Picking bugs with friends

Today some of our friends from the Mara came to the river with us to help out with our work and see what we're up to. Here are Nick, Julia and Wes picking aquatic insects out of a net and off of stones by the river.

Frank Masese and the Aquatic Insects of the Mara

We were really excited to have one of our friends and colleagues visit us for a few days in the field this past week. Frank Masese is an aquatic ecologist currently pursuing his PhD at UNESCO-IHE Institute for Water Education in The Netherlands. Frank is interested in organic matter inputs into the river, how they are processed by the river and its food web, and how these processes are altered by land use change. There are a lot of connections between his research and mine, and he's been a great colleague to have in the basin. He also knows a tremendous amount about aquatic macroinvertebrates, among many other things, so we took the opportunity of his visit to learn a lot from him about some of the critters we've been catching in the river of late.

The way we sample for bugs in the river is by using a kicknet. We hold the net in place in the river while we kick the river bottom upstream of the net, dislodging small insects that then float into the net.

Checking out our catch

 After you get the bugs in the net, you have to sort through a lot of other plant debris, sand, etc. to find and pick out the bugs.

Frank examining the net for bugs

 The bugs can be really small, and there's often a lot of dirt in the net, making this a pretty meticulous process.

Picking bugs out of the net

 The reward of all this sampling is a living story about the state of the river. Aquatic insects are important to the functioning of the river through breakdown of organic material and providing prey for larger animals. They also are great indicators of the river's health, because they are affected by physical and chemical changes in the water, they can't easily escape large changes, and different groups of insects are more or less sensitive to water quality. Just by looking at who is living in the river, you can learn a lot about how the water quality has been over the last few weeks.

Here are some mayflies we caught from the family Beatidae. Mayflies, in the order Ephemeroptera, are fairly sensitive to water quality. Baetidae are collector-gatherers that feed on plant detritus in the river. This is probably the most common family we catch, although there are many different species included in the family. In this picture, there are two different species of the same family.

Ephemeroptera Baetidae

Here are some mayflies we caught from the family Tricorythidae, which are also collector-gatherers.

Ephemeroptera Tricorythidae

This is another example of a mayfly, from the family Centroptiloides, but these guys are predators.

Ephemeroptera Centroptiloides

We also found a few of these beautiful stoneflies, from the order Plecoptera, which are also highly sensitive to water quality. This individual is from the family Perlidae, and it is a collector-gatherer like the Baetidae and Tricorythidae.

Plecoptera Perlidae

 The third order known for being especially sensitive to water quality is Trichoptera, or the caddis-flies. Ephemeroptera, Plecoptera and Trichoptera are so well-known for their sensitivity to water quality that there's an index of aquatic health known as the % EPT index, or the % of insects captured from those 3 families. Here is a Hydropsychidae, which are filter feeders in the river.

Trichoptera Hydropsychidae

 Finally, we also caught a larval dragonfly, from the order Odonata. Odonates are also sensitive to water quality, but not as much as the EPT taxa. This one is from the family Gomphidae, and it is a predator.

Odonata Gomphidae

 It's a great sign about the river's health that we are catching so many sensitive species in the river this season. In fact, we are seeing some sensitive species at sites that we don't remember seeing before. I think the healthy flow levels over the past year have been great for the overall health of the river. Thanks so much to Frank for teaching us more about these river dwellers!

Scenery

Sometimes we get a bit numb to the amazing scenery we drive through every day, but then you happen upon a scene like this, and it just stops you in your tracks...

Giraffes relaxing in the savanna

Leaving Narok

Two days after we were supposed to leave Narok, we finally hit the road. Celebrated with a cappuccino and cheeseburger on the way out of town.

What do carcasses do to a river?

