Living along an estuarine gradient : juvenile performance, reproductive patterns, and heat-shock protein expession [sic] in the barnacle Balanus glandula
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Date
2004
Authors
Berger, Michael Stuart, 1967-
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Abstract
The intertidal barnacle Balanus glandula is predominantly an open coast species in the Northeast Pacific. However, B. glandula commonly inhabits estuaries where environmental conditions such as salinity and temperature drastically differ from the open coast. The increased variability of environmental conditions within an estuary, and subsequent stress, can affect the survivorship and growth of recently settled juveniles and, in addition, adult reproductive dynamics. Along an environmental gradient, at the oceanic, mid-estuarine, and riverine end of the South Slough Estuary, Oregon, USA, I examined (1) seasonal variation in the reproductive cycle of adult B. glandula and (2) survivorship and growth rates of recently metamorphosed laboratory reared juvenile B. glandula outplanted to the field. High densities of adult B. glandula were observed at all sites. The oceanic site was characterized by a reproductive output that was higher than the mid-estuarine site. However, higher survivorship and growth rates were observed at the mid-estuarine site than the oceanic site. Although a disparity was observed between the oceanic and mid-estuarine sites, both sites ranked closer to each other than to the riverine site. A low annual reproductive output coupled with high juvenile mortality and a low growth rate made the riverine site the least suitable habitat within the estuary. In the intertidal, where organisms reside in an interface between an aquatic and terrestrial habitat, body temperatures of sessile marine organisms can reach 20–35°C for extended periods of time during low tide. In response to an environmental stress, such as temperature, organisms will upregulate heat-shock protein synthesis in an effort to save existing protein pools from irreversible damage. I examined the physiological response of the intertidal barnacle, Balanus glandula, to thermal stress by measuring thermally induced heat-shock protein expression. Induction of hsp70 occurred as low as 23°C regardless of field acclimatization or laboratory acclimation. Induced levels of hsp90 reached a maximum at 23–28°C; levels decreased by 33°C. Although a heat-shock response was observed, evidence of irreversible protein damage was not observed. The heat-shock response of B. glandula appears to be different than other intertidal organisms (e.g., molluscs). This dissertation includes my co-authored material.
Description
xii, 142 p. OIMB PhD Dissertation
A print copy of this title is available through the UO Libraries under the call number: SCIENCE QL444 .C58 B47 2004
A print copy of this title is available through the UO Libraries under the call number: SCIENCE QL444 .C58 B47 2004
Keywords
Barnacles, Balanus glandula, Barnacles -- Oregon -- South Slough (Coos County), Balanus -- Oregon -- South Slough (Coos County), Ecophysiology -- Oregon -- South Slough (Coos County), Barnacles -- Reproduction