The effects of human-induced pollution on the replenishment of coral reefs

Coral reefs are suffering severe declines world-wide caused by multiple anthropogenic disturbances combined with natural events such as storms. Their future depends on the resilience of replenishment processes. However, few studies exist on the effects of multiple stresses on early life history of corals. This review describes coral early life history processes including reproduction, settlement and post-settlement survival. Relevant literature is then reviewed, focusing on the effects of four major human-induced threats, sedimentation, eutrophication, fishing and rising sea water temperature on reproduction, settlement and post-settlement survival. Research shows that in many cases different stresses affect the same replenishment process. Using two simple models results show that additive and synergistic stress can harm not only the energy budget of a single coral colony, but could also drive a species to extinction. A coral confronted by a disturbance may show a decrease in its energy budget due to either a change in environmental conditions such as reduced light penetration, or increased energy use for defensive mechanisms such as increased sediment rejecting activities. Adding other disturbances may reduce growth and/or reproductive output. If the energy budget decreases even further, processes involved in basal metabolism may suffer and the coral might finally die. Multiple stresses decrease maximum per capita growth of coral populations due to, for example, lower larval survival and decreased settlement success. Coral population extinctions may occur when interacting stresses are combined with Allee effects. Reduced coral densities and reduced reproductive output can lead to decreased fertilisation success. Hence, multiple stresses threaten not only adult corals, but also impact upon replenishment of coral reefs. This is a severe concern and highlights the importance of long-term studies of coral reef recovery and stress mitigation, particularly at a time where threats to reefs are expected to increase further in number, frequency and severity

Gender equality in marine sciences in Kiel, Germany: how project-funded measures can urge institutions to act

In Kiel, in the north of Germany, marine research is rooted in a lively research community hosted mainly at Kiel University and the GEOMAR Helmholtz Centre. While the ratio of women and men is more or less balanced on all qualification levels with mainly nonpermanent junior positions, women are generally underrepresented in leading research positions. The problem of gender imbalance and inequality has been well-known for a long time. Especially in the last decade, however, manifold efforts were initiated to improve gender equality on a political and institutional level as well as within the research community itself. In our article we focus on the gender equality activities of the two large externally funded marine sciences research alliances: the Cluster of Excellence “The Future Ocean” and the Collaborative Research Centre 754 “Climate–Biogeochemistry Interactions in the Tropical Ocean”. For about a decade they offered both financial provisions and a structural framework to tackle the problem of women's underrepresentation in science and came up with innovative measures. In the following case study, we not only introduce the situation of women in marine sciences in Kiel and the structural arrangement to improve gender equality in general, but we also discuss three specific measures developed within the two collaborative research projects in detail: (i) the mentoring program via:mento_ocean for female postdocs, (ii) hiring policies integrating a gender quota for recruiting postdoctoral researchers and (iii) a code of conduct. Based on these best-practice examples we can show that progress towards gender equality has been made despite some obstacles faced when implementing the measures. This was especially the case for attracting female researchers to work in Kiel marine sciences and bringing the relevance of the topic to the surface of debates within the community. Looking at gender equality activities from a managerial point of view, we conclude from the situation in Kiel, where external funding for both research alliances ended in 2019, that even time-bound activities can initiate change. Initiatives developed by the marine sciences community were taken up by other research groups and inspired new activities at the level of the institution

Influence of coral bleaching on the fauna of Tutia Reef, Tanzania

In 1998, coral reefs of Tanzania were severely affected by bleaching. The coral mortality that followed caused a concern for coral reef degradation and overall resource depletion. In this study, we investigated coral bleaching effects on the coral reef fauna at Tutia Reef in Mafia Island Marine Park, Tanzania. Corals from adjacent reef patches of the species Acropora formosa were transplanted into plots, and reef structure and associated fish assemblages were examined before and after the bleaching event. Following the coral bleaching, 88% of all corals died. A year after the event, a large proportion of the dead corals was still standing. As surviving and dead corals were from different clones, results suggested that genetic variation might influence bleaching tolerance. After the bleaching event, a change in fish community composition, with an increase in fish abundance, could be seen. Species diversity, however, was less affected. There was a correlation between structural complexity and fish densities after disturbance. This indicates that the reef may uphold an abundant fish population as long as the architectural structure is intact. The impact that the coral beaching event may have on fisheries is difficult to anticipate. The Tutia Reef supports a multi-species fishery and a variety of techniques are used. As a broad range of species are targeted, including smaller fishes, catches may not be reduced as long as the reef structure is sustained. If reef degradation follows, however, fish abundance is likely to decrease

SFB 754 data policy

This agreement is binding for all scientists within the SFB 754 and for all data collected during SFB 754 expeditions, models or experiments. All SFB 754 data are available for all scientists within the SFB 754 and have to be published as data publication by the end of the project, latest. The following regulations should provide transparency and free availability of the data among the scientists and at the same time protect the intellectual property rights of the author of the information

Status of Acropora palmata Populations off the Coast of South Caicos, Turks and Caicos Islands

This study is the first detailed assessment of A. palmata populations of the Turks and Caicos Islands. A total of 203 individual colonies and 62 thickets were tagged on five shallow reefs. Depth, percentages of living tissue, recent mortality and old skeleton were estimated. Presence of disease and predatory snails was noted, and disease spread and grazing rates of the snails estimated. Colonies were found in depths of 0.2 - 4 m. Living tissue for individual colonies (75.9% ± 2.2 SE) was significantly greater than for thickets (58.6% ± 3.6) and in both cases exceeded old skeleton (individuals: 22.7% ± 2.1 SE, thickets: 38.0% ± 3.4 SE). Percentage of recent mortality was very low (individuals: 1.3% ± 0.3 SE, thickets: 3.4% ± 0.7%). We found WBD (n = 2), white pox disease a (WPDa) (n = 7) and white pox disease b (WPDb) (n = 14) with greatly varying spreading rates. The WBD infected colonies showed an atypical spread from the top of the branch towards the base. Coralliophila abbreviata and C. caribaea affected 3 .7 54.7% of the populations (grazing rate: 4.29 cm 2 /day/snail ± 1.16 SE). South Caicos’ A. palmata populations are still in good condition, though increasing human disturbances combined with disease and predatory snails may threaten these populations

Impact and amelioration of sediment pollution on coral reefs of St. Lucia, West Indies

Includes Policy and Management Brief 1: Annex A2.# Appendix 1 of the Final Technical Report of project R766