About

Professor Justin Ries is a faculty member in the Department of Marine and Environmental Sciences at Northeastern University College of Science. His research program investigates a wide range of subjects in the marine and geological sciences, including global climate change, paleoceanography, paleobiology, carbonate sedimentology, sulfur isotope geochemistry, biomineralization, and carbon sequestration. The common thread throughout Professor Ries’ work is oceanic change, which he investigates over broad temporal scales. By combining field studies with complementary laboratory experiments, he explores the biogeochemical processes that have changed the state of our oceans throughout the geologic past, as well as those that will drive critical changes in the immediate future.

Research topics

• Environmental science
• Biology
• Ecology
• Geography
• Oceanography
• Materials science
• Geology
• Chemistry

Selected publications

• Differing proteome responses to ocean acidification between two common pocilloporid corals

  Coral Reefs · 2025-12-08

  articleOpen access

  Abstract Ocean acidification threatens coral reef ecosystems by challenging calcification processes fundamental to reef accretion. Yet many corals continue to calcify under elevated p CO 2 , suggesting species-specific physiological plasticity and potential cellular compensations. Here, we use label-free quantitative proteomics to investigate proteomic responses of two common pocilloporid corals, Stylophora pistillata and Pocillopora damicornis , with known differential resistance to ocean acidification after two months at moderate (~ 940 ppm) and high (~ 2,800 ppm) p CO 2 compared to the control (~ 480 ppm). S. pistillata exhibited extensive proteomic restructuring under high p CO 2 , marked by widespread declines of energy-generating pathways, yet selective increase of proteins involved in ion transport, cytoskeletal stability, and stress responses. This indicates a strategy of general metabolic suppression coupled with targeted investment into essential cellular functions, potentially sustaining calcification despite reduced overall metabolic capacity. In contrast, P. damicornis showed much less proteomic adjustment, primarily involving structural proteins and those potentially linked to cellular redox balance, signifying a moderate, targeted strategy for physiological stability. These divergent responses highlight contrasting modes of resistance (plasticity versus stability). Integrated with physiological data, our findings clarify cellular mechanisms controlling calcification, demonstrating the value of proteomics in coral ecophysiology and providing new insights into species-specific vulnerability under future ocean conditions.

  PublisherOA PDFDOI

• Magnesium (Mg∕Ca, <i>δ</i> ²⁶ Mg), boron (B∕Ca, <i>δ</i> ¹¹ B), and calcium (Ca ²⁺ ) geochemistry of <i>Arctica islandica</i> and <i>Crassostrea virginica</i> extrapallial fluid and shell under ocean acidification

  Biogeosciences · 2025-06-19 · 4 citations

  articleOpen access

  Abstract. The geochemistry of biogenic carbonates has long been used as proxies to record changing seawater parameters. However, the effect of ocean acidification (OA) on seawater chemistry and organism physiology could impact isotopic signatures and how elements are incorporated into the shell. In this study, we investigated the geochemistry of three reservoirs important for biomineralization – seawater, the extrapallial fluid (EPF), and the shell – in two bivalve species: Crassostrea virginica and Arctica islandica. Additionally, we examined the effects of three ocean acidification conditions (ambient: 500 ppm CO2, moderate: 900 ppm CO2, and high: 2800 ppm CO2) on the geochemistry of the same three reservoirs for C. virginica. We present data on calcification rates, EPF pH, measured elemental ratios (Mg/Ca, B/Ca), and isotopic signatures (δ26Mg, δ11B). In both species, comparisons of seawater and EPF Mg/Ca and B/Ca, Ca2+, and δ26Mg indicate that the EPF has a distinct composition that differs from seawater. Shell δ11B did not faithfully record seawater pH, and δ11B-calculated pH values were consistently higher than pH measurements of the EPF with microelectrodes, indicating that the shell δ11B may reflect a localized environment within the entire EPF reservoir. In C. virginica, EPF Mg/Ca and B/Ca, as well as absolute concentrations of Mg2+, B, and Ca2+, were all significantly affected by ocean acidification, indicating that OA affects the physiological pathways regulating or storing these ions, an observation that complicates their use as proxies. Reduction in EPF Ca2+ may represent an additional mechanism underlying reduction in calcification in C. virginica in response to seawater acidification. The complexity of dynamics of EPF chemistry suggests boron proxies in these two mollusk species are not straightforwardly related to seawater pH, but ocean acidification does lead to both a decrease in microelectrode pH and boron-isotope-based pH, potentially showing applicability of boron isotopes in recording physiological changes. Collectively, our findings show that bivalves have high physiological control over the internal calcifying fluid, which presents a challenge in using boron isotopes for reconstructing seawater pH.

