| Contributors | Affiliation | Role |
|---|---|---|
| Waldbusser, George G. | Oregon State University (OSU-CEOAS) | Principal Investigator |
| Hales, Burke | Oregon State University (OSU-CEOAS) | Co-Principal Investigator |
| Haley, Brian | Oregon State University (OSU-CEOAS) | Co-Principal Investigator |
| Langdon, Christopher | Oregon State University (OSU-HMSC) | Co-Principal Investigator |
| Rauch, Shannon | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Initiation of feeding
Impacts of water treatments on development of larval particle feeding mechanisms were determined by measuring the proportion of mussel larvae from each treatment that ingested fluorescent beads at 44 h post-fertilization (initiation of feeding, IF). Preliminary experiments demonstrated that at 44 h after fertilization >50% of M. californianus larvae began feeding when reared at ambient PCO2 (~380 ppm) and 18C.
We expanded upon previous IF findings and determine the length of the delay of the onset of feeding and how this delay affected the modeled growth of larvae to 260 um in shell length, the size at which larvae typically develop into pediveligers. We quantified the delay by first determining the relationship between the proportion of larvae feeding under optimal conditions and time since fertilization. This relationship was best described by the following three parameter logistic equations:
% Feeding= 94.1/((1+Exp (-0.74 × (h-45.1))))
where h is the hour post-fertilization. The logistic equation was then rearranged and linearized, enabling us to estimate the functional age of larvae feeding in each ocean acidification (OA) treatment, by comparison with the proportion of larvae feeding under normal conditions.
Particle processing
To assess the effects of OA on particle processing, 48 h old larvae from each treatment were stocked in nine 25 ml VOA vials (10 larvae/ml) containing the same water treatment in which they developed from fertilized eggs. After an acclimation period of one hour, larvae were then exposed to 2 um Fluorescbrite Polychromatic (Polysciences Inc., Warrington, PA) yellow (Y) beads (excitation maxima of 441 nm and emission maxima at 485 nm) at a concentration of 20 beads/ul and allowed to feed on these beads for one hour. A second and equal dose of 2 um red (R) beads (excitation maxima of 491 nm and 512 nm and emission maxima at 554 nm) were added to the vials at a concentration of 20 beads/ul following the hour-long exposure to Y beads. Triplicate vials were assigned to one of three exposure groups (10, 30, and 50 min) after red beads were added to the vials. To terminate feeding activity at the prescribed exposure time and preserve larvae for later analysis, 40 ul (0.2% v/v) of 10% buffered formalin (pH = 8.1-8.2) were added to vials. Later, larvae were crushed under a cover slip to flatten gut contents and allow better enumeration of all ingested beads in larvae under an epifluorescent microscope (objective 20x; Leica DM 1000). Larval sample sizes consisted of greater than or equal to 20 larvae per replicate vial per treatment.
Gut fullness
Gut fullness was defined as the mean total number of ingested beads (Y+R beads) per larva over 10, 30, and 50 min sampling periods.
Ingestion rate
Ingestion rates were estimated by determining the uptake of R beads after the first 10 min of exposure to this bead type. We then doubled the number of ingested beads as larvae were found to consume R and Y beads at equal rates in preliminary experiments.
Standardizing particle processing for shell-length effects
We examined the relationship between larval shell length (SL), gut fullness, and ingestion rate from a subset of treatments spanning the range of experimental omega-aragonite categories (greater than or equal to 10 larvae from 10 different VOA vials). Shell lengths, defined as the longest axis parallel to the shell hinge, were obtained by photographing larvae under a light microscope (50x) and measuring shell lengths using Image-pro (v.7).
After finding a significant relationship between larval shell size and feeding metrics, we applied the following hyperbolic function from Waldbusser et al. (2015), which strongly predicted the shell lengths of these larvae from the omeaga-aragonite for the first 48 h of development, to estimate shell lengths of larvae for all treatments:
SL=(884.378 × OM_ar )/(1+7.691 × OM_ar )
Next, we divided gut fullness values and ingestion rates of each treatment by their shell length estimate using the above equation. We then reexamined the effects of carbonate chemistry parameters on these feeding metrics after accounting for shell length.
