CO3_Lake ecology.pptx

Aries Paul D. Padron 🞂 ​Limnology is the study of inland waters - lakes (both freshwater and saline), reservoirs, rivers, streams, wetlands, and groundwater - as ecological systems interacting with their drainage basins and the atmosphere. 🞂 🞂 ​ Freshwater 🞂 ​ Lake 🞂 ​ Pond 🞂 ​ River 🞂 ​ Swam...

Aries Paul D. Padron 🞂 ​Limnology is the study of inland waters - lakes (both freshwater and saline), reservoirs, rivers, streams, wetlands, and groundwater - as ecological systems interacting with their drainage basins and the atmosphere. 🞂 🞂 ​ Freshwater 🞂 ​ Lake 🞂 ​ Pond 🞂 ​ River 🞂 ​ Swamp 🞂 ​ Marsh 🞂 ​ Bog 🞂 ​ Fen Environment 🞂 ​1. Lotic - running water series (ex. river) - continuous and with a definite direction. Sequence: 🞂 ​2. Lenticstanding brook water creek river series � Sequence: lake,pond, � swamp is a body of water occupied in a basin and lacking continuity with the sea. It has a considerable area and deep enough to stratify. 🞂 ​Lake 🞂 Pond is a small shallow body of water either formed through depression or man-made. 🞂​ 🞂 is a type of wetland that is dominated by herbaceous rather than woody plant species. Marshes can often be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems. They are often dominated by grasses, rushes or reeds. 🞂 ​Marsh 🞂 is a wetland that is forested. Many swamps occur along large rivers, where they are critically dependent upon natural water level fluctuations. Other swamps occur on the shores of large lakes. 🞂 ​Bog is a wetland that accumulates peat, a deposit of dead plant material—often mosses. , and in a majority of cases, Sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, quagmire and muskeg. 🞂 ​Swamp 🞂 ​Fen is one of the four main types of wetland, and is usually fed by mineral-rich surface water or groundwater. 🞂 ​Fens are characterized by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nurients. They are usually dominated by grasses and sedges, and typically have brown mosses in general Ecology – is the study of the lake’s biotic and abiotic interaction/relationship. 🞂 ​Lake lake -lake formed by glaciers. Ex. Pingo lake 🞂 ​Glacial ​ Tectonic lake- Lake formed by movements of the earth’s crust ◦ Graben lakes – formed between faults and adjacent highlands. ◦ Ex. Lake Baikal of Siberia – deepest lake in the world, Lake Tahoff – California, Lake Tanganyika – East Africa, 2nd deepest lake. ◦ Uplift lakes – result of epeirogenesis 🞄 Epeirogenesis – wide reaching tectonic events that raise large crustal blocks and sometimes bring about the formation of enormous basins. Ex. Caspian Sea ◦ Earthquake lakes – water is spilled through a series of earthquake events forming lakes. Ex. Reelfoot lake – United States - spilled from the Mississippi River. Lake Baikal Caspian Sea Lake Tanganyika Reelfoot Lake ​ Landslide lakes – formed from the impoundment of stream valleys by rock slides, mud floods and other mass movements of rocks. 🞂 ​Volcanic lake- formed through volcanic actions. ◦ Crater lake- Lakes formed by volcanoes. ◦ Lava lake- formed by lava depression ◦ Caulee lake – magma hardened and formed a basin. lake- Where ice sheets move over relatively flat surfaces of hard jointed or fractured rock, hollow basins are formed and subsequently filled with water 🞂 ​Solution lakes – lakes in carbonic substrates (lakes in salt collapsy bases) 🞂 ​Ice-scour lake – formed due to the erosive force of the wind. 🞂 ​Aeolian 🞂 ​Fluviatile lakes – formed by founding of deltas. ◦ Levee lakes – shallow, elongate, parallel to stream ◦ Oxbow lakes – formed by isolated loops of meandering mature streams 🞂 lakes – formed by wave actions in the shoreline. Ex. Beach pools 🞂 ​Lake basins impounded or excavated by organisms. Ex. Beaver 🞂 ​Shoreline Maximum Depth (M ) 2 🞂 🞂 Lake Surface Area (Km2) Superior (America) 83,300 63,800 🞂 Victoria (Africa) 59,510 🞂 Huron 57,850 🞂 Michigan 34,000 🞂 Tanganyika (Africa) 🞂 ​ Baikal (Siberia, Russia and China) 730 30,800 🞂 Malawi (Africa) 🞂 Erie (Canada) 25,820 24,530 🞂 Winnipeg 18,760 🞂 Ontario 31,500 307 79 223 265 572 273 64 19 225 🞂 🞂 🞂 🞂 🞂 🞂 🞂 🞂 🞂 🞂 🞂 Laguna de Bay Lanao Taal Mainit Naiyan Buluan Bato Pagusi Laabas Lumo Buhi 89,076.30 33,999.70 24,356.40 17,430.20 7,899.50 6,134.20 3,792.50 2,531.50 2,140.80 1,192.00 1,105.80 🞂 ​The lake is divided into different “zones” determined by depth and distance from the shoreline 🞂 ​littoral zone 🞂 ​limnetic zone 🞂 ​profundal zone 🞂 ​Photic zone 🞂 ​Benthic zone zone- the shallow and warmest zone of the lake. 