitoring of human activities along the water front and control of effluents discharged into the river is recommended to sustain and improve water quality.     

Heterotrophic amoebae,flagellates and heliozoa from Arctic marine waters (North West Territories,Canada and West Greenland)

Summary Thirty eight taxa of heterotrophic protists (amoebae, flagellates and heliozoa) were encountered in cultures established from marine samples from Disko Bay (West Greenland) and Foxe Basin (N.W.T. Canada). Most species are flagellates representing the choanoflagellates, the euglenids, the kinetoplastids, the bicosoecids, the chrysomonads, the pedinellids and a variety of taxa of uncertain affinities (Protista incertae sedis). A new species of thecate choanoflagellate, Salpingoeca intermedia sp. nov., is described, and 4 new types of triangular scales, representing the genus Thaumatomastix Lauterborn, 1899, are presented.     

Phytoplankton of Ogelube Lake,Opi, Anambra State,Nigeria

Ogelube, a small, shallow natural lake at Opi, a township near the University of Nigeria's Nsukka campus yielded 231 algal taxa. Most belonged to the Desmidiales, dominated by Cosmarium, and to the Chlorococcales dominated by Scenedesmus, giving 73 taxa new to West Africa.     

Hooded Vultures Necrosyrtes monachus nearly extirpated from Edo State,Nigeria: a report on the avian scavenger community

Avian scavengers, by feeding on carrion and other organic matter, provide critical ecosystem services. Vultures, the only obligate avian scavengers, have reportedly experienced massive population declines in Africa yet current knowledge regarding their status in most West African countries is unknown. This study set out to ascertain the status of the avian scavenger community in Edo State, southern Nigeria. We made total counts of all scavenging birds at foraging and roosting sites in 13 urban areas. We recorded three species of avian scavenger which were, in order of decreasing relative abundance, Pied Crow Corvus albus, Yellow-billed Kite Milvus migrans and Hooded Vulture Necrosyrtes monachus. There was a positive correlation between relative abundance of avian scavengers and human population size, such that more populous urban centres had larger populations of scavengers. We counted more scavenging birds at roosting sites than at foraging sites. While the Pied Crow and Yellow-billed Kite appear to be thriving in Edo State, the Hooded Vulture appears to have experienced a massive population decline. Our results suggest that without immediate conservation effort such as protection, education and advocacy, the Hooded Vulture will be extirpated from this region in the near future. We suggest that these conservation efforts be focused on the largest urban areas. Furthermore, we recommend that other states in southern Nigeria be urgently surveyed in order for more general conclusions to be drawn about the fate of avian scavengers in this region.     

Nearly circular,oval and irregular holes in Cretaceous ammonoids from Nigeria

Nearly circular‐, oval‐ and irregular‐shaped holes are present in a collection of Late Cretaceous ammonoid cephalopods from southern Nigeria. Two competing hypotheses have been advanced to explain these holes: one is they were produced by diagenetic crushing of limpet home scars and the other is that they are predator's teeth marks. The latter explanation appears to be the best explanation for some of the damage seen in the Nigerian specimens. The suspected predator for some of the specimens was probably an unidentified reptile based on the diameters of the holes. Insofar as we are aware, this is the first recorded predatory damage reported on Cretaceous ammonoids from West‐Central Africa.     

A new cycad subspecies from Nigeria

A new subspecies of the West African Encephalartos barteri is described from plains on the Jos Plateau of northern Nigeria.     

SEM observations of some noteworthy diatoms from the Ikpoba reservoir,Nigeria

ABSTRACT

Eighteen taxa of diatoms from the Ikpoba reservoir, southern Nigeria are listed in this report. They belong to the genera Cymbella, Stenopterobia, Eunotia, Brachysira, Frustulia, Navicula, Pinnularia, Stauroneis and Surirella. The occurrences and distribution of the algae are indicated. Two of these taxa occurred very frequently, six frequently and four occasionally. Five taxa had rare occurrences while one was very rare. They were compared with national as well as regional records.     

