the major types of organisms found in aquatic environments are determined by
the water's salinity
salinity
the amts of various salts such as sodium chloride (NaCl) dissolved in a given volume of water
2 major types of aquatic life zones
-saltwater or marine (particularly estuaries, coastlines, coral reeds, coastal marches, mangrove swamps, and oceans)
-freshwater (particularly lakes and ponds, streams and rivers, and inland wetlands)
phytoplankton
free-floating microscopic cyanobacteria and many types of algae that are the producers supporting most aquatic food chains and webs
zooplankton
animal plankton; a mixture of 1-non-photosynthetic primary consumers that feed on phytoplankton and 2-secondary consumers that feed on other zooplankton. they range from single-celled protozoa to large invertebrates such as jellyfish
nekton
strongly swimming consumers such as fish, turtles, and whales
benthos
bottom-dwellers such as 1-barnacles and oysters that anchor themselves to one spot 2-worms that burrow into the sand or mud 3-lobsters and crabs that walk about on the bottom; some of these species get food by filtering it from water
decomposers
mostly bacteria that break down the organic compounds in the dead bodies and wastes of aquatic organisms into simple nutrient compound for use by producers
aquatic systems have less pronounced and fixed ___ ___ than terrestrial ecosystems. this makes it difficult to ___ and ____ ___ of aquatic organisms
physical boundaries; count; manage populations
aquatic systems have more complex and longer __ __ and ___ ___ than most terrestrial. one reason is that the fluid medium of water systems and the variety of ___ habitats open up ways of getting good that are not available on land
food chains; food webs; bottom
most aquatic life zones are divided into 3 layers
surface, middle, bottom
important environmental factors determining the types and numbers of organisms found in layers of aquatic life zones are what? (4)
1-temperature 2-access to sunlight for photosynthesis 3-dissolved oxygen content 4-availability of nutrients such as carbon, nitrogen and phosphorus for producers
euphotic zone
upper layer of deep aquatic systems through which sunlight can penetrate. the depth can be reduced by excessive algal growth that make water cloudy
O2 enters an aquatic stsem from the atmosphere and therough photosynthesis by aquatic producers and is removed by ___ ____ of producers, consumers, and decomposers
aerobic respiration
CO2 enters an aquatic system from the atmosphere and through aerobic respiration by producers, consumers, and decomposers and i removed by _____ ___
photosynthesizing producers
the amount of oxygen dissolved in water can vary widely, depending on what 4 factors?
1- temperature 2- number of producers 3-number of consumers and aerobic decomposers 4- deep ocean circulation which can cause oxygen-saturated surface water in some areas to sink and spread)
in the open ocean, nitrates, phosphates, iron, and other nutrients often are in short supply and limit ___ ____ ____
net primary productivity
saltwater oceans over about __% of the planet's surface; __% of the world's habitable volume; contains ___ known species of marine plants and animals, and provide many important ___ and ___ services
71; 99.5%; 250000; ecological; economic
coastal zone
the warm, nutrient-rich, shallow water that extend from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf. contains 90% of all marine species
continental shelf
the submerged part of the continents
most ecosystems found in the coastal zone have a very high net primary productivity per unit of area b/c (2)
ample supplies of 1-sunlight 2-plant nutrients (flowing from land and distributed by wind and ocean currents)
estuary
a partially enclosed area of coastal water where seawater mixes with fresh water and nutrients from rivers, streams, and runoff from land. it is a ecotone between the marine environment and the land where large volumes of fresh water from land and salty o
coastal wetlands
land areas covered with water all or part of the year
estuaries and their coastal wetlands include 6 things
1-river mouth 2-inlets 3-bays 4-sounds 5-mangrove forest swamps in tropical waters 6- salt marshes in temperate zones
intertidal zone
the area of shoreline between low and high tides. species must be about to avoid being 1-swept away or crushed by waves 2- immersed during high tides 3-left high and dry at low tides
barrier islands
long, thin, low offshore islands of sediment that generally run parallel to the shore. found along some coasts such as most of North America's Atlantic and Gulf coasts.
what do barrier islands help protest?
