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Award Detail

Doing Business As Name:University of Massachusetts Boston
  • Robyn E Hannigan
  • (315) 268-6400
  • Michael F Tlusty
  • Andrew L Rhyne
Award Date:07/10/2012
Estimated Total Award Amount: $ 204,556
Funds Obligated to Date: $ 204,556
  • FY 2012=$204,556
Start Date:08/15/2012
End Date:07/31/2015
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.074
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Ocean Acidification: Effects on Morphology and Mineralogy in Otoliths of Larval Reef Fish
Federal Award ID Number:1220480
DUNS ID:808008122
Parent DUNS ID:079520631
Program:CRI-Ocean Acidification
Program Officer:
  • Irwin Forseth
  • (703) 292-7862

Awardee Location

Street:100 Morrissey Boulevard
Awardee Cong. District:08

Primary Place of Performance

Organization Name:University of Massachusetts Boston
Cong. District:08

Abstract at Time of Award

If a larval fish cannot avoid predators and cannot orient itself in three-dimensional space, the consequences to the individual and the population are dramatic. Otoliths (ear stones), formed precipitation of calcium carbonate from a bicarbonate-rich and alkaline pH fluid, are critical to fish movement and orientation. Although marine fish compensate for carbon dioxide levels in the surrounding waters little is known about how increased dissolved carbon dioxide and changes in bicarbonate concentrations will impact the formation of otoliths. Increasing atmospheric carbon dioxide concentrations, leading to decreased ocean pH (ocean acidification) may have profound impact on the deposition, growth and function of these critical structures, particularly in larval fish. Focusing on pre-settlement age larval reef fish (Amphiprion clarkii and Chrysiptera parasema), this research integrates expertise in carbonate mineralogy, otolith development, and reef fish biology and leverages this unique combination of expertise to answer fundamental questions regarding the impact of ocean acidification on the structure and function of otoliths. Specifically, the research will answer two fundamental questions: What are the natural morphological and mineralogical variations within growing otoliths? How do these change when larvae are exposed to high dissolved carbon dioxide concentrations? Larvae will be hatched and reared under high carbon dioxide-induced low pH and three types of otoliths (sagittae, lapilli, asterisci) will be extracted over the duration of the experiments. Changes in calcium carbonate mineralogy from aragonite (most common) to vaterite (less common, less dense) as well as changes in crystal habit (well formed to poorly formed) will be evaluated using a combination of microscopic and morphometric techniques. The gap in understanding of otolith morphology and mineralogy precludes our ability to accurately evaluate the impact of ocean acidification on larval fish survival. Given that we know very little about the morphology and mineralogy of all three otolith types in larval marine fish, this research will provide fundamental data regarding natural variability. Data from unexposed and exposed larvae will inform our understanding of the development of otoliths and structure-function relationships. Additionally, otoliths provide long-term records of environmental life histories that could be better exploited if we understood the relation between environmental conditions and otolith morphology and mineralogy. This research represents a unique interdisciplinary collaboration between faculty and students at the University of Massachusetts Boston (a minority-serving institution), New England Aquarium (NEAq; not-for-profit research aquarium), and, through a formal partnership with NEAq, Roger Williams University (primarily undergraduate institution). NEAq is one of the premier visitor attractions in Boston, with over 1.3 million visitors a year, and a major public education resource. In addition to significant research outcomes this project also supports the development of informal science education materials that will be distributed to the public and displayed at the NEAq Harborside Learning Lab and NEAq Ocean Center. The project also supports the training of 1 PhD student and 1 undergraduate student.

Publications Produced as a Result of this Research

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Wilcox?Freeburg, E., Rhyne, A., Robinson, W. E., Tlusty, M., Bourque, B., & Hannigan, R. E. "A comparison of two pH?stat carbon dioxide dosing systems for ocean acidification experiments" Limnology and Oceanography: Methods, v.11, 2013, p.485. doi:10.4319/lom.2013.11.485 

Robert Holmberg, Eric Wilcox-Freeburg "Ocean acidification alters morphology of all otolith types in Clark?s anemonefish (Amphiprion clarkii)" PeerJ preprints, v., 2018, p.. Citation details  

Holmberg, Robert J. and Wilcox-Freeburg, Eric and Rhyne, Andrew L. and Tlusty, Michael F. and Stebbins, Alan and Nye Jr., Steven W. and Honig, Aaron and Johnston, Amy E. and San Antonio, Christine M. and Bourque, Bradford and Hannigan, Robyn E. "Ocean acidification alters morphology of all otolith types in Clark?s anemonefish ( Amphiprion clarkii )" PeerJ, v.7, 2019, p.. doi:10.7717/peerj.6152 Citation details  

Wilcox Freeburg, E., Rhyne, A., Robinson, W.E., Tlusty, M., Bourque, B., Hannigan, R.E. "A comparison of two systems for dosing carbon dioxide into marine aquaria" Limnology and Oceanography: Methods, v.11, 2013, p.485. doi:1541-5856 

Project Outcomes Report


This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

If a larval fish cannot avoid predators and cannot orient itself in three-dimensional space, the consequences to the individual and the population are dramatic. This research focused on a system critcal to the survival of larval fish - the ear (otoconia).  Specificall we studied the impact of ocean acidification on otoliths (ear stones).  Otoliths (2 pairs, 3 on each side) are formed by precipitation of calcium carbonate from a bicarbonate-rich and alkaline pH fluid.  They are critical to fish movement and orientation. Prior to this research the impact of ocean acidification on fish was thought to be minimal since fish can compensate for carbon dioxide levels in the surrounding waters.  We tested that supposition and discovered that the opposite is in fact the case, at least in larvae.  Focusing on pre-settlement age larval reef fish (think infant Nemo) we explored how ocean acidification impacts all 6 of the otoliths with tested impacts ranging from simple changes in circularity and length to changes in crystal shape and mineral composition.  We found that for the largest otolith, the sagittal otolith, in 3 species of reef fish (2 from the same genus of clownfish) the mineral habit (shape) was larger in fish reared at lower pH with significant differences in the core of these otoliths.  We also found that the shape of the lapilli, the otoliths critical to movement and balance, with the circularity of these otoliths increased with decreasing pH.  The shape of the otolith directly impacts its interaction with the hair cells of the otoconia with circular otoliths having less surface area available for interactions.  This likely negatively impacts the function of these otoliths and so may translate to loss of avoidance and swimming capabilities.  In the grunts we found even more extrreme impacts with the lapilli also showing increased ciruclarity with decreased pH.  In some otoliths from fish reared at low pH the changes in crystal habitat were profound with significant twinning leading to protuberances, sometimes rendering the otolith non-functional.  In the sagittae of grunts we also found, as we did in clownfish, that changes in crystal habit was accompanied by changes in mineral polymorph with otoliths from low pH treatements containing amorphous calcium carbonate, vaterite, and hexagonal aragonite.  These forms of calcium carbonate are less stable than the preferred pristmatic aragonite and less dense as well.  Density of the otolith is critical to maintaining contact with the macular hair cells.  Lower density also translates to loss of function.  Our results demonstrate that the impacts of ocean acidification on the earliest life stages of fish are significant and could have profound consequences for survival.

Last Modified: 11/15/2015
Modified by: Robyn E Hannigan

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