Kaneohe Bay Research
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For information about HIMB please contact: The Hawai‘i Institute of Marine Biology P.O. Box 1346 Kane‘ohe, Hawai‘i 96744 tel: (808) 236-7401 fax: (808) 236-7443 http://hawaii.edu/HIMB/
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ItemRegeneration functions and microbial ecology of coral reefs(University of North Carolina, Chapel Hill, 1905-05)Rapid rates of production and consumption on coral reefs have been indirectly measured by several investigators who suggested the existence of rapid regeneration rates in these ecosystems. During 15 months in 1967-68 I attempted to characterize mechanisms and rates of regenerative functioning in coral reefs at Kaneohe Bay, Oahu, Hawaii and Eniwetok Atoll. Marshall Islands. Emphasis was placed on the study of bacteria and other microorganisms based on their typically important regenerative roles in other ecosystems. Complex internal spaces in reef formations and non-living porous coral skeletons appeared to be major sites of regenerative processing. Dead coral heads were obtained from several reef stations and returned to the laboratory for study of internally contained regenerative sediments. Sediments were characterized by chemical and biological assays, and results were compared between local stations as well as between the two major study regions. Additional measurements were made on selected fragments of reef regenerative mass (dead coral). Eniwetok Atoll regenerative sediments contained less than 1% acid-soluble residues, while similarly collected sediments from Kaneohe Bay contained about 24% insoluble (terrigenous) residues. Station averages for total sediment organic matter by ashing ranged from 6 to 12%, and Kjeldhal nitrogen values ranged from 0.2 to 0.7%. Significant amounts of soluble phosphorus and amino nitrogen were released from the dead head spaces during sediment recovery. Regenerative sediments and adjacent skeletal substrates were heavily populated by bacteria, diatoms, protozoa and meiofauna. Bacterial plate counts gave average values of 10 8 - 10 9 colonies per gram sediment. Significant numbers of bacteria were chitin or agar digesting types. Visual counts of diatoms gave values as high as 10 6 cells per gram dry sediment, and were directly proportional to chlorophyll "a" content of the sediments. Bottle respirometry showed consumption of 0.06 to 0.50 mg 02 per g dry sediment per hour. Characteristic mean values obtained for each station appeared to be directly related to the wave and current energy at each station. Antibiotics significantly reduced sediment respiration. Respirometry of algal-encrusted dead coral fragments showed rapid rates of production (P) and consumption (R). Antibiotic treatment of these fragments interfered with their Rand P in a coupled manner. Respirometry of entire dead heads showed that sediment respiration accounted for about 10% of the total respiration in each head. Bacteria were actively removed from water circulated over living and dead coral heads in a laboratory reef simulation. Some infaunal animals apparently digested bacteria that were removed from the water. Observations on infauna of the regenerative system indicated an active role in sediment production and processing, and in maintenance of internal spaces. The infauna apparently acted in symbiosis with the microorganisms to promote rapid organic breakdown processes. Total organic matter, Kjeldahl nitrogen, terrigenous derivatives, and pheophytin showed highest mean levels in sediments from Kaneohe Bay nearshore heads, whereas bacterial counts, diatom counts, and sediment metabolism were highest in sediments from offshore heads. These comparative differences were indications of stressed regenerative function in nearshore reefs, possibly due to land-derived inputs. Parameters measured for outer Kaneohe Bay were strikingly similar to various measurements at Eniwetok, suggesting that regenerative function was similar in geographically separated reefs. Some simplified energy diagrams for simulation suggest how animals and microorganisms are coupled to perform effective mineral recycling and structural renewal of reefs.
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ItemReverse Weathering Reactions within Recent Nearshore Marine Sediments, Kaneohe Bay, Oahu( 1978-02)The purpose of this study is to present the results of mineralogical and petrochemical analyses of the solid phase components and the inorganic chemistry of the interstitial waters of the Recent anoxic sediments of Kaneohe Bay, Oahu. Nineteen shallow 1-4 meter gravity cores of the lagoonal sediments of Kaneohe Bay were analyzed for pore water chemistry and seven were subjected to detailed mineralogical and petrochemical analyses. The pore waters of the sediment column show depletions in dissolved SO =4, Ca++, Mg++ and Sr++ accompanied by increases in titration alkalinity, NH4 + , PO 4 -3 and Si02 with respect to the overlying seawater with increasing subbottom depth. Na+, Cl-, K+ and Fetot exhibit minor departures from overlying bay waters assuming that depletions of Na+ and Cl- are the result of an influx of meteoric ground water from beneath the bay's floor. The bay may be divided into two parts on the basis of the rates of pore water diagenesis: in the southern part of the bay, S0 =4 is completely depleted within 80cm subbottom depth, whereas in the northern part, complete S0 =4 reduction does not occur at depths to 350cm. The southern sediments are contaminated by raw, high C/N sewage, resulting in an increased metabolic reduction rate of S0 =4 by anerobic bacteria over that observed in the unpolluted northern bay. Calculation of S0 =4 consumed versus alkalinity plus NH=4 produced indicates a relationship in which roughly one-half of the "produced alkalinity" has been consumed in the formation of authigenic minerals, primarily nontronite and aragonite. Quantitative mineralogical and petrochemical analyses of the solid phase components reveal the loss of