Table 1.

Summary of the impacts of ocean acidification on juvenile and adult molluscs.

Species	Experiment Duration	CO2/pH range	Measured	Impact	CO2/pH level that first caused an impact	Author
BIVALVES
Acesta excavata (clam)	4 d	530, 33,000 µatm 8.12, 6.35	Respiration	↓/=	−1.72 (33,000 µatm) −1.72 (33,000 µatm) −1.72 (33,000 µatm)	[161]
			Excretion	=
			pHe	↓
			pHi	↓
Argopecten irradians (scallop)	60 d	370, 547, 892, 2,551 ppm 8.15, 8.02, 7.83, 7.45	Calcification	↓	−0.13 (547 ppm)	[48]
Chamelea nobilis (clam)	7 d	n/a	Immune response	Changes	−0.4	[135]
		8.1, 7.7, 7.4
		+Temp. 22, 28 °C
		+Salinity 28, 34, 40
Chlamys nobilis (scallop)	2 h	n/a 8.1, 7.7, 7.4	Respiration rate	↓	−0.4	[158]
			Clearance rate	↓	−0.4
			Excretion rate	↓	−0.4
Crassostrea gigas (oyster)	14 d	380, 740 ppmv n/a	Calcification	↓	−0.2 (740 ppmv)	[45]
	30 d	n/a	Shell density	↓	−1.2	[55]
		8.2–5.4	Shell weight	↓	−1.2
	55 d	582, 1480 ppm	pHe	↓	−0.39 (1,480 ppm)	[137]
		8.07, 7.68	PeCO2	↑	−0.39 (1,480 ppm)
		+Temp. 15, 25 °C	PeO2	=
			CeCO2	↑	−0.39 (1,480 ppm)
			HCO3−	↑	−0.39 (1,480 ppm)
			Ca2+	=
			Na2+	↓	−0.39 (1,480 ppm)
			K+	↑	−0.39 (1,480 ppm)
			Tissue metabolite levels	↓	−0.39 (1,480 ppm)
			Metabolic rate (+temp.)	↑	−0.39 (1,480 ppm)
Crassostrea virginica (oyster)	15 h	n/a	Calcification (+salinity)	↓	−0.63	[30]
		8.29, 7.66, 7.56
		+Temp 20, 30 °C
		+Salinity 16, 32
	14–140 d	380, 3500 µatm 8.2, 7.5	Survival	↓	−0.7 (3,500 µatm)	[40]
			Shell growth	↓	−0.7 (3,500 µatm)
			Somatic growth	↓	−0.7 (3,500 µatm)
			Shell ultrastructure	↓	−0.7 (3,500 µatm)
			Respiration rate	↑	−0.7 (3,500 µatm)
	60 d	370, 547, 892, 2551 ppm	Calcification	↓	−0.13 (547 ppm)	[48]
		8.15, 8.02, 7.83, 7.45
	77 d	400, 700–800 µatm 8.11, 7.97 (Sal 15) +Salinity 15, 30	Survival	↓	−0.14 (700–800 µatm)	[140]
			Tissue energy stores	↓	−0.14 (700–800 µatm)
			Somatic growth	↓	−0.14 (700–800 µatm)
			Tissue ATP	=
			Carbonic anhydrase	=
	14 d	n/a	Shell dissolution	↑	−0.23	[62]
		7.9, 7.67, 7.38, 7.17
	14 d	395, 3,617 ppm	Oxidative stress	↑	−0.8 (3,617 ppm)	[66]
		8.3, 7.5	Cytoskeletal proteins	↑
Laternula elliptica (clam)	28 d	390, 2,639 µatm	Shell dissolution	↑	−0.6 (2,639 µatm)	[54]
		8.2, 7.4
	120 d	187 *, 438, 735 µatm 8.32 *, 7.99, 7.78	Metabolic rate	↑	−0.21 (735 µatm)	[152]
			HSP70 expression	↑	−0.21 (735 µatm)
			Chitin synthase expression	↑	−0.21 (735 µatm)
Mercenaria mercenaria (clam)	14 d	Ωarag 1.2, 0.6, 0.4	Survival	↓	−0.6 (Ωarag 0.6)	[153]
