Check out the BHSU Biology Program

Discover our Research in Biology


Here at Black Hills State University we are actively engaged in research throughout the year. If you are interested in doing research contact one of the faculty members with the same interest to propose your plan.

Posted Research Projects:

Other Student Research:

  • Brandi Wood traveled in Hawaii with Dr. Steve Anderson to assess the distribution of pahoehoe lava flow surface morphology at Kilauea volcano, and used the results as the basis for comparison to similar flows on the Martian surface. Brandi coauthored a paper presented at the Lunar and Planetary Science conference and two others that were published in Earth and Planetary Science Letters. Brandi Wood was funded by a Nelson Scholarship. 

Faculty Research

    Black Hills State University's Faculty is very active in research throughout the year. With their broad range of research interests, the faculty can assist and guide students in the development their own research. If a student is interested in doing research, they should contact one of the faculty members with the same interest to propose their plan.
     
  • David Bergmann: Bacterial oxidation of ammonia and methane, microbial ecology.
  • Holly Downing: Behavior, nest construction, and glandular development in social insects.
  • Audrey Gabel: Survey of Black Hills fungi; mycology
  • Mark L. Gabel: Flora of the Black Hills, systematics of Poaceae, Miocene flora of the Great Plains
  • Charles F. Lamb: Comparative vertebrate neuroanatomy and the ecology of aquatic insects.
  • Shane K. Sarver: Evolutionary genetics
  • David Siemens: Plant-insect interactions, plant ecology, ecological genetics, secondary plant metabolism
  • Brian E. Smith: Conservation biology and herpetology.
  • Tamara Lawson: Growth and development of insects.

Intro

Sensitive Herpetofauna of the Black Hills National Forest
by Nate Stephens and Brian Smith

The Black Hills is home to 23 species of reptiles and amphibians, several of which are rare. The United States Forest Service considers four species of particular concern and classifies them as sensitive species on the Black Hills National Forest. Black Hills State University, in cooperation with the Black Hills National Forest, has been working for the past several years with the U. S. Forest Service to design management strategies to conserve these species. In this presentation we describe these species and threats to their populations.

Tiger Salamander

The tiger salamander has one of the largest ranges of any amphibian in the world. In parts of its range it is threatened with extinction, but in many areas its population status is simply unknown. Its aquatic larval stage has been fairly well studied, but despite the large numbers of studies we still know little about the basic biology of this salamander and especially about the terrestrial stage of its existence.

The tiger salamander is even less well known in the Black Hills. We have found adults throughout the Black hills but at unpredictable times in unpredictable locations. Breeding ponds are very poorly known. Because terrestrial adults spend most of their time underground we have almost no knowledge of their habits. Sexually mature larval forms are also found in the Black Hills in various permanent springs and ponds. However, we know little about where they are found as well.

Like all amphibians the tiger salamander can be affected by diseases, pollution, acidification, over development, and over collection. However, our most important recommendation as regards the tiger salamander is simple survey work. We need to survey ponds throughout the Black Hills searching for this species at appropriate times of the year to determine the abundance and distribution of the tiger salamander in the Black Hills.

Northern Leopard Frog

The northern leopard frog is threatened with extinction or is extinct across large parts of its wide historical range. Once one of the most widely distributed frogs in North America, its range has been shrinking for decades. A variety of reasons have been given for the extirpation of the northern leopard frog across its range, including over development, diseases, over collection, pollution, loss of the ozone layer, acidification, and other causes. Recently, deformed northern leopard frogs have been found across various parts of the upper Midwest of the United States. These deformations are currently unexplained.

We believe that northern leopard frog populations may still be secure in the Black Hills, but are worried that these populations could also disappear. We also know very little about the population status and abundance of this species in the Black Hills. We have recommended immediate surveys to determine population sizes in the Black Hills. We have also recommended that steps be taken to secure the small wetlands in which this species breeds and to protect riparian corridors along which northern leopard frogs move when traveling from pond to pond.

