Benthic oxygen fluxes in a coastal upwelling system (Ria de Vigo, NW Iberia) measured by aquatic eddy covariance

Organic carbon mineralization and nutrient cycling in benthic environments are critically important for their biogeochemical functioning, but are poorly understood in coastal up - welling systems. The main objective of this study was to determine benthic oxygen fluxes in a muddy sediment in the Ria de Vigo (NW Iberian coastal upwelling), by applying the aquatic eddy covariance (AEC) technique during 2 campaigns in different seasons (June and October 2017). The main drivers of benthic fluxes were studied and compared among days in each season and between seasons. The 2 campaigns were characterized by an upwelling-relaxation period followed by a downwelling event, the last of which was due to the extratropical cyclone Ophelia in October. The mean (±SD) seasonal benthic oxygen fluxes were not significantly different for the 2 campaigns despite differences in hydrodynamic and biogeochemical conditions (June: -20.9 ± 7.1 mmol m-2d-1vs. October: -26.5 ± 3.1 mmol m-2d-1). Benthic fluxes were controlled by different drivers depending on the season. June was characterized by sinking labile organic material, which enhanced benthic fluxes in the downwelling event, whereas October had a significantly higher bottom velocity that stimulated the benthic fluxes. Finally, a comparison with a large benthic chamber (0.50 m2) was made during October. Despite methodological differences between AEC and chamber measurements, concurrent fluxes agreed within an acceptable margin (AEC:benthic chamber ratio = 0.78 ± 0.13; mean ± SD). Bottle incubations of water sampled from the chamber interior indicated that mineralization could explain this difference. These results show the importance of using non-invasive techniques such as AEC to resolve benthic flux dynamicsPostprin

Study of B0(s)→K0Sh+h′− decays with first observation of B0s→K0SK±π∓ and B0s→K0Sπ+π−

A search for charmless three-body decays of B 0 and B0s mesons with a K0S meson in the final state is performed using the pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of 7 TeV recorded by the LHCb experiment. Branching fractions of the B0(s)→K0Sh+h′− decay modes (h (′) = π, K), relative to the well measured B0→K0Sπ+π− decay, are obtained. First observation of the decay modes B0s→K0SK±π∓ and B0s→K0Sπ+π− and confirmation of the decay B0→K0SK±π∓ are reported. The following relative branching fraction measurements or limits are obtained B(B0→K0SK±π∓)B(B0→K0Sπ+π−)=0.128±0.017(stat.)±0.009(syst.), B(B0→K0SK+K−)B(B0→K0Sπ+π−)=0.385±0.031(stat.)±0.023(syst.), B(B0s→K0Sπ+π−)B(B0→K0Sπ+π−)=0.29±0.06(stat.)±0.03(syst.)±0.02(fs/fd), B(B0s→K0SK±π∓)B(B0→K0Sπ+π−)=1.48±0.12(stat.)±0.08(syst.)±0.12(fs/fd)B(B0s→K0SK+K−)B(B0→K0Sπ+π−)∈[0.004;0.068]at90%CL

Study of DJ meson decays to D+π−, D0π+ and D∗+π− final states in pp collisions

A study of D+π−, D0π+ and D∗+π− final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The D1(2420)0 resonance is observed in the D∗+π− final state and the D∗2(2460) resonance is observed in the D+π−, D0π+ and D∗+π− final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the D∗+π−, D+π− and D0π+ final states

First observation of the decay Bˉs0→D0K∗0\bar{B}^0_s \to D^0 K^{*0} and a measurement of the ratio of branching fractions B(Bˉs0→D0K∗0)B(Bˉ0→D0ρ0)\frac{{\cal B}(\bar{B}^0_s \to D^0 K^{*0})}{{\cal B}(\bar{B}^0 \to D^0 \rho^0)}

The first observation of the decay $\bar{B}^0_s \to D^0 K^{*0}$ using $pp$ data collected by the LHCb detector at a centre-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 36 pb$^{-1}$, is reported. A signal of $34.4 \pm 6.8$ events is obtained and the absence of signal is rejected with a statistical significance of more than nine standard deviations. The $\bar{B}^0_s \to D^0 K^{*0}$ branching fraction is measured relative to that of $\bar{B}^0 \to D^0 \rho^0$: $\frac{{\cal B}(\bar{B}^0_s \to D^0 K^{*0})}{{\cal B}(\bar{B}^0 \to D^0 \rho^0)} = 1.48 \pm 0.34 \pm 0.15 \pm 0.12$, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the ratio of the $B^0$ and $B^0_s$ hadronisation fractions.Comment: 10 pages, 3 figures, submitted to Phys. Lett. B; ISSN 0370-269

Observation of CP violation in B+ to DK+ decays

An analysis of B+ to DK+ and B+ to Dpi+ decays is presented where the D meson is reconstructed in the two-body final states: K+pi-, K+K-, pi+pi- and pi+K-. Using 1.0 fb-1 of LHCb data, measurements of several observables are made including the first observation of the suppressed mode B+ to DK+, D to pi+K-. CP violation in B+ to DK+ decays is observed with 5.8 sigma significance

