Plants and the Littoral Zone

Littoral Zone

The zone that sustains diverse aquatic plants and reflects varied ecological interactions across different water bodies, influencing macrophyte growth and community structure.

Emergent Zone (Littoral)

A zone within the littoral region where emergent macrophytes primarily grow.

Floating-Leaved Zone (Littoral)

A zone within the littoral region characterized by plants with floating leaves.

Submergent Zone (Littoral)

A zone within the littoral region characterized by submerged aquatic plants.

Deep Water or Open Zone (Littoral)

A zone beyond the immediate shoreline macrophytes, leading into deeper water.

Emergent Macrophytes

Aquatic plants rooted in the substrate with leaves fully exposed to air, typically rhizomatous, possessing aerenchyma or lacunae. They uptake nutrients from sediment and inorganic carbon from the air.

Rhizomatous

Plants that spread via underground stems.

Aerenchyma or Lacunae

Air-filled spaces within plant stems and leaves that facilitate gas exchange.

Typha

Commonly known as cattail, a monocot related to grasses and characteristic of wetland communities.

Glyceria

Common name: mannagrass, an aquatic grass with rough leaves.

Phragmites

Common name: common reed, an aggressively growing grass in aquatic and semi-aquatic environments.

Zizania

Common name: wild rice, related to true rice (Oryza).

Eleocharis

Common name: spikerush or spikesedge, a grass-like plant in the sedge family with spike-like stems without leaves.

Scirpus

Common name: bulrushes, a plant in the sedge family with rhizomatous, hollow stems and leaves associated with subapical inflorescence.

Carex

A dominant genus of sedges (over 1500 species), characterized by grass-like plants with triangular stem cross-sections.

Juncus

Common name: rush, forms tufts of spike-like stems from a basal rosette of leaves, superficially resembling Eleocharis.

Polygonum

Common names: smartweed or knotweed, characterized by swollen nodes, with native species often found at margins of lakes, ponds, and rivers.

Japanese Knotweed

An invasive Polygonum species found near wet areas but rarely in water.

Equisetum

Common name: horsetail, with E. fluviatile (river horsetail) being a species common in water and related to ferns.

Floating-Leaved Rooted Macrophytes

Aquatic plants that are generally rhizomatous, with floating leaves possessing a cuticle on the upper surface and a long petiole. They uptake nutrients from sediments and inorganic carbon from both water and air.

Petiole

The leaf stalk, particularly long in floating-leaved rooted macrophytes.

Nuphar

Common names: spatterdock or cow lily, a rhizomatous plant with large floating leaves and submerged stems and roots, common in the northern hemisphere.

Nymphaea

Common name: water lily, similar to Nuphar but with large, showy flowers popular in water gardens.

Brasenia

Common name: watershield, a smaller rhizomatous plant than Nuphar whose stems emerge from the substrate.

Nelumbo

Common name: lotus, resembles Nymphaea with some emergent leaves, with one species native to North America.

Potamogeton

Common name: pondweed, a rooted plant with elongate stems and floating leaves.

Unrooted Floating-Leaved Macrophytes

Aquatic plants, many with gas-filled floats or tissue, some with entirely aerial leaves, possessing hanging root systems or modified tissues. They uptake nutrients entirely from water and inorganic carbon from the air, and have highly reduced stems.

Lemna

Common name: duckweed, a common floating plant found throughout the northern hemisphere.

Wolffia

Common name: water meal, recognized as the world’s smallest flowering plant, often found alongside Lemna.

Eichhornia

Common name: water hyacinth, a large free-floating plant from South America that is a noxious weed in southern US waterways.

Pistia

Common name: water lettuce, originally from Egypt and now widespread in tropical and subtropical waterways, serving as a pest in various US waterways.

Free-Floating Unrooted Macrophytes

Aquatic plants that are almost entirely submerged but may float at the surface, typically with highly dissected leaves. Fragmentation is a major form of reproduction and dispersal, and they rarely have roots, taking up nutrients from water.

Utricularia

Common name: bladderwort, an aquatic carnivorous plant with over 250 global species, some of which are considered pests.

Ceratophyllum

Common names: hornwort or coontail, a global plant often found in hard water ponds and lakes.

Submerged Rooted Aquatic Plants

Aquatic plants with typically highly dissected leaves that uptake nutrients from both water and the substrate.

