Filtration of the Microalga Amphidinium carterae by the Polychaetes Sabella spallanzanii and Branchiomma luctuosum: A New Tool for the Control of Harmful Algal Blooms?

Harmful algal blooms (HABs) are extreme biological events representing a major issue in marine, brackish, and freshwater systems worldwide. Their proliferation is certainly a problem from both ecological and socioeconomic contexts, as harmful algae can affect human health and activities, the marine ecosystem functioning, and the economy of coastal areas. Once HABs establish, valuable and environmentally friendly control actions are needed to reduce their negative impacts. In this study, the influence exerted by the filter-feeding activity of the two sabellid polychaetes Branchiomma luctuosum (Grube) and Sabella spallanzanii (Gmelin) on a harmful dinoflagellate was investigated. Clearance rates (C) and retention efficiencies were estimated by employing the microalga Amphidinium carterae Hulburt. The Cmax was 1.15 ± 0.204 L h−1 g−1 DW for B. luctuosum and 0.936 ± 0.151 L h−1 g−1 DW for S. spallanzanii. The retention efficiency was 72% for B. luctuosum and 68% for S. spallanzanii. Maximum retention was recorded after 30 min for both species. The obtained results contribute to the knowledge of the two polychaetes’ filtration activity and to characterize the filtration process on harmful microalgae in light of the protection of water resources and human health. Both species, indeed, were extremely efficient in removing A. carterae from seawater, thus suggesting their employment as a new tool in mitigation technologies for the control of harmful algae in marine environments, as well as in the aquaculture facilities where HABs are one of the most critical threats.

Manufacturing and assessing new samplers to measure wind soil erosion

Wind soil erosion is one of the most important causes of soil degradation that impede the process of sustainable agricultural development. The first step to mitigating wind erosion hazards is to find an effective and accurate way to assess its severity. Therefore, the main objective of this research was to raise and evaluate the efficiency of the new four traps to measure eroded soil, Fixed Distance trap (FD), Fixed Point trap (FP), Rotary Distance trap (RD) and Rotary Point trap (RP). The study traps RP and FP compared with the Big Spring Number Eight trap (BSNE) (traditional trap) and the traps RD and FD compared with the Bagnold trap (traditional trap). The results indicated that the order of study traps in terms of soil collection efficiency and soil retention efficiency were RD>FD>Bagnold>RP>FP>BSNE and FP>RP>RD>FD>Bagnold>BSNE, respectively. Results proved that the best traps in collecting eroded soil were RP trap followed by FP trap, compared to BSNE trap. Also, the best traps in collecting eroded soil were RD trap, followed by FD trap, compared to the Bagnold trap. The most important results showed that the relative efficiency of RP and FP traps were 181% and 159%, respectively, compared to BSNE and the relative efficiency of RD and FD traps were 186% and 172%, respectively, compared to the Bagnold trap. The study proved high accuracy of new traps in measuring soil eroded material, separating soil particles according to their size directly inside traps and determining the direction of the wind compared to traditional traps.

Mechanical treatment of wastewater

Подбор оборудования для механической очистки сточных вод является важным этапом при реконструкции или новом строительстве очистных сооружений, который определяет их эффективность и надежность с точки зрения технологии и эксплуатации. Приведены примеры распространенных на данный момент технических решений по конструкции фильтрующего полотна решеток для механической очистки сточных вод. Дано сравнение эффективности данных решений. На основе исследования очистных сооружений в Германии представлено сравнение эффективности задержания отбросов в зависимости от применяемого ранга фильтрации: двумерной (перфорация) и одномерной (прозор). The selection of equipment for mechanical wastewater treatment is an important stage in the reconstruction or new construction of the treatment facilities that determines their efficiency and reliability in terms of the technology and operation. The examples of the currently widespread technical solutions for designing filtering cloth of the screens for mechanical wastewater treatment are given. The effectiveness of these solutions is compared. On the basis of studying wastewater treatment facilities in Germany, a comparison of the debris retention efficiency depending on the applied filtration grade, i. e., two-dimensional (perforation) and one-dimensional (bar spacing) is presented.

SEPARATION OF HEMICELLULOSES FROM AN INDUSTRIAL STREAM BY NANOFILTRATION AND ULTRAFILTRATION PROCESSES

The performance of nanofiltration (NF) and ultrafiltration (UF) membranes was studied for separating hemicelluloses from a highly alkaline industrial stream, containing 17-18 wt% sodium hydroxide, resulting from the viscose process. Initially, screening experiments were performed to select suitable membranes, which were then investigated on a pilot scale spiral module. Screening experiments showed that the UF membrane, with a nominal molecular weight cut-off (MWCO) value of 3 kDa, and the NF one, with a nominal MWCO value of 0.5 kDa, showed a similar range of filtration performance and a flux of 4.2 L/m2.h. Further, a retention efficiency of 50% was observed for the 5 kDa and the 10 kDa membranes, indicating absence of any significant proportion of hemicelluloses in this range of molecular weights. The effects of process conditions were studied to understand their correlation with membrane performance with respect to hemicelluloses retention and permeate flux. UF membranes were found to be more prone to performance deterioration over time and with the number of cycles of usage during the pilot scale study, whereas the NF membrane showed consistent performance. It was seen that feed dilution can improve the membrane performance with respect to sodium hydroxide recovery. Significant reduction in feed viscosity with dilution resulted in a 50% increase in flux after normalizing for concentration.

