Sonic blind spots: Acoustic research in the Lower Mississippi River

By: Margarida Mendes

The engine repeats, the pump withdraws. We get sucked into discharge channels and trapped in backwaters. Radioactive dust on the horizon. Walls and ponds of waste get mixed in the water, corroding my fingerprints. Nitrogen levels peak, as the core samples glow. When we row, the waterline is subdued to a foam border, envisioned by ants as a nutritious conveyor of wealth. The intermixed canals of this chemical pond become the infrasonic rhythmic sites of industry’s growth. Water shivers, water glows. In the mountainous intertidal range of cultivated dispossessed lands. Plantations gave place to petrochemical labyrinths for incarcerated souls. Swamp people, once marooned free, are now exposed to the ravaging control of uncertainty. The cicadas warm the air with their precious blues, inexhaustible tremors marking the mid-afternoon. As the season of termites sleeps, the crepuscule soon brings the howling dawn, and with it its cricketing hum — in the corners, in the marshes, in the mallows. The songs of a thousand frogs echo from bellow, attuned to the environment of encircling flows. The echo brings the gecko, the Mississippi in a thousand rows.

I joined the Augsburg University River Semester on the last leg of its journey travelling down the Mississippi from Baton Rouge to New Orleans. I pursued a project titled Sounding the Mississippi. I collected recordings of the petrochemical corridor soundscape, as I documented the lower Mississippi River as an acoustic space, using sound as a tool to environmentally sense my way into this ecosystem. I recorded sound with a hydrophone and zoom recorder microphone, both above and below the water line, as I canoed or whenever we had a stop on the riverbanks. In the end of the day, I played back the recordings and had conversations about riverine noise and the transformations of its habitats, as I tried to make sense of the scale of extraction operating at site. By registering the exceedingly industrialised soundscape of its the riverine embankments, and surrounding infrastructure, I studied the continuity between bodies and the environment. While searching for sonic residues of toxicity, I revisited my thoughts about the impermanence of matter and the mutability of the hydrocycle, reframing the river as living geological strata, and its surrounding riverine system as a complex metabolic site, where numerous transactions occur. I also inquired into how much is known about these ecosystems, and how much is left unregistered, untraceable, or out of the frame, and what tools, epistemological questionings or blind spots were left unanswered, and how these shaped or were the result of research practices.


Months after our journey, as I struggled to find any acoustic ecology researcher that had set their ears set on this over-industrialised stretch of the Mississippi reaching the Gulf of Mexico, I still wondered how the disturbing omnipresent background noise was disregarded both by local inhabitants and by the scientific community. I set out to make a series of interviews on the topic, and my first encounter was with Natalia Sidorovskaia, a senior researcher at University of Louisiana at Lafayette and one of the most experienced acousticians in the region, who conducted work in the Gulf monitoring oil drilling impacts in the cetacean community. She was intrigued by my intention to use sound as a tool to environmentally sense this stretch of the river, and how unprecedented cross-readings of water and atmospheric pollution across both human and other-than-human entities could bring different perspectives about an ecosystem under distress.  

I asked her and several other researchers if the infrastructural rhythms of Louisiana could leave a physical imprint on the bodies that inhabit it, whose vital expression seems to be endangered by the surrounding industry. Sidorovskaia told me that there is still much to study. Only few maps of pollution include electromagnetic properties in relation to soil geophysics. In terms of acoustic ecology, no maps exist of the petrochemical corridor. Everybody is focused on the Gulf, where biodiversity is more representative, and not on the river itself. According to Sidorovskaia, local scientific research on cetaceans could do much more to understand what acoustic communication is and how animals utilise it:

We can detect species using acoustical signals, and do some prediction of abundance of population, we know we can use this acoustic database to understand the structure, genders, for example. But, as for recognising individuals and understanding communication, I think these should be two immediate goals for marine mammals’ future research.[1]

