Author: Reina Kornmayer

Microplastics, tiny fragments of plastic less than 5 millimeters (about 0.2 in) in size, have become a growing topic of conversation in recent years. Since 1950, about 8 million tons of plastic have been produced, but only about 10% of that has been reused and recycled. The rest of that plastic has found its way to landfills, the ocean, and roadsides, to name a few. Primary microplastics are plastic materials designed to be small in order to perform a specific function. Think about the exfoliating beads you see in face cleansers, or the grittiness you can sometimes feel in your toothpaste. Secondary microplastics come from the breakdown of larger plastic materials: water bottles and storage tubs are good examples. Through wear and tear, the effects of the sun, wind, and water, larger plastic items break down into tiny pieces. Most plastics that have been produced take thousands of years to fully decompose; so in the meantime, those tiny plastic pieces end up in the air we breathe, the water we drink, the food we eat, and the soil beneath our feet.

Most microplastic studies have focused on the ocean. How do microplastics affect marine life, and in turn, how would that consequence affect us? Research has shown that microplastics are often absorbed and ingested by sea creatures, and if they survive having the plastic inside of them, and do not become ill or die from the toxins that might have come along with the plastic pieces, then those toxins and fragments stay within the animal. When that animal is eaten, the plastic moves up a notch in the food chain; the amounts of microplastic present within a creature’s tissues increase the further up the food chain you go. Microplastics have been found in people, and studies have found microplastics in our food, honey, and sugar. They are everywhere, and a recent study published in the Science of the Total Environment journal in January of this year revealed that microplastics had been found in soil samples collected more than seven meters (23 feet) below the surface. The samples had originally been collected as part of an archaeological excavation in the 1980s, and, until now, the samples were thought to be from stratigraphic layers untouched by human activity.

The authors of the study caution that their research is in the early stages, but for archaeologists, this development might result in seismic changes to the field. Preserving prehistoric and historic resources in situ, that is, in their original state, as opposed to digging them up or moving them elsewhere saves time and resources. The idea is that being encased deep within the earth will preserve the resource for a long time, but this research presents the distressing notion that microplastics have been contaminating archaeological sites for decades. Why are microplastics a problem in soils? Not only are they ingested by soil-dwelling animals and absorbed by vegetation, but the presence of microplastics can alter the chemical and physical composition of the soils and sediments themselves. As a result, sites, features, artifacts, and remains buried underground may deteriorate more rapidly, and the chemicals released from the microplastics as they decay could potentially compromise radiocarbon dating and trace element analyses.

The researchers emphasize that soil is often not studied holistically as a complex ecosystem. Archaeology as a field tends to view soils and sediments solely as the casings surrounding the good stuff, and not as an entity that acts on and is acted upon by the artifacts and ecofacts humans leave behind. In order to fully understand how the presence of microplastics will affect preservation, more research must be performed on soil as an ecosystem, taking into account its physical, chemical, and biological components together. Soils are unique in that they can change from one kind to another, if the environmental factors change. Studies on microplastics in our oceans, our air, and our food are important, and should continue. The consequences of microplastics in our soils, while still relatively unknown, are consequences all the same. More attention should be focused on figuring out exactly what effect those consequences will have.

Photo courtesy of Only in Your State

Today, the Great Dismal Swamp, located across southeastern Virginia and northeastern North Carolina, is a national wildlife refuge encompassing about 112,000 acres. Having once covered over a million acres of the coastal plain, this sprawling system of wetlands is home to black bears, red-cockaded woodpeckers, southern plains bumblebees, Dismal Swamp short-tailed shrews, cricket frogs, pawpaw trees, and many other species of wildlife. A biodiversity hotspot with botanical species from both northern and southern climates, biologists with the U.S. Department of Fish and Wildlife and the National Wildlife Refuge system are hard at work making sure it remains a viable habitat. This involves working with the U.S Army Corps of Engineers to manage the swamp’s hydrology. The natural flow of ground and surface waters within the wetlands was heavily disrupted by the construction of drainage ditches, one of which was commissioned by George Washington, who recognized the economic potential of harvesting timber from within the swamp. That little nugget of knowledge provides us with our first clue that there is more than a rich natural history in the Great Dismal Swamp: there is a rich cultural history as well.

Photo courtesy of Allison Shelley and Smithsonian Magazine

Almost impossible to navigate by canoe or by horseback, the dense quagmire was home to indigenous groups as far back as 6,000 years ago. When European colonists arrived, the surrounding region was turned into farmland and worked by enslaved Africans, enslaved indigenous people, and indentured servants. Those wanting to escape slavery would often head for the swamp, where they were willing to risk running into venomous snakes, mosquito hordes, and the boot-sucking peat muck to secure their freedom. Thus, the Great Dismal Swamp became a stop along the Underground Railroad, where runaway slaves could hide and receive aid from allies on their way to northern states and Canada. The swamp became notorious as a hideout for runaways, and the North Carolina State Assembly even passed the Act to Provide for the Apprehension of Runaway Slaves in the Great Dismal Swamp and for other purposes in 1847. Not everyone who escaped into the swamp chose to leave it behind, though; many formerly enslaved people chose to permanently remain deep within the belly of the swamp. Living on islands, they learned subsistence farming techniques from the dwindling indigenous population. Hunting, fishing, and foraging supplemented the crops they grew, and, according to archaeologist Dan Sayers, they would re-use ancient stone tools that they found in the muck. These communities became known as maroons, and they were often completely isolated from the outside world. References to maroons within the swamp can be found in historical resources dating back to the early 1700s.

