Pseudocalanus newmani

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Pseudocalanus newmani
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Subphylum:
Crustacea
Class:
Maxillopoda
Subclass:
Copepoda
Order:
Calanoida
Family:
Clausocalanidae
Genus:
Pseudocalanus
Species:
P. newmani
Binomial name
Pseudocalanus newmani
Frost, 1989

Pseudocalanus newmani is a copepod found in Arctic and northern Pacific waters. It was described by Frost in 1989. It is found in the Arctic and surrounding waters. There are multiple generations. Unlike some copepods, P. newmani undergoes reverse diel vertical migration, descending during the night, and ascending during the day, although it may undergo normal or no migration at all depending on predation. This copepod is primarily herbivorous.

Contents

Taxonomy

P. newmani was originally described by Frost in 1989 from multiple samples caught in the main basin of Puget Sound. Its specific name references Bill H. Newman. [1]

Description

Female P. newmani usually range in length from about 0.9 to 1.5 millimetres (0.035 to 0.059 in), and the male is generally between about 0.8 and 1.2 millimetres (0.031 and 0.047 in). [2] The female is distinguished from other species by its rounded cephalosome, which is barely anterior to the rostrum. It is also distinguished by its urosomal segments being the longest in its genus relative to cephalosome length. The male is distinguished by having a ratio of basal to coxal segments of the fourth leg being less than 1.5. Additionally, the male lacks sensilla on the mediodorsal portion of the second to fourth urosomal segments. [1]

Distribution

P. newmani is found in the Arctic, the northern Pacific, and in the Atlantic off of the eastern coast of Canada and Maine. It is also found in the Hudson Bay. [2]

Ecology

Life cycle and reproduction

In Toyama Bay, P. newmani reproduces and actively grows between February and April. During this time, there are three generations. The period of reproduction and growth corresponds to the time when water temperatures are lowest at the top 100 metres (330 ft) (around 10 to 12 °C (50 to 54 °F)), and the abundance of phytoplankton reaches its maximum. [3] Females can generally produce anywhere from one to four eggs per day when breeding. [4] In Toyama Bay, after a reproduction event in 1990, there were no copepods of this species found until November. This corresponded with surface water temperatures above 15 °C (59 °F). This, along with a lack of large lipid stores, likely indicates that it cannot migrate to cooler waters and enter diapause. [3] Additionally, it develops quicker in warmer waters until temperatures of at least 15 °C (59 °F). [5] At Dabob Bay, the population recovery occurs earlier, around July. [4] The abundance of this copepod, at least in the Dabob Bay, is related to the abundance of predators, especially the predatory chaetognath Sagitta elegans . [6]

P. newmani usually undergoes reverse diel vertical migration, ascending in the day, and descending in the night, a reversal of normal diel vertical migration. The reason for this is because of predators (such as omnivorous copepods that have normal diel vertical migration) being more abundant during the night. When predators are not present in large numbers, it usually does not descend at night, instead constantly staying at the surface. [7] This has fitness benefits, as clutches developed in deeper waters have decreased survivorship. [8] But, when predators are found at the surface during the day, P. newmani experiences normal diel vertical migration. [7] It can switch between migration strategies quickly, sometimes in under five weeks. [9] As a whole, this migration (normal or otherwise) does not seem to be undertaken by copepodite stage I through III, likely because they have lower mortality rates. [7] When predation is not a factor, this copepod prefers to reside in the layers with the most chlorophyll a. [10]

Feeding

P. newmani is mainly herbivorous, [4] and feeds continuously, with an increased intake during the night. [11] It prefers centric diatoms, even though aldehydes of the diatom genus Thalassiosira , for example, can be toxic to its young in large quantities. [4] This is seen in the reduced reproductive success (both in terms of hatching success and naupliar viability) of P. newmani fed exclusively diatoms in the laboratory, and the reduced success of this copepod during Thalassiosira blooms. [4]

Predators

P. newmani has multiple predators, and adjusts its behaviour around them. One predator is the copepod Euchaeta elongata , which (in females, as least) likely can consume 19 adults of P. newmani each day. The chaetognath Sagitta elegans, another predator of this copepod, can ingest up to about five females per day. An adult Euphausia pacifica can attack, on average, about two female P. newmani per day. Three-spined stickleback, juvenile chum salmon, and other planktivorous fish can attack this copepod. In response to the normal diel vertical migration of predators like Euchaeta elongata, it performs a reverse diel vertical migration so as to not co-occur in depth with feeding predators. It may also perform normal diel vertical migration when visually-reliant predators are more important, and no migration when predators do not have a large enough effect. [7]

Related Research Articles

Zooplankton Heterotrophic protistan or metazoan members of the plankton ecosystem

Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word zooplankton is derived from the Greek zoon (ζῴον), meaning "animal", and planktos (πλαγκτός), meaning "wanderer" or "drifter". Individual zooplankton are usually microscopic, but some are larger and visible to the naked eye.

