How does cyanobacteria grow

Blue-green algae blooms are a worldwide problem in lakes heavily polluted with nutrients. Current research shows that if climate change causes further warming of lakes and estuaries, blooms will become more intense and more toxic. It will be easier to control blooms by curtailing nutrient inputs now than it will be in a warmer future. Lake Okeechobee and the Caloosahatchee and St.

Lucie Estuaries experienced intense blooms in both and that lasted throughout the summer into the fall. There is currently a bloom in Lake Okeechobee, but it is not as large or intense as the bloom. During an algae bloom, millions of phytoplankton cells lurk in every milliliter of water, and sometimes they produce toxins.

Some of these toxins can cause fish kills, respiratory distress and skin irritation. Blue-green algae blooms have been known to kill household pets, such as dogs and farm animals like cattle. Prolonged or high-level exposure to the blooms can also lead to liver disease and neurological problems.

Just the presence of a dense algae bloom can harm other aquatic life as well. For example, dense blooms can prevent light from reaching the aquatic plants growing on the bottom of estuaries and lakes, thereby suppressing their growth.

In some Midwestern states and in California, blooms are appearing in drinking water reservoirs, limiting the drinking water supply. When blue-green algae blooms spread to areas where people recreate or plan vacations, the sight and smell of the blooms can lead to canceled trips, which can impact local economies and businesses, particularly those related to fishing and tourism. His team has developed a web page showing satellite imagery of red tide blooms that will go live either in September, or at the onset of the next bloom.

Because there could be a lot of monitoring but it may not be addressing what needs to be done. According to Stumpf, scientists could better forecast future blooms by having access to:. Stumpf said he and his team are now processing satellite imagery from blooms in Florida since so that they can have a better idea of the environmental triggers that cause these blooms for more accurate forecasts.

He added that if the U. Army Corps of Engineers has access to more accurate forecasts, they may be able to refrain from releasing water from lake Okeechobee at a time when there is a high risk for a bloom developing. Intense algae blooms reflect decades of human intervention on the land — adding fertilizer, growing crops, raising cows and cattle, fertilizing lawns and installing septic tanks — around these once-pristine water bodies. In , Lake Okeechobee was at the center of a large inter-connected Everglades wetland.

Water flowed into the lake from the northeast and exited to the west, south, and southeast, either through meandering creeks or as a broad sheet flow. The swamp forest of pond apple trees and much of the sawgrass plains at the southern end have now been drained and converted to agriculture.

Skip to main content. Last Updated:. July Download PDF:. What are cyanobacteria blooms? What do cyanobacteria blooms look like and how long will they last? Are cyanobacteria harmful? How can I be exposed to cyanobacteria? What are the symptoms of exposure to cyanobacteria? Rinsing is recommended even without symptoms. How are pets and livestock exposed to cyanobacteria? How can I prevent illness from cyanobacteria? To prevent illness from cyanobacteria: Follow advice from your local government, health authority and ministries on what water is safe to drink and where it is safe to swim Never drink untreated water from lakes, ponds or wetlands.

Boiling water does not remove cyanobacterial toxins from the water and can even increase the concentration of toxins Never mix infant formula with water that you suspect contains cyanobacteria Follow swimming advisories related to cyanobacteria blooms or toxins Never wade, swim or bathe in water with visible blooms Never cook, wash dishes or do laundry in water contaminated with blooms Wear rubber gloves when washing a pet exposed to cyanobacteria.

They grow in any type of water fresh, brackish, or marine and are photosynthetic: They use sunlight to create food and survive.

Normally microscopic, cyanobacteria can become clearly visible in warm, nutrient-rich environments, which allow them to grow quickly and "bloom" in lakes and other bodies of water. These bacteria are commonly known as "blue-green algae" because of their color, texture, and aquatic location, but they're not plants like true algae. Blooms of cyanobacteria — when the population of cyanobacteria explodes — typically occur in still or slow-moving water, such as lakes, ponds, and weak streams, when the water is warm, gets plenty of sunlight, and is rich in nutrients like phosphorous and nitrogen.

In the United States, these blooms occur most often in summer and early fall, although they can occur any time of year, according to the Centers for Disease Control and Prevention CDC. Because most cyanobacteria species float in water, blooms often appear as foam, scum, or mats on the water's surface, and can cause clear water to become cloudy. A young man accidentally became immersed in an intense bloom of Microcystis spp. The patient was hospitalized in intensive care and diagnosed with an atypical pneumonia.

Complete recovery took 20 days. It is not known whether there was an eventual chronic intoxication after the acute poisoning. This episode coincided with the appearance of dermal and respiratory problems in the population [ 14 ]. The duration of cyanobacterial blooms in temperate zones can last 2—4 months during the summer period, whereas in tropical and subtropical regions of Australia, China, and Brazil, they can sometimes persist all year round [ 15 ].

