Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | colonies 166 µatm and (Bryozoa) and Discussions Fucus serratus ± colonies showed Biogeosciences Alcyonidium foreseen in year 2100 for Electra 2 ect on Electra pilosa ff CO p . At a finer temporal resolution, 2 ect of photosynthetic and respi- ff CO p (Bryozoa) were maintained for 30 days un- 59 µatm and enriched 1193 (Annelida) and 3740 3739 ± are leading to an acidification of the oceans by 0.4 pH ect the benthic communities of calcifiers and macro- 2 ff concentrations. Fragments of the macroalga 2 conditions in the thallus boundary layer where the epibionts live. Spirorbis spirorbis 2 CO p individuals only at the highest CO Alcyonidium gelatinosum conditions: natural 460 p could notably a 1000 µatm) conditions possibly due to the modulation of environmental 2 2 ∼ erent aspects (photosynthesis, respiration and calcification). Seaweeds ff CO p Spirorbis 446 µatm. Our study showed a significant reduction of growth rates and recruit- . On the other hand, the biological activity of the host may substantially modu- ect of Ocean acidification on growth, ± 2 ff CO This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. compared to darkratory hours, activities presumably due ofsignificantly the to increased host the growth alga e ratesgrowth on at rates the 1193 was µatm. carbonate observed. No system. gal Those e macro-epibiontic results communities suggest to a theopen most remarkable elevated ocean resistance ( of theconditions al- by the biological activities of the host alga. the non-calcifier der three 3150 ment of the tubeworm recruits exhibited enhanced calcification of 40 % during irradiation hours are key species ofare nearshore the benthic substratum ecosystems ofspecies of fouling secrete epibionts the calcified like Baltic structures bryozoans Sea.p and and They could tubeworms. frequently therefore Most be oflate impacted those the by pH the and seawater The aim of the presentmunities study to was higher to testbearing the sensitivity the of calcifiers seaweed macrofouling com- Anthropogenic emissions of CO units in the course ofexcess this of century CO according tophytes the in more di severe model scenarios. The Abstract Biogeosciences Discuss., 9, 3739–3766, 2012 www.biogeosciences-discuss.net/9/3739/2012/ doi:10.5194/bgd-9-3739-2012 © Author(s) 2012. CC Attribution 3.0 License. E calcification and recruitment of calcifying and non-calcifying epibionts of brown algae V. Saderne and M. Wahl GEOMAR, Helmholtz Center for Ocean Research, Kiel, Germany Received: 14 March 2012 – Accepted: 18Correspondence March to: 2012 V. – Saderne Published: ([email protected]) 23 MarchPublished 2012 by Copernicus Publications on behalf of the European Geosciences Union. 5 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 3 2 is (ex: CO CO 3 p p 1 CaCO and ≤ in winter as 2 in the atmo- x Electra pilosa (Collatz et al., 2 O − Amphibalanus 2 3 Ω p 2 is an acidic gas 2 Fucus serratus Alcyonidium hirsu- CO p /low CO . When and 2 sp.) this can lead to ex- calc (ex: oysters) (Morse et al., can overgrow fucoidblades CO Ω 250 My) has seen the reduc- p 3 − shift from 280 to 380 µatm (Orr and were investigated regarding their 2 Laminaria rag CO 415 to a Electra pilosa p and several species of Cheilostomes − Ω ions and reduction of seawater pH. This than open ocean waters because of the + 3 3742 3741 Spirorbis spirorbis 1 it tends to precipitate. Surface waters of the Baltic > up to 2500 µatm was recorded (Thomsen et al., 2010; Alcyonidium hirsutum 2 Spirorbis spirorbis CO from 5000 to less than 1000 µatm by intense burial into fossil p 2 CO ecting the entire ecosystems and ultimately stocks of commercially p ff and two bryozoan species, the calcifying cheilostome conditions. In addition, we tested the hypothesis that the diurnally 2 CO ), the tubeworm p , respectively (Oswald et al., 1984). Bryozoans contribute to the degeneration of Within this study we tested the hypothesis that ocean acidification disadvantages cal- growth, calcification and recruitmentder (spirorbis only) three during 30 days of incubation un- sity (Cocito, 2004). They1994) directly and dissolved supply inorganic the carbon (DIC)for