L'evolució del paisatge producte dels canvis d'usos recents, que fonamentalment significa el pas de la utilització agrària a l'abandonament, és una realitat que afecta una part molt important del món rural en el nostre àmbit. En menys d'un segle s'ha passat d'una economia en la qual el sector primari tenia un pes molt important a una societat terciaritzada. És a dir, que l'ús del territori ha variat dràsticament, i això té implicacions en el present, però també suposa dinàmiques a llarg termini que no sempre són fàcils de preveure a partir de la imatge que tenim en els nostres dies, ja que aquesta evolució no és lineal.En aquest treball s'ha volgut entendre els mecanismes que governen l'evolució del paisatge de muntanya lligat al canvi d'usos que s'hi dóna. Per fer això s'han plantejat els següents objectius: Valorar les diferències de l'evolució del paisatge en relació a les variables geoecològiques de la zona; Valorar la incidència de l'activitat antròpica en el zona d'estudi i les repercussions que aquesta ha tingut en el paisatge actual i en el futur i; Definir les variables geomorfològiques que tenen major influència en tot aquest procés.El Parc Natural de Sant Llorenç del Munt i la Serra de l'Obac és la zona sobre la qual s'ha treballat el canvi de paisatge. Aquesta zona ocupa una extensió de 13.000 ha a la serralada Prelitoral Catalana, a cavall de les comarques del Vallès Occidental, Oriental i del Bages. La litologia està dominada per conglomerats eocènics i per intercalacions de gresos i lutites continentals, que tan sols apareixen coberts de materials quaternaris en els fons de vall i als col·luvions; i la vegetació està constituïda per boscos i bosquines escleròfiles mediterrànies amb comunitats típiques d'alzinars, garrigues i brolles, de les quals l'alzinar n'és la vegetació potencial, que està molt alterada per la presència de boscos secundaris de pi blanc.Per treballar amb els objectius proposats s'ha utilitzat el vector sòl i el vector aigua. Per al primer s'han traçat un conjunt d'àrees homogènies en funció de la vegetació, la litologia, el pendent, la geoforma, l'orientació i situació geogràfica, el que ha donat un total de 108 àrees d'estudi. Per al segon paràmetre s'ha treballat amb set conques hidrogràfiques diferents amb els següents usos: roca nua, alzinar, pineda, bosquina, camps de conreu actius i camps de conreu abandonats. La cartografia dels usos del sòl necessària per elaborar totes aquestes àrees s'ha fet amb ArcView a partir de la digitalització d'ortofotomapes 1:5.000, del Model Digital d'Elevacions i diversa cartografia temàtica. A les àrees homogènies s'ha treballat amb la fertilitat del sòl, la humitat i la seva capacitat d'infiltració; i a les conques hidrogràfiques s'ha mesurat els paràmetres fisicoquímics.A partir dels resultats obtinguts s'han ressaltat les següents conclusions. En el camp de la inèrcia temporal dels trets que caracteritzen el paisatge, s'ha vist que les formes vegetals al parc donen uns paisatges visuals que no es corresponen directament amb les característiques naturals que els composen. Hi ha un grup de paràmetres edàfics que diferencien clarament els sòls en funció del usos, i són la matèria orgànica, la relació carboni/nitrogen i la fertilitat química. Pel que fa a l'exportació de nutrients, a les conques naturals es dóna un nivell de protecció per part de les bosquines comparable al de les conques arbrades, i a les conques antròpiques es dóna els mateixos valors en les dues conques analitzades de camps de conreu actius, i en les conques de camps abandonats uns valors similars, el que posa de manifest la perseverància de les dinàmiques. Dels elements analitzat en els mostreigs d'aigua els que separen millor el binomi natural-antròpic són el residu sec, la conductivitat elèctrica, els carbonats i bicarbonats, i el magnesi. / Landscape evolution due to changes in recent land uses, it is a reality that affects a very important part of the rural world in our areas. In less of a century one has gone of an economy in which it is primary sector had a very important weight to a society of the tertiary sector. In fact, the use of the territory has varied a lot and this has implications in the present, but also it supposes dynamics in a long term that not always they are easy to see from the image