ALBERT

Description: In September 1994, Shuttle Orbiter Discovery, STS-64, launched into space. Aboard that shuttle was a payload containing Fungi spores, genus Penicillium. With the over looking help of Dr. Audrey Gabel, Associate Professor of Biology at Black Hills State University, investigations on differing media types began. Basis for this experimentation was to determine if there was any differences between the space exposed spores and control spores. Studies concluded that there were differences and those differences were then recorded. It was hypothesized the spores may have been effected causing differences in growth rate, colony size, depth and margins, coloring, germination, and growth on different media.

Description: Wake vortices from a C-130 airplane were observed at the NASA Wallops Flight Facility with a ground-based, monostatic C-band radar and an antenna-mounted boresight video camera. The airplane wake was viewed from a distance of approximately 1 km, and radar scanning was adjusted to cross a pair of marker smoke trails generated by the C-130. For each airplane pass, changes in radar reflectivity were calculated by subtracting the signal magnitudes during an initial clutter scan from the signal magnitudes during vortex-plus-clutter scans. The results showed both increases and decreases in reflectivity on and near the smoke trails in a characteristic sinusoidal pattern of heightened reflectivity in the center and lessened reflectivity at the sides. Reflectivity changes in either direction varied from -131 to -102 dBm(exp -1); the vortex-plus-clutter to noise ratio varied from 20 to 41 dB. The radar recordings lasted 2.5 min each; evidence of wake vortices was found for up to 2 min after the passage of the airplane. Ground and aircraft clutter were eliminated as possible sources of the disturbance by noting the occurrence of vortex signatures at different positions relative to the ground and the airplane. This work supports the feasibility of vortex detection by radar, and it is recommended that future radar vortex detection be done with Doppler systems.

Description: Investigations of factors affecting feeding success in fish larvae require knowledge of the scales of variability of the feeding process itself and the indices used to assess this variability. In this study, we measured short-term (diel) variability in feeding rates of wild haddock (Melanogrammus aeglifinus) larvae four times per day during a 10-d cruise in the northern North Sea. Feeding activity was evaluated using indices of gut fullness, prey digestive state and biochemical measurements (tryptic enzyme activity). The gut fullness and the enzyme activity indices indicated moderate to high rates of food consumption throughout the cruise. Time series analysis of the three indices showed significant diel variability in all indices and enabled identification of significant lags between food uptake and peak digestive enzyme activity. The typical pattern of food consumption and digestion was characterized by maximal ingestion of prey early in the evening (19:00 hrs) and peak digestive enzyme activity at 01:00 hrs. The time scale over which enzyme activities reacted to prey ingestion was ca. 6 h, and is consistent with expectations from controlled laboratory experiments with other larval fish species. Significant diel variability in tryptic enzyme activity suggests that attempts to relate this measure of feeding success to other variables (e.g. food concentrations) should take care to accommodate natural cycles in feeding activity before making statistical comparisons.

Description: The volume of water with suitable oxygen and salinity conditions for survival and development of cod/eggs in the eastern Baltie Sea varies significantly within and among years. It has recently been shown that this volume of water (nreproduetive volumen), in addition to spawning stock biomass, is a major factor determining recruitment success in this eod population. However, it is unclear which oceanographie mechanisms are responsible for variability in reproductive volume, and how these processes interaet on a seasonal and interannual basis. In this study, we use time series observations to identify inter-relationships between hydrographie and biological processes (e. g., inflows of North Sea water, winter mixing processes, production and decomposition of organic matter) influencing reproductive volumes from 1952-1992. A frequent pattern of seasonal variability in 4 eastern Baltic spawning areas includes a spring maximum which decreases during the summer, followed by an inerease during the fall-winter months. However, this general pattern is violated in many years, and the magnitude of the seasonality is more pronounced, in some spawning areas than others. \Ve have begun to analyse these patterns and interpret them in the context of other fluctuating components of the eastern Baltic pelagic ecosystem. Preliminary results show that reproductive volumes deerease by an average of 9 - 39% between May and August, and that the decrease in the spawning area most important to long-term recruitment (Bornholm Basin) is temperature-dependen1. The seasonal decline in the Bomholm Basin also tends to be larger and more variable after 1964 than in the previous 12-year periode These patterns of reproductive volume variability may be important to eod reproduetive success beeause of a long and variable spawning period.

Description: Investigations of factors affecting feeding success in fish larvae require knowledge of the scales of variability of the feeding process itself and the indices used to assess this variability. In this study, we measured short-term (diel) variability in feeding rates of wild haddock larvae 4 times per day during a 10-day cruise in the northern North Sea. Feeding activity was evaluated using indices of gut fullness, prey digestive state and biochemical measurements (tryptic enzyme activity). The gut fullness and the enzyme activity indices indicated moderate-high rates of food consumption throughout the cruise. Time series analysis of the three indices showed significant diel variability in all indices and enabled identification of significant lags between food uptake and peak digestive enzyme activity. The typical pattern of food consumption and digestion was characterized by maximal ingestion of prey early in the evening (7 pm) and peak digestive enzyme activity at 1 am. The timescale over which enzyme activities reacted to prey ingestion was ca. 6 hours and is consistent with expectations from controlled laboratory experiments with other larval fish species. Significant diel variability in tryptic enzyme activity suggests that attempts to relate this measure of feeding success to other variables (e. g., food concentrations) should take care to accommodate natural cycles in feeding activity before making statistical comparisons.

Description: Variations in oxygen conditions below the permanent halocline influences the Baltic ecosystem through a number of mechanisms. Principle among these are fluctuations in the availability of benthic habitat suitable for Baltic cod (the top predator in the Baltic ecosystem). Variations in the volume of deep oxygenated water influences dircetly the potential feeding habitat and volume of water suitable for spawning. Recent research has identified the importance of inflows of saline, oxygen rich North Sea water into the Baltic sea on the recruitment success of Baltic cod. These inflows increase the volume of water with suitable oxygen and salinity conditions for the development and survival of cod eggs (termed spawning volume). Increases in the "spawning volume" have occurred with out the occurrence of a major inflow from the North Sea (e.g. 1958-59; 1966-67). Other candidate processes suggested to potentially increase the "spawning volume" include variations in timing and volume of terrestrial runoff, advection of water from the Arkona Basin, convective overturning of the water column due to surface cooling as well as wind mixing down to the halocline. In order to examine the latter three mechanisms, we have performed model simulations utilizing the Baltic Sea Model (Lehmann, 1995). Three-dimensional fields of temperature and salinity were obtained from field studies in July 1995 and interpolated onto the model grid, atmospheric forcing data was obtained from EUROPA-Model. The BaItic Sea model was then run from the period from July 24 to December 31, 1995. To test the effects of increased wind energy and surface cooling on oxygen conditions below the permanent halocline variations in the oxygen conditions were examined utilizing the following experiment conditions; a) a reduction of SST by 5 oe over the entire simulation period thereby increasing vertical convection. b) an increase of surface wind energy over the modeled period by 15%. c) two high energy winter storms The results of these simulations and the possible implications of the effects of these processes on the reproductive environment of Baltic cod will be discussed.