host (Munoz grazers algae et such al., with as 1991) ammonium and nudibranchsHarris, are and 1994). (Hurd a urchins et food source (Seed, al., 1976; Harvell, 1984; Nestlercifying and epibionts to the benefitSpirorbis of non-calcifying spirorbis ones. The serpulidand calcifying the tubeworm keratinous Gymnolaete Krumhansl and Scheibling, 2011).tensive In defoliation kelp and forests severely ( impactChapman, 2004), algae a reproduction (spore release)important (Saier species such and as lobstersOn (Wharton the and Mann, other 1981; hand, Scheibling bryozoans et are al., 1999). increasing habitat diversity and improving biodiver- phytes are mostly composedimprovisus of filamentous algae,bryozoans barnacles (Hagerman (mostly et al.,an important 1966). role These in macrofoulers(O’Connor seaweed are and ecology. very Lamont, 1978; importantincreases Kersen for/play in et weight al., and 2011)reduced by presumably brittleness. 50 causing The and shading photosynthetic 85tum and % activity due of to thethe covering underlying by thallus and enhance the risk of breakage by wave action (Dixon, 1981; Saderne, 2012). Tyrrell et al.a (2008) cause suggested of the thethe high absence Baltic of nearshore coccolithophores benthic inand habitats the nursery areas, Baltic. providing food Fucoids primary source1975; are as producer Kautsky key well et services, as species al., spawning substratum 1992). of Macrobial for epibionts macrofoulers associated (Boaden with et Western al., Baltic macro- During upwelling events, tions under the crystalline formechinoderms, of coralline calcite algae), containing followed ascleratinian by high corals), the percentage and of ones finally MgCO under2006; the Fabry the et ones form al., with of 2008;calcite low Ries, aragonite are MgCO 2011). (ex: expressed The by corrosiveness thetends of saturation to seawater states: dissolve to whereas aragonite when and Sea are naturally morelow corrosive alkalinity/salinity to of CaCO thecasional water upwelling added of to deep the hypoxic waters low in temperature summer in (Thomas winter and Schneider, and 1999). the oc- since the preindustrial time,et corresponding al., to a 2005). Theof most 1400 severe µatm scenarios during arecrease predicting the the a corrosiveness 23th of peak century seawater ofskeletons to (Ridgwell atmospheric of the et numerous calcium carbonate marine al., forming species. 2007). the First shells This impacted and transition will will be in- the calcareous forma- 1998; Prentice and Harrison, 2009)late or Paleozoic the (Graham et giant al., arthropodstion 1995). in of That the atmospheric era high ( fuels (COPSE model, Bergman etof al., human 2004). societies Those in stocks the becamesphere. 20th The the ocean century, energy is abruptly source in releasing gaseousand the equilibrium its buried with dissolution CO the leads atmosphere. CO tophenomenon the of release ocean of acidification H is already responsible for a drop of 0.1 pH units Carbon dioxide is essential to theof functioning of photosynthesis the for global ecosystem. production Itgas of is composition organic the is substrate matter a and major driverance gaseous of and oxygen. the spreading Atmospheric evolution of of C4 species. plants Examples since are the the cretaceous appear- with the low 1 Introduction 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 treatment Electra pi- 2 Alcyonidium SD numbers ± CO with microalgae p and treatments. Treated and 3000 µatm CO 2 ) pierced of channels 2 CO sp. to a final concentra- 6.1 colonies of (400 to 500 µatm) during p are colonial filter feeders. ad libitum ± 2 is a filter feeding tubeworm ¨ orde Bay (Western Baltic Sea, Electra pilosa CO , , 6.2 p Alcyonidium . Animals were stained for five days respectively. In this respect, growth E) was used in the experiment, af- 2 0.13 g were cut. Mean 0 ± Rhodomonas 08 ◦ Spirorbis with ambient air (Linde gas and HTK Ham- 3744 3743 ) or keratin ( 16.8 N, 10 2 0 Spirorbis spirorbis (ambient), 1200 µatm CO ± Alcyonidium hirsutum 2 19 Spirorbis spirorbis ◦ . Calcein is a vital fluorescent dye which chelates 1 Electra and − Alcyonidium hirsutum E) on 1 February 2011. 