that we have in our days, because this evolution is not linear.In this work it has been wanted to understand the mechanisms that govern the evolution of the mountain landscape related to the changes of uses that occur. In order to do this the following objectives have considered: value the differences of the evolution of the landscape in relation to the geoecological variables of the area; value the incidence of the anthropic activity in the zone of study and the repercussions that this has had in the present landscape and the future and; to define the geomorfological variables that have greater influence in all this process.The Natural Park of Sant Llorenç del Munt is the zone on which the change of landscape has worked. This zone occupies an extension of 13000 hectares in the Catalan Precoastal Mountain Range, in Vallès Occidental, Vallès Oriental and Bages County (comarca). Lithology is dominated by Eocenic Conglomerates and limestone and continental lutites, that just appear cover of quaternary materials in the bottoms of valleys; and the vegetation is constituted by mediterraneous forests with typical communities of evergreen oak, but very altered by the presence of secondary forests of pine.In order to work with the proposed objectives it has been used soil and water. For first a set of homogenous areas based on vegetation, lithology, slope, direction and geographic situation has drawn up, it has given a total of 108 areas of study. For the second parameter has worked with seven catchments different with the following land uses: rock, evergreen oak, pine, scrub, active fields and abandoned fields. The cartography of land uses, necessary to elaborate all these areas, has taken control of ArcView from the digitalization of maps 1:5000, of the Digital Model of Elevations and diverse thematic cartography. In the homogenous areas has worked with soil fertility, humidity and its capacity of infiltration; and in the catchments the physical and chemical parameters have been analysed.From the results that we get, the following conclusions have been emphasized. The temporary inertia of the landscape characteristics, one has seen that the vegetal forms of the park give visual landscapes that do not correspond directly with the natural terrain features that compose them. There is a group of edaphic parameters that differentiate clearly soils based on land uses, they are organic matter, relation carbon/nitrogen and chemical fertility. With respect to the export of nutrients, in the natural catchments a level of protection on the scrubs is comparable to the forest zones, and in the anthropic catchments values in the two analysed catchments of fields, and in the catchment of abandoned fields occur such similar values, which shows the dynamic ones. The elements analysed in the water samplings, those that better separate the natural-anthropic binomial are the dry remainder, the electrical conductivity, the carbonates and bicarbonates, and the magnesium.

The aim of this report has been to investigate the use of electricity energy before and after a conversion of foodservice. The ambition was also to highlight the food safety and the retention of nutrients in relation to the conversion. The methods being used were qualitative interviews, case studies, study visits and literature. The equipment and the use of energy was the same in 2008 as in 2011 for hot-holding of the tested component, sauce with ham. The chilled system used more than three times the energy and cost for one portion than one portion in the hot-hold system. The food safety is all about routines and quality programs, of course the chilled system must have more critical control points. Nutrients are often labile when heating, especially water-soluble vitamins. Vitamin C showed losses in each step in both systems. The conclusion is that the combined system is much more energy-demanding than the hot-holding. There are concerns in both systems on food safety and retention of nutrients. Used as here, with only the main component chilled and the rest of the meal prepared where the meal is served, the chilled system seems to give better quality than a hot-holding system from nutrition- perspective. Maybe the greatest gain in food safety and retention would be to have cooking kitchen in most schools.

