Conditions In Marine Ecosystems Research Articles

Spatial and temporal changes in cumulative human impacts on the world's ocean.

Human pressures on the ocean are thought to be increasing globally, yet we know little about their patterns of cumulative change, which pressures are most responsible for change, and which places are experiencing the greatest increases. Managers and policymakers require such information to make strategic decisions and monitor progress towards management objectives. Here we calculate and map recent change over 5 years in cumulative impacts to marine ecosystems globally from fishing, climate change, and ocean- and land-based stressors. Nearly 66% of the ocean and 77% of national jurisdictions show increased human impact, driven mostly by climate change pressures. Five percent of the ocean is heavily impacted with increasing pressures, requiring management attention. Ten percent has very low impact with decreasing pressures. Our results provide large-scale guidance about where to prioritize management efforts and affirm the importance of addressing climate change to maintain and improve the condition of marine ecosystems.

An integrated ocean circulation, wave, atmosphere, and marine ecosystem prediction system for the South Atlantic Bight and Gulf of Mexico

An integrated nowcast/forecast modelling system covering the South Atlantic Bight and Gulf of Mexico (SABGOM) is in operation, utilizing sophisticated model coupling and parallel computing techniques. This three-dimensional, high-resolution, regional nowcast/forecast system provides a nowcast and an 84 h forecast of marine weather, ocean waves and circulation, and basic marine ecosystem conditions to the public via a Google Map interface. The SABGOM system runs automatically daily and supports a series of user-defined online applications. Extensive model validations were performed online against in situ and satellite-observed ocean conditions. The SABGOM system exhibits a reliable capability of providing valuable forecasts.

Functional groups of marine ciliated protozoa and their relationships to water quality

Ciliated protozoa (ciliates) play important ecological roles in coastal waters, especially regarding their interaction with environmental parameters. In order to increase our knowledge and understanding on the functional structure of ciliate communities and their relationships to environmental conditions in marine ecosystems, a 12-month study was carried out in a semi-enclosed bay in northern China. Samples were collected biweekly at five sampling stations with differing levels of pollution/eutrophication, giving a total of 120 samples. Thirteen functional groups of ciliates (A-M) were defined based on their specific spatio-temporal distribution and relationships to physico-chemical parameters. Six of these groups (H-M) were the primary contributors to the ciliate communities in the polluted/eutrophic areas, whereas the other seven groups (A-G) dominated the communities in less polluted areas. Six groups (A, D, G, H, I and K) dominated during the warm seasons (summer and autumn), with the other seven (B, C, E, F, J, L and M) dominating in the cold seasons (spring and winter). Of these, groups B (mainly aloricate ciliates), I (aloricate ciliates) and L (mainly loricate tintinnids) were the primary contributors to the communities. It was also shown that aloricate ciliates and tintinnids represented different roles in structuring and functioning of the communities. The results suggest that the ciliate communities may be constructed by several functional groups in response to the environmental conditions. Thus, we conclude that these functional groups might be potentially useful bioindicators for bioassessment and conservation in marine habitats.

Temporal distributions of microplankton populations and relationships to environmental conditions in Jiaozhou Bay, northern China

To analyse temporal distributions of microplankton populations and relationships to environmental conditions in marine ecosystems, a dataset of microplankton communities was investigated using a range of statistical methods. A total of 164 microplankton species comprising 100 microalgae and 64 ciliates were identified from 120 samples, respectively. Both planktonic microalga and ciliate assemblages showed temporal patterns and were significantly correlated between their temporal variations in abundance. The microplankton communities were characterized by 14 ciliates (e.g. Strombidium sulcatum, Tintinnopsis tubulosoides and Strombidium cheshiri) and 18 microalgae (e.g. Skeletonema costatum and Alexandrium tamarense). Multiple regression analyses showed that the interspecies correlations among these dominant species represented a complex network with a clear seasonal shift. Temporal pattern of microplankton communities was significantly correlated with the environmental variables such as temperature, salinity and nitrate nitrogen. The results suggest the clear species distribution and temporal dynamics of microplankton communities in response to environmental changes, and multivariate statistical approaches were a useful tool to reveal the species distribution patterns and complex microplanktonic interspecies correlations in marine ecosystems.