Holoplankton

Holoplankton are organisms that are planktic for their entire life cycle. Holoplankton can be contrasted with meroplankton, which are planktic organisms that spend part of their life cycle in the benthic zone. Examples of holoplankton include some diatoms, radiolarians, some dinoflagellates, foraminifera, amphipods, krill, copepods, and salps, as well as some gastropod mollusk species. Holoplankton dwell in the pelagic zone as opposed to the benthic zone. Holoplankton include both phytoplankton and zooplankton and vary in size. The most common plankton are protists.

Firefly squid Species of cephalopod also known as the sparkling enope squid

The firefly squid, also commonly known as the sparkling enope squid or hotaru-ika in Japan, is a species of squid in the family Enoploteuthidae. It is the sole species in the monotypic genus Watasenia. These tiny squid are found on the shores of Japan in springtime during spawning season, but spend most of their life in deeper waters between 200 and 400 metres. They are bioluminescent organisms and emit blue light from photophores, which some scientists have hypothesized could be used for communication, camouflage, or attracting food, but it is still unclear in the scientific community exactly how this species uses their bioluminescence. The firefly squid is a predator and actively hunts its food, which includes copepods, small fish, and other squids. The lifespan of a firefly squid is about one year. At the end of their lives females return close to shore to release their eggs, then die shortly thereafter. This mass migration of firefly squid to the shore is a lucrative business for Japanese fishermen, and during spawning season many go out to the bays to collect the dying squid. Many more also visit Japan during spawning season to see the bright blue light created from the firefly squid's bioluminescence light up the bay, making their spawning season not only a fishing opportunity but also a tourist attraction.

Diel vertical migration A pattern of daily vertical movement characteristic of many aquatic species

Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The migration occurs when organisms move up to the uppermost layer of the sea at night and return to the bottom of the daylight zone of the oceans or to the dense, bottom layer of lakes during the day. The word diel comes from the Latin dies day, and means a 24-hour period. In terms of biomass, it is the greatest migration in the world. It is not restricted to any one taxon as examples are known from crustaceans (copepods), molluscs (squid), and ray-finned fishes (trout). Various stimuli are responsible for this phenomenon, the most prominent being response to changes in light intensity, though evidence suggests that biological clocks are an underlying stimulus as well. The phenomenon may arise for a number of reasons, though it is most typically to access food and avoid predators. While this mass migration is generally nocturnal, with the animals ascending from the depths at nightfall and descending at sunrise, the timing can be altered in response to the different cues and stimuli that trigger it. Some unusual events impact vertical migration: DVM is absent during the midnight sun in Arctic regions and vertical migration can occur suddenly during a solar eclipse.

<i>Calanus finmarchicus</i> Species of crustacean

Calanus finmarchicus is a species of copepods and a part of zooplankton, which is found in enormous amounts in the northern Atlantic Ocean.

<i>Chrysaora hysoscella</i>

Chrysaora hysoscella, the compass jellyfish, is a common species of jellyfish that inhabits coastal waters in temperate regions of the northeastern Atlantic Ocean, including the North Sea and Mediterranean Sea. In the past it was also recorded in the southeastern Atlantic, including South Africa, but this was caused by confusion with close relatives; C. africana, C. fulgida and an undescribed species tentatively referred to as "C. agulhensis".

<i>Acartia</i>

Acartia is a genus of marine calanoid copepods. They are epipelagic, estuarine, zooplanktonic found throughout the oceans of the world, primarily in temperate regions.

Calanus helgolandicus is a copepod found in the Atlantic, from the North Sea south to the western coast of Africa. The female has an average size of about 2.9 millimetres (0.11 in) and the male has an average size of about 2.7 millimetres (0.11 in).

Calanus pacificus is a species of copepod found in the Pacific Ocean. The female has an average length of about 3.1 millimetres (0.12 in), and the male has a value of about 2.9 millimetres (0.11 in).

<i>Calanoides acutus</i> Species of crustacean

Calanoides acutus is a copepod found in Antarctica and the surrounding waters.

Neocalanus plumchrus is a large copepod found in the Pacific and Arctic Oceans. It was described in 1921 by Marukawa. N. flemingeri used to be placed in this species, likely as a form, until it was split in 1988 by Charles B. Miller.

