Richard W. Eppley's Contributions to Phytoplankton Physiology and Biological Oceanography

Abstract

Richard 14,: Epplev has established himself as one ~f ttte most iJ!fluential biological oceanographers of this century through his contributions to the fieM of phytoplankton physiological ecology and his interdisciplinary approach to oceanographic processes. Dick's ability to generalize and conceptualize, to take separate threads of research and weave them into a cohesive fi'amework, has enabled hint to use established techniques in novel appli~'ations, to define new approaches to old oceanographic questions, and to chart new paths. The nature attd quality of his work, and particularly the breadth c~'his interest and e.wertise, places hint with H.H. Gran, G.A. Riley, J.D.H. Strickland, and others who have given the field ef biological oceanography its conceptual structure. Dick's retirement in December 1989, after thirty-m'o years ~?/ progressional service to the oceanographic community, provides an opportlmi(v to reflect on his various accomplishments. In this article, his./briner Ph.D. students and postdoctoral associates briefly (and incompletely) review his contributions to oceanographic research attd the oceanographic community. While Dick built on the work ~?f earlier researchers and matt 3' others ~ 'ere cono'ibuthlg to the same topics that Di~ "k was studyhtg, due to .wace ~'onstraints only those papers authored by Dick are cited. Because Dick always strove to place his work in historical cmztext, the papers referred to below provide a key to the groundbreaking work by othepw.

SN 2001em: NOT SO FAST

“…Preliminary models of VLA observations suggest an average mass-loss of ∼ 2.5 × 10 −4 M ⊙ year −1 , assuming wind-driven, clumpy/filamentary CSM Stockdale et al 2007). Weiler et al (2002) indicates that such a radio-derived mass-loss rate is slightly higher than values determined for other type IIn SNe, 1.14×10 −4 M ⊙ year −1 for SN 1988Z and 4.28×10 −5 M ⊙ year −1 for SN 1986J. However, depending on when this shell of material was ejected, the actual mass-loss event was likely much higher than this average value.…”

Subsurface Chlorophyll Maximum Layers: Enduring Enigma or Mystery Solved?

“…Instead, these subsurface Chl maxima generally represent ecologically significant features of the planktonic ecosystemcontiguous layers of phytoplankton that are nearly ubiquitous in stratified waters and that have attracted focused examination since benchmark modeling studies by Gordon Riley and John Steele (Riley et al 1949;Steele 1956Steele , 1964Steele & Yentsch 1960) and some of the first continuous vertical profiles of chlorophyll fluorescence that revealed previously unappreciated features in the vertical distributions of phytoplankton (Strickland 1968). My studies of subsurface chlorophyll maximum layers (SCMLs) began nearly 40 years ago under the supervision of Richard W. Eppley, one of the most influential biological oceanographers of the twentieth century (Weiler et al 1990). His guidance on how to approach this scientific problem is as appropriate now as it was then.…”

Limnology and Oceanography Bulletin Volume 33 Number 1 February 2024 1‐43

“…Seeking better opportunities for his growing family after teaching at the University of Southern California (1957California ( -1960, he took a research position with the Northrop Corporation (1960)(1961)(1962)(1963) where he worked on culturing algae for life support in space vehicles. In a tribute published shortly after his retirement in 1989 (Weiler et al 1990), Dick Eppley's eight Ph.D. students and four postdoctoral researchers (Table 2) reviewed his important contributions to pursuits that had become central to modern biological oceanography at the time. These included: The 1990 article describing Eppley's research provides a roadmap to a trove of information on his publications and their impacts at that time.…”

“…Recognizing the breadth, depth, and insight of his research, Dick's students and postdocs concluded that "Richard W. Eppley has established himself as one of the most influential biological oceanographers of this century through his contributions to the field of phytoplankton physiological ecology and his interdisciplinary approach to oceanographic processes" (Weiler et al 1990). As illustrated with a few examples of key papers in Table 1, Dick's work has continued to influence the direction of oceanographic research well into the 21 st century and it is clearly foundational for studies of phytoplankton dynamics and biogeochemical cycles.…”

“…As explained by Weiler et al (1990) in much more detail, over decades Dick studied the influences of light, nutrients, and temperature on the relationships between growth rate, photosynthetic rate per weight of chlorophyll, and the carbon : chlorophyll ratio in phytoplankton. He knew that this was the most direct way to describe and explain the distributions and activities of marine phytoplankton based on the measurements available at the time: chlorophyll a, 14 C-primary productivity, particulate organic carbon and nitrogen, and conventionally measured nutrient concentrations.…”