0 . The concentrations of the stock cultures were assessed with 1 53 ◦ − Electra pilosa N, 9 ions, incorporating into growing shells and skeletons and thereby set- 0 individuals fouled by 1.8 colonies of + sp. This microalga species is a convenient food source for bryozoans and 27 2 ◦ ± C. Light was provided by three Biolux neon tubes (Osram, Germany), deliv- ◦ were collected in less than 2m depth in Eckernf levels. and Mg 2 and 1.9 + 2 The bryozoans CO ments were fixed and conserved in borax-formaldehyde-seawater solutions suitable for a continuous mixing(Western of Baltic the Sea, testter Germany, 54 water. storage Natural in BalticConcept a Karlsruhe, seawater 300 l Germany) from and tankrenewed. the aerated and Before with Kiel use, sterilized ambient Bight the air. bylevels The in seawater a three stock was Microfloat separate was equilibrated tanksthird regularly 1 with for day floating 24 the h. and UV The three thetion seawater lamp of of animals (Aqua 10 the fed 000 flasks cells thereafter ml a was with renewed Coulter every Counter (Beckman Coulter, USA). After 30 days of incubation, algal frag- 30 fucus sections(Sarstedt, of Germany) randomly the distributed between initial theflasks three pool were aerated were at incubatedusing 460 µatm an in CO automatic 650 ml systemburg, tissue mixing Germany) CO culture (see flasks Thomsen et al., 2010 for details). The gas bubbling assured losa with calcein/seawater at 50Ca mg l ting a mark for later measurementsComeau of et their al., growth 2009; rates (see Dissard Fig. et 1) al., (Smith 2009). et2.3 al., 2001; Maintenance system ering 300 µE under 12hRhodomonas day/night cycles. Animals werespirorbis fed (Hermansen et al., 2001;alently Lisbjerg fouled and sections Petersen, 2001). of After one twoof fucus days, macrofoulers thallus equiv- per of section 1 were 26.8 room at 15 Algae and animalsseven were days acclimated prior under ambient to the experiment. Cultivation was made in constant temperature of maximum 5 mmby length glands protected located by a under1975). spiraled a Embryos calcified collar are tube. between brooded The the withinparental tube the head body is calcareous (Knight-Jones and secreted tube et the al., incorrelation thorax 1972). an Swimming with (Nott egg non-feeding bag environmental and larvae attached factors. Parkes, aretubeworm to Settlement emitted occur the in and within metamorphosis few hours into (Knight-Jones, a 1951). juvenile 2.2 Acclimation and staining The colonies are composeda of skeleton box of like calcium subunits carbonateconnecting called ( zooids. the They zooids are toenergy protected to their by the neighbors. budding Theseorgans edge of (Lidgard connections the and allow colony Jackson, the making 1989). it allocation a of single organism with deciduous 2 Materials and methods 2.1 Animal collection Fucus serratus hirsutum Germany, 54 layer which are favorable orof disfavorable net for uptake calcification (day) of andrates the net of epibionts release spirorbis (night) recruits during of were times p assessed CO under light and dark conditions and the three fluctuating physiological activity of the host alga will create conditions in the boundary 5 5 25 15 20 10 25 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 er. The fitting of Alcyonidium hir- ff . ers demonstrated an ff Electra pilosa er was immersed in a thermostatic ff C. The temperature corresponding to ◦ (Fischer Scientific, USA). The overall in C accuracy with a Fluke 5658 reference ◦ 1 100 (1) − · 3746 3745   0.01 . DIC was measured with an AIRICA (Marianda, > er voltage (corresponding through the calibration   tot j ff SI 1 n = j X   ln C) reference curve for the electrode in the bu − 0.1 mV) of the pH electrode was measured. The temperature ◦ C with KCl 0.1 mol l ( ± ◦   T j SF 1 n = j X   er was modulated on a range of 1.5 ln ff   the number of colonies in one flask. The logarithmic growth pattern of bry- colonies (non-stainables), were photographed prior and after incubation. The of Perez and Fraga (1987) and Dickson (1990). = C precision for future in-situ pH recalculation (see below). Samples were ana- n − 4 ◦ ers for 15 psu were made according to the SOP 6a of Dickson and Sabine (2007). ff areas were