Examining the costs of herbicide resistance on the growth of Ceratopteris fern (C-fern)

In this study, we examined the effects of herbicide resistance on the growth of the Ceratopteris fern (C-fern). Herbicide resistance and tolerance to abnormal soil conditions (e.g., high metal content) ahs been observed in a number of plant species (Harper 1997, Holt 1988). Despite the advantages that resistance can incur to the plant, resistance also results in some costs to the organism. In this study, we aimed to document and quantify the costs of resistance to herbicide in the C-fern. Genetically modified C-ferns resistant to glyphosate (a common herbicide) and non-resistant wild-type C-ferns were grown on nutrient agar plates under controlled conditions. To one half of the plates containing resistant plants and to one half of the plates containing non-resistant plants, a 0.1% glyphosate solution was applied following two weeks of growth. After 5 days, the relative fern size was determined by photocopying the plates and weighing the paper replica of each individual fern. The data was analyzed using Statview to generate a two-way ANOVA. Growth was not affected by presence or absence of treatment with glyphosate (p=0.9915). Genotype affected growth significantly (0.0187), and non-resistant plants grew to a bigger size than resistant plants. The cost of being resistant was a 15.5% decrease in growth.

Measurements of Growth in a Legume and Non-Legume: An Investigation on the Effects of Competition in Varying Densities

Tanner Savage and John Butz

Nitrogen is an integral aspect of a plant's life as it enhances growth. Our experiment was designed to examine the effects of grass on a legume and a non-legume plant species when in competition for nitrogen. Conducting the experiment with different density levels of grass, the following question was posed: How does the mass of the target plant species vary with an increasing neighbor density? With the legume able to fix its own nitrogen, a larger target mass for the legume species was expected. Eighty-eight pots were planted with either a legume or non-legume. Densities varied between zero neighbor seeds and ten neighbor seeds per pot. Watering was performed twice a week with all other abiotic factors kept constant. The plants were grown over a five-week period after which they were cut, dried, and weighed. Results showed that an increasing neighbor mass had a negative effect on the target mass (p=0.0102). Comparison between the two target species masses and the neighbor density yielded different results. Results showed density had no significant effect on the non-legume target mass (p=0.03531) while density did have a significant effect on the legume target mass (p=0.0392). The negative effect of neighbor mass on target mass was expected as competition for nutrients was occurring. The effect of density on the target species was opposite of what we hypothesized. Competition between the legume and the grass for a nutrient different than nitrogen may have affected the legumes growth where as the non-legume may not have competed at all with the grass and therefore showed no signs of competition. Testing other legume and non-legume species versus density would be a plausible next step which may support or refute our results.

 

Is Invasion of English Ivy Limited by Light?

Jake Goodchild and Shannon Zamani

English ivy (Hedera helix) is one of the most insidiuous and invasive plants threatening all levels of forest from the ground to the canopy. It kills native ground cover by obstructing light; also the weight of the vines makes trees susceptible to falling over in storms as well as being a reservoir of plant pathogens. We hypothesized that ivy does not usually go into canopy because light levels are not in its realized niche. Our study looked at the effects of light levels on the biomass of Hedera helix presupposing that the higher light levels will have less growth. 50 control and 50 treatment cuttings were obtained at Point Defiance; wet weights were then taken. The control cuttings were dried, weighed, and a regression line was found comparing wet and dry weights (R^2 = 0.584). The treatment cuttings were placed in 50 separate pots in rows of ten. Each row was assigned a shade level ranging from no shade to 4 layers of shade. After 45 days, the cuttings were removed, dried and weighed. An ANOVA test showed no significant correlation between the shade levels and the net change in dried biomass (p=0.2597) and a Fisher's test showed that the different shade levels did not significantly alter growth. We conclude from these results that English ivy's realized niche does not discriminate according to light levels we provided. Our results may have supported our hypothesis had there been a significantly longer growing period. This accounted for, it is logical that our results are such since the ivy is such a threat. Other experiments may include testing its water requirements, temperature preferences, and competition ability to identify its realized niche.