amorphous iron-oxyhydroxides, biogenic opaline silica, and amorphous aluminosilicate with increasing subbottom depth. Pyrite formation occurs immediately below the sedimentwater interface. Scanning Electron Microscope observations show a hierarchy of morphologies with depth: single l-micron crystals to 30- micron diameter framboids. Pyrite formation accounts for the lack of detectable S= within the pore waters and is dependent on the availability of pore water iron derived from the dissolution of amorphous iron-oxyhydroxides. The amount of pyrite present below 40cm subbottom depth exceeds the amount which could be formed by the complete reduction of buried pore water S0=4 suggesting the importance of bioturbation in the mixing of pore and overlying seawaters. Authigenic nontronite and mixed-layer smectite-illite are being formed as the result of the reaction of amorphous aluminosilicate with pore water Si02 from opal dissolution and pore water Fe and/or other cations. In those cores where sufficent dissolved iron exists in the pore water, nontronite forms, whereas when dissolved iron is not present as evidenced by the presence of dissolved S= in the pore water, a mixed-layer smectite-illite is formed. The amount of smectite formed is limited by the amount of opal which dissolves. For Kaneohe Bay sediments an average of 0.12 weight percent authigenic smectite is added annually to the sediment column. Minor amounts of authigenic plagioclase, phillipsite, clinoptilolite, analcime, sepiolite, siderite and apatite are also being formed within the sediments. The relationship between reduced pore water Fe and smectite formation suggests that reverse weathering reactions resulting in either authigenic nontronite or mixed-layer smectite-illite may occur in all anoxic marine sediments rich in terrigeneously-derived, poorly-crystalline "kaolinite" and containing enriched pore water Si02. Assuming that 10 percent of the total flux of the world river sediments delivered to the ocean is deposited in Kaneohe Bay-type environments and that rates of reaction are similar to those observed in Kaneohe Bay, then approximately 6 percent of the CO2 consumed by rock weathering may be returned annually to the atmosphere by these reactions.
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ItemRemoval and repopulation of the fishes on an isolated patch coral reef in Kaneohe Bay, Oahu, Hawaii(University of Hawaii, Honolulu, 1967-06-01)
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ItemThe relation of temperature to calcification in Montepora verrucosa(Loma Linda University, 1971-08)Reef-building or hermatypic corals are limited in their geographical distribution to the warmer waters of tropical oceans. Significant coral growth occurs only in water ranging from 180 C to 330 C, and massive reefs form only at temperatures toward the upper end of this temperature range (Wells, 1957). The coral skeleton is composed almost entirely of calcium carbonate (CaC03) with the crystalline structure of aragonite; calcite is completely absent. H. Lowenstam (1954) has suggested that the failure of corals to produce any calcite may be the factor influencing the smaller number of scleractinian species in cooler water. Organisms that can produce both aragonite and calcite tend to produce calcite during colder seasons and aragonite during warmer seasons. Thus, by their nature of calcification, corals may physiologically limit their geographical distribution. Physiological study of corals began in the early nineteenth century. Towards the latter part of the century, some work with growth rates of reef corals was started by Alexander Agassiz (1890). Similar studies have since been made by others (Abe, 1940; Boschma, 1936; Edmondson, 1929; Kawaguti, 1941; Ma, 1937; Mayor, 1924; Motoda, 1940; Stephenson and Stephenson, 1933; Tamura and Hada, 1932; and Vaughan, 1919). All of these stud ies involved the technique of allowing the coral to grow for long periods, days to years, in its natural environment, with size and weight measurements being taken at periodic intervals. However, more recent attempts to estimate growth rates have involved chemical methods of measuring the incorporation of calcium into the skeleton under controlled laboratory conditions (Kawaguti and Sakumoto, 1948; Coreau, 1959; and Goreau and Goreau, 1959, 1960a, 1960b). The present study employed a procedure involving the incorporation of radioactive calcium-45 into the coral skeleton to determine the optimum temperature for calcium deposition in Montipora verrucosa, a common Indo-Pacific hermatypic sc leractinian. In contrast to previous studies, short periods of one-half to six hours were used. These shorter periods were used in order to reduce adverse environmental laboratory conditions.
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ItemThe Effects of ultraviolet radiation on skeletal growth and bleaching in four species of Hawaiian corals(California State University, Long Beach, 1991-05)Coral bleaching has been attributed to many factors, including increased exposure to ultraviolet radiation (UV). The effects of partial and full spectrum UV on coral skeletal growth and bleaching were investigated. Responses were species-specific and depthdependent. Montipora verrucosa, Pocillopora damicornis, and P. danai collected from 1 m maintained or increased their calcification rates when exposed to partial UV or shielded from UV. M. verrucosa collected from 1.5 mexhibited bleaching via zooxanthella loss regardless of the UV treatment, probably because of reduced salinity and water temperature. M. verrucosa collected from 8.5 m bleached only when exposed to increased intensities of PAR, while Porites compressa collected from 8.5 m bleached only when exposed to increases in both PAR and UV. All bleaching resulted from loss of zooxanthellae rather than loss of pigment from zooxanthellae. Lower surface augmentation of color via zooxanthella increases often occurred with a corresponding decrease in upper surface zooxanthella density.