scholarly journals Spatial and temporal variability of the dimethylsulfide to chlorophyll ratio in the surface ocean: an assessment based on phytoplankton group dominance determined from space

2010 ◽  
Vol 7 (10) ◽  
pp. 3215-3237 ◽  
Author(s):  
I. Masotti ◽  
S. Belviso ◽  
S. Alvain ◽  
J. E. Johnson ◽  
T. S. Bates ◽  
...  
Keyword(s):  
Coastal Upwelling ◽  
Spatial Scales ◽  
Horizontal Resolution ◽  
Sea Surface ◽  
Spatial And Temporal Variability ◽  
Phytoplankton Assemblages ◽  
The Pacific ◽  
Significant Difference ◽  
The Difference ◽  
Phytoplankton Group

Abstract. Dimethylsulfoniopropionate (DMSP) is produced in surface seawater by phytoplankton. Phytoplankton culture experiments have shown that nanoeucaryotes (NANO) display much higher mean DMSP-to-Carbon or DMSP-to-Chlorophyll (Chl) ratios than Prochlorococcus (PRO), Synechococcus (SYN) or diatoms (DIAT). Moreover, the DMSP-lyase activity of algae which cleaves DMSP into dimethylsulfide (DMS) is even more group specific than DMSP itself. Ship-based observations have shown at limited spatial scales, that sea surface DMS-to-Chl ratios (DMS:Chl) are dependent on the composition of phytoplankton groups. Here we use satellite remote sensing of Chl (from SeaWiFS) and of Phytoplankton Group Dominance (PGD from PHYSAT) with ship-based sea surface DMS concentrations (8 cruises in total) to assess this dependence on an unprecedented spatial scale. PHYSAT provides PGD (either NANO, PRO, SYN, DIAT, Phaeocystis (PHAEO) or coccolithophores (COC)) in each satellite pixel (1/4° horizontal resolution). While there are identification errors in the PHYSAT method, it is important to note that these errors are lowest for NANO PGD which we typify by high DMSP:Chl. In summer, in the Indian sector of the Southern Ocean, we find that mean DMS:Chl associated with NANO + PHAEO and PRO + SYN + DIAT are 13.6±8.4 mmol g−1 (n=34) and 7.3±4.8 mmol g−1 (n=24), respectively. That is a statistically significant difference (P<0.001) that is consistent with NANO and PHAEO being relatively high DMSP producers. However, in the western North Atlantic between 40° N and 60° N, we find no significant difference between the same PGD. This is most likely because coccolithophores account for the non-dominant part of the summer phytoplankton assemblages. Meridional distributions at 22° W in the Atlantic, and 95° W and 110° W in the Pacific, both show a marked drop in DMS:Chl near the equator, down to few mmol g−1, yet the basins exhibit different PGD (NANO in the Atlantic, PRO and SYN in the Pacific). In tropical and subtropical Atlantic and Pacific waters away from the equatorial and coastal upwelling, mean DMS:Chl associated with high and low DMSP producers are statistically significantly different, but the difference is opposite of that expected from culture experiments. Hence, in a majority of cases PGD is not of primary importance in controlling DMS:Chl variations. We therefore conclude that water-leaving radiance spectra obtained simultaneously from ocean color sensor measurements of Chl concentrations and dominant phytoplankton groups can not be used to predict global fields of DMS.

scholarly journals Do Differences in Latitudinal Distributions of Species and Organelle Haplotypes Reflect Thermal Reaction Norms Within the Emiliania/Gephyrocapsa Complex?

2021 ◽  
Vol 8 ◽  
Author(s):  
Peter von Dassow ◽  
Paula Valentina Muñoz Farías ◽  
Sarah Pinon ◽  
Esther Velasco-Senovilla ◽  
Simon Anguita-Salinas
Keyword(s):  
Local Adaptation ◽  
Coastal Upwelling ◽  
Environmental Gradients ◽  
Reaction Norm ◽  
Emiliania Huxleyi ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Thermal Niche ◽  
Significant Difference ◽  
The Difference

