Although the process by which fertilization occurs in bryozoans is well described, the ability to self-fertilize and the subsequent ecological consequences are poorly understood. Culturing experiments were conducted examining the effects of selfing on offspring survival and reproduction in the simultaneous hermaphrodite Bugula stolonifera collected from Eel Pond, Woods Hole, MA. Results from these experiments document significant decreases in survival and fecundity of selfed offspring, compared to outcrossed controls, suggesting that these animals are not routinely self-fertilizing in Eel Pond. How these arborescent colonies minimize selfing remains unclear, but it is hypothesized that conspecific aggregations could serve to minimize the chances that a colony utilizes its own sperm for fertilization. The genetic composition of these aggregations was investigated using a newly developed microsatellite library. As larvae routinely metamorphose on conspecific colonies, the possibility that larvae select or avoid their maternal colony was also investigated. Analyses of genetic structure document homogeneity throughout these aggregations on extremely small spatial scales, suggesting high amounts of larval dispersal within aggregations. When combined with results from parentage-exclusion and kinship analyses, these results indicate that a colony's nearest neighbors are not composed of siblings, potentially minimizing inbreeding. Molecular analyses were then used to determine if the high larval dispersal within aggregations resulted in high mixing between aggregations. Sites within Eel Pond separated by 100-300 m were routinely sampled from 2009 to 2011, and analyses were conducted to investigate potential inter- and intra-annual genotypic differentiation within and between aggregations. Results document that although low levels of mixing could result in increased homogeneity between some aggregations, barriers to genetic exchange prevent mixing between most sites. Further, inter-annual comparisons within sites document that significant differentiation can occur between reproductive seasons. Hence, any potential homogeneity achieved between sites during one reproductive season will likely be lost by the beginning of the next reproductive season. Additionally, while sampling in Eel Pond in 2010, I document the first occurrence from the western Atlantic Ocean of another aggregating arborescent bryozoan, Tricellaria inopinata. The growth and reproductive biology of these animals was monitored throughout 2011; results suggest that this introduction is likely to persist.

No description available.

The aim of this thesis has been to: 1) assess the state of pollution in the two study areas and relate them to recent changes found in the Kattegat - Belt Sea area; 2) examine the observed spatial and temporal variability in species composition, abundance and biomass in Arhus Bay and the Formes area and relate the variability to antropogenic and natural causes; 3) discuss and assess methods, particularly for the estimation of secondary production and the use of multivariate analyses as methods for examining changes in macrozoobenthic communities. Macrozoobenthos were sampled at 15 stations in Arhus Bay, Denmark from 1985 to 1991 while data from Formes (reference area) included 55 sampling stations from 1986 to 1990. Monthly sampling took place at one station in Arhus Bay in 1990 and 1991. The two study areas are both situated on the eastcoast of Jutland in the Kattegat - Belt Sea area at 13-17 m depth and both receive waste water from long sea outfalls. Although both areas are Subjected to salinity stratification for most of the year, the exposed position of the Formes area on the open Kattegat coast prevents it from suffering from severe oxygen deficiencies, unlike the Arhus Bay which is a sheltered, semi-enclosed sedimentation area where oxygen concentrations in the bottom water can be very low. At Formes the sediment is sandy while it is silty in Arhus Bay. The spatial and temporal variability in the benthos in Arhus Bay could to a great extent be explained by the variation in 7 important species: Abra alba, Corbula gibba, Mysella bidentata, Nepthys hombergii, N. ciliata, Ophiura albida and Echinocardium cordatum. The fluctuations in the number and biomass of A. alba had a pronounced effect on the total abundance and biomass in Arhus Bay. The severe winter of 1986/87 with low temperatures and oxygen depletion under the ice cover practically eliminated A. alba from the bay. A. alba quickly recolonized the area and was found in high