Benthic organisms are remarkably diverse and vary with habitat. They include protozoa (like amoebas), sponges, cnidarians, flatworms, nematodes, isopods, crayfish, amphipods, mollusks, gastropods, leaches and aquatic worms, pelecypods, insects, and fish. Benthic species I have observed in my area (Cobb County, Georgia) include the Asian Clam (Corbicula fluminea), larval brook salamanders (Eurycea sp.), common sunfishes (Lepomis sp.), the Chattahoochee Crayfish (Cambarus howardi), caddisfly larva (Order Trichoptera), damselflies and dragonflies larval (Order Megaloptera), mayfly larva (Order Ephemeroptera), dragonflies and damselfly larval (Order Odonata), aquatic worms (phylum Annelida), Eastern Dobsonfly larval (Corydalus cornutus), water snakes (Nerodia sp.), longjaw minnow (Ericymba amplamala), river Cooter (Pseudemys concinna), true bugs (Order Hemiptera), true flies larval (Order Diptera), beetles (Order Coleoptera) and stonefly larval (Order Plecoptera). It is worth noting some of these species may only occupy the benthos for a period.
Image of a Brook Salamander. Brook salamanders are a genus, Eurycea, image by Lauren Schramm
In some streams, Asian clams, an invasive aquatic species, can be one of the largest components of the benthic invertebrate community (Poff et al.,1993), however this is not the case in all streams in Cobb County. Black et al. (2003) evaluated benthic macroinvertebrate populations of two local streams: Sope Creek and Rottenwood Creek. In Sope Creek they found Ephemeroptera and Diptera to be the dominant orders. In Rottenwood Creek they found Trichoptera and Diptera to be the dominant orders.
An Asian Clam (Corbicula fluminea). Image by Lauren Schramm.
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).
Georgia currently has 30 native frog species and two introduced frog species that fall into six different families.
The most distinct of these families is Bufonidae or the true toads. All toads will be found in this family. All toads are frogs but not all frogs are toads. Toads are a specialized group of frogs who typically have warty dry skin, are short and stubby, and large glands on the sides of their heads that kind of look like shoulder pads and are called parotoid glands. Toads can actually aim these glands at predators. The glands release a toxin, called bufo. That’s why it’s common to see toads hopping around during the day. The eggs are typically laid in long strands. Toads also have no teeth. Worldwide there are 604 species in this family. In Georgia we have 4 species; American Toad (Anaxyrus americanus), Fowler’s Toad (Anasyrus fowleri), the Oak Toad (Anaxyrus quercicus), and the Southern Toad (Anaxyrus terrestris). In the Metro Atlanta area, it’s common to hear both American and Fowler’s toads calling. The Ameican toad sounds like a long musically thrill that lasts between 6 and 30 seconds. The Fowler’s Toad sounds like a harsh thrill, kind of like a nasally WAAAHHHH.
The largest family of frogs in Georgia is Hylidae or the tree frogs, chorus frogs, and cricket frogs. Worldwide the family has 710 species. They all shared a claw-shaped finger which is found at the end of their toe pad. The toe pads function not like suction cups, but via wet adhesion, similar to 2 pieces of wet glass sticking together. In Georgia we have the Northern Cricket Frog (Acris crepitans), Southern Cricket Frog (Acris gryllus), Bird-voiced Treefrog (Hyla avivoca), Cope’s Gray Treefrog (Hyla chrysoscelis), Green Treefrog (Hyla cinerea), Pine Woods Treefrog (Hyla femoralis), Barking Treefrog (Hyla gratiosa), Squirrel Treefrog (Hyla squirella), Cuban Treefrog (Osteopilis septentrionalis), Mountian Chorus Frog (Pseudacris brachyphona), BRimley’s Chorus Frog (Pseudacris brimleyi), Spring Pepper (Pseudacris cruicifer), Upland Chorus Frog (Pseudacris feriarum), Southern Chorus Frog (Pseudacris nigrita), Little Grass Frog (Pseudacris ocularis), and finally the Ornate Chorus Frog (Pseudacris ornata). The Cuban Treefrog is actually an invasive species that is twice as large as our native treefrogs and it consumes them! It’s really hard to find because it’s a treefrog and so there is not much we can do about it’s invasion. The upland chorus frog (sounds like running your finger along a comb), spring pepper (sounds like bird-like peeps), Cope’s gray treefrog (harsh, high pitched trill), green treefrog (nasally and duck-like), bird-voiced treefrog (like a bird call whit-whit-whit), squirrel treefrog (harsh repetitive, squirrel-like call), and northern cricket frog (sounds like two marbles being tapped together) can all be found in the Metro Atlanta area.