		7.9, 7.3, 7.0
	60 d	370, 547, 892, 2551 ppm	Calcification	↓	−0.7 (2,551 ppm)	[48]
		8.15, 8.02, 7.83, 7.45
	8 h	424, 1,120, 1950 µatm	Calcification	↓	−0.38 (1,120 µatm)	[61]
		8.02, 7.64, 7.41
Mya arebaria (clam)	60 d	370, 547, 892, 2551 ppm	Calcification	↓	−0.13 (547 ppm)	[48]
		8.15, 8.02, 7.83, 7.45
Mytilus chilensis (mussel)	70 d	380, 750, 1200 ppm7.91, 7.71, 7.57	Respiration rate	↓	−0.34 (1,200 ppm)	[160]
			Excretion rate	=
			Ingestion rate	=
			Clearance rate	↓	−0.34 (1,200 ppm)
			Adsorption rate	↓	−0.34 (1,200 ppm)
Mytilus edulis (mussel)	2 h	380, 740 ppmv	Calcification	↓	−0.2 (740 ppmv)	[45]
		n/a
	30 d	n/a	Shell density	↓	−1.2	[55]
		8.2–5.4	Shell weight	↓	−1.2
	32 d	665, 1,161, 1435, 3316 µatm	Immune response	↓	−0.1 (1,161 µatm)	[144]
		7.8, 7.7, 7.5, 6.7	Immune surveillance parameters	=
	44 d	n/a	Survival	↓	−0.5	[60]
		8.1, 7.6, 7.4, 7.1, 6.7	Shell growth	↓	−0.5
	14–56 d	385, 560, 840, 1120, 1400, 4000 µatm 8.05, 7.89, 7.81, 7.7, 7.56, 7.08	Shell growth	↓	−0.49 (4,000 µatm)	[79]
			Somatic growth	=
			pHe	↓	−0.49 (4,000 µatm)
			PeCO32−	↓	−0.49 (4,000 µatm)
			PeCO2	↑	−0.49 (4,000 µatm)
			HCO3−	=
			Ca2+	=
			Na2+	↑	−0.49 (4,000 µatm)
			K+	=
			Mg2+	=
	2 mo	385, 1120, 2400, 4000 µatm 8.03, 7.7, 7.38, 7.14	Shell growth	↓	−0.33 (1,120 µatm)	[51]
			Somatic growth	=
			Metabolic rate		−0.33 (1,120 µatm)
			NH4+ excretion rate	↑	−0.33 (1,120 µatm)
	2 mo	385, 1120, 2400, 4000 µatm 8.03, 7.7, 7.38, 7.16	Shell growth	↑	−0.65 (2,400 µatm)	[59]
			Gene expression (tyrosinases)	↓	−0.65 (2,400 µatm)
			Gene expression	↓	−0.65 (2,400 µatm)
			(chitinases)
	60 d	370, 547, 892, 2551 ppm	Calcification	=		[48]
		8.15, 8.02, 7.83, 7.45
	35 d	472, 1021, 2114, 3350 µatm	Shell length	=		[65]
		8.01, 7.7, 7.4, 7.19	Inorganic shell growth	↓	−0.31 (1,021 µatm)
		+Food high, low	Organic shell growth	=
Mytilus galloprovincialis (mussel)	7 d	n/a 8.1, 7.7, 7.4 +Temp. 22, 28 °C +Salinity 28, 34, 40	Immune response	Changes	−0.4	[135]
	78 d	963, 1989, 3790 µatm 8.03, 7.74, 7.48	Somatic growth	↑	−0.3	[159]
			Absorption efficiency	↑	−0.3
			Ammonium excretion	↑	−0.3
			Excretion rate	↑	−0.3
			Clearance rate	=
			Ingestion rate	=
			Respiration rate	=
	3 mo	0.82, 3.82 mmHg CO2 8.05, 7.3	Shell growth	↓	−0.75 (3.82 mmHg)	[43]
			Metabolic rate	↓	−0.75 (3.82 mmHg)
			pHe level	↓	−0.75 (3.82 mmHg)
			Protein degradation	↑	−0.75 (3.82 mmHg)
			HCO3−	↓	−0.75 (3.82 mmHg)
			Ca2+	↓	−0.75 (3.82 mmHg)
