Loss of genetic diversity in Harpacticoida near offshore platforms

Abstract

Offshore oil and gas production platforms can be a source of chronic stress that could lead to sublethal impacts on resident benthic organisms. In June 1993 and January 1994, genetic diversity of Harpacticoida (Copepoda) living proximal to operating, offshore platforms in the Gulf of Mexico was estimated to test if platforms are associated with strong selective pressures. Because harpacticoids have short generation times and direct benthic development, they are suitable organisms for examining population responses. Genetic diversity was estimated by comparing restriction fragment length polymorphisms generated from mitochondrial DNA amplified by the polymerase chain reaction on individuals of five species (Cletodes sp., Enhydrosoma pericoense, Normanella sp., Robertsonia sp., and TachidielIa sp.). Populations living at Near regions (stations < 50 m from a platform) had significantly less haplotype diversity than populations of the same species living at Far regions (stations > 3 km from a platform). The levels of haplotype diversity exhibited by the Far populations were similar at three different platforms located hundreds of kilometers apart. The differences in haplotype diversity between Near and Far regions were the result of a higher proportion of dominant haplotypes, and a loss of less common haplotypes. Haplotypic diversity was inversely correlated with a multivariate measurement of levels of sediment contaminants. The pattern of haplotype diversity on the Gulf of Mexico continental shelf seems to consist of a uniform level of haplotype diversity, punctuated by islands of lower diversity around oil and gas platforms. The selective pressures that lead to a loss of genetic diversity may be the result of contaminants,

Organic Pollutants in Coastal Waters, Sediments, and Biota: A Relevant Driver for Ecosystems During the Anthropocene?

“…In the case of metals, Levinton et al (2003) showed that oligochaete Limnodrilus hoffmeisteri loosed genetically based resistance to Cd after cleaning of a superfund site. Another example is provided by Street and Montagna (1996) which showed reduced genetic diversity in copepods close to oil extraction platforms. Despite these isolated examples, the possibility that a genetic selection is occurring and has been occurring for the last decades should certainly be considered.…”

Towards an urban marine ecology: characterizing the drivers, patterns and processes of marine ecosystems in coastal cities

“…Further, the three drivers can have interactive effects, with potential additional consequences for marine ecosystems (see ‘Overlap, interactions and feedbacks’). Other factors relating to urbanization, such as elevated propagule pressure and invasion risk, can also be particularly intense in coastal cities (Carlton , Ruiz et al , 2000, Mineur et al , but see Tan et al and Wells et al ), however, we discuss these primarily as they relate to one or more of the three drivers presented below.…”

“…In nutrient‐rich marine estuaries, like those in most coastal cities, climate variables, such as major precipitation events and interannual fluctuations in weather patterns, tend to be particularly important drivers of temporal patterns in primary production (Mallin et al , Rodrigues and Pardal ), as these events deliver land‐based sources of nitrogen to coastal waters. However, the relationship between nutrient load and primary production is highly variable (Borum and Sand‐Jensen ), and urban‐related increases in nutrient loads can have different effects depending on tidal regimes, the system's trophic structure, as well as other factors (Alpine and Cloern , Monbet ). Nutrient loading therefore does not manifest comparable, elevated marine production across cities.…”

“…All three of the key drivers of marine urbanization are known to structure population genetics among a variety of marine taxa (examples – resource exploitation: Smith et al , Hauser et al ; pollution: Suchanek , López‐Barea and Pueyo , Nacci et al , Ma et al , Virgilio et al , Virgilio and Abbiati , McMillan et al , Galletly et al , Moraga and Tanguy ; ocean sprawl: Street and Montagna , Fauvelot et al ). In many cases, resource exploitation, pollution and ocean sprawl lead to population bottlenecks and reduced genetic diversity (Nevo et al , Maltagliati , Fauvelot et al , Ungherese et al , Neo and Todd , Pinsky and Palumbi ).…”

Processes, Assessment and Remediation of Contaminated Sediments

“…On the one hand, contamination may decrease population size (increasing the opportunity for genetic drift) or increase selection for homozygous genotypes, both of which decrease genetic variation. Indeed, some studies have clearly found reductions in genetic variation because of contamination (Street and Montagna, 1996). On the other hand, contamination may increase mutation rates at marker loci or increase selection for heterozygotes (DiBattista, 2008).…”