Graduation date: 2003

With aging there is a decrease in a person’s ability to perform activities of daily living (ADL) which may be most effectively addressed using training patterns that are biomechanically similar to ADL. Since aquatic exercise offers the opportunity to provide resistance with a high level of safety, the pool may afford the ideal environment for ADL-specific training in an aging population. Purpose: The purpose of this investigation was to compare a traditional aquatic exercise program (TRAD) to an aquatic program tailored to target ADL (ADLspec). Methods: Eighteen independently living individuals (68.7 + 7.5 years) were randomly assigned to a TRAD or ADLspec aquatic exercise group. The exercise groups attended 1 hr exercise sessions, 2 times per week for 8 weeks. ADL ability was assessed using the short version of the Continuous-Scale Physical Functional Performance Test (PFP-10); while strength and power were assessed using the 30s arm curl and 30 sec. chair stand tests. Results: Mixed design ANOVAs revealed a significant group x time interaction for floor sweep time with the ADLspec group outperforming the TRAD and control (CON) groups (p = .043). Additionally, the ADLspec group improved the pan weight and scarf time components of the PFP-10 (p < .020), while the TRAD group improved pan time and laundry time (p < .046). Both training groups showed similar improvements for jacket time, grocery weight, and 6-min walk, (p < .046). The ADLspec and TRAD groups also made similar improvements in upper and lower body strength, as well as lower body power across time, (p < .043). A student’s t-test revealed the TRAD group spent more time exercising during the hour session than the ADLspec group (p < .05). Conclusion: The results indicate that performing an ADLspec aquatic exercise program can increase performance of ADL that require more complex sequential movements; however, ADL more dependent on fitness may be better addressed using a TRAD intervention. These results can be helpful when designing a periodized aquatic training program to increase independence in older persons.

The field of viral ecology is still relatively new and many processes by which viruses influence hosts are still widely unknown. One problem is that there are few standardized techniques in virus ecology, making comparisons of data very difficult. To better understand the methodology, we first set out to make a video showing the process for the viral production assay using the “dilution and reoccurrence” method, which has become the standard to analyze production rates in aquatic ecosystems. Using this method, we also determined the production rates of viruses during a seasonal pelagic phytoplankton bloom during a cruise off the coast of the north island of New Zealand in the subtropical Pacific Ocean. Other biotic and abiotic parameters were also compared throughout the bloom. Production rates were within normal ranges, but showed that viruses were very important for the remobilization of nutrients in the nitrogen-limited system. It is well known that the cyanobacterial genera Synechococcus and Prochlorococcus thrive in the world’s oceans with Synechococcus and other cyanobacterial species also succeeding in freshwater ecosystems. Cyanophages are viruses which infect cyanobacteria and many studies have investigated their diversity using the portal vertex g20 gene in the Cyanomyoviridae family. Although we know that there is significant genetic richness in these phage in marine and freshwater environments, information on their numerical distributions is rare. Using quantitative PCR with the g20 gene, we determined that cyanomyoviruses are ubiquitous and abundant in the Atlantic and Pacific Oceans as well as within Lake Erie. Using statistical analyses we were able to find correlations between cyanomyoviruses and other biotic and abiotic parameters: in the Sargasso Sea, cyanomyovirus abundance correlated well to biology, but in the other systems there was no significant correlation to biological abundances. This suggests that the constraints of this group of viruses may be different in different aquatic realms.

Nutrient availability and herbivory can regulate primary production in ecosystems, but little is known about how, or whether, they may interact with one another. Here I investigate how nitrogen availability and insect herbivory interact to alter above- and belowground plant community biomass in an old-field ecosystem. In 2004, 36 experimental plots were established in which soil nitrogen (N) availability (at three levels) was manipulated and insect abundance (at two levels) in a completely randomized plot design. In 2009, after six years of treatment, I measured aboveground biomass and assessed root production at peak growth. Overall, I found a significant effect of soil N availability on both above- and belowground plant biomass while insects affected only aboveground biomass of subdominant plant species and coarse root production; there were no statistical interactions between N availability and insect herbivory for any response variable. Specifically, responses of aboveground and belowground community biomass to nutrients were driven by reductions in soil N, but not additions, indicating that soil N may not be primarily limiting production in this ecosystem. Insect herbivory altered the aboveground biomass of the subdominant plant species and altered allocation patterns to coarse root production belowground. Overall, the results of six years of nutrient amendments and insect removals suggest strong bottom-up influences on total plant community productivity.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2007. / Thesis documentation sheet inserted. Appendix reproduces five papers and manuscripts, two co-authored with others. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.

