Water quality characteristics of the heavily urbanised and industrialised Swartkops River catchment in the Eastern Cape has been the focus of several studies since the 1970s. Overloaded and poorly maintained wastewater treatment works (WWTW), polluted stormwater runoff and solid waste have had a negative impact on the water quality status of the Swartkops River and estuary. Past studies have revealed that a distinct relationship exists between land use activities and the water quality of the Swartkops Estuary, which in turn has raised concerns pertaining to the ecological, economic, recreational, and cultural value of the estuaryThe Swartkops Estuary has a Present Ecological State (PES) of Category D(1) and a Recommended Ecological Category (REC)(2) of a C (Van Niekerk et al., 2014). It is known that effective management of anthropogenic impacts on coastal systems requires a thorough understanding of the system’s biological responses to wastewater discharges and to hydrologic changes. For this reason, the objective of this study was to determine the current water quality status of the Swartkops Estuary, and to gain greater insight into factors controlling eutrophication. This was important as outdated water quality information was used in the Swartkops Integrated Environmental Management Plan (Enviro-Fish Africa, 2011) due to a lack of current data. To determine the current water quality status of the Swartkops Estuary the present study investigated spatial and temporal variability in physico-chemical parameters, nutrients, phytoplankton biomass and community composition, faecal bacteria, and “where possible” related this to historical water quality data. In general, points of entry into the estuary were investigated for their impact on nutrient enrichment and the bacteriological status of the estuary. Water quality surveys were completed in September 2012, November 2012, February 2013, May 2013 and August 2013The present study found evidence to suggest that water is not flushed as efficiently from the estuary as was previously the case, and that the natural hydrology of the estuary has been modified. These changes appear to be the effect of large volumes of wastewater discharges from the wastewater treatment works (WWTW), which has led to the additional stresses of increased vertical stratification and reduced vertical mixing. A build-up of dissolved inorganic nutrients has given rise to persistent eutrophic conditions and phytoplankton blooms occurring from the middle reaches to the tidal limit of the estuary. These findings were associated with a generally well oxygenated estuary; however, bottom water hypoxic conditions were recorded in the upper reaches of the estuary on two occasions and were generally associated with bloom.forming flagellates. Elevated concentrations of inorganic nutrients stimulated phytoplankton to attain high biomass ranging from 0 to 248 g l-1 (31.8 6.56 g l-1). All nutrients displayed positive linear gradients from the mouth to the tidal limit, showed significant (p < 0.05) temporal and spatial variability, and were significantly (p < 0.05) correlated with phytoplankton biomass. Phytoplankton blooms (> 10 000 cells ml-1) of several different groups were recorded from the middle reaches of the estuary to the tidal limit. Diatoms were the dominant group during increased freshwater inflow (at mean daily flow rate of 2.14 m3 s-1) and low DIP levels, whereas flagellates were generally the dominant group during reduced flow and under higher nutrient levels. Although the different tidal stages had no effect on phytoplankton biomass per se, it did support co-existance between phytoplankton groups. This was noted during the spring ebb tide in September 2012 (i.e. flagellates, diatoms and dinoflagellate) and in February 2013 (i.e. dinoflagellates, diatoms and chlorophytes). Phytoplankton blooms have become persistent in the middle to upper reaches of the estuary where chlorophyll-a was > 20 µg l-1 and cell density exceeded 10 000 cells ml-1; a situation not reported in previous studies. The Motherwell Canal was and still is the main source of nitrogen (generally in the form of ammonium) to the estuary, whereas the Swartkops River is still the primary source of phosphorus to the estuary. Since the stormwater canal services the large residential area of Motherwell where leaks in the sewer system, the dumping of night soil buckets, and faulty pumps are often reported, polluted discharges from the Motherwell Canal can enter the canal at any given point. In contrast to the canal, DIP loading from the Swartkops River to the estuary generally occurred under conditions of low flow, whereas nitrogen showed no apparent relationship. Faecal bacteria originating from the Motherwell Canal had the most profound effect on the bacteriological status in the middle reaches of the estuary, whereas the Swartkops River had an intermediate effect due to bacteria die-offs occurring between the point of release from the WWTW to the riverine reaches and the tidal limit of the estuary. Nevertheless, Escherichia coli and enterococci levels are still high, especially in the summer months rendering the estuary unsafe for recreation during this season. Historical data on trace metals in the water column were limited and thus observations from the present study could not be concluded with much confidence. However, preliminary data suggest that levels of copper, zinc, iron and cadmium have increased by at least 90% in the estuary, at the tidal limit of the estuary and in the Markman and Motherwell canals. High inputs of nutrients, trace metals and faecal bacteria to the estuary from land-use activities indicate the necessity for remedial actions with the main objective being to conserve and protect the estuary’s recreational, ecological and economic functions.

