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This editorial, published in Frontiers in Marine Science, emphasizes the importance of using high-resolution observation methods to better understand the effects and mechanisms of coastal eutrophication, deoxygenation, and acidification. The coastal ocean is facing environmental challenges due to climate change and human activities, and traditional sampling methods are insufficient to fully comprehend these issues. The editorial highlights several studies that employ high-resolution methods to investigate topics such as submarine groundwater discharge, terrigenous particle transportation, seasonal oxygen depletion, and the driving forces behind ocean acidification. These studies offer valuable insights into the impacts of these environmental problems and contribute to our understanding of coastal ecosystems. It is important to note that the claims made in this article are those of the authors and do not necessarily reflect the views of their affiliated organizations or the publisher. Additionally, the publisher does not guarantee or endorse any products or claims made by manufacturers. This article is particularly relevant to library patrons conducting research in the field of marine science. [Extracted from the article]

Questions of whether diurnal changes in carbon fixation affect the global carbon budget cannot be answered using the present generation of polar orbiting ocean color sensors that can only retrieve one image daily. Here, we present novel satellite‐derived indices of chlorophyll‐based production based on the Geostationary Ocean Color Imager (GOCI), whose hourly imaging capability offer the potential for direct estimates of net phytoplankton growth over hourly to seasonal time scales. Our results reveal large variations in net chlorophyll growth in the GOCI study region, both over the day and between seasons. Hourly changes in chlorophyll concentration are highest during spring while growth rates show maxima during the winter. We show seasonal relationships between growth and photon flux. Our study suggests that Geostationary Ocean Color data can be used to constrain phytoplankton productivity on diurnal time scales and be an essential tool to better understand diurnal growth patterns over large spatial regions. Plain Language Summary: The rate at which microscopic ocean plants, or phytoplankton, consume carbon dioxide represents a gap in scientific knowledge that needs to be filled in order to better model the earth system. To aid in this understanding we use a novel technique that allows us to track the growth behavior of phytoplankton in the Yellow Sea and the East Sea‐Japan Sea. This is enabled by using satellite data from the Geostationary Ocean Color Imager, which has the unprecedented ability to collect quality biological information from the ocean surface each daylight hour. We find that the results, while in agreement with local observations and other satellite studies, also contain information about how phytoplankton change over daily to annual cycles and how native communities adapt in response to the annual solar cycle. This information is useful to the ocean modeling community, that seeks to understand various ways in which phytoplankton communities affect the cycling of Earth's carbon. Key Points: The Geostationary Ocean Color Instrument tracks changes in net phytoplankton growth at hourly intervalsGains, losses, and net accumulations of chlorophyll show strong diurnal and seasonal variabilitySeasonality in net growth versus light provides evidence for seasonal evolution in phytoplankton community composition [ABSTRACT FROM AUTHOR]

The partial pressure of carbon dioxide (pCO2) was surveyed across the Amazon River plume and the surrounding western tropical North Atlantic Ocean (15–0°N, 43–60°W) during three oceanic expeditions (May–June 2010, September–October 2011, and July 2012). The survey timing was chosen according to previously described temporal variability in plume behavior due to changing river discharge and winds. In situ sea surface pCO2 and air‐sea CO2 flux exhibited robust linear relationships with sea surface salinity (SSS; 15 < SSS < 35), although the relationships differed among the surveys. Regional distributions of pCO2 and CO2 flux were estimated using SSS maps from high‐resolution ocean color satellite‐derived (MODIS‐Aqua) diffuse attenuation coefficient at 490 nm (Kd490) during the periods of study. Results confirmed that the plume is a net CO2 sink with distinctive temporal variability: the strongest drawdown occurred during the spring flood (−2.39 ± 1.29 mmol m−2 d−1 in June 2010), while moderate drawdown with relatively greater spatial variability was observed during the transitional stages of declining river discharge (−0.42 ± 0.76 mmol m−2 d−1 in September–October 2011). The region turned into a weak source in July 2012 (0.26 ± 0.62 mmol m−2 d−1) when strong CO2 uptake in the mid‐plume was overwhelmed by weak CO2 outgassing over a larger area in the outer plume. Outgassing near the mouth of the river was observed in July 2012. Our observations draw attention to the importance of assessing the variable impacts of biological activity, export, and air‐sea gas exchange before estimating regional CO2 fluxes from salinity distributions alone. Plain Language Summary: The Amazon River is the world's largest river with a watershed covering ∼3 million square miles. Its delivery of massive amounts of freshwater, organic material, and nutrients to the salty ocean produces an extensive 30–50 feet thick layer of fresher seawater, called the "plume", floating on the surface of the tropical Atlantic. This plume is spread by winds and currents to cover an additional ∼1 million square miles of the "river‐ocean continuum". We studied how this plume impacts the air‐sea exchange of the greenhouse gas, carbon dioxide (CO2). We combined shipboard measurements with satellite data to estimate the full regional impact (beyond what we could observe from the ship) and examined temporal variation in this exchange. We observed rapid atmospheric CO2 uptake by the plume in regions dominated by algal blooms. We also observed a large CO2 release from the plume near the river mouth, likely due to microbial community respiration of riverine material. Differences in the size and salinity distribution of the plume can greatly modify the plume's impact on CO2 exchange. Our observations draw attention to understanding these variable mechanisms before using the plume extent alone to estimate future impacts on carbon uptake by this key ocean region. Key Points: The Amazon River plume is a net sink for atmospheric CO2Plume size and salinity distribution affect the magnitude of the regional sinkTemporal variations in the relationship between salinity and CO2 flux occur due to changing wind speed, biological activity, and export [ABSTRACT FROM AUTHOR]