The main objective of this project was to investigate the effects of the type of dried distillers grains with solubles (wheat DDGS, corn DDGS, and blend DDGS (eg. wheat:corn = 70:30)) and bio-ethanol plant origin on the nutrient variation and availability in ruminants. In addition, DDGS products were studied as opposed to their parental grains. The project was divided into the several following studies. In Study 1, we studied the nutritive value of DDGS products in terms of (1) chemical profiles, (2) protein and carbohydrate sub-fractions associated with different degradation rates, and (3) digestible component nutrients and energy values using the NRC 2001-chemical approach and the in situ assay-biological approach. Also, we tested the validity of acid detergent insoluble crude protein (ADICP) and acid detergent lignin (ADL) to predict the potential degradability of DDGS. Due to starch fermentation in the ethanol process, the chemical components in DDGS became approximately threefold more concentrated than in feedstock grains. Slowly degraded protein (PB3) and unavailable protein (PC) increased in DDGS, indicating a decrease in the overall protein degradability in the rumen. Intermediately degraded protein (PB2) was higher for corn DDGS than for wheat DDGS and blend DDGS (54.2 vs. 27.7 vs. 30.8 %CP), while PB3 was higher for wheat DDGS and blend DDGS (29.9 vs. 51.2 vs. 53.2 %CP). Mainly as a result of differing heat conditions, PC differed significantly between wheat DDGS originated at different bio-ethanol plants (0.7 vs. 7.6 %CP). The prediction of truly digestible CP (tdCP) and NDF (tdNDF) differed between the NRC 2001-chemical approach and the in situ assay-biological approach; however, both approaches reported similar energy values. These values were the highest for corn DDGS (DE3X: 3.9 Mcal kg-1), followed by blend DDGS (DE3X: 3.6 Mcal kg-1), and wheat DDGS (DE3X: 3.4 Mcal kg-1). Corn DDGS was superior to corn, wheat DDGS was similar to wheat and corn, and blend DDGS was similar to corn. No significant differences in energy values were reported between bio-ethanol plants. ADICP was not an accurate indicator of the potential degradability of protein in DDGS samples, while ADL seemed to be an acceptable indicator of the potential degradability of DM (r = -0.87; P<0.01), CP (r = -0.89; P<0.01), and NDF (r = -0.82; P<0.01) in wheat DDGS samples incubated in rumen during 48 h.<p> In Study 2, we studied the ruminal and intestinal digestion profiles and the hourly effective rumen degradation ratios between nitrogen (N) and energy. The results showed a reduction in the effective degradability of DM (EDDM), OM (EDOM) and CP (EDCP) of wheat DDGS relative to wheat; however, corn DDGS remained the same as corn. The effective degradability of NDF (EDNDF) did not vary between the DDGS samples and feedstock grains. Among DDGS types, EDDM ranged from 52.4 to 57.7 %, EDOM from 46.4 to 53.5 %DM, and EDCP from 34.0 to 45.6 %CP, being higher as the proportion of wheat in feedstock increased. No significant differences in EDDM, EDOM, EDCP and EDNDF for wheat DDGS were detected between the different bio-ethanol plants. The hourly effective degradability ratios between N and energy indicated a potential excess of N in rumen when DDGS samples were evaluated as single ingredient. This excess increased as the proportion of wheat in feedstock increased. Estimated intestinal digestibility of rumen bypass protein (IDP) was similar between wheat and wheat DDGS, but higher in corn DDGS than in corn. Blend DDGS had the highest IDP (93.9 %RUP). Due to the significantly different PC sub-fraction found in wheat DDGS originated at the different bio-ethanol plants, a large but numerical difference was detected in IDP (89.4 vs. 75.9 %RUP).<p> In Study 3, we used both the DVE/OEB System and the NRC 2001 Model to reveal the metabolic characteristics of DDGS protein and predict the protein supply to dairy cattle. The two models showed higher protein values (DVE or MP) for DDGS samples than for feedstock grains. The higher IDP for blend DDGS largely contributed to the higher protein value relative to wheat DDGS and corn DDGS (MP: 277 vs. 242 vs. 250 g kg-1 DM). Similarly, protein values differed significantly between the bio-ethanol plants mainly as a result of the numerical but large difference in IDP (MP: 272 vs. 223 g kg-1 DM). According to the two models, the degraded protein balance for DDGS products was higher than in the parental grains. Wheat DDGS showed the highest potential N excess (DBPNRC: 78 g kg-1 DM). For corn DDGS, however, the DVE/OEB System suggested a potential N excess (11 g kg-1 DM) while the NRC 2001 Model exhibited a potential N deficiency (-12 g kg-1 DM). The degraded protein balance for wheat DDGS was similar between the different bio-ethanol plants.<p> In conclusion, the chemical and biological characteristics of DDGS varied among types and between wheat DDGS samples manufactured at the different bio-ethanol plants. Thus, it is inappropriate to assume fixed values for the nutritive value of DDGS without considering factors such as type of grain used and bio-ethanol plant origin. Further research with higher number of samples will help to clarify the use of the chemical profile to predict energy values and the potential degradability of DDGS.

