Published: 6 July 2026
Author: Dr Mark Hartl

Marine ecotoxicology is the study of identifying exposure of marine organisms to pollutants, such as metals, and measuring changes to the organism's physiology, so called biomarker endpoints. Marine ecotoxicology is well-developed in coastal environments but the results are not necessarily transferable to the deep-sea and need to be optimised for deep-sea organisms, a vital process if we are to fully understand human impacts in the deep.

There is a need to establish baselines for commonly used biomarker endpoints so that the situation before a disturbance is known, enabling us to quantify the impact.

In situ data, i.e., on the seafloor at several thousand meters depth are rare and non-existent for fish.

One of the aims of JC257 was to explore and test procedures for establishing in situ baselines for a variety of ecotoxicological endpoints, DNA damage (see blog from JC241) and oxidative stress in fish.

Oxidative stress is an imbalance between oxygen radicals and antioxidants (e.g. vitamins etc) in the cells of organisms living in the deep-sea. Relevant endpoints include various antioxidant enzymes and cell membrane damage.

SMARTEX and JC257 offered the exciting opportunity to work together with the ISIS ROV team to operate a fish trap in situ and explore how sediment plumes might impact the species living there.

ROV screenshotROV screenshot

It was very exciting to be sitting in the ISIS ROV van directing the operation of the manipulator arm to close the trap and create an experimental plume.

ROV control room

This work is essential to help us refine these procedures so that they are not just feasible but the resulting data ecologically meaningful for making future regulatory decisions concerning the exploitation of the deep-sea.

Get Involved

Be part of the community helping our ocean thrive.


Donate to NOC
Get in touch
Topography pattern
Author

Dr Mark Hartl

Associate Professor of Marine Biology, Heriot-Watt University

Dr Hartl is an Associate Professor of Marine Biology, specialising in Marine Ecotoxicology in the Centre for Marine Biodiversity & Biotechnology (CMBB), Institute of Life and Earth Sciences, at Heriot-Watt University. He is also Director of the CMBB and Director of Studies for the MSc cluster in Marine, Environment and Climate Change.

More Blogs

Image of biodiversity captured on JC257

JC257: Imaging the Abyss

7 March 2024
Ophiuroid

JC257: Bathy-Snaps

6 March 2024
Ophiuroid

JC257: Muddled By Mud

1 March 2024
Tanga Morris looking at the sunset

JC257: Mei Te Kuki Airani Ki James Cook / From the Cook Islands to the James Cook

1 March 2024