Changes in macrophytes from the Barents sea littoral affected by the oil |
VOSKOBOINIKOV G. M., MAKAROV M. V., RYZHIK I. V., STEPANYAN .O.V. Algae macrophytes play a very important role in the coastal ecosystems as sources of organic matter, places for the inhabitancy and reproduction including commercial hydrobiontes.Attention paid by the researches to the oil contamination of algae-macrophytes is quite understandable, hi the Barents Sea these works acquire special significance in connection of the planned excavation, transportation and reloading of oil n the shelf and coastal zones. Which will be the consequences for the coastal phytocenoses due to the constant contamination and simultaneous discharge of oil products, is the restoration of coastal growths in case of their mortality possible and how quickly will this restoration be? In this paper comparative analysis of littoral phytocenoses (state of littoral macrophytes) from the inhabitancy places, differing by the degree of oil contamination is earned out, and morpho-functional state of algae subjected to the constant oil contamination is analyzed. Materials, methods and investigation area. To reveal oil contamination impact on the coastal phytocenoses analysis of the algae growths on the littoral of the Murmansk coast bays was earned out. The bays selected were as follows: Yaryshnaya (ecologically clean bay), Korabelnaya bay (insignificant contamination with oil products), the berths of the Lodeinoe settlement (Teriberskaya bay) and passenger port of the Murmansk city. The two latter places of algae inhabitancy are subjected to constant contamination with oil products. Morphophysiological, biochemical characteristics reflecting functional state of macrophytes were analyzed. Algae were sampled from the frames 0.25 m dimensions. Samples were repeated thrice. All samples were sorted out into species, algae biomass and abundance of dominating fucoid species were estimated.Length and weight of plants were measured in fucoids. besides, the number of dichotomous branching and vesicles on the major axis of thallus were estimated. Fucoids were divided into age groups on the basis of the number of branching (Fttats) or sets of vesicles {Ascophylhmt). Visually phytocenoses composition, projective coverage of substrate with algae were analyzed. Separately, plants of the same age-dominating algae species - Ftictis vesiailosits were compared by growth rate, photosynthesis intensity the number and ratio of pigments, total lipids, maimite and polysaccharides contents (Voskoboinikov et al., 2004; Makarov et al.. 2004). Results and discussion. For the Korabelnaya and Yaryshnaya bays like for the majority of Muniian bays a relatively dense algae coverage varying in the range 75-95 % is typical. In the algae distribution a division into belts is clearly seen, associations proceed smoothly one into another. Species composition and abundance of algae species in the upper and middle littoral depths are fucoids. Species composition and abundance of algae species on the littoral of the bays described are typical in general of the Murmansk coast. In the upper layer of the Korabelnaya bay on the boundary of littoral and sub-littoral there grows Pelvetia canaliculata, in the Yaryshnaya bay Pelvetia canaliculata occurs extremely rare. Subsequently, in the upper layer of both the bays - Fiicas vesici/losus and Ascophyllum nodosum, in the middle - F. serratus and F. ditichus. On the low ground of the middle layer a belt of red algae is observed- these are Hetlosoccion ramentaceum and Pahi/aria palmetto. On the boulders, on the boundary of sub-littoral and littoral between the red algae belts and laminaria there exists a transitional zone occupied by the association Ulvetria obsatro + Spl/acelaria etrctica + Petlmetria palmata. On the littoral the major attendant algae are as follows: among brown algae - Chorda filnm, Chordaria fletgelliformis, Dictyosiphon foeniculaceus, Elachista fucicola, Petalonia fascia, Pilayetta tttoralis. Among green algae Acrosiphonia arctet, Monostroma grevillei, Protomonostroma undulatum, Spongomorpha lanosa, Ulvetria obscura are numerous. Filamentous green algae Ulothrixflacca, Urosporapenicilliformis, Blidingia ininimania occur in small quantities. Among red algae besides pointed out above dominating species there occur also Polysiphonia wceolata. Rhodochorton purpureum, RhodomeUa lycopodioides, Ceramium rubrum, Porphyra umbilcalis, other