jcaracappa1
commented
9 months ago @BBeltz1 Can you add Figure4-GraceSaba_2024.png to this page?
Open BBeltz1 opened 10 months ago
jcaracappa1
commented
9 months ago @BBeltz1 Can you add Figure4-GraceSaba_2024.png to this page?
andybeet
commented
9 months ago
Primary Contact
saba@marine.rutgers.edu
Secondary Contact
No response
Data Name (This will be the displayed title in Catalog)
Ocean Acidification and Other Stressors
Indicator Name (as exists in ecodata)
ocean_acidification
Family (Which group is this indicator associated with?)
Data Description
Maps and variability of regional carbonate chemistry and other oceanographic properties
Introduction to Indicator (Please explain your indicator)
Ocean acidification (OA) has caused measured declines in global ocean pH and is projected to continue declining by up to 0.30 pH units over the course of the 21st century if high carbon dioxide emissions continue (IPCC 2019). OA also changes the availability of minerals required by organisms to form calcified structures such as shells and other structures. Calcifying conditions in seawater can be determined by measuring aragonite saturation state (ΩArag or omega), the tendency of a common type of calcium carbonate, aragonite, to form or dissolve. When ΩArag is less than 1, shells and other calcium carbonate structures begin to dissolve. Typical surface ocean ΩArag is 2-4, but extremes can be <1 or >5. As the ocean absorbs carbon dioxide, both pH and ΩArag decrease and can cause organisms to respond with reduced survival, calcification rates, growth, and reproduction, as well as impaired development, and/or changes in energy allocation (reviewed in @kroeker_impacts_2013, @saba_recommended_2019). However, sensitivity levels vary, and some organisms exhibit negative responses to calcification and other processes when ΩArag is as low as 3.
The U.S. Northeast Shelf (NES) is prone not only to global rates of ocean acidification, but also to coastal processes that can act to exacerbate acidification, including freshwater sources (primarily riverine), eutrophication and photosynthesis‐respiration cycles, coastal upwelling, and other influences (@goldsmith_scientific_2019, @wrightfairbanks_autonomous_2020, @xu_long-term_2020). Often times, other stressors such as ocean warming and/or low bottom water dissolved oxygen can co-occur. Dissolved oxygen concentrations at or below 5 mg/liter is considered problematic for marine life. Although concentrations between 3-5 mg/liter may not be low enough to directly cause death in many marine animals, research focused on marine species has identified other negative impacts such as reduced metabolism, feeding, growth, and reproduction at these levels. Lower hypoxic concentrations of dissolved oxygen (< 3 mg/liter) have been directly associated with mortalities in some organisms in other coastal regions around the world.
Any one stressor may not itself be an issue due to the resiliency of many coastal species to fluctuating natural environmental conditions. However, when more than one stressor occurs simultaneously, an organism may become unable to fully withstand changes. The impacts of multiple stressors occurring simultaneously on organism health is much less well known. The co-occurrence of low dissolved oxygen and pH may exacerbate negative responses in organisms or increase their susceptibility to either or both oxygen and pH.
The spatio-temporal variability of OA in the NES is still poorly described, and as of yet there are no analyses that have determined times or locations where multiple environmental stressors are co-located. The purpose of developing data products for OA and other stressors for the State of the Ecosystems reports is to determine locations and times where potential stressors overlap in space and time to assist in identifying potentially vulnerable species habitats.
Key Results and Visualization
The products developed here include: plots of the seasonal progression (Spring-Fall 2023) of oceanographic properties (including temperature, chlorophyll, dissolved oxygen, pH, and aragonite saturation state) on the New Jersey coastal shelf; plots summarizing a multi-stressor event in the Mid-Atlantic during summer 2023; static and animated maps of summer-time bottom pH and aragonite saturation state on the U.S. Northeast Shelf (2007-2023); and maps of locations where species sensitivity levels for aragonite saturation state were reached in bottom water during the summer (2007-2023).
Seasonal progression in the Mid-Atlantic (2023)
With high temporal resolution (> seasonal) glider sampling off the coast of New Jersey in 2023, we observed the evolution of water column structure from spring stratification to fall breakdown, and the resulting changes in bottom water chemistry (see below section ‘Summer 2023 multi-stressor event in the Mid-Atlantic’). Event-based oceanographic changes were also observed due to upwelling, the passage of Hurricane Lee offshore of the sampling region around 09/16, and a strong hybrid storm (Nor’easter, and Tropical Storm Ophelia) that drove the eventual water column turnover in the fall (09/24-09/26).
Figure 1. Maps of four 2023 glider deployments on the coastal New Jersey shelf and the resulting vertical profiles of oceanographic parameters characterizing the evolution of temperature (in °C), chlorophyll, dissolved oxygen, pH, and aragonite saturation state (Omega) from Spring through Early Fall. Preliminary data presented here are the result of support provided by a grant from the New Jersey Research and Monitoring Initiative (RMI).
