http://lod.bco-dmo.org/id/dataset/662188
eng; USA
utf8
dataset
Highest level of data collection, from a common set of sensors or instrumentation, usually within the same research project
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
2016-10-20
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
Results of modeled growth of Mytilus californianus larvae to pediveliger stage after acute acidification stress
2016-10-20
publication
2016-10-20
revision
BCO-DMO Linked Data URI
2016-10-20
creation
http://lod.bco-dmo.org/id/dataset/662188
George G. Waldbusser
Oregon State University
principalInvestigator
Burke Hales
Oregon State University
principalInvestigator
Brian Haley
Oregon State University
principalInvestigator
Christopher Langdon
Oregon State University
principalInvestigator
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
publisher
Cite this dataset as: Waldbusser, G. G., Langdon, C., Hales, B., Haley, B. (2016) Results of modeled growth of Mytilus californianus larvae to pediveliger stage after acute acidification stress. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 20 October 2016) Version Date 2016-10-20 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/662188 [access date]
Modeled growth of Mytilus californianus larvae to pediveliger stage after acute acidification stress Dataset Description: Methods and Sampling: <p><strong>Initiation of feeding</strong><br />
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 &gt;50% of&nbsp;<em>M. californianus</em>&nbsp;larvae began feeding when reared at ambient PCO2 (~380 ppm) and 18C.</p>
<p>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:</p>
<p>% Feeding= &nbsp;94.1/((1+Exp (-0.74 × (h-45.1))))&nbsp;</p>
<p>where&nbsp;<em>h</em>&nbsp;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.</p>
<p><strong>Particle processing</strong><br />
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&nbsp;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&nbsp;20 larvae per replicate vial per treatment.</p>
<p><strong>Gut fullness&nbsp;</strong><br />
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.&nbsp;</p>
<p><strong>Ingestion rate</strong><br />
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.</p>
<p><strong>Standardizing particle processing for shell-length effects</strong><br />
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&nbsp;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).&nbsp;</p>
<p>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:</p>
<p>SL=(884.378 × OM_ar )/(1+7.691 × OM_ar )</p>
<p>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.</p>
<p><strong>Modeled effects of initial 48 h OA exposure on subsequent larval energy budgets, growth and development</strong><br />
To estimate the effects of exposure to OA treatments during the first 48 h of larval development on subsequent energy budgets of M. californianus larvae, we first estimated energy contents of larvae in treatments at 44 h post-fertilization by applying the relationship between estimated total body energy content (E_SL; uJoules) and larval shell size reported for Mytilus edulis larvae by Sprung (1984a):</p>
<p>E_SL = 2.28 × (10^-7) × (SL^3.12)</p>
<p>where SL is the shell length (um). To our knowledge, this is the only known allometric relationship between energy content and shell length for any larval Mytilus species. Additionally, the relationship provided by Sprung (1984a) seemed appropriate to use here as M. edulis and M. californianus are similar with respect to egg size and, presumably, energy content (Strathmann 1987).&nbsp;</p>
<p>The total energy contents of larvae (ET) at 48 h post-fertilization (i.e. after a 4 h period during which larvae could be feeding on algal cells) were then estimated to evaluate the energy budgets of larvae among OA treatments. &nbsp;ET was estimated by accounting for ESL and other potential energy gains and losses using the following equation:&nbsp;</p>
<p>ET = ESL + ((I×AE)/h &nbsp;× (4-D)) - R</p>
<p>where I is the ingestion rate (uJoules/h), AE is the assimilation efficiency (%) that describes the conversion of ingested food to energy available to larvae, R is the energy loss due to respiration (uJoules) over the 4 h period, and D is the energy gain or loss (uJoules) to ET as a result of developmental advancement or delay in feeding activity. Physiological rate processes were converted to energy units under the following assumptions: 1) growth or change in ESL was negligible between initiation of feeding experiments (44 h) and when the sizes of larvae were measured at 48 h; 2) larval ingestion rates were constant over the period from 44 to 48 h and were equivalent to algal ingestion rates with an estimated algal cell energetic content of 0.61 uJoules/cell (Isochrysis galbana, Sprung 1984a), which was also the food source underpinning the relationship between energy content and shell length; 3) total time for potential gains from ingestion was 4 h +/-&nbsp;any advancement/delay in the initiation of feeding among early larvae; 4) assimilation efficiencies of larvae were 0.38 (Sprung 1982); 5) respiration rates were similar among larvae in all treatments except for those of larvae in the lowest pH treatment (based on Waldbusser et al. 2015); &nbsp;and 6) 1 nl O2 was equivalent to 20.1 uJoule of respired energy (Crisp 1971).&nbsp;</p>
