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Articles 1 - 5 of 5
Full-Text Articles in Life Sciences
The Role Of Water Motion In Algal Reproduction, Richard Gordon
The Role Of Water Motion In Algal Reproduction, Richard Gordon
Electronic Theses and Dissertations
Environmental conditions, such as water motion, can influence fertilization success and spore dispersal in marine algae. Previous studies on fucoid algae showed that gamete release is restricted to, or enhanced by, periods of low water motion. Few other algal taxa have been investigated, however, including species with an alternation of generations. I investigated gamete and spore release in the macroalgae Alaria esculenta and Ulva lactuca, as well as in the diatom Pseudo-nitachia multiseries to determine if water motion is inhibitory or stimulates propagule production and release. I used orbital shakers to simulate water motion; these were interspersed with stationary platforms …
Chemosensory-Mediated Deposit Feeding In The Spionid Polychaete Dipolydora Quadrilobata., Timothy J. Riordan Jr.
Chemosensory-Mediated Deposit Feeding In The Spionid Polychaete Dipolydora Quadrilobata., Timothy J. Riordan Jr.
Electronic Theses and Dissertations
Deposit feeding organisms live and feed in marine soft-sediment habitats. This sediment makes up a majority of the material ingested by deposit feeders and contains a variety of edible material that may constitute their principal nutrient source. However, the specific components that are assimilated by these organisms, and the strategies they employ to efficiently collect those components, remain unclear. Sensory interactions between an organism and its surrounding environment typically play an important role in helping the organism detect and locate potential food. Accordingly, chemical sensing by deposit feeders is most likely involved in feeding, yet few specifics about this role …
The Response Of First And Second Order Streams To Urban Land-Use In Maine, U.S.A., Chandler Morse
The Response Of First And Second Order Streams To Urban Land-Use In Maine, U.S.A., Chandler Morse
Electronic Theses and Dissertations
Physical, chemical, and biological characteristics of streams draining 20 catchments in Maine, U.S.A were compared to determine the influence of increasing urban intensity on stream ecosystem structure. The catchments had varying levels of urban land-use (percentage of the total impervious area within the catchment) ranging from 1-31%. Stream habitat quality, stability, and water quality consistently decreased as the proportion of impervious surface area increased within the catchment. .Indices based on stream benthic macroinvertebrate communities showed even stronger declines as a function of increasing impervious area in the study catchments. Streams draining catchments with levels of impervious surfaces <6% had higher levels of both total and Ephemeroptera + Plecoptera + Trichoptera (EPT) taxonomic richness. With increased levels of urban intensity, benthic macroinvertebrate communities in streams were characterized by decreased numbers of sensitive taxa. Taxa considered to be moderately sensitive to anthropogenic stress (e.g. Acerpenna (Ephemeroptera), Paracapnia …
Evolution Of An Oxygen-Binding Hemoprotein In A Unique Environment: Myoglobin In The Hemoglobinless Antarctic Icefishes, Bruce D. Sidell
Evolution Of An Oxygen-Binding Hemoprotein In A Unique Environment: Myoglobin In The Hemoglobinless Antarctic Icefishes, Bruce D. Sidell
University of Maine Office of Research Administration: Grant Reports
For approximately the last 40 million years, a unique fish fauna has been evolving in the frigid seas surrounding Antarctica. Physiological function of these water-breathing animals has demanded many adaptations to ensure proper metabolism and regulation of biochemical processes at cell temperatures of about OoC. Among the polar fishes, one family is particularly unusual, the Channichthyid icefishes. Species in this family lack hemoglobin in their circulating blood and, at least the majority, do not possess the intracellular respiratory protein, myoglobin, that is normally responsible for enhancing movement of oxygen through aerobic muscle tissues. The PI's have recently found two species …
Mechanisms By Which Marine Algae Respond To Environmental Variables Affecting Reproductive Success, Susan H. Brawley
Mechanisms By Which Marine Algae Respond To Environmental Variables Affecting Reproductive Success, Susan H. Brawley
University of Maine Office of Research Administration: Grant Reports
Many marine species reproduce by external fertilization. This mode of reproduction might be expected to result in low levels of fertilization and recruitment because of the dilution of eggs and sperm by the turbulent sea. Recent work, however, demonstrates that fucoid algae (i.e., brown seaweed's that are important components of rocky, intertidal zones and estuaries) sense water motion and release eggs and sperm only when the sea is calm. Nearly 100% of their eggs are fertilized. The proposed experiments will determine how these algae sense water motion and whether similar responses are found in several other species that are harvested …