FAU Institutional Repository http://purl.fcla.edu/fau/fauir This paper was submitted by the faculty of FAU’s Harbor Branch Oceanographic Institute. Notice: ©1994 Oxford University Press. This is an electronic version of an article published in Journal of Plankton Research, http://plankt.oxfordjournals.org/, and may be cited as: Bailey, T. G., Youngbluth, M. J., & Owen, G. P. (1994). Chemical composition and oxygen consumption rates of ctenophore Bolinopsis infundibulum from the Gulf of Maine. Journal of Plankton Research, 16(6), 673- 689. doi:10.1093/plankt/16.6.673 ~ "\J~ Journal of Plankton Research Vol. 16 no.6 pp.673-6g9. 199.+ \ Chemical composition and oxygen consumption rates of the ctenophore Bolinopsis infundibulum from the Gulf of Maine TG.Bailey, M.J.Youngbluth and G.P.Owen Harbor Branch Oceanographic Institution, 5600 U.S. I North, Fort Pierce, FL 34946, USA Abstract. Quantitative determinations of chemical composition and oxygen consumption rates were made for a deep-living population of the lobate ctenophore Bolinopsis infundibulum. Animals were collected in the Gulf of Maine with the submersible 'Johnson-Sea-Link' during September 1999 at depths ranging from 120 to 240 m. Carbon and nitrogen contents were similar to values reported for cpipelagic ctenophores. Lipid and protein levels were lower than values typical of epipelagic ctenophores, hut higher than those of mesopelagic species. Carbohydrate was nearly an order of magnitude higher than previously recorded for B.infundihulum. Oxygen consumption rates ranged from 0.004 to 0.215 u.l 0, mg -I dry weight h-I at temperatures ranging from 5 to 7°C. Carbon­ specific metabolic rates ranged from 0.21 to 12.n f.ll 0, mg - I C h- I. Energy expenditures estimated from respiration data (~3')(, hody C day-I) indicated that up to 350 small copepods (e.g. Pseudocalanus sp.) or 23 larger copepods (e.g. Calanus jinmarchicusi would be necessary to provide the daily maintenance ration required by a 92 mm B.inflmdihulum. These metabolic characteristics suggest that B.infundibulum could have a significant impact on prey populations in the Gulf of Maine. Introduction Midwater environments of the ocean have become a focus for research over the past decade, principally because water column processes at midwater depths may significantly influence the cycling of biogenic materials between the surface ocean and the deep sea. A particularly important biological finding has been the discovery that many gelatinous zooplankton are widespread and often abundant at mesopelagic depths (Wiebe et al., 1979; Alldredge, 1984; Youngbluth et al., 1990). The broad spectrum of living and detrital particles consumed by these animals qualify salps, appendicularians, ctenophores, siphonophores and medusae as undoubtedly important regulators of biogeochemical flux (Alldredge, 1984). The ubiquitous distribution of gelatinous zooplankton and their periodic numerical dominance in oceanic communities suggest that their metabolic activities, at times, represent a significant fraction of the total macrozooplankton energy budget. Furthermore, many gelatinous species (e.g. ctenophores, siphonophores and medusae) are predators of smaller zooplankton and larval fishes and, when abundant, can have major impacts on prey populations (Fraser, 1962; Larson, 1987; Mackie et al., 1987). Indeed, in the Gulf of Maine, ctenophores, along with other gelatinous species (e.g. medusae and siphonophores), are among the major predators of small planktonic crustaceans, fish eggs and larval fishes (Rogers et al., 1978; Davis, 1984). Bolinopsis infundibulum is a boreal-Arctic lobate ctenophore which inhabits coastal waters from New England to Labrador in the northwestern Atlantic, across the Arctic Seas, and along Scotland and Norway in the eastern Atlantic and into the Baltic (Bigelow, 1926; Zelickrnan, 1972; Lenz, 1973). Although © Oxford University Press 673 T.G.Bailey, M.J.Youngblutb and G.P.Owen often reported as a surface dweller, B. infundibulum is generally found in deeper water (Morris et al., 1993). In the Gulf of Maine, this species is most numerous in the uppermost 100 m from July until September (Bigelow, 1926). Seasonality in the abundance of deeper-living populations is unknown (Gamble, 1977; Morris et al., 1993). Investigations of Biinjundibulum collected from surface waters indicate that this species is a voracious, opportunistic predator of small copepods (e .g. Acartia, Temora, Pseudocalanus, Centropages and Calanus copepodite stages IV and V) and cladocerans (Podon and Evadne) (Nagabhus­ hanam, 1959; Kamshilov, 1960; Anderson, 1974; Gamble, 1974, 1977). Because Biinfundibulum is an extremely delicate planktonic animal (Bigelow, 1926; Greve, 1970; Lenz, 1973; Gamble, 1974, 1977; Reeve and Walter, 1978; Morris et al., 1993), information regarding its biology is scarce. What little biological data that are available