<p>To estimate the impacts of OA during the first 48 h of development on subsequent larval growth, we modeled the developmental time of larvae to reach a shell length of 260 um, the approximate size of pediveliger mussel larvae under normal conditions (Sprung 1984a) and a proxy for larval competency for settlement and metamorphosis; however, we note that larval competency is frequently correlated with but not necessarily dependent on larval size (Coon et al. 1990, Pechenik et al. 1996). To make these extrapolations, we first estimated energy content gains of larvae in 24 h intervals (delta&nbsp;E) using the following equation:</p>
<p>delta E= ESL + (I × AE × NGE)</p>
<p>where ESL is the estimated energy content of the larvae based on their shell length at 48 post-fertilization, I is the ingestion rate (uJoules/h), AE is the assimilation efficiency (%), NGE is the net growth efficiency (%). &nbsp;ESL and I in this study were assumed constant between 48 and 72 h post-fertilization. After this initial 24 h period (i.e. 48-72 h post-fertilization), modeled gains in larval energy content were added to those of larvae of each treatment and larval shell lengths were adjusted by rearranging equation 2. From 72 h post-fertilization onward, we modified larval ingestion rates and larval respiration rates in accordance with allometric equations for M. edulis as described by Sprung (1984b, c). This model explicitly tests how an acute initial 48 h OA exposure could significantly alter the subsequent duration and energy budgets of mussel larvae. Assimilation efficiencies were 0.38, 0.29, and 0.27 for larvae &lt; 200 um, between 200-250 um, and &gt;&nbsp;250 um, respectively (Bayne 1983). NGE were also adjusted for changes in larval size and estimated at 0.78, 0.67, 0.65 for larva &lt; 200 um, between 200-250 um, and &gt;&nbsp;250 um (Bayne 1983). The impacts of differences in initiation of feeding, initial feeding rates and shell size after 48 h of development on subsequent larval growth to 260 um were estimated by non-linear multiple regression analysis.</p>
Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-1041267 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=1041267
completed
George G. Waldbusser
Oregon State University
541-737-8964
Oregon State University 104 COAS Admin. Bldg.,
Corvallis
OR
97331
USA
waldbuss@coas.oregonstate.edu
pointOfContact
Burke Hales
Oregon State University
(541) 737-8121
College of Earth, Ocean, and Atmospheric Sciences (CEOAS) Oregon State University 104 COAS Admin. Bldg.
Corvallis
OR
97331-5503
USA
bhales@coas.oregonstate.edu
pointOfContact
Brian Haley
Oregon State University
541-737-2649
Oregon State University 104 COAS Admin. Bldg.,
Corvallis
OR
97331-5503
USA
brian.haley@oregonstate.edu
pointOfContact
Christopher Langdon
Oregon State University
305.421.4614
University of Miami 4600 Rickenbacker Causeway
Miami
FL
33149
USA
clangdon@rsmas.miami.edu
pointOfContact
asNeeded
Dataset Version: 20 October 2016
Unknown
species
treatment
pCO2
aragonite_sat
pH
pH_category
omega_category
development_time_post_fert
time
shell_size_est
energy_est_from_shell_len
ingestion_rate_est
food_energy_content
assimilation_efficiency
resp_rate
resp_cost
energy_est_from_shell_len2
daily_ingestion_rate
net_growth_efficiency
respiration_costs
change_in_energy
scope_for_growth_energy
delay_effect
theme
None, User defined
species scientific name (binomial)
treatment
Partial pressure of CO2
Aragonite Saturation State
pH
No BCO-DMO term
time of day
featureType
BCO-DMO Standard Parameters
Waldbusser_HMSC
service
Deployment Activity
Hatfield Marine Science Center, Newport, OR
place
Locations
otherRestrictions
otherRestrictions
Access Constraints: none. Use Constraints: Please follow guidelines at: http://www.bco-dmo.org/terms-use Distribution liability: Under no circumstances shall BCO-DMO be liable for any direct, incidental, special, consequential, indirect, or punitive damages that result from the use of, or the inability to use, the materials in this data submission. If you are dissatisfied with any materials in this data submission your sole and exclusive remedy is to discontinue use.