measured and the RGR calculated as for RGR With ozoans colonies have beensutum assessed by Hermansen et al. (2001). Colonies were photographed by overlappingcroscope fields (Axio of Scope vision A1, under Carltial Zeiss, epifluorescence Germany) pictures mi- at were the reassembled end into(SI) of complete the (pre-staining) colony experiment. pictures. and The The the par- initial finalby colony surface image surface (SF) analysis (after (ImageJ, 30 US daysin incubation) National percent were (RGR) Institutes measured was of calculated Health). as The follows: relative growth rate after calibration at 25 situ-pH and carbonate system wasand recalculated Gattuso, with the 2011) R usingfor package first estuarine Seacarb (Lavigne systems and from secondHSO Millero carbonate (2010) system and dissociation the constants dissociations constants2.5 of HF and Measurement of relative growth rates (RGR) of the bryozoans to obtain the laboratory pH onmeasured total the scale climate of room the at sample.pH. The the Preparative temperature work time of conducted of the on sampling sample CRMaccuracy was together of used with this 35 to psu method recalculate bu sured the of in-situ 0.003 to to an 0.005 accuracy pH units. of Salinity 0.01 psu of the with samples a was Mettler mea- Toledo Inlab 738 conductivity probe curve to the sample temperature) were computed through the equation of the SOP 6a temperature corresponding to the calibrationperature range. and the The theoretical sample TRIS voltage, bu sample tem- of the bu every mV change wasthermometer recorded equipped with with a 5608cedure platinum was resistance repeated sensor by (Fluke, increasing USA).voltage and (mV) The decreasing versus pro- the temperature tothe get electrode an voltage average to thefor curve the was natural assessed depolarization onat of every least the measurement once a day electrode. week. to This The check calibration voltage and protocol temperature was of the repeated sample was measured at the of Oceanography). The pH onbu total scale was measured asA follows. Seawater combined TRIS reference/measurement pH electrode Metrohmland) was Ecotrode used (Metrohm, together Switzer- with aToledo, Switzerland). pH-meter/conductimeter For Mettler-Toledo SG calibration, 7/8 the (Mettler bath TRIS and bu the voltage ( standard operating procedure (SOP)flasks 1 in of each treatment Dickson and andeach the Sabine water three exchange. (2007). mixing The tanks temperature Three were of random 0.01 the sampled flasks for and seawater the prior tanks to lyzed were in measured the with laboratory for DICGermany), and pH the measurement principle(g) is purged based out on of thement an Infrared day with acidified measurement Certified sample. of Reference The Material CO (CRM) system (Andrew was Dickson, Scripps calibrated Institution on every measure- recipe) prior to fluorescence microscopy analyses of stained bands2.4 and growth rates. Seawater chemistry Seawater processing for carbonate system measurements was made according to the preservation of calcareous structures (see Maybury and Gwynn, 1993, for the detailed 5 5 20 15 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 2 0.05 CO CO p p ± 6.7 and ± treatments, in the dark, 1 2 166 µatm and − ected by ± ff CO 0.32, 0.83 p and DIC are pre- (one way ANOVA, ± 1.5, 7.63 2 ± tot 0.14) and for calcite ± 4.26 µm d CO 0.001; Fig. 3). The ± p juveniles ≤ p 59 µatm, 1193 on the growth of juvenile worms 0.01) and in the control (Tukey’s ± 2 Spirorbis spirorbis ≤ ected by ff p CO against 46.5 p ected principally the outer spiral of the 1 ff − were 460 0.01) and, marginally, relative to 1200 µatm 2 3748 3747 ≤ Spirorbis spirorbis ect on the juvenile’s growth rates but important p CO ff 6.7 µm d p in the control, 1120 µatm and 3150 µatm treatments ± 1 − SD) SD densities respectively of 1.76 erence (Factorial ANOVA, ± ff ± flsk 1 − SD) below one, for aragonite (0.82 SD of 76.8 0.01). Reductions of growth rates were found at 3150 µatm com- ± . Juvenile tubes growth rates were significantly enhanced under ± ≤ 1 0.1). While no signs of shell injuries were visible at 460 µatm − p ≤ p SD of newly formed tube within 30 days were 0.95 ect of