Aspects of the Cryobiology of the Intertidal Harpacticoid CopepodTigriopus brevicornis(O. F. Müller)

doi:10.1006/cryo.1997.2046

Cryobiology

Volume 35, Issue 4, December 1997, Pages 309-317

https://doi.org/10.1006/cryo.1997.2046 Get rights and content

Abstract

Cold-resistance studies of marine invertebrates have concentrated on intertidal sedentary organisms, which are often subjected to subzero air temperatures in winter. Mobile rock pool inhabitants have been rarely studied because such habitats are thought to buffer environmental variation. However, it is not uncommon for small upper-shore rock pools (∼2 by 1 cm) to become completely frozen. Such supralittoral habitats are subject to extreme physicochemical fluctuations especially in salinity (0 to 300‰) and temperature (−1 to +32°C) due to evaporation and dilution. The dominant invertebrate in such habitats is the harpacticoid copepodTigriopus brevicornis.Aspects of the cryobiology ofT. brevicorniswere investigated using differential scanning calorimetry (DSC). Thermograms obtained from DSC allowed determinations of freeze-onset (supercooling point, SCP), melt-onset, and melt-peak (melting point, MP) temperatures, together with estimation of the proportion of water freezing in the samples. The effects of acclimation salinity, temperature, starvation, and reproductive state on these cryobiological parameters were investigated. Acclimation to increasing salinity depressed the SCP, with the highest salinity (70‰) producing the lowest SCP, melt-onset, and MP temperatures at −27.5, −15.2, and −9.5°C respectively. The highest acclimation temperature (20°C) produced the lowest SCP (−23.4°C). Starvation significantly increased the SCP, melt-onset, and MP temperatures in comparison to fed individuals acclimated to the same salinity. The presence of eggs or ovaries in individual copepods elevated the SCP compared to nongravid females and males. LT₅₀studies showed that acclimation to high salinity improved the ability ofT. brevicornisto survive in frozen seawater. Seventy parts per thousand acclimated individuals had an LT₅₀of 64.9 h compared with just 1.4 h for 5‰ acclimated individuals in frozen seawater at −5°C. The study shows that the cold-resistance capabilities ofT. brevicorniscan be affected by several different factors, and the link between the osmoconforming nature of this species and its cold resistance is discussed.

