Nutrient-poor environment (IUCN, 2012a).

From an ecological point of view, old-growth forests are a stage of forest development characterized by large/old trees and structural complexity including live and dead trees, and vertical and horizontal heterogeneity (including a multi-layered canopy). The structural diversity of old growth forests often supports distinctive/specialist biodiversity; large/old trees are keystone components of the ecosystem (Lindenmayer et al., 2012). In addition, the long-period of forest development without stand replacement disturbance allows many poor-dispersing species to accumulate (IUFRO, 2018).

An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution.

Oxygen-deficient layers in the ocean water column. OMZs correspond to subsurface oceanic zones reaching ultra-low values of O2 concentration (Paulmier & Ruiz-Pino, 2008).

Large system of rotating ocean currents. There are five major gyres: the North and South Pacific Subtropical Gyres, the North and South Atlantic Subtropical Gyres, and the Indian Ocean Subtropical Gyre (NOAA, 2018c).

Observing is defined as a non-extractive practice that is based on the observation of wild species. The observation can imply some interaction with the wild species, such as the activities of wildlife tourism and whale watching or no interaction with the wild species, such as photography.

The processes by which elements are extracted from their mineral, aquatic, or atmospheric sources or recycled from their organic forms, converting them to the ionic form in which biotic uptake occurs and ultimately returning them to the atmosphere, water, or soil.

A repeated pathway of a particular nutrient or element from the environment through one or more organisms and back to the environment. Examples include the carbon cycle, the nitrogen cycle and the phosphorus cycle.

Nutrients that can be extracted by plant roots, generally from the soil (Silver, 1994).

A generic term for the nitrogen oxides most relevant for air pollution (NO and NO2) (Omidvarborna et al., 2015).