David Lapota

Observations and measurements of planktonic bioluminescence in and around a milky sea

Abstract The Indian Ocean and Arabian Sea have been observed to exhibit surface bioluminescent displays unparalleled in intensity and spatial extent. In July 1985, we conducted bioluminescence measurements in the surface waters of the western Arabian Sea during the period of the southwest monsoon and to identify the causative plankton for these displays. While an intense stimulable bioluminescence signal was always present (range: 1 − 5 × 10 8 photons per second per cubic centimeter of turbulently flowing seawater, measured by an onboard underway photometer system), a unique type of bioluminescence display, known as “milky sea”, was observed on the ocean surface for 3 days. Luminous dinoflagellates, Zooplankton, and bacteria were isolated and tested in a shipboard laboratory photometer system for bioluminescent potential. Their light output values, together with abundance of luminous species present in collected plankton samples, indicated a stimulable bioluminescence field superimposed on a milky sea. The stimulable bioluminescence field was dominated by luminescent dinoflagellates, primarily Pyrocystis spp. and Protoperidinium spp. The Zooplankton contribution to the overall light budget was estimated at Pleuromamma spp. copepods. Luminous larvaceans, ostracods, siphonophore nectophores, and radiolarians were intermittently present in the samples. First observations of bioluminescence were recorded in the calanoid copepod Pleuromamma quadrungulata (Dahl) and the Calycophorae siphonophores Chelophyes contorta (Lens et Van Riemsdijk), Abylopsis tetragona (Otto), and A. eschscholtzi . Phaeocystis colonies glowed continuously and appeared to act as a substratum for the colonizing luminous bacteria Vibrio harveyi . This bacteria is hypothesized to be the source of the luminescent “milky sea.”

Observations of bioluminescence in marine plankton from the Sea of Cortez

Abstract A bioluminescence chemical oceanography research cruise ( Varifront III ) through the Sea of Cortez from November through December 1981 provided an opportunity to investigate plankton associated with a brilliant and extensive display of surface water bioluminescence at the north end of Ballenas Channel. New observations of bioluminescence were made on larval stages of the euphausiid Nyctiphanes simplex Hansen (Calyptopis II, Furcilia I, II, and III, and juveniles) and Euphausia eximia Hansen (Calyptopis I), the Calanoida copepods Centropages furcatus Dana, Paracalanus indiens Wolfenden, Acrocalanus longicornis Giesbrecht, the Cyclopoida copepods Corycaeus (Corycaeus) speciousus Dana, Corycaeus (Onychocorycaeus) latus Dana, and several dinoflagellates Ceratium breve Ostenfeld and Schmidt, Ceratium horridum Gran, and Ceratium gibberum Gourret. These observations indicate the increasing importance of some of the smaller copepods and larval euphausiids contributing to surface bioluminescence.

Diel Bioluminescence in Heterotrophic and Photosynthetic Marine Dinoflagellates in an Arctic Fjord

Abstract : Oceanic and coastal bioluminescence in surface waters, in many instances, is produced by microscopic dinoflagellates. Their light emission is usually observed at a maximum during the night hours and markedly inhibited during the day. This diel periodicity has never been observed in situ for identified species and never before in heterotrophic Protoperidinium dinoflagellates. Pronounced differences in stimulable bioluminescence measured with bathyphotometers in Vestfjord, Norway in September 1990 correlated with simultaneous ship-board laboratory experiments. Cells of both the photosynthetic Ceratium fusus and heterotrophic Protoperidinium curtipes showed a pronounced inhibition of bioluminescence during the day and maximum bioluminescence at night.

Bioluminescence: spatial statistics in the North Atlantic

Abstract Surface bioluminescence, temperature, and chlorophyll fluorescence data for a North Atlantic transect (Copenhagen, Denmark to Wilmington, NC) were analysed statistically. Bioluminescence standard deviations were highly correlated with mean levels ( r = 0.93, P « 0.01 ); the standard deviation to mean ratio was approximately 0.5. The gamma probability distribution function (pd) with k = 4, which has a standard deviation to mean ratio of 0.5, gave a reasonable fit to the bioluminescence pds. Spectral analysis of bioluminescence data showed ocean structure (fronts, eddies, upwelling, etc.) in nearshore and North Atlantic Current waters at spatial scales >2−3 km. Structure generally was not observed at scales r = 0.67, P r = 0.76, P r = 0.98 for region averages) and with this ratio cubed ( r = 0.78, P