	84 d	805, 1,698, 4,345 µatm 8.13, 7.84, 7.46	Survival	=	−0.67 (4,345 µatm)	[63]
			Shell growth	↓
			Tissue growth	=
Ostrea edulis (oyster)	30 d	n/a	Shell density	↓	−1.2	[55]
		8.2–5.4	Shell weight	↓	−1.2
Pecten maximus (scallop)	30 d	395, 1,086 µatm	Clapping performance	↓	−0.43 (1,086 µatm)	[165]
		4 °C: 8.19, 7.76	Aerobic scope	↓	−0.43 (1,086 µatm)
		10 °: 8.25, 7.81
		(+temp. 4, 10 °C)
Perna viridis (green-lipped mussel)	2 h	n/a 8.1, 7.7, 7.4	Respiration rate	↓	−0.4	[158]
			Clearance rate	↓	−0.4
			Excretion rate	↓	−0.4
Pinctada fucata (pearl oyster)	2 h	n/a 8.1, 7.7, 7.4	Respiration rate	↓	−0.4	[158]
			Clearance rate	↓	−0.4
			Excretion rate	↓	−0.4
	28 d	n/a 8.1, 7.8, 7.6	Shell strength	↓	−0.3	[52]
Ruditapes decussatus (clam)	75 d	8.05, 1698, 4345 µatm 8.13, 7.84, 7.46	Survival	↑	−0.39 (1,698 µatm)	[72]
			Calcification	=
			Shell growth	=
			Weight	=
	87 d	730, 1813, 3702 µatm 8.16, 7.82, 7.53	Respiration rate	↓	−0.4	[157]
			Clearance rate	↓	−0.4
			Ingestion rate	↓	−0.4
			Excretion rate	↑	−0.4
Ruditapes philippinarum (clam)	28 d	n/a	Metal uptake	↑	−1.0	[113]
		8.5–6.5
Saccostrea glomerata (oyster)	4 d	375, 1000 ppm	Shell growth	↓	−0.36 (1,000 ppm)	[53]
		8.2, 7.84
Yoldia eightsi (clam)	35 d	390, 2639 µatm	Shell dissolution	↑	−0.8 (2,639 µatm)	[54]
		8.2, 7.4
Community	30 d	729–3010 µatm	Structure	↓	−0.3	[138]
		8.0, 7.7, 7.3, 6.7
		(+Temp. 12, 16 °C)
GASTROPODS
Creithium vulgatum (snail)	ecosystem	304–20812 µatm	Shell strength	↓	−0.7	[46]
		8.17–6.57
Clio pyramidata (pteropod)	2 d	Ωarag > 1, < 1	Shell dissolution	↑	−0.35 (Ωarag >1)	[5]
Crepidula fornicata (limpet)	60 d	370, 547, 892, 2551 ppm	Calcification	↑	−0.13 (547 ppm)	[48]
		8.15, 8.02, 7.83, 7.45
Hexaplex trunculus (snail)	ecosystem	304–20812 µatm	Shell strength	↓	−0.7	[46]
		8.17–6.57
Limacina helicina (pteropod)	5 d	350, 760 µatm	Calcification	↓	−0.3 (760 µatm)	[47]
		8.1, 7.8
	4 - 14 d	4 d: 318, 940 µatm 4 d: 8.13, 7.7 14 d: 318, 883 µatm 14 d: 8.13, 7.73	Dissolution	↑	−0.43 (940 µatm)	[56]
			Dissolution	↑	−0.4 (883 µatm)
	29 d	180 *, 380, 750, 1150 µatm	Survival	↓	−0.43 (1,150 µatm)	[49]
		8.27 *, 8.12, 7.81, 7.69	Shell growth	↓	−0.31 (750 µatm)
		(+temp.: 3, 5.5, 8 °C)	Shell degradation	↑	−0.31 (750 µatm)
Limacina retroversa (pteropod)	8 d	280 *, 350, 750, 1000 ppm	Shell growth	↓	−0.2 (750 ppm)	[57]
		8.2 *, 8.0, 7.8, 7.6	Shell dissolution	↑	−0.2 (750 ppm)
Littorina littorea (periwinkle)	15 d	n/a 7.97, 6.63	Predator avoidance	=		[58]