Redbelly Snake

The redbelly snake, Storeria occipitomaculata, is a species of eastern North America. It is a small snake that feeds on soft-bodied invertebrates, such as slugs, that it finds in moist areas under cover items such as rocks, logs, and decaying plant litter. The life history of redbelly snakes is geographically variable, so studies in other regions may not help us to understand the life history of populations in the Black Hills, where they have not been studied. The species is divided into three subspecies, two of which are found exclusively in the eastern United States. The third is found in the west and was thought by taxonomists to be confined to the Black Hills. A recent specimen found near Bison, however, shows that redbelly snakes may be more widely distributed in South Dakota than previously thought.

The Black Hills redbelly snake, Storeria occipitomaculata pahasapae, was described in 1963 from the Black Hills. However other studies have found them in Minnesota, North Dakota, Nebraska, and Manitoba. Within the Black Hills, the snake is thought to inhabit most habitats that are threatened by encroaching ponderosa pine forest. The snakes may be threatened by loss of habitat, as wetlands are disappearing in the Black Hills. This may affect their prey, possibly slugs, which are very susceptible to desiccation. Management for the Black Hills redbelly snake would mean the preservation of these habitats and returning the historical diversity of habitats that occurred throughout the Black Hills.

Pale Milk Snake

The milk snake, Lampropeltis triangulum, is a diverse species with possibly the widest range of any American snake. This species is divided into 25 subspecies that vary in color, pattern, and general biology. Throughout parts of their range they are effective mimics of the dangerous coral snake. Because of their bright colors and harmless nature they are often kept as pets. The northernmost and probably least know subspecies is the pale milk snake, Lampropeltis triangulum multisriata.

The pale milk snake is found throughout the Black Hills in Wyoming and South Dakota. This rare predator is thought to feed mainly on reptiles and small mammals. Although it is not dangerous to humans, it is often mistaken as the venomous coral snake and killed on sight. Coral snakes are not found within the range of the pale milk snake and there is no danger from them in South Dakota. The pale milk snake spends most of its time hiding and is therefore difficult to find, let alone study. Finding a pale milk snake in the Black Hills is rare and care should be taken not to disturb its habitat, as we know very little about them in the area. The management of this snake is concerned with habitat diversity, which has been shown to increase the abundance of prey items the snake may use.
 

Conclusions

There are several constant themes running though each of these accounts. Probably most importantly the Black Hills area has long been neglected by herpetologists. It is one of the last parts of the United States to still lack basic survey work on reptiles and amphibians. We suspect that several management actions, including cattle grazing, logging, development, and mining, can have adverse affects on these species. However, before designing wise management strategies that accommodate the interests of the wide variety of users of the Black Hills National Forest, we have recommended a program of extensive surveys to determine the status and abundance of these species.

Biology Research in Microbial Inhibition

Abstract

Microbial Inhibition in Response to Treatments of Hydrogen Peroxide and Formalin on Landlocked Fall Chinook Salmon Eyed Eggs as Determined by Scanning Electron Microscopy
by Hans Stephenson, Mike Barnes, and Mark Gabel

Scanning electron microscopy was used to compare microbial growth in landlocked fall Chinook salmon eggs receiving daily 15 min treatments of 1,667mg/L. formalin, 700 mg/L. hydrogen peroxide treatments, or no chemical treatments during incubation in vertical-flow incubators from egg eye-up to hatch. In eggs that were not chemically treated, bacterial numbers significantly increased from 2,413 bacteria/mm2 on the external egg membrane surface at the start of the experiment to 69,598 bacteria/mm2 12 days later. Eggs receiving no chemical treatment had bacterial numbers at the end of the experiment that were significantly greater than those on eggs receiving either of the chemical treatments. The number of bacteria attached to the external egg membranes did not significantly differ between eggs treated with either formalin or hydrogen peroxide throughout the study. Fungal growth was negligible and only observed in control eggs. The external membranes of control eggs were visibly degraded over the 12-day period. Egg survival was significantly lower in control eggs compared to eggs receiving either the chemical treatments, and was significantly correlated to bacterial numbers.