photosynthetic activity and ± ff 0.15 mm worm 0.001) with mean tube growth in mm was estimated as the length of the external arc of the coil ± ) during the last 24 h of the experiment, half of the flasks were kept in constant ect of light on the growth of ≤ 1 0.14) were reached in the 1200 µatm and in the 3150 µatm 445 µatm respectively for the control and the two elevated treatments. Sat- ff − 4.7 juv worm p ± ± Spirorbis spirorbis ± 0.001) (Fig. 2b). The numbers of settled juveniles per adults were significantly ≤ 9.34 light condition, mean corresponding to a 39.5 %treatments di produced no significantdamages e on the earlyand tubes d). were observed in the 3150 µatm treatment (see Fig. 1c (see Fig. 1a andtube b). exposing This the losster. worm of Recruitment soft integrity of bodies a p spirorbis and was the significantly embryolower a at bags 3150 to thanHSD, at the 1200 external µatm (Tukey’s seawa- HSD, The average and 0.58 (Fig. 2a) respectively. The growth of(one spirorbis way ANOVA, tubes was significantlypared a to the 460 µatm(Tukey’s (Tukey’s HSD, HSD, and 1200 µatm, all spirorbis tubes exhibited substantial shell dissolution at 3150 µatm uration states (mean (0.66 respectively. 3.2 3150 ing the 30sented days in duration Table 1. of Average the ( experiment derived from pH and homoscedasticity were testedabnormality with a Shapiro-Wilk’s transformation and by natural Levene’s logarithm tests. was In done. case of 3 Results 3.1 Chemistry A summary of the variables of the carbonate system measured in the flasks dur- 2.8 Statistical analysis Statistical analyses were conducted withcompared Statistica using 7 (Statsoft, one USA). way Treatments were ANOVAs and Tukey’s HSD tests. Assumption of normality found on algae sections at the end of the2.7 experiment divided by E the number of adults. To test the e in the thallus boundary20 layer, mg l calcein was addedlight, to the all other the half flaskssize was of (final darkened the concentration: stained with newly aluminum formed foils. tube Growth (see Fig. was 1c measured and as d). the Spirorbis comprised between the stainingflask, front the and the new tube tubeworms. edge length Spirorbis (see recruitment of Fig. was all 1a quantified and worms for b). each was In flask summed each as and the divided number of by juveniles the number of 2.6 Measurement of growth and recruitment of 5 5 15 20 10 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | . was levels: (Rucker 2 3 Myriapora the thallus 18.1 %). In CO ff ± 1 (3150 µatm p Electra pilosa ≤ is not negatively (one way ANOVA, calc were marginally af- 1 mm o Ω < 32.2 %) (Tukey’s HSD, Spirorbis spirorbis ± was noted for treatment (50.7 0.1; Fig. 4b). 2 2 . In this treatment, adults and ju- Electra pilosa but by irradiation, attesting to a 2 (sub-order: Malacosteginae, this p > Electra pilosa CO 2 p CO p Electra on the calcifying organisms living in the were similar under all 3.08 but dissolution of dead zooid skele- Alcyonidium hirsutum = 40.8 % in the 1200 µatm treatment and 3750 3749 ± and Fucus calc Ω regardless of the nature of their skeletons. However, skeletons dissolved only when 2 Alcyonidium , and CO and even stimulated at 1200 µatm. However, the empty ected directly by 2 p ff ect on growth rates of 2 ff , (sub-order: Ascophorae, Smith et al., 2001) but not with CO CO Electra pilosa p , pH) have been shown to fluctuate by orders of magnitude be- p 2 treatment, the skeleton of uninhabited zooids dissolved completely, Electra pilosa vents of Ischia (Italy), Rodolfo-Metalpa et al., (2010) found mainte- 2 ecting the physiology of the incrusted animals (Woods and Podolsky, . Their skeleton is exclusively calcitic with 7 to 10 % of MgCO 2 ff CO ect of photosynthesis of ects of external living tissues and organic layers over calcified structures p Adeonellopsis ff ff at 1400 µatm 17.9 % in the 3500 µatm treatment (ANOVA, (sub-order: Flustridae, Fortunato and Saderne, unpublished), suggesting dif- 31.7 %), relative to the highest level, 3150 µatm (43.0 had a significant e 25.5 % in the control, 36.5 ± ± 2 ± 0.05) enhancing colony growth at the intermediate0.01) acidification (Fig. level, 4a) 1200 µatm which was similar to the low