Ash from the Calbuco 2015 eruption spread across northern Patagonia, the SE Pacific and SW Atlantic Oceans. In the Pacific, a phytoplankton bloom corresponded closely to the volcanic ash plume, suggesting that ash fertilized this region of the ocean. No such fertilization was found in the Atlantic where nutrients plaussibly supplied by ash were likely already in excess of phytoplankton demand. In Patagonia, the May bloom was more intense than usual, but the mechanistic link to ash less clear.

Coastal trapped waves (CTWs) are very long shallow water waves that propagate along the continental shelves of most major ocean basins. Their general properties are known but can be easily modified by changes in the coastline or other factors through a process known as scattering. Scattering is not well understood but can cause high surface velocities. For the first time, we directly observe CTW scattering using a simple mathematical technique that can be easily applied to other coastlines.

This article accounted for the change in sediment supply in the central Yellow Sea since the Last glacial maximum. Sediment sources were distinguished based on the integration of clay mineralogical and geochemical data such as trace elements and Sr/Nd isotopes. The core PCL14 was divided into four units and showed clear vertical variations according to sediment supply and sea-level change.

The Atlantic Meridional Overturning Circulation (AMOC) is an important component of the climate system. Understanding its structure and variability is a key priority for many scientists. Here, we present the first estimate of AMOC variations for the tropical South Atlantic – from the TRACOS array at 11° S. Over the observed period, the AMOC is dominated by seasonal variability. We investigate the respective mechanisms with an ocean model and find different wind-forced waves to play a big role.

Internal tides can have a signature of several cm at the ocean surface and need to be corrected from altimeter measurements. This paper presents a detailed validation of several internal tides models using existing satellite altimeter databases. The analysis focuses on the main diurnal and semi-diurnal tidal constituents. Results show the interest of the methodology proposed, the quality of the internal tide models tested and their positive contribution for estimating an accurate sea level.

Diel vertical migration (DVM) of zooplankton is the largest non-human migration on the Earth. DVM in the eastern Beaufort Sea was assessed using a two-year-long time series of currents and acoustic signal from the bottom-anchored oceanographic mooring. Our results show that DVM is deviated by the (i) seasonal and inter-annual variability in sea-ice and (ii) wind-driven water dynamics. We also observed the midnight sun DVM during summer 2004, a signal masked by suspended particles in summer 2005.

The ocean is a turbulent system, full of meandering currents and fronts of various scales. These processes can influence the distribution of microscopic algae or phytoplankton by upwelling deep, nutrient-rich waters to the sunlit surface or by actively gathering and accumulating them. Our results suggest that at surface, salinity is the main conditioning factor for phytoplankton distribution. However, at the subsurface, oceanic currents influence the phytoplankton distribution the most.

We investigated the long-term changes of the principal tidal component M₂ over the North Atlantic coasts, from 1846 to 2018. We analysed 9 tide gauges. We found that M₂ variations are consistent at all the stations in the North East Atlantic, whereas some discrepancies appear in the North West Atlantic. The similarity between the North Atlantic Oscillation and M₂ variations in the North East Atlantic suggests a possible influence of the large-scale atmospheric circulation on the tide.

A large percentage of global ocean plastic enters the Indian Ocean through rivers but the fate of these plastics is generally unknown. In this paper, we use computer simulations to show that floating plastics “beach” and end up on coastlines throughout the Indian Ocean. Coastlines where a lot of plastic enters the ocean are heavily affected by beaching plastic, but plastics can also beach far from the source on remote islands and countries that contribute little plastic pollution of their own.

The coastal East China Sea (ECS) is a highly productive system characterized of multiple spatial and temporal scale, in which physical, biogeochemical and ecological processes strongly interact. A coupled model system was implemented to a high resolution coastal ECS. The model was capable to reproduce main temporal and spatial features for phytoplankton and nutrients. This work could form a significant basis for future work, e.g. the response of biogeochemical flux to physical mechanism.

From the global escape of light gases (H, ammonia, water vapour) to space, the global water loss could not be estimated. Therefore the ancient and recent sea levels and volumes were used to estimate the disappearance of water from the Earth. Earlier high sea levels with decreasing fluctuations indicate water loss long before man existed. Highest sea level was referred to as the Infant Sea with an estimated volume that could have been by 26 % more voluminous than it is today.

The proposed method of data assimilation is capable of effectively correcting basin-scale mismatch of oceanographic model when the domain is under nearly coherent external forcing. The method uses basin scale EOF modes, calculated from the long-term model statistics. These modes are used to reconstruct gridded fields from point observations, which are further fed to the model using relaxation. Tests with sea surface temperature and salinity in the NE Baltic Sea were successful.

The South China Sea is characterized by abundant phytoplankton and energetic internal waves. The distribution of turbulent mixing is uneven in the South China Sea. It is not clear how turbulent mixing affects the distribution of nutrients and chlorophyll in the South China Sea. Investigating the impact of turbulent mixing on the distributions of nutrient and chlorophyll is important to understand the bio-dynamic process and improve the marine ecological model in the South China Sea.

Ekman's (1905) solution for how wind affects ocean surface currents is revisited and extended analytically for a piecewise-constant profile of vertical diffusion. This allows a comprehensive understanding of how the surface current deflection angle relative to the wind direction varies with the profile of vertical diffusion.

Because the density of seawater depends on both temperature (T) and salinity (S), it is possible for seawater samples of the same density to have possibly widely different T/S characteristics, ranging from hot and salt (spicy) to fresh and cold (minty). For several decades, oceanographers have been debating about how best to construct a variable for quantifying the spiciness of seawater. This work discusses the relative merits/drawbacks of existing approaches and proposes a new way forward.

The mixing of water masses into the deep ocean in the North Atlantic is important for the entire global ocean circulation. We use seven global climate models to investigate the effect of increasing the model resolution on this deep ocean mixing. The main result is that increased model resolution leads to a deeper mixing of water masses in the Labrador Sea but has less effect in the Greenland Sea. However, most of the models overestimate the deep ocean mixing compared to observations.

This paper proposes a new algorithm called AFTER-SSIM algorithm to evaluate the performance of 101 selected global climate models under different emission scenarios during 2006 to 2018 and reduces the uncertainty among them.  AFTER-SSIM algorithm shows good performance in sea ice combined forecast and uncertainty reduction among global climate models. The possibility beyond 80 % indicates that the Arctic Northern Sea Route will be open to 1A super vessels for 5 months in the year of 2030.

The Earth System Models in the CMIP5 are widely used to study climate change, so the accuracy of models should be evaluated in key areas such as the North Atlantic where the relationship between the winter sea surface temperature (SST) and the North Atlantic Oscillation (NAO) is very important. Our results show that the link between the SST and the NAO-driven turbulent heat fluxes cannot be well simulated by most models, leading to that models cannot reproduce the observed NAO–SST relationship.