About

Sergio Fagherazzi is a professor in the Department of Earth & Environment at Boston University. He studies geomorphology, hydrology, and coastal and marine geology. His research is oriented in three main directions: the morphological modeling of the continental shelf, including the formation and evolution of riverine networks during sea-level lowstands and subsequent channel filling during high-stands; the study of the hydrodynamics and morphology of salt marshes, focusing on the observation, understanding, and modeling of creeks and channels developing on a salt marsh surface; and the numerical study of equations characteristic of coastal processes and hydrology, developing dynamic models that link phenomena occurring at different spatial scales. Fagherazzi holds a Ph.D. from the University of Padua, Italy, obtained in 1999, and a B.S. from the same university. He teaches courses such as Crises of the Planet, Quantitative Morphology, and Estuaries & Nearshore Systems.

Research topics

• Environmental science
• Geology
• Oceanography
• Geomorphology
• Ecology
• Remote sensing
• Geography
• Computer Science
• Computer vision
• Physical geography
• Cartography

Selected publications

• Mechanisms of wetland deterioration in a sinking deltaic lagoon

  2026-03-13

  articleOpen access1st authorCorresponding

  Coastal wetlands are vegetated landforms that offer a multitude of ecosystem services to society. The vulnerability of these ecosystems to relative sea-level rise (RSLR) is connected to the amount of suspended sediment available in the adjacent water bodies. Sediment is transported by numerous processes onto the wetland surface, where it can contribute to vertical accretion and counteract RSLR. Here, we used maps of total suspended solids (TSS) concentration from the NASA Airborne Visible InfraRed Imaging Spectrometer Next Generation (AVIRIS-NG), numerical modeling, aerial imagery, and field observations to infer the mechanisms controlling wetland dynamics within western Terrebonne Bay, a sinking lagoon in the Mississippi River Deltaic Plain. Specifically, we aimed to understand how wetlands respond when land sinks, using western Terrebonne Bay as a test case. This study revealed that subsidence can augment suspended sediment in the water column by increasing tidal prism and triggering channel erosion. Sediment resuspension can support accretion in the remaining wetland platforms, ultimately affecting their elevation. Understanding these feedback mechanisms has direct implications for forecasting and managing the impacts of RSLR on wetlands in lagoons and river deltas.

  PublisherDOI

• Estimating net sediment fluxes in tidal systems using sporadic datasets: Implications for using remote sensing to assess saltmarsh resilience

  2026-03-02

  articleOpen access

  Sediment budgets are diagnostic of saltmarsh resilience, yet quantifying net sediment fluxes remains constrained by limited, asynchronous observations of suspended sediment concentration (SSC) and water flux. Using high-frequency observations from 15 U.S. saltmarsh stations, we combine phase folding and Monte-Carlo simulations to assess whether sporadic sampling can reliably resolve net sediment exchange. We show that asynchronous SSC and water-flux measurements spanning >8 full tidal cycles robustly identify sediment sources and sinks. High-resolution optical satellite archives (Sentinel-2) typically capture >30 tidal cycles in most saltmarshes, yielding 5–41% uncertainty in net flux magnitude across systems. This accuracy is sufficient to distinguish saltmarshes functioning as sediment sources from those acting as sinks at regional to global scales, though local calibration could improve accuracy. Integrating optical remote sensing with emerging water-flux technologies can therefore enable scalable assessments of tidal saltmarsh sediment budgets, providing a pathway for evaluating coastal resilience under accelerating sea-level rise.

  PublisherOA PDFDOI

• Mechanisms of wetland deterioration in a sinking deltaic lagoon

  Estuarine Coastal and Shelf Science · 2026-02-03

  articleSenior author
  PublisherDOI

• Suspended Sediment Dynamics in a Mesotidal Estuarine Channel Revealed by Numerical Modeling and Remote Sensing of Sediment Concentrations