numbers in 1988. Studies of growth of A. alba in 1990 and 1991 showed that by the end of 1990 the population had reached an average length of 10 mm while the average shell length was only 5 mm by the end of 1991. The difference between the two years could be attributed to the difference in sedimentation of phytoplankton from the water column. As in other parts of the Kattegat - Belt Sea area, Arhus Bay has experienced low oxygen concentrations in the bottom water in late summer early autumn throughout the 1980s. Only the oxygen depletion under the ice cover in early spring 1987 and the local oxygen deficiencies south of the outlet in 1989 and 1990 actually killed parts of the benthic fauna. Apart from 1981, the oxygen deficiencies have thus been less severe in Arhus Bay than in other parts of the southern Kattegat in the 1980s. The number of species, abundance and biomass decreased at Fornres from 1980 to 1985 while the discharge of BOD was fairly constant during the same period. From 1986 there was a slight decrease in the discharge of BOD but a considerable increase in the number of species, abundance and biomass. At least for the second half of the 1980s there was no straightforward relation between the organic enrichment from the outlet and species composition, abundance and biomass and suggests that other factors are also important influencing the fluctuations in the benthic fauna. Estimates of total secondary community production were found to be very dependent on the method used. The method described by Brey (1990) was found acceptable for estimating secondary production in Arhus Bay but care should be exercised when comparisons are made with other areas where different methods have been used to estimate production. Secondary production was estimated more accurately for some of the abundant species in Arhus Bay on the basis of monthly samplings by the method described by Crisp (1984). Among the multivariate analyses the Detrended Correspondence Analysis (DCA) and nonmetric Multidimensional Scaling (MDS) proved to be the most successful with the Arhus Bay and Fornes data sets. Two Way INdicator SPecies ANalysis (TWINSPAN) did not work well with the Fornes data because it imposed discontinuities on data sets with continous variation in distribution of species among samples. As community types existed to a certain degree in Arhus Bay TWINSPAN worked well with these data. DCA and MDS were found to be useful techniques for analysing large data sets because they can summarize the data matrices to a manageable form and find possible patterns in the data sets. The results of the analyses can then be used as starting point for more detailed investigations of single species/samples or groups of species/samples. By using different transformations of the raw data the role of dominant or rare species can be assessed. A major 'problem in the assessment of multivariate techniques is the lack of external standards to compare with. The results of multivariate analyses must therefore be assessed critically on the basis of a careful examination of the species list combined with the knowledge and experience of the investigator. The methods used all had their advantages and limitations but each of the different methods added some important information to the picture of the benthic community in Arhus Bay and Fornes. It was thus an considerable advantage to use several different methods to analyse the spatial and temporal variability in the benthic fauna in relation to antropogenic and natural causes.

Macroinvertebrate assemblages were semi-quantitatively sampled from the Little Blue River and an isolated headwater stream in Wilbur Wright Fish and Wildlife Area from March through November of 2000. Physicochemical conditions and qualitative habitat characteristics were recorded at each site. Each stream contained unique community assemblages based on taxa richness, composition, functional feeding groups, behavioral groups, reproductive habits, and drought tolerance/avoidance. Collections from the first-order stream contained fewer taxa and a greater proportion of non-insects and tolerant taxa than those from the Little Blue River. Taxa from the Little Blue River were adapted for filtering/collecting and for swimming or clinging, while taxa from the first-order stream were primarily gathering/collecting and swimming or sprawling. The proportion of taxa with adaptations for drought resistance or avoidance was significantly higher in the first-order stream than in the Little Blue River (p<0.001). / Department of Biology