🞂 ​Littoral ◦ It sustains a fairly diverse community (several species of algae (like diatoms) , rooted and floating aquatic plants, grazing snails, Clams, Insects, Crustaceans, Fishes and amphibians) ◦ subject to fluctuating temperature and erosion of shore materials through wave actions sediment is coarse ◦ unprotected shores, shallow water depth, well lighted, it’s a bond from shoreline to the depth where aquatic plants disappear wave action is extreme zone- near-surface open water surrounded by the littoral zone 🞂 ​Limnetic ◦ well-lighted (like the littoral zone) and is dominated by plankton, both phytoplankton and zooplankton ◦ plankton are small organisms that play a crucial role in the food chain – most life would not be withoutsynthesis them � possible Trophogenicof organic carbon of freshwater fish also occupy this zone � ◦ variety occurs ◦ it is where theby trophogenic zone occurs largely defined the epilimnion zone – cold and dense region of the lake. It is also called as the aphotic zone where light is reduced. 🞂 ​Profundal ◦ current minimum ◦ temperature nearly uniform ◦ oxygen scanty, depleted ◦ methane and carbon dioxide abundant ◦ hydrogen concentration is high because of the presence of carbonic acid. ◦ decomposing, decaying matter ◦ found in the hypolimnion ◦ sediments are fine particles ◦ benthic organisms dominate 🞂 ​ Photic zone- lighted zone of the lake 🞂 🞂 ​ Primary production in the photic zone is influenced by three major factors ◦ Nutrients ◦ Light- For photosynthesis ◦ Grazing pressure -the rate at which the plants are eaten by herbivores. 🞂 🞂 ​ Nutrients especially phosphate and nitrate, are often scarce in the photic zone because they are used up quickly by plants during photosynthesis. 🞂 ​ External inputs of nutrients are received through: ◦ ◦ ◦ ◦ Rainfall River flow Weathering of rocks and soil Human activities- sewage dumping 🞂 ​Benthic zone- bottom area of the lake. 🞂 ◦ Many groups and varieties of animals live here, a few are worms, crustaceans, and protozoa. ◦ The life in this zone is mostly made up of bottom dwellers which get most of their food from dead and decaying organisms. ◦ most of the organisms in the benthic zone are scavengers because they depend on dead flesh as their main food source. ◦ Organisms here tend to tolerate cooler temperatures well. ◦ Place where decomposition takes place. ◦ For the profundal and benthic zones, low levels of photosynthesis result in low levels of dissolved oxygen 🞂 ​Oligotrophic- poor nutrient 🞂 ​Mesotrophic- middle/intermediate 🞂 ​Eutrophic – high nutrient 🞂 ​Water is clear and appears blue to blue green in the sunlight 🞂 ​The nutrient content in the water is low; and although nitrogen is abundant, phosphorus is highly limited 🞂 ​Low production of organic mater, particularly phytoplankton 🞂 ​Oxygen concentration remains high 🞂 ​Free of weeds or large algae blooms 🞂 ​Can have some large game fish, but small populations 🞂 ​No food for bacteria 🞂 ​Sandy, rocky bottom 🞂 🞂 ​Lakes that receive large amounts of organic matter from surrounding lands particularly in the form of humic materials that stain the water brown 🞂 ​ Low only in planktonic vegetation but have generally high productive littoral zones 🞂 ​Littoral vegetation dominates the metabolism of the lake, providing a source of both dissolved and particulate organic matter 🞂 ​ Some organic sediment accumulating 🞂 ​ Some loss of oxygen in the lower waters 🞂 ​High productivity 🞂 ​High depth of organic sediment 🞂 ​associated with high nitrogen and phosphorus 🞂 ​increase in growth of algae and other aquatic plants. 🞂 ​May experience oxygen depletion– Anoxic lower layer an upper layer of circulating warm water, usually no more than 6 m (20 ft) deep, where dissolved oxygen concentrations are moderate to high. 🞂 ​Metalimnion or thermoclinea layer of rapid temperature and oxygen decrease with depth, often quite thin, separating the upper and lower layers. 