Our study focuses on the characteristics of MHWs in the Red Sea during the last 4 decades. Using satellite-derived sea surface temperatures (SSTs), we found a clear warming trend in the Red Sea since 1994, which has intensified significantly since 2016. This SST rise was associated with an increase in the frequency and days of MHWs. In addition, a correlation was found between the frequency of MHWs and some climate modes, which was more pronounced in some years of the study period.

This paper presents the results of the first scientific campaign of a new method to remotely sense the small-scale, fast-evolving dynamics that are vital to our understanding of coastal and shelf sea processes. This work represents the first demonstration of the simultaneous measurement of current and wind vectors from this novel method. Comparisons with other current measuring systems and models around the dynamic area of the Iroise Sea are presented and show excellent agreement.

This study advances the understanding of climate projection variability in the Nemunas River, Curonian Lagoon, and southeastern Baltic Sea continuum by analyzing a subset of climate models with a focus on a coupled ocean and drainage basin model. This study investigates the variability and trends in environmental parameters, such as water fluxes, timing, nutrient load, water temperature, ice cover, and saltwater intrusions in Representative Concentration Pathway 4.5 and 8.5 scenarios.

The biological carbon pump plays a key role in the climate system. Plankton absorb and transform CO₂ into organic carbon, forming particles that sink to the ocean floor. Sediment traps catch these particles and measure the carbon stored in the abyss. However, the particles' surface origin is unknown as ocean currents alter their paths. Here, we train an AI model to predict the origin of these particles. This new tool enables a better link between deep-ocean observations and satellite images.

Using a high-resolution model, we estimated the volume, freshwater, and heat transports along Indian coasts. Affected by coastal currents, transport along the eastern coast is highly seasonal, and the western coast is impacted by intraseasonal oscillations. Coastal currents and equatorial forcing determine the relation between NHT and net heat flux in dissipating heat in coastal waters. The north Indian Ocean functions as a heat source or sink based on seasonal flow of meridional heat transport.

This study examines the seasonal variability in internal tide sea surface height in a global model simulation. We also compare this with altimetry and the seasonal variability in the internal tide energy terms. Georges Bank and the Arabian Sea show the strongest seasonal variability. This study also reveals that sea surface height may not be the most accurate indicator of the true seasonal variability in the internal tides because it is modulated by the seasonal variability in stratification.

We used a simplified model to investigate how changes in abyssal stratification can impact the propagation of vortices in the ocean. Although abyssal stratification is typically considered stable, observations have shown that this is not always a good approximation. We found that changes in deep stratification can introduce variability into the patterns of the vortices. Despite the assumptions made in our model, our results are supported by seafloor observations in the Ionian Sea.

We studied the increasing or decreasing of chlorophyll a abundance in the German Bight. Chlorophyll a is the pigment present in algae that allows them to capture energy from the sun and indicates both the growth of the algae and the health of the environment. Most of the German Bight has decreasing chlorophyll a concentration in the analysed period. In addition, about 45 % of the changes happening in chlorophyll a were connected with changes in temperature.

In the Weddell Sea, we investigated how warm deep currents and cold waters containing freshwater released from the Antarctic are connected. We used autonomous observation devices that have never been used in this region previously and that allow us to track the movement and characteristics of water masses under the sea ice. Our findings show a dynamic interaction between warm masses, providing key insights to understand climate-related changes in the region.

The latitudinally alternating zonal jets are a ubiquitous feature of the ocean. We use a simple model to illustrate the potential role of these jets in the formation, maintenance, and multidecadal variability in the oxygen minimum zones, using the eastern tropical North Atlantic oxygen minimum zone as an example.

Eastern boundary upwelling systems (EBUSs) are crucial for resources, but climate change poses uncertainties for their future. To assess global warming's impact, we examine Andrew Bakun's 1990 hypothesis of intensified upwelling using deseasonalized sea surface temperature data. A new index, α_UI, normalizes upwelling trends against non-upwelling processes, confirming intensification in all EBUSs and supporting Bakun's hypothesis.

An AI model was used to fill in missing parts of sea temperature (SST) maps caused by cloud cover. We found masked autoencoders can recreate missing SSTs with less than 0.2 °C error, even when 80 % are missing. This is 5000 times faster than conventional methods tested on a single central processing unit. This can enhance our ability in monitoring global small-scale ocean fronts that affect heat, carbon, and nutrient exchange in the ocean. The method is promising for future research.

The ocean takes up carbon dioxide (CO₂) from the atmosphere, slowing climate change. This CO₂ uptake is controlled by a property called ƒCO₂. Seawater ƒCO₂ changes as seawater warms or cools, although by an uncertain amount; measurements and calculations give inconsistent results. Here, we work out how ƒCO₂ should, in theory, respond to temperature. This matches field data and model calculations but still has discrepancies with scarce laboratory results, which need more measurements to resolve.

This study examines how the ocean's chaotic variability and atmospheric fluctuations affect yearly changes in North Atlantic Subtropical Mode Water (STMW) properties, using an ensemble of realistic ocean simulations. Results show that while yearly changes in STMW properties are mostly paced by the atmosphere, a notable part of these changes are random in phase. This study also illustrates the value of ensemble simulations over single runs in understanding oceanic fluctuations and their causes.

Around 90 % global warming occurs in the ocean but is insufficiently understood at the air–sea interface. Thermodynamics of the standard TEOS-10 is an improved tool for the description of heat exchange processes.

Here, we describe several sea trials with the newly developed CO₂ Seaglider in the Gulf of Alaska. Data evaluation with discrete water and underway samples suggests nearly "weather-quality" CO₂ data as defined by the Global Ocean Acidification Network.

We present an observational study investigating total alkalinity (TA) in the Dutch Wadden Sea. Discrete water samples were used to identify the TA spatial distribution patterns and locate and shed light on TA sources. By observing a tidal cycle, the sediments and pore water exchange were identified as local TA sources. We assumed metabolically driven CaCO₃ dissolution as the TA source in the upper, oxic sediments and anaerobic metabolic processes as TA sources in the deeper, anoxic ones.