Pacific Science, Volume 45, Numbers 1-4, 1991

45: Index - Pacific Science

Tue, 01 Jan 1991 00:00:00 GMT

45:4 Table of Contents - Pacific Science

Tue, 01 Oct 1991 00:00:00 GMT

A Temporal Sequence (Chronosequence) of Soil Carbon and Nitrogen Development after Phosphate Mining on Nauru Island

Manner, Harley; Morrison, RJ — Tue, 01 Oct 1991 00:00:00 GMT

Ten composite soil samples (0-15 cm depth) were collected from abandoned phosphate-mined sites on Nauru Island (Central Pacific) and analyzed for % organic C and % N. The samples represent a temporal sequence (chronosequence) of soil development spanning < 55 yr. The increase of% C and % N was fairly rapid. In recently mined sites « 1 yr) the values of % C were between 0.41 and 0.48, and those for % N were between 0.03 and 0.04. Fifty-five years after mining, the values of % C and % N were 4.56 and 0.33, respectively, and comparable to the amounts found in undisturbed Lithic Haplustolls, Typic Haplustolls, and Lithic Ustorthents epipedons. These changes in soil properties are considered to be a function of time and the accompanying seral development of vegetation (particularly the fern cover of Nephrolepis biserrata and Polypodium scolopendria) , because parent materials, climate, and other factors of soil formation are considered to be constant. Rate of soil development is faster in the unconsolidated sands and limestone rubble of the pit bottoms and slower on the dolomitic limestone pinnacle surfaces.

Natural Interspecific Hybridization in Gunnera (Gunneraceae) of the Juan Fernandez Islands, Chile

Pacheco, Patricia; Stuessy, Tod F; Crawford, Daniel J — Tue, 01 Oct 1991 00:00:00 GMT

Natural interspecific hybridization between Gunnera bracteata and G. peltata (Gunneraceae) in the Juan Fernandez Islands, Chile, is analyzed morphologically and chemically. Parental types from isolated populations were compared with parents and intermediates occurring together in Quebrada Villagra on Masatierra. Two transects were made in that area, one in a relatively undisturbed site, and another along a disturbed path. Hybrid indexes and distance diagrams were used to analyze morphological relationships, and leafflavonoids revealed chemical affinities. Minor flavonoid divergence between parental species precluded detailed analysis of dynamics of hybridization. Morphological analysis revealed intermediacy in both transects,with intergradation back toward both parents. It is suggested that introgressive hybridization is occurring in Quebrada Villagra between these two wind-pollinated species, with more hybridization taking place in disturbed regions. Reduction in surface area and changes in the ecology of Masatierra during the past four million years may have brought the two species into closer contact and aided hybridization.

Cyclohelia lamellata, New Genus and Species of Stylasteridae (Cnidaria: Hydrozoa) from the Bering Sea

Cairns, Stephen D — Tue, 01 Oct 1991 00:00:00 GMT

A new genus and species of Stylasteridae is described, Cyclohelia lamellata, based on one specimen from 550 m off the Pribilof Islands, Bering Sea. The species is unusual in having a lamellate growth form and unique in having elliptical dactylopore spines that are rimmed on all sides. The genus is hypothesized to be most closely related to Distichopora and Sporadopora. Cyclochelia lamellata is one of the most northerly records of a stylasterid in the Pacific Ocean.

Review of the Tabanidae (Diptera) of Eastern Melanesia and Samoa (Excluding New Caledonia), with Description of Three New Species.

Burger, John F — Tue, 01 Oct 1991 00:00:00 GMT

Three species of Tabanidae, one Cydistomyia from the Solomon Islands and two species of Tabanus from Fiji, are described. New distribution records for two Cydistomyia, one Japenoides, and three Tabanus species are presented for the Solomon Islands. Cydistomyia solomensis is reported from the Santa Cruz Islands for the first time. A list of Tabanidae from eastern Melanesia and Samoa (excluding New Caledonia) is given, as well as a key to genera and species.

