scholarly journals Diazotrophic <i>Trichodesmium</i> influence on ocean color and pigment composition in the South West tropical Pacific

2018 ◽  
Author(s):  
Cécile Dupouy ◽  
Robert Frouin ◽  
Marc Tedetti ◽  
Morgane Maillard ◽  
Martine Rodier ◽  
...  
Keyword(s):  
High Performance ◽  
New Caledonia ◽  
Principal Component ◽  
Euphotic Zone ◽  
Tropical Pacific ◽  
The South ◽  
South West ◽  
Underwater Vision ◽  
Fiji Islands ◽  
High Fluorescence

Abstract. We assessed the influence of the marine diazotrophic cyanobacterium Trichodesmium on the bio-optical properties of South West tropical Pacific waters (18–22° S, 160° E–160° W) during the February–March 2015 OUTPACE cruise. We performed measurements of backscattering and absorption coefficients, irradiance, and radiance, in the euphotic zone, and took Underwater Vision Profiler 5 (UPV5) pictures for counting the largest Trichodesmium spp. colonies. Pigment concentrations were determined by fluorimetry and by high performance liquid chromatography and picoplankton abundance by flow cytometry. Trichome concentration was estimated from pigment algorithms and validated by surface visual counts. In result, the large colonies were well correlated to the trichome concentration estimates (though with a large factor of 600 to 900, due to aggregation processes). Large Trichodesmium abundance was always associated with particulate absorption at a peak of mycosporine-like amino acid absorption, and high particulate backscattering, but not with high fluorescence, high chlorophyll-a concentration, or blue particulate absorption in the water column. Along the West to East transect, Trichodesmium together with Prochlorococcus represented the major part of total chlorophyll and the other groups were negligible. Trichodesmium contribution to chlorophyll was the highest in the Melanesian Archipelago around New Caledonia and Vanuatu, progressively decreased to the vicinity of the Fiji Islands, and reached a minimum in the South Pacific gyre where the contribution of Prochlorococcus was maximum. At the frontal LDB, Trichodesmium and Prochlorococcus has almost same contributions. The relationship between normalized water-leaving radiance, in the ultraviolet and visible domains, nLw, and chlorophyll was generally similar to that found in the Eastern tropical at BIOSOPE. Principal component analysis (PCA) of OUTPACE data showed that nLw were strongly correlated to chlorophyll except in the green and yellow domains. These results, as well as differences in the PCA of BIOSOPE data, suggested that nLw variability in the green and yellow during OUTPACE was influenced by other variables, associated with Trichodesmium presence as the backscattering coefficient, phycoerythrin fluorescence, and/or zeaxanthin absorption. Trichodesmium detection should then involve examination of nLw at the green and yellow wavelengths.

scholarly journals Diazotrophic <i>Trichodesmium</i> impact on UV–Vis radiance and pigment composition in the western tropical South Pacific

2018 ◽  
Vol 15 (16) ◽  
pp. 5249-5269 ◽  
Author(s):  
Cécile Dupouy ◽  
Robert Frouin ◽  
Marc Tedetti ◽  
Morgane Maillard ◽  
Martine Rodier ◽  
...  
Keyword(s):  
High Performance ◽  
New Caledonia ◽  
Chlorophyll Concentration ◽  
Principal Component ◽  
Euphotic Zone ◽  
South Pacific ◽  
Free Fall ◽  
Total Chlorophyll ◽  
Chl A ◽  
Underwater Vision

Abstract. We assessed the influence of the marine diazotrophic cyanobacterium Trichodesmium on the bio-optical properties of western tropical South Pacific (WTSP) waters (18–22∘ S, 160∘ E–160∘ W) during the February–March 2015 OUTPACE cruise. We performed measurements of backscattering and absorption coefficients, irradiance, and radiance in the euphotic zone with a Satlantic MicroPro free-fall profiler and took Underwater Vision Profiler 5 (UPV5) pictures for counting the largest Trichodesmium spp. colonies. Pigment concentrations were determined by fluorimetry and high-performance liquid chromatography and picoplankton abundance by flow cytometry. Trichome concentration was estimated from pigment algorithms and validated by surface visual counts. The abundance of large colonies counted by the UVP5 (maximum 7093 colonies m−3) was well correlated to the trichome concentrations (maximum 2093 trichomes L−1) with an aggregation factor of 600. In the Melanesian archipelago, a maximum of 4715 trichomes L−1 was enumerated in pump samples (3.2 m) at 20∘ S, 167 30∘ E. High Trichodesmium abundance was always associated with absorption peaks of mycosporine-like amino acids (330, 360 nm) and high particulate backscattering, but not with high Chl a fluorescence or blue particulate absorption (440 nm). Along the west-to-east transect, Trichodesmium together with Prochlorococcus represented the major part of total chlorophyll concentration; the contribution of other groups were relatively small or negligible. The Trichodesmium contribution to total chlorophyll concentration was the highest in the Melanesian archipelago around New Caledonia and Vanuatu (60 %), progressively decreased to the vicinity of the islands of Fiji (30 %), and reached a minimum in the South Pacific Gyre where Prochlorococcus dominated chlorophyll concentration. The contribution of Trichodesmium to zeaxanthin was respectively 50, 40 and 20 % for these regions. During the OUTPACE cruise, the relationship between normalized water-leaving radiance (nLw) in the ultraviolet and visible and chlorophyll concentration was similar to that found during the BIOSOPE cruise in the eastern tropical Pacific. Principal component analysis (PCA) of OUTPACE data showed that nLw at 305, 325, 340, 380, 412 and 440 nm was strongly correlated to chlorophyll and zeaxanthin, while nLw at 490 and 565 nm exhibited lower correlations. These results, as well as differences in the PCA of BIOSOPE data, indicated that nLw variability in the greenish blue and yellowish green during OUTPACE was influenced by other variables associated with Trichodesmium presence, such as backscattering coefficient, phycoerythrin fluorescence and/or zeaxanthin absorption, suggesting that Trichodesmium detection should involve examination of nLw in this spectral domain.