Porphyra species. Dumontia incrassata and Chondrus crispus are registered individually. Microscopic epi and endophytes are numerous. Algae biomass is insignificant and constitutes about 8 kg/m2 (range is 3.5-24 kg/m2). On the littoral in area of berth in the Lodeinoe settlement projective algae coverage does not exceed 60 %, on the littoral of the Murmansk harbor-not more than 15 %. Among algae species in both contaminated places of inhabitancy Fucus vesiculosus (90 %) is present mainly. In the area of berth F. distichus, Ascophyllum nodosum, Pylaiettla litoralis, Enteromorpha sp., Ulvetria obscura, Petlmetria palmetto are also registered, hi the Murmansk harbor littoral only three attendant species - F. distichus, Ascophyllum nodosum, Pylaiettla litoralis are noted. Algae biomass in the berth area is approximately 2 kg/m2 that on the Murmansk harbor littoral is 0.3 kg/m2 . Comparison of Fucus vesiculosus populations from the Korabelnaya and Yaryshnaya bays of the Barents Sea show that plants of the younger age groups prevail in the latter. With increase of the plants age their abundance lowers. Similar age structure of the population is normal for the coastal Murman areas not subjected to the anthropogenie contamination, hi the Korabelnaya bay plants of senior age groups prevail. It might be supposed that anthropogenic impact affecting the algae influences first of all the younger plants. Thus, though the population develops it lacks sufficient potential as the number of young plants is significantly lowered. In the area of berth Fucus vesiculosus specimens at the age up to 5 years (approximately 20-25 %) dominate, about 3% of plants is at the age of up to 11 years old. F. distichus specimens occur at the age of up to 7 years old. Maximal number of plants in the population is 2-3 years old. On the passenger part littoral age of Fucus vesiculosus specimens does not 6 years. Photosynthesis intensity measured by the isotope method in Fucus vesiculosus specimens from the Yaryshnaya and Murmansk harbor was identical constituting 1.02±0.02mg CO2/hour g dry weight. As for composition and number of photosynthetic pigments there were no differences either. Mannite and fucoidane contents in fucus from the places with constant contamination with oil products is lower that that from the clean places, lipid contents is vice versa approximately 3 times as higher. Thus, in the places of constant contamination suppressed state and mortality of the majority of algae species impacted by oil products is revealed. In Fucus vesiculosus from the contaminated place of inhabitancy diminishing of length, weight, life duration and significant growth rate is observed. Together with this practically all specimens sampled in the places contaminated with oil products showed the ability for growth. Occurrence of Facas vesicalosus mainly on the contaminated littoral might testify on the specific resistance of this algae species to the oil contamination. Greatest resistance to the oil contamination revealed in Faais vesicalosus in comparison to other macrophytes correlates with the extremely high resistance of this species to other altering environmental factors: re-freshening, negative temperature, ultraviolet. We cannot speak now with assurance on the reasons of Facas vesicalosus resistance to oil contamination. Probably toxicant does not penetrate through the thick polysaccharide capsule and membrane into fucus cells. Several scientists are of the same opinion when they analyze the reason of brown algae resistance to contamination (Nelson-Smith, 1977). She explains significant toxicity of oil components with low molecular weight easier penetrating through the cellular capsule and great liability to impact of identical toxicants doses of plants at the early stages of development compared to the adult plants (Thelin. 1981). Another reason explaining a possibility of algae to survive in conditions of oil contamination might be their capability to include oil hydrocarbons into metabolism, which was shown on some microorganisms (Gusev. Komelli, 1982). The results above presented speak in favor of the latter hypothesis, besides we obtained the data that oil concentration in Facas vesiculosus growing in the contaminated places might be 50 times as higher that in algae of the same species from the clean place of inhabitancy. References ARCTIC SHELF OIL AND GAS CONFERENCE 2004
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