Thin layers of bioluminescent copepods found at density discontinuities in the water column

Widder, Edith A.; Johnsen, Sönke; Bernstein, Stephen A.; Case, James F.; Neilson, Douglas J.

doi:10.1007/s002270050559

Cited by 62 publications

(46 citation statements)

References 39 publications

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“…Generally, the existence of thin vertical layers has been rarely investigated, which is due to the low sampling efficiency of traditional net sampling for marine snow and the generally low ability of this method to resolve small-scale distribution patterns (Widder et al 1999, Alldredge et al 2002, Jacobsen & Norrbin 2009). Studies using optical and acoustical instruments have only recently started to quantitatively describe thin layers of marine snow at density gradients (Alldredge et al 2002, McManus et al 2003.…”

Section: Thin Layers Of Marine Snow and Mesozooplanktonmentioning

confidence: 99%

Marine snow, zooplankton and thin layers: indications of a trophic link from small-scale sampling with the Video Plankton Recorder

Moeller

John²,

Temming

et al. 2012

Mar. Ecol. Prog. Ser.

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Marine aggregates of biogenic origin, known as marine snow, are considered to play a major role in the ocean's particle flux and may represent a concentrated food source for zooplankton. However, observing the marine snow−zooplankton interaction in the field is difficult since conventional net sampling does not collect marine snow quantitatively and cannot resolve so-called thin layers in which this interaction occurs. Hence, field evidence for the importance of the marine snow−zooplankton link is scarce. Here we employed a Video Plankton Recorder (VPR) to quantify small-scale (metres) vertical distribution patterns of fragile marine snow aggregates and zooplankton in the Baltic Sea during late spring 2002. By using this non-invasive optical sampling technique we recorded a peak in copepod abundance (ca. 18 ind. l −1 ) associated with a pronounced thin layer (50 to 55 m) of marine snow (maximum abundance of 28 particles l −1 ), a feature rarely resolved. We provide indirect evidence of copepods feeding on marine snow by computing a spatial overlap index that indicated a strong positively correlated distribution pattern within the thin layer. Furthermore we recorded images of copepods attached to aggregates and demonstrating feeding behaviour, which also suggests a trophic interaction. Our observations highlight the potential significance of marine snow in marine ecosystems and its potential as a food resource for various trophic levels, from bacteria up to fish.

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Section: Thin Layers Of Marine Snow and Mesozooplanktonmentioning

confidence: 99%

Marine snow, zooplankton and thin layers: indications of a trophic link from small-scale sampling with the Video Plankton Recorder

Moeller

John²,

Temming

et al. 2012

Mar. Ecol. Prog. Ser.

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“…These measurements are becoming more prevalent and have now been conducted off ships, on profiling and undulating systems, on moorings, and on autono mous underwater vehicles (AUVs; Widder et al, 1993;Moline et al, 2001Moline et al, , 2005Herren et al, 2005). These efforts have provided new insight into the distribution of coastal bioluminescence at ecosystem scales as it relates to physical forcing and physiological rhythms (Widder et al, 1999;Shulman et al, 2003Shulman et al, , 2005Moline et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Bioluminescence to reveal structure and interaction of coastal planktonic communities

Moline

Blackwell

Case

et al. 2009

Deep Sea Research Part II: Topical Studies in Oceanography

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a b s t r a c tEcosystem function will in large part be determined by functional groups present in biological communities. The simplest distinction with respect to functional groups of an ecosystem is the differentiation between primary and secondary producers. A challenge thus far has been to examine these groups simultaneously with sufficient temporal and spatial resolution for observations to be relevant to the scales of change in coastal oceans. This study takes advantage of general differences in the bioluminescence flash kinetics between planktonic dinoflagellates and zooplankton to measure relative abundances of the two groups within the same-time space volume. This novel approach for distinguishing these general classifications using a single sensor is validated using fluorescence data and exclusion experiments. The approach is then applied to data collected from an autonomous underwater vehicle surveying 4500 km in Monterey Bay and San Luis Obispo Bay, CA during the summers of [2002][2003][2004]. The approach also reveals that identifying trophic interaction between the two planktonic communities may also be possible.

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“…Zooplankton aggregations have been observed near thin layers (high concentration patches in the water column on the order of 1 m thick vertically which can span several square kilometers and last for several days) and other oceanographic structures such as steep velocity and density gradients (Mackas & Louttit 1988, Widder et al 1999, Dekshenieks et al 2001, Holliday et al 2003. The association of peaks in biological activity (primary production and consumers) with these gradients suggests that both physical forcing (patterns created by physical properties) and individual behavioral responses to these physical and biological features play important roles in defining observed in situ patterns of animal distributions (Cowles 2004, Gallager et al 2004, McManus et al 2005.…”

Section: Introductionmentioning

confidence: 99%

Cue hierarchy and foraging in calanoid copepods: ecological implications of oceanographic structure

Woodson¹,

Webster²,

Weissburg³

et al. 2007

Mar. Ecol. Prog. Ser.

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Fine-scale water column structure was mimicked in a laboratory plane jet flume to examine responses of the calanoid copepods Temora longicornis and Acartia tonsa to layers consisting of a velocity gradient, density gradient, phytoplankton exudates and food (phytoplankton). Copepods were exposed to isolated layers and combinations of cues as defined by in situ conditions. Behaviors elicited by the velocity gradient and chemical exudate layers included increased swimming speed and turn frequency consistent with excited area-restricted search behavior, which led to increased proportional residence time in the layers. Both species had significant responses to isolated layers of velocity gradients and chemical exudates, with T. longicornis responding more intensely to chemical cues than velocity gradients and A. tonsa responding equally to both. Combined fluid mechanical and chemical cues elicited species-specific responses. For T. longicornis, chemical presence induced responses that strengthened or cancelled initial reactions to the velocity gradient. These results suggest a cue hierarchy where a velocity gradient acts as an initial cue for narrowing search regions, and chemical cues and food presence determine consequent responses. For A. tonsa, combining velocity gradient and chemical cues had the same effect on copepod behavior as the individual cues, which suggests both cues are equal sources of information but are not closely associated. In both species, physical contact with particles or cells initiated feeding behavior, resulting in lower swimming speeds. Fluid density had a potentially aversive effect, as neither species responded with an area-restricted search response and individuals rarely crossed a strong density gradient. Observed behaviors may lead to aggregation, especially when superimposed on rhythmic movements such as diel vertical migration.

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Thin layers of bioluminescent copepods found at density discontinuities in the water column

Cited by 62 publications

References 39 publications

Marine snow, zooplankton and thin layers: indications of a trophic link from small-scale sampling with the Video Plankton Recorder

Marine snow, zooplankton and thin layers: indications of a trophic link from small-scale sampling with the Video Plankton Recorder

Bioluminescence to reveal structure and interaction of coastal planktonic communities

Cue hierarchy and foraging in calanoid copepods: ecological implications of oceanographic structure

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