Collecting data
When undertaking scientific research, there is always some paperwork to begin with. Researching and finding out as much background information as possible is a great place to begin and may help you find an area you want to know more about. This will help you to ask the right questions.
Imagine you are heading to a rocky shore and on the spur of the moment decide to conduct an experiment. You decide that you will undertake a population study of the sea squirt (cunjevoi). You get to the rocky shore, the tide is high and it is a beautiful day but you find no sign of any sea squirts. You conclude that there are no sea squirts in Tasmania. If you had of done some background research you may have discovered that sea squirts are usually only seen when the tide is low as they live in the low-tide zone, or lower mid littorial zone. Therefore, you should have sampled during low tide!
The scientific method
Initial studies of a new region may have an investigative objective or aim – to describe what species are present at a specific location or how species change over time. This information will provide background for more intensive studies or specific questions and be can used to develop a hypothesis.
Once you have a topic of interest it is usual for a scientist to develop a scientific hypothesis that will be tested. This hypothesis is not a question but a statement of what the scientist thinks he or she may find. The data gathered will either support or disprove this hypothesis.
For example, your aim might be to find out about sea squirts so you will ask “where would sea squirts be found on the rocky shore zone of my favourite beach?” After a little background research, showing you that sea squirts need almost continuous access to water, you may hypothesise that “Sea squirts will be most abundant on the rocky shores when the tide is low”.
Now you head out to your intertidal zone and try to find evidence that supports your hypothesis. This is the bit where science gets all tricky – you can never prove that your hypothesis is absolutely 100 per cent correct because you are not looking at every rocky shore in the whole wide world. So you will either find evidence that supports (but not proves) your hypothesis or you will reject your hypothesis.
Importantly, the greatest strength of the scientific method is the fact that even a single negative study can disprove your hypothesis. This enables continual improvement in our understanding of the world as inaccurate ideas are refined and improved or discarded.
Will one transect do?
If you went for a swim in the ocean and were lucky enough not to see a shark that day, would you assume there were no sharks in the ocean? Chances are you know better. Science relies on the collection of information or “data” over time. This has helped scientists build up an inventory of species that inhabit Tasmanian oceans. By repeating surveys using similar methods again and again, a list of known marine life can be created, added to and reviewed. So no, one transect will not do.
Sampling methods vary greatly and how you collect information or data during your survey will differ, depending on what your hypothesis or aim is. As there are a variety of sampling methods you will have to choose the one best suited to your question.
There are different ways to collect data and technology is changing so quickly that new techniques are always being developed. Studies of particular species may tag or satellite-track individual species within a population. Studies describing or measuring different types of habitats may be mapped at different scales using computerised data, aerial photography or sonar technology from satellites in space, just to name a few.
Meet Drs Rick and Jemina Stuart-Smith. They are marine biologists who work on a project called Reef Life Survey. This project collects marine species data through dive surveys of reef environments. The data is collected on the website which aims to provide an extensive species list of areas around Tasmania and the world, and to monitor how these change over time.
It is not possible for Rick and Jemina to count all the fish in the sea. The ocean is incredibly large and has a diverse range of life, much of it moving about constantly. Rick and Jemina break up a large area into smaller areas. These smaller areas are surveyed using transects and quadrats (see below), these are then are used to represent the whole area.
Transect: sampling a profile of an area along a line. Transects are useful as they show changes in marine communities as you move along the line. From this, we not only know which species are there, but can use the information to estimatethe density of each species.
Quadrat: sampling inside a designated area (usually a square) of a predetermined size depending on the sizes of the species or habitat you are sampling.
Scientists usually look for or examine patterns and trends in their data using maths and statistics. Statistics may be used to help determine how accurate the information you are collecting is and things like whether changes are occurring over time; statistics can be a bit complicated and we might leave that for maths class!
Rick collecting data on a rocky reef using a transect (white tape in foreground. Image: R.Stuart-Smith)
To see a video of the Reeflife Survey team undertaking field work go to http://www.youtube.com/watch?v=9MqsxjnH-Lk
Good observation skills are vital for scientists test yours on our sea shell observation worksheet.
Acknowledgments:
Thanks to Rick and Jemina Stuart-Smith and David Brown for their input into the Little Bit of Science section for explaining the scientific method and sampling techniques used by Reeflife Survey.
