ECOSYSTEM TYPES

ECOSYSTEM TYPES

What process helps in restoring forests?

Afforestation establishes tree cover on land that has long been non-forested or substantially degraded, and it can help restore forest functions such as carbon storage, erosion control, water regulation, habitat provision, and microclimate moderation. Closely related reforestation restores trees to recently cleared forest land; the two terms are sometimes distinguished in forestry statistics. Successful ecological restoration requires more than planting any trees. Native species, appropriate genetic sources, soil condition, hydrology, fire regime, landscape connectivity, and the needs of local

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

Which ecosystem is least productive?

Deserts generally have the lowest primary productivity among the terrestrial ecosystems listed because water availability sharply limits photosynthesis, leaf area, and the length of active growth. Rainfall is sparse and unpredictable, and evaporation may exceed precipitation. Plants often remain widely spaced and invest resources in water storage, conservative metabolism, or extensive roots rather than continuous rapid growth. Productivity can surge briefly after rain, but annual net primary production remains low. Forests maintain much larger leaf area and biomass where temperature and water

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

What does eutrophication cause?

Eutrophication is enrichment of water with nutrients, especially phosphorus in many fresh waters and nitrogen in many coastal systems. The added nutrients remove a growth limitation on phytoplankton or cyanobacteria, allowing rapid population increase that appears as an algal bloom. Dense blooms reduce water clarity and shade submerged vegetation. When algal cells die, bacteria decompose the organic matter and consume dissolved oxygen; stratified bottom waters may then become hypoxic or anoxic. Fish kills, loss of oxygen-sensitive species, toxin-producing cyanobacteria, unpleasant odours, and

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

Where is photosynthetic activity highest in lakes?

The littoral zone is the shallow lake margin where sunlight reaches the bottom, allowing rooted macrophytes, attached algae, and phytoplankton to photosynthesize. Plants occupy both the sediment and water column, creating a large photosynthetic surface and structurally complex habitat. Nutrients arrive from shoreline soils, runoff, decomposing vegetation, and sediment recycling, while wave action and animal activity can return them to the water. Consequently, areal primary production is often especially high in the littoral region. The profundal zone lies below effective light penetration and

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

Which grassland has scattered trees?

A savanna is a tropical or subtropical grassland in which a continuous or nearly continuous herbaceous layer coexists with scattered trees and shrubs. Seasonal rainfall supplies enough water for some woody plants but not enough, or not consistently enough, to maintain a closed forest canopy. Fire and grazing are equally important: grasses can regrow from protected basal tissues, whereas frequent burning and herbivory limit many tree seedlings. Adult trees often have deep roots, thick bark, small leaves, or drought-deciduous foliage. The balance among rainfall, fire, soil, herbivores, and human

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

What organisms float on water surface?

Neuston are organisms that live at or immediately adjacent to the air-water interface. Some rest on top of the surface film, termed epineuston, while others occupy its underside, termed hyponeuston. Examples include water striders, floating microbial communities, certain algae, fish eggs, larvae, and small invertebrates. Surface tension creates a specialized habitat, and strong gradients in light, temperature, oxygen, and chemicals distinguish it from deeper water. Wind can aggregate neuston into slicks, while ultraviolet radiation and pollutants concentrated at the surface impose stress. Bent

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

What defines a fen wetland?

A fen is a peat-forming wetland supplied by groundwater or mineral-rich surface water in addition to precipitation. Water moving through soil and rock carries dissolved calcium, magnesium, bicarbonate, and other ions, making most fens less acidic and more nutrient-rich than rain-fed bogs. Some are neutral or alkaline, especially in limestone regions, although mildly acidic fens also occur; groundwater influence is more fundamental than a universally high pH. Sedges, grasses, brown mosses, and specialized flowering plants commonly dominate, and peat accumulates because saturation restricts oxyg

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

What type of forest grows after disturbance?

A secondary forest develops after a disturbance removes or damages an earlier forest but leaves a biological legacy, especially soil. Fire, storms, logging, shifting cultivation, or abandoned farmland can initiate this recovery. Seeds in the soil, surviving roots and stumps, nearby seed sources, microbes, nutrients, and existing soil structure allow vegetation to return faster than during primary succession on newly exposed rock. Early colonists are often fast-growing, light-demanding herbs, shrubs, and trees. As their canopy develops, shade, litter, soil moisture, and competition change, allo

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

Which water body is brackish and tidal?

An estuary is a partly enclosed coastal water body where river water mixes with seawater and tidal action influences water level and circulation. Mixing produces brackish water, whose salinity lies between fresh and fully marine conditions and often varies over each tide, season, and position along the estuary. Density differences can create a salt wedge or partial stratification, while tidal currents transport sediments, oxygen, nutrients, plankton, and organisms. Estuaries support salt marshes, mangroves, mudflats, seagrass beds, nursery grounds, and productive detrital food webs. A river is

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

What describes the neritic zone?

The neritic zone is the shallow marine water extending from the low-tide margin to the edge of the continental shelf. Its exact offshore width varies because continental shelves may be narrow or hundreds of kilometres broad, but depth commonly remains below about 200 metres. Sunlight can reach much or all of this water column, while rivers, coastal runoff, sediment resuspension, and upwelling often supply nutrients. These conditions support phytoplankton, seaweeds, seagrasses, benthic invertebrates, fishes, and many commercial fisheries. The neritic zone is not simply the shoreline: the intert

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

Which oceanic zone has highest biodiversity?

The epipelagic zone, extending from the surface to roughly 200 metres, generally supports the greatest biodiversity among the listed open-ocean depth zones because it receives enough light for photosynthesis. Phytoplankton convert solar energy and inorganic nutrients into organic matter, forming the energetic base for zooplankton, fishes, turtles, marine mammals, and numerous predators. Warm temperatures, relatively high oxygen, wave-driven mixing, and habitat variation near fronts and floating structures further expand ecological opportunities. Much of the ocean’s primary production occurs he

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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ECOSYSTEM TYPES

Which ecosystem receives

Deserts are commonly defined by chronic water limitation, and many receive less than about 250 millimetres of precipitation per year. Low rainfall, often combined with high evaporation, prevents continuous tree cover and limits primary productivity. Desert organisms show water-conserving adaptations: plants may use CAM photosynthesis, reduced leaves, succulent tissues, deep or widespread roots, and rapid life cycles after rain; animals may be nocturnal, burrowing, or produce concentrated urine. Not all deserts are hot. Polar and high-altitude deserts can be cold, demonstrating that aridity rat

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3

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