River of Grass: Hurricanes, Mangroves, and Everglade Resilience

Reflections by Poulomi Chakravarty

Yesterday, I watched RIVER OF GRASS a docu-film directed and produced by Sasha Wortzel and was utterly mesmerized by how it intertwines the living water, the land, and the mangrove tapestry, all beneath the looming shadows of hurricanes. In scenes where sawgrass marshes ebb into mangrove forests, I experienced how water sculpts the land while those salt-tolerant mangroves emerge as guardians, their tangled roots anchoring soils, buffering storms, and absorbing salt surges. These forests are not just a passive scenery; they are the Everglades’ first line of defense against coastal erosion and flooding, the largest continuous mangrove system in the world (Wikipedia, 2025). When hurricanes roar through toppling branches, reshaping coastlines, redistributing seeds and marl they reveal both nature’s fury and its capacity to regenerate. For example, Hurricane Donna in 1960 buried mangroves in marl, severely damaging epiphytes and altering forest composition for decades (Wikipedia, 2025). Nature grieves, but it also endures.

The film, grounded in Marjory Stoneman Douglas’s seminal The Everglades: River of Grass, brings history, ecology, and Indigenous resistance into a single, surging narrative. In the wake of a hurricane, Douglas visits filmmaker Sasha Wortzel in a dream, catalyzing a prismatic study of the Everglades as both wilderness and site of resistance in the face of climate collapse (Wortzel, 2024). On August 14 at Amherst Cinema, I had the privilege of not only watching the film on the big screen but also listening to Wortzel in a post-screening Q&A. Hearing the director speak about weaving Douglas’s archival voice with present-day vérité deepened my appreciation for the project’s layered storytelling and its commitment to centering Indigenous voices.

Image Credit: Photograph by Poulomi Chakravarty during film screening at Amherst Cinema

Hurricanes: Shaping the Everglades' Landscape

Hurricanes are powerful architects of change in the Everglades, fundamentally reshaping its landscape and ecosystems. Historical data show that between 1871 and 2003, tropical cyclones struck the region approximately every one to three years, dramatically altering coastlines, flushing decaying vegetation from estuaries, and dispersing seeds and pollen (Wikipedia, 2025). Notably, Hurricane Donna in 1960 deposited marl over mangrove roots, depriving epiphytes of oxygen and dramatically altering forest composition, a transformation that may take a century to fully recover (Wikipedia, 2025). More recently, Hurricane Irma caused extensive damage to mangrove canopies in coastal zones, with airborne surveys estimating that up to 60% of studied mangrove areas sustained severe damage (NASA Earth Observatory, 2018). Furthermore, storm surges and prolonged ponding following Irma triggered one of the largest recorded diebacks of mangroves, signifying both devastation and ecological vulnerability (Lagomasino et al., 2021).

Image Credit: Landsat 7 image of Hurricane Ian Aftermath on the southwest coast of Florida On October 2, 2022 by USGS on Unsplash

Beneath the Surface: Limestone’s Role in Salinity Balance

Curious about what underpins this wetlands’ resilience geologically, I dove into research on the role of limestone. The Everglades rests upon a porous limestone bedrock, karst terrain formed over eons from calcium carbonate deposition. This foundation filters and balances water chemistry, imparting slight alkalinity that supports specific ecosystems (Wikipedia, 2025). More importantly, the limestone helps to buffer saltwater intrusion through its aquifer storage and natural filtering capacity (Bob Graham Center, 2020).

Sea-level rise and human-altered hydrology, however, are overwhelming this system. Saltwater is not only creeping inland via surface waters but is also percolating through the limestone aquifers, reducing freshwater storage and altering hydrologic function (Bob Graham Center, 2020; AP News, 2024). This intrusion is a key driver of peat collapse and habitat loss, as elevated salinity reduces root biomass and soil elevation, especially in freshwater marshes (Kominoski et al., 2019). Mangroves and freshwater tree islands once buffered are being encroached upon by salt, compromising their ability to maintain freshwater conditions over time (Ross, 2014).

Image Credit: Sasha Wortzel during Q and A session after the film screening, photographed by Sai Gattupalli

Threats, Restoration, Resilience

Saltwater Intrusion & Peat Collapse

Research from Florida International University highlights that increased salinity harms sawgrass root systems and peat integrity, reducing soil elevation and firmness, paving the way for erosion and carbon loss (Kominoski et al., 2019). The intrusion of saltwater is decimating freshwater marshes, and once-stable peat soils are collapsing (Florida International University, 2025).

Mangroves: Buffers & Threatened Sentinels

While mangroves serve as natural buffers, softening the blow of storms and capturing sediment, they face encroachment from the sea. Sea level rise and reduced freshwater flow are pushing them inward, reshaping the ecological boundary between freshwater marsh and coastal forest (Everglades Foundation, 2024; Wikipedia, 2025).

