“The Fate and Impact of Internal Waves in Nearshore Ecosystems” by C.B. Woodson introduced me to the wonder and science of internal waves. Like the surface waves most people are accustomed to thinking about, these internal waves also break as they near land and can bring of deep offshore waters into the nearshore environment:
These deeper waters are often colder, lower in oxygen, higher in CO2 concentration (lower pH), and nutrient enriched. Consequently, internal waves can dramatically change the ambient environment, leading to either extreme oxygen (hypoxia) or pH (acidification) events. However, they can also mediate extreme heating events by providing a temporary reprieve from high temperatures. Deep offshore waters can also provide nutrients and food subsidies to nearshore ecosystems. Nutrient-deprived nearshore ecosystems, namely coral reefs, can be highly dependent on such subsidies.
Richard Dugdale credits mentoring with influencing his path from electrical engineering to oceanographer in his autobiography “A Biogeochemical Oceanographer at Sea: My Life with Nitrogen and a Nod to Silica” He has a warm writing style and I enjoyed reading about the history of this field through his experiences, especially about the changing technology:
…this field rapidly developed both analytically, starting with the use of stable and radioactive tracers, and computationally, from the use of slide rules to the development of onboard computers with disk drives (with 250 KB of storage!) and the era of smartphones. Also changing has been the mode of communication between oceanographers—from handwritten or mimeographed notes to faxes to the early email and Internet (telemail) used by oceanographers in the 1980s to today’s email and social media. What follows, then, is a biased (biological/chemical) history of a period in which modern oceanography was largely developed and in which I had the great fortune to be a player.
“Spaceborne Lidar in the Study of Marine Systems” by Hostetler et al. is one of several articles in this volume that report on the use of satellites in marine research. This article reviews the use of passive color analysis to observe chlorophyll levels among many other topics and looks forward to an upcoming PACE mission which pairs the color observations with new tools:
Satellite passive ocean color observations have vastly improved our understanding of global links between biodiversity, ecosystem structure, and ecological and biogeochemical function. However, there are fundamental geophysical properties that simply cannot be characterized with ocean color technology alone. Addressing these issues requires additional tools in space. For example, the Plankton, Aerosol, Cloud, and Marine Ecosystem (PACE) mission aims to co-deploy a multi-angle polarimeter with a hyperspectral ocean color sensor, with the polarimetry enabling more accurate atmospheric corrections and advanced characterization of ocean particle types. Here, we describe how even greater synergies may be achieved by combining a passive ocean color sensor with an ocean-optimized satellite profiling lidar.