Myriophyllum

Common name: water milfoil, native to Eurasia and a pest in many still water bodies.

Elodea

Common name: waterweed, a submerged plant native to North America that can root in sluggish streams, abundant in nutrient-rich lakes and ponds, and used as an aquarium plant.

Vallisneria

Common names: water celery or tape grass, a rooted plant with broad leaves frequently found in local creeks.

Isoetes

Common name: quillwort, a fern ally with corm-like bases to leaves, indicative of acid-sensitive waters, sometimes emergent.

Chara

Common names: muskgrass or skunkweed, a non-vascular plant often found in hard water ponds, with many species emitting a fetid odor.

Nitella

Common names: stoneworts or brittleworts, related to Chara, may occur in soft water ponds, and are soft to touch due to no calcium carbonate deposition.

Zonation in Ozera Nero

The plant succession from the shore to the lake center in Ozera Nero, including Salix, Phragmites, Typha, Scirpus, Equisetum, Potamogeton, Nuphar, Lemna, and Ceratophyllum.

Macrophytes in Sam Rayburn Reservoir

Marginal macrophytes that form tight concentric bands in Sam Rayburn Reservoir, consisting of Nitella, Potamogeton, and Elodea.

Macrophytes in Main Stem of Susquehanna River

Beds of macrophytes found in backwater areas and clear waters of the West Branch, including Vallisneria, Potamogeton, Polygonum, Elodea, and Glyceria.

Impacts of Macrophyte Dominance

Effects of dominance include high primary production, decreased water turbulence, more efficient nutrient uptake and sequestration compared to algae, increased water clarity, and high organic load.

Heterophylly

The phenomenon where many aquatic plant species exhibit differences in leaf shape when submerged or emerged.

Asexual Reproduction (Aquatic Plants)

Methods such as winter buds and agamospermy (e.g., Potamogeton).

Agamospermy

Asexual reproduction without fertilization.

Vegetative Reproduction (Aquatic Plants)

A common asexual reproductive method in aquatic plants (e.g., Myriophyllum).

Sexual Reproduction (Aquatic Plants)

Methods including insect pollination (e.g., Nuphar), wind pollination (e.g., Typha), and water pollination (e.g., Potamogeton and Elodea).

Gaseous Movement (Throughflow)

Convective gas flow within aquatic plants due to thermal transpiration and humidity, which is diffusion-dependent.

Carbon Uptake Adaptations (Aquatic Plants)

Unique adaptations include no cuticle in submerged leaves, chloroplasts located in the epidermis of leaves, ability to decarboxylate bicarbonate, and carbon recirculation via aerenchyma/lacunae.

Decarboxylate Bicarbonate

The process by which some aquatic plants can convert bicarbonate (HCO_{3}) into carbon dioxide (CO_{2}) for photosynthesis.

CAM Metabolism

A specialized metabolic pathway found in specific aquatic and desert plants that allows CO_{2} uptake at night when inorganic carbon levels are highest in water.

Photosynthetic Efficiency (Aquatic Macrophytes)

The efficiency of photosynthesis in aquatic macrophytes, illustrated in relation to light and oxygen dynamics.

Growth or Metabolism Patterns (Aquatic Macrophytes)

Typical growth and metabolic patterns described through seasonal fluctuations in biomass, including annual patterns of germination, self-shading effects, and metrics on biomass and productivity.

Biomass Relationships (Aquatic Plants)

Illustrated graphical relationships between aquatic plant biomass and essential nutrient concentrations, showing effects of phosphate and nitrate enrichment (e.g., on Scirpus subterminalis).

Seasonal Variations (Aquatic Macrophytes)

Seasonal fluctuations in shoot density, reproductive cycles, and maximum biomass observed in aquatic macrophytes (e.g., Juncus effusus).

Relationship Between pH and Alkalinity (Aquatic Plants)

Notable pH changes linked to submerged macrophyte communities, indicating ecological impacts assessed in areas like Sangwin Pond.

Littoral Zones in Rivers

Development of land-water interfaces, macrophyte communities, and nutrient acquisition, with dominant types including emergent and floating-submerged macrophytes.

Littoral Zones in Reservoirs

Characterized by predominantly rooted emergent plants, with nutrient acquisition primarily through roots.

Littoral Zones in Lakes

Well-developed interfaces with diverse macrophyte communities thriving under various nutrient and light conditions.