Name: microbes in streams, lakes, and rivers
Uploaded: 2026-03-12T13:57:36.000Z
Duration: 1 min 24 s
Channel: JoVE

K12 Standards

Alabama Course of Study Science

9-12

Environmental Science

Unity and Diversity

9-12.EVS.2.3.b

Freshwater Microbial Ecology

Tatlı su mikrobiyal ekolojisi, organik karbon, besinler, oksijen ve ışığın varlığıyla şekillenir.Yüzeye yakın yerlerde, fitoplankton güneş ışığını kullanarak karbondioksiti organik karbona dönüştürür.Sığ sularda diatomlar organik karbon üretimine katkıda bulunurken, heterotrofik mikroplar bu organik karbonu parçalayarak karbondioksit salgılar ve besinleri suya geri döndürür.Su altındaki yüzeylerdeki biyofilmler, bakteriler, mantarlar ve protistlerin birlikte çalışarak suyu parçalayıp karbondioksit salındığı organik maddeyi hapseder.Bentik bölgeler genellikle yaprak döküntülerinden ve heterotrofik mikroplar tarafından bozunan su altında kalmış organik maddeden karbon alır.Bu mikroplar, çözünmüş organik karbonu suya geri salarak yakındaki mikrobiyal toplulukları destekler.Kentsel ve tarımsal akış, organik atıkları tatlı suya sokabilir ve bu da ötrofikasyona yol açar.Bu, yüzeyde siyanobakteriyel patlamaları ve heterotrofik mikropların fazla biyokütleyi parçalamasıyla oksijen azalmasını teşvik eder ve mikrobiyal topluluğun genel yapısını etkiler.

tatlı su mikrobiyal ekolojisi

Dereler, nehirler ve göller gibi tatlı su sistemleri, mikrobiyal topluluklarını etkileyen belirgin fiziksel ve biyolojik özellikler sergiler. Bu ortamlar genel olarak lotik sistemler—akarsu olan dereler ve çoğu nehir gibi—ve göller, göletler ve bataklıklar gibi durgun veya yavaş akan suları içeren lentik sistemler olarak kategorize edilir.Lentik sistemlerde fitoplankton birincil üretimi yönlendirir ve otokton organik karbon üretir. Buna karşılık, lotik sistemler türbülans, düşük ışık ve hızlı karışım yaşar; bu da plankton büyümesini sınırlar. Bu akan sular ise çevredeki bitki örtüsü ve insan faaliyetlerinden gelen çözünmüş ve partikül allokton karbon girdilerine dayanır ve mikrobial kolonileşmeyi destekler.Dereler ve nehirler genellikle hem fotosentetik organizmalar hem de heterotroflardan oluşan biyofilmlerle canlı bentik mikrobiyal toplulukları destekler. Bu biyofilmler, besin geri dönüşümü ve organik madde ayrışmasında kritik bir rol oynar. Ancak, kentsel akış veya tarımsal faaliyetlerden kaynaklanan bozulmalar bu dengeyi bozabilir ve oksijen seviyelerinin azalmasına, yani oksijen çökmesine ve potansiyel anoksiye yol açabilir. Atık su boşaltımı gibi nokta kaynak kirliliği ve çiftliklerden gelen akış gibi nokta olmayan kaynak kirliliği mikrobiyal dinamikleri değiştirebilir ve su kalitesini düşürebilir.Göller, lentik doğaları nedeniyle önemli ölçüde farklılık gösterir. Mikrobiyal yapıları derinlik, besin bulunabilirliği ve termal tabakalaşma ile etkilenir. Sığ göller su sütunu boyunca bentik ototrofları destekleyebilirken, derin göller yaz aylarında belirgin termal tabakalar geliştirir. Üst epilimnion oksijen açısından zengin ve verimlidir; derin hipolimnion ise sınırlı karışım ve solunum nedeniyle oksijen difüzyonu daha hızlı olduğu için genellikle anoksik hale gelir. Sonbahar ve ilkbaharda mevsimsel değişimler besinleri yeniden dağıtabilir ve geçici çiçeklere yol açar.Tropikal göller, yazın ılıman göllere benzer olsalar da, yıl boyunca sıcaklık ve yağış kaynaklı dinamikler yaşar. Bu, özellikle azot fiksörlüğü sağlayan siyanobakteriler tarafından sürekli verimlilik ve sık çiçeklenmeleri teşvik eder. Göller ayrıca besin içeriği açısından da değişiklik gösterir; yıl boyunca oksijenli kalan besin açısından yoksun, oligotrofik sistemlerden, büyük siyanobakteriyel popülasyonları destekleyen besin açısından zengin ötrofik göllere kadar değişir. Bu mikroplar alkali, sıcak sularda gelişir ve ökaryot algleri alt edebilir, bazen toksin üretebilir ve su kalitesini değiştirebilir.

Tatlı Su Mikrobiyal Ekolojisi

Freshwater systems such as streams, rivers, and lakes exhibit distinct physical and biological characteristics that influence their microbial communities. ...

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Education

JoVE Core

Microbiology

Mikrobiyoloji

Unit

Birim

Microbial Ecology

Mikrobiyal Ekoloji

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

microbes in streams, lakes, and rivers

Freshwater microbes live in streams, rivers, lakes, ponds, and marshes, but their communities change with water movement, light, depth, and nutrients. These systems are often grouped into lotic waters, which flow, and lentic waters, which are still or slow-moving. The physical setting shapes where microbes grow and how they get energy.