Hurricanes: Catalysts of Change

Hurricanes, beyond their immediate destruction, deposit minerals and marl that can both harm and transform ecosystems. For example, storms can strip away plant life, deposit new soils, and even bring minerals into mangrove forests that boost phosphorus availability but ultimately, the resilience of the system is tested with each event (Castañeda-Moya et al., 2020; Wikipedia, 2025).

Restoration Efforts

The Everglades Restoration Project—the most complex ecological engineering effort in U.S. history, is underway to rehydrate wetlands, restore sheet flow, and mitigate saltwater intrusion (AP News, 2024). More than a dozen state–federal initiatives aim to improve water delivery, elevate bridges like Tamiami Trail, and complete large-scale storage and treatment systems like the EAA Reservoir (AP News, 2024).

Final Reflection

Experiencing River of Grass through everything I’ve learned, I feel more deeply the pulse of an ecosystem bound by water, limestones, roots, and stories. Mangroves sway with memory, hurricanes remind us of nature’s force, and limestone whispers the hidden continuity beneath our feet. Yet, that quiet balance is fraying amidst saltwater intrusion, climate change, and enforced hydrological changes.

If you have a chance, definitely read Marjory Stoneman Douglas’s book and watch the film. They are not just educational but also invitations to listen more deeply to the rivers, both seen and unseen, that sustain us.

Link to the Documentary clip : https://youtu.be/vHugoRBMfBs?si=EZDEhwlmVgIDICyY

Glossary

Dieback – The death or decline of plants starting from leaves or stems and progressing inward, often caused by stressors such as saltwater intrusion, prolonged flooding, nutrient depletion, or storm damage.

Ponding – The accumulation of water on the land’s surface when it cannot drain or infiltrate quickly, often after heavy rain, storm surges, or in flat, saturated landscapes.

Saltwater Intrusion – The movement of seawater into freshwater aquifers or wetlands, usually due to sea-level rise, reduced freshwater flow, or human alterations to water systems.

Peat Collapse – The loss of soil structure in peat-rich wetlands, often following plant root death and decomposition caused by high salinity or extended flooding.

Karst – A type of landscape formed by the dissolution of limestone, featuring porous rock, sinkholes, and underground drainage systems; in the Everglades, it influences water storage and chemistry.

Mangrove – Salt-tolerant trees and shrubs that grow along tropical and subtropical coastlines, providing critical habitat, stabilizing shorelines, and buffering storm surges.

Storm Surge – A rise in sea level caused by strong winds and low atmospheric pressure during hurricanes, capable of flooding coastal and inland areas.

Marl – A calcium carbonate-rich mud or soil that can be deposited by storms, influencing water chemistry and plant growth in wetlands.

Sheet Flow – The slow, shallow movement of water across a wide area, essential to the Everglades’ natural hydrology and the distribution of nutrients.

References

AP News. (2024, December 19). In Florida, a race is on to save the Everglades and protect a key source of drinking water. https://apnews.com/article/f59f0a48e58d2fd3d23169c8b8e54e50

Bob Graham Center. (2020). Mitigating saltwater intrusion through Everglades restoration [Policy proposal]. University of Florida. https://www.bobgrahamcenter.ufl.edu/

Castañeda-Moya, E., Twilley, R. R., Rivera-Monroy, V. H., et al. (2020). Hurricane-induced mineral inputs to near-coast mangroves in the Everglades enhance phosphorus concentrations in soils and plant uptake. PLOS ONE, 15(2), e0229610. https://doi.org/10.1371/journal.pone.0229610

Everglades Foundation. (2024, October 21). Sea level rise and climate change: The Everglades. https://www.evergladesfoundation.org/

Florida International University. (2025). The Everglades: Impacts of saltwater intrusion and peat collapse [Summary]. Florida International University. https://news.fiu.edu/2025/25-years-of-everglades-restoration-has-improved-drinking-water-for-millions-in-florida-but-a-new-risk-is-rising

Kominoski, J. S., Saunders, C. J., Beard, J. S., Troxler, T. G., Gaiser, E. E., & Childers, D. L. (2019). Experimental saltwater intrusion drives rapid soil elevation and carbon loss in freshwater and brackish Everglades marshes. Wetlands, 39(6), 1145–1155. https://doi.org/10.1007/s13157-019-01163-2

Lagomasino, D., et al. (2021). Storm surge and ponding explain mangrove dieback in Florida. Proceedings of the National Academy of Sciences, 118(13), e2024298118. https://doi.org/10.1073/pnas.2024298118

NASA Earth Observatory. (2018, April 19). NASA mapping hurricane damage to Everglades. https://earthobservatory.nasa.gov/images/92033/nasa-mapping-hurricane-damage-to-everglades

Ross, M. S. (2014). Compositional effects of sea-level rise in a patchy landscape. PeerJ, 2, e684. https://doi.org/10.7717/peerj.684

Wikipedia. (2025). Geography and ecology of the Everglades. In Wikipedia. https://en.wikipedia.org/wiki/Geography_and_ecology_of_the_Everglades

Wortzel, S. (Director). (2024). River of Grass. https://www.riverofgrassfilm.com/

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