 

Effect of Eradicating Invasive Species on Native Plant Species in Puget Creek Trough

R. Matthew Blair and John Morgan

As the long term effects of habitat degradation come into light, an increasing focus on habitat restoration has led people such as Scott Hanson of Tacoma to lead restoration projects such as those at Puget Creek Park. Though at this point long term effects may be only speculated, short term effects provide useful feedback to improve methods of habitat conservation and regeneration. We set out to examine the response of salmonberry (Rubus spectabilis) and Indian plum (Oemleria cerasiformis) to the eradication of invasive species (mainly Himalayan blackberry, Rubus discolor), hypothesizing that if invasive species were eradicated then native species would do better. We predicted that where invasive species had been removed, growth would significantly increase, so we measured apical stem growth on 15 Indian plum and 50 salmonberry specimens in sites where invasive species had been cleared zero, 2, 3, and 4 years ago. We found that cleared sites experienced more salmonberry and Indian plum growth last year than the site where invasive species had not been cleared (p<0.0001), supporting our hypothesis that native species are benefiting from eradication of invasive species. We suggest that further research investigate population response in addition to individual plant response to eradication.

 

A Study of Marine Colonization of Surfaces of Different Orientations in the Spirit of Island Biogeography

Luke Grange and Liana Cabiles

The purpose of this study was to examine the distribution of marine species on surfaces of three different orientations&emdash;horizontal, vertically sloped, and vertical&emdash;using the 1) number of acorn barnacles present and 2) biomass. Our findings are taken to be an indication of the diversity of the various marine species present and their affinity for surfaces of different orientations located in the Puget Sound of Tacoma, Washington. After two flower pots were submerged in the Puget Sound for eight weeks, the number of acorn barnacles located on each surface was counted. The dry mass of all organisms living on each of the three surface orientations was then taken. These numbers were then normalized for their surface areas to account for the differing sizes of the surfaces. Because the data was not replicated (only two flower pots used in our study), a chi-squared test was performed. We found a significant number of acorn barnacles on the horizontal and vertical surfaces of flower pot #2 different from would be expected. The horizontal surface was significantly lower in acorn barnacle individuals than would be expected if no other factors were at work here; the vertical surface was significantly higher. No significant differences were found between acorn barnacles or biomass on the different surfaces of flower pot #1. Surface orientation is significant for acorn barnacle colonization, our study concludes, though how significant may depend on the location studied.

 

Optimal Foraging in Evasterias troschelii: Selection of Mytilus trossulus and Mytilus galloprovincialis

Joy Gibson and Anne Johnston

Studies have shown that starfish preferentially choose mussels as their prey. This is significant for the maintenance of biodiversity in intertidal zones because without starfish predation, mussels would outcompete barnacles. This study focused on the starfish Evasterias troschelii. In order to determine most profitable mussel size, biomass and time to open for mussels of various sizes was measured. We expected to find a mussel size with a maximum profitability (calculated as biomass per time to open). Then, we monitored feeding patterns of five starfish with mussels of four size classes (tiny, small, medium, and large) to determine whether starfish were foraging optimally. Starfish selectively chose small mussels over large mussels and had no significant preference among other size classes. Although we did not genetically analyze the mussels, the larger mussels may have been a different, invasive species (Mytilus galloprovincialis). Thus, the selection of smaller mussels may be species related. There was no significant variation in time required to open various size mussels or a relationship between amount of force applied and time to open. However, biomass significantly increased with mussel size. This suggests that there is some other factor that plays a role in starfish selectivity because they did not choose the mussels with the largest biomass. Future experimentation could seek to determine specific feeding mechanisms of the starfish, conduct genetic testing of mussels and compare starfish feeding on different species, or expand sample size for each of our experiments.

 

Behavioral Analysis in Crickets: Does Temperature Affect the Frequency of Chirps in Acheta domesticus?

