1. Effects of Ocean Acidification and Warming on the
Development and Survival of Homarus americanus Larvae
Darcia Gonzalez¹´², Sarah Caron¹, Devin Domeyer¹, Jesica Waller¹, David Fields¹
1Bigelow Laboratory for Ocean Sciences, East Boothbay, ME
2 University of Texas Rio Grande Valley, Edinburg, TX
Abstract Methods
Results
Conclusions
The goal of this experiment was to study the carapace length,
mass, survival and overall development of American lobsters
(Homarus americanus) from southern New England under
predicted end-century pCO₂s and temperatures. The American
lobster comprises one of New England’s most valued marine
fisheries, but we do not yet know how changing oceanic
conditions will affect the lobster during its four larval stages. A
series of four measurements were conducted in order to test
the potential interactive effects of higher temperatures and
pCO₂ levels. The parameters that were analyzed included
survival, dry weight, carapace length as well as Carbon and
Nitrogen mass of these larvae. We found that both higher pCO₂
and higher temperatures had no significant effect on the length
and mass of American lobster larvae. This provides indication
that larvae from the southern extent of the lobster’s geographic
range may be resilient to predicted end-century increases in
pCO2 and temperatures.
• Temperature, pH and salinity was measured daily.
• Survival was measured by estimating the percent of larvae alive in
each tank every other day.
• Dry weights were recorded 48 hours after lobster larvae began a new
stage.
• Carapace length was measured using ImageJ, a photo analyzing
software.
• Carbon and Nitrogen were measured at Bigelow Analytical Services.
• Water chemistry was monitored on a weekly basis. Two samples were
obtained from each treatment. One was used for spectrometric pH
measurements while the other was used for total alkalinity.
• Carbonate chemistry was calculated using CO2SYS.
• 3 way ANOVAS were done to analyze the effect of pCO2 and
temperature treatment on carapace length and dry weight.
• These measurements are a portion of a larger experiment where the
respiration rates as well as swimming speeds were also studied.
• Larvae raised at end-century temperatures in all pCO₂ treatments had
slightly decreased survival.
• Overall, our results suggest that rising pCO₂ and temperatures have no
significant effects on the growth and development on H. americanus
larvae.
• A similar study of H. americanus larvae from the mid-coast region found
that increased pCO₂ levels (1200 ppm) reduced the carapace length of
larvae(1) . This provides indication that larvae from the southern extent
of the lobster’s geographic range may be resistant to predicted end-
century increases in pCO2 and temperatures.
Acknowledgments: Support for this project was provided by NSF Grant #1460861 REU Site:
Bigelow Laboratory of Ocean Sciences – Undergraduate Research Experience in the Gulf of
Maine and the World Ocean, Bigelow Analytical Services. Thanks to Craig Burnell and the
University of Maine Darling Marine Center.
Research Question:
Can increases in ocean temperature and rising pCO₂ levels affect
how Homarus americanus larvae develop?
Figure 4. Results showing carapace length averages by stage for each treatment with standard deviation.
Figure 3. Results showing average dry weights of lobster larvae per stage for each treatment with
standard deviation.
Figure 5. a) Preliminary graph providing a slope based off of observed data points on larval survival (this graph
is an example of just one treatment consisting of duplicated tanks). b.) Final graph showing logarithmic
survival slopes for each treatment.
Table 2. Water chemistry over the experimental period. Both pH and alkalinity
were measured on the total scale.
Table 1. Experimental design shows 4 tanks for each treatment for a total of 12 tanks. This was
replicated giving a total of 24 tanks.
Figure 1. a) Global ocean surface pH.
Figure 2. Four different lobster larval stages and their distinct appendages.
IPCC 2013.
References:
1. Keppel, E. A., Scrosati, R. A., & Courtenay, S. C. (2012). Ocean acidification decreases growth and
development in American lobster (Homarus americanus) larvae. J. Northw. Atl. Fish. Sci, 44, 61-66.
2. IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth
Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge, UK and New York, NY, USA.
3. Fogarty, M. J. (1983). Distribution and relative abundance of American lobster, Homarus americanus, larvae:
a review. NOAA technical report NMFS SSRF United States. National Marine Fisheries Service.
16°C 19°C
PCO2 Input (ppm) 400 750 1200 400 750 1200
Temperature (°C) 16.3 ± 0.12 16.6 ± 0.21 16.5 ± 0.23 19.2 ± 0.40 18.3 ± 0.12 18.5 ± 0.40
Salinity 34.7 ± 0.58 34 ± 1 34.7 ± 0.58 35 ± 0 34.3 ± 0.58 35 ± 0
pHT 8.17 ± 0.15 8.01 ± 0.01 7.86 ± 0.03 8.18 ± 0.07 8.08 ± 0.03 7.91 ± 0.03
AT (µEq kg-1
) 2,172.18 ± 13.57 2,190 ± 42.64 2,108 ± 65.97 2,183 ± 39.07 2,190 ± 36.42 2,180 ± 10.36
PCO2 (ppm) 267 ± 9 405 ± 16 558 ± 41 260 ± 52 338 ± 19 510 ± 36
HCO3
-
(µmol kg-1
) 1,885 ± 11 1,985 ± 42 1,959 ± 64 1,883 ± 16 1,950 ± 30 2,008 ± 2
CO3
2-
(µmol kg-1
) 111 ± 4.6 80 ± 3.6 57 ± 4.1 117 ± 16.8 93 ± 5.6 66 ± 4.8
Ωcal 2.68 ± 0.1 1.94 ± 0.1 1.39 ± 0.1 2.80 ± 0.4 2.25 ± 0.1 1.60 ± 0.1
Ωarag 1.68 ± 0.07 1.22 ± 0.05 0.87 ± 0.06 1.76 ± 0.25 1.41 ± 0.09 1.01 ± 0.07
b.
a.
a.b.
Figure 6. a) Stage 4 Lobster larval carbon mass.
Figure 6. b) Lobster larval nitrogen mass.
b.
a.
b) Conceptual schematic of predicted global
average surface temperature change.
1950 2000 2050 2100
Ocean Acidification and Warming
In order to test if global warming and ocean acidification will
affect the American Lobster, we examined growth and
development across the four distinct larval stages. We used
three different pCO₂ levels as well as two temperatures that the
Intergovernmental Panel on Climate Change (IPCC) has
predicted for the end of century. It is unknown how lobsters will
respond to changes in carbonate chemistry and temperature.
16°C 19°C