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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Molecular variation between populations of annual halophytes

Noble, Stuart M. January 1990 (has links)
No description available.
2

Population studies of Spartina anglica C.E. Hubbard in the Dee Estuary

Hill, Margaret Irene January 1986 (has links)
No description available.
3

A phytosociological study of the transition between salt marsh and terrestrial vegetation of Bahia de San Quintin

Neuenschwander, Leon F. January 1972 (has links)
Thesis (M.A.)--California State College at Los Angeles, 1972. / Includes bibliographical references (leaves 31-33).
4

Inter- and intraspecific variation in carbon and nutrient pools of salt marsh plants

Elsey-Quirk, Tracy. January 2010 (has links)
Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisors: John L. Gallagher, and Denise M. Seliskar, School of Marine Science & Policy.. Includes bibliographical references.
5

Spartina densiflora, an invasive species in the marshes of Humboldt Bay /

Falenski, Heinz Dieter. January 1900 (has links)
Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 116-119). Also available via Humboldt Digital Scholar.
6

The effects of salinity and inundation on salt marsh plants in the context of climate change

Tabot, Pascal Tabi January 2012 (has links)
Ecophysiology studies are needed to predict plant responses in relation to climate change. Variations in salinity and inundation are expected to influence the survival and distribution of salt marsh. The following species were chosen to study as they occur in most South African salt marshes and are representative of different tidal ranges; namely Triglochin buchenaui (lower intertidal), Bassia diffusa (upper intertidal succulent) and Limonium linifolium (upper intertidal non-succulent). To simulate climate change conditions as predicted for South Africa, a 3 x 5 controlled experiment of three inundation levels (tidal, submerged and drought) and five salinity levels (0, 8, 18, 35, 45 ppt) was conducted for each species. This resulted in 15 treatments per species. Plant responses were measured over a three month period. Triglochin buchenaui showed significant variation in height (7.57 ± 0.5 to 29 ± 1.55 cm, p < 0.005, DF = 55) with optimum growth at 0 ppt under tidal conditions; leaf area increments and relative growth rates which decreased with increasing salinity under all inundation states. There was almost a cessation of growth under submergence which reduces the plant’s regeneration potential under these conditions. Proline accumulation (1.84 ± 0.23 to 3.36 ± 0.38 mg l-1), response of photosynthetic pigments and electrolyte leakage (8.17 ± 0.80 to 38.36 ± 7.42 percent) were fundamental to osmotic and membrane response regulation. Plants survived in all inundation states at salinity up to 45 ppt, but the optimum range was 0 to 18 ppt, and best water state was the tidal condition. Viable rhizomes were produced under drought conditions. Bassia diffusa (Thunb.) Kuntze plants under submergence died within one month, irrespective of the salinity. Optimum growth occurred in plants of the tidal treatment at 18 ppt, and reduced with increased salinity and drought conditions. Plants in the tidal treatments were more succulent than the drought-treated plants. There was reduced leaf mass and high anthocyanin concentrations in drought-treated plants and these effects increased with salinity. Soil and leaf water potential were positively correlated with anthocyanin concentration in leaves and stems, suggesting anthocyanin accumulated in response to drought and could be an adaptation to lower the plant’s water potential under drought conditions. A shift of anthocyanin from leaves to stems was found in drought-treated plants, and this possibly enables the maximization of photosynthesis in leaves, to complement its role in osmotic balance and photo-protection. Growth of Limonium linifolium showed that the plant was tolerant to a wide range of salinity under both tidal and drought conditions, but was susceptible to complete submergence, with high membrane damage even in tidal-treated plants. Plants died within 2 weeks of complete submergence. Results further indicated that L. linifolium tolerates extreme drought by accumulating large quantities of proline and oxalic acid, which consequently lowers its water potential for uptake of soil water of high salinity. Excess salts were excreted through salt glands. This is an important adaptation for a plant that thrives in a highly variable saline habitat Further investigation of submergence effects on upper intertidal species using B. diffusa showed three key stages in the response. A drop in chlorophyll a+b within 6 hours (4.2 ± 0.2 to 2.4 ± 0.3 mg l-1) with a corresponding increase in carotenoid concentration (0.6 ± 0.1 mg l-1) indicated an immediate response to submergence. Oxalic acid concentration was highest on Day 4 (13.6 mM) as opposed to control levels, indicative of its role in submergence tolerance, thus Day 4 may be the peak of positive acclimation. The third phase was marked by a sharp increase in electrolyte leakage to 47.5 ± 2.6 percent on Day 10, from 9.4 ± 1.4 percent on Day 7, with a corresponding decrease in total dissolved solutes between Days 7 and 10. Results suggest that oxalic acid accumulates under submergence possibly as a stabilizing osmolyte. The threshold for tolerance of the species under submergence is 7 days with membrane damage thereafter. Bassia diffusa would not survive prolonged submergence (> 7 days) but could survive submergence of short duration (< 7 days) through continuous underwater photosynthesis, accumulation of osmolytes such as oxalic acid and carotenoid, and maintenance of relative water content and succulence within control levels. When considered together, results showed that the two upper intertidal species were sensitive to waterlogging and would not survive complete submergence, whereas the lower intertidal species could in addition to its natural range, thrive in conditions typical of the upper intertidal range, namely prolonged dry conditions and high sediment salinity. These results have important implications for the future management of salt marshes under predicted climate change conditions. In permanently open South African estuaries, a landward migration of salt marsh will be possible if coastal squeeze is limited and the rate of landward recruitment is on par with sea level rise. In this case salt marsh species would retain their current zonation while shifting inland. Increased sea storms and saltwater intrusion could lead to high salinity concentration in the sediment and significantly reduce growth of salt-sensitive plants. In estuaries that are temporarily open to the sea, reduced freshwater inflow will result in an increase in mouth closure, high water levels, prolonged submergence, and consequently die back of salt marsh vegetation. On the other hand increased abstraction and drought would result in low water levels and high sediment salinity which would decrease growth and survival of salt marsh. This research has provided new knowledge on the ecophysiology of salt marsh plants which can be used to predict the responses of plants to climate change.
7

