Optical inspection laboratory for coral reefs in Bermuda

The Coral Reef Ecology and Optics Laboratory (CREOL) uses Onset's water temperature logger U22-001 to monitor changes in seawater temperature around coral reefs in Bermuda.

Can you describe what you and your colleagues are doing to study BIOS and coral reef health working at the Bermuda Institute of Marine Science?

The Coral Reef Ecological Optics Laboratory (CREOL) conducts applied and basic research to understand coral reef ecosystem function and responses to natural and anthropogenic forcings. Combining traditional and more novel high-tech methods in the laboratory to address different aspects of coral reef ecosystems, including: diver-based surveys to assess benthic and fish communities; measurements of seawater chemistry to describe the environment Among them, coral reef habitats; remote sensing, to assess coral reef biomes; and optics, an effort to study how light is used to understand ecosystem function. The applied research component of Luzon is the Marine Environment Program (MEP). MEP is funded annually by the Bermuda Islands Government of the Department of Environmental Protection to help achieve the Department's mission to protect Bermuda's environment by conducting routine monitoring of marine resources. The goals of the MEP baseline are to: provide long-term data sets to assess the health of the marine environment; detect changes in the marine environment; understand the significance of existing pollution sources; identify new potential pollution sources; reveal the impact of local and regional (climate) stresses .

What does water temperature monitoring do?

Water temperature is one of the key environmental variables in coral reef environments. On a fine scale, the temperature of water directly affects biological and chemical reactions. On a wider scale, water temperature has been recognized as one of the main factors controlling the distribution of coral reefs. Bermuda is a coral reef system in the northern Atlantic Ocean.

Where do you deploy temperature logger U22-001?

The Sea Temperature Monitoring Program (STMP) includes 11 sites on the Bermuda platform, covering reef areas of varying terrain. Monitoring site selection to complement ecological assessments of the status and trends of benthic communities. This includes beaches such as Castle Peak Harbour, John Smith Bay, and Long Bay.

Can you describe your logger deployment method?

Generally, I use HOBO U22-001 water temperature loggers for field data collection at reef sites. Before deployment, all records are calibrated and tested for their health, such as battery life and connectivity. A pair of U22-001 water temperature loggers is being deployed on site (redundant) with a sampling regime set every 30 minutes. Ultimately we are interested in the maximum, minimum and average daily temperature. Once logged in, the U22-001 water temperature logger is housed in protective boots by the onset and hat. As deployed over a period of approximately 12 months, the U22-001 water temperature logger was attached with electrical tape to prevent scale, but ensure the sensor was still uncovered. Over the years, I've found it to be a time saver and a logger that enhances work life. I find it helpful to use small strips of matching colored tape for each pair of loggers. This allows for easy identification during deployment.

All logger connecting rebar stakes have been secured and secured to the reef with stainless steel hoops and cable ties.

Why did you choose the larger Onset U22-001 water temperature logger?

We like the size of the U22-001 water temperature loggers because they are large enough to see that U22-001 water temperature loggers are still at risk without physical evidence being next to them. We also found them easy to handle during deployment.

What are some of the challenges you face with respect to deploying loggers and/or retrieving data?

It doesn't have to be a major challenge, but damselfish can be a problem. We found that they have a tendency to make the stake/Recorder combination the center of their territory. High terrain means dealing with very excited fish to retrieve time!

What is a typical sampling rate for the type of data you collect?

For 12 deployments, we use 30 minute intervals. However, in the case of experiments, it can be used as finer scale as 5 s intervals.

How often is data offloaded and analyzed?

It depends on the project, but STMP is annual; experiments can range from hours to days. Later this year, I plan to use a data logger attached to a mooring line to give a temperature profile at a set depth. These will be analyzed daily.

What were some of the key findings in the data you collected from the U22-001 water temperature logger?

Coral bleaching events have been documented in Bermuda. In predicting climate change in terms of increased sea temperature, possible recurrence of coral bleaching events, and increased prevalence of disease, the U22-001 network of water temperature loggers provides us with a deeper understanding of temporal and spatial sea temperature trends around Bermuda's platform. In addition to developing long-term time-series records of ambient temperature records for coral reefs, we are able to identify meteorological events. Loggers were able to detect rapid and significant drops in water temperature (2º4°C) and cooling of sea surface temperatures caused by hurricanes and tropical storms. Second, the logger recorded a significant cooling (5º7°C), which is thought to be due to the upwelling of deep ocean water, possibly via internal waves.