The major factors that influence the growth of cyanobacteria are light, temperature, and the nutrients composition of the suspending medium. High water temperatures have been known to lead to cyanobacterial bloom development in temperate [ 16 , 17 , 18 ] and semiarid regions [ 19 ]. Increasing air and water temperatures as a result of climate change are likely to promote a faster algal growth rate [ 20 , 21 ]. The absolute and relative concentrations of these nutrients affect the growth rate, abundance, and composition of phytoplankton in lake water [ 22 ] as commonly measured in terms of their trophic state, defined as the total weight of biomass in a given water body at the time of measurement [ 23 ].

Many studies show that phosphorus is the limiting nutrient in freshwater bodies [ 24 , 25 ], and other studies show the relationship between cyanobacterial abundance and phosphorus concentrations in lakes [ 26 , 27 ]. The trophic state of a lake generally increases with increases in total nitrogen TN and total phosphorus TP concentrations. Resolving lake or river eutrophication problems calls for a better understanding of the water and air temperature-dependence of algal blooms.

A high P concentration is considered to be the main cause of Microcystis blooms in the Nakdong River of Korea [ 28 , 29 ].

Schindler [ 30 , 31 ] report that N is unlikely to be the limiting factor for blooms because of the presence of N 2 -fixing cyanobacterium in water bodies.

Provided factors such as illumination and nutrients remain saturating, and the photosynthetic and specific maximal growth rate responses of different algal species to temperature can be compared [ 34 ]. Physiological properties within a single species, including photosynthetic response, can change according to the growth conditions [ 37 ].

Photoperiodicity- and light intensity-dependent changes in photosynthetic parameters and different pigments such as chlorophyll a and phycocyanin are to be expected. The general consensus is that the optimum growth temperature for cyanobacteria is higher than that for most algae.

Crettaz Minaglia [ 39 ] reported the optimum growth temperature for native M. These data suggest that the native strain of M. This trend would be further facilitated by cyanobacterial buoyancy, which aids their proliferation in increasingly stratified conditions because decreasing water viscosity at higher temperatures results in higher flotation velocities of buoyant cyanobacteria [ 19 , 42 ].

Many authors describe an inverse relationship between temperature and microcystin production. Crettaz Minaglia [ 39 ] found that the production of MC-LR decreased with increasing temperature, coinciding with the findings of [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. In an interesting paper, Mowe et al. However, depending on the species, the toxin cell ratio may increase under moderate warming scenarios.

Further studies on the temperature dependency of the different physiological processes affecting growth e. An evaluation of microbiological cyanobacterial processes calls for kinetics studies examining the rates of production of cells and their metabolites and the effects of various factors on these rates.

One of the basic tools in microbiology is growth kinetics, defined as the relationship between a specific growth rate and parameters such as temperature, pH, light intensity, short wavelength radiations, pH, and nutrients.

A convenient way to evaluate laboratory-based bacteria growth systems under different abiotic factors is to examine the parameters characterizing the three phases of bacterial growth: the lag phase, the exponential phase, and the stationary phase.

During the lag phase, which can last from 1 hour up to several days, there is very little change in the number of bacteria cells because while they are adapting to the growth conditions, they are still immature and unable to reproduce. This is the period when the synthesis of RNA, enzymes, and other molecules occurs. The exponential phase is characterized by cell doubling. The number of new bacteria appearing per unit time is proportional to the present population.

With no limitations in place, doubling continues at a constant rate, leading to a doubling of the number of cells and the rate of population increase with each consecutive time period.

Plotting the logarithm of cell number against time produces a straight line, the slope of which indicates the specific growth rate of the organism, which is a measure of the number of divisions per cell per unit time.

The actual rate of this growth depends on the growth conditions, which affect the frequency of cell division events and the probability of both daughter cells surviving.

Under controlled conditions, the cyanobacteria population can be doubled four times a day and then tripled. However, this exponential growth eventually comes to an end when the medium becomes depleted of nutrients and enriched with waste. The final phase is the death phase. Bacterial death can be the result of lack of nutrients, environmental temperature above or below the tolerance band for the species, or other deleterious conditions.

Modeling a cyanobacterial growth curve allows one to reduce recorded data to a limited number of parameters of interest such as the specific growth rate, lag phase duration, and maximum population density. The growth models found in the literature describe only the number of organisms and do not include substrate consumption as would a model based on the Monod equation.

However, the substrate level is not of interest in our application since we assume there to be sufficient substrate to allow cyanobacterial growth.