  2026-03-13

  articleOpen accessSenior authorCorresponding

  Process-based sediment transport models can accurately reproduce estuarine sediment dynamics when boundary fluxes, bed properties, and spatially resolved sediment characteristics are well constrained; however, such information is rarely available in most coastal systems. Sediment fluxes at the ocean boundary are commonly unconstrained, riverine sediment inputs are typically estimated from stage–discharge relationships combined with reference concentrations rather than measured continuously, and bottom sediment properties are seldom resolved at high spatial resolution. These limitations hinder robust quantification of suspended sediment redistribution in intertidal estuaries. Here, suspended sediment balance is evaluated in Plum Island Sound (Massachusetts, USA), a mesotidal estuary, by integrating surface suspended sediment concentration (SSC) derived from Sentinel-2 MSI imagery (10 m resolution) with numerical simulations of hydrodynamics. We implemented the depth-integrated suspended sediment balance under quasi-steady conditions during satellite overpasses for erosion-deposition distribution. Six hydrodynamic configurations are analyzed, defined by tidal phase (flood or ebb), river discharge magnitude (high or low), and wind forcing (calm or high wind). The results reveal pronounced tidal asymmetry in sediment redistribution, with flood and ebb tides producing spatially distinct erosion and deposition patterns, particularly within channel bends. Elevated river discharge increases SSC in the upper estuary but does not generate substantial downstream redistribution under calm conditions, whereas wind-driven events induce widespread resuspension and enhanced sediment redistribution across the system. This work demonstrates how coupling remote sensing observations with hydrodynamic modeling enables geomorphologically analysis of suspended sediment balance in estuarine environments.

  PublisherDOI

• Pre-storm hydrology buffers saltwater intrusion in coastal forests

  Journal of Hydrology · 2026-03-16

  articleSenior author
  PublisherDOI

• Climate change influences coastal protection value of global wetlands

  Science Bulletin · 2026-03-27 · 1 citations

  article
  PublisherDOI

• The Ecohydrology of Coastal Ghost Forests

  2026-03-13

  articleOpen access1st authorCorresponding

  Sea level rise and storm surges affect coastal forests along low-lying shorelines. Salinization and flooding kill trees and favour the encroachment of salt-tolerant marsh vegetation. The hydrology of this ecological transition is complex and requires a multidisciplinary approach. Sea level rise (press) and storms (pulses) act on different timescales, affecting the forest vegetation in different ways. Salinization can occur either by vertical infiltration during flooding or from the aquifer driven by tides and sea level rise. Here, we detail the ecohydrological processes acting in the critical zone of retreating coastal forests. An increase in sea level has a three-pronged effect on flooding and salinization: It raises the maximum elevation of storm surges, shifts the freshwater-saltwater interface inland, and elevates the water table, leading to surface flooding from below. Trees can modify their root systems and local soil hydrology to better withstand salinization. Hydrological stress from intermittent storm surges inhibits treegrowth, as evidenced by tree ring analysis. Tree rings also reveal a lag between the time when tree growth significantly slows and when the tree ultimately dies. Tree dieback reduces transpiration, retaining more water in the soil and creating conditions more favourable for flooding. Sedimentation from storm waters combined to organic matter decomposition can change the landscape, affecting flooding and runoff. Our results indicate that only a multidisciplinary approach can fully capture the ecohydrology of retreating forests in a period of accelerated sea level rise.

  PublisherDOI

• Deriving bottom sediment grain size in tidal channels using remote sensing and numerical modeling

  Limnology and Oceanography Methods · 2026-02-17

  articleSenior author

  Abstract Bottom sediments in tidal estuaries influence organic matter and nutrient cycling, habitat suitability, and geomorphological processes. Characterizing the grain size distribution of bottom sediments is essential for predicting sediment transport, channel stability, and ecosystem health. However, this information can be challenging to acquire over large areas as traditional in situ approaches provide only point‐based observations that are spatially limited. This study addresses this limitation by applying the sediment balance equation to remotely sensed maps of total suspended solids concentration and numerical model outputs to derive a high‐resolution, spatially explicit sediment grain size distribution within a tidal channel of a New England mesotidal estuary. Results reveal a distinct gradient in sediment grain size, with coarse sediments near the inlet transitioning to finer sediments landward. Fine sand covers over 85% of the channel bottom, while medium and coarse sand occupy 14% and 1%, respectively. Peaks in settling velocity identify zones of sediment convergence controlled by tidal forcing and river inflows. The positive correlation between , estimated through the depth integrated suspended sediment continuity equation, and bottom grain size confirms the effectiveness of this approach for sediment classification in estuarine environments.