Communities in the vicinity of the Mico River, located in Chontales, Nicaragua, suffer from periodic dry season water shortages. The Mico River is impacted by artisanal and industrial mining, cattle ranching, effluent from local dairies and tanneries, and poor waste management practices in the watershed. Available water quality data consists of short term assessment studies and monitoring data for a mine operating in the headwaters, but to date this information has not been collated and interpreted as a whole. Communities in the vicinity of the Mico River have expressed an interest in having this data reviewed to verify information they have received from government and industry with regards to impacts from the La Libertad Mine. A gap analysis of existing water quality data in the headwaters of the Mico River is presented, with interpretation of current data and identification of further data needs. Recommendations are provided for future water quality monitoring in the region. The study area was defined as the Mico River watershed upstream of the town of Santo Tomas. A total of 14 studies were identified with information about the Mico River in this area. Individual study reliability was assessed, and study data were compiled to assess conditions in comparison to water quality guidelines and any spatial or temporal trends. Both water chemistry and bioassessment studies were assessed. The major gaps in existing information are: insufficient baseline/ reference information, insufficient information on impacts from contaminants other than metals, insufficient coverage of streams not directly impacted by the La Libertad Mine, poor quality and reliability of data, and poor coordination/ continuity between studies done to date. Cyanide concentrations were found to be below drinking water criteria at the majority of sample locations. Metals concentrations were elevated throughout the study area but it cannot be determined if this is due to natural background levels or anthropogenic sources. Water quality conditions with regards to other parameters (e.g., dissolved oxygen, temperature, pesticides and bacteria) and bioassessment data cannot be assessed due insufficient data quality and quantity. Existing monitoring in the region should be expanded to include reference locations. It is recommended that a benthic invertebrate bioassessment program designed for tropical mountain streams be implemented to supplement existing monitoring and identify areas where stream function is impaired, as bioassessment is cheaper and requires less equipment and logistical coordination than water chemistry monitoring programs. Whatever future work is done, care must be taken that study design and implementation is of a higher quality than that done to date, so that results are comparable and reliable. Coordination and cooperation between bodies involved in monitoring is essential for efficient use of scarce resources. / Graduate

Epithelia form protective barriers and regulate molecule transport between the mesenchyme and environment. Amongst all metazoans, only sponges are said to lack 'true' epithelia however the physiology of sponge cell layers are rarely studied empirically. Aggregates and gemmules of a freshwater demosponge, Spongilla lacustris, were used to grow confluent tissue over permeable culture wells which are required for transepithelial recordings. The transepithelial potential (TEP) of S. lacustris was slightly negative (-3mV), indicating possible control of ion transport. Transepithelial resistance (TER) was recorded between 1-2 k cm2, the same order of magnitude as many vertebrate epithelia. Cultures with high resistance blocked the passage of the small tracer molecules 14C-PEG, 3H-Inulin and ruthenium red. Pinacocytes were spatially stable over time and epithelial layers were morphologically similar in freshwater and marine species. These results suggest that sponge cell layers are able to control solute and ion transport, the physiological attributes of functional epithelia. / Physiology, Cell and Development Biology