Annual variations in body-size spectra of planktonic ciliate communities and their relationships to environmental conditions: a case study in Jiaozhou Bay, northern China

The annual variations in body-size spectra of planktonic ciliate communities and their relationships to environmental conditions were studied based on a 12-month dataset (June 2007 to May 2008) from Jiaozhou Bay on the Yellow Sea coast of northern China. Based on the dataset, the body sizes of the ciliates, expressed as equivalent spherical diameters, included five ranks: S1 (5–35 μm); S2 (35–55 μm); S3 (55–75 μm); S4 (75–100 μm); and S5 (100–350 μm). These body-size ranks showed a clear temporal succession of dominance in the order of S2 (January–April) → S1 (May–July) → S4 (August–September) → S3 (October–December). Multivariate analyses showed that the temporal variations in their body-size patterns were significantly correlated with changes in environmental conditions, especially water temperature, salinity, dissolved oxygen concentration (DO) and nutrients. In terms of abundance, rank S2 was significantly correlated with water temperature, DO and nutrients, whereas ranks S4 and S5 were correlated with the salinity and nutrients respectively (P < 0.05). These results suggest that the body-size patterns of planktonic ciliate communities showed a clear temporal pattern during an annual cycle and significantly associated with environmental conditions in marine ecosystems.

Environmental impacts on the benthic foraminiferal fauna in nearshore ecosystems

This review presents data on how natural and anthropogenic factors affect species composition, abundance, and test morphology of benthic foraminifera of the world oceans. Major emphasis is placed on high sensitivity of foraminifera to changes in the state of the environment, particularly in nearshore zones under anthropogenic impact. It is shown that benthic foraminifera can provide indicators of environmental conditions in marine ecosystems. The effects of mollusk and salmon aquaculture activities on the composition and distribution of foraminifera are considered. It is stressed that a distinction must be made between foraminiferal test morphology variations in response to natural and anthropogenic impacts.

Marine Birds as Indicators of Arctic Marine Ecosystem Health: Linking the Northern Ecosystem Initiative to Long-Term Studies

Marine birds are sensitive indicators of the condition of marine ecosystems in the Arctic, partly because they feed at the top of the arctic food chain. The Northern Ecosystem Initiative (NEI) recently supported four separate studies that investigated aspects of Arctic marine bird science which simultaneously addressed goals of the NEI to better understand northern ecosystems and their response to environmental stressors. The projects used both scientific and traditional knowledge to examine the relationship between sea-ice, contaminants, and the ecology of marine birds, and to transfer environmental knowledge to students. Results from these investigations confirm that changes are occurring in Arctic environments, and that these are captured through marine bird research. Collectively these studies provided new data that supported NEI objectives of monitoring the health of the Arctic ecosystem, and contributed to Canada's international obligations for Arctic science.

Persistent organic pollutants in marine birds, arctic hare and ringed seals near Qikiqtarjuaq, Nunavut, Canada

