Prevalence of Batrachochytrium dendrobatidis (Bd) within the Eastern Newt (Notophthalmus viridescens) Population in Lynchburg, Virginia

Undergraduate Basi

Prevalence and Infection Intensity of Fungal Pathogen Batrachochytrium Dendrobatidis in the Eastern Newt (Notophthalmus viridescens) in Relation to Seasonal Change

Undergraduate Basi

Efficiency of Strongylocentrotus franciscanus in extracting calories from algal foods: implications for benthic communities.

Algal subsidies are extremely important to the success of the deep benthos where there is little to no primary productivity. Little research has been done on the nutritional value of detritus, such as pieces of kelp, sinking into deep habitats. Sea urchin feces, in the form of detritus, may provide an energetic link to benthic communities with no primary productivity. Urchins are known to have an inefficient digestive system which leaves the potential for high food value in feces. I conducted a series of tests on the relative caloric contents of algae and urchin feces. First, I measured the biomass consumed and egested by urchins. Secondly, I quantified the caloric content of aged and fresh feces of 10 urchins fed diets of either Nereocystis luetkeana or Saccharina latissima. For both kelp diets, the caloric content of algal material increased after being consumed by urchins, and the longer the urchin feces aged, the higher the caloric value became. This could be significant in considering the importance of urchins as a link to benthic communities that rely heavily on detritus for their success

The role of flow in determining zooplankton populations inside and outside kelp beds near the San Juan Islands.

This study explored the relationship that flow in Nereocystis luetkeana beds has to zooplankton communities in the San Juan Islands. The hypothesis was that current flow rates would decrease further inside a kelp bed and that this would affect the types and densities of zooplankton. More Calanoid copepods were expected outside of the beds and more larval organisms inside the beds. Flow rates were measured by attaching blocks that dissolve over time to kelp at the center, edge and outside the kelp bed and comparing the changes in weight. Zooplankton sampling was done with a water pump and net. Results were statistically inconclusive due to small sample size and difficulty in retrieving blocks. There were possible connections between the rate of flow and the differences in zooplankton communities in and out of kelp beds at different sites. Lower velocity sites appear to have more different communities in and out

Hoins 1 Efficiency of Strongylocentrotus franciscanus in extracting calories from algal foods: implications for benthic communities

Algal subsidies are extremely important to the success of the deep benthos where there is little to no primary productivity. Little research has been done on the nutritional value of detritus, such as pieces of kelp, sinking into deep habitats. Sea urchin feces, in the form of detritus, may provide an energetic link to benthic communities with no primary productivity. Urchins are known to have an inefficient digestive system which leaves the potential for high food value in feces. I conducted a series of tests on the relative caloric contents of algae and urchin feces. First, I measured the biomass consumed and egested by urchins. Secondly, I quantified the caloric content of aged and fresh feces of 10 urchins fed diets of either Nereocystis luetkeana or Saccharina latissima. For both kelp diets, the caloric content of algal material increased after being consumed by urchins, and the longer the urchin feces aged, the higher the caloric value became. This could be significant in considering the importance of urchins as a link to benthic communities that rely heavily on detritus for their success

Feeding Preferences of Red Urchins, Strongylocentrotus franciscanus, to Drift Kelps

Kelps and major contributors to primary production in temperate marine ecosystems. Kelps also make up a high amount of biomass and provide structure and habitat to many organisms. However, little kelp biomass is directly consumed. However, its biomass is transported via a spatial subsidy. This spatial subsidy links near-shore primary production with comparatively deep water primary consumers. One such consumer is the red sea urchin, Strongylocentrotus franciscanus. Urchins are known to feed on kelps transported by the spatial subsidy. These drift kelps may spend weeks drifting and degrading before they are encountered by an urchin. There has been little research on how the degradation or aging of kelps has on palatability to urchins. This study tests the feeding preference of red urchins to three species of kelp (Nereocystis luetkeana, Agarum fimbriatum, Saccharina subsimplex) that were both fresh and aged with the hope of gaining insight to how kelps move through the spatial subsidy. We also investigated how phlorotannin content changes as kelp age. Some research suggests that phlorotannins act as herbivory deterrent and that as kelp age they lose their phlorotannins. We found that Nereocystis luetkeana was the most preferred kelp species and that fresh kelps were preferred over aged ones. Analysis of phlorotannin content showed that there is a difference between species in phlorotannin content but the data suggests that there is little to no change through time. Further analysis indicated that urchins can detect the differences between kelps. This may mean that urchins act as a biological filter to detrital kelps as they are moved through the spatial subsidy and integrated into the food web

The role of flow in determining zooplankton populations inside and outside kelp beds near the San Juan Islands.

This study explored the relationship that flow in Nereocystis luetkeana beds has to zooplankton communities in the San Juan Islands. The hypothesis was that current flow rates would decrease further inside a kelp bed and that this would affect the types and densities of zooplankton. More Calanoid copepods were expected outside of the beds and more larval organisms inside the beds. Flow rates were measured by attaching blocks that dissolve over time to kelp at the center, edge and outside the kelp bed and comparing the changes in weight. Zooplankton sampling was done with a water pump and net. Results were statistically inconclusive due to small sample size and difficulty in retrieving blocks. There were possible connections between the rate of flow and the differences in zooplankton communities in and out of kelp beds at different sites. Lower velocity sites appear to have more different communities in and out

Kelp Detritus Provides High-Quality Food for Sea Urchin Larvae

Highly productive kelps release abundant particulate organic matter into the nearshore environment due to their constant fragmentation and erosion by ocean waves. The contribution of kelp detritus to coastal planktonic food webs has not previously been examined. Here, we demonstrate that detritus derived from a dominant kelp in the Northeast Pacific, Nereocystis luetkeana, provides high-quality food for planktonic sea urchin larvae. Our findings challenge the paradigm that phytoplankton are the main diet for zooplankton in nearshore regions, with implications for modeling of ocean production. Furthermore, at the benthic adult stage, sea urchins can destructively graze kelps causing the kelp ecosystem to collapse; hence, our results have implications for understanding feedback mechanisms that may determine the resilience of kelp ecosystems