Measurement of polarization amplitudes and CP asymmetries in B-0 -> phi K*(892)(0)

An angular analysis of the decay B (0) -> phi K (*)(892)(0) is reported based on a pp collision data sample, corresponding to an integrated luminosity of 1.0 fb(-1), collected at a centre-of-mass energy of root S = 7 TeV with the LHCb detector. The P-wave amplitudes and phases are measured with a greater precision than by previous experiments, and confirm about equal amounts of longitudinal and transverse polarization. The S-wave K+ pi(-) and K+ K- contributions are taken into account and found to be significant. A comparison of the B (0) -> phi K (*)(892)(0) and results shows no evidence for direct CP violation in the rate asymmetry, in the triple-product asymmetries or in the polarization amplitudes and phases

Impacts of wave-current coupling on a mussel cultivation area in an upwelling-driven bay

Poster.-- Oceans Sciences Meeting, 28 February-4 March 2022, , virtual eventBottom boundary layer (BBL) hydrodynamics and its effects on the settling of organic matter were studied during four contrasting seasons in two locations of the upwelling-driven Ría de Vigo (NW Iberia). One site was located in an inner-ria mussel raft area, affected by an intense supply of organic matter due to sinking mussel faeces, and the other was a more external and more wave-exposed site. Shear stress computed based on ADCP currents and wave model results were analysed and compared with ADCP backscatter signal and total mass fluxes recovered by a moored sediment trap. Shear stress in both locations was mainly modulated by the coupling of tidal currents and waves. This wave-current coupling was stronger under downwelling conditions (more frequent during autumn and winter) when southerly waves from the shelf entered into the ria and a negative residual circulation pattern was developed. The resuspension affects not only to aggregates but also the mussel faeces and cohesive sediments. This finding jointly with the fact that dispersion of mussel faeces during sinking was always higher than 30% point to a significant reduction of the particulate material arriving at the seabed. We conclude that these resuspension and dispersion processes mitigate the intense loading of potentially oxidized organic material onto the seafloor sediments, in spite of the lower energetic conditions at the raft site. Our results evidence a large temporal and spatial variability in the BBL energetic conditions along the ria and show how it can affect the final fate of faeces production by mussels. Given the increasing importance of these processes for the ria ecosystem services, BBL dynamics should be considered in the decision-making of mussel raft managementN

Bottom hydrodynamic effects of wave-current coupling on a mussel raft cultivation area

VI Expanding Ocean Frontiers conference (EOF 2021), Barcelona (Spain), 5th - 7th July 2021N

Influence of mussel aquaculture on benthic oxygen fluxes in a coastal upwelling system (Ria de Vigo, NW Iberia)

Oceans Sciences Meeting, 28 February-4 March 2022, virtual eventThe high primary production of the NW Iberian coastal upwelling supports high mussel production in this area. In fact, the Rias Baixas, four coastal embayments located in this region, are the largest mussel producers in Europe. The high mussel filter feeding activity results in a large production of faeces and pseudofaeces that are deposited at the benthic surface. This large loading of mussel biodeposits increases benthic remineralization. However, this type of aquaculture may be affected by climate change. Based on this, the objective of this ongoing study is to quantify the impact of intense mussel aquaculture on benthic remineralization by measuring benthic oxygen fluxes with the non-invasive Aquatic Eddy Covariance (AEC) technique. Two AEC systems were deployed concurrently below a mussel raft and in an adjacent reference location during the upwelling season (June to August, 2021). Benthic oxygen uptake under the mussel raft was approximately two times higher than at the reference location. This result emphasizes the impact mussel aquaculture can have on the oxygen dynamics and carbon cycling. Keywords: Coastal upwelling, Benthic oxygen fluxes, Aquatic Eddy Covariance, Mussel raftN

Benthic O2 Fluxes in a coastal upwelling system ( Ría de Vigo, NW Iberia) measured with the Aquatic Eddy Covariance technique

Poster presented at the Ocean Sciences Meeting 2020, 16-21 February 2020, San Diego, Calif. USAOrganic carbon mineralization and nutrients recycling are critical for the biogeochemical functioning of the coastal regions Benthic O 2 uptake is the most common proxy used to quantify the benthic mineralization rate of organic carbon Glud 2008 The main objective of this study was to determine the magnitude of benthic O 2 fluxes in the Ría de Vigo using the Aquatic Eddy Covariance ( technique (Berg et al 2003 under different hydrodynamic conditions (June and October 2017 and identify the main forcing factors of benthic fluxes in each campaignThis poster is a contribution of the i SMALL project funded by Spanish Ministry of Science and Innovation (CTM 2014 56119 R). M. Amo Seco has been founded by Spanish Government through FPU Formación de Profesorado Unversitario fellowship (FPU18 05051).Peer reviewe