for Biinfundibulum have been derived from studies of epipelagic specimens. Most of these investigations have focused on feeding, techniques for laboratory maintenance, chemical composition and fecundity (Nagabhushanarn, 1959; Kamshilov, 1960; Greve, 1970; Gamble, 1974,1977; Reeve and Walter, 1979; Hoeger, 1993; Morris et al., 1983; Schulze­ Robbecke, 1994; Andrew et al., 1987). No quantitative data have been published on the ecology or physiology of deeper-living populations. The only data on metabolic rates for B.infundibulum were taken from eight small specimens collected with a net at the surface off Helgoland, FRG (Gyllenhurg and Greve, 1979). This paper presents the first quantitative assessments of the chemical composition and rates of oxygen consumption for Biinfundibulum from deep­ living populations. Minimum daily rations derived from these data provided estimates of the predatory role of this species. Method Individual B. infundibulum were collected in the Gulf of Maine (Wilkinson Basin; 42°20'N, 69°4TW) from the 'Johnson-Sea-Link' submersible during September 1999, at depths ranging from 120 to 240 m (Table I). Temperature, salinity and oxygen recorded at the sampling depths varied from 5.0 to 6.3°C, 32.6 to 33.0%0 and 10.7 to 11.9 mg O 2 r', respectively (Table I; Figure 1). Metabolic rates were measured in a shipboard environmental room at in situ temperatures (6.0 ± 1.0°C). An array of four specially designed 6.5-1 respirometers attached to the submersible were used to gently trap the ctenophores (Youngbluth, 1994). The 1.25-cm-thick acrylic samplers provided sufficient insulation to maintain in situ temperatures within the samplers during ascent to the surface and during the 10-15 min period required after recovery to transfer them to the environmental room aboard ship. On each of four dives, two or three ctenophores were collected. The remaining respirometers were used as controls; water was collected from the same depth as that of the experimental animals. Once the animals and controls had been collected, the submersible made a slow ascent to the surface. Aboard 674 Table I. Collection and environmental data. Temperature and salinity are the values recorded at the collection depths. n is the number of Biinfundibulum collected in respirometers ("') It:::r Date Dive time Bottom depth Collection depth Temperature Salinity n 3 (m) (m) (0C) (%) ;:;' 2:- .., Q September 13 06:44-08: 18 282 235-238 6.3 33.0 2 3 "C September 14 06:17-07:41 232 187-189 6.1 32.8 2 Q September 17 10:09-12:08 255 133-145 5.1 32.7 3 a: September 18 06:58-08: 15 258 124-130 5.0 32.6 3 .,§ =Q. '"" ....'"' .., Q '"= =3 'S. Q' ...,=Q O:l ~ l:: ::: ~ ".. i:l:: s T.G.Bailey, M.J.Youngbluth and G.P.Owen TEMPERATURE ("C) SALINITY (ppt) 4 6 8 10 12 14 16 18 32.0 33.0 34.0 35.0 0 0 50 50 100 100 §: §. :I: 150 :I: 150 l-a.. I-a.. w w 0 200 0 200 250 250 300 300 CHLOROPHYLL (mg rn") BEAM TRANSMISSION (%T) 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0.5 0.6 0.7 0.8 0.9 0 ~ 0 50 50 100 100 g §. :I: ~ :I: l- 150 150 a.. a..I- w w 0 200 0 200 250 250 300 300 Fig. l. Temperature. salinity, chlorophyll fluorescence and transmissometer data as a function of depth on September 9, 19~9. Closed circles represent depths at which the B.infundibulum used in respiration trials were collected during the cruise. ship, the respirometers were quickly detached from the submersible and transferred to the incubation chamber. Sampling was conducted at night in order to minimize any possible effects of light shock. Incubations were likewise conducted in the dark. Endeco pulsed oxygen probes were used to monitor p02 within each respirometer. The pulse interval for the probes was 15 min. These sensors were profoundly affected by rapid changes in temperature and pressure during a dive. Once constant temperature and pressure were re-established in the shipboard environmental room, the probes stabilized after 3-5 h. Data used to determine rates of oxygen consumption were taken after an 8-11 h acclimatization period in order to allow recovery of both probes (3-5 h) and animals (5-6 h) after ascent to the surface (see Results). Data from the sensors were recorded with an Onset Tattletale datalogger. The datalogger and batteries to power the probes 676 Chemical composition and O 2 consumption of B.infundibulum were contained in a pressure can mounted on the submersible during the dive. The probes and datalogger were activated prior to launching the submersible, and ran continuously until the experiment was terminated ~20 h later. The respirometers were cleaned with I N HCI and then filled with seawater before each dive. As soon as the submersible was launched and the respiro­ meters were submerged, the lids were opened in order to flush the samplers. As the submersible began its descent, the lids were closed to prevent intrusion of material during transit to the operating depth.