In lentic systems, phytoplankton are the main producers. They make autochthonous organic carbon, which means carbon made within the water body. In lotic systems, rapid mixing, low light, and turbulence limit plankton growth. These flowing waters depend more on allochthonous carbon, which is material that comes from outside the water, such as vegetation and human activity.

Streams and rivers often have active benthic microbial communities on the bottom. Their biofilms include photosynthetic organisms and heterotrophs, which must obtain energy from organic matter. These biofilms help recycle nutrients and break down organic matter. Urban runoff or agricultural activity can disturb this balance and lower oxygen levels, a pattern called oxygen sag, which can lead to anoxia, or very low oxygen.

Pollution also changes freshwater microbes. Point source pollution, such as wastewater discharge, and nonpoint source pollution, such as farm runoff, can shift microbial communities and reduce water quality. Lakes show another set of patterns because depth and thermal stratification, or layering by temperature, strongly affect them. Shallow lakes may support benthic autotrophs through much of the water column, while deeper lakes form separate layers in summer.

In deep lakes, the upper epilimnion is oxygen-rich and productive. The lower hypolimnion often becomes anoxic because mixing is limited and respiration uses oxygen faster than it can diffuse downward. Seasonal overturn in autumn and spring can move nutrients through the water and trigger short-lived blooms. Tropical lakes also support frequent blooms, but they stay warm year-round and respond strongly to rainfall, especially when nitrogen-fixing cyanobacteria grow.

Lakes also vary in nutrient level. Oligotrophic lakes are nutrient-poor and usually stay oxygenated throughout the year. Eutrophic lakes are nutrient-rich and can support large cyanobacterial populations. These microbes do well in warm, alkaline water and may outcompete eukaryotic algae. Some can also produce toxins and change water quality.

Microbes in Streams, Lakes, and Rivers

introduction to microbial ecology

Microbial Communities in Soil and Extremes

Microbial ecology looks at how microorganisms live, interact, and adapt in different ecosystems. It also shows how these tiny organisms help shape nutrient cycling, energy flow, and environmental balance. An ecosystem includes living parts and non-living parts, and microbes respond to both. Microorganisms can form populations, which are groups of the same species living together at the same time. When populations from different species live and interact in the same place, they form a microbial...

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Microbial Niches in Ecosystems

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methods to assess microbial populations

Measuring Microbes in Samples

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methods to assess microbial communities

Measuring Microbial Diversity and Activity

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microbial interactions: cooperation

Microbial Cooperation in Soil and Hosts

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microbial interactions: predation

How Microbes Hunt and Defend

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microbial interactions: competition

Microbial Competition and Niche Partitioning

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microbial interactions: parasitism

Microbial Parasites and Host Dependence

Microbial parasites depend on a host for nutrients and shelter, and this dependence often harms the host. In parasitism, only the parasite benefits. This is different from mutualism, where both organisms gain from the relationship. Microbial parasites are classified by where they live in or on the host. Ectoparasites stay on the host’s surface, such as the skin or outer tissues, and take in nutrients from outside. Endoparasites live inside the host’s body and invade tissues or organs.

microbe-plant interactions

How Plant Microbes Affect Growth

Plant microbes can help, harm, or simply live alongside their hosts. These microbe-plant interactions shape plant growth, health, and ecosystem function. The plant microbiome includes bacteria, fungi, archaea, protists, and viruses, and these organisms may live on the plant surface, inside plant tissues, or in symbiosis throughout the plant. Some of the most important beneficial partnerships involve mycorrhizal fungi. These fungi form close connections with roots and are grouped as arbuscular...

microbes and the carbon cycle

How Microbes Move Carbon Through Earth

Microbes move carbon through Earth’s major reservoirs and help drive the carbon cycle. Carbon shifts among the biosphere, lithosphere, atmosphere, and hydrosphere, where it supports life and helps regulate climate. It commonly cycles as carbon dioxide (CO2), the oxidized form of carbon, but methane (CH4) and organic compounds also matter. Photosynthetic microbes take in atmospheric CO2 and turn it into organic carbon. Cyanobacteria are especially important because they carry out oxygenic...

microbes and methanogenesis

How Microbes Produce Methane

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microbes and the nitrogen cycle

Microbial Steps in the Nitrogen Cycle

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microbes and other elemental cycles

Microbes Driving Iron and Manganese Cycles

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marine microbial ecology

Microbial Life in the Ocean

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deep sea microbial ecology

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Deep sea microbes live in one of Earth’s harshest environments. The deep ocean is far below the sunlit photic zone, which usually reaches the upper 100 to 200 meters of open water. Below that layer, the bathypelagic and abyssal zones stretch from about 1,000 to 6,000 meters, and hadal trenches go even deeper. This region is dark, cold, and highly pressurized. Temperatures are usually around 2 to 3°C, although hydrothermal vents can be slightly warmer. Pressure rises by about 1 atmosphere for...

freshwater microbial ecology

Freshwater microbes live in streams, rivers, lakes, ponds, and marshes, but their communities change with water movement, light, depth, and nutrients. These systems are often grouped into lotic waters, which flow, and lentic waters, which are still or slow-moving. The physical setting shapes where microbes grow and how they get energy. In lentic systems, phytoplankton are the main producers. They make autochthonous organic carbon, which means carbon made within the water body. In lotic...

soil microbial ecology

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key terms and concepts

Explore how water flow, depth, nutrients, and pollution shape freshwater microbes in streams, rivers, lakes, and cyanobacteria blooms.

Microbes in Streams, Lakes, and Rivers | JoVE K12

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Microbes in Streams, Lakes, and Rivers

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