  PublisherOA PDFDOI

• Gene expression plasticity facilitates acclimatization of a long-lived Caribbean coral across divergent reef environments

  Scientific Reports · 2024-04-03 · 13 citations

  articleOpen access

  Local adaptation can increase fitness under stable environmental conditions. However, in rapidly changing environments, compensatory mechanisms enabled through plasticity may better promote fitness. Climate change is causing devastating impacts on coral reefs globally and understanding the potential for adaptive and plastic responses is critical for reef management. We conducted a four-year, three-way reciprocal transplant of the Caribbean coral Siderastrea siderea across forereef, backreef, and nearshore populations in Belize to investigate the potential for environmental specialization versus plasticity in this species. Corals maintained high survival within forereef and backreef environments, but transplantation to nearshore environments resulted in high mortality, suggesting that nearshore environments present strong environmental selection. Only forereef-sourced corals demonstrated evidence of environmental specialization, exhibiting the highest growth in the forereef. Gene expression profiling 3.5 years post-transplantation revealed that transplanted coral hosts exhibited profiles more similar to other corals in the same reef environment, regardless of their source location, suggesting that transcriptome plasticity facilitates acclimatization to environmental change in S. siderea. In contrast, algal symbiont (Cladocopium goreaui) gene expression showcased functional variation between source locations that was maintained post-transplantation. Our findings suggest limited acclimatory capacity of some S. siderea populations under strong environmental selection and highlight the potential limits of coral physiological plasticity in reef restoration.

  PublisherOA PDFDOI

• Gene expression plasticity facilitates acclimatization of a long-lived Caribbean coral across divergent reef environments

  UNC Libraries · 2024-11-01 · 1 citations

  articleOpen access
  PublisherDOI

• Magnesium (Mg/Ca, δ ²⁶ Mg), boron (B/Ca, δ ¹¹ B), and calcium ([Ca ²⁺ ]) geochemistry of Arctica islandica and Crassostrea virginica extrapallial fluid and shell under ocean acidification

  2024-08-12

  preprintOpen accessCorresponding

  Abstract. The geochemistry of biogenic carbonates has long been used as proxies to record changing seawater parameters. However, the effect of ocean acidification on seawater chemistry and organism physiology could impact isotopic signatures and how elements are incorporated into the shell. In this study, we investigated the geochemistry of three reservoirs important for biomineralization – seawater, the extrapallial fluid (EPF), and the shell – in two bivalve species, Crassostrea virginica and Arctica islandica. Additionally, we examined the effects of three ocean acidification conditions (ambient: 500 ppm CO2, moderate: 900 ppm CO2, and high: 2800 ppm CO2) on the geochemistry of the same three reservoirs for C. virginica. We present data on calcification rates, EPF pH, measured elemental ratios (Mg/Ca, B/Ca), and isotopic signatures (δ26Mg, δ11B). In both species, comparisons of seawater and EPF Mg/Ca and B/Ca, [Ca2+], and δ26Mg indicate that the EPF has a distinct composition that differs from seawater. Shell δ11B did not faithfully record seawater pH and δ11B-calculated pH values were consistently higher than pH measurements of the EPF with microelectrodes, indicating that the shell δ11B may reflect a localized environment within the entire EPF reservoir. In C. virginica, EPF Mg/Ca and B/Ca, as well as absolute concentrations of Mg, B, and [Ca2+], were all significantly affected by ocean acidification, indicating that OA affects the physiological pathways regulating or storing these ions, an observation that complicates their use as proxies. Reduction in EPF [Ca2+] may represent an additional mechanism underlying reduction in calcification in C. virginica in response to seawater acidification. The complexity of dynamics of EPF chemistry suggest boron proxies in these two mollusc species are not straightforwardly related to seawater pH, but ocean acidification does lead to both a decrease in microelectrode pH and boron-isotope-based pH, potentially showing applicability of boron isotopes in recording physiological changes. Collectively, our findings show that bivalves have high physiological control over the internal calcifying fluid, which presents a challenge to using boron isotopes for reconstructing seawater pH.