Effect of Type and Dietary Fat Content on Rabbit Growing Performance and Nutrient Retention from 34 to 63 Days Old

The study was carried out on individually and collectively housed growing rabbits from 34 to 63 days of age. Two experiments were conducted using three fat sources: Soybean oil (SBO), Soya Lecithin Oil (SLO), and Lard (L; Exp. 1), and SBO, Fish Oil (FO), and Palm kernel Oil (PKO; Exp. 2), added at two inclusion levels (1.5 and 4.0%). In both trials, 180 rabbits were housed in individual cages and additional 600 rabbits in collective cages from day 34 to 63. Animals fed with 4% dietary fat showed lower Daily Feed Intake (DFI) and Feed Conversion Ratio (FCR) than those fed with 1.5%, except in the individually housed animals in Exp. 1. In the collective housed group in Exp. 1, DFI was a 4.8% higher in animals fed with diets containing lard than those fed with SBO (p = 0.036). Lard inclusion also tended to reduce mortality (p = 0.067) by 60% and 25% compared with SBO and SLO diets, respectively. Mortality was the highest with the higher level of soya lecithin (14% vs. 1%, p < 0.01). A similar mortality rate was observed in the lowest level of SBO. In the grouped-housed animals in Exp. 2, a decrease of DFI (−12.4%), Bodyweight (BW) at 63 d (−4.8%), and Daily Weight Gain (DWG) (−7.8%) were observed with the inclusion of fish oil (p < 0.01) compared to other fat sources. Fish oil also tended to increase (p = 0.078) mortality (13.2%) compared with palm kernel oil (6.45%); similar results were found when animals were individually housed. The overall efficiency of N retention (NRE) increased with the highest level of fat in Exp. 1 (34.9 vs. 37.8%; p < 0.0001). It can be concluded that lard and palm kernel oil are alternative sources of fat due to the reduction of mortality. The inclusion of fish oil impaired animal productivity and increased mortality. An increment of the dietary fat level improved FCR and overall protein retention efficiency.

Measuring the Effects of Microplastics on Sponges

<p>Microplastics (MP’s) are ubiquitous throughout the marine environment, and are derived from either direct production or from the fragmentation (to <5mm) of larger plastic pollution. Recently concern has intensified as the extent of MP pollution and its presence in the marine environment has been highlighted. Literature concerning concentrations of microplastics indicates an increasing occurrence in the marine environment, from coastal beaches to deep sea sediments. In addition, the effects microplastics have on marine organisms are well documented, with studies ranging from large pelagic animals to benthic filter feeders. However to date, there are few data on how MPs influence Porifera. Sponges are an important component of temperate benthic ecosystems, providing a range of important functional roles. Sponges are able to adapt to many environments by exploiting a variety of food sources, from dissolved organic matter to small crustaceans. Regardless of this, sponges feed primarily on picoplankton, and are able to retain up to 99% of these from seawater. The impact microplastics have on these suspension feeders is becoming of increasing concern, and previous research has centred primarily on sponge feeding or responses to sediments. As such, this thesis is the first to focus on the metabolic responses of sponges to MPs. To examine this, two response variables were measured: O₂ consumption (Respiration) and feeding (Retention efficiency). To examine the effects of MP on sponge respiration, two temperate sponge species (Tethya bergquistae and Crella incrustans) were exposed to two different sized plastic particles (1 μm and 6 μm) at two different concentrations (200,000 and 400,000 beads per mL). Results indicate that sponges are resilient to MP pollution. The only significant result was the effect of MP size on the respiration rates on Tethya bergquistae (P = 0.001), but there were no other significant main effects or interactions. Marine particulates come in many shapes and sizes, as such the retention abilities of temperate sponges were tested after exposure to different types and sizes of particulates. This was achieved by subjecting the same two sponge species (Crella incrustans and Tethya bergquistae) to two microplastic (1 μm & 6 μm), two sediment (1 μm & 6 μm) and two “Food” (raw sea water and Isochrysis galbana) treatments. This experiment showed some significant retention differences, but these differences were difficult to explain and largely inconclusive. This has highlighted the need for further investigation into the effects of: mixed treatments (i.e. sediments + plastics together) and varying plastic shapes (sphere + fibre + fragment). Finally, there is a crucial gap in knowledge regarding the fate of microplastics after ingestion by sponges. This research outlines the potential for temperate sponges to be resilient to microplastics particles when considering respiration rates. In addition, this study also outlines the variable nature of Crella incrustans and Tethya bergquistae concerning particulate retention. As the MP concentrations used in this thesis are very high and are unlikely to be found in New Zealand in the near future, this thesis therefore demonstrates the capability for sponges to be resilient to microplastic pollution. The outcomes of my thesis highlight the importance of understanding the impacts of microplastics on benthic organisms. The marine environment is dynamic and organisms are susceptible to a multitude of stressors. As such, there is a need to explore interactions between multiple factors at the same time.</p>

