Stress ecology

Within the field of global change biology, the multifactorial nature of environmental change is a major obstacle to develop robust predictions about biological responses to global change. In marine ecosystems worldwide, organisms are experiencing environmental changes such as:

• Increased water temperatures
• Decreased pH
• Increased pollution with chemicals
• Changes in salinity caused by altered freshwater inputs
• Lowered oxygen availability

Ecological and physiological responses to stressors

Stress in aquatic animals occurs due to physical and physiological disturbances in their environment when transportation, crowding, handling or changes in physical and chemical factors take place. There are three regulatory systems that play a vital role in stress response, more specifically the neural, the endocrine and the immune system. For aquaculture species, the main stressors are handling, food supply and changes in temperature and oxygen. These factors can cause:

• Differences in texture and taste
• Lower performance
• Reduced feeding

In addition to individual responses, also biological communities are exposed to an array of environmental conditions that, when exceeding physiological tolerance limits, cause stress and affect the performance of sensitive species. As such, species- and strain-specific responses to stressors, along with antagonistic (e.g. competition) and synergistic (e.g. facilitation) biotic interactions, shape community structure and biodiversity. Understanding stress responses in the context of biotic interactions is thus essential to understand community biodiversity.

Services

• Experiments to test for stress effects, facilities to apply reduced oxygen, reduced pH, temperature control
• Biochemical profiling (fatty acids) of marine invertebrates in a context of stress ecology, both in the field as in experimental setups and in aquaculture installations

Applications

• Linking food web ecology and stress ecology
• Global change biology at different levels of organization (from cellular level to community composition)
• Optimalisation of food assimilation and energy flow in relation to aquaculture rearing conditions and potential stress factors

Example

Change of assimilation of food by marine invertebrates under different temperatures (see Werbrouck et al., 2016 a, b) will have an effect on the overall flow of energy in marine food webs.