  PublisherOA PDFDOI

• Century‐Long Records of Sedimentary Input on a Caribbean Reef From Coral Ba/Ca Ratios

  Paleoceanography and Paleoclimatology · 2024-05-01 · 5 citations

  articleOpen access

  Abstract Coral reef ecosystems are delicately balanced and are thus prone to disruption by stressors such as storms, disease, climate variability and natural disasters. Most tropical coral populations worldwide are now in rapid decline owing to additional anthropogenic pressures, such as global warming, ocean acidification and a variety of local stressors. One such problem is the addition of excess sediment and nutrients flux to reefs from increased soil erosion from land use changes. Here we present century‐long Ba/Ca records from two Siderastrea siderea colonies as a proxy for local riverine discharge and sediment flux to the southern Mesoamerican Barrier Reef System (MBRS). The coral colonies have linear extension trends, which can be seen as a first‐order indicator for coral health and response. The coral colony that exhibits a decline in linear extension rate from the forereef of the MBRS, mainly receives riverine input from Honduras, whilst the coral from the backreef, which does not exhibit a decline in extension rate, primarily receives riverine input from more sparsely populated regions of Belize. Coral Ba/Ca increased (&gt;70%) through time in the forereef colony, while the backreef colony showed little long‐term increase in Ba/Ca over the last century. Our results suggest that increasing sediment supply may have played a role in the decline of forereef skeletal extension in the southernmost MBRS region, likely stemming from increasing land‐use changes in Honduras.

  PublisherOA PDFDOI

• Comment on sp-2023-2

  2023-08-16

  peer-reviewOpen access1st authorCorresponding

  <strong class="journal-contentHeaderColor">Abstract.</strong> Monitoring, Reporting, and Verification (MRV) refers to the multistep process of monitoring the amount of greenhouse gas removed by a Carbon Dioxide Removal (CDR) activity and reporting the results of the monitoring to a third party. The third party then verifies the reporting so the results. While MRV is usually conducted in pursuit of certification in a voluntary or regulated CDR market, this chapter focuses on key recommendations for MRV relevant to ocean alkalinity enhancement (OAE) research. Early-stage MRV for OAE research may become the foundation on which markets are built. Therefore, we argue that such research carries a special obligation toward comprehensiveness, reproducibility, and transparency. Observational approaches during field trials should aim to quantify the delivery of alkalinity to seawater and monitor for secondary precipitation, biotic calcification, and other ecosystem changes that can feed back on sources or sinks of greenhouse gases where alkalinity is measurably elevated. Observations of resultant shifts in ocean pCO₂ and pH can help determine the efficacy of OAE and are amenable to autonomous monitoring. However, because the ocean is turbulent and energetic and CO₂ equilibration between the ocean and atmosphere can take several months or longer, added alkalinity will be diluted to perturbation levels undetectable above background variability on timescales relevant for MRV. Therefore, comprehensive quantification of carbon removal via OAE will be impossible through observational methods alone and numerical simulations will be required. The development of fit-for-purpose models, carefully validated against observational data, will be a critical part of MRV research.