Science, Engineering and Education for Sustainability NSF-Wide Investment (SEES): Ocean Acidification (formerly CRI-OA)
https://www.nsf.gov/funding/pgm_summ.jsp?pims_id=503477
Science, Engineering and Education for Sustainability NSF-Wide Investment (SEES): Ocean Acidification (formerly CRI-OA)
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?
Discovery nsf.gov - National Science Foundation (NSF) Discoveries - Trouble in Paradise: Ocean Acidification This Way Comes - US National Science Foundation (NSF)
Press Release 12-179 nsf.gov - National Science Foundation (NSF) News - Ocean Acidification: Finding New Answers Through National Science Foundation Research Grants - US National Science Foundation (NSF)
Press Release 13-102 World Oceans Month Brings Mixed News for Oysters
Press Release 13-108 nsf.gov - National Science Foundation (NSF) News - Natural Underwater Springs Show How Coral Reefs Respond to Ocean Acidification - US National Science Foundation (NSF)
Press Release 13-148 Ocean acidification: Making new discoveries through National Science Foundation research grants
Press Release 13-148 - Video nsf.gov - News - Video - NSF Ocean Sciences Division Director David Conover answers questions about ocean acidification. - US National Science Foundation (NSF)
Press Release 14-010 nsf.gov - National Science Foundation (NSF) News - Palau's coral reefs surprisingly resistant to ocean acidification - US National Science Foundation (NSF)
Press Release 14-116 nsf.gov - National Science Foundation (NSF) News - Ocean Acidification: NSF awards $11.4 million in new grants to study effects on marine ecosystems - US National Science Foundation (NSF)
SEES-OA
largerWorkCitation
program
A mechanistic understanding of the impacts of ocean acidification on the early life stages of marine bivalves
https://osprey.bco-dmo.org/project/2167
A mechanistic understanding of the impacts of ocean acidification on the early life stages of marine bivalves
<p><em>Extracted from the NSF award abstract:</em></p>
<p>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.</p>
<p>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.</p>
<p>Laboratory based experiments on three primary taxa (oyster, mussel, clam) having native and non-native species pairs to Oregon’s coastal waters: oysters <em>Ostrea lurida </em>and <em>Crassostrea gigas</em>; mussels <em>Mytilus califonianus</em> and <em>Mytilus galloprovincialis</em>; and clams <em>Macoma nasuta</em> and <em>Ruditapes philippinarum</em>, 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.</p>
Mechanisms of bivalve response to acidification
largerWorkCitation
project
eng; USA
oceans
Hatfield Marine Science Center, Newport, OR
2016-10-20
Coastal and estuarine waters of Oregon, U.S.A.
0
BCO-DMO catalogue of parameters from Results of modeled growth of Mytilus californianus larvae to pediveliger stage after acute acidification stress
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
http://lod.bco-dmo.org/id/dataset-parameter/662199.rdf
Name: species
Units: unitless
Description: <p>Species name</p>
http://lod.bco-dmo.org/id/dataset-parameter/662200.rdf
Name: treatment
Units: unitless
Description: <p>Treatment identifier</p>
http://lod.bco-dmo.org/id/dataset-parameter/662201.rdf
Name: pCO2
Units: microatmospheres (uatm)
Description: <p>Partial pressure of CO2</p>
http://lod.bco-dmo.org/id/dataset-parameter/662202.rdf
Name: aragonite_sat
Units: dimensionless
Description: <p>Aragonite saturation state</p>
http://lod.bco-dmo.org/id/dataset-parameter/662203.rdf
Name: pH
Units: pH scale units
Description: <p>pH (total scale)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662204.rdf
Name: pH_category
Units: unitless
Description: <p>pH category</p>
http://lod.bco-dmo.org/id/dataset-parameter/662205.rdf
Name: omega_category
Units: unitless
Description: <p>Aragonite saturation state category</p>
http://lod.bco-dmo.org/id/dataset-parameter/662206.rdf
Name: development_time_post_fert
Units: hours
Description: <p>Development time post-fertilization</p>
http://lod.bco-dmo.org/id/dataset-parameter/662207.rdf
Name: time
Units: days
Description: <p>Time</p>
http://lod.bco-dmo.org/id/dataset-parameter/662208.rdf
Name: shell_size_est
Units: micrometers (um)
Description: <p>Shell size estimate</p>
http://lod.bco-dmo.org/id/dataset-parameter/662209.rdf
Name: energy_est_from_shell_len
Units: micro Joules (uJoules)
Description: <p>Energy estimate from shell length</p>