Phosphorus (P) is a limiting nutrient regulating productivity in both freshwater and marine ecosystems. A full knowledge of the sources and pathways of the P cycle is essential for understanding aquatic ecosystem function and for managing eutrophication. However, two significant pathways are poorly understood or remain uncharacterized. First, aquatic metazoans represent a significant internal regenerative pathway of P through the mineralization, translocation (i.e., benthic pelagic coupling) and excretion of nutrients. Rates of P excreted are expected to vary across taxa (i.e., zooplankton vs. mussels vs. benthic macroinvertebrates vs. fish), yet the significance of any one group of taxa in supplying P to bacteria and algae is unknown. Therefore, I developed the first comprehensive set of empirical models of nutrient release for aquatic metazoans (zooplankton, mussels, other benthic macroinvertebrates, and detritivorous and non-detritivorous fish) and compared inter-taxonomic differences in P excretion. I demonstrated that detritivorous fish excrete P at rates greater than all other taxa (as a function of individual organism mass); whereas, mussels generally excreted P at rates less than other taxa. Significant differences in the rate of P excretion between zooplankton and non-detritivorous fish were not observed [i.e., the allometry of P excretion was similar between zooplankton and non-detritivorous fish (as a function of individual body mass)]. I subsequently applied the models to assemblage biomass and abundance data to examine and compare the relative contribution of each taxa to the internal supply of P, and to examine the turnover time of P bound in metazoan biomass. I clearly demonstrated a hierarchy in the contribution by different metazoan assemblages to P cycling (zooplankton > benthic macroinvertebrates > mussels > fish) and clarified the significance of different metazoan taxa in P cycling. Moreover, I demonstrated that the slow turnover time of P bound in fish biomass (relative to other metazoans) indicates that fish are important as sinks rather than sources of P. A second potentially significant P pathway is through the influence of ultraviolet radiation (UVR) on P cycling. UVR may alter P cycling abiotically through changes in P availability and biotically through changes in the acquisition and regeneration of dissolved P by plankton. However, the significance of P released from the photodecomposition of dissolved organic P compounds (DOP), and the effect of UVR on the uptake and regeneration of dissolved P, the turnover of particulate P, and on ambient phosphate (PO43-) concentration has not been investigated and remains unknown. Therefore, my initial experiments applied the novel use of radiophosphate uptake assays to quantify the significance of the photodecomposition of DOP to PO43-. I concluded that the liberation of PO43- through the photodecomposition of DOP is not a significant pathway. However, the photochemical liberation of PO43- from suspended sediments was evident and should be an important pathway supplying PO43- to plankton in shallow polymictic lakes. This represents the first study to identify this P pathway in lakes. The turnover time of the PO43- pool increased under UVR irradiance (i.e., uptake of P by plankton decreased), while the regeneration rate of dissolved P and turnover rate of planktonic P were generally not affected. The net effect of UVR was an increase in steady state PO43- concentration (ssPO43-). Alkaline phosphatase activity (APA) in the dissolved and particulate fractions was significantly reduced in UVR treatments, but unrelated to changes in P uptake as proposed in the literature. This is the first study to comprehensively investigate the biotic effects of UVR on P cycling and represents a major advancement in the field of photobiology. In summary, I have characterized several poorly understood pathways in the P cycle of lakes. With the models I have developed, aquatic metazoans can now be integrated into the P cycle of lakes, for example, with other internal and external sources of P (e.g., from inlets, lake sediments and the atmosphere). This will advance our knowledge of P cycling, and will provide researchers with a better understanding of the nutrient pathways supporting primary production.

