Corbicula fluminea is a species of freshwater clam that is native to eastern Asia and has become an extraordinarily successful invader of freshwater ecosystems and is found on every continent except for Antarctica (Leff et al., 1990; Hornbach, 1992; Karatayev et al., 2007; Lucy & Graczyk, 2008; Sousa et al., 2008a; Crespo et al., 2015). It is widely theorized they were introduced as a food source on the west coast of the United States and were first discovered in the country in 1938 (Sinclair & Isom, 1963; Counts, 1981). Impressivly, C. fluminea have the highest secondary production values ever measured for a species colonizing a freshwater ecosystem and the highest record net productivity for any bivalve (McMahon, 2002; Sousa et al., 2008b). While there are multiple species of Corbicula that are invading aquatic systems, the most common species is C. fluminea (Renard et al., 2000; Siripattrawan et al., 2000). There are several factors that have led to successful invasions of C. fluminea including high fecundity, functional hermaphroditism, self-fertilization, rapid sexual maturity, lack of a parasitic life stage, pedal feeding (that is feeding via the cilia on the foot) and filter feeding, and the ability to disperse across long distances (McMahon, 2002).Continue reading
When beachcombing in the Bahamas I discovered a number of mostly round, about quarter size, water filled, and plastic-like outside objects. I brought one of the odd objects to my professor and he informed me that they were a kind of algae (Ventricaria ventricosa) known commonly as sea pearls (also called bubble algae and sailor’s eyeballs). After recovering from the guilt of poping a whole bunch of sea pearls, thinking they were some kind of trash, I researched more about them. And in case you were wondering, they poped kind of like a water balloon. They were filled with water and not much else. Their cell wall was very plastic like and rubbery. Sadly, they did not resemble a large version of the classic plant cell you learn about in biology class.
The order Lepidoptera contains butterflies and moths. There are over 180,000 species in the order which is divided into 126 families and 46 superfamilies. They account for 10 percent of known species worldwide. The order is defined by the scales that cover them, wings, and a proboscis. They also undergo a complete metamorphosis between the larvae and adult stage. Some scientists have even theorized that caterpillars and adults are different species and metamorphosis changes the genes that are active. This is known as the death and resurrection theory. Butterflies and moths are important pollinators and members of the food chain. Because there are so many families in this group I have chosen to just focus on 5 families for now.
- this is a moth family with over 2,300 described species in it
- adults have large bodies and wings
- the bodies have hair like scales on them
- wings often contain eyespots
- front and back wings overlap
- wingspans are typically 1-6 inches but the atlas moth (Attacus atlas) has a wingspan of 12 inches!
- notable members include the giant silk moths, emperor moths, and royal moths
- this family contains some agricultural pests as well as the moths that spin silk
- Papilionidae, or the swallowtail butterflies
- this family has over 550 species
- while most species are tropical these butterflies can be found on every continent but Antartica
- the family included the largest butterflies in the world with the largest being Queen Alexandra’s birdwing (Ornithoptera alexandrae) which can have a wingspan of 9.8 inches
- the larvae in this family have a defend organ called an osmeterium
Stone Mountain is one of metro Atlanta’s most popular hiking spots. It also happens to be one of the 7 natural wonders of Georgia joining the ranks of; Amicalola Falls, Warm Springs, Okefenokee Swamp, Providence Canyon, Radium Springs and Tallulah Gorge. Stone Mountain was formed from an upwelling of magma, about the same time that the Blue Ridge Mountains were formed. Stone Mountain is a giant igneous monolith (meaning it is one continuous rock) that has a circumference of 5 miles at the base above ground but extends further underground. While it is very large it is not the largest piece of granite in the world, and some of the mountain is not composed entirely of granite as composition ranges from quartz monzonite to granite and granodiorite (according to the Georgia Geological Survey Bullet). It is unclear what the largest piece of granite in the world is; I’ve heard the same claim from the Polar Caves in New Hampshire and from a rock in Yellowstone.
There are many interesting species to observe at Stone Mountain as well. During the rainy season in the pools clam shrimp (Laevicaudata) and fairy shrimp (Anostraca) can be observed. Both of these are orders of small bivalves and crustaceans. The fairy shrimp is most commonly known as the sea monkey or brine shrimp. Clam shrimps are very similar but they have a protective shell around the shrimp. They are both able to enter a state called diapause, in this state the eggs basically dry out and remain that way until it rains again. The eggs can even survive being out in space! Centuries later the eggs are still able to hatch. The species are not mobile unless they are aided by wind, bird’s feet, or currents. Fairy shrimp can well found on every single continent, including Antarctica.
Does the title of this post sound like Greek to you? Simply put, benthic macroinvertebrates are little tiny bugs that live in our waterways, but you are able to see them with your naked eye. They are often the larvae of insects that we are more familiar with like blackflies, mayflies, and more! While ponds and lakes do have some, there is a higher number of species found in running waterways. And they can actually tell you a lot about the water that they live in! Many agencies use them as a measure of water quality. In a nutshell, some species are more tolerant of pollution than others. So you collect insects for a certain amount of time, count how many are pollution tolerant, pollution sensitive and pollution intolerant, and then do some easy math! You can also calculate what is called an EPT index. This is based on how many mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera). This is great if you have a stream running on your property and want to know more about its health.
Because there are so many species, typically macroinvertebrates are broken down into families or orders. A dichotomous key is very helpful in their identification. In West Virgina alone, there are 538 species that the state has identified! This level of identification is hard without breaking out a microscope. In high school, I volunteered with a stream team that was partnered with a local university. We would go out and collect the samples and analyze them. While the EPA does have an SOP for sampling macroinvertebrates most state agencies have their own SOP which can be found by simply googling XYZ State macroinvertebrate sampling. I’m basing the rest of this information on the Georgia EPD SOP. These SOPs are similar to the EPA’s SOP but are adapted to be more effective based on the eco-region. I will detail how to conduct surveys in a future post but for now, let’s look at the different groups of macroinvertebrates.