Some Observations on the Chlorophyll Maximum and Primary Production in the Eastern North Pacific

An oceanographic transect between Central California and the Hawaiian Islands delimited a continuous subsurface chlorophyll maximum associated with an oxygen maximum at 1% to 0.1% light penetration depths. The phytoplankton community consisted primarily of nannoplankton with a prominent diatom component, and was photosynthetically active as measured in „low light level”︁ incubators, contributing an estimated 20–30% to total water column production. Functioning as a nutrient trap blocking the vertical movement of nutrients into the upper euphotic zone, the chlorophyll maximum apparently required an overlying pycnocline for development.     

Relationship between Chlorophyll Concentration and Photosynthestic Potential in Callus Cells

Chlorophyll synthesis in the regreening photoheterotrophic calluscultures of Arachis hypogaea and Kalanchoe fedtschenkoi wassaturated at a light intensity of 5,000 lux. However, the optimaldevelopment of photosynthetic functions (O₂ evolution, CO₂ fixation,photosystem activities) required more irradiance (12,000–14,000lux). It was concluded that chlorophyll is not a useful indexof the photosynthetic potential in such cells. (Received January 23, 1981; Accepted July 10, 1981)     

A Sea of Change: Biogeochemical Variability in the North Pacific Subtropical Gyre

The North Pacific Subtropical Gyre (NPSG) is the largest ecosystem on our planet. However, this expansive habitat is also remote, poorly sampled, and therefore not well understood. For example, the most abundant oxygenic phototroph in the NPSG, Prochlorococcus, was described only a decade ago. Other novel Bacteria, Archaea and Eukarya, recently identified by nucleic acid sequence analysis, have not been isolated. In October 1988, an ocean time-series research program was established to study ecosystem processes in the gyre, including rates and pathways of carbon and energy flow, spatial and temporal scales of variability, and coupling of ocean physics to biogeochemical processes. After a decade of ecosystem surveillance, this sentinel observatory has produced an unprecedented data set and some new views of an old ocean. Foremost is evidence for dramatic changes in microbial community structure and in mechanisms of nutrient cycling in response to large-scale ocean–atmosphere interactions. These and other observations demand reassessment of current views of physical-biogeochemical processes in this and other open-ocean ecosystems.     

Trends in Ocean Colour and Chlorophyll Concentration from 1889 to 2000, Worldwide

Marine primary productivity is an important agent in the global cycling of carbon dioxide, a major ‘greenhouse gas’, and variations in the concentration of the ocean''s phytoplankton biomass can therefore explain trends in the global carbon budget. Since the launch of satellite-mounted sensors globe-wide monitoring of chlorophyll, a phytoplankton biomass proxy, became feasible. Just as satellites, the Forel-Ule (FU) scale record (a hardly explored database of ocean colour) has covered all seas and oceans – but already since 1889. We provide evidence that changes of ocean surface chlorophyll can be reconstructed with confidence from this record. The EcoLight radiative transfer numerical model indicates that the FU index is closely related to chlorophyll concentrations in open ocean regions. The most complete FU record is that of the North Atlantic in terms of coverage over space and in time; this dataset has been used to test the validity of colour changes that can be translated to chlorophyll. The FU and FU-derived chlorophyll data were analysed for monotonously increasing or decreasing trends with the non-parametric Mann-Kendall test, a method to establish the presence of a consistent trend. Our analysis has not revealed a globe-wide trend of increase or decrease in chlorophyll concentration during the past century; ocean regions have apparently responded differentially to changes in meteorological, hydrological and biological conditions at the surface, including potential long-term trends related to global warming. Since 1889, chlorophyll concentrations have decreased in the Indian Ocean and in the Pacific; increased in the Atlantic Ocean, the Mediterranean, the Chinese Sea, and in the seas west and north-west of Japan. This suggests that explanations of chlorophyll changes over long periods should focus on hydrographical and biological characteristics typical of single ocean regions, not on those of ‘the’ ocean.     