Spatial heterogeneity of the environment, as measured by floral diversity, composition and structure, is known to influence the distribution and diversity of invertebrates. Heterogeneity brought about by anthropogenic disturbance may be a threat to invertebrate diversity. This thesis investigates the impacts of vegetation heterogeneity at a range of scales on the diversity of invertebrate populations in modified high-altitude indigenous grasslands on the Rock and Pillar Range, Central Otago. Invertebrates were sampled in and on the edges of snow tussock fragments to assess whether species richness increased systematically with fragment area. Invertebrate composition was poorly related to fragment area, plant composition and environmental variables. Taxon richness, abundance and/or diversity for three invertebrate groups increased as fragment area decreased, perhaps reflecting an influx of species from the surrounding matrix. For snow tussock leaf invertebrates in autumn, richness and abundance were at least two times lower in tussocks exposed to the wind than those in the centre of fragments, suggesting selection of habitat may be based on microclimatic characteristics. Invertebrates were sampled from the bases of tussocks after they were clipped to simulate three levels of vertebrate grazing. Invertebrate community composition differed between sites and sampling dates but was unaffected by clipping treatment. At the higher altitude site invertebrate abundance was 1.45 times greater and Shannon-Wiener diversity (H�) 1.22 times lower than at the lower altitude site. The latter sampling date had higher abundance (2.12 times) and taxon richness (1.14 times) than the earlier date. Pitfall-trapped invertebrates in cushionfield, herbfield and snow tussock differed in community composition and often by taxon richness, abundance and diversity. Across habitats, plant composition, plant diversity and some environmental variables were correlated with invertebrate variables, but could not be separated from vegetation type. The invertebrates collected in the course of the study are listed. Four Phyla, eight Classes, 24 orders and over 300 taxa were recorded. Almost all taxa are endemic and many have limited distributions and/or are undescribed. A species list is provided with collection altitude, method and habitat type. Invertebrate assemblages from sites differing in altitude, vegetation type and level of habitat modification on the Rock and Pillar Range are compared. Sites differed in species composition and rank orders of abundance and richness. At lower elevations, invertebrate richness was at least 25% less, and standardised trap abundance at least 44% less, than that at the highest elevation. Richness and abundance of exotic invertebrates decreased with increasing altitude. This thesis highlights several points concerning the study of grassland invertebrates and heterogeneity on the Rock and Pillar Range. First, there are differences in invertebrate assemblages at a range of scales. Conserving invertebrate diversity will therefore require altitudinal sequences and different habitat types, including disturbed areas. At high elevations, tussock habitat may be disproportionately important due to its relative rarity. Second, the effects of disturbance on invertebrates were only visible at large spatial scales. Third, there is a paucity of research on New Zealand invertebrates, especially in regard to terrestrial disturbance, which has resulted in a shortfall of biological, distributional, taxonomic and ecological knowledge.

Thesis (Ph.D.) - University of St Andrews, April 2006.

Made available in DSpace on 2014-12-17T14:03:25Z (GMT). No. of bitstreams: 1 RoberioMN.pdf: 839058 bytes, checksum: 1087756ecda3734e7aef07c3e72cb26c (MD5) Previous issue date: 2008-02-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / ?-D-glucosidase (EC 3.2.1.21) is one of the most interesting glycosidases, especially for hydrolysis cellobiose releasing glucose, is last step degradation of cellulose. This function makes the ?-D-glucosidase is of great interest as a versatile industrial biocatalyst, being critical to various bio-treatment / biorefinery processes, such as bioethanol production. Hen in the report, a ?-D-glucosidase was extracts from protein extracted of the invertebrate marine Artemia franciscana was purified and characterized with a combination of precipitation with ammonium sulfate (0 - 30%, 30 to 50%, 50 to 80%), the fraction saturated in the range of 30 to 50% (called F-II) was applied in a molecular exclusion chromatography, in Sephacryl S-200, the fractions corresponding to the first peak of activity of ?-D-glucosidase were gathered and applied in a chromatography of ion exchange in Mono Q; the third peak this protein obtained chromatography, which coincides with the peak of activity of ?-D-glucosidase was held and applied in a gel filtration chromatography Superose 12 where the first peak protein, which has activity of ?