the mainland, estuaries and coastal wetlands by dispersing the energy of approaching storm waves
coastal reefs
form in clear, warm coastal waters of the tropics and subtropics. most diverse and productive ecosystems
3 main organisms of coral reefs
1- attached organisms (corals, algae, and sponges) 2-fishes 3- small organisms that bore into, attach to, or hide within a reef's many nooks and crannies
coral reefs are vulnerable b/c they... (3)
1-grow slowly 2- are disrupted easily 3-thrive only in clear, warm and fairly shallow water of constant high salinity
open sea
the sharp increase in water depth at the edge of the continental shelf separates the coastal zone from the vast volume of the ocean
3 vertical zones of open sea
1-euphotic zone 2-bathyal zone 3- abyssal zone
euphotic zone
the lighted upper zone where 1-photosynthesis occurs mostly by phytoplankton 2-nutrient lvs are low 3-levels of dissolved oxygen. large, fast-swimming predatory dish
bathyal zone
dimly lit middle zone that does not contain photosynthesizing producers b/c of a lack of sunlight. various types of zooplankton and smaller dish, many of which migrate to feed on the surface at night, populate this zone
abyssal zone
dark lower zone that is 1-very cold 2- has little dissolved oxygen 3- has enough nutrients on the ocean floor to support about 98% of the 250,000 identified species living in the ocean
deposit feeders
take mud into their guts and extract nutrients from it
filter feeders
oysters and mussels; pass water through or over their bodies and extract nutrients from it
average primary productivity and NPP per unit of area are ____ in the open sea
quite low
salt marshes, mangrove forest, and sea-grass meadows (sea's 3 great marine nurseries) are being lost and degraded at a high rate to make way for ___ ___ ___, ___, ___ ___, and __ __
real estate development, marinas, golf courses, and shrimp farms
the world's remaining coastal wetlands is likely to be lost to 3
1- agriculture 2-urban development 3-rising sea levels from climate change
freshwater life zones
occur where water with a dissolved salt concentration of less than 1& per volume accumulates on or flows through the surfaces of terrestrial biomes
standing (lentic) bodies of water
lakes, ponds, and inland wetlands
flowing (lotic) systems
streams and rivers
lakes
large natural bodies of standing fresh water formed when precipitation, runoff, or groundwater seepage fills depressions in the earth's surface
littoral zone
consists of the shallow sunlit waters near the shore to the depth at which rooted plants stop growing. high biological diversity
limnetic zone
the open, sunlit water sruface later away from the shore that extends to the depth layer away from the shore that extends to the depth penetrated by sunlight.
profundal zone
the deep, open water where it is too dark for photosynthesis. w/o sunlight and plants, oxygen levels are low. fish adapted to its cooler and darker water are found in this zone
benthic zone
at the bottom of the lake. it is inhabited mostly by organisms that tolerate cool temperatures and low oxygen levels
oliotrophic lake
a newly formed lake generally has a small supply of plant nutrients. deep with steep banks. low NPP. crystal-clear blue or green and small population of phytoplankton and dish
eutropic lake
a lake with a large or excessive supply of nutrients needed by producers. are typically shallow and have murky brown or green water with very poor visibility. high NPP
epilimnion
an upper layer of warm water with high levels of dissolved oxygen
thermocline
where the water temperature changes rapidly with depth and with moderate levels of dissolved oxygen
hypolimnoin
a lower layer of colder, denser water, usually with a lower concentration of dissolved oxygen b/c it is not exposed to the atmosphere. during the summer the thermocline acts as a barrier preventing the transfer of nutrients and dissolved oxygen between th
fall overturn
brings nutrients from bottom sediments to the surface, brings dissolved oxygen from the surface to the bottom, and allows fish to live at various depths
spring overturn
the temperature of the lake and dissolved oxygen levels are roughly the same at all depths
surface water
precipitation that does not sink into the ground or evaporate
runoff
surface water that flows into streams
watershed/drainage basin
the land area that delivers runoff, sediment, and dissolved substances to a stream
source zone
headwater or mountain highland streams of cold, clear water rush over waterfalls and rapids.
transition zone
the headwater streams merge to form wider, deeper streams that flow down gentler slopes with fewer obstacles. the warmer water and other conditions in this zone support more producers and a variety of cool-water and warm-water dish species with slightly l
floodplain zone
streams join into wider and deeper rivers that meander across broad, flat valleys. water in this zone usually has higher temperatures and less dissolved oxygen than water in the first two zones
inland wetlands
lands covered with fresh water all or part of the time and located away from coastal areas
inland wetlands include (6)
1-marshes with few trees 2-swamps dominated by trees and shrubs 3-prairie potholes (depressions carved out by glaciers) 4-flood plains (receive excess water during heavy rains and floods) 5- bogs and fens that have waterlogged soils which tend to accumula
seasonal wetlands
wetlands that are underwater or soggy only a short time each year.
structure or spatial distribution in terms of 4 characteristics
1- physical appearances 2-species diversity or richness 3-species abundance 4-niche structure
4 characteristics that ecologists use to describe
physical appearance, species diversity/richness, species abundance and niche structure
physical appearance
relative size, stratification, and distribution of its population and size.
species diversity/richness
the number of different species
species abundance
the number of individuals of each species
niche structure
the number of ecological niches, how they resemble or differ from each other and how they interact