Correlation between Chlorophyll and Chlorogenic Acid Content in Tobacco Leaves

Developmental stages of tobacco (Nicotiana tabacum L. cv. Burley 21) flower and capsule were correlated with tissue contents of polyphenols and activities of phenylalanine ammonialyase, polyphenoloxidase, and peroxidase. Chlorogenic acid, scopolin, and scopoletin were present in most tissues, whereas rutin and two dihydroxyphenolic glycosides concentrated primarily in the corolla and placenta, respectively. Ovules contained only chlorogenic acid. As development progressed, polyphenols accounted for nearly 15% of the dry weight in the green capsule of field-grown plants. Fertilization triggered a rapid increase of chlorogenic acid in the ovary. When l-phenylalanine-U-¹⁴C was fed to the detached green capsules and capsule parts, an incorporation of radioactivity into chlorogenic acid and dihydroxyphenolic glycosides occurred which suggested in situ synthesis of these compounds. This was subtantiated by a positive correlation between phenylalanine ammonia-lyase activity and polyphenol accumulation. High polyphenoloxidase activity was associated mainly with the ovary, whereas peroxidase activity was maximal during senescence of all tissues. Polyacrylamide gel slab electrophoresis revealed five cathodic bands and one diffuse zone with poly-phenoloxidase activity in flower extracts. Two anodic poly-phenoloxidase isozymes appeared only in the fertilized ovary. Among 17 peroxidase isozymes, six cathodic forms were present throughout floral development, and the anodic ones increased in number and activity at the later stages of capsule growth.     

Correlation between Genetic Variability and Body Size in Vertebrates

An analysis of allozymic variation carried out in the main groups of vertebrate animals revealed a tendency towards the increased level of genetic polymorphism in the species of small animals compared to the large ones. This tendency was clearly followed in caudate amphibians, fishes, and mammals. The data are discussed in terms of the integration of monogenic and polygenic systems in the populations. It is hypothesized that this relationship between heterozygosity and body size confirms more general regularity consisting in highly statistically significant correlation between polygenic heterozygosity, maturation rate and life span. It is suggested that high rate of development in small animals resulting in early sexual maturation, can serve as a mechanism determining correlation between heterozygosity and body size at the species level. As a result, compared to large animals, small animals display higher rates of generation change, resulting in accelerated growth of population size and faster accumulation of genetic variability.     

Variability of Morphobiological Characteristics of the Pacific Herring Clupea pallasii from Arctic and Pacific Populations

Journal of Ichthyology - A comparative analysis of the biological and morphometric characteristics of the Pacific herring Clupea pallasii from different parts of the range, from the White Sea to...     

Loktanella soesokkakensis sp. nov., isolated from the junction between the North Pacific Ocean and a freshwater spring

A Gram-negative, aerobic, non-flagellated and rod-shaped or ovoid bacterial strain, designated DSSK1-5^T, was isolated from the junction between the North Pacific Ocean and a freshwater spring at Jeju island, South Korea. Strain DSSK1-5^T was found to grow optimally at 30 °C, at pH 7.0–8.0 and in the presence of 2.0–3.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain DSSK1-5^T fell within the clade comprising Loktanella species, clustering consistently with the type strains of Loktanella hongkongensis and Loktanella cinnabarina, with which it exhibited 98.9 and 98.4 % sequence similarity values, respectively. Sequence similarities to the type strains of the other recognized Loktanella species were 94.0–96.2 %. Strain DSSK1-5^T was found to contain Q-10 as the predominant ubiquinone and C_18:1 ω7c as the major fatty acid. The major polar lipids of strain DSSK1-5^T were identified as phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified glycolipid and one unidentified aminolipid. The DNA G+C content of strain DSSK1-5^T was determined to be 67.6 mol% and its mean DNA–DNA relatedness values with L. hongkongensis JCM 12479^T and L. cinnabarina JCM 18161^T were 19 and 23 %, respectively. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain DSSK1-5^T is separated from other Loktanella species. On the basis of the data presented, strain DSSK1-5^T is proposed to represent a novel species of the genus Loktanella, for which the name Loktanella soesokkakensis sp. nov. is proposed. The type strain is DSSK1-5^T (= KCTC 32425^T = CECT 8367^T).     

Migration of Electronic Energy from Chlorophyll b to Chlorophyll a in Solutions

Absorption, emission, and fluorescence excitation spectra of pure solutions of chlorophyll a (Chl a) and chlorophyll b (Chl b) in diethyl ether and of equimolecular mixed solutions of the two pigments, were determined at room temperature as functions of concentration (in the range from 5 × 10^-6 M to 4 × 10^-3 M) and of wavelength of the exciting light (in the regions 380-465 and 550-650 nm). The efficiency of energy transfer from Chl b to Chl a, derived from these data, was found to depend on the wavelength of exciting light. Furthermore, the transfer efficiency calculated from sensitization of Chl a fluorescence by Chl b was substantially smaller than that calculated from quenching of Chl b fluorescence by Chl a. Both these effects are tentatively explained as evidence of superposition of a “fast” energy transfer (taking place before the Boltzmann distribution of vibrational energy had been reached) upon the “delayed” transfer, which takes place after vibrational equilibration. The first-named mechanism is made possible by overlapping of the absorption bands of the two pigments; the second, by overlapping of the emission band of Chl b and the absorption band of Chl a. The first mechanism can lead to repeated transfer of excitation energy between pigment molecules, the second only to a one-time transfer from the donor to the acceptor. Both mechanisms could be of the same, second-order type, with the transfer rate proportional to r^-6. An alternative is for the fast mechanism to be of the first order, with the transfer rate proportional to r^-3, but spectroscopic evidence seems to make this alternative less probable.     