Measuring the Effects of Microplastics on Sponges

<p>Microplastics (MP’s) are ubiquitous throughout the marine environment, and are derived from either direct production or from the fragmentation (to <5mm) of larger plastic pollution. Recently concern has intensified as the extent of MP pollution and its presence in the marine environment has been highlighted. Literature concerning concentrations of microplastics indicates an increasing occurrence in the marine environment, from coastal beaches to deep sea sediments. In addition, the effects microplastics have on marine organisms are well documented, with studies ranging from large pelagic animals to benthic filter feeders. However to date, there are few data on how MPs influence Porifera. Sponges are an important component of temperate benthic ecosystems, providing a range of important functional roles. Sponges are able to adapt to many environments by exploiting a variety of food sources, from dissolved organic matter to small crustaceans. Regardless of this, sponges feed primarily on picoplankton, and are able to retain up to 99% of these from seawater. The impact microplastics have on these suspension feeders is becoming of increasing concern, and previous research has centred primarily on sponge feeding or responses to sediments. As such, this thesis is the first to focus on the metabolic responses of sponges to MPs. To examine this, two response variables were measured: O₂ consumption (Respiration) and feeding (Retention efficiency). To examine the effects of MP on sponge respiration, two temperate sponge species (Tethya bergquistae and Crella incrustans) were exposed to two different sized plastic particles (1 μm and 6 μm) at two different concentrations (200,000 and 400,000 beads per mL). Results indicate that sponges are resilient to MP pollution. The only significant result was the effect of MP size on the respiration rates on Tethya bergquistae (P = 0.001), but there were no other significant main effects or interactions. Marine particulates come in many shapes and sizes, as such the retention abilities of temperate sponges were tested after exposure to different types and sizes of particulates. This was achieved by subjecting the same two sponge species (Crella incrustans and Tethya bergquistae) to two microplastic (1 μm & 6 μm), two sediment (1 μm & 6 μm) and two “Food” (raw sea water and Isochrysis galbana) treatments. This experiment showed some significant retention differences, but these differences were difficult to explain and largely inconclusive. This has highlighted the need for further investigation into the effects of: mixed treatments (i.e. sediments + plastics together) and varying plastic shapes (sphere + fibre + fragment). Finally, there is a crucial gap in knowledge regarding the fate of microplastics after ingestion by sponges. This research outlines the potential for temperate sponges to be resilient to microplastics particles when considering respiration rates. In addition, this study also outlines the variable nature of Crella incrustans and Tethya bergquistae concerning particulate retention. As the MP concentrations used in this thesis are very high and are unlikely to be found in New Zealand in the near future, this thesis therefore demonstrates the capability for sponges to be resilient to microplastic pollution. The outcomes of my thesis highlight the importance of understanding the impacts of microplastics on benthic organisms. The marine environment is dynamic and organisms are susceptible to a multitude of stressors. As such, there is a need to explore interactions between multiple factors at the same time.</p>

Influence of Simplified Microbial Community Biofilms on Bacterial Retention in Porous Media under Conditions of Stormwater Biofiltration

The retention efficiency of bacterial contaminants in biofilm-colonized biofilters is highly variable. Despite the increasing number of studies on the impact of biofilms in filters on bacterial retention, how individual bacterial strains within a biofilm community combine to influence bacterial retention is unknown.

Particle Retention Capacity, Efficiency, and Mechanism of Selected Plant Species: Implications for Urban Planting for Improving Urban Air Quality

Atmospheric particulate matter (PM) has been of concern owing to its negative effects on human health and its role in environmental degradation. For mitigation purposes, it is important to select the most efficient plant species in urban greening. Here, a fast, cost-saving methodology was first added to the conventional method to investigate the size-resolved PM retention capacity and efficiency of twenty plant species. Surface PM (SPM), which can be removed by water and brushing, accounted for 44.9%−66.9% of total PM, in which the water-soluble PM (DPM) accounted for 12.9%−22.1% of total PM. A large mass proportion of in-wax PM (14.1%−31.7%) was also observed. Platycladus orientalis, Eriobotrya japonica, Viburnum odoratissimum, Magnolia grandiflora had the highest AEleaf (retention efficiency on per unit leaf area) to retain SPM within different diameter classes (DPM, PM0.1-2.5, PM2.5-10, PM>10). AEplant (retention efficiency of individual tree) varied greatly among different plant species, mainly due to the dependence on the total area of a tree. AEland (retention efficiency on per unit green area) is a suitable index for PM retention ability and efficiency. In general, P. orientalis, V. odoratissimum, Pittosporum tobira, Photinia serrulate, M. grandiflora, E. japonica were the efficient species in retaining PM at different scales (i.e., leaf, individual tree, green area). The species like Trifolium repens, Phyllostachys viridis, were the least efficient plant species. The investigated species are all evergreen species, which will remove PM throughout the whole year, even in winter. So, we recommended that the plant species with the highest PM retention efficiency can be used in urban greening. Meanwhile, horticulture practices should also be considered to improve the leaf area index to improve their PM retention and air purification abilities.