The polluted agricultural wastewater, after reaching marine recipients, can cause eutrophication. This problem can be tackled and mitigated by using constructed wetlands as water treatment systems. The fact that constructed wetlands work through long periods of time has led many scientists to evaluate how long they can still treat their influents effectively. The development and growth of vegetation and the accumulation of nutrients on the soils in a wetland are expected to occur. These processes change the wetland efficiency to remove pollutants. In this study, a set of wetlands constructed to treat agricultural wastewater were analyzed in different periods to assess if there is a difference in removal efficiency of nitrogen and phosphorus. This assessment was performed by analyzing the retention rate, k and k20 values, which are variables that quantify the nutrients removal, in different periods of each employed wetland. Some of the observations demonstrated differences when comparing different periods of the wetlands. The nitrogen removal presented better performance in one of the employed wetlands when this was older. Another employed wetland has not shown a clear difference between different periods. In the wetlands with high vegetation densities, the nitrogen removal was more stable over consecutive years. The occurrence of oscillations in nitrogen removal was observed more often in the wetlands with the highest vegetation densities over consecutive years. The phosphorus removal presented no clear differences between different periods. The results suggest that the removal of nitrogen improves after wetland creation due to the growth of vegetation. In addition, they suggest that wetlands with high vegetation densities tend to oscillate the nitrogen removal more or less often according to the density of the vegetation due to the balance between denitrification and decomposition. Further, the results suggest that the removal of phosphorus remains unchanged over longer periods than the periods considered in this study (four to six years) due to the deposition of organic matter on the soils.

Before January 2003, the Dapeng Bay lagoon was occupied by oyster culture racks and fish farming cages. Along with the development of the Dapeng Bay National Scenic Area Administration, the government has started taking actions on removing oyster culture racks, and has kept improving the quality of lagoon water. Nowadays, the government is implementing sediment dredging plan. As to discuss the change of biogeochemical processes, this study is divided by three parts, including the first stage, before the removal of oyster culture rafts; second stage, after the removal of oyster culture rafts, and the third stage, after implementation of sediment dredging. At the first stage, the annual mean of water exchange time at the Dapeng Bay was approximately 10 days. At the second and third stage, the annual mean of water exchange time were 6.2 days and 8.3 days, respectively. The difference is not significant between the second stage and third stage. The trend of water exchange time is similar to the seawater exchange rate. Distributions of chlorophyll a were controlled by temperature and solar radiation, rather than by nutrient concentration throughout three-stage periods. Although the change tendency between chlorophyll a, DIN, and DIP at the third stage is similar, chlorophyll a correlated positively with DIN and DIP only in fall. The net ecosystem production (NEP) was positive (p¡Ðr > 0) at all three stages, so the Dapeng Bay was always an autotrophic system throughout the study period. Before the removal of the oyster culture racks, the NEP was 5.64 mole C m-2 yr-1, after that, it increase to 11.64 mole C m-2 yr-1. During the sediment dredging period, the NEP was 14.31 mole C m-2 yr-1. The NEP increases 106 % from the first stage to the second stage, and increases 23% from the second stage to the third stage. The environmental remediation appears to produce significant influence on NEP. The concentration of DIN¡BDSi¡BDIP decreases by removing the oyster culture of racks. But the concentrations of particulate and dissolved organic carbon and nitrogen increase sharply after removing the oyster culture racks. Nevertheless, the concentration of dissolved organic carbon, nitrogen and the phosphorus decreases during the third stage, resulted mainly from the improvement of water quality. The system changed from the condition of phosphorus surplus (Si/N=1.8¡Ó1.2 and N/P=7.4¡Ó5.2) during the first and second stage to the condition of phosphorus limitation (Si/N=1.0¡Ó1.2 and N/P=22.2¡Ó18.7) during the third stage. The ratios of particulate organic carbon and nitrogen (POC/PN) are 7.7¡Ó1.1, 8.0¡Ó1.0, 6.5¡Ó1.3, respectively. The ratio at the third stage is very close to the Redfield ratio (C/N=6.6), which may result from the improvement of water quality. In terms of temporal and spatial variation of various parameters, DO variability was strong in the time scale than in the spatial scale, but nutrients and POC show a decrease of spatial variability from the first stage to the third stage. The removal of oyster culture racks, and the implementation of sediment dredging plan at the Dapeng Bay have significant influence on the improvement of lagoon environment for the past ten years.