Diversity and distribution of foliose Bangiales (Rhodophyta) in West Greenland: a link between the North Atlantic and North Pacific

Greenland is a continental island in the northern part of the North Atlantic where the foliose Bangiales flora is poorly known. It is an important area for the study of algal biogeography because of the region’s glacial history, in which Greenland has been alternately exposed to or isolated from the North Pacific via the Bering Strait. A molecular study using 3′ rbcL + 5′ rbcL–S sequences was undertaken to assess the diversity of foliose Bangiales on the west coast of Greenland and rbcL sequences were used to study the Greenland flora in a larger phylogenetic and floristic context. New and historic collections document seven species in four genera from the west coast of Greenland. All species had a close link to North Pacific species, being either conspecific with them or North Atlantic–North Pacific vicariant counterparts.     

Impacts of Interannual Ocean Circulation Variability on Japanese Eel Larval Migration in the Western North Pacific Ocean

The Japanese eel larvae hatch near the West Mariana Ridge seamount chain and travel through the North Equatorial Current (NEC), the Kuroshio, and the Subtropical Countercurrent (STCC) region during their shoreward migration toward East Asia. The interannual variability of circulation over the subtropical and tropical regions of the western North Pacific Ocean is affected by the Philippines–Taiwan Oscillation (PTO). This study examines the effect of the PTO on the Japanese eel larval migration routes using a three-dimensional (3D) particle tracking method, including vertical and horizontal swimming behavior. The 3D circulation and hydrography used for particle tracking are from the ocean circulation reanalysis produced by the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2). Our results demonstrate that bifurcation of the NEC and the strength and spatial variation of the Kuroshio affect the distribution and migration of eel larvae. During the positive phase of PTO, more virtual eels (“v-eels”) can enter the Kuroshio to reach the south coast of Japan and more v-eels reach the South China Sea through the Luzon Strait; the stronger and more offshore swing of the Kuroshio in the East China Sea leads to fewer eels entering the East China Sea and the onshore movement of the Kuroshio to the south of Japan brings the eels closer to the Japanese coast. Significant differences in eel migration routes and distributions regulated by ocean circulation in different PTO phases can also affect the otolith increment. The estimated otolith increment suggests that eel age tends to be underestimated after six months of simulation due to the cooler lower layer temperature. Underestimation is more significant in the positive PTO years due to the wide distribution in higher latitudes than in the negative PTO years.     

Synchronous and time-transgressive Neogene radiolarian datum levels in the Equatorial Indian and Pacific Oceans

Fifty radiolarian events of early Pleistocene and Neogene age were identified in an E-W transect of equatorial DSDP sites, extending from the Gulf of Panama to the western Pacific and eastern Indian Oceans. Our objective was to document the degree of synchroneity or time-transgressiveness of stratigraphically-useful datum levels from this geologic time interval. We restricted our study to low latitudes within which morphological variations of individual taxa are minimal, the total assemblage diversity remains high, and stratigraphic continuity is well-documented by an independent set of criteria. Each of the five sites chosen (503, 573, 289/586, 214) was calibrated to an “absolute” time scale, using a multiple of planktonic foraminiferal, nannofossil, and diatom datum levels which have been independently correlated to the paleomagnetic polarity time scale in piston core material. With these correlations we have assigned “absolute” ages to each radiolarian event, with a precision of 0.1–0.2 m.y. and an accuracy of 0.2–0.4 m.y. On this basis we have classified each of the events as either: (a) synchronous (range of ages <0.4 m.y.); (b) time-transgressive (i.e., range of ages > 1.0 m.y.); and (c) not resolvable (range of ages 0.4–1.0 m.y.).Our results show that, among the synchronous datum levels, a large majority (15 out of 19) are last occurrences. Among those events which are clearly time-transgressive, most are first appearances (10 out of 13). In many instances taxa appear to evolve first in the Indian Ocean, and subsequently in the western and eastern Pacific Ocean. This pattern is particularly unexpected in view of the strong east-to-west zonal flow in equatorial latitudes. Three of the time-transgressive events have been used to define zonal boundaries: the first appearances ofSpongaster pentas, Diartus hughesi, andD. petterssoni. Our results suggest that biostratigraphic non-synchroneity may be substantial (i.e., greater than 1 m.y.) within a given latitudinal zone; one would expect this effect to be even more pronounced across oceanographic and climatic gradients.We anticipate that the extent of diachroneity may be comparable for diatom, foraminiferal, and nannofossil datum levels as well. If this proves true, global “time scales” may need to be re-formulated on the basis of a smaller number of demonstrably synchronous events.     