The cosmopolitan phytoplankter Emiliania huxleyi contrasts with its closest relatives that are restricted to narrower latitudinal bands, making it interesting for exploring how alternative outcomes in phytoplankton range distributions arise. Mitochondrial and chloroplast haplogroups within E. huxleyi are shared with their closest relatives: Some E. huxleyi share organelle haplogroups with Gephyrocapsa parvula and G. ericsonii which inhabit lower latitudes, while other E. huxleyi share organelle haplogroups with G. muellerae, which inhabit high latitudes. We investigated whether the phylogeny of E. huxleyi organelles reflects environmental gradients, focusing on the Southeast Pacific where the different haplogroups and species co-occur. There was a high congruence between mitochondrial and chloroplast haplogroups within E. huxleyi. Haplogroup II of E. huxleyi is negatively associated with cooler less saline waters, compared to haplogroup I, both when analyzed globally and across temporal variability at the small special scale of a center of coastal upwelling at 30° S. A new mitochondrial haplogroup Ib detected in coastal Chile was associated with warmer waters. In an experiment focused on inter-species comparisons, laboratory-determined thermal reaction norms were consistent with latitudinal/thermal distributions of species, with G. oceanica exhibiting warm thermal optima and tolerance and G. muellerae exhibiting cooler thermal optima and tolerances. Emiliania huxleyi haplogroups I and II tended to exhibit a wider thermal niche compared to the other Gephyrocapsa, but no differences among haplogroups within E. huxleyi were found. A second experiment, controlling for local adaptation and time in culture, found a significant difference between E. huxleyi haplogroups. The difference between I and II was of the expected sign, but not the difference between I and Ib. The differences were small (≤1°C) compared to differences reported previously within E. huxleyi by local adaptation and even in-culture evolution. Haplogroup Ib showed a narrower thermal niche. The cosmopolitanism of E. huxleyi might result from both wide-spread generalist phenotypes and specialist phenotypes, as well as a capacity for local adaptation. Thermal reaction norm differences can well explain the species distributions but poorly explain distributions among mitochondrial haplogroups within E. huxleyi. Perhaps organelle haplogroup distributions reflect historical rather than selective processes.

scholarly journals High-Resolution Sea Surface Temperatures Derived from Landsat 8: A Study of Submesoscale Frontal Structures on the Pacific Shelf off the Hokkaido Coast, Japan

2020 ◽  
Vol 12 (20) ◽  
pp. 3326
Author(s):  
Hiroshi Kuroda ◽  
Yuko Toya
Keyword(s):  
Spatial Distribution ◽  
Ocean Model ◽  
Sea Surface ◽  
Basic Question ◽  
Landsat 8 ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
The Pacific ◽  
The Difference

Coastal and offshore waters are generally separated by a barrier or “ocean front” on the continental shelf. A basic question arises as to what the representative spatial scale across the front may be. To answer this question, we simply corrected skin sea surface temperatures (SSTs) estimated from Landsat 8 imagery with a resolution of 100 m using skin SSTs estimated from geostationary meteorological satellite Himawari 8 with a resolution of 2 km. We analyzed snapshot images of skin SSTs on 13 October 2016, when we performed a simultaneous ship survey. We focused in particular on submesoscale thermal fronts on the Pacific shelf off the southeastern coast of Hokkaido, Japan. The overall spatial distribution of skin SSTs was consistent between Landsat 8 and Himawari 8; however, the spatial distribution of horizontal gradients of skin SSTs differed greatly between the two datasets. Some parts of strong fronts on the order of 1 °C km−1 were underestimated with Himawari 8, mainly because of low resolution, whereas weak fronts on the order of 0.1 °C km−1 were obscured in the Landsat 8 imagery because the signal-to-noise ratios were low. The widths of the strong fronts were estimated to be 114–461 m via Landsat 8 imagery and 539–1050 m via in situ ship survey. The difference was probably attributable to the difference in measurement depth of the SST, i.e., about 10-μm skin layer by satellite and a few dozen centimeters below the sea surface by the in situ survey. Our results indicated that an ocean model with a grid size of no more than ≤100–200 m is essential for realistic simulation of the frontal structure on the shelf.

scholarly journals Analysis of an intense bora event in the Adriatic area

2004 ◽  
Vol 4 (2) ◽  
pp. 323-337 ◽  
Author(s):  
D. Cesini ◽  
S. Morelli ◽  
F. Parmiggiani
Keyword(s):  
Satellite Data ◽  
Initial Conditions ◽  
Atmospheric Model ◽  
Horizontal Resolution ◽  
Sea Surface ◽  
Temperature Fields ◽  
Sea Surface Temperatures ◽  
Low Level ◽  
Surface Temperatures ◽  
The Difference