🞂 ​Hypolimnion – a cold, deep-water, noncirculating layer in which oxygen is low or absent. 🞂 ​Epilimnion- 🞂 ​The top-most layer in a thermally stratified lake. 🞂 ​It is warmer and typically has a higher pH and dissolved oxygen concentration than the hypolimnion. 🞂 ​It typically mixed as a result of surface windmixing. 🞂 ​Free to exchange dissolved gases (ie O2 and CO2) with the atmosphere. 🞂 ​It contains the most phytoplankton 🞂 🞂 ​ Temperature changes more rapidly with depth than it does in the layers above or below. 🞂 ​ Thermoclines may be a semi-permanent feature of the body of water in which they occur, or they may form temporarily in response to phenomena such as the radiative heating/cooling of surface water during the day/night. 🞂 ​ Factors that affect the depth and thickness of a thermocline include seasonal weather variations, latitude, and local environmental conditions, such as tides and currents. 🞂 ​Typically the hypolimnion is the coldest layer of a lake in summer, and the warmest layer during winter. Being at depth, it is isolated from surface wind-mixing during summer, and usually receives insufficient irradiance (light) for photosynthesis to occur. 🞂 ​In deep, temperate lakes, the bottom-most waters of the hypolimnion are typically close to 4°C throughout the year. The hypolimnion may be much warmer in lakes at warmer latitudes. 🞂 ​Lake overturn is a circulation which recharges oxygen and nutrients through the basin. In temperate lakes, the changing of the seasons help move water in the lake. Tropical lakes often stay stratified because warm water always stays on the top. In temperate lakes the winter months chill the surface water so that it gets colder than the water underneath, causing it to sink. This happens in the spring and fall 🞂 ​Amictic: never mix as they are permanently frozen. 🞂 ​Meromictic: mix only partially, the deeper layers never mix either because of high water density caused by dissolved substances or because the lake is protected from wind effects. 🞂 ​Holomictic: mix completely. 🞂 ​Oligomictic: do not mix every year as they are large and have higher heat storing capacity, the mixing depending on specific climatic conditions. 🞂 ​Monomictic: mix only once each year, either in winter or summer. 🞂 ​Dimictic: mix twice a year and are the most common lakes in temperate latitudes. 🞂 ​Polymictic: mixing frequently, they are the zone that mixes completely at least once a year 🞂 ​Chemocline- The intermediate layer, where there is a sudden change in density at the upper edge of bottom layer accumulating salts or dissolved organic matter. 🞂 ​Monimolimnion- the 🞂 ​Mixolimnion- 🞂 ​Meromixis can be: 🞂 ​Ectogenic when external events transport salt water into a freshwater lake or vice versa; 🞂 ​Crenogenic, when a saline spring at the bottom of the lake introduces in it water rich in salts 🞂 ​Biogenic, when salts from organic matter decomposition in sediments or from carbonates precipitation due to pH changes promoted by photosynthesis accumulate in the deeper layers. 🞂 ​Lakes are extremely variable in their physical, chemical and biological characteristics. 🞂 (level of light, temperature and water currents) 🞂 ​Chemical ( nutrients, major ions and contaminants) 🞂 ​Biological( biomass, population numbers and growth) 🞂 ​Physical 🞂 ​Light 🞂 ​Temperature 🞂 ​Water Currents 🞂 ​Solar radiation – fundamentally important Plankton production – photosynthesis � � (day) Respiration (night) � 🞂 �​Metabolism of the lake – controls the ecosystem 🞂 ​Ozone and oxygen – absorb ultraviolet rays 🞂 ​Vapor, Ozone and carbon dioxide – absorb infrared light 🞂 ​Light plays an important role in lake ecology and determines the potential rate of photosynthesis, which supplies dissolved oxygen and food in the water. 🞂 energy stored in photosynthetically formed organic matter is both synthesised within the lake or stream 🞂 ​Allochthonous - energy stored in photosynthetically formed organic matter within drainage basin and brought to the lake or stream in various forms 🞂 ​Autochthonous- 🞂 ​Light intensity at the lake surface varies seasonally and with cloud cover and decreases with depth down the water column. The deeper into the water column that light can penetrate, the deeper photosynthesis can occur. 