-D-glucosidase was rechromatography on Superose 12. This enzyme is probably multimerica, consisting of three subunit molecular mass of 52.7 kDa (determined by SDS-PAGE) with native molecular mass of 157 kDa (determined by gel filtration chromatography on Superose 12 under the system FPLC). The enzyme was purified 44.09 times with a recovery of 1.01%. Using up p-nitrophenyl-?-D-glucopiranoside as substrate obtained a Km apparent of 0.229 mM and a Vmax of 1.109 mM.60min-1.mL-1mM. The optimum pH and optimum temperature of catalysis of the synthetic substrate were 5.0 and 45 ?C, respectively. The activity of the ?-D-glucosidase was strongly, inhibited by silver nitrate and N- etylmaleimide, this inhibition indicates the involvement of radical sulfidrila the hydrolysis of synthetic substrate. The ?-D-glucosidase of Artemia franciscana presented degradativa action on celobiose, lactose and on the synthetic substrate ?-nitrophenyl-?-D-glucopiranoside indicating potential use of this enzyme in the industry mainly for the production of bioethanol (production of alcohol from the participating cellulose), and production hydrolysate milk (devoid of milk lactose) / ?-D-glicosidase (EC 3.2.1.21) ? uma das mais interessantes glicosidases, especialmente por hidrolisar celobiose liberando glicose, ?ltimo passo de degrada??o de celulose. Esta fun??o faz com que a ?-D-glicosidase seja de grande interesse como um vers?til biocatalizador industrial, sendo critica para v?rios processos de bio-tratamento / biorrefinaria, como produ??o de bioetanol. Neste trabalho, uma ?-D-glicosidase extra?da de extratos prot?icos do invertebrado marinho Artemia franciscana foi purificada e caracterizada com uma combina??o de precipita??o com sulfato de am?nio (30; 50; 80%), a fra??o saturada na faixa de 50% (chamada F-II) foi aplicada em uma cromatografia de exclus?o molecular em Sephacryl S-200, as fra??es correspondentes ao primeiro pico de atividade da ?-D-glicosidase foram reunidas e aplicadas numa cromatografia de troca i?nica em Mono Q; o terceiro pico prot?ico obtido nessa cromatografia, o qual coincide com o pico de atividade da ?-D-glicosidase, foi reunido e aplicado numa cromatografia gel filtra??o Superose 12 onde o primeiro pico prot?ico, o qual possui atividade da ?-D-glicosidase, foi recromatografado em Superose 12. Esta enzima provavelmente ? multimerica, constitu?da por tr?s subunidades, de massa molecular de 52,7 kDa (determinado por SDS-PAGE) e com massa molecular nativa de 157 kDa (determinado por cromatografia gel filtra??o em Superose 12 sob o sistema FPLC). A enzima foi purificada 44,09 vezes com uma recupera??o de 1,01%. Utilizando-se ?-nitrofenil-?-D-glicopiranos?deo como substrato obtivemos uma Km aparente de 0,229 mM (12,7 ?M de produto/cm/hora) e Vm?x de 1,109 mM.60min-1.mL-1. O pH ?timo e a temperatura ?tima de cat?lise do substrato sint?tico foram 5,0 e 45?C, respectivamente. A atividade ?-D-glicosid?sica foi fortemente inibida por nitrato de prata e N-etilmaleimida, esta inibi??o indica o envolvimento de radicais sulfidrila na hidr?lise do substrato sint?tico. A ?-D-glicosidase de Artemia franciscana apresentou a??o degradativa sobre celobiose, lactose e sobre o substrato sint?tico ?-nitrofenil-?-D-glicopiranos?deo, indicando potencial uso desta enzima na ind?stria principalmente para produ??o de bioetanol (produ??o de ?lcool a parti de celulose) e produ??o de leite hidrolisado (leite destitu?do de lactose)

Ferreira, M., Dr.; Van Vuren, J.H.J., Prof. / The Wilge River is one of many adjoining tributaries of the Olifants River located in the Olifants Water Management Area (WMA4) within the Highveld (11) – Lower Level 1 Ecoregion (Dallas, 2007). These river systems experience extreme demand for natural resources, as they flow through heavily utilised economic hubs. They are closely associated with land modification and pollution, primarily mining and industrial-related disturbances and extensive agricultural activities, all of which are the primary cause of impairment to river health. The primary aim of this study was to study the aquatic macroinvertebrate communities at six monitoring sites along the Wilge River, coupled with two monitoring sites on adjoining tributaries, and to further identify the driving variables that influence these communities both spatially and temporally. Functional Feeding Groups (FFGs) of the aquatic macroinvertebrates and the surrounding land use in the project area was taken into account. The analysis of in situ water quality measured during the period March 2010 to May 2013, clearly illustrated high levels of variation both spatially and temporally. In situ water quality was a limiting factor to the aquatic ecosystem from