Biology of the Shortfinned Eel Anguilla obscura in Lake Te Rotonui, Mitiaro, Cook Islands

Jellyman, DJ — Tue, 01 Oct 1991 00:00:00 GMT

Lake Te Rotonui, a shallow depression lake in the center of Mitiaro Island, southern Cook Islands, contains freshwater eels despite having no surface connection to the sea. During a survey of the eel population in July 1988, all of the 287 eels captured using fyke nets and gaffs were Anguilla obscura, although it is possible that A. megastoma and perhaps A. marmorata also occur in small numbers. Ages of eels were found from burnt otoliths; it was assumed that otolith zones were formed annually, although this could not be validated. Growth rates were slower than those of other tropical eel species, being similar to those of temperate species. Eels fed exclusively on Oreochromis mossambica, which was abundant in the lake. The relatively slow growth in the presence of abundant food may be due to high and stressful summer water temperatures. From length and age frequency distributions, it is suggested that recruitment of glass-eels into the lake is intermittent and via submarine outfalls. A review of the limited larval information suggested that A. obscura spawns to the east of Tahiti, with larvae transported west and south by the South Equatorial Current.

The Sulawesi Black Racer, Coluber (Ptyas) dipsas, and a Remarkable Ectoparasitic Aggregation

Lazell, James D; Keirans, James E; Samuelson, G Allan — Tue, 01 Oct 1991 00:00:00 GMT

Twelve specimens of the Sulawesi black racer, Coluber (Ptyas) dipsas, have been reported in the literature; none of these is from American collections. Morphology and relationships of the snake, based on a fresh specimen, are discussed. Thirteen ticks of two species, Amblyomma cordiferum and A. helvolum (Ixodidae), and the beetle Aplosonyx nigripennis (Chrysomelidae) were recovered from an old wound site on a 1465-mm female Coluber dipsas from Minahasa, Sulawesi Utara, Indonesia. Both tick species are new island and new host records. There have been no specific plant hosts reported to date for this beetle, of a phytophagous family.

A New Tern (Sterna) Breeding Record for Hawaii

Conant, Sheila; Clapp, Roger; Hiruki, Lisa; Choy, Barry — Tue, 01 Oct 1991 00:00:00 GMT

Recent observations of terns, either the Old World Little Tern (Sterna albifrons) or the New World Least Tern (Sterna antillarum), at Pearl and Hermes Reef in the Northwestern Hawaiian Islands have documented that one of these species bred there in 1988 and possibly also in the several preceding years. Two small Sterna terns were first observed at Pearl and Hermes in 1984, and the numbers subsequently observed there gradually increased until five birds were recorded in 1988. In 1988 a nest containing three eggs was found, and at least one egg produced a nestling. No small Sterna terns were seen during a 2-week visit to the atoll in 1989 or a 2-day visit in 1990. No specimens were collected, and photographs taken do not permit specific identification of the birds. We favor S. albifrons sinensis because there are now specimen records of Asiatic Little Terns from French Frigate Shoals and Midway Atoll and a sight record from Laysan Island, and because a review of prevailing wind systems in the Pacific and other vagrant bird records from the Northwestern Hawaiian Islands suggest that such birds are more likely to arrive from the west than from the east.

Extinct and Extirpated Birds from Aitutaki and Atiu, Southern Cook Islands

Steadman, David W — Tue, 01 Oct 1991 00:00:00 GMT

Six archaeological sites up to 1000 years old on Aitutaki, Cook Islands, have yielded bones of 15 species of birds, five of which no longer occur on the island: Pterodroma rostrata (Tahiti Petrel); Sula sula (Red-footed Booby); Dendrocygna, undescribed sp. (a large, extinct whistling duck); Porzana tabuensis (Sooty Crake); and Vini kuhlii (Rimatara Lorikeet). Of these, only S. sula and P. tabuensis survive anywhere in the Cook Islands today. The nearest record of any speciesofDendrocygna is in Fiji. Aside from the aquatic species Egretta sacra (Pacific Reef-Heron) and Anas superciliosa (Gray Duck), the only native, resident land bird on Aitutaki today is the Society Islands Lorikeet (Vini peruviana), which may have been introduced from Tahiti. Residents of Aitutaki note that Ducula pacifica (Pacific Pigeon) and Ptilinopus rarotongensis (Cook Islands Fruit-Dove) also occurred there until the 1940sor 1950s.There is no indigenous forest on Aitutaki today. The bones from Aitutaki also include the island's first record of the fruit bat Pteropus tonganus . Limestone caves on the island of Atiu yielded the undated bones of six species of birds, three of which no longer exist there or anywhere else in the Cook Islands: Gallicolumba erythroptera (Society Islands Ground-Dove), Ducula aurorae (Society Islands Pigeon), and Vini kuhlii. Each of these species has been recovered from prehistoric sites on Mangaia as well. The limestone terrain of Atiu is mostly covered with native forest that supports populations of Ducula pacifica, Ptilinopus rarotongensis, Collocalia sawtelli (Atiu Swiftlet), and Halcyon tuta (Chattering Kingfisher). The survival of these land birds depends upon protection of Atiu's forests.

