biologia: Ocean

Evidence: 82 • authority: 72

The mesopelagic zone (Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light, and begins at the depth where only 1% of incident light reaches and ends where there is no light; depth ranges from approximately 200 to 1,000 meters (660 to 3,280 ft) below the ocean surface. It is largely nutrient-rich in comparison to the euphotic zone, making the biogeochemical processes of the mesopelagic particularly important to nutrient cycling in the ocean. The mesopelagic zone occupies about 60% of the planet's surface and about 20% of the ocean's volume, co…

Evidence: 45 • authority: 92

Darkening of the Global Ocean.. The photic zones of the oceans-where sunlight and moonlight drive ecological interactions-are one of the most productive habitats on the planet and fundamental to the maintenance of healthy global biogeochemical cycles. Ocean darkening occurs when changes in the optical properties of the oceans reduce the depth to which sufficient light penetrates to facilitate biological processes guided by sunlight and moonlight. We analysed a 9 km resolution annual time series of MODIS Aqua's diffuse attenuation coefficient of light at 490 nm [K d (490)] to quantify whether the oceans have darkened over the last 20 years and the impact of this on the depth of photic zones…

Evidence: 43 • authority: 92

Redefining the photic zone: beyond the autotroph-centric view of light in the ocean.. Traditional measures of the photic zone have remained focused on autotrophs, limiting understanding of how changing marine lightscapes impact heterotrophs that use light as a resource or an environmental cue. We propose a new photic zone definition that encompasses all biological processes influenced by celestial light, and a new measure of photic zone depth, the minimum light intensity that elicits biological responses. This approach allows photic zone measures to be inclusive of all marine photobiology driven by sunlight, moonlight, or starlight, and enables urgently needed exploration of the nature, ext…

Evidence: 43 • authority: 72

The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of 1,000 to 4,000 m (3,300 to 13,000 ft) below the ocean surface. It lies between the mesopelagic above and the abyssopelagic below. The bathypelagic is also known as the midnight zone because of the lack of sunlight; this feature does not allow for photosynthesis-driven primary production, preventing growth of phytoplankton or aquatic plants. Although larger by volume than the photic zone, human knowledge of the bathypelagic zone remains limited by ability to explore the deep ocean.

Evidence: 36 • authority: 72

The littoral zone, also called litoral or nearshore, is the part of an ocean, sea, lake, or river, that is close to the shore. It provides extensive and productive habitats around the world, adjacent to land-water interfaces. In coastal ecology, the littoral zone includes the foreshore (intertidal zone) extending from the high water mark (which is rarely inundated) to the low water mark (where coastal areas become permanently submerged). However, the geographical meaning of littoral zone extends well beyond the intertidal zone to include all neritic waters within the bounds of continental shelves. Continental shelves cover an area of about 7% of the surface area of the oceans. In lake ecosy…

Evidence: 29 • authority: 92

Physical controls on heterogeneous mesopelagic biogeochemistry.. The surface and interior ocean are connected through physical processes that act in three dimensions and on subseasonal timescales. Numerical models and observations both highlight the importance of these eddying dynamics on shaping the biogeochemical and biological variability in the upper mesopelagic ocean. The resulting subsurface tracer variance outside of the photic zone has implications for ocean ventilation timescales as well as biogeochemical function and microbial community composition. Subsurface patchiness is best described using water mass frameworks that account for the dynamic processes that drive the transport o…

Evidence: 29 • authority: 72

The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological processes that supply nutrients into the upper water column. The photic zone is home to the majority of aquatic life due to the activity (primary production) of the phytoplankton. The thicknesses of the photic and euphotic zones vary with the intensity of sunlight as a function of season and latitude and with the degree of water turbidity. The bottommost, or aphotic, zone is the region of perpetual darkness that lies beneath the photic zone and incl…

Evidence: 21 • authority: 80

On the particle-water partitioning of PCBs in the photic zone: A 25-month study in the open Baltic Sea

Evidence: 21 • authority: 88

Molecular ecology of eukaryotic symbioses in the planktonic ecosystems of the oceanic photic zone. Écologie moléculaire des symbioses eucaryotes des écosystèmes planctoniques de la zone photique des océans Les symbioses ont un role majeur dans le fonctionnement et l'equilibre des ecosystemes. Dans les oceans, qui couvrent pres de 70 % de la surface de la planete, vivent une multitude d'organismes incapables de lutter contre les courants et la plupart sont microscopiques, il s'agit du plancton. Les organismes du plancton, comme ceux d'autres ecosystemes, entretiennent des symbioses, mais la nature et l'ampleur de ces interactions sont encore mal connues dans le plancton du fait la petite tai…

Evidence: 21 • authority: 72

The hadal zone, also known as the hadopelagic zone or hadalpelagic zone, is the deepest region of the ocean, lying within oceanic trenches. The hadal zone ranges from around 6 to 11 km (3.7 to 6.8 mi; 20,000 to 36,000 ft) below sea level, and exists in long, narrow, topographic V-shaped depressions. The total area is taken up by the 46 individual hadal habitats worldwide is less than 0.25% of the world's seafloor, yet trenches account for over 40% of the ocean's depth range. Most hadal habitats are found in the Pacific Ocean, the largest and deepest of the conventional oceanic divisions.

Evidence: — • authority: 65