This study focuses on the relationship between hydrological and nutrient conditions in seawater surrounded by Dongsha Atoll. Dongsha Atoll is located in the northern South China Sea (NSCS), the water properties should be in coherence with the NSCS water masses. However, due to the semi-enclosed topography the water inside Dongsha Atoll is largely affected by local insolation and rainfall. Significant relationships between SiO2 or PO43- and salinity indicate that rainfall could be a major source of these nutrients. Insignificant relationship between N+N and salinity indicates that rainfall and nitrogen fixation both might affect the distribution of N+N. Temporal variations of temperature and chlorophyll a were alike, except for which occurred in July, 2011. It was probably caused by photo inhibition on phytoplankton growth. The inventory of chlorophyll a was positively correlated with both N+N and SiO2 but not with of PO43-, indicating that phytoplankton growth in Dongsha Atoll was mainly affected by N+N and SiO2. Phytoplankton growth maybe limited by N+N but not by SiO2, as the concentration of SiO2 was mostly beyond the limitation concentration for phytoplankton. According to close relationships between chlorophyll a and TSM, POC and PN, the particulate matter maybe mainly derived from biological origins. The inventory of chlorophyll a was positively correlated with both dissolved organic carbon (DOC) and dissolved organic nitrogen (DON), manifesting the importance of biological origins for DOC and DON concentration. The ratios of DOC/DON, DON/DOP and DOC/DOP within the atoll were in ranges of 7.34-303 (mean: 30.4), 3.00-142 (mean: 22.7) and 104-2546 (mean: 421), respectively. The ratios are higher than those values in NSCS and East China Sea, implying the excretion of carbon-enriched DOM by phytoplankton. The concentration of chlorophyll a, DOC and POC were higher in the Small Lagoon than in the Atoll Lagoon, implying a relatively high productivity in the Small Lagoon. The fluxes of carbonate in the atoll was more than 30 times of the flux in the NSCS, due to its unique characteristics in the coral reef habitat. The organic matter of settling particulates was mainly derived from biological sources. The metal of enrichment factor of settling particulates reveals that Fe and Al are mainly derived from crustal sources, while Cu, Zn and Pb are likely influenced by anthropogenic sources.

Freshwater inflows are essential to the health of estuaries and minimum discharge levels must be maintained in order to sustain a healthy ecosystem. Due to the predicted 50% increase in urban population growth along the Texas coastline by the year 2050, water regulators and managers are faced with the challenge of meeting human needs, while maintaining essential freshwater inflows into estuarine ecosystems. Galveston Bay is of particular concern because 10 million people currently living within its watershed. Freshwater inflows into Galveston Bay during 2006 were determined by using daily discharge data from a United States Geological Survey (USGS) sampling gauge in the Trinity River. Changes in water quality parameters, primary productivity, and phytoplankton community structure in response to freshwater inflows, were monitored monthly to determine how the phytoplankton community responded to inflow events. Freshwater inflow into Galveston Bay during 2006 was indicative of a low-inflow year, with seven large (>7,000 ft.3 sec-1) inflow events occurring throughout the year. There were significant differences in phytoplankton biomass (Fm), photosynthetic efficiency (alpha), and photosynthetic potential (yield) of the phytoplankton community, between wet (January-April and October-December) and dry (May-September) months. Significant differences in the biomass of phytoplankton groups also occurred with cyanobacteria being present in higher concentrations during the dry months and diatoms & dinoflagellates during the wet months. Low flow periods favored cyanobacteria, which lead to decreased secondary productivity, while pulsed inflow events resulted in enhanced secondary productivity by favoring diatoms and dinoflagellates. Resource Limitation Assays (RLAs) indicated that nitrogen was a potential limiting nutrient in Galveston Bay during spring/summer, with light limitation of phytoplankton communities possibly occurring near the mouth of the Trinity River. This study demonstrates the role of freshwater inflows in determining the primary productivity and community composition of the phytoplankton in Galveston Bay over an annual cycle. Inter-annual studies are needed to elucidate the impact of freshwater inflows in years with higher inflows to Galveston Bay and determine which of these impacts need to be incorporated into water management decisions to maintain a healthy ecosystem.

