A set of four evenly cut sections of PVC pipe filled with sand and connected by plastic joints, held together with epoxy, make the frame of a one-meter transect – a sampling tool commonly used by scientists in the field.
This transect frame needs to sink in water so the invertebrates team can sift through an area of sand for samples. Chris Appleton, invertebrate team leader, has a metal sieve attached to the end of a pole to scoop the sand on the banks of the Okavango River.
"It's quite difficult to sample here with the river moving so swiftly," he said. "In this deep channel, the habitat is unstable, a difficult place for bivalves to live." After conducting seven transects off a sandy bank, just upstream from camp, Chris found only four small clams, all the same species – Coelatura kunenenis. In other parts of the Delta, he's found some 40-50 individuals of multiple species. The only other organisms in the sand were gomphid, sand-burrowing dragonfly larvae.
Nets and Poles
|Tumie Mothibi, University of Botswana |
checks her scoop net.
"I almost had a leech," said Leeanne Alonso, director of CI's Rapid Assessment Program and invertebrate team member. "Except it wasn't in my net – it was on my leg!"
ARTICLE: Leeanne Alonso describes interesting things about small things.
In freshwater systems, scientists really have to "dive into" their sampling work. While Leeanne uses a fine mesh canvas net attached to a pole to sample for mayflies, beetles, shrimp and bloodworms (among many other species), she's often knee-deep in the watery banks of grass and papyrus.
Once there's organic matter in the net, she dumps the contents into a white tub slightly filled with water. Tumie Mothibi, a student from the University of Botswana, uses forceps to try to catch the swimming organisms, then puts them in a sample jar. It's essential to keep some creatures separate from others, since predators will eat the other species. In the end, the invertebrate team manages to capture a leech off the leg of a fellow AquaRAP team member sampling in the same site.
– Reported by Lani Asato
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