Scientific Diving Sampling Techniques

1. Scientific Diving Sampling Techniques

2. Sources • Heine, J. N. 1999. Scientific Diving Techniques. Best Publishing Company, Flagstaff, Arizona. • Norton, S. 2000. Lecture - Diving in Biological Research.

3. History of Scientific Diving • 1953 – scuba diving in support of science authorized at the University of California. First in U.S. • 1956 – research conducted using scuba first published • Aleem, Anwar Abdel, Quantitative underwater study of benthic communitiesinhabiting kelp beds off California. (1956) Science. 123(3188)1956:

4. Coral reefs Mangroves Kelp forests Rocky shores Soft bottom habitats Polar environments Open ocean/blue water environments Offshore platforms Estuaries Hot springs Hypersaline environments Caves Lakes Rivers Scientific diving has been conducted in a wide variety of environments…

5. …and been used in many different sciences • Chemical • Geological • Biological • Paleontological • Archaeological

6. Chemistry – diving has been used to support research such as determining the chemical ecology of invertebrates and collecting marine organisms for the extraction of chemical compounds.

7. Geology – divers may obtain core samples of rock and sediment… …or dig holes to examine depositional history Scuba is very useful for visual identification of sediments – and for collecting representative and relatively undisturbed samples

8. Biology – Divers may perform a wide variety of tasks such as measuring various community structural parameters like fish density, algal density, macroinvertebrate density, percent cover of benthic algae and invertebrates, etc…, or measuring physiological responses of organisms in natural environments.

9. Paleontology – divers recover fossils from the underwater realm… Dinosaur fossils from the waters off the Isle of Wight

10. Of course, diving is integral to the study of underwater archaeology… Excavation of 4th – 6th century A.D. harbor site in Malta. Serçe Limanl excavation – Diver raises fragile hull timber using a lifting box. Serçe Liman1 excavation - 11th Century Byzantine Shipwreck - Diver hovers above grid used to mark locations of artifacts

11. Scientific Diving - General • The diversity of disciplines involved in scientific diving, and the varied environments where this diving is performed, has necessitated the development of a wide variety of techniques for observing and sampling underwater.

12. Recording Information - Slates • Almost every scientific project requires that data be recorded underwater. Slates are a simple tool for doing this. • The best material for a slate is a white polycarbonate or acrylic. This material is strong, waterproof, and negatively buoyant. It will not corrode when exposed to salt water, and is available in sheets, which can be easily cut to the desired size.

13. Diver using slate to record organisms found in artificial reef

14. Recording Information - Slates • Slate size and form may vary - large or small, single or multiple sheets, flat or curved to fit around the wrist.

15. Recording Information - Slates • For archaeology, it is recommended that the minimum dimensions of a slate should measure approximately 10” x 12” x ¼”, to 12” x 14” x ¼”. Much smaller and the diver has inadequate space for detailed recording. Larger slates are useful, but can be difficult to handle under certain conditions.

16. Recording Information - Slates • A wooden or mechanical pencil is attached to the slate by a string, cord, or rubber tubing. Bic brand mechanical pencils have been found to work the best due to the hardness of the lead, but the mechanics of the pencil are not always reliable when repeatedly exposed to water. Regardless of the pencil chosen, always carry at least one spare. • A pencil may be used to write directly on the plastic of a slate, or to write on material attached to a slate.

17. Recording Information - Slates • Mylar is often attached to slates and drawn on underwater. It is a thin plastic film (or sheet) frosted on one or both sides. Mistakes are easily erased using a standard eraser. Mylar is available from drafting supply stores in rolls, which are easily cut to size with scissors or a paper cutter. Since drawing is done on the frosted side, double frosted Mylar alleviates the problem of which side to draw on. The Mylar sheet is secured to the slate using strips of Duct Tape. It is important that the sheet is secured properly so that several hours/days work is not lost by having the sheet come off underwater

18. Locating, Relocating, and Marking Sites • Locating, relocating, and adequately marking a study site are critical. Many methods may be employed. • Compass bearings • Use compass bearings towards readily identifiable objects on land • For greater accuracy, use shore lineups, where pairs of objects that are in a straight line can be used to triangulate a position. • Disadvantage – shore markers may not always be visible