Environmental change in San Francisco Estuary tidal marshes

Watson, Elizabeth Burke. January 2006 (has links)
Thesis (Ph. D.)--University of California, Berkeley, 2006. / Includes bibliographical references.
8

Modern pollen and vegetation relationships in Bay of Fundy salt marshes

Beecher, Carolyn Beth. January 2001 (has links)
This study examines modern relationships among salt marsh plant species and their pollen in three salt marshes located on the northwest coast of the Bay of Fundy, New Brunswick. Linear regression analysis of pollen in 35 surface sediment samples and vegetation cover on small (<15 m) and broad (>15 m) scales show that, with the exception of Poaceae and Cheno Am, pollen corresponds well with fine-scale patterns of salt marsh vegetation. Scatter diagrams of paired pollen and cover data illustrate that cover of Triglochin is over-represented by its pollen, Glaux is under-represented, and Poaceae, Cheno Am, and Plantago are inconsistent. Tidal mixing and differential inputs from local, regional, and extra-regional sources with elevation limit the establishment of plant-pollen relationships for Cheno Am and Poaceae but not for other taxa. Comparison of 35 modern analogs from five vegetation zones using squared chord distance show that zones are distinct such that the marsh-terrestrial interface can be tracked with the greatest degree of certainty in a salt marsh paleo-ecological record and other marsh zones can be tracked when a conservative threshold of dissimilarity is used.
9

Ecological status and dynamics of a salt marsh restoration in the Salmon River Estuary, Oregon /

Morlan, Janet C. January 1991 (has links)
Thesis (M.S.)--Oregon State University, 1992. / Typescript (photocopy). Includes bibliographical references (leaves 105-112). Also available via the World Wide Web.
10

Modern pollen and vegetation relationships in Bay of Fundy salt marshes

Beecher, Carolyn Beth. January 2001 (has links)
No description available.

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