The family Ranidae contains true frogs who have smooth and wet skin. Worldwide they have a large range. Generally, they are aquatic or live close to water. This family is probably what comes to mind when most people think of frogs. In Georgia you can find Gopher Frogs (Lithobates capito), Bullfrogs (Lithobates catesbeinanus), Green Frogs (Lithobates clamitans), Pig Frogs (Lithobates grylio), River Frogs (Lithobates heckscheri), Pickeral Frogs (Lithobates palustris), SOuthern Leopard Frogs (Lithobatessphenocephalus), Wood Frogs (Lithobates sylvaticus), and Carpenter Frogs (Lithobates virgatipes). Bullfrogs, green frogs, pickerel frogs, and Southern leopard frogs all have calls that can be heard in the metro Atlanta area. Respectively the calls sound like a repeated jug-o-ruummmm, like a banjo pluckling, a snoring person, and the sound of squeezing a balloon.
The following was a term paper written for my conservation biology class in collaboration with Hallie Draegert
It is a well-known fact that the human population is increasing in size. The growth of one population, the humans, tends to impact other populations negativity. In this case, the concern is the impact it has on wildlife populations. As long as wildlife and human populations coexist problems will arise. These problems can occur in response to tension between local human communities and the attempts of organizations working to conserve native populations of animals. Often these organizations seem to forget that the local’s livelihoods depend on exploiting the local animals. This has led to the creation of conservation models that do not work because they did not consider the local politics.
One of the most common crimes committed is poaching. Poaching has led directly to the extinction of many species and induces stress, on currently stable species. This could make future extinction of the population an issue that needs to be addressed. Since poaching is a serious problem for highly stressed species, it is critical to work to prevent the crime. There are many current techniques used to reduce and combat poaching. However, the issue has not been fully resolved. This is likely because only a single model is in use at a time in an area.
There are many dynamic relationships in the rainforests of the world. Which is expected as they are home to up to 40 percent of known plant and animal species. Within the forest there are a widely variety of symbiotic relationships, which means there are interactions between two species. For some species the relationship is beneficial for both parties, this is call mutualism. For example the Brazil nut trees (Bertholletia excelsa) produces a nut that is an only be cracked by a few species, one of which is various agouti (Dasyprocta sp.) which is a small rat like animal. The tree benefits as it’s seeds are dispersed and the agouti receives a free meal.
English: A Central American Agouti (Dasyprocta punctata) in Panama experimenting with a western diet.
In some cases one species is unaffected and the other benefits, this is commensalism. A example of this would be a frog sheltering itself from a storm event under the leaves of a plant. The plant is un effected but the frog benefits. Lastly, parasitism is when one species is harmed and the other benefits. Bot flies are a common tropical parasite that lay their eggs on a mammal host. The eggs then hatch and the larva develop in the skin of the host animal.
A frog in the rain in Belize. Image by Lauren Schramm
Competition is a symbiotic relationship in while two species use the same resources. Because it requires an energy investment both species are harmed, but the harm may be unequal. Many rainforest plants are animal pollinated or their seeds are dispersed by animals. Resource partitioning occurs when a resource is divided among species in some way like time or place. One way plants reduce their competition against each other is by targeting different animal groups. For example flowers pollinated by bats are often white making them easier to see at night, while flower pollinated by other animals are red, orange, and yellow. Bat pollinated flowers also contain a musky smells, while flower pollinated by moths, bees, and other insects have a strong fragrance. Plants also reduce competition by flowering and fruiting at different times. This is one reason there are always flowers and fruits available in the rainforest at any given time.
