Coral bleaching is an ecological response to stressful physical conditions observed to occur when strong insolation coupled with stratification of the water column leads to anomalous warming of the surface water. Stratfication requires calm winds, the absence of waves, and an absence of currents: conditions which result in limited mixing of the water column and thus confine heat due to insolation at the ocean surface. There is a strong need to identify which of the physical parameters are more significant at any given time and, more importantly, to monitor the physical parameters in near realtime to serve as a tool for long-term planning and management for marine parks and coastal waters. This paper reviews the contribution that currents make to mixing in the water column through the dissipation of turbulent kinetic energy and takes a further step to evaluate the use of surface current data to provide an index of vertical mixing. In this work, when the surface current speed is greater than a critical value, the water column is found to be vertically mixed even in the absence of wind or waves. A phased array HF Ocean Radar deployed in the southern part of the Great Barrier Reef provides a map of surface currents with high spatial resolution (4km) every 10 minutes over the grid. These surface currents are used to predict vertical stratification and mixing which can then be used as an indication for conditions under which bleaching might occur.

No abstract

No abstract

No abstract

The engineering programs at our university are designed to achieve student learning outcomes in maritime engineering knowledge and hands-on experience imposed by the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers. After completing the topic of electronics, students are expected to (1) understand the characteristics of basic electronic circuit elements, (2) configure and operate principles of electronic equipment, and (3) interpret electrical and simple electronic diagrams.Recently, an automatic compartment temperature control project was designed and added in the Electronics Laboratory course to evaluate student learning outcomes in electronics. Different from previous isolated lab experiments, the new project requires students to integrate multiple experiments to design and build complex integrated circuits to solve a practical problem. Students first designed multiple electronic circuit modules to separately implement temperature measurement, temperature comparison and actuator control and then integrated all electronic circuit modules as complete electronic diagrams. Second, they used electronic circuit elements in lab to build integrated circuits on breadboards according to the complete electronic diagrams. Further, they tested the integrated circuits on breadboards to observe whether the integrated circuits can activate or deactivate an actuator in response to temperature change. They could use electronic equipment, such as multimeter, oscilloscope, etc, to diagnose the integrated circuits if necessary.After the completion of the project, all students' integrated circuits were assessed by the instructor on whether they can measure indoor temperature, compare it with the desired temperature and invoke actuator control to automatically maintain indoor temperature. Additionally, an optional student questionnaire survey was conducted among the students who were participating in the project to assess student learning outcomes. The assessment results show a strong positive effectiveness of the project on understanding, configuration, operation and interpretation of electronics. Student narratives also imply the project led to interest and fun of electronics to them.