a Dissolved Oxygen (DO) and Percentage Saturation (DO%) perspective. The remaining parameters were within the South African guideline for aquatic ecosystems (DWAF, 1996). Habitat availability illustrated clear seasonal variation as well, of which the wet season indicated better habitat availability compared to the dry season. The dominant biotopes in the study area were vegetation (VEG) and gravel, sand and mud (GSM). Site WIL04 illustrated the poorest habitat integrity overall primarily attributed to the site’s steep incised banks and deep channel which lacks the stones biotope. The South African Scoring System, Version 5 (SASS5) results indicated that there was a change in the integrity of the aquatic macroinvertebrate community’s in the study area and further illustrated variability both spatially and temporally. It was evident that the aquatic macroinvertebrate communities within the Wilge River and two adjoining tributaries sampled, were generally in a slightly to modified state with moderate variations. The lowest number of taxa, SASS5 and average score per taxon (ASPT) values was recorded at site WIL04 and this was mainly brought about due to changes in flow and habitat availability. The ASPT score ranged from 3.8 at site WIL04 to 7.7 at site WIL02, indicating that the aquatic macroinvertebrate communities were primarily composed of tolerant and moderately tolerant taxa. Of these mostly tolerant taxa, predators and gathering collector populations were the most dominant FFG, with the shredders being the least abundant within the study area. The Bray-Curtis cluster analysis of the aquatic macroinvertebrate communities clearly illustrated a high level of similarity and seasonal variation among the communities. The high similarity was an indication that similar taxa occurred at the sites within the groups identified. However, in accordance with the Similarity Percentages (SIMPER) analysis, there was no clear indication of dominant taxa. There was however a separation of sites TRI01 and WIL04. This was expected due to differences in the physical stream condition (flow) and other habitats / general biotopes, primarily at site WIL04. Stream bed composition is one of the most important physical factors controlling the structure of freshwater invertebrate communities (Mackay and Eastburn, 1990). The separation and similarity of these two sites were not a consequence of dominant taxa, but rather a consequence of differing water quality, habitat availability and common tolerant taxa driving the system. Inclusive, the seasonal variation illustrated was contributing to the changes in the in situ water quality and habitat availability, thus making seasonal variation also a driving variable, in the differences between the sites. The Redundancy Analysis (RDA) bi-plots indicated, as with the Bray-Curtis similarity matrices and related NMDS plot, that there was a distinct seasonal separation. It further illustrated a clear separation of site TRI01 and WIL04 due to reasons mentioned above. All the environmental variables, with the exception of pH, was identified as significant drivers in the river systems (p<0.05). This however varied seasonally. During the wet season, clarity, DO and pH were the significant drivers, while clarity, TDS/EC, percentage saturation and pH were the significant drivers during the dry season (p<0.05). These drivers were expected due to possible sources namely intensive agriculture in the project area. The RDA tri-plots further indicated the significant role that the ASPT, SASS5 score and the IHAS played within the aquatic macroinvertebrate community (p<0.05). This confirms the importance of habitat as a driving variable in aquatic macroinvertebrate community structures. Consequently, the driving variables in the separation of the sites along the Wilge River and two adjoining tributaries, appear to be a combination of variables (DO, percentage saturation, TDS/EC, clarity and pH), including habitat availability (based on IHAS scores). To determine the effects and relations between the primary driving changes, to the surrounding land uses in the project area, further multivariate analyses were conducted, which included the FFGs. It was clearly indicated that predators have a negative correlation with the rest of the FFG’s which was expected. As the percentage of predators increase at a site, the percentage of the other FFG’s decreased. Therefore, there was a large variation and clear changes in the food sources constantly entering into the river system. This is normally related to changes in the land use.