Although there has been considerable work on the role of nutrient-derived (mostly nitrate) primary production in fueling hypoxia in northern Gulf of Mexico, very little is known about the relative importance of autochthonous versus allochthonous sources of dissolved organic matter (DOM). Moreover, even less is known about the importance of dissolved organic nitrogen (DON), a critical component of DOM (along with DOC) in supporting hypoxia in this region. Most nitrogen in marine organisms exists in the form of amino acids. Changes in the spatial and temporal distribution of amino acids in the Mississippi River Plume have been shown to be important in the dynamic microbial cycling in the plume. In this study, concentrations of amino acids, DON and DOC were linked with hydrography data (e.g., DO, salinity, temperature, fluorescence) to determine how these sources of DOM are related to seasonal and diurnal changes in hypoxia on the inner Louisiana shelf. The general working hypothesis of this work was that allochthonous and autochthonous sources of DOM on the Louisiana shelf have been largely underestimated in their role in fueling hypoxia in northern Gulf of Mexico. A positive correlation between DOC, DON and fluorescence demonstrated that the main source of both DOC and DON was likely to be in situ phytoplankton production. Surface waters in the near-field showed this relationship more than at stations to the west where a sub-surface chlorophyll peak near the pycnocline may also provide a source of DOC and DON in bottom waters. DFAA always had relatively low concentrations at all water depths, which further supports prior work which has shown rapid cycling and high consumption rate of DFAA by heterotrophic bacteria. In addition to biotic controls, selective adsorption of DFAA likely contributed to the dominance of aspartic and glutamic acids at our stations. Hypoxia was generally observed in bottom waters in both spring and summer 2010. Dissolved oxygen generally revealed a negative correlation with nitrate+nitrite concentrations. Based on other work, one possible reason for such linkages may be from NH4+ released from dissimilatory nitrate reduction to ammonium (DNRA). Another possible reason may be the high degradation of labile DOM (such as DFAA) as shown by high respiration in bottom waters in prior work by Amon and Benner (1998).

The need to work with Design for Automatic Assembly (DFAA) has been widely recognizedin the literature. However, the implementation of DFAA is not clearly defined. Therefore, thepurpose of this master thesis is to investigate and contribute with knowledge of how DFAAshould be implemented into an organization, such as Company Y.Several interviews have been conducted to establish a current state analysis, to receive anunderstanding of the current problems at Company Y and how to address them. Abenchmarking study was conducted, where the three companies Ericsson, Company X andScania were interviewed. All three companies have successfully implemented DFA and wereinterviewed with the purpose to obtaining their best practices. The study also included an earlyimplementation of DFAA, where a software based DFA2-method created by Eskilander (2001)was tested on a current product and a new developed design concept at Company Y. Based onthis a recommended workflow of the evaluation could be attained.Based on the empirical gatherings several recommendations of how DFAA should beimplemented into the organization could be made. The study highlights that DFAA should beapplied as early as possible in the product development process. The DFA2-method should beutilized at product level to facilitate concept selection and at part level to make theproducts/modules suited for automatic assembly, before the design is “locked” and before aphysical prototype is created. The departments that should be working with DFAA includesindividuals from production, design quality and purchasing. However, once DFA becomesrooted in the company, more functions in the company’s supply chain will become affected.This means that more functions might need to be included in the work of DFAA. Finally, thestudy includes a decision model, in which the decisions are based on the measurable valuesreceived from the DFA2-method. / Behovet av att arbeta med Design for Automatic Assembly (DFAA) har uppmärksammat ilitteraturen. Däremot har implementeringen av DFAA inte blivit tydligt definierat. Syftet meddetta examensarbete blir således att undersöka och bidra med kunskap om hur DFAA skaimplementeras i en organisation, så som Företag Y.Flera intervjuer har genomförts för att upprätta en nuvarandeanalys för att få förståelse för derådande problemen hos Company Y och hur dessa ska hanteras. En benchmarkingstudiegenomfördes, där de tre företagen Ericsson, Company X och Scania intervjuades. Alla treföretagen har framgångsrikt implementerat DFA och har intervjuats med syftet att erhålla derasbästa praxis. Studien innefattar även en tidig implementering av DFAA, där enmjukvarubaserad DFA2-metod skapad av Eskilander (2001), har testats på en aktuell produktoch ett nytt utvecklat koncept på Company Y. Baserat på detta kunde ett rekommenderatarbetsflöde av utvärderingen presenteras.Baserat på empiriska studien kunde flera rekommendationer gällande hur DFAA skaimplementeras i en organisation skapas. Studien belyser att DFAA bör tillämpas så tidigt sommöjligt i produktutvecklingsprocessen. DFA2-metoden bör utnyttjas på produktnivå för attunderlätta konceptvalet och på komponentnivå för att göra produkterna/modulerna lämpade förautomatisk montering, detta innan designen är "låst" och innan en fysisk prototyp harkonstruerats. Avdelningar som ska arbeta med DFAA inkluderar produktion, designkvalitet ochinköp. När DFA blir rotad i företaget kommer dock fler funktioner i företagets supply chain attpåverkas. Det innebär att fler funktioner kan behöva inkluderas med arbetet kring DFAA.Slutligen så inkluderar studien en beslutsmodell relaterat till DFAA. Besluten baseras på demätbara värden från DFA2-metoden.

Nanoflagellates were found to be abundant in a coastal area of the northern Bothnian Sea. The maximum concentration of nanoflagellates, approximately 8000 cells ml-1, was observed in July, coinciding with a decrease in the abundance of cyanobacteria. Pigmented and non-pigmented nanoflagellates were approximately equally distributed throughout the year. Most of the identified genera are known as being phagotrophic, independent if autotrophic or not. A non-cyst-forming pigmented flagellate, Ochromonas sp., was isolated and nutritionally characterized. This chrysophycean flagellate was shown to be a mainly heterotrophic organism: Photosynthesis was too poor to support multiplication of the cells, whereas when feeding on bacteria, high growth rates were obtained. The biological function of the photosynthetic apparatus is suggested to be a survival mechanism during poor bacterial conditions. The flagellate grazed bacteria selectively, preferring cyanobacteria and large cells of heterotrophic bacteria, presumably depending on size-selective grazing. Despite higher growth rates of the bacteria in the sea during summer (July) than spring (May), heterotrophic bacteria in the sea was observed to be smaller in the summer. Nanoflagellates showed a maximum in July, and by selective grazing of large bacteria they might have caused the decrease in the average size of the bacteria and the decrease in the abundance of cyanobacteria. During the consumption of bacteria the flagellate was shown to remineralize nutrients at high rates and excrete dissolved free amino acids. Assuming the existence of a protozoan predator-prey chain of several trophic levels, it seems likely that a significant part of the nutrients fixed by primary producers is remineralized in the euphotic zone. Furthermore, data from this work indicate that flagellate activity may be a significant source of dissolved free amino acids, utilizable for the heterotrophic bacteria. / digitalisering@umu

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