JOURNAL OF PLANKTON RESEARCH j VOLUME 34 j NUMBER 7 j PAGES 642–645 j 2012 SHORT COMMUNICATION A weight- and temperature-dependent model of respiration in Praunus flexuosus (Crustacea, Mysidacea) Downloaded from https://academic.oup.com/plankt/article/34/7/642/1465303 by guest on 01 October 2021 MARTIN OGONOWSKI*, KRISTOFFER ANDERSSON AND STURE HANSSON DEPARTMENT OF SYSTEMS ECOLOGY, STOCKHOLM UNIVERSITY, SE-106 91 STOCKHOLM, SWEDEN *CORRESPONDING AUTHOR: [email protected] Received February 1, 2012; accepted in principle March 15, 2012; accepted for publication March 20, 2012 Corresponding editor: Marja Koski The mysid shrimp Praunus flexuosus is common in littoral habitats in the Baltic Sea and other marine areas, but its bioenergetic characteristics have not been studied. We present the first model of its routine respiration rate as a function of size and a natural temperature range. The model explained 87% of the variance in respir- ation, indicating that it could be useful in a larger modeling framework. Specific respiration rates and temperature dependence were consistent with previous reports for this and other littoral mysids at low-to-moderate temperatures. Respiration at higher temperatures was lower, indicating that previous reports may have been biased by residual SDA (specific dynamic action) effects. Increased res- piration due to SDA was detectable over a longer period than previously reported, 30 h. KEYWORDS: respiration; Praunus flexuosus; fasting; specific dynamic action; routine metabolism compared with what are available for fish (Hanson INTRODUCTION et al., 1997). One important component of such models Mysids are a significant component of aquatic ecosys- is respiration, since it constitutes a major component in tems and are important links between different trophic the energy budget. Respiration can, however, be some- levels (Mauchline, 1980). They are important zooplank- what problematic to describe with a model, since it is ton predators (Rudstam et al., 1986) as well as a food influenced by many factors, both biotic (e.g. size, repro- source for many species of fish (Arndt and Jansen, duction, ontogeny) and abiotic (e.g. temperature, salin- 1986). To understand their role in the food web, we ity, season). Among these, temperature and size are need quantitative analyses of their food consumption regarded as being particularly influential (Winberg, and bioenergetics models can provide such estimates. 1956). Although there are some studies that have There are some bioenergetics models published for reported on mysid respiration in the past (Vlasblom and mysids (Rudstam, 1989; Gorokhova, 1998), but few Elgershuizen, 1977; Laughlin and Linden, 1983; Weisse doi:10.1093/plankt/fbs030, available online at www.plankt.oxfordjournals.org. Advance Access publication April 16, 2012 # The Author 2012. Published by Oxford University Press. All rights reserved. For permissions, please email: [email protected] M. OGONOWSKI ET AL. j PRAUNUS RESPIRATION AND EFFECTS OF FASTING and Rudstam, 1989), few have produced an adequate Table I: Summary of the experimental design model of respiration that could be incorporated in a showing the four different temperature larger modeling framework. treatments (Temp, 8C), number of mysids (n), In this study, we present a weight- and temperature- number of controls (c), average specific dependent respiration model for the common littoral respiration (mgO dw21 h21), dry weight of mysid Praunus flexuosus, based on experiments that 2 covered substantial temperature and size ranges (3–198C mysids (DW, mg) and duration of the and 2–9 mg dry weight). To our knowledge, this is the experiments (h) first model relating the effects of temperature and weight Respiration 21 21 on oxygen consumption in P. fl e x u o s u s . Temp (8C) nc(mgO2 dw h ) DW (mg) Duration (h) Mysids were collected with a hand net (300 mm 18.7 + 0.6 17 4 2.3 + 0.44 4.9 + 1.6 30 Downloaded from https://academic.oup.com/plankt/article/34/7/642/1465303 by guest on 01 October 2021 mesh) in a bladder wrack (Fucus vesiculosus) belt in the 16.4 + 0.5 16 4 1.6 + 0.45 5.9 + 1.5 29 0 0 8.2 + 0.6 17 4 0.8 + 0.15 6.2 + 1.1 37 northern Baltic Proper (58849 N, 17838 E), where 3.1 + 0.3 17 4 0.7 + 0.18 6.8 + 1.5 35 surface temperature ranged 10–128C. Specimens for All values are expressed as the average + standard deviation when experiments [immature males, immature females and applicable. undifferentiated juveniles (88% of sample)] were cap- tured between 21 September and 9 October 2009 and acclimated to the experimental temperature by keeping cone was put on the top of every