Temporal and spatial variations in the taxonomic composition, standing stocks (abundance and biomass), and protein synthetases activity of the mesozooplankton community in the northern Satsunan area were investigated. Although both variations in sources were significant for their standing stocks, temporal variability was predominant for their protein synthetases activity. A multivariate analysis on their taxonomic compositions identified six groups with large seasonality at the mouth of the Kagoshima Bay and two groups with less temporal variability. These were characterized by calanoids and poecilostomatoids. The mesozooplankton community demonstrated a higher abundance and biomass inside as compared to the outside of the Kagoshima Bay. However, similar protein synthetases activity was seen for both locations. Mesozooplankton protein synthetases activity was high, even when there was a low chlorophyll a average in the sampling layer owing to the increased presence of smaller mesozooplankton. In the sampling layer, individual body mass was lower and mesozooplankton abundance was higher at lower salinity averages. These results suggest that the temporal and spatial variations in the mesozooplankton standing stocks and protein synthetases activity are associated with the advections or extensions of small calanoids and poecilostomatoids with less saline waters.

The “microbial loop” is an important system that drives the carbon cycle in the ocean, and consists of dissolved organic matter, bacteria, protists and viruses. The starting point of the system is organic matter (OM). The OM is utilized by bacteria, which are then bacteria are transferred to higher trophic levels by protistan grazing. One of the functional bacterial groups, aerobic anoxygenic phototrophic bacteria (AAnPB)，is ubiquitously distributed in the global ocean surface, grow rapidly, and can be regarded as a key player in driving the carbon cycle in the ocean. Herein, the eco-physiological characteristics of AAnPB (e.g., large cell size, rapid growth, long-term survival, wide phylogenetic diversity, and unique carotenoids composition) are summarized and its survival strategy discussed.

Recent studies show that Antarctica is losing ice, which is contributing to global sea level rise at a rate of approximately 0.3 mm yr^­-1. The main cause of this ice loss is on-shelf intrusions of warm ocean water. This water flows into ice shelf cavities and causes melting, which thins the ice shelves. This leads to decreased buttressing, acceleration of ice flow, and grounded ice loss. The ice loss occurs unevenly around Antarctic with over 70% of the.g.rounded ice loss occur ring in the eastern Amundsen Sea sector. As such, oceanographic observations were frequent ly conducted in this sector over the past decade. These observations have provided a sufficient amount of data to help develop a reliable ocean simulation that is able to simulate the current hydrographic conditions and past observations. This research focuses on the develop ment of a reliable ocean model, as only by using reliable model outputs we are able to investi gate the causes of the observed changes and sensitivity to climate variations. In this study, important physical processes governing ice shelf ocean interaction are explained including (1) the on-shelf intrusion of modified Circumpolar Deep Water, (2) oceanographic processes at an ice shelf interface, and (3) spreading and outflow of glacial meltwater. Additionally, we will present our model development, including model-data evaluation and development of ocean state estimates.