Electra pilosa ected by very high ected in its growth and recruitment at 3150 µatm CO Relative growth rates of ≤ ≤ CO ff ff evolved calcareous skeletons polyphyletically on at least two distinct occasions and calcein staining could givethat a calcein first staining of clue biomineralizedter. into structures The the implies classes direct process. of vacuolization Bentov of calcifiersto et seawa- using the al. this environmental mechanism (2009) pH areuse suggest (Weiner presumably external and the seawater Dove, most at 2003; sensitive theata, Weiner sites calcein and of staining Addadi, calcification. worked 2011)study) Within with as the and the they order genera ofFlustra the Cheilostom- ferent mechanisms of calcification within the cheilostomes. Cheilostome bryozoans less, both our results corroboratethe the skeletons important of role bryozoans, of presumablyprotective the creating e a zooidal tissues barrier surrounding to corrosivehave seawater. already Such beenCalcification observed processes in in mussels bryozoans and are corals largely (Rodolfo-Metalpa unstudied but et the al., functioning 2011). of the of and Carver, 1969; Smith et al.,of 2006; Taylor this et al., sub-order 2009), in reminiscent the ofthe calcitic the appearance natural seas of CO thenance late Jurassic/Cretaceous of (Stanley, growth 2006). In andtruncata calcification of transplanted coloniestons. of Dead the Baltic bryozoan treatment) and therefore seem more resistant to seawater corrosiveness. Neverthe- Our results suggest thata the growth inzooids the lost their bryozoan calcifiedrated structures with at regard 3150 to µatm, calcite. when These the results seawater could was be explained undersatu- by the known mineralogy 4.1 Bryozoans boundary layer surrounding thesurface) thallus. conditions (O In thetween boundary light layer and ( darket phases al., (De 2010), Beer a 2007). and Larkum, The 2001; bryozoans Beerfected in et their al., growth by 2008; the the Spilling dissolution of the empty skeletons at 3150 µatm CO The present study demonstrateda that the calcifying tubeworm veniles shells were exhibiting importantof damages the due to juveniles dissolution. wereprotective The e not growth rates a this highest resulting in a “ghost” organic matrix of the exact27.2 same shape. 19.18 4 Discussion p p (76.5 p 3.3 Bryozoans 5 5 25 15 20 10 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 by er- ff CO p blades by its , less competitive ected by seawater ff Fucus erence in mineralogy ff Hydroides crucigera followed the same pat- 2 specifically settles on brown CO Alcyonidium p to tubes are bimineralic with 40 % arago- tends to dominate (Bornhold and Milliman, 1973). Generally, 3 3752 3751 of Spirorbis spirorbis Spirorbis spirorbis exposed to acidified seawater (Ries, 2011). There- erence might be due to the di Electra pilosa ff ) larvae, becoming “blind” to their host anemones cues Alcyonidium hirsutum Hydroides crucigera but with growth rates 50 % slower. These results are simi- Spirorbis spirorbis Hydroides crucigera Electra pilosa Amphiprion percula er from previous results obtained on the serpulid polychaete The growth response of ff pH and making the larvaeclown incapable fish of ( recognizing their hosts. This has been found in esis accidents have been notedet for gastropods, al., bivalves 1996; and Kurihara echinodermsanother and (Desrosiers sensitive Shiryama, life 2004; stage Ellis forterious et invertebrates (Dupont on al., which et 2009). ocean al., Thethe acidification 2008; planktonic pelagic can phase stage Kurihara, be (a is 2008). few dele- minutes Inreduce to the 3 Spirorbis, impact h) of however, and acidified the the seawater. non-calcifyingalgae shortness nature and of of this the preference larvae is may 1985; most Qian, likely chemically 1999). mediated The (De necessary Silva, 1962; sensitivity Al-Ogily, to cues could be a experiment since sperm storedhead during the could previous have summer been1977). in used Likewise, a some to specific embryos fertilize organ inhave the of dormancy seen the eggs at their the (Potswald, development reactivated. beginning 1967;esis A of Daly is delaying the or and a experiment interruption possible Golding, could of explanationto for the external our embryogen- acidified results, seawater due after to dissolution the of exposition the of parental the tubes. embryo Such bags embryogen- ing on seawater temperature(Knight-Jones, (Daly, 1951). 