Plankton biodiversity has fascinated ecologists for the past few decades. It has become a major topic of research in plankton ecology since many aquatic creatures rely on it. Although principle of competitive exclusion tells us that the number of surviving species cannot exceed the number of limiting resources at equilibrium, still many species coexist for limited number of resources. Also, in the famous paper “The paradox of plankton”, Hutchinson (1961) first posed the classical problem “... how it is possible for a number of species to coexist in a relatively isotropic or unstructured environment all competing for the same sorts of materials”. However, it has been suggested that in isotropic environment non-equilibrium dynamics driven by several …show more content…
In spite of several attempts to solve the paradox of plankton, a general mechanism, that alone can explain the diversity of phytoplankton in laboratory, fresh water and marine ecosystems, is still an unreached goal.
Toxic or allelopathic compounds released by some species of plankton have a great impact on plankton ecosystem. Allelochemical interations between dif- ferent populations can have different ecological consequences. There are ev- idence for allelopathy as a mechanism for interference competition between different species of zooplankton (Folt and Goldman, 1981). It is observed that, allelopathy reduces the competitive effectiveness among phytoplankton species
(Hulot and Huisman, 2004; Sol ́ et al., 2005). It also prevents competitive ex- e clusion among phytoplankton species. Roy and Chattopadhyay (2007b) showed that toxin-allelopathy of a third species helps in the coexistence of two other non-toxic phytoplankton species whereas in the absence of allelopathy weak competitor among them would have extinct. Analyzing marine phytoplankton data, Roy (2009) found that presence of toxic phytoplankton can be helpful in increasing diversity of non-toxic phytoplankton. In this work, using a
Dinoflagellates are one of the four main types of phytoplankton, which are photosynthetic, single celled and free living organisms in the ocean. Dinoflagellates cause the Harmful Algal Blooms (HAB) also known as the red tide effect (Hackett et al 2004). Toxicity persisting at upper levels of the food chain is detected in them from the ones which are toxic, but not all such blooms are toxic. Enhanced detection capabilities may in part contribute to observed high frequency and severity of toxic blooms. As they are also important in the health of coral reefs their study has gained significant interest. Species are often selected for genome sequencing based on their importance as a model organism or relevance to human health, such as the HAB case.
Cephalopods are known to be exceptionally intelligent by invertebrate standards and in some respects even rival “higher” vertebrates. These animals have many highly evolved sensory and processing organs that allow them to gain a greater understanding of their environment and their place within it. Due to their advanced structures, many of which are analogous to vertebrate structures, and abilities they have been widely studied. Their methods of learning have been of prime interest and many experiments have been conducted to determine the different ways in which octopuses can learn. From these experiments four main kinds of learning have been identified in octopuses: associative learning, special learning,
The Chesapeake Bay is the nation’s largest estuary with six major tributaries, the James, the Potomac, the Susquehanna, the Patuxent, the York, and the Rappahannock Rivers, feeding into the bay from various locations in Maryland, Virginia, Pennsylvania, and the District of Columbia (Chemical Contaminants in the Chesapeake Bay – Workshop Discussion 1). These areas depend on the Bay as both an environmental and an economic resource. Throughout the last 15 years the Chesapeake Bay has suffered from elevated levels of pollution. Nitrogen and phosphorous from wastewater treatment plants, farmland, air pollution, and development all lead to reduced water clarity and lowered oxygen levels, which harm fish, crabs, oysters and underwater grasses (Key Commission Issues 1). There are other types of pollution in the bay such as toxic chemicals, but because nutrient pollution is the most significant and most widespread in the Bay its effects are the most harmful to fisheries. Nitrogen and phosphorous fuel algal blooms which cloud the water and block sunlight from reaching underwater grass beds that provide food and habitat for waterfowl, juvenile fish, blue crabs, and other species (Blankenship 11-12). Algae plays a vital role in the food chain by providing food for small fish and oysters. However, when there is an overabundance of algae it dies, sinks to the bottom of the Bay, and decomposes in such a manner that depletes the oxygen levels of the Bay (11). The reduced oxygen levels in the Bay reduce the carrying capacity of the environment and these “dead areas” sometimes kill off species that can not migrate to other areas of the Bay, such as oysters (11). Increased abundance of algal blooms also led to the overabundance of harmful and toxic algae species and microbes such as the microbe Pfiesteria, which was responsible in 1997 for eating fish alive and making dozens of people sick (12). The heightened awareness of diseases that can be contracted through consumption of contaminated fish also has an economic impact. Therefore, the excess levels of nitrogen and phosphorous have fueled an overabundance of algal blooms, which has reduced water clarity and lowered oxygen levels, affecting many species within the bay and ultimately the industries that rely on these species.
The invertebrate larvae's primary food source comes from the phytoplankton that is found in abundance at the bottom of the sea floor. The larvae fed with detritus were compared with those fed on equal concentrations of phytoplankton. Other tests were conducted to compare the degrees of survivorship among the larvae using varying concentrations of phytoplankton. Higher concentrations of phytoplankton, consumed by the larvae, yielded. higher survivorship in growth and development.
Over the past years, due to warming waters, a toxic kind of algae called Pseudo-nitzschia has been blooming. This toxic algae affects sea life, especially marine mammals such as sea lions, which die of brain disease after feeding on this algae. This research paper will provide the reader with a conclusion in respect to what causes algal blooms and how we can prevent them.