🞂 ​Photosynthetic organisms include algae suspended in the water (phytoplankton), algae attached to surfaces (periphyton), and vascular aquatic plants (macrophytes). 🞂 ​Factors Influencing Light Penetration ◦ Latitude ◦ Season ◦ Angle of contact of light rays at water surface ◦ Time of the day ◦ Degree of cloudiness or clearness of the sky, presence of fog, smoke, dust or other atmospheric conditions. ◦ Dissolved ions – diminish light absorption. Traces of ammonia, proteins and nitrates in solution still reduce transparency of water to Ultraviolet light ◦ Suspended materials – composed of organic or inorganic materials. They screen out the light (ex. Phytoplankton, clay particles and abiotic materials) 🞂 ​Water is most dense at 4°C and becomes less dense at both higher and lower temperatures. Because of this densitytemperature relationship, many lakes in temperate climates tend to stratify, that is, they separate into distinct layers. 🞂 Stratification – the presence of different temperatures in a body of water 🞂 ​- Occurs in deep bodies of water 🞂 ​- Sometimes, it also occur in shallow ponds 🞂 ​Thermal 🞂 ​density differences 🞂 ​Turbidity – turbid water absorbs more heat in a warm sunny day 🞂 ​No water inflow 🞂 ​Cooling the surface through evaporation 🞂 ​Inflow of cold water rain 🞂 ​Strong wind action – cause water turbulence 🞂 ​use of mechanical aerators 🞂 ​Disappearance of heavy phytoplankton blooms The watershed, also called the drainage basin, is all of the land and water areas that drain toward a particular river or lake. 🞂 ​Thus, a watershed is defined in terms of the selected lake (or river). There can be subwater sheds within watersheds. 🞂 ​For example, a tributary to a lake has its own watershed, which is part of the larger total drainage area to the lake. 🞂 ​ - refers to physical factors (shape, size, structure, etc) that determine the lake basin. 🞂 ​Morphometry 🞂 ​Generally, lakes that are small in surface area and larger in depth exhibit higher water quality than those that are larger in surface area and shallow in depth. This is referred to as surface to volume ratio (S/V). 🞂 ​ Increasing quality decreases ratio of watershed to lake area- water ◦ Seepage lakeLake with small watersheds, maintained primarily by groundwater flow. ◦ Drainage lake- lake fed by inflowing streams or rivers are known as drainage lakes 🞂 ​ Land use – Urban areas tend to have higher flushing rate causing erosion 🞂 ​ Soil type 🞂 ​ Type and abundance of vegetation- Areas with native undisturbed vegetation are less prone to erosion than areas with disturbed vegetation like agricultural lands. 🞂 ​ Open and closed system- closed system is more stagnant than open system 🞂 ​Dissolved Oxygen 🞂 ​Carbon Dioxide 🞂 ​pH 🞂 ​Nitrogen 🞂 ​Phosphorous 🞂 ​ The chemical composition of a lake is a function ◦ Climate ◦ Hydrology ◦ Basin geology. THOSE THAT GO WHERE THEY CHOOSE Amphibia Larger Fish ns Turtles Zooplankton Insects THOSE THAT GO WHERE THE WATER TAKES THEM LIVING THINGS = PLANKTON DEAD MATERIAL = DETRITUS animals - zooplankton internal - produced within lake algae - phytoplankton external - washed in from watershed bacteria - bacterioplankton THOSE THAT LIVE ON THE LAKE BOTTOM BENTHOS = ANIMALS PLANTS BACTERIA & FUNGI aquatic insects higher plants sewage sludge macrophytes aufwuchs molluscs - clams, snails attached mixture of other algae algae, fungi invertebrates periphyton and bacteria worms, crayfish 🞂 ​Megaplankton. > 20 cm 🞂 ​Macroplankton. 2-20 cm 🞂 ​Mesoplankton. 0.2 – 20 mm 🞂 ​Microplankton. 20- 200 m 🞂 ​Nanoplankton. 2- 20  m 🞂 ​Picoplankton. 0.2- 2  m 🞂 ​Femtoplankton. 0.02- 0.2  m Organisms that spend their entire lives in the plankton. 🞂 ​Meroplankton. Organisms that spend but a part of their lives in the plankton 🞂 ​Holoplankton. 🞂 Small swimming organisms inhabiting the surface water film (10 cm) � Epineuston- aerial side � Hyponeuston- aquatic � side � 🞂 ​Neuston. � � 🞂 ​ The biological communities within lakes may be organized conceptually into food chains and food webs. 🞂 ​The broad base of primary producers supports overlying levels of herbivores (zooplankton), planktivores and much smaller numbers of carnivores (predators). 