Libby McDonald and Maria Jost

Environmental variables affect behavioral patterns of many organisms, influencing how they interact with other species and their ecosystems. Determining what factors influence the behavior of an organism can reveal information about its habits and ideal surroundings. Crickets chirp to attract mates, a behavior important to their survival. We investigated cricket behavior in different settings in order to determine whether temperature affects the rate of chirping. We hypothesized that the rate at which crickets chirp is determined by the surrounding temperature, predicting that as temperature increased, the frequency of chirping would increase also. In order to test the effects of temperature, we placed approximately 500 Acheta domesticus (field crickets) in an aquarium and varied the surrounding temperature, keeping other variables such as light and food levels constant. We then measured the number of chirps per minute in the various temperatures. We statistically analyzed the data using a regression test. Our data showed that temperature had a positive effect on the rate of chirping (p<0.0001), confirming our prediction. This leads us to conclude that our hypothesis was supported, as temperature was the varying factor and thus the probable cause of the change. Although the data seem to support our hypothesis, other factors that we did not measure such as humidity and time of data collection may have affected the crickets' behavior. If future testing was to be done these variables should be taken into account.

 

Do barnacles adapt to salinity fluctuations?

Bryan Brune, Joe Boice, and Frank Reed

In this experiment, we wanted to know how the salinity of water affected Balanus spp. Wellness and whether or not these barnacles had developed any tolerance of lower salinity than that of normal seawater's (30-32 ppm). Answers to these questions would help people in the future to conserve barnacles if the time ever came that these barnacles were troubled or if they needed to be cared for in captivity. Our hypothesis to our first question was that the lower the salinity was the worse the wellness of the barnacles would be. To run our experiment we collected barnacles from Fox Island and from a watershed close by the Puyallup River that drained into Commencement Bay. The barnacles from each site live in different salinities and were placed in aquariums with the salinity of Fox Island, (30 ppm), and that of the watershed, (10 ppm). For three weeks, the wellness of the barnacles was measured via their feeding rates. The feeding rate was determined by how many beats were done by the barnacles' cirri per minute. The data showed that, overall, the lower the salinity the slower the feeding rate (p<0.0001). However, we had disagreements in our data from the barnacles from the watershed. Data said that salinity did not affect their feeding rate; however, there were speculations on how healthy those barnacles were before the experiment began. In the future, with a few changes, this experiment could be used to look at different factors affecting barnacles wellness such as light, exposure to air, competitors, and predation.

 

The Effect of Herbivory on the Biomass of Grass

Kaitlin Weideman and Natasha Nicolai

Grass is commonly found surrounding houses, businesses, and schools. It is not uncommon for grass to be watered, trimmed, and fertilized in order to maintain healthy lawns. This study focusis on the actual benefit of cutting grass (herbivory) that is both fertilized and unfertilized. It is generally accepted that cutting grass allows it to become more healthy because more light is allowed to strike the basal maristem. The alternative hypothesis presents the photosynthetic tissue of grass as more important to its ultimate health in which case, cutting the grass would not improve its health or fitness. Health in this experiment was measured by plant biomass. Three sets of manipulated lawns of perennial ryegrass (Lolium perenne) and one control were used to accumulate the data. Soil for two sets contained slow releasing fertilizer maintaining a high level of nitrogen over the course of the experiment. The other two sets of lawns were not treated with fertilizer. One of the two set from both the high and low nitrogen groups was cut every four days for a month, and the grass clippings dried and weighed. At the end of one month, the other sets were cut and the grass clippings dried and weighed. The total biomass accumulated for the uncut lawns was higher than the lawns cut throughout the experiment. Additionally, the total biomass accumulated by the lawns treated with fertilizer was higher than the lawns grown on normal potting soil. A two-way ANOVA test to compare the effects of fertilization and herbivory was completed. The results showed the biomass of uncut lawns to be significantly higher than lawns cut frequently (p<0.0001). Fertilizer however did not significantly increase the health of grass on its own or when combined with herbivory (p=0.282, p=0.067). Further tests dealing with frequency of cutting and amount taken with each cut could show that less frequent herbivory, or herbivory in different balances with fertilization is actually beneficial to grass, increasing its health.