<p>Results from this study enables a better understanding of groundwater surface water interactions in the TMG, particularly regarding aquatic ecosystems. It has also highlighted the necessity to do proper impact assessments before proceeding with bulk abstraction from this important aquifer. The results also demonstrated the importance of differentiating between real groundwater and non-groundwater discharge contributions to surface hydrology and where these interface areas are located.</p>

In the spring of 2007 the Kuba Dam in Nätra Stream was removed for restoration purposes, mainly to give free passage to migrating fish. This action gave an opportunity to study the effects of dam removal on organisms both on land and in water, a type of study which is in demand for planning purposes of future dam removals. This study focuses on the effects upon the vegetation along the stream where the former reservoir was situated. Willow cuttings and sunflower seeds were used as phytometers to assess the growth conditions one year after removal at three different elevation levels at four different sites along the Nätra Stream. The reaches studied were the former reservoir of Kuba Dam (Site A), the area just downstream of this former dam (Site B), further upstream in the reservoir of the existing Nyfors Dam (Site C), and even further upstream at Myreforsen, a reference area not affected by dams (Site D). Willow cuttings and sunflower seeds were planted at three different riparian levels at the sites in June and left to grow until August when growth results were collected. Many of the cuttings had died but statistically significant differences between sites could still be detected. They showed that the former reservoir shorelines in Kuba (Site A) had a plant growth significantly higher than the other regulated site. In other words, it was no longer equal to an existing reservoir but not yet similar to a free-flowing reach. The western side of the stream at this site had a higher growth than the eastern side and also higher than all the other sites. As for the three levels, the results showed a higher growth at the lowest elevation level at site A than all at the other levels and sites. This suggests that a combination of good access to sunlight and nutrients and fine-grade moist substrate results in a good growing conditions nearer the water in this former reservoir. The results for the sunflower seeds showed that the reference reach had a higher colonization success than the other sites. / Utrivningen av Kubadammen i Nätraån våren 2007 gav möjlighet att studera och följa upp hur en sådan förändring påverkar organismer på land och i vatten både uppströms och nedströms den tidigare dammen. Denna typ av undersökningar efterfrågas allt mer i och med att fler och fler dammar rivs av olika anledningar. I Kubadammens fall hade dammen förlorat sin ursprungliga roll och de fördelar som magasinet förde med sig för bland annat rekreation vägde inte längre upp dämningens negativa effekter på vattendragets ekosystem, till exempel som vandringshinder för fiskar. I denna studie har fokus lagts på vad som sker med vegetationen på stränderna längs det forna vattenmagasinet efter rivning. Med hjälp av videkvistar och solrosfrön som fytometrar undersöktes tillväxten ett år efter rivning på tre olika strandnivåer på fyra olika lokaler längs Nätraån. Dessa lokaler var Kubadammens gamla magasin (Lokal A), området direkt nedströms den före detta dammen (Lokal B), den nuvarande Nyforsdammens magasin (Lokal C) uppströms den före detta dammen, samt en referenssträcka vid Myreforsen (Lokal D) uppströms alla Nätraåns dammar och därmed ej påverkad av dämningseffekter. Videkvistarna och solrosorna planterades på tre nivåer på de olika lokalerna i juni och tilläts växa till augusti då tillväxtresultaten samlades in. Många kvistar hade dött under tiden men tillräckligt många överlevde för att det skulle gå att läsa ut statistiskt signifikanta skillnader i tillväxt. Resultaten visade att det före detta magasinet vid Kuba (Lokal A) hade en signifikant högre tillväxt än de andra lokalerna, vilket visar på att tillväxtförhållandena för vide varken liknar dem i ett befintligt magasin eller på en orörd sträcka eller nedströmssträckan, utan var betydligt mer gynnsamma. På denna lokal växte fytometrarna dessutom signifikant bättre på den västra sidan än på den östra sidan. När man ser till de tre nivåerna så växte videkvistarna i nivån närmast vattnet i det före detta magasinet vid Kuba bättre än på de övriga nivåerna på samma lokal och på de övriga lokalerna. Troligtvis beror detta på en kombination av öppenhet som ger bra tillgång till solljus, bra näringstillgång, substratets finkornighet och förmåga att hålla kvar fukt närmare vattnet. Resultaten av solrosfrönas etablering visade på att referenssträckan hade en högre etablering än övriga lokaler.