For a species to survive and flourish within a given environment, it not only needs to replace itself but also all the other species around it exclusively. Hence, if one species completely replaces another species, the result is a single dominant species, a monoculture (source 2). According to Gause’s law, every species in a given environment occupies different niches for survival. Therefore, two separate species competing for similar resources cannot fundamentally coexist (source Gause). This is known as the competitive exclusion principle. When comparing animal niche’s to that of different autotrophic plants, one can rather easily differentiate adequate ecological niches for the animal species merely based on food-requirements (P.J. Grubb). On the contrary, many autotrophic plants contradict the competitive exclusion principle by sharing similar ecological niches such as sunlight, carbon dioxide, water, and alike mineral nutrients (p.j. grubb).
According to NOAA phytoplankton are microscopic organisms that continuously convert sunlight and nutrients into living tissue. Phytoplankton can be harmful to the bay because they at an uncontrollable rate causing harmful algae blooms when there is an abundance of nutrients. Phytoplankton also serve as the main food source for a larger but still microscopic organism named Zooplankton. Marine Bio.org did a study on zooplnkton revealing that they are very weak swimmers making them an easy food source for any larger organsim. Zooplanktons’ main purpose serves as the main food source for small fish and
The agriculture industries have affected the marine life due to eutrophication. Eutrophication occurs when human activity water because of the chemicals, nitrogen and phosphorus which run off into the water. Eutrophication results in algal bloom. An algal bloom forms when lots of nitrogen and phosphorus are set inside a body of water which results in an excess amount of algae in lakes, oceans, or streams. The waters can not take in a lot of algae because in can affect the habitat of the animals. It can also affect the population of the sea animals.
In Chinese tradition, Shark fin soup is called as “a celebration soup”, which people eat it to celebrate in various occasions. Moreover, people also believed that shark fin consisted of diverse nutrition values which provide them virility, wealth, and power(Wolchover, 2011). These beliefs lead to the beginning of poaching for sharks, the top of food chain in the sea world. Surprisingly, although people are aware of the decreasing number of sharks since the old days, around hundred million of sharks are still hunted each year(Heltus, 2013), to be served on luxury tables surrounded by those believers in things that they do not even prove whether the belief is reliable. Therefore, in the generation that people are mostly educated, sharks should no longer have to be continuously killed for their fins.
...of sodium cyanide is released into a target area in order to stun fish. This method of fishing is used mainly for the capture of aquarium fish, to be sold to wealthier countries, but it is also used for catching food fish. Hundreds of thousands of pounds of cyanide are released into the Pilipino reefs each year. As you can imagine, pumping large quantities of toxins into a fragile ecosystem has negative effects. Even low concentrations of cyanide inhibits photosynthesis in zooxanthellae, a genus of algae with which coral grows symbiotically. The death of the algae removes the major food source of the coral, causing bleaching and death. The cyanide also harms the coral directly, blocking the oxygen-transporting proteins, and preventing oxygen from reaching the cells, causing death.
Ciguatoxin originates from dinoflagellate algae and most commonly from the coral reef species of algae called Gambierodiscus toxicus primarily in tropical and subtropical regions (Kipping, Eastcott, Sarangi, 2006). The algae are eaten by herbivorous fishes that absorb the toxin without any significant observable effect (Kipping, Eastcott, Sarangi, 2006). The toxins remain in all parts of the fish flesh but there are higher concentrations of toxin in the viscera, liver and gonads. Bioaccumulation occurs as ciguatoxin progresses up the food chain. The species of fish with the highest quantity of ciguatoxin are the larger predators, primarily sharks and barracouda (Dickey, Plakas, 2010). The process of digestion itself appears to potentiate the toxicity (Kipping, Eastcott, Sarangi, 2006). The toxin is odorless and tasteless. Contaminated fish have no distinct taste and are undetectable (Bavastrelli, Bertucci, Midulla, Giardini, & Sanguigni, n.d.). The ciguatera toxins are heat stable and thus are not destroyed by cooking, freezing or acid (Kipping, Eastcott, Sarangi, 2006). Pre-market testing for the presence of CTX is currently not possible due to a lack of existing rapid field testing methods (Report, 2013).
These results agree with the hypothesis that our “untouched and super-productive world” is affecting marine life ecosystems (Vannela, 2012). All of these results combined confirm the overall hypothesis that pollution is getting worse in the ocean and more marine life ecosystems are being affected, but there
Did you know that more than 90 percent of all organisms that have ever lived on Earth are extinct? According to Pandey, the author of Humans Pushing Marine Life toward ‘Major Extinction’, nearly 10,000 species go extinct each year, and this rate is estimated to be 1,000 times higher than the natural extinction rate (1). Human beings are causing irreversible damage to the oceans and their wildlife, which is being led by two major reasons: Commercial fishing or over-fishing, which damaged the marine environment and caused a loss in the marine life diversity, and pollution, which is a primary way of the extinction causes that drastically modifies the marine life habitat. As a result of the commercial fishing and pollution, many of the marine species will start disappearing of the oceans. Briggs emphasizes that over-fishing “has induced population collapses in many species. So instead of having less than a hundred species at risk, as was the case some 30-40 years ago, there are now a thousand or more (10).”