Sidorovskaia went on to speak about the impact that ocean noise makes on the species she has studied, acknowledging that the more subtle impacts of high baseline noise were left unregistered in her study. She and her colleagues noticed how cetaceans change their communication overtime as industrial noise grows, competing with industry by producing higher sounds to communicate with one another or to find prey. But the details of this adaptation remained unknown to the scientific team. This led her lab to inquire further into underwater sound signals by focusing for example on their reproductive utility among fish. According Sidorovskaia, acoustics is “everything” in the ocean:

because there are no images in the ocean, they [the animals] cannot see. There’s no light down there, so everything they know about the ocean is mostly smell and acoustics. That’s their vision of the world. What they use is the kind of information they can extract based on the acoustic signals produced.[2]

If acoustics is the main medium for aquatic environmental assessment, then clearly my conversation with Sidorovskaia has pointed several blind spots in scientific research directions. Most of the research conducted concerns ocean animals, and not the riverine and Delta communities, or other animals, and humans on land. There are considerable studies related to military industry and submarine use in coastal waters, with the first data reports from 1990, but no reports on the lower stretch of the river. Teams collect coastal acoustic baseline data and monitor the impact of oil drilling through acoustic surveys and through the study of whale behaviour changes recorded in audiograms. However, their data cannot explain the absence of animals; it can only distinguish between the sizes of animals, particularly calves, through algorithms.

Sidorovskaia mentioned that the databanks are shared with NASA and SCRIPPS Institution of Oceanography. However, the datasets are endless and it is difficult to process all the material collected. And then there is the fact that incorporating these results in any kind of legislation would take decades. These blind spots in scientific research suggest possible reasons behind the erasure of the Delta and petrochemical corridor as an object of study: either lack of funding, or the omnipresence of the petrochemical industry in the area and its control over scientific research on the river. Much remains to be said about the evolutionary adaptation of species to the massive environmental changes that extraction and intensive agriculture brought to the Mississippi, let alone about how infrastructural and engineering investments have been altering the behaviour of species.


Infrastructures of extraction by the riverbanks of the Lower Mississippi

Infrastructures of extraction by the riverbanks of the Lower Mississippi (the author’s photograph).


How do we sense the environment and how does the environment sense us?

Bernie Krauss’ acoustic niche hypothesis speaks of animal adaptation to anthropogenic noise.[3] He predicts, that in a mature ecosystem, species will avoid competition by singing at unique bandwidths or pitches, and at different times. Therefore, no two species should sing simultaneously at the same frequency. The hypothesis moreover suggests that more mature ecosystems will exhibit pronounced partitioning of the sound spectrum while young or disturbed ecosystems will exhibit greater acoustic disorganisation, with multiple species interfering in the same bandwidths. The degree of acoustic partitioning in a given soundscape is directly related to the habitat quality and biodiversity of that ecosystem.

This bioacoustics theory focuses on simultaneous spectrum occupation by different species, who lay territorial claims to several audio thresholds. Acoustic biologist Mark Bee working upriver in the Mississippi studies similar phenomena, investigating what we can learn from the environment and ourselves by studying frog songs.[4] Bee speculates that we might find auditory solutions if we link back to an ancestor common to both modern-day fish and terrestrial vertebrates – amphibians, reptiles, birds, and mammals – who 400 million years ago might have developed a sense of hearing underwater. Bee’s lab analyses frog responses to mating calls in spaces of high background noise density. His study has concluded that female frogs are less likely to find a mating partner and reproduce in noisy environments; noise constrains the spatial scale and extent of a female’s ability to assess and compare different mates in a chorus. Frogs, like humans, explore similar auditory solutions. exploiting spatial separation as well as pitch differences to reach their listener. Hence reading a frog’s response to an acoustic landscape could provide evidence about an environment and about the challenges that species face in adapting and reproducing. Much remains unknown about many other species’ hearing mechanisms, despite the fact that anthropocentric noise is a pressing reality and that it occupies significant space in the frequency spectrum.