19. Locating, Relocating, and Marking Sites • Global Positioning Units (GPS) • Relatively inexpensive, portable, and accurate • Can store multiple points (waypoints), give the heading, distance, time to each waypoint from your present position and store multiple routes with many legs on each route • Sonar (depth finders) • Tell water depth, or distance underwater to structures

20. Locating, Relocating, and Marking Sites • Buoys • Perhaps the best and easiest method for relocating a site from the surface • May be inexpensively made from plastic bottles • Torpedo shaped buoys minimize chances of entanglement with kelp • May be connected to the bottom with chain, cable, or lines • May be tied to structure on bottom – length of garden hose may help to avoid chafing – or weighted on bottom • In sandy or soft-bottom areas, sand, earth, or fence anchors can be screwed into the bottom • Disadvantages – take time to install correctly, and are subject to loss from storms, theft, entanglement in boat propellers, or mauling by marine animals.

21. Locating, Relocating, and Marking Sites • Underwater marking – may be necessary once the surface location of a site is established. • Variety of items may be driven into the substrate • Nails • Tent stakes • Rebar • Railroad spikes • Pitons • Marking tags may be placed on these • Cable ties • Vinyl roll flagging tape • Pieces of PVC

22. Locating, Relocating, and Marking Sites • To properly mark an area, it may be necessary to drill holes • Star Drill – hammered in by hand. The drill is held with pliers and is rotated slightly with each blow of the hammer. • Time consuming and tiring. Not practical if large number of holes must be drilled.

23. Locating, Relocating, and Marking Sites • Pneumatic drill or hammer – good for making numerous holes, especially in hard rock - or for more permanent fastening. • May be fitted to work off a scuba tank • Disadvantages: • May use a great deal of air • Very loud • Require considerable maintenance after use • Hydraulic systems • Advantages - Quieter and more efficient than pneumatic tools • Disadvantages – More expensive – requires a link with control station on surface

24. Locating, Relocating, and Marking Sites • Cement and epoxy may also be used to adhere items to the substrate. • Generally work best on a clean substrate • May be packed into cracks, crevasses, or drilled holes • Marine putties or underwater patching compounds have been used • A mixture of four parts Type II Portland cement and one part molding plaster combined with seawater may be carried underwater in plastic bags. This mixture can be packed into holes before placement of eyebolts or stakes.

25. Geological Measurements and collections • Collection of sediments - Coring devices – useful for stratigraphy determination or grain size analysis. A wide variety of corers are available. • Coffee can with plastic lid • Remove bottom and replace with fine mesh screen. Insert corer into substrate and push lid under lip of corer to seal it before removing. • Very inexpensive • Piston corer • May be constructed from PVC, designed to collect a complete and undisturbed sample

26. Geological Measurements and collections • Small Ekman grabs and box corers May be manually inserted and tripped by divers, insuring proper and complete samples are collected.

27. Geological Measurements and collections Box corers may be fitted with a slide hammer for driving into the sediment. Some corers also have sliding doors – grooves along the open side of the corer guide the removable door down the open face once the corer is in place in the sediment. This eliminates the need to excavate and expose the lower surface of the corer to install a lower plate before removing a sample from the sediment. Sliding door Slide hammer Box corer filled with sediment

28. Geological Measurements and collections • Vibrocoring (vibracoring) – collecting cores of unconsolidated material by driving a tube with a vibrating device (vibrohead). • 3 types of vibrators: • Pneumatic • Hydraulic • Electric

29. Pneumatic vibrocorers – can be made to work underwater with very few adjustments and don’t involve the use of electrical current. They work best in relatively shallow water because of increased air consumption at depth. They also require a cumbersome compressor, and the hose becomes an impediment in swift or choppy waters. Hydraulic vibrocorers – Do not share depth limitations with pneumatic corers, but do require a hydraulic power plant and an umbilical hose. Hydraulic corer Electric vibracorers – are more efficient (have a better force/weight ratio) than other types, and do not require umbilical hoses or large compressors or power plants.