  PublisherDOI

• Comment on sp-2023-1

  2023-09-13

  peer-reviewOpen access1st authorCorresponding

  <strong class="journal-contentHeaderColor">Abstract.</strong> Ocean alkalinity enhancement (OAE) is an emerging strategy that aims to mitigate climate change by increasing the alkalinity of seawater. This approach involves increasing the alkalinity of the ocean to enhance its capacity to absorb and store carbon dioxide (CO₂) from the atmosphere. This chapter presents an overview of the technical aspects associated with the full range of OAE methods being pursued and discusses implications for undertaking research on these approaches. Various methods have been developed to implement OAE, including: the direct injection of alkaline liquid into the surface ocean, dispersal of alkaline particles from ships, platforms or pipes, the addition of minerals to coastal environments, or the electrochemical removal of acid from seawater. Each method has its advantages and challenges, such as scalability, cost-effectiveness, and potential environmental impacts. The choice of technique may depend on factors such as regional oceanographic conditions, alkalinity source availability, and engineering feasibility. This chapter considers electrochemical methods, the accelerated weathering of limestone, ocean liming, the creation of hydrated carbonates, and the addition of minerals to coastal environments. In each case, the technical aspects of the technologies are considered and implications for best-practice research are drawn. The environmental and social impacts of OAE will likely depend on the specific technology and the local context in which it is deployed. Therefore, it is essential that the technical feasibility of OAE is undertaken in parallel with, and informed by, wider impact assessments. While OAE shows promise as a potential climate change mitigation strategy, it is essential to acknowledge its limitations and uncertainties. Further research and development are needed to understand the long-term effects, optimize techniques, and address potential unintended consequences. OAE should be viewed as complementary to extensive emission reductions, and its feasibility may be improved if it is operated using energy and supply chains with minimal CO₂ emissions.

  PublisherDOI

• Linear extension and calcification rates in a cold‐water, crustose coralline alga are modulated by temperature, light, and salinity

  Limnology and Oceanography · 2023-12-10 · 2 citations

  articleOpen accessSenior author

  Abstract Long‐lived crustose coralline algae are important ecosystem engineers and environmental archives in regions where observations of climate variability are sparse. Clathromorphum compactum is a cold‐water alga that precipitates calcite that serve as archives of change at annual to sub‐annual resolution. Understanding how environmental variability impacts the growth of this species is imperative for application in paleoclimate research, and for evaluating its vulnerability to change. Here, we present the results of the first, to‐our‐knowledge, controlled laboratory experiment isolating the effects of light, temperature, and salinity on calcification rates of C. compactum . Algal calcification rates were modulated by a combination of light exposure, salinity, and temperature, where temperature and salinity were positively correlated, and light level was negatively correlated with calcification rate. Linear extension of the skeleton also varied with treatment conditions, with the epithallial and perithallial layers of skeleton responding differently. Epithallial extension increased with salinity, while perithallial extension was governed only by a positive parabolic relationship with temperature. These results suggest that C. compactum growth will be impacted by environmental changes predicted for the Arctic over the coming decades. While increased temperature in the region may facilitate calcification in the algae, reductions in salinity associated with increased sea ice melt, and potentially increased light levels, may counteract this effect. The negative impact of increased light levels on algal calcification observed may not reflect the true impact of light availability on growth associated with a lengthening of the growing season (not evaluated in this study) accompanying reductions in annual sea‐ice.

  PublisherOA PDFDOI

• Dual carbonate clumped (Δ₄₇, Δ₄₈) and bulk (δ¹³C, δ¹⁸O) isotopes in cultured marine calcifiers provide insights into the origins of vital effects

  2023-01-01

  articleOpen access
  PublisherOA PDFDOI

Recent grants

• Investigation of the Effects of CACO3 Saturation State & Temperature on the Calcification Rate & Skeletal Properties of Benthic Marine Calcifiers

  NSF · $375k · 2013–2015

• Collaborative Research: Development and application of a method using coralline algae to reconstruct past changes in pH and impacts on calcification

  NSF · $331k · 2015–2021

• MRI: Acquisition of a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) for research in the marine, earth and environmental sciences

  NSF · $500k · 2014–2020

• Collaborative Research: A combined boron isotope, pH microelectrode and pH-sensitive dye approach to constraining acid/base chemistry in the calcifying fluids of corals

  NSF · $369k · 2014–2020

• Investigation of the Effects of CACO3 Saturation State & Temperature on the Calcification Rate & Skeletal Properties of Benthic Marine Calcifiers

  NSF · $656k · 2010–2013

Frequent coauthors

• Robert A. Eagle

  University of California, Los Angeles

  83 shared

• Isaac Westfield

  Northeastern University

  43 shared

• Louise P. Cameron

  Northeastern University

  36 shared

• Maxence Guillermic

  University of California, Los Angeles

  34 shared

• Karl D. Castillo

  University of North Carolina at Chapel Hill

  30 shared

• Hildegard Westphal

  Leibniz Centre for Tropical Marine Research

  27 shared

• Jill Sutton

  Université de Bretagne Occidentale

  22 shared

• Gavin L. Foster

  University of Southampton

  18 shared