bottle. Although all them in a constant temperature room in 10-L buckets experiments were conducted in darkness, the black with aerated, micropore (0.22 mm) filtered sea water plastic cover was applied to minimize any stress on the (salinity, 6.8 psu). Mysids were first starved for 17–27 h animals that might have arisen from temporary light depending on the temperature treatment as gut evacu- when measurements were taken. To avoid effects of ation time is negatively related to temperature, making hypoxic stress, we did not allow any experimental unit sure that all potential food in the gut had been pro- to fall below 65% air saturation. After each experiment, cessed. Gut residence times in Mysis relicta are ,6h at the animals were dried for 48 h at 608C and weighed 5–158C(Chipps, 1998) and 4–12 h for Neomysis integer to the nearest milligram. Oxygen concentrations were fed Artemia salina nauplii at 158C(Fockedey, 2005) and measured with a Fiber-optic oxygen mini-sensor (Fibox we have assumed similar values for P. flexuosus.To 3 PreSens Precision sensing GmbH Regensburg, further standardize conditions, following starvation, the Germany). Prior to the experiments, sensor spots were mysids were allowed to feed ad libitum on newly hatched attached with silica glue to the inside of the bottles, and A. salina nauplii for 6 h before the start of the experi- during the experiments, oxygen concentration was mea- ments. This was done in order to more closely reflect sured from the outside of the bottle using a DP-PSt3 natural conditions since mysids normally feed several fiber-optic probe. The temperature was measured separ- times per day (Tattersall and Tattersall, 1951; Garnacho ately, in a water filled bottle, by a Fibox 3 unit with a et al., 2001). However, as there are metabolic costs asso- PT 1000 Sensor. 21 21 ciated with the processing of food (specific dynamic Individual respiration y (mgO2 ind. h ) at time t action, SDA), we only used respiration rates at the end was calculated by fitting an exponential function of the of the experiments to derive model parameters for form: routine respiration, i.e. when SDA effects were assumed bt to be negligible. yðtÞ ¼ ae ð1Þ A total of four experiments with different tempera- tures (3, 8, 16 and 198C, Table I) were conducted. where a is the intercept, b a constant and t the time Oxygen concentration in the incubation water (see (h).Taking the first derivative of that function yielded below) was measured at 1–1.5 h intervals over a weight-specific routine respiration at time t expressed as: period of 30 h. All experiments were run in a con- stant temperature room. Single mysids were placed in ab ebt V ¼ ð2Þ 330-mL plastic bottles wrapped in black light- ðtÞ w impermeable plastic. In addition to these bottles, there were four bottles in each experiment that contained no where w is the dry weight (mg) (r2 of exponential model mysid and were used to control for background oxygen fit: 25–75% interquartile range ¼ 0.94–0.99, min ¼ consumption. The bottles were filled with filtered sea 0.71, max ¼ 0.99). All controls (bottles without mysids) water and a watch glass was slid on the top of the bottle displayed a low, but linear, decrease in oxygen concen- in order to expel any air bubbles. Finally, a black plastic tration over time. To account for this, background 643 JOURNAL OF PLANKTON RESEARCH j VOLUME 34 j NUMBER 7 j PAGES 642–645 j 2012 3°C 4 1:1 line 3 2 1 8°C ) 4 –1 ) –1 h 3 h –1 2 2 O dw 1 2 O 16°C Predicted respiration (µg 4 R (µg 3 2 Downloaded from https://academic.oup.com/plankt/article/34/7/642/1465303 by guest on 01 October 2021 1 19°C 4 0 5 10 15 20 3 2 0 5 10 15 20 1 Observed respiration –1 10 20 30 (µg O2 h ) Time (h) 21 21 Fig. 1. Observed versus predicted respiration values (mgO2 ind. h ). ¼ 2 ¼ Fig. 2. Mean (circles) + standard deviation (whiskers) weight-specific Dashed line represents a theoretical 1:1 relationship. n 67, r 0.87. 21 21 respiration (mgO2 ind. h ) over the course of the 30-h incubation at four temperatures (3, 8, 16 and 198C). n ¼ 17 in all cases except at 168C where n ¼ 16. respiration (estimated by the slope of a linear regression) was substracted from individual mysid respiration values. All statistical calculations were made in R et al.(Garnacho et al., 2001) studied seasonal effect on v. 2.13.0 R (R development core team 2011). Praunus respiration and reported values of 0.97– 21 21 We used the non-linear least squares “nls” function in 1.82 mgO2 mg dw h at 58CinFebruaryandan 21 21 the “nlme” package (Pinheiro et al., 2011) to find the average 3.0 O2 mg dw h at 208C in August. In parameters for our model.