30. Geological Measurements and collections • Heavy cores may be brought to the surface with lift bags

31. Measuring Temperature • Hand held thermometer • Generally encased in stainless steel or plastic • Temperature data loggers • Long term • May be downloaded to computer after retrieval or in situ. • Fouling organisms may be issue – users often wrap download connection points with tape or encase thermometer in PVC

32. Multiparameter instruments • Conductivity, Temperature, and Depth units (CTD’s) • May measure other parameters such as salinity, fluorescence, pH, turbidity and oxygen and may take water samples from different depths • May be small enough for divers to swim with them underwater to collect discreet data from precise locations.

33. A NOAA CDT

34. Measuring water motion • May be difficult and complex to measure • Plaster • Blocks of plaster are weighed, affixed to some sort of framework and deployed. The plaster dissolves in water – faster or slower depending on water velocity. After recovery, the plaster is dried and weighed again. Differences in weight give a relative measure of water motion. Plaster attached to cards (referred to as “Clod cards”). The one on the left has not been deployed – the other two have. Note the size difference

35. Measuring water motion • Fluorescent dye • useful for determining current direction and velocity - may be released and visually tracked and timed, or recorded on a video camera with a timer.

36. Measuring water motion • Current meters • Small hand-held flow meters • Different rotor size for different water velocity ranges

37. Measuring water motion • Current meters may also be attached: • Taut- line mooring – current meter is attached to a line that is weighted, anchored, or fixed to a sand anchor in soft sediment • Under a strong current, however, the meter will be deflected • Rigid mooring – will prevent deflection of current meter • Inexpensive option: concrete block with four out-riggers for stability, and a vertical pole with a swivel on top for the current meter

38. Rigidly moored current meter on tripod.

39. Measuring Light • A variety of light meters are available. • Divers may use hand held light meters for measuring light in precise locations • Light meters may also be deployed for long periods of time in specific locations Light meter

40. Diver uses handheld light meter to determine level of light reflected from coral

41. Sound • Measuring sound underwater often requires the deployment by divers of transducers (for transmitting sound) and hydrophones (for listening to sound emitted from both biological and physical sources) – these are sometimes quite large

42. Diver deploying transducer Biologist using video and hydrophone to record fish sounds

43. Chemical measurements • May range from simply collecting water in a plastic container to using sophisticated collection techniques and analyzing devices…

44. Van Dorn Bottle –May be mounted on scuba cylinders and tripped by diver at precise time and location to collect discreet water sample for analysis. Sediment oxygen demand chamber – may be positioned by divers at specific locations – used to measure sediment oxygen demand.

45. Underwater Archaeology • Underwater archeologists locate, draw, excavate, and recover material objects in order to better understand history and culture. Divers are integral to this process.

46. Archaeologyand Low Visibility • Because many sites of archeological interest are located in coastal environments, estuaries, or rivers, a great deal of underwater archaeology takes place in locations with poor water visibility. Frank Cantelas dredging during 1992 Maple Leaf expedition.

47. Low Visibility - Measuring • Clear ziplock plastic bags (“Brody Bags”) filled with water may be used to view measuring tapes in low visibility situations. The bag is placed on the tape and a flashlight is used for illumination. • The bag may be made more secure by applying duct tape to the sealed portion of the bag. • Before recording measurements, it is always a good idea to have a diver swim the tape to ensure it is not snagged somewhere.

48. Archaeology – Mapping • Mapping is how locations are recorded in two or three dimensions. This is done by taking measurements. • Site maps are two dimensional plan views looking down from above, using an X and Y coordinate system. • The third dimension, or Z coordinate, provides depth or elevation data. Profile views use the Z coordinate to record cross sections that show the vertical components of a site. A 2-dimensional and 3-dimensional coordinate system

49. Archaeology – Mapping • Establish a number of fixed points (datums) across the site – measurements are taken from these datums which are used as reference points. An intact wreck may have only 2 datums – bow and stern • Datums: • Must not move • Must be precisely located (if using more than one datum, and you usually are, they must be precisely located in reference to each other in order for your site map to be accurate) • Datums should be high enough not to be obstructed when taking measurements.

50. Archaeology – Mapping • Fix a baseline (usually a tape or line marked in regular increments) between datums. Baselines allow three things to be done: • 1) Mapping of features that fall under the baseline • 2) Making measurements away from the baseline • 3) Creating a mapping grid over the site. 1) 2) 3)