Threespine stickleback (Gasterosteus aculeatus) and juvenile chinook salmon (Oncorhynchus tshazvytscha) co-occur during high tide in tidal channels of the Fraser River estuary. Given the high density of resident stickleback, there is the potential for strong interactions within and between the two species. Inter- and intra-specific interactions were tested by means of laboratory experiments, with support from field studies. Laboratory experiments placed stickleback and chinook in mixed and single species groups. The levels of aggressiveness were quantified, along with prey choice between surface (Drosophila), midwater (Artemia), and benthic (Tubifex) prey; microdistribution was also recorded. The experiments demonstrated that stickleback were highly aggressive towards chinook, and would drive them away from optimal feeding territories. Chinook consumed surface prey only when tested with stickleback, exploiting benthic and midwater prey when feeding alone. Stickleback demonstrated no significant difference in diet between single and mixed species trials, which is consistent with the supposition of strongly asymmetrical competition for food and space. Field data lend further support to this premise; a marked difference observed in diet suggests microhabitat partitioning between the two species, with stickleback feeding on benthos and chinook largely consuming surface prey. This thesis proposes that interactive segregation is an important process between sympatric stickleback and juvenile chinook in estuarine tidal channels and might have important implications for Fraser chinook stocks. / Science, Faculty of / Zoology, Department of / Graduate

Objetivando contribuir para futuros programas e projetos de planejamento ambiental na região de Cananéia-Iguape e Ilha Comprida, foram realizados no presente estudo levantamentos de dados dos meios social, econômico e ambiental, que visaram demonstrar o atual estado desta região, de forma que pudessem ser identificados os principais aspectos de vulnerabilidade socioambiental. Para subsidiar a análise, foi aplicado o modelo conceitual DPSIR (Forças Motoras- Pressão- Estado- Impacto- Resposta), cujo resultado demonstrou que a região apesar de concentrar diversas Unidades de Conservação, apresenta sinais de interferência humana evidentes na qualidade da água do estuário, apresentando em determinadas localidades do estuário problemas de eutrofização. Além deste problema, foi identificado na área de estudo, a necessidade de maiores investimentos para o desenvolvimento socioecômico local. O uso do modelo DPSIR colaborou de forma adequada para apontar problemas além dos anteriormente citados, demonstrando dessa forma, como uma excelente ferramenta para apoio de futuros projetos de planejamento ambiental na região. / Aiming to contribute for future programs and environmental planning projects in the Cananéia-Iguape and Ilha Comprida region, was made in this paper a data-collection using social, economic and environmental factors that had demonstrated the current situation of the main aspects of the region and its social-environmental vulnerability. To subsidize the analysis a conceptual model DPSIR was applied (Drivers - Pressure - State _ Impact - Response), and its result demonstrated that the region although the concentration of diverse protected areas presents signals of interference human evidences in the water quality of the estuary, such as eutrophication processes. Beyond this problem, the necessity of investments for the local development was identified in the region. The use of the DPSIR model collaborated to point problems beyond previously cited, demonstrating it as an excellent tool to support future projects of environmental planning in the region.

The purposes of this research were to determine the efficacy of using the Ogawa® passive sampling device (PSD) to measure ammonia and to identify significant ammonia sources adjacent to Hillsborough and Tampa Bay. Ninety-four samplers were deployed over a 180-km2 area for two weeks in October 2001. Within the area sampled were located suburbs, an urban center, major highways, port activities, fertilizer manufacturing, wastewater treatment, coal-combustion power plants, warehousing and dairy farming. The sampled locations were arranged in a triangular grid pattern spaced 1.5 km apart. The pattern was designed to locate circular hot spots with a minimum radius of 0.75 km. The minimum, maximum, mean, and median ammonia concentrations were 0.06, 15, 2.0, and 1.5 mg/m3, respectively, and the estimated precision was 16%. Hot spots identified from kriged concentration data coincided with inventoried ammonia sources. The relative bias and precision of the PSD based on collocation with an annular denuder system were (plus or minus) 30 % and 20 %.