Diversity and endemism of woody plant species in the Equatorial Pacific seasonally dry forests

The biodiversity hotspot of the Equatorial Pacific region in western Ecuador and northwestern Peru comprises the most extensive seasonally dry forest formations west of the Andes. Based on a recently assembled checklist of the woody plants occurring in this region, we analysed their geographical and altitudinal distribution patterns. The montane seasonally dry forest region (at an altitude between 1,000 and 1,100 m, and the smallest in terms of area) was outstanding in terms of total species richness and number of endemics. The extensive seasonally dry forest formations in the Ecuadorean and Peruvian lowlands and hills (i.e., forests below 500 m altitude) were comparatively much more species poor. It is remarkable though, that there were so many fewer collections in the Peruvian departments and Ecuadorean provinces with substantial mountainous areas, such as Cajamarca and Loja, respectively, indicating that these places have a potentially higher number of species. We estimate that some form of protected area (at country, state or private level) is currently conserving only 5% of the approximately 55,000 km² of remaining SDF in the region, and many of these areas protect vegetation at altitudes below 500 m altitude. In contrast, the more diverse seasonally dry forests in mountainous areas remain little protected.     

The survival of Pacific salmon in the North Pacific in the winter and spring

The effects of various factors (water temperature, food availability, predation, and the size of juveniles) on the survival of Pacific salmons during overwintering in open ocean waters are analyzed based on the data collected by expeditions of the Pacific Research Fisheries Center to the northwestern Pacific Ocean in the winter and spring seasons of 1986–1992 and 2009–2011, as well as in the summer seasons of 2004–2011. The temperature factor is unlikely to be a direct cause of the high salmon mortality in the ocean during the winter, as there is no clear evidence that it affects food availability for salmon. The biomass of forage zooplankton in the Subarctic Front zone in February and March is lower than that in April and June–July, but it does not decrease substantially in the winter months. Taking the fact into account that the total abundance of planktivorous nekton is also low in this area during the winter, food availability cannot be considered a crucial factor that has a serious influence on salmon mortality in this period. The difference in feeding intensity between salmon species and between their size groups in the winter and spring is determined by their life strategies. The observed variations in feeding intensity and lipid accumulation from autumn to spring are caused by cyclic seasonal changes in physiological processes in salmon rather than by the amount and availability of food resources. The low abundance of predators in subarctic waters and in the Subarctic Front zone in the winter also cannot reduce salmon abundance substantially. The probable relationship between the critical size of juveniles and their survival in the winter is considered using the example of a Sea of Okhotsk stock of pink salmon. The conclusion is that the size of juvenile pink salmon cannot always be used as a predictor of the values of its subsequent returns, because survival of salmon during the ocean period of life depends both on the initial conditions during downstream migration and on the ocean conditions that form in the winter. Thus, none of the factors above can be considered as strictly limiting the abundance of Pacific salmon in the winter. It is more probable that the survival of salmon in the ocean is influenced, to a lesser or greater extent, by the combined effects of abiotic and biotic factors.     

Relationship between Chlorophyll a Concentration,Light Attenuation and Diving Depth of the Southern Elephant Seal Mirounga leonina

Recently, a number of Antarctic marine environmental studies have used oceanographic parameters collected from instrumented top predators for ecological and physical information. Phytoplankton concentration is generally quantified through active measurement of chlorophyll fluorescence. In this study, light absorption coefficient (K_0.75) was used as an indicator of phytoplankton concentration. This measurement, easy to obtain and requiring low electric power, allows for assessing of the fine scale horizontal structuring of phytoplankton. As part of this study, Southern elephant seals (SES) were simultaneously equipped with a fluorometer and a light logger. Along the SES tracks, variations in K_0.75 were strongly correlated with chlorophyll, a concentration measured by the fluorometer within the euphotic layer. With regards to SES foraging behaviour, bottom depth of the seal’s dive was highly dependent on light intensity at 150 m, indicating that the vertical distribution of SES’s prey such as myctophids is tightly related to light level. Therefore, change in phytoplankton concentration may not only have a direct effect on SES’s prey abundance but may also determine their vertical accessibility with likely consequences on SES foraging efficiency.