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Novel instrumentation plays a crucial role in enabling new observations and providing deeper insights into ocean dynamics. In my thesis, I present methodologies for collecting high spatial-temporal resolution observational data, which allows for a better understanding of physical and biogeochemical processes in the coastal ocean. Specifically, I integrate two novel sensors, the acoustic Doppler current profiler (ADCP) and the Submersible Ultraviolet Nitrate Analyzer (SUNA), onto the Wirewalker (WW) wave-powered profiler. I discuss issues related to fine-scale velocity measurements, biological modulation of nitrate during a harmful algal bloom, and nitrate dynamics over the inner continental shelf.The thesis begins by presenting a new methodology to observe oceanic fine-scale velocity using the combination of velocimeters and the Wirewalker profiler. By correcting vehicle-motion-induced velocity contaminations and removing surface wave signals, a background velocity field with a spectrum wavenumber runoff at a scale of ~3 m over a 100 m vertical range was obtained. This vertical resolution is several times finer than that possible from other velocity-measuring platforms with similar measurement ranges.Next, I present in situ evidence demonstrating the vertical migration of the dinoflagellate that facilitates their nitrate uptake during the 2020 red tide in the Southern California Bight. The vertical migration pattern of Lingulodinium polyedra (the dominant species) and their biological modulations to the subsurface nitrate field were quantified. The loss of nitrate in the nitracline was balanced by proportional increases in phytoplankton concentrations, confirming a 50-year-old hypothesis. The swimming ability of the dinoflagellate allows them to outcompete other non-motile phytoplankton during times of high stratification and nutrient limitation.Finally, an undocumented onshore-directed cross-shore nitrate gradient over the inner shelf of the Southern California Bight was revealed. The nitrate gradient was possibly formed by enhanced vertical nitrate flux due to elevated turbulent diffusivity when isopycnals constantly impinged on a sloping sea floor. Furthermore, the study demonstrated that near-inertial internal waves were responsible for transporting the onshore nitrate offshore, providing a new mechanism for fueling the offshore primary productivity. These findings highlight the need for new instrumentation to better understand complex coastal biogeochemical dynamics.

The Lesser White-fronted Goose Anser erythropus, which breeds across northern Eurasia from Norway to Chukotka, is globally threatened and is currently classified as Vulnerable by the International Union for Conservation of Nature. The Eastern Palearctic population of the species was thought to breed in arctic Russia, from east of the Taimyr Peninsula to Chukotka, and to winter in East Asia, but its precise status, abundance, breeding and wintering ranges, and migration routes were largely unknown, reducing the effectiveness of conservation efforts. In this paper, we combined results from satellite tracking, field surveys, a literature review and expert knowledge, to present an updated overview of the winter distribution and abundance of Lesser White-fronted Geese in the Eastern Palearctic, highlighting their migration corridors, habitat use and the conservation status of the key sites used throughout the annual cycle. Improved count coverage puts the Eastern Palearctic Lesser White-fronted Geese population at c. 6,800 birds in 2020, which represents a rapid and worrying decline since the estimate of 16,000 in 2015, as it suggests at least a halving of numbers in just five years. East Dongting Lake (Hunan Province) in China is the most important wintering site for the species in East Asia, followed by Poyang Lake (Jiangxi Province) and Caizi Lake (Anhui Province), with one key wintering site in Miyagi County in Japan. Satellite tracking showed that eight individuals captured during summer on the Rauchua River, Chukotka, Russia wintered in the middle and lower reaches of the Yangtze River floodplain in China. Their migration speed was slower in spring than in autumn, mainly because of longer stopover duration at staging sites in spring. The tracked geese mainly used cultivated land on migration stopovers (52% in spring; 45% in autumn), tundra habitat in summer (63%), and wetlands (66%) in winter. Overall, 87% of the GPS fixes were in protected areas during the winter, far greater than in spring (37%), autumn (28%) and summer (7%). We urge more tracking of birds of differing wintering and breeding provenance to provide a fuller understanding of the migration routes, staging sites and breeding areas used by the geese, including for the birds wintering in Japan. The most urgent requirement is to enhance effective conservation and long-term monitoring of Lesser White-fronted Geese across sites within China, and particularly to improve our understanding of the management actions needed to maintain the species. Collaboration between East Asian countries also is essential, to coordinate monitoring and to formulate effective protection measures for safeguarding this population in the future.