🞂 ​ These individual trophic levels may be idealized as a food chain, but in fact many organisms are omnivorous and not necessarily characterized by a particular level. 🞂 ​Consumers often shift levels throughout their life cycle. For example, a larval fish may initially eat fine particulate material that includes algae, bacteria and detritus. Then it may switch and graze on larger zooplankton and ultimately end up feeding on so called "forage fish" or even young game fish (i.e., top predators) when it reaches 🞂 ​Three main factors regulate the trophic state of a lake 🞂 ​Rate of nutrient supply 🞂 ​Climate 🞂 ​Shape of lake basin (morphometry) 🞂 ​Rate of nutrient supply 🞂 ​Bedrock geology of the watershed 🞂 ​Soils 🞂 ​Vegetation 🞂 ​Human landuses and management 🞂 ​Climate 🞂 ​Amount of sunlight 🞂 ​Temperature 🞂 ​Hydrology (precipitation + lake basin turnover time) 🞂 ​Shape of lake basin (morphometry) 🞂 ​Depth (maximum and mean) 🞂 ​Volume and surface area 🞂 ​Watershed to lake surface area ratio (Aw : Ao) 🞂 is the process by which a body of water becomes enriched in dissolved nutrients (such as phosphates) that stimulate the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen. 🞂 ​Eutrophication 🞂 🞂 🞂 🞂 ​Noxious algae (scums, blue-greens, taste and odor, visual) 🞂 ​Excessive macrophyte growth (loss of open water) 🞂 ​Loss of clarity (secchi depth goes down) 🞂 ​Possible loss of macrophytes (via light limitation by algae and periphyton) 🞂 ​Low dissolved oxygen (loss of habitat for fish and fish food) 🞂 ​Excessive organic matter production (smothering eggs and bugs) 🞂 ​Blue-green algae inedible by some zooplankton (reduced food chain efficiency) 🞂 ​"Toxic" gases (ammonia, H2S) in bottom water (more loss of fish habitat) 🞂 ​Possible toxins from some species of bluegreen algae 🞂 ​Chemical treatment by lakeshore homeowners or managers may 🞂 ​Drinking water degradation from treatment disinfection byproducts 🞂 ​Carcinogens, such as chloroform (from increased organic matter reacting with disinfectants like chlorine) 🞂 ​ Roots are anchored in the bottom bud. Ex: Spike rushes and small sedges 🞂 ​ Narrow, tubular, linear leaves and have broad leaves. Ex. Bulrushes, reeds, and cattails 🞂 ​ Poorly developed root system but highly developed aerating system. Ex. Pond lily (Nuphar spp.) and Pond weed (Potamegaton) 🞂 ​ Lacks cuticles. These plants absorb nutrients and gases directly from the water through thin and finely dissected or ribbon like leaves. Ex. Certain pond weed species (Chara muskgrass) 🞂 ​ Have compressed bodies that permit them to move with ease through the masses of aquatic plants. Fishes lack strong lateral muscles characteristics of fish living in swift water such as sunfish. 🞂 ​ Carry a bubble of air with them when they go under water in search of prey. Diving insects such as water 🞂 ​Spike rushes and small sedges Adaptation: Roots are anchored in the bottom bud. 🞂 ​Bulrushes, reeds, and cattails Adaptation: Narrow, tubular, linear leaves and have broad leaves 🞂 ​Pond lily (Nuphar spp.) and Pond weed (Potamegaton) Adaptation: Poorly developed root system but highly developed aerating system 🞭 Certain pond weed species (Chara muskgrass) Adaptation: Lacks cuticles. These plants absorb nutrients and gases directly from the water through thin and finely dissected or ribbon 🞭 Fishes Lack Strong Lateral Muscles Characteristics Of Fish Living In Swift Water Such As Sunfish. Adaptation: Have Compressed Bodies That Permit Them To Move With Ease Through The Masses Of Acquatic Plants. 🞂 ​Diving Insects Such As Water Boatman And Diving Beetles Adaptation: Carry A Bubble Of Air With Them When They Go Under Water In Search Of Prey. 🞂 ​Urbanization. Reclamation of some portions of the lake. 🞂 ​Overfishing. Increased fishing pressure. 🞂 ​Increased sewage effluents 🞂 ​ Introduction of exotic species accidentally or on purpose 🞂 ​ Human activities like road construction, logging, mining and agriculture affects the lake physical, chemical and biological aspects. 🞂 🞂 1 . Plankton 2.Submergent 3.Floating 4. emergent 5.Benthos 6.Nekton 7.Eutrophication 8.Rate of nutrient supply 9. Climate 10. Shape of basin (morphometry)