1978) In and ourTheir settlement experiment number the occurs was reduced first within by juvenilesification 80 a % appeared condition. few in after This the hours two was 3150 µatm weeks. associatedeggs treatment with bags relative the to in the observation the lowinvertebrates: of adult acid- fertilization, tubes. numerous cleavage Kurihara unspawned (embryogenesis), (2008) planktonic identifiedmetamorphosis. larva, Accidents five settlement having critical and happened to early those liferesults. early Exchange stages life of stages in sperm could and explain our fertilization of eggs might not have occurred during the of adaptation of calcification to corrosive waters. 4.3 recruitment and juvenile growth Breading of Spirorbis larvae in the parental tube varies between 10 to 25 days, depend- even if the absence of organic covering protecting their tubes might limit their capacities fore, we may expect that tubeworm response to ocean acidification is species-specific serpulids exhibit a widebeing bimineralic variety (Vinn of et tubesaturation al., state 2008). ultrastructure of Their and seawater. mineralogy In mineralogy,calcite seems exclusively most in to calcitic of serpulids, be tubes predominance modulated them istropical of by species observed low the (Bornhold Mg at and highrelationship Milliman, between latitude 1973). seawater in In corrosiveness and bimineralic coldserved low species, corrosive aragonite no (Bornhold content seawater geographic in and compared tubesobserved Milliman, is to ob- for 1973), even if in culture a reduction in aragonite is di Ries et al. (2009).from They found 280 a to linear 2800between decrease µatm. the of This two calcification di species. withnite increasing and 60 % calcitealmost including exclusively 20 calcitic % with Mg 15 % calcite MgCO (Ries, 2011), while spirorbis tubes are rapid growth rates (Rylandfor and space, seems Stebbing, more 1971)1978). ubiquist while in term of habitats colonized (O’Connor4.2 and Lamont, Calcification of Reduction of growth andundersaturation shell for damages calcite were at the observed highest only level when of acidification seawater (3150 reached µatm). Our findings ent calcification mechanisms (Jablonski2009). et al., 1997; Smith et al., 2006;tern Taylor et as al., for lar to observations in the field. as a consequence possess diverse calcified structures that could be based on di 5 5 25 15 20 10 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 CO p Spirorbis provoking a ff ected by global ff resisted future . Algal metabolites have an in- 2 ects can be direct (e.g. Wahl et al., CO ff p Fucus serratus takes place in the boundary layer adhering 3754 3753 uptake associated with photosynthesis (Fischer and 2 to more than 2500 µatm (Thomsen et al., 2010; Saderne ect on foulers. Those e ff ´ 2 evreux., J. Exp. Mar. Biol. Ecol., 86, 285–298, 1985. Spirorbis spirorbis CO shore winds may lead to an upwelling of deoxygenated deeper p ff ner et al., 2007; Martin et al., 2008). Our study does not suggest We thank M. Fischer, C. Hiebenthal, C. Howe, B. Huang Xuan, ¨ ff awe and Burchard, 2011). Locally, in the nearshore ecosystems of observed in Mediterranean seagrasses due to the disappearance of (Munday et al., 2009). Reduction of settlement could also be caused erent parameters: increase of mean sea surface temperature by 2 ff 2 2 CO CO ect. In our experiment, epibionts of L’Hardy and Qui p p ff C, strengthening of westerly wind, increase of the river run o is predicted to increase, however the amount of this increase remains unknown ◦ 2 inornatus ate and its roles in biomineralization, Adv. Mat., 15, 959–970, 2003. As a novel aspect of epibiotic associations, our study strongly suggests that juve- CO Al-Ogily, S. M.: Further experiments on larval behaviour of the tubicolous polychaete Addadi, L., Raz, S., and Weiner, S.: Taking advantage of disorder: amorphous calcium carbon- Acknowledgements. C. Lieberum, K.for Maczassek their and field C. assistancefunded Pansch, by and Y. the Sawall J.