Scientific diving at work can be described as any diving operation undertaken in support of science. Because of this, the tasks undertaken under the scientific code can vary markedly. Below are some examples of diving projects that are typical of those supported through Scientific Diving.
|
|
Underwater photography Photography can be used underwater in order to better illustrate an event or process or for more detailed analysis. Traditionally most underwater photography was by film SLR cameras. Increasingly this is being replaced by high resolution underwater digital SLR still photography. |
|
|
Specimen collection or in-situ measurement
Using divers to collect biological specimens from the underwater environment has many advantages over surface-based collection methods. The use of divers over trawls or grabs is that they are not destructive and also only take the minimum number of specimens required. More advanced collection techniques, such as the use of anaesthetics underwater, allow specimens to be captured, measured, sometimes tagged, and replaced to the exact location of capture. In a similar way, the measurement of some plants and animals can be made in-situ underwater without the need to destroy them through retrieval to the surface. Examples of studies that have employed advanced specimen collection techniques underwater are:
|
|
|
Static underwater video The presence of divers underwater can disturb or interrupt natural events. In order to construct longer term analyses of events, static underwater video equipment is deployed. The equipment can either store the images self-contained or transmits the images to the surface through umbilicals. The use of time-lapse can prolong the operation; infra-red cameras can record both at night and day. Correct positioning of the cameras by divers is often an essential component of the study. Divers can also maintain the equipment underwater meaning that the apparatus does not have to be come to the surface each time. Examples of studies that have employed diver-deployed static underwater video are:
|
|
|
Underwater survey Diver-based underwater surveys are often used to quantify biological communities or single species over defined areas. There are advantages and disadvantages to using divers for survey work, and there are many different forms and approaches to conducting the surveys. Examples of studies that have employed diver-based survey for data collection are:
|
|
|
Video mosaicing
It is often very difficult to obtain broad scale visualisations of areas of sea bed. If the water is dark then a lot of illumination is required. In the UK, waters are often turbid and so obtaining a broadscale photograph is almost impossible. Video mosaicing employs digital video cameras on a sliding apparatus constructed underwater to maintain attitude and height above the seabed. The camera is moved over the area to be visualised and either continual or individual images taken. The processing of the images takes a percentage of each image and digitally overlays it onto to the previous image. Even though the resolution of a single frame of video footage may not be high, once fully mosaiced, the researcher will obtain a high resolution image of a wide area, irrespective of the water clarity or lighting. An example of a study that has mosaiced video images obtained by divers is:
|
|
|
Benthic coring Benthic cores contain a lot of information about the receiving environment and the impacts on it. Sometimes the cores are taken for pollutant analysis, sometimes to assess the bioligcal community within the benthos, and at other times in order to make physico-chemical measurements on the cores post-collection. The advantages of using divers to core by hand is that they can be precise on where the cores are taken from and the level of disturbance is less than if some form of surface deployed corer was used. Example of studies that employed benthic coring using divers are:
|
 |
Coral coring The longevity of coral reef development and the processes that go into that development make coral reefs ideal sources for proxy studies of the long-term climatic record. The length of core is correlated to the time record and analysis of changes within the core can determine indirectly the climatic conditions at that point. Divers are used to drill into coral heads in order to minimise disturbance and guarantee the quality of the core. An example of a study that employed coral cores obtained by divers is:
|
 |
Equipment deployment and maintenance Often divers are employed in support of science simply to deploy, maintain and/or retrieve monitoring equipment underwater. By attaching the equipment to permanent or long-term moorings using divers means that the whole mooring does not have to be lifted each time. If a large surface vessel is required for this lifting process then it can be expensive. Continual deployment and recovery of moorings can impact the sea floor in vulnerable areas. The example shown is deploying an underwater hydrophone for detecting Harbour Porpoise movements. Other examples are tide gauges (e.g. www.pol.ac.uk/ntslf ), temperature loggers, sediment traps, current meters, settling panels and a whole range of specific underwater experiments.
|