 

The Response of Anthopleura to the Presence of Water Circulation

Shelley Cook and Katie Heaton

Anthopleura are passive suspension feeding sea anemones, meaning they do not move themselves to search for food; they wait for the food to pass by, by current or self-propulsion, and "catch" the food with their tentacles. Their tentacles contain sensory cells that are also present around the mouth. Each sensory cell contains a flagellum, which serves as a chemical and tactile sensor. Sea anemone are capable of moving; however, they move very slowly, via a pedal disc that is semi-permanently attached to the chosen substrate. This experiment was designed to examine the movement of sea anemones, to determine if they have a tendency to move towards an area of stronger water current, where food can be passed freely through the anemone's tentacles or if the chemical stimulus provided by food is what causes them to move. We used two separate 5 gallon aquariums that were partially divided in two equal halves, in the experimental tank, a water circulator was placed on one side. Eleven Anthopleura started on one side of each tank (the side without the circulator in the experimental tank) and movement was monitored every 8 hours for three days. We hoped to find that significantly more anemones moved under the partition towards the circulator than the one without. We used the Chi-square test and found that the number of anemones that moved under the partition towards the circulator was not significantly different (p>0.9999) than the number that moved randomly under the partition in the control tank. This indicates that Anthopleura do not respond to water circulation. Further experiments include seeing if anemones respond by movement to food, as well as repeating this experiment with a larger sample size to see if the anemone will randomly disperse throughout the tank in the presence of a partition.

 

Are Rock Shelters a Limited Resource for Shore Crabs?

Jenny Elwell and Tricia Howard

When glancing at the rocky shore of the Puget Sound, many would not believe the amount of life that is living there. Underneath these rocks lie thousands of shore crabs (Hemigrapsus spp.), as well as many other organisms. One might ask why a crab would hide under a particular rock. The larger the rock, the more room a crab would have, and thus less competition. We predicted that larger rocks would house a larger crab population. To test this, various sized rocks were flipped over on a beach by Ruston Way, and the shore crabs were collected in a bucket. Both size and sex of each crab were recorded, as well as the size of the rock itself. Four tests were then run on the data in order to test the effect of the area of the rock on the total number of crabs, the total area of the crabs, the percentage of the crabs that were female, and the percentage of the total area of the crabs that was made up by female crabs. It was found that while gender did not have any effect on the number of crabs housed beneath the rocks, there was a direct relationship between rock area adn the total number of crabs under the rock (p=0.0008) as well as the total area of crabs housed under the rocks (p=0.0003). A possible further study would be to test the effect of the crab species on the number of crabs found under the rocks.

 

Competition between Funaria hygrometrica and Bryum argenteum in Controlled Environments with High and Low Nutirent Availibility

Meg Amaral and Jes Werner

When organisms are competing for a resource, the needs of some organisms will not be fully met. For our study, we grew the mosses Funaria hygrometrica and Bryum argenteum together and separately in agar with different nutrient concentrations to determine whether the two species were competing for nutrients. We hypothesized that one or both of the species would do better than the other when grown together. We planted 24 samples of each of the six conditions: Funaria and Bryum separately and together at both high and low nutrient concentrations. Our results indicate that the concentration of nutrients does significantly affect moss growth (p=0.0177), and that growing the two species together significantly affects growth (p<0.0001). We also found that the growth of the two species of moss was significantly different (p=0.0017). From these results, we can conclude that Funaria and Bryum were competing for nutrients, and that Funaria out-competed Bryum at both nutrient levels&emdash;suggesting that Funaria is a better competitor. We feel that the next step would be to observe moss species grown together for a longer duration in order to determine if Funaria would completely out-compete Bryum. We would also like to investigate a method of determining biomass that did not involve removing the moss form the agar, in order to track biomass changes over time.