The global threat to marine ecosystems due to over‐exploitation, habitat loss, pollution and climate change is exacerbated by introduction of alien species, which is considered to be one of the leading causes of extinctions and biodiversity loss.
Scientific divers are the most competent to detect the presence of potentially invasive species and in some cases can provide a quick response.
Training standards vary throughout the world, and are generally higher than for entry level recreational diving, and in some cases identical to commercial diver training.
There are a few international agreements that facilitate scientists from different places working together on projects of common interest, by recognising mutually acceptable minimum levels of competence.
In situ assessments by scientific divers remain the most flexible tool for exploring this habitat and allow precise and optimised location of instruments.
The capacity to dive under polar ice provides an opportunity to advance science in a restricted environment at relatively low cost.Scientific diving is any diving undertaken in the support of science, so activities are widely varied and may include visual counts and measurements of organisms in situ, collection of samples, surveys, photography, videography, video mosaicing, benthic coring, coral coring, placement, maintenance and retrieval of scientific equipment.Underwater diving interventions, particularly on scuba, provide the capacity for scientists to make direct observations on site and in real time, which allow for ground-truthing of larger scale observations and occasional serendipitous observations outside the planned experiment.Monitoring the effectiveness of response also requires diver intervention.Scientific diving may use any mode of diving that is best suited to the project.Several citizen science projects use observational input from recreational divers to provide reliable data on presence and distribution of marine organisms.The ready availability of digital underwater cameras makes collection of such observations easy and the permanence of the record allows peer and expert review.A small number of holes in the ice can provide access over a large area and high levels of experimental replication.Divers are a flexible and reliable method for deploying, maintaining and retrieving equipment from under‐ice environments, and are relatively cost efficient for researching remote locations that, would otherwise require the use of more expensive research vessels.Open-circuit scuba is most often used as it is widely available and cost-effective, and is the entry level training mode in most places.Scientific diving in the course of employment may be regulated by occupational safety legislation, or may be exempted as self-regulated by a recognised body. Collection of scientific data by volunteers outside of employment is generally considered to legally be recreational diving.