BCO-DMO Processing:
- replaced "M. Californianus" with full species name;
- modified parameter names to conform with BCO-DMO naming conventions;
- copied means into corresponding rows (where applicable);
- rounded to 3 decimal places (per dataset contact);
- replaced "Control (T9)" with "Control_T9";
- 07 Feb 2017: replaced the original version (dated 20-Oct-2016) with the revised version received 16-Nov-2016.
| File |
|---|
OA_feeding_phys.csv (Comma Separated Values (.csv), 6.94 KB) MD5:b85a2daa7e4c2e13f2de93e319c9c790 Primary data file for dataset ID 662154 |
| Parameter | Description | Units |
| species | Species name | unitless |
| treatment | Treatment identifier | unitless |
| pCO2_category | Partial Pressure of CO2 Category | unitless |
| aragonite_sat_category | Aragonite Saturation State Category | unitless |
| replicate | Replicate number | unitless |
| n_evaluated | N (larvae evaluated) | unitless |
| pCO2 | Partial Pressure of CO2 | microatmospheres (uatm) |
| aragonite_sat | Aragonite Saturation State | dimensionless |
| pH | pH (total scale) | pH scale units |
| pcnt_feeding_init | Initiation of feeding (% feeding) | percent (%) |
| pcnt_feeding_init_mean | Mean (of 3 replicates) of initiation of feeding (% feeding) | percent (%) |
| red_beads_mean | Mean red beads (beads/larva) | number per larva |
| yellow_beads_mean | Mean yellow beads (beads/larva) | number per larva |
| gut_fullness | Gut fullness (total beads/larva) | total number per larva |
| gut_fullness_mean | Mean (of 3 replicates) of gut fullness (total beads/larva) | total number per larva |
| size_est | Size estimate | micrometers (um) |
| ingest_rate_hrly | Hourly ingestion rate (beads/larva/hr) | number of beads per larva per hour |
| ingest_rate_hrly_mean | Mean (of 3 replicates) hourly ingestion rates (beads/larva/hr) | number of beads per larva per hour |
| size_std_ingestion_rates | Size standardized ingestion rates (beads/larva/hr/?m) | number of beads per larva per hour per micrometer |
| size_std_gut_fullness | Size-standardized gut fullness (total beads/larva/?m) | total number of beads per larva per micrometer |
| Dataset-specific Instrument Name | epifluorescent microscope |
| Generic Instrument Name | Fluorescence Microscope |
| Dataset-specific Description | Larvae were crushed under a cover slip to flatten gut contents and allow better enumeration of all ingested beads in larvae under an epifluorescent microscope (objective 20x; Leica DM 1000). |
| Generic Instrument Description | Instruments that generate enlarged images of samples using the phenomena of fluorescence and phosphorescence instead of, or in addition to, reflection and absorption of visible light. Includes conventional and inverted instruments. |
| Website | |
| Platform | OSU-HMSC |
| Start Date | 2013-08-19 |
| Description | Laboratory experiments on California mussel larvae (Mytilus californianus) were conducted in the Hatfield Marine Science Center, Newport, OR. |
Extracted from the NSF award abstract:
The shift in the carbonate chemistry of marine waters, as a result of direct anthropogenic CO2 addition and climate-driven changes in circulation, poses a threat to many organisms. A rapidly expanding body of literature has shown that increasing levels of carbonic acid and decreasing carbonate ion levels will have deleterious effects on many marine organisms; however little is known about the mode of action of these changes in water chemistry on marine bivalves. Many marine organisms, particularly bivalves, depend critically on the production of calcium carbonate mineral, and this material becomes thermodynamically unstable under more acidic conditions. The actual mineral precipitation, however, takes place within interstitial volumes intermittently separated from ambient seawater by biological membranes. Therefore, abiotic relationships between solid phase minerals and seawater thermodynamics are oversimplified representations of the complex interplay among seawater chemistry, bivalve physiology, and shell growth processes.