Carcasses contribute a lot of nutrients and carbon to a river system. Depending on the nutrient and carbon levels already in the river, these inputs can either cause an increase in primary production, like algae, or an increase in respiration, caused by bacterial decomposition. Although there are a relatively small number of carcasses left in the river, the river flows have also started going down over the last two weeks, making the effect of the carcasses more noticeable. We have found that most of the equipment we have in the river now has pieces of rotting meat and hair hanging off of it. Here are some tiles we place in the river to measure the growth of biofilm. Biofilm is the community of algae and bacteria that grows on the rocks and sand in the river-- this is what makes river stones slippery. You can see here a big piece of meat hanging off the tiles, and likely affecting what's growing on them.

Carcass meat hanging off my experiment

After we pull the tiles out of the river, we put them in sealed containers of water, and measure the dissolved oxygen in the water before and after exposing the tiles to sunlight and darkness. If there is a lot of algae, they will undergo photosynthesis in sunlight and produce oxygen, resulting in an increase in dissolved oxygen levels. If there is a lot of bacteria, they will just undergo respiration during both light and dark and take up oxygen, resulting in a decrease.

Measuring biofilm activity on carcasses

This is one way we measure how the input of wildebeest carcasses in the river affects the other things living in the river. We also can look directly at the carcasses to see what's eating them. Investigating a few carcasses up close, we found they had lots of a certain kind of aquatic insect called Baetidae (which is a type of mayfly) hanging out on them. By collecting the insects and measuring their stable isotope composition in the lab, we can learn if they are actually eating the carcasses as well as living on them.

Mayfly larvae on a wildebeest carcass

Tough 2.0

Camera trap case for use in the Masai Mara...with a secure locking box for an external battery for extended deployment.

Wet parts

Still at the garage. I've clocked in about 20 hours here over the last 2 and 1/2 days. Still trying to find the source of the rumbling noise. Replaced and inspected countless parts and still can't find it. Now we're back to the transfer case. Time to open it up...again. But...we can't till the rain stops.

River of bones

On Nov. 13, what will likely be the final die-off of the season occurred. Most of the wildebeest herd has now returned to Tanzania, but a small group crossed at a place downstream of where most of the drownings have occurred, and about 220 drowned. We took these pictures about a week and a half after the drowning had occurred, and most of the carcasses have already broken down a good bit, leaving the river scattered with bones.

Wildebeest bones in the Mara

Thanksgiving Day Feast(s)

One of the hard things about working internationally is that you miss spending big holidays with family and friends back home. Fortunately, we have a great group of friends here in Kenya, and we were able to spend an awesome Thanksgiving holiday celebrating with them. And what's better than one Thanksgiving celebration? Two!

We wanted to thank the team of builders and engineers who are helping install the equipment at the bridge for our water meter, as well as all the Mara Conservancy rangers and staff who help us with our work all the time, so the night before Thanksgiving, we had a traditional Kenyan goat roast with them. We bought a large goat from one of our friends, packed him up in the Land Rover and drove down to the bridge.

Thanksgiving goat

Goat in the Land Rover - awesome!

  While we worked in the river, several of the guys did all the slaughtering and preparing, and by the time we got back to camp, the goat was already cooking on the fire.

Cooking goat over the fire

We set up our camp at the Rangers' Station for the night, and enjoyed a wonderful meal of goat meat and ugali with good friends. It was a perfect way to start the Thanksgiving holiday!

At camp with Warden Konchella

Celebrating with friends

The next morning, we headed back to Maji Camp (our home base) for a traditional American Thanksgiving meal. All the Americans around (us, the hyena researchers, and the hot air balloon pilot) and several Kenyan friends and colleagues sat down to share an amazing potluck meal, complete with roast turkey, gravy, mashed potatoes, dressing, cranberry sauce and brownies. It was an incredible taste of home and lots of fun.

Dinner table panorama

Even though we were far from home, we felt very blessed to share this holiday with so many good friends.

Thanksgiving dinner in the Masai Mara

Small Work Turned Big

As I'm sure you can tell...I'm spending lots of time at the garage today.

Now we're putting back together the transfer case.