-P. European Gattuso and community, Marie for the Curie providing crew ITN access CALMARO of (PITN-GA-2008-215157). to the the F. Airica. B.References This Polarfuchs work was host algae. This study illustrates,microhabitat however, that scale small must scale be processesspecies considered at and when the communities. habitat assessing or the impact of acidification on decrease of sea surface(Schrum, salinity 2001; Gr and increasethe of Western Baltic, inputs o ofwater dissolved increasing organic the carbon et al., 2012). Strengthening ofanoxic events) these might winds prolong plus the duration enhancedeven of epibionts eutrophication in those (intensifying the hypercapnics boundary events. Consequently, layerchange of macroalgae directly may – ultimately and be a also indirectly by shifts in the physiology and distribution of their lus boundary layerp where the epibionts(Schneider, occur. 2011). Like This in incertitudeposite is the caused shift global by of ocean, the di to simultaneous Baltic but 3.5 Sea sometimes op- by the alga’s photosynthetic activity overriding the simulated acidification in the thal- such an e conditions predicted for the open ocean. Part of this resistance may have been caused 5 Conclusions One widespread expectation about oceanwill acidification outcompete is calcifying that organisms non-calcified (Fabryand seaweeds organisms et (Diaz-Pulido al., et 2008) al., asunder 2011). A observed high shift between to corals non-calcifyingcoralline epibionts is algae observed (Ku due to algal respiration seemsSpilling marginal (De et Beer and al., Larkum,stands 2010). 2001; Beer of We et marine al., may macrophytes 2008; photosynthesis expect (algae, pushes that seagrasses) the habitat’s where similar saturation thecalcifiers phenomena state in to population’s take the favorable combined conditions community place and to allows in produce skeleton natural material during certain daylight hours. nile spirorbis benefit fromfavorable for algal calcification even photosynthesis under which severejuveniles ocean was creates acidification. about The temporarily 40 growth % conditions ratesis faster of under and the light early than growth into of the the dark. thallus Settlement, surface of metamorpho- to Fucus. beyond In 9 this in layer daytime of by 300Saderne, the µm CO unpublished to 1 data). mm thick, Under pH dark can be conditions, pushed in contrast, the decrease of pH by an increase of thehibiting algae and/or facilitating defenses e at elevated 2010), or indirect byet the al., mean 2002; of Nasrolahi et thedefenses al., have microbial 2012). been biofilms So made. 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All photos were taken under epifluorescence micro- p < : Spirorbis spirorbis Spirorbis spirorbis • , data are the mean 2 tubes after 30 day incubation at 460 µatm and 3150 µatm CO 0.05, Recrutement of ≤ p (B) Electra pilosa (E) . 0.01, *: ≤ (D) Growth of the tubes of Spirorbis spirorbis p tubes after 30 day incubation at 460 µatm and 3150 µatm CO Illustrative examples of 0.001, **: settled per adult between flasks. One-way ANOVAs, per worm per flask. 460 µatm, 1200 µatm and 3150 µatm CO Fig. 2. (A) 1200 µatm and 3150 µatm CO Fig. 1. Juveniles spirorbis respectively. Note the important dissolutionthe of tube the in shell inscope, B. yellow/green: and calcein the staining.for disappearance The of the part white growth of lines measurementssubsequent are to of the showing spirorbis calcein the staining tubes. considered in Arrows distances indicate the direction of the growth Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | colonies . Data are the 2 during 24 h in light and Alcyonidium hirsutum (B) , Spirorbis spirorbis 10 flasks. ANOVA, statistical significance: **: = 3766 3765 Electra pilosa n (A) 0.001. ≤ of 460 µatm, 1200 µatm and 3150 µatm. Two-way ANOVA, p 2 CO p SD of the growth rates in % in Relative growth rate (RGR) of Growth in µm of the tubes of the juveniles of ± 0.01. 5, statistical significance: ***: ≤ = p during the 30mean days incubations at 460 µatm, 1200 µatm and 3150 µatm CO Fig. 4. n Fig. 3. dark condition exposed to