  PublisherDOI

• Evidence of enhanced global vegetation activity driven by reduced human pressures

  Ecological Indicators · 2026-03-08

  articleOpen access

  The COVID-19 pandemic provided an unprecedented natural experiment to assess vegetation responses to reduced anthropogenic pressures. We developed a multi-scale framework synthesizing policy stringency, human mobility, and remote sensing data to quantify pandemic impacts on global vegetation. Specifically, we constructed a spatially explicit Human Modification Stringency Index to capture relative shifts in human activity from 2017 to 2023, while characterizing vegetation dynamics using Dynamic World land cover and MODIS NDVI. Our results reveal that global vegetation area, which had declined by ∼2.3 million km 2 before the pandemic, rebounded with a net gain of ∼2.9 million km 2 during the pandemic. This reversal was corroborated by growing-season NDVI, which transitioned from browning (−0.0021) to greening (+0.0056). Using a continuous Difference-in-Differences model across ∼28.3 million pixels, we causally attributed this greening to reduced human disturbance in 96.6% of significant grid cells. The effects peaked in 2022 before diminishing as restrictions eased. Notably, moderately human-modified landscapes showed the most widespread recovery, whereas heavily modified areas exhibited the greatest magnitude of change, suggesting substantial latent vegetation recovery potential. These findings highlight that targeted reductions in anthropogenic pressures can drive rapid vegetation recovery, offering critical insights for ecological restoration and land management. • Global vegetation increased by ∼2.9 million km 2 during the COVID-19 pandemic. • Novel Human Modification Stringency Index quantified pressure reductions. • Continuous DID model decoupled anthropogenic effects from climatic drivers. • Greening was most prevalent in semi-modified but greatest in heavily modified areas.

  PublisherDOI

• Monitoring coastal shoreline change using PlanetScope imagery

  Estuarine Coastal and Shelf Science · 2026-02-18

  articleOpen access

  Accurate monitoring of shoreline change is essential for assessing coastal vulnerability, yet traditional field surveys and airborne mapping are costly, logistically demanding, and spatially limited. Here, we present an automated workflow that leverages high-spatial-resolution (≈3 m), near-daily PlanetScope imagery to detect multi-year shoreline change across diverse coastlines. Rather than extracting instantaneous shoreline positions, the method exploits dense, multi-year time series of the Normalized Difference Water Index (NDWI) to quantify pixel-based temporal trends, which are extrapolated to consistent start ( T 0 ) and end dates ( T f ). This approach yields extrapolated shoreline positions at T 0 and T f that represent long-term erosion and deposition patterns while suppressing the influence of short-term and seasonal water-level variability, episodic events, and optical noise. The workflow was developed and tested across twelve U.S. National Park Service coastal sites, eight of which include field-surveyed reference shorelines. Remotely sensed shoreline-change maps for the 2017-2021 time period showed strong spatial agreement with survey-derived erosion and deposition patterns, and estimated change areas were within ±20% of field benchmarks despite inherent temporal differences between instantaneous surveys and extrapolated shoreline positions. Application at four additional sites lacking field surveys demonstrated broad geographic robustness while revealing limitations in settings characterized by subtle lateral changes or periodically inundated vegetation. The workflow is computationally efficient, scalable, and well-suited for reconnaissance-level assessments to inform coastal management and prioritize field efforts. Although it is not designed to resolve short-term shoreline morphodynamics, it provides a practical framework to identify multi-year erosion and deposition patterns from 2017 onward across diverse coastlines. • Rapid shoreline-change detection using PlanetScope imagery • Remotely sensed multi-year shoreline change is consistent with field surveys • Approach enables automated shoreline assessments to identify vulnerable areas • Broad applicability across diverse coastal shorelines

  PublisherDOI

Recent grants

• Collaborative Research: Network Cluster: The Coastal Critical Zone: Processes that transform landscapes and fluxes between land and sea

  NSF · $261k · 2020–2025

• Collaborative Research: Modeling Sediment Delivery and Related Stratigraphy in a Tidal Dominated Delta: Fly River Papua, New Guinea

  NSF · $69k · 2005–2008

• MARGINS Post-Doctoral Fellowship: A synthesis model for the Fly River dispersal system, Papua New Guinea

  NSF · $188k · 2010–2013

• Collaborative Research: Ecosystem Evolution and Sustainability of Nutrient Enriched Coastal Saltmarshes

  NSF · $108k · 2014–2018

• ETBC Collaborative Research: Feedbacks between nutrient enrichment and intertidal sediments: erosion, stabilization, and landscape evolution

  NSF · $897k · 2009–2014

Frequent coauthors

• G. Mariotti

  Louisiana State University

  52 shared

• Olivier Gourgue

  43 shared

• William Nardin

  University of Maryland Center for Environmental Science

  35 shared

• Stijn Temmerman

  34 shared

• Nicoletta Leonardi

  32 shared

• Patricia L. Wiberg

  University of Virginia

  28 shared

• Jean‐Philippe Belliard

  University of Antwerp

  27 shared

• Carmine Donatelli

  The University of Texas at Austin

  25 shared

Labs

• Sergio FagherazziPI

Education

• PhD in Civil Engineering

  University of Padua

  1999