The contamination of Canadian Arctic marine wild-life by persistent organic pollutants (POPs) has beenknown since the early 1970s (reviewed in Muir et al.,1992, 1999; Jensen et al., 1997; AMAP, 1998). Thesecompounds typically arrive via long range transportfrom source areas in tropical or temperate regions,and are deposited in the Arctic by condensing, cool,polar air (Bright et al., 1995; Jensen et al., 1997). Onceassimilated into the lower parts of marine food chains,these lipophilic compounds biomagnify with increasingtrophic level, and can reach concentrations in top pred-ators that can be deleterious to reproduction or survival(Jensen et al., 1997; Dietz et al., 2000; Borga˚ et al., 2001;Bustnes et al., 2003).After the initial discovery of POPs in Arctic wildlife(once thought to be too distant from sources to be pol-luted), monitoring programs were established to trackcontaminant levels in various wildlife groups. Becausethey are long-lived, forage over large areas, and areoften colonial and thus easy to sample, marine birdsintegrate many aspects of local marine ecosystem condi-tions and have proven to be particularly effective bio-indicators of marine pollution (e.g. Braune et al., 2002).In the Canadian Arctic, concentrations of many POPsin marine birds decreased from the 1970s through the1980s, and then levelled off by the 1990s (Muir et al.,1999; Braune et al., 2001). Despite a general pattern ofdecline, however, there remain clear regional differences,with some sites continuing to support wildlife with con-siderably higher contaminant concentrations than otherlocales (Muir et al., 1999; Braune et al., 2002). Manygaps remain in our geographic knowledge of contami-nant levels in Arctic wildlife tissues.Contamination of Arctic wildlife has been a key con-cern to Inuit (the aboriginal residents of the CanadianArctic), because harvest of wild animals is the principalsource of meat and an important cultural activity (Jen-sen et al., 1997). During our seabird research near twolarge colonies southeast of Qikiqtarjuaq (formerlyBroughton Island), Nunavut (Fig. 1) on eastern BaffinIsland, the community expressed concern over possiblecontamination of wildlife near the colonies, which werelocated close to two former military sites (Durban andPadloping islands). To address community concerns,evaluate the possibility of point-source contaminationin the local marine food chain, and fill in a large geo-graphic gap for contaminant data in Nunavut, weEdited by Bruce J. RichardsonThe objective of BASELINE is to publish short communications on different aspects of pollution of the marineenvironment. Only those papers which clearly identify the quality of the data will be considered for publication.ContributorstoBaselineshouldreferto‘Baseline—TheNewFormatandContent’(Mar.Pollut.Bull.42,703–704).

Growth of Vibrio cholerae O1 in red tide waters off California.

Vibrio cholerae serotype O1 is autochthonous to estuarine and coastal waters. However, its population dynamics in such environments are not well understood. We tested the proliferation of V. cholerae N16961 during a Lingulodinium polyedrum bloom, as well as other seawater conditions. Microcosms containing 100-kDa-filtered seawater were inoculated with V. cholerae or the 0.6- micro m-pore-size filterable fraction of seawater assemblages. These cultures were diluted 10-fold with fresh 100-kDa-filtered seawater every 48 h for four cycles. Growth rates ranged from 0.3 to 14.3 day(-1) (4.2 day(-1) +/- 3.9) for V. cholerae and 0.1 to 9.7 day(-1) (2.2 +/- 2.8 day(-1)) for bacterial assemblage. Our results suggest that dissolved organic matter during intense phytoplankton blooms has the potential to support explosive growth of V. cholerae in seawater. Under the conditions tested, free-living V. cholerae was able to reach concentrations per milliliter that were up to 3 orders of magnitude higher than the known minimum infectious dose (10(4) cell ml(-1)) and remained viable under many conditions. If applicable to the complex conditions in marine ecosystems, our results suggest an important role of the growth of free-living V. cholerae in disease propagation and prevention during phytoplankton blooms.

Indicators for assessing the sustainability of Australia's marine ecosystems

Principles of integrated ecosystem-based management have been used to derive 61 potential environmental indicators for reporting on Australia’s marine and estuarine ecosystems. They are focused on tracking the condition of marine ecosystems in the face of a variety of uses and pressures, and are consistent with approaches used for assessment of public- and private-sector environmental activities, and with the international standard. The in icators cover issues in protected species, common habitats, renewable and non-renewable resources, water and sediment quality, and integrated management. Gaps in knowledge and technical capacity include: knowledge of the nature of the ecosystems is incomplete (ineffective indicators may be selected); scientific understanding of environmental issues is limited (the wrong cause may be identified); the resolving capacity of a monitoring programme cannot be determined (monitoring may falsely infer that no changes have occurred, or provide an answer to the wrong question); procedures for synthesis and aggregation of data across spatial, temporal and taxonomic scales, or for estimating uncertainty in national summaries are lacking; case-study trials, reference sites, and suitable interpretative models are needed; and an established procedure for revising and updating the indicators as new knowledge accrues, or if new issues arise, is lacking.