scholarly journals An algorithm for detecting <i>Trichodesmium</i> surface blooms in the South Western Tropical Pacific

2011 ◽  
Vol 8 (12) ◽  
pp. 3631-3647 ◽  
Author(s):  
C. Dupouy ◽  
D. Benielli-Gary ◽  
J. Neveux ◽  
Y. Dandonneau ◽  
T. K. Westberry
Keyword(s):  
Co2 Sequestration ◽  
New Caledonia ◽  
Tropical Pacific ◽  
The South ◽  
Western Tropical Pacific ◽  
Tropical Oceans ◽  
Fiji Islands ◽  
C And N ◽  
In Situ Observations

Abstract. Trichodesmium, a major colonial cyanobacterial nitrogen fixer, forms large blooms in NO3-depleted tropical oceans and enhances CO2 sequestration by the ocean due to its ability to fix dissolved dinitrogen. Thus, its importance in C and N cycles requires better estimates of its distribution at basin to global scales. However, existing algorithms to detect them from satellite have not yet been successful in the South Western Tropical Pacific (SP). Here, a novel algorithm (TRICHOdesmium SATellite) based on radiance anomaly spectra (RAS) observed in SeaWiFS imagery, is used to detect Trichodesmium during the austral summertime in the SP (5° S–25° S 160° E–170° W). Selected pixels are characterized by a restricted range of parameters quantifying RAS spectra (e.g. slope, intercept, curvature). The fraction of valid (non-cloudy) pixels identified as Trichodesmium surface blooms in the region is low (between 0.01 and 0.2 %), but is about 100 times higher than deduced from previous algorithms. At daily scales in the SP, this fraction represents a total ocean surface area varying from 16 to 48 km2 in Winter and from 200 to 1000 km2 in Summer (and at monthly scale, from 500 to 1000 km2 in Winter and from 3100 to 10 890 km2 in Summer with a maximum of 26 432 km2 in January 1999). The daily distribution of Trichodesmium surface accumulations in the SP detected by TRICHOSAT is presented for the period 1998–2010 which demonstrates that the number of selected pixels peaks in November–February each year, consistent with field observations. This approach was validated with in situ observations of Trichodesmium surface accumulations in the Melanesian archipelago around New Caledonia, Vanuatu and Fiji Islands for the same period.

Larval trypanorhynch cestodes in teleost fish from Moreton Bay, Queensland

2017 ◽  
Vol 68 (11) ◽  
pp. 2123 ◽  
Author(s):  
I. Beveridge ◽  
T. H. Cribb ◽  
S. C. Cutmore
Keyword(s):  
Host Species ◽  
Teleost Fish ◽  
New Caledonia ◽  
The South ◽  
West Pacific ◽  
Moreton Bay ◽  
South West ◽  
Lizard Island ◽  
The World

During a helminthological examination of teleost fish of Moreton Bay (Qld, Australia), 976 fish from 13 orders, 57 families and 133 species were examined and nine species of trypanorhynch metacestodes were identified. Callitetrarhynchus gracilis (Rudolphi, 1819) was the most frequently encountered species, found in 16 species of fish, with Callitetrarhynchus speciosus (Linton, 1897), Pterobothrium pearsoni (Southwell, 1929), Otobothrium alexanderi Palm, 2004, Otobothrium mugilis Hiscock, 1954, Otobothrium parvum Beveridge & Justine, 2007, Proemotobothrium southwelli Beveridge & Campbell, 2001, Pseudotobothrium dipsacum (Linton, 1897) and Heteronybelinia cf. heteromorphi Palm, 1999 occurring in fewer host species and at lower prevalences. Comparisons are made with studies elsewhere in the world and specifically within the South-west Pacific. Of the best studied regions in the South-west Pacific (Heron Island, Lizard Island, New Caledonia and now Moreton Bay), the fauna from Moreton Bay was found to be the most distinctive, with fauna from the three reef locations sharing 35–48% of species between sites and just 12–24% with Moreton Bay. The fauna of trypanorhynch cestodes from Lizard Island and New Caledonia was found to be the most similar.

scholarly journals Wind-induced variability in larval retention in a coral reef system: A biophysical modelling study in the South-West Lagoon of New Caledonia