Materials & Methods

Incubator trays were loaded with approximately 1522 eggs per tray. Water (11 degrees C) flowing over the trays at 8 L per minute was untreated (control), treated with 1667 mg/L of formalin, or treated with 700 mg/L of hydrogen peroxide (H202). All trays were “hand-picked” to eliminate fungal mortality in the control trays. Treatments were continued for twenty days.

The eggs were taken from the hatchery on selected days and transported in a buffer solution. The specimens then underwent inspection using the scanning electron microscope. During low vacuum observations, no additional preparation was necessary. However, for high vacuum observations eggs were dissected in buffer, treated with gluteraldhyde, osmium tetroxide, dehydrated, critical point dried, and coated with gold or gold/palladium. Five randomly selected sampling sites were viewed from three to five eggs for each sampling date, treatment, and incubator tray location. Each sample site was 32.5 x 42.5mm. Eggs were observed at 300x. Each micrograph was reviewed in order to record microbe levels and determine membrane condition.

Data were analyzed using analysis of variance with the SPSSS (9.0) statistical analysis program (SPSS 1999). Pairwise mean comparisons were performed using Fisher’s Protected Least Significance Difference, with significance predetermined at P<0.05 (Ott 1984). All embryo survival percentage data were arcsine transformed prior to analysis to stabilize the variances (Ott 1984).

Results

Survival was 91.0%, 90.5%, and 86.7% for hydrogen peroxide, formalin, and the control treatments respectively. We found that there was a significant difference to percent of eggs hatched between the formalin treated eggs and the control treatment. There was also a significant difference between the H202 treated eggs and the control treatment. There was not a significant difference in the percent of the eggs hatched between formal in and H202 treatments.

Mean bacterial counts from formalin treated eggs on the first day of the study were 2,075/ mm2 and were not significantly different by day 12 at 3,764/ mm2 . Eggs treated with hydrogen peroxide averaged 5,406 bacteria/ mm2 on day 1, and 6,033/ mm2 on day 7. By day 12, bacterial numbers in the hydrogen peroxide treated eggs were about 2.7 times greater than the first day of the study at 14,431/ mm2 although these means were not statistically significantly different. In the eggs receiving no chemical treatments, bacterial levels rose significantly from day 1(2,413/ mm2) to day 12(69,598/ mm2). Bacterial levels did not significantly differ by tray location within treatments.

 Discussion

All of the treatments used in our study appeared to restrict fungal growth on the egg surfaces. However, only the two chemical treatments adequately controlled bacterial populations attached to the external egg membranes. Given the significant correlation between attached bacterial numbers and embryo survival, we hypothesize that the increase in embryo survival from egg eye-up to fry hatch associated with either daily formalin or hydrogen peroxide treatments compared to handpicking alone is due to the inhibition of bacterial growth on the external egg membrane. The increased hatching success associated with chemical treatments may also be related to the bacteria observed on the surface of the eggs as reported by Barker et al. (1989).

We feel it is important for hatcheries to monitor their attached bacterial populations more closely. Because we feel that these attached microbes are linked to mortality, estimating the severity and spread of microbial populations would provide the basis for a prescribed anti-microbial treatment regime using formula or hydrogen peroxide.

We are currently investigating the use of simpler methodology involving low vacuum electron microscopy to increase the expediency and efficiency of monitoring microbe populations attached to the surface of salmonid eggs. Chemical could be increased as microbial populations increase and decreased as populations decrease, thereby reducing chemical costs and decreasing the discharge of chemicals in the hatchery effluent and environment.

 Pictures

 


Bacterial numbers per square millimeter of external egg membrane from eyed landlocked fall Chinook salmon eggs treated with either hydrogen peroxide, formalin, or no chemical treatment during incubation. Bars indicate standard error.

We would like to thank the BRIN Undergraduate Fellows Program, BHSU Nelson Grant, the hatchery spawning crews at Whitlock’s Spawning Stations, and the hatchery staff at McNenny State Fish Hatchery.