45:3 Table of Contents - Pacific Science

Mon, 01 Jul 1991 00:00:00 GMT

Fate of Carbaryl, l-Naphthol, and Atrazine in Seawater

Armbrust, Kevin L; Crosby, Donald G — Mon, 01 Jul 1991 00:00:00 GMT

The fate of carbaryl, l-naphthol, and atrazine was determined under light and dark conditions in filter-sterilized and raw (unfiltered) seawater. Carbaryl was hydrolyzed in the dark, quantitatively, to l-naphthol with a half-life of 24 hr at pH 7.9 or 23 hr at pH 8.2 (24°C). Naphthol was stable in the dark in sterile seawater, but was degraded to undetectable levels in 96 hr in raw seawater. In artificial sunlight, carbaryl degraded with a half-life of 5 hr and l-naphthol was completely degraded after 2 hr. No further degradation products were observed for either compound. Atrazine was stable under light and dark conditions in sterile seawater; however, in raw seawater, it was degraded by 23% after 96 hr. These data suggest that atrazine may be stable enough in seawater to permit exposure of susceptible marine life, while, in the presence of sunlight, carbaryl and l-naphthol would rapidly dissipate to undetectable levels.

Fate of Model Xenobiotics in Calcareous Marine Algae

Inouye, Laura S; Crosby, Donald G — Mon, 01 Jul 1991 00:00:00 GMT

Uptake, depuration, and metabolism of p-nitroanisole (PNA) and p-nitrophenol (PNP) were investigated in Halimeda, Padina, and Porolithon species, all of which are calcareous marine algae found in tropical waters . The algae were exposed to filtered seawater solutions of either PNA or PNP in a static system for 24 hr (uptake period), then placed in clean water and allowed to release absorbed chemical and possible metabolites for 24 hr (depuration period). Concentrations of the chemicals were monitored spectrophotometrically, and the water at the end of uptake and depuration was extracted onto a column of Amberlite XAD-4 resin, eluted sequentially with methylene chloride and methanol, and analyzed for metabolites by high-pressure liquid chromatography (HPLC). Results showed that the algae absorb PNA but not PNP. There was no indication that they were capable of metabolizing PNA, except inconsistently, to PNP. However, half of the absorbed PNA remained unaccounted for, and may either have been metabolized to undetected metabolites or bound to tissue macromolecules.

Effects of Nutrient Enrichment and Water Motion on the Coral Pocillopora damicornis

Stambler, Noga; Popper, Nurit; Dubinsky, Zvy; Stimson, John — Mon, 01 Jul 1991 00:00:00 GMT

Exposure of the hermatypic coral Pocillopora damicornis (Linnaeus) to elevated levels of dissolved inorganic phosphorus did not affect the colony or the zooxanthellae. Exposure to elevated levels of dissolved inorganic nitrogen and inorganic nitrogen + phosphorus led to an increase in algal density, and as a result, to an increase in the chlorophyll concentration. These latter two experimental enrichments slowed skeletal growth rate of the corals, probably because of a decrease in the photosynthetic rate of the algae and perhaps a decrease in the translocation of photosynthetic products from the algae to the coral. The algae probably used the photosynthetic energy for their own increased growth. Experimental manipulation of water motion used in these experiments did not affect the coral or the symbiotic algae.

Effects of Two Petroleum Products on Pocillopora damicornis Planulae

Tan Te, Franklyn — Mon, 01 Jul 1991 00:00:00 GMT

Pocillopora damicornis planulae were exposed to different concentrations of benzene and gasoline:oil mixtures to determine the lethal concentrations and biological responses of the coral larvae. Bioassay tests with either open or closed static solutions of the test compounds were monitored. Planulae settlement was considered as the visible reaction to the hydrocarbon compound introduced. This study found that corallite formation was significantly influenced by the different concentrations of the test compound, but no clear correlation between concentration of the test compound and rate of corallite formation was ascertained. Mortality was minimal in most of the test concentrations utilized in the experiments.