The endemic eelgrass (Zostera marina) community of Morro Bay Estuary, located on the central coast of California, has experienced an estimated decline of 95% in occupied area (reduction of 344 acres to 20 acres) from 2008 to 2017 for reasons that are not yet definitively clear. One possible driver of degradation that has yet to be investigated is the role of herbicides from agricultural fields in the watershed that feeds into the estuary. Thus, the primary research goal of this project was to better understand temporal and spatial trends of herbicide use within the context of San Luis Obispo (SLO) County and Morro Bay Watershed by analyzing data of application by mass, area, and intensity to identify herbicides with the highest potential for local environmental pollution. California Pesticide Use Annual Summary Reports (PUASR) from the years 2000 to 2017 were used to obtain data for conducting a meta-analysis to estimate total herbicide application by weight within every township, range, and section for each of the eight selected herbicides: oxyfluorfen, glyphosate, diuron, chlorthal-dimethyl, simazine, napropamide, trifluralin, and oryzalin. A second goal was to select an analytical laboratory that would be best suited for herbicide analysis of estuary sediments to determine the presence, or lack thereof, of the eight selected herbicides. Criteria of consideration in laboratory selection included herbicides detection capabilities, detection/reporting limits, testing prices, chain of custody protocols, turnaround times, and laboratory site locations. The meta-analysis yielded results showing high herbicide application rates in SLO County with glyphosate, oxyfluorfen, and chlorthal-dimethyl being identified as three herbicides of elevated risk for local environmental contamination due high rates of use by mass, by area, and/or intensity during the study timeframe. Additionally, Morro Bay Watershed exhibited moderate rates of herbicide application with chlorthal-dimethyl and glyphosate being of highest risk for contamination and accumulation within the estuary because of high application rates by mass, by area, and/or intensity. Finally, Environmental Micro Analysis (EMA) and Primus Group, Inc. (PrimusLabs) were identified as the top candidates for analytical laboratory testing of Morro Bay Estuary sediment samples to be obtained and tested for the selected herbicides. These laboratories provide superior analytical capabilities of the eight herbicides, impressive reporting limits or lower detection limits, competitive testing prices for detecting multiple constituents in multiple samples, robust chain of custody protocols, options for quick turnaround times, and laboratory site locations within California.

There is a growing need to better understand the dynamics of small and medium Mediterranean low-inflow estuaries (LIEs), which is addressed here by characterizing a heat budget and associated heat transfer processes. A one-dimensional deterministic model was developed from the advection-diffusion equation and applied to Morro Bay, CA using 15-minute water property (temperature, salinity, pressure) and meteorological (wind speed and direction, air temperature, relative humidity, air pressure, irradiance) data collected over a two-year period (2020 – 2021). Seasonal variability is observed in meteorological components, water temperature, and salinity. There is strong seasonal variability in head-mouth temperature and salinity differences. Temperature differences peak in summer (daily mean 2.52 ºC, June – Sept.). Daily average salinity difference is 0.33 (hyposaline, Sept. – Apr.) with strongest gradients observed during the winter storm season following enhanced freshwater discharge. Inverse salinity develops intermittently May – Aug. Subtidal heat flux is dominated by surface heating, whose daily average is always positive (heat input). The developed model does not quantify adequate heat export from the estuary, however, a sensitivity analysis indicates that diffusive flux may be a significant heat export component. Excess heat appears to be exported to the ocean, allowing ocean-estuary temperatures to remain similar. Characterizing estuarine dynamics like these enables us to predict how Morro Bay, and other similar estuarine systems, may respond to long and short-term environmental changes, and how these responses influence estuarine circulation and environmental health.

The temporal variation of nematode communities in eight mouth stations of the Mekong River system was investigated in order to compare the change between the dry and the wet season. The nematode data was analysed by multivariate techniques such as SIMPROF, MDS, ANOSIM and SIMPER in the software PRIMER v.6 – PERMANOVA. Our results showed that average dissimi-larity between seasons of the nematode communities in each station was high. Seasonal factor did not affect strongly their distribution pattern. Dominant genera Desmodora and Oncholaimellus usually occurred in the sand stations and Parodontophora and Halalaimus were characteristic for the silty group in both seasons. The spatial variations in this estuarine area have an influence that is larger than seasonal factors. / Sự phân bố theo thời gian của quần xã tuyến trùng sống tự do vùng cửa sông Mekong được nghiên cứu nhằm đánh giá sự khác biệt của chúng trong mùa mưa và mùa khô. Dữ liệu của tuyến trùng được xử lý và phân tích đa biến như SIMPROF, MDS, ANOSIM và SIMPER bằng phần mềm PRIMER v.6 – PERMANOVA. Kết quả nghiên cứu cho thấy sự khác biệt theo mùa trong quần xã tuyến trùng tại mỗi điểm là khá lớn nhưng yếu tố mùa không ảnh hưởng gì tới mô hình phân bố của chúng. Một số giống ưu thế trong nền đáy cát như Desmodora and Oncholaimellus trong khi đó Parodontophora và Halalaimus thích nghi nền bùn sét phù sa vẫn hiễn diện trong cả 2 mùa. Kết quả nghiên cứu cũng cho thấy sự biến động trong không gian ở đây lớn hơn sự biến động về mùa vụ.