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Impacts of extreme weather events on highly eutrophic marine ecosystem (Rogoznica Lake, Adriatic coast)
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Citation Excerpt :
Splash pools are harsh environments with wide range of T and S and are prone to evaporation. Accordingly, Tigriopus sp. shows a remarkable adaptation to changes in S, T and O2 in RL (McAllen and Block, 1997; McAllen, 1998, 1999). Also, they are omnivorous, and feed on bacteria, protozoans, detritus, diatoms and small crustaceans (Lewis et al., 1998; Gallucci and Ólafsson, 2007).
Rogoznica Lake is highly eutrophic marine system located on the Eastern Adriatic coast (43°32′N, 15°58′E). Because of the relatively small size (10,276 m²) and depth (15 m) it experiences strong natural and indirect anthropogenic influences.
Dynamics within the lake is characterized by the extreme and highly variable environmental conditions (seasonal variations in salinity and temperature, water stratification and mixing, redox and euxinic conditions, concentrations of nutrients) which significantly influence the biology inside the lake.
Due to the high phytoplankton activity, the upper part of the water column is well oxygenated, while hypoxia/anoxia usually occurs in the bottom layers. Anoxic part of the water column is characterized with high concentrations of sulfide (up to 5 mM) and nutrients (NH₄⁺ up to 315 μM; PO₄³⁻ up to 53 μM; SiO₄⁴⁻ up to 680 μM) indicating the pronounced remineralization of the allochthonous organic matter, produced in the surface waters. The mixolimnion varies significantly within a season feeling effects of the Adriatic atmospheric and ocean dynamics (temperature, wind, heat fluxes, rainfall) which all affect the vertical stability and possibly induce vertical mixing and/or turnover. Seasonal vertical mixing usually occurs during the autumn/winter upon the breakdown of the stratification, injecting oxygen-rich water from the surface into the deeper layers. Depending on the intensity and duration of the vertical dynamics (slower diffusion and/or faster turnover of the water layers) anoxic conditions could developed within the whole water column.
Extreme weather events such as abrupt change in the air temperature accompanied with a strong wind and consequently heat flux are found to be a key triggering mechanism for the fast turnover, introducing a large amount of nutrients and sulfur species from deeper parts to the surface. Increased concentration of nutrients, especially ammonium, phosphate, and silicates persisting for several months after the mixing event, together with anoxic stress conditions, additionally influence already stressed ecosystem, hence shifting the community structure and food/web interactions in this marine system.
The effect of environmental variation on the reproductive development time and output of the high-shore rockpool copepod Tigriopus brevicornis
2009, Journal of Experimental Marine Biology and Ecology
The extreme environmental changes observed in high-shore rockpools occupied by Tigriopus brevicornis, provide a significant physiological challenge that may have implications for the energetics and hence the life history characteristics of this species. The present study was designed to assess the effect of this environmental variation on the reproductive development time and output of T. brevicornis in terms of duration of the various stages in ovary and egg sac development and maturation as well as naupliar development time to the first copepodite stage and total numbers of copepodites produced.
There was a significant difference in reproductive development time and output in the three test salinities with only successful development to copepodite I stage seen in normal seawater (35 psu). There was also a successful release of nauplii seen at the low salinity (5 psu), but no subsequent survival to the copepodite I stage, whilst there was not even a development of egg sacs in the high salinity test medium (70 psu). There was also a significant difference in reproductive development times in the three test temperatures with fastest ovary development in the high temperature (23 °C) and slowest development time in the lowest temperature (5 °C). However, it should be noted that the highest number of nauplii produced was actually in the mid temperature (12 °C), not the high temperature. Exposure to hypoxic and anoxic conditions had a significantly detrimental effect on reproductive development with slower development time through the reproductive stages and no individuals surviving to copepodite stage I from the hypoxic and anoxic test conditions, but good development from the normoxic conditions.
The present study indicates that animals living in high-shore rockpools may incur a considerable energetic cost, due to the environmental changes that are characteristic of this habitat and the importance of resource allocation in these different physiological conditions is paramount to the species' survival.
Crustacea in Arctic and Antarctic Sea Ice: Distribution, Diet and Life History Strategies
2006, Advances in Marine Biology
Citation Excerpt :
To our knowledge, the cold and freezing resistances of ice‐associated copepods have not been established. However, there are some studies on the cryobiology of harpacticoid copepods sampled from supralittoral habitats that demonstrate their tolerance to freezing (e.g., McAllen and Block, 1997). As discussed earlier for amphipods, this tolerance is a result of depressing the supercooling point with increased internal salinity.
