# A Ship Grounding Over a Century Ago Left a Lasting Channel Among Corals

## TL;DR

A shipwreck over 100 years ago in Brazil caused lasting damage to a coral reef, with no sign of recovery.

## Contribution

The study shows that some coral reefs may not recover from ship groundings for over a century.

## Key findings

- A 100+ year old ship grounding created a semi-permanent sand channel in a coral reef.
- The reef has not shown signs of returning to its pre-disturbance state.
- Acute disturbances like ship groundings can cause long-term structural changes in coral ecosystems.

## Abstract

Among disturbance events to coral reef ecosystems, ship groundings can be among the most acute due to the physical damage they cause to coral reef habitats. Following ship groundings, monitoring studies show that some reefs recover whereas others retain changes in coral community structure for at least a decade. Thus, the recovery timescales following groundings are variable, but the general paradigm is that reef communities will begin on a trajectory toward recovery to the pre‐disturbance state. Here, we report several lines of evidence of a 100+ year old ship grounding in northeastern Brazil. Strikingly, the ship grounding led to a semi‐permanent sand channel in the reef that has not substantially trended toward recovery. Our observations support the notion that acute disturbance on coral reefs can cause structural changes that may never return to the pre‐disturbance conditions.

Ship groundings damage coral ecosystems due to the physical abrasion or shattering of corals, but also lead to changes in community structure and increases in coral diseases. In northeastern Brazil, the state of Rio Grande do Norte has a notable history of shipwrecks and maritime incidents due to the combination of strong trade winds, complex currents, and shallow coral reefs. We observed what appears to be a sand channel cut through a coral community by a ship grounding more than 100 years ago in the parrachos of Rio do Fogo.