The stock is best viewed as an unstructured metapopulation as defined by Hanski (1991), with a single satellite local population, although J. D. Prince (personal communication) inferred that abalone within each zone were mainly self-recruiting, resulting from the strong nexus between adult and recruit density. Variation in growth between individuals, patches, local populations, and seasonally is common, and has been variously attributed to qualities of the habitat, such as food supply (often amount of algal drift), food type, water movement, crevice abundance, as well as density of the species (Dixon and Day, 2004). The remixing and upwelling eventually bring nutrient-rich wastes back into the photic zone. This is due to the abundant solar energy which is used as a food source for primary producers such as phytoplankton. Physical factors include: temperature, hydrostatic pressure, turbulent mixing such as the upward turbulent flux of inorganic nitrogen across the nutricline. Epilithic algae grow on hard, relatively inert substrata, such as gravel, pebble, cobble, and boulder, that are bigger than most algae (see Hynes, 1970, for substratum size definitions). The

My definition of terms is not meant to be a final definition of terms, because permanent definition impedes creativity. [6] Chemical factors include oxygen and trace elements. Copyright © 2020 Elsevier B.V. or its licensors or contributors.

As the origin of marine snow lies in activities within the productive photic zone, the prevalence of marine snow changes with seasonal fluctuations in photosynthetic activity and ocean currents. There is repetitive pattern in the distribution both of individual species and of associations of species. Later reviewers concluded there was abundant (albeit circumstantial) evidence implicating light as a significant factor regulating the vertical migration of fish. Abalone were clustered mainly in crevices in patches of a size that increased with density (Shepherd and Brown, 1993; Shepherd and Partington, 1995). Several large-scale compilations of water-column unsaturation ratios have been presented (Brassell, 1993; Sikes et al., 1997; Conte et al., in press), as well as regional studies in the North Atlantic and Mediterranean (Conte et al., 1992; Conte and Eglinton, 1993; Sikes and Volkman, 1993; Ternois et al., 1997; Sicre et al., 2002).
In all cases, an exponential decrease in AQYs for DMS photolysis has been observed with increasing wavelength in the UV (Bouillon and Miller, 2004; Deal et al., 2005; Toole et al., 2003). In the photic zone, the photosynthesis rate exceeds the respiration rate.

It is the first surface where the sunlight hits the water. Almost all life on Earth relies directly or indirectly on primary production. A deep sea community is any community of organisms associated by a shared habitat in the deep sea. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae predominate in this role. Baur, in Encyclopedia of Physical Science and Technology (Third Edition), 2003. This study examines 392 samples from all major ocean basins, gathered in the mixed layer (0–30 m) to prevent including samples acquired in the seasonal thermocline, which might be falling from the warmer layer above. J.D.

Freshwater benthic algae are found in the photic zones of streams and rivers, lakes, and wetlands. Figure 5. Common use of the term benthos includes most organisms associated with substrata in aquatic habitats: fish, macroscopic invertebrates and meiofauna, fungi, bacteria, and even hyporheic (below substratum surface) organisms.