http://lod.bco-dmo.org/id/dataset-parameter/662210.rdf
Name: ingestion_rate_est
Units: number of beads per larva per hour
Description: <p>Ingestion rate estimate (beads/larva/h)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662211.rdf
Name: food_energy_content
Units: micro Joules per cell
Description: <p>Food Energy Content (uJ/cell)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662212.rdf
Name: assimilation_efficiency
Units: unitless
Description: <p>Assimilation effciency (fraction)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662213.rdf
Name: resp_rate
Units: nanoliters O2 per hour
Description: <p>Respiration rate (nl O2/h)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662214.rdf
Name: resp_cost
Units: micro Joules
Description: <p>Respiration Cost (uJoules)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662215.rdf
Name: energy_est_from_shell_len2
Units: micro Joules
Description: <p>Energy estimate from shell length (uJoules)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662216.rdf
Name: daily_ingestion_rate
Units: number of beads per larva per day
Description: <p>Daily ingestion rate (beads/larva/day)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662217.rdf
Name: net_growth_efficiency
Units: unitless
Description: <p>Net growth efficiency (fraction)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662218.rdf
Name: respiration_costs
Units: micro Joules
Description: <p>Respiration costs (uJoules)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662219.rdf
Name: change_in_energy
Units: micro Joules
Description: <p>Change in energy content (uJoules)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662220.rdf
Name: scope_for_growth_energy
Units: micro Joules
Description: <p>Scope for Growth Energy (uJoules)</p>
http://lod.bco-dmo.org/id/dataset-parameter/662221.rdf
Name: delay_effect
Units: micro Joules
Description: <p>Delay Effect (uJoules)</p>
GB/NERC/BODC > British Oceanographic Data Centre, Natural Environment Research Council, United Kingdom
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
65108
https://datadocs.bco-dmo.org/file/m77kmRotjw7L3n/OA_modeled_growth.csv
OA_modeled_growth.csv
Primary data file for dataset ID 662188
download
https://osprey.bco-dmo.org/dataset/662188/data/download
download
onLine
dataset
<p><strong>Initiation of feeding</strong><br />
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 &gt;50% of&nbsp;<em>M. californianus</em>&nbsp;larvae began feeding when reared at ambient PCO2 (~380 ppm) and 18C.</p>
<p>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:</p>
<p>% Feeding= &nbsp;94.1/((1+Exp (-0.74 × (h-45.1))))&nbsp;</p>
<p>where&nbsp;<em>h</em>&nbsp;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.</p>
<p><strong>Particle processing</strong><br />
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&nbsp;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&nbsp;20 larvae per replicate vial per treatment.</p>
<p><strong>Gut fullness&nbsp;</strong><br />
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.&nbsp;</p>
<p><strong>Ingestion rate</strong><br />
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.</p>
<p><strong>Standardizing particle processing for shell-length effects</strong><br />
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&nbsp;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).&nbsp;</p>
<p>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:</p>
<p>SL=(884.378 × OM_ar )/(1+7.691 × OM_ar )</p>
<p>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.</p>
<p><strong>Modeled effects of initial 48 h OA exposure on subsequent larval energy budgets, growth and development</strong><br />
To estimate the effects of exposure to OA treatments during the first 48 h of larval development on subsequent energy budgets of M. californianus larvae, we first estimated energy contents of larvae in treatments at 44 h post-fertilization by applying the relationship between estimated total body energy content (E_SL; uJoules) and larval shell size reported for Mytilus edulis larvae by Sprung (1984a):</p>
<p>E_SL = 2.28 × (10^-7) × (SL^3.12)</p>
<p>where SL is the shell length (um). To our knowledge, this is the only known allometric relationship between energy content and shell length for any larval Mytilus species. Additionally, the relationship provided by Sprung (1984a) seemed appropriate to use here as M. edulis and M. californianus are similar with respect to egg size and, presumably, energy content (Strathmann 1987).&nbsp;</p>