2014 ◽  
Vol 122 ◽  
pp. 105-115 ◽  
Author(s):  
Marion Cuif ◽  
David Michael Kaplan ◽  
Jérôme Lefèvre ◽  
Vincent Martin Faure ◽  
Matthieu Caillaud ◽  
...  
Keyword(s):  
Coral Reef ◽  
New Caledonia ◽  
The South ◽  
Larval Retention ◽  
Reef System ◽  
System A ◽  
South West ◽  
Coral Reef System ◽  
Modelling Study ◽  
Biophysical Modelling

One New Genus and Four New Species of Terrestrial Mesoveliidae (Hemiptera: Gerromorpha) from Australia and New Caledonia

1983 ◽  
Vol 31 (6) ◽  
pp. 943 ◽  
Author(s):  
MB Malipatil ◽  
GB Monteith
Keyword(s):  
New Species ◽  
Type Species ◽  
New Genus ◽  
New Caledonia ◽  
The South ◽  
Altitudinal Distribution ◽  
West Pacific ◽  
South West ◽  
Generalized Distribution

Austrovelia, gen. nov. (type-species A. queenslandica, sp. nov., from North Queensland), A. caledonica, sp. nov. (from New Caledonia), and Phrynovelia caledonica, sp. nov., and P. bimaculata, sp. nov. (both from New Caledonia) are described and compared with related known genera and species. Altitudinal distribution of A, queenslandica and biogeographic affinities between New Caledonia and the Mount Sorrow tableland in North Queensland are discussed, and a generalized distribution of terrestrial Mesoveliidae in the south-west Pacific is given.

Distribution of phyllosoma larvae of Scyllaridae and Palinuridae (Decapoda : Palinuridea) in the south-western lagoon of New Caledonia

2000 ◽  
Vol 51 (4) ◽  
pp. 363 ◽  
Author(s):  
Emmanuel Coutures
Keyword(s):  
Larval Development ◽  
New Caledonia ◽  
Coastal Areas ◽  
The Other ◽  
Stage I ◽  
Barrier Reef ◽  
The South ◽  
Outer Slope ◽  
South West ◽  
Phyllosoma Larvae

Densities of phyllosomata of Panulirus, Scyllarides, Parribacus and Scyllarus were measured by plankton sampling in November–December 1996 and 1997 in the lagoon, in a passage through the barrier reef and above the outer slope to the south-west of New Caledonia. A total of 1017 phyllosomata were caught: 584 Panulirus, 66 Scyllarides, 6 Parribacus and 361 Scyllarus. More phyllosomata of Scyllarus spp. were caught in the lagoon than at the other two sites. The larval development of certain Scyllarus species can occur entirely in the lagoon, but morphology of the early stages of the four Scyllarus species caught here was too similar to permit conclusions about specific strategies. Phyllosomata of the Panulirus spp., Scyllarides spp. and Parribacus spp. develop only in the ocean. High densities of Stage I of Panulirus ornatus larvae caught in the passage and nearby ocean suggested that the reproductive adults of this species migrate from coastal areas towards more oceanic areas to hatch their phyllosomata. Stage I phyllosomata of Panulirus and Scyllarides were near the surface and would be carried quickly from the lagoon by the current, whereas this behaviour was not shown for Stage I phyllosomata of Scyllarus sp., and this would probably limit their passive wind drifting.

Nomenclatural and type catalogue of Athoracophoridae (Mollusca: Eupulmonata: Succineoidea): a synopsis of the first 185 years of biodiscovery in the South West Pacific region

Zootaxa ◽  
2018 ◽  
Vol 4434 (2) ◽  
pp. 201
Author(s):  
GARY M. BARKER
Keyword(s):  
New Caledonia ◽  
Species Group ◽  
The South ◽  
Systematic Revision ◽  
West Pacific ◽  
South West ◽  
Systematic Effort ◽  
The Family ◽  
Biogeographic Region ◽  
Faunal Element

Athoracophoridae are succineoidean terrestrial slugs that constitute a distinctive faunal element of the South West Pacific biogeographic region, with representatives in New Guinea, Australia, New Caledonia, Vanuatu and New Zealand. Despite many studies on morphology, taxonomy and phylogenetic relationships since the first species description in 1832, the understanding of the diversity within the family, as reported in published literature, remains poor with regional disparities in collection and systematic effort, in taxonomic concepts, and in adherence to type concepts. The systematics of Athoracophoridae needs to be re-evaluated through a modern, phylogenetic approach to properly document infra-familial evolution and taxon diversity, advance understanding of evolutionary relationships with other Eupulmonata, and to delineate evolutionary units for conservation prioritization. A catalogue of all class-, family-, genus- and species-group names erected for or used to include Athoracophoridae over the 185 year period 1832 to 2017 is provided, as a first step towards a systematic revision. The following nomenclatural changes are made: lectotype designation for Aneitea macdonaldii Gray, 1860; lectotype designation for Janella papillata Hutton, 1879; type species designation for Amphikonophora Suter, 1897; and lectotype designation for Athoracophorus verrucosus Simroth, 1889. 

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