			Predator avoidance (+predator cue)	↑	−1.34
			Respiration rate	=
			Respiration rate (+ predator cue)	↓	−1.34
			Shell thickness	=
			Shell thickness (+predator cue)	↓	−1.34
	60 d	409, 606, 903, 2856 ppm	Calcification	↓	−0.09 (606 ppm)	[48]
		8.09, 8.00, 7.86, 7.42
	30 d	428, 998 µatm 8.03, 7.67	Shell length	↓	−0.36	[64]
			Shell weight	↑
			Shell thickness	↓
			Aspect ratio	↓
	30 d	428, 998 µatm	Metabolic rate	↓	−0.36	[162]
		8.03, 7.67	Energy metabolites (ATP)	↓
Nacella concinna (limpet)	14 d	Ωarag 2.66, 0.47	Shell dissolution	↑	−0.8 (Ωarag 0.47)	[54]
		8.2, 7.4
Nucella lamellosa (snail)	6 d	385, 785, 1200, 1585 ppm	Shell weight	↓	−0.18 (785 ppm)	[50]
		7.98, 7.80, 7.54	Shell dissolution	↑	−0.18 (785 ppm)
Osilinus turbinata (snail)	ecosystem	304–20812 µatm	Abundance	↓	−0.7	[46]
		8.17–6.57
Patella caerulea (snail)	ecosystem	304–20812 µatm	Abundance	↓	−0.7	[46]
		8.17–6.57
Patella vulgata (limpet)	5 d	419, 2804 µatm 8.2, 7.6	Metabolic rate	=		[155]
			Protein content	=
			Feeding rate	=
			Radula structure	↓	−0.6 (2,804 µatm)
			pHe	=
			PeCO2	↑	−0.6 (2,804 µatm)
			HCO3−	↑	−0.6 (2,804 µatm)
			Ca2+	↑	−0.6 (2,804 µatm)
			Mg2+	=
Strombus alatus (conch)	60 d	409, 606, 903, 2856 ppm	Calcification	↓	−0.67 (2,856 ppm)	[48]
		8.09, 8.00, 7.86, 7.42
Strombus lubuanus (conch)	6 mo	360, 560 ppm 7.94, 7.90	Survival	↓	−0.04 (560 ppm)	[44]
			Shell growth	↓	−0.04 (560 ppm)
			Shell weight	↓	−0.04 (560 ppm)
Urosalpinx cinerea (whelk)	60 d	409, 606, 903, 2856 ppm	Calcification	↓	−0.09 (606 ppm)	[48]
		8.09, 8.00, 7.86, 7.42
Range of gastropods		336–5148 ppm	Settlement	↓	−0.4	[126]
		8.09–7.08
CEPHALOPODS
Dosidicus gigas (squid)	8–12 h	300, 1000 ppm				[136]
		7.93, 7.62	Metabolic rate	↓	−0.31 (1,000 ppm)
		+Temp. 10, 20, 25 °C	Activity level	↓	−0.31 (1,000 ppm)
		+ PO2 21, 1%
Sepia officinalis (cuttlefish)	48 h	493, 5922 ppm 8.12, 7.10	pHe	↓	−1.02 (5,922 ppm)	[71]
			pHi	=
			PeO2	=
			PeCO2	↑	−1.02 (5,922 ppm)
			HCO3−	↑	−1.02 (5,922 ppm)
	42 d	628, 4271, 6068 ppm 8.01, 7.23, 7.10	Calcification	=		[67]
			Growth	=
			Metabolic rate	=
	42 d	632, 6070 ppm	Calcification	↑	−1.0 (6,070 ppm)	[68]
		8.10, 7.10

Bivalves: 37 studies, 20 species (+1 community); Gastropods: 15 studies, 15 species (+1 community); Cephalopods: 4 studies, 2 species. h = hours, d = days, mo = months; control CO₂/pH listed in italics; ^* denotes preindustrial CO₂ level; denotes parabolic response.