Preliminary Observations on Effects of Pesticides Carbaryl, Naphthol, and Chlorpyrifos on Planulae of the Hermatypic Coral Pocillopora damicornis

Acevedo, Roberto — Mon, 01 Jul 1991 00:00:00 GMT

Planulae larvae of the reef coral Pocillopora damicornis were exposed to three pesticides in concentrations ranging from 0.01 to 100 ppm. Actively swimming planulae were held in test solutions for 96 hr, after which viability was determined. Carbaryl and l-naphthol in concentrations up to 10 ppm had no effect on the planulae after 96 hr. Chlorpyrifos at levels of 1 ppm and higher resulted in mortality in 50 to 100% of the trials.

Mortality and Settlement Success of Pocillopora damicornis Planula Larvae during Recovery from Low Levels of Nickel

Goh, Beverly PL — Mon, 01 Jul 1991 00:00:00 GMT

Effects on mortality and settlement of Pocillopora damicornis planula larvae during recovery from low levels of Ni++ were investigated. Results indicated that a nickel concentration of 9 ppm over 12 hr was sufficient to cause 50% mortality in larvae 39.6 hr after removal of the toxicant. Settlement in larvae was more sensitive, showing significantly reduced settlement rates from 9 days into recovery, after exposure to I ppm Ni++ at durations of 12-96 hr. It is recommended that coral planula larvae be utilized more extensively in pollution studies.

Kinetics of Dark Oxygen Uptake of Pocillopora damicornis

Newton, PA; Atkinson, MJ — Mon, 01 Jul 1991 00:00:00 GMT

Colonies of Pocillopora damicornis were placed in a sealed aquarium in the dark. Water velocity was altered and measured in 10 different experiments. During each experiment, seawater in the aquarium was supersaturated with oxygen (02 ) and then O2 concentration was measured through time until the concentration in the aquarium decreased to 0.3 mg O2 1-1 . Resulting O2 uptake curves were interpreted as a function of water velocity. Rate of O2 uptake fit a hyperbolic equation (d02 /dt = Vm02 /Ks + O2 ) . Maximum uptake rate (Vm ) varied between 0.12 and 0.27 mg O2 1- 1 min " (mean = 0. 18), and the half-saturation constant (Ks ) varied between 0.86 and 2.52 mg O2 1-1. Both Vm and K, did not vary with water velocity, indicating that in these experiments, water motion had little influence on either diffusive boundary layers near the coral tissue or the metabolic rate of O2 uptake. Even supersaturated concentrations of O2 did not completely saturate the uptake capacity of this enzyme system.

Behavioral and Ecological Relationships of a Parasite and Its Hosts within a Coral Reef System

Aeby, Greta S — Mon, 01 Jul 1991 00:00:00 GMT

The life cycle of the digenetic trematode Plagioporus sp. includes an intermediate stage that encysts in the scleractinian coral Porites compressa and an adult stage that probably resides in a coral-feeding fish. Coral polyps infected with metacercariae of Plagioporus appear as swollen nodules ranging in color from bright pink to white and have lost their ability to retract into their calices. The polyps' altered appearance and behavior was thought to increase their vulnerability to predation. This study investigated the effect of parasite encystment on coral growth and the effect offish predation on both coral growth and on the parasites' rate of transmission. Parasitized P. compressa showed a 50% reduction in growth when compared to nonparasitized P. compressa. No significant differences were found in growth of corals kept in predator exclusion cages and that of corals left exposed to fish predation in either group, parasitized or nonparasitized. Uncaged parasitized P. compressa showed a marked reduction in number of parasitic cysts, with the infected polyps being replaced by healthy ones. The regeneration of healthy polyps suggests that parasite removal is beneficial to the coral, and the reduction in cyst number suggests that the parasites' rate of transmission was enhanced by exposure of infected corals to fish predation.

Reproduction Effort in the Nudibranch Phestilla sibogae: Calorimetric Analysis of Food and Eggs

Haramaty, Liti — Mon, 01 Jul 1991 00:00:00 GMT

Phestilla sibogae, a nudibranch living on corals of the genus Porites, is rarely found on the reef at Kaneohe Bay, Hawaii, although Porites compressa is a dominant coral there. This is probably due to massive predation on juveniles and adults. Such predation pressure would force this species to put high effort into reproduction. In this work I found that P. sibogae laid eggs amounting to up to 17% of their body weight each day. Furthermore, based on a 100% conversion efficiency for ingested coral tissue, 51-78% of the calories each individual ate daily were channeled into egg production. Photosynthetic activity of zooxanthellae in the nudibranch's tissue suggests that the algae may provide some of the energy required by the animal's metabolism.