Although there is much theoretical and empirical data about the life history responses of time constrained organisms, little is known about the latitude compensating mechanism that enables northern populations’ developmental rates to compensate for latitude. To investigate the importance of photoperiod on development and growth, I collected adults and raised the offspring of the obligatory univoltine damselfly Lestes sponsa from two populations at different latitudes (53º N and 63º N). The offspring were raised in a common laboratory environment at 21º C and at the two photoperiods corresponding to the sites of collection. Field data showed that adult and egg sizes decreased towards the higher latitude. This adult size difference was a genetically fixed trait since the same size difference between populations was also found when larvae where reared in the laboratory. All studied individuals expressed shorter development time and faster growth rates under northern photoperiod regimes. Northern damselflies showed fixed body size and mass at emergence despite being reared at different photoperiod conditions. Similarly, southern individuals kept body size at emergence constant at both photoregimes, but overcompensated shorter development time in the northern photoregime by gaining higher body mass than in original,southern photoregime. There was no difference in hatching synchronisation between larvae from the south and the north. I found evidence of higher synchrony at adult emergence among northern individuals. The previous investigation of L. sponsa phenology in natural conditions together with these laboratory results indicate the presence of the latitude compensating mechanism that is triggered by a response to photoperiod. A positive correlation between photoperiod and developmental rate in this damselfly, and probably in many other temperate insect species, might be adaptive since it optimises the life history stage transitions and body size/mass at each latitude.

No description available.

Along the Toronto shoreline, small coastal embayments (0.4 – 32 ha) are being constructed or modified to restore warmwater fish habitat. I describe how Lake Ontario (hereafter the Lake) alters the thermal regime of these small coastal embayments, how the altered thermal regimes affect growth and survival of age-0 warmwater fishes, and how the thermal habitat quality for such fishes can be improved by altering embayment design. During the warming period of the ice-free season, embayments warm faster than the Lake and so are cooled by exchanges with the Lake. Later in the year Lake exchange warms the rapidly cooling embayments, but the net effect of Lake-embayment exchange is cooling. The degree of cooling in Toronto’s small coastal embayments varies; many have temperatures near that of the Lake, and a few warm as much as local ponds. Age-0 pumpkinseed (Lepomis gibbosus) can fail to reach sufficient size to survive the winter in cooler embayments because their spawning is delayed and their growth is slowed. Most embayments along the Toronto shoreline are too cold to produce age-0 fish that can survive the winter, but all embayments are occupied by age >1 pumpkinseed, suggesting movement from warmer to cooler embayments. Using otolith microchemistry to identify natal embayments of fish, I confirm that age-0 and age-1 pumpkinseed, as well as age-0 largemouth bass (Micropterus salmoides) and age-0 yellow perch (Perca flavescens), exist in metapopulations. Embayment bathymetry is a poor predictor of temperature because almost all embayment flushing rates are very fast, usually 1-2 days. Warmer embayments are located in protected areas of Lake Ontario and receive waters that have already heated substantially. Cold embayments are located along the exposed shoreline of Lake Ontario. To protect embayments from cold lake waters, the cross-sectional area of embayment channels need to be reduced to 1-10% of their current size.