Pawpaw tree and fruit, courtesy of Butterfly Gardens to Go

Sayers has become the world’s foremost expert on maroon communities in the Great Dismal Swamp, and one of the ways he and his team located potential cultural sites was by examining maps of the vegetation. Tree species that need higher, drier ground to thrive revealed the locations of “at least 200 habitable islands” within the wetlands, which may have been home to hundreds of maroons. The interpretation of different vegetative communities within the wildlife refuge’s borders provided Sayers with a way to identify habitable tracts of land. This illustrates the point that our natural and cultural resources are intricately linked, and to only focus on the preservation and interpretation of one without the other does us a disservice. More and more, an interdisciplinary approach is required to gain a fuller picture of our past. Written records of maroon life are scarce, which explains why the fields of history and archaeology traditionally overlooked this portion of history. Sayers, though, recognized how archaeology could reveal the swamp’s secrets, and that botanical surveys could point him to the places most likely to have secrets to reveal. Members of the maroon communities would have, undoubtedly, recognized the plant life that signaled higher, drier ground: pawpaw trees require well-drained soil, so they would have only been able to grow on the islands. Producing a large, tropical-like fruit, pawpaws would have been an important seasonal source of food for maroons. So, the next time you visit the Great Dismal Swamp, or any of the other beautiful natural parks and wildlife refuge systems in the country, try to think about how humans of the past interacted with the environment, and how nature impacted them in return. Our parks and wildlife refuge systems still have a lot to reveal about our nation’s cultural heritage.

Photo courtesy of Allison Shelley and Smithsonian Magazine

In mid-October of this year, the U. S. Fish and Wildlife Service announced that they will be delisting 21 species from the Endangered Species Act. This follows the Fish and Wildlife Service’s September 2021 proposal of 23 species that they were seeking to delist. Were these species removed because their populations rebounded? Nope. They went extinct, though two of the originally proposed 23 species, a Hawaiian perennial herb and the ivory-billed woodpecker, are in a limbo state while the service analyzes more data. What stood out about this list was the taxonomy of the species: most are birds and mussels. The Hawaiian Islands were hit especially hard, as eight out of the ten bird species were only found there. Habitat destruction, diseases, and invasive predators decimated the populations by the mid-1900s. By the time they were placed on the Endangered Species List, it was already too late. According to the American Bird Conservancy, all but one of the species was already extinct by then, and efforts to capture and breed the remaining members of the Po’ouli species failed. The same is true for the eight freshwater mussel species, with ranges throughout the southeastern United States. They were listed as endangered around the same time they were last seen in the wild. Martha Williams, the Director of U.S. Fish and Wildlife, stated that she hoped this would help the public recognize the importance of starting conservation efforts earlier. The Endangered Species Act turned 50 years old this year, and during that time it has been credited with saving 99% of the listed species from extinction. 

You may ask, what is the big deal about a bunch of birds and mussels? Birds, and many of the species native to Hawaii, often act as pollinators. Many also spread the seeds and control pest species of insect. Some plant species are now struggling, because their main pollinators and seed dispersal agents are no longer present. If those plants are unable to adapt to this change in their environment, they too may eventually go extinct. On Hawaii the loss of those species is even more devastating because of their cultural significance to the indigenous people. As for why you should care about a bunch of freshwater mussels, our question for you is: do you want clean water or dirty water? Mussels filter the water in the rivers and streams in which they live. A tank full of water with mud and algae will be noticeably cleaner a few hours after mussels are placed inside. Today, though, in many rivers and streams, it is not just algae or mud that the mussels are filtering out: it is also chemicals from fertilizers, production plants, and medications that people have flushed down their toilets. These chemicals are not only dangerous for us but are also dangerous for the mussels. These creatures are incredibly sensitive to contaminants, so it does not take much to throw a population out of whack. On top of the increasing levels of pollution in our waterways, most species of mussel need species of fish in order to reproduce. An adult mussel will lure a fish towards it, and when it is close enough the mussel releases hundreds or even thousands of mussel larvae. The fish carry them around until they are big enough to survive on their own. The problem is that mussel species often only have a handful or even a single fish species with which they engage in this parasitic relationship. Due to water pollution, overharvesting, warming waters, and the damming of waterways, fish populations are also on the decline. 

What should be taken away from this delisting is that the species that are protected are not being protected for frivolous reasons, but oftentimes have an impact on resources that impact humans. Conservation actions should be taken earlier to give individual species a better chance. As their populations grow, our natural resources improve and grow as well, and can be sustainably utilized for generations to come.