We read, with great interest, the article by Lee et al. (1988) concerning the effects of “‘swimmers’” on the measurement of particulate organic matter flux in the marine environment. Generally swimmers are either: (1) acknowledged and their impact reduced by manually removing the carcasses (“picking”) before further sample processing, (2) acknowledged, but trap contents analyzed unaltered, or (3) totally ignored. None of these three options is acceptable, if the desired outcome is to obtain accurate particle flux estimates. As Lee et al. (1988) discuss in their review, the swimmer problem is exacerbated in near-surface waters (≤ 500 m). Unfortunately, the measurement of particulate organic matter flux in the upper water column is crucial to our understanding of biogenic element cycles, including the rates and mechanisms of nutrient regeneration and, consequently, crucial to addressing the Global Ocean Flux Study (GOFS) program objectives (Brewer et al., 1986). Because sediment traps are now recognized as the only method for estimating the passive downward flux of organic matter in the sea (SCOR WG-71 report on “Particulate Biogeochemical Processes,” S. Krishnaswami, chairman), our progress toward a resolution of these important oceanic processes is stalled at this time. So, to provide a brief answer to the rhetorical question posed in their title, “Are ‘Swimmers’ a Problem?,” we believe the reply is an overwhelming affirmative.

Karl, D.M., and G.A. Knauer. 1989. Swimmers: A recapitulation of the problem and a potential solution. Oceanography 2(1):32–35, https://doi.org/10.5670/oceanog.1989.28.

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