A harmful aquatic algae bloom is when there is sudden a rapid growth of algae. In the past these were more commonly referred to as red tides. These populations of algae in term then produce extracellular compounds that can cause harm and even death to humans and wildlife and fish. Shellfish that are subjected to HABs cause humans to get sick. In rare cases people can even die. HABs most commonly occur in the oceans and large freshwater lakes, such as the Great Lakes.
Often HABs occurs due to nutrient runoff but it is important to understand these have been occurring for millions of years. There are fossilized HABs and fossils of whales found in a proximity and quality near the fossilized HABs that is is theorized the HABs resulted in the death of the whales. Climate change is increasing the frequency and intensity of HABs so it is clear we need to develop tools to predict and mitigate risks with HABs.
I looked at research into using remote sensing to predict algal blooms of Karenia brevis in coastal Florida. This algal is responsible for the most red-tides in Florida. It produces a neurotoxin that kills aquatic life and makes shellfish toxic to humans. Researchers used a geographic information system (GIS) to develop a machine learning method to detect harmful algal blooms (HABs).
The Great Lakes contain 20 percent of the world’s freshwater (McBean 2008) and are already facing the impacts of anthropogenic climate change. The Greats Lakes have seen a 10 to 25 percent increase in precipitation from 1981 to 2010 (NOAA, 2019) due to increased evaporation. The amount of precipitation is predicted to increase by 12.5 percent by 2080 (Wang 2016). Increased rainfall has led to increased nutrients washed out of soils, as found in two studied watersheds (Wang 2018). In one watershed the amount of phosphorus washed out, due to soil erosion, could increase by 108 percent by 2099 (Ibid). These additional nutrients can result in nutrient loading and therefore algae booms and eutrophication in the Great Lakes.
One reason for the increased precipitation is the reduction in ice cover, which results in more evaporation. Ice cover has decreased by 71 percent on the Great Lakes from 1973 to 2010 (Collingsworth, 2017). Many commercially important fish species allow their eggs to overwinter below the ice, with reduced ice cover their eggs are more susceptible to wave action damage (Ibid). Models to predict how much ice coverage will be reduced vary widely but they all agree that the coverage will reduce by 2050. One initial benefit of reduced ice cover is that it will reduce the number of winter kills as there will be more circulation of oxygen.
Georgia experiences several droughts including one from 2005 to 2007 that made headlines as lake levels in Lake Lanier, which serves as a major water reservoir for Atlanta reached record lows. It was shown that this drought cost $2 billion dollars in loses, which included $87.6 million in recreation spending lost from visitors to lake Lanier as the lake levels were down 20.21 feet from full capacity. It was shown that this drought was caused by an increase in consumption rather than anthropogenic climate change. There have been other major droughts in 1954-1956, 1981, 1985- 1988, and 1998 – 2002, 2012 to 2013 and 2017. To lessen the effects of droughts in the future of Georgia, education, voting with our dollars as consumers, and a change in diet are key.
The county that I live in, Cobb County, has an excellent water stewardship program. They have a team of scientist that travel the county and regularly test the quality of streams and rivers. They also provide lots of programming with the public. They are home to the largest adopt-a-stream program in the country which is a great way to engage citizens in water quality issues. They often host workshops where you will make and take home a rain barrel. They also send out quarterly newsletters on water issues in the county and host stream clean ups in partnership with the Department of Natural Resources Rivers Alive program.
The Gaia theory was first introduced in 1979 by James Lovelock in his book Gaia a New Look at Life on Earth. The basic idea is that the earth is a self-regulating entity. While the theory was a scientific one, it launched a new pantheism religion known as Gaia worship or Gaianism, whose practitioners are known as Gaians. While Gaia worship is not new and Gaia is the oldest divine being who dates back to prehistoric times, the concepts of this religion are. For example, Gaianism is monotheistic while Gaia worshipers of the past were polytheists. Central to both the Gaia theory and the beliefs of Gaian is the concept that the earth is a self-aware being that is able to self-regulate. The relationship between the earth and Gaia is that of your body and you. The Gaians believe that this is their goddess. Many of the core concepts of this fringe pagan group stem from the Gaia theory or are directly linked to it. The three core concepts of Gaianism are honor the earth, reduce human impact on the earth, and be respectful of life in all forms and of the systems that support them.