Summer 2023 multi-stressor event in the Mid-Atlantic
From August-September 2023, much of the bottom water sampled from Sandy Hook, New Jersey south to Tuckerton, New Jersey and from nearshore (15 meter water depth) to deeper depths (60 meter water depth), exhibited dissolved oxygen concentrations less than 5 mg/L and pH values less than 7.75. Coast-wide, hypoxic levels of dissolved oxygen (concentrations < 3 mg/L) were observed at shallower, more inshore locations. Some of these locations were shallow enough to be observed in glider ru40, but much of these hypoxic levels were observed in a shallow glider (ru28, with a 50 m depth capacity) deployed at the same time. In addition to low pH measured in bottom waters by glider ru39, which is indicative of ocean acidification, aragonite saturation state (Omega) was calculated to be < 1 in several locations. Normal, more optimal levels in seawater typically include dissolved oxygen concentrations > 7 mg/liter, pH of ~8.1, and aragonite saturation states > 3.
During the time when low dissolved oxygen and pH/aragonite saturation state were observed, numerous mortalities of fish, lobsters and crabs within the sampling area were reported. The mortalities were observed in bottom waters primarily off the coast of Monmouth and Ocean Counties and included the Mud Hole, as far east as Lillian wreck, and southward in Sea Girt and Axel Carlson Reefs and the surrounding areas. Mortalities were reported for American lobsters, Jonah crab, Atlantic rock crab, spider crabs, black sea bass, and tautog not only in pots where trapped organisms would not have been able to escape poor conditions, but also on the open bottom. This observation suggests that if low dissolved oxygen and/or pH were indeed the culprit for these reported mortalities, the area may have been extensive enough that they could not escape in time.
Healthy dissolved oxygen, pH, and aragonite saturation state levels were restored in bottom waters temporarily during the offshore passage of Hurricane Lee around 09/16, and for the remainder of the sampling after a strong hybrid storm that started on 09/24 and drove the eventual fall water column turnover on 09/26.
Figure 2. Left: Mission tracks of three gliders (named ru28, ru39, ru40) deployed off the coast of New Jersey in August and September. Gliders ru39 and ru40 were deployed as a pair along the same mission track. All gliders had sensors measuring temperature and salinity. Gliders ru28 and ru40 each had an additional sensor measuring dissolved oxygen (no pH or aragonite saturation state), and glider ru39 had an additional sensor measuring pH (no dissolved oxygen). Right: Locations of hypoxic levels of dissolved oxygen (magenta; < 3 mg/liter) and low aragonite saturation state (cyan; < 1) measured along the glider mission tracks and locations of reported fish, lobster, and/or crab mortalities (red X). Preliminary data presented here are the result of support provided by grants from the New Jersey Research and Monitoring Initiative (RMI) and New Jersey Department of Environmental Protection’s Bureau of Marine Water Monitoring.
Figure 3. Complete cross-sections of dissolved oxygen concentrations (left top and bottom), pH (right top), and aragonite saturation state (omega, right bottom) measured along the associated mission tracks during the deployments of the three gliders (named ru28, ru39, ru40; see tracks in Figure 2) during August and September 2023. Dissolved oxygen concentrations between 3-5 mg/liters are expressed as orange & yellow, and hypoxic concentrations < 3 mg/liter are expressed as red. pH values < 7.75 and omega < 1 are highlighted in cyan. Preliminary data presented here are the result of support provided by grants from the New Jersey Research and Monitoring Initiative (RMI) and New Jersey Department of Environmental Protection’s Bureau of Marine Water Monitoring.
Summer-time bottom pH and aragonite saturation state on the U.S. Northeast Shelf
Using available quality-controlled vessel- and glider-based datasets accompanying observations on the U.S. Northeast Shelf, maps of summer-time (June-August) bottom water pH and aragonite saturation state (omega) were developed for each year from 2007-2023 and combined to create animations of pH and omega over time in the region (pH: access here; omega: access here). The animations depict high variability in time and space and increases in sampling frequency over time. Summer-time bottom pH and aragonite saturation state (2007-2023) ranged from 7.59-8.15 and 0.64-2.49, respectively. Spatially, the lowest bottom pH and aragonite saturation state have occurred primarily in the western Gulf of Maine, western Long Island Sound, nearshore to mid-shelf waters of the Mid-Atlantic Bight off the coast of New Jersey and New York, and in waters > 1000 meters.
Figure 4. Bottom summer-time (June-August) pH (left panel) and aragonite saturation state (right panel) on the U.S. Northeast Shelf from 2007-2023 plotted from available quality-controlled vessel- and glider-based datasets.
Locations where species sensitivity levels for aragonite saturation state were reached
Using the bottom water aragonite saturation state data, maps depicting locations where summer-time bottom aragonite saturation state reached lab-derived sensitivity levels of designated target species were developed. The target species selected for the Mid-Atlantic were Atlantic sea scallop (Placopecten magellanicus) and longfin squid (Doryteuthis pealeii), and the target species selected for the Gulf of Maine were Atlantic cod (Gadus morhua) and American lobster (Homarus americanus).