This review concerns crustaceans that associate with sea ice. Particular emphasis is placed on comparing and contrasting the Arctic and Antarctic sea ice habitats, and the subsequent influence of these environments on the life history strategies of the crustacean fauna. Sea ice is the dominant feature of both polar marine ecosystems, playing a central role in physical processes and providing an essential habitat for organisms ranging in size from viruses to whales. Similarities between the Arctic and Antarctic marine ecosystems include variable cover of sea ice over an annual cycle, a light regimen that can extend from months of total darkness to months of continuous light and a pronounced seasonality in primary production. Although there are many similarities, there are also major differences between the two regions: The Antarctic experiences greater seasonal change in its sea ice extent, much of the ice is over very deep water and more than 80% breaks out each year. In contrast, Arctic sea ice often covers comparatively shallow water, doubles in its extent on an annual cycle and the ice may persist for several decades. Crustaceans, particularly copepods and amphipods, are abundant in the sea ice zone at both poles, either living within the brine channel system of the ice‐crystal matrix or inhabiting the ice–water interface. Many species associate with ice for only a part of their life cycle, while others appear entirely dependent upon it for reproduction and development. Although similarities exist between the two faunas, many differences are emerging. Most notable are the much higher abundance and biomass of Antarctic copepods, the dominance of the Antarctic sea ice copepod fauna by calanoids, the high euphausiid biomass in Southern Ocean waters and the lack of any species that appear fully dependent on the ice. In the Arctic, the ice‐associated fauna is dominated by amphipods. Calanoid copepods are not tightly associated with the ice, while harpacticoids and cyclopoids are abundant. Euphausiids are nearly absent from the high Arctic. Life history strategies are variable, although reproductive cycles and life spans are generally longer than those for temperate congeners. Species at both poles tend to be opportunistic feeders and periods of diapause or other reductions in metabolic expenditure are not uncommon.
The effect of salinity change on the oxygen consumption and swimming activity of the high-shore rockpool copepod Tigriopus brevicornis
2001, Journal of Experimental Marine Biology and Ecology
Tigriopus brevicornis is the dominant member of the fauna in high-shore rockpools (above the mean high water of spring tides) that are subject to extreme environmental variation especially in salinity due to infrequent tidal inundation. The present study was designed to assess the effect of large-scale salinity change on the rate of oxygen consumption and levels of activity. Measurements of the rates of oxygen consumption (V_O₂) of T. brevicornis in response to simulated changes in salinity (of a magnitude that had previously been recorded in high-shore rock pools inhabited by T. brevicornis) were carried out using closed respirometry. Activity levels of T. brevicornis during exposure to three different salinities (10, 33 and 90 psu) were assessed by means of video image analysis. The study showed that T. brevicornis exhibits a reduction in activity and in oxygen consumption when exposed to higher salinities. However, individuals exposed to low salinities showed elevated rates of oxygen consumption without an associated increase in activity. The present study indicates that animals living in high-shore rockpools may incur a considerable energetic cost, due to the rapid and large-scale environmental changes that are characteristic of this habitat.
The effects of temperature and oxygen partial pressure on the rate of oxygen consumption of the high-shore rock pool copepod Tigriopus brevicornis
1999, Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Inhabitants of littoral rock pools such as the copepod Tigriopus brevicornis are subjected to highly variable physico-chemical conditions. The effect of temperature and P_O₂ on the rate of oxygen consumption of T. brevicornis from a Scottish population was studied. As expected, V_O₂ increased with increasing temperature over the range 5–30°C. However, at 0 and 35°C the rates of oxygen consumption were significantly lower than predicted. This was reflected in the very different values for Q₁₀ obtained over the temperature range 0–5°C (due to T. brevicornis entering a dormant state at 0°C) and 30–35°C (due to high mortality at 35°C), compared with the mean Q₁₀ of 2.9 for the temperature range 5–30°C. Spectrophotometric studies of the body fluids of T. brevicornis failed to detect the presence of a respiratory pigment. Nevertheless, T. brevicornis was able to maintain its rates of oxygen consumption independent of P_O₂ under conditions of declining oxygen tension. However, the ability of T. brevicornis to maintain respiratory independence under hypoxia was affected by temperature since the P_c was higher at 30°C than at lower temperatures. T. brevicornis appears to be able to withstand exposure to low temperature and to severe hypoxia by entering a quiescent or dormant state during which its metabolic rate is significantly reduced.
Heat tolerance and thermal preference of the copepod Tigriopus californicus are insensitive to ecologically relevant dissolved oxygen levels
2020, Scientific Reports

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Regular ArticleAspects of the Cryobiology of the Intertidal Harpacticoid CopepodTigriopus brevicornis(O. F. Müller)☆

Abstract

Comp. Biochem. Physiol.

Cryobiology

Estuarine Coastal Shelf Sci.

Respir. Physiol.

Comp. Biochem. Physiol.

Migration ofIllyanasa obsoleta, Littorina littoreaLittorina rudis

Nautilus

Differential scanning calorimetry in ecophysiological research

Acta Oecol.

Morphological analysis of the twoTigriopus

Natura (Milano)

Under ice biota at the Pond Inlet ice edge and in adjacent fast ice areas during spring

Arctic

Salinity tolerance, salinity preference and temperature tolerance in the high shore copepodTigriopus brevicornis

Mar. Biol.

Environmental tolerances of three species of the harpacticoid copepod genusTigriopus

J. Mar. Biol. Assoc. UK

Probit Analysis

Regular Article
Aspects of the Cryobiology of the Intertidal Harpacticoid CopepodTigriopus brevicornis(O. F. Müller)☆