In this integrative, multi-disciplinary project we will develop and apply novel experimental approaches to elucidate fundamental physiological responses to changes in seawater chemistry associated with ocean acidification. The four primary objectives of this project are to: 1) develop a novel experimental approach and system capable of unique combinations of pCO2, pH, and mineral saturation state (Ω), 2) conduct short-term exploratory experiments to determine bivalve responses to different carbonate system variables, 3) conduct longer-term directed studies of the integrated effects of different carbonate system variables over early life history of bivalves, and 4) compare these biological responses among a group of bivalve species that differ in shell mineralogy and nativity to the periodically acidified upwelling region of the Pacific Northwest coast of North America. By isolating the effects of different components of the carbonate system on the early life stages of marine bivalves, e.g. does an oyster larvae respond more strongly to pCO2 or mineral saturation state?, we can begin to identify the mechanisms behind bivalve responses as well as understand how these organisms survive in transiently corrosive conditions.
Laboratory based experiments on three primary taxa (oyster, mussel, clam) having native and non-native species pairs to Oregon’s coastal waters: oysters Ostrea lurida and Crassostrea gigas; mussels Mytilus califonianus and Mytilus galloprovincialis; and clams Macoma nasuta and Ruditapes philippinarum, will allow for species comparisons among different shell mineralogy, microstructure, life-history, and adaptability. High-precision pCO2 and dissolved inorganic carbon (DIC) instruments will be used in experiments to control and properly constrain the carbonate chemistry. A compliment of response variables will be measured across the early life stages of these species that include tissue acid-base balance, shell mineralogy and chemistry, respiration rate, and behavior. Additionally, our emphasis will be placed on observation of development, growth, and shell structure by directly linking observational data with other measured response data. An adaptive strategy using short-term experiments to determine the most salient variables in the carbonate system to manipulate in longer-term studies is being employed. This approach allows us to evaluate acute effects, mimicking diurnal changes to carbonate variables often found in coastal areas, and integrated chronic effects mimicking a more gradual acidification due to the rise in atmospheric CO2.
NSF Climate Research Investment (CRI) activities that were initiated in 2010 are now included under Science, Engineering and Education for Sustainability NSF-Wide Investment (SEES). SEES is a portfolio of activities that highlights NSF's unique role in helping society address the challenge(s) of achieving sustainability. Detailed information about the SEES program is available from NSF (https://www.nsf.gov/funding/pgm_summ.jsp?pims_id=504707).
In recognition of the need for basic research concerning the nature, extent and impact of ocean acidification on oceanic environments in the past, present and future, the goal of the SEES: OA program is to understand (a) the chemistry and physical chemistry of ocean acidification; (b) how ocean acidification interacts with processes at the organismal level; and (c) how the earth system history informs our understanding of the effects of ocean acidification on the present day and future ocean.
Solicitations issued under this program:
NSF 10-530, FY 2010-FY2011
NSF 12-500, FY 2012
NSF 12-600, FY 2013
NSF 13-586, FY 2014
NSF 13-586 was the final solicitation that will be released for this program.
PI Meetings:
1st U.S. Ocean Acidification PI Meeting(March 22-24, 2011, Woods Hole, MA)
2nd U.S. Ocean Acidification PI Meeting(Sept. 18-20, 2013, Washington, DC)
3rd U.S. Ocean Acidification PI Meeting (June 9-11, 2015, Woods Hole, MA – Tentative)
NSF media releases for the Ocean Acidification Program:
Press Release 10-186 NSF Awards Grants to Study Effects of Ocean Acidification
Discovery Blue Mussels "Hang On" Along Rocky Shores: For How Long?
Press Release 13-102 World Oceans Month Brings Mixed News for Oysters
| Funding Source | Award |
|---|---|
| NSF Division of Ocean Sciences (NSF OCE) |