Occurrence of Chromadorita regabi sp. nov. (Nematoda: Adenophorea), a nematode egg predator of Alvinocaris muricola (Crustacea: Decapoda: Caridea: Alvinocarididae) from a deep cold seep area of the Gulf of Guinea

Three new phenylhydrazones, penoxahydrazones A–C (compounds 1–3), and two new quinazolines, penoxazolones A (compound 4) and B (compound 5), with unique linkages were isolated from the fungus Penicillium oxalicum obtained from the deep sea cold seep. Their structures and relative configurations were assigned by analysis of 1D/2D NMR and mass spectroscopic data, and the absolute configurations of 1, 4, and 5 were established on the basis of X-ray crystallography or ECD calculations. Compound 1 represents the first natural phenylhydrazone-bearing steroid, while compounds 2 and 3 are rarely occurring phenylhydrazone tautomers. Compounds 4 and 5 are enantiomers that feature quinazoline and cinnamic acid units. Some isolates exhibited inhibition of several marine phytoplankton species and marine-derived bacteria.

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Taxonomic revision of the Jita snakes (Lamprophiidae: Boaedon) from São Tomé and Príncipe (Gulf of Guinea), with the description of a new species

African Journal of Herpetology ◽

10.1080/21564574.2020.1832152 ◽

2021 ◽

pp. 1-31

Author(s):

Luis MP Ceríaco ◽

Ana Lisette Arellano ◽

Robert C Jadin ◽

Mariana P Marques ◽

Diogo Parrinha ◽

...

Keyword(s):

New Species ◽

Taxonomic Revision ◽

Gulf Of Guinea ◽

Sao Tome And Principe ◽

A New Species

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Understanding the variability of the rainfall dipole in West Africa using the EC-Earth last millennium simulation

Climate Dynamics ◽

10.1007/s00382-021-05696-x ◽

2021 ◽

Author(s):

Qiong Zhang ◽

Ellen Berntell ◽

Qiang Li ◽

Fredrik Charpentier Ljungqvist

Keyword(s):

West Africa ◽

Model Simulation ◽

Rainfall Variability ◽

Low Pressure ◽

Last Millennium ◽

Tropical Atlantic ◽

Gulf Of Guinea ◽

Dipole Pattern ◽

Sahel Region ◽

Heat Low

AbstractThere is a well-known mode of rainfall variability associating opposite hydrological conditions over the Sahel region and the Gulf of Guinea, forming a dipole pattern. Previous meteorological observations show that the dipole pattern varies at interannual timescales. Using an EC-Earth climate model simulation for last millennium (850–1850 CE), we investigate the rainfall variability in West Africa over longer timescales. The 1000-year-long simulation data show that this rainfall dipole presents at decadal to multidecadal and centennial variability and long-term trend. Using the singular value decomposition (SVD) analysis, we identified that the rainfall dipole present in the first SVD mode with 60% explained variance and associated with the variabilities in tropical Atlantic sea surface temperature (SST). The second SVD mode shows a monopole rainfall variability pattern centred over the Sahel, associated with the extra-tropical Atlantic SST variability. We conclude that the rainfall dipole-like pattern is a natural variability mode originated from the local ocean–atmosphere-land coupling in the tropical Atlantic basin. The warm SST anomalies in the equatorial Atlantic Ocean favour an anomalous low pressure at the tropics. This low pressure weakens the meridional pressure gradient between the Saharan Heat Low and the tropical Atlantic. It leads to anomalous northeasterly, reduces the southwesterly moisture flux into the Sahel and confines the Gulf of Guinea's moisture convergence. The influence from extra-tropical climate variability, such as Atlantic multidecadal oscillation, tends to modify the rainfall dipole pattern to a monopole pattern from the Gulf of Guinea to Sahara through influencing the Sahara heat low. External forcing—such as orbital forcing, solar radiation, volcanic and land-use—can amplify/dampen the dipole mode through thermal forcing and atmosphere dynamical feedback.

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Development of an Easy-to-Operate Underwater Raman System for Deep-Sea Cold Seep and Hydrothermal Vent In Situ Detection

Sensors ◽

10.3390/s21155090 ◽

2021 ◽

Vol 21 (15) ◽

pp. 5090

Author(s):

Qingsheng Liu ◽

Jinjia Guo ◽

Wangquan Ye ◽

Kai Cheng ◽

Fujun Qi ◽

...

Keyword(s):

Deep Sea ◽

Hydrothermal Vent ◽

Methane Hydrate ◽

Sulfur Cycle ◽

Cold Seep ◽

Remotely Operated Vehicle ◽

Bacterial Mats ◽

Optical Module ◽

In Situ Detection

As a powerful in situ detection technique, Raman spectroscopy is becoming a popular underwater investigation method, especially in deep-sea research. In this paper, an easy-to-operate underwater Raman system with a compact design and competitive sensitivity is introduced. All the components, including the optical module and the electronic module, were packaged in an L362 × Φ172 mm titanium capsule with a weight of 20 kg in the air (about 12 kg in water). By optimising the laser coupling mode and focusing lens parameters, a competitive sensitivity was achieved with the detection limit of SO42− being 0.7 mmol/L. The first sea trial was carried out with the aid of a 3000 m grade remotely operated vehicle (ROV) “FCV3000” in October 2018. Over 20,000 spectra were captured from the targets interested, including methane hydrate, clamshell in the area of cold seep, and bacterial mats around a hydrothermal vent, with a maximum depth of 1038 m. A Raman peak at 2592 cm−1 was found in the methane hydrate spectra, which revealed the presence of hydrogen sulfide in the seeping gas. In addition, we also found sulfur in the bacterial mats, confirming the involvement of micro-organisms in the sulfur cycle in the hydrothermal field. It is expected that the system can be developed as a universal deep-sea survey and detection equipment in the near future.

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