As climate change drives health declines of tropical reef species, diseases are further eroding ecosystem function and habitat resilience. Coral disease impacts many areas around the world, removing some foundation species to recorded low levels and thwarting worldwide efforts to restore reefs. What we know about coral disease processes remains insufficient to overcome many current challenges in reef conservation, yet cumulative research and management practices are revealing new disease agents (including bacteria, viruses, and eukaryotes), genetic host disease resistance factors, and innovative methods to prevent and mitigate epizootic events (probiotics, antibiotics, and disease resistance breeding programs). The recent outbreak of stony coral tissue loss disease across the Caribbean has reenergized and mobilized the research community to think bigger and do more. This review therefore focuses largely on novel emerging insights into the causes and mechanisms of coral disease and their applications to coral restoration and conservation.
The present-day state and future of the Antarctic Ice Sheet depend on the rate at which the ocean melts its fringing ice shelves. Ocean heat must cross many physical and dynamical barriers to melt ice shelves, with the last of these being the ice-ocean boundary layer. This review summarizes the current understanding of ice-ocean boundary-layer dynamics, focusing on recent progress from laboratory experiments, turbulence-resolving numerical simulations, novel observations, and the application to large-scale simulations. The complex interplay between buoyant meltwater and external processes such as current shear leads to the emergence of several melting regimes that we describe, as well as freezing processes. The remaining challenges include developing new parameterizations for large-scale ice-ocean models based on recent advances and understanding the coevolution of melt and basal topography.
My strategy for writing this autobiography is to use examples of how working on seemingly different projects can often lead to outcomes more important than originally envisioned. Serendipity is a happy accident-specifically, the accident of discovering something useful without directly looking for it. This often occurs when two research projects converge unexpectedly. The main text contains examples of how serendipity has led me to important discoveries, including (a) finding surprisingly high 228Ra activities in the ocean; (b) developing a means of rapidly and quantitatively extracting radium from seawater; (c) devising a rapid, sensitive method of measuring 224Ra and 223Ra; (d) realizing the scale and biogeochemical importance of submarine groundwater discharge; and (e) conceiving a method to estimate the total flux of submarine groundwater discharge to the Atlantic Ocean. The Supplemental Material fleshes out details of these discoveries and places them in the context of my other investigations.
Advancements in space-based ocean observation and computational data processing techniques have demonstrated transformative value for managing living resources, biodiversity, and ecosystems of the ocean. We synthesize advancements in leveraging satellite-derived insights to better understand and manage fishing, an emerging revolution of marine industrialization, ocean hazards, sea surface dynamics, benthic ecosystems, wildlife via electronic tracking, and direct observations of ocean megafauna. We consider how diverse space-based data sources can be better coupled to modernize and improve ocean management. We also highlight examples of how data from space can be developed into tools that can aid marine decision-makers managing subjects from whales to algae. Thoughtful and prospective engagement with such technologies from those inside and outside the marine remote sensing community is, however, essential to ensure that these tools meet their full potential to strengthen the effectiveness of ocean management.
The Earth's oceans have absorbed more than 90% of the excess, climate change-induced atmospheric heat. The resulting rise in oceanic temperatures affects all species and can lead to the collapse of marine ecosystems, including coral reefs. Here, we review the range of methods used to measure thermal stress impacts on reef-building corals, highlighting current standardization practices and necessary refinements to fast-track discoveries and improve interstudy comparisons. We also present technological developments that will undoubtedly enhance our ability to record and analyze standardized data. Although we use corals as an example, the methods described are widely employed in marine sciences, and our recommendations therefore apply to all species and ecosystems. Enhancing collaborative data collection efforts, implementing field-wide standardized protocols, and ensuring data availability through dedicated, openly accessible databases will enable large-scale analysis and monitoring of ecosystem changes, improving our predictive capacities and informing active intervention to mitigate climate change effects on marine life.
According to some authors, the Messinian salinity crisis was ended by a giant waterfall or megaflood 5.33 million years ago, when the Atlantic Ocean reconnected in a catastrophic way with the desiccated Mediterranean, creating the Strait of Gibraltar. An erosional surface deeply cutting upper Miocene or older rocks and sealed by lower Pliocene sediments is the geological feature that inspired this fascinating hypothesis. The hypothesis, which recalls several ancient myths, is well established in the scientific community and often considered to be a fact. However, several studies are suggesting that the Atlantic-Mediterranean connection through the Strait of Gibraltar was probably active before and during the entire Messinian salinity crisis. This allows us to consider the possibility that long-lived, more gradual physical processes were responsible for the evolution of the strait, opening the idea of a nondesiccated Mediterranean Sea.