Melaphis rhois is an aphid species known as the “Staghorn sumac aphid”. It is a type of woolly aphid and one of the few aphids that induce the formation of galls. The species produce galls on the Staghorn sumac (Rhus typhina) when female aphids lay a single egg on the underside of the sumac leaf, inducing the leaf to form a sac about the size of a golf ball over the egg.
Diatoms are interesting critters on many levels; one is their sensitivity to water pollution. I do not have the equipment to test the chemical composition of water but I have acquired a digital pH meter which is fine, because pH is pretty much the universal pollutant.
Diatoms can only thrive in water that has a limited range of pH; with each genus having its own range. In fact, it is said that one can determine the pH of water simply by noting the diatoms which can, or cannot, be found there.
My increased interest in diatoms will be well served by the acquisition of a pH meter since it will allow me to do real science in that area.
Virtually all diatoms have linear markings that run across the short diameter of the frustule, as in the image above. One of the more interesting diatoms I found in the early searches of the new pond water is the one below. Note that the lines run along the full length of the diatom, not the short sides. Although these markings are quite unique, I have yet to identify the genus.
Despite receiving seven inches of rain over the last three weeks, the local vernal pond had barely enough water to detect. The entire water table must be very low because even the nearby stream is well below its normal level. I gathered enough water and decomposing vegetation to replenish my small aquarium. I was hoping for a nice number and variety of diatoms; perhaps the low water level concentrated the micro-critters that were present. In any event, I was not disappointed.
Although it is often correctly said that protozoans can be found anywhere there is water, it doesn’t always work quite that way. For example: Protozoans can be found in damp moss. But you can search through a lot of moss before you find one. The statement “You can find protozoans in moss” is correct; but it isn’t always correct all of the time. That is why I was very pleased to find large protozoans (30 um and up) in considerable numbers in our birdbath.
Although this Actinophyrs is not the perfectly symmetrical organism that one usually associates with the Heliozoa – it is, non-the-less, a very interesting “Sun Animalcule” to encounter in a drop of “living water”. Especially in a lowly birdbath.
It has been about a year since I last explored the water in our birdbath and I probably shouldn’t have waited that long. It was obvious, even to the naked eye, that the water was full of green algae. And under the microscope both filamentous and spherical algae of various sizes dominated the view.
Not to belittle algae, but much more of interest could also be seen. But more about that in upcoming posts.
When Hiberating Microbes Awaken
It’s commonly known, at least among microbiologists, that microbes have an additional option to living or dying — dormancy. This ability to remain dormant for long periods of time is relevant to studies concerning the transfer of organisms from one planet to another, either by natural means or on spacecraft sent by humankind. Dormant microorganisms can also teach us about signatures that could identify past or present life on other planets, such as Mars.
Dormant microbes are less like zombies and more like hibernating bears. What isn’t known, however, is how large numbers of dormant microorganisms affect the natural environments when they act as microbial seed banks. In the current issue of Nature Reviews: Microbiology, Jay Lennon, Michigan State University assistant professor of microbiology and molecular genetics, examines the cellular mechanisms that allow microbes to hibernate and addresses the implications they can have on larger ecosystems such as soil, oceans, lakes and the human body.
“Only a tiny fraction is metabolically active at any given time,” said Lennon, who is affiliated with MSU’s Kellogg Biological Station and MSU’s AgBioResearch. “How would our environment be altered, in terms of carbon emissions, nutrient cycling and greenhouse gases such as nitrous oxide, by dramatic increases or decreases in the dormancy of microbes?”
Dormancy is a reversible state of low metabolic activity that organisms enter when they encounter hard times, such as freezing temperatures or starvation. Unlike plants that follow predictable growth cycles, microbes don’t have to follow a linear progression. They could be growing, experience distress and go back to sleep. Once conditions change, they could start growing again without having to go through a full cycle.
“However, it does take a certain level of commitment, a certain energy investment to make it happen,” Lennon said. “Just as people don’t run out and winterize their homes if it gets cool in August, microbes want to be sure that truly hard times have set in before shifting into a dormant phase.”
Consider that 90 percent of soil microorganisms are typically dormant and only half of bacterial species are active. Lennon and his co-author, Stuart Jones at the University of Notre Dame, theorize that dormancy and the presence of such large reservoirs of microbial “seed banks” have important implications for biodiversity and the stability and functioning of ecosystem services.
“The idea of a microbial seed bank is a rather novel concept, but from our research we found that dormancy and seed banks are prevalent in most ecosystems.” Lennon said. “What’s fascinating is that there’s only a small fraction that are active, which means there’s a large reservoir that could potentially be activated at any given time.”
Dormancy and the seed bank effect make microbes more resilient and could play key roles in microbial biodiversity as species migrate or simply remain mostly dormant over extended periods, he added. Dormancy could also help explain the sudden outbreak of diseases, he said, perhaps sparked by some change in the environment.
“One-third of world’s population carries dormant tuberculosis microbes,” he said. “Obviously, you can live a long time with the dormant cell in your body, but it’s important to understand what can trigger its reanimation or what maintains its dormancy.”
As Lennon continues his research, he is particularly interested in identifying the triggers of dormancy and activation cycles as well as how climate change affects these processes.
After a very long hiatus I finally returned to my study of the matrix that once surrounded the skeleton of a mastodon. I have now reached the point where I am searching with a microscope at very high magnification (400x).
One of the most intriguing micro-objects is the wing of an insect. Although it is impossible to know for sure, I estimate that the length of the entire insect to be in the 1/10 mm range. No venation is visible which may indicate that it is the wing of a wasp.
Nematodes are microscopic worms that can be found virtually anywhere there is water; even the very thin layer of water between minute pieces of soil. There is usually little to tell one type of nematode from another, but the stylet in the head region (see inset) shows that this is a Root Lesion Nematode – the stylet being used to extract nutrients from the roots of various plants.
Identification was also helped by the fact that this is a very common type of nematode. It was found in a clump of moss in my backyard.
The pond water from Powdermill contained little variety in its micro-critters. Possibly because I could only get a pint of water and a little vegetation from very near the surface. Had I been able to reach the bottom of the pond I feel sure that it would have been more productive.
In any case, the microbes that I did encounter were quite large and interesting; Euglenoids, Phacus, etc. This Euplotes was large enough to be pinned down by the cover glass, which allowed me to get a nicely detailed image.