Bodies as sensors               

 (I am an oscillatory membrane)

 The sky registers               

 What filtering organisms are accounted

 The drift of the senses         

       Where does the nonhuman lie?

I went on to speak with Jordan Karubian, a biologist researching evolutionary ecology, animal behaviour, and wetland conservation with a particular focus on birds and deforestation. Like Sidorovskaia, Karubian, too, was unaware of any soundmaps or acoustic ecology studies in Louisiana. I asked Karubian whether he has noticed any patterns among the species he studied regarding the ways they adapt to the course of present industrialisation. He responded positively. Karubian  had been surveying anthropogenic impact on ecosystems by combining genetic studies with information on how animal behaviour diversity patterns have changed over time, particularly in the case of some birds. I was particularly interested if the region’s industry left an electromagnetic imprint on the biosphere and atmosphere, thus altering species behaviour. Karubian said that swarm behaviour among birds in the Delta is an underexplored subject (with the exception of pigeon navigation that uses electromagnetic patterns). The other interviews I conducted did not offer any direct answers to this question, either.

Comparing various ecological patterns that drive evolution, Karubian studies bird species that contribute to seed dispersal and pollination. Tracking their behaviour is crucial for ecosystem conservation. Birds are critical for plant reproduction, and hence they are structurally linked to the trophic chain and oxygen metabolisation. Karubian told me that when “you do see a drop in the species that disperse the seeds, then you can see that the seeds are not being moved around as much, and then you can see that the seedlings, the next generations, are less genetically diverse and also more clustered in space.”[5] This subsequently has profound implications for the surrounding ecosystem.

Knowing how extensively industrialised the petrochemical corridor has been raises the following question: how might industrially generated sonic emissions be destabilising these seed dispersal and pollination processes and altering the region’s ecosystemic metabolism as a result? The proper concept of the river system is altered, for, if the margins of the river littoral are indeed fluctuating, as Brian Holmes predicted – not only aquatically, but also in terms of flora and fauna distribution – these are also constantly challenged by engineering implementations.[6]

I questioned Karubian how the omnipresence of industry in the region and the resulting rise in background noise might be altering species behaviour and evolutionary adaptation to engineering incursions and man-made infrastructures. According to Karubian:

Evolution is a process that in some ways that is similar to engineering. The process of evolution is one of change and refinement. In evolution, there is not this idea that things are getting better over long periods of evolutionary time but that, as environments change, life through evolution finds a way to solve problems and come to solutions. And that’s what engineers do.

One can question how aware designers and engineers are to the needs of certain species, and to the functional constraints of a given ecosystem. Hence one must account for how adaptation and evolution links back to forms of knowledge production, worldview-making, and scientific ontologies. For, if the data collected and assembled produces particular forms of accessing the world and representing it, leading to particular infrastructural implementations and engineering investments, it also generates particular forms of environmental mediation. These forms of representation, which attempt to include other entities, are often unaware, as Sidorovskaia says, of alternate forms of viewing of the world. Sensing in the dark, they often fail. To begin with, scientific methods of study and how scientists survey an ecosystem are always anthropocentric and therefore extremely partial. Science’s knowledge of other sensing systems is simply too scarce. Blind spots are endless.


Karubian referred me to associations working on restorative justice, who provide other forms of access to data monitorisation in the region. LA Bucket Brigade, an activist collective running toxic tours and awareness campaigns around the “cancer alley” did provide alternative answers. LA Bucket Brigade conducts their own air sampling tests, equipping and capacitating communities by teaching them how to interpret data. The activist collective gives communities tools to constitute their own evidence towards gaining support from political leaders and public defenders. LA Bucket Brigade had a long and eventually unsuccessful fight against the construction of the NARCO chemical plant and directed all its present campaign efforts towards halting that of the FORMOSA plant. The ways they challenge the presence of oil infrastructure in the corridor have a fierce decolonial focus. Their toxic tour covered the 1811 slave revolt path as well as it called attention to the numerous petrochemical refineries; it made the connection between forms of resistance and extraction that Louisiana has witnessed.[7] Kate McIntosh, LA Bucket Brigade member, to whom I spoke mentioned that “If people’s ancestors were able to fight slavery, we should fight petrochemicals.”[8] McIntosh also mentioned that no activist collective or self-organised community movement was looking into noise as a permanent symptom of the extractive disruption at work in the corridor. The focus was on air and toxicity.

