Layers of mud are building up at a pace of about a millimeter per year somewhere beneath the warm blue-green water of the Gulf of Mexico, a few thousand meters below the surface, in the never-ending darkness where no sunshine has ever reached. This is something they have been doing for a very long time.
The shells of microscopic organisms known as foraminifera, whose chemical makeup records the temperature of the water they inhabited, plant matter carrying isotopic signatures of rainfall and river runoff from the nearby land, and coarser sediment layers that were abruptly deposited when a hurricane passed overhead and disturbed the seafloor are all captured by each layer. It is a library in the strictest meaning of the word. For decades, scientists have been drilling into it, extracting sediment cylinders known as cores, and using layers no thicker than a credit card to decipher the climate history of the past several centuries.
Because the Gulf of Mexico is a semi-enclosed basin with distinctive oceanographic characteristics that enhance climate signals, the deep-sea sediment record there is very valuable for climate study. Here, variations in Atlantic circulation and the heat content of the deep water passing through the Gulf’s interior have a sensitive effect on sea surface temperatures. The sediment accurately captures this sensitivity, resulting in temperature reconstructions that go much beyond the roughly 170 years of systematic observational measurement into times when climate circumstances were different in ways that models are still trying to accurately describe.
Gulf cores have been used to follow the shutdown and restart of deep-water circulation patterns, reconstruct the frequency of hurricanes throughout previous centuries, and record the rate at which the ecosystem responded to previous warm intervals. The information is truly unique. This type of continuous high-resolution record is not available anywhere else.
The Gulf is the most heavily developed offshore oil and gas basin in the United States, with a network of pipelines, wellheads, and production platforms covering its floor in a manner unmatched by any other ocean region. The controversy surrounding drilling for it is inextricably linked to this. The physical process of coring is less intrusive than production drilling, so scientific sediment coring and industrial hydrocarbon extraction are not directly competing activities.
However, they share a geography, a permitting structure, and a set of ecological stakes that inevitably cause friction. The regulatory frameworks controlling such activities weren’t always intended to function well together when BOEM issued a research coring permit in the same area where it also manages current oil leases. Furthermore, the recollection of what transpires in this region when anything goes wrong is quite particular and fresh.
Over the course of 87 days, the Deepwater Horizon accident in April 2010 released over 4.9 million barrels of oil, contaminating deep-water sediment communities in a wide area surrounding the wellsite. More than ten years later, deep-sea coral ecosystems continued to exhibit quantifiable impact, according to research released in the years that followed. In addition to causing immediate harm, the incident altered scientists’ and regulators’ perceptions of the deep Gulf as an ecosystem.
Prior to April 2010, there existed a different understanding of the fragility of the benthic communities that inhabit the sediment on which the scientific record itself is partially written. Even with scientific rather than industrial equipment, there is a chance that drilling into the climate archive will disrupt the surrounding environment.
A layer of ecological and legal complexity is introduced by the Rice’s whale. The distribution of this severely endangered species, which has fewer than 100 individuals left, directly crosses over into the deep Gulf areas where research and industrial drilling is most prevalent. The Endangered Species Act’s consultation procedures are triggered by any increase of offshore operations in specified areas, which can complicate and slow the approval process for research that could have otherwise gone quite quickly.
It’s also uncertain if the current regulatory instruments are adequate to safeguard whales while permitting sediment science to advance at the rate that climate scientists contend is essential. There is something genuinely unsettling about the situation that scientists find themselves in when they watch these conflicting pressures play out in the same body of water: they are dependent on an environment that they are also asking to bear more human presence than it has historically been asked to bear.