Metridia pacifica is a copepod found in the north Pacific and surrounding waters.

Eucalanus bungii is a copepod found in the north Pacific and surrounding waters.

Calanus sinicus is a copepod found in the northwest Pacific.

Rhincalaus nasutus is a copepod in the family Rhincalanidae.

<i>Paracalanus parvus</i> Species of crustacean

Paracalanus parvus is a copepod found throughout the world, except the Arctic.

Pseudocalanus elongatus is a copepod found primarily in the Atlantic Ocean.

Metridia gerlachei is a copepod found primarily in Antarctic and sub-Antarctic waters.

Pseudocalanus minutus is a small copepod found in the Arctic Ocean and surrounding waters.

Euchaetidae Family of crustaceans

Euchaetidae is a family of marine copepods. The family is cosmopolitan and occurs in all the oceans, including the Southern and Arctic Oceans. Euchaetidae are medium to large-sized copepods.

References

  1. 1 2 Frost, B. W. (1989). "A taxonomy of the marine calanoid copepod genus Pseudocalanus". Canadian Journal of Zoology. 67 (3): 525–551. doi:10.1139/z89-077. ISSN   0008-4301.
  2. 1 2 Razouls C.; de Bovée F.; Kouwenberg J.; Desreumaux N. (2018). "Diversity and Geographic Distribution of Marine Planktonic Copepods". Sorbonne Université, CNRS. Retrieved 24 July 2018.
  3. 1 2 Yamaguchi, Atsushi; Ikeda, Tsutomu; Shiga, Naonobu (1998). "Population structure and life cycle of Pseudocalanus minutus and Pseudocalanus newmani (Copepoda: Calanoida) in Toyama Bay, southern Japan Sea". Plankton Biology and Ecology. 45 (2).
  4. 1 2 3 4 5 Halsband-Lenk, Claudia; Pierson, James J.; Leising, Andrew W. (2005). "Reproduction of Pseudocalanus newmani (Copepoda: Calanoida) is deleteriously affected by diatom blooms – A field study". Progress in Oceanography. 67 (3–4): 332–348. doi:10.1016/j.pocean.2005.09.003. ISSN   0079-6611.
  5. ↑ Lee, H.-W.; Ban, Syuhei; Ikeda, Tsutomu; Matsuishi, Takashi (2003). "Effect of temperature on development, growth and reproduction in the marine copepod Pseudocalanus newmani at satiating food condition". Journal of Plankton Research. 25 (3): 261–271. doi: 10.1093/plankt/25.3.261 . ISSN   1464-3774.
  6. ↑ Ohman, M.D. (1986). "Predator-limited population growth of the copepod Pseudocalanus sp". Journal of Plankton Research. 8 (4): 673–713. doi:10.1093/plankt/8.4.673. ISSN   0142-7873.
  7. 1 2 3 4 Ohman, Mark D. (1990). "The demographic benefits of diel vertical migration by zooplankton". Ecological Monographs. 60 (3): 257–281. doi:10.2307/1943058. ISSN   0012-9615. JSTOR   1943058.
  8. ↑ Ohman, M. D.; Frost, B. W.; Cohen, E. B. (1983). "Reverse diel vertical migration: An escape from invertebrate predators". Science. 220 (4604): 1404–1407. doi:10.1126/science.220.4604.1404. ISSN   0036-8075. PMID   17730658. S2CID   28892491.
  9. ↑ Frost, Bruce W.; Bollens, Stephen M. (1992). "Variability of diel vertical migration in the marine planktonic copepod Pseudocalanus newmani in relation to its predators". Canadian Journal of Fisheries and Aquatic Sciences. 49 (6): 1137–1141. doi:10.1139/f92-126. ISSN   0706-652X.
  10. ↑ Pierson, James J.; Leising, Andrew W.; Halsband-Lenk, Claudia; Ferm, Nissa (2005). "Vertical distribution and abundance of Calanus pacificus and Pseudocalanus newmani in relation to chlorophyll a concentrations in Dabob Bay, Washington". Progress in Oceanography. 67 (3–4): 349–365. doi:10.1016/j.pocean.2005.09.006. ISSN   0079-6611.
  11. ↑ Dagg, M.J.; Frost, B.W.; Newton, J. (1998). "Diel vertical migration and feeding in adult female Calanus pacificus, Metridia lucens and Pseudocalanus newmani during a spring bloom in Dabob Bay, a fjord in Washington USA". Journal of Marine Systems. 15 (1–4): 503–509. doi:10.1016/S0924-7963(97)00093-6. ISSN   0924-7963.
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