<p>The total energy contents of larvae (ET) at 48 h post-fertilization (i.e. after a 4 h period during which larvae could be feeding on algal cells) were then estimated to evaluate the energy budgets of larvae among OA treatments. &nbsp;ET was estimated by accounting for ESL and other potential energy gains and losses using the following equation:&nbsp;</p>
<p>ET = ESL + ((I×AE)/h &nbsp;× (4-D)) - R</p>
<p>where I is the ingestion rate (uJoules/h), AE is the assimilation efficiency (%) that describes the conversion of ingested food to energy available to larvae, R is the energy loss due to respiration (uJoules) over the 4 h period, and D is the energy gain or loss (uJoules) to ET as a result of developmental advancement or delay in feeding activity. Physiological rate processes were converted to energy units under the following assumptions: 1) growth or change in ESL was negligible between initiation of feeding experiments (44 h) and when the sizes of larvae were measured at 48 h; 2) larval ingestion rates were constant over the period from 44 to 48 h and were equivalent to algal ingestion rates with an estimated algal cell energetic content of 0.61 uJoules/cell (Isochrysis galbana, Sprung 1984a), which was also the food source underpinning the relationship between energy content and shell length; 3) total time for potential gains from ingestion was 4 h +/-&nbsp;any advancement/delay in the initiation of feeding among early larvae; 4) assimilation efficiencies of larvae were 0.38 (Sprung 1982); 5) respiration rates were similar among larvae in all treatments except for those of larvae in the lowest pH treatment (based on Waldbusser et al. 2015); &nbsp;and 6) 1 nl O2 was equivalent to 20.1 uJoule of respired energy (Crisp 1971).&nbsp;</p>
<p>To estimate the impacts of OA during the first 48 h of development on subsequent larval growth, we modeled the developmental time of larvae to reach a shell length of 260 um, the approximate size of pediveliger mussel larvae under normal conditions (Sprung 1984a) and a proxy for larval competency for settlement and metamorphosis; however, we note that larval competency is frequently correlated with but not necessarily dependent on larval size (Coon et al. 1990, Pechenik et al. 1996). To make these extrapolations, we first estimated energy content gains of larvae in 24 h intervals (delta&nbsp;E) using the following equation:</p>
<p>delta E= ESL + (I × AE × NGE)</p>
<p>where ESL is the estimated energy content of the larvae based on their shell length at 48 post-fertilization, I is the ingestion rate (uJoules/h), AE is the assimilation efficiency (%), NGE is the net growth efficiency (%). &nbsp;ESL and I in this study were assumed constant between 48 and 72 h post-fertilization. After this initial 24 h period (i.e. 48-72 h post-fertilization), modeled gains in larval energy content were added to those of larvae of each treatment and larval shell lengths were adjusted by rearranging equation 2. From 72 h post-fertilization onward, we modified larval ingestion rates and larval respiration rates in accordance with allometric equations for M. edulis as described by Sprung (1984b, c). This model explicitly tests how an acute initial 48 h OA exposure could significantly alter the subsequent duration and energy budgets of mussel larvae. Assimilation efficiencies were 0.38, 0.29, and 0.27 for larvae &lt; 200 um, between 200-250 um, and &gt;&nbsp;250 um, respectively (Bayne 1983). NGE were also adjusted for changes in larval size and estimated at 0.78, 0.67, 0.65 for larva &lt; 200 um, between 200-250 um, and &gt;&nbsp;250 um (Bayne 1983). The impacts of differences in initiation of feeding, initial feeding rates and shell size after 48 h of development on subsequent larval growth to 260 um were estimated by non-linear multiple regression analysis.</p>
Specified by the Principal Investigator(s)
<p>BCO-DMO Processing:<br />
- replaced "M. Californianus" with full species name;<br />
- modified parameter names to conform with BCO-DMO naming conventions;<br />
- rounded to 3 decimal places (per dataset contact);<br />
- replaced blanks with "nd".</p>
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Deployment: Waldbusser_HMSC
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George G. Waldbusser
Oregon State University
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