European populations of the Greylag Goose Anser anser have been studies for over 50 years, but those in the East Asian flyway are less well known. Here we describe the breeding and wintering distribution of Greylag Geese wintering in China, based on historical and newly-reported telemetry data (from 31 individuals contributing complete migrations), wintering waterbird surveys and expert knowledge. Historical records, and also the data presented here, indicate that Greylag Geese breeding in the north of the Xinjiang Uygur Autonomous Region, China, and in Mongolia east of 93°E, through Inner Mongolia to western parts of Heilongjiang Province, China, likely almost all winter east of 107°E in China (97% in the Yangtze River floodplain and 3% in the Yellow River floodplain). Annual mid-winter waterbird counts confirm that very few Greylag Geese winter in Japan and South Korea. Count data suggest that the Far East Asia Greylag population wintering in China currently numbers 30,000 individuals, a major increase compared to 3,263 counted in 2005. Historical records however indicate that the wintering distribution was far greater 30 years ago, and that Greylag Geese are now less common than previously in Guangdong, Guizhou, Hainan, Henan, Hunan, Anhui and Jiangsu Provinces, as the species has become more concentrated further north in the Yangtze and Yellow River floodplains. On the basis of count data from winters 2010/11–2019/20, we identified 21 current key wintering sites (holding ≥ 1% of the flyway population, i.e. 300 birds) in the Yangtze River floodplain and one in the Yellow River floodplain for this population. Increasing use of farmland in winter, as well as site protection and sympathetic local management of wintering sites may have contributed to recent increases in Greylag Goose abundance in the flyway. These results provide a more robust basis for assessing the current status of the Far East Asia Greylag Goose population and a guide to priorities for further internationally coordinated research of the species. The need to improve monitoring and habitat management for maintaining the increasing numbers wintering in China is also emphasiseduropean populations of the Greylag Goose Anser anser have been studies for over 50 years, but those in the East Asian flyway are less well known. Here we describe the breeding and wintering distribution of Greylag Geese wintering in China, based on historical and newly-reported telemetry data (from 31 individuals contributing complete migrations), wintering waterbird surveys and expert knowledge. Historical records, and also the data presented here, indicate that Greylag Geese breeding in the north of the Xinjiang Uygur Autonomous Region, China, and in Mongolia east of 93°E, through Inner Mongolia to western parts of Heilongjiang Province, China, likely almost all winter east of 107°E in China (97% in the Yangtze River floodplain and 3% in the Yellow River floodplain). Annual mid-winter waterbird counts confirm that very few Greylag Geese winter in Japan and South Korea. Count data suggest that the Far East Asia Greylag population wintering in China currently numbers 30,000 individuals, a major increase compared to 3,263 counted in 2005. Historical records however indicate that the wintering distribution was far greater 30 years ago, and that Greylag Geese are now less common than previously in Guangdong, Guizhou, Hainan, Henan, Hunan, Anhui and Jiangsu Provinces, as the species has become more concentrated further north in the Yangtze and Yellow River floodplains. On the basis of count data from winters 2010/11–2019/20, we identified 21 current key wintering sites (holding ≥ 1% of the flyway population, i.e. 300 birds) in the Yangtze River floodplain and one in the Yellow River floodplain for this population. Increasing use of farmland in winter, as well as site protection and sympathetic local management of wintering sites may have contributed to recent increases in Greylag Goose abundance in the flyway. These results provide a more robust basis for assessing the current status of the Far East Asia Greylag Goose population and a guide to priorities for further internationally coordinated research of the species. The need to improve monitoring and habitat management for maintaining the increasing numbers wintering in China is also emphasised.

It is of great concern to reduce greenhouse gases (GHG) and ammonia (NH3) emissions from animal manure composting in China. The purpose of this study was to investigate effects of adding red mud on emissions of GHG (methane (CH4), nitrous oxide (N2O)) and NH3 in full-scale swine manure windrow composting. Two full-scale swine manure windrow composting experiments were carried out to compare emission of GHG and NH3 with and without addition of red mud. Results showed that the addition of modified red mud reduced N2O emissions by 4.03%, however, it did not help reduce CH4 emissions (51.65% higher than that of the control test). Ammonia emission from both the experimental and the control tests were similar. The addition of modified red mud was useful to conserve nitrogen and phosphorus because the contents of total nitrogen and total phosphorus in the compost of the experiment test were higher than the control test. It was also found that turning was useful to reduce CH4 emissions, i.e. 51.72% reduction of CH4 emission after turning compared to before turning. However, turning resulted in an increased N2O emission flux by 23.15 times in the experiment test and 15.31 times in the control test, respectively.

Forest ecosystems provide a variety of services and forest ecosystem man- agement (FEM) is an effective approach to maximize the services. Because of the com- plexity of forest ecosystems, the applications of FEM can be facilitated with decision support systems (DSS) that recognize and incorporate ecological and socio-economic variables. With the rapid development of computation and information technologies, DSS have been advanced in many ways. Traditional forest management within a forestry unit in China is planned on a yearly basis. The planning itself remains primarily a verbal concept as there are no quantitative decision-support tools available to translate the concept into forest management actions. For the purposes of FEM at the management level, a forest management DFF, FORESTAR ® , has been developed under a framework of geographic information system (GIS) and forest models. The paper explained the intelligent modeling mechanisms and demonstrated how the applications of FEM can be strengthened with the applications of FORESTAR ® .