Temporal variability in the vertical structure of bioluminescence in the North Atlantic Ocean

Abstract

The temporal and depth variability of stimulated bioluminescence at 59øN, 21øW in the North Atlantic during 1991 was measured by two bathyphotometers (BP's). A moored BP (MOORDEX) obtained a 106-day time series of bioluminescence at 50 m between May 1 and August 15. A profiling BP (high-intake, defined excitation, HIDEX) measured bioluminescence in the upper water column during cruises in May and August. MOORDEX-measured bioluminescence intensity cycled with an approximate 20-day periodicity. In May, bioluminescence was correlated with chlorophyll fluorescence with similar vertical distributions in the water column. From May to August, the mean intensity and duration of individual flash events increased, and integrated water column bioluminescence increased by a factor of 4, to 1.2 x 1015 quantam -2. In August, chlorophyll fluorescence distributions and mixed layer depths were shallower than in May. Despite this, the vertical distribution of bioluminescence remained unchanged from May. The following results, potentially caused by typical seasonal changes superimposed upon short-term high variability during each cruise, suggest a change in organism assemblage between May and August: (1) increase in the intensity of flash events, (2) shift to a broader distribution of flash kinetics, and (3) loss of correlation between fluorescence and bioluminescence. Introduction The dynamics of biological communities in the ocean are driven by physical, optical, and chemical processes, with changes in biological communities correlated with temporal and spatial variability in these bulk processes. For example, the spring bloom phenomenon in the North Atlantic is correlated with increased solar insolation and shallowing of the mixed layer [Ducklow and Harris, 1993]. Bioluminescence is a ubiquitous feature of the world's oceans and originates from organisms representing all trophic levels. Because background levels of in situ bioluminescence are low [Baguet et al., 1983; Widder et al., 1989], profiling, moored, and ship-mounted bathyphotometers [e.g., Losee et al., 1985; Swift et al., 1985; Ondercin, 1989; Widder et al., 1993] are used to measure levels of stimulated bioluminescence in situ. Although on scales larger than 100 km, bioluminescence may be correlated with hydrographic features [e.g., Swift et al., 1985; Losee et al., 1989], on smaller scales there are few correlations of bioluminescence with other bulk properties [e.g., Ondercin, 1989]. Bioluminescence has been correlated with beam attenuation [Lapota et al., 1989], the chlorophyll to temperature ratio [Losee et al., 1989], and zooplankton biomass [Buskey, 1992].

Long Term Dinoflagellate Bioluminescence, Chlorophyll, and Their Environmental Correlates in Southern California Coastal Waters

“…This strengthens the inference that the physical environment in the bight is fairly stable with respect to seasonality, and that bioluminescence is strongly influenced by seasonal rainfall and runoff. Southern California Bight bioluminescence is similar to that found in coastal waters of Vestfjord, Norway (Lapota 1990, unpublished), and the Arabian Sea (Lapota & Rosenberger 1990), but higher than that found in the Sargasso Sea (Batchelder & Swift 1989), the North Atlantic (Neilson et al 1995) and the Beaufort Sea (Lapota et al 1992). The vertical structure of bioluminescence was correlated with Chl fluorescence for some of the stations in the Bight.…”

“…While many oceanographic studies have focused on the distribution of bioluminescence in the marine environment (Stukalin 1934, Tarasov 1956, Seliger et al 1961, Clarke and Kelly 1965, Bityukov 1967, Lapota and Losee 1984, Swift et al 1985, Lapota et al 1988, Batchelder and Swift 1989, Lapota et al 1989, Lapota and Rosenberger 1990, Neilson et al 1995, Ondercin et al 1995, Swift et al 1995, little understanding of the seasonality and sources of planktonic bioluminescence in coastal waters and open ocean has emerged. Some previous studies with respect to annual cycles of bioluminescence were severely limited in duration as well as in the methods used to quantify bioluminescence (Bityukov 1967, Tett 1971.…”

Long Term Dinoflagellate Bioluminescence, Chlorophyll, And Their Environmental Correlates In Southern California Coastal Waters

“…While many oceanographic studies have focused on the distribution of bioluminescence in the marine environment (Stukalin 1934, Tarasov 1956, Seliger et al 1961, Clarke and Kelly 1965, Bityukov 1967, Lapota and Losee 1984, Swift et al 1985, Lapota et al 1988, Batchelder and Swift 1989, Lapota et al 1989, Lapota and Rosenberger 1990, Neilson et al 1995, Ondercin et al 1995, Swift et al 1995, little understanding of the seasonality and sources of planktonic bioluminescence in coastal waters and open ocean has emerged. Some previous studies with respect to annual cycles of bioluminescence were severely limited in duration as well as in the methods used to quantify bioluminescence (Bityukov 1967, Tett 1971.…”

A multi-platform bathyphotometer for fine-scale, coastal bioluminescence research

“…Bathyphotometers have provided information about bioluminescent organisms, specifically the spatial and temporal location of BL as well as its relationship with other measured biological, physical, and chemical parameters in the ocean (e.g., Neilson et al 1995;Widder et al 1999;McManus et al 2003). Using a BP, Swift et al (1983) and Batchelder and Swift (1989) showed that zooplankton were usually major sources of epipelagic BL in the southern Sargasso Sea, except when the concentration of the BL dinoflagellate Pyrocystis noctiluca was high.…”

“…Bathyphotometers with high flow rates (18 L s -1 and higher), such as HIDEX (Widder et al 1993;Neilson et al 1995), were initially designed to ensure optimal capture efficiency in the open ocean where bioluminescent organisms vary widely in abundance and ability to avoid capture. In coastal waters, such high flow rates and large instruments might obscure the fine-scale distribution of bioluminescent organisms, and make it difficult to discriminate individual organisms amidst the bulk BL signal.…”