Molecular phylogeny, scale evolution and taxonomy of centrohelid heliozoa

Heliozoa are ubiquitous, unicellular phagotrophs with slender radiating axopodia for trapping prey. We sequenced 18S rRNA genes from 35 cultured centrohelid heliozoa (18 studied by electron microscopy) and 28 environmental libraries (18 freshwater, 10 marine), yielding 97 new sequences, this exceeding described species. Phylogenetic analyses show two major groups and that ancestral centrohelids probably had inner plate-like tangential and distinct outer radial silica scales, the latter diverging early into contrasting scale types seen in extant Pterocystis/Choanocystis and Acanthocystis/Raphidiophryidae. Scales were lost at least thrice. Pterocystis is paraphyletic, as was the classical family Acanthocystidae; Heterophrys was polyphyletic. Using scale morphology and rRNA sequences, we establish new families Pterocystidae (Pterocystis, Raineriophrys, Chlamydaster), Marophryidae (type Marophrys (Heterophrys) marina gen. et comb. nov.) and Choanocystidae, new suborders Pterocystina (Pterocystidae, Choanocystidae, Heterophryidae) and Acanthocystina (Acanthocystidae, Raphidiophryidae, Marophryidae), and ten new Pterocystis, Acanthocystis and Choanocystis species. Most clades are exclusively freshwater or exclusively marine; evolutionary transitions between these habitats have been rare.     

Freshwater algae from lakes in the lower Niger Delta system (Nigeria)

Samples from two flood plain lakes (Umuorodog-wum I and II) and one permanent natural lake (Oguta) of the lower Niger Delta system (Imo State, Nigeria), representing the outcome of a single sampling campaign in January 1993, are analysed taxonomically. Emphasis is given on the diatom flora but also on some other accompanying algae; a list of 172 algal taxa is currently presented for the area. The relative species abundance patterns and autecology data confirm the frequent occurrence of taxa capable of tolerating the wide environmental fluctuations determined by local conditions of climate and water chemistry. Comparisons are made between the studied lakes including one disturbed site. The results on the water chemistry and biology corroborate findings from similar ecosystems in West Africa. This revised version was published online in July 2006 with corrections to the Cover Date.     

Freshwater crayfish invasions in South Africa: past,present and potential future

Freshwater crayfish invasions have been studied around the world, but less so in Africa, a continent devoid of native freshwater crayfish. The present study reviews historical and current information on alien freshwater crayfish species introduced into South Africa and aims to indicate which areas are at risk from invasion. As is the case elsewhere, South Africans have shown a keen interest in both farming and keeping freshwater crayfish as pets, which has resulted in Cherax cainii, Cherax destructor, Cherax quadricarinatus and Procambarus clarkii being introduced to the country. There is evidence of successful establishment in the wild for C. quadricarinatus and P. clarkii in different parts of the country. Species distribution models suggest that the eastern part of the country and parts of the Eastern and Western Cape are at higher risk of invasion. At present, illegal translocations represent the most likely pathway of crayfish spread in South Africa. A continued risk of invasion by freshwater crayfish species in South Africa is highlighted, which reinforces the need for more research, as well as for strong mitigation measures, such as stronger policing of existing regulations, management or eradication where feasible and public education.     

Hazardous metals levels in groundwater from Gokana,Rivers State,Nigeria: Non-cancer and cancer health risk assessment

This study investigated heavy metals concentration in groundwater in six coastal communities in Gokana, Rivers State, namely, Gbe, K-Dere, B-Dere, Mogho, Kpor and Bodo City and the human health risk posed to the local populace via ingestion and dermal contact using non-carcinogenic and carcinogenic health risk assessment. The mean values of the heavy metals ranged between 0.02–0.86, 0.16–0.19, 0.03–0.10, 0.02–0.03 and 0.01–0.17 for Mn, Ni, Pb, Cd and Cr, respectively. The heavy metals were above the drinking water quality recommended limits in all the study sites. Estimations of average daily dose (ADD) and dermal absorbed dose (DAD) health risk indicates that Mn, Ni and Pb posed human health risk via ingestion contact pathway. However, hazard index (HI) values of Cd and Cr for ingestion pathway were >1.0 and the estimated Lifetime of Carcinogenic Risks (LTCR) for Ni, Cd and Cr exceeded the predicted lifetime risk for carcinogens of 10^?6 from ingestion pathway. Furthermore, there were more appreciable risk from Ni and Cr in the study sites as LTCR value in most sites were >10^?4_. This study indicates possible non-carcinogenic and carcinogenic human health hazard from groundwater consumption in Gokana via oral ingestion.