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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Benthic zone | 5/5 | https://en.wikipedia.org/wiki/Benthic_zone | reference | science, encyclopedia | 2026-05-05T07:34:28.462475+00:00 | kb-cron |
Benthic macroinvertebrates have many important ecological functions, such as regulating the flow of materials and energy in river ecosystems through their food web linkages. Because of this correlation between flow of energy and nutrients, benthic macroinvertebrates have the ability to influence food resources on fish and other organisms in aquatic ecosystems. For example, the addition of a moderate amount of nutrients to a river over the course of several years resulted in increases in invertebrate richness, abundance, and biomass. These in turn resulted in increased food resources for native species of fish with insignificant alteration of the macroinvertebrate community structure and trophic pathways. The presence of macroinvertebrates such as Amphipoda also affect the dominance of certain types of algae in Benthic ecosystems as well. In addition, because benthic zones are influenced by the flow of dead organic material, there have been studies conducted on the relationship between stream and river water flows and the resulting effects on the benthic zone. Low flow events show a restriction in nutrient transport from benthic substrates to food webs, and caused a decrease in benthic macroinvertebrate biomass, which lead to the disappearance of food sources into the substrate. Because the benthic system regulates energy in aquatic ecosystems, studies have been made of the mechanisms of the benthic zone in order to better understand the ecosystem. Benthic diatoms have been used by the European Union's Water Framework Directive (WFD) to establish ecological quality ratios that determined the ecological status of lakes in the UK. Beginning research is being made on benthic assemblages to see if they can be used as indicators of healthy aquatic ecosystems. Benthic assemblages in urbanized coastal regions are not functionally equivalent to benthic assemblages in untouched regions. Ecologists are attempting to understand the relationship between heterogeneity and maintaining biodiversity in aquatic ecosystems. Benthic algae has been used as an inherently good subject for studying short term changes and community responses to heterogeneous conditions in streams. Understanding the potential mechanisms involving benthic periphyton and the effects on heterogeneity within a stream may provide a better understanding of the structure and function of stream ecosystems. Periphyton populations suffer from high natural spatial variability while difficult accessibility simultaneously limits the practicable number of samples that can be taken. Targeting periphyton locations which are known to provide reliable samples – especially hard surfaces – is recommended in the European Union benthic monitoring program (by Kelly 1998 for the United Kingdom then in the EU and for the EU as a whole by CEN 2003 and CEN 2004) and in some United States programs (by Moulton et al. 2002). Benthic gross primary production (GPP) may be important in maintaining biodiversity hotspots in littoral zones in large lake ecosystems. However, the relative contributions of benthic habitats within specific ecosystems are poorly explored and more research is planned.
== Threats and mitigation ==
Benthos are negatively impacted by fishing, pollution and litter, deep-sea mining, oil and gas activities, tourism, shipping, invasive species, climate change (and its impacts such as ocean acidification, ocean warming and changes to ocean circulation) and construction such as coastal development, undersea cables, and wind farm construction.
Bottom trawling accounts for roughly 25% of global capture fisheries. It has increasingly been recognized as a non-sustainable fishing practice. It impacts benthic ecosystems in two ways. First, fishing gear disrupts epibenthic sediments, resulting in the loss of habitat complexity and resuspension of sediments into the water column, reducing the sedimentary organic-matter content, and increasing turbidity and biochemical oxygen demand in the water column. Second, trawling disrupts benthic community structure, selectively removing large-bodied target and non-target species, which are usually K-selected, resulting in a community dominated by relatively small r-selected species. Given the significance of these impacts, a number of countries have implemented total or partial bans on bottom trawling within their territorial waters or in the international waters they manage.
== See also ==
== References ==
== External links ==
Data Archive for Seabed Species and Habitats from the UK Marine Data Archive Centre "Benthos" "Benthos". (2008) Encyclopædia Britannica. (Retrieved May 15, 2008, from Encyclopædia Britannica Online.) Ryan, Paddy (2007) "Benthic communities" Archived 2008-12-16 at the Wayback Machine Te Ara - the Encyclopædia of New Zealand, updated 21 September 2007. Yip, Maricela and Madl, Pierre (1999) "Benthos" Archived 2019-07-20 at the Wayback Machine University of Salzburg.