Estuaries are vital environmental and economic resources, providing habitat for thousands of species, absorbing runoff, and supporting recreation and commerce. Yet, despite their importance, estuaries are threatened by human activities. Empirical Orthogonal Function (EOF) analysis and Cross Spectral techniques were used in the analysis and prediction of estuarine morphology. The estuaries selected for study were Suisun Bay, CA and Mobile Bay, AL. It was found that EOF is an effective and efficient technique to analyze morphology, a coupling with cross spectral methods such as Fourier Transformation (FFT) resulted in determination of forcing functions responsible for imparting variance to the bathymetry. In both the estuaries it was found that the first two eigenvalues represented almost 80% of the morphological/bathymetric dataset. The second eigenfunction was found to be closely dependent on the freshwater inflows to the estuaries. EOF analysis on Suisun Bay revealed that the bay is depositional particularly in the shallow bays of Honker and Grizzly, whereas the main channels as well as Carquinez Straits maintained their depths throughout the period studied. Utilizing a Cross spectral technique, Amplitude Response Function (ARF), temporal eigenfunctions for the bay were determined for year 2100. The temporal eigenfunctions were predicted for cases where river inflows to the bay were varied by 1 standard deviation unit. These predicted eigenfunction values combined with the eigenvalues resulted in the recovery of predicted depths for year 2100. It was found that Suisun Bay remains depositional through the year 2100 and maintains depths in the main channels as well as Carquinez Straits. This depositional behavior results in the decrease of bay volume to almost 40% of the volume in 1989. EOF analysis on Mobile Bay revealed that the bay is predominantly depositional except in the navigation channel and the shoreline of the Bay. The navigation channel maintaining it depth is attributed to the regular dredging carried to facilitate shipping. The second temporal eigenfunction showed a close correlation with river inflows as in the case of Suisun Bay. However, a cross correlation performed on the second temporal eigenfunction and inflows revealed that the response of the eigenfunction is perturbed by almost 9 years, as opposed to 6 to 9 years for Suisun Bay. An ARF on the temporal eigenfunctions combined with a reverse EOF resulted in the formation of bathymetric datasets for the year 2100 for inflows variation of 1 standard deviation. It was revealed that increasing the flows results in an increase of bay volume by approximately 30% and a decrease in flows results in a loss of volume by approximately 20%.

No description available.

The purpose of this investigation is to examine how landscape architecture can create a different kind of threshold between land and water without controlling the edge between the two entities, but merely guiding the natural process of exchange. The design of Oyster Harbor on the Eastern Shore of Virginia is in contrast to normative development of waterfront sites. The hard edge of common practices of waterfront development stands in tension to the more natural evolving edge of many harbors.When creating a dialogue between land and water, the solution has always been to create a sea wall separating the two entities. It becomes the hard dividing line between a solid surface and liquid life. Is there a way to create a threshold that does not divide? How can landscape architecture create an exchange of qualities with land and water? Does the sea wall become the precedent to all concerns of tide and sea usurping lands edge? The edge between land and water is ever changing, so why not celebrate and personify that edge through creating a natural exchange between water and land. In order to create such an exchange, we must first look at the nature of water and land. Water is a free element that is composed of hydrogen and oxygen. It is inclined to motion, reflection, rise and fall. It holds a unique quality independent of man-induced control. Land is a more solid entity created by layers of stone and elements broken down by water. Land capacity is gauged by water, as in the water table. Throughout history, man has maintained a controlling relationship with land. However this is the opposite with water. Man has an inherent fear of water, the representative of both life and death. Though man tries, he cannot control water, he must work within the bounds set by water. How does one understand the evolutionary relationship of land and water without trying to control the elements that allow the relationship to occur? Through research, it is revealed that land actually usurps water through both a push and pull method of tides and water run off from land. Through time and tide, land builds up and infringes upon the natural edge of land and water. The plains move down, the vegetative roll moves forward, the beach ridges reconfigure, and the tidal flats create a shelf that extends out into the ocean floor.This evolution of land continually cycles on moon and sun paths that dictate the change in light, shade, wind, tides, motion, and human cycles. Whether recognizable or not recognizable, these macro and micro environmental cycles become a dance in the realm of landscape architecture. How does one reveal macro and micro environmental aspects through design with human interaction at the edge between land and water? / Master of Landscape Architecture