The religion tends to be much unorganized due to the nature of pagan religions. There is a very negative cultural associated with the word pagan, therefore, many pagans prefer not to state their religion. In addition, those who have not heard of the religion obviously will not follow it. Since it is not that popular not many people have heard of Gaianism. However, the most organized group of Gaianism developed from a Wicca coven in New York City. This group called themselves Gaia Group, but was created from Coven of Caerlleuad (Castle of the Moon) in August of 1983. This group saw that other Wicca groups were changing to have more future thinking outlook rather than trying to preserve the traditions of the past. The group saw this as holding them back due to the fact the negative views of Wicca are based mostly on their past practices. The group also saw the belief systems of the past as no longer relevant. In order to make the religion more universally accepted they replaced welsh traditions and gods with an ethic focused on Gaia. The group focuses on the ideals of repairing this world and the fact that we are members of a larger community. They took part in many protests and had a strong emphasis on community service. Unfortunately, the group disbanded in 1998.
If you spend any amount of time in the town of Wimberly, Texas locals will be sure to mention the flood that happened in 2015. 13 people died and 350 homes were destroyed. However, there was a silver lining to the flood, a large number of fossils, including dinosaur footprints were discovered in the Blanco River. These footprints were discovered when the City of Blanco GIS manager was reviewing aerial photographs. From the photographs, we can clearly see the footprints of a four-legged dinosaur (or sauropod). Based on the distance between the front feet, foot size, time at which the tracks where made, and stride length it’s like that the tracks belong to Paluxysaurus Jonesi, or as anyone who has watched the land before time would call it, a longneck. It’s actually the state dinosaur of Texas. The footprints are located on federal owned land that you can only access with a ranger and I’m not sure if the public can visit. I was able to visit through the master naturalist program. Here is a link to other dinosaur footprint site in Texas you can visit though.
There were a ton of other fossils the rangers pointed out to us as well. The most mind-blowing to me was a microfossil. At one point we were walking in some small gravel and the ranger told us to look down. Turns out we were actually walking on millions of microfossils of a former unicellular organism that lived in the ocean. The sheer number of them was astounding. The concept of microfossils is pretty crazy too. Researchers can actually find microfossils of plankton or pollen and learn a lot about what past environments where like.
As a cave lover, I have been on a lot of cave tours and during the tour, the cave ecosystem is always something that is discussed. They are very unique and fragile systems. The most important factor in depending on what the environment is like in the cave is what zone you are in. Caves are divided into 3 zones; the entrance, the twilight zone, and the dark zone. In the entrance, there might be green vegetation and there is a lot of light, the temperature is more variable. In the twilight zone, there is less light and minimal plant life. Finally, in the dark zone, there is no plant life and the temperature generally stays the small all year round. In most caves, it’s around 55 degrees Fahrenheit or so. All of the nutrients in this zone have to come from outside the cave.
Trogloxenes and Troglobites are also important terms to know for understanding cave ecosystems. A trogloxene is a species who uses caves but they don’t spend their entire life in one. An example of this is bears or raccoons. Bats also fall into this category as they must leave caves to find insects to consume. The material brought in by trogloxenes and their poop are the only resources that troglobites have to use besides debris that may wash into a cave during a storm. In a lot of caves, bat dropping can actually serve as the major source of nutrients. Troglobites spend their entire lives in caves. A lot of caves have unique species of troglobites because they don’t leave and therefore don’t have any other populations to breed with. These species generally have really interesting cave adaptions like lack of eyes or any pigment. Pigment is lost in the cave environment frequently because it doesn’t benefit the organism and is energetically expensive to produce. Common examples of these species are cave crickets, spiders, psuedoscorpions, salamanders, crawfish and more.