Different preference reactions of three Lake Baikal endemic amphipods to temperature and oxygen are correlated with symbiotic life

Abstract

Thermopreference reactions and avoidance sensitivity to dissolved oxygen levels were measured in three endemic amphipod species from Lake Baikal: Eulimnogammarus verrucosus and E. vittatus, as well as Brandtia parasitica, which is a symbiont of the Baikalean sponge, Lubomirskia baikalensis. The benthic E. vittatus and E. verrucosus demonstrated highly developed thermopreference reactions, whereas B. parasitica did not show thermopreference behaviour. The experimental results also showed that E. vittatus and E. verrucosus avoid water with decreased dissolved oxygen levels, whereas behavioural reactions of B. parasitica did not depend on oxygen concentration. In the presence of sponge fragments, individual B. parasitica moved actively towards them, and concentrated on those fragments. Possible reasons for reduction of behavioural preference in B. parasitica are discussed with a focus on the species' symbiotic status. RÉSUMÉLes réactions de préférences à la température et la sensibilité d'évitement par rapport aux niveaux d'oxygène dissous ont été mesurées chez trois espèces d'amphipodes endémiques du lac Baïkal: Eulimnogammarus verrucosus et E. vittatus, ainsi que Brandtia parasitica, qui est un symbiote de l'éponge endémique Lubomirskia baikalensis. Les espèces benthiques E. vittatus et E. verrucosus ont démontré des réactions de préférences à la température hautement développées, tandis que B. parasitica n'en montrait pas. Les résultats expérimentaux ont aussi montré que E. vittatus et E. verrucosus évitaient l'eau ayant des niveaux bas d'oxygène dissous, tandis que les réactions comportementales de B. parasitica ne dépendaient pas de la concentration en oxygène. En présence de fragments d'éponge, les individus de B. parasitica se déplaçaient activement vers eux, et se concentraient sur ces fragments. Les possibles raisons de la réduction des préférences comportementales chez B. parasitica sont discutées avec une attention particulière au statut symbiotique de l'espèce.

Recent ecological change in ancient lakes

“…For example, in Lake Victoria, decreased water clarity has impacted reproduction by endemic cichlids, leading to the disappearance of dozens of species (Seehausen et al 1997(Seehausen et al , 2003. In Lake Baikal, littoral algal blooms have recently been recognized as threatening the extraordinary diversity of the nearshore benthos (Timoshkin et al 2016(Timoshkin et al , 2018 and in Lake Tahoe, gradual decreases in water clarity appear to have precipitated declines of endemic deepwater macrophyte-invertebrate associations (Caires et al 2013). In Lakes Valencia, Titicaca, and Victoria, pronounced (c) Land use in 2010 in lake catchments.…”

“…While there have been relatively few studies of EOCs in ancient lakes, many of these compounds are likely present due to the adjacent human settlements and activities such as recreation, fishing, agriculture, and aquaculture. In Lake Baikal, organochlorines associated with the cleaning of railway cars are the suspected cause of gastropod "cemeteries," which have been observed on the northern shore (Timoshkin et al 2016). In Lake Victoria, residues of banned organochlorine and organophosphorus pesticides have been detected (Musa et al 2011), along with elevated concentrations of estrogen compounds (Mdegela et al 2014).…”

Optical diagnostic test of stress conditions of aquatic organisms

“…Amphipods are especially variable in Lake Baikal with more than 260 endemic species inhabiting all types of substrata and depth strata [31]. The majority of the Baikal amphipods are ecologically specialized to different conditions within the lake [32], and not characterized by species diversity only, but also by a great variability of adaptive abilities [33].…”

Changes of cellular stress response relatedhsp70andabcb1transcript and Hsp70 protein levels in Siberian freshwater amphipods upon exposure to cadmium chloride in the lethal concentration range

“…Expression levels in controls are shown as dotted (mean) and dashed (standard deviations) lines. Significant differences between treatments and respective controls are indicated by *(p < 0.05; refer to (Timofeyev, Shatilina & Stom, 2001;Timofeyev & Shatilina, 2007). It thus seems possible that E. cyaneus and G. lacustris may have been metabolically more depressed at the experimental temperature than E. verrucosus and E. vittatus.…”