Because there were no additional 2023 bottom water aragonite saturation state data available in the Gulf of Maine to update this same product from the previous year’s report, maps for Atlantic cod and American lobster are not included in this year’s catalog page. However, the maps for the individual years between 2007-2022 and the combined map for this same time period are available for these species here. Bottom water data collected during 2023 were incorporated to update this product for the Mid-Atlantic species, Atlantic sea scallop and longfin squid (available here and summarized below). Aragonite saturation state was at or below the sensitivity levels for both Atlantic sea scallop (Placopecten magellanicus) and longfin squid (Doryteuthis pealeii) within their habitat depth ranges in Long Island Sound and the nearshore and mid-shelf regions of the New Jersey/New York shelf. The sensitivity levels of bottom aragonite saturation state occurred during August 2016, July 2018, August 2019, and July-August 2023 for both species, and additionally in August 2021 and August 2022 for the Atlantic sea scallop. The comparison between the 2007-2022 and 2007-2023 maps reveals that the lower aragonite saturation state conditions that occurred in the Mid-Atlantic coastal shelf during summer 2023 increased the spatial range of potentially unfavorable habitat for Atlantic sea scallops and longfin squid compared to the observed past years.
Figure 5. Locations where bottom aragonite saturation state (ΩArag; summer only: June-August) in the habitat depth range were at or below the laboratory-derived sensitivity level for Atlantic sea scallop (top panels) and longfin squid (bottom panels) for the time periods 2007-2022 (left panels) and 2007-2023 (right panels). The sensitivity value used for Atlantic sea scallop was ΩArag ≤ 1.1, based on reduced adult calcification rate observed at this level in @cameron_effects_2022. The sensitivity value used for longfin squid was ΩArag ≤ 0.96, based on embryo and paralarvae malformation, increased time to hatching and decreased hatching success, and changes to mantle length and statolith morphology observed at this level in @zakroff_dose-dependence_2019 and @zakroff_antagonistic_2020. Gray circles indicate locations where carbonate chemistry samples were collected, but bottom ΩArag values were higher than sensitivity values determined for that species and/or samples were collected outside of the species depth range.
Implications
While the sparsity of carbonate chemistry data at annual and seasonal scales to date limits our ability to determine exposure frequency and duration of unfavorable conditions to marine species, locations where recurring low levels of summer-time bottom water pH and aragonite saturation state can be identified from the available data. These areas include the western Gulf of Maine, western Long Island Sound, and nearshore to mid-shelf waters of the Mid-Atlantic Bight off the coast of New Jersey and New York. This information helps to identify potential vulnerable species habitats and can guide future targeted observations aimed at determining stressor exposure frequency and duration and the co-occurrence of additional environmental stressors.
The seasonal level resolution of data collected in the Mid-Atlantic Bight in 2023 revealed the development of low bottom water dissolved oxygen, pH, and aragonite saturation state that co-occurred for over a month during summer through early fall. Mortalities of multiple crustacean and finfish species were reported during this multi-stressor event. The addition of the 2023 data to the bottom water products (2007-2023) highlighted that 2023 may have been an anomalous year that increased the spatial range of potentially unfavorable habitat for local species compared to past observed years. Events such as these that may prevent the ability to sustain normal populations of marine organisms are concerning, not only for the ocean ecosystem but also for the local economy and commercial and recreational fishing industries. Understanding the factors that cause these events will aid in projecting the severity and duration of these events under ongoing climate change and provide important support for guiding policy and management options and identifying priorities for science and monitoring.
Spatial Scale
Seasonal progressions in the Mid-Atlantic (2023), Summer 2023 multi-stressor event in the Mid-Atlantic: New Jersey coastal shelf; Summertime bottom pH and aragonite saturation state on the U.S. Northeast Shelf: full U.S. Northeast Shelf; Locations where species sensitivity levels for aragonite saturation state were reached: Mid-Atlantic Bight
Temporal Scale
Seasonal progressions in the Mid-Atlantic (2023): Spring-Fall 2023; Summer 2023 multi-stressor event in the Mid-Atlantic: Summer (June-August) 2023; Summer-time bottom pH and aragonite saturation state on the U.S. Northeast Shelf: summer (June-August), 2007-2023; Locations where species sensitivity levels for aragonite saturation state were reached: summer (June-August), 2007-2023
Synthesis Theme
Define Variables
1) depth_interpolated meters 2) temperature degrees Celsius 3) chlorophyll_a µg L-1 4) oxygen_concentration_shifted_mgL mg L-1 5) pH_shifted 6) aragonite_saturation_state
Indicator Category
If other, please specify indicator category
No response
Data Contributors
Grace Saba, Lori Garzio
Point(s) of Contact
Grace Saba (saba@marine.rutgers.edu); Lori Garzio (lgarzio@marine.rutgers.edu)
Affiliation
Rutgers University
Public Availability
Source data are publicly available.
Accessibility and Constraints
No response