This study aims to understand the role of the Tapong Bay on carbon biogeochemical cycle in the coastal zone and the influence of terrigenous inputs on ecosystem functioning in the Tapong Bay. The Tapong Bay is a semi-enclosed lagoon, occupied largely by fish farming cages and oyster culture racks. There is only one tidal inlet for exchanging water between the Tapong Bay and Taiwan Strait, which results in a low water exchange rate and oxygen deficient condition in the bottom water of the inner bay. The annual mean of water exchange time is about 10.6 days that is much longer than that in the Chiku Lagoon (5.8 days). Experimental results show that biological activity and variations of hydrochemistry primarily control the distributions of carbon and nutrients. Excess of DIP likely occurred in the Tapong Bay. Seasonal variations of primary productivity are apparently controlled by temperature, solar radiation and turbidity. The regression slope between particulate organic carbon and nitrogen approaches the Redfield ratio, indicating that organic carbon is derived primarily from biological production. The stratification of water column in the Tapong Bay was observed throughout the year. Diffusion from sediment may thus contribute significantly to nutrient distributions in bottom water. Diffusion flux estimated from porewater to bottom water is about 7.6% of annual mean input for DIN and is about 1.0% for DIP. Calcification process was observed in the Tapong Bay indicating that the oyster culture would affect the carbon budget in the bay. The annual mean production rate of organic carbon estimated from the biogeochemical model is about 5.80 mole C m-2 yr-1, implying that the Tapong Bay is an autotrophic system. The net ecosystem production (NEP) derived from diel observation is about 6.29 mmole C m-2 d-1 that is closed to 6.65 mmole C m-2 d-1 estimated from the biogeochemical modeling. The annual nitrogen fixation exceeds the annual denitrification [(nfix-denit)¡×1.30 mole m-2 yr-1] in the Tapong Bay. Carbon biogeochemical fluxes and budgets differ significantly between the Tapong Bay and the Chiku Lagoon, which may be arisen from pronounced difference in terrigenous inputs and seawater exchange rates.

Abstract Constructed wetlands can be treated as a imulated natural treatment system,which use solar adiation as the source of energy. By analogy with some removalmechanisms in natural wetlands, constructed wetlands are able to transform and remove pollutants from the wastewater. Other features provided by the constructed wetland include wildlife support, hydrologic odification, erosion protection, and open space and aesthetics. It has been applied for domestic wastewater purification for decades. The goal of this study was to evaluate the ffectiveness of using constructed wetlands on industrial wastewater treatment. In this study, grit chamber and furnace waste from steel-making were used as the media for plant growth. Two -tank (dimension for each tank: 4L ¡Ñ1W ¡Ñ1H) system was designed and constructed to simulate the constructed wetland. Reed and cattail were planted in the first and second tanks, respectively. In the system, media in the first and second tanks were filled to a height of 0.4 m (furnace waste from steel-making) and 0.1 m (waste grit), respectively. The depth of water was maintained at 0.3 m. The hydraulic retention time was approximately 5 days. The following parameters were analyzed during the operational period: nutrients, chemical oxygen demand (COD), suspended solids (SS), and biochemical oxygen demand (BOD). The calculated removal rates (g/m2/day) in the first tank were¡GCOD 5.92¡Ó0.64¡BBOD 3.48¡Ó0.95¡BSS (suspended solids) 3.42¡Ó1.44¡BTKN (total kjedal nitrogen, TKN) 0.94¡Ó0.26¡BTP (total phosphorus) 1.33¡Ó0.2¡CThe removal rates (g/ m2/day) in the second tank were: COD 5.17¡Ó0.62¡BBOD 3.21¡Ó0.92¡B SS 2.92¡Ó1.29¡BTKN 0.59¡Ó0.21¡BTP 0.66¡Ó0.15. Results from this study indicate that the media and plants in both tanks created a biofiltration system for microbial growth and pollutant removal. Sorption and biodegradation were the two major pollutant removal mechanisms in the system. During the operational period, the average removal efficiencies (%) in the first tank were: COD 55~62, BOD 73~90, SS 66~84, TKN 36~66, TP 28~39. The average removal efficiencies (%) in the first tank were: COD 49~54, BOD 73~83, SS 45~69,TKN 15~43, TP 9~24.