Our conversation revealed how the ripple effects of extractive projects operate at various speeds and through many modes of presence and are subjected to different thresholds of visibility.[9] A toxic event is dispersed, slow, and often cumulative, comprising countless metabolic mutations throughout an ecosystem. These mutations often escape existing regimes of representation as they unfold at different velocities across physical dimensions in an interscalar manner. The symptoms may be already evident in some cases, as oil leaks are visible and some cancerous diagnoses easily reached. But in many other cases, the legal battle against those harmed by extraction is based on an oppressive state of distrust and benefits from the temporal gap in the causal disarrangement between the toxic event and the visible evidence of the metabolic disruption of life. This legal battle is often ocular-centric and positivistic. It prioritises what is visibly disrupted, altered, or diagnosed, marking a clear line across what is admissible as evidence. How might extraction’s toxic impacts be differentiated otherwise? Might there be other ways of narrating, disassembling, and reinterpreting the extractive event? Sound’s relational quality as an investigative tool offers clues regarding how these questions may be addressed and reformulated, while also tapping into the blind spots of existing scientific research and politics.

Challenging the threshold of visibility and the primacy of the ocular, sonic tools reveal already existing power dimensions at play before they become fully legible as symptoms of extractive dispossession. Analysing the politics of vibration, emission sources, and bandwidth use inequalities can reveal much about the colonial regime of extractive infrastructures by exposing the disassembled temporalities of the extractive event. The rise in background noise and chemical unbalance across the Lower Mississippi’s ecosystem is linked with endocrinological and immunity disruptions. The sonic is both a symptom and a tool for surveying ecosystems under distress. One could analyse bodies’ immersion in sonic networks by reflecting on different sensing processes and toxic regimes. This might be a form of the politics of the unseen and the unheard, that discloses numerous relations reassembled by the extractive event.

Why has noise as a symptom of extraction been excluded from the toxic equation for so long despite its omnipresence?


[1] Online interview conducted in October 2020.

[2] Online interview conducted in October 2020.

[3] Bernie Krause, “The Niche Hypothesis: A virtual symphony of animal sounds, the origins of musical expression and the health of habitats,” 6 June 1993, (accessed 3 August 2022).

[4] Mark Bee, “Frogs, Acoustics, and The Future of Hearing,” TEDxUMN, 19 October 2012, (accessed 3 August 2022).

[5] Excerpts from online interview conducted with Jordan Karubian in October 2020.

[6] Brian Holmes, “Check my Pulse – the Anthropocene River in Reverse,” Anthropocene Curriculum, 28 August 2020, (accessed 3 August 2022).

[7] See artist Dread Scott’s Slave Rebellion Reenactment (2019), available at

[8] Online interview conducted with Kate McIntosh on October 2020.

[9] In speaking of such ripple effects, I have in mind what Rob Nixon has called “slow violence”: endured forms of ecosystemic and social vulnerability that have been set in place by corrosive modes of capitalist extraction, disempowerment and displacement. See Rob Nixon, Slow Violence and the Environmentalism of the Poor (Cambridge, MA: Harvard University Press, 2013).

Header image

The author’s photograph documenting the River Semester journey.

About the author

Margarida Mendes is a researcher, curator, and ecologist. She creates transdisciplinary forums, exhibitions and experiential works where alternative modes of education and sensing practices may catalyse political imagination and restorative action. Mendes has been long involved in anti-extraction activism and ecopedagogy, collaborating with marine NGOs, universities, and institutions of the art world. She is a PhD candidate at the Centre for Research Architecture, Goldsmiths University of London.