Abstract. Numerical simulations of a bora event, recently occurred in the Adriatic area, are presented. Two reference runs at different horizontal resolution (about 20km and 8km) describe the case. Initial conditions for the atmospheric model integration are obtained from ECMWF analyses. Satellite data are used for comparisons. A further run at horizontal resolution of 8km, using initial satellite sea surface temperatures, is performed to evaluate their impact on the low level wind over the Adriatic Sea. All the simulations are carried out with 50 layers in the vertical. Numerous aspects of the simulations are found to be in agreement with the understanding as well as the observational knowledge of bora distinctive characteristics. Satellite data and model results indicate that a more realistic simulation of the bora wind over the sea is achieved using the model with 8km horizontal resolution and that the low level wind in this case is sensitive, though weakly, to the difference between the used sea surface temperature fields. Simulation results also show that both wind intensity and the area around wind peaks tend to increase when relatively higher sea surface temperatures are used.

Opposite effects of ocean temperature on survival rates of 120 stocks of Pacific salmon (Oncorhynchus spp.) in northern and southern areas

2002 ◽  
Vol 59 (3) ◽  
pp. 456-463 ◽  
Author(s):  
Franz J Mueter ◽  
Randall M Peterman ◽  
Brian J Pyper
Keyword(s):  
Large Scale ◽  
Pacific Salmon ◽  
Spatial Scales ◽  
Regional Scale ◽  
Survival Rates ◽  
Climatic Changes ◽  
Sea Surface ◽  
Ocean Temperature ◽  
Climate Anomalies ◽  
The Pacific

To improve the understanding of linkages between ocean conditions and salmon productivity, we estimated effects of ocean temperature on survival rates of three species of Pacific salmon (Oncorhynchus spp.) across 120 stocks. This multistock approach permitted more precise estimates of effects than standard single-stock analyses. The estimated effects were opposite in sign between northern and southern stocks and were quite consistent across stocks within species and areas. Warm anomalies in coastal temperatures were associated with increased survival rates for stocks in Alaska and decreased survival rates in Washington and British Columbia, suggesting that different mechanisms determine survival rates in the two areas. Regional-scale sea surface temperatures (SST, within several hundred kilometres of a stock's ocean entry point) were a much better predictor of survival rates than large-scale climate anomalies associated with the Pacific Decadal Oscillation (PDO), suggesting that survival rates are primarily linked to environmental conditions at regional spatial scales. With appropriate cautions, these results may be used to predict the potential effects of climatic changes on salmon productivity in different areas of the Northeast Pacific.

scholarly journals Predictability of non-phase-locked baroclinic tides in the Caribbean Sea

Ocean Science ◽  
2019 ◽  
Vol 15 (5) ◽  
pp. 1287-1305
Author(s):  
Edward D. Zaron
Keyword(s):  
Sea Level ◽  
Forecast Error ◽  
Caribbean Sea ◽  
Forecast Model ◽  
Sea Surface ◽  
Spatial And Temporal Variability ◽  
Tide Gauges ◽  
Sea Level Anomalies ◽  
The Caribbean ◽  
The Difference

Abstract. The predictability of the sea surface height expression of baroclinic tides is examined with 96 h forecasts produced by the AMSEAS operational forecast model during 2013–2014. The phase-locked tide, both barotropic and baroclinic, is identified by harmonic analysis of the 2-year record and found to agree well with observations from tide gauges and satellite altimetry within the Caribbean Sea. The non-phase-locked baroclinic tide, which is created by time-variable mesoscale stratification and currents, may be identified from residual sea level anomalies (SLAs) near the tidal frequencies. The predictability of the non-phase-locked tide is assessed by measuring the difference between a forecast – centered at T+36, T+60, or T+84 h – and the model's later verifying analysis for the same time. Within the Caribbean Sea, where a baroclinic tidal sea level range of ±5 cm is typical, the forecast error for the non-phase-locked tidal SLA is correlated with the forecast error for the subtidal (mesoscale) SLA. Root mean square values of the former range from 0.5 to 2 cm, while the latter ranges from 1 to 6 cm, for a typical 84 h forecast. The spatial and temporal variability of the forecast error is related to the dynamical origins of the non-phase-locked tide and is briefly surveyed within the model.

scholarly journals Radiocarbon Reservoir Age Variations in the South Peruvian Upwelling During the Holocene

Radiocarbon ◽  
2004 ◽  
Vol 46 (2) ◽  
pp. 531-537 ◽  
Author(s):  
Michel Fontugne ◽  
Matthieu Carré ◽  
Ilhem Bentaleb ◽  
Michèle Julien ◽  
Danièle Lavallée
Keyword(s):  
Ocean Circulation ◽  
Coastal Upwelling ◽  
Sea Surface ◽  
Intermediate Depth ◽  
The Holocene ◽  
Middle Holocene ◽  
Age Variations ◽  
The Difference ◽  
Upwelling Intensity ◽  
Reservoir Age

In Quebrada de los Burros in coastal southern Peru (Tacna department), human settlements containing shells and charcoal deposits have been excavated since 1995. The sea surface 14C reservoir ages, estimated by calculating the difference of 14C age between marine shells and terrestrial organic materials, exhibit high values during the lower and middle Holocene and decrease abruptly after 4000 cal BP. The increase of reservoir age at around 7000–8000 cal BP suggests an enhancement of Peruvian coastal upwelling intensity and changes in ocean circulation at intermediate depth.

scholarly journals Predictability of Non-Phase-Locked Baroclinic Tides in the Caribbean Sea

2019 ◽  
Author(s):  
Edward D. Zaron
Keyword(s):  
Sea Level ◽  
Forecast Error ◽  
Caribbean Sea ◽  
Forecast Model ◽  
Sea Surface ◽  
Spatial And Temporal Variability ◽  
Tide Gauges ◽  
Sea Level Anomaly ◽  
The Caribbean ◽  
The Difference

Abstract. The predictability of the sea surface height expression of baroclinic tides is examined with 96 hr forecasts produced by the AMSEAS operational forecast model during 2013–2014. The phase-locked tide, both barotropic and baroclinic, is identified by harmonic analysis of the 2 year record and found to agree well with observations from tide gauges and satellite altimetry within the Caribbean Sea. The non-phase-locked baroclinic tide, which is created by the time-variable mesoscale stratification and currents, may be identified from residual sea level anomaly (SLA) near the tidal frequencies. The predictability of the non-phase-locked tide is assessed by measuring the difference between a forecast – centered at T+36 hr, T+60 hr, or T+84 hr – and the model's later verifying analysis for the same time. Within the Caribbean Sea, where a baroclinic tidal sea level range of ±5 cm is typical, the forecast error for the non-phase-locked tidal SLA is correlated with the forecast error for the sub-tidal (mesoscale) SLA. Root-mean-square values of the former range from 0.5 cm to 2 cm, while the latter ranges from 1 cm to 6 cm, for a typical 84 hr forecast. The spatial and temporal variability of the forecast error is related to the dynamical origins of the non-phase-locked tide and is briefly surveyed within the model.

Cranial crassicaudiasis in two coastal dolphin species from South Africa is predominantly a disease of immature individuals

2020 ◽  
Vol 139 ◽  
pp. 93-102 ◽  
Author(s):  
MF Van Bressem ◽  
P Duignan ◽  
JA Raga ◽  
K Van Waerebeek ◽  
N Fraijia-Fernández ◽  
...  
Keyword(s):  
South Africa ◽  
Bone Development ◽  
Bottlenose Dolphins ◽  
Fatal Outcome ◽  
Population Level ◽  
Cape Coast ◽  
Osteolytic Lesions ◽  
Immune Mediated ◽  
Significant Difference ◽  
The Difference

Crassicauda spp. (Nematoda) infest the cranial sinuses of several odontocetes, causing diagnostic trabecular osteolytic lesions. We examined skulls of 77 Indian Ocean humpback dolphins Sousa plumbea and 69 Indo-Pacific bottlenose dolphins Tursiops aduncus, caught in bather-protecting nets off KwaZulu-Natal (KZN) from 1970-2017, and skulls of 6 S. plumbea stranded along the southern Cape coast in South Africa from 1963-2002. Prevalence of cranial crassicaudiasis was evaluated according to sex and cranial maturity. Overall, prevalence in S. plumbea and T. aduncus taken off KZN was 13 and 31.9%, respectively. Parasitosis variably affected 1 or more cranial bones (frontal, pterygoid, maxillary and sphenoid). No significant difference was found by gender for either species, allowing sexes to be pooled. However, there was a significant difference in lesion prevalence by age, with immature T. aduncus 4.6 times more likely affected than adults, while for S. plumbea, the difference was 6.5-fold. As severe osteolytic lesions are unlikely to heal without trace, we propose that infection is more likely to have a fatal outcome for immature dolphins, possibly because of incomplete bone development, lower immune competence in clearing parasites or an over-exuberant inflammatory response in concert with parasitic enzymatic erosion. Cranial osteolysis was not observed in mature males (18 S. plumbea, 21 T. aduncus), suggesting potential cohort-linked immune-mediated resistance to infestation. Crassicauda spp. may play a role in the natural mortality of S. plumbea and T. aduncus, but the pathogenesis and population level impact remain unknown.

Perbedaan Penggunaan Antikoagulan K2EDTA DAN K3EDTA Terhadap Hasil Pemeriksaan Indeks Eritrosit

2018 ◽  
Vol 1 (2) ◽  
pp. 114
Author(s):  
Wahdaniah Wahdaniah ◽  
Sri Tumpuk
Keyword(s):  
Screening Test ◽  
Venous Blood ◽  
The Body ◽  
Ethylene Diamine ◽  
P Value ◽  
Cross Sectional ◽  
Significant Difference ◽  
Ethylene Diamine Tetra Acetate ◽  
The Difference ◽  
Index Value

Abstract: Routine blood examination is the earliest blood test or screening test to determine the diagnosis of an abnormality. Blood easily froze if it is outside the body and can be prevented by the addition of anticoagulants, one of which Ethylene Diamine Tetra Acetate (EDTA). Currently available vacuum tubes containing EDTA anticoagulants in the form of K2EDTA and K3EDTA. K3EDTA is usually a salt that has better stability than other EDTA salts because it shows a pH approaching a blood pH of about 6.4. The purpose of this research is to know the difference of erythrocyte index results include MCH, MCV and MCHC using K3EDTA anticoagulant with K2EDTA. This research is a cross sectional design. This study used venous blood samples mixed with K2EDTA anticoagulant and venous blood mixed with K3EDTA anticoagulants, each of 30 samples. Data were collected and analyzed using paired different test. Based on data analysis that has been done on MCH examination, p value <0,05 then there is a significant difference between samples with K3EDTA anticoagulant with K2EDTA to erythrocyte index value. Then on the examination of MCV and MCHC obtained p value <0.05 then there is no significant difference between samples with K3EDTA anticoagulant with K2EDTA to erythrocyte index value.Abstrak: Pemeriksaan darah rutin merupakan pemeriksaan darah yang paling awal atau screening test untuk mengetahui diagnosis suatu kelainan. Darah mudah membeku jika berada diluar tubuh dan bisa dicegah dengan penambahan antikoagulan, salah satunya Ethylene Diamine Tetra Acetate (EDTA). Dewasa ini telah tersedia tabung vakum yang sudah berisi antikoagulan EDTA dalam bentuk  K2EDTA dan  K3EDTA. K3EDTA  biasanya berupa garam yang mempunyai stabilitas yang lebih baik dari garam EDTA yang lain karena menunjukkan pH yang mendekati pH darah yaitu sekitar 6,4. Tujuan dari penelitian ini adalah untuk mengetahui perbedaan hasil indeks eritrosit meliputi MCH, MCV dan MCHC menggunakan antikoagulan K3EDTA dengan K2EDTA. Penelitian ini merupakan penelitian dengan desain cross sectional. Penelitian ini menggunakan sampel darah vena yang dicampur dengan antikoagulan K2EDTA dan darah vena yang dicampur dengan antikoagulan K3EDTA, masing-masing sebanyak 30 sampel. Data dikumpulkan dan dianalisis menggunakan uji beda berpasangan. Berdasarkan analisis data yang telah dilakukan pada pemeriksaan MCH didapatkan nilai p < 0,05 maka ada perbedaan yang signifikan antara sampel dengan antikoagulan K3EDTA dengan K2EDTA terhadap nilai indeks eritrosit. Kemudian pada pemeriksaan MCV dan MCHC didapatkan nilai p < 0,05 maka tidak ada perbedaan